JP2006091753A - Ic chip packaging substrate and optical communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an IC chip packaging substrate in which an optical element is packaged and an optical signal passing region is provided, and which is excellent in connection reliability. <P>SOLUTION: The IC chip packaging substrate is provided in which a conductor circuit and an inter-layer resin insulating layer are layered on both sides of the substrate, the optical element is packaged, and an optical path for optical signal transmission is formed. The IC chip packaging substrate is characterized in that an optical element sealing layer is formed in a manner coming in contact with the outer periphery of the optical element. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an IC chip mounting substrate and an optical communication device.

In recent years, attention has been focused on optical fibers mainly in the communication field. In particular, in the IT (information technology) field, communication technology using optical fibers is required to develop a high-speed Internet network.
The optical fiber has features such as (1) low loss, (2) high bandwidth, (3) small diameter and light weight, (4) non-induction, and (5) resource saving. Compared with communication systems using conventional metallic cables, the number of repeaters can be greatly reduced, making construction and maintenance easier, and making communication systems more economical and more reliable. Can be planned.

In addition, since optical fibers can simultaneously multiplex and transmit not only light of one wavelength but also light of many different wavelengths using a single optical fiber, a large-capacity transmission line that can be used for a variety of applications. It can be realized and can also support video services and the like.

Therefore, in such network communication such as the Internet, optical communication using an optical fiber is not only performed for communication of the backbone network, but also for communication between the backbone network and terminal devices (PC, mobile, game, etc.) It has also been proposed to be used for communication between each other.

Conventionally, as an optical transmission / reception system, for example, a pair of surface light emitting / receiving elements are mounted face-down using a flip chip bonding method on the upper surface of a multi-layer substrate (motherboard substrate), and directly below the center of the surface light emitting / receiving element. Are formed with through holes each having a core portion and a clad portion, and an optical waveguide extending linearly from just below one through hole to just below the other through hole is formed on the lower surface of the multilayer substrate. An optical transmission / reception system is disclosed (for example, see Patent Document 1).

JP 2000-81524 A

In the optical transmission / reception system described above, the optical element mounted with the fence down is not sealed by underfill, and dust and foreign matter enter between the optical element and the multilayer substrate. In some cases, transmission of an optical signal is hindered.
Further, in the above optical transmission / reception system, since the optical element is directly mounted on the multilayer substrate, the following problems also occur. That is, a fine pattern for flip-chip mounting an optical element and a rough pattern for connecting other mounting components are formed on the same substrate, and as a result, it is difficult to manufacture a multilayer substrate. At the same time, the yield during the production of the multilayer substrate has decreased, and the size of the multilayer substrate has increased.

Therefore, the present inventors have intensively studied to solve the above problems and completed the present invention.
That is, the IC chip mounting substrate of the first aspect of the present invention is an IC chip mounting in which a conductor circuit and an insulating layer are laminated on both sides of the substrate, an optical element is mounted, and an optical path for optical signal transmission is formed. Substrate for
An optical element sealing layer is formed so as to be in contact with the outer periphery of the optical element.
In the IC chip mounting substrate according to the first aspect of the present invention, it is preferable that a gap is formed in a portion of the optical signal transmission optical path in contact with the optical element.
The optical element sealing layer is preferably made of a resin.

The IC chip mounting substrate of the second aspect of the present invention is an IC chip mounting substrate in which a conductor circuit and an insulating layer are laminated on both surfaces of the substrate, an optical element is mounted, and an optical path for transmitting an optical signal is formed. Because
A cap member is attached so as to cover at least the optical element.
In the second IC chip mounting substrate, the cap member is preferably bonded and fixed with resin or solder.

In the IC chip mounting substrate of the first or second aspect of the present invention, the optical element is preferably a light receiving element and / or a light emitting element.

The optical communication device according to the third aspect of the present invention is a motherboard in which a conductor circuit and an insulating layer are laminated on at least one surface of a substrate, an optical waveguide is formed, and an optical path for transmitting an optical signal is further formed. An optical communication device in which an IC chip mounting substrate on which an optical element is mounted is mounted on a substrate,
An IC chip mounting substrate sealing layer is formed in contact with the outer periphery of the IC chip mounting substrate.

In the optical communication device according to the third aspect of the present invention, it is preferable that a gap is formed in a portion of the optical signal transmission optical path that is in contact with the IC chip mounting substrate.
The IC chip mounting substrate sealing layer is preferably made of a resin.

According to a fourth aspect of the present invention, there is provided an optical communication device comprising: a motherboard substrate having a conductor circuit and an insulating layer laminated on at least one surface of the substrate; an optical waveguide; and an optical signal transmission optical path. And an optical communication device on which an IC chip mounting substrate on which an optical element is mounted is mounted,
A cap member is attached so as to cover at least the IC chip mounting substrate.
In the optical communication device according to the fourth aspect of the present invention, it is desirable that the cap member is bonded and fixed with resin or solder.

In the IC chip mounting substrate of the first aspect of the present invention, since the optical element sealing layer is formed so as to be in contact with the outer periphery of the optical element, a gap opened to the outside between the optical element and the optical element mounting surface Is not present, and no dust or foreign matter enters the optical signal transmission optical path. Therefore, the transmission of the optical signal is not hindered due to the presence of the dust or the like.
Therefore, the IC chip mounting substrate of the first aspect of the present invention is excellent in reliability.

In the IC chip mounting substrate of the second aspect of the present invention, since the cap member is attached so as to cover at least the optical element, there is an open gap between the optical element and the optical element mounting surface. Therefore, no dust or foreign matter enters the optical signal transmission optical path. Therefore, the transmission of the optical signal is not hindered due to the presence of the dust or the like.
Therefore, the IC chip mounting substrate of the second aspect of the present invention is excellent in reliability.

Since the IC chip mounting substrates of the first and second aspects of the invention function as a so-called package substrate, the conductor circuit is basically formed in a fine pattern, thereby reducing the size and improving the yield. be able to.
Further, since the optical element is mounted and the optical path for transmitting the optical signal is formed, the input / output signals of the optical element can be transmitted through the optical path for transmitting the optical signal. Further, when an IC chip is mounted on the IC chip mounting substrate, the distance between the IC chip and the optical element is short, and the electrical signal transmission reliability is excellent.

In the optical communication device of the third aspect of the present invention, since the IC chip mounting substrate sealing layer is formed so as to be in contact with the outer periphery of the IC chip mounting substrate, the IC chip mounting substrate and the IC chip mounting substrate There is no gap open to the outside between the surface on which the board is mounted and dust or foreign matter does not enter the optical path for optical signal transmission.Therefore, due to the presence of this dust, Transmission of optical signals is not hindered.
Therefore, the optical communication device of the third aspect of the present invention is excellent in reliability.

In the optical communication device of the fourth aspect of the present invention, since the cap member is attached so as to cover the IC chip mounting substrate, the IC chip mounting substrate and the surface on which the IC chip mounting substrate is mounted There is no gap open to the outside, and no dust or foreign matter enters the optical path for optical signal transmission. Therefore, the transmission of optical signals is hindered by the presence of this dust etc. It is never done.
Therefore, the optical communication device of the fourth aspect of the present invention is excellent in reliability.

In the optical communication device according to the third or fourth aspect of the present invention, since electronic components and optical elements required for optical communication can be mounted and integrated on a motherboard substrate, the optical communication terminal device is thin. It can contribute to downsizing and downsizing.

First, the IC chip mounting substrate of the present invention will be described.
The IC chip mounting substrate according to the first aspect of the present invention is an IC chip mounting substrate in which a conductor circuit and an insulating layer are laminated on both sides of the substrate, an optical element is mounted, and an optical path for transmitting an optical signal is formed. Because
An optical element sealing layer is formed so as to be in contact with the outer periphery of the optical element.

In the IC chip mounting substrate of the first aspect of the present invention, since the optical element sealing layer is formed so as to be in contact with the outer periphery of the optical element, a gap opened to the outside between the optical element and the optical element mounting surface Is not present, and no dust or foreign matter enters the optical signal transmission optical path. Therefore, the transmission of the optical signal is not hindered due to the presence of the dust or the like.
Therefore, the IC chip mounting substrate of the first aspect of the present invention is excellent in reliability.

Since the IC chip mounting substrate according to the first aspect of the present invention functions as a so-called package substrate, the conductor circuit is basically formed in a fine pattern, so that the size can be reduced and the yield can be improved. .
Further, since the optical element is mounted and the optical path for transmitting the optical signal is formed, the input / output signals of the optical element can be transmitted through the optical path for transmitting the optical signal. Further, when an IC chip is mounted on the IC chip mounting substrate, the distance between the IC chip and the optical element is short, and the electrical signal transmission reliability is excellent.

In the IC chip mounting substrate of the first aspect of the present invention, the solder resist layer is usually formed on the outermost layer of the substrate in which the conductor circuit and the insulating layer are laminated on both sides.
In the present specification, an IC chip mounting substrate according to an embodiment in which a solder resist layer is formed as the outermost layer will be described below. Note that the solder resist layer is not necessarily formed.

In the IC chip mounting substrate of the first aspect of the present invention, as described above, when the solder resist layer is formed on the outermost layer, the optical element is in contact with the outer periphery of the optical element on the solder resist layer. A sealing layer is formed, and the lower gap (the gap between the lower surface of the optical element and the surface of the solder resist layer) is not opened to the outside.

Examples of the material for the optical element sealing layer include a thermosetting resin, a photosensitive resin, a resin in which a photosensitive group is added to a part of the thermosetting resin, and a resin composite including these and a thermoplastic resin. A body or the like can be used.

Examples of the thermosetting resin include epoxy resins, phenol resins, polyimide resins, polyester resins, bismaleimide resins, polyolefin resins, polyphenylene ether resins, polyphenylene resins, and fluorine resins.
Specific examples of the epoxy resin include, for example, novolak type epoxy resins such as phenol novolak type and cresol novolak type, dicyclopentadiene-modified alicyclic epoxy resins, and the like.

As said photosensitive resin, an acrylic resin etc. are mentioned, for example.
Examples of the resin in which a photosensitive group is added to a part of the thermosetting resin include, for example, those obtained by acrylate reaction of the thermosetting group of the thermosetting resin with methacrylic acid or acrylic acid. Can be mentioned.

Examples of the thermoplastic resin include phenoxy resin, polyether sulfone (PES), polysulfone (PSF), polyphenylene sulfone (PPS) polyphenylene sulfide (PPES), polyphenylene ether (PPE) polyetherimide (PI), and the like. It is done.

Moreover, it is desirable that the optical element sealing layer contains particles. When particles are included, the thixo ratio of the resin composition for forming the optical element sealing layer is adjusted by adjusting the particle diameter and blending amount, and the resin composition is applied to the outer periphery of the optical element. It is possible to impart characteristics suitable for the above.
Further, when the particles are blended, the thermal expansion coefficient can be adjusted by the blending amount, so that the thermal expansion coefficient is matched between the optical element sealing layer and the IC chip mounting substrate or the optical element. be able to.

Examples of the particles include inorganic particles, resin particles, and metal particles.
Examples of the inorganic particles include aluminum compounds such as alumina and aluminum hydroxide, calcium compounds such as calcium carbonate and calcium hydroxide, potassium compounds such as potassium carbonate, magnesium compounds such as magnesia, dolomite, basic magnesium carbonate, and talc. And silicon compounds such as silica and zeolite, and titanium compounds such as titania. These may be used alone or in combination of two or more. Moreover, the particle | grains of the mixed composition which mixed and fuse | melted at least 2 types of inorganic material may be sufficient.

Examples of the resin particles include those made of a thermosetting resin, a thermoplastic resin, and the like. Specifically, for example, amino resins (melamine resins, urea resins, guanamine resins, etc.), epoxy resins, phenol resins, and the like. , Phenoxy resin, polyimide resin, polyphenylene resin, polyolefin resin, fluororesin, bismaleimide-triazine resin and the like. These may be used alone or in combination of two or more.

Examples of the metal particles include gold, silver, copper, tin, zinc, stainless steel, aluminum, nickel, iron, lead, and the like. These may be used alone or in combination of two or more.
The metal particles are preferably coated with a resin or the like in order to ensure insulation.
Further, the optical element sealing layer is desirably low stress so as to adapt to the warp of the IC chip mounting substrate.

When forming the optical element sealing layer, the lower limit of the viscosity of the resin composition as the material is preferably 100 Pa · s, and the upper limit is preferably 1000 Pa · s.
If it is less than 100 Pa · s, since the fluidity of the resin composition is too good, it may be impossible to seal only a desired portion around the optical element. If it exceeds 1000 Pa · s, the resin composition is too hard. This is because there may be a portion that does not adhere to the outer peripheral portion and cannot be completely sealed. A more desirable lower limit is 200 Pa · s, and a more desirable upper limit is 500 Pa · s.
The viscosity can be measured with a BH viscometer.

When the particles are contained in the optical element sealing layer, the lower limit of the amount of the particles is desirably 70% by weight, and the upper limit is desirably 85% by weight. If the blending amount of the particles is less than 70% by weight, it is difficult to achieve the above-described desirable viscosity (100 Pa · s). This is because a portion that does not adhere to the portion and cannot be completely sealed may occur.

When the particles are contained in the optical element sealing layer, the particles preferably have a particle diameter of 1 to 500 μm or an average particle diameter of 10 to 100 μm, which satisfies both ranges. It is more desirable. The particle diameter means the length of the longest part of the particle.
When the particle diameter is less than 1 μm, the fluidity of the resin composition may be too good, and when the average particle diameter exceeds 100 μm, the viscosity may not be stable.

Moreover, when forming the said optical element sealing layer, as for the thixo ratio of the resin composition used as a material, it is desirable that the minimum is 1.5 and the upper limit is 5.0. If it is less than 1.5, the fluidity of the resin composition may be too good, and if it exceeds 5.0, the resin composition may be too dried and may not be used as a resin paste.
A more desirable lower limit is 1.5, and a more desirable upper limit is 3.0. This is because this range is particularly suitable for application as a resin paste.
The thixo ratio can be measured with a BH viscometer.

The optical element sealing layer can be formed by potting an uncured resin composition and then performing a curing treatment.
When the optical element sealing layer is formed by potting, the optical element sealing layer may be formed so as to cover the optical element as long as the optical element sealing layer is in contact with the outer periphery of the optical element. .

In addition, since the IC chip is usually mounted on the same surface as the surface on which the optical element is mounted on the IC chip mounting substrate of the first aspect of the present invention, the optical element sealing layer includes the IC chip. After mounting, the IC chip and the optical element may be integrally covered.

In the IC chip mounting substrate according to the first aspect of the present invention, a gap between the lower surface of the optical element and the surface of the solder resist layer, more specifically, a portion in contact with the optical element of the optical path for optical signal transmission. It is desirable that a gap is formed.
In other words, it is desirable that an optical element sealing layer is not formed in a portion of the optical signal transmission optical path that is in contact with the optical element.
The reason will be briefly described below.

The first reason is that when the optical element sealing layer is formed in the entire gap between the lower surface of the optical element and the surface of the solder resist layer, and the optical element sealing layer has a low transmittance, a high speed optical signal is generated. In particular, when particles are blended to adjust the thermal expansion coefficient, the transmittance of the optical element sealing layer is 75 even when the transmittance of the resin component is 90% / mm or more. This is because the speed is reduced to about ˜85% / mm, so that high-speed transmission of an optical signal is more difficult.
In addition, the refractive index of the optical element sealing layer may change depending on the temperature, and if the refractive index of the optical element sealing layer changes during use, the optical signal transmission capability may decrease.
In addition, when the optical element sealing layer is formed in the entire gap between the lower surface of the optical element and the surface of the solder resist layer, a void (void) is likely to be generated at the center of the optical element sealing layer. Usually not constant. In this way, voids may or may not be formed in the optical element sealing layer. Further, when the size of the voids is different, the optical signal is refracted at the void portion, so the optical signal is This is because it is difficult to always transmit in a predetermined direction, and the transmission loss of the optical signal may increase or the optical signal may not be transmitted.

The second reason is that, in the IC chip mounting substrate of the first aspect of the present invention, as will be described later, the spread of the transmission light can be suppressed and the optical signal can be transmitted more reliably. A microlens may be disposed in the transmission optical path. When the microlens is disposed in this way, a gap is formed in a portion of the optical signal transmission optical path that is in contact with the optical element. Is particularly desirable.

This is because, in general, when using a microlens to collect light, the greater the difference between the refractive index of the microlens and its surrounding refractive index, the shorter the collection distance. When the microlens is made of resin, the refractive index is about 1.4 to 1.6, and when the microlens is made of glass, the refractive index is about 1.8. Therefore, from the viewpoint of increasing the difference between the refractive index of the microlens and the surrounding refractive index, an optical element sealing layer is formed in a portion of the optical signal transmission optical path that is in contact with the optical element. It is more desirable to be a gap (for example, an air layer having a refractive index of 1.0).

In addition, when the difference between the refractive index of the microlens and the refractive index around it is small, it is necessary to reduce the radius of curvature of the microlens in order to collect the transmitted light. When the radius is increased, the allowable value of the formation position decreases, and transmission loss increases with a slight positional deviation. On the other hand, as described above, when the difference between the refractive index of the microlens and the surrounding refractive index is increased (that is, when a gap is formed in the portion of the optical signal transmission optical path in contact with the optical element) ), The transmission light can be condensed even if the curvature radius of the microlens is small, so that the allowable value of the formation position of the microlens is increased and the transmission loss can be reduced.

As a method for preventing the uncured resin composition from flowing into the gap between the optical element and the solder resist layer, for example, a resin composition used when forming the optical element sealing layer as described above On the surface of the solder resist layer near the outer periphery of the optical element, a method of blending particles having a particle diameter larger than the gap distance between the optical element and the solder resist layer, For example, a method of performing a surface treatment that can prevent the inflow of the uncured resin composition into the gap may be used.

Examples of a method for increasing the viscosity of the uncured resin composition include a method for increasing the amount of particles blended in the resin composition.
When blending particles having a particle size larger than the gap distance between the optical element and the solder resist layer, the gap distance is usually about 30 to 100 μm, and a flip chip mounting type optical element is used. The distance of the gap when used may be appropriately determined in consideration of the general case of about 50 μm.

Moreover, as said surface treatment given beforehand to the predetermined part of the said soldering resist layer surface, a water-repellent coating etc. are mentioned, for example.

Moreover, when the resin especially suitable for formation of the said optical element sealing layer was examined, the following results were obtained.
That is, each of the resin compositions A to C is applied with a dispenser to the end portions of two glass plates arranged so that the gap is 50 μm or 300 μm by a spacer, and after curing the resin composition, The distance that entered the gap between the glass plates from the edge of the glass plate was observed by cross-cutting the glass plate, and the fluidity of the resin composition was evaluated at the entered distance.
The resin A is a resin composition having a viscosity of 235 Pa · s and a thixo ratio of 1.7, in which 75% by weight of silica particles having an average particle diameter of 25 μm are blended with an epoxy resin component. As the resin C, a resin composition (CCN800D, manufactured by Kyushu Matsushita Electric Co., Ltd.) having a viscosity of 12 Pa · s and a thixo ratio of 1.1, in which particles having a maximum particle size of 30 μm or less are blended with an epoxy resin component, and an epoxy as the resin C A resin composition having a viscosity of 8 Pa · s and a thixo ratio of 1.3 (EPA 521D, manufactured by Kyushu Matsushita Electric Industrial Co., Ltd.) in which particles having a maximum particle size of 20 μm or less were blended with the resin component of the system.

As a result, when Resin A was used, the fluidity at a gap of 50 μm (distance entering the gap of the glass plate) was 1.0 to 2.0 mm, and the fluidity at a gap of 300 μm was 4.0 to 5. 0.0 mm. On the other hand, when resin A and resin B were used, both the fluidity at a gap of 50 μm and the fluidity at a gap of 300 μm were 40 mm or more.
In addition, it replaces with one side (lower side) glass substrate for the copper clad laminated board by which the layer which consists of the resin composition for solder resist layers (the Hitachi Chemical Co., Ltd. make, RPZ1) was formed on the surface, and performed the same examination. As a result, the same results as in the case of using two glass plates were obtained.
Also from these things, it became clear that the resin composition which has the characteristic mentioned above is especially suitable as an optical element sealing layer.

In the IC chip mounting substrate of the present invention, as described above, a gap is formed in the portion of the optical signal transmission optical path in contact with the optical element, and the optical element sealing layer is not formed. In some cases, an optical element sealing layer may be formed on a portion of the optical signal transmission optical path that is in contact with the optical element.

In the IC chip mounting substrate according to the first aspect of the present invention, when a solder resist layer is formed through the substrate and the insulating layer, an optical signal transmission optical path that also penetrates the solder resist layer is arranged. It is installed.
In such an IC chip mounting substrate, an optical signal can be transmitted through the optical signal transmission optical path.
Further, in the IC chip mounting substrate, an optical element is mounted on the outermost layer or the like on one surface side, and another optical component (for example, an optical waveguide or the like) is mounted on the other surface side. By connecting to an external substrate via solder or the like, information is exchanged between the optical element mounted on the IC chip mounting substrate of the present invention and the optical component mounted on the external substrate. Via an optical signal.

Specific forms of the optical path for transmitting an optical signal include a collective through-hole structure and an individual through-hole structure. These specific structures will be described later with reference to the drawings.
Further, the optical path for transmitting an optical signal may be constituted only by a gap, or a part thereof may be filled with a resin composition. Specifically, for example, a resin composition is filled in a portion that penetrates the substrate and the insulating layer, and a portion that penetrates the solder resist layer is constituted by a gap. Furthermore, the resin composition may be filled in a portion penetrating the substrate, the insulating layer, and the solder resist layer.
This is because the strength of the IC chip mounting substrate can be increased by filling the resin composition.
In the IC chip mounting substrate according to the first aspect of the present invention, the resin composition is filled in the portion of the optical signal transmission optical path that penetrates the substrate and the insulating layer, and the portion that penetrates the solder resist layer is constituted by the gap. It is desirable that This is because the substrate and the insulating layer usually have high adhesion to the resin, and the solder resist layer has low adhesion to the resin. Further, as will be described later, a microlens may be disposed in a portion penetrating the solder resist layer.
Further, as described above, it is desirable that a gap is formed in a portion of the optical signal transmission optical path that is in contact with the optical element.

The resin component of the resin composition is not particularly limited as long as it has little absorption in the communication wavelength band. For example, a part of a thermosetting resin, a thermoplastic resin, a photosensitive resin, or a thermosetting resin is included. Examples thereof include photosensitive resins.
Specifically, for example, epoxy resins, UV curable epoxy resins, polyolefin resins, PMMA (polymethyl methacrylate), deuterated PMMA, acrylic resins such as deuterated fluorinated PMMA, polyimide resins such as fluorinated polyimide, Examples thereof include silicone resins such as deuterated silicone resins, polymers produced from benzocyclobutene, and the like.

In addition to the resin component, the resin composition may contain particles such as resin particles, inorganic particles, and metal particles. By including these particles, the thermal expansion coefficient can be matched between the optical path for optical signal transmission and the substrate, insulating layer, solder resist layer, etc. It can also be granted.
Examples of the resin particles include a thermosetting resin, a thermoplastic resin, a photosensitive resin, a resin in which a part of the thermosetting resin is made photosensitive, a resin composite of a thermosetting resin and a thermoplastic resin, Examples include a composite of a photosensitive resin and a thermoplastic resin.

Specifically, for example, thermosetting resins such as epoxy resins, silicone resins, phenol resins, polyimide resins, bismaleimide resins, polyphenylene resins, polyolefin resins, fluororesins; thermosetting groups of these thermosetting resins (for example, , An epoxy group in an epoxy resin) by reacting methacrylic acid or acrylic acid with an acrylic group; phenoxy resin, polyether sulfone (PES), polysulfone (PSF), polyphenylene sulfone (PPS), polyphenylene sulfide ( Examples thereof include thermoplastic resins such as PPES), polyphenyl ether (PPE), and polyetherimide (PI); and photosensitive resins such as acrylic resins.
Moreover, the resin composite of the said thermosetting resin and the said thermoplastic resin, the resin to which the said acrylic group was provided, the said photosensitive resin, and the said thermoplastic resin can also be used.
Moreover, as the resin particles, resin particles made of rubber can be used.

Examples of the inorganic particles include aluminum compounds such as alumina and aluminum hydroxide, calcium compounds such as calcium carbonate and calcium hydroxide, potassium compounds such as potassium carbonate, magnesium compounds such as magnesia, dolomite, and basic magnesium carbonate. And silicon compounds such as silica and zeolite, and titanium compounds such as titania. Moreover, what consists of phosphorus or a phosphorus compound can also be used as said inorganic particle. Moreover, the particle | grains of the mixed composition which mixed and fuse | melted at least 2 types of inorganic material may be sufficient.

Examples of the metal particles include Au, Ag, Cu, Pd, Ni, Pt, Fe, Zn, Pb, Al, Mg, and Ca.
These resin particles, inorganic particles and metal particles may be used alone or in combination of two or more.

Moreover, the shape of the said particle | grain is not specifically limited, For example, spherical shape, elliptical spherical shape, crushed shape, polyhedral shape etc. are mentioned. Among these, spherical or elliptical spheres are desirable. This is because, since the particles have no corners, cracks and the like are less likely to occur in the resin composition filled in the optical path for optical signal transmission.
In addition, the particle size of the particles (the length of the longest part of the particles) is preferably shorter than the communication wavelength. This is because if the particle size is longer than the communication wavelength, the transmission of the optical signal may be hindered depending on the case.

The lower limit of the average particle size of the particles is preferably 0.01 μm, more preferably 0.1 μm, and particularly preferably 0.2 μm. On the other hand, the upper limit of the average particle size of the particles is desirably 0.8 μm, and more desirably 0.6 μm. If it is the range of this particle size, you may contain the particle | grains of 2 or more types of different particle sizes. In the present specification, the particle diameter refers to the length of the longest part of the particle.

The lower limit of the amount of particles contained in the resin composition is desirably 10% by weight, and the upper limit is desirably 50% by weight. If the blending amount of the particles is less than 10% by weight, the effect of blending the particles may not be obtained. If the blending amount of the particles exceeds 50% by weight, it is difficult to fill the optical path for optical signal transmission. It is. A more desirable lower limit of the blending amount of the particles is 20% by weight, and a more desirable upper limit of the blending amount of the particles is 40% by weight.

In the IC chip mounting substrate according to the first aspect of the present invention, when the resin composition is filled in the portion of the optical signal transmission optical path that penetrates the substrate and the insulating layer, the optical signal transmission optical path The diameter of the cross section of the portion penetrating the solder resist layer may be smaller than the diameter of the cross section of the portion formed in the substrate and the insulating layer.
When the diameter of the cross section of the portion that penetrates the solder resist layer is smaller than the diameter of the cross section of the portion that penetrates the substrate and the insulating layer, the boundary between the portion that penetrates the insulating layer of the optical path for optical signal transmission and the resin composition The portion is covered with a part of the solder resist layer, and the boundary portion and the vicinity of the outer edge of the resin composition are bonded by the solder resist layer, and as a result, the resin composition and This is because peeling and cracking between the substrate and the insulating layer are less likely to occur and the reliability is improved.

The specific diameter of the cross section of the portion that penetrates the solder resist layer of the optical path for transmitting an optical signal is particularly limited as long as it is smaller than the diameter of the cross section of the portion formed on the substrate and the insulating layer. However, it may be appropriately selected according to the design of the IC chip mounting substrate, but it is usually desirable to be about 50 to 490 μm.

A conductor layer may be formed on the wall surface of the optical path for transmitting an optical signal.
By forming the conductor layer, irregular reflection of light on the wall surface of the optical path for optical signal transmission can be reduced, and the transmission performance of the optical signal can be improved. The conductor layer may be formed from one layer or may be formed from two or more layers.
Examples of the material for the conductor layer include copper, nickel, chromium, titanium, and noble metals.
In some cases, the conductor layer serves as a through hole, that is, serves to electrically connect conductor circuits sandwiching the substrate or conductor circuits sandwiching the substrate and the insulating layer. Can do.

The conductor layer may be formed of a glossy metal (for example, gold, silver, nickel, platinum, aluminum, rhodium, etc.). When a conductor layer made of such a glossy metal is formed, the optical signal is suitably reflected on the wall surface of the optical path for transmitting the optical signal, and it is difficult for the signal intensity to be attenuated. is there.
Furthermore, the surface of the conductor layer itself may be roughened by etching or the like.

