JP4540275B2 - IC chip mounting substrate and manufacturing method of IC chip mounting substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an IC chip mounting substrate.
[0002]
[Prior art]
In recent years, attention has been focused on optical fibers mainly in the communication field. Particularly in the IT (information technology) field, communication technology using optical fibers is required for the development of 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) no induction, and (5) resource saving. Compared with communication systems using conventional metallic cables, the number of repeaters can be greatly reduced, making construction and maintenance easier, and making communication systems more economical and more reliable. Can be planned.
[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 element such as a light-receiving element or a light-emitting element that processes an optical signal is separately mounted, and an electrical wiring or an optical waveguide is connected to these, Signal transmission and signal processing were performed.
In addition, an optical element such as a light receiving element is built in a package substrate on which an IC chip is mounted, and optical communication of a terminal device is performed using the package substrate (hereinafter also referred to as an optical element built-in package substrate) containing the optical element. It has also been proposed to do.
[0006]
[Problems to be solved by the invention]
In such a conventional terminal device, when a package substrate on which an IC chip is mounted and an optical element such as a light receiving element or a light emitting element for processing an optical signal are separately mounted, the device itself becomes large, It was difficult to reduce the size.
In addition, when an IC chip mounting substrate with an optical element built-in and an IC chip mounted thereon is used, the problem that the device itself becomes large is solved, but there are the following disadvantages.
[0007]
That is, in the package substrate with a built-in optical element, since the optical element is completely built in the substrate, fine adjustment of alignment can be performed when connecting to an external optical element (such as an optical fiber or an optical waveguide). It is difficult, and since the optical element is built in when the package substrate is manufactured, the optical element is liable to be displaced. This is because heat treatment or the like needs to be performed in the manufacturing process of the package substrate, and when the optical element is built in the resin layer, it is considered that the optical element is displaced during the heat treatment.
Thus, when a positional shift occurs in the built-in optical element, the connection loss when connecting to an external optical element is large, leading to a decrease in connection reliability in optical communication.
In addition, in the package substrate with a built-in optical element, if any of the built-in optical elements is inconvenient, only the optical element cannot be replaced, and the package substrate with a built-in optical element itself becomes a defective product. It was disadvantageous.
[0008]
The present invention has been made in view of the above-described problems, and can achieve miniaturization of a terminal device, can easily replace an optical element, and achieve optical communication excellent in connection reliability. An object of the present invention is to provide an IC chip mounting substrate that can be used.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the IC chip mounting substrate of the present invention has a conductive circuit and an interlayer resin insulation layer formed on both sides of the substrate, a solder resist layer is formed on the outermost layer, and an optical element is mounted. An IC chip mounting substrate, wherein an optical waveguide is formed inside the IC chip mounting substrate, and an optical signal transmission optical path for connecting the optical element and the optical waveguide is formed. Features.
[0010]
In the IC chip mounting substrate of the present invention, the optical waveguide is preferably an organic optical waveguide.
[0011]
In the IC chip mounting substrate of the present invention, the optical signal transmission optical path may be constituted by a gap, a resin composition and a gap, or a resin composition. desirable.
[0012]
In the IC chip mounting substrate of the present invention, the optical signal transmission optical path is constituted by a gap and a surrounding conductor layer, or is constituted by a resin composition and a gap and a surrounding conductor layer. It is also desirable that it is constituted by a resin composition and a surrounding conductor layer.
[0013]
In the IC chip mounting substrate, the mounting position of the optical element is preferably the surface of the IC chip mounting substrate, and the optical element is preferably a light receiving element and / or a light emitting element.
Moreover, it is desirable that electronic components are mounted on the surface of the IC chip mounting substrate.
[0014]
In the IC chip mounting substrate, it is desirable that a microlens is formed in an end portion of the optical signal transmission optical path or in the optical signal transmission optical path. The diameter is desirably 100 to 500 μm.
[0015]
In the IC chip mounting substrate, the conductor circuits sandwiching the substrate are connected via through holes, and the conductor circuits sandwiching the interlayer resin insulation layer are connected via via holes. desirable.
[0016]
The method for manufacturing an IC chip mounting substrate of the first aspect of the present invention is characterized in that a substrate, an optical waveguide, and a laminate manufactured through at least the following steps (a) to (c) are laminated in this order. And
(A) a conductor circuit laminate forming step in which a conductor circuit and an interlayer resin insulating layer are sequentially laminated on a base material layer to form a conductor circuit laminate;
(B) an opening forming step for forming an opening to be an optical path for optical signal transmission in the conductor circuit laminate, and
(C) A solder resist layer forming step of forming a solder resist layer having an opening communicating with the opening formed in the step (b) on one side of the conductor circuit laminate.
[0017]
The manufacturing method of the IC chip mounting substrate of the second aspect of the present invention,
(A) an optical waveguide forming step of forming an optical waveguide on a substrate on which a conductor circuit is formed;
(B) A multilayer wiring board manufacturing process in which an interlayer resin insulating layer and a conductor circuit are sequentially laminated on the substrate on which the optical waveguide is formed, to form a multilayer wiring board;
(C) an opening forming step of forming an opening serving as an optical path for optical signal transmission in the multilayer wiring board;
(D) a solder resist layer forming step of forming a solder resist layer having an opening communicating with the opening formed in the step (c) on one side of the multilayer wiring board;
It is characterized by including.
[0018]
It is desirable that the method for manufacturing an IC chip mounting substrate of the first or second aspect of the invention includes a roughened surface forming step in which the wall surface of the opening serving as the optical path for transmitting an optical signal is roughened. Moreover, it is preferable that the manufacturing method of the IC chip mounting substrate according to the first or second aspect of the present invention includes a conductor layer forming step of forming a conductor layer on the wall surface of the opening serving as the optical path for optical signal transmission.
[0019]
Moreover, the manufacturing method of the substrate for mounting an IC chip according to the first or second aspect of the invention may include a resin composition filling step of filling an uncured resin composition into the opening that becomes the optical path for transmitting an optical signal. desirable.
In addition, the first or second method for manufacturing an IC chip mounting substrate according to the present invention preferably includes a microlens forming step of forming a microlens at an end portion of the opening serving as the optical path for transmitting an optical signal.
In addition, it is desirable that the method for manufacturing an IC chip mounting substrate according to the first or second aspect of the present invention includes a microlens forming step of forming a microlens in the opening that becomes the optical path for transmitting an optical signal.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the IC chip mounting substrate of the present invention will be described.
The IC chip mounting substrate of the present invention is an IC chip mounting substrate in which a conductor circuit and an interlayer resin insulating layer are laminated on both surfaces of the substrate, a solder resist layer is formed on the outermost layer, and an optical element is mounted. Because
An optical waveguide is formed inside the IC chip mounting substrate,
An optical path for transmitting an optical signal that connects the optical element and the optical waveguide is formed.
[0021]
The IC chip mounting substrate of the present invention has an optical waveguide formed therein and an optical signal transmission optical path for connecting the optical element and the optical waveguide. The input / output signal of the optical element can be transmitted through the transmission optical path. Further, when the IC chip is mounted on the substrate, the distance between the IC chip and the optical element is short, and the reliability of electric signal transmission is excellent.
In addition, in the IC chip mounting substrate of the present invention on which the IC chip is mounted, electronic components and optical elements necessary for optical communication can be integrated, and can be connected to external elements on the side surface of the substrate. The IC chip mounting substrate can be made thinner and smaller.
[0022]
If the optical element is surface-mounted, after forming the conductor circuit and interlayer resin insulation layer of the IC chip mounting substrate, the conductor circuit and interlayer resin insulation layer are formed to mount the optical element. At the time of the heat treatment, the optical element is not mounted, and a positional shift that may occur at the time of the heat treatment does not occur.
In the case where the optical element is surface-mounted, if a problem occurs in one optical element, only the optical element needs to be replaced, which is economically advantageous.
[0023]
Furthermore, in the IC chip mounting substrate of the present invention, since the optical waveguide is formed inside the IC chip mounting substrate, the adhesion of foreign matters to the wall surface of the optical waveguide is prevented, and the irregular reflection of light is reduced. Therefore, the transmission property of the optical signal can be improved.
[0024]
In the present invention, the optical waveguide is formed inside the IC chip mounting substrate.
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 is desirable. This is because it has excellent adhesion to the substrate and the interlayer resin insulation layer and can be easily formed and processed.
[0025]
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 resin composite of a thermosetting resin and a thermoplastic resin, a composite of a photosensitive resin and a thermoplastic resin, and the like.
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.
[0026]
In addition to the resin component, the optical waveguide 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 waveguide and the substrate, the interlayer resin insulating layer, the solder resist layer, or the like.
[0027]
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.
[0028]
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.
[0029]
Examples of the inorganic particles include aluminum compounds such as alumina and aluminum hydroxide, calcium compounds such as calcium carbonate and calcium hydroxide, potassium compounds such as potassium carbonate, magnesium compounds such as magnesia, dolomite, and basic magnesium carbonate. And silicon compounds such as silica and zeolite, and titanium compounds such as titania.
Moreover, what consists of phosphorus or a phosphorus compound can also be used as said inorganic particle.
[0030]
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.
[0031]
The shape of the particles such as the resin particles is not particularly limited, and examples thereof include a spherical shape, an elliptical spherical shape, a crushed shape, and a polyhedral shape. The particle size of the particles is preferably shorter than the communication wavelength. This is because if the particle size is longer than the communication wavelength, transmission of the optical signal may be hindered.
[0032]
The average particle size of the particles is preferably 0.1 to 20 μm, and particularly preferably 0.5 to 10 μm. If it is the range of this particle size, you may contain the particle | grains of 2 or more types of different particle sizes. That is, the case of containing particles having an average particle diameter of 0.5 to 4 μm and particles having an average particle diameter of 1 to 10 μm. In the present specification, the particle diameter refers to the length of the longest part of the particle.
[0033]
The blending amount of the particles contained in the optical waveguide is preferably 10 to 80% by weight, and more preferably 20 to 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.
[0034]
The shape of the optical waveguide is not particularly limited, but a sheet shape is desirable because it is easy to form.
[0035]
The thickness of the optical waveguide is desirably 5 to 100 μm, and more desirably the same thickness as the conductor circuit. This is because when the optical waveguide is formed, the surface of the optical waveguide and the surface of the conductor circuit are flush with each other.
The width of the optical waveguide is preferably 5 to 100 μm. If the width is less than 5 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 IC chip mounting substrate. Because there is.
Further, in the above IC chip mounting substrate, when the light receiving element and the light emitting element are mounted as the optical elements, the optical waveguide formed at the position facing the light receiving element and the position facing the light emitting element are formed. The optical waveguide is preferably made of the same material. This is because the thermal expansion coefficients are easily matched and can be easily formed and processed.
[0036]
Further, it is desirable that an optical path conversion mirror is formed in the optical waveguide. This is because the optical path can be changed to a desired angle by forming the optical path conversion mirror.
The optical path conversion mirror can be formed by, for example, machining one end of the optical waveguide as will be described later.
[0037]
The formation position of the optical waveguide is not particularly limited, may be formed between a plurality of interlayer resin insulation layers, may be formed between the interlayer resin insulation layer and the solder resist layer, It may be formed between the substrate and the interlayer resin insulation layer.
[0038]
In the IC chip mounting substrate of the present invention, an optical signal transmission optical path for connecting the optical element and the optical waveguide is provided.
In an IC chip mounting substrate provided with such an optical signal transmission optical path, information is exchanged between optical elements mounted on both surfaces of the IC chip mounting substrate via the optical signal transmission optical path. This can be done by signal.
[0039]
Therefore, the optical path for transmitting an optical signal needs to be configured so that an optical signal can be transmitted between the optical waveguide formed in the IC chip mounting substrate and the optical element.
For example, when the optical element is disposed on the surface of the IC chip mounting substrate and the optical waveguide is formed between the substrate and the interlayer resin insulation layer, or between a plurality of interlayer resin insulation layers, An optical path for transmitting an optical signal needs to be formed in a part of the interlayer resin insulating layer and the solder resist layer so that an optical signal can be exchanged between the light receiving unit or the light emitting unit of the element.
[0040]
The optical path for transmitting an optical signal may be constituted by a gap, may be constituted by a resin composition capable of passing an optical signal, and may be constituted by a gap, and by a resin composition capable of passing an optical signal. It may be configured. When the optical path for transmitting an optical signal is constituted by a gap, the formation thereof is easy. When the optical path for optical signal transmission is constituted by a resin composition and a gap, or when constituted by a resin composition, an IC chip is mounted. It is possible to prevent the strength of the substrate for use from decreasing.
[0041]
When the optical signal transmission optical path is formed of the resin composition and the gap, the optical signal transmission optical path formed in the interlayer resin insulating layer is formed of the resin composition and formed in the solder resist layer. It is desirable that the optical path for optical signal transmission is constituted by a gap. This is because the interlayer resin insulation layer usually has high adhesion to the resin, and the solder resist layer has low adhesion to the resin.
