JP4164947B2 - Optical / electrical wiring board, manufacturing method, and mounting board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical / electrical wiring board in which optical wiring and electrical wiring are mixed, a method for manufacturing the same, and a mounting board in which optical components and electrical components are mounted on the substrate.
[0002]
[Prior art]
In order to make a computer that can perform arithmetic processing faster, the clock frequency of the CPU tends to increase more and more, and about 1 GHz now appears. As a result, there are parts where high-frequency signals flow in the electrical wiring of copper on the printed circuit board in the computer, so malfunctions may occur due to the generation of noise, and electromagnetic waves may be generated, affecting the surroundings. It will also give.
[0003]
In order to solve such a problem, a part of the copper electrical wiring on the printed circuit board is replaced with an optical fiber or optical waveguide optical wiring, and an optical signal is used instead of the electrical signal. This is because the generation of noise and electromagnetic waves can be suppressed in the case of optical signals.
[0004]
From the viewpoint of high-density mounting or miniaturization, it is desirable to create an optical / electrical wiring board in which multiple electrical wirings and optical wirings are stacked on the same substrate. Matching the axes is very difficult.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the drawbacks of the related art, and provides an optical / electrical wiring board, a manufacturing method, and a mounting board that have a plurality of optical wirings and can easily align the optical axes of the optical wirings. This is the issue.
[0006]
[Means for Solving the Problems]
In order to achieve the above object in the present invention, the invention according to claim 1 is an optical / electrical wiring board having an electrical wiring for propagating an electric signal and an optical wiring for propagating the optical signal. The support has a flexible support formed on the support, and the support has a region in which electric wiring formed in a pattern on the support and an insulating layer covering the surface are formed. The region is provided on one side and the other side at intervals on the support so that the support can be flexible at an intermediate portion, The support is bent so that it does not break at the interval, the one side and the other side are overlapped and fixed, and the optical wiring maintains a continuous body between the one side and the other side. It is an optical / electrical wiring board characterized by the above.
[0007]
The invention according to claim 2 is based on the invention according to claim 1, and the electrical wiring on the one side and the other side of the support is connected by a via hole. It is a wiring board.
[0008]
According to a third aspect of the present invention, there is provided a method of manufacturing an optical / electrical wiring board having an electric wiring for propagating an electric signal and an optical wiring for propagating an optical signal, wherein the optical wiring is a continuous body on a flexible support. A step of providing a pattern-like electric wiring and a region having an insulating layer covering the surface on the support so as to oppose both surfaces of the support, and the support is flexible at an intermediate portion. A step of providing the region on one side and the other side of the support so as to maintain the property, bending the support so that it does not break at the interval, and between the one side and the other side. And at least a step of superposing and fixing the one side and the other side while maintaining the continuum of the optical wiring.
[0009]
The invention described in claim 4 is based on the invention described in claim 3, and further comprises a step of electrically connecting the electrical wiring on the one side and the other side of the support by via holes. It is a manufacturing method of the optical / electrical wiring board according to claim 3.
[0010]
Furthermore, the invention described in claim 5 is a mounting board in which an optical component and / or an electrical component is mounted on the optical / electrical wiring board described in any one of claims 1 to 2.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In the optical / electrical wiring board according to the present invention, cross-sectional explanatory views of the manufacturing process are shown in FIGS. 1 (1) to (4), and a plan view of the completed optical / electrical wiring board is shown in FIG. 1 (5). A mounting board on which is mounted is shown in FIG.
[0012]
In the production of the optical / electrical wiring board according to the present invention, first, an optical wiring is provided as a continuous body on a flexible support.
[0013]
Referring to FIG. 1 (1), the support is made of a film substrate having flexibility such as polyethylene naphthalate, preferably having a high glass transition temperature Tg, a high insulation resistance, and a low coefficient of thermal expansion. Use. In addition, in order to prevent noise from the outside to the optical wiring, it is also preferable to have a light shielding property except in the vicinity of a mirror described later.
[0014]
On one side of such a support, a flexible and good optical property resin such as fluorinated polyimide is laminated by solution coating or film to form a continuous optical wiring 2. The reason why the continuum is used is to omit the step of connecting a plurality of optical wirings and matching the optical axes. The optical wiring may be made of a single resin. However, in order to reduce the loss of the optical signal, a resin having a different refractive index may be used to have a structure such as an optical fiber core and cladding.
[0015]
A mirror 3 having a surface inclined by 45 degrees from the in-plane direction of the optical / electrical wiring board is formed at a predetermined portion of the optical wiring. The mirror at one end of the optical wiring reflects the optical signal emitted from the laser light emitting element mounted on the surface of the optical / electrical wiring board by 90 degrees and propagates the light / electrical wiring board. The mirror at the other end reflects the optical signal propagated through the optical / electrical wiring board by 90 degrees and makes it incident on a laser light receiving element mounted on the surface of the optical / electrical wiring board. This mirror can be formed by a method of providing a taper by processing such as dicing, laser or dry etching, or a method using a holographic technique. It is preferable to form a reflective film on the mirror surface.
[0016]
Thereafter, in order to protect the optical wiring, a flexible resin is laminated to obtain the support 1 on which the optical wiring is formed. Such a resin preferably has a light shielding property to prevent noise from the outside to the optical wiring.
[0017]
In addition, as another method for forming a mirror on the support, it is also possible to perform a method in which an optical wiring and a resin are laminated on the support and then a predetermined portion is perforated obliquely by laser or dry etching.
[0018]
Next, a front surface layer and a back surface layer having electrical wiring are provided on the support at intervals.
[0019]
Referring to FIG. 1B, a metal foil such as copper is laminated on both surfaces of the support 1 on which the optical wiring is formed, and patterned by a known photolithography method to form the electrical wiring 4. Thereafter, an insulating resin is applied to form the insulating layer 5. At this time, it is preferable to provide an opening 9 for exposing the mirror in the insulating layer 5.
[0020]
As another method for forming the electrical wiring, a subtracting method or an additive method used in manufacturing a printed wiring board by built-up can be used.
[0021]
By the way, the electric wiring 4 and the insulating layer 5 are not provided on the entire surface of the support 1 but are provided at a predetermined interval 6. This is because it is a bent portion at the time of superposition described later. In FIG. 1 (2), the left portion of the interval 6 is referred to as a surface layer 7, and the right portion is referred to as a back layer 8. Further, if a plurality of intervals 6 are provided to form a front surface layer, an intermediate layer, and a back surface layer, a multilayer optical / electrical wiring board can be obtained.
[0022]
Next, the front surface layer and the back surface layer are overlapped and fixed with the interval approximately in the center.
[0023]
Describing with reference to FIG. 1 (3), the front surface layer and the back surface layer are overlapped with each other on the inner side so that the support is not bent and the interval is substantially in the center. At that time, an adhesive 10 such as a prepreg having the same size as the surface layer is also sandwiched. Then, it heats and pressurizes with a hot press, a heat roller, etc., and a surface layer, an adhesive agent, and a back layer are fixed. It should be noted that a multilayer optical / electrical wiring board can be obtained by using an ordinary electric wiring board sandwiched between prepregs instead of a simple prepreg.
[0024]
Furthermore, if necessary, the electrical wiring of the front surface layer and the back surface layer is electrically connected by a via hole.
[0025]
Explaining with reference to FIG. 1 (4) (AA 'cross section in FIG. 1 (5)), is it possible to completely drill the optical / electrical wiring board in the thickness direction by a high-power laser such as an excimer laser or a drill? The via hole 11 is formed by partially drilling. After that, by filling the perforations with a conductive material using a plating method or the like, electrical connection can be established between the electrical wirings, so that an electrical signal can be propagated.
[0026]
A plan view of the optical / electrical wiring board manufactured in this way is shown in FIG.
In the figure, the surface layer 7 has the optical wiring 2 embedded therein. The optical wiring 2 is provided in the support 1 and is a continuous body with the optical wiring on the back surface layer. The surface layer 7 is provided with an opening 9 from which the mirror formed on the optical wiring 2 is exposed. Four optical component mounting pads 12 exist around the opening 9 and are connected to the lead frame or pad of the optical component by solder or solder balls. Furthermore, there are pads for mounting electrical components (not shown).
[0027]
Optical components and electrical components were mounted on the surface of the optical / electrical wiring board.
[0028]
A cross section of such a mounting substrate is shown in FIG. A CPU, a memory (not shown), a laser light emitting element 13 and a laser light receiving element 14 are mounted on the mounting board. The electric signal from the CPU on the mounting substrate was modulated, and the laser light emitting element 13 propagated the optical wiring through the mirror as an optical signal. Then, the optical signal propagated through the optical wiring was reflected by the mirror and demodulated into an electric signal by the laser light receiving element, and could be propagated to the bus without generating noise.
[0029]
【The invention's effect】
According to the present invention, since a plurality of optical wirings are continuous bodies, an optical / electrical wiring board and a mounting board in which the optical axes of the optical wirings naturally coincide with each other without a step of connecting difficult optical wirings. Can be provided.
[0030]
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an optical / electrical wiring board according to the present invention.
FIG. 2 is an explanatory diagram of a mounting board in which optical components are mounted on the optical / electrical wiring board according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Support body in which optical wiring was formed 2 Optical wiring 2 Mirror 4 Electrical wiring 5 Insulating layer 6 Space | interval 7 Surface layer 8 Back surface layer 9 Opening part 10 Adhesive 11 Via hole 12 Optical component mounting pad 13 Laser light emitting element 14 Laser light receiving element