Moreover, you may provide the coating layer and roughening layer which consist of tin, titanium, zinc, etc. further on the said conductor layer. By providing the coating layer and the roughening layer, the irregular reflection of light is further reduced and the transmission performance of the optical signal is improved, or the adhesion between the optical path for transmitting the optical signal and the substrate or the insulating layer is improved. be able to.

Moreover, the part which penetrates the board | substrate and insulating layer of the optical path for optical signal transmission with which the said resin composition was filled, and the said conductor layer may be in contact with the board | substrate or the insulating layer through the roughening surface. This is because when the optical path for transmitting an optical signal or the like is in contact via a roughened surface, the optical path for transmitting an optical signal or the like is less likely to be peeled off due to excellent adhesion to a substrate or an insulating layer.

On the IC chip mounting substrate of the first aspect of the present invention, optical elements such as a light receiving element and a light emitting element are mounted.
Examples of the light receiving element include PD (photodiode), APD (avalanche photodiode), and the like.
These may be properly used in consideration of the configuration of the IC chip mounting substrate, required characteristics, and the like.
Examples of the material for the light receiving element include Si, Ge, and InGaAs.
Of these, InGaAs is desirable because of its excellent light receiving sensitivity.

Examples of the light emitting element include LD (semiconductor laser), DFB-LD (distributed feedback type-semiconductor laser), LED (light emitting diode), infrastructure type or oxide constriction type VCSEL (surface emitting semiconductor laser). .
These may be properly used in consideration of the configuration and required characteristics of the IC chip mounting substrate.

Examples of the material of the light emitting element include a compound of gallium, arsenic and phosphorus (GaAsP), a compound of gallium, aluminum and arsenic (GaAlAs), a compound of gallium and arsenic (GaAs), a compound of indium, gallium and arsenic (InGaAs), Indium, gallium, arsenic and phosphorus compounds (InGaAsP) can be used.
These may be properly used in consideration of the communication wavelength. For example, when the communication wavelength is 0.85 μm band, GaAlAs can be used, and when the communication wavelength is 1.3 μm band or 1.55 μm band. InGaAs or InGaAsP can be used.
Each of these light emitting elements and light receiving elements may be a multi-channel array element.

The mounting position of the optical element is preferably the surface of the IC chip mounting substrate. As described above, when the optical element is mounted on the surface of the IC chip mounting substrate, when a problem occurs in one optical element, only the optical element needs to be replaced.
It is desirable that electronic parts such as capacitors are also mounted on the surface of the IC chip mounting substrate. This is because, as in the case of the optical element described above, it is possible to replace only the parts that have inconveniences.

In the IC chip mounting substrate, a microlens may be disposed in the optical path for transmitting an optical signal.
This is because by arranging the microlens, transmission light can be condensed and transmission loss of an optical signal can be suppressed.

Specifically, for example, when a resin composition is filled in a portion that penetrates the substrate, insulating layer, and solder resist layer of the optical path for transmitting an optical signal, the resin composition is directly or directly bonded to the end of the resin composition. The microlens may be disposed through the agent, and the resin composition is filled in the portion that penetrates the substrate and the insulating layer of the optical path for optical signal transmission, and the resin composition is filled in the portion that the solder resist layer penetrates the gap. In the case where the product is not filled, a microlens may be disposed at the end of the resin composition and in a portion penetrating the solder resist layer of the optical path for transmitting an optical signal.
Moreover, the microlens may be arrange | positioned in the light-receiving part of the mounted light receiving element, or the light emission part of a light emitting element.

The microlens is not particularly limited, and examples thereof include those used in optical lenses, and specific examples of the material include optical glass and optical lens resins. Examples of the resin for optical lenses include materials similar to the polymer materials described as the resin composition that fills the optical path for optical signal transmission, such as acrylic resin and epoxy resin.

The refractive index of the microlens is not particularly limited, and may be the same as or higher than the refractive index of the resin composition filled in the optical path for optical signal transmission.
When the refractive index of the micro lens is the same as the refractive index of the optical path for optical signal transmission, since the reflection of the optical signal does not occur at the interface between them, the optical signal can be transmitted more reliably, When the refractive index of the microlens is larger than the refractive index of the optical path for transmitting an optical signal, the optical signal can be more condensed in a desired direction, so that the optical signal can be transmitted more reliably. .

In addition, examples of the shape of the microlens include a convex lens having a convex surface only on one side, and in this case, the radius of curvature of the convex surface of the lens takes into account the design of the optical path for transmitting an optical signal, etc. What is necessary is just to select suitably. Specifically, for example, when it is necessary to increase the focal length, it is desirable to reduce the radius of curvature, and when it is necessary to shorten the focal length, it is desirable to increase the radius of curvature. However, as described above, it is desirable that the radius of curvature of the microlens is small from the viewpoint of increasing the allowable value of the formation position of the microlens.
The shape of the microlens is not limited to a convex lens, and may be any shape that can collect an optical signal in a desired direction.

It is desirable that the microlens has a communication wavelength light transmittance of 70% or more.
This is because if the transmittance of the communication wavelength light is less than 70%, the loss of the optical signal is large, leading to a decrease in the transmission property of the optical signal. The transmittance is more preferably 90% or more.
In the present specification, the transmittance of communication wavelength light refers to the transmittance of communication wavelength light per 1 mm length. Specifically, for example, when the light having the intensity I ₁ is incident on the microlens and passes through the microlens by 1 mm, and the intensity of the emitted light is I ₂ , This is a value calculated by equation (1).

Transmittance (%) = (I ₂ / I ₁ ) × 100 (1)

In addition, the said transmittance | permeability means the transmittance | permeability measured at 25-30 degreeC.

The microlens may include particles such as resin particles, inorganic particles, and metal particles.
By including particles, the strength of the microlens is improved and the shape is more reliably maintained, and the thermal expansion coefficient is matched between the IC chip mounting substrate and the multilayer printed wiring board. This is because cracks and the like due to the difference in thermal expansion coefficient are less likely to occur.

When the microlens includes particles, it is desirable that the refractive index of the resin component of the microlens and the refractive index of the particles be approximately the same. Therefore, it is desirable that the particles included in the microlens are obtained by mixing two or more types of particles having different refractive indexes so that the refractive index of the particles is approximately the same as the refractive index of the resin component.
Specifically, for example, when the resin component is an epoxy resin having a refractive index of 1.53, particles included in the microlens are silica particles having a refractive index of 1.46 and titania particles having a refractive index of 2.65. It is desirable to mix and dissolve them into particles.
Examples of the method of mixing the particles include a kneading method, a method of dissolving two or more types of particles and mixing them, and then forming particles.
Specific examples of the particles include the same particles as those added to the resin composition.

Moreover, the shape of the said particle | grain is not specifically limited, For example, spherical shape, elliptical spherical shape, crushed shape, polyhedral shape etc. are mentioned. Among these, spherical or elliptical spheres are desirable. This is because the spherical or oval spherical particles have no corners, so that cracks and the like are less likely to occur in the microlens. Furthermore, when the shape of the particle is spherical or elliptical, light is not easily reflected by the particle, and the loss of optical signal is reduced.

The particle size (maximum particle length) of the particles is not particularly limited, but the upper limit is preferably 0.8 μm and the lower limit is preferably 0.01 μm.
The micro lens is usually arranged using an ink jet device or a dispenser. The inner diameter of the application nozzle of the ink jet device and the nozzle inner diameter of the dispenser are 20 μm, which is the current minimum size, and the particle size Is in the above range, the nozzle can be applied without clogging.
The lower limit of the particle size is more preferably 0.1 μm.
This is because it is more preferable that the particle size is in this range from the viewpoint of stability of viscosity in application by an ink jet device or a dispenser or the like and variation in application amount.

A desirable lower limit of the amount of particles contained in the microlens is 5% by weight, and a more desirable lower limit is 10% by weight. On the other hand, the desirable upper limit of the blending amount of the particles is 60% by weight, and the more desirable upper limit is 50% by weight. If the blending amount of the particles is less than 5% by weight, the effect of blending the particles may not be obtained. If the blending amount of the particles exceeds 60% by weight, the transmission of the optical signal may be hindered. It is.

Moreover, the said micro lens may be directly attached to the edge part of the resin composition, and may be arrange | positioned through the optical adhesive agent.
The optical adhesive is not particularly limited, and an optical adhesive such as epoxy resin, acrylic resin, or silicone resin can be used.
The characteristics of the optical adhesive are: viscosity: 0.2 to 1.0 Pa · s, refractive index: 1.4 to 1.6, light transmittance: 80% / mm or more, coefficient of thermal expansion (CTE): 4. 0 × is desirably ^{10 -5 ~9.0 × 10 -5 (/} ℃).
The thickness of the optical adhesive is desirably 50 μm or less.

In addition, a surface treatment may be performed on a region where the microlens is disposed.
When resin for forming a microlens is applied with an ink jet apparatus, etc., due to variations in process conditions until the formation of the solder resist layer and wettability variations at the location where the microlens is placed due to standing time In addition, the shape of the microlens, particularly the sag height, is likely to vary, but the surface treatment or the like with a water repellent coating agent can be performed to suppress the sag height variation.

Examples of the surface treatment include treatment with a water-repellent coating agent such as a fluorine-based polymer coating agent (surface tension 10 to 12 mN / m), water-repellent treatment with CF ₄ plasma, and hydrophilic treatment with O ₂ plasma.
A specific method of the surface treatment will be briefly described.
In the case of performing the treatment with the water repellent coating agent, first, a mask having an opening corresponding to the portion where the microlens of the IC chip mounting substrate is formed is performed, and then, repellent by spray coating or spin coater coating. After applying the water coating agent, the water repellent coating agent is naturally dried, and the surface treatment is completed by peeling off the mask. In addition, the thickness of the water repellent coating agent layer is usually about 1 μm.
Here, a mesh plate or a resist-formed mask may be used.
When the treatment with the water repellent coating agent is performed, the entire exposed surface including the wall surface of the solder resist layer may be treated with the water repellent coating agent without using a mask. This is because the solder resist layer fulfills the effect of a dam when forming a microlens.

In the case of performing the water repellent treatment using the CF ₄ plasma, first, a mask having an opening corresponding to a portion where the microlens of the IC chip mounting substrate is formed is performed, and then the CF ₄ plasma treatment is performed. Further, the surface treatment is completed by removing the mask.
Here, a resist-formed mask may be used.
Further, when performing the hydrophilic treatment with the O ₂ plasma, first, a mask corresponding to the portion where the microlens of the IC chip mounting substrate is formed is opened, and then the O ₂ plasma treatment is performed. Further, the surface treatment is finished by removing the mask.
Here, a metal plate or a resist-formed mask may be used.
Moreover, it is desirable to combine the water repellent treatment (including treatment with a water repellent coating agent) and a hydrophilic treatment.
In the present specification, the sag height of the microlens refers to the height of the portion protruding from the surface of the solder resist layer. When the solder resist layer is not formed on the IC chip mounting substrate, it means the height of the portion protruding from the surface of the outermost layer.

In the IC chip mounting substrate of the present invention, a solder resist layer is formed on the outermost layer. The lower limit of the thickness of the solder resist layer is preferably 10 μm, and preferably 15 μm. More desirable. On the other hand, the upper limit is desirably 40 μm, and more desirably 30 μm.

In the IC chip mounting substrate of the present invention, the conductor circuits sandwiching the substrate are connected via through holes, and the conductor circuits sandwiching the insulating layer are connected via via holes. Is desirable. This is because the high-density wiring of the IC chip mounting substrate can be realized and the size can be reduced.

Next, an IC chip mounting substrate according to the first aspect of the present invention will be described with reference to the drawings.
FIG. 1A is a cross-sectional view schematically showing an embodiment of an IC chip mounting substrate according to the first aspect of the present invention, and FIG. It is a partial expanded sectional view which shows a part of one Embodiment typically. FIG. 1A shows an IC chip mounting substrate on which an IC chip is mounted.

As shown in FIG. 1, the IC chip mounting substrate 120 of the first aspect of the present invention includes a conductor circuit 124 and an insulating layer 122 laminated on both surfaces of a substrate 121, and between conductor circuits sandwiching the substrate 121, and Conductor circuits sandwiching the insulating layer 122 are electrically connected by through holes 129 and via holes 127, respectively. A solder resist layer 134 is formed on the outermost layer.
In the IC chip mounting substrate 120, an optical signal transmission optical path 142 is formed so as to penetrate the substrate 121, the insulating layer 122, and the solder resist layer 134.

In the optical signal transmission optical path 142, a resin composition 142a is filled in a portion penetrating the substrate 121 and the insulating layer 122, a conductor layer is formed around the resin composition 142a, and a solder resist layer is formed. A microlens 149 is disposed in a portion that penetrates through 134.
Input / output signals of the optical elements (the light emitting element 138 and the light receiving element 139) mounted on the IC chip mounting substrate 120 are transmitted via the optical signal transmission optical path 142.
In addition, the part which penetrates the soldering resist layer of the optical path for optical signal transmission may be formed by the space | gap 142b as shown in FIG. 1, and may be filled with the resin composition. Further, the conductor layer 145 may not be formed around the portion of the optical signal transmission optical path that passes through the substrate 121 and the insulating layer 122, and the conductor layer 145 may be formed from one layer as shown in FIG. It may be comprised, and may be comprised from two or more layers.

On one surface of the IC chip mounting substrate 120, the light emitting element 138 and the light receiving element 139 are connected via the solder connection part 144 so that the light emitting part 138 a and the light receiving part 139 a face the optical path 142 for optical signal transmission. Further, the IC chip 140 is surface mounted via a solder connection portion 143.
Further, an optical element sealing layer 148 is formed on the solder resist layer 134 on one surface so as to be in contact with the outer circumferences of the light emitting element 138 and the light receiving element 139, and the light emitting element 138 and the light receiving element 139. A gap is formed in a portion in contact with the optical path for transmitting an optical signal. Accordingly, the optical element sealing layer 148 is not formed on the portion of the optical signal transmission optical path that is in contact with the light receiving element 138 or the light receiving element 139.
By forming such an optical element sealing layer 148, dust or foreign matter does not enter the optical signal transmission optical path 142, and transmission of an optical signal is hindered by the dust or foreign matter. Nor.
In addition, solder bumps 137 are formed on the solder resist layer 134 on the other surface of the IC chip mounting substrate 120.

In the IC chip mounting substrate 120 having such a configuration, an optical signal transmitted from the outside via an optical fiber, an optical waveguide or the like (not shown) is received by the light receiving element 139 via the optical path 142 for transmitting an optical signal. After being received by the (light receiving portion 139a), it is converted into an electric signal by the light receiving element 139, and further sent to the IC chip 140 via the solder connection portions 143 and 144, the conductor circuit 124, the via hole 127, the through hole 129, and the like. It will be.

In addition, the electrical signal sent from the IC chip 140 is sent to the light emitting element 138 through the solder connection portions 143 and 144, the conductor circuit 124, the via hole 127, the through hole 129, and the like, and then the optical signal is output from the light emitting element 138. The optical signal transmitted from the light emitting element 138 (light emitting unit 138a) is sent to an external optical element (such as an optical fiber or an optical waveguide) via the optical signal transmission optical path 142.

In the IC chip mounting substrate of the present invention, since the light / electric element conversion is performed in the light receiving element and the light emitting element mounted at a position close to the IC chip, the electric signal transmission distance is short, and the signal transmission reliability is excellent. It is possible to cope with higher speed communication.

Further, in the IC chip mounting substrate 120, since the solder bump 137 is formed on the solder resist layer 134 via the metal plating layer, the electric signal sent from the IC chip is converted into an optical signal as described above. After that, not only the optical signal transmission optical path 142 and the like are sent to the outside, but also the solder bumps 137 are sent to the external substrate.

When the solder bumps are formed in this way, the IC chip mounting substrate can be connected to an external substrate such as a motherboard substrate via the solder bumps. In this case, the self-alignment of the solder By the action, the IC chip mounting substrate can be arranged at a predetermined position.

The self-alignment action refers to an action in which the solder tends to exist in a more stable shape near the center of the solder bump forming opening due to the fluidity of the solder during reflow processing, and this action means that the solder is a solder resist layer. It is thought that this occurs due to the strong surface tension that tends to become spherical when the metal is repelled and the solder adheres to the metal.
When this self-alignment action is used, when the IC chip mounting substrate is connected to the external substrate via the solder bumps, even if a positional deviation occurs between both before reflow, The IC chip mounting substrate moves, and the IC chip mounting substrate can be attached to an accurate position on the external substrate.
Therefore, when an optical signal is transmitted through the optical signal transmission optical path between the light receiving element and the light emitting element mounted on the IC chip mounting board and an external optical element, the IC chip mounting board If the mounting position of the mounted light receiving element or light emitting element is accurate, an accurate optical signal can be transmitted between the IC chip mounting substrate and the external substrate.

In the IC chip mounting substrate of the present invention, a dam 150 may be formed between the optical element 138 and the solder resist layer, as shown in a partial sectional view in FIG. By forming the dam, the optical element sealing layer can be formed only on a desired portion on the solder resist layer.
In particular, when the optical element sealing layer is formed by potting, the optical element sealing layer can be prevented from flowing into the optical path for transmitting an optical signal (directly below the light receiving portion 138a of the light emitting element 138). It is suitable that a dam is formed.

For example, the dam is formed by printing an epoxy resin, a silicone resin or the like, punching into a frame shape by a punching press, or cutting out into a frame shape by router processing, etc. with an adhesive. It can be performed by bonding or the like. In view of the fact that the gap between the optical element and the solder resist layer is usually about 50 μm, it is desirable to form a dam by printing an epoxy resin, a silicone resin or the like.

Further, the formation position of the dam is not particularly limited, and may be appropriately selected according to the design of the IC chip mounting substrate. For example, it is inside the solder connection portion that connects the IC chip mounting substrate and the optical element. Thus, it may be formed at a position outside the optical path for optical signal transmission (see FIG. 1B). Further, it may be formed between the IC chip mounting substrate and the optical element and outside the solder connection portion. Furthermore, you may form in the position where a part of solder connection part will contact | connect an optical element sealing layer.
In addition, when the dam is formed, a resin composition having excellent fluidity can be used as the resin composition for forming the optical element sealing layer, which is suitable for forming the optical element sealing layer. The degree of freedom in selecting the viscosity, maximum particle diameter and average particle diameter of the resin composition, particle content, and thixo ratio is further improved. Specifically, the same resin composition as that used to seal a conventionally known IC chip can be suitably used.

In the IC chip mounting substrate according to the first aspect of the present invention, the optical elements such as the light receiving element and the light emitting element to be mounted are not limited to the one-channel type as shown in FIG. There may be.
When a multi-channel optical element is mounted, an optical signal transmission optical path having a shape corresponding thereto (for example, an optical signal transmission optical path with a collective through-hole structure or an optical signal transmission optical path with an individual through-hole structure) is provided. Need to form. Hereinafter, an IC chip mounting substrate in which a multichannel optical element is mounted will be described with reference to the drawings.

In the IC chip mounting substrate according to the first aspect of the present invention, the optical element sealing layer to be formed is not limited to one made of resin, and may be made of solder, for example. Hereinafter, this will be described with reference to FIG.
FIG.1 (c) is a fragmentary sectional view which shows typically a part of another example of the board | substrate for IC chip mounting of this invention.

In the IC chip mounting substrate shown in FIG. 1C, the light emitting element 138 is surface-mounted on the solder resist layer via the solder connection portion 144, like the IC chip mounting substrate 120 shown in FIG. ing.
An optical element sealing layer 178 made of solder is formed on the solder resist layer 134 so as to be in contact with the outer periphery of the light emitting element 138. The optical element sealing layer 178 made of solder is solder-connected to an optical element sealing layer forming pad formed on the interlayer insulating layer 172. Therefore, the solder resist layer 134 is provided with an opening for forming an optical element sealing layer.
Further, in order to improve the connectivity with the optical element sealing layer 178 made of solder, a metal layer may be formed on the side of the light emitting element 138 in contact with the optical element sealing layer. In this case, the periphery of the light emitting element 138 is surely sealed by the optical element sealing layer 178. Note that the metal layer may be formed by a method such as plating or vapor deposition.

Thus, in the IC chip mounting substrate of the present invention, the optical element sealing layer may be made of solder. Of course, also in this case, it is desirable that a gap is formed in a portion of the optical path for transmitting an optical signal that is in contact with the light emitting element (optical element).
In addition, when an optical element sealing layer made of solder is used, the periphery of the optical element can be surely hermetically shielded (air-tightly sealed). Gas (nitrogen, argon, etc.) may be enclosed, and it is particularly desirable to enclose a gas having a refractive index smaller than that of air (that is, 1.0 or less). This is because it is particularly suitable for condensing an optical signal with a microlens.

FIG. 2 is a cross-sectional view schematically showing another embodiment of the IC chip mounting substrate of the first embodiment.
As shown in FIG. 2, in the IC chip mounting substrate 220, the conductor circuit 224 and the insulating layer 222 are laminated on both surfaces of the substrate 221, and the conductor circuit between the substrate 221 and the insulating layer 222 are sandwiched. The conductor circuits are electrically connected by through holes 229 and via holes 227, respectively. A solder resist layer 234 is formed on the outermost layer.
In this IC chip mounting substrate 220, an optical signal transmission optical path 242 is provided so as to penetrate the substrate 221, the insulating layer 222, and the solder resist layer 234.

In the optical signal transmission optical path 242, a resin composition 247 is filled in a portion penetrating the substrate 221 and the insulating layer 222. The diameter of the portion that penetrates the solder resist layer 234 is smaller than the diameter of the portion that penetrates the substrate 221 and the insulating layer 222.
In addition, the resin composition may be filled in the part which penetrates the soldering resist layer of the optical path for optical signal transmission. In addition, a conductor layer may be formed around the resin composition.

On one surface of the IC chip mounting substrate 220, a four-channel light receiving element 239 is surface-mounted via a solder connection portion 244 so that each of the light receiving portions 239a to 239d faces the optical path for optical signal transmission 242. In addition, the IC chip 240 is surface-mounted via the solder connection portion 243.
Further, an optical element sealing layer 248 is formed on the solder resist layer 234 on one surface so as to be in contact with at least the outer periphery of each of the light receiving elements 239, and is in contact with the optical path for optical signal transmission of the light receiving elements 239. A void is formed in the portion. Accordingly, the optical element sealing layer 248 is not formed on the portion of the light receiving element 239 that is in contact with the optical signal transmission optical path.
By forming such an optical element sealing layer 248, dust or foreign matter does not enter the optical signal transmission optical path 242, and transmission of the optical signal is hindered by the dust or foreign matter. Nor.
Solder bumps 237 are formed on the solder resist layer 234 on the other surface of the IC chip mounting substrate 220.

Therefore, an output signal from the four-channel light receiving element 239 can be transmitted through the optical signal transmission optical path 242. Here, the optical path for optical signal transmission 242 has a size capable of transmitting optical signals for four channels, and is collectively formed so as to penetrate the substrate 221, the insulating layer 222, and the solder resist layer 234.

In each of the end portions of the resin composition 247 on the side on which the light receiving element 239 is mounted and the opposite side of the optical signal transmission optical path 242, which passes through the solder resist layer 234, four pieces are provided. Microlens lenses 249a to 249d and 246a to 246d are disposed. Here, each of the micro lenses 249a to 249d and 246a to 246d is disposed at a position corresponding to each channel 239a to 239d of the light receiving element 239.
Accordingly, the optical signal to the light receiving element 239 passes through the microlenses 246 (246a to 246d) and 249 (249a to 249d), and thus the portion that penetrates the solder resist layer of the optical path for optical signal transmission 242. By disposing the microlens on the optical signal, transmission loss of the optical signal can be suppressed.

In the IC chip mounting substrate 220 having such a configuration, electrical signals transmitted through external optical components (such as optical fibers and optical waveguides) are transmitted through the microlenses 246a to 246d, the optical path 242 for transmitting optical signals, and the like. After being transmitted to the light receiving element 239 (light receiving part 239a) through the microlenses 249a to 249d and converted into an electric signal by the light receiving element 239, the IC is passed through the solder connection part 243, the conductor circuit 224, the via hole 227, and the like. It is sent to the chip 240 and processed.

In the IC chip mounting substrate 220, solder bumps 237 are formed on the solder resist layer 234 via a metal plating layer. Therefore, electrical signal transmission between the IC chip 240 and an external substrate is performed by soldering. It can also be performed via the bump 237.
When the solder bumps are formed in this way, the IC chip mounting substrate can be connected to an external substrate such as a motherboard substrate via the solder bumps. In this case, the self-alignment of the solder By the action, the IC chip mounting substrate can be arranged at a predetermined position.

As described above, in the case where a microlens is disposed on an IC chip mounting substrate on which a multichannel array element is mounted as an optical element, the diameter of the microlens depends on the pitch between the channels in the array element. What is necessary is just to determine suitably, for example, when using a 250 micrometer pitch array element, 100-240 micrometers is desirable and 180-230 micrometers is more desirable. If it is less than 100 μm, a desired focal length may not be obtained. If it exceeds 240 μm, adjacent microlenses may come into contact with each other, and the microlens may not be disposed at a predetermined position.
Further, for example, when an array element having a pitch of 500 μm is used, 100 to 490 μm is desirable, and 180 to 480 μm is more desirable. If it is less than 100 μm, a desired focal length may not be obtained. If it exceeds 490 μm, adjacent microlenses may come into contact with each other, and the microlens may not be disposed at a predetermined position.

In addition, as the shape of the optical path for optical signal transmission of the collective through hole structure, both the part that penetrates the substrate and insulating layer of the optical path for optical signal transmission, and the part that penetrates the solder resist layer of the optical path for optical signal transmission, For example, a cylinder, a prism, an elliptic cylinder, a shape in which a plurality of cylinders are arranged in parallel and a part of the side surfaces of the cylinders adjacent to each other are connected, and a columnar body having a bottom surface surrounded by a straight line and an arc. In addition, the part which penetrates the said board | substrate or an insulating layer, and the part which penetrates the said soldering resist layer do not necessarily need to have the same shape.

Moreover, the shape of the longitudinal cross-section of the part which penetrates the soldering resist layer of the optical path for optical signal transmission may be trapezoid shape by which a board | substrate and an insulating layer side become a short side depending on the case. In this case, the length of the short side is the diameter of the cross section of the portion that penetrates the solder resist layer.

Further, in the IC chip mounting substrate of the first embodiment, the optical signal transmission optical path of the collective through optical structure is formed in the portion that penetrates the substrate and the insulating layer, and the portion that penetrates the solder resist layer is the light receiving element. The optical signal transmission optical path may be formed only in the portion corresponding to the light receiving portion, or the optical signal transmission optical path having a collective penetrating optical structure may be formed in the portion penetrating the solder resist layer.

In addition, when the shape of the optical path for transmitting an optical signal is a shape in which a plurality of cylinders are arranged in parallel and part of the side surfaces of the cylinders adjacent to each other are connected, A dummy cylinder that does not function as an optical path for signal transmission may be formed.

The size of the optical signal transmission optical path having a collective through-hole structure as shown in FIG. 2 is preferably 100 μm to 5 mm in both the vertical and horizontal directions. Moreover, when the shape of the optical path for transmitting an optical signal is a cylinder, it is desirable that the diameter is in the above range.
If the diameter of the cross section is less than 100 μm, the transmission of the optical signal may be hindered. On the other hand, if the diameter exceeds 5 mm, the transmission loss of the optical signal is not improved, and the IC chip mounting substrate is downsized. Becomes difficult.

In the optical signal transmission optical path that passes through the substrate, the insulating layer, and the solder resist layer, the diameter of the cross section of the portion that passes through the substrate and the insulating layer is the same as the diameter of the cross section of the portion that passes through the solder resist layer. There may be.

Next, an IC chip mounting substrate having an optical signal transmission optical path having an individual through hole shape will be described. FIG. 3 is a cross-sectional view schematically showing another embodiment of the IC chip mounting substrate of the first invention.
The IC chip mounting substrate shown in FIG. 3, that is, the IC chip mounting substrate of the embodiment having an optical signal transmission optical path having an individual through-hole structure, is compared with the IC chip mounting substrate of the embodiment shown in FIG. The configuration is the same except that the shape of the optical path for optical signal transmission is different. Therefore, only the shape of the optical path for transmitting an optical signal will be described in detail here.

