JP2000347051A - Optical/electrical wiring board, its manufacturing method and package board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical/electrical wiring board which is capable of high-density mounting or miniaturization and which enables the mounting of optical parts to be performed in the same method as that of electrical parts. SOLUTION: The device is an optical/electrical wiring board having an optical wiring layer 13, which is provided with a core 1 for propagating light and with a clad 2 for burying the core 1, on the electrical wiring 10 of a wiring base plate 9; it is equipped with a mirror 3 installed in a part of the core 1, a pad 5 installed for the purpose of soldering optical components on the periphery immediately above the mirror 3, and a via hole 12 for electrically connecting the pad 5 to the electrical wiring of the base plate 9. For aligning at the time of the manufacturing, it is desirable to use an alignment mark 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical / electrical wiring board in which optical wiring and electric wiring are mixed, a method of manufacturing the same, and an optical component such as an optical element and an electric component such as an electric element mounted on the substrate. Related to a mounting board.

[0002]

2. Description of the Related Art Recently, semiconductor large-scale integrated circuits (LSIs)
In such electric elements, the degree of integration of transistors is increasing, and the operation speed of the transistors reaches 1 GHz in clock frequency.

In order to mount the highly integrated electric element on an electric wiring board, a BGA (Ball Grid A) is used.
rray) and CSP (Chip Size Packa)
Ge) etc. have been developed and put into practical use.
FIG. 11 schematically shows a structure in which an electric element is mounted on a BGA package and mounted on an electric wiring board.

A so-called build-up multilayer laminate 152 in which insulating layers and conductor layers are alternately laminated on a copper-clad substrate impregnated with an epoxy resin or the like in a glass cloth has bumps 153 formed on one surface of the laminate 152 made of gold or the like. The electrode of the element 151 is electrically connected. A pad 157, which is surface-treated with gold or the like, is formed on the opposite surface, and is connected to the electric wiring board 155 via solder balls 154 by soldering. Electric signals are exchanged with peripheral electric elements (not shown) via electric wiring 156.

There is a demand that as the clock frequency inside the electric element increases, the signal speed between elements outside the electric element also increases. However, when a high-speed signal flows through the electric wiring between the elements, noise such as reflection due to a defective shape of the electric wiring or the influence of crosstalk cannot be avoided. In addition, there is also a problem that electromagnetic waves are generated from the electric wiring and adversely affect the surroundings. For this reason, at present, the signal speed between the electric elements is bothersomely reduced, and the system is constructed so that these problems do not occur. In this case, the function of the highly integrated electric element is not sufficiently utilized.

In order to solve such a problem, it has been considered to replace a part of the electric wiring made of copper on the electric wiring board with an optical wiring made of an optical fiber and use an optical signal instead of an electric signal. This is because, in the case of an optical signal, generation of noise and electromagnetic waves can be suppressed.

In a system in which an electric signal is replaced with an optical signal, the electric signal passes through the electric wiring of the BGA package from the electric element, further passes through the electric wiring on the substrate, and is transmitted by the optical element installed on the substrate. And transmitted to the optical fiber on the same substrate. That is, as shown in FIG. 12, a light emitting element such as a laser or an optical element 166 which is a light receiving element such as a photodiode is arranged around the BGA package 162. In some cases, a driver IC exists between the BGA package and the optical device.

An optical / electrical wiring board in which a part of the copper wiring on the electric wiring board is replaced by an optical wiring using an optical fiber,
In general, as described in "Yamaguchi et al.," Study of Optical Bus Densification Using Fiber Board ", IEICE Electronics Society Conference, C-3-49, 1997," In many cases, optical fibers are arranged in the peripheral area, or optical fibers are arranged in a free state in the upper space of the electric wiring board. Is making it difficult.

In order to solve this problem, Japanese Patent Laid-Open Publication No.
As described in Japanese Patent Application Laid-Open No. 905 and Japanese Patent Application Laid-Open No. 5-281429, a substrate (optical / electrical wiring substrate) in which an optical fiber is fixed on an electric wiring substrate with an insulating film has been proposed.

In such an optical / electrical wiring board, it is difficult to optically match the optical axis of an optical element 166 such as a laser diode or a photodiode with the optical axis of an optical fiber 167 which is an optical wiring. I couldn't agree without relying on others. Therefore, as compared with an electric component such as a BGA package that can be automatically soldered in a reflow furnace or the like, mounting an optical element on an optical / electrical wiring board has a disadvantage that it is very expensive.

Further, when an optical fiber is used as the optical wiring, it cannot cope with an optical wiring having a complicated shape due to the limit of its flexibility, and the degree of freedom of design is reduced. There was a problem that it could not cope with.

For this reason, several configurations of an optical / electrical wiring board using an optical waveguide as an optical wiring on an electric wiring board have been proposed. For example, Japanese Unexamined Patent Publication No.
No. 4 and JP-A-6-258544. In the configuration of the optical waveguide, a core through which an optical signal propagates is embedded in a clad layer that confine the optical signal to the core. The method of forming the core pattern is to form a metal mask by photolithography technology and produce it by dry etching or, if the core material is given photosensitivity, exposure,
It can be produced by development processing. For this reason, since the optical wiring can be formed based on the pattern of the photomask, the degree of freedom of the design is increased. Also, transmission over a relatively short distance can be supported.

