JP2002006161A - Optical wiring substrate and optical wiring module and their manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring substrate and a wiring substrate module which make it possible to rapidly transmit signals and effectively prevent a damage caused by external factors, and their manufacturing method. SOLUTION: The electric wiring element 10 having electric wiring patterns 12a-12g formed on an insulating substrate 11 and an insulating layer 20 covering the electric wiring element 10 are provided, and an optical waveguide 30 as an optical wiring is provided in the insulating layer 20. A luminous element 40 and a light receiving element 50 are provided in the insulating layer 20, and IC chips 61 and 62 are provided on the opposite side to the electric wiring element 10 of the insulating layer 20. Since the optical waveguide 30 is provided in the insulating layer 20, the occurrence of the break of the optical wiring and an optical noise can be prevented, and the loss in optical propagation can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wiring board, an optical wiring module, and a method for manufacturing the same, which can increase the speed of information transmission signals.

[0002]

2. Description of the Related Art IC (Integrated Circuit)
Advances in technology for large scale integrated circuits (LSIs) and large scale integrated circuits (LSIs) have increased their operating speeds and integration scales. For example, the performance of microprocessors and the capacity of memory chips have been rapidly increased. I have. Conventionally, information transmission over a relatively short distance, such as between boards in a device or between chips in a board, has been performed mainly by electric signals. In the future, in order to further improve the performance of integrated circuits, it is necessary to increase the speed of signals and the density of signal wiring, but in the case of electric signal wiring (electric wiring),
It is difficult to increase the speed and increase the density, and the signal delay due to the CR (C: capacitance of the wiring, R: resistance of the wiring) time constant becomes a problem. In addition, high-speed electric signals and high-density electric wiring have been developed by using EMI (Electromag
netic Interference) Because it causes noise and crosstalk between channels, countermeasures are also indispensable.

In order to solve these problems, optical wiring (optical signal wiring, optical interconnection) has been receiving attention. Optical wiring is considered to be applicable to various places, such as between devices, between boards in a device, or between chips in a board. Above all, for signal transmission over a short distance such as between chips, it is preferable to form an optical waveguide on a substrate on which the chip is mounted and to construct an optical transmission / communication system using this as a transmission path. It is believed that there is.

In such an optical transmission / communication system, a light emitting element for converting an electric signal to an optical signal, a light receiving element for converting an optical signal to an electric signal, and a light emitting element and a light receiving element. IC for sending and receiving electric signals
A chip or the like must be provided, and power supply to these elements and transmission of various control signals at a relatively low speed still need to be performed by electric signals. Therefore, it is essential to form an electric wiring on or on the substrate.

[0005]

A hybrid type optical wiring board having an electric wiring and an optical wiring is, for example, a thin film multilayer wiring as an electric wiring is formed on a silicon substrate or a glass substrate, and an optical wiring is formed thereon. It is considered that this is obtained by forming an optical waveguide as a wiring. It can also be obtained by forming an optical waveguide on a substrate having electric wiring such as a normal printed wiring board. In the case of manufacturing these hybrid type optical wiring substrates, it is conceivable to form them by a low-temperature process using a polymer compound as the material of the optical waveguide.

However, when the optical waveguide is arranged so as to be exposed on the substrate, the optical waveguide is liable to be mechanically damaged. For this reason, there is a problem that a part of the optical waveguide is disconnected, a light propagation loss is generated, and optical noise due to leaked light is generated. In addition, since the optical waveguide is present on the surface of the substrate, the semiconductor chip and other chip components must be mounted so as to avoid the optical waveguide, which limits the mounting area of the entire wiring substrate. There are also problems.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide an optical wiring board which enables high-speed transmission of signals and effectively prevents damage due to external factors. An object of the present invention is to provide an optical wiring module and a manufacturing method thereof.

[0008]

An optical wiring board according to the present invention comprises: a base having an electric wiring pattern;
And an optical waveguide arranged to transmit an optical signal.

An optical wiring module according to the present invention comprises: a base having an electric wiring pattern; an optical waveguide disposed inside the base so as to transmit an optical signal; a light emitting element for transmitting an optical signal; And an integrated circuit for transmitting and receiving an electric signal between at least one of the light emitting element and the light receiving element.

In the method of manufacturing an optical wiring board according to the present invention, a step of forming a lower insulating layer on an electric wiring portion on which an electric wiring pattern is formed, and a step of transmitting an optical signal on the lower insulating layer. Forming a possible optical waveguide; and forming an upper insulating layer to cover at least the optical waveguide.