As shown in FIG. 3, in the IC chip mounting substrate 320, four independent optical signal transmission optical paths 342 (342a to 342d) are provided so as to penetrate the substrate 321, the insulating layer 322, and the solder resist layer 334. Yes.
In the optical signal transmission optical paths 342a to 342d, a resin composition 347 is filled in a portion penetrating the substrate 321 and the insulating layer 322.
The diameter of the cross section of the portion that penetrates the solder resist layer 234 is the same as the diameter of the cross section of the portion that penetrates the substrate 321 and the insulating layer 322. In addition, the diameter of the part which penetrates a soldering resist layer may be smaller than the diameter of the part which penetrates a board | substrate and an insulating layer.

On one surface of the IC chip mounting substrate 320, a four-channel light receiving element 339 is interposed via the solder connection portion 344 so that the light receiving portions 339 a to 339 d face the optical paths 342 a to 342 d for optical signal transmission. It is surface mounted. A gap is formed in a portion of the light receiving element 339 that is in contact with the optical signal transmission optical path.
Therefore, an output signal to the four-channel light receiving element 339 can be transmitted via any one of the optical signal transmission optical paths 342a to 342d. Here, each optical signal transmission optical path is formed independently so as to be able to transmit optical signals from the respective light receiving portions 339a to 339d included in the four-channel light receiving elements.
In addition, the resin composition may be filled in the part which penetrates the soldering resist layer of the optical path for optical signal transmission. In addition, a conductor layer may be formed around the portion of the optical signal transmission optical paths 342a to 342d that penetrates the substrate 321 and the insulating layer 322.

Further, the end portions of the resin composition 347 on the side where the light receiving element 339 is mounted and the opposite side of the optical paths 342a to 342d for optical signal transmission, and the portions penetrating the solder resist layer 334 are respectively provided. Microlenses 349 (349a to 349d) and 346 (346a to 346d) are disposed.
Therefore, the optical signal to the light receiving element 339 passes through the micro lenses 349a to 349d and 346a to 346d. As described above, by arranging the microlenses 349a to 349d and 346a to 346d at both ends of the optical paths for optical signal transmission 342a to 342d, transmission loss of the optical signal can be suppressed.

Regarding the diameter of the cross section of each optical signal transmission optical path, it is desirable that the lower limit of the portion of the optical signal transmission optical path that passes through the substrate and the insulating layer is 150 μm and the upper limit is 450 μm. Specifically, when an array element with a pitch of 250 μm is used, 150 to 200 μm is desirable, and when an array element with a pitch of 500 μm is used, 150 to 450 μm is desirable.

The reason why the diameter of the cross section of the optical path for transmitting optical signals formed separately is preferably 150 μm or more is as follows.
That is, the optical path for transmitting an optical signal in the above form is formed by forming a through hole penetrating the substrate and the insulating layer and then filling the through hole with a resin composition as necessary. This is because the through hole is usually formed using a drill, and when the through hole is formed by drilling, it is difficult to form a through hole having a diameter of less than 150 μm.

On the other hand, when the diameter of the cross section of the optical signal transmission optical path passing through the solder resist layer is smaller than the diameter of the cross section passing through the substrate or insulating layer, the size is 20 to 390 μm smaller. Is desirable, and it is more desirable that it is 30-100 μm smaller.
The solder resist layer is cut off by exposure and development when forming the solder resist layer (the solder resist layer is not formed so as to cover the interface between the insulating layer and the resin composition, and the solder resist layer is formed outside the above interface). This is because the state in which the opening for the optical path is formed) does not occur.

The diameter of the section of the optical signal transmission optical path that penetrates the substrate and the insulating layer is, for example, the diameter of the section when the portion that penetrates the substrate and the insulating layer is cylindrical. In the case of a long diameter of the cross section, in the case of a square columnar shape or a polygonal column shape, the length of the longest portion of the cross section is referred to, and the optical signal transmission optical path extends from the incident end side to the output end side. When the diameter of the cross section is not constant, it means the diameter of the cross section on the incident end side.
In the present invention, the cross section of the optical path for optical signal transmission refers to a cross section in a direction parallel to the main surface of the IC chip mounting substrate, and the vertical cross section of the optical path for optical signal transmission is perpendicular to the main surface. A cross section in the direction.

The shape of the optical path for transmitting an optical signal may be a shape including a portion whose cross section continuously decreases from the incident end side of the optical signal toward the emitting end side.
Moreover, the shape of the partial vertical cross section which penetrates the soldering resist layer of the said optical path for optical signal transmission may be trapezoid shape by which the insulating layer side becomes a short side depending on the case.

Also in the IC chip mounting substrate 320 having such a configuration, electrical signals transmitted through external optical components (such as optical fibers and optical waveguides) are transmitted through the microlenses 349a to 349d, 346a to 346d, and the optical signals. After being transmitted to the light receiving element 339 (light receiving part 339a) via the transmission optical path 342 and converted into an electric signal by the light receiving element 339, the IC chip is passed through the solder connection part 343, the conductor circuit 324, the via hole 327, and the like. 340 to be processed.

In the IC chip mounting substrate according to the first aspect of the present invention, the light receiving element mounted at a position close to the IC chip performs optical / electrical signal conversion, so that the electric signal transmission distance is short and the signal transmission reliability is excellent. It is possible to cope with higher speed communication.

Also in the IC chip mounting substrate of such an embodiment, the diameter of the microlens disposed in the optical signal transmission optical path may be appropriately determined according to the pitch between each channel in the array element, for example, a pitch of 250 μm. In the case of using this array element, 100 to 190 μm is desirable.
Further, for example, when an array element having a pitch of 500 μm is used, 100 to 490 μm is desirable, and 180 to 480 μm is more desirable.
The diameter of the microlens is preferably the same as the diameter of the cross section of the portion that penetrates the solder resist layer of the optical path for transmitting an optical signal.

In addition, as the shape of each optical signal transmission optical path of the individual through hole structure, a part formed on a substrate or an insulating layer of the optical signal transmission optical path, and a part penetrating the solder resist layer of the optical signal transmission optical path Both include, for example, a cylinder, a prism, an elliptic cylinder, a columnar body having a bottom surface surrounded by straight lines and arcs, and the like. In addition, the part formed in the said board | substrate or an insulating layer and the part which penetrates the said soldering resist layer do not necessarily need to have the same shape.

The IC chip mounting substrate according to the first aspect of the present invention that has been described so far is one in which the substrate and the insulating layer are made of a resin material.
However, even when the substrate, the insulating layer, and the like are made of a material other than resin, such as glass or ceramic, the same effects as those of the first invention can be obtained.
That is, in the IC chip mounting substrate in which the optical element is mounted on the wiring board made of glass or ceramic and the optical element sealing layer is formed so as to be in contact with the outer periphery of the optical element. The same effect as the IC chip mounting substrate of the present invention can be obtained. Further, in the case of forming an optical element sealing layer in an IC chip mounting substrate using such a wiring board made of glass or ceramic, the optical element sealing layer may be made of solder. desirable.

Next, the manufacturing method of the IC chip mounting substrate according to the first aspect of the present invention will be described in the order of steps.
(1) Using an insulating substrate as a starting material, first, a conductor circuit is formed on the insulating substrate.
Examples of the insulating substrate include a glass epoxy substrate, a polyester substrate, a polyimide substrate, a bismaleimide-triazine (BT) resin substrate, a thermosetting polyphenylene ether substrate, a copper clad laminate, and an RCC substrate.
Further, a ceramic substrate such as an aluminum nitride substrate or a silicon substrate may be used.
The conductor circuit can be formed, for example, by forming a solid conductor layer on the surface of the insulating substrate by electroless plating or the like and then performing an etching process. Moreover, you may form by performing an etching process to a copper clad laminated board or a RCC board | substrate.

In addition, in the case where connection between conductor circuits sandwiching the insulating substrate is performed through holes, for example, after forming through holes for through holes on the insulating substrate using a drill or a laser, electroless plating is performed. Through-holes are formed by processing or the like. In addition, the diameter of the through hole for the through hole is usually 100 to 300 μm.
Further, when a through hole is formed, it is desirable to fill the through hole with a resin filler.

(2) Next, the surface of the conductor circuit is roughened as necessary.
Examples of the roughening treatment include blackening (oxidation) -reduction treatment, etching treatment using an etchant containing a cupric complex and an organic acid salt, and treatment by Cu—Ni—P needle-like alloy plating. Etc.
Here, when a roughened surface is formed, normally, the lower limit of the average roughness of the roughened surface is preferably 0.1 μm, and the upper limit is preferably 5 μm. Considering the adhesion between the conductor circuit and the insulating layer, the influence of the conductor circuit on the electric signal transmission capability, etc., the lower limit of the average roughness is more preferably 2 μm, and the upper limit is more preferably 4 μm.
The roughening process may be performed before the resin filler is filled in the through hole, and a roughened surface may be formed on the wall surface of the through hole. This is because the adhesion between the through hole and the resin filler is improved.

(3) Next, on a substrate on which a conductor circuit is formed, a thermosetting resin, a photosensitive resin, a resin in which a photosensitive group is added to a part of the thermosetting resin, or a resin including these and a thermoplastic resin An uncured resin layer made of a composite is formed, or a resin layer made of a thermoplastic resin is formed. For forming these resin layers, for example, a resin similar to the resin used for the substrate can be used.
The uncured resin layer can be formed by applying uncured resin with a roll coater, curtain coater, or the like, or thermocompression bonding an uncured (semi-cured) resin film.
Moreover, the resin layer which consists of said thermoplastic resin can be formed by thermocompression-bonding the resin molding shape | molded in the film form.

Among these, a method of thermocompression bonding an uncured (semi-cured) resin film is desirable, and the resin film can be crimped using, for example, a vacuum laminator or the like.
In addition, the pressure bonding conditions are not particularly limited, and may be appropriately selected in consideration of the composition of the resin film. Usually, the pressure is 0.25 to 1.0 MPa, the temperature is 40 to 70 ° C., the degree of vacuum is 13 to 1300 Pa, It is desirable to carry out under conditions of a time of about 10 to 120 seconds.

Examples of the thermosetting resin include epoxy resins, phenol resins, polyimide resins, polyester resins, bismaleimide resins, polyolefin resins, polyphenylene ether resins, polyphenylene resins, and fluorine resins.
Specific examples of the epoxy resin include, for example, novolak type epoxy resins such as phenol novolak type and cresol novolak type, dicyclopentadiene-modified alicyclic epoxy resins, and the like.

As said photosensitive resin, an acrylic resin etc. are mentioned, for example.
Examples of the resin in which a photosensitive group is added to a part of the thermosetting resin include, for example, those obtained by acrylate reaction of the thermosetting group of the thermosetting resin with methacrylic acid or acrylic acid. Can be mentioned.

Examples of the thermoplastic resin include phenoxy resin, polyether sulfone (PES), polysulfone (PSF), polyphenylene sulfone (PPS) polyphenylene sulfide (PPES), polyphenylene ether (PPE) polyetherimide (PI), and the like. It is done.

Further, the resin composite is particularly limited as long as it includes a thermosetting resin or a photosensitive resin (including a resin in which a photosensitive group is added to a part of the thermosetting resin) and a thermoplastic resin. However, specific combinations of the thermosetting resin and the thermoplastic resin include, for example, phenol resin / polyether sulfone, polyimide resin / polysulfone, epoxy resin / polyether sulfone, epoxy resin / phenoxy resin, and the like. . Specific examples of the combination of the photosensitive resin and the thermoplastic resin include an acrylic resin / phenoxy resin, and an epoxy resin / polyether sulfone in which a part of the epoxy group is acrylated.

In addition, the blending ratio of the thermosetting resin or the photosensitive resin and the thermoplastic resin in the resin composite is preferably thermosetting resin or photosensitive resin / thermoplastic resin = 95/5 to 50/50. This is because a high toughness value can be ensured without impairing heat resistance.

The resin layer may be composed of two or more different resin layers.
Specifically, for example, the lower layer is formed from a thermosetting resin or a resin composite of photosensitive resin / thermoplastic resin = 50/50, and the upper layer is a thermosetting resin or photosensitive resin / thermoplastic resin = 90/50. It is formed from 10 resin composites.
With such a configuration, it is possible to ensure excellent adhesion with the substrate and ease of formation when forming a via hole opening or the like in a later step.

Moreover, you may form the said resin layer using the resin composition for roughening surface formation.
The roughened surface-forming resin composition is, for example, an acid, an alkali, in an uncured heat-resistant resin matrix that is hardly soluble in a roughened liquid consisting of at least one selected from acids, alkalis and oxidizing agents. And a substance soluble in a roughening liquid comprising at least one selected from oxidizing agents.
As used herein, the terms “slightly soluble” and “soluble” refer to those having a relatively high dissolution rate as “soluble” for convenience when immersed in the same roughening solution for the same time. The slow one is called “slightly soluble” for convenience.

The heat-resistant resin matrix is preferably one that can retain the shape of the roughened surface when the roughened surface is formed on the insulating layer using the roughening liquid. For example, a thermosetting resin, a heat Examples thereof include plastic resins and composites thereof. Further, by using a photosensitive resin, a via hole opening can be formed in the insulating layer by exposure and development.

Examples of the thermosetting resin include an epoxy resin, a phenol resin, a polyimide resin, a polyolefin resin, and a fluororesin. Moreover, when sensitizing the said thermosetting resin, methacrylic acid, acrylic acid, etc. are used, and a thermosetting group is (meth) acrylated.

Examples of the epoxy resin include cresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, biphenol F type epoxy resin, naphthalene type epoxy resin, Examples thereof include cyclopentadiene type epoxy resins, epoxidized products of condensates of phenols and aromatic aldehydes having a phenolic hydroxyl group, triglycidyl isocyanurate, and alicyclic epoxy resins. These may be used alone or in combination of two or more. Thereby, it will be excellent in heat resistance.

Examples of the thermoplastic resin include phenoxy resin, polyether sulfone, polysulfone, polyphenylene sulfone, polyphenylene sulfide, polyphenyl ether, polyether imide, and the like. These may be used alone or in combination of two or more.

The substance soluble in the roughening liquid comprising at least one selected from the acid, alkali and oxidizing agent is preferably at least one selected from inorganic particles, resin particles and metal particles.

Examples of the inorganic particles include aluminum compounds such as alumina and aluminum hydroxide, calcium compounds such as calcium carbonate and calcium hydroxide, potassium compounds such as potassium carbonate, magnesium compounds such as magnesia, dolomite, basic magnesium carbonate, and talc. And silicon compounds such as silica and zeolite. These may be used alone or in combination of two or more.

Examples of the resin particles include those made of a thermosetting resin, a thermoplastic resin, and the like. When the resin particles are immersed in a roughening solution made of at least one selected from an acid, an alkali, and an oxidizing agent, the heat resistance It is not particularly limited as long as it has a faster dissolution rate than the resin matrix. Specifically, for example, amino resins (melamine resins, urea resins, guanamine resins, etc.), epoxy resins, phenol resins, phenoxy resins, polyimide resins, Examples include those made of polyphenylene resin, polyolefin resin, fluororesin, bismaleimide-triazine resin and the like. These may be used alone or in combination of two or more.
The resin particles must be previously cured. This is because if the resin is not cured, the resin particles will be dissolved in a solvent that dissolves the heat-resistant resin matrix.
Further, as the resin particles, rubber particles, liquid phase resin, liquid phase rubber, or the like may be used.

Examples of the metal particles include gold, silver, copper, tin, zinc, stainless steel, aluminum, nickel, iron, lead, and the like. These may be used alone or in combination of two or more.
In addition, the metal particles may be coated with a resin or the like in order to ensure insulation.

When two or more kinds of the above-mentioned soluble substances are used in combination, the combination of the two kinds of soluble substances to be mixed is preferably a combination of resin particles and inorganic particles. Both of them have low conductivity, so that the insulation of the insulating layer can be secured, and the thermal expansion can be easily adjusted with the hardly soluble resin, and the insulating layer made of the roughened surface forming resin composition is cracked. This is because no separation occurs between the insulating layer and the conductor circuit.

Examples of the acid used as the roughening solution include phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, and organic acids such as formic acid and acetic acid. Among these, it is desirable to use an organic acid. This is because when the roughening treatment is performed, the metal conductor layer exposed on the bottom surface of the via hole opening is hardly corroded.
As the oxidizing agent, for example, an aqueous solution of chromic acid, chromium sulfuric acid, alkaline permanganate (such as potassium permanganate), or the like is preferably used.
Moreover, as said alkali, aqueous solution, such as sodium hydroxide and potassium hydroxide, is desirable.

The average particle size of the soluble substance is desirably 10 μm or less.
Further, a relatively large coarse particle having an average particle diameter of 2 μm or less and a fine particle having a relatively small average particle diameter may be used in combination. That is, a soluble substance having an average particle diameter of 0.1 to 0.5 μm and a soluble substance having an average particle diameter of 1 to 2 μm are combined.

Thus, by combining coarse particles having a relatively large average particle diameter and fine particles having a relatively small average particle diameter, the dissolution residue of the thin film conductor layer is eliminated, and the amount of palladium catalyst under the plating resist is reduced. Furthermore, a shallow and complicated roughened surface can be formed.
Furthermore, by forming a complicated roughened surface, a practical peel strength can be maintained even if the roughened surface has small irregularities.
The coarse particles preferably have an average particle size of more than 0.8 μm and less than 2.0 μm, and the fine particles preferably have an average particle size of 0.1 to 0.8 μm.

(4) Next, in the case of forming an insulating layer using a thermosetting resin or a resin composite as the material, the uncured resin insulating layer is subjected to a curing treatment, and a via hole opening is formed, An insulating layer is used. In this step, through-holes for through holes may be formed as necessary.
The via hole opening is preferably formed by laser processing. Further, when a photosensitive resin is used as the material of the insulating layer, it may be formed by exposure and development processing.

When an insulating layer using a thermoplastic resin as a material is formed, a via hole opening is formed in the resin layer made of the thermoplastic resin to form an insulating layer. In this case, the via hole opening can be formed by performing laser treatment.
Further, when the through hole for the through hole is formed in this step, the through hole for the through hole may be formed by drilling, laser processing, or the like.

Examples of the laser used for the laser treatment include a carbon dioxide laser, an ultraviolet laser, and an excimer laser. Among these, an excimer laser and a short pulse carbon dioxide laser are desirable.

Among excimer lasers, it is desirable to use a hologram type excimer laser. The hologram method is a method of irradiating a target object with laser light through a hologram, a condensing lens, a laser mask, a transfer lens, and the like. By using this method, a large number of vias are applied to the resin film layer by one irradiation. Hole openings can be formed efficiently.

When using a carbon dioxide laser, the pulse interval is preferably 10 ⁻⁴ to 10 ⁻⁸ seconds. Moreover, it is desirable that the time for irradiating the laser for forming the opening is 10 to 500 μsec.
In addition, by irradiating laser light through an optical system lens and a mask, a large number of openings for via holes can be formed at one time. This is because laser light having the same intensity and the same irradiation intensity can be irradiated to a plurality of portions through the optical system lens and the mask.
After forming the via hole opening in this manner, desmear treatment may be performed as necessary.

(5) Next, a conductor circuit is formed on the surface of the insulating layer including the inner wall of the via hole opening.
In forming the conductor circuit, first, a thin film conductor layer is formed on the surface of the insulating layer.
The thin film conductor layer can be formed by a method such as electroless plating or sputtering.

Examples of the material for the thin film conductor layer include copper, nickel, tin, zinc, cobalt, thallium, lead, and the like.
Among these, those made of copper, copper and nickel are desirable from the viewpoint of excellent electrical characteristics, economical efficiency, and the like.
As for the thickness of the thin film conductor layer, when the thin film conductor layer is formed by electroless plating, the lower limit of the thickness is preferably 0.3 μm, and the upper limit is preferably 2.0 μm. More preferably, the lower limit is 0.6 μm and the upper limit is 1.2 μm. Moreover, when forming by sputtering, 0.1-1.0 micrometer is desirable.

Further, before forming the thin film conductor layer, a roughened surface may be formed on the surface of the insulating layer. By forming the roughened surface, the adhesion between the insulating layer and the thin film conductor layer can be improved. In particular, when an insulating layer is formed using a resin composition for forming a roughened surface, it is desirable to form a roughened surface using an acid, an oxidizing agent, or the like.

Further, when the through hole for the through hole is formed in the step (4), when the thin film conductor layer is formed on the insulating layer, the through hole is formed by forming the thin film conductor layer on the wall surface of the through hole. It is good.

(6) Next, a plating resist is formed on a part of the insulating layer having the thin film conductor layer formed on the surface thereof.
The plating resist can be formed, for example, by sticking a photosensitive dry film, placing a photomask made of a glass substrate or the like on which a plating resist pattern is drawn, and performing exposure and development processing.

(7) Thereafter, electrolytic plating is performed using the thin film conductor layer as a plating lead, and an electrolytic plating layer is formed in the plating resist non-forming portion. As the electrolytic plating, copper plating is desirable.
The thickness of the electrolytic plating layer is preferably 5 to 20 μm.

Then, a conductor circuit (including a via hole) can be formed by removing the plating resist and the thin film conductor layer under the plating resist.
The plating resist may be removed using, for example, an alkaline aqueous solution, and the thin film conductor layer may be removed using a mixed solution of sulfuric acid and hydrogen peroxide, sodium persulfate, ammonium persulfate, ferric chloride, chloride. What is necessary is just to perform using etching liquid, such as cupric.
Moreover, after forming the said conductor circuit, you may remove the catalyst on an insulating layer using an acid or an oxidizing agent as needed. This is because deterioration of electrical characteristics can be prevented.
Moreover, after forming this plating resist, it replaces with the method (process (6) and (7)) which forms an electroplating layer, forms an electroplating layer on the whole surface on a thin film conductor layer, and performs an etching process. A conductor circuit may be formed using a method.

Further, when a through hole is formed in the steps (4) and (5), a resin filler may be filled in the through hole.
Moreover, when the resin filler is filled in the through hole, a lid plating layer that covers the surface layer portion of the resin filler layer may be formed by performing electroless plating or the like, if necessary.

(8) Next, when a lid plating layer is formed, if necessary, the surface of the lid plating layer is roughened, and the steps (3) and (4) are repeated. An insulating layer is formed. In this step, a through hole may be formed or may not be formed.
(9) Furthermore, if necessary, the conductor circuit and the insulating layer may be laminated by repeating the steps (5) to (8).

By performing the steps (1) to (9), a multilayer wiring board in which a conductor circuit and an insulating layer are formed on both sides of the substrate can be manufactured.
The manufacturing method of the multilayer wiring board detailed here is a semi-additive method, but the manufacturing method of the multilayer wiring board is not limited to the semi-additive method, and is a full additive method, a subtractive method, a batch lamination method, a conformal method, etc. Can also be used.

(10) Next, an optical path for transmitting an optical signal that penetrates the multilayer wiring board is formed. The optical path for transmitting optical signals that penetrates the multilayer wiring board formed in this step is also referred to as an optical path through hole.
First, an optical path through hole is formed in a multilayer wiring board manufactured through the above-described steps.
The optical path through hole is formed by, for example, drilling or laser processing.
Examples of the laser used in the laser treatment include those similar to the laser used in forming the via hole opening.
In the drilling process, it is desirable to use an apparatus with a recognition function of a recognition mark that reads the recognition mark on the multilayer wiring board, corrects the machining position, and drills.
The formation position of the optical path through hole is not particularly limited, and may be appropriately selected in consideration of the design of the conductor circuit, the mounting position of the IC chip, the optical element, and the like.
The optical path through hole is desirably formed for each optical element such as a light receiving element or a light emitting element. Moreover, you may form for every signal wavelength.

In this step, when a plurality of cylinders are arranged in parallel and a through hole for an optical path having a shape in which a part of the side surfaces of adjacent cylinders are connected to each other, the number of cylinders to be formed is an odd number. In addition, it is desirable to first form a portion that becomes a column that is not adjacent to each other, and then to form a column in which a part of the side surface is connected between the columns that are not adjacent to each other.
If you try to continuously form adjacent cylinders that are partly connected, the tip of the drill will run away in the direction of the already formed cylinder, and the tip of the drill will run out, resulting in poor precision during drilling. Because there is.
In addition, the processing accuracy in the case of forming a cylinder in which a part of the side surface is connected between the cylinders that are not adjacent to each other, after first forming a portion that becomes a cylinder that is not adjacent, is about 40 μm, The processing accuracy in the case of continuously forming adjacent cylinders that are partially connected is about 10 μm.

Moreover, after forming the through hole for an optical path, a desmear process may be performed on the wall surface of the through hole for an optical path as necessary.
The desmear treatment can be performed using, for example, a treatment with a permanganic acid solution, a plasma treatment, a corona treatment, or the like. By performing the desmear process, resin residue, burrs, etc. in the optical path through-hole can be removed, and light resulting from irregular reflection of light on the wall surface of the optical signal transmission optical path completed through a subsequent process. Signal transmission loss can be reduced.

In addition, after forming the through hole for the optical path, before forming the conductor layer in the following process or filling the uncured resin composition, the wall surface of the through hole for the optical path is roughened as necessary. A roughened surface forming step may be performed. This is because the adhesion to the conductor layer and the resin composition can be improved.
The roughened surface is formed, for example, when an optical path through hole such as a substrate or an insulating layer is formed with an acid such as sulfuric acid, hydrochloric acid or nitric acid; an oxidizing agent such as chromic acid, chromium sulfuric acid or permanganate. It can be carried out by dissolving the exposed part. It can also be performed by plasma treatment, corona treatment, or the like.
The lower limit of the average roughness (Ra) of the roughened surface is desirably 0.5 μm, and the upper limit is desirably 5 μm. A more desirable lower limit of the average roughness (Ra) is 1 μm, and a more desirable upper limit is 3 μm. This is because within this range, the adhesiveness with the conductor layer and the resin composition is excellent, and the transmission of the optical signal is not adversely affected.

After the optical path through hole is formed, a conductor layer may be formed on the wall surface of the optical path through hole, if necessary.
The conductor layer can be formed by a method such as electroless plating, sputtering, or vacuum deposition.
Specifically, for example, after forming a through hole for an optical path, a catalyst nucleus is applied to the wall surface of the through hole for the optical path, and then the substrate on which the through hole for the optical path is formed is immersed in an electroless plating bath Etc. can be used.
Also, a conductor layer composed of two or more layers may be formed by combining electroless plating or sputtering, or a conductor layer composed of two or more layers may be formed by performing electroplating after electroless plating or sputtering. Good. Further, when the conductor layer is formed in this step, the conductor layer may be a glossy metal layer.

When forming such a conductor layer, it is desirable to form a conductor layer on the wall surface of the through hole for an optical path and to form an outermost layer conductor circuit on the outermost insulating layer of the multilayer wiring board. Specifically, for example, when a conductor layer is first formed on the wall surface of the through hole for an optical path by electroless plating or the like, the conductor layer is also formed on the entire surface of the insulating layer.

Next, a plating resist is formed on the conductor layer formed on the surface of the insulating layer. The plating resist may be formed, for example, by attaching a photosensitive dry film, then closely contacting a photomask made of a glass substrate or the like on which the plating resist pattern is drawn, and performing an exposure development process.

Furthermore, electrolytic plating is performed using the conductor layer formed on the insulating layer as a plating lead, and an electrolytic plating layer is formed on the plating resist non-forming portion, and then the plating resist and the conductor layer under the plating resist are removed. By doing so, an independent conductor circuit is formed on the outermost insulating layer.

Further, after forming the conductor layer, a roughened surface may be formed on the wall surface of the conductor layer. The roughened surface is formed by, for example, blackening (oxidation) -reduction treatment, etching treatment using an etchant containing a cupric complex and an organic acid salt, or treatment by Cu-Ni-P needle-shaped alloy plating. Etc. can be used.

(11) Next, if necessary, the resin composition is filled into the through hole for an optical path that penetrates the multilayer wiring board formed in the step (10).
In the optical path for optical signal transmission that is completed through a post-process by filling the uncured resin composition in the through hole for the optical path and then performing a curing process, the portion formed on the substrate or the insulating layer is a resin. It will be filled with the composition.
A specific filling method of the uncured resin composition is not particularly limited, and for example, a method such as printing or potting can be used.
When filling the uncured resin composition by printing, the uncured resin composition may be printed once, or may be printed twice or more. Moreover, when filling the resin composition in the through-hole for optical paths, you may print from both surfaces of a multilayer wiring board.

