JP4014464B2 - Optical communication device and method for manufacturing optical communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical communication device and a method for manufacturing an optical communication device.
[0002]
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. In communication systems using fiber, the number of repeaters can be greatly reduced compared to communication systems using conventional metallic cables, making construction and maintenance easier, making the communication system more economical and more reliable. Can be achieved.
[0003]
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.
[0004]
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.
[0005]
As described above, when optical communication is used for communication between the backbone network and the terminal device, an IC that performs information (signal) processing in the terminal device operates with an electrical signal. Therefore, the terminal device includes an optical-to-electric converter, It is necessary to attach a device (hereinafter also referred to as an optical / electrical converter) that converts an optical signal and an electrical signal, such as an electrical-to-optical converter. Therefore, in a conventional terminal device, for example, a package substrate on which an IC chip is mounted, an optical component such as a light receiving element or a light emitting element that processes an optical signal, and the like are separately mounted, and an electrical wiring or an optical waveguide is connected to them, Signal transmission and signal processing were performed.
[0006]
[Problems to be solved by the invention]
In such a conventional terminal device, since the IC mounting package substrate and the optical component are separately mounted, the entire apparatus becomes large, which is a factor that hinders the miniaturization of the terminal device.
Further, in the conventional terminal device, since the distance between the IC mounting package substrate and the optical component is large, the electric wiring distance is long, and a signal error due to crosstalk noise or the like is likely to occur during signal transmission.
[0007]
[Means for Solving the Problems]
Therefore, as a result of intensive studies, the present inventors can achieve optical communication with excellent connection reliability by arranging an IC chip mounting substrate on which various optical components are mounted and a multilayer printed wiring board to face each other. The present inventors have found that it is possible to contribute to miniaturization of terminal equipment, and have completed the optical communication device of the present invention having the following configuration.
Furthermore, in an optical communication device, when a sealing resin layer is formed between an IC chip mounting substrate and a multilayer printed wiring board that are arranged to face each other, foreign matters floating in the air between optical components, etc. In addition, the stress generated between the IC chip mounting substrate and the multilayer printed wiring board can be relieved, so that it has been found that the optical communication device is more reliable.
[0008]
That is, the optical communication device of the present invention has an optical signal transmission optical path formed, and an IC chip mounting substrate having an optical element mounted on one surface;
An optical communication device comprising at least a multilayer printed wiring board on which an optical waveguide is formed,
The optical signal transmission optical path is formed so as to penetrate the IC chip mounting substrate, and an optical path resin layer is formed therein,
A microlens is disposed at least on the end of the optical signal transmission optical path on the multilayer printed wiring board side,
A sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board,
The refractive index of the microlens is larger than the refractive index of the sealing resin layer,
The optical waveguide and the optical element are configured to transmit an optical signal through the optical signal transmission optical path.
Further, in the optical communication device, the multilayer printed wiring board has an optical path opening in which an optical path resin layer is formed,
It is desirable that a micro lens having a refractive index larger than that of the sealing resin layer is disposed at an end of the optical path opening on the sealing resin layer side.
In the optical communication device, the thickness of the optical signal transmission optical path and the thickness of the optical path opening are the same, and
It is desirable that the refractive index of the microlens disposed at the end portion of the optical signal transmission optical path is the same as the refractive index of the microlens disposed at the end portion of the optical path opening.
[0009]
Of the present inventionIn the optical communication device, it is desirable that the sealing resin layer has a communication wavelength light transmittance of 70% or more.
Furthermore, it is desirable that the sealing resin layer contains particles.
[0011]
In the optical communication device, the optical element is preferably a light receiving element and / or a light emitting element.
[0012]
An optical communication device manufacturing method according to the present invention includes: an optical chip for optical signal transmission; an IC chip mounting substrate on which an optical element is mounted on one surface; and a multilayer printed wiring including at least an optical waveguide After manufacturing the board separately,
Between the optical element of the IC chip mounting substrate and the optical waveguide of the multilayer printed wiring board, both are arranged and fixed at a position where an optical signal can be transmitted,
Further, a sealing resin layer is formed by pouring a sealing resin composition between the IC chip mounting substrate and the multilayer printed wiring board, followed by curing treatment.A method of manufacturing a device for optical communication,
When forming the optical path for optical signal transmission, the optical chip is formed so as to penetrate the IC chip mounting substrate, and an optical path resin layer is formed therein, and the multilayer print of the optical path for optical signal transmission is further formed. A microlens having a refractive index larger than that of the sealing resin layer is disposed at an end portion facing the wiring board.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the optical communication device of the present invention will be described.
An optical communication device according to the present invention has an optical signal transmission optical path formed thereon, an IC chip mounting substrate having an optical element mounted on one surface, and
An optical communication device comprising at least a multilayer printed wiring board on which an optical waveguide is formed,
The optical signal transmission optical path is formed so as to penetrate the IC chip mounting substrate, and an optical path resin layer is formed therein,
A microlens is disposed at least on the end of the optical signal transmission optical path on the multilayer printed wiring board side,
A sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board,
The refractive index of the microlens is larger than the refractive index of the sealing resin layer,
The optical waveguide and the optical element are configured to transmit an optical signal through the optical signal transmission optical path.
[0014]
The optical communication device of the present invention is composed of an IC chip mounting substrate on which an optical element is mounted at a predetermined position and a multilayer printed wiring board on which an optical waveguide is formed at a predetermined position. Connection loss between optical components is low, and connection reliability is excellent as an optical communication device.
In the optical communication device, the optical component and the electronic component necessary for optical communication can be integrated, which can contribute to miniaturization of the optical communication terminal device.
[0015]
In the optical communication device of the present invention, it is desirable that a sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board. In the case where a sealing resin layer is formed, dust or foreign matter floating in the air does not enter between the optical element and the optical waveguide, and optical signals are transmitted by the dust or foreign matter. Therefore, the reliability as an optical communication device is more excellent.
[0016]
Further, when a sealing resin layer is formed, the sealing resin layer generates stress caused by a difference in thermal expansion coefficient between the IC chip mounting substrate and the multilayer printed wiring board. Since it can play the role of mitigating, for example, breakage in the vicinity of solder bumps connecting the IC chip mounting substrate and the multilayer printed wiring board can be prevented. Further, when the sealing resin layer is formed, the positional deviation of the optical element or the optical waveguide is less likely to occur, and the transmission of the optical signal between the optical element and the optical waveguide is not hindered.
Therefore, also from such a point, when the sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board, the reliability as an optical communication device is more excellent.
[0017]
In the optical communication device of the present invention, it is preferable that the IC chip mounting substrate and the multilayer printed wiring board are electrically connected via solder bumps. This is because both can be more reliably arranged at a predetermined position by the self-alignment action of the solder.
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 the reflow process. It is thought that this occurs due to the strong surface tension that tends to become spherical when the solder is attached to the metal. When this self-alignment action is used, when connecting the IC chip mounting substrate on the multilayer printed wiring board via the solder bumps, it is assumed that a positional deviation has occurred between the two before reflowing. In addition, the IC chip mounting substrate moves during reflow, and the IC chip mounting substrate can be attached to an accurate position on the multilayer printed wiring board.
Therefore, if the optical components such as the light receiving element, the light emitting element, and the optical waveguide are attached to the IC chip mounting substrate and the multilayer printed wiring board at accurate positions, the multilayer printed wiring is provided via the solder bumps. By connecting the IC chip mounting substrate on the plate, an optical communication device having excellent connection reliability can be manufactured.
[0018]
Hereinafter, an optical communication device of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing an embodiment of an optical communication device of the present invention. FIG. 1 shows an optical communication device in a state where an IC chip is mounted.
[0019]
As shown in FIG. 1, the optical communication device 150 includes an IC chip mounting substrate 120 on which an IC chip 140 is mounted and a multilayer printed wiring board 100. The IC chip mounting substrate 120, the multilayer printed wiring board 100, and the like. Are electrically connected via a solder connection portion 137.
A sealing resin layer 160 is formed between the IC chip mounting substrate 120 and the multilayer printed wiring board 100.
[0020]
The IC chip mounting substrate 120 is formed by laminating conductor circuits 124 and 125 and an interlayer resin insulation layer 122 on both surfaces of the substrate 121, and conductor circuits sandwiching the substrate 121 and conductors sandwiching the interlayer resin insulation layer 122. The circuits are electrically connected to each other through a through hole 129 and a via hole 127. A solder resist layer 134 is formed on the outermost layer.
In this IC chip mounting substrate 120, optical signal transmission optical paths 141 (141a, 141b) are formed which penetrate the substrate 121 having the conductor circuits 124, 125, the interlayer resin insulation layer 122, and the solder resist layer 134 formed on both sides. In the optical signal transmission optical path 141, a conductor layer 145 is formed on the wall surface, and an optical path resin layer 142 is formed therein.
In addition, the said conductor layer does not need to be formed.
[0021]
Further, on one surface of the IC chip mounting substrate 120, the light receiving element 138 and the light emitting element 139 have the solder connection part 144 so that the light receiving part 138a and the light emitting part 139a face the optical path 141 for optical signal transmission. The IC chip 140 is surface-mounted via the solder connection portion 143.
[0022]
In the multilayer printed wiring board 100, the conductor circuit 104 and the interlayer resin insulating layer 102 are laminated on both surfaces of the substrate 101, and the conductor circuits sandwiching the substrate 101 and the conductor circuits sandwiching the interlayer resin insulating layer 102 are These are electrically connected through a through hole 109 and a via hole 107, respectively.
In addition, a solder resist layer 114 having an optical path opening 111 and solder bumps is formed on the outermost layer of the multilayer printed wiring board 100 facing the IC chip mounting substrate 120, and an optical path opening 111 ( 111a and 111b) are formed optical waveguides 118 (118a and 118b) including optical path conversion mirrors 119 (119a and 119b), and an optical path resin layer 108 is formed in the optical path opening 111. .
[0023]
In the optical communication device 150 having such a configuration, an optical signal transmitted from the outside via an optical fiber or the like (not shown) is introduced into the optical waveguide 118a, and the optical path conversion mirror 119a and the optical path opening 111a are introduced. Furthermore, after being sent to the light receiving element 138 (light receiving part 138a) via the sealing resin layer 160 and the optical path for optical signal transmission 141a, the light receiving element 138 converts it into an electrical signal, and further, a conductor circuit and a solder connection It is sent to the IC chip 140 via the unit.
[0024]
The electrical signal sent out from the IC chip 140 is sent to the light emitting element 139 through the solder connection portion and the conductor circuit, and then converted into an optical signal by the light emitting element 139. This optical signal is converted into the light emitting element 139 (light emitting element 139). 139a) is introduced into the optical waveguide 118b through the optical signal transmission optical path 141b, the sealing resin layer 160, the optical path opening 111b, and the optical path conversion mirror 119b, and further through the optical fiber or the like (not shown). Will be sent to the outside.
[0025]
In such an optical communication device of the present invention, since the optical / electrical signal conversion is performed in the IC chip mounting substrate, that is, at a position close to the IC chip, the transmission distance of the electric signal is short, and higher speed communication is supported. In addition, since the optical component and the electronic component necessary for optical communication can be integrated, it is possible to contribute to the miniaturization of the terminal device for optical communication.
[0026]
In the optical communication device, the electrical signal sent out from the IC chip is converted into an optical signal as described above, and then sent out to the outside through the optical fiber. Sent to the multilayer printed wiring board, and sent to other IC components such as IC chips mounted on the multilayer printed wiring board via the conductor circuit (including via holes and through holes) of the multilayer printed wiring board. It becomes.
[0027]
In the optical communication device 150 shown in FIG. 1, a sealing resin layer 160 is formed between the IC chip mounting substrate 120 and the multilayer printed wiring board 100. As described above, the optical communication device in which the sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board floats in the air between the optical element and the optical waveguide. Therefore, it is more reliable because the transmission of optical signals is not hindered by the presence of dust or foreign matter.
[0028]
The sealing resin layer is not particularly limited as long as it has little absorption in the communication wavelength band, and examples of the material include a thermosetting resin, a thermoplastic resin, a photosensitive resin, and a thermosetting resin. Examples thereof include a resin partially sensitized and an ultraviolet curable resin. Among these, a thermosetting resin is desirable.
Specifically, for example, acrylic resins such as PMMA (polymethyl methacrylate), deuterated PMMA, deuterated fluorinated PMMA; polyimide resins such as fluorinated polyimide; epoxy resins; UV curable epoxy resins; Examples thereof include silicone resins such as resins; polymers produced from benzocyclobutene.
[0029]
Moreover, it is desirable that the sealing resin layer 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 and the reliability of the device for optical communication may be lowered. The transmittance is more preferably 90% or more.
In particular, when the sealing resin layer is composed of only the resin component described above, the transmittance is desirably 90% or more, and as described later, when particles are blended in the sealing resin layer Therefore, the transmittance is desirably 70% or more.