In the method of manufacturing an optical wiring module according to the present invention, a step of forming a lower insulating layer on an electric wiring portion on which an electric wiring pattern is formed, and a step of transmitting an optical signal on the lower insulating layer. Forming a possible optical waveguide; forming an upper insulating layer so as to cover at least the optical waveguide; and forming a light emitting element for transmitting an optical signal and a light receiving element for receiving the optical signal. Forming an integrated circuit for transmitting and receiving an electric signal to and / or from at least one of the light emitting element and the light receiving element on the upper insulating layer.

In the optical wiring board or the optical wiring module according to the present invention, the electric signal is transmitted by the electric wiring provided on the base, and the optical signal is transmitted by the optical waveguide inside the base.

In the method of manufacturing an optical wiring board or the method of manufacturing an optical wiring module according to the present invention, an optical waveguide is formed on a lower insulating layer formed on an electric wiring portion, and an upper portion is formed so as to cover the optical waveguide. An insulating layer is formed.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] First, a first embodiment of the present invention will be described.
Configurations of the optical wiring board and the optical wiring module according to the embodiment will be described.

FIG. 1 shows a sectional structure of an optical wiring board according to the present embodiment. The optical wiring board includes an electric wiring section 10 and an insulating layer 20 provided so as to cover the electric wiring section 10. Inside the insulating layer 20,
An optical waveguide 30, a light emitting element 40, and a light receiving element 50 as optical wiring are embedded. Here, the combination of the electric wiring portion 10 and the insulating layer 20 corresponds to a specific example of the “base” of the present invention.

The electric wiring section 10 is a substrate 1 having an insulating property.
1 and a plurality of electric wiring patterns 12 a to 12 g provided on the surface and inside of the substrate 11 and made of a conductive material such as copper (Cu). The electric wiring patterns 12a to 12d are formed inside the substrate 11, and the electric wiring patterns 12e to 12g are formed on one surface (the back surface in FIG. 1) of the substrate 11. Electric wiring pattern 1
The 2c and the electric wiring pattern 12d are formed, for example, on the same level (hereinafter, referred to as a first level), but are electrically insulated from each other. Further, the electric wiring patterns 12a and 12d are respectively formed in two layers different from the first layer, for example. That is, here, the electric wiring patterns 12a to 12g
Is multilayered.

The electric wiring pattern 12a is
The electric wiring pattern 12b is a power supply line for the light receiving element 50. Electric wiring pattern 1
Reference numeral 2c denotes a power supply line for an IC chip 61 (see FIG. 3) described later, and an electric wiring pattern 12d denotes an I
This is a power supply line for the C chip 62 (see FIG. 3). The power supply wiring patterns 12e to 12g are for electrically connecting other elements (not shown).

On the other surface of the substrate 11, electrodes 14 and 15 to which a power supply voltage is applied from the outside are provided. A connection hole (through hole) 13a is formed between the electrode 14 and the electric wiring pattern 12a. The electrode 14 is electrically connected to the electric wiring pattern 12a via a conductor such as copper filled in the connection hole 13a. It is connected to the. A connection hole 13b is formed between the electrode 15 and the electric wiring pattern 12b, and the electrode 15 is electrically connected to the electric wiring pattern 12b via a conductor filled in the connection hole 13b. Here, the electrode 14 corresponds to a specific example of the “second power supply electrode” in the present invention, and the electrode 15 corresponds to a specific example of the “fourth power supply electrode” in the present invention.

The light emitting element 40 is disposed to face the electrode 14. The light emitting element 40 has a power supply electrode 40a for applying a power supply voltage, a signal electrode 40b for applying an electric signal, and a light emitting section 40c. The power supply electrode 40a is in contact with the electrode 14, or is connected to the electrode 14 by soldering or the like and is electrically connected to the electrode 14. Here, the power supply electrode 40a corresponds to a specific example of the “first power supply electrode” of the present invention, and the signal electrode 40b corresponds to a specific example of the “first signal application electrode” of the present invention.

The light receiving element 50 is provided to face the electrode 15. The light receiving element 50 includes a power supply electrode 50a for applying a power supply voltage, a signal electrode 50b for outputting an electric signal corresponding to a received optical signal, and a light receiving unit 50c.
And The power supply electrode 50a is in contact with the electrode 15 or is electrically connected to the electrode 15 by being joined by solder or the like. Here, the power supply electrode 50a corresponds to a specific example of the “third power supply electrode” of the present invention, and the signal electrode 50b corresponds to a specific example of the “first signal output electrode” of the present invention.