In addition, when filling the uncured resin composition, the uncured resin composition was filled in an amount slightly larger than the inner product of the optical path through hole, and overflowed from the optical path through hole after the filling was completed. Excess resin composition may be removed.
The excess resin composition can be removed by, for example, polishing. Further, when removing the excess resin composition, the state of the resin composition may be a semi-cured state or a completely cured state, which is appropriately determined in consideration of the material of the resin composition and the like. Just choose.

By passing through such a through-hole forming step and a roughened surface forming step, a conductor layer forming step, and a resin composition filling step performed as necessary, the resin composition is added to the multilayer wiring board as necessary. A part of the filled optical path for transmitting an optical signal can be formed.
Moreover, when performing the said conductor layer formation process, an independent conductor circuit can be formed by forming a conductor layer also on the surface of an insulating layer and performing the process mentioned above. Of course, even when the conductor layer forming step is not performed, the conductor circuit can be formed on the surface of the insulating layer by the method described above.

Further, in this step, it is desirable to polish the exposed surface of the resin composition exposed from the optical path through hole, and to flatten the exposed surface. This is because by flattening the exposed surface, there is less possibility that transmission of an optical signal will be hindered.
The polishing treatment can be performed by, for example, buffing, polishing with sandpaper, mirror polishing, clean polishing, lapping, or the like. Further, chemical polishing using an acid, an oxidizing agent, a chemical solution, or the like may be performed. Moreover, you may perform a grinding | polishing process combining 2 or more types of these methods.

(12) Next, if necessary, a solder resist layer forming step of forming a solder resist layer having an optical path opening communicating with the optical path through hole is performed.
Specifically, for example, the solder resist layer can be formed by performing the following steps (a) and (b).

(A) First, a solder resist composition layer is formed on the outermost layer of the multilayer wiring board in which the through hole for the optical path is formed.
The layer of the solder resist composition can be formed using, for example, a solder resist composition made of polyphenylene ether resin, polyolefin resin, fluororesin, thermoplastic elastomer, epoxy resin, polyimide resin or the like.

Examples of solder resist compositions other than those described above include, for example, (meth) acrylates of novolak epoxy resins, imidazole curing agents, bifunctional (meth) acrylic acid ester monomers, and (meth) acrylic acid having a molecular weight of about 500 to 5,000. Examples include paste polymers containing ester polymers, thermosetting resins composed of bisphenol-type epoxy resins, photosensitive monomers such as polyvalent acrylic monomers, glycol ether solvents, and the viscosity at 25 ° C. It is desirable that the pressure is adjusted to 1 to 10 Pa · s. A commercially available solder resist composition can also be used.
Moreover, you may press-bond the film which consists of the said soldering resist composition, and may form the layer of a soldering resist composition.

(B) Next, an opening having a diameter smaller than the diameter of the cross section of the optical path through hole or the like (hereinafter also referred to as an optical path opening) is connected to the layer of the solder resist composition. Form. Specifically, for example, it can be formed by exposure development processing, laser processing, or the like.

When the diameter of the cross section of the portion that penetrates the solder resist layer of the optical path for optical signal transmission is made smaller than the diameter of the cross section of the portion that penetrates the substrate or insulating layer of the optical signal transmission optical path, The diameter is desirably 20 to 390 μm smaller than the diameter of the cross section of the optical path through hole, and more desirably 30 to 100 μm.

Further, when forming the optical path opening, it is desirable to simultaneously form a solder bump forming opening (an opening for mounting an IC chip or an optical element). The formation of the optical path opening and the formation of the solder bump forming opening may be performed separately.
Also, when forming the solder resist layer, a solder resist layer having an opening for an optical path and an opening for forming a solder bump is prepared by preparing a resin film having an opening at a desired position in advance and pasting the resin film. May be formed.

Through the steps (a) and (b), an optical path opening communicating with the optical path through hole can be formed on the multilayer wiring board in which the optical path through hole is formed.

Further, the optical path opening formed in the solder resist layer may be filled with an uncured resin composition in the same manner as the optical path through hole.
In some cases, a conductor layer may also be formed on the wall surface of the optical path opening formed in the solder resist layer.

Further, in this step, after forming the solder resist layer, the microlens is disposed in the end of the resin composition filled in the through hole for the optical path, and in the opening for the optical path formed in the solder resist layer. Also good.
Further, when the microlens is provided, a surface treatment may be performed in advance on a portion where the microlens is provided.
Depending on the wettability of the part where the microlenses are disposed, the shape of the microlens, in particular, the sag height is likely to vary, but the surface treatment can suppress the sag height variation. it can.

Examples of the surface treatment include treatment with a water-repellent coating material such as a fluorine-based polymer coating agent (surface tension 10 to 12 mN / m), water-repellent treatment with CF ₄ plasma, and hydrophilic treatment with O ₂ plasma.

Moreover, when arrange | positioning the said micro lens, you may arrange | position directly on the said resin composition, and may arrange | position through an adhesive layer.
As a method of directly disposing the microlens on the resin composition, for example, an appropriate amount of uncured optical lens resin is dropped on the resin composition, and the uncured optical lens resin is cured. The method of giving is mentioned.
In the above method, when an appropriate amount of uncured optical lens resin is dropped onto the resin composition, an apparatus such as a dispenser, an inkjet, a micropipette, or a microsyringe can be used. Further, the uncured resin for an optical lens dropped on the resin composition using such an apparatus tends to be spherical due to the surface tension, and thus becomes hemispherical on the resin composition, and then hemispherical. A hemispherical microlens can be formed on the resin composition by curing the uncured optical lens resin.
In addition, the diameter of the microlens formed in this way, the shape of the curved surface, etc., the viscosity of the uncured optical lens resin, etc., as appropriate, considering the wettability between the resin composition and the uncured optical lens resin It can be controlled by adjusting.

(13) Next, an optical element is mounted using the following method, and further, solder pads and solder bumps are formed. That is, the conductor circuit portion exposed by forming the opening for forming the solder bump is coated with a corrosion-resistant metal such as nickel, palladium, gold, silver, platinum, or the like as necessary to form a solder pad. In these, it is desirable to form a coating layer with metals, such as nickel-gold, nickel-silver, nickel-palladium, nickel-palladium-gold.
The coating layer can be formed by, for example, plating, vapor deposition, electrodeposition, or the like. Among these, it is desirable to form by plating from the viewpoint that the uniformity of the coating layer is excellent. The formation of the solder pad may be performed before the microlens placement step.

Further, a solder bump is formed by reflowing after filling the solder pad with a solder paste through a mask in which an opening is formed in a portion corresponding to the solder pad. Further, gold bumps may be formed instead of the solder bumps.
Furthermore, an optical element (light receiving element and light emitting element) is mounted on the solder resist layer. The optical element can be mounted, for example, via the solder bump. Further, for example, when forming the solder bump, the optical element may be mounted at the time when the solder paste is filled, and the optical element may be mounted simultaneously with the reflow. Further, the composition of the solder used here is not particularly limited, and any composition such as Sn / Pb, Sn / Pb / Ag, Sn / Ag / Cu, Sn / Cu may be used.
Further, the optical element may be mounted using a conductive adhesive or the like instead of the solder.
In addition, a microlens may be formed in advance on the optical element to be mounted in this step.

(14) Next, an optical element sealing layer is formed in contact with the periphery of the optical element.
The optical element sealing layer can be formed, for example, by potting an ineffective resin composition and then performing a curing process.
When the optical element sealing layer is formed by potting, the optical element sealing layer may be formed so as to cover the optical element as long as the optical element sealing layer is formed in contact with the outer periphery of the optical element.
Through such steps, the IC chip mounting substrate of the first aspect of the present invention can be manufactured.

Next, an IC chip mounting substrate according to the second aspect of the present invention will be described.
The IC chip mounting substrate of the second aspect of the present invention is an IC chip mounting substrate in which a conductor circuit and an insulating layer are laminated on both surfaces of the substrate, an optical element is mounted, and an optical path for transmitting an optical signal is formed. Because
A cap member is attached so as to cover at least the optical element.

In the IC chip mounting substrate of the second aspect of the present invention, since the cap member is attached so as to cover at least the optical element, there is no gap open to the outside between the optical element and the optical element mounting surface. Therefore, dust and foreign matter do not enter the optical path for optical signal transmission, and therefore transmission of the optical signal is not hindered due to the presence of dust or the like.
Therefore, the IC chip mounting substrate of the second aspect of the present invention is excellent in reliability.

Since the IC chip mounting substrate according to the second aspect of the present invention functions as a so-called package substrate, the conductor circuit is basically formed with a fine pattern, so that the size can be reduced and the yield can be improved. .
Further, since the optical element is mounted and the optical path for transmitting the optical signal is formed, the input / output signals of the optical element can be transmitted through the optical path for transmitting the optical signal. Further, when an IC chip is mounted on the IC chip mounting substrate, the distance between the IC chip and the optical element is short, and the electrical signal transmission reliability is excellent.

In addition, the IC chip mounting substrate of the second aspect of the present invention usually has a solder resist layer formed on the outermost layer of the substrate on which the conductor circuit and the insulating layer are laminated. Therefore, the IC chip mounting substrate according to the embodiment in which the solder resist layer is formed as the outermost layer will be described below. Note that the solder resist layer is not necessarily formed.

The IC chip mounting substrate according to the second aspect of the present invention has a cap so as to cover the entire optical element, instead of forming the optical element sealing layer, as compared with the IC chip mounting substrate according to the first aspect of the present invention. Although different from the IC chip mounting substrate of the first invention in that the members are attached, other configurations are the same as the IC chip mounting substrate of the first invention. Therefore, only the cap member will be described in detail here.

FIG. 4 is a cross-sectional view schematically illustrating an embodiment of an IC chip mounting substrate according to the second aspect of the present invention. FIG. 4 shows the IC chip mounting substrate on which the IC chip is mounted.
As shown in FIG. 4, in the IC chip mounting substrate 420 of the second aspect of the present invention, the light receiving portion 439a and the light emitting portion 438a are disposed on one surface so that each of the light receiving portion 439a faces the optical signal transmission optical path 442. The element 439 and the light emitting element 438 are surface-mounted via a solder connection portion 444, and the IC chip 440 is further surface-mounted via a solder connection portion 443.
On the solder resist layer 434 on one surface, a cap member 418 is attached via an adhesive 419 so as to cover the light emitting element 438 and the light receiving element 439.
By attaching such a cap member 418, dust or foreign matter does not enter the optical signal transmission optical path 442, and transmission of the optical signal is not hindered by the dust or foreign matter.
The configuration of the IC chip mounting substrate shown in FIG. 4 is the same as that shown in FIG. 1 except that the optical element sealing layer is not formed and the cap member is attached as described above. This is substantially the same as the IC chip mounting substrate.
However, the IC chip mounting substrate 420 shown in FIG. 4 is provided with microlenses in the light receiving part and the light emitting part of the light receiving element 439 and the light emitting element 438, respectively, and the solder resist layer of the optical path for optical signal transmission is provided. The difference is that no microlens is disposed in the penetrating portion.
In this regard, as already described in the first aspect of the present invention, a microlens may be disposed in a portion penetrating the solder resist layer of the optical path for transmitting an optical signal, and the mounted light receiving device. A microlens may be disposed in the light receiving portion of the element or the light emitting portion of the light emitting element. In some cases, the microlens may be disposed in both, or the microlens may not be disposed. Good.

The material, shape, and the like of the cap member are not particularly limited, and examples of the material include ceramic, resin, metal, glass, and the like, among which resin is desirable. Moreover, the shape of a cap member should just be a shape which can cover the said optical elements, such as a U-shaped cross section. Specific examples include a ceramic cap with a sealant and a resin cap with an adhesive.
Note that the resin cap member can be manufactured by subjecting a plate-shaped material substrate to a counterbore process and then a dicing process. Further, metal plating (Ni / Au plating) may be applied to the outer upper surface of the cap member. This is because reliability can be improved.

In the IC chip mounting substrate shown in FIG. 4, the cap member is attached to the solder resist layer via an adhesive (resin). In the IC chip mounting substrate of the second aspect of the present invention, the cap member is The solder resist layer may be attached to a portion where the solder resist layer is not formed via solder. However, when a cap member is attached via solder, a pad is required on the outermost layer, which places restrictions on the design of the conductor circuit, and additionally requires a separate solder shield process. The cap member is desirably attached via an adhesive (resin). In addition, also when attaching a cap member via an adhesive agent (resin), the reliability equivalent to the case where it attaches via solder can be acquired.

Further, in the IC chip mounting substrate shown in FIG. 4, the cap member is attached so as to cover each of the mounted optical elements separately, but in the IC chip mounting substrate of the second invention, Embodiment which attached the cap member is not limited to such a form.

FIG. 5 is a sectional view schematically showing another embodiment of the IC chip mounting substrate of the second invention.
As shown in FIG. 5, a cap member 518 that can cover the light receiving element 539 and the IC chip 540 in a lump is attached to the IC chip mounting substrate 520. In an IC chip mounting substrate on which an optical element is mounted, it is necessary to shorten the distance between the optical element and the IC chip as the signal transmission speed increases, and a cap member is disposed between the optical element and the IC chip. Since there is no space, it may be desirable to attach a cap member that collectively covers the light receiving element and the IC chip.
Further, a cap member may be attached so as to cover the surface-mounted components such as resistors and capacitors together with the optical element.
The configuration of the IC chip mounting substrate 520 is the same as that shown in FIG. 5 except that a cap member 518 capable of covering the light receiving element 539 and the IC chip 540 at once is attached without forming the optical element sealing layer. This is substantially the same as the IC chip mounting substrate 120 shown in FIG.
However, the IC chip mounting substrate 520 shown in FIG. 5 is provided with microlenses in the light receiving portion and the light emitting portion of the light receiving element 539 and the light emitting element 538, respectively. The difference is that no microlens is disposed in the penetrating portion.

Further, in the IC chip mounting substrate shown in FIG. 5, heat sink portions 519a and 519b for dissipating heat of the optical element and the IC chip are provided in the cap member 518. IC chips and optical elements generate heat when they are driven. In particular, the IC chip generates a large amount of heat, and the heat from the IC chip shortens the life of the optical elements mounted in the vicinity, or the optical elements become inoperable. However, by providing the heat sink portion inside the cap member, such inconvenience can be avoided more reliably.

The cap member provided with the heat sink part is not particularly limited as long as it can dissipate heat from an IC chip or the like, and as shown in FIG. 5, heat sink parts 519a and 519b are provided inside the cap member 518. The cap member may be made of metal or ceramic, and the cap member itself may function as a heat sink part. Further, when the cap member is made of a resin, a member in which a heat sink portion made of metal, ceramic or the like is formed can be used. That is, the heat sink part may be formed separately from the cap member, or may be formed integrally with the cap member.
When the cap member is made of ceramic, it is desirable that the material has excellent thermal conductivity such as alumina or aluminum nitride.

The shape of the heat sink portion may be any shape such as a quadrangular prism.
In addition, the cap member provided with the heat sink part is coated with an adhesive or resin having excellent thermal conductivity on the surface of the IC chip or optical element, and the heat of the IC chip or the like is transferred from the heat sink part via the adhesive or the like. It only has to be attached so that heat can be dissipated.

The IC chip mounting substrate according to the second aspect of the present invention is not limited to the form shown in FIGS. 4 and 5, and a cap member having a shape integrally covering a plurality of optical elements is attached. Alternatively, a cap member having a shape that integrally covers the plurality of optical elements and the IC chip may be attached.

Further, in the IC chip mounting substrate of the second aspect of the present invention, as in the IC chip mounting substrate of the first aspect of the present invention, a gap is formed in the portion of the optical signal transmission optical path that is in contact with the optical element. It is desirable that
In the second IC chip mounting substrate, the optical element mounted on the outermost layer is preferably a light receiving element and / or a light emitting element, as in the IC chip mounting substrate of the first aspect of the present invention.

As described above, the IC chip mounting substrate of the second invention is the same as the IC chip mounting substrate of the first invention except that a cap member is attached instead of the optical element sealing layer. It has a configuration. Therefore, in the IC chip mounting substrate of the second aspect of the present invention, a multi-channel optical element may be mounted as an optical element, and an optical signal transmission optical path having a collective through-hole structure or an optical signal having an individual through-hole structure. A transmission optical path may be formed, or a microlens may be formed.

In addition, when the surface mount component to which the optical element or other cap member is attached is of the wire bonding type, the optical element or the like is protected by attaching the cap member. It is not necessary to seal, but when wire bonding is unsealed, it is difficult to handle until the cap member is attached. Therefore, it is desirable to seal the wire bonding.

Next, a method for manufacturing the IC chip mounting substrate of the second aspect of the present invention will be described.
In the step (14) of producing the IC chip mounting substrate of the first invention, without forming the optical element sealing layer, the following method is used to cover the optical element mounted on the outermost layer. Except for attaching the cap member, the IC chip mounting substrate according to the first aspect of the present invention can be manufactured using a method substantially similar to the method for manufacturing the substrate.

As a method of attaching the cap member so as to cover the optical element, for example, an uncured resin composition is applied in advance to a predetermined portion of the cap member or a predetermined portion of the solder resist layer, and then the cap member is placed. Further, the cap member is temporarily fixed by curing the uncured resin composition up to the B stage, and then a weight is placed on the cap member or the cap member is fixed with a jig such as a clip. The cap member can be attached by applying a load of 1 to 1000 g / cm ² and curing the resin composition in an oven in this state.
In addition, after pasting a B-stage resin film on a predetermined part of the cap member or a predetermined part of the solder resist layer in advance, the cap member is placed, and then the resin film is cured by applying heat to the cap member. Then, a load of 1 to 1000 g / cm ² is applied by placing a weight on the cap member or fixing the cap member with a jig such as a clip. In this state, the resin film is cured in an oven. The cap member can also be attached by performing the above.
In addition, a solder paste is applied in advance to a predetermined portion of the cap member or a predetermined portion on the outermost insulating layer, the cap member is disposed at a predetermined position, and the cap member is attached by performing a reflow process. A method can also be used.

Further, when the cap member is attached using such a method, the cap member may be attached so as to cover only one optical element, or the cap member may be integrally covered with a plurality of optical elements. In some cases, a cap member may be attached so as to integrally cover one or a plurality of optical elements and a surface mounting component such as an IC chip.

Moreover, the adhesive used when attaching the cap member is desirably an adhesive that does not spread during curing from the viewpoint of reliability. Accordingly, it is desirable to use a resin composition having the same characteristics as the resin used when forming the optical element sealing layer in the IC chip mounting substrate of the first aspect of the present invention.

In the manufacture of the IC chip mounting substrate according to the second aspect of the present invention, when various surface mount components are mounted inside the cap member via the solder bumps, after the surface mount components are mounted, the flux cleaning is performed. It is desirable to do. If the flux mounting is not performed after mounting the surface mount component, the flux component solidifies and peels off after manufacturing the IC chip mounting substrate, and enters the optical path for transmitting the optical signal as a foreign substance. This is because the transmission loss may increase or the optical signal may not be transmitted.
By using such a method, the IC chip mounting substrate of the second aspect of the present invention can be manufactured.

The IC chip mounting substrate according to the second aspect of the present invention that has been described so far is one in which the substrate and the insulating layer are made of a resin material.
However, even when the substrate, the insulating layer, and the like are made of a material other than resin, such as glass or ceramic, the same effects as those of the second invention can be obtained.
That is, the above-described IC of the second invention is also applied to an IC chip mounting substrate in which an optical element is mounted on a wiring board made of glass or ceramic and a cap member is attached so as to cover at least the optical element. The same effect as the chip mounting substrate can be obtained.

Next, an optical communication device according to the third aspect of the present invention will be described.
The optical communication device according to the third aspect of the present invention is a motherboard substrate in which a conductor circuit and an insulating layer are laminated on at least one surface of the substrate, an optical waveguide is formed, and an optical path for transmitting an optical signal is further formed. And an optical communication device on which an IC chip mounting substrate on which an optical element is mounted is mounted.
An IC chip mounting substrate sealing layer is formed in contact with the outer periphery of the IC chip mounting substrate.

In the optical communication device of the third aspect of the present invention, since the IC chip mounting substrate sealing layer is formed so as to be in contact with the outer periphery of the IC chip mounting substrate, the IC chip mounting substrate and the IC chip mounting substrate There is no gap open to the outside between the surface on which the board is mounted and dust or foreign matter does not enter the optical path for optical signal transmission.Therefore, due to the presence of this dust, Transmission of optical signals is not hindered.
Therefore, the optical communication device of the third aspect of the present invention is excellent in reliability.

In the optical communication device according to the third aspect of the present invention, since electronic components and optical elements necessary for optical communication can be mounted and integrated on a motherboard substrate, the optical communication terminal device can be made thinner and smaller. It can contribute to the conversion.

In the optical communication device of the third aspect of the present invention, the IC chip mounting substrate is mounted on the motherboard.
Examples of the IC chip mounting substrate include the above-described IC chip mounting substrate of the first invention and the IC chip mounting substrate of the second invention described above. In addition to these IC chip mounting substrates, for example, an IC chip mounting substrate having a concave-shaped optical signal transmission optical path (to be described later) (hereinafter also referred to as the IC chip mounting substrate of the third embodiment). Etc.

The IC chip mounting substrate of the third embodiment will be described.
FIG. 6 is a cross-sectional view schematically showing an example of an IC chip mounting substrate according to the third embodiment. In the IC chip mounting substrate 620 of the third embodiment shown in FIG. 6, the conductor circuit 624 and the insulating layer 622 are laminated on both surfaces of the substrate 621, and between the conductor circuits sandwiching the substrate 621 and the insulating layer 622. The conductor circuits sandwiching between are electrically connected through through holes 629 or via holes 627. A solder resist layer 634 is formed on the outermost layer.
Further, a concave-shaped optical signal transmission optical path 642 is formed on the IC chip mounting substrate 620. In this optical signal transmission optical path 642, each of the four-channel light receiving element 639 and the IC chip 640 is mounted by wire bonding 648. Further, a resin composition is formed in a part of the optical signal transmission optical path 642. Object 647 is filled.
A solder bump 637 is formed on the solder resist layer 634 on the side where the concave optical signal transmission optical path is formed.
The IC chip may be mounted on the surface opposite to the side on which the optical path for transmitting optical signals is formed.

Therefore, an input signal to the four-channel light receiving element 639 is transmitted through the optical signal transmission optical path 642. Here, the optical signal transmission optical path 642 has a size capable of transmitting optical signals for four channels, and is formed in a concave shape in part of the insulating layer 623 and the solder resist layer 634.

Further, four microlenses 646a to 646d are disposed at the end of the resin composition 647 on the side opposite to the side on which the light receiving element 639 is mounted in the optical path for transmitting optical signals 642. Here, each of the micro lenses 646a to 646d is individually disposed at a position corresponding to each channel 639a to 639d of the light receiving element 639.
Accordingly, the optical signal to the light receiving element 639 passes through the microlenses 646a to 646d. As described above, by arranging the microlenses 646a to 646d in the optical path 642 for transmitting an optical signal, transmission loss of the optical signal can be suppressed. In addition, in the IC chip mounting substrate of the third embodiment, the microlens may be disposed as necessary, and the portion that penetrates the solder resist layer of the optical path for transmitting optical signals is filled with the resin composition. It may be formed by a gap.
Here, as shown in FIG. 6, the size of the opening in a plan view of the portion that penetrates the solder resist layer of the optical path for optical signal transmission and the portion formed in the insulating layer is as follows. The penetrating part may be larger, the both may be the same, or the part formed in the insulating layer may be larger. In this case, a formation layer (lens marker) for arranging the microlens may be prepared.

Hereinafter, the formation layer will be briefly described.
When preparing the formation layer, prior to disposing the microlens, a resin layer for forming the formation layer is formed by applying a resin for forming a microlens to the periphery including a portion where the microlens is formed, Further, by performing exposure and development processing, a cylindrical formation layer (lens marker) serving as a base of the microlens is produced at the microlens placement site.
In this way, by forming the formation layer, when the resin composition for forming a microlens is dropped in a subsequent process, the resin composition spreads spherically on the formation layer due to surface tension, and this resin composition Does not spread over a wider area than the formation layer. Therefore, variations in lens diameter and height are less likely to occur. In addition, as said lens marker, what was disclosed by Unexamined-Japanese-Patent No. 2002-331532 etc. is mentioned, for example. Further, an optical path for transmitting an optical signal may be formed only in a portion where the microlens of the solder resist layer is disposed.

Also in the IC chip mounting substrate 620 having such a configuration, electrical signals transmitted through external optical components (such as an optical fiber and an optical waveguide) are transmitted through the microlenses 646a to 646d and the optical path 642 for transmitting an optical signal. Is transmitted to the light receiving element 639 (light receiving unit 639a), converted into an electric signal by the light receiving element 639, and then sent to the IC chip 640 via the wire bonding 649, the conductor circuit 624, the via hole 627, etc. Will be processed.

Further, in the IC chip mounting substrate 620, since solder bumps 637 are formed on the solder resist layer 634 via a metal plating layer, electrical signal transmission between the IC chip 640 and the external substrate is performed by soldering. This can be done via the bump 637.

When the solder bumps are formed in this way, the IC chip mounting substrate can be connected to an external substrate such as a motherboard substrate via the solder bumps. In this case, the self-alignment of the solder By the action, the IC chip mounting substrate can be arranged at a predetermined position.

Further, as the shape of the optical path for optical signal transmission of the concave shape, both the part formed in the insulating layer of the optical path for optical signal transmission and the part that penetrates the solder resist layer of the optical path for optical signal transmission, for example, , A cylinder, a prism, an elliptic cylinder, a shape in which a plurality of cylinders are arranged in parallel and a part of side surfaces of adjacent cylinders are connected, a columnar body having a bottom surface surrounded by straight lines and arcs, and the like. Note that the portion formed in the insulating layer and the portion formed in the solder resist layer do not necessarily have the same shape.

Further, the cross-sectional area of the concave optical signal transmission optical path is preferably 100 mm ² or more. More desirably, it is 200 mm ² or more. With this size, an optical signal can be transmitted and received regardless of the size of the wavelength.

In the description of the IC chip mounting substrate of the third embodiment shown in FIG. 6, the IC chip mounting substrate on which the light receiving element is mounted as the optical element has been described. However, for the IC chip mounting of the above-described embodiment. In the substrate, a light emitting element may be mounted as an optical element instead of the light receiving element. In this case, the configuration of the IC chip mounting substrate is the same as the above except that the light receiving element is replaced with the light emitting element. Good. Further, both the light receiving element and the light emitting element may be mounted.

In the optical communication device according to the third aspect of the present invention, such an IC chip mounting substrate is mounted on a motherboard substrate.
The motherboard for mother board has a conductor circuit and an insulating layer laminated on at least one surface of the board, an optical waveguide, and an optical path for optical signal transmission.
An optical waveguide is formed on the mother board, and an optical signal can be transmitted through the optical waveguide.
Examples of the optical waveguide include an organic optical waveguide made of a polymer material or the like, an inorganic optical waveguide made of quartz glass, a compound semiconductor, or the like. Among these, an organic optical waveguide made of a polymer material or the like is desirable. This is because it has excellent adhesion to the insulating layer and is easy to process.
The polymer material is not particularly limited as long as it has little absorption in the communication wavelength band, and a thermosetting resin, a thermoplastic resin, a photosensitive resin, or a resin in which a part of the thermosetting resin is sensitized. And a resin composite of a thermosetting resin and a thermoplastic resin, a composite of a photosensitive resin and a thermoplastic resin, and the like.

Specifically, acrylic resin such as PMMA (polymethyl methacrylate), deuterated PMMA, deuterated fluorinated PMMA, polyimide resin such as fluorinated polyimide, epoxy resin, UV curable epoxy resin, polyolefin resin, deuterium Examples thereof include a silicone resin such as a fluorinated silicone resin, a siloxane resin, and a polymer produced from benzocyclobutene. In addition, when the optical waveguide is a multimode optical waveguide, the material is preferably acrylic resin, epoxy resin, or UV curable epoxy resin. When the optical waveguide is a single mode optical waveguide, The material is preferably a polyimide resin, a silicone resin, or a siloxane resin.

Further, the thickness of the core portion of the optical waveguide is desirably 1 to 100 μm, and the width is desirably 1 to 100 μm. If the width is less than 1 μm, the formation may not be easy. On the other hand, if the width exceeds 100 μm, it may hinder the degree of freedom in designing a conductor circuit or the like constituting the multilayer printed wiring board. .
Further, it is desirable that the ratio between the thickness and width of the core portion of the optical waveguide is close to 1: 1. This is because the planar shape of the light receiving part of the light receiving element or the light emitting part of the light emitting element is usually circular. In addition, the ratio of the thickness to the width is not particularly limited, and may be about 1: 2 to about 2: 1.