[0042]
When a part or all of the optical path for optical signal transmission is composed of a resin composition, the resin component is not particularly limited as long as it has little absorption in the communication wavelength band, for example, thermosetting Examples thereof include a resin, a thermoplastic resin, a photosensitive resin, a resin in which a part of a thermosetting resin is made photosensitive.
Specifically, for example, epoxy resins, UV curable epoxy resins, polyolefin resins, PMMA (polymethyl methacrylate), deuterated PMMA, acrylic resins such as deuterated fluorinated PMMA, polyimide resins such as fluorinated polyimide, Examples thereof include silicone resins such as deuterated silicone resins, polymers produced from benzocyclobutene, and the like.
[0043]
In addition to the resin component, the resin composition may contain particles such as resin particles, inorganic particles, and metal particles. By including these particles, the thermal expansion coefficient can be matched between the optical path for optical signal transmission and the substrate, the interlayer resin insulation layer, the solder resist layer, etc. Sex can also be imparted.
[0044]
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.
Specifically, the same thing as the resin particle used for the said optical waveguide etc. are mentioned, for example. Moreover, as the resin particles, resin particles made of rubber can be used.
[0045]
Examples of the inorganic particles and the metal particles include those similar to the inorganic particles and metal particles used in the optical waveguide.
These resin particles, inorganic particles and metal particles may be used alone or in combination of two or more.
[0046]
The shape of the particles such as the resin particles is not particularly limited, and examples thereof include a spherical shape, an elliptical spherical shape, a crushed shape, and a polyhedral shape.
The particle size of the particles is preferably shorter than the communication wavelength. This is because if the particle size is longer than the communication wavelength, transmission of the optical signal may be hindered.
[0047]
In addition, the average particle size of the above particles is preferably 0.1 to 20 μm, and particularly preferably 0.5 to 10 μm. If it is the range of this particle size, you may contain the particle | grains of 2 or more types of different particle sizes. That is, the case of containing particles having an average particle diameter of 0.5 to 4 μm and particles having an average particle diameter of 1 to 10 μm.
[0048]
The blending amount of the particles contained in the optical path for transmitting an optical signal is preferably 10 to 80% by weight, and more preferably 20 to 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.
[0049]
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. It is because it can form easily.
[0050]
The cross-sectional diameter of the optical signal transmission optical path is preferably 100 to 500 μm. If the diameter is less than 100 μm, the optical path may be blocked, and when the optical path for transmitting an optical signal is made of a resin composition, it is difficult to fill the uncured resin composition. . On the other hand, even if the diameter is larger than 500 μm, the optical signal transmission performance is not improved so much. In this case, the design freedom of the conductor circuit or the like constituting the IC chip mounting substrate may be hindered. Because.
A more desirable diameter is 250 to 350 μm. This is because both the optical signal transmission property and the degree of freedom in design are excellent, and no inconvenience occurs when the uncured resin composition is filled.
The diameter of the cross section of the optical signal transmission optical path 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.
[0051]
Further, the optical path for transmitting an optical signal may be composed of a void and / or a resin composition and a conductor layer around it.
By forming the conductor layer, irregular reflection of light on the wall surface of the optical path for optical signal transmission can be reduced, and the transmission performance of the optical signal can be improved. The conductor layer may be 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.
Moreover, the said conductor layer can fulfill | perform the role as a via hole depending on the case, ie, the role which electrically connects between the conductor circuits which pinched | interposed the interlayer resin insulation layer. The surface of the conductor layer itself may be roughened by etching or the like.
[0052]
Moreover, you may provide the coating layer and roughening layer which consist of tin, titanium, zinc, etc. further on the said conductor layer. By providing the coating layer and the roughening layer, the irregular reflection of light is further reduced, the optical signal transmission property is improved, and the adhesion between the optical signal transmission optical path and the substrate or the interlayer resin insulation layer is improved. be able to.
[0053]
Moreover, the optical path for optical signal transmission comprised with the said resin composition and the said conductor layer may be in contact with the board | substrate and the interlayer resin insulation layer through the roughening surface. If the optical path for optical signal transmission is in contact with the roughened surface, it has excellent adhesion to the substrate and the interlayer resin insulation layer, and peeling of the optical path for optical signal transmission is less likely to occur. is there.
[0054]
Further, an optical element such as a light receiving element or a light emitting element is mounted on the IC chip mounting substrate 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 IC chip mounting substrate, required characteristics, and the like.
Examples of the material for the light receiving element include Si, Ge, and InGaAs.
Of these, InGaAs is desirable because of its excellent light receiving sensitivity.
[0055]
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 IC chip mounting substrate.
[0056]
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.
[0057]
The mounting position of the optical element is preferably the surface of the IC chip mounting substrate. As described above, when the optical element is mounted on the surface of the IC chip mounting substrate, when a problem occurs in one optical element, only the optical element needs to be replaced.
It is desirable that electronic parts such as capacitors are also mounted on the surface of the IC chip mounting substrate. This is because, as in the case of the optical element described above, it is possible to replace only the parts that have inconveniences.
[0058]
It is desirable that a microlens is formed at an end of the optical signal transmission optical path or in the optical signal transmission optical path. This is because the transmission loss of the optical signal can be further suppressed.
[0059]
Here, the microlens is formed at the end of the optical signal transmission optical path means that the microlens connects the end of the optical signal transmission optical path through an adhesive layer formed on the solder resist layer. A structure in which the microlens is formed on the resin composition when the optical signal transmission optical path is formed by the resin composition when the optical signal transmission optical path is configured to be covered.
On the other hand, a microlens is formed in the optical path for optical signal transmission means that when the optical path for optical signal transmission is composed of a resin composition and an air gap, It means a structure in which the microlens is formed on the resin composition. Moreover, depending on the case, the said resin composition may consist of two layers, and the said micro lens may be formed between the upper layer resin composition and the lower layer resin composition.
[0060]
The microlens is not particularly limited, and examples thereof include those used in optical lenses. Specific examples of the material include optical glass and optical lens resins. Examples of the resin for the optical lens include materials similar to the polymer materials described in the optical waveguide, such as acrylic resin and epoxy resin.
[0061]
In the IC chip mounting substrate of the present invention, the conductor circuits sandwiching the substrate are connected via through holes, and the conductor circuits sandwiching the interlayer resin insulation layer are connected via via holes. It is desirable. This is because the high-density wiring of the IC chip mounting substrate can be realized and the size can be reduced.
[0062]
Next, an embodiment of the IC chip mounting substrate 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 IC chip mounting substrate of the present invention. FIG. 1 shows an IC chip mounting substrate on which an IC chip is mounted.
[0063]
As shown in FIG. 1, in the IC chip mounting substrate 220, the conductor circuit 224 and the interlayer resin insulation layer 222 are laminated on both surfaces of the substrate 221, and between the conductor circuits sandwiching the substrate 221 and between the interlayer resin insulation layers. The conductor circuits sandwiching 222 are electrically connected through a through hole 229 and a via hole 227, respectively, and a solder resist layer 234 is formed in the outermost layer.
[0064]
An optical waveguide 250 is formed on the surface of the substrate 221 together with the lowermost conductor circuit 224, and a portion of the optical waveguide 250 where the optical path conversion mirror is formed is formed on the surface of the IC chip mounting substrate 220. An optical signal transmission optical path 242 that connects the optical elements (the light receiving element 238 and the light emitting element 239) and the optical waveguide 250 is formed in a direction perpendicular to the substrate 221. The optical signal transmission optical path 242 includes a resin composition 242a and a gap 242b and a conductor layer 245 formed therearound.
Note that the optical path for transmitting an optical signal may be formed by a gap, or a conductor layer may not be formed around the optical path.
[0065]
As described above, the light receiving element 238 and the light emitting element 239 are solder-connected to one surface of the IC chip mounting substrate 220 so that the light receiving part 238a and the light emitting part 239a face the optical path 242 for optical signal transmission. The IC chip 240 is surface-mounted via the solder connection portion 243 while being surface-mounted via the portion 244. Solder bumps 237 are formed on the solder resist layer 234 on the other surface of the IC chip mounting substrate 220.
[0066]
In the IC chip mounting substrate 220 having such a configuration, an optical signal sent from the outside via an optical fiber or the like (not shown) is received through the optical waveguide 250 and the optical signal transmission optical path 242. 238 (light receiving portion 238a), then converted into an electrical signal by the light receiving element 238, and further sent to the IC chip 240 via the solder connection portions 243 and 244, the conductor circuit 224, the via hole 227, the through hole 229, and the like. Will be.
[0067]
In addition, the electrical signal sent from the IC chip 240 is sent to the light emitting element 239 through the solder connection portions 243 and 244, the conductor circuit 224, the via hole 227, the through hole 229, and the like, and then the optical signal is output from the light emitting element 239. The optical signal transmitted from the light emitting element 239 (the light emitting unit 239a) is transmitted to the light receiving element on another IC chip mounting substrate via the optical signal transmission optical path 242 and the optical waveguide 250, and is converted into an electrical signal. Or, it is sent out to an external optical element (optical fiber or the like).
[0068]
In the IC chip mounting substrate of the present invention, since the light / electric signal conversion is performed in the light receiving element and the light emitting element mounted near the IC chip, the electric signal transmission distance is short, and the signal transmission reliability is excellent. It is possible to cope with higher speed communication.
[0069]
Further, in the IC chip mounting substrate 220, since the solder bump 237 is formed on the solder resist layer 234 via the metal plating layer, the electrical signal sent from the IC chip is converted into an optical signal as described above. After that, it is not only sent to the outside via the optical path for optical signal transmission 242 but also sent to the external substrate via the solder bump.
[0070]
When the solder bumps are formed as described above, the IC chip mounting substrate can be connected to the external substrate via the solder bumps. In this case, the IC chip is mounted by the self-alignment action of the solder. The mounting substrate can be disposed at a predetermined position.
[0071]
The self-alignment action refers to an action in which the solder tends to exist in a more stable shape near the center of the solder bump forming opening due to the fluidity of the solder during reflow processing, and this action means that the solder is a solder resist layer. It is thought that this occurs due to the strong surface tension that tends to become spherical when the metal is repelled and the solder adheres to the metal.
When this self-alignment action is used, when the IC chip mounting substrate is connected to the external substrate via the solder bumps, even if a positional deviation occurs between both before reflow, The IC chip mounting substrate moves, and the IC chip mounting substrate can be attached to an accurate position on the external substrate.
Therefore, when the optical signal is transmitted between the light receiving element and the light emitting element mounted on the IC chip mounting substrate and the external optical element through the optical waveguide and the optical signal transmission optical path, the IC chip mounting is performed. If the mounting position of the light receiving element and the light emitting element mounted on the circuit board is accurate, an accurate optical signal can be transmitted between the IC chip mounting board and the external board.
[0072]
FIG. 2 is a cross-sectional view schematically showing another embodiment of the IC chip mounting substrate of the present invention. FIG. 2 shows the IC chip mounting substrate on which the IC chip is mounted.
In the IC chip mounting substrate 320 shown in FIG. 2, microlenses 346 a and 346 b are formed on the adhesive layer 347 a at the ends of the optical signal transmission optical path 342 composed of the resin composition 342 a and the gap 342 b and the conductor layer 345. 347b is provided.
Thus, by arranging the microlens, it is possible to suppress the transmission loss of the optical signal.
The embodiment of the IC chip mounting substrate 320 is the same as the embodiment of the IC chip mounting substrate 220 except that the microlenses 346a and 346b are provided.
2, 321 is a substrate, 322 is an interlayer resin insulation layer, 324 is a conductor circuit, 327 is a via hole, 338 is a light receiving element, 339 is a light emitting element, 340 Are IC chips, 343 and 344 are solder connections, and 350 is an optical waveguide.
[0073]
FIG. 16 is a cross-sectional view schematically showing still another embodiment of the IC chip mounting substrate of the present invention. FIG. 16 shows the IC chip mounting substrate on which the IC chip is mounted.
In the IC chip mounting substrate 420 shown in FIG. 16, microlenses 446a and 446b are formed on the resin composition 442a of the optical signal transmission optical path 442 composed of the resin composition 442a, the gap 442b, and the conductor layer 445. ing.
Thus, by forming the microlens, transmission loss of the optical signal can be suppressed.
The embodiment of the IC chip mounting substrate 420 is the same as the embodiment of the IC chip mounting substrate 220 except that the microlenses 446 a and 446 b are formed in the optical signal transmission optical path 442.
In FIG. 16, 421 is a substrate, 422 is an interlayer resin insulating layer, 424 is a conductor circuit, 427 is a via hole, 438 is a light receiving element, 439 is a light emitting element, 440 Is an IC chip, 443 and 444 are solder connections, and 450 is an optical waveguide.
Further, such an IC chip mounting substrate 420 has a structure in which the optical signal transmission optical path 442 is made of a resin composition, and the microlenses 446 a and 446 b are formed at the end of the optical signal transmission optical path 442. May be.
[0074]
The IC chip mounting substrate of the present invention having such a configuration can be manufactured using, for example, the first or second method for manufacturing an IC chip mounting substrate of the present invention.
[0075]
Next, the manufacturing method of the IC chip mounting substrate according to the first aspect of the present invention will be described.