On the surface of the insulating layer 20 (surface opposite to the substrate 11), for example, a signal electrode 16 to which an electric signal is applied from the outside, a signal electrode 17 for outputting an electric signal to the outside, Electrodes 18a, 18 to which power supply voltage is applied
b and other electrodes 19 are provided. A connection hole 13c is formed between the signal electrode 16 and the signal electrode 40b of the light emitting element 40, and the signal electrode 16 is connected to the connection hole 1b.
It is electrically connected to the signal electrode 40b via a conductor filled in 3c. A connection hole 13d is formed between the signal electrode 17 and the signal electrode 50b of the light receiving element 50, and the signal electrode 17 is electrically connected to the signal electrode 50b via a conductor filled in the connection hole 13d. ing. A connection hole 13 is provided between the electrode 18a and the electric wiring pattern 12c.
e is formed, and the electrode 18a is electrically connected to the electric wiring pattern 12c via a conductor filled in the connection hole 13e. A connection hole 13f is formed between the electrode 18b and the electric wiring pattern 12d, and the electrode 18b is electrically connected to the electric wiring pattern 12d via a conductor filled in the connection hole 13f. . Here, the signal electrode 16 corresponds to a specific example of the “second signal applying electrode” of the present invention, and the signal electrode 17 corresponds to a specific example of the “second signal output electrode” of the present invention. .

The optical waveguide 30 is provided between the light emitting element 40 and the light receiving element 50. The optical waveguide 30 has, for example, a reflective surface 3 having an obtuse angle (here, approximately 135 °) with the main surface of the electric wiring portion 10 at both ends in the longitudinal direction.
0a and 30b. The reflection surface 30a is the light emitting element 4
The optical signal is emitted from the light emitting unit 40c in the longitudinal direction in the optical waveguide 30. The reflecting surface 30b is located so as to face the light receiving portion 50c of the light receiving element 50, and reflects an optical signal propagating along the longitudinal direction in the optical waveguide 30 toward the light receiving portion 50c. I have. The external angle formed by the optical waveguide 30 and the surface of the electric wiring section 10 is the external angle of the figure when the cross section along the light propagation direction (longitudinal direction) of the optical waveguide 30 is considered to be a closed figure. Means In FIG. 1, the lower surface of the optical waveguide 30 is slightly separated from the upper surfaces of the light emitting element 40 and the light receiving element 50, but they may be in contact with each other.

As the electric wiring section 10, for example, a ceramic multilayer wiring board, an organic multilayer wiring board, a glass epoxy wiring board, a built-up multilayer wiring board, a printed wiring board and the like can be used. Here, the ceramic multilayer wiring board means that the substrate 11 is made of aluminum oxide (Al ₂
O _3), glass ceramics (e.g., low temperature fired glass ceramic), it refers to those constituted of an inorganic material containing at least one kind selected from the group consisting of aluminum (AlN) and mullite nitride. An organic multilayer wiring board is a board made of glass epoxy resin, polyimide, B
It is made of an organic material containing at least one selected from the group consisting of T resin, PPE (Polyphenyl ether) resin, phenol resin, and polyolefin resin (for example, Teflon (registered trademark) manufactured by DuPont). Note that, among the organic multilayer wiring substrates, those formed of film-like polyimide or the like are also called flexible multilayer wiring substrates. The glass epoxy multilayer wiring board means that the substrate 11 is made of a glass epoxy resin such as FR-4, and the built-up multilayer wiring board is, for example, a photosensitive or non-photosensitive resin on a normal glass epoxy wiring board. Although a high-density electrical wiring pattern is formed by a photolithography technique using a resin such as a photosensitive epoxy resin, a photosensitive or non-photosensitive polyimide, or a photosensitive or non-photosensitive benzocyclobutene (BCB), That means. In addition, a printed wiring board refers to a printed circuit board on which electric wiring patterns are printed at a high density on a core substrate made of, for example, a dielectric material.

The insulating layer 20 is made of, for example, an epoxy resin having a thickness of 100 μm. The optical waveguide 3
When 0 and the light emitting element 40 and the light receiving element 50 are arranged apart from each other, it is preferable that the insulating layer 20 is formed of a material transparent to an optical signal. This is because light propagation loss when an optical signal is transmitted can be suppressed.

The optical waveguide 30 has, for example, a refractive index of 1.5.
It is composed of about 4 bisphenol-based epoxy resin, and its thickness is, for example, 30 μm.