Furthermore, when the optical waveguide is a single-mode optical waveguide having a communication wavelength of 1.31 μm or 1.55 μm, the thickness and width of the core portion are more preferably 5 to 15 μm, and about 10 μm. It is particularly desirable. When the optical waveguide is a multimode optical waveguide with a communication wavelength of 0.85 μm, the thickness and width of the core portion are more preferably 20 to 80 μm, and particularly preferably about 50 μm. .

The optical waveguide may contain particles. This is because cracks are less likely to occur in the optical waveguide when the particles are blended. That is, when particles are not mixed in the optical waveguide, cracks may occur in the optical waveguide due to the difference in thermal expansion coefficient between the optical waveguide and other layers (substrate, insulating layer, etc.). However, if the difference in thermal expansion coefficient from the other layers is reduced by blending particles in the optical waveguide and adjusting the thermal expansion coefficient, cracks are less likely to occur in the optical waveguide.
In addition to the resin component, the optical waveguide may contain particles such as resin particles, inorganic particles, and metal particles. This is because the inclusion of these particles makes it possible to match the thermal expansion coefficient between the optical waveguide and the insulating layer, solder resist layer, or the like.

Examples of the resin particles include a thermosetting resin, a thermoplastic resin, a photosensitive resin, a resin in which a part of the thermosetting resin is sensitized, a resin composite of a thermosetting resin and a thermoplastic resin, and a photosensitive property. What consists of a composite_body | complex etc. of resin and a thermoplastic resin is mentioned.
Specifically, thermosetting resins such as epoxy resins, phenol resins, polyimide resins, bismaleimide resins, polyphenylene resins, polyolefin resins, fluororesins; thermosetting groups of these thermosetting resins (for example, epoxy in epoxy resins) Resin that has been reacted with methacrylic acid, acrylic acid or the like to give an acrylic group; phenoxy resin, polyether sulfone (PES), polysulfone (PSF), polyphenylene sulfone (PPS), polyphenylene sulfide (PPES), polyphenyl Examples thereof include thermoplastic resins such as ether (PPE) and polyetherimide (PI); photosensitive resins such as acrylic resins.
Moreover, what consists of the resin composite of the said thermosetting resin and the said thermoplastic resin, the resin to which the said acrylic group was provided, the said photosensitive resin, and the said thermoplastic resin can also be used.

Moreover, as the resin particles, resin particles made of rubber can be used.
Examples of the inorganic particles include aluminum compounds such as alumina and aluminum hydroxide, calcium compounds such as calcium carbonate and calcium hydroxide, potassium compounds such as potassium carbonate, magnesium compounds such as magnesia, dolomite and basic magnesium carbonate, silica And silicon compounds such as zeolite and titanium compounds such as titania. Further, silica and titania mixed at a certain ratio and melted and homogenized may be used.

Moreover, what consists of phosphorus or a phosphorus compound can also be used as said inorganic particle.
Examples of the metal particles include those made of gold, silver, copper, palladium, nickel, platinum, iron, zinc, lead, aluminum, magnesium, calcium and the like.
These resin particles, inorganic particles and metal particles may be used alone or in combination of two or more.
The particles are preferably inorganic particles, and particles made of silica, titania or alumina are desirable. Moreover, particles having a mixed composition formed by mixing and melting at least two of silica, titania and alumina are also desirable.
The shape of the particles such as the resin particles is not particularly limited, and examples thereof include a spherical shape, an elliptical spherical shape, a crushed shape, and a polyhedral shape.

The particle size of the particles is preferably shorter than the communication wavelength. This is because if the particle size is longer than the communication wavelength, transmission of the optical signal may be hindered.
More preferably, the particle size has a lower limit of 0.01 μm and an upper limit of 0.8 μm. When particles outside this range are included, the particle size distribution becomes too wide, and when mixed in the resin composition, the viscosity of the resin composition varies greatly, which is a reproduction of the case where a resin composition is prepared. This is because it may become difficult to prepare a resin composition having a predetermined viscosity.

More preferably, the particle size has a lower limit of 0.1 μm and an upper limit of 0.8 μm. Within this range, it is suitable to apply the resin composition using spin coating, roll coating, etc., and when preparing a resin composition in which particles are mixed, it becomes easy to adjust to a predetermined viscosity. .
It is particularly desirable that the lower limit of the particle size is 0.2 μm and the upper limit is 0.6 μm. This range is particularly suitable for application of the resin composition and formation of the core portion of the optical waveguide. Further, the variation of the formed optical waveguides, particularly the variation of the core portion is minimized, and the characteristics of the motherboard for the mother board are particularly excellent.
Moreover, as long as it is a particle | grain which has a particle size of this range, the particle | grains of 2 or more types of different particle sizes may be contained.
Moreover, as long as it is a particle | grain which has a particle size in the said range, you may contain the particle | grains of 2 or more types of different particle sizes.

The desirable lower limit of the compounding amount of the particles is 10% by weight, and the more desirable lower limit is 20% by weight. On the other hand, the desirable upper limit of the particles is 80% by weight, and the more desirable upper limit is 70% by weight. If the blending amount of the particles is less than 10% by weight, the effect of blending the particles may not be obtained. If the blending amount of the particles exceeds 80% by weight, the transmission of the optical signal may be hindered. It is.

Further, the shape of the optical waveguide is not particularly limited, but a sheet shape is preferable because it is easy to form.
When the optical waveguide is composed of a core part and a clad part, the particles may be blended in both the core part and the clad part, but the core part is blended with particles. It is desirable that the particles are blended only in the clad part covering the periphery of the core part. The reason is as follows.
That is, when the particles are mixed in the optical waveguide, an air layer may be generated at the interface between the particles and the resin component depending on the adhesion between the particles and the resin component of the optical waveguide. While the refractive direction of light changes depending on the air layer, the transmission loss of the optical waveguide may increase, whereas when the particles are blended only in the cladding part, by blending the particles as described above, This is because the problem that the transmission loss of the optical waveguide becomes large does not occur and cracks are hardly generated in the optical waveguide.

Further, it is desirable that an optical path conversion mirror is formed in the optical waveguide. This is because the optical path can be changed to a desired angle by forming the optical path conversion mirror.
The optical path conversion mirror can be formed by cutting one end of the optical waveguide, as will be described later. Further, instead of forming the optical path conversion mirror in the optical waveguide, a member having an optical path conversion unit may be disposed at the end of the end of the optical waveguide.

In the motherboard for the mother board, an optical signal transmission optical path is formed at least in the insulating layer and the solder resist layer, and a resin other than a part that penetrates the solder resist layer of the optical signal transmission optical path It is desirable that the composition is filled.
Here, examples of the resin composition to be filled include those similar to the resin composition to be filled in the optical path for optical signal transmission in the above-described IC chip mounting substrate of the present invention.

In the optical communication device, the diameter of the cross section of the optical signal transmission optical path passing through the optical solder resist layer is smaller than the diameter of the cross section of the portion formed in the insulating layer. Also good.
In addition, the specific size of the diameter of the cross section of the portion that penetrates the solder resist layer of the optical signal transmission optical path may be appropriately selected according to the design of the IC chip mounting substrate, but is usually about 50 to 490 μm. It is desirable that

Further, in the mother board, the end portion of the resin composition filled in a portion other than a portion penetrating the solder resist layer of the optical path for transmitting the optical signal of the resin composition, the optical signal transmitting A microlens may be disposed in a portion of the optical path that penetrates the solder resist layer. This is because the optical signal can be reliably transmitted by disposing the microlens.
In addition, as a material of the said microlens, characteristics, such as a transmittance | permeability, the thing similar to the microlens arrange | positioned on the board | substrate for IC chip mounting of this invention mentioned above is mentioned.
Moreover, in the said board | substrate for motherboards, the board | substrate for IC chip mounting of this invention is not specifically limited, Similarly, the area | region where the said micro lens is arrange | positioned may be surface-treated.

In the above motherboard substrate, when a solder resist layer is formed on the outermost layer, the lower limit of the thickness of the solder resist layer is preferably 10 μm, and more preferably 15 μm. On the other hand, the upper limit is desirably 40 μm, and more desirably 30 μm.

In the motherboard for motherboard, it is desirable that conductor circuits sandwiching the substrate are connected via through holes, and conductor circuits sandwiching the insulating layer are connected via via holes. This is because the high-density wiring of the IC chip mounting substrate can be realized and the size can be reduced.

In the optical communication device, an IC chip mounting substrate sealing layer is formed so as to be in contact with the outer periphery of the IC chip mounting substrate. As a material of the IC chip mounting substrate sealing layer, Examples of the optical element sealing layer according to the above-described IC chip mounting substrate of the first aspect of the invention include the same.
Therefore, the IC chip mounting substrate sealing layer is preferably made of resin. Of course, the IC chip mounting substrate sealing layer may be made of solder.

Further, as will be described later with reference to the drawings, in the optical communication device, it is desirable that a gap is formed in a portion of the optical signal transmission optical path that is in contact with the IC chip mounting substrate. The reason is that, in the IC chip mounting substrate according to the first aspect of the present invention, the optical signal transmission optical path is excellent in optical transmission property as well as the reason why it is desirable that a gap is formed in the portion in contact with the optical element of the optical signal transmission optical path. Because it becomes.

Hereinafter, embodiments of the optical communication device of the third aspect of the present invention will be described with reference to the drawings.
FIG. 7: is sectional drawing which shows typically an example of embodiment of the device for optical communication of 3rd this invention.
FIG. 7 shows an optical communication device 760 in which an IC chip mounting substrate 2720 on which a light receiving element 2739 is mounted and an IC chip mounting substrate 1720 on which a light emitting element 1738 is mounted are mounted on a motherboard 720. Has been. As the IC chip mounting substrates 1720 and 2720, the IC chip mounting substrate according to the first aspect of the present invention in which the IC chip is mounted is mounted.

The IC chip mounting substrate 1720 is formed by laminating a conductor circuit 1724 and an insulating layer 1722 on both surfaces of the substrate 1721. Between the conductor circuits sandwiching the substrate 1721 and between the conductor circuits sandwiching the insulating layer 1722, respectively. They are electrically connected by through holes (not shown) and via holes 1727. A solder resist layer 1734 is formed on the outermost layer.

In the IC chip mounting substrate 1720, an optical signal transmission optical path 1742 is provided so as to penetrate the substrate 1721, the insulating layer 1722, and the solder resist layer 1734.
In this optical signal transmission optical path 1742, a resin composition 1747 is filled in a portion penetrating the substrate 1721 and the insulating layer 1722. In addition, the microlenses 1749 and 1746 are respectively provided on the side of the resin composition 1747 on which the light emitting element 1738 is mounted and on the opposite end thereof, and the portions penetrating the solder resist layer of the optical path 1742 for optical signal transmission. Is arranged.

On one surface of the IC chip mounting substrate 1720, a light emitting element 1738 is surface-mounted via a solder connection portion 1744 so that the light emitting portion 1738 a faces the optical path 1742 for optical signal transmission. In the IC chip mounting substrate 1720, an optical element sealing layer 1748 is formed so as to be in contact with the outer periphery of the light emitting element 1738.
Although not shown, an IC chip is mounted on the surface of the IC chip mounting substrate 1720 on the same side as the side on which the light emitting element 1738 is mounted via a solder connection portion.

In addition, the IC chip mounting substrate 2720 is formed by laminating a conductor circuit 2724 and an insulating layer 2722 on both surfaces of the substrate 2721, and between the conductor circuits sandwiching the substrate 2721 and between the conductor circuits sandwiching the insulating layer 2722, Each is electrically connected through a through hole (not shown) and a via hole 2727. A solder resist layer 2734 is formed on the outermost layer.

In this IC chip mounting substrate 2720, an optical signal transmission optical path 2742 is provided so as to penetrate the substrate 2721, the insulating layer 2722, and the solder resist layer 2734. In this optical signal transmission optical path 2742, a resin composition 2747 is filled in a portion penetrating the substrate 2721 and the insulating layer 2722. In addition, each of the resin composition 2747 on the side where the light receiving element 2739 is mounted and the opposite end thereof, which passes through the solder resist layer 2734 of the optical signal transmission optical path 2742, includes a microlens 2749, 2746 is provided.

On one surface of the IC chip mounting substrate 2720, a light receiving element 2739 is surface-mounted via a solder connection portion 2744 so that the light receiving portion 2739a faces the optical path 2742 for optical signal transmission. In the IC chip mounting substrate 2720, an optical element sealing layer is formed so as to be in contact with the outer periphery of the light receiving element 2739.
Although not shown, an IC chip is mounted on the surface of the IC chip mounting substrate 2720 on the same side as the side on which the light receiving element 2739 is mounted via a solder connection portion.

In addition, the motherboard 720 includes a conductor circuit 724 and an insulating layer 722 formed on both surfaces of the substrate 721, and between the conductor circuits sandwiching the substrate 721 and between the conductor circuits sandwiching the insulating layer 722, respectively. They are electrically connected by a through hole 729 and a via hole (not shown). A solder resist layer 734 is formed as the outermost layer.
In this mother board 720, an optical signal transmission optical path 742 is provided so as to penetrate the board 721, the insulating layer 722, and the solder resist layer 734.

In this optical signal transmission optical path 742, the diameter of the cross section of the portion that penetrates the solder resist layer 734 is smaller than the diameter of the cross section of the portion that penetrates the substrate 721 and the insulating layer 722. In the mother board 720 constituting the optical communication device of the third aspect of the present invention, the diameter of the cross section of the portion that penetrates the solder resist layer 734 is not necessarily the diameter of the cross section of the portion that penetrates the substrate 721 and the insulating layer 722. It does not have to be smaller.

An optical waveguide 750 composed of a core 751 and a clad 752 is formed on the outermost insulating layer 722 opposite to the side on which the IC chip mounting substrates 1720 and 2720 of the motherboard 720 are mounted.
In addition, an optical path conversion mirror is formed at each end portion of the optical waveguide 750 so that an optical signal can be transmitted between the optical waveguide 750 and the optical path 742 for transmitting an optical signal. .

Here, as will be described later, the optical waveguide 750 is once laminated with a resin composition on the entire surface or a part of the outermost insulating layer, and then a predetermined portion is cut with a diamond saw or the like having a V-shaped 90 ° tip. It is formed by processing. In addition, in the motherboard 720, a portion where both ends thereof are optically connected to the optical signal transmission optical path 742 actually functions as an optical waveguide.

In addition, microlenses 746a and 746b are disposed on the side opposite to the side where the optical waveguide 750 is formed in the optical path 742 for transmitting an optical signal and through the solder resist layer. Here, each of the micro lenses 746a and 746b is disposed at a position corresponding to each end portion of the core 751 in which an optical path conversion mirror is formed at the end portion.

In the optical communication device 760, IC chip mounting substrates 1720 and 2720 are mounted on the surface of the motherboard substrate 720 opposite to the side on which the optical waveguide 750 is formed via solder connection portions 1743 and 2743. Yes.
Here, each of the IC chip mounting substrates 1720 and 2720 is mounted at a predetermined position by a self-alignment action.

Further, IC chip mounting substrate sealing layers 748a and 748b are formed on the solder resist layer 734 on one surface so as to be in contact with the outer circumferences of the IC chip mounting substrates 1720 and 2720, respectively. A gap is formed immediately below the optical path for optical signal transmission formed in each of the mounting substrate sealing layers 748a and 748b. Therefore, the IC chip mounting substrate sealing layers 748a and 748b are not formed on the portions of the optical signal transmission optical path that are in contact with the IC chip mounting substrates 1720 and 2720.
By forming such IC chip mounting substrate sealing layers 748a and 748b, optical signal transmission optical paths formed on the IC chip mounting substrates 1720 and 2720 and optical signal transmission formed on the motherboard substrate. Dust and foreign matter do not enter the optical path 742 for use, and transmission of optical signals is not hindered by the dust and foreign matter.
Further, the optical signal can be efficiently collected by the microlens.

In the optical communication device 760 having such a configuration, an electrical signal from an IC chip (not shown) mounted on the IC chip mounting substrate 1720 is converted into an optical signal by the light emitting element 1738, and the light emitting element 1738 ( The optical signal emitted from the light emitting unit 1738a) includes a microlens 1749, an optical signal transmission optical path 1742, a microlens 1746, a microlens 746a, an optical signal transmission optical path 742, an optical waveguide 750, an optical signal transmission optical path 742, and a microlens. 746b, microlens 746, optical signal transmission optical path 2742, and microlens 2749, the light is transmitted to light receiving element 2739 (light receiving unit 2739a) and further converted into an electric signal by light receiving element 2739, and then IC chip mounting substrate 2720. Is transmitted to the IC chip (not shown) mounted on the It is the thing.
In such an optical communication device, dust and foreign matter do not enter the optical signal transmission optical path, so that an optical signal can be transmitted reliably.

Further, the embodiment of the optical communication device of the present invention is not limited to the embodiment shown in FIG. 7, and may be an embodiment shown in FIG. 8, for example.
FIG. 8 is a cross-sectional view schematically showing another example of the embodiment of the optical communication device of the present invention. FIG. 8 shows an optical communication device 860 in which an IC chip mounting substrate 1820 on which a light emitting element 1838 is mounted and an IC chip mounting substrate 2820 on which a light receiving element 2839 is mounted are mounted on a motherboard 820. Has been. As the IC chip mounting substrates 1820 and 2820, the IC chip mounting substrate of the third embodiment is mounted.

The optical communication device 860 is different from the optical communication device 760 shown in FIG. 7 in the structure of the IC chip mounting substrates 1820 and 2820, but the structure of the motherboard 820 is the same as that of the motherboard 720. Are identical.
Therefore, here, an embodiment of the optical communication device 860 will be described focusing on the structure of the IC chip mounting substrates 1820 and 2820.

The IC chip mounting substrate 1820 is formed by laminating a conductor circuit 1824 and an insulating layer 1822 on both surfaces of the substrate 1821. Between the conductor circuits sandwiching the substrate 1821 and between the conductor circuits sandwiching the insulating layer 1822, respectively. The through hole 1829 and the via hole 1827 are electrically connected. A solder resist layer 1834 is formed on the outermost layer.

The IC chip mounting substrate 1820 is provided with an optical path for optical signal transmission 1842 having a concave shape.
In this optical signal transmission optical path 1842, a light emitting element 1838 and an IC chip (not shown) are mounted by wire bonding 1849, and a portion formed on the insulating layer 1822 of the optical signal transmission optical path 1842 Is filled with a resin composition 1847.
In addition, a microlens 1846 is formed at a part of the end portion of the resin composition 1847 opposite to the side where the light emitting element 1838 is mounted and through the solder resist layer 1834 of the optical path for optical signal transmission 1842. It is arranged.

In addition, the IC chip mounting substrate 2820 is formed by laminating a conductor circuit 2824 and an insulating layer 2822 on both surfaces of the substrate 2821. Between the conductor circuits sandwiching the substrate 2821 and between the conductor circuits sandwiching the insulating layer 2822, Each is electrically connected by a through hole 2829 and a via hole 2827. A solder resist layer 2834 is formed as the outermost layer.

This IC chip mounting substrate 2820 is provided with an optical path 2842 for concave optical signal transmission.
In this optical signal transmission optical path 2842, a light receiving element 2839 and an IC chip (not shown) are mounted by wire bonding 2849, and a portion formed in the insulating layer 2822 of the optical signal transmission optical path 2842 Is filled with a resin composition 2847.
Further, a microlens 2846 is provided at a part of the end of the resin composition 2847 opposite to the side on which the light receiving element 2839 is mounted and through the solder resist layer 2834 of the optical signal transmission optical path 2842. It is arranged.

Further, as described above, the mother board 820 has the same configuration as the mother board shown in FIG.
In the optical communication device 860, IC chip mounting substrates 1820 and 2820 are mounted via solder connection portions 1843 and 2843 on the surface of the motherboard substrate 820 opposite to the side on which the optical waveguide 850 is formed. Yes.
Here, each of the IC chip mounting substrates 1820 and 2820 is mounted at a predetermined position by a self-alignment action.

Further, IC chip mounting substrate sealing layers 848a and 848b are formed on the solder resist layer 834 on one surface of the motherboard substrate 820 so as to be in contact with the outer circumferences of the IC chip mounting substrates 1820 and 2820, respectively. A gap is formed immediately below the optical signal transmission optical path formed in each of the IC chip mounting substrate sealing layers 848a and 848b. Therefore, the IC chip mounting substrate sealing layers 848a and 848b are not formed on the portions of the optical signal transmission optical path that are in contact with the IC chip mounting substrates 1820 and 2820.
By forming such IC chip mounting substrate sealing layers 848a and 848b, optical signal transmission optical paths formed on the IC chip mounting substrates 1820 and 2820, and optical signal transmission formed on the motherboard substrate. There is no entry of dust or foreign matter into the optical path for use, and transmission of optical signals is not hindered by the dust or foreign matter.
Further, the optical signal can be efficiently collected by the microlens.

In the optical communication device 860 having such a configuration, an electrical signal from an IC chip (not shown) mounted on the IC chip mounting substrate 1820 is converted into an optical signal by the light emitting element 1838, and the light emitting element 1838 ( The optical signal emitted from the light emitting unit 1838a) is an optical signal transmission optical path 1842, a micro lens 1846, a micro lens 846a, an optical signal transmission optical path 842, an optical waveguide 850, an optical signal transmission optical path 842, a micro lens 846b, and a micro lens. The IC chip mounted on the IC chip mounting board 2820 after being transmitted to the light receiving element 2839 (light receiving unit 2839a) through the optical path 2846 and the optical signal transmitting optical path 2842 and further converted into an electric signal by the light receiving element 2839. (Not shown) and processed.
In such an optical communication device, dust and foreign matter do not enter the optical signal transmission optical path, so that an optical signal can be transmitted reliably.

Further, in the optical communication device shown in FIGS. 7 and 8, one channel optical element (light emitting element, light receiving element) is mounted on the IC chip mounting substrate. An optical signal transmission optical path for transmitting an optical signal is formed on each of the IC chip mounting substrate and the motherboard substrate.
However, the embodiment of the optical communication device of the present invention is not limited to the embodiment as shown in FIGS. 7 and 8, and the first or second IC chip of the present invention is mounted on the above-mentioned mother board. Any configuration may be used as long as the mounting substrate or the IC chip mounting substrate of the third embodiment is mounted.

Therefore, a multi-channel optical element may be mounted on the IC chip mounting substrate, and an optical signal of the multi-channel optical element is transmitted to each of the IC chip mounting substrate and the motherboard substrate. Accordingly, an optical signal transmission optical path having a collective through-hole structure, an optical signal transmission optical path having an individual through-hole structure, or the like may be formed.
When a plurality of IC chip mounting substrates are mounted on the motherboard, the IC chip mounting substrate on which the optical signal transmission optical path having a collective through-hole structure is formed and the optical signal transmission optical path having a concave shape are formed. An IC chip mounting substrate having a different optical signal transmission optical path structure, such as an IC chip mounting substrate, may be mounted on one motherboard substrate.

Furthermore, in the optical communication device of the embodiment as shown in FIG. 7, when the microlens is arranged, it is desirable to arrange the microlens at all six positions shown in the embodiment of FIG. This is because the reliability of the transmission capability of the optical signal from the light emitting element to the light receiving element is excellent. In addition, the same thing became clear also in the optical communication device of the embodiment shown in FIG.
Further, a microlens may be disposed on the optical element mounted on the IC chip mounting substrate.
It is also desirable that microlenses are disposed at least at locations (four locations) where the IC chip mounting substrate and the motherboard substrate face each other.

In the optical communication device of the third aspect of the present invention, a dam may be formed between the IC chip mounting substrate and the solder resist layer of the motherboard substrate.
This is because by forming the dam, the IC chip mounting substrate sealing layer can be formed at a desired position on the solder resist layer of the motherboard substrate.
In particular, when the IC chip mounting substrate sealing layer is formed by potting, the IC chip mounting substrate between the optical signal transmission optical path of the IC chip mounting substrate and the optical signal transmission optical path of the motherboard substrate. Since the inflow of the sealing layer can be prevented, it is suitable that a dam is formed.

Further, in the optical communication device of the third aspect of the present invention, in the embodiment shown in FIG. 7, the IC chip mounting in which the optical element sealing layer is not formed in the portion in contact with the optical element of the optical signal transmission optical path An IC chip mounting substrate sealing layer is formed on a portion of the optical signal transmission optical path formed on the motherboard substrate in contact with the IC chip mounting substrate. Of course, the embodiment of the device for optical communication according to the third aspect of the present invention is not limited to such a form.

Specifically, there are four possible combinations of embodiments that the third embodiment of the optical communication device of the present invention can take, including the embodiment shown in FIG.
That is, (1) an IC chip mounting substrate on which an optical element sealing layer is not formed is mounted on a mother board substrate at a portion in contact with an optical element of an optical path for optical signal transmission, and further formed on a motherboard substrate. The form in which the IC chip mounting substrate sealing layer is not formed on the portion of the optical path for optical signal transmission that is in contact with the IC chip mounting substrate (the form of FIG. 7),
(2) An IC chip mounting board in which an optical element sealing layer is formed on a portion of the optical signal transmission optical path in contact with the optical element is mounted on the mother board, and further formed on the motherboard board. A form in which the IC chip mounting substrate sealing layer is not formed on the portion of the optical path for optical signal transmission that contacts the IC chip mounting substrate,
(3) An IC chip mounting substrate on which an optical element sealing layer is not formed is mounted on the mother board substrate at a portion in contact with the optical element on the optical signal transmission optical path, and further formed on the motherboard substrate. A mode in which an IC chip mounting substrate sealing layer is formed on a portion of the optical path for optical signal transmission that is in contact with the IC chip mounting substrate;
(4) An IC chip mounting substrate in which an optical element sealing layer is formed in a portion in contact with the optical element in the optical path for transmitting an optical signal is mounted on the mother board, and further, the light formed on the motherboard substrate. There are four types, in which an IC chip mounting substrate sealing layer is formed on the portion of the optical path for signal transmission that contacts the IC chip mounting substrate.

All of these embodiments achieve the object of the third aspect of the present invention described above, that is, preventing dust and foreign matter from entering the optical path for optical signal transmission and ensuring excellent optical signal transmission capability. Among these, the form (2) is particularly desirable. The reason is as follows.

When comparing the distance between the optical element and the IC chip mounting substrate and the distance between the IC chip mounting substrate and the motherboard substrate, the former is usually as narrow as 50 μm or less (about 100 μm at most). On the other hand, the latter has a certain distance of about 300 μm (approximately 100 to 800 μm).
Here, in consideration of forming each of the optical element sealing layer and the IC chip mounting substrate sealing layer, when forming the optical element sealing layer, the optical element and the IC chip mounting substrate are formed. The resin composition for forming the optical element sealing layer when the optical element sealing layer is not formed in the portion in contact with the optical element in the optical path for optical signal transmission because the gap distance between the optical element and the optical path is narrow As a result, the degree of freedom of selection becomes smaller, and the control of the formation process is required to have extremely high accuracy. On the other hand, when the IC chip mounting substrate sealing layer is formed, the gap between the IC chip mounting substrate and the motherboard substrate has a certain distance, so it is relatively easily formed on the motherboard substrate. The IC chip mounting substrate sealing layer is not formed on the portion of the optical path for optical signal transmission that is in contact with the IC chip mounting substrate, so that only the vicinity of the outer periphery can be sealed. The resin composition for forming the substrate sealing layer for mounting an IC chip for forming can also be freely selected to some extent.
From such a point, the embodiment (2) is particularly desirable as an embodiment of the optical communication device of the third aspect of the present invention.

The optical communication device according to the third aspect of the present invention described so far has a substrate and an insulating layer made of a resin material.
However, even when the substrate, the insulating layer, and the like are made of a material other than resin, such as glass or ceramic, the same effect as the third aspect of the present invention can be obtained.
That is, an IC chip mounting substrate on which an optical element is mounted on a wiring board made of glass or ceramic is mounted on a motherboard substrate on which an optical waveguide is formed on a wiring board made of glass or ceramic. Even in the optical communication device in which the IC chip mounting substrate sealing layer is formed so as to be in contact with the outer periphery of the optical substrate, the same effect as the above-described optical communication device of the third aspect of the present invention can be obtained. . The same applies to the case where only one of the IC chip mounting substrate and the motherboard substrate is made of glass, ceramic, or the like.
When such a wiring board made of glass or ceramic is used, the IC chip mounting substrate sealing layer is preferably made of solder.