[0030]
In the present specification, the transmittance of communication wavelength light refers to the transmittance of communication wavelength light per 1 mm length. Specifically, strength I₁When the light enters the sealing resin layer and passes through the sealing resin layer by 1 mm, the intensity of the emitted light is I₂Is a value calculated by the following equation (1).
[0031]
Transmittance (%) = (I₂/ I₁) × 100 (1)
[0032]
In addition, the said transmittance | permeability means the transmittance | permeability measured at 25-30 degreeC.
[0033]
The sealing resin layer preferably contains particles such as resin particles, inorganic particles, and metal particles.
By including particles, the thermal expansion coefficient can be matched between the IC chip mounting substrate and the multilayer printed wiring board, and cracks and the like due to the difference in thermal expansion coefficient are less likely to occur. It is.
[0034]
In the optical communication device of the present invention comprising the IC chip mounting substrate and the multilayer printed wiring board, the thermal expansion coefficient (z-axis direction) of the constituent members is, for example, 5.0 × 10 for the substrate.^-Five~ 6.0 × 10^-Five(/ ° C.), interlayer resin insulation layer is 6.0 × 10^-Five~ 8.0 × 10^-Five(/ ° C) grade, particles 0.1 × 10^-Five~ 1.0 × 10^-Five(/ ° C.), sealing resin layer is 0.1 × 10^-Five~ 100 × 10^-Five(/ ° C) degree, sealing resin layer in which particles are blended is 3.0 × 10^-Five~ 4.0 × 10^-FiveAn optical element made of IC chip, silicon, germanium or the like is 0.5 × 10^-Five~ 1.5 × 10^-Five(/ ° C) grade, conductor circuit is 1.0 × 10^-Five~ 2.0 × 10^-Five(/ ° C). In addition, the measurement temperature of the said thermal expansion coefficient is 20 degreeC.
Thus, when the particles are blended in the sealing resin layer, the difference in coefficient of thermal expansion between the sealing resin layer and other constituent members constituting the optical communication device is reduced. Therefore, stress will be relieved.
Further, when particles are blended in the sealing resin layer, positional deviation of the optical element or the optical waveguide is less likely to occur.
[0035]
Moreover, when mix | blending particle | grains with the said sealing resin layer, it is desirable that the refractive index of the resin component of this sealing resin layer and the refractive index of the said particle | grain are comparable. Therefore, when blending particles in the encapsulating resin layer, it is desirable to mix 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, silica particles having a refractive index of 1.54 and titania particles having a refractive index of 1.52 are mixed and used. Is desirable.
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.
[0036]
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 thereof include those composed of a composite of a photosensitive resin and a thermoplastic resin.
[0037]
Specifically, for example, 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 resins) (Epoxy group) in which methacrylic acid or acrylic acid is reacted to give an acrylic group; phenoxy resin, polyether sulfone (PES), polysulfone (PSF), polyphenylene sulfone (PPS), polyphenylene sulfide (PPES), Examples thereof include thermoplastic resins such as polyphenyl ether (PPE) and polyetherimide (PI); and 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.
[0038]
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. 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.
[0039]
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.
[0040]
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 spherical or oval spherical particles do not have corners, so that cracks and the like are less likely to occur in the sealing resin layer.
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.
[0041]
The desirable lower limit of the particle size of the particles is 0.01 μm, and the more desirable lower limit is 0.1 μm. On the other hand, the desirable upper limit of the particle size is 100 μm, and the more desirable upper limit is 50 μm. In particular, the upper limit is desirably shorter than the communication wavelength. This is because if the average particle size of the particles is shorter than the communication wavelength, there is less possibility that the transmission of the optical signal will be hindered.
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 included.
In the present specification, the particle diameter of the particle means the length of the longest part of the particle.
[0042]
A desirable lower limit of the amount of the particles contained in the sealing resin layer is 10% by weight, and a more desirable lower limit is 20% by weight. On the other hand, the desirable upper limit of the compounding amount 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.
In addition, since the composition of the sealing resin layer affects the reliability of optical signal transmission loss, heat resistance, bending strength, etc., the specific composition is such that the sealing resin layer has a low optical signal loss characteristic. It may be appropriately selected so as to satisfy excellent heat resistance and crack resistance.
[0043]
In the optical communication device of the present invention, it is desirable that the refractive index of the optical signal transmission optical path and the refractive index of the sealing resin layer are the same. For example, when the refractive index of the optical signal transmission optical path is smaller than the refractive index of the sealing resin layer, the optical signal transmitted through the optical signal transmission optical path is directed toward the light receiving portion of the light receiving element. The optical signal sent out from the light-emitting element will be refracted in a direction not spreading at the interface between the optical signal transmission optical path and the sealing resin layer, but the refractive index of the two is different. As a result, the reflection of the optical signal occurs at the interface between the optical path for transmitting the optical signal and the sealing resin layer, and as a result, the transmission loss of the optical signal increases. Therefore, in order to reduce the transmission loss of the optical signal, it is desirable that the refractive index of the optical path for optical signal transmission and the refractive index of the sealing resin layer are the same. In consideration of the degree of reflection of the optical signal at the interface with the resin layer and the degree of refraction, the refractive indexes of both are appropriately selected.
[0044]
The refractive index of the resin component used for the sealing resin layer is, for example, about 1.50 to 1.60 for epoxy resin, about 1.40 to 1.55 for acrylic resin, and 1.55 to polyolefin. As a method for adjusting the refractive index of the sealing resin layer and the like, for example, the polarizability may be changed by fluorinating or phenylating a part of the resin component, And a method of changing the refractive index of the resin component by changing the molecular weight by deuterating a part of the resin component. Such a method for adjusting the refractive index can also be used as a method for adjusting the refractive index of the optical waveguide.
[0045]
In the optical communication device, the optical path for optical signal transmission desirably has an optical path resin layer formed therein as shown in FIG. As described above, in the optical communication device of the present invention, it is desirable that a sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board. When the sealing resin layer is formed, when the sealing resin layer is formed, the sealing resin layer may enter a part of the optical signal transmission optical path, thereby transmitting the optical signal. This is because it may be disturbed.
[0046]
In the optical communication device, it is desirable that a conductor layer is formed on the wall surface of the optical path for transmitting optical signals, as shown in FIG. This is because by forming a conductor layer on the wall surface of the optical path for optical signal transmission, it is possible to reduce irregular reflection of light on the wall surface of the optical path for optical signal transmission and improve the transmission performance of the optical signal.
[0047]
Further, in the optical communication device, it is desirable that an optical path resin layer is also formed in the optical path opening provided in the multilayer printed wiring board. In this case, the refractive index and sealing of the optical path resin layer are preferable. It is desirable that the refractive index of the resin layer be the same. This is because when the refractive indexes of both are the same, the transmission loss of the optical signal can be reduced as in the case where the refractive index of the optical path for transmitting the optical signal and the refractive index of the sealing resin layer are the same. .
Further, when the inside of the optical path opening is a void, in the step of forming the sealing resin layer at the time of manufacturing the optical communication device, the uncured resin composition for forming the sealing resin layer is the above In some cases, a void may occur in the gap of the optical path opening, and the generation of such a void may adversely affect the optical signal transmission capability of the optical communication device. Such a problem does not occur when the optical path resin layer is formed.
[0048]
In addition, a sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board, and an optical path resin layer is formed inside the optical signal transmission optical path. When the optical path resin layer is also formed inside the opening, the refractive indexes of the sealing resin layer, the optical signal transmission optical path, and the optical path resin layer in the optical path opening are the same. It is desirable that This is because when the three refractive indexes are the same, no optical signal is reflected at the interface between the sealing resin layer and the optical path resin layer.
[0049]
In the optical communication device, it is preferable that a microlens is disposed on at least one end of the optical signal transmission optical path.
FIG. 2 is a cross-sectional view schematically showing another embodiment of the device for optical communication of the present invention.
The optical communication device 250 shown in FIG. 2 includes the IC chip mounting substrate 220 and the multilayer printed wiring board 200, as in the optical communication device 150 shown in FIG. A sealing resin layer 260 is formed between the wiring board 200 and the wiring board 200.
Further, in the IC chip mounting substrate 220, the microlens 246 is disposed at the end of the optical signal transmission optical path 241 in which the optical path resin layer 242 is formed on the multilayer printed wiring board 200 side.
Thus, by arranging the microlens, an optical signal can be transmitted more reliably between the optical element (light receiving element and light emitting element) and the optical waveguide.
[0050]
The embodiment of the optical communication device 250 is the same as the embodiment of the optical communication device 150 except that the microlens 246 is disposed at one end of the optical signal transmission optical path 242 of the IC chip mounting substrate 220. It is.
[0051]
In addition, it is desirable that the refractive index of the microlens disposed at one end (on the multilayer printed wiring board side) of the optical signal transmission optical path is larger than the refractive index of the sealing resin layer. By arranging the microlens having such a refractive index, the optical signal can be condensed in a desired direction, so that the optical signal can be transmitted more reliably.
[0052]
In addition, when the microlens is a convex lens having a convex surface only on one side (encapsulation resin layer side) as shown in FIG. 2, the radius of curvature of the microlens takes into account the focal length of the microlens. Select as appropriate. Specifically, the radius of curvature is reduced when the focal length of the microlens is increased, and the radius of curvature is increased when the focal length is shortened.
[0053]
Further, when the microlens is disposed and the optical path resin layer is formed inside the optical signal transmission optical path, the refractive index of the microlens is larger than the refractive index of the optical path resin layer. It may be the same as the refractive index of the optical path resin layer.
[0054]
Although not shown, when the optical path resin layer is also formed inside the optical path opening of the multilayer printed wiring board, the micro path is also formed at the end of the optical path opening on the sealing resin layer side. It is desirable that a lens is provided. In this case, the refractive index of the microlens is preferably larger than the refractive index of the sealing resin layer.
[0055]
Also, a microlens is disposed at the end of the optical path opening, and the optical path opening has an optical path resin layer formed therein, and an optical signal transmission having an optical path resin layer formed therein. When the thickness of the optical path is substantially the same, the refractive index of the microlens disposed at the end of the optical path opening and the refractive index of the microlens disposed at the end of the optical signal transmission optical path Is preferably substantially the same.
By disposing the microlens having such a refractive index, the optical signal transmission optical path can be condensed in a desired direction, so that the optical signal can be transmitted more reliably.
[0056]
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 optical lens resin include acrylic resins such as PMMA (polymethyl methacrylate), deuterated PMMA, and deuterated fluorinated PMMA; polyimide resins such as fluorinated polyimide; epoxy resins; UV curable epoxy resins; Examples thereof include silicone resins such as hydrogenated silicone resins; polymers produced from benzocyclobutene.
[0057]
When the microlens is disposed at the end of the optical signal transmission optical path, it may be disposed at the end of the optical signal transmission optical path via a transparent adhesive layer. When the resin layer is formed, it may be directly disposed on the optical path resin layer.
Similarly, when the microlens is disposed at the end of the optical path opening, it may be disposed at the end of the optical path opening via a transparent adhesive layer. When a layer is formed, it may be directly disposed on the optical path resin layer.
[0058]
The mounting position of the microlens is limited to the end portion on the sealing resin layer side (side facing the multilayer printed wiring board) of the optical signal transmission optical path formed on the IC chip mounting substrate, but is limited thereto. The optical signal transmission optical path may be attached to the end of the optical element side, or may be attached to both ends of the optical signal transmission optical path.
The shape of the microlens is not limited to the convex lens as shown in FIG. 2, and may be any shape that can collect an optical signal in a desired direction.
[0059]
Next, other components of the optical communication device of the present invention will be described.
An optical element (light receiving element, light emitting element) is mounted on the IC chip mounting substrate constituting the device for optical communication of the present invention.
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 optical communication device, 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.
[0060]
Examples of the light emitting element include LD (semiconductor laser), DFB-LD (distributed feedback type-semiconductor laser), LED (light emitting diode), and the like.
These may be properly used in consideration of the configuration and required characteristics of the optical communication device.
[0061]
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.
The periphery of the optical element mounted on the IC chip mounting substrate may be resin-sealed. Further, a space between the mounted optical element and the solder resist layer or the optical path resin layer may be resin-sealed. In this case, the resin sealing is, for example, the same material as the material of the sealing resin layer. What is necessary is just to be performed using.
[0062]
Further, an optical path for optical signal transmission is formed on the IC chip mounting substrate constituting the optical communication device of the present invention, the optical element mounted on the IC chip mounting substrate, and the multilayer printed wiring board. An optical signal can be transmitted to and from the optical waveguide formed on the optical path via the optical signal transmission optical path.