The optical waveguide 30 is not limited to the structure shown in FIG. 1, but may have another structure. For example, as shown in FIGS. 2A and 2B, a core layer 31 and a cladding layer 32 formed so as to surround the core layer 31.
The optical waveguide 30 </ b> A having a structure having the above structure may be used. Incidentally, FIG. 2A shows a cross-sectional structure of the optical waveguide 30A cut in the same direction as FIG. 1, and FIG.
Corresponds to a section taken along the line IIB-IIB in FIG.

In the optical waveguide 30A, the core layer 31 is made of, for example, an epoxy resin whose main material is bisphenol having a refractive index of about 1.54, and has a thickness of, for example, 30 μm. The core layer 31 has, for example, reflection surfaces 31a and 31b at both ends in the longitudinal direction. The cladding layer 32 is made of a material having a lower refractive index than the constituent material of the core layer 31, for example, an epoxy resin having a refractive index of about 1.52, and has a thickness of, for example, 30 μm. As described above, it is preferable to provide the optical waveguide 30A with a difference in the refractive index because the light propagation loss is small. Note that the cladding layer 32 and the core layer 31 may be made of acrylic resin such as polyimide, polymethyl methacrylate, polyethylene, polystyrene, or the like, as long as the condition that the refractive index of the core layer 31 is larger than that of the cladding layer 32 is satisfied. And other materials such as polyolefin resin or synthetic rubber.

The light emitting element 40 is constituted by, for example, a surface emitting type light emitting diode (LED). Here, the surface-emitting type refers to an element in which light is emitted from the main surface (the surface having the largest area) of the element. In addition, the light receiving element 50 is configured by, for example, a surface-emitting type photodiode. Here, the term “surface light receiving type” refers to a type that receives light by a main surface.

The optical wiring board having such a configuration is used, for example, as an optical wiring module as shown in FIG. This optical wiring module is provided, for example, on the opposite side of the insulating layer 20 of the optical wiring board shown in FIG.
IC chips 61 and 62 are provided. Electronic circuits such as a signal processing circuit and a memory circuit are integrated in the IC chips 61 and 62, respectively. Where I
The C chips 61 and 62 correspond to a specific example of the “integrated circuit” of the present invention.

The optical wiring board (insulating layer 2) of the IC chip 61
On the 0) side, bumps (conductive protrusions) 63 and 64 electrically connected to the IC chip 61 are provided. The bump 63 is in contact with the electrode 18a, and the bump 6
4 is in contact with the signal electrode 16. As a result, the IC chip 61 includes the bump 63, the electrode 18 a and the connection hole 13.
e through the electric conductor filled in the electric wiring pattern 12c
And the bumps 64, the signal electrodes 1
6 and a conductor filled in the connection hole 13c, and is electrically connected to the signal electrode 40b of the light emitting element 40.

On the other hand, bumps 65 and 66 electrically connected to the IC chip 62 are provided on the side of the optical wiring board (insulating layer 20) of the IC chip 62, respectively. Bump 6
5 is in contact with the electrode 18b, and the bump 66 is in contact with the signal electrode 17. As a result, the IC chip 62
The bump 65, the electrode 18b, and the conductor filled in the connection hole 13f are electrically connected to the electric wiring pattern 12d, and the bump 66, the signal electrode 17, and the conductor filled in the connection hole 13d. It is electrically connected to the signal electrode 50b of the light receiving element 50.

Next, a method of manufacturing the optical wiring module shown in FIG. 3 will be described with reference to FIGS.
4 to 8 respectively show the respective manufacturing steps of the method for manufacturing the optical wiring module.

First, as shown in FIG. 4, the substrate 11 on which the electric wiring patterns 12a to 12g are formed (ie,
An electric wiring section 10), a light emitting element 40 and a light receiving element 50 are prepared. The electric wiring portion 10 has, for example, an electrode 14 electrically connected to the electric wiring pattern 12a through the connection hole 13a and an electric connection to the electric wiring pattern 12b through the connection hole 13b. An electrode having the formed electrode 15 is prepared. After that, the power supply electrode 40a of the light emitting element 40 and the power supply electrode 14 on the surface of the electric wiring section 10 are joined by, for example, solder or the like.
The light emitting element 40 is mounted on the electric wiring section 10. Also,
The power supply electrode 50a of the light receiving element 50 and the power supply electrode 15 on the surface of the electric wiring section 10 are joined by, for example, solder, and the light receiving element 50 is mounted on the electric wiring section 10.

Next, as shown in FIG.
In addition, a lower insulating layer 20a is formed on the electric wiring section 10 so as to cover the light receiving element 50. This lower insulating layer 20a
Is formed, for example, by applying an epoxy resin by a roll coating method, a curtain coating method, a spin coating method or a dip coating method, and performing a heat treatment. Thereby, the light emitting element 40 and the light receiving element 50 are embedded in the lower insulating layer 20a. After forming the lower insulating layer 20a, the surface of the lower insulating layer 20a is planarized.