Next, the manufacturing method of the device for optical communication of 3rd this invention is demonstrated. The optical communication device of the present invention can be manufactured by separately manufacturing an IC chip mounting substrate and a motherboard substrate, and then connecting them via solder or the like.

The method for manufacturing the IC chip mounting substrate is as described above for the IC chip mounting substrates of the first and second aspects of the present invention.
A method for manufacturing the IC chip mounting substrate of the third embodiment will be briefly described below.

(1) When manufacturing the IC chip mounting substrate of the third embodiment, first, the same method as the steps (1) to (9) of the method of manufacturing the IC chip mounting substrate of the first aspect of the present invention. Is used to manufacture a multilayer wiring board in which a conductor circuit and an insulating layer are laminated on both sides of a substrate.

(2) Next, an optical path recess is formed on the multilayer wiring board.
The recess for the optical path can be formed by, for example, a method similar to the method for forming the through hole for the optical path, that is, drilling or laser processing.
Further, when forming the recess for the optical path, it is desirable to form an IC chip together with an optical element such as a light receiving element or a light emitting element.
In addition, when forming the concave portion for the optical path, when forming the insulating layer in the step of manufacturing the multilayer wiring board described above, an opening penetrating each insulating layer is formed, and the insulating layer is laminated. When completed, an optical path recess may be formed.

Moreover, after forming the said optical path recessed part, you may perform the roughening surface formation process which uses a desmear process and the wall surface as a roughening surface to the wall surface similarly to the case where the said optical path through-hole etc. are formed.
After forming the recess for the optical path, a conductor layer forming step for forming a conductor layer on the wall surface of the recess for the optical path may be performed as necessary, as in the case of forming the through hole for the optical path, etc. Further, when such a conductor layer forming step is performed, it is desirable to form the outermost conductor circuit on the outermost insulating layer.
In addition, after forming the conductor layer, a roughened surface may be formed on the wall surface of the conductor layer in the same manner as when the conductor layer is formed on the wall surface of the through hole for an optical path.

(3) Next, a resin composition filling step of filling the resin composition into the optical path for optical signal transmission having a concave shape formed in the multilayer wiring board (recess for optical path) is performed.
In the optical path for optical signal transmission, which is completed through a subsequent process by filling the uncured resin composition in the recess for the optical path and then performing a curing process, the portion formed on the substrate or the insulating layer is the resin composition. Things will be filled.
A specific method for filling the uncured resin composition is not particularly limited, and a method similar to the method for filling the resin composition in the through hole for an optical path such as printing or potting can be used.
Furthermore, when the resin composition is filled, it is desirable to polish the exposed surface of the resin composition and make the exposed surface flat. This is because by flattening the exposed surface, there is less possibility that transmission of an optical signal will be hindered. The polishing treatment can be performed by a method similar to the method performed after the resin composition is filled in the optical path through hole.

Before performing the resin composition filling step, it is necessary to mount an optical element before that, and when mounting an IC chip in the recess for the optical path, Must be implemented. It should be noted that the IC chip may be mounted according to the design, and not necessarily mounted in the optical path recess.
Therefore, a method for mounting the optical element and the IC chip in the optical path recess will be described below.

First, a part of the conductor circuit is exposed on the bottom surface of the recess for the optical path so as to be a connection terminal for an optical element or the like. Thereafter, if necessary, a plating layer may be formed on the exposed portion of the conductor circuit.
Next, after the optical element and the IC chip are attached to the bottom surface of the recess for the optical path, the optical element and the IC chip are electrically connected to the conductor circuit of the multilayer wiring board.

The optical element and the IC chip can be attached by, for example, a eutectic bonding method, a solder bonding method, a resin bonding method, or the like. Further, an optical element or the like may be attached using a silver paste or a gold paste.
In the resin bonding method, a thermosetting resin such as an epoxy resin or a polyimide resin is used as a main agent, and a paste containing a curing agent, a filler, a solvent, etc. in addition to these resin components is applied on a multilayer wiring board, After placing the optical element or the like on the paste, the optical element or the like is attached by heating and curing the paste.
The paste can be applied by, for example, a dispensing method, a stamping method, a screen printing method, or the like.
When using a silver paste, the silver paste is applied on the multilayer wiring board, and then the optical element is mounted on the paste, and then the silver paste is baked to attach the optical element.

As a method for electrically connecting the optical element and the IC chip to the conductor circuit of the multilayer wiring board, it is desirable to use wire bonding. This is because the degree of freedom of design when attaching an optical element or the like is large and it is economically advantageous.
As the wire bonding, a conventionally known method, that is, a nail head bonding method or a wedge bonding method can be used.
The mounting of the optical element or the like may be performed by tape bonding, flip chip bonding, or the like.

(4) Next, a solder resist layer forming step of forming a solder resist layer having an opening (optical path opening) communicating with the optical signal transmission optical path (optical path recess) formed in the step (3) is performed. .
Specifically, for example, it can be performed by a method similar to the method used in the step (12) of the manufacturing method of the IC chip mounting substrate of the first present invention.
In this case as well, the shape of the optical path opening is not particularly limited, and the size of the opening in plan view may be larger than the concave part for the optical path, or may be the same or smaller. Also good.
An optical path opening may be formed for each optical signal.

Further, the optical path opening formed in the solder resist layer may be filled with an uncured resin composition in the same manner as the optical path recess. In some cases, a conductor layer may also be formed on the wall surface of the optical path opening formed in the solder resist layer.

Further, in this step, after forming the solder resist layer, the microlens is disposed in the end of the resin composition filled in the through hole for the optical path, and in the opening for the optical path formed in the solder resist layer. Also good. The arrangement of the microlenses can be performed by a method similar to the method used in the manufacturing method of the IC chip mounting substrate of the first aspect of the present invention.

(5) After that, the IC chip mounting substrate of the third embodiment is manufactured by forming solder pads and solder bumps in the same manner as the manufacturing method of the IC chip mounting substrate of the first aspect of the present invention. Can do.

Next, a method for manufacturing the mother board will be described in the order of steps.
(1) First, in the same manner as in steps (1) and (2) of the method for manufacturing an IC chip mounting substrate of the present invention, conductor circuits are formed on both surfaces of the substrate, and between the conductor circuits sandwiching the substrate. A through hole to be connected is formed. Also in this step, a roughened surface is formed on the surface of the conductor circuit and the wall surface of the through hole as necessary.

(2) Next, if necessary, an insulating layer and a conductor circuit are laminated on the substrate on which the conductor circuit is formed.
Specifically, the insulating layer and the conductor circuit may be laminated and formed using the same method as the steps (3) to (8) of the method for manufacturing an IC chip mounting substrate of the present invention.
Also in this step, as in the case of manufacturing an IC chip mounting substrate, a through hole penetrating the substrate and the insulating layer may be formed, or a lid plating layer may be formed.
Note that the step of laminating the insulating layer and the conductor circuit may be performed only once or a plurality of times.
Further, as a method of forming a conductor circuit on the insulating layer in this step, a subtractive method or the like may be used as in the case of manufacturing the IC chip mounting substrate.

Further, when forming an optical waveguide as will be described later, in the case where the optical waveguide is formed on the side facing the IC chip mounting substrate and the insulating layer on the opposite side across the substrate, in this step If necessary, a resin composition is filled therein, or a through hole for an optical path in which a conductor layer is formed on the wall surface is formed. This through hole for an optical path functions as an optical path for transmitting an optical signal.
The optical path through hole (optical signal transmission optical path) penetrating the substrate or the like may be formed after the optical waveguide is formed in the following step (3).

Moreover, the through hole for an optical path can be formed by, for example, drilling or laser processing.
Moreover, as a laser used by the said laser processing, the thing similar to the laser used when forming the opening for via holes is mentioned, for example.
The through hole for an optical path may be a collective through hole or an individual through hole.

(3) Next, an optical waveguide is formed at a predetermined position according to the design on the substrate and / or the insulating layer.
When the optical waveguide is formed using an inorganic material such as quartz glass as the material, the optical waveguide can be formed by attaching an optical waveguide that has been previously formed into a predetermined shape via an adhesive.
The optical waveguide made of the inorganic material can be formed by depositing an inorganic material such as LiNbO ₃ or LiTaO ₃ by a liquid phase epitaxy method, a chemical deposition method (CVD), a molecular beam epitaxy method, or the like. it can.

Further, as a method of forming an optical waveguide made of a polymer material, (1) a method of pasting an optical waveguide forming film previously formed into a film shape on a release film or the like on an insulating layer, or (2 ) A method of forming an optical waveguide directly on the insulating layer or the like by sequentially laminating and forming a lower clad, a core, and an upper clad on the insulating layer.
In addition, as a method for forming the optical waveguide, the same method can be used when the optical waveguide is formed on the release film or when the optical waveguide is formed on the insulating layer or the like.

Specifically, a method using reactive ion etching, an exposure development method, a mold forming method, a resist forming method, a method combining these, and the like can be used.
In the method using reactive ion etching, (i) first, a lower clad is formed on a release film, an insulating layer or the like (hereinafter simply referred to as a release film), and (ii) A core resin composition is applied onto the clad, and further subjected to a curing treatment as necessary to obtain a core-forming resin layer. (Iii) Next, a mask-forming resin layer is formed on the core-forming resin layer, and then the mask-forming resin layer is subjected to exposure and development treatment, whereby the core-forming resin layer is formed. A mask (etching resist) is formed.
(Iv) Next, reactive ion etching is performed on the core-forming resin layer to remove the core-forming resin layer in the portion where the mask is not formed, and a core is formed on the lower cladding. (V) Finally, an upper clad is formed on the lower clad so as to cover the core, thereby obtaining an optical waveguide.
This method using reactive ion etching can form an optical waveguide having excellent dimensional reliability. This method is also excellent in reproducibility.

In the exposure development method, (i) first, a lower clad is formed on a release film or the like, and (ii) next, a core resin composition is applied on the lower clad, and further if necessary. Then, a layer of the core-forming resin composition is formed by performing a semi-curing treatment.
(Iii) Next, a mask on which a pattern corresponding to the core-forming portion is drawn is placed on the core-forming resin composition layer, and then subjected to exposure and development, whereby the core is formed on the lower clad. Form. (Iv) Finally, an upper clad is formed on the lower clad so as to cover the core, thereby obtaining an optical waveguide.
Since this exposure and development method has a small number of steps, it can be suitably used for mass production of optical waveguides, and since there are few heating steps, stress is hardly generated in the optical waveguides.

In the mold forming method, (i) first, a lower clad is formed on a release film or the like, and (ii) next, a core forming groove is formed in the lower clad by mold formation. (Iii) Furthermore, the core resin composition is filled in the groove by printing, and then a curing process is performed to form the core. (Iv) Finally, an upper clad is formed on the lower clad so as to cover the core, thereby obtaining an optical waveguide.
This mold forming method can be suitably used for mass production of optical waveguides, and can form optical waveguides with excellent dimensional reliability. This method is also excellent in reproducibility.

In the resist forming method, (i) a lower clad is first formed on a release film or the like, and (ii) a resist resin composition is further applied on the lower clad, and then an exposure development process is performed. By applying, a core forming resist is formed on the core non-forming portion on the lower clad.
(Iii) Next, the resin composition for the core is applied to the non-resist forming portion on the lower clad, and (iv
Further, after the core resin composition is cured, the core forming resist is peeled off to form the core on the lower clad. (V) Finally, an upper clad is formed on the lower clad so as to cover the core, thereby obtaining an optical waveguide.
This resist forming method can be suitably used for mass production of optical waveguides, and can form optical waveguides with excellent dimensional reliability. This method is also excellent in reproducibility.

In the case of forming an optical waveguide made of a polymer material using these methods, when forming an optical waveguide in which particles are blended in the core, the mold forming method is preferable to the exposure development method. The reason is as follows.
That is, when a core forming groove is formed by forming a mold in the lower clad and then the core is formed by a mold forming method in which the core is formed in the groove, all the particles blended in the core are The core surface is flat and excellent in optical signal transmission because it enters into the core. On the other hand, when the core is formed by the exposure and development method, the particles from the core surface are developed in the core after development. May protrude from the surface of the core or may be formed with depressions on the surface of the core, and irregularities may be formed on the surface of the core. As a result, the transmission performance of the optical signal may deteriorate.

In addition, when forming an optical waveguide on an insulating layer or the like, the optical waveguide is formed by sequentially laminating a lower clad, a core, and an upper clad on the entire surface or a part of the insulating layer or the like. It is also possible to form an optical path conversion mirror at this location so that only a part of the laminated optical waveguide actually functions as the optical waveguide.

An optical path conversion mirror is formed in the optical waveguide.
The optical path conversion mirror may be formed before the optical waveguide is mounted on the insulating layer, or may be formed after the optical waveguide is mounted on the insulating layer, but the optical waveguide is formed directly on the insulating layer. Except in some cases, it is desirable to form an optical path conversion mirror in advance. This is because the work can be easily performed, and there is no risk of scratching or damaging other members constituting the multilayer printed wiring board, the board, the conductor circuit, the insulating layer, etc. during the work. .
The method for forming the optical path conversion mirror is not particularly limited, and a conventionally known formation method can be used. Specifically, machining using a diamond saw or blade with a V-shaped 90 ° tip, machining by reactive ion etching, laser ablation, or the like can be used. Further, instead of forming the optical path conversion mirror, an optical path conversion member may be embedded.
When a 90-degree optical path conversion mirror is formed in the optical waveguide, the angle formed by the surface contacting the substrate or insulating layer of the lower clad and the optical path conversion surface may be 45 degrees or 135 degrees. There may be.

Here, the method for forming the optical waveguide on the substrate or the outermost insulating layer has been described. However, when the multilayer printed wiring board is manufactured, the optical waveguide is disposed between the substrate and the insulating layer. Or, it may be formed between insulating layers.
In the case of forming an optical waveguide between the substrate and the insulating layer, in the step (1), after producing a substrate having a conductor circuit formed on both surfaces thereof, the same method as in the step (3) Thus, an optical waveguide can be formed at the above-mentioned position by forming an optical waveguide in a portion where a conductor circuit is not formed on the substrate and then forming an insulating layer by the same method as in the step (2).
When an optical waveguide is formed between insulating layers, at least one insulating layer is laminated on a substrate on which a conductor circuit is formed in the same manner as in the steps (1) and (2). Thereafter, an optical waveguide is formed on the insulating layer in the same manner as in the above step (3), and then, the optical waveguide is formed between the insulating layers by repeating the same step as in the above step (2). Can be formed.

(4) Next, if necessary, a solder resist layer is formed. The solder resist layer can be formed, for example, by the following steps (a) and (b).

(A) First, a layer of a solder resist composition is formed on the outermost layer of a multilayer wiring board in which a through hole for an optical path filled with a resin composition is formed.
Formation of the layer of the solder resist composition can be performed using the same method as that used in the method of manufacturing the IC chip mounting substrate.

(B) Next, an opening (hereinafter also referred to as an optical path opening) communicating with the through hole for an optical path formed in the step (2) is formed in the layer of the solder resist composition.
The optical path opening can be formed using a method similar to that used in the method of manufacturing the IC chip mounting substrate.

Further, when forming the optical path opening, it is desirable to simultaneously form a solder bump forming opening (an opening for mounting an IC chip or an optical element). The formation of the optical path opening and the formation of the solder bump forming opening may be performed separately.
In addition, when forming the solder resist layer, a resin film having an opening at a desired position is prepared in advance, and the resin film is attached to the solder resist having an optical path opening and a solder bump forming opening. A layer may be formed.

Through the steps (a) and (b), an optical path opening communicating with the optical path for transmitting optical signals is formed on the multilayer wiring board on which the optical path for transmitting optical signals (through hole for optical paths) is formed. Can be formed.

Further, the optical path opening formed in the solder resist layer may be filled with an uncured resin composition in the same manner as the optical path through hole.
In some cases, a conductor layer may also be formed on the wall surface of the optical path opening formed in the solder resist layer.

Further, in this step, after forming the solder resist layer, the microlens is disposed in the end portion of the resin composition filled in the through hole for the optical path and in the opening for the optical path formed in the solder resist layer. You may perform a lens arrangement | positioning process.
Moreover, when performing a micro lens arrangement | positioning process, you may give surface treatments, such as a water repellent process (a process by a water repellent coating agent) and a hydrophilic process previously. This is because microlenses having a desired shape can be disposed by performing the surface treatment.
The surface treatment and the microlens placement step can be performed using the same method as that used in the method for manufacturing an IC chip mounting substrate of the present invention.

(5) Thereafter, a mother board can be manufactured by forming solder pads and solder bumps.
The solder pads and solder bumps can be formed by a method similar to the method used in the method for manufacturing an IC chip mounting substrate of the present invention.
In some cases, an optical waveguide may be formed on the entire outermost layer of the substrate in the step (3), and the optical waveguide may serve as a solder resist layer.

The solder bumps may be formed as necessary. Even when the solder bumps are not formed, they are mounted via the IC chip mounting substrate to be mounted and the bumps of various surface mount electronic components. be able to.
In addition, the solder resist layer on the opposite side of the surface facing the IC chip mounting substrate does not need to form an external connection terminal, and if necessary, a pin is provided or a solder ball is formed. It is good also as PGA or BGA by doing.

The optical communication device of the present invention is manufactured by manufacturing an IC chip mounting substrate and a motherboard substrate using the method as described above, and then connecting the two via solder or the like. It can be manufactured by forming a substrate sealing layer for mounting an IC chip so as to be in contact with the outer periphery of the substrate.
Specifically, first, the IC chip mounting substrate on which the solder bumps are formed and the motherboard substrate on which the solder bumps are formed are arranged opposite to each other at predetermined positions in a predetermined direction, and then reflowed. Connect both. Note that solder bumps may be formed only on one of the opposing surfaces of the IC chip mounting substrate and the motherboard substrate. This is because the two can be electrically connected also in this case.

Next, an IC chip mounting substrate sealing layer is formed around the IC chip mounting substrate.
The IC chip mounting substrate sealing layer can be formed, for example, by potting an ineffective resin composition and then performing a curing process.
When the IC chip mounting substrate sealing layer is formed by potting, if the IC chip mounting substrate is formed so as to be in contact with the outer periphery of the IC chip mounting substrate, the IC chip mounting substrate is covered. You may form.

Also, when forming a dam on the solder resist layer of the motherboard substrate, the dam can be formed, for example, by printing an epoxy resin or a silicone resin, punched into a frame shape by a punching press, or framed by a router process. The glass-epoxy substrate or the like that has been cut out can be bonded by an adhesive or the like. In consideration of the gap between the IC chip mounting substrate and the solder resist layer of the motherboard substrate being usually about 300 μm (approximately 100 to 800 μm), printing an epoxy resin or a silicone resin, Alternatively, it is desirable to form the dam by bonding the dam base material with an adhesive made of an epoxy resin or the like.
Through such steps, the device for optical communication of the present invention can be manufactured.

Next, an optical communication device according to a fourth aspect of the present invention will be described.
According to a fourth aspect of the present invention, there is provided an optical communication device comprising: a motherboard substrate having a conductor circuit and an insulating layer laminated on at least one surface of the substrate; an optical waveguide; and an optical signal transmission optical path. And an optical communication device on which an IC chip mounting substrate on which an optical element is mounted is mounted,
A cap member is attached so as to cover at least the IC chip mounting substrate.

In the optical communication device according to the fourth aspect of the present invention, since the cap member is attached so as to cover the IC chip mounting substrate, it is between the IC chip mounting substrate and the surface on which the IC chip mounting substrate is mounted. There is no gap open to the outside, and no dust or foreign matter enters the optical path for optical signal transmission. Therefore, the transmission of optical signals is hindered due to the presence of such dust. There is nothing.
Therefore, the optical communication device of the fourth aspect of the present invention is excellent in reliability.

The optical communication device of the fourth aspect of the present invention covers the entire IC chip mounting substrate in place of the IC chip mounting substrate sealing layer, as compared with the optical communication device of the third aspect of the present invention. Although the cap member is different from the optical communication device of the third aspect of the invention in that the cap member is attached, the other configurations are the same as those of the optical communication device of the third aspect of the invention. Accordingly, only the cap member will be described in detail here.

FIG. 9 is a cross-sectional view schematically showing an embodiment of the optical communication device of the fourth aspect of the present invention.
FIG. 9 shows an optical communication device 960 in which an IC chip mounting substrate 2920 on which a light receiving element 2939 is mounted and an IC chip mounting substrate 1920 on which a light emitting element 1938 is mounted are mounted on a motherboard 920. Has been. In addition, as the IC chip mounting substrates 1920 and 2920, the IC chip mounting substrate of the second aspect of the present invention in which the IC chip is mounted is mounted.
The structure of the mother board 920 is the same as that of the mother board 720 already described. Therefore, the description thereof is omitted here.

The IC chip mounting substrate 1920 is formed by laminating a conductor circuit 1924 and an insulating layer 1922 on both surfaces of the substrate 1921. Between the conductor circuits sandwiching the substrate 1921 and between the conductor circuits sandwiching the insulating layer 1922, respectively. They are electrically connected through through holes (not shown) and via holes 1927. A solder resist layer 1934 is formed as the outermost layer.

In the IC chip mounting substrate 1920, an optical signal transmission optical path 1942 is provided so as to penetrate the substrate 1921, the insulating layer 1922, and the solder resist layer 1934. In this optical signal transmission optical path 1942, a resin composition 1947 is filled in a portion penetrating the substrate 1921 and the insulating layer 1922. In addition, the microlenses 1949 and 1946 are respectively provided on the side of the resin composition 1947 on which the light emitting element 1938 is mounted and on the opposite end thereof and through the solder resist layer of the optical signal transmission optical path 1942. Is arranged.

On one surface of the IC chip mounting substrate 1920, a light emitting element 1938 is surface-mounted via a solder connection portion 1944 so that the light emitting portion 1938a faces the optical path for optical signal transmission 1942.
In the IC chip mounting substrate 1920, a cap member 1918 is attached via an adhesive 1919 on the solder resist layer on one surface so as to cover the light emitting element 1938. Although not shown, an IC chip is mounted on the surface of the IC chip mounting substrate 1920 on the same side as the light emitting element 1938 on the surface via a solder connection portion.

In addition, the IC chip mounting substrate 2920 is formed by laminating a conductor circuit 2924 and an insulating layer 2922 on both surfaces of the substrate 2921. Between the conductor circuits sandwiching the substrate 2921 and between the conductor circuits sandwiching the insulating layer 2922, Each is electrically connected through a through hole (not shown) and a via hole 2927. A solder resist layer 2934 is formed on the outermost layer.

In the IC chip mounting substrate 2920, an optical signal transmission optical path 2942 is provided so as to penetrate the substrate 2921, the insulating layer 2922, and the solder resist layer 2934.
In this optical signal transmission optical path 2942, a resin composition 2947 is filled in a portion penetrating the substrate 2921 and the insulating layer 2922. In addition, each of the resin composition 2947 on the side where the light receiving element 2939 is mounted and the end on the opposite side of the resin composition 2947 that passes through the solder resist layer 2934 of the optical signal transmission optical path 2942 includes a microlens 2949, 2946 is provided.

On one surface of the IC chip mounting substrate 2920, a light receiving element 2939 is surface-mounted via a solder connection portion 2944 so that the light receiving portion 2939a faces the optical path for optical signal transmission 2942.
In the IC chip mounting substrate 2920, a cap member 2918 is attached via an adhesive 2919 on the solder resist layer on one surface so as to cover the light emitting element 2938. Although not shown, an IC chip is mounted on the surface of the IC chip mounting substrate 2920 on the same side as the light emitting element 2938 mounted via a solder connection portion.
The configuration of the mother board 920 is the same as that of the mother board 720.

In the optical communication device 960, IC chip mounting substrates 1920 and 2920 are mounted on the surface of the motherboard substrate 920 opposite to the side on which the optical waveguide 950 is formed via solder connection portions 1943 and 2943. Here, each of the IC chip mounting substrates 1920 and 2920 is mounted at a predetermined position by a self-alignment action.

Further, on the solder resist layer 734 on one surface, a cap member 918 is attached via an adhesive 919 so as to cover each of the IC chip mounting substrates 1920 and 2920. A gap is formed immediately below the optical signal transmission optical paths 1942 and 2942 formed on the IC chip mounting substrates 1920 and 2920, respectively.

By attaching the cap member 918 in this manner, dust or dirt is contained in the optical signal transmission optical path formed on the IC chip mounting substrate 1920 or 2920 or in the optical signal transmission optical path 742 formed on the motherboard substrate. Foreign matter or the like does not enter, and transmission of optical signals is not hindered by the dust or foreign matter.

In the optical communication device 960 having such a configuration, an electrical signal from an IC chip (not shown) mounted on the IC chip mounting substrate 1920 is converted into an optical signal by the light emitting element 1938, and the light emitting element 1938 ( The optical signal emitted from the light emitting unit 1938a) is a micro lens 1949, an optical signal transmission optical path 1942, a micro lens 1946, a micro lens 946a, an optical signal transmission optical path 942, an optical waveguide 950, an optical signal transmission optical path 942, and a micro lens. 946b, the micro lens 946, the optical signal transmission optical path 2942, and the micro lens 2949, the light is transmitted to the light receiving element 2939 (light receiving unit 2939a) and further converted into an electric signal by the light receiving element 2939, and then the IC chip mounting substrate 2920. Transmitted to an IC chip (not shown) mounted on the It is the thing.
In such an optical communication device, an optical signal is transmitted through the microlens disposed at the end of the resin composition, so that the optical signal can be reliably transmitted.

The material, shape, and the like of the cap member are not particularly limited, and examples of the material include ceramic, resin, metal, glass, and the like, among which resin is desirable. Moreover, the shape of a cap member should just be a shape which can cover the said optical elements, such as a U-shaped cross section. Specific examples include a ceramic cap with a sealant and a resin cap with an adhesive.
Note that the resin cap member can be manufactured by subjecting a plate-shaped material substrate to a counterbore process and then a dicing process. Further, metal plating (Ni / Au plating) may be applied to the outer upper surface of the cap member. This is because reliability can be improved.

In the optical communication device shown in FIG. 9, the cap member is attached to the solder resist layer via an adhesive (resin). However, in the optical communication device according to the fourth aspect of the present invention, the cap member is soldered. It may be attached to a portion where the solder resist layer is not formed. However, when a cap member is attached via solder, a pad is required on the outermost layer, which places restrictions on the design of the conductor circuit and further requires a separate process for solder shielding. The cap member is desirably attached via an adhesive (resin). In addition, also when attaching a cap member via an adhesive agent (resin), the reliability equivalent to the case where it attaches via solder can be acquired.

Further, in the optical communication device shown in FIG. 9, the cap member is attached so as to separately cover each of the mounted IC chip mounting substrates, but in the optical communication device of the fourth aspect of the present invention, The embodiment in which the cap member is attached is not limited to such a form.
Specifically, the cap member may be attached so that all of the plurality of IC chip mounting substrates are covered with one cap member. Further, a cap member may be attached so as to simultaneously cover various surface mountings other than the IC chip mounting substrate mounted on the motherboard.

In the optical communication device shown in FIG. 9, the IC chip mounting substrate of the second aspect of the present invention, in which a cap member is attached so as to cover the optical element, is mounted as the IC chip mounting substrate. In the optical communication device according to the fourth aspect of the present invention, the IC chip mounting substrate mounted on the motherboard for the mother board is not limited to the IC chip mounting substrate according to the second aspect of the present invention. It may be the IC chip mounting substrate of the first aspect of the present invention in which the optical element sealing layer is formed so as to be in contact, or the IC chip mounting substrate of the third embodiment.

Further, it may be an IC chip mounting substrate on which neither a conventionally known optical element sealing layer is formed nor a cap member is attached. In other words, the entire IC chip mounting substrate on which the optical element is mounted may be covered with a single cap member.
Usually, it is desirable to mount the drive IC connected adjacent to the optical element as close as possible to the optical element, and it is also necessary to mount a resistor, a capacitor, and the like on the IC chip mounting substrate. Furthermore, miniaturization of the IC chip mounting substrate is also required. In consideration of these points, the entire IC chip mounting substrate is covered without covering the optical element with the cap member, rather than covering only the optical element with the cap member and again covering the IC chip mounting substrate with the cap member. It may be desirable to have a configuration in which one is covered with a cap member.