However, even in an optical / electrical wiring board using an optical waveguide as an optical wiring, it is very difficult to align the optical axis as in the case where an optical fiber is used. The above-mentioned JP-A-4-146684 and JP-A-6-258
In Japanese Patent Application Publication No. 544, there is no description about the structure of optical axis alignment between an optical element such as a laser diode or a photodiode and an optical waveguide.

In Japanese Patent Application Laid-Open No. 6-69490,
Similarly, an optical / electrical wiring board using an optical waveguide as the optical wiring is described. However, since the connection between the optical element and the optical waveguide uses an optical fiber, the optical axis alignment becomes very difficult similarly.

On the other hand, as a method of forming an optical waveguide on an electric wiring board, Japanese Patent Application Laid-Open No. Hei 9-236731 discloses a method of directly building up and forming a ceramic multilayer wiring board on a ceramic multilayer wiring board. There has been proposed a method in which a clad layer is formed on a substrate, a core pattern is formed, and the core pattern is further covered with the clad layer.

However, very large irregularities are formed on the surface of the electric wiring board as a base of the optical wiring layer due to the multilayered electric wiring. For this reason, if the optical waveguide is formed directly on the surface, there is a problem that the propagation loss of the optical signal increases due to the unevenness.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and is capable of high-density mounting or miniaturization, and in which optical components are mounted in the same manner as electrical components. It is an object of the present invention to provide an optical / electrical wiring board which can be realized by the above.

[0018]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, a core for transmitting light and a core for propagating light on electric wiring of a substrate having electric wiring are provided. An optical / electrical wiring board including an optical wiring layer having a buried cladding, a mirror provided on a part of a core, and a pad provided for soldering an optical component immediately above the mirror. And a via hole for electrically connecting the pad and the electric wiring of the substrate.

According to the second aspect of the present invention, there is provided an optical / electrical wiring board including an optical wiring layer having a core for transmitting light and a clad for burying the core, on the electric wiring of the substrate having the electric wiring. A mirror provided on a part of the core, a pad for the optical component provided for soldering the optical component immediately above the mirror, and an optical wiring layer for soldering the electrical component. An optical / electrical wiring board, comprising: a provided pad for an electrical component; and a via hole for electrically connecting the optical component or the pad for the electrical component to an electrical wiring of the substrate.

According to a third aspect of the present invention, there is provided an optical / electrical wiring board including an optical wiring layer having a core for transmitting light and a clad for burying the core, on the electric wiring of the substrate having the electric wiring. A mirror provided on a part of the core, a pad for the optical component provided for soldering the optical component immediately above the mirror, and an optical wiring layer for soldering the electrical component. It is characterized by comprising a provided electric component pad, an optical component or a via hole for electrically connecting the electric component pad and an electric wiring of the substrate, and an electric wiring provided on the optical wiring layer. Optical and electric wiring boards.

According to the present invention, a resin layer having the same refractive index as the clad is formed on the surface of the optical wiring layer, and a hole is formed on a pad provided for soldering the optical component and the electrical component. 4. The optical / electrical wiring board according to claim 1, wherein said pad surface is exposed.

According to a fifth aspect of the present invention, there is provided a step of forming an optical wiring layer having a positioning alignment mark, a core for transmitting light, and a cladding for burying the alignment mark and the core on a support, Bonding the optical wiring layer to a substrate having electrical wiring by providing a mirror on a part of the core based on the reference, and connecting the electrical wiring on the substrate to the electrical wiring with via holes using the alignment mark as a reference. Forming a core and an alignment mark at the same time, comprising the steps of: forming a core and an alignment mark simultaneously on the optical / wiring layer. .

According to a sixth aspect of the present invention, there is provided a method of forming an optical wiring layer on a support having an alignment mark for positioning, a core for transmitting light, and a cladding for burying the alignment mark and the core, Bonding the optical wiring layer to a substrate having electrical wiring by providing a mirror on a part of the core based on the reference, and connecting the electrical wiring on the substrate to the electrical wiring with via holes using the alignment mark as a reference. Forming a resin layer equal to the refractive index of the clad on the surface of the optical wiring layer, and forming a hole with reference to the alignment mark. , And a core and an alignment mark are formed at the same time.

According to a seventh aspect of the present invention, there is provided a mounting board characterized by mounting an optical component and / or an electrical component on the optical / electrical wiring board according to any one of the first to fourth aspects. is there.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Optical / Electric Wiring Board In the optical / electrical wiring board of the present invention, an optical component (optical element)
1 and 2 show a top view of a portion on which is mounted. Also,
3 and 4 are sectional views taken along the core 1. FIG. The optical wiring layer 13 includes a core 1 through which an optical signal propagates and a clad 2 that confine the optical signal to the core. By making the refractive index of the material forming the core higher than that of the cladding, the optical signal propagates in the core.

The optical wiring layer 13 is fixed to the substrate 9 having the electric wiring 10 via the adhesive 11. Further, on the surface of the optical wiring layer 13, pads 5 and lands 6 for electrically connecting with the optical component and electric wiring 7 for connecting the pads 5 and the lands 6 are provided. The electrical wiring 10 is electrically connected via the via hole 12. Although not shown, the electric connection between the electric component and the electric wiring on the substrate is similarly performed.

The substrate 9 may be a single-layer insulating substrate or a multilayer electric wiring substrate. As a substrate material, a substrate in which a polyimide film or a glass cloth is impregnated with an epoxy resin or the like can be used. Alternatively, a ceramic substrate may be used.