Next, as shown in FIG. 6, for example, one end in the longitudinal direction corresponds to the light emitting section 40c of the light emitting element 40, and the other end corresponds to the light receiving section 50c of the light receiving element 50. The optical waveguide 30 is formed as follows.

That is, when forming the optical waveguide 30, first, a liquid epoxy resin having a refractive index of about 1.54 after curing by, for example, spin coating is applied on the lower insulating layer 20a to a thickness of about 30 μm. After that, a photomask (not shown) is positioned and placed on the applied epoxy resin. The photomask includes, for example, a light-shielding film provided with an opening corresponding to the optical waveguide 30, and the thickness of the light-shielding film gradually decreases along the longitudinal direction of the opening, so that the vicinity of the short side of the opening of the light-shielding film is reduced. It is possible to use one in which the region functions as a gray scale region that transmits an amount of light according to the thickness of the light-shielding film.

After arranging the photomask, light is irradiated from the photomask side to the electric wiring section 10 side. This light irradiation is performed, for example, by using an ultra-high pressure mercury lamp for 10 minutes.
This is performed over a long time (for example, 3 minutes) at a low output of about mW / cm ² . After that, the uncured portion of the epoxy resin that is not irradiated with light is dissolved and removed using, for example, an organic solvent. Thus, the optical waveguide 30 is formed, and the reflection surfaces 30a and 30b are formed at both ends.

An optical waveguide 30A having a core layer 31 and a cladding layer 32 as shown in FIGS.
Is formed as follows. First, a liquid epoxy resin having a refractive index of about 1.52 after curing by, for example, spin coating is applied on the lower insulating layer 20a.
After being applied so as to have a thickness of about 0 μm, for example, heat treatment is performed to cure the resin, and the lower clad layer 32 a
(See FIG. 2A). Next, on the lower cladding layer 32a, for example, using the same method as the above-described method of forming the optical waveguide 30, the reflection surfaces 31a, 31 are formed on both ends.
The core layer 31 having b is formed. Subsequently, on the exposed surface of the lower cladding layer 32a and on the core layer 31, a liquid epoxy resin having a refractive index of about 1.52 after curing by, for example, spin coating is applied to the upper part of the core layer 31 to a thickness of 30 μm.
After being applied to a thickness of about the same, heat treatment is performed to solidify the resin, thereby forming the upper cladding layer 32b.

After the formation of the optical waveguide 30, as shown in FIG.
b is formed. The upper insulating layer 20b is formed using, for example, the same material and the same method as the lower insulating layer 20a. Thereby, the lower insulating layer 20a and the upper insulating layer 2
0b is formed.

Next, as shown in FIG. 8, connection holes 13c to 13f are formed in the insulating layer 20 corresponding to the electric wiring patterns 12c and 12d and the signal electrodes 40b and 50b, respectively. Thereafter, a conductor such as copper is embedded in the connection holes 13c to 13f by, for example, a plating method or a printing method, and the signal electrodes 16, 17 and the electrodes 18a,
18b are formed respectively. The connection holes 13c to 13c
The formation of f is performed using, for example, a laser or a drill. When the insulating layer 20 is formed of a photosensitive material, the connection holes 13c to 13f can be formed using photolithography.

Next, bumps 63 and 64 are formed on the IC chip 61.
And bumps 65 and 66 are attached to the IC chip 62, respectively. After that, the IC chips 61 and 62 are mounted on the insulating layer 20 by, for example, a flip chip bonding method using the bumps 63 to 66. Thus, the optical wiring module shown in FIG. 3 is completed.

Next, the operation of the optical wiring module will be described.

In this optical wiring module, when a power supply voltage applied from the outside is applied to the power supply electrode 40a of the light emitting element 40 via the electric wiring pattern 12a and the electrode 14 of the electric wiring section 10, the light emitting element 40 is turned on. Operable state. Further, the power supply voltage applied from the outside is applied to the light receiving element 50 via the electric wiring pattern 12b and the electrode 15.
Is applied to the power supply electrode 50a, the light receiving element 50 becomes operable. Further, the electric wiring patterns 12c,
When a power supply voltage is applied to the IC chips 61 and 62 via the electrode 12d, the electrodes 18a and 18b, and the bumps 63 and 65, the IC chips 61 and 62 become operable.