Claims (5)

In an optical / electrical wiring board having electrical wiring for propagating electrical signals and optical wiring for propagating optical signals,
Having a flexible support on which a continuous optical wiring is formed;
The support is provided with an electric wiring formed in a pattern on the support and a region where an insulating layer covering the surface is formed so as to face both surfaces of the support, and the support The region is provided on one side and the other side of the support so as to maintain flexibility at an intermediate portion.
The support is bent so that it does not break at the interval, and the one side and the other side are overlapped and fixed;
And that the optical wiring maintains a continuous body between the one side and the other side,
Optical and electrical wiring board characterized by 2. The optical / electrical wiring board according to claim 1 , wherein electrical wirings on the one side and the other side of the support are connected by via holes. In a method of manufacturing an optical / electrical wiring board having an electrical wiring for propagating an electrical signal and an optical wiring for propagating an optical signal,
A step of providing an optical wiring as a continuous body on a flexible support;
A region having a pattern-like electric wiring and an insulating layer covering this surface on the support is opposed to both surfaces of the support, and the support can maintain flexibility at an intermediate portion. A step of providing the region on one side and the other side of the support with a space therebetween,
Bending the support so that it does not break at the interval, and maintaining the optical wiring in a continuous state between the one side and the other side, and stacking and fixing the one side and the other side ;
A method for manufacturing an optical / electrical wiring board, comprising: 4. The method of manufacturing an optical / electrical wiring board according to claim 3, further comprising a step of electrically connecting the electric wirings on the one side and the other side of the support by via holes. A mounting substrate in optical and electrical wiring board according to any one of claims 1 to 2, characterized in that mounting the optical parts and / or electrical components.

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