Note that, as described above, the constituent members other than the cap member constituting the optical communication device are the same as the constituent members of the optical communication device of the third aspect of the present invention, so that the description thereof is omitted.

The optical communication device according to the fourth aspect of the present invention that has been described so far has a substrate and an insulating layer made of a resin material.
However, even when the substrate, the insulating layer, or the like is made of a material other than resin, for example, glass or ceramic, the same effect as the fourth aspect of the present invention can be obtained.
In other words, an IC chip mounting substrate on which an optical element is mounted on a wiring board made of glass or ceramic is mounted on a motherboard substrate on which an optical waveguide is formed on a wiring board made of glass or ceramic. At least the IC chip mounting Even in the optical communication device to which the cap member is attached so as to cover the optical substrate, the same effect as the optical communication device of the fourth aspect of the present invention described above can be obtained. The same applies to the case where only one of the IC chip mounting substrate and the motherboard substrate is made of glass, ceramic, or the like.

Next, a method for manufacturing the optical communication device of the fourth aspect of the present invention will be described.
In the step of manufacturing the optical communication device of the third aspect of the present invention, the IC chip mounting substrate sealing layer is covered with the following method without forming the IC chip mounting substrate sealing layer. Thus, it can manufacture using the method substantially the same as the method of manufacturing the device for optical communication of 3rd this invention except attaching a cap member.

As a method of attaching the cap member so as to cover the IC chip mounting substrate, for example, after applying an uncured resin composition to a predetermined portion of the cap member or a predetermined portion of the surface of the motherboard substrate in advance, The uncured resin composition is cured to the B stage to temporarily fix the cap member, and thereafter, a weight is placed on the cap member, or the cap member is fixed with a jig such as a clip to 1 to 1000 g. A cap member can be attached by applying a load of / cm ² and curing the resin composition in an oven in this state.
Also, after pasting a B stage resin film on a predetermined portion of the cap member or a predetermined portion of the solder resist layer in advance, the cap member is temporarily fixed by applying heat to the resin film, and then the cap member. A weight of 1-1000 g / cm ² is applied by placing a weight on the cap or fixing the cap member with a jig such as a clip, and the cap member is attached by curing the resin film in the oven in this state. You can also.
In addition, a solder paste is applied in advance to a predetermined portion of the cap member or a predetermined portion on the outermost insulating layer, the cap member is disposed at a predetermined position, and the cap member is attached by performing a reflow process. A method can also be used.

Further, when a cap member is attached using such a method, the cap member may be attached so as to cover only one IC chip mounting substrate, or a plurality of IC chip mounting substrates may be integrated. The cap member may be attached so as to cover, or in some cases, the cap member may be attached so as to integrally cover one or a plurality of IC chip mounting substrates and other surface mounting components.

Moreover, the adhesive used when attaching the cap member is desirably an adhesive that does not spread during curing from the viewpoint of reliability. Therefore, in the optical communication device of the third aspect of the present invention, it is desirable to use a resin composition having the same characteristics as the resin used when forming the IC chip mounting substrate sealing layer.

Further, in the manufacture of the optical communication device of the fourth aspect of the present invention, when mounting an IC chip mounting substrate or various surface mounting components located inside the cap member via solder bumps, the above IC chip mounting It is desirable to perform flux cleaning after mounting a substrate or the like. If the flux cleaning is not performed after mounting the IC chip mounting board, etc., after manufacturing the optical communication device, the flux component solidifies and peels off, and enters the optical path for optical signal transmission as a foreign substance. This is because signal transmission loss may increase or an optical signal may not be transmitted.
By using such a method, the IC chip mounting substrate of the fourth aspect of the present invention can be manufactured.

Further, instead of attaching the cap member constituting the optical communication device of the fourth invention, a dam frame is formed on the lower surface of the IC chip mounting substrate (the surface facing the motherboard substrate). The optical communication device in which the IC chip mounting substrate on which the dam frame is formed is mounted on the motherboard substrate also has the same effect as the optical communication device of the fourth aspect of the present invention.
That is, an IC chip mounting in which an optical element is mounted on a motherboard substrate on which a conductor circuit and an insulating layer are laminated and formed on at least one side of the substrate, an optical waveguide is formed, and an optical path for optical signal transmission is further formed An optical communication device on which a circuit board is mounted,
The optical communication device in which the dam frame is formed on the lower surface of the IC chip mounting substrate, as well as the optical communication device according to the fourth aspect of the present invention, has dust or foreign matter entering the optical signal transmission optical path. Therefore, the transmission of the optical signal is not hindered due to the presence of the dust and the like. Therefore, the optical communication device having such a configuration is also excellent in reliability.

The optical communication device having such a configuration can be manufactured by the following method.
That is, first, after manufacturing an IC chip mounting substrate, a dam frame made of glass-epoxy resin or the like is pasted on its lower surface via an adhesive, and then IC chip mounting with this dam frame is mounted. The dam frame can be formed by resin-sealing after mounting the substrate for mounting on the motherboard substrate and performing flux cleaning.

Here, the resin sealing is performed by applying a resin around the dam frame with a dispenser, then curing to the resin B stage, and then fully curing the resin while applying a load from the upper side of the IC chip mounting substrate. A method or the like can be used.
Examples of the mounting method for the IC chip mounting substrate include cream solder printing, mounting by reflow using bond flux, mounting by a heat tool method using a high-precision flip chip mounting machine, and the like.
Note that flux cleaning is required for mounting by the reflow method, whereas fluxless mounting is possible for mounting by the heat tool method, so that the optical signal transmission is not hindered by the flux, and the IC chip. It is preferable in that the mounting substrate can be mounted and the dam can be sealed at the same time.

Hereinafter, the present invention will be described in more detail.
Example 1
A. Production of resin film for insulating layer 30 parts by weight of bisphenol A type epoxy resin (epoxy equivalent 469, Epicoat 1001 manufactured by Yuka Shell Epoxy), cresol novolac type epoxy resin (epoxy equivalent 215, manufactured by Dainippon Ink & Chemicals, Inc., Epicron N- 673) 40 parts by weight, triazine structure-containing phenol novolak resin (phenolic hydroxyl group equivalent 120, Phenolite KA-7052 manufactured by Dainippon Ink & Chemicals, Inc.) in 20 parts by weight of ethyl diglycol acetate and 20 parts by weight of solvent naphtha It is dissolved by heating with stirring, and 15 parts by weight of terminal epoxidized polybutadiene rubber (Denalex R-45EPT, manufactured by Nagase Kasei Kogyo Co., Ltd.) and 1.5 parts by weight of pulverized 2-phenyl-4,5-bis (hydroxymethyl) imidazole , Finely ground siri 2 parts by weight, the addition of silicone 0.5 part by weight defoaming agent to prepare an epoxy resin composition.
The obtained epoxy resin composition was coated on a PET film having a thickness of 38 μm using a roll coater so that the thickness after drying was 50 μm, and then dried at 80 to 120 ° C. for 10 minutes, whereby an insulating layer was obtained. A resin film was prepared.

B. Preparation of resin composition for filling through-hole 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell Co., Ltd., molecular weight: 310, YL983U), the average particle diameter coated with a silane coupling agent is 1.6 μm, By taking 170 parts by weight of SiO ₂ spherical particles having a maximum particle diameter of 15 μm or less (manufactured by Adtech, CRS 1101-CE) and 1.5 parts by weight of a leveling agent (Senopco Perenol S4) in a container, and stirring and mixing, A resin filler having a viscosity of 45 to 49 Pa · s at 23 ± 1 ° C. was prepared. As the curing agent, 6.5 parts by weight of an imidazole curing agent (manufactured by Shikoku Kasei Co., Ltd., 2E4MZ-CN) was used.

C. Manufacture of IC chip mounting substrate (1) Copper-clad laminate in which 18 μm copper foil 28 is laminated on both sides of insulating substrate 21 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 0.8 mm As a starting material (see FIG. 10A). First, the copper-clad laminate was drilled, subjected to electroless plating, and etched into a pattern to form conductor circuits 24 and through holes 29 on both surfaces of the substrate 21.

(2) An aqueous solution containing NaOH (10 g / l), NaClO ₂ (40 g / l), and Na ₃ PO ₄ (6 g / l) after washing and drying the substrate on which the through hole 29 and the conductor circuit 24 are formed. Conductive circuit including through-hole 29 by performing blackening treatment using as a blackening bath (oxidation bath) and reduction treatment using an aqueous solution containing NaOH (10 g / l) and NaBH ₄ (6 g / l) as a reducing bath A roughened surface (not shown) was formed on the surface of 24 (see FIG. 10B).

(3) After preparing the resin filler described in B above, within 24 hours after preparation by the following method, the conductor circuit non-formed part on one side of the through hole 29 and the substrate 21 and the outer edge part of the conductor circuit 24 A layer of resin filler 30 'was formed on the substrate.
That is, first, a resin filler was pushed into a through hole using a squeegee, and then dried under conditions of 100 ° C. and 20 minutes. Next, a mask having an opening corresponding to the conductor circuit non-formed part is placed on the substrate, and the conductor circuit non-formed part which is a recess is filled with a resin filler using a squeegee, A layer of a resin filler 30 'was formed by drying for 20 minutes (see FIG. 10C).

(4) The surface of the conductor circuit 24 or the land surface of the through hole 29 is applied to one surface of the substrate after the processing of (3) by belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku Co., Ltd.). Polishing was performed so that the resin filler 30 'did not remain, and then buffing was performed to remove scratches due to the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate.
Subsequently, the heat processing of 100 degreeC for 1 hour, 120 degreeC for 3 hours, 150 degreeC for 1 hour, and 180 degreeC for 7 hours was performed, and the resin filler layer 30 was formed.

In this way, the surface layer portion of the resin filler 30 and the surface of the conductor circuit 24 formed in the through hole 29 and the conductor circuit non-forming portion are flattened, and the resin filler 30 and the side surface of the conductor circuit 24 are roughened. An insulating substrate was obtained in which the inner wall surface of the through hole 29 and the resin filler 30 were firmly adhered via a roughened surface (not shown) (not shown). (Refer FIG.10 (d)). By this step, the surface of the resin filler layer 30 and the surface of the conductor circuit 24 are flush with each other.

(5) The substrate is washed with water, acid degreased, soft-etched, and then an etching solution is sprayed onto both surfaces of the substrate to etch the surface of the conductor circuit 24, the land surface of the through hole 29, and the inner wall. Thus, a roughened surface (not shown) was formed on the entire surface of the conductor circuit 24. As an etching solution, an etching solution containing 10 parts by weight of imidazole copper (II) complex, 7 parts by weight of glycolic acid, and 5 parts by weight of potassium chloride (MEC Etch Bond, manufactured by MEC) was used.

(6) Next, a resin film for an insulating layer that is slightly larger than the substrate prepared in A is placed on the substrate, and is temporarily crimped under conditions of a pressure of 0.4 MPa, a temperature of 80 ° C., and a crimping time of 10 seconds and cut. After that, the insulating layer 22 was further formed by pasting using a vacuum laminator apparatus by the following method (see FIG. 10E).
That is, the insulating layer resin film was subjected to main pressure bonding on the substrate under the conditions of a degree of vacuum of 65 Pa, a pressure of 0.4 MPa, a temperature of 80 ° C., and a time of 60 seconds, and then thermally cured at 170 ° C. for 30 minutes.

(7) Next, a beam diameter of 4.0 mm, top hat mode, with a CO ₂ gas laser with a wavelength of 10.4 μm through a mask in which a through hole having a thickness of 1.2 mm is formed on the insulating layer 22. A via hole opening 26 having a diameter of 80 μm was formed in the insulating layer 22 under the conditions of a pulse width of 8.0 μs, a through hole diameter of the mask of 1.0 mm, and one shot (see FIG. 11A).

(8) By immersing the substrate on which the via hole opening 26 is formed in an 80 ° C. solution containing 60 g / l permanganic acid for 10 minutes to dissolve and remove the epoxy resin particles present on the surface of the insulating layer 22 A roughened surface (not shown) was formed on the surface including the inner wall surface of the via hole opening 26.

(9) Next, the substrate after the above treatment was immersed in a neutralization solution (manufactured by Shipley Co., Ltd.) and washed with water.
Furthermore, a catalyst catalyst is attached to the surface of the insulating layer 22 (including the inner wall surface of the via hole opening 26) by applying a palladium catalyst to the surface of the substrate that has been roughened (roughening depth 3 μm). (Not shown). That is, the substrate was immersed in a catalyst solution containing palladium chloride (PdCl ₂ ) and stannous chloride (SnCl ₂ ), and the catalyst was applied by depositing palladium metal.

(10) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition, and the thickness of the insulating layer 22 (including the inner wall surface of the via hole opening 26) is 0.6 to 3.0 μm. A thin film conductor layer (electroless copper plating film) 32 was formed (see FIG. 11B).
[Electroless plating aqueous solution]
NiSO ₄ 0.003 mol / l
Tartaric acid 0.200 mol / l
Copper sulfate 0.030 mol / l
HCHO 0.050 mol / l
NaOH 0.100 mol / l
α, α'-bipyridyl 100 mg / l
Polyethylene glycol (PEG) 0.10 g / l
[Electroless plating conditions]
40 minutes at a liquid temperature of 30 ° C

(11) Next, a commercially available photosensitive dry film is attached to the substrate on which the thin film conductor layer (electroless copper plating film) 32 is formed, a mask is placed, and exposure is performed at 100 mJ / cm ^2. A plating resist 23 having a thickness of 20 μm was provided by developing with a% sodium carbonate aqueous solution (see FIG. 11C).

(12) Next, the substrate is washed with 50 ° C. water, degreased, washed with 25 ° C. water, and further washed with sulfuric acid. Then, an electrolytic copper plating film 33 having a thickness of 20 μm was formed (see FIG. 11D).
[Electrolytic plating solution]
Sulfuric acid 2.24 mol / l
Copper sulfate 0.26 mol / l
Additive 19.5 ml / l
(Manufactured by Atotech Japan, Kaparaside HL)
[Electrolytic plating conditions]
Current density 1 A / dm ²
Time 65 minutes Temperature 22 ± 2 ℃

(13) Further, after removing the plating resist 23 with 5% NaOH, the thin film conductor layer under the plating resist 23 is removed by dissolution with a mixed solution of sulfuric acid and hydrogen peroxide to remove the thin film conductor layer ( A conductor circuit 24 (including via hole 27) having a thickness of 18 μm made of electroless copper plating film 32 and electrolytic copper plating film 33 was formed (see FIG. 12A).

(14) Further, a roughened surface (not shown) is formed on the surface of the conductor circuit 24 using the same etching solution as the etching solution used in the step (5). In the same manner as in the step (8), an insulating layer 22 having a via hole opening 26 and having a roughened surface (not shown) formed on the surface thereof was laminated (see FIG. 12B).
Thereafter, a through hole 46 penetrating the substrate 21 and the insulating layer 22 was formed using a drill having a diameter of 350 μm, and further, a desmear process was performed on the wall surface of the through hole 46 (see FIG. 12C).

(15) Next, a catalyst was applied to the wall surface of the through hole 46 and the surface of the insulating layer 22 in the same manner as in the step (9), and the catalyst was further used in the step (10). The substrate is immersed in an electroless copper plating aqueous solution similar to the electroless plating solution, and a thin film conductor layer (on the surface of the insulating layer 22 (including the inner wall surface of the via hole opening 26) and the wall surface of the through hole 46 is formed. An electroless copper plating film) 32 was formed (see FIG. 13A).

(16) Next, a plating resist 23 is provided by a method similar to the method used in the step (11), and the plating resist 23 non-coated by a method similar to the method used in the step (12). An electrolytic copper plating film 33 having a thickness of 20 μm was formed on the formation part (see FIG. 13B).

(17) Next, the plating resist 23 is peeled off and the thin film conductor layer under the plating resist 23 is removed by a method similar to the method used in the step (13), and the conductor circuit 24 (via hole 27) is removed. And a conductor layer 45 were formed.
Further, oxidation / reduction treatment was performed by the same method as used in the step (2) above, and the surface of the conductor circuit 24 and the surface of the conductor layer 45 were roughened (not shown) (FIG. 13 ( c)).

(18) Next, the resin composition is placed on a hole-filling mask of a printing press and screen printing is performed to fill the resin in the through hole for an optical path, and then at 120 ° C. for 1 hour and at 150 ° C. for 1 hour. Then, the resin protruding from the optical path through hole 81 is polished with # 3000 abrasive paper, and further polished with 0.05 μm alumina particles to flatten the surface. As a result, the resin composition layer 47 was formed.
In this step, as the resin composition, 40% by weight of pulverized silica having a particle size distribution of 0.1 to 0.8 μm is added to an epoxy resin (transmittance 91% / mm, CTE 82 ppm), and the transmittance 82% / mm, CTE 42 ppm, and a particle size adjusted to 200000 cps was used (see FIG. 14A).

(19) Next, a solder resist composition (RPZ-1 manufactured by Hitachi Chemical Co., Ltd.) is applied to both sides of the substrate on which the resin composition layer 47 has been formed in a thickness of 30 μm, and 70 ° C. for 20 minutes at 70 ° C. A drying process was performed for 30 minutes to form a solder resist composition layer 34 '. (See FIG. 14 (b)).

(20) Next, a photomask having a thickness of 5 mm on which patterns of openings for forming solder bumps and openings for optical paths are drawn is brought into close contact with the layer 34 'of the solder resist composition on the IC chip mounting side, and 1000 mJ / cm ² of ultraviolet light is applied. And developed with a DMTG solution to form openings with a diameter of 200 μm.
Further, the solder resist composition layer is cured by heating at 80 ° C. for 1 hour, at 100 ° C. for 1 hour, at 120 ° C. for 1 hour, and at 150 ° C. for 3 hours, respectively. The solder resist layer 34 having an optical path opening 42b and a thickness of 20 μm was formed (see FIG. 15A).
In addition, as said solder resist composition, a commercially available solder resist composition can also be used.

(21) Next, the substrate on which the solder resist layer 34 is formed is made of nickel chloride (2.3 × 10 ⁻¹ mol / l), sodium hypophosphite (2.8 × 10 ⁻¹ mol / l), A nickel plating layer having a thickness of 5 μm is formed in the solder bump forming opening 47 by immersing in an electroless nickel plating solution containing sodium acid (1.6 × 10 ⁻¹ mol / l) at pH = 4.5 for 20 minutes. did. Furthermore, the substrate gold potassium cyanide ^{(7.6 × 10 -3 mol / l} ), ammonium chloride ^{(1.9 × 10 -1 mol / l} ), sodium citrate (1.2 × ¹⁰ -1 mol / l) Immerse in an electroless gold plating solution containing sodium hypophosphite (1.7 × 10 ⁻¹ mol / l) at 80 ° C. for 7.5 minutes to form a thickness of 0 on the nickel plating layer. A 0.03 μm gold plating layer was formed to form solder pads 36.

(22) Next, a fluorine-based polymer water-repellent coating agent (EGC-1700 manufactured by Sumitomo 3M) is spray-coated on the entire surface of the solder resist layer on the side where the microlens is disposed, and after air blowing, Surface treatment was applied by natural drying.
Further, the microlens 46 is attached to the end of the resin composition layer 47 opposite to the side on which the optical element is mounted using an ink jet device in the optical path opening formed in the solder resist layer 34 by the following method. Arranged.
That is, after preparing a UV curable epoxy resin (transmittance 94% / mm, refractive index 1.53) at room temperature (25 ° C.) and a viscosity of 20 cps, the resin is heated in a resin container of an ink jet apparatus. The temperature was adjusted to 40 ° C. and the viscosity was adjusted to 8 cps. Thereafter, the resin composition layer 47 was applied to a predetermined position at the end of the resin composition layer 47 so as to form a hemisphere having a diameter of 220 μm and a sag height of 10 μm. The microlens 46 was disposed by curing the resin by irradiation.

(23) Next, a solder paste is printed in the solder bump forming opening 47 formed in the solder resist layer 34, and further, the light receiving portions 39a and the light emitting portions 39a of the light receiving element 39 and the light emitting element 38 are positioned while being aligned. By reflowing at 200 ° C., the light receiving element 39 and the light emitting element 38 were mounted, and solder bumps 37 were formed in the solder bump forming openings 47 (see FIG. 15B).
The light emitting element 38 is a flip chip type VCSEL, and the light receiving element 39 is a flip chip type PINPD.

(24) Next, an optical element sealing layer was formed by using the following method so as to be in contact with the outer circumferences of the light receiving element 39 and the light emitting element 38, and an IC chip mounting substrate was manufactured (see FIG. 16). .
That is, 75 wt% spherical silica having a particle size distribution of 1 to 100 μm and an average particle size of 25 μm is added to an epoxy resin, and a resin composition having a CTE of 20 ppm, a viscosity of 250 Pa · s, and a thixo ratio of 1.7 is received by botting. After applying so as to be in contact with the outer periphery of each of the element 39 and the light emitting element 38, the optical element sealing layer was formed by performing a curing treatment at 150 ° C. for 2 hours.

In the IC chip mounting substrate manufactured in this example, the distance between the bottom surface of the optical element and the surface of the solder resist layer is 50 μm.
Further, in the IC chip mounting substrate of this embodiment, a gap is formed in a portion of the optical signal transmission optical path in contact with the optical element. Therefore, the optical element sealing layer is not formed on the portion of the optical signal transmission optical path that is in contact with the optical element.

(Example 2)
After the step (22) of Example 1 and before performing the step (23), the following method is used to place a non-deposited position on the solder resist layer (around the optical element sealing layer to be formed later). Form a dam to stop the flow of the curing optical element sealing resin, and then apply a commercially available underfill resin (CCN800D, manufactured by Kyushu Matsushita Electric Co., Ltd.) around the optical element with a dispenser, and then cure An IC chip mounting substrate was manufactured in the same manner as in Example 1 except that the optical element sealing layer was formed by processing.
The dam was formed by silk-printing an epoxy resin and then performing a curing process.

(Example 3)
After performing the step (23) without performing the step (24) of Example 1, using the following method, except that a cap member that covers each of the light receiving element and the light emitting element was attached, An IC chip mounting substrate was manufactured in the same manner as in Example 1.
First, the entire surface of one side of the double-sided copper-clad glass epoxy substrate is etched, and then the electrolytic Ni / Au layer (Ni 5 μm, Au 0.5 μm is applied to the copper side. A member was prepared.
Next, a resin composition in which 70% by weight of spherical silica having a particle size distribution of 1 to 30 μm and an average particle size of 4 μm is added to an epoxy resin at a position where a cap member is attached (viscosity 200 Pa · s, thixo ratio 1.8, CTE 30 ppm) ) Was applied with a dispenser and cured to the B stage in an oven.
Thereafter, the cap member is temporarily fixed while being aligned on a substrate with a flip chip mounting machine, a weight of ² g / mm ² is placed on the cap member, and the resin composition is cured in an oven to cap the cap. The member was attached.

(Comparative Example 1)
An IC chip mounting substrate was manufactured in the same manner as in Example 1 except that the step (24) of Example 1, that is, the optical element sealing layer was not formed.

The optical signal transmission ability of the IC chip mounting substrates according to the examples and comparative examples was evaluated by the following method.
First, an IC chip is mounted on an IC chip mounting substrate (see FIG. 16), and then a detector is attached to the end of the optical signal transmission optical path of the IC chip mounting substrate opposite to the light emitting element mounting side. An optical signal was transmitted from the element, and the optical signal was detected by a detector. As a result, a desired optical signal could be detected.

Next, the IC chip mounting substrates according to the example and the comparative example on which the IC chip was mounted were left in an environment where relatively dust is generated, and then transported in a box. Thereafter, the optical signal transmission ability of the IC chip mounting substrate was evaluated using the method described above. As a result, the IC chip mounting substrate according to the example was able to transmit an optical signal as before being left in an environment where dust was generated. On the other hand, some IC chip mounting substrates according to the comparative example cannot transmit optical signals. This is presumably because dust has entered the optical path for optical signal transmission.

Further, in Example 3, when a cap member made of ceramic is used instead of a cap member made of a resin material, and when the cap member is attached via solder instead of an adhesive, the same as in Example 3 Results were obtained. Here, in order to attach the cap member via solder, a pad was previously formed on the outermost insulating layer, and no solder resist layer was formed on this portion.
In addition, in the IC chip mounting substrates according to the first to third embodiments, a 1-channel light-emitting element and a light-receiving element are mounted as optical elements, respectively. Instead of these optical elements, a 4-channel light-emitting element and a light-receiving element are mounted. Similar results were obtained with an IC chip mounting substrate in which elements were mounted and the cross-sectional size of the optical path for optical signal transmission was increased accordingly.

Further, in the IC chip mounting substrate of the first aspect of the present invention, there can be a gap between the optical element and the solder resist layer. There is a concern that cracks may occur in the optical element sealing layer or the like. Therefore, the following Test Examples 1 to 5 are performed, and the influence due to the difference in the portion where the optical element sealing layer is formed is affected by the optical waveguide, the solder connection portion, the solder resist layer, the insulating layer, etc. after the liquid phase temperature cycle test. The presence or absence of cracks was evaluated as an index.

(Test Example 1)
Basically, an IC chip mounting substrate was manufactured in the same manner as in Example 1. However, when the optical element sealing layer was formed, the optical element sealing layer was formed so that the sealing resin layer was present only on the outside of the solder bumps.

(Test Example 2)
Basically, an IC chip mounting substrate was manufactured in the same manner as in Example 1. However, when the optical element sealing layer was formed, the optical element sealing layer was formed so that the sealing resin layer was also present inside the solder bumps and the solder bumps were buried in the sealing resin layer.

(Test Example 3)
Basically, an IC chip mounting substrate was manufactured in the same manner as in Example 1. However, when the optical element sealing layer is formed, the sealing resin layer also exists inside the solder bump, and the solder bump is buried in the sealing resin layer and only outside the solder bump. The optical element sealing layer was formed so as to be mixed with the portion where the sealing resin layer was formed.

(Test Example 4)
An IC chip mounting substrate was manufactured in the same manner as in Comparative Example 1. That is, the optical element sealing layer was not formed.

(Test Example 5)
Basically, an IC chip mounting substrate was manufactured in the same manner as in Example 1. However, in place of the optical element sealing layer, an underfill was formed between the optical element and the solder resist layer.

For the IC chip mounting substrates according to these test examples 1 to 5, a liquid phase temperature cycle test in which one cycle is 3 minutes at −55 ° C. and 3 minutes at 125 ° C. is for mounting five IC chips. For the substrate, 0 cycle, 250 cycle, 500 cycle and 1000 cycle are performed, and then the IC chip mounting substrate is cross-cut. Further, the solder connection section cross section, the sealing resin layer cross section, the substrate cross section, the insulating layer cross section, the solder It was observed with a microscope whether cracks occurred in the resist layer cross section and the optical element cross section.
As a result, no crack was observed in any of the IC chip mounting substrates.

Therefore, in the IC chip mounting substrate of the first aspect of the present invention, by forming the optical element sealing layer, the portion between the optical element and the solder resist layer (the portion in contact with the optical element in the optical path for optical signal transmission) It has been clarified that even if a gap is formed in (), the IC chip mounting substrate is not adversely affected.

Example 4
A. Production of Resin Film for Insulating Layer A resin film for an insulating layer was produced in the same manner as in Step A of Example 1.
B. Preparation of resin composition for filling through-hole The resin composition for filling through-hole was prepared in the same manner as in Step B of Example 1.

C. Manufacture of Mother Board Substrate (1) Starting from a copper clad laminate in which 18 μm copper foil 78 is laminated on both sides of an insulating substrate 71 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 0.8 mm The material was used (see FIG. 17A). First, the copper-clad laminate was drilled, subjected to electroless plating, and etched into a pattern to form conductor circuits 74 and through holes 79 on both surfaces of the substrate 71.

(2) An aqueous solution containing NaOH (10 g / l), NaClO ₂ (40 g / l), and Na ₃ PO ₄ (6 g / l) after washing and drying the substrate on which the through hole 79 and the conductor circuit 74 are formed. Conductor circuit including through-hole 79 by performing blackening treatment using as a blackening bath (oxidation bath) and reduction treatment using an aqueous solution containing NaOH (10 g / l) and NaBH ₄ (6 g / l) as a reducing bath A roughened surface (not shown) was formed on the surface of 74 (see FIG. 17B).