The manufacturing method of the IC chip mounting substrate of the first aspect of the present invention,
A substrate, an optical waveguide, and a laminate manufactured through at least the following steps (a) to (c) are laminated in this order.
(A) a conductor circuit laminate forming step in which a conductor circuit and an interlayer resin insulating layer are sequentially laminated on a base material layer to form a conductor circuit laminate;
(B) an opening forming step for forming an opening to be an optical path for optical signal transmission in the conductor circuit laminate, and
(C) A solder resist layer forming step of forming a solder resist layer having an opening communicating with the opening formed in the step (b) on one side of the conductor circuit laminate.
[0076]
In the IC chip mounting substrate manufacturing method of the first aspect of the present invention, an optical waveguide is formed inside the IC chip mounting substrate, and an opening communicating with the conductor circuit laminate and the solder resist layer is formed. This communicating opening can play a role as an optical path for optical signal transmission. Therefore, the IC chip mounting substrate manufactured by the manufacturing method of the first aspect of the present invention can be used when the optical element is mounted. An optical signal can be suitably transmitted between the element and the optical waveguide via an optical signal transmission optical path.
Further, in the method for manufacturing an IC chip mounting substrate according to the first aspect of the present invention, since there are few steps involving heat treatment after the step of forming the optical waveguide, the light caused by the deformation of the substrate and the interlayer resin insulation layer during the heat treatment. It is possible to suitably manufacture an IC chip mounting substrate that is less likely to be displaced in the waveguide and has excellent connection reliability.
[0077]
In the manufacturing method of the substrate for mounting an IC chip according to the first aspect of the present invention, (A) a substrate manufacturing process, (B) an optical waveguide manufacturing process, and (C) a laminate manufacturing process are performed, and then the manufacturing process is performed. The substrate for mounting an IC chip can be manufactured through the (D) stacking step of stacking the substrate, the optical waveguide, and the stacked body in this order.
Hereinafter, these will be described in order.
[0078]
(A) Board manufacturing process
Using an insulating substrate as a starting material, a conductor circuit is formed on the insulating substrate as necessary.
Examples of the insulating substrate include a glass epoxy substrate, a polyester substrate, a polyimide substrate, a bismaleimide-triazine (BT) resin substrate, a thermosetting polyphenylene ether substrate, a copper clad laminate, and an RCC substrate.
Further, a ceramic substrate such as an aluminum nitride substrate, a silicon base, or the like 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.
[0079]
In addition, when a conductor circuit is formed on the insulating substrate and the connection between the conductor circuits sandwiching the insulating substrate is made through holes, for example, through the insulating substrate using a drill or a laser. After forming the through hole for the hole, the through hole is formed by performing an electroless plating process or the like. In addition, the diameter of the through hole for the through hole is usually 100 to 300 μm.
Further, when a through hole is formed, it is desirable to fill the through hole with a resin filler.
[0080]
(B) Optical waveguide manufacturing process
Here, an optical waveguide formed in a film shape is formed.
When the optical waveguide is an organic optical waveguide made of a polymer material or the like, the organic optical waveguide uses, for example, a selective polymerization method, a method using reactive ion etching and photolithography, a direct exposure method, or an injection molding. It can be formed by forming a polymer material into a film shape on a release film or the like using a method, a photo bleaching method, a method combining these methods, or the like.
When the optical waveguide is an inorganic optical waveguide made of quartz glass, a compound semiconductor, etc., the inorganic optical waveguide is, for example, LiNbO.₃LiTaO₃It is possible to form an inorganic material such as an inorganic material on a release film or the like by using a liquid phase epitaxial method, a chemical deposition method (CVD), a molecular beam epitaxial method, or the like.
[0081]
An optical path conversion mirror is formed in the optical waveguide.
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.
[0082]
(C) Laminate manufacturing process
The laminated body is manufactured through at least the following steps (a) to (c).
(A) a conductor circuit laminate forming step in which a conductor circuit and an interlayer resin insulating layer are sequentially laminated on a base material layer to form a conductor circuit laminate;
(B) an opening forming step for forming an opening to be an optical path for optical signal transmission in the conductor circuit laminate, and
(C) A solder resist layer forming step of forming a solder resist layer having an opening communicating with the opening formed in the step (b) on one side of the conductor circuit laminate.
[0083]
First, the step (a), that is, the conductor circuit laminate forming step for forming the conductor circuit laminate will be described in the order of steps. Specifically, it can be performed, for example, through the following steps (1) to (9).
(1) A base material layer formed into a film is used as a starting material, and a conductor circuit is formed on the base material layer.
Examples of the base material layer include a thermosetting resin, a photosensitive resin, a resin in which a part of the thermosetting resin is acrylated, and an uncured resin made of a resin composite containing these and a thermoplastic resin. May be formed into a film and cured, or may be formed from a thermoplastic resin or the like.
[0084]
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.
[0085]
As said photosensitive resin, an acrylic resin etc. are mentioned, for example.
Moreover, as resin which acrylated a part of said thermosetting resin, what made the acrylate reaction of the thermosetting group of the above-mentioned thermosetting resin, methacrylic acid, and acrylic acid etc. are mentioned, for example.
[0086]
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.
[0087]
The resin composite is not particularly limited as long as it includes a thermosetting resin or a photosensitive resin (including a resin obtained by acrylating a part of the thermosetting resin) and a thermoplastic resin. Specific examples of the combination of the curable resin and the thermoplastic resin include phenol resin / polyether sulfone, polyimide resin / polysulfone, epoxy resin / polyether sulfone, and epoxy resin / phenoxy resin. Specific examples of the combination of the photosensitive resin and the thermoplastic resin include an acrylic resin / phenoxy resin, and an epoxy resin / polyether sulfone in which a part of the epoxy group is acrylated.
[0088]
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.
Moreover, the said base material layer may be comprised from two or more different resin layers.
[0089]
Moreover, the said base material layer may shape | mold the roughening surface formation resin composition in the film form, and gave the hardening process. The roughened surface-forming resin composition will be described in detail later when a method for forming an interlayer resin insulating layer is described.
[0090]
The conductor circuit formed on the base material layer can be formed, for example, by forming a solid conductor layer on the surface of the base material layer by electroless plating or the like and then performing an etching process or the like. .
In addition, instead of the method of forming a conductor circuit by performing an etching process, a partial plating resist on the solid conductor layer is formed, and then an electrolytic plating layer is formed on the plating resist non-forming portion, The conductor circuit may be formed by using a method of removing the plating resist and the conductor layer existing under the plating resist.
[0091]
In addition, in the case where connection between conductor circuits sandwiching the base material layer is made through holes, for example, through holes for through holes are formed in the base material layer using a laser or the like, and then electroless plating treatment or the like is performed. Through holes are formed by applying. In addition, the diameter of the through hole for the through hole is usually 100 to 300 μm.
Further, when a through hole is formed, it is desirable to fill the through hole with a resin filler.
[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.
Here, when the roughened surface is formed, the average roughness of the roughened surface is usually preferably 0.1 to 5 μm, the adhesion between the conductor circuit and the interlayer resin insulating layer, the electric signal transmission capability of the conductor circuit. 2-4 μm is more desirable in view of the influence on the above.
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 the base material layer on which the conductor circuit is formed, a thermosetting resin, a photosensitive resin, a resin in which a part of the thermosetting resin is acrylated, or a resin composite including these and a thermoplastic resin An uncured resin layer made of a body is formed, or a resin layer made of a thermoplastic resin is formed. In addition, the resin similar to the resin used when forming a base material layer etc. can be used for formation of these resin layers, for example.
[0094]
Moreover, the uncured resin layer and the resin layer made of thermoplastic resin formed here 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 composed of 10 resin composites.
With such a configuration, it is possible to ensure excellent adhesion with the substrate and ease of formation when forming a via hole opening or the like in a later step.
[0095]
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 the said thermoplastic resin can be formed by thermocompression-bonding the resin molded object shape | molded on the film.
[0096]
The thermocompression bonding of the resin composite or the resin molded body can be performed 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.
[0097]
The uncured resin layer may be formed using a roughened surface-forming resin composition.
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 solution 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.
[0098]
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.
[0099]
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.
[0100]
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.
[0101]
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.
[0102]
Examples of the substance that is soluble in the roughening liquid consisting of at least one selected from acids, alkalis, and oxidizing agents include inorganic particles, resin particles, metal particles, rubber particles, liquid phase resins, and liquid phase rubbers. Particles and the like. Among these, inorganic particles, resin particles, and metal particles are desirable.
[0103]
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.
The alumina particles can be dissolved and removed with hydrofluoric acid, and calcium carbonate can be dissolved and removed with hydrochloric acid. Sodium-containing silica and dolomite can be dissolved and removed with an alkaline aqueous solution.
[0104]
Examples of the resin particles include those made of a thermosetting resin, a thermoplastic resin, and the like. When the resin particles are immersed in a roughening solution made of at least one selected from an acid, an alkali, and an oxidizing agent, the heat resistance It is not particularly limited as long as it has a faster dissolution rate than the resin matrix. Specifically, for example, amino resins (melamine resins, urea resins, guanamine resins, etc.), epoxy resins, phenol resins, phenoxy resins, polyimide resins, Examples include those made of polyphenylene resin, polyolefin resin, fluororesin, bismaleimide-triazine resin and the like. These may be used alone or in combination of two or more.
The resin particles must be previously cured. This is because if the resin is not cured, the resin particles will be dissolved in a solvent for dissolving the resin matrix.
[0105]
As said metal particle, what consists of gold, silver, copper, tin, zinc, stainless steel, aluminum, nickel, iron, lead etc. is mentioned, for example. 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.
[0106]
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 between the poorly soluble resin and the interlayer resin comprising 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.
[0107]
Examples of the acid used as the roughening solution include phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, and organic acids such as formic acid and acetic acid. Among these, it is desirable to use an organic acid. This is because when the roughening treatment is performed, the metal conductor layer exposed from the via hole is hardly corroded.
As the oxidizing agent, for example, an aqueous solution of chromic acid, chromium sulfuric acid, alkaline permanganate (such as potassium permanganate), or the like is preferably used.
Moreover, as said alkali, aqueous solution, such as sodium hydroxide and potassium hydroxide, is desirable.
[0108]
The average particle size of the soluble substance is desirably 10 μm or less.
Further, coarse particles having a relatively large average particle diameter and fine particles 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 0.8 μm and a soluble substance having an average particle diameter of 0.8 to 2.0 μm are combined.
[0109]
Thus, by combining the average particles, relatively large coarse particles, and fine particles having a relatively small average particle diameter, the dissolution residue of the thin film conductor layer is eliminated, and the amount of palladium catalyst under the plating resist is reduced. 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.
[0110]
(4) Next, when forming an interlayer resin insulation layer using a thermosetting resin or a 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, through-holes for through holes may be formed as necessary.
The via hole opening is preferably formed by laser processing. Further, when a photosensitive resin is used as the material for the interlayer resin insulation layer, it may be formed by exposure and development processing.
[0111]
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.
In addition, when the through hole for the through hole is formed in this step, the through hole for the through hole may be formed by laser processing or the like.
[0112]
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.
[0113]
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 number of via holes are formed in the resin layer by one irradiation. The opening for use can be formed efficiently.
[0114]
When a carbon dioxide laser is used, the pulse interval is 10^-4-10^-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 laser light having the same intensity and the same irradiation intensity can be irradiated to a plurality of portions through the optical system lens and the mask.
After forming the via hole opening in this manner, desmear treatment may be performed as necessary.
[0115]
In addition, it is desirable that the material of the interlayer resin insulation layer formed in this step is the same as the material of the base material layer.
This is because the physical properties such as the coefficient of thermal expansion are the same between the two.
[0116]
(5) Next, a thin film conductor layer is formed on the surface of the interlayer resin insulating layer including the inner wall of the via hole opening.
The thin film conductor layer can be formed, for example, by a method such as electroless plating or sputtering.
[0117]
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 to 2.0 [mu] m, more preferably 0.6 to 1.2 [mu] m when the thin film conductor layer is formed by electroless plating. Moreover, when forming by sputtering, 0.1-1.0 micrometer is desirable.
[0118]
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.
[0119]
Further, when the through hole for the through hole is formed in the step (4), when the thin film conductor layer is formed on the interlayer resin insulating layer, the thin film conductor layer is also formed on the wall surface of the through hole. It may be a through hole.
[0120]
(6) Next, a plating resist is formed on a part of the interlayer resin insulation layer having the thin film conductor layer formed on the surface thereof.
The plating resist can be formed, for example, by sticking a photosensitive dry film, placing a photomask made of a glass substrate or the like on which a plating resist pattern is drawn, and performing exposure and development processing.
[0121]
(7) Thereafter, an electrolytic plating solution is applied using the thin film conductor layer as a plating lead, and an electrolytic plating layer is formed on the plating resist non-forming portion. As the electrolytic plating solution, copper plating is desirable.
The thickness of the electrolytic plating layer is preferably 5 to 20 μm.
[0122]
Then, a conductor circuit (including a via hole) can be formed by removing the plating resist and the thin film conductor layer under the plating resist.