A 45 ° mirror 3 is provided on the core 1 of the optical wiring layer 13. An optical signal is propagated between the optical waveguide and an optical component such as a laser diode or a photodiode via the mirror 3. The mirror surface interface may be brought into contact with a resin having a lower refractive index than the core, or may be brought into contact with air. Further, a metal thin film may be formed.

In FIG. 1, a pad 5 for electrical connection with an optical component is arranged at a peripheral portion immediately above a mirror 3 provided on the core 1. The number of pads need not be limited to four, but may be any number. Further, the shape need not be limited to a circle, but may be any shape. A shape suitable for a solder ball, a metal lead, or the like for connection with an optical component can be selected.

In FIG. 1, an alignment mark 4 for determining the position of the pad 5 and an alignment mark 8 for determining the position of the mirror 3 are formed. These alignment marks are formed simultaneously with the core 1. On the other hand, FIG. 2 shows an example in which the alignment mark 8 is not formed.

3A and 3B, the optical wiring layer 13
Is a cross-sectional view in which pads 5, lands 6 and electric wires 7 are exposed on the surface of FIG. The mirror 3 can be formed in a structure as shown in FIGS.

4A and 4B, the optical wiring layer 13
Are covered with a resin layer 14 having the same refractive index as that of the cladding 2, and only the pad 5 for electrical connection with the optical component is exposed. Further, although not shown, pads for electrically connecting to the electric components also need to be exposed.

2. Method for Manufacturing Optical / Electrical Wiring Board The method for manufacturing an optical / electrical wiring board of the present invention is basically
It is as follows. First, an optical wiring layer is formed on a support separately from a substrate having electric wiring. At this time, the core and the alignment mark are simultaneously formed by photolithography. Next, based on the alignment mark,
A mirror is provided in a part of the core, and the optical wiring layer is bonded to the substrate. Further, a pad electrically connected to the electric wiring on the substrate by the via hole is formed on the optical wiring layer with reference to the alignment mark.

In this manufacturing method, the optical wiring is not directly formed on the insulating substrate having the uneven electric wiring, but is formed on another support in advance and attached to the electric wiring substrate. . As a result, the unevenness of the underlying electric wiring board is reduced, and the loss of the optical signal due to the unevenness is reduced to some extent.
Can be reduced.

Hereinafter, two embodiments will be described.

<First Embodiment of Method of Manufacturing Optical / Electrical Wiring Board> As a first embodiment of a method of manufacturing an optical / electrical wiring board, the optical / electrical wiring board shown in FIG. The description will be made in accordance with the flow of FIGS.

As shown in FIG. 5A, the first support 21
As a release layer 22 on a silicon wafer
A thin film layer of r and Cu was sputtered, and then a Cu layer was formed to about 10 μm in a copper sulfate plating bath.

As shown in FIG. 5B, a polyimide OPI-N1 is formed on the release layer 22 as a first clad 23.
005 (manufactured by Hitachi Chemical Co., Ltd.)
It was imidized at 50 ° C. At this time, the film thickness was 20 μm.

As shown in FIG. 5C, the first clad 2
Polyimide OPI-N1305 as core 24 on 3
(Manufactured by Hitachi Chemical Co., Ltd.) and spin-coated
It was imidized at ℃. At this time, the film thickness was 8 μm.
The core and cladding materials used for this optical wiring layer are not limited to polyimide resins, but can be selected from polymer materials such as fluorinated or deuterated epoxy resins and methacrylate resins, depending on the wavelength of light used for optical signals. Materials with low loss can be selected.

Further, Al was vapor-deposited on the surface of the core layer, a predetermined pattern of a photoresist was formed, and etching was performed to form Al metal masks 25 and 26.
The metal mask 25 indicates a core pattern to be an optical wiring, and the metal mask 26 indicates an alignment mark pattern.

As shown in FIG. 5D, using oxygen gas,
The core 24 was etched by reactive ion etching. Further, the Al film serving as the metal mask was removed by etching to form a core (optical wiring) pattern 27 and an alignment mark pattern 28 at the same time. At this time, the line width of the core pattern was 8 μm, the sectional shape was 8 μm in height,
It became a square having a width of 8 μm. The size of the cross section is not limited to this, and may vary depending on the transmission mode and the refractive index difference between the core and the clad.
It can be selected from μm to 100 μm.

As shown in FIG. 5E, the second clad 2
As No. 9, OPI-1005 is similarly coated and imidized. The cladding thickness at this time is 20 on the core optical wiring layer.
μm.

As shown in FIG. 5F, the second clad 29
Was sputtered with a metal thin film layer of Cr and Cu, and a Cu layer was formed to a thickness of about 10 μm in a copper sulfate plating bath. Further, a pattern of a photoresist was formed by a photolithography technique, and etching was performed with an etching solution to form a pad 30, an electric wiring, and a land. An opening 31 for forming a hole for forming a via hole with a laser later was previously provided in the land. Although not shown, pads, electrical wiring, and lands for electrical component connection were also formed at the same time.

As shown in FIG. 5 (g), a photoresist 32 was coated as a protective film in order to protect the pad 30, the electric wiring and the land made of copper from the stripping solution.

As shown in FIG. 5 (h), the Cu layer in the release layer 22 was dissolved using a ferric chloride solution as a release liquid, and the optical wiring layer was peeled off to produce an optical wiring film.

