JP2000340957A - Optical / electrical wiring board, manufacturing method, and mounting board - Google Patents

Abstract

(57) [Problem] To provide an optical / electrical wiring board capable of high-density mounting or miniaturization and capable of mounting optical components in the same manner as mounting of electrical components. An electric wiring (1) of a substrate 14 having an electric wiring is provided.
7 and 19), an optical fiber 1 for transmitting an optical signal
An optical / electrical wiring board provided with an optical wiring layer 15 having: a mirror 2 provided on a part of an optical fiber 1; an optical fiber 1 provided on a first resin layer 3; The optical wiring layer 15 on which the resin layer 4 is provided, the projection 3a made of the first resin layer for fixing an optical fiber, the projection 3b made of the first resin layer for mounting an optical component, and the like. A metal pad (6 or 8) disposed thereon; and a via hole (21 or 20) for electrically connecting the metal pad (6 or 8) to an electric wiring (17 or 19) of the substrate 14. Optical / electrical wiring board

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 a mounting board on which an optical component and an electric component are mounted.

[0002]

2. Description of the Related Art In order to produce a computer capable of performing arithmetic processing faster, the clock frequency of a CPU tends to increase more and more, and a clock frequency of about 1 GHz has recently appeared. As a result, high-frequency signals flow through the copper electrical wiring on the printed circuit board in the computer, which may cause malfunctions due to noise, or may cause electromagnetic waves to affect the surrounding environment. Will also give.

In order to solve such a problem, a part of copper electric wiring on a printed circuit board is replaced by an optical fiber or an optical waveguide, and an optical signal is used instead of an electric signal. ing. This is because, in the case of an optical signal, generation of noise and electromagnetic waves can be suppressed.

[0004] From the viewpoint of high-density mounting or miniaturization, optical and optical wiring are stacked on the same substrate.
Although it is desirable to make an electrical wiring board, the conventional optical / electrical wiring board optically aligns the optical axis of the optical component with the optical axis of the optical wiring when mounting optical components such as laser light emitting elements and light receiving elements. Reconciliation was difficult and generally relied on skilled workers. Therefore, there is a disadvantage that mounting an optical component on an optical / electrical wiring board is extremely expensive compared to an electrical component that can be automatically soldered in a reflow furnace or the like.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the related art, and enables high-density mounting or miniaturization, and furthermore, mounting of optical components in the same manner as mounting of electrical components. An object of the present invention is to provide an optical / electrical wiring board that can be used.

[0006]

In order to achieve the above object, according to the present invention, an optical signal is transmitted as an optical wiring on an electric wiring of a substrate having an electric wiring. Light with an optical wiring layer having fibers
An electrical wiring board, a mirror provided on a part of an optical fiber, an optical wiring layer in which an optical fiber is provided on a first resin layer, and a second resin layer is provided thereon, First
A projection made of a resin layer for fixing an optical fiber, a projection made of a first resin layer for soldering an optical component and a metal pad provided thereon, and electrical wiring between the pad and the substrate And a via hole for electrical connection between the optical and electrical wiring boards.

According to a second aspect of the present invention, there is provided an optical / electrical wiring board including an optical wiring layer having an optical fiber for transmitting an optical signal as an optical wiring, on the electric wiring of the substrate having the electric wiring. A mirror provided on a part of the fiber, an optical fiber on which an optical fiber is provided on a first resin layer, and an optical wiring layer on which a second resin layer is provided, and a light comprising the first resin layer A projection for fixing the fiber, a projection made of the first resin layer for soldering the optical component, and a metal pad provided thereon; and an optical wiring layer for soldering the electrical component. An optical / electrical wiring board comprising: a pad for an electrical component provided thereon; and a via hole for electrically connecting an optical component or a pad for an electrical component to an electrical wiring of the substrate. is there.

According to a third aspect of the present invention, there is provided an optical / electrical wiring board comprising an optical wiring layer having an optical fiber for transmitting an optical signal as an optical wiring, on the electrical wiring of the substrate having the electrical wiring. A mirror provided on a part of the fiber, an optical fiber on which an optical fiber is provided on a first resin layer, and an optical wiring layer on which a second resin layer is provided, and a light comprising the first resin layer A projection for fixing the fiber, a projection made of the first resin layer for soldering the optical component, and a metal pad provided thereon; and an optical wiring layer for soldering the electrical component. An electrical component pad provided thereon, an optical component or a via hole for electrically connecting the electrical component pad to the electrical wiring of the substrate, and an electrical wiring provided on the optical wiring layer. Characteristic light
This is an electric wiring board.