The plating resist may be removed using, for example, an alkaline aqueous solution, and the thin film conductor layer may be removed using a mixed solution of sulfuric acid and hydrogen peroxide, sodium persulfate, ammonium persulfate, ferric chloride, chloride. What is necessary is just to perform using etching liquid, such as cupric.
Moreover, after forming the said conductor circuit, you may remove the catalyst on an interlayer resin insulation layer using an acid or an oxidizing agent as needed. This is because deterioration of electrical characteristics can be prevented.
Moreover, after forming this plating resist, it replaces with the method (process (6) and (7)) of forming an electroplating layer, forms an electroplating layer on the whole surface on a thin film conductor layer, and performs an etching process. Thus, a method of forming a conductor circuit may be used.
[0123]
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.
[0124]
(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 interlayer resin insulation layer is formed. In this step, a through hole may be formed or may not be formed.
(9) Furthermore, the conductor circuit and the interlayer resin insulating layer may be laminated by repeating the steps (5) to (8) as necessary.
[0125]
Through the steps (1) to (9), a conductor circuit laminate in which a conductor circuit and an interlayer resin insulating layer are laminated on both surfaces of the base material layer can be manufactured.
In addition, although the manufacturing method of the conductor circuit laminated body detailed here is a semi-additive method, the manufacturing method of the conductor circuit laminated body manufactured at the process of said (a) is not limited to a semi-additive method, A full additive method, A subtractive method, a batch lamination method, a conformal method, or the like can also be used.
Among these, the semi-additive method or the full additive method is desirable. This is because the etching accuracy is high, so that it is suitable for forming a finer conductor circuit and the degree of freedom in designing the conductor circuit is improved.
[0126]
After the conductor circuit laminate is manufactured through the step (a), the step (b), that is, the opening forming step of forming an opening serving as an optical path for transmitting an optical signal in the conductor circuit laminate is performed. The opening formed in this step serves as an optical path for optical signal transmission in the IC chip mounting substrate. Therefore, the opening formed in this step is hereinafter referred to as an optical signal transmission opening.
[0127]
The optical signal transmission opening is formed by, for example, laser processing.
Examples of the laser used in the laser treatment include those similar to the laser used in forming the via hole opening.
The formation position of the optical signal transmission opening is not particularly limited, and may be appropriately selected in consideration of the design of the conductor circuit, the mounting position of the IC chip, and the like.
The optical signal transmission opening is preferably formed for each optical element such as a light receiving element or a light emitting element. Moreover, you may form for every signal wavelength.
[0128]
In addition, after forming the optical signal transmission opening, desmearing may be performed on the wall surface of the optical signal transmission opening as necessary. The desmear treatment can be performed using, for example, a treatment with a permanganic acid solution, a plasma treatment, a corona treatment, or the like. By performing the desmear process, resin residue, burrs, etc. in the optical signal transmission opening can be removed, and transmission loss due to irregular reflection on the wall surface of the optical path for optical signal transmission can be reduced. .
[0129]
In addition, after forming the optical signal transmission opening, before forming the conductor layer in the following steps or filling the uncured resin composition, the wall surface of the optical signal transmission opening may be roughened as necessary. It is desirable to perform the roughened surface forming step. This is because the adhesion to the conductor layer and the resin composition can be improved.
The roughened surface is formed by, for example, forming an optical signal transmission opening such as 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 part. It can also be performed by plasma treatment, corona treatment, or the like.
The average roughness (Ra) of the roughened surface is desirably 0.5 to 5 μm, and more desirably 1 to 3 μm. This is because within this range, the adhesiveness with the conductor layer and the resin composition is excellent, and the transmission of the optical signal is not adversely affected.
[0130]
After forming the optical signal transmission opening, it is desirable to perform a conductor layer forming step of forming a conductor layer on the wall surface of the optical signal transmission opening, if necessary.
The conductor layer can be formed, for example, by a method such as electroless plating or sputtering.
Specifically, for example, after forming the optical signal transmission opening, a catalyst nucleus is applied to the wall surface of the optical signal transmission opening, and then the substrate on which the optical signal transmission opening is formed is used as an electroless plating bath. A dipping method or the like 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.
[0131]
In such a conductor layer forming step, a conductor layer is formed on the wall surface of the optical signal transmission opening, and the outermost layer conductor circuit is formed on the outermost interlayer resin insulation layer formed in the step (a). It is desirable to form.
Specifically, first, when the conductor layer is formed on the wall surface of the optical signal transmission opening by electroless plating or the like, the conductor layer is also formed on the entire surface of the interlayer resin insulating layer.
[0132]
Next, a plating resist is formed on the conductor layer formed on the surface of the interlayer resin insulation layer. The plating resist may be formed, for example, by attaching a photosensitive dry film, then closely contacting a photomask made of a glass substrate or the like on which the plating resist pattern is drawn, and performing an exposure development process.
[0133]
Furthermore, electrolytic plating is performed using the conductor layer formed on the interlayer resin insulation layer as a plating lead, and an electrolytic plating layer is formed on the plating resist non-forming portion, and then the plating resist and the conductor layer under the plating resist are formed. By removing, an independent conductor circuit is formed on the outermost interlayer resin insulation layer.
[0134]
Further, after forming the conductor layer, a roughened surface may be formed on the wall surface of the conductor layer. The roughened surface is formed by, for example, blackening (oxidation) -reduction treatment, etching treatment using an etchant containing a cupric complex and an organic acid salt, or treatment by Cu-Ni-P needle-shaped alloy plating. Etc. can be used.
[0135]
Moreover, after forming the said optical signal transmission opening, it is desirable to perform the resin composition filling process which fills this opening with an uncured resin composition as needed.
After filling with an uncured resin composition, an optical signal transmission optical path composed of the resin composition and the gap or an optical signal transmission optical path composed of the resin composition is formed by performing a curing treatment. be able to.
A specific filling method of the uncured resin composition is not particularly limited, and for example, a method such as printing or potting can be used.
When filling the uncured resin composition by printing, the uncured resin composition may be printed once, or may be printed twice or more. Moreover, you may print from both surfaces of a conductor circuit laminated body.
[0136]
Further, when filling the uncured resin composition, the uncured resin composition is filled in an amount slightly larger than the inner product of the optical signal transmission opening. You may remove the excess resin composition which overflowed.
The excess resin composition can be removed by, for example, polishing. Further, when removing the excess resin composition, the state of the resin composition may be a semi-cured state or a completely cured state, which is appropriately determined in consideration of the material of the resin composition and the like. Just choose.
In addition, when not performing the said resin composition filling process, the optical path for optical signal transmission comprised from a space | gap can be formed.
[0137]
Conductor circuit laminate manufactured through the step (a) by passing through such an opening forming step and a roughened surface forming step, a conductor layer forming step, and a resin composition filling step, which are performed as necessary. A part of the optical path for optical signal transmission can be formed.
Moreover, when performing the said conductor layer formation process, an independent conductor circuit can be formed by forming a conductor layer also on the surface of an interlayer resin insulation layer and performing the process mentioned above. Of course, even when the step of forming the conductor layer is not performed, the conductor circuit can be formed on the surface of the interlayer resin insulating layer by the method described above.
[0138]
Next, the step (c), that is, a solder resist layer forming step for forming a solder resist layer having an opening communicating with the opening formed in the step (b) is performed. Specifically, for example, the solder resist layer can be formed by performing the following steps (1) and (2).
In addition, what is necessary is just to form a soldering resist layer in the single side | surface of a conductor circuit laminated body.
[0139]
(1) First, a layer of a solder resist composition is formed on one side of a conductor circuit laminate in which an optical signal transmission opening is formed.
The layer of the solder resist composition can be formed using, for example, a solder resist composition made of polyphenylene ether resin, polyolefin resin, fluororesin, thermoplastic elastomer, epoxy resin, polyimide resin or the like.
[0140]
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.
Moreover, you may press-bond the film which consists of the said soldering resist composition, and may form the layer of a soldering resist composition. In particular, when the optical signal transmission opening is constituted by a gap, it is desirable to form a solder resist composition layer by pressure-bonding the film.
[0141]
(2) Next, an opening communicating with the optical signal transmission opening (hereinafter also referred to as an optical path opening) is formed in the solder resist composition layer.
Specifically, for example, it can be formed by exposure development processing, laser processing, or the like.
Further, when forming the optical path opening, it is desirable to form the solder bump forming opening at the same time. The formation of the optical path opening and the formation of the solder bump forming opening may be performed separately.
Also, when forming the solder resist layer, a solder resist layer having an opening for an optical path and an opening for forming a solder bump is prepared by preparing a resin film having an opening at a desired position in advance and pasting the resin film. May be formed.
[0142]
The cross-sectional diameter of the optical path opening may be smaller than the cross-sectional diameter of the optical signal transmission opening. In this case, the diameter of the cross section of the optical path opening may be 20 to 100 μm smaller than the diameter of the cross section of the optical signal transmission opening.
[0143]
Through the steps (1) and (2), a solder resist layer having an opening communicating with the optical signal transmission opening is formed on one surface of the conductor circuit laminate in which the optical signal transmission opening is formed. Can be formed.
In the method for manufacturing an IC chip mounting substrate according to the first aspect of the present invention, a solder resist layer may be formed after the (D) laminating step described later.
[0144]
When the optical signal transmission opening is filled with an uncured resin composition in the opening formation step (b), the optical path opening formed in the solder resist layer is the same as the optical signal transmission opening. The uncured resin composition may be filled by this method. After filling the uncured resin composition into the optical path opening of the solder resist layer in this way, the uncured resin composition is subjected to a curing treatment to thereby form an optical signal transmission optical path composed of the resin composition. Can be formed.
[0145]
After performing the steps (a) to (c), for example, a laminate can be manufactured by performing solder pad formation using the following method.
That is, the conductor circuit portion exposed by forming the solder bump forming opening is coated with a corrosion-resistant metal such as nickel, palladium, gold, silver, platinum, or the like, as necessary, to form a solder pad. In these, it is desirable to form a coating layer with metals, such as nickel-gold, nickel-silver, nickel-palladium, nickel-palladium-gold.
The coating layer can be formed by, for example, plating, vapor deposition, electrodeposition, or the like. Among these, it is desirable to form by plating from the viewpoint that the uniformity of the coating layer is excellent.
[0146]
(D) Lamination process
The optical waveguide manufactured in the step (B) and the laminate manufactured in the step (C) are stacked on the substrate manufactured in the step (A).
This lamination is desirably performed by thermocompression bonding, and can be performed using, for example, a vacuum laminator or the like.
The pressure bonding conditions are not particularly limited, and may be appropriately selected in consideration of the composition of the resin used for the optical waveguide and the laminated body. Usually, the pressure is 0.2 to 1. under vacuum or reduced pressure. It is desirable to carry out under the conditions of 0 MPa, temperature 50 to 200 ° C., and time 30 to 600 seconds.
[0147]
In addition, the optical waveguide is previously laminated on the substrate, and the laminated body may be laminated thereon, or the optical waveguide is previously formed on the outermost interlayer resin insulating layer of the laminated body, This may be laminated on the substrate.
[0148]
Further, after the lamination process, a microlens formation process for forming a microlens at the end of the optical path for transmitting an optical signal may be performed as necessary. This is because the transmission loss of the optical signal can be further suppressed.
In order to form a 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 via an adhesive layer formed on the solder resist layer (see FIG. 2). In addition, when the optical path for transmitting an optical signal is composed of a resin composition, it may be formed directly on the resin composition.
[0149]
As a method of directly forming the microlens on the resin composition, for example, an appropriate amount of uncured optical lens resin is dropped on the resin composition, and the dripped uncured optical lens resin is cured. A method can be mentioned.
In the above method, when an appropriate amount of uncured optical lens resin is dropped onto the resin composition, an apparatus such as a dispenser, an inkjet, a micropipette, or a microsyringe can be used. Further, the uncured resin for an optical lens dropped on the resin composition using such an apparatus tends to be spherical due to the surface tension, and thus becomes hemispherical on the resin composition, and then hemispherical. A hemispherical microlens can be formed on the resin composition by curing the uncured optical lens resin.
Examples of the optical lens resin include materials similar to the polymer materials described in the optical waveguide of the IC chip mounting substrate of the present invention, such as acrylic resin and epoxy resin.
In addition, the diameter of the microlens formed in this way, the shape of the curved surface, etc., the viscosity of the uncured optical lens resin, etc., as appropriate, considering the wettability between the resin composition and the uncured optical lens resin It can be controlled by adjusting.
[0150]
In the method for manufacturing an IC chip mounting substrate according to the first aspect of the present invention, a microlens forming step of forming a microlens in the optical path for transmitting an optical signal may be performed. This is because even in this case, transmission loss of the optical signal can be further suppressed.
In order to form a microlens in the optical path for optical signal transmission, when the optical path for optical signal transmission is composed of a resin composition and a gap, the resin composition is inside the optical path for optical signal transmission. It may be formed directly on the top (see FIG. 16). In some cases, the resin composition has a two-layer structure, and the microlenses are formed between the upper resin composition and the lower resin composition. May be.