As shown in FIG. 5 (i), the side on which the pads, electrical wiring and lands on the optical wiring layer are formed is adhered to the second support 33 with an adhesive. The second support 33 is provided with the alignment mark 2 from the side where the light distribution layer is not bonded.
Use a transparent one so that 8 can be seen. Further, as the adhesive, an adhesive which is easily peeled off or an adhesive whose adhesive strength is reduced by curing with ultraviolet rays is used.

As shown in FIG. 5 (j), the core pattern 27
A mirror 34 was formed on a part of the core pattern 27 at an angle of 45 ° with respect to the substrate by machining a part of the core pattern 27 with reference to an alignment mark (not shown) formed at the same time when the pattern was formed.

As shown in FIG. 5 (k), a modified polyimide resin 37 exhibiting thermoplasticity is coated on the substrate 35 having the electric wiring 36 by 20 μm as an adhesive and dried.
The mirror-processed surface of the optical wiring layer was bonded and heated and bonded.

As shown in FIG. 5 (l), the second support 33 was peeled off by irradiating ultraviolet rays.

As shown in FIG. 5M, a plating resist 38 was coated as a protective film on the optical wiring layer.

As shown in FIG. 5 (n), a hole 39 for a via hole was formed in the opening 31 of the land as a position for forming the via hole by using a laser. An excimer laser, a carbon dioxide laser, a YAG laser, or the like is suitable as the laser.

As shown in FIG. 5 (o), the surface of the optical wiring layer and the inside of the laser-processed hole were sputtered with Cr,
A metal thin film of Cu is formed, and this metal thin film is used as an electrode,
Copper plating was performed on the inside and the land of the via hole in a copper sulfate bath. Further, the plating resist 38 serving as a protective film was removed, and a via hole 40 and a land 41 were formed. Thus, the optical / electrical wiring board according to the first embodiment of the present invention was obtained.

<Second Embodiment of Method for Manufacturing Optical / Electrical Wiring Board> As a second embodiment of the method for manufacturing an optical / electrical wiring board, the optical / electrical wiring board shown in FIG. The description will be made in accordance with the flow of FIGS.

As shown in FIG. 6A, a release layer 52 of Cr, Cu
Then, a Cu layer was formed to a thickness of about 10 μm in a copper sulfate plating bath.

As shown in FIG. 6B, a polyimide OPI-N1 is formed on the release layer 52 as a first clad 53.
005 (manufactured by Hitachi Chemical Co., Ltd.)
It was imidized at 50 ° C. At this time, the film thickness was 20 μm.

As shown in FIG. 6C, the first clad 5
3. Polyimide OPI-N1305 as core 54 on 3
(Manufactured by Hitachi Chemical Co., Ltd.) and spin-coated
It was imidized at ℃. At this time, the film thickness was 8 μm.
The core and cladding materials used for this optical wiring layer are not limited to polyimide resins, but can be selected from polymer materials such as fluorinated or deuterated epoxy resins and methacrylate resins, depending on the wavelength of light used for optical signals. Materials with low loss can be selected.

Further, Al was vapor-deposited on the surface of the core layer, a predetermined pattern of photoresist was formed, and an etching process was performed to form Al metal masks 55 and 56.
The metal mask 55 indicates a core pattern to be an optical wiring, and the metal mask 56 indicates an alignment mark pattern.

As shown in FIG. 6D, using oxygen gas,
The core 54 was etched by reactive ion etching. Further, the Al film serving as a metal mask was removed by etching to form a core (optical wiring) pattern 57 and an alignment mark pattern 58 at the same time. At this time, the line width of the core pattern was 8 μm, the sectional shape was 8 μm in height,
It became a square having a width of 8 μm. The size of the cross section is not limited to this, and may vary depending on the transmission mode and the refractive index difference between the core and the clad.
It can be selected from μm to 100 μm.

As shown in FIG. 6E, the second clad 5
As No. 9, OPI-1005 is similarly coated and imidized. The cladding thickness at this time is 20 on the core optical wiring layer.
μm.

As shown in FIG. 6F, the core pattern 57
A mirror 60 was formed on a part of the core pattern 57 at an angle of 45 ° with respect to the substrate by machining on a part of the alignment mark (not shown) formed at the same time when the substrate was formed.

As shown in FIG. 6 (g), the Cu layer in the release layer was dissolved using a ferric chloride solution as the release liquid, and the optical wiring layer was peeled off to produce an optical wiring film.

As shown in FIG. 6 (h), a modified polyimide resin 63 exhibiting thermoplasticity is coated on the substrate 61 having the electric wiring 62 as an adhesive by 20 μm and dried.
The mirror-processed surface of the optical wiring layer was bonded and heated and bonded.

As shown in FIG. 6I, holes 64 for via holes were formed at positions where via holes were to be formed using a laser. An excimer laser, a carbon dioxide laser, a YAG laser, or the like is suitable as the laser.

As shown in FIG. 6 (j), Cr,
A Cu metal thin film 65 was formed.

As shown in FIG. 6K, a plating resist pattern 66 was formed on the surface of the optical wiring layer other than the pad portion, the land portion, and the electrical wiring portion.

As shown in FIG. 6 (l), the inside of the via hole, the pad portion, the land portion, and the electric wiring portion were subjected to copper plating in a copper sulfate bath using the metal thin film 65 as an electrode.