When an electric signal is output from a signal pad (not shown) of the IC chip 61 in a state where the light emitting element 40, the light receiving element 50, and the IC chips 61 and 62 are operable, the light emitting element 40 is Signal electrode 40
b, an electric signal is input, the light emitting element 40 converts the electric signal into an optical signal, and emits an optical signal from the light emitting unit 40c. The emitted optical signal enters the optical waveguide 30 and its reflection surface 3
At 1a, the light is totally reflected, for example, in a direction substantially perpendicular to the incident direction and enters the inside of the core layer 31. After that, this optical signal propagates in the core layer 31 and reaches the reflection surface 31b. Here, the optical signal is totally reflected, for example, in a direction substantially perpendicular to the light propagation direction, exits the optical waveguide 30, and enters the light receiving unit 50 c of the light receiving element 50. The optical signal incident on the light receiving element 50 is converted into an electric signal and is converted into a signal electrode 50b.
From the IC chip 62 via the signal electrode 17
Are input to a signal pad (not shown). Thus, the optical signal is transmitted at high speed between the IC chip 61 and the IC chip 62. Also, signals that may be transmitted at a relatively low speed, such as low-speed control signals, are transmitted as electrical signals by a predetermined electrical wiring pattern. Here, since the optical waveguide 30 is provided inside the insulating layer 20,
Damage to the optical waveguide 30 is prevented, and light propagation loss is reduced.

As described above, according to the optical wiring board according to the present embodiment, the optical waveguide 30 as the optical wiring is disposed inside the insulating layer 20. Can be effectively prevented. Therefore, disconnection of the optical wiring can be prevented. In addition, the influence of optical noise can be eliminated. Further, light propagation loss can be reduced. Therefore, by using this optical wiring board, it is possible to configure an optical wiring module having excellent light propagation characteristics. Also, high-speed transmission of signals becomes possible.

Further, if the light emitting element 40 and the light receiving element 50 are also provided inside the insulating layer 20, they are also protected and the light propagation characteristics can be further improved.

When an optical wiring module is formed using the optical wiring board according to the present embodiment, the IC chips 61 and 6 are formed on the optical wiring board as compared with the case where the optical wiring is exposed.
Since the area in which electrical components such as No. 2 or other chip components can be mounted increases, the degree of freedom at the time of design increases, and these components can be easily mounted.

(First Modification) FIG. 9 shows a partially cut away structure of an optical wiring module according to a first modification of the first embodiment of the present invention. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The optical wiring module according to this modification is significantly different from the optical wiring module of the first embodiment in that the optical waveguide 30B, the light emitting element 40 and the light receiving element 50 are electrically connected on the electrical wiring section 10. That is, they are arranged in this order from the wiring section 10 side. Therefore, here, the optical waveguide 30B has, for example, reflection surfaces 30c and 30d at both ends where the outer angle with the main surface of the electric wiring portion 10 is an acute angle (here, approximately 45 °).

In this optical wiring module, a signal electrode 71 to which an electric signal is applied from the signal electrode 16 and a signal electrode 72 for outputting an electric signal to the signal electrode 17 are provided on the surface of the insulating layer 20. .

A connection hole 13g is formed between the signal electrode 71 and the signal electrode 16, and the signal electrode 71 and the signal electrode 16 are electrically connected via a conductor filled in the connection hole 13g. ing. A bump 7 is formed on the surface of the signal electrode 71.
3 are provided, and the signal electrode 71 is electrically connected to the signal electrode 40 b of the light emitting element 40 via the bump 73. An electrode 14A to which a power supply voltage is applied from the outside is provided on the surface of the insulating layer 20. Electrode 14A
Connection hole 13 between the power supply electrode 40a of the light emitting element 40
h is formed, and the electrode 14A is electrically connected to the power supply electrode 40a via a conductor filled in the connection hole 13h. The electrode 14A is electrically connected to the electric wiring pattern 12a via a conductor filled in a connection hole (not shown).

A connection hole 13i is formed between the signal electrode 72 and the signal electrode 17, and the signal electrode 72 and the signal electrode 17 are electrically connected via a conductor filled in the connection hole 13i. ing. The bump 7 is formed on the surface of the signal electrode 72.
The signal electrode 72 is electrically connected to the signal electrode 50 b of the light receiving element 50 via the bump 74. An electrode 15A to which a power supply voltage is applied from the outside is provided on the surface of the insulating layer 20. Electrode 15A
Connection hole 13 between power supply electrode 50a of
j is formed, and the electrode 15A is electrically connected to the power supply electrode 50a via a conductor filled in the connection hole 13j. The electrode 15A is electrically connected to the electric wiring pattern 12b via a conductor filled in a connection hole (not shown).