[0151]
As a method of forming a microlens in the optical signal transmission optical path, when the optical signal transmission optical path is composed of a resin composition and a gap, an optical lens resin is formed at the end of the optical signal transmission optical path. A method similar to the method of forming a microlens made of
Further, when the resin composition has a two-layer structure, in the conductor circuit laminate before forming the solder resist layer, after filling and curing the uncured resin composition in the optical signal transmission opening, On the cured resin composition, a microlens made of a resin for optical lenses is formed by the method described above, and then a solder resist layer is formed on the conductor circuit laminate, and the optical path opening of the solder resist layer is formed. By filling an uncured resin composition and curing, a microlens can be formed between the upper resin composition and the lower resin composition.
[0152]
Furthermore, the IC chip mounting substrate of the present invention can be manufactured by forming solder bumps and mounting optical elements (light receiving elements and light emitting elements) on the solder resist layer.
The solder bumps are formed by reflowing after filling the solder pads with a solder paste through a mask having openings formed in portions corresponding to the solder pads.
Moreover, the mounting of the optical element can be performed through the solder bump, for example. For example, when forming the solder bump, the optical element may be mounted at the time when the solder paste is filled, and the optical element may be mounted simultaneously with the reflow.
Further, the optical element may be mounted using a conductive adhesive or the like instead of the solder.
Through such steps, the IC chip mounting substrate of the present invention can be suitably manufactured.
[0153]
Next, the manufacturing method of the IC chip mounting substrate of the second aspect of the present invention will be described.
The manufacturing method of the IC chip mounting substrate of the second aspect of the present invention,
(A) an optical waveguide forming step of forming an optical waveguide on a substrate on which a conductor circuit is formed;
(B) A multilayer wiring board manufacturing process in which an interlayer resin insulating layer and a conductor circuit are sequentially laminated on the substrate on which the optical waveguide is formed, to form a multilayer wiring board;
(C) an opening forming step of forming an opening serving as an optical path for optical signal transmission in the multilayer wiring board;
(D) a solder resist layer forming step of forming a solder resist layer having an opening communicating with the opening formed in the step (c) on one side of the multilayer wiring board;
It is characterized by including.
[0154]
In the IC chip mounting substrate manufacturing method of the second aspect of the present invention, an optical waveguide is formed inside the IC chip mounting substrate, and an opening communicating with the conductor circuit laminate and the solder resist layer is formed. This communicating opening can play a role as an optical path for optical signal transmission. Therefore, the IC chip mounting substrate manufactured by the manufacturing method of the second aspect of the present invention can be used when the optical element is mounted. An optical signal can be suitably transmitted between the element and the optical waveguide via an optical signal transmission optical path.
[0155]
First, the step (a), that is, the optical waveguide forming step of forming the optical waveguide on the substrate on which the conductor circuit is formed will be described in the order of steps. Specifically, for example, the optical waveguide can be formed through the following steps (1) to (3).
[0156]
(1) Using an insulating substrate as a starting material, first, a conductor circuit is formed on the insulating substrate.
Examples of the insulating substrate include a glass epoxy substrate, a polyester substrate, a polyimide substrate, a bismaleimide-triazine (BT) resin substrate, a thermosetting polyphenylene ether substrate, a copper clad laminate, and an RCC substrate.
Further, a ceramic substrate such as an aluminum nitride substrate or a silicon substrate may be used.
[0157]
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.
Further, instead of the method of forming a conductor circuit by performing an etching process, after forming a plating resist on the solid conductor layer, an electroplating layer is formed on the plating resist non-forming portion, and then the plating resist and the The conductor circuit may be formed using a method of forming a conductor circuit by removing the conductor layer under the plating resist.
In addition, you may form the said conductor circuit after the process of (3) mentioned later.
[0158]
In addition, in the case where connection between conductor circuits sandwiching the insulating substrate is performed through holes, for example, after forming through holes for through holes on the insulating substrate using a drill or a laser, electroless plating is performed. Through-holes are formed by processing or the like. In addition, the diameter of the through hole for the through hole is usually 100 to 300 μm.
Further, when a through hole is formed, it is desirable to fill the through hole with a resin filler.
[0159]
(2) Next, the surface of the conductor circuit is roughened as necessary.
Examples of the roughening treatment include blackening (oxidation) -reduction treatment, etching treatment using an etchant containing a cupric complex and an organic acid salt, and treatment by Cu—Ni—P needle-like alloy plating. Etc.
Here, when the roughened surface is formed, the average roughness of the roughened surface is usually preferably 0.1 to 5 μm, the adhesion between the conductor circuit and the interlayer resin insulating layer, the electric signal transmission capability of the conductor circuit. 2-4 μm is more desirable in view of the influence on the above.
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.
[0160]
(3) Next, an optical waveguide is formed in the conductor circuit non-formation part on the substrate.
When an organic optical waveguide made of a polymer material or the like is formed as an optical waveguide, the optical waveguide previously formed into a film shape on a release film or the like is pasted on the substrate or directly formed on the substrate. By doing so, an optical waveguide can be formed. Specifically, it can be formed using a selective polymerization method, a method using reactive ion etching and photolithography, a direct exposure method, a method using injection molding, a photo bleaching method, a method combining these, and the like. .
These methods can be used both when the optical waveguide is formed on a release film or the like or when it is directly formed on the substrate.
When an inorganic optical waveguide made of quartz glass, a compound semiconductor, or the like is formed as the optical waveguide, for example, LiNbO₃LiTaO₃Inorganic optical waveguides such as quartz glass that have been formed into films by liquid phase epitaxy, chemical deposition (CVD), molecular beam epitaxy, etc. It can be performed by attaching via an adhesive.
[0161]
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 substrate, but the optical waveguide is formed directly on the substrate. Except in some cases, it is desirable to form an optical path conversion mirror in advance. This is because the work can be easily performed, and there is no risk of damaging or damaging other members constituting the IC chip mounting board, for example, the conductor circuit or the board during the work. .
As a method for forming the optical path conversion mirror, the same method as that used in the (B) optical waveguide manufacturing process in the manufacturing method of the IC chip mounting substrate of the first aspect of the present invention can be used.
[0162]
Also, as described above, after forming the optical waveguide in the step (3), a conductor circuit may be formed on the insulating substrate. In this case, a plating resist is formed on the solid conductor layer. After that, it is desirable to form a conductive circuit by a method of forming an electrolytic plating layer in the plating resist non-forming portion and further removing the plating resist and the solid conductor layer under the plating resist. This is because there is little possibility of damaging the formed optical waveguide.
[0163]
Next, a multilayer wiring board manufacturing process in which the interlayer resin insulating layer and the conductor circuit are sequentially laminated on the substrate on which the optical waveguide is formed in the process (b), that is, the process (a). The steps will be described in the order of steps. Specifically, for example, a multilayer wiring board can be manufactured through the following steps (1) to (7).
[0164]
(1) On the substrate on which the optical waveguide is formed in the step (a), a thermosetting resin, a photosensitive resin, a resin in which a part of the thermosetting resin is acrylated, and these and a thermoplastic resin An uncured resin layer made of the resin composite is formed, or a resin layer made of a thermoplastic resin is formed.
Specifically, in the manufacturing method of the IC chip mounting substrate of the first aspect of the present invention, (a) a resin similar to the resin used when forming the interlayer resin insulating layer in the conductor circuit laminate forming step is used. it can.
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 the said thermoplastic resin can be formed by thermocompression-bonding the resin molded object shape | molded on the film.
[0165]
The thermocompression bonding of the resin composite or the resin molded body can be performed 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.
[0166]
(2) 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, through-holes for through holes may be formed as necessary.
The via hole opening is preferably formed by laser processing. Further, when a photosensitive resin is used as the material for the interlayer resin insulation layer, it may be formed by exposure and development processing.
[0167]
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 the through hole for the through hole is formed in this step, the through hole for the through hole may be formed by drilling, laser processing, or the like.
[0168]
As the laser used for the laser processing, for example, in the (a) conductor circuit laminate forming step in the method for manufacturing an IC chip mounting substrate of the first aspect of the present invention, a laser used when forming a via hole opening And the like.
[0169]
(3) Next, a conductor circuit is formed on the surface of the interlayer resin insulation layer including the inner wall of the via hole opening.
Specifically, for example, a method similar to the method used in (5) to (7) of the (a) conductor circuit laminate forming step in the method for manufacturing an IC chip mounting substrate of the first invention is used. Can do.
Also in this step, a through hole may be formed in the same manner as in the above (a) conductor circuit laminate forming step. When a through hole is formed, a resin filler is filled in the through hole. Also good.
Further, when the resin filler is filled in the through hole, a lid plating layer that covers the resin filler layer may be formed by electroless plating or the like.
[0170]
(4) Next, when a lid plating layer is formed, if necessary, the surface of the lid plating layer is roughened, and the steps (1) and (2) are repeated. An interlayer resin insulation layer is formed. In this step, a through hole may be formed or may not be formed.
(5) Further, if necessary, the conductor circuit and the interlayer resin insulating layer may be laminated by repeating the steps (3) and (4).
[0171]
By performing such steps (1) to (5), 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.
The manufacturing method of the multilayer wiring board detailed here is the semi-additive method, but the manufacturing method of the multilayer wiring board manufactured in the step (a) is not limited to the semi-additive method, and the full-additive method and the subtractive method. It is also possible to use a method, a batch lamination method, a conformal method or the like. Among these, the semi-additive method or the full-additive method is desirable because it is excellent as a method for forming a fine conductor circuit.
[0172]
In the manufacturing method of the IC chip mounting substrate of the second aspect of the present invention, after the multilayer wiring board is manufactured through the steps (a) and (b), the step (c), that is, the multilayer wiring is performed. An opening forming step for forming an opening to be an optical signal transmission optical path on the plate is performed. The opening formed in this step serves as an optical signal transmission optical path for connecting the optical element and the optical waveguide in the IC chip mounting substrate. Therefore, the opening formed in this step is hereinafter referred to as an optical signal transmission opening.
[0173]
The optical signal transmission opening is formed by, for example, laser processing.
Examples of the laser used in the laser treatment include those similar to the laser used in forming the via hole opening.
In this case, it is desirable to use a laser having a wavelength at which the optical waveguide does not absorb as the laser. This is because the surface of the optical waveguide is less likely to be damaged when the optical signal transmission opening is formed.
The formation position of the optical signal transmission opening is not particularly limited, and may be appropriately selected in consideration of the design of the conductor circuit, the mounting position of the IC chip, and the like.
The optical signal transmission opening is preferably formed for each optical element such as a light receiving element or a light emitting element. Moreover, you may form for every signal wavelength.
[0174]
In addition, after forming the optical signal transmission opening, desmearing may be performed on the wall surface of the optical signal transmission opening as necessary. The desmear treatment can be performed using, for example, a treatment with a permanganic acid solution, a plasma treatment, a corona treatment, or the like. By performing the desmear process, resin residue, burrs, etc. in the optical signal transmission opening can be removed, and transmission loss due to irregular reflection on the wall surface of the optical path for optical signal transmission can be reduced. .
[0175]
In addition, after forming the optical signal transmission opening, before forming the conductor layer in the following steps or filling the uncured resin composition, the wall surface of the optical signal transmission opening may be roughened as necessary. It is desirable to perform the roughened surface forming step. This is because the adhesion to the conductor layer and the resin composition can be improved.
The roughened surface is formed by, for example, forming an optical signal transmission opening such as 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 part. It can also be performed by plasma treatment, corona treatment, or the like.
The average roughness (Ra) of the roughened surface is desirably 0.5 to 5 μm, and more desirably 1 to 3 μm. This is because within this range, the adhesiveness with the conductor layer and the resin composition is excellent, and the transmission of the optical signal is not adversely affected.
[0176]
After forming the optical signal transmission opening, it is desirable to perform a conductor layer forming step of forming a conductor layer on the wall surface of the optical signal transmission opening, if necessary.
The conductor layer can be formed, for example, by a method such as electroless plating or sputtering.
Specifically, for example, after forming the optical signal transmission opening, a catalyst nucleus is applied to the wall surface of the optical signal transmission opening, and then the substrate on which the optical signal transmission opening is formed is used as an electroless plating bath. A dipping method or the like 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.
[0177]
In such a conductor layer forming step, a conductor layer is formed on the wall surface of the optical signal transmission opening, and an outermost conductor circuit is formed on the interlayer resin insulation layer formed through the step (b). It is desirable to do.
Specifically, first, when the conductor layer is formed on the wall surface of the optical signal transmission opening by electroless plating or the like, the conductor layer is also formed on the entire surface of the interlayer resin insulating layer.
[0178]
Next, a plating resist is formed on the conductor layer formed on the surface of the interlayer resin insulation layer. The plating resist may be formed, for example, by attaching a photosensitive dry film, then closely contacting a photomask made of a glass substrate or the like on which the plating resist pattern is drawn, and performing an exposure development process.