As shown in FIG. 6 (m), the plating resist 6
6, the metal thin film 65 is removed by soft etching, and a via hole 67, a pad, a land 68, and an electric wiring are formed, and the light and light of the second embodiment of the present invention are formed.
An electric wiring board was obtained.

<Third Embodiment of Method for Manufacturing Optical / Electrical Wiring Board> As a third embodiment of the method for manufacturing an optical / electrical wiring board, the optical / electrical wiring board shown in FIG. , Will be described in accordance with the flow of FIGS.

As shown in FIG. 7A, the first support 71
As a release layer 72 on a silicon wafer
A thin film layer of r and Cu was sputtered, and then a Cu layer was formed to about 10 μm in a copper sulfate plating bath.

As shown in FIG. 7B, a polyimide OPI-N1 is formed on the release layer 72 as a first cladding 73.
005 (manufactured by Hitachi Chemical Co., Ltd.)
It was imidized at 50 ° C. At this time, the film thickness was 20 μm.

As shown in FIG. 7C, the first clad 7
Polyimide OPI-N1305 as core 74 on 3
(Manufactured by Hitachi Chemical Co., Ltd.) and spin-coated
It was imidized at ℃. At this time, the film thickness was 8 μm.
The core and cladding materials used for this optical wiring layer are not limited to polyimide resins, but can be selected from polymer materials such as fluorinated or deuterated epoxy resins and methacrylate resins, depending on the wavelength of light used for optical signals. Materials with low loss can be selected.

Further, Al was vapor-deposited on the surface of the core layer, a predetermined pattern of photoresist was formed, and etching was performed to form Al metal masks 75 and 76.
The metal mask 75 indicates a core pattern to be an optical wiring, and the metal mask 76 indicates an alignment mark pattern.

Using oxygen gas as shown in FIG.
The core 74 was etched by reactive ion etching. Further, the Al film serving as a metal mask was removed by etching to form a core (optical wiring) pattern 77 and an alignment mark pattern 78 at the same time. At this time, the line width of the core pattern was 8 μm, the sectional shape was 8 μm in height,
It became a square having a width of 8 μm. The size of the cross section is not limited to this, and may vary depending on the transmission mode and the refractive index difference between the core and the clad.
It can be selected from μm to 100 μm.

As shown in FIG. 7E, the second clad 7
As No. 9, OPI-1005 is similarly coated and imidized. The cladding thickness at this time is 20 on the core optical wiring layer.
μm.

As shown in FIG. 7F, the second clad 79
On the surface of, sputtered a thin layer of Cr, Cu,
A Cu layer of about 10 μm was formed in a copper sulfate plating bath. Further, a pattern of a photoresist was formed by a photolithography technique, and etching was performed with an etchant to form a pad 80, an electric wiring, and a land. An opening 81 for forming a hole for forming a via hole with a laser later was previously provided in the land. Although not shown, pads, electrical wiring, and lands for electrical component connection were also formed at the same time.

As shown in FIG. 7G, a photoresist 82 was coated as a protective film in order to protect the pad 80, the electric wiring and the land formed of copper from the stripping solution.

As shown in FIG. 7 (h), the Cu layer in the release layer was dissolved using a ferric chloride solution as a release liquid, and the optical wiring layer was peeled off to produce an optical wiring film.

As shown in FIG. 7 (i), the side on which the pads, electric wiring and lands on the optical wiring layer are formed is adhered to the second support 83 with an adhesive. The second support 83 is provided with the alignment mark 7 from the side where the light distribution layer is not bonded.
Use a transparent one so that 8 can be seen. Further, as the adhesive, an adhesive which is easily peeled off or an adhesive whose adhesive strength is reduced by curing with ultraviolet rays is used.

Further, a thin film layer of Cr and Cu was sputtered on the surface opposite to the bonding surface of the optical wiring layer, and a Cu layer was formed to about 10 μm in a copper sulfate plating bath. further,
A photoresist pattern was formed by a photolithography technique, and etching was performed with an etchant, thereby forming a laser mask 84 for forming a mirror. An opening 85 is formed in the laser mask, and only the opening can be processed by irradiating a laser beam. The position of the present laser mask is also defined by the alignment mark 78 similarly to the pad on the opposite surface.

As shown in FIG. 7 (j), a mirror was formed at a 45 ° angle with the substrate by irradiating the laser mask portion with a laser at an angle of 45 ° with respect to the substrate surface. As the laser, an excimer laser, a carbon dioxide laser, a YAG laser, or the like is suitable.

As shown in FIG. 7 (k), the laser mask 8
4 was removed with an etching solution.

As shown in FIG. 7 (l), a modified polyimide resin 89 exhibiting thermoplasticity is coated on a substrate 87 having an electric wiring 88 by 20 μm as an adhesive and dried.
The mirror-processed surface of the optical wiring layer was bonded and heated and bonded.

As shown in FIG. 7 (m), the second support 83 was peeled off by irradiating ultraviolet rays.

As shown in FIG. 7 (n), a plating resist 90 was coated on the optical wiring layer as a protective film.

As shown in FIG. 7 (o), as a position for forming a via hole, a hole 91 for a via hole was formed in the opening 81 of the land using a laser. As a laser,
Excimer laser, carbon dioxide laser, YAG laser and the like are suitable.