In the optical wiring module having such a configuration, when an electric signal is output from a signal pad (not shown) of the IC chip 61, the signal electrode 16 and the signal electrode 71 are output.
An electric signal is input to the signal electrode 40b of the light emitting element 40 via the. The optical signal incident on the light receiving element 50 is converted into an electric signal and output from the signal electrode 50b, and is transmitted through the signal electrode 72 and the signal electrode 17 to the IC chip 62.
Is input to the signal pad. The rest operates in the same manner as in the first embodiment. Further, the optical wiring module according to the present modification has the same effects as those of the first embodiment.

(Second Modification) FIG. 10 shows a first modification of the present invention.
13 shows a partially cutaway structure of an optical wiring module according to a second modification of the embodiment. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The optical wiring module according to this modification is significantly different from the optical wiring module of the first embodiment in that an edge emitting type light emitting element 40 and a surface receiving type light receiving element 50 are used instead of the surface emitting type light emitting element 40 and the surface receiving type light receiving element 50. Is provided with the light emitting element 40A and the end face light receiving type light receiving element 50A. Therefore, here, it is not necessary to provide reflection surfaces at both ends of the optical waveguide 30C, and the optical waveguide 30C has, for example, a rectangular cross section. In the optical waveguide 30C, the light emitting element 40A, and the light receiving element 50A, one side surface of the optical waveguide 30C and the light emitting section 40c of the light emitting element 40A, and the other side surface of the optical waveguide 30C face the light receiving section 50c of the light receiving element 50A. It is arranged as follows.

The optical wiring module having such a configuration operates and has the same effect as the optical wiring module of the first embodiment. Further, as described above, since it is not necessary to provide reflection surfaces at both ends of the optical waveguide 30B,
It has the advantage that it can be easily manufactured.

[Second Embodiment] First, a second embodiment of the present invention will be described.
The configuration of the optical wiring module according to the embodiment will be described. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 11 shows the structure of the optical wiring module according to the present embodiment in a partially broken manner. This optical wiring module is largely different from the optical wiring module according to the first embodiment in that the light emitting element 40 and the light receiving element 5
0 is not embedded in the insulating layer 20 and the insulating layer 2
0.

The light emitting element 40 is, for example, an IC chip 61
On the side facing the optical wiring substrate (insulating layer 20), the light emitting portion 40c is disposed so as to correspond to the reflection surface 30c of the optical waveguide 30B. The signal electrode 40b of the light emitting element 40
The IC chip 61 is in contact with a signal pad (not shown) of the IC chip 61 or is joined by solder or the like.
Is electrically connected to The power supply electrode 40a is
It is electrically connected to the electric wiring pattern 12a via a conductor filled in a connection hole (not shown).

On the other hand, the light receiving element 50 is arranged, for example, on the side of the IC chip 62 facing the optical wiring board so that the light receiving portion 50c corresponds to the reflection surface 30d of the optical waveguide 30B. The signal electrode 50b of the light receiving element 50 is in contact with a signal pad (not shown) of the IC chip 62, or is electrically connected to the IC chip 62 by being joined by solder or the like. The power supply electrode 50a is electrically connected to the electric wiring pattern 12b via a conductor filled in a connection hole (not shown).

In the optical wiring module having such a configuration, for example, the electric wiring section 10 is prepared, and the lower insulating layer, the optical waveguide 30B, and the upper insulating layer are sequentially formed in the same manner as in the first embodiment. Later, an IC mounting the light emitting element 40
Chip 61 and IC chip 62 on which light receiving element 50 is mounted
Can be manufactured by mounting.

As described above, the light emitting element 40 and the light receiving element 5
Even when 0 is not embedded in the insulating layer 20, similarly to the first embodiment, disconnection of the optical wiring and generation of optical noise can be prevented, and light propagation loss can be reduced. be able to.

[Third Embodiment] The present embodiment relates to a method for manufacturing an optical wiring board and a method for manufacturing an optical wiring module in which an optical waveguide formed separately in advance is transferred onto the electric wiring section 10. Things. FIGS. 12 and 13 show the respective manufacturing steps of the method for manufacturing the optical wiring module.

In this embodiment, first, as shown in FIG. 12, for example, a transparent dummy substrate 81 having excellent flatness is formed.
And a substrate separation layer 82 of 500 nm thick made of silicon dioxide (SiO ₂ ) is formed on the dummy substrate 81 by, for example, a plasma CVD (Chemical Vapor Deposition) method. Next, a liquid epoxy resin having a refractive index of about 1.54 after curing is applied to the substrate separation layer 82 so as to have a thickness of about 30 μm by, for example, a spin coating method. A photomask (not shown) is positioned and arranged. As the photomask, for example, a photomask similar to that described in the first embodiment can be used.