[0179]
Furthermore, electrolytic plating is performed using the conductor layer formed on the interlayer resin insulation layer as a plating lead, and an electrolytic plating layer is formed on the plating resist non-forming portion, and then the plating resist and the conductor layer under the plating resist are formed. By removing, an independent conductor circuit is formed on the interlayer resin insulation layer.
[0180]
Further, after forming the conductor layer, a roughened surface may be formed on the wall surface of the conductor layer. The roughened surface is formed by, for example, blackening (oxidation) -reduction treatment, etching treatment using an etchant containing a cupric complex and an organic acid salt, or treatment by Cu-Ni-P needle-shaped alloy plating. Etc. can be used.
[0181]
Moreover, after forming the said optical signal transmission opening, it is desirable to perform the resin filling process which fills this opening with an unhardened resin composition as needed.
After filling with an uncured resin composition, an optical signal transmission optical path composed of the resin composition and the gap or an optical signal transmission optical path composed of the resin composition is formed by performing a curing treatment. be able to.
A specific filling method of the uncured resin composition is not particularly limited, and for example, a method such as printing or potting can be used.
When filling the uncured resin composition by printing, the uncured resin composition may be printed once, or may be printed twice or more.
[0182]
Further, when filling the uncured resin composition, the uncured resin composition is filled in an amount slightly larger than the inner product of the optical signal transmission opening. You may remove the excess resin composition which overflowed.
The excess resin composition can be removed by, for example, polishing. Further, when removing the excess resin composition, the state of the resin composition may be a semi-cured state or a completely cured state, which is appropriately determined in consideration of the material of the resin composition and the like. Just choose.
In addition, when not performing the said resin composition filling process, the optical path for optical signal transmission comprised from a space | gap can be formed.
[0183]
Through the steps (a) and (b) above through the opening forming step and the roughened surface forming step, the conductor layer forming step, and the resin composition filling step performed as necessary. A part of the optical path for optical signal transmission can be formed on the manufactured multilayer wiring board. Moreover, when performing the said conductor layer formation process, an independent conductor circuit can be formed by forming a conductor layer also on the surface of an interlayer resin insulation layer and performing the process mentioned above. Of course, even when the step of forming the conductor layer is not performed, the conductor circuit can be formed on the surface of the interlayer resin insulating layer by the method described above.
[0184]
Next, the step (d), that is, a solder resist layer forming step for forming a solder resist layer having an opening communicating with the opening formed in the step (c) on one side of the multilayer wiring board is performed.
Specifically, for example, the solder resist layer can be formed by performing the following steps (1) and (2).
[0185]
(1) First, a solder resist composition layer is formed on the outermost layer of the multilayer wiring board in which the optical signal transmission opening is formed.
The layer of the solder resist composition can be formed by, for example, a method similar to the method used in the (c) solder resist layer forming step of the production method of the first invention.
[0186]
(2) Next, an opening communicating with the optical signal transmission opening (hereinafter also referred to as an optical path opening) is formed in the solder resist composition layer.
Specifically, for example, it can be formed by exposure development processing, laser processing, or the like.
Further, when forming the optical path opening, it is desirable to form the solder bump forming opening at the same time. The formation of the optical path opening and the formation of the solder bump forming opening may be performed separately.
Also, when forming the solder resist layer, a solder resist layer having an opening for an optical path and an opening for forming a solder bump is prepared by preparing a resin film having an opening at a desired position in advance and pasting the resin film. May be formed.
[0187]
The cross-sectional diameter of the optical path opening may be smaller than the cross-sectional diameter of the optical signal transmission opening. In this case, the diameter of the cross section of the optical path opening may be 20 to 100 μm smaller than the diameter of the cross section of the optical signal transmission opening.
[0188]
Through the steps (1) and (2), a solder resist layer having an opening communicating with the optical signal transmission opening is formed on the multilayer wiring board in which the optical signal transmission opening is formed. be able to.
[0189]
When the optical signal transmission opening is filled with an uncured resin composition in the opening formation step (c), the optical path opening formed in the solder resist layer is the same as the optical signal transmission opening. The uncured resin composition may be filled by this method. After filling the uncured resin composition into the optical path opening of the solder resist layer in this way, the uncured resin composition is subjected to a curing treatment to thereby form an optical signal transmission optical path composed of the resin composition. Can be formed.
The solder resist layer having an opening communicating with the optical path opening is formed on one side of the multilayer wiring board, that is, on the optical signal transmission opening forming side of the multilayer wiring board. A solder resist layer having no opening may be formed on the surface.
[0190]
In addition, after forming the optical signal transmission opening and the optical path opening, a microlens forming step of forming a microlens in an end portion of the optical signal transmission optical path or in the optical signal transmission optical path as necessary. It is desirable to do. This is because the transmission loss of the optical signal can be further suppressed.
In order to form the microlens in the end of the optical signal transmission optical path or in the optical signal transmission optical path, the same method as described in the method for manufacturing the IC chip mounting substrate of the first aspect of the present invention is used. Can do.
[0191]
In the manufacturing method of the IC chip mounting substrate of the second aspect of the present invention, after performing the steps (a) to (d), for example, using the following method, formation of solder pads and solder bumps, An IC chip mounting substrate can be manufactured by mounting the optical element.
The formation of the solder pads and solder bumps and the mounting of the optical element can be performed by the same method as the manufacturing method of the IC chip mounting substrate of the first invention.
[0192]
In the first and second methods for manufacturing an IC chip mounting substrate according to the present invention, an optical waveguide is formed between the substrate and the interlayer resin insulating layer. However, the formation position of the optical waveguide in the IC chip mounting substrate of the present invention is not limited between the substrate and the interlayer resin insulation layer, and may be between the interlayer resin insulation layers.
The IC chip mounting substrate having such a configuration is, for example, in the manufacturing method of the IC chip mounting substrate of the second aspect of the present invention, without forming an optical waveguide in the step (a), that is, the optical waveguide forming step. In the step (b), that is, in the multilayer wiring board manufacturing step, the interlayer resin insulating layer and the conductor circuit are laminated and formed, and then the optical waveguide is formed.
[0193]
【Example】
Hereinafter, the present invention will be described in more detail.
Example 1
A. Production of resin film
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 , Silicon Added to prepare an epoxy resin composition agent 0.5 parts by weight.
After applying the obtained epoxy resin composition onto a PET film having a thickness of 38 μm using a roll coater so that the thickness after drying becomes 50 μm, the resin film is dried at 80 to 120 ° C. for 10 minutes. Was made.
[0194]
B. Preparation of resin composition for filling through-hole
100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell Co., Ltd., molecular weight: 310, YL983U), 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.
[0195]
C. substrate
As the substrate, an insulating substrate made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 0.8 mm was used.
[0196]
D. Optical waveguide manufacturing
Next, an optical waveguide having an optical path conversion mirror was manufactured using the following method.
That is, a 45 ° optical path conversion mirror is formed on one end of a film-like optical waveguide made of PMMA (manufactured by Microparts: width 1 mm, thickness 20 μm) using a diamond saw with a V-shaped 90 ° tip. Manufactured.
[0197]
E. Manufacture of laminates
(1) A copper-clad resin film in which 18 μm of copper foil 28 is laminated on both surfaces of a base material layer 31 formed by thermosetting the resin film described in A above at 170 ° C. for 30 minutes was used as a starting material (see FIG. 3 (a)). First, the copper-clad resin film was laser drilled, subjected to electroless plating, and etched into a pattern, thereby forming the conductor circuit 24 and the through hole 29 on both surfaces of the base material layer 31.
[0198]
(2) The base material layer 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), NaClO₂(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 reducing bath was performed to form a roughened surface (not shown) on the surface of the conductor circuit 24 including the through holes 29 (see FIG. 3B).
[0199]
(3) After preparing the resin filler described in B above, within 24 hours after preparation by the following method, the conductor circuit non-formed portion on the one side of the through hole 29 and the base material layer 31 and the outer edge of the conductor circuit 24 A layer of a resin filler 30 'was formed on the part.
That is, first, a resin filler was pushed into a through hole using a squeegee, and then dried at 100 ° C. for 20 minutes. Next, a mask having an opening corresponding to the conductor circuit non-forming portion is placed on the base material layer, and the conductor circuit non-forming portion which is a concave portion is filled with a resin filler using a squeegee. A layer of the resin filler 30 ′ was formed by drying at 20 ° C. for 20 minutes (see FIG. 3C).
[0200]
(4) The surface of the conductor circuit 24 and the land of the through hole 29 are formed on one side of the base material layer after the processing in (3) above by belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku). Polishing was performed so that the resin filler 30 'did not remain on the surface, and then buffing was performed to remove scratches caused by the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the base material layer.
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.
[0201]
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. A base material layer in which the inner wall surface of the through hole 29 and the resin filler 30 are firmly adhered to each other via a roughened surface (not shown) was obtained (not shown). (Refer FIG.3 (d)). By this step, the surface of the resin filler layer 30 and the surface of the conductor circuit 24 are flush with each other.
[0202]
(5) The base material layer is washed with water, acid degreased, soft-etched, and then sprayed on both surfaces of the substrate by spraying to etch the surface of the conductor circuit 24 and the land surface of the through hole 29. Thus, a roughened surface (not shown) was formed on the entire surface of the conductor circuit 24. As an etching solution, an etching solution containing 10 parts by weight of imidazole copper (II) complex, 7 parts by weight of glycolic acid, and 5 parts by weight of potassium chloride (MEC Etch Bond, manufactured by MEC) was used.
[0203]
(6) Next, a resin film slightly larger than the base material layer prepared in A is placed on the base material layer, and temporarily press-bonded under conditions of a pressure of 0.4 MPa, a temperature of 80 ° C., and a pressure bonding time of 10 seconds. After 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, the resin film was subjected to main pressure bonding on the base material layer 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.
[0204]
(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 insulating 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).
[0205]
(8) The base material layer in which the via hole opening 26 is formed is immersed in an 80 ° C. solution containing 60 g / l of permanganic acid for 10 minutes to dissolve the epoxy resin particles present on the surface of the interlayer resin insulating layer 22. By removing, a roughened surface (not shown) was formed on the surface including the inner wall surface of the opening 26 for the via hole.
[0206]
(9) Next, the base material layer after the above treatment was immersed in a neutralization solution (manufactured by Shipley Co., Ltd.) and then washed with water.
Furthermore, a catalyst is applied to the surface of the interlayer resin insulating layer 22 (including the inner wall surface of the opening 26 for the via hole) by applying a palladium catalyst to the surface of the roughened substrate layer (roughening depth: 3 μm). Nuclei were attached (not shown). That is, the base material layer 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.
[0207]
(10) Next, the base material layer is immersed in an electroless copper plating aqueous solution having the following composition, and the thickness of the surface of the interlayer resin insulation layer 22 (including the inner wall surface of the via hole opening 26) is 0.6. A thin conductive layer (electroless copper plating film) 32 having a thickness of ˜3.0 μm was formed (see FIG. 4B).
[Electroless plating aqueous solution]
NiSO₄                         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
[0208]
(11) Next, a commercially available photosensitive dry film is pasted on the base material layer on which the thin film conductor layer (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).
[0209]
(12) Next, the base material layer is washed and degreased with water at 50 ° C., washed with water at 25 ° C. and further washed with sulfuric acid, and then subjected to electrolytic plating under the following conditions, thereby forming no plating resist 23 An electrolytic copper plating film 33 having a thickness of 20 μm was formed on the part (see FIG. 4D).
[Electrolytic plating solution]
Sulfuric acid 2.24 mol / l
Copper sulfate 0.26 mol / l
Additive 19.5 ml / l
(Manufactured by Atotech Japan, Kaparaside HL)
[Electrolytic plating conditions]
Current density 1 A / dm²
65 minutes
Temperature 22 ± 2 ° C
[0210]
(13) Further, after removing the plating resist 23 with 5% NaOH, the thin film conductor layer under the plating resist 23 is etched and removed with a mixed solution of sulfuric acid and hydrogen peroxide to remove the thin film conductor layer ( A conductor circuit 25 (including via hole 27) having a thickness of 18 μm made of electroless copper plating film 32 and electrolytic copper plating film 33 was formed (see FIG. 5A).
[0211]
(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 is laminated to form a conductor circuit laminate ( (Refer FIG.5 (b)).
Thereafter, an opening 46 having a diameter of 250 μm that penetrates the base material layer 31 and the interlayer resin insulating layer 22 using a carbon dioxide gas laser through a mask in which a through hole having a thickness of 1.2 mm is formed on the interlayer resin insulating layer 22. Further, desmear treatment was performed on the wall surface of the opening 46 (see FIG. 5C).
[0212]
(15) Next, a catalyst is applied to the wall surface of the opening 46 and the surface of the interlayer resin insulation layer 22 by the same method as used in the step (9), and further used in the step (10). The conductor circuit laminate is immersed in an electroless copper plating aqueous solution similar to the electroless plating solution, and the surface of the interlayer resin insulating layer 22 (including the inner wall surface of the via hole opening 26) and the wall surface of the opening 46 A thin film conductor layer (electroless copper plating film) 32 was formed (see FIG. 6A).