As shown in FIG. 7 (p), C was sputtered into the surface of the optical wiring layer and the inside of the laser-processed hole.
A metal thin film of r and Cu was formed, and the inside of the via hole and the land were copper-plated in a copper sulfate bath using the metal thin film as an electrode. Further, the plating resist 90 as a protective film was removed, and a via hole 92 and a land 93 were formed to obtain an optical / electrical wiring board according to the third embodiment of the present invention.

Although not described in detail, in the third embodiment of the present invention, in FIG. 7 (f), when a pad, a land and an electric wiring are formed, a laser A mirror can also be formed by forming a mask and performing laser processing on the substrate at an angle of 45 °. As a result, not only can the process be simplified, but also the positions of the pad and the mirror can be accurately determined by one photomask.

<Fourth Embodiment of Method for Manufacturing Optical / Electrical Wiring Board> As a fourth embodiment of the method for manufacturing an optical / electrical wiring board, the optical / electrical wiring board shown in FIG. 8 (a) to 8 (q).

As shown in FIG. 8A, a release layer 102 is formed on a silicon wafer serving as a support 101 as a release layer 102.
A Cu thin film layer was sputtered, and then a Cu layer was formed to about 10 μm in a copper sulfate plating bath.

As shown in FIG. 8B, a polyimide OPI-N is formed on the release layer 102 as a first cladding 103.
1005 (manufactured by Hitachi Chemical Co., Ltd.)
It was imidized at 350 ° C. The film thickness at this time is 20 μm
Met.

As shown in FIG. 8C, the first clad 1
03 as a core 104 as a polyimide OPI-N13
05 (manufactured by Hitachi Chemical Co., Ltd.)
It was imidized at 50 ° C. At this time, the film thickness was 8 μm. The core and cladding materials used for this optical wiring layer are not limited to polyimide resins, but can be selected from polymer materials such as fluorinated or deuterated epoxy resins and methacrylate resins, depending on the wavelength of light used for optical signals. Materials with low loss can be selected.

Further, Al was vapor-deposited on the surface of the core layer, a predetermined pattern of photoresist was formed, and etching was performed to form Al metal masks 105 and 106. The metal mask 105 indicates a core pattern to be an optical wiring, and the metal mask 106 indicates an alignment mark pattern.

As shown in FIG. 8D, oxygen gas is used.
The core 104 was etched by reactive ion etching. Further, the Al film serving as a metal mask was removed by etching to form a core (optical wiring) pattern 107 and an alignment mark pattern 108 at the same time. At this time, the line width of the core pattern was 8 μm, and the cross-sectional shape was 8 μm in height.
m and a width of 8 μm. The size of the cross section is not limited to this, and can be selected from 5 μm to 100 μm depending on the transmission mode and the refractive index difference between the core and the clad.

As shown in FIG. 8E, the second clad 1
As O09, OPI-1005 is similarly coated and imidized. The cladding thickness at this time is 2 on the core optical wiring layer.
It was 0 μm.

As shown in FIG. 8F, the second clad 10
On the surface of No. 9, a thin layer of Cr and Cu was sputtered, and a Cu layer was formed in a thickness of about 10 μm in a copper sulfate plating bath. Further, a pattern of a photoresist was formed by a photolithography technique, and etching was performed with an etching solution to form a pad 110, an electric wiring, and a land. An opening 111 for forming a hole for forming a via hole by a laser later was previously provided in the land. Although not shown, pads, electrical wiring, and lands for electrical component connection were also formed at the same time.

As shown in FIG. 8 (g), a photoresist 112 was coated as a protective film in order to protect the pad 110, the electric wiring and the land made of copper from the stripping solution.

As shown in FIG. 8H, the Cu layer in the release layer was dissolved using a ferric chloride solution as the release liquid, and the optical wiring layer was peeled off to produce an optical wiring film.

As shown in FIG. 8 (i), the side on which the pads, electric wiring and lands on the optical wiring layer are formed is bonded to the second support 113 with an adhesive. Second support 11
3 is a transparent one so that the alignment mark 108 can be seen from the side where the light distribution layer is not bonded. Also,
As the adhesive, an adhesive which is easy to peel off or an adhesive whose adhesive strength is reduced by being cured by ultraviolet rays is used.

As shown in FIG. 8 (j), the core pattern 10
A mirror 114 was formed on a part of the core pattern 107 at an angle of 45 ° with respect to the substrate by machining a part of the core pattern 107 with reference to an alignment mark (not shown) formed at the same time when the substrate 7 was formed.

As shown in FIG. 8 (k), a modified polyimide resin 117 showing thermoplasticity is coated on the substrate 115 having the electric wiring 116 by 20 μm as an adhesive, dried, and the mirror-processed surface of the optical wiring layer is formed. Bonding and heat bonding were performed.

As shown in FIG. 8 (l), the second support 113 was peeled off by irradiation with ultraviolet rays.

As shown in FIG. 8M, a plating resist 118 was coated on the optical wiring layer as a protective film.

As shown in FIG. 8 (n), a hole 119 for a via hole was formed in the opening 111 of the land by a laser as a position for forming a via hole. As the laser, an excimer laser, a carbon dioxide laser, a YAG laser, or the like is suitable.

As shown in FIG. 8 (o), the surface of the optical wiring layer and the inside of the laser-processed hole are C
A metal thin film of r and Cu was formed, and the inside of the via hole and the land were copper-plated in a copper sulfate bath using the metal thin film as an electrode. Further, the plating resist 118 was removed, and a via hole 120 and a land 121 were formed.