[0063]
The optical signal transmission optical path preferably has an optical path resin layer formed therein. The formation of the optical path resin layer in this manner is suitable for forming the sealing resin layer as described above, and dust or foreign matter enters between the optical element and the optical waveguide. This is because there is less fear.
Further, when the optical path resin layer is formed inside the optical signal transmission optical path, the strength of the IC chip mounting substrate is also excellent.
In some cases, a part or all of the inside of the optical path for transmitting an optical signal may be constituted by a gap.
[0064]
Further, when the optical path resin layer is formed inside the optical path for optical signal transmission, the resin component is not particularly limited as long as the resin component has little absorption in the communication wavelength band. Examples thereof include those similar to the resin used for the sealing resin layer.
In addition to the resin component, the resin layer for an optical path 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 signal transmission optical path and the substrate, the interlayer resin insulating layer, the solder resist layer, or the like.
Specific examples of the particles include the same particles as those contained in the sealing resin layer.
[0065]
Further, the shape of the optical path for transmitting an optical signal is not particularly limited, and examples thereof include a cylindrical shape, an elliptical column shape, a quadrangular column shape, and a polygonal column shape. Of these, a cylindrical shape is desirable. This is because the formation is easy.
[0066]
The desirable lower limit of the diameter of the cross section of the optical signal transmission optical path is 100 μm. If the diameter of the cross section is less than 100 μm, the optical path may be blocked and it may be difficult to form an optical path resin layer inside the optical signal transmission optical path. On the other hand, the desirable upper limit of the diameter of the cross section is 500 μm. This is because even if the thickness is larger than 500 μm, the transmission property of the optical signal is not improved so much, which may hinder the degree of freedom in designing the conductor circuit formed on the IC chip mounting substrate.
The diameter of the cross-section is more excellent in terms of optical signal transmission and design freedom, and the more desirable lower limit is 250 μm because no inconvenience occurs when filling an uncured resin composition. There is a more desirable upper limit of 350 μm. The diameter of the cross section of the optical path for optical signal transmission is the diameter of the cross section when the optical path for optical signal transmission is cylindrical, the long diameter of the cross section when the optical path is elliptical, or the shape of a quadrangular prism or polygonal cylinder In some cases, it refers to the length of the longest part of the cross section.
[0067]
The optical path for transmitting an optical signal preferably has a conductor layer formed on its wall surface, and the conductor layer may be composed of one layer or may be composed of 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 interlayer resin insulation layer. be able to.
The material of the conductor layer may be a glossy metal such as gold, silver, nickel, platinum, aluminum, or rhodium. In the conductor layer formed using such a glossy metal, the optical signal is preferably reflected.
[0068]
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 or the roughening layer, the adhesion between the optical path for transmitting an optical signal and the resin layer for the optical path can be improved.
[0069]
Further, when a conductor layer or an optical path resin layer is formed inside the optical signal transmission optical path, these may be in contact with a substrate or an interlayer resin insulating layer via a roughened surface. This is because, when the conductor layer is in contact with the roughened surface, the adhesiveness with the substrate and the interlayer resin insulating layer is excellent, and peeling of the conductor layer and the like is less likely to occur.
[0070]
An optical waveguide is formed on the multilayer printed wiring board constituting the optical communication device of the present invention.
Examples of the optical waveguide include an organic optical waveguide made of a polymer material and the like, an inorganic optical waveguide made of quartz glass, a compound semiconductor, and 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 with the interlayer resin insulation layer and is easy to process.
[0071]
The polymer material is not particularly limited as long as it has low 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 sensitized. Resin, a composite of a thermosetting resin and a thermoplastic resin, a composite of a photosensitive resin and a thermoplastic resin, and the like.
[0072]
Specifically, for example, 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, Examples thereof include silicone resins such as deuterated silicone resins, polymers produced from benzocyclobutene, and the like.
[0073]
In addition to the resin component, the optical waveguide may contain particles such as resin particles, inorganic particles, and metal particles.
Specific examples of the particles include the same particles as those contained in the sealing resin layer.
[0074]
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 spherical or elliptical particles have no corners, so that cracks and the like are less likely to occur in the optical waveguide.
Furthermore, when the shape of the particles is spherical or elliptical, light is not easily reflected by the particles, and the loss of optical signals is reduced.
[0075]
The desirable lower limit of the particle size of the particles is 0.01 μm, and the more desirable lower limit is 0.1 μm. On the other hand, the desirable upper limit of the particle size is 100 μm, and the more desirable upper limit is 50 μm. In particular, the upper limit is desirably shorter than the communication wavelength. This is because if the average particle size of the particles is shorter than the communication wavelength, there is less possibility that the transmission of the optical signal will be hindered.
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.
[0076]
A desirable lower limit of the amount of the particles contained in the optical waveguide is 10% by weight, and a more desirable lower limit is 20% by weight. On the other hand, the desirable upper limit of the compounding amount 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. Is
The shape of the optical waveguide is not particularly limited, but a sheet shape is desirable because it is easy to form.
[0077]
When particles are contained in the optical waveguide in this way, the thermal expansion coefficient can be matched between the optical waveguide and the substrate or interlayer resin insulation layer constituting the multilayer printed wiring board. Cracks and peeling due to the difference are less likely to occur.
[0078]
The thickness 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. .
[0079]
The ratio between the thickness and width of the optical waveguide is preferably 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. Note that the ratio of the thickness to the width is not particularly limited, and may be about 1: 2 to about 2: 1.
Further, when the optical waveguide is a single mode optical waveguide having a communication wavelength of 1.55 μm, the thickness and width are preferably 5 to 15 μm, and the optical waveguide has a communication wavelength of 0.85 μm and a multimode. In the case of an optical waveguide, the thickness and width are preferably 20 to 80 μm.
[0080]
Further, as the optical waveguide, it is desirable that a light receiving optical waveguide and a light emitting optical waveguide are formed. The light receiving optical waveguide refers to an optical waveguide for transmitting an optical signal transmitted from the outside via an optical fiber or the like to the light receiving element. The light emitting optical waveguide is transmitted from the light emitting element. An optical waveguide for transmitting a received optical signal to an optical fiber or the like.
The light receiving optical waveguide and the light emitting optical waveguide are preferably made of the same material. This is because the thermal expansion coefficient and the like are easily matched and easy to form.
[0081]
As described above, an optical path conversion mirror is preferably 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, for example, by cutting one end of the optical waveguide, as will be described later.
[0082]
In the multilayer printed wiring board shown in FIGS. 1 and 2, the optical waveguide is formed on the outermost interlayer resin insulating layer on the side facing the IC chip mounting substrate. The formation position of the optical waveguide in is not limited to this, and may be between the interlayer resin insulation layers or between the substrate and the interlayer resin insulation layer. Furthermore, it is on the outermost interlayer resin insulation layer on the side facing the IC chip mounting substrate and on the opposite side across the substrate, between the interlayer resin insulation layers, between the substrate and the interlayer resin insulation layer, etc. May be.
[0083]
That is, the optical waveguide is formed on the interlayer resin insulation layer on the outermost layer on the opposite side across the substrate and the side facing the IC chip mounting substrate of the multilayer printed wiring board as in the optical communication device shown in FIG. May be.
FIG. 14 is a cross-sectional view schematically showing an embodiment of an optical communication device of the present invention.
Similarly to the optical communication device 150 shown in FIG. 1, the optical communication device 350 shown in FIG. 14 includes an IC chip mounting substrate 320 and a multilayer printed wiring board 300. The wiring board 300 is electrically connected via a solder connection portion 337.
Further, a sealing resin layer 360 is formed between the IC chip mounting substrate 320 and the multilayer printed wiring board 300.
[0084]
The configuration of the IC chip mounting substrate 320 is substantially the same as the configuration of the IC chip mounting substrate 120 shown in FIG.
In the multilayer printed wiring board 300, the conductor circuit 304 and the interlayer resin insulating layer 302 are laminated on both surfaces of the substrate 301, the conductor circuits sandwiching the substrate 301, and the conductor circuit sandwiching the interlayer resin insulating layer 302. The two are electrically connected by a through hole 309 and a via hole 307, respectively. Further, a solder resist layer 314 having solder bumps is formed on the outermost layer of the multilayer printed wiring board.
An optical waveguide 318 having an optical path conversion mirror 319 is formed on the outermost interlayer resin insulating layer on the opposite side of the substrate 301 and the side facing the IC chip mounting substrate 320 of the multilayer printed wiring board 300. The substrate 301, the interlayer resin insulation layer 302, and the optical waveguide 318 and the optical path 341 for optical signal transmission formed on the IC chip mounting substrate 320 can be transmitted. An optical signal transmission optical path 352 penetrating the solder resist layer 314 on the side facing the IC chip mounting substrate is formed.
The optical signal transmission optical path 351 has a conductor layer 355 formed on its wall surface and an optical path resin layer 352 formed therein. These conductor layer and optical path resin layer may be formed as necessary. What is necessary is just to form.
In the optical communication device having such a configuration, an optical signal can be transmitted through an optical signal transmission optical path 351 formed on the multilayer printed wiring board 300.
[0085]
In the multilayer printed wiring board constituting the device for optical communication shown in FIGS. 1, 2, and 14, an optical waveguide is formed on the outermost interlayer resin insulation layer, and the interlayer resin insulation layer and the optical waveguide are further formed. The solder resist layer is formed so as to cover, but the solder resist layer is not necessarily formed. For example, an optical waveguide is formed on the entire outermost interlayer resin insulating layer, and the optical waveguide is You may play the role as a soldering resist layer.
The optical communication device of the present invention having such a configuration can be manufactured, for example, by the method for manufacturing an optical communication device of the present invention described later.
[0086]
Next, the manufacturing method of the device for optical communication of this invention is demonstrated.
An optical communication device manufacturing method according to the present invention includes: an optical chip for optical signal transmission; an IC chip mounting substrate on which an optical element is mounted on one surface; and a multilayer printed wiring including at least an optical waveguide After manufacturing the board separately,
Between the optical element of the IC chip mounting substrate and the optical waveguide of the multilayer printed wiring board, both are arranged and fixed at a position where an optical signal can be transmitted,
Further, a sealing resin layer is formed by pouring a sealing resin composition between the IC chip mounting substrate and the multilayer printed wiring board, followed by curing treatment.A method of manufacturing a device for optical communication,
When forming the optical path for optical signal transmission, the optical chip is formed so as to penetrate the IC chip mounting substrate, and an optical path resin layer is formed therein, and the multilayer print of the optical path for optical signal transmission is further formed. A microlens having a refractive index larger than that of the sealing resin layer is disposed at an end portion facing the wiring board.
[0087]
In the method for manufacturing an optical communication device of the present invention, an IC chip mounting substrate and a multilayer printed wiring board are arranged and fixed at predetermined positions, and then a sealing resin layer is formed between them. It is possible to suitably manufacture an optical communication device in which dust and foreign matters floating in the air do not enter between the optical waveguide and the transmission of optical signals is not hindered.
[0088]
Further, by forming a sealing resin layer between the IC chip mounting substrate and the multilayer printed wiring board, in the obtained optical communication device, the sealing resin layer is the above IC chip mounting substrate and the above It can play the role of relieving the stress generated due to the difference in thermal expansion coefficient with the multilayer printed wiring board, and the formation of the sealing resin layer can shift the position of the optical element and optical waveguide. Less likely to occur.
Therefore, in the manufacturing method of the present invention, an optical communication device having excellent reliability can be preferably manufactured.
[0089]
In the method for manufacturing an optical communication device, first, an IC chip mounting substrate and a multilayer printed wiring board are separately manufactured.
Therefore, here, first, a method for manufacturing an IC chip mounting substrate and a method for manufacturing a multilayer printed wiring board will be described separately, and then a method for forming a sealing resin layer will be described.
[0090]
First, a method for manufacturing an IC chip mounting substrate will be described.
(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 resin (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.
[0091]
In addition, in the case where connection between conductor circuits sandwiching the insulating substrate is performed through holes, for example, after forming a through hole in the insulating substrate using a drill or a laser, an electroless plating process or the like is performed. Through holes are formed by applying.
Further, when a through hole is formed, it is desirable to fill the through hole with a resin filler.
[0092]
(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.
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.
[0093]
(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 provided 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.
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.
[0094]
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.
[0095]
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.
[0096]
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.
[0097]
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.
[0098]
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. The specific combination of the thermosetting resin and the thermoplastic resin includes, for example, phenol resin / polyether sulfone, polyimide resin / polysulfone, epoxy resin / polyether sulfone, epoxy resin / phenoxy resin, and the like. It is done. Specific examples of the combination of the photosensitive resin and the thermoplastic resin include an acrylic resin / phenoxy resin, an epoxy resin in which a part of the epoxy group is acrylated, and polyether sulfone.
[0099]
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.
[0100]
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.
By adopting such a configuration, it is possible to ensure excellent adhesion with the insulating substrate, and it is possible to ensure ease of formation when forming a via hole opening or the like in a subsequent process.