[0213]
(16) Next, a plating resist 23 is provided on a part of the thin film conductor layer by the same method as that used in the step (11), and the same method as that used in the step (12). By this method, an electrolytic copper plating film 33 having a thickness of 20 μm was formed on the portion where the plating resist 23 was not formed (see FIG. 6B).
[0214]
(17) Next, the plating resist 23 is peeled off on a part of the thin film conductor layer and the thin film conductor layer under the plating resist 23 is removed by the same method as used in the step (13). The conductor circuit 25 (including the via hole 27) and the 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)).
[0215]
(18) Next, using a squeegee, the opening 46 in which the conductor layer 45 was formed was filled with a resin composition containing an epoxy resin, dried, and then the surface layer was flattened by buffing. Furthermore, the hardening process was performed and the resin composition layer 42a was formed (refer Fig.7 (a)).
[0216]
(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.
[0217]
(20) Next, the solder resist composition is applied to a thickness of 30 μm on one side of the conductor circuit laminate on which the resin composition layer 42a is formed, and the conditions are 70 ° C. for 20 minutes and 70 ° C. for 30 minutes. A drying process was performed to form a solder resist composition layer 34 ′ (see FIG. 7B).
[0218]
(21) Next, a photomask having a thickness of 5 mm on which patterns of openings for forming solder bumps and openings for optical paths are drawn is brought into close contact with the layer 34 ′ of the solder resist composition on the IC chip mounting side to be 1000 mJ / cm²Were exposed to UV light and developed with DMTG solution to form openings with a diameter of 200 μm.
Further, the solder resist composition layer is cured by heating at 80 ° C. for 1 hour, at 100 ° C. for 1 hour, at 120 ° C. for 1 hour, and at 150 ° C. for 3 hours. The solder resist layer 34 having an optical path opening 42b and a thickness of 20 μm was formed. In addition, as said solder resist composition, a commercially available solder resist composition can also be used.
[0219]
(22) Next, the conductor circuit laminate in 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 47 by immersing in an electroless nickel plating solution having a pH of 4.5 and containing mol / l) for 20 minutes. 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^-1mol / l) is 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 to form a solder pad 36. A body was obtained (see FIG. 8 (a)).
[0220]
F. Lamination process
(1) First, an optical waveguide 50 having an optical path conversion mirror is attached to a predetermined position on the solder resist layer non-formation surface (the lower surface in the figure) of the laminate manufactured in the process E using the following method. (See FIG. 8B).
That is, the optical waveguide manufactured in the above step D was attached to the conductor circuit non-forming portion so that the side surface of the other end on the light conversion mirror non-forming side and the side surface of the interlayer resin insulating layer were 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.
(2) Next, after preparing the resin filler described in B above, within one and a half hours after the preparation by the following method, the one-sided conductor circuit non-formed portion in which the solder resist layer is not formed in the via hole 27 A resin filler layer was formed on the outer edge of the optical waveguide non-forming portion and the conductor circuit 25 (including the via hole 27).
That is, first, a resin filler was pushed into a via hole using a squeegee and then dried under conditions of 100 ° C. for 20 minutes. Next, a mask having an opening corresponding to the conductor circuit and the optical waveguide non-forming portion is placed on the laminate, and the conductive circuit non-forming portion which is a recess is filled with a resin filler using a squeegee. The resin filler layer was formed by drying at 100 ° C. for 20 minutes.
[0221]
(3) One side of the laminate after the treatment of (2) is applied to the surface of the conductor circuit 25 and the surface of the optical waveguide 50 by belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku). Polishing was performed so that the resin filler did not remain, and then buffing was performed to remove scratches due to the belt sander polishing.
Next, heat treatment was performed at 100 ° C. for 1 hour, 120 ° C. for 3 hours, 150 ° C. for 1 hour, and 180 ° C. for 7 hours to form the resin filler layer 51.
[0222]
Thus, the via hole 27, the surface layer portion of the resin filler 51 formed in the conductor circuit and the optical waveguide non-forming portion, the surfaces of the conductor circuit 25 and the optical waveguide 50 are flattened, and the resin filler 51 and the conductor circuit 25 are flattened. Of the via hole 27 and the resin filler 51 are firmly adhered to each other through a roughened surface (not shown). A laminate was obtained (see FIG. 9A). By this step, the surface of the resin filler layer 51 and the surfaces of the conductor circuit 24 and the optical waveguide 50 become the same plane.
[0223]
(4) Next, through the steps (1) to (3), the laminate on which the optical waveguide 50 and the resin filler layer 51 are formed is placed on the C substrate 21, and the vacuum laminator device is And pressure-bonding under vacuum or reduced pressure under the conditions of pressure 0.5 MPa, temperature 100 ° C., time 120 seconds, and then thermally cured at 150 ° C. for 40 minutes to form the optical waveguide 50 and the resin filler layer 51 on the substrate 21. The laminated body in which was formed was laminated.
[0224]
(5) Next, a solder paste is printed in the solder bump forming opening 47 formed in the solder resist layer 34, and further, the light receiving portion 38a and the light emitting portion 39a of the light receiving element 38 and the light emitting element 39 are attached while being aligned. By reflowing at 200 ° C., the light receiving element 38 and the light emitting element 39 were mounted, and the solder bump 37 was formed in the solder bump forming opening 47 to obtain an IC chip mounting substrate (see FIG. 9B). ).
The light receiving element 38 was made of InGaAs, and the light emitting element 39 was made of InGaAsP.
In the IC chip mounting substrate manufactured in this example, the optical path for optical signal transmission is composed of the resin composition, the gap, and the conductor layers around them.
[0225]
(Example 2)
In the step (18) of Example 1, an IC chip mounting substrate was obtained in the same manner as in Example 1 except that a resin composition containing polyolefin was used instead of the resin composition containing epoxy resin.
In the IC chip mounting substrate manufactured in this example, the optical path for optical signal transmission is composed of the resin composition, the gap, and the conductor layers around them.
[0226]
(Example 3)
An IC chip mounting substrate was obtained in the same manner as in Example 1 except that the step (18) of Example 1, that is, the step of forming the resin composition layer 42a was not performed.
In the IC chip mounting substrate manufactured in this example, the optical path for transmitting an optical signal is composed of a gap and a surrounding conductor layer.
[0227]
Example 4
In the steps (15) and (16) of Example 1, an IC chip mounting substrate was obtained in the same manner as in Example 1 except that no conductor layer was formed on the wall surface of the opening.
In the IC chip mounting substrate manufactured in this example, the optical path for optical signal transmission is composed of the resin composition and the gap.
[0228]
(Example 5)
In the steps (15) and (16) of Example 1, no conductor layer is formed on the wall surface of the opening. In the step (18), a resin composition containing polyolefin is used instead of the resin composition containing epoxy resin. An IC chip mounting substrate was obtained in the same manner as in Example 1 except that the product was used.
In the IC chip mounting substrate manufactured in this example, the optical path for optical signal transmission is composed of the resin composition and the gap.
[0229]
(Example 6)
In the steps (15) and (16) of Example 1, the conductor layer was not formed on the wall surface of the opening, and the step (18), that is, the step of forming the resin composition layer 42a was not performed. In the same manner as in Example 1, an IC chip mounting substrate was obtained.
In the IC chip mounting substrate manufactured in this example, the optical path for transmitting an optical signal is constituted by a gap.
[0230]
(Example 7)
(1) A copper clad laminate in which 18 μm copper foil 128 is laminated on both surfaces of an insulating substrate 121 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. 10 (a)). First, the copper-clad laminate was drilled, subjected to electroless plating, and etched into a pattern to form conductor circuits 124 and through holes 129 on both surfaces of the substrate 121.
[0231]
(2) The substrate on which the through hole 129 and the conductor circuit 124 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 124 including the through hole 129.
[0232]
(3) Next, an optical waveguide 150 having an optical path conversion mirror was formed at a predetermined position on the substrate surface using the following method (see FIG. 10B).
That is, a film-shaped optical waveguide made of PMMA in which a 45 ° optical path conversion mirror is formed in advance using a diamond saw having a V-shaped 90 ° at one end (manufactured by Microparts: width 1 mm, thickness 20 μm) ) Was attached so that the side surface of the other end on the light conversion mirror non-formation side and the side surface of the substrate were aligned.
The optical waveguide 150 is attached by applying an adhesive made of a thermosetting resin to the adhesive surface of the optical waveguide with the substrate in a thickness of 10 μm, and curing it at 60 ° C. for 1 hour after pressure bonding. went.
In this example, curing was performed under conditions 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.
[0233]
(4) After preparing the resin filler described in B of Example 1, within 24 hours after preparation by the following method, the conductor circuit non-formation part in one side of the through-hole 129 and the substrate 121 and the optical waveguide non-formation And a layer of a resin filler 130 ′ was formed on the outer edge of the conductor circuit 124. That is, first, a resin filler was pushed into a through hole using a squeegee, and then dried at 100 ° C. for 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 130 'was formed by drying for 20 minutes (see FIG. 10C).
[0234]
(5) One side of the substrate after the processing of (4) above is applied to the surface of the conductor circuit 124 and the land surface of the through hole 129 by belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku). Polishing was performed so as not to leave the resin filler 130 ', 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.
Next, heat treatment was performed at 100 ° C. for 1 hour, 120 ° C. for 3 hours, 150 ° C. for 1 hour, and 180 ° C. for 7 hours to form the resin filler layer 130.
[0235]
In this way, the surface layer portion of the resin filler 130 and the surface of the conductor circuit 124 formed in the through hole 129 and the conductor circuit non-forming portion are flattened, and the resin filler 130 and the side surface of the conductor circuit 124 are roughened. An insulating substrate was obtained in which the inner wall surface of the through hole 129 and the resin filler 130 were firmly adhered via a roughened surface (not shown) (not shown). (Refer FIG.10 (d)). By this step, the surface of the resin filler layer 130, the surface of the conductor circuit 124, and the surface of the optical waveguide 150 become the same plane.
[0236]
(6) After washing the substrate with water and acid degreasing, soft etching is performed, and then an etching solution is sprayed on both surfaces of the substrate to spray the surface of the conductor circuit 124, the land surface of the through hole 129, and the inner wall. Thus, a roughened surface (not shown) was formed on the entire surface of the conductor circuit 124. 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.
[0237]
(7) Next, a resin film slightly larger than the substrate prepared in the above (1) was placed on the substrate and cut by temporary pressure bonding under conditions of a pressure of 0.4 MPa, a temperature of 80 ° C., and a pressure bonding time of 10 seconds. Thereafter, the interlayer resin insulating layer 122 was further formed by pasting using a vacuum laminator apparatus by the following method (see FIG. 10E).
That is, the resin film was subjected to final pressure bonding on the substrate under the conditions of a degree of vacuum of 65 Pa, a pressure of 0.4 MPa, a temperature of 80 ° C., and a time of 60 seconds, and then thermally cured at 170 ° C. for 30 minutes. The resin film was produced in the same manner as A in Example 1.
[0238]
(8) 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 122.₂With a gas laser, a via hole opening with a diameter of 80 μm is formed in the interlayer resin insulating layer 122 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. 126 was formed (see FIG. 11A).
[0239]
(9) The substrate on which the via hole opening 126 is formed is dipped 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 122. As a result, a roughened surface (not shown) was formed on the surface including the inner wall surface of the opening 126 for the via hole.
[0240]
(10) 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), catalyst nuclei are formed on the surface of the interlayer resin insulating layer 122 (including the inner wall surface of the via hole opening 126). 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.
[0241]
(11) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition, and a thickness of 0.6 to 3 is formed on the surface of the interlayer resin insulation layer 122 (including the inner wall surface of the via hole opening 126). A thin film conductor layer (electroless copper plating film) 132 having a thickness of 0.0 μm was formed (see FIG. 11B).
[Electroless plating aqueous solution]
NiSO₄                         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
[0242]
(12) Next, a commercially available photosensitive dry film is attached to the substrate on which the thin film conductor layer (electroless copper plating film) 132 is formed, and a mask is placed thereon, and 100 mJ / cm.²Then, a plating resist 123 having a thickness of 20 μm was provided by developing with a 0.8% aqueous sodium carbonate solution (see FIG. 11C).
[0243]
(13) 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 123 non-formed portion. Then, an electrolytic copper plating film 133 having a thickness of 20 μm was formed (see FIG. 11D).
[Electrolytic plating solution]
Sulfuric acid 2.24 mol / l
Copper sulfate 0.26 mol / l
Additive 19.5 ml / l
(Manufactured by Atotech Japan, Kaparaside HL)
[Electrolytic plating conditions]
Current density 1 A / dm²
65 minutes
Temperature 22 ± 2 ° C
[0244]
(14) Further, after removing the plating resist 123 with 5% NaOH, the thin film conductor layer under the plating resist 123 is etched and removed with a mixed solution of sulfuric acid and hydrogen peroxide to remove the thin film conductor layer ( A conductor circuit 125 (including via holes 127) having a thickness of 18 μm formed of an electroless copper plating film 132 and an electrolytic copper plating film 133 was formed (see FIG. 12A).