As shown in FIG. 8 (p), on the surface of the optical wiring layer,
The polyimide OPI-N1005 (manufactured by Hitachi Chemical Co., Ltd.) used for the clad was spin-coated and imidized at 350 ° C. At this time, the film thickness was 10 μm.

As shown in FIG. 8 (q), the pad portion was irradiated with laser light with reference to the alignment mark 108 to remove the polyimide on the pad. As the laser, an excimer laser, a carbon dioxide laser, a YAG laser, or the like is suitable. Thus, an optical / electrical wiring board according to the fourth embodiment of the present invention was obtained.

Although a detailed description is omitted, the polyimide OPI similarly used for the clad is formed on the optical wiring layer of the optical / electrical substrate manufactured in the second to third embodiments.
-N1005 (manufactured by Hitachi Chemical Co., Ltd.) layer was formed, and the polyimide on the pad was removed.
And the optical / electrical wiring board described in (b) can be manufactured.

3. Mounting substrate FIGS. 9A and 9B show a configuration in which a light emitting element and a light receiving element as optical components are mounted on the optical / electrical wiring board of the present invention.
Shown in FIG. 10 shows a form in which a BGA package 141 having solder balls 142 is mounted as an electric component.
Shown in

In FIG. 9A, the laser light 135 emitted from the light emitting surface 132 of the light emitting element 131 is reflected by the mirror 134.
And propagates through the core of the optical wiring layer. FIG.
In (b), the laser light propagating through the core of the optical wiring layer is reflected by the mirror 139, and is reflected on the light receiving surface 1 of the light receiving element 136.
37.

The electrical connection between the optical component and the optical / electrical wiring board is made by solder balls 133 and 138. In the case of the optical component having metal leads, the optical component is soldered to the pad.

As described above, by simultaneously forming the core and the alignment mark, the position of the pad with respect to the alignment mark, the position of the mirror formed by machining, or the mirror formed by the laser mask is used. Is determined accurately. Further, the positions of the light emitting surface and the light receiving surface of the optical component are determined with high accuracy due to the self-alignment effect of the solder for joining the pad and the optical component. In addition, a resin layer of the same material as the refractive index of the clad is formed on the surface of the optical wiring layer, and the resin on the pad surface is removed with a laser based on the alignment mark. The positional accuracy of the optical component is increased.

Therefore, the optical component can be precisely aligned with the optical axis of the optical waveguide only by surface mounting the optical component on the optical / electrical wiring board through the reflow furnace, similarly to the electrical component shown in FIG. Became.

[0113]

The present invention has the following effects.

First, since the optical wiring layer is provided on the substrate having the electrical wiring, there is an effect that high-density mounting or miniaturization is possible.

Second, since the positional relationship between the core, the optical component pad, and the mirror is very close to the intended one, it is easy to optically match the optical axis of the optical component with the optical axis of the core. Therefore, there is an effect that the optical component and the electric component can be mounted simultaneously.

Third, since an electric wiring can be provided also on the optical wiring layer, there is an effect that crosstalk between the electric wirings can be suppressed.

Fourth, apart from a substrate having electric wiring,
Since the optical wiring layer is formed on the support and the optical wiring layer is bonded to the substrate, the electric wiring layer on the substrate is compared with the case where the optical wiring layer is formed directly on the electric wiring on the substrate. There is an effect that the influence of the unevenness can be reduced and the loss of light propagation of the core can be reduced.

[Brief description of the drawings]

FIG. 1 is a top view showing an optical / electrical wiring board of the present invention.

FIG. 2 is a top view showing the optical / electrical wiring board of the present invention.

FIG. 3 is a sectional view showing an optical / electrical wiring board according to the present invention.

FIG. 4 is a sectional view showing an optical / electrical wiring board according to the present invention.

FIG. 5 is a cross-sectional view illustrating a method for manufacturing an optical / electrical wiring board according to the present invention.

FIG. 6 is a cross-sectional view illustrating a method for manufacturing an optical / electrical wiring board according to the present invention.

FIG. 7 is a cross-sectional view illustrating a method of manufacturing an optical / electrical wiring board according to the present invention.

FIG. 8 is a cross-sectional view illustrating a method for manufacturing an optical / electrical wiring board according to the present invention.

FIG. 9 is a cross-sectional view illustrating a structure in which an optical component is mounted on the optical / electrical wiring board of the present invention.

FIG. 10 is a cross-sectional view illustrating a structure in which electric components are mounted on the optical / electrical wiring board of the present invention.

FIG. 11 is a sectional view showing a structure in which electric components are mounted on a conventional electric wiring board.