[0101]
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.
[0102]
The heat-resistant resin matrix is preferably one that can maintain the shape of the roughened surface when the roughened surface is formed on the interlayer resin insulation layer using the roughening liquid, for example, a thermosetting resin. , Thermoplastic resins, and composites thereof. Further, a photosensitive resin may be used. In the case where a photosensitive resin is used, a via hole opening can be formed in the interlayer resin insulating layer by exposure and development processes.
[0103]
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.
[0104]
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.
[0105]
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.
[0106]
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.
[0107]
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 those composed of silicon compounds such as silica and zeolite. These may be used alone or in combination of two or more.
[0108]
Examples of the resin particles include those made of a thermosetting resin, a thermoplastic resin, and the like. 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 polyphenylene resin, polyolefin resin, fluororesin, and bismaleimide-triazine resin. 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 for dissolving the resin matrix.
Further, as the resin particles, rubber particles, liquid phase resin, liquid phase rubber, or the like may be used.
[0109]
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.
[0110]
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 interlayer resin insulation layer can be secured, and the thermal expansion can be easily adjusted with the hardly soluble resin, and the interlayer resin made of the roughened surface-forming resin composition This is because no crack occurs in the insulating layer, and no peeling occurs between the interlayer resin insulating layer and the conductor circuit.
[0111]
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 the conductor circuit exposed from the bottom surface of the via hole is less likely to be corroded when roughened.
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.
[0112]
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.
[0113]
Thus, by combining average particles, relatively large coarse particles, and fine particles having a relatively small average particle diameter, the dissolution residue of the electroless plating film 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.
[0114]
(4) Next, when forming an interlayer resin insulation layer using a thermosetting resin or resin composite as the material, the uncured resin insulation layer is cured and a via hole opening is formed. And an interlayer resin insulation layer. In this step, a through hole 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 for the interlayer resin insulation layer, it may be formed by exposure and development processing.
[0115]
When an interlayer resin insulating layer using a thermoplastic resin as the material is formed, a via hole opening is formed in the resin layer made of the thermoplastic resin to form an interlayer resin insulating layer. In this case, the via hole opening can be formed by performing laser treatment.
Further, when forming a through hole in this step, the through hole may be formed by drilling or laser processing.
[0116]
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.
[0117]
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 openings are formed in the resin film layer by one irradiation. Can be formed efficiently.
[0118]
When a carbon dioxide laser is used, the pulse interval is 10^-Four-10^-8It is desirable to be 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 a plurality of portions can be irradiated with laser light having the same intensity and the same irradiation intensity through the optical system lens and the mask.
After forming the via hole opening in this manner, desmear treatment may be performed as necessary.
[0119]
(5) Next, a conductor circuit is formed on the surface of the interlayer resin insulation 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 interlayer resin insulation layer.
The thin film conductor layer can be formed by a method such as electroless plating or sputtering.
[0120]
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.
The thickness of the thin film conductor layer is preferably 0.3 μm, more preferably 0.6 μm, and preferably 2.0 μm, when the thin film conductor layer is formed by electroless plating. A desirable upper limit is 1.2 μm. Moreover, when forming by sputtering, 0.1-1.0 micrometer is desirable.
[0121]
In addition, a roughened surface may be formed on the surface of the interlayer resin insulation layer before forming the thin film conductor layer. By forming the roughened surface, the adhesion between the interlayer resin insulation layer and the thin film conductor layer can be improved. In particular, when an interlayer resin insulation layer is formed using a roughened surface forming resin composition, it is desirable to form a roughened surface using an acid, an oxidizing agent, or the like.
[0122]
Further, when the through hole is formed in the step (4), when the thin film conductor layer is formed on the interlayer resin insulation layer, the through hole is formed by forming the thin film conductor layer on the wall surface of the through hole. Also good.
[0123]
(6) Next, a plating resist is formed on the substrate on which the thin film conductor layer is formed.
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.
[0124]
(7) Thereafter, electroplating is performed using the thin film conductor layer as a plating lead, and an electroplating layer is formed in the plating resist non-forming portion. As the electroplating, copper plating is desirable.
The thickness of the electroplating layer is preferably 5 to 20 μm.
[0125]
Then, a conductor circuit (including a via hole) can be formed by removing the plating resist, the electroless plating film 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 interlayer resin insulation layer using an acid or an oxidizing agent as needed. This is because deterioration of electrical characteristics can be prevented.
[0126]
The method for forming a conductor circuit described here is an additive method, but the method for forming a conductor circuit in the manufacturing method of the present invention is not limited to the additive method, for example, a subtractive method. Also good.
Hereinafter, a method for forming a conductor circuit by the subtractive method will be briefly described.
[0127]
That is, first, after forming an interlayer resin insulating layer having a via hole opening, a thin film conductor layer is formed on the surface of the interlayer resin insulating layer including the wall surface of the via hole opening in the same manner as in the step (5). Form.
[0128]
Next, the thickness of the conductor layer is increased by forming an electroplating layer or the like on the entire surface of the thin film conductor layer. In addition, what is necessary is just to perform formation of an electroplating layer etc. as needed.
Next, an etching resist is formed on the conductor layer.
The etching resist is formed, for example, by pasting a photosensitive dry film, placing a photomask in close contact with the photosensitive dry film, and performing exposure development processing.
[0129]
Further, the conductor layer under the etching resist non-forming portion is removed by etching, and then the etching resist is removed to form independent conductor circuits (including via holes) on the interlayer resin insulating layer.
The etching treatment can be performed using, for example, an etching solution such as a mixed solution of sulfuric acid and hydrogen peroxide, sodium persulfate, ammonium persulfate, ferric chloride, and cupric chloride. Peeling can be performed using an alkaline aqueous solution or the like.
Even when such a method is used, a conductor circuit can be formed on the interlayer resin insulation layer.
[0130]
Whether the additive method or the subtractive method is selected as the method of forming the conductor circuit depends on the width and interval of the conductor circuit, the mounting terminals of IC chips and optical elements to be mounted, and other various electronic components. What is necessary is just to select suitably in consideration of a number, a pitch, etc.
[0131]
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 portion of the resin filler layer may be formed by performing electroless plating, if necessary.
[0132]
(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 outer interlayer resin insulation layer can be formed.
[0133]
(9) Thereafter, by repeating the steps (3) to (8) as necessary, a conductor circuit and an interlayer resin insulating layer are laminated on both surfaces. In this step, a through hole may be formed or may not be formed.
By performing such steps (1) to (9), it is possible to manufacture a multilayer wiring board in which a conductor circuit and an interlayer resin insulating layer are laminated on both surfaces of a substrate.
[0134]
(10) Next, a through-hole penetrating the multilayer wiring board is formed. The through hole formed here becomes an optical path for optical signal transmission in the IC chip mounting substrate through a subsequent process. Therefore, the through hole formed in this step is hereinafter referred to as an optical path through hole.
[0135]
The optical path through hole is formed by, for example, drilling or laser processing.
Examples of the laser used in the laser treatment include the same lasers used in the formation of the via hole openings and the formation of the solder bump formation openings.
The formation position of the through hole for the optical path is not particularly limited, and may be appropriately selected in consideration of the design of the conductor circuit, the mounting position of the optical element, the IC chip, and the like.
Further, it is desirable that the optical path through hole is formed for each optical element such as a light receiving element or a light emitting element. Moreover, you may form for every signal wavelength.
[0136]
Moreover, after forming the through-hole for optical paths, you may perform a desmear process as needed.
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, it is possible to remove resin residue, burrs, and the like in the optical path through-hole, and to reduce transmission loss due to irregular reflection on the wall surface of the optical signal transmission optical path.
[0137]
In addition, after forming the through hole for the optical path, before forming a conductor layer on the wall surface or filling an uncured resin composition in the interior in the following process, if necessary, A roughened surface may be formed on the wall surface. This is because the formation of the roughened surface can improve the adhesion to the conductor layer and the resin composition.
The roughened surface is formed by, for example, forming an optical path through hole such as a substrate or an interlayer resin insulation layer with an acid such as sulfuric acid, hydrochloric acid or nitric acid; an oxidizing agent such as chromic acid, chromium sulfuric acid or permanganate. This can be done by dissolving the exposed portion. It can also be performed by plasma treatment, corona treatment, or the like.
[0138]
In addition, after forming the optical path through hole, it is desirable to form a conductor layer on the wall surface of the optical path through hole.
The conductor layer can be formed, for example, by a method such as electroless plating or sputtering.
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.
[0139]
In this step, it is desirable to form a conductor layer on the wall surface of the through hole for the optical path and to form an outermost layer conductor circuit on the outermost interlayer resin insulation layer of the multilayer wiring board.
Specifically, first, when the conductor layer is 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 interlayer resin insulating layer.
[0140]
Next, a plating resist is formed on the conductor layer formed on the surface of the interlayer resin insulation layer. For example, the plating resist may be formed by a method similar to the method performed in the step (6).
[0141]
Further, electrolytic plating is performed using the conductor layer formed on the interlayer resin insulation layer as a plating lead, and an electroplating 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 interlayer resin insulation layer.
[0142]
Further, after forming the conductor layer, a roughened surface may be formed on the wall surface of the conductor layer. The roughened surface may be formed by, for example, a method similar to the method performed in the step (2).
[0143]
In addition, after forming the optical path through hole (after forming a conductor layer on the wall surface as necessary), it is desirable to fill the uncured resin composition in the optical path through hole. An optical path for optical signal transmission in which an optical path resin layer is formed can be obtained by performing a curing process after filling with an uncured resin composition.
The method for filling the uncured resin composition is not particularly limited, and for example, a method such as printing or potting can be used.
In addition, when filling the uncured resin composition by printing, the resin composition may be filled once, or may be printed dividedly twice or more. Also, printing may be performed from both sides of the multilayer wiring board.
[0144]
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, and is appropriately determined in consideration of the material of the resin composition and the like. Just choose.
[0145]
By performing such a process, an optical path for transmitting an optical signal that penetrates the multilayer wiring board can be formed.
When the conductor layer is formed on the wall surface of the through hole for the optical path, an independent conductor circuit can be formed by forming the conductor layer on the surface of the interlayer resin insulating layer and performing the above-described processing. Of course, even when the conductor layer is not formed, an independent conductor circuit may be formed on the interlayer resin insulating layer by the above-described method.
[0146]
(11) Next, a solder resist layer is formed on the outermost layer of the substrate on which the conductor circuit and the interlayer resin insulating layer are formed.
The solder resist layer 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.
[0147]
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 may also be used.
Moreover, at this process, you may pressure-bond the film which consists of the said soldering resist composition, and may form the layer of a soldering resist composition.
[0148]
(12) Next, an opening (hereinafter also referred to as an optical path opening) communicating with the optical path through hole is formed in the solder resist composition layer to form a solder resist layer.
Specifically, for example, it is formed by the same method as the method of forming the via hole opening, that is, exposure development processing, laser processing, or the like.
When forming the optical path opening, a solder bump forming opening (an opening for mounting an IC chip or an optical element or an opening for connecting to a multilayer printed wiring board) may be formed at the same time. desirable. The formation of the optical path opening and the formation of the solder bump forming opening may be performed separately.
[0149]
Moreover, when forming a 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 (11) and (12), a solder resist layer having an 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. .
The diameter of the optical path opening may be the same as the diameter of the optical path through hole, or may be smaller than the diameter of the optical path through hole.
[0150]
Further, when the optical path resin layer is formed in the optical path through hole in the step (10), the uncured resin composition is filled in the optical path opening in this process, and then the curing process is performed. It is desirable to form an optical path resin layer by applying.
Also in this step, by forming the optical path resin layer, the optical path resin layer is formed in the entire interior of the optical signal transmission optical path.
Further, the uncured resin composition filled in the optical path opening is preferably the same as the uncured resin composition filled in the optical path through hole in the step (10). .
[0151]
In addition, when forming an optical path for transmitting an optical signal in which an optical path resin layer is formed in the entire interior, in the step (10), filling with an uncured resin composition is not performed. For optical signal transmission in which an uncured resin composition is filled in an optical path through-hole and an optical path opening communicating with the optical path through which the optical path resin layer is formed. It may be an optical path.
[0152]
In the step (10), after filling the optical path through hole with an uncured resin composition, the resin composition is semi-cured, and then the solder resist layer having the optical path opening by the method described above. After forming and further filling the uncured resin composition in the optical path opening, by simultaneously curing the resin composition in the optical path through hole and the resin composition in the optical path opening, An optical path resin layer may be formed.
[0153]
(13) Next, if necessary, a microlens is disposed at the end of the optical signal transmission optical path.
In order to dispose the microlens at the end of the optical signal transmission optical path, it may be disposed at the end of the optical signal transmission optical path through an adhesive layer formed on the solder resist layer. When the optical path resin layer is formed inside the optical signal transmission optical path, the optical path resin layer may be directly disposed on the optical path resin layer or may be disposed through a transparent adhesive layer. .