[0245]
(15) Further, a roughened surface (not shown) is formed on the surface of the conductor circuit 125 using the same etching solution as the etching solution used in the step (6). In the same manner as in the step (8), an interlayer resin insulating layer 122 having a via hole opening 126 and having a roughened surface (not shown) formed on the surface thereof was laminated (see FIG. 12B). .
Thereafter, an opening 146 having a diameter of 250 μm is formed at a position facing the optical waveguide 150 of the interlayer resin insulating layer 122 using a carbon dioxide gas laser through a mask in which a through hole having a thickness of 1.2 mm is formed. A desmear process was performed on the wall surface of the opening 146 (see FIG. 12C).
[0246]
(16) Next, a catalyst is applied to the surface of the interlayer resin insulation layer 122 by the same method as used in the step (10), and the electroless plating solution used in the step (11). The substrate was immersed in the same electroless copper plating aqueous solution as in Example 1, and a thin film conductor layer (electroless copper plating film) 132 was formed on the surface of the interlayer resin insulation layer 122 (including the inner wall surface of the via hole opening 126). (See FIG. 13 (a)). In addition, the mask was formed in the wall surface of the opening formed at the said process, and the catalyst was not provided.
[0247]
(17) Next, a plating resist 123 is provided by a method similar to the method used in the step (12), and further, the plating resist 123 is not coated by a method similar to the method used in the step (13). An electrolytic copper plating film 133 having a thickness of 20 μm was formed on the formation part (see FIG. 13B).
[0248]
(18) Next, the plating resist 123 is peeled off and the thin film conductor layer under the plating resist 123 is removed by a method similar to the method used in the step (14), and the conductor circuit 125 (via hole 127) is removed. Formed).
Further, oxidation / reduction treatment was performed in the same manner as the method used in the step (2), so that the surface of the conductor circuit 125 was a roughened surface (not shown) (see FIG. 13C).
[0249]
(19) Next, using a squeegee, the opening 146 was filled with a resin composition containing an epoxy resin, dried, and then planarized by buffing. Furthermore, the hardening process was performed and the resin composition layer 142a was formed (refer Fig.14 (a)).
[0250]
(20) Next, the photosensitizing property 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.
[0251]
(21) Next, the solder resist composition is applied to both sides of the substrate on which the resin composition layer 142a is formed in a thickness of 30 μm, and dried under conditions of 70 ° C. for 20 minutes and 70 ° C. for 30 minutes. To form a layer 134 'of the solder resist composition. (See FIG. 14 (b)).
[0252]
(22) Next, a photomask having a thickness of 5 mm on which patterns of openings for forming solder bumps and openings for optical paths are drawn is brought into close contact with the layer 134 ′ of the solder resist composition on the IC chip mounting side to be 1000 mJ / cm²Were exposed to UV light and developed with DMTG solution to form openings with a diameter of 200 μm.
Further, the solder resist composition layer is cured by heat treatment 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, and the solder bump forming openings 147 are formed. A solder resist layer 134 having an optical path opening 142b and a thickness of 20 μm was formed (see FIG. 15A).
[0253]
(23) Next, the substrate on which the solder resist layer 134 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 147 by immersing in an electroless nickel plating solution having a pH of 4.5 and containing mol / l) for 20 minutes. 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) containing an electroless gold plating solution was immersed for 7.5 minutes at 80 ° C. to form a 0.03 μm-thick gold plating layer on the nickel plating layer, thereby forming a solder pad 136.
[0254]
(24) Next, solder paste is printed in the solder bump forming opening 147 formed in the solder resist layer 134, and further, the light receiving portion 138a and the light receiving portion 139a of the light emitting device 139 are aligned while being aligned. By reflowing at 200 ° C., the light receiving element 138 and the light emitting element 139 were mounted, and the solder bump 137 was formed in the solder bump forming opening 147 to obtain an IC chip mounting substrate (see FIG. 15B). ).
The light receiving element 138 was made of InGaAs, and the light emitting element 139 was made of InGaAsP.
In the IC chip mounting substrate manufactured in this example, the optical path for optical signal transmission is composed of the resin composition, the gap, and the conductor layers around them.
[0255]
(Example 8)
In the process of Example 7 (3), instead of the method of forming the optical waveguide by attaching a film-shaped optical waveguide, the following method was used, except that the optical waveguide was directly formed on the substrate. In the same manner as in Example 7, an IC chip mounting substrate was obtained.
That is, a resin composition containing a PMMA resin is applied to a predetermined position on a substrate, dried, and then the surface layer is flattened by buffing. Further, after curing, the tip has a V-shaped 90 ° at one end. A 45 ° optical path conversion mirror was formed using a diamond saw to form an optical waveguide.
[0256]
(Reference example)
(1) First, the same steps as (1) to (19) of Example 7 were performed to produce a multilayer wiring board in which an optical waveguide and an optical signal transmission opening were formed.
Next, the light receiving element and the light emitting element were attached to the end of the optical signal transmission opening filled with the resin composition while being aligned. The light receiving element was made of InGaAs, and the light emitting element was made of InGaAsP. The connection between the light receiving element and the connection terminal of the light emitting element and the conductor circuit of the multilayer wiring board was made with a conductive adhesive.
[0257]
(2) Next, on the multilayer wiring board to which the light receiving element and the light emitting element are attached, the interlayer resin insulating layer and the conductor circuit are formed by the same method as that used in the steps (7) to (14) of Example 7. Formed.
Here, as the resin film, a film in which openings are provided in advance corresponding to the light receiving element and the light emitting element was used.
Furthermore, the conductor circuit and the solder resist layer were formed by performing the same method as the method used in the steps (16) to (24) of Example 7. Here, the step (19) was not performed, and the conductor circuit was formed to be connected to the optical element.
Using such a method, an IC chip mounting substrate having an optical element (light receiving element and light emitting element) mounted therein was manufactured.
[0258]
100 IC chip mounting substrates are manufactured by the methods shown in Examples 1 to 8 and the reference example, and these IC chip mounting substrates are cut with a blade so as to pass through the optical waveguide and the optical path for optical signal transmission. The cross section was observed.
As a result, in any of the IC chip mounting substrates, an optical waveguide and an optical path for transmitting an optical signal that connects the optical waveguide and the optical element are secured.
[0259]
Further, 100 IC chip mounting substrates are manufactured by the methods shown in Examples 1 and 7 and the reference example, respectively, and the optical chip is output after these IC chip mounting substrates are mounted on the IC chips. A detector is attached to the end of the optical waveguide, and then the optical signal is sent through the optical waveguide on the side where the optical signal is input. After being calculated by the IC chip, the optical signal is detected by the detector and received. The connection loss between the device and the light emitting device and the optical path for optical signal transmission was measured.
[0260]
As a result, 5 out of 100 IC chip mounting substrates manufactured by the method shown in Example 1 and 7 out of 100 IC chip mounting substrates manufactured by the method shown in Example 7. In the IC chip mounting substrate, it was found that a desired optical signal could not be detected and the connection loss was large.
Further, in the IC chip mounting substrate manufactured by the method shown in the reference example, a desired optical signal cannot be detected and 40% of the 100 IC chip mounting substrates have a large connection loss. It's been found.
The number of poorly connected products on the IC chip mounting board manufactured by the method shown in the reference example is that, in the method shown in the reference example, after the optical element is mounted, the conductor circuit and the interlayer resin insulation layer In this process, it is necessary to perform a heat treatment or the like, and it was estimated that the optical element was displaced during the heat treatment and a connection failure occurred.
[0261]
In addition, even in the IC chip mounting substrate manufactured by the method shown in Examples 1 and 7, there was a product in which connection failure occurred due to the displacement of the optical element, but the optical element was surface-mounted. Therefore, such a connection failure could be solved by replacing only the optical element.
[0262]
In addition, in the IC chip mounting substrate manufactured by the method shown in Examples 1 and 7, a microlens is formed at the end of the optical path for optical signal transmission via an adhesive layer. In the IC chip mounting substrate manufactured by the method shown, a microlens was formed by dropping acrylic resin on the resin composition inside the optical path for optical signal transmission using a dispenser (FIGS. 2 and 2). 16).
Then, the connection loss of the optical signal of the IC chip mounting substrate on which these microlenses were formed was measured in the same manner as the above method, and both were measured on the IC chip mounting substrate manufactured by the method shown in Examples 1 and 7. In comparison, a desired optical signal could not be detected and the number of IC chip mounting substrates with large connection loss was small.
[0263]
【The invention's effect】
In the IC chip mounting substrate of the present invention, as described above, an optical waveguide is formed inside the IC chip mounting substrate, and an optical signal transmission optical path for connecting the optical element and the optical waveguide is disposed. Therefore, the input / output signal of the optical element can be transmitted through the optical waveguide and the optical path for optical signal transmission. Further, when the IC chip is mounted on the substrate, the distance between the IC chip and the optical element is short, and the reliability of electric signal transmission is excellent.
Moreover, the IC chip mounting substrate of the present invention on which the IC chip is mounted can contribute to the miniaturization of the optical communication terminal device because the electronic components and optical elements necessary for optical communication can be integrated. .
[0264]
In addition, in the IC chip mounting substrate of the present invention, when the optical element is surface-mounted, there is no displacement due to heat treatment during manufacturing, and in addition, there is a problem with one optical element. In this case, only the optical element needs to be replaced, which is economically advantageous.
[0265]
In the IC chip mounting substrate manufacturing method of the first and second aspects of the present invention, an optical waveguide is formed inside the IC chip mounting substrate, and an opening communicating with the conductor circuit laminate and the solder resist layer is formed. . This communicating opening can play a role as an optical path for optical signal transmission. Therefore, the IC chip mounting substrate manufactured by the manufacturing method of the IC chip mounting substrate of the first and second inventions is optical When the element is mounted, the optical signal can be suitably transmitted between the optical element and the optical waveguide through the optical signal transmission optical path.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an embodiment of an IC chip mounting substrate of the present invention.
FIG. 2 is a cross-sectional view schematically showing another embodiment of an IC chip mounting substrate of the present invention.
FIG. 3 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate of the first invention.
FIG. 4 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate according to the first aspect of the present invention;
FIG. 5 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate of the first invention.
FIG. 6 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate according to the first aspect of the present invention.
FIG. 7 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate according to the first aspect of the present invention;
FIG. 8 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate according to the first aspect of the present invention;
FIG. 9 is a cross-sectional view schematically showing part of the method of manufacturing the IC chip mounting substrate according to the first aspect of the present invention.
FIG. 10 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate of the second invention.
FIG. 11 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate of the second invention.
FIG. 12 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate of the second invention.
FIG. 13 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate of the second invention.
FIG. 14 is a cross-sectional view schematically showing a part of the manufacturing method of the IC chip mounting substrate of the second invention.
FIG. 15 is a cross-sectional view schematically showing part of the method of manufacturing the IC chip mounting substrate according to the second aspect of the present invention.
FIG. 16 is a cross-sectional view schematically showing another embodiment of an IC chip mounting substrate of the present invention.
[Explanation of symbols]
20, 120, 220, 320 IC chip mounting substrate
21, 121, 221, 321 substrate
22, 122, 222, 322 Interlayer resin insulation layer
24, 124, 224, 324 Conductor circuit
27, 127, 227, 327 Via hole
29, 129, 229, 329 Through hole
31 Base material layer
34, 134, 234, 334 Solder resist layer
38, 138, 238, 338 Light receiving element
39, 139, 239, 339 Light emitting element
240, 340 IC chip
242 and 342 Optical path for optical signal transmission
45, 245, 345 Conductor layer
50, 150, 250, 350 Optical waveguide

Claims (4)

An IC chip mounting substrate in which a conductor circuit and an interlayer resin insulation layer are formed on both sides of a substrate, a solder resist layer is formed on the outermost layer, and a light receiving element and a light emitting element are mounted.
A plurality of solder connection portions are formed in the outermost conductor circuit, and a light receiving element, a light emitting element, and an IC chip are mounted through the solder connection portions.
On the surface of the substrate on which the light receiving element and the light emitting element are mounted, an organic optical waveguide having an optical path conversion mirror at the tip is formed,
An optical path for transmitting an optical signal is formed across the conductor circuit and the interlayer resin insulating layer so that the light receiving element, the light emitting element, and the optical waveguide can transmit an optical signal through the optical path conversion mirror.
The optical signal transmission optical path has a region made of a resin composition, a conductor layer is formed around the optical signal transmission optical path, and an end of the optical signal transmission optical path on the light receiving element or light emitting element side Has a microlens disposed thereon , an IC chip mounting substrate. 2. The IC chip mounting substrate according to claim 1, wherein a diameter of a cross section of the optical path for transmitting an optical signal is 100 to 500 μm. 3. The IC chip mounting device according to claim 1 , wherein conductor circuits sandwiching the substrate are connected via through holes, and conductor circuits sandwiching the interlayer resin insulation layer are connected via via holes. substrate. The IC chip mounting according to any one of claims 1 to 3, wherein the resin composition or the organic optical waveguide formed in the optical path for transmitting an optical signal includes particles having a particle diameter shorter than a communication wavelength of light. Substrate .

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