Further, in the invention according to claim 4, the first member is provided on the support.
With the metal layer as a mask, the projection for fixing the optical fiber and the projection for the metal pad are simultaneously formed by etching using the metal film as a mask, and the optical fiber is set in accordance with the projection and placed on top of it. Forming a second resin layer and removing the second resin layer on the surface of the metal pad to form an optical wiring layer and a pad; and providing a mirror on a part of the optical fiber to electrically connect the optical wiring layer to the optical fiber. And a step of forming a via hole for electrically connecting the pad and the electric wiring on the substrate, the method comprising the steps of:

According to a fifth 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 third aspects. is there.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Optical / Electrical Wiring Board In the optical / electrical wiring board of the present invention, FIG. 1 is a top view of a portion on which an optical component is mounted. FIG. Figure 2
FIG. 3 is a sectional view taken along the optical fiber 1.

The optical / electrical wiring board according to the present invention comprises an electric wiring 16,
The optical wiring layer 15 is laminated on a substrate 14 having 17, 18, and 19 via an adhesive layer 13. The substrate 14 may be a single-layer insulating substrate or a multilayer wiring substrate in which electric wiring and insulating layers are alternately laminated. Further, as a constituent material, an insulating substrate in which a glass cloth is impregnated with a resin, a polyimide film, a ceramic substrate, or a multilayer wiring substrate based thereon may be used.

In the optical wiring layer 15, an optical fiber 1 is buried between a first resin layer 3 and a second resin layer 4 as an optical wiring for transmitting an optical signal. The optical fiber 1 includes a core layer 1b through which an optical signal propagates and a cladding layer 1a that confine the optical signal to the core layer. The optical fiber 1 is fixed between the protrusions 3a formed of the first resin layer 3, and the position of the core layer in the optical wiring layer is arbitrarily determined.

A mirror 2 is formed on the optical fiber to reflect a laser beam as an optical signal and change the propagation direction to 90 °. This mirror inserts an optical signal emitted vertically from the laser light emitting element mounted on the optical / electrical wiring board of the present invention toward the substrate into an optical fiber arranged in parallel with the substrate surface, or conversely, The optical signal propagating through the optical fiber is directed to the light receiving element installed on the optical / electrical wiring board of the present invention, and serves to change the propagation direction of the optical signal vertically. A surface forming 45 ° is formed. The mirror 2 may be provided with a reflective layer of a metal deposition film. Further, a material having a lower refractive index than the core layer 1b may be provided on the mirror surface. This mirror can be formed at an arbitrary position on the optical wiring layer using the alignment mark.

At the periphery of the mirror 2, pads 5, 6, 7, 8 for mounting optical components such as a laser light emitting element and a light receiving element are arranged. This pad is formed on the protrusion 3 b made of the first resin layer 3. The projection 3b made of the first resin layer under the pad and the projection 3a made of the first resin layer for fixing the optical fiber 1 can be simultaneously formed by a photolithography technique via one photomask. As a result, the position of the core layer, the position of the mirror, and the position of the pad of the optical fiber can be accurately determined. In addition, since the optical component can be soldered to the optical / electrical wiring board of the present invention through a reflow furnace, the self-alignment effect at the time of solder melting allows the light emitting surface of the laser light emitting element or the light receiving surface of the light receiving element to be connected. Position accuracy can also be improved.

The pads 6 and 8 for optical components are connected to electric wirings 17 and 19 via lands 10 and 12 of via holes and via holes 21 and 20. Optical component pads 5, 7
Although not shown, they are similarly connected to the optical wirings 16 and 18.

As the characteristics of the resin forming the first resin layer, those having a high glass transition temperature Tg, a high insulation resistance, and a low coefficient of thermal expansion are good. And the like. For example, a polyimide resin or an epoxy resin is suitable.

As the characteristics of the resin forming the second resin layer, those having a high glass transition temperature Tg, a high insulation resistance, and a low coefficient of thermal expansion are good as in the case of the first resin. It is necessary to select a material having the same refractive index as the cladding layer. Therefore, the same material as the second resin may be used as the resin of the first resin layer.

FIG. 4 is a cross-sectional view when the leads 34 of the laser light emitting element 32 such as a semiconductor laser are soldered on the pads 5, 6, 7, and 8. Laser light emitting element 32
The laser light 31 emitted from the laser light emitting surface 33 is reflected by the mirror 2 and propagates through the optical fiber 1.

FIG. 5 is a cross-sectional view when the leads 44 of the light receiving element 42 such as a photodiode are soldered on the pads 5, 6, 7, and 8. The laser light 41 propagating through the optical fiber 1 is reflected by the mirror 2 and
Incident on the light receiving surface 43 of the light emitting element.

As already mentioned, the mutual positional relationship between the core layer 1b of the optical fiber 1, the pad 5, the pad 6, the pad 7, the pad 8, and the mirror 2 is intended. Since the optical component coincides with the object with extremely high precision, when the leads of the optical component are placed on the pads 5, 6, 7, and 8, the optical axis of the optical component and the optical axis of the core layer of the optical fiber 1 optically match. become. Therefore, the optical component can be automatically soldered in a reflow furnace or the like.