[0154]
As a method of directly arranging the microlens on the optical path resin layer, for example, an appropriate amount of uncured optical lens resin is dropped on the optical path resin layer, and cured to the dropped uncured optical lens resin. The method of performing a process etc. are mentioned.
When an appropriate amount of the uncured optical lens resin is dropped onto the optical path resin layer, a device such as a dispenser, an ink jet, a micropipette, or a microsyringe can be used.
The uncured optical lens resin dropped on the optical path resin layer using such an apparatus tends to be spherical due to its surface tension, and thus becomes hemispherical on the optical path resin layer, and then hemispherical. By curing the uncured optical lens resin, a hemispherical microlens (convex lens) can be disposed on the optical path resin layer.
In addition, the diameter of the microlens formed by the above-mentioned method, the shape of the curved surface, etc. are appropriately determined in consideration of the wettability between the resin composition and the uncured optical lens resin, the viscosity of the uncured optical lens resin, etc. It can be controlled by adjusting.
[0155]
(14) Next, the conductor circuit portion exposed by forming the solder bump forming opening is covered 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.
[0156]
(15) Next, an opening is formed in a portion corresponding to an opening for mounting an IC chip (IC chip mounting opening) or an opening for connecting to a multilayer printed wiring board (multilayer printed wiring board connection opening). A solder bump is formed by reflowing after filling the solder pad with a solder paste through the formed mask.
By forming such solder bumps, it is possible to mount an IC chip or connect a multilayer printed wiring board via the solder bumps. The solder bumps may be formed as necessary. Even when the solder bumps are not formed, these solder bumps can be mounted on the IC chip via the IC chip to be mounted or the bump of the multilayer printed wiring board to be connected. The substrate can be electrically connected.
[0157]
(16) Further, an optical element (light receiving element and light emitting element) is mounted on the solder resist layer. The optical element is mounted by, for example, filling the opening (optical element mounting opening) for mounting the optical element in the step (15) with solder paste and performing the reflow. What is necessary is just to mount via solder by attaching an element.
Further, the optical element may be mounted using a conductive adhesive or the like instead of the solder paste.
Through such steps, an IC chip mounting substrate constituting the optical communication device of the present invention can be manufactured.
[0158]
Next, the manufacturing method of a multilayer printed wiring board is demonstrated.
(1) First, in the same manner as the steps (1) to (2) of the method for manufacturing an IC chip mounting substrate, conductor circuits are formed on both surfaces of the substrate and the conductor circuits sandwiching the substrate are connected. Form a through hole. 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.
[0159]
(2) Next, if necessary, an interlayer resin insulation layer and a conductor circuit are laminated on the substrate on which the conductor circuit is formed.
Specifically, the interlayer resin 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 the IC chip mounting substrate.
Also in this step, as in the case of manufacturing an IC chip mounting substrate, a through hole penetrating the substrate and the interlayer resin insulating layer may be formed, or a lid plating layer may be formed.
The step (2), that is, the step of laminating the interlayer resin insulation layer and the conductor circuit may be performed only once or a plurality of times.
Further, as a method for forming a conductor circuit on the interlayer resin insulation layer in this step, a subtractive method may be used as in the case of manufacturing an IC chip mounting substrate.
[0160]
(3) Next, an optical waveguide is formed on the substrate on the side facing the IC chip mounting substrate or on the conductor circuit non-forming portion on the interlayer resin insulation layer.
When the optical waveguide is formed by 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 is, for example, LiNbO._ThreeLiTaO_ThreeIt can be formed by depositing an inorganic material such as a liquid phase epitaxial method, a chemical deposition method (CVD), a molecular beam epitaxial method, or the like.
[0161]
In addition, as a method for forming an optical waveguide made of a polymer material, for example, (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 interlayer resin insulating layer And (2) a method of directly forming an optical waveguide on the interlayer resin insulation layer by sequentially forming a lower clad, a core, and an upper clad on the interlayer resin insulation layer.
As a method for forming the optical waveguide, the same method can be used when the optical waveguide is formed on the release film and when the optical waveguide is formed on the interlayer resin insulating layer.
Specifically, for example, 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.
[0162]
In the method using reactive ion etching, (i) first, a lower cladding is formed on a release film, an interlayer resin insulation layer or the like (hereinafter simply referred to as a release film), and (ii) A core resin composition is applied onto the lower 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.
[0163]
(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.
[0164]
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.
[0165]
(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.
[0166]
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.
[0167]
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.
[0168]
(Iii) Next, by applying the resin composition for the core to the non-resist forming portion on the lower clad, and (iv) further curing the core resin composition, and then peeling the core forming resist, 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.
As this resist forming method, this mold forming method can be suitably used when mass-producing optical waveguides, and an optical waveguide having excellent dimensional reliability can be formed. This method is also excellent in reproducibility.
[0169]
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 interlayer resin insulation layer, or may be formed after the optical waveguide is mounted on the interlayer resin insulation layer. Except for the case where it is directly formed on the layer, it is desirable to form an optical path conversion mirror in advance. The work can be performed easily, and other members constituting the multilayer printed wiring board at the time of the work, such as a substrate, a conductor circuit, an interlayer resin insulating layer, etc., may be scratched or damaged. Because there is no.
[0170]
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.
Here, the method for forming the optical waveguide on the substrate on the side facing the IC chip mounting substrate or on the outermost interlayer resin insulation layer has been described, but in the case of manufacturing the multilayer printed wiring board, The optical waveguide may be formed between the substrate and the interlayer resin insulation layer or between the interlayer resin insulation layers.
[0171]
In the case of forming an optical waveguide between the substrate and the interlayer resin insulation layer, after producing a substrate having conductor circuits formed on both surfaces in the step (1), the same as in the step (3). An optical waveguide is formed at the above-mentioned position by forming an optical waveguide at a portion where a conductor circuit is not formed on the substrate by the method, and then forming an interlayer resin insulating layer by the same method as in the step (2). be able to.
[0172]
When an optical waveguide is formed between the interlayer resin insulation layers, at least one interlayer resin insulation layer is formed on the substrate on which the conductor circuit is formed in the same manner as in the steps (1) and (2). Then, an optical waveguide is formed on the interlayer resin insulation layer in the same manner as in the above step (3), and then the same step as in the above step (2) is further repeated to obtain an interlayer resin insulation. An optical waveguide can be formed between the layers.
[0173]
Further, in the multilayer printed wiring board constituting the optical communication device of the present invention, an optical waveguide may be formed on the side facing the IC chip mounting substrate and on the opposite side across the substrate. When manufacturing a multilayer printed wiring board in which an optical waveguide is formed, an optical signal can be transmitted between the optical waveguide and an optical element mounted on the IC chip mounting substrate. However, it is necessary to form at least an optical path for transmitting an optical signal that penetrates the substrate. Such an optical path for transmitting an optical signal may be appropriately formed before the optical waveguide is formed or after the optical waveguide is formed. .
[0174]
Specifically, for example, (10) of the method for manufacturing a substrate for mounting an IC chip after forming a multilayer wiring board through the steps (1) and (2) and before forming an optical waveguide. Using the same method as in the above step, the optical path through hole is formed, and then the optical signal can be transmitted to the IC chip mounting substrate through the optical path through hole. An optical waveguide may be formed by a method, and a multilayer printed wiring board may be obtained through the steps described below. In addition, after forming the said through-hole for optical paths, you may form the resin layer for optical paths, and a conductor layer in the inside or wall surface as needed.
[0175]
(4) Next, a solder resist layer is formed on the outermost layer of the substrate on which the optical waveguide is formed.
The solder resist layer can be formed using, for example, a resin composition similar to the resin composition used when forming the solder resist layer of the IC chip mounting substrate.
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.
[0176]
(5) Next, an opening for forming solder bumps (an opening for mounting an IC chip mounting substrate and various surface mount electronic components) and an optical path opening on the solder resist layer on the side facing the IC chip mounting substrate Form.
The formation of the solder bump forming opening and the optical path opening may be performed using a method similar to the method of forming the solder bump forming opening on the IC chip mounting substrate, that is, using an exposure development process or a laser process. it can.
The formation of the solder bump formation opening and the formation of the optical path opening may be performed simultaneously or separately.
[0177]
Among these, when forming the solder resist layer, a method of forming a solder bump forming opening and an optical path opening by applying a resin composition containing a photosensitive resin as a material and performing an exposure development process. It is desirable to select.
This is because when the optical path opening is formed by exposure and development processing, there is no possibility of scratching the optical waveguide existing under the optical path opening when the opening is formed.
Moreover, when forming a solder resist layer, a solder resist layer having a solder bump forming opening and an optical path opening is prepared in advance by preparing a resin film having an opening at a desired position and pasting the resin film. May be formed.
When the optical path through hole is formed and the optical waveguide is formed on the side facing the IC chip mounting substrate and the opposite side of the substrate, the optical path opening is formed when forming the optical path opening in this step. The opening is formed so as to communicate with the optical path through hole.
[0178]
If necessary, solder bump forming openings may also be formed in the solder resist layer on the side opposite to the surface facing the IC chip mounting substrate.
This is because the external connection terminals can also be formed on the solder resist layer on the opposite side of the surface facing the IC chip mounting substrate through the post-process.
[0179]
(6) Next, 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, or platinum as necessary to form a solder pad. . Specifically, the same method as the step (14) of the method for manufacturing the IC chip mounting substrate may be used.
[0180]
(7) Next, if necessary, the optical path opening formed in the step (5) is filled with an uncured resin composition, and then cured to form an optical path resin layer. To do.
The uncured resin composition filled in this step is preferably the same as the resin composition filled in the optical path through hole and the optical path opening in the manufacturing process of the IC chip mounting substrate.
Further, as described above, even when the optical path through hole and the optical path opening are formed in order to form the optical waveguide on the side facing the IC chip mounting substrate and the opposite side across the substrate, the optical path The through-hole for use and the optical path opening may be filled with an uncured resin composition. In this case, as a method of filling the uncured resin composition, it is used when manufacturing an IC chip mounting substrate. A method similar to the method may be used.
[0181]
(8) Next, 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.
By forming such solder bumps, it is possible to mount an IC chip mounting substrate and various surface-mounted electronic components via the solder bumps. The solder bumps may be formed as necessary. Even when the solder bumps are not formed, these solder bumps are mounted via the IC chip mounting substrate to be mounted and the bumps of various surface mount electronic components. be able to.
Also, the solder resist layer on the opposite side of the surface facing the IC chip mounting substrate does not require the formation of external connection terminals, and pins or solder balls are formed as necessary. It is good also as PGA (Pin Grid Array) and BGA (Ball Grid Array).
Through such steps, an IC chip mounting substrate constituting the optical communication device of the present invention can be manufactured.
[0182]
In the method for manufacturing an optical communication device of the present invention, next, an optical signal transmission optical path formed on the IC chip mounting substrate is formed between the optical element of the IC chip mounting substrate and the optical waveguide of the multilayer printed wiring board. Both are arranged and fixed at a position where the optical signal can be transmitted through.
Here, after the IC chip mounting substrate and the multilayer printed wiring board are disposed to face each other, a solder connection portion is formed by the solder bumps of the IC chip mounting substrate and the solder bumps of the multilayer printed wiring board. It is electrically connected and both are fixed. In other words, the IC chip mounting substrate and the multilayer printed wiring board are arranged to face each other at a predetermined position in a predetermined direction, and are connected by reflowing.
As described above, the solder bumps for fixing both the IC chip mounting substrate and the multilayer printed wiring board may be formed on only one of them.
[0183]
In this process, since the IC chip mounting substrate and the multilayer printed wiring board are connected using their solder bumps, there is a slight misalignment between the two when they are placed opposite to each other. In addition, both can be arranged at a predetermined position due to the self-alignment effect of the solder during reflow.
[0184]
Next, a sealing resin composition is poured between the IC chip mounting substrate and the multilayer printed wiring board, and then a sealing resin layer is formed by performing a curing process.
Examples of the sealing resin composition include acrylic resins such as PMMA (polymethyl methacrylate), deuterated PMMA, and deuterated fluorinated PMMA; polyimide resins such as fluorinated polyimide; epoxy resins; UV curable epoxy resins Silicone resins such as deuterated silicone resins; resin components such as polymers produced from benzocyclobutene, and particles included as necessary, curing agents, antifoaming agents, acid anhydrides, solvents, etc. The various additives are appropriately blended.
In addition, the sealing resin composition preferably has a transmittance for light having a communication wavelength after curing of 70% or more, and more preferably 90% or more.