FIG. 12 is a cross-sectional view showing a structure in which an optical element or an electric element is mounted on a conventional optical / electrical wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Core 2 ... Clad 3 ... Mirror 4 ... Alignment mark 5 ... Pad 6 ... Land 7 ... Electrical wiring 8 ... Alignment mark 9 ... Substrate 10 ... Electrical wiring 11 ... Adhesive layer 12 ... Via hole 13 ... Optical wiring layer 14 ... Resin Layer 15: Hole 21: First support 22: Release layer 23: First clad 24: Core 25: Metal mask 26: Metal mask 27: Core pattern 28: Alignment mark 29: Second clad 30: Pad DESCRIPTION OF SYMBOLS 31 ... Opening part 32 ... Protective film 33 ... Second support 34 ... Mirror 35 ... Substrate 36 ... Electrical wiring 37 ... Adhesive layer 38 ... Protective film 39 ... Hole 40 ... Via hole 41 ... Land 51 ... Support 52 Release layer 53 First clad 54 Core 55 Metal mask 56 Metal mask 57 Core pattern 58 Alignment mark 59 ... second clad 60 ... mirror 61 ... substrate 62 ... electric wiring 63 ... adhesive layer 64 ... hole 65 ... metal thin film 66 ... plating resist 67 ... via hole 68 ... land 71 ... first support 72 ... peeling layer 73 first clad 74 core 75 metal mask 76 metal mask 77 core pattern 78 alignment mark 79 second clad 80 pad 81 opening 82 protective film 83 second support 84 ... Laser mask 85 ... Opening 86 ... Mirror 87 ... Substrate 88 ... Electrical wiring 89 ... Adhesive layer 90 ... Protective film 91 ... Hole 92 ... Via hole 93 ... Land 101 ... First support 102 ... Release layer 103 ... First clad 104: core 105: metal mask 106: metal mask 107: core pattern 108: alignment marker 109 ... second clad 110 ... pad 111 ... opening 112 ... protective film 113 ... second support 114 ... mirror 115 ... substrate 116 ... electrical wiring 117 ... adhesive layer 118 ... protective film 119 ... hole 120 ... via hole 121 land 122 resin layer 123 opening 131 light emitting element 132 light emitting surface 133 solder ball 134 mirror 135 laser light 136 light receiving element 137 light receiving surface 138 solder ball 139 mirror 140 laser light 141 ... Electrical component 142 ... Solder ball 151 ... Electrical element 152 ... Build-up multilayer laminate 153 ... Bump 154 ... Solder ball 155 ... Electrical wiring board 156 ... Electrical wiring 157 ... Pad 161 ... Electrical element 162 ... BGA package 163 ... Solder ball 164 ... Electrical wiring board 165 ... Electrical wiring 166: Optical element 167: Optical fiber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H047 KA04 KB08 LA09 PA02 PA24 PA28 QA05 RA08 TA05 TA23 TA44 5E338 AA03 BB63 BB75 CC01 CC10 CD32 DD11 DD32 EE22 EE23 EE43

Claims (7)

[Claims] An electric wiring on a substrate having electric wiring,
An optical / electrical wiring board comprising an optical wiring layer having a core for transmitting light and a cladding for burying the core, wherein a mirror provided on a part of the core and an optical component are soldered immediately above the mirror. An optical / electrical wiring board, comprising: a pad provided for attaching the pad; and a via hole for electrically connecting the pad to an electric wiring of the board. 2. The method according to claim 1, further comprising the step of:
An optical / electrical wiring board comprising an optical wiring layer having a core for transmitting light and a cladding for burying the core, wherein a mirror provided on a part of the core and an optical component are soldered immediately above the mirror. A pad for an optical component provided for attachment; a pad for an electrical component provided on an optical wiring layer for soldering an electrical component; and a pad for an optical component or an electrical component and electrical wiring between the substrate. An optical / electrical wiring board, comprising: a via hole for electrically connecting the circuit board; 3. The method according to claim 1, further comprising the step of:
An optical / electrical wiring board comprising an optical wiring layer having a core for transmitting light and a cladding for burying the core, wherein a mirror provided on a part of the core and an optical component are soldered immediately above the mirror. A pad for an optical component provided for attachment; a pad for an electrical component provided on an optical wiring layer for soldering an electrical component; and a pad for an optical component or an electrical component and electrical wiring between the substrate. An optical / electrical wiring board, comprising: a via hole for electrically connecting the optical wiring; and an electrical wiring provided on the optical wiring layer. 4. A resin layer having a refractive index equal to that of a clad is formed on a surface of an optical wiring layer, holes are formed on pads provided for soldering the optical component and the electrical component, and the surface of the pad is exposed. The optical / electrical wiring board according to any one of claims 1 to 3, wherein: 5. A step of forming, on a support, an optical wiring layer having an alignment mark for positioning, a core for transmitting light, and a clad for burying the alignment mark and the core, the core having a core based on the alignment mark. A step of bonding the optical wiring layer to a substrate having electrical wiring by partially providing a mirror, and placing a pad electrically connected to the electrical wiring on the substrate through a via hole on the optical wiring layer with reference to the alignment mark. A method of manufacturing an optical / electrical wiring board, comprising: forming a core and an alignment mark simultaneously. 6. A step of forming, on a support, an optical wiring layer having an alignment mark for positioning, a core for transmitting light, and a clad for burying the alignment mark and the core, the core having a core based on the alignment mark. A step of bonding the optical wiring layer to a substrate having electrical wiring by partially providing a mirror, and placing a pad electrically connected to the electrical wiring on the substrate through a via hole on the optical wiring layer with reference to the alignment mark. A method of manufacturing an optical / electrical wiring board, comprising the steps of: forming a resin layer equal to the refractive index of a clad on the surface of an optical wiring layer; and forming a hole based on an alignment mark. Forming an optical / electrical wiring board at the same time. 7. A mounting board, wherein an optical component and / or an electrical component is mounted on the optical / electrical wiring board according to claim 1.