A pad for soldering an electric component may be provided on the optical wiring layer of the optical / electrical wiring board,
Further, an electric wiring may be provided. The electric component pad may be electrically connected to the wiring on the substrate through the via hole in the same manner as the optical component pad.

When the electric wiring is provided on the optical wiring layer, the pad is electrically connected only to the electric wiring on the optical wiring layer, and
It may not be electrically connected to the electric wiring on the substrate. In this case, of course, there is no via hole for electrically connecting the pad and the electric wiring on the substrate.

2. Method for Manufacturing Optical / Electrical Wiring Board The method for manufacturing an optical / electrical wiring board of the present invention is basically as follows. First, apart from the board with the electrical wiring,
An optical wiring layer is formed on the support. At this time, a projection for fixing the optical fiber and a pad for soldering the optical component are simultaneously formed by photolithography. next,
A mirror is provided on a part of the optical fiber and bonded to the substrate. Further, a via hole for electrically connecting the pad and an electric wiring on the substrate is formed.

One embodiment will be described below in accordance with the flow of FIGS. 6A to 6N, focusing on a pad for an optical component electrically connected to an electric wiring on a substrate by a via hole.

As shown in FIG. 6A, the first support 51
The release layer 52 is formed thereon. As the first support 51, a material having excellent heat resistance and robustness and having a thermal expansion coefficient equal to or close to the thermal expansion coefficients of the first resin layer and the second resin layer is used. .

As shown in FIG. 6B, a first resin layer 53 is formed on the release layer 52.

A metal film is formed on the first resin layer 53, and as shown in FIG. 6C, the metal film is formed by a photolithography technique to form a projection pattern 5 for fixing an optical fiber.
4 and processing into a pad projection pattern 55 for mounting an optical component.

As shown in FIG. 6D, using a metal film as a metal mask, an optical fiber fixing projection 56 and an optical component mounting pad projection 57 are formed by dry etching.

The optical fiber 58 is fixed as shown in FIG.

As shown in FIG. 6F, the second resin layer 59
To form

As shown in FIG. 6G, the second resin layer 59
The second resin layer is removed by dry etching until the surfaces of the metal film patterns 54 and 55 are exposed from the upper surface of the substrate.

The optical wiring layer 60 is peeled off as shown in FIG. 6 (h) by immersing it in a peeling solution capable of dissolving and removing the peeling layer 52. Before immersion in a stripping solution, a protective film is formed on the metal film pattern formation surface as necessary (not shown).

As shown in FIG. 6I, the side on which the metal film pattern is formed is adhered to the second support 61. As the adhesive, an adhesive which is easy to peel off or an adhesive whose adhesive strength is reduced by curing with heat or ultraviolet rays is used.

As shown in FIG. 6J, a groove is formed in the optical wiring layer by dicing or dry etching to form a mirror 62.

As shown in FIG. 6 (k), the mirror 62 side of the optical wiring layer is bonded to the side of the substrate 63 having the electrical wiring 64 with an adhesive. As a result, the optical wiring layer 60 adheres to the substrate 63 with the adhesive layer 65 interposed therebetween.

As shown in FIG. 6 (l), the second support 61
From the optical wiring layer. Second support 61 and optical wiring layer 6
When an adhesive that is cured by heat or ultraviolet light is used when bonding the adhesive to the substrate, the adhesive is cured by heat or ultraviolet light and then peeled off.

As shown in FIG. 6M, a hole 66 for forming a via hole is formed near the optical component mounting pad 55 by a laser. In this case, the electric wiring 64 serves as a stopper during laser processing.

Further, the metal film pattern 54 formed on the optical fiber fixing protrusion is removed.

The via hole 6 is formed by the semi-additive method.
8 and a land 67 of a via hole connected to the pad 55, a metal layer is formed, and as shown in FIG.
The optical / electrical wiring board of the present invention is obtained. If necessary,
At the same time, a pad (not shown) for an electric component, a via hole (not shown) for electrically connecting the pad to the electric wiring, or an electric wiring (not shown) can be formed at the same time.

3. Manufacturing method of mounting board For optical / electrical wiring board, optical component (laser, photodiode) and electrical component (CPU, memory) are soldered,
Implemented.

[0042]

The present invention has the following effects.

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

Second, since the mutual positional relationship between the core layer of the optical fiber, the pad for mounting the optical component, and the mirror matches the intended one with extremely high accuracy, the optical axis of the optical component and the optical fiber It is easy to make the optical axis of the optical component coincide with the optical axis of the optical component easily, so that the optical component and the electrical component can be automatically mounted at the same time.