[0185]
Here, as the viscosity of the sealing resin composition poured between the IC chip mounting substrate and the multilayer printed wiring board and the curing treatment conditions after pouring the sealing resin composition, the sealing resin composition The composition may be appropriately selected in consideration of the composition of the substrate, the design of the IC chip mounting substrate and the multilayer printed wiring board, and the like.
[0186]
Next, the IC chip is mounted on the IC chip mounting substrate, and then, if necessary, the IC chip is resin-sealed to obtain an optical communication device.
The IC chip can be mounted by a conventionally known method.
Also, the IC chip is mounted before connecting the IC chip mounting substrate and the multilayer printed wiring board, and the optical chip is used for optical communication by connecting the IC chip mounting substrate on which the IC chip is mounted and the multilayer printed wiring board. It may be a device.
[0187]
【Example】
Hereinafter, the present invention will be described in more detail.
Example 1
A. Fabrication of IC chip mounting substrate
A-1. Preparation of resin film for interlayer resin insulation layer
30 parts by weight of bisphenol A type epoxy resin (epoxy equivalent 469, Epicoat 1001 manufactured by Yuka Shell Epoxy Co., Ltd.), 40 parts by weight of cresol novolac type epoxy resin (epoxy equivalent 215, Epiklon N-673 manufactured by Dainippon Ink & Chemicals, Inc.), triazine 30 parts by weight of a structure-containing phenol novolak resin (phenolic hydroxyl group equivalent 120, Phenolite KA-7052 manufactured by Dainippon Ink & Chemicals, Inc.) was dissolved in 20 parts by weight of ethyl diglycol acetate and 20 parts by weight of solvent naphtha with stirring. Thereto, terminal epoxidized polybutadiene rubber (Nagase Kasei Kogyo Denarex R-45EPT) 15 parts by weight, 2-phenyl-4,5-bis (hydroxymethyl) imidazole pulverized product 1.5 parts by weight, finely pulverized silica 2 parts by weight , Silicone It was added foaming agent 0.5 parts by weight to prepare an epoxy resin composition.
The obtained epoxy resin composition was applied 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 interlayer resin was obtained. A resin film for an insulating layer was produced.
[0188]
A-2. 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), SiO having an average particle diameter of 1.6 μm and a maximum particle diameter of 15 μm or less coated with a silane coupling agent on the surface₂170 parts by weight of spherical particles (manufactured by Adtech, CRS 1101-CE) and 1.5 parts by weight of a leveling agent (Perenol S4, manufactured by San Nopco) are placed in a container and mixed by stirring. A 49 Pa · s resin filler 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.
[0189]
A-3. Manufacture of IC chip mounting substrates
(1) A copper-clad laminate in which 18 μm copper foil 28 is laminated on both surfaces of an insulating substrate 21 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 0.8 mm was used as a starting material (see FIG. 3 (a)). 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 (FIG. 3B). reference).
[0190]
(2) The substrate on which the through hole 29 and the conductor circuit 24 are formed is washed with water and dried, followed by NaOH (10 g / l), NaClO.₂(40 g / l), Na₃PO₄Blackening treatment using an aqueous solution containing (6 g / l) as a blackening bath (oxidation bath), and NaOH (10 g / l), NaBH₄A reduction treatment using an aqueous solution containing (6 g / l) as a reduction bath was performed to form a roughened surface (not shown) on the surface of the conductor circuit 24 including the through holes 29.
[0191]
(3) After preparing the resin filler described in A-2 above, within 24 hours after preparation by the following method, the conductor circuit non-formed portion on the through hole 29 and the substrate 21 and the outer edge portion of the conductor circuit 24 And a layer of resin filler 30 '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 30 'was formed by drying for 20 minutes (see FIG. 3C).
[0192]
(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.
[0193]
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 (see FIG. 3D). By this step, the surface of the resin filler layer 30 and the surface of the conductor circuit 24 are flush with each other.
[0194]
(5) After washing the substrate with water, acid degreasing, soft etching, and spraying an etchant on both sides of the substrate by spraying to etch the surface of the conductor circuit 24 and the land surface of the through hole 29, 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.
[0195]
(6) Next, a resin film for an interlayer resin insulation layer that is slightly larger than the substrate prepared in A-1 is placed on the substrate, and temporarily mounted under conditions of a pressure of 0.4 MPa, a temperature of 80 ° C., and a pressure bonding time of 10 seconds. After crimping and cutting, an interlayer resin insulation layer 22 was further formed by sticking using a vacuum laminator apparatus by the following method (see FIG. 3E).
That is, a resin film for an interlayer resin insulation layer was subjected to main pressure bonding on a substrate under conditions of a degree of vacuum of 65 Pa, a pressure of 0.4 MPa, a temperature of 80, and a time of 60 seconds, and then thermally cured at 170 ° C. for 30 minutes.
[0196]
(7) Next, CO 2 having a wavelength of 10.4 μm is passed through a mask in which a through hole having a thickness of 1.2 mm is formed on the interlayer resin insulation layer 22.₂Via hole with a gas laser diameter of 4.0 mm, top hat mode, pulse width 8.0 μsec, mask through-hole diameter 1.0 mm, and interlayer resin insulation layer 22 with a diameter of 80 μm under conditions of one shot. 26 was formed (see FIG. 4A).
[0197]
(8) The substrate on which the via hole opening 26 is formed is immersed 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 interlayer resin insulating layer 22. As a result, a roughened surface (not shown) was formed on the surface including the inner wall surface of the opening 26 for the via hole.
[0198]
(9) Next, the substrate after the above treatment was immersed in a neutralization solution (manufactured by Shipley Co., Ltd.) and washed with water.
Further, by applying a palladium catalyst to the surface of the roughened substrate (roughening depth 3 μm), a catalyst nucleus is formed on the surface of the interlayer resin insulation layer 22 (including the inner wall surface of the via hole opening 26). Was attached (not shown). That is, the substrate is made of palladium chloride (PdCl₂) And stannous chloride (SnCl)₂The catalyst was imparted by immersing it in a catalyst solution containing) and depositing palladium metal.
[0199]
(10) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition, and the thickness of the surface of the interlayer resin insulating layer 22 (including the inner wall surface of the via hole opening 26) is 0.6 to 3 An electroless copper plating film 32 of 0.0 μm was formed (see FIG. 4B).
[0200]
[Electroless plating aqueous solution]
NiSO_Four                   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
[0201]
(11) Next, a commercially available photosensitive dry film is pasted on the substrate on which the electroless copper plating film 32 is formed, and a mask is placed thereon, and 100 mJ / cm.²Then, a plating resist 23 having a thickness of 20 μm was provided by developing with a 0.8% aqueous sodium carbonate solution (see FIG. 4C).
[0202]
(12) Next, the substrate is washed with 50 ° C. water and 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 23 non-formed portion. Then, an electrolytic copper plating film 33 having a thickness of 20 μm was formed (see FIG. 4D).
[0203]
[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 GL)
[Electrolytic plating conditions]
Current density 1 A / dm²
65 minutes
Temperature 22 ± 2 ° C
[0204]
(13) Further, after removing the plating resist 23 with 5% NaOH, the electroless plating film under the plating resist 23 is removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide, and electroless copper plating is performed. A conductor circuit 25 (including the via hole 27) having a thickness of 18 μm formed of the film 32 and the electrolytic copper plating film 33 was formed (see FIG. 5A).
[0205]
(14) Further, a roughened surface (not shown) is formed on the surface of the conductor circuit 25 using the same etching solution as the etching solution used in the step (5). In the same manner as in the step (8), an interlayer resin 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. 5B). .
Thereafter, using a drill having a diameter of 300 μm, an optical path through hole 46 penetrating the substrate 21 and the interlayer resin insulating layer 22 was formed, and further, a desmear treatment was applied to the wall surface of the optical path through hole 46 (FIG. 5C). )reference). In the present embodiment, the optical path through hole is formed using a drill having a diameter of 300 μm. However, when the optical path through hole is formed, a drill having a diameter of about 200 to 400 μm is usually used.
[0206]
(15) Next, a catalyst is applied to the wall surface of the optical path through-hole 46 and the surface of the interlayer resin insulation layer 22 by the same method as that used in the step (9). The substrate is immersed in an electroless copper plating aqueous solution similar to the electroless plating solution used in the process, the surface of the interlayer resin insulating layer 22 (including the inner wall surface of the via hole opening 26), and the optical path through hole A thin-film conductor layer (electroless copper plating film) 32 was formed on the wall surface 46 (see FIG. 6A).
[0207]
(16) Next, the plating resist 23 is provided by the same method as that used in the step (11), and further, the plating resist 23 is not formed by the same method as that 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. 6B).
[0208]
(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 25 (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 25 and the surface of the conductor layer 45 were roughened (not shown) (FIG. 6 ( c)).
[0209]
(18) Next, using a squeegee, the resin composition containing the epoxy resin was filled into the through hole 46 for the optical path in which the conductor layer 45 was formed, dried, and then the surface layer was flattened by buffing. . Furthermore, the hardening process was performed and the resin layer 42 for optical paths was formed (refer Fig.7 (a)).
[0210]
(19) Next, a photosensitizing agent obtained by acrylated 50% of an epoxy group of a cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) dissolved in diethylene glycol dimethyl ether (DMDG) to a concentration of 60% by weight. 46.67 parts by weight of oligomer (molecular weight: 4000), 80% by weight of bisphenol A type epoxy resin (trade name: Epicoat 1001 manufactured by Yuka Shell Co., Ltd.) dissolved in methyl ethyl ketone, 15.0 parts by weight, imidazole curing agent (Shikoku Kasei Co., Ltd., trade name: 2E4MZ-CN) 1.6 parts by weight, photofunctional monomer bifunctional acrylic monomer (Nippon Kayaku Co., Ltd., trade name: R604) 4.5 parts by weight, also polyvalent acrylic monomer ( Kyoei Chemical Co., Ltd., trade name: DPE6A) 1.5 parts by weight, dispersion antifoaming agent (San Nopco, S-65) Take 1 part by weight in a container, stir and mix to prepare a mixed composition. 2.0 parts by weight of benzophenone (manufactured by Kanto Chemical Co., Inc.) as a photopolymerization initiator for this mixed composition, as a photosensitizer By adding 0.2 part by weight of Michler's ketone (manufactured by Kanto Chemical Co., Inc.), a solder resist composition having a viscosity adjusted to 2.0 Pa · s at 25 ° C. was obtained.
The viscosity is measured with a B-type viscometer (DVL-B type, manufactured by Tokyo Keiki Co., Ltd.) for 60 minutes.^{- 1}(Rpm), rotor No. 4, 6 min^{- 1}(Rpm), rotor No. 3 according.
[0211]
(20) Next, the solder resist composition is applied in a thickness of 30 μm on both surfaces of the substrate on which the interlayer resin insulation layer 22 and the conductor circuit 25 (including the via hole 27) are formed, and is performed at 70 ° C. for 20 minutes. A drying process was performed at 70 ° C. for 30 minutes to form a solder resist composition layer 34 ′ (see FIG. 7B).
[0212]
(21) Next, a 5 mm-thick photomask on which patterns of optical path openings and solder bump formation openings (IC chip mounting openings and optical element mounting openings) are drawn is used as a solder resist composition on the IC chip mounting side. 1000 mJ / cm in close contact with the layer 34 '²Were exposed to UV light and developed with DMTG solution to form openings. Further, the solder resist 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. A solder resist layer 34 having a formation opening 35 and a thickness of 20 μm was formed.
In addition, a photomask on which a pattern of solder bump formation openings (multilayer printed wiring board connection openings) is drawn is brought into close contact with the other solder resist composition layer, and exposure is performed under the same conditions as the exposure and development conditions described above. By performing development processing, solder bump forming openings 35 for connection to the multilayer printed wiring board were formed (see FIG. 8A).
[0213]
(22) Next, a resin composition similar to the resin composition containing the epoxy resin filled in the step (18) is filled into the optical path opening formed in the step (21) using a squeegee. After drying, the surface layer was flattened by buffing. Furthermore, the hardening process was performed and the resin layer 42 for optical paths was formed.
The optical path resin layer formed in this step and the step (18) has a transmittance of 85% and a refractive index of 1.60.
[0214]
(23) Next, the substrate on which the solder resist layer 34 is formed is nickel chloride (2.3 × 10^-1mol / l), sodium hypophosphite (2.8 × 10^-1mol / l), sodium citrate (1.6 × 10^-1A nickel plating layer having a thickness of 5 μm was formed in the solder bump forming opening 35 and the optical element opening 31 by immersing in an electroless nickel plating solution containing 0.5 mol / l) of pH = 4.5. Further, the substrate was made of potassium gold cyanide (7.6 × 10 6^-3mol / l), ammonium chloride (1.9 × 10^-1mol / l), sodium citrate (1.2 × 10^-1mol / l), sodium hypophosphite (1.7 × 10^-1Molle-l) was immersed in an electroless gold plating solution at 80 ° C. for 7.5 minutes to form a 0.03 μm-thick gold plating layer on the nickel plating layer.