(3) After preparing the resin filler described in B above, within 24 hours after preparation by the following method, the conductor circuit non-formed portion on the one side of the through hole 79 and the substrate 71 and the outer edge portion of the conductor circuit 74 A layer of resin filler 80 'was formed.
That is, first, a resin filler was pushed into a through hole using a squeegee, and then dried under conditions of 100 ° C. and 20 minutes. Next, a mask having an opening corresponding to the conductor circuit non-formed part is placed on the substrate, and the conductor circuit non-formed part which is a recess is filled with a resin filler using a squeegee, A layer of the resin filler 80 'was formed by drying for 20 minutes (see FIG. 17C).

(4) One side of the substrate after the processing in (3) above is applied to the surface of the conductor circuit 74 and the land surface of the through hole 79 by belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku). Polishing was performed so as not to leave the resin filler 80 ', and then buffing was performed to remove scratches caused by the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate.
Next, heat treatment was performed at 100 ° C. for 1 hour, 120 ° C. for 3 hours, 150 ° C. for 1 hour, and 180 ° C. for 7 hours to form a resin filler layer 80.

In this way, the surface layer portion of the resin filler 80 and the surface of the conductor circuit 74 formed in the through hole 79 and the conductor circuit non-forming portion are flattened, and the resin filler 80 and the side surface of the conductor circuit 74 are roughened. An insulating substrate was obtained in which the inner wall surface of the through hole 79 and the resin filler 80 were firmly adhered via a roughened surface (not shown) (not shown). (Refer FIG.17 (d)). By this step, the surface of the resin filler layer 80 and the surface of the conductor circuit 74 are flush.

(5) After washing the substrate with water and acid degreasing, soft etching is performed, and then an etching solution is sprayed on both surfaces of the substrate to spray the surface of the conductor circuit 74, the land surface of the through hole 79, and the inner wall. Thus, a roughened surface (not shown) was formed on the entire surface of the conductor circuit 74. As an etching solution, an etching solution containing 10 parts by weight of imidazole copper (II) complex, 7 parts by weight of glycolic acid, and 5 parts by weight of potassium chloride (MEC Etch Bond, manufactured by MEC) was used.

(6) Next, a resin film for an insulating layer that is slightly larger than the substrate prepared in A is placed on the substrate and cut by temporary pressure bonding under conditions of a pressure of 0.4 MPa, a temperature of 80 ° C., and a pressure bonding time of 10 seconds. After that, the insulating layer 72 was further formed by pasting using a vacuum laminator apparatus by the following method (see FIG. 17E).
That is, the insulating layer resin film was subjected to main pressure bonding on the substrate under the conditions of a degree of vacuum of 65 Pa, a pressure of 0.4 MPa, a temperature of 80 ° C., and a time of 60 seconds, and then thermally cured at 170 ° C. for 30 minutes.

(7) Next, a beam diameter of 4.0 mm, a top hat mode, with a CO ₂ gas laser having a wavelength of 10.4 μm, through a mask in which a through hole having a thickness of 1.2 mm is formed on the insulating layer 72. A via hole opening 76 having a diameter of 80 μm was formed in the insulating layer 72 under the conditions of a pulse width of 8.0 μsec, a through-hole diameter of the mask of 1.0 mm, and one shot (see FIG. 18A).

(8) By immersing the substrate on which the via hole opening 76 is formed in an 80 ° C. solution containing 60 g / l of permanganic acid for 10 minutes, and dissolving and removing the epoxy resin particles present on the surface of the insulating layer 72 A roughened surface (not shown) was formed on the surface including the inner wall surface of the via hole opening 76.

(9) Next, the substrate after the above treatment was immersed in a neutralization solution (manufactured by Shipley Co., Ltd.) and washed with water.
Furthermore, a catalyst catalyst is attached to the surface of the insulating layer 72 (including the inner wall surface of the via hole opening 76) by applying a palladium catalyst to the surface of the roughened substrate (roughening depth 3 μm). (Not shown). That is, the substrate was immersed in a catalyst solution containing palladium chloride (PdCl ₂ ) and stannous chloride (SnCl ₂ ), and the catalyst was applied by depositing palladium metal.

(10) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition, and the thickness of the insulating layer 72 (including the inner wall surface of the via hole opening 76) is 0.6 to 3.0 μm. A thin film conductor layer (electroless copper plating film) 72 was formed (see FIG. 18B).
[Electroless plating aqueous solution]
NiSO ₄ 0.003 mol / l
Tartaric acid 0.200 mol / l
Copper sulfate 0.030 mol / l
HCHO 0.050 mol / l
NaOH 0.100 mol / l
α, α'-bipyridyl 100 mg / l
Polyethylene glycol (PEG) 0.10 g / l
[Electroless plating conditions]
40 minutes at a liquid temperature of 30 ° C

(11) Next, a commercially available photosensitive dry film is attached to the substrate on which the thin film conductor layer (electroless copper plating film) 82 is formed, a mask is placed, and exposure is performed at 100 mJ / cm ^2. A plating resist 73 having a thickness of 20 μm was provided by developing with a% sodium carbonate aqueous solution (see FIG. 18C).

(12) Next, the substrate is washed with 50 ° C. water, degreased, washed with 25 ° C. water and further washed with sulfuric acid, and then subjected to electrolytic plating under the following conditions to form a plating resist 73 non-formed portion. Then, an electrolytic copper plating film 83 having a thickness of 20 μm was formed (see FIG. 18D).
[Electrolytic plating solution]
Sulfuric acid 2.24 mol / l
Copper sulfate 0.26 mol / l
Additive 19.5 ml / l
(Manufactured by Atotech Japan, Kaparaside HL)
[Electrolytic plating conditions]
Current density 1 A / dm ²
Time 65 minutes Temperature 22 ± 2 ℃

(13) Further, after removing the plating resist 73 with 5% NaOH, the thin film conductor layer under the plating resist 73 is dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide. A conductor circuit 74 (including a via hole 77) having a thickness of 18 μm composed of an electroless copper plating film 82 and an electrolytic copper plating film 83 was formed (see FIG. 19A).

(14) Furthermore, a roughened surface (not shown) is formed on the surface of the conductor circuit 74 using the same etching solution as the etching solution used in the step (5). In the same manner as in the step (8), an insulating layer 72 having a via hole opening 76 and having a roughened surface (not shown) formed on the surface thereof was laminated (see FIG. 19B).
Thereafter, a through hole 96 penetrating the substrate 71 and the insulating layer 72 was formed using a drill having a diameter of 350 μm, and further, a desmear process was performed on the wall surface of the through hole 96 (see FIG. 19C).

(15) Next, a catalyst is applied to the wall surface of the through hole 96 and the surface of the insulating layer 72 (including the inner wall surface of the via hole opening 76) in the same manner as used in the step (9). Furthermore, the substrate is immersed in an electroless copper plating aqueous solution similar to the electroless plating solution used in the step (10) above, and the surface of the insulating layer 72 (including the inner wall surface of the via hole opening 76), A thin-film conductor layer (electroless copper plating film) 82 was formed on the wall surface of the through hole 96 (see FIG. 20A).

(16) Next, a plating resist 73 is provided by a method similar to the method used in the step (11), and further, the plating resist 73 is not formed by a method similar to the method used in the step (12). An electrolytic copper plating film 83 having a thickness of 20 μm was formed on the formation part (see FIG. 20B).

(17) Next, the plating resist 73 is peeled off and the thin film conductor layer under the plating resist 73 is removed by a method similar to the method used in the step (13), and the conductor circuit 74 (via hole 77) is removed. Formed).
Furthermore, oxidation / reduction treatment was performed by the same method as used in the step (2) above, and the surface of the conductor circuit 74 and the surface of the conductor layer 95 were roughened (not shown) (FIG. 20 ( c)).

(18) Next, after placing the resin on the hole filling mask of the printing machine and filling the resin in the optical path through hole 81 by screen printing, conditions of 120 ° C. for 1 hour and 150 ° C. for 1 hour Then, the resin protruding from the through hole 81 for the optical path is polished with # 3000 abrasive paper, and further polished with 0.05 μm alumina particles to flatten the surface. Thereby, the resin composition layer 97 was formed.
In this process, as the resin, 40% by weight of pulverized silica having a particle size distribution of 0.1 to 0.8 μm is added to epoxy resin (transmittance 91% / mm, CTE 82 ppm) to obtain a transmittance 82% / mm, CTE 42 ppm. The viscosity was adjusted to 200,000 cps.

(19) Next, the optical waveguide 50 was formed at the end of the optical path through-hole 96 in which the resin composition layer 97 was formed using the following method.
First, an acrylic resin (refractive index 1.52, transmittance 94% / mm, CTE 72 ppm) as the core forming resin, and an acrylic resin (refractive index 1.51, transmittance 93% / mm, as the clad forming resin, CTE (70 ppm) was prepared by adding 25% by weight of pulverized silica having a particle size distribution of 0.1 to 0.8 μm so that the transmittance was 81% / mm, CTE was 53 ppm, and the viscosity was 1000 cps.

Next, a clad forming resin is applied to the end portion of the optical path through-hole using a spin coater (1000 pm / 10 sec), pre-baked at 80 ° C. for 10 minutes, 2000 mJ exposure treatment, and post-baked at 150 ° C. for 1 hour. The lower clad having a thickness of 50 μm was formed.
Next, a core forming resin is applied on the lower clad 52 using a spin coater (1200 pm / 10 sec), prebaked at 80 ° C. for 10 minutes, exposure treatment of 1000 mJ, and dipping using 1% TMH for 2 minutes. Development and post-baking at 150 ° C. for 1 hour were performed to form a core 51 having a width of 50 μm and a thickness of 50 μm.
Next, a clad forming resin is applied using a spin coater (1000 pm / 10 sec), pre-baked at 80 ° C. for 10 minutes, exposed to 2000 mJ, and post-baked at 150 ° C. for 1 hour to obtain a thickness on the core. Was formed into an optical waveguide 50 composed of a core 51 and a clad 52 (see FIG. 21A).
Thereafter, dicing processing using a 90 ° # 3000 blade was performed on both ends of the optical waveguide 50 to form 90 ° optical path conversion mirrors (see FIG. 21B). The transmission loss in the optical path conversion mirror formed in this way was 1.2 dB.

(20) Next, a solder resist composition (RPZ-1 manufactured by Hitachi Chemical Co., Ltd.) is applied to both sides of the substrate so that the thickness after curing is 30 μm, and is 70 ° C. for 20 minutes and 70 ° C. for 30 minutes. A drying process was performed under the conditions described above to form a layer 84 'of the solder resist composition (see FIG. 21 (c)).

(21) Next, a photomask having a thickness of 5 mm on which patterns of openings for forming solder bumps and openings for optical paths are drawn is brought into close contact with the layer 84 ′ of the solder resist composition opposite to the side where the optical waveguide 50 is formed. The film was exposed to 1000 mJ / cm ² of ultraviolet light and developed with a DMTG solution to form openings.
The optical path opening formed here is a circle having a diameter of 220 μm in plan view.
Accordingly, the solder resist layer formed in this step is formed so as to cover the interface between the optical path through hole and the resin composition.
Furthermore, the solder resist composition layer is cured by heat treatment at 80 ° C. for 1 hour, 100 ° C. for 1 hour, 120 ° C. for 1 hour, and 150 ° C. for 3 hours. A solder resist layer 84 having an optical path opening and a thickness of 30 μm was formed (see FIG. 22A).

(22) Next, the substrate on which the solder resist layer 84 is formed is made of nickel chloride (2.3 × 10 ⁻¹ mol / l), sodium hypophosphite (2.8 × 10 ⁻¹ mol / l), A nickel plating layer having a thickness of 5 μm is formed in the solder bump forming opening 98 by immersing in an electroless nickel plating solution containing sodium acid (1.6 × 10 ⁻¹ mol / l) at pH = 4.5 for 20 minutes. did. Furthermore, the substrate gold potassium cyanide ^{(7.6 × 10 -3 mol / l} ), ammonium chloride ^{(1.9 × 10 -1 mol / l} ), sodium citrate (1.2 × ¹⁰ -1 mol / l) Immerse in an electroless gold plating solution containing sodium hypophosphite (1.7 × 10 ⁻¹ mol / l) at 80 ° C. for 7.5 minutes to form a thickness of 0 on the nickel plating layer. A 0.03 μm gold plating layer was formed and used as a solder pad.

(23) Next, a fluorine polymer water-repellent coating agent (EGC-1700 manufactured by Sumitomo 3M Co.) is spray-coated on the entire surface of the solder resist layer on the side where the microlens is disposed, and air blow is performed. Surface treatment was applied by natural drying.
Further, the microlens 96 is attached to the end of the resin composition layer 97 opposite to the side on which the optical element is mounted using the ink jet device in the opening for the optical path formed in the solder resist layer 84 by the following method. Arranged.
That is, after preparing a UV curable epoxy resin (transmittance 94% / mm, refractive index 1.53) at room temperature (25 ° C.) and a viscosity of 20 cps, the resin is heated in a resin container of an ink jet apparatus. 40 ° C., the viscosity was adjusted to 8 cps, and then applied to a predetermined position at the end of the resin composition layer 97 so as to form a hemisphere having a diameter of 220 μm and a sag height of 10 μm, and further UV light (500 mW / The microlens 96 was disposed by curing the resin by irradiation.

(24) Next, solder paste was printed in the solder bump forming openings 98 formed in the solder resist layer 84 to form solder bumps 87, thereby obtaining a mother board (see FIG. 22B).

D. Manufacturing of Optical Communication Device After mounting an IC chip on the IC chip mounting substrate manufactured in Example 1, and further sealing the IC chip with a resin, this IC chip mounting substrate is manufactured in the above step C. Solder bumps were formed by connecting the solder bumps of both substrates by placing them oppositely at predetermined positions on the substrate and reflowing at 200 ° C.
Thereafter, an IC chip mounting substrate sealing layer was formed by using the following method so as to be in contact with the outer periphery of the IC chip mounting substrate, and an optical communication device was manufactured.
That is, 75 wt% spherical silica having a particle size distribution of 1 to 100 μm and an average particle size of 25 μm is added to an epoxy resin, and a resin composition having a CTE of 20 ppm, a viscosity of 250 Pa · s, and a thixo ratio of 1.7 is obtained by botting. After applying so as to be in contact with the outer periphery of the IC chip mounting substrate, a curing process was performed at 150 ° C. for 2 hours to form an IC chip mounting substrate sealing layer.

In the optical communication device manufactured in this example, the distance between the bottom surface of the IC chip mounting substrate and the scene of the motherboard substrate is 300 μm.
In the optical communication device of this embodiment, a gap is formed between the optical signal transmission optical path of the IC chip mounting substrate and the optical signal transmission optical path of the motherboard substrate.

(Example 5)
In Example 4, as the IC chip mounting substrate to be mounted on the motherboard, the IC chip was mounted on the IC chip mounting substrate manufactured in Example 3 and this IC chip was sealed with resin. Manufactured an optical communication device in the same manner as in Example 4.

(Example 6)
In Example 4, as the IC chip mounting substrate to be mounted on the motherboard, the IC chip mounted on the IC chip mounting substrate manufactured in Example 3 and the IC chip that was not resin-sealed was used. Except for the above, an optical communication device was manufactured in the same manner as in Example 4.

(Example 7)
In the process D of Example 4, before forming the IC chip mounting substrate sealing layer, a predetermined position on the solder resist layer of the motherboard substrate (after the IC chip mounting substrate to be mounted later) is formed by the following method. A dam for stopping the flow of the uncured optical element sealing resin is formed at the bottom, and then a commercially available underfill resin (CCN800D, manufactured by Kyushu Matsushita Electric Co., Ltd.) is applied around the optical element with a dispenser. Further, an optical communication device was manufactured in the same manner as in Example 4 except that the IC chip mounting substrate sealing layer was formed by performing a curing process.
The dam was formed by silk-printing an epoxy resin and then performing a curing process.

(Example 8)
Example 4 is the same as Example 4 except that the step of forming the IC chip mounting substrate sealing layer of Example 4 is not performed and a cap member that covers the IC chip mounting substrate is attached using the following method. Thus, an IC chip mounting substrate was manufactured.
First, the entire surface of one side of the double-sided copper-clad glass epoxy substrate is etched, and then the electrolytic Ni / Au layer (Ni 5 μm, Au 0.5 μm is applied to the copper side. A member was prepared.
Next, a resin composition in which spherical silica having a particle size distribution of 1 to 30 μm and an average particle size of 4 μm is added to an epoxy resin at a position where a cap member is attached (viscosity 200 Pa · s, thixo ratio 1.8, CTE 30 ppm) Was applied with a dispenser and cured to the B stage in an oven.
Thereafter, the cap member was temporarily fixed while being aligned on the substrate, a 2 g / mm ² weight was placed on the cap member, and the resin composition was cured in an oven to attach the cap member. Note that flux cleaning was performed after mounting the IC chip mounting substrate.

Example 9
In Example 8, as the IC chip mounting substrate to be mounted on the motherboard, the IC chip was mounted on the IC chip mounting substrate manufactured in Example 3, and this IC chip was resin-encapsulated. In the same manner as in Example 7, an optical communication device was manufactured.

(Example 10)
In Example 8, as the IC chip mounting substrate to be mounted on the motherboard, the IC chip mounted on the IC chip mounting substrate manufactured in Comparative Example 1 and the IC chip not sealed with resin was used. Except for the above, an optical communication device was manufactured in the same manner as in Example 8.

(Comparative Example 2)
In Example 4, an optical communication device was manufactured in the same manner as in Example 4 except that the IC chip mounting substrate sealing layer was not formed.

About the optical communication device which concerns on Examples 4-10, the optical signal transmission capability was evaluated with the following method.
That is, the light emitting element of the IC chip mounting substrate emits light, the optical signal transmission optical path of the IC chip mounting substrate, the optical signal transmission optical path of the motherboard, the optical waveguide, the optical signal transmission optical path of the motherboard, and the IC chip When the optical signal transmitted through the optical path for optical signal transmission on the mounting board is received by the light receiving element of the IC chip mounting board and the eye pattern of the electrical signal via the receiver IC is confirmed, transmission of 1.25 Gbps is performed. It was possible to confirm the optical communication devices according to the examples and the comparative examples.
It was also confirmed that an optical signal can be transmitted in the same manner for 2.5 Gbps transmission.

Next, the optical communication devices according to the example and the comparative example were left in an environment where dust is relatively generated, and then transported in a box. Then, the optical signal transmission capability of the device for optical communication was evaluated using the method described above. As a result, the optical communication device according to the example was able to transmit an optical signal as before being left in an environment where dust was generated.
On the other hand, some optical communication devices according to the comparative example cannot transmit an optical signal. This is presumably because dust has entered the optical path for optical signal transmission.

Moreover, about the optical communication device of Examples 4-10, the liquid phase temperature cycle test similar to the liquid phase temperature cycle test performed in Test Examples 1-5 is performed, About the sealing property of the board | substrate for IC chip mounting after that A growth leak test was conducted in accordance with MIL-STD-833. That is, the sealing property was evaluated by observing the generation of bubbles after immersing the optical communication device in a fluorocarbon liquid for 1 minute.
As a result, it was revealed that the optical communication devices of Examples 4 to 10 have sufficient sealing properties.

In addition, for optical communication devices of Examples 4 to 10, a dummy IC chip obtained by performing aluminum sputtering on the entire surface of the IC chip mounting substrate was previously wire-bonded, and the resistance change rate after the liquid phase temperature cycle test was determined. When measured, the resistance change rate was less than 5% for all the optical communication devices.

Further, in Example 5, when a cap member made of ceramic is used instead of a cap member made of resin material, and a cap member made of ceramic is used instead of a cap member made of a resin material, and an IC chip is made of resin. The result similar to Example 5 was obtained also about the case where it sealed.
Further, in Example 5, a cap member made of ceramic is used instead of a cap member made of a resin material, and the same result as in Example 5 is obtained when the cap member is attached via solder instead of an adhesive. was gotten. Here, in order to attach the cap member via solder, a pad was previously formed on the outermost insulating layer, and no solder resist layer was formed on this portion.

Further, in Example 10, when a cap member made of ceramic was used instead of the cap member made of a resin material, the same result as in Example 10 was obtained.
Moreover, while using the cap member which consists of ceramics in Example 10, when replacing a cap member with the adhesive agent and attaching via solder, the result similar to Example 10 was obtained. Here, in order to attach the cap member via solder, a pad was previously formed on the outermost insulating layer, and no solder resist layer was formed on this portion.

Moreover, in Examples 8-10, although flux cleaning was performed, when flux cleaning was not performed, the transmission loss of the optical signal might increase. This is considered to be the influence of the remaining flux component.

In the optical communication devices according to Examples 4 to 10, a 1-channel light-emitting element and a light-receiving element are mounted as optical elements, respectively. Instead of these optical elements, a 4-channel light-emitting element and light-receiving element are used. Similar results were obtained with an optical communication device that was mounted and the cross-sectional size of the optical path for optical signal transmission was increased accordingly.

In the optical communication device according to the third aspect of the present invention, since a gap portion may exist between the IC chip mounting substrate and the solder resist layer of the motherboard substrate, the air present in the gap portion is thermally expanded. As a result, there is a concern that cracks may occur in the solder connection portions of the both, the IC chip mounting substrate sealing layer, and the like. Therefore, the following test examples 6 to 10 are performed, and the influence due to the difference in the portion where the IC chip mounting substrate sealing layer is formed is affected by the solder connection portion and the IC chip mounting substrate sealing layer after the liquid phase temperature cycle test, Evaluation was made using the presence or absence of cracks on an IC chip mounting substrate, a motherboard substrate, or the like as an index.

(Test Example 6)
Basically, an optical communication device was manufactured by the same method as in Example 4. However, when forming the IC chip mounting substrate sealing layer, the IC chip mounting substrate sealing layer was formed so that the sealing resin layer was present only outside the solder bumps.

(Test Example 7)
Basically, an optical communication device was manufactured by the same method as in Example 4. However, when the IC chip mounting substrate sealing layer is formed, the sealing resin layer also exists inside the solder bumps, and the IC chip mounting substrate sealing is performed so that the solder bumps are buried in the sealing resin layer. A stop layer was formed.

(Test Example 8)
Basically, an optical communication device was manufactured by the same method as in Example 4. However, when the IC chip mounting substrate sealing layer is formed, the sealing resin layer is also present inside the solder bump, and the solder bump is embedded in the sealing resin layer and the solder bump. The substrate sealing layer for mounting an IC chip was formed so that a portion where the sealing resin layer was formed only on the outside was mixed.

(Test Example 9)
An IC chip mounting substrate was manufactured in the same manner as in Comparative Example 2. That is, the IC chip mounting substrate sealing layer was not formed.

(Test Example 5)
Basically, an optical communication device was manufactured by the same method as in Example 4. However, in place of the IC chip mounting substrate sealing layer, an underfill was formed between the IC chip mounting substrate and the motherboard substrate.

With respect to the IC chip mounting substrates according to these test examples 6 to 10, liquid phase temperature cycle tests similar to those of test examples 1 to 5 were performed, and for each of the five optical communication devices, 0 cycle, 250 cycles, 500 cycles and After 1000 cycles, the optical communication device is cross-cut, and cracks occur in the IC chip mounting substrate sealing layer cross section, the solder connection section cross section, the IC chip mounting substrate cross section, and the motherboard substrate cross section. It was observed with a microscope.
As a result, no crack was observed in any of the optical communication devices.

Therefore, in the optical communication device of the third aspect of the present invention, an optical chip is transmitted between the IC chip mounting substrate and the motherboard substrate by forming the IC chip mounting substrate sealing layer. It has been clarified that even if a void portion is formed in the portion), the optical communication device is not adversely affected.

(A) is sectional drawing which shows typically an example of the board | substrate for IC chip mounting of 1st this invention, (b), (c) is another of the board | substrate for IC chip mounting of 1st this invention. It is a fragmentary sectional view showing a part of one example typically. It is sectional drawing which shows typically an example of the board | substrate for IC chip mounting of 1st this invention. It is sectional drawing which shows typically an example of the board | substrate for IC chip mounting of 1st this invention. It is sectional drawing which shows typically an example of the board | substrate for IC chip mounting of 2nd this invention. It is sectional drawing which shows typically an example of the board | substrate for motherboards of 2nd this invention. It is sectional drawing which shows typically an example of the board | substrate for IC chip mounting mounted in the device for optical communication of this invention. It is sectional drawing which shows typically an example of embodiment of the device for optical communication of 3rd this invention. It is sectional drawing which shows typically another example of embodiment of the device for optical communication of 3rd this invention. It is sectional drawing which shows typically an example of embodiment of the device for optical communication of 4th this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for IC chip mounting of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for IC chip mounting of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for IC chip mounting of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for IC chip mounting of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for IC chip mounting of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for IC chip mounting of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for IC chip mounting of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for motherboards which comprises the device for optical communication of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for motherboards which comprises the device for optical communication of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for motherboards which comprises the device for optical communication of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for motherboards which comprises the device for optical communication of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for motherboards which comprises the device for optical communication of this invention. It is sectional drawing which shows typically a part of manufacturing method of the board | substrate for motherboards which comprises the device for optical communication of this invention.

Explanation of symbols

120, 220, 320, 420, 520 IC chip mounting substrate 121, 221, 321, 421, 521 Substrate 122, 222, 322, 422, 522 Insulating layer 124, 224, 324, 424, 524 Conductor circuits 127, 227, 327, 427, 527 Via hole 129, 229, 329, 429, 529 Through hole 134, 234, 334, 434, 534 Solder resist layer 138, 238, 338, 438, 538 Light emitting element 139, 239, 339, 439, 539 Light receiving elements 142, 242, 342, 442, 542 Optical signal transmission optical paths 146, 246, 346, 446, 546 Microlenses 148, 248, 348 Optical element sealing layers 418, 518 Cap members 419, 519 Adhesives 720, 820 920 Motherboard Substrate 721, 821, 921 Substrate 722, 822, 921 Insulating layer 724, 824, 924 Conductor circuit 727, 827, 927 Via hole 729, 829 929 Through hole 734, 834, 934 Solder resist layer 742, 842, 942 Light Optical path for signal transmission 746, 846, 946 Microlens 740, 850, 950 Optical waveguide 760, 860, 960 Optical communication devices 1720, 1820, 2720, 2820 IC chip mounting substrate

Claims (11)

An IC chip mounting substrate in which a conductor circuit and an insulating layer are laminated on both surfaces of the substrate, an optical element is mounted, and an optical path for transmitting an optical signal is formed.
An IC chip mounting substrate, wherein an optical element sealing layer is formed in contact with an outer periphery of the optical element. 2. The IC chip mounting substrate according to claim 1, wherein a gap is formed in a portion of the optical signal transmission optical path that is in contact with the optical element. The IC chip mounting substrate according to claim 1, wherein the optical element sealing layer is made of a resin. An IC chip mounting substrate in which a conductor circuit and an insulating layer are laminated on both surfaces of the substrate, an optical element is mounted, and an optical path for transmitting an optical signal is formed.
An IC chip mounting substrate, wherein a cap member is attached so as to cover at least the optical element. The IC chip mounting substrate according to claim 4, wherein the cap member is bonded and fixed with resin or solder. 6. The IC chip mounting substrate according to claim 1, wherein the optical element is a light receiving element and / or a light emitting element. An IC chip mounting substrate in which an optical element is mounted on a motherboard for a substrate in which a conductor circuit and an insulating layer are laminated and formed on at least one surface of the substrate, an optical waveguide is formed, and an optical path for optical signal transmission is further formed Is a device for optical communication,
An optical communication device, wherein an IC chip mounting substrate sealing layer is formed so as to be in contact with the outer periphery of the IC chip mounting substrate. The optical communication device according to claim 7, wherein a gap is formed in a portion of the optical signal transmission optical path in contact with the IC chip mounting substrate. 9. The IC chip mounting substrate according to claim 7, wherein the IC chip mounting substrate sealing layer is made of a resin. An IC chip mounting substrate in which an optical element is mounted on a motherboard for a substrate in which a conductor circuit and an insulating layer are laminated and formed on at least one surface of the substrate, an optical waveguide is formed, and an optical path for optical signal transmission is further formed Is a device for optical communication,
An optical communication device, wherein a cap member is attached so as to cover at least the IC chip mounting substrate. The optical communication device according to claim 10, wherein the cap member is bonded and fixed with resin or solder.

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