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

Fourth, apart from the substrate having the electric wiring,
Since the optical fiber is fixed to the optical wiring layer on the support and the optical wiring layer is adhered to the substrate, the electric wiring on the substrate is compared with the case where the optical fiber is directly installed on the electric wiring on the substrate. This has the effect of reducing the influence of the unevenness of the optical fiber and reducing the propagation loss of the optical signal of the optical fiber.

[0047]

[Brief description of the drawings]

FIG. 1 is a top view of a part for mounting an optical component in an optical / electrical wiring board according to the present invention.

FIG. 2 is a cross-sectional view of a portion where an optical component is mounted on the optical / electrical wiring board of the present invention, which crosses an optical fiber.

FIG. 3 is a cross-sectional view taken along an optical fiber in a portion where an optical component is mounted on the optical / electrical wiring board of the present invention.

FIG. 4 is a view for explaining propagation of laser light when a laser light emitting element is mounted on the optical / electrical wiring board of the present invention.

FIG. 5 is a view for explaining propagation of laser light when a light receiving element is mounted on the optical / electrical wiring board of the present invention.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical fiber 1a Optical fiber cladding layer 1b Optical fiber core layer 2 Mirror 3 First resin layer 3a Optical fiber fixing projection 3b Optical component mounting pad projection 4 Second resin layer 5 Optical component mounting Pad 6 Optical component mounting pad 7 Optical component mounting pad 8 Optical component mounting pad 9 Land 10 Land 11 Land 12 Land 13 Adhesive layer 14 Substrate 15 Optical wiring layer 16 Electrical wiring 17 Electrical wiring 18 Electrical wiring 19 Electrical wiring 20 Via hole 21 Via hole 31 Laser light 32 Laser light emitting element 33 Laser light emitting surface 34 Lead 35 Solder 41 Laser light 42 Light receiving element 43 Light receiving surface 44 Lead 45 Solder 51 First support 52 Release layer 53 First resin layer 54 Optical fiber fixing Metal thin film pattern for forming projections for optical components 55 56 Projection for fixing optical fiber 57 Projection for pad part for mounting optical component 58 Optical fiber 59 Second resin layer 60 Optical wiring layer 61 Second support 62 Mirror 63 Substrate 64 Electrical wiring 65 Adhesive layer 66 Hole 67 Land 68 Beer Hall

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Claims (5)

[Claims] An electric wiring on a substrate having electric wiring,
An optical / electrical wiring board including an optical wiring layer having an optical fiber for transmitting an optical signal as an optical wiring, wherein a mirror provided on a part of the optical fiber and an optical fiber are provided on a first resin layer. The second on it
An optical wiring layer provided with the first resin layer, a projection made of the first resin layer for fixing an optical fiber, a projection made of the first resin layer for soldering an optical component, and the same. An optical / electrical wiring substrate, comprising: a metal pad provided thereon; and a via hole for electrically connecting the pad and an electric wiring of the substrate. 2. The method according to claim 1, further comprising the step of:
An optical / electrical wiring board including an optical wiring layer having an optical fiber for transmitting an optical signal as an optical wiring, wherein a mirror provided on a part of the optical fiber and an optical fiber are provided on a first resin layer. The second on it
An optical wiring layer provided with the first resin layer, a projection made of the first resin layer for fixing an optical fiber, a projection made of the first resin layer for soldering an optical component, and the same. Electrical connection between the metal pad placed on top, the pad for electrical component provided on the optical wiring layer to solder the electrical component, the pad for optical component or electrical component, and the electrical wiring of the board An optical / electrical wiring board comprising: a via hole; 3. The method according to claim 1, further comprising the step of:
An optical / electrical wiring board including an optical wiring layer having an optical fiber for transmitting an optical signal as an optical wiring, wherein a mirror provided on a part of the optical fiber and an optical fiber are provided on a first resin layer. The second on it
An optical wiring layer provided with the first resin layer, a projection made of the first resin layer for fixing an optical fiber, a projection made of the first resin layer for soldering an optical component, and the same. Electrical connection between the metal pad placed on top, the pad for electrical component provided on the optical wiring layer to solder the electrical component, the pad for optical component or electrical component, and the electrical wiring of the board An optical / electrical wiring board comprising: a via hole; and an electric wiring provided on the optical wiring layer. 4. A first resin layer is coated on a support, and a projection for fixing an optical fiber and a projection of a metal pad are simultaneously formed by etching using a metal film as a mask to form an optical fiber. Install it along with the protrusion, and place a second
Forming the optical wiring layer and the pad by removing the second resin layer on the surface of the metal pad, and providing the optical wiring layer with electric wiring by providing a mirror on a part of the optical fiber. A method of manufacturing an optical / electrical wiring board, comprising: a step of bonding to a substrate; and a step of forming a via hole for electrically connecting a pad and an electric wiring on the substrate. 5. A mounting board, wherein an optical component and / or an electrical component is mounted on the optical / electrical wiring board according to claim 1.