[0215]
(24) Next, a solder paste is printed in the solder bump forming opening 35 formed in the solder resist layer 34, and the light receiving element 38 and the light emitting element 39 are respectively applied to the solder paste printed in the optical element mounting opening. The light receiving portion 38a and the light emitting portion 39a are attached while being aligned and reflowed at 200 ° C., so that the light receiving device 38 and the light emitting device 39 are mounted via solder, as well as an IC chip mounting opening and a multilayer printed wiring board. Solder bumps 37 were formed in the mounting openings to form an IC chip mounting substrate (see FIG. 8B).
The light receiving element 38 was made of InGaAs, and the light emitting element 39 was made of InGaAsP.
[0216]
B. Fabrication of multilayer printed wiring board
B-1. Preparation of resin film for interlayer resin insulation layer
The resin film for interlayer resin insulation layers was produced using the method similar to the method used by A-1.
B-2. Preparation of resin composition for filling through-hole
A resin composition for filling a through hole was produced using the same method as used in A-2.
[0217]
B-3. Manufacture of multilayer printed wiring boards
(1) A copper-clad laminate in which 18 μm copper foil 8 is laminated on both surfaces of an insulating substrate 1 made of glass epoxy resin or BT resin having a thickness of 0.6 mm was used as a starting material (see FIG. 9A). ). First, the copper-clad laminate was drilled, subjected to electroless plating, and etched into a pattern to form conductor circuits 4 and through holes 9 on both sides of the substrate 1 (FIG. 9B). reference).
[0218]
(2) The substrate on which the through hole 9 and the conductor circuit 4 are formed is washed with water, dried, and then sprayed with an etching solution (MEC Etch Bond, manufactured by MEC Co., Ltd.) on the surface of the conductor circuit 4 including the through hole 9. A roughened surface (not shown) was formed.
[0219]
(3) After preparing the resin filler described in the above B-2, within 24 hours after preparation by the following method, the conductor circuit non-formed part on the through hole 9 and the substrate 1 and the outer edge part of the conductor circuit 4 And a layer of resin filler 10 '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, The layer of resin filler 10 'was formed by drying on the conditions for 20 minutes (refer FIG.9 (c)).
[0220]
(4) The surface of the conductor circuit 4 or the land surface of the through hole 9 is polished on one side of the substrate after the processing of (3) by belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku). Polishing was performed so that the resin filler 10 '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 10 was formed.
[0221]
In this way, the surface layer portion of the resin filler 10 and the surface of the conductor circuit 4 formed in the through hole 9 and the conductor circuit non-forming portion are flattened, and the resin filler 10 and the side surface of the conductor circuit 4 are roughened. Thus, an insulating substrate was obtained in which the inner wall surface of the through hole 9 and the resin filler 10 were firmly adhered via a roughened surface (see FIG. 9D). By this step, the surface of the resin filler layer 10 and the surface of the conductor circuit 4 are flush with each other.
[0222]
(5) After washing the substrate with water, acid degreasing, soft etching, and then spraying the etchant on both sides of the substrate by spraying to etch the surface of the conductor circuit 4 and the land surface of the through hole 9, A roughened surface (not shown) was formed on the entire surface of the conductor circuit 4. As an etchant, MEC Etch Bond manufactured by MEC was used.
[0223]
(6) Next, a resin film for an interlayer resin insulation layer that is slightly larger than the substrate prepared in B-1 above is placed on the substrate, and temporarily mounted under the conditions of pressure 0.4 MPa, temperature 80 ° C., and pressure bonding time 10 seconds. After crimping and cutting, an interlayer resin insulating layer 2 was further formed by sticking using a vacuum laminator apparatus by the following method (see FIG. 10A). That is, a resin film for an interlayer resin insulation layer was subjected to main pressure bonding on a substrate under conditions of a degree of vacuum of 65 Pa, a pressure of 0.4 MPa, a temperature of 80, and a time of 60 seconds, and then thermally cured at 170 ° C. for 30 minutes.
[0224]
(7) Next, CO 2 having a wavelength of 10.4 μm is passed through a mask in which a through hole having a thickness of 1.2 mm is formed on the interlayer resin insulation layer 2.₂With a gas laser, a via hole opening with a diameter of 80 μm in the interlayer resin insulation layer 2 under the conditions of a beam diameter of 4.0 mm, a top hat mode, a pulse width of 8.0 μsec, a mask through hole diameter of 1.0 mm, and one shot. 6 was formed (see FIG. 10B).
[0225]
(8) The substrate on which the via-hole opening 6 has been formed is immersed 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 interlayer resin insulation layer 2. Thus, a roughened surface (not shown) was formed on the surface including the inner wall surface of the via hole opening 6.
[0226]
(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 nucleus is formed on the surface of the interlayer resin insulating layer 2 (including the inner wall surface of the via-hole opening 6) by applying a palladium catalyst to the surface of the substrate that has been subjected to roughening surface treatment (roughening depth 3 μm). Was attached (not shown). That is, the substrate is made of palladium chloride (PdCl₂) And stannous chloride (SnCl)₂The catalyst was imparted by immersing it in a catalyst solution containing) and depositing palladium metal.
[0227]
(10) Next, the substrate is immersed in an electroless copper plating aqueous solution and electroless with a thickness of 0.6 to 3.0 μm on the surface of the interlayer resin insulating layer 2 (including the inner wall surface of the via hole opening 6). A copper plating film 12 was formed (see FIG. 10C).
The electroless plating aqueous solution and the electroless plating conditions used are the same as in (10) of the manufacturing process of the IC chip mounting substrate.
[0228]
(11) The substrate on which the electroless plating film 12 is formed is washed with water, and then electroplating is performed to form an electrolytic copper plating film 13 having a thickness of 20 μm on the entire electroless plating film 12 (FIG. 11A). reference).
The electrolytic plating aqueous solution and the electrolytic plating conditions used are the same as in (12) of the manufacturing process of the IC chip mounting substrate.
[0229]
(12) Next, a commercially available photosensitive dry film is attached to the substrate on which the electrolytic copper plating film 13 is formed, and a mask is placed thereon, and 100 mJ / cm.²Then, an etching resist 3 was formed by developing with a 0.8% aqueous sodium carbonate solution (see FIG. 11B).
[0230]
(13) Next, the electrolytic copper plating film and the electroless plating film under the etching resist non-formation portion are dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide, and then the etching resist is 5% NaOH. The conductive circuit 7 (including the via hole 5) composed of the electroless copper plating film 12 and the electrolytic copper plating film 13 was formed by peeling and removing with a solution (see FIG. 11C).
Further, a roughened surface (not shown) was formed on the surface of the conductor circuit 5 (including the via hole 7) using an etching solution (MEC etch bond).
[0231]
(14) Next, optical waveguides 18 (18a, 18b) having optical path conversion mirrors 19 (19a, 19b) were formed at predetermined positions on the surface of interlayer resin insulation layer 2 using the following method (FIG. 12 ( a)).
That is, a film-like optical waveguide (width 25 μm, thickness 25 μm) made of PMMA in which a 45 ° optical path conversion mirror 19 is formed in advance using a diamond saw with a V-shaped 90 ° tip at one end is used as an optical path. The side surfaces of the other end on the conversion mirror non-forming side and the side surface of the interlayer resin insulating layer were attached so as to be aligned.
In addition, the optical waveguide is attached by applying an adhesive made of a thermosetting resin to a thickness of 10 μm on the adhesive surface of the optical waveguide with the interlayer resin insulating layer, and curing at 60 ° C. for 1 hour after the pressure bonding. Was done.
In this embodiment, curing is performed under the condition of 60 ° C./1 hour, but step curing may be performed depending on circumstances. This is because stress is hardly generated by the optical waveguide at the time of pasting.
[0232]
(15) Next, a solder resist composition is prepared in the same manner as in the manufacturing process of the IC chip mounting substrate (19), and the solder resist composition is applied to both sides of the substrate in a thickness of 35 μm. Then, a drying process was performed under the conditions of 70 ° C. for 20 minutes and 70 ° C. for 30 minutes to form a solder resist composition layer 14 ′ (see FIG. 12B).
[0233]
(16) Next, a 5 mm thick photomask on which a pattern of solder bump forming openings (openings for connecting to an IC chip mounting substrate) and optical path openings is drawn on one side of the substrate is used as a solder resist layer. 1000mJ / cm with close contact²Were exposed to ultraviolet rays and developed with a DMTG solution to form openings.
Further, the solder resist 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 14 having an optical path opening 11 (11a, 11b) and a thickness of 20 μm was formed (see FIG. 13A).
[0234]
(17) Next, in the same manner as the step (22) of the manufacturing process of the IC chip mounting substrate, the resin composition containing the epoxy resin is filled and cured, and the optical path resin layer is formed in the optical path opening. 8 was formed. Further, a nickel plating layer and a gold plating layer were formed in the same manner as the step (23) of the manufacturing process of the IC chip mounting substrate, and the solder pad 16 was obtained.
[0235]
(18) Next, a solder paste is printed in the solder bump forming opening 15 formed in the solder resist layer 14 and reflowed at 200 ° C. to form the solder bump 17 in the solder bump forming opening 15, and the multilayer printed wiring It was set as the board (refer FIG.13 (b)).
[0236]
C. Manufacture of IC-mounted optical communication devices
First, an IC chip was mounted on the IC chip mounting substrate manufactured through the process A, and then resin sealing was performed to obtain an IC chip mounting substrate.
Next, this IC chip mounting substrate and the multilayer printed wiring board manufactured through the above step B are placed opposite to each other at a predetermined position and reflowed at 200 ° C. to connect the solder bumps of both substrates to each other. Part was formed.
[0237]
Next, a sealing resin composition is formed by filling a sealing resin composition between the multilayer printed wiring board and the IC chip mounting substrate connected via the solder connection portion, and then performing a curing process. Thus, an optical communication device was obtained (see FIG. 1).
In addition, as the resin composition for sealing, the resin composition containing an epoxy resin was used.
The formed sealing resin layer had a transmittance of 85% and a refractive index of 1.60.
[0238]
(Example 2)
An optical path resin layer having a transmittance of 80% and a refractive index of 1.58 using a resin composition containing an olefin resin when forming an optical path resin layer on an IC chip mounting substrate and a multilayer printed wiring board When a sealing resin layer is formed using a resin composition containing an olefin resin as a sealing resin composition, the sealing resin has a transmittance of 88% and a refractive index of 1.58 An optical communication device was produced in the same manner as in Example 1 except that the layer was formed.
[0239]
(Example 3)
After performing the step (23) of the manufacturing process of the IC chip mounting substrate of Example 1, the microlens was attached to the end of the optical path resin layer on the side connected to the multilayer printed wiring board using the following method. An optical communication device was manufactured in the same manner as in Example 1 except for the arrangement.
That is, a microlens was formed by dropping a resin composition containing an epoxy resin onto an end of the optical path resin layer using a dispenser and then performing a curing treatment. The microlens formed here has a transmittance of 92% and a refractive index of 1.62.
[0240]
Example 4
In Example 2, after forming the optical path resin layer by performing the same process as the process (23) of the manufacturing process of the IC chip mounting substrate of Example 1, the multilayer printed wiring board of the optical path resin layer A device for optical communication was manufactured in the same manner as in Example 2 except that a microlens was disposed at the end on the side to be connected to the surface using the following method.
That is, a microlens was formed by dropping a resin composition containing an epoxy resin onto an end of the optical path resin layer using a dispenser and then performing a curing treatment. The microlens formed here has a transmittance of 92% and a refractive index of 1.62.
[0241]
(Example 5)
After performing the step (23) of the manufacturing process of the IC chip mounting substrate of Example 1, the microlens was attached to the end of the optical path resin layer on the side connected to the multilayer printed wiring board using the following method. A device for optical communication was manufactured in the same manner as in Example 1 except that a resin composition containing an acrylic resin was used when the sealing resin layer was disposed.
That is, a microlens was formed by dropping a resin composition containing an epoxy resin onto an end of the optical path resin layer using a dispenser and then performing a curing treatment. The microlens formed here has a transmittance of 85% and a refractive index of 1.60.
The sealing resin layer formed in this example has a transmittance of 85% and a refractive index of 1.50.
[0242]
(Example 6)
In Example 2, after forming the optical path resin layer by performing the same process as the process (23) of the method for manufacturing the IC chip mounting substrate of Example 1, the multilayer printed wiring board of the optical path resin layer Example 1 except that a microlens is disposed at the end on the side to be connected to the surface using the following method, and a resin composition containing an acrylic resin is used when forming the sealing resin layer. In the same manner, an optical communication device was manufactured.
That is, a microlens was formed by dropping a resin composition containing an epoxy resin onto an end of the optical path resin layer using a dispenser and then performing a curing treatment. The microlens formed here has a transmittance of 92% and a refractive index of 1.62.
The sealing resin layer formed in this example has a transmittance of 85% and a refractive index of 1.50.
[0243]
(Example 7)
In the step (14) of the manufacturing process of the multilayer printed wiring board of Example 1, solder bumps are formed so as to cover the entire outermost interlayer resin insulation layer by using the following method when the optical waveguide is formed. An optical waveguide that is superior to the aperture for the optical path and the optical path conversion mirror is formed, and optical communication is performed in the same manner as in Example 1 except that the solder resist layer is not formed on the outermost layer on the side where such an optical waveguide is formed. The device was manufactured.
[0244]
A method of forming an optical waveguide that covers the entire interlayer resin insulation layer will be described. First, a lower clad forming PMMA is applied and formed at a predetermined position on the outermost interlayer resin insulation layer, and this is heated and cured to form a lower clad. Thereafter, a core is formed on the lower clad. A core layer was formed by coating PMMA for coating and heating and curing it. Thereafter, a resist was applied to the surface of the core layer, a resist pattern was formed by photolithography, and the core was formed on the lower clad by patterning into the shape of the core by reactive ion etching.
Subsequently, a 45 ° optical path conversion mirror was formed by machining on one end of the lower clad and the core.
[0245]
Next, PMMA for forming an upper clad was applied over the entire interlayer resin insulation layer so as to cover the lower clad and the core, and the upper clad was formed over the entire interlayer resin insulation layer by heating and curing this.
The lower clad forming PMMA and the upper clad forming PMMA have the same composition.
In addition, an optical waveguide will be formed in the whole on the outermost interlayer resin insulation layer by passing through such a process.
Thereafter, openings for forming solder bumps were formed in the optical waveguide by laser processing.
[0246]
(Example 8)
Mount the optical waveguide formed on the multilayer printed wiring board on the optical resin and the IC chip mounting board on the outermost interlayer resin insulation layer opposite the IC chip mounting board and the opposite side of the board An optical communication device was manufactured in the same manner as in Example 1 except that an optical path for transmitting an optical signal was formed so that an optical signal could be transmitted to and from the optical element.
The multilayer printed wiring board having the above-described configuration was formed through the following steps (1) to (7).
[0247]
That is, (1) First, B-3. In the same manner as in the production of the multilayer printed wiring board (1) to (8), an interlayer resin insulation layer having conductor circuits and via hole openings was formed on both surfaces of the substrate.
(2) Next, using a drill having a diameter of 300 μm, an optical path through hole penetrating the substrate and the interlayer resin insulation layer was formed, and further, a desmear treatment was applied to the wall surface of the optical path through hole.
[0248]
(3) Next, a catalyst is applied to the wall surface of the through hole for an optical path and the surface of the interlayer resin insulating layer by the same method as used in the step (9) of B-3 of Example 1, Furthermore, the substrate is immersed in an electroless copper plating aqueous solution similar to the electroless plating solution used in the process (10) of B-3 of Example 1, and the surface of the interlayer resin insulation layer (inside the via hole opening) Thin film conductor layer (electroless copper plating film) was formed on the wall surface of the through hole for optical path).
[0249]
(4) Next, A-3. A plating resist was formed at a predetermined position on the thin film conductor layer by the same method as used in the step (11) of manufacturing the IC chip mounting substrate. Furthermore, the electrolytic copper plating film was formed in the plating resist non-formation part by the method similar to the method used at the process of A-3 (12).
[0250]
(5) Next, the plating resist and the thin-film conductor layer under the plating resist are removed by the same method as used in the step (13) of A-3. Formed. Furthermore, the surface of the said conductor circuit was made into the roughening surface by performing an oxidation reduction process.
[0251]
(6) Next, using a squeegee, the resin composition containing an epoxy resin is filled into the through hole for an optical path in which the conductor layer is formed, and after drying, the surface layer is flattened by buffing and further cured. Was applied to form an optical path resin layer.
[0252]
(7) Next, using the same method as the process (14) of B-3 in Example 1, the interlayer resin insulation of the outermost layer on the opposite side across the substrate and the side facing the IC chip mounting substrate An optical waveguide superior to the optical path conversion mirror was formed at a predetermined position on the layer.
Then, the multilayer printed wiring board was completed by performing the process similar to the process of (15)-(18) of B-3. When the optical path opening was formed in this step, the optical path opening was formed so as to communicate with the optical path through hole formed in the step (2).
[0253]
For the IC-mounted optical communication devices of Examples 1 to 8 thus obtained, an optical fiber is attached to the exposed surface from the side surface of the multilayer printed wiring board of the optical waveguide facing the light receiving element, and the light receiving element is substituted. The detector is attached, and then the optical signal is sent through the optical fiber. When the optical signal is detected by the detector, the desired optical signal can be detected. It was revealed that the device has sufficiently satisfactory performance as an optical communication device.
[0254]
Further, when the waveguide loss between the light emitting element mounted on the IC chip mounting substrate and the optical waveguide formed on the multilayer printed wiring board facing the light emitting element was measured by the following method, it was 0.3 dB. / Cm or less, and it has become clear that an optical signal can be sufficiently transmitted.
The waveguide loss is measured by attaching an optical fiber to the end of the light receiving optical waveguide and attaching a power meter to the end of the optical signal transmission optical path on the light receiving element side through the optical fiber. An optical signal having a measurement wavelength of 850 nm was transmitted from the optical fiber attached to the optical fiber, and the optical signal transmitted through the light receiving optical waveguide and the optical signal transmitting optical path was detected by a power meter.
[0255]
Furthermore, in the optical communication devices obtained in Examples 1 to 8, there was almost no positional deviation from the design of the optical element (light receiving element and light emitting element) and the optical waveguide.
[0256]
【The invention's effect】
As described above, an optical communication device according to the present invention includes an IC chip mounting substrate on which a light receiving element and a light emitting element are mounted at predetermined positions, and a multilayer printed wiring board on which an optical waveguide is formed at predetermined positions. Since it is configured, the connection loss between the mounted optical components is low, and the connection reliability is excellent as an optical communication device.
[0257]
Further, in the optical communication device of the present invention, when a sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board, the air is interposed between the optical element and the optical waveguide. Therefore, the dust or foreign matter floating in the air does not enter, and the transmission of the optical signal is not hindered by the dust or foreign matter, so that the reliability as an optical communication device is improved.
Furthermore, when a sealing resin layer is formed, the sealing resin layer can serve to relieve stress generated between the IC chip mounting substrate and the multilayer printed wiring board, Further, since the positional deviation of the optical element and the optical waveguide is less likely to occur, the reliability as an optical communication device is more excellent.
[0258]
In the method for manufacturing an optical communication device of the present invention, an IC chip mounting substrate and a multilayer printed wiring board are arranged and fixed at predetermined positions, and then a sealing resin layer is formed between them. It is possible to suitably manufacture an optical communication device that is suspended in the air between the optical waveguide and that dust and foreign matters do not enter and the transmission of optical signals is not hindered.
[0259]
Further, by forming a sealing resin layer between the IC chip mounting substrate and the multilayer printed wiring board, in the obtained optical communication device, the sealing resin layer is the above IC chip mounting substrate and the above It can play the role of relieving the stress generated due to the difference in thermal expansion coefficient with the multilayer printed wiring board, and the formation of the sealing resin layer can shift the position of the optical element and optical waveguide. Less likely to occur.
Therefore, in the manufacturing method of the present invention, an optical communication device having excellent reliability can be preferably manufactured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an embodiment of an optical communication device of the present invention.
FIG. 2 is a cross-sectional view schematically showing another embodiment of the device for optical communication of the present invention.
FIG. 3 is a cross-sectional view schematically showing still another embodiment of the optical communication device of the present invention.
FIG. 4 is a cross-sectional view schematically showing a part of a process for manufacturing an IC chip mounting substrate constituting the optical communication device of the present invention.
FIG. 5 is a cross-sectional view schematically showing a part of a process of manufacturing an IC chip mounting substrate constituting the optical communication device of the present invention.
FIG. 6 is a cross-sectional view schematically showing a part of a process of manufacturing an IC chip mounting substrate constituting the optical communication device of the present invention.
FIG. 7 is a cross-sectional view schematically showing a part of a process of manufacturing an IC chip mounting substrate constituting the optical communication device of the present invention.
FIG. 8 is a cross-sectional view schematically showing a part of a process of manufacturing an IC chip mounting substrate constituting the optical communication device of the present invention.
FIG. 9 is a cross-sectional view schematically showing a part of a process for manufacturing a multilayer printed wiring board constituting the device for optical communication of the present invention.
FIG. 10 is a cross-sectional view schematically showing part of a process for manufacturing the multilayer printed wiring board constituting the device for optical communication of the present invention.
FIG. 11 is a cross-sectional view schematically showing part of a process for manufacturing the multilayer printed wiring board constituting the device for optical communication of the present invention.
FIG. 12 is a cross-sectional view schematically showing a part of a process for manufacturing a multilayer printed wiring board constituting the device for optical communication of the present invention.
FIG. 13 is a cross-sectional view schematically showing part of a process for manufacturing the multilayer printed wiring board constituting the device for optical communication of the present invention.
FIG. 14 is a cross-sectional view schematically showing an embodiment of an optical communication device of the present invention.
[Explanation of symbols]
100, 200, 300 multilayer printed wiring board
101, 201, 301 substrate
102, 202, 302 Interlayer resin insulation layer
104, 204, 304 Conductor circuit
107, 207, 307 Via hole
109, 209, 309 Through hole
111, 211 Opening for optical path
114, 214, 314 Solder resist layer
118, 218, 318 Optical waveguide
119, 219, 319 Optical path conversion mirror
120, 220, 320 IC chip mounting substrate
121, 221 and 321 substrates
122, 222, 322 Interlayer resin insulation layer
124, 224, 324 Conductor circuit
127, 227, 327 Via hole
129, 229, 329 Through hole
134, 234, 334 Solder resist layer
137, 237, 337 Solder connection
138, 238, 338 Light receiving element
139, 239, 339 Light emitting element
140 IC chip
141, 241, 341, 351 Optical path for optical signal transmission
142, 242, 342, 352 Optical path resin layer
145, 245, 345, 355 Conductor layer
150, 250, 350 Optical communication devices
160, 260, 360 Sealing resin layer

Claims (7)

An optical path for optical signal transmission is formed, and an IC chip mounting substrate having an optical element mounted on one surface;
An optical communication device comprising at least a multilayer printed wiring board on which an optical waveguide is formed,
The optical signal transmission optical path is formed so as to penetrate the IC chip mounting substrate, and an optical path resin layer is formed therein,
A microlens is disposed at least at the end of the optical signal transmission optical path on the multilayer printed wiring board side,
A sealing resin layer is formed between the IC chip mounting substrate and the multilayer printed wiring board,
The refractive index of the microlens is larger than the refractive index of the sealing resin layer,
An optical communication device, wherein the optical waveguide and the optical element are configured to transmit an optical signal via the optical signal transmission optical path. The multilayer printed wiring board has an optical path opening in which an optical path resin layer is formed,
2. The optical communication device according to claim 1, wherein a microlens having a refractive index larger than a refractive index of the sealing resin layer is disposed at an end of the optical path opening on the sealing resin layer side. The thickness of the optical path for transmitting an optical signal is the same as the thickness of the opening for the optical path, and
3. The light according to claim 2, wherein the refractive index of the microlens disposed at the end of the optical signal transmission optical path is the same as the refractive index of the microlens disposed at the end of the optical path opening. Communication device. The device for optical communication according to any one of claims 1 to 3, wherein the sealing resin layer has a transmittance of communication wavelength light of 70% or more. The device for optical communication according to claim 1, wherein particles are contained in the sealing resin layer. The optical element, the optical communication device according to any one of claims 1 to 5 which is a light receiving element and / or the light emitting device. After the optical path for optical signal transmission is formed and the IC chip mounting substrate on which the optical element is mounted on one surface and the multilayer printed wiring board on which at least the optical waveguide is formed are separately manufactured,
Between the optical element of the IC chip mounting substrate and the optical waveguide of the multilayer printed wiring board, both are arranged and fixed at a position where an optical signal can be transmitted,
Furthermore, in the after pouring a sealing resin composition between the IC chip mounting board and the multilayer printed wiring board, method of manufacturing the optical communication device for forming a layer sealing resin by subjecting to a curing treatment There,
When forming the optical signal transmission optical path, the optical chip transmission board is formed so as to penetrate through the IC chip mounting substrate, and an optical path resin layer is formed therein, and the multilayer print of the optical signal transmission optical path is further formed. A method for manufacturing an optical communication device, comprising: a microlens having a refractive index larger than that of the sealing resin layer at an end portion on a side facing a wiring board.

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