After arranging the photomask, light is irradiated from the photomask side to the electric wiring section 10 side. This light irradiation is performed, for example, by using an ultra-high pressure mercury lamp for 10 minutes.
The operation is performed for 3 minutes at an output of about mW / cm ² . Here, since an epoxy resin having a small amount of light absorption and an excellent transmittance is used, light reflected on the front and back surfaces of the dummy substrate 81 is also considered to contribute to the exposure. Therefore, the exposed area of the epoxy resin is hardened from the back side and fixed to the substrate separation layer 82. At this time, the portion of the photomask (specifically, the light shielding film) corresponding to the gray scale region is cured from the lower layer side, and the upper layer side is not cured.
After the light irradiation, an uncured portion of the epoxy resin that is not irradiated with the light is dissolved and removed using, for example, an organic solvent. As a result, the optical waveguide 30 is formed, and reflection surfaces 30a and 30b are formed at both ends of the dummy substrate 81, the outer angles of which are acute angles (here, approximately 45 °).

Next, as shown in FIG. 13, the optical waveguide 30 formed on the dummy substrate 81 is brought into close contact with the lower insulating layer 20a while performing alignment. At this time, an adhesive layer 83 made of epoxy resin or the like is arranged between the optical waveguide 30 and the lower insulating layer 20a. 12 and 13, for convenience, the optical waveguide 3
0 is shown on a different scale.

Subsequently, the lower insulating layer 20a and the dummy substrate 8
1 and the optical waveguide 30 in close contact with each other, for example,
Light is irradiated from the dummy substrate 81 side toward the electric wiring section 10 at an output of 10 mW / cm ² for 3 minutes using an ultra-high pressure mercury lamp. As a result, the epoxy resin forming the adhesive layer 83 is cured, and the optical waveguide 30 is moved to the lower insulating layer 20 a
At a desired position. Note that the adhesive layer 83 may be cured by heat treatment.

Next, while the lower insulating layer 20a is fixed to the optical waveguide 30, the dummy substrate 81 is placed on a thin hydrogen fluoride (HF) solution or a buffered hydrogen fluoride (BH).
F; Buffered HF) Immerse in solution. Thereby, the substrate separation layer 82 formed between the dummy substrate 81 and the optical waveguide 30 is dissolved and removed, and the dummy substrate 8 on the substrate separation layer 82 is removed.
1 is separated from the optical waveguide 30 (lift-off), and the optical waveguide 30 is moved to the electrical wiring section 10 side (specifically,
Transferred onto the lower insulating layer 20a). The subsequent steps are the same as in the first embodiment.

As described above, in the present embodiment, the optical waveguide 3
0 is formed on the dummy substrate 81 having excellent flatness,
Since the transfer is performed on the upper insulating layer 20, when forming the optical waveguide 30A, the base (here, the lower insulating layer 20) is formed.
Even when the surface of (a) has irregularities, the optical waveguide 30 having a small light propagation loss can be formed without being affected by the irregularities.

As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments, and can be variously modified. For example, the first and third
In the second embodiment, the case where both the light emitting element 40 and the light receiving element 50 are embedded in the insulating layer 20 will be described. In the second embodiment, both the light emitting element 40 and the light receiving element 50 will be Has been described, but only one of the light receiving element 40 and the light emitting element 50 may be embedded in the insulating layer 20. For example, as shown in FIG. 14, when the light emitting element 40 is provided inside the insulating layer 20 and the light receiving element 50 is provided outside the insulating layer 20, A reflecting surface 30a having an obtuse angle (eg, approximately 135 °) with respect to the main surface of the light-emitting device 10;
An optical waveguide 30D having a reflection surface 30d facing the light receiving portion 50c and having an acute angle (for example, approximately 45 °) with the main surface of the electric wiring portion 10 at both ends in the longitudinal direction may be used. .

Further, in the third embodiment, the optical waveguide 30 composed of only the core layer is transferred onto the electric wiring section 10, but the core layer 31 and the core layer 31 shown in FIG. It is also possible to transfer the optical waveguide 30A composed of the cladding layer 32. Further, in the third embodiment, a case has been described in which an optical wiring module having the same configuration as that of the first embodiment is manufactured. However, an optical module having the same configuration as that of the second embodiment is described. The present invention can be applied to a case where a wiring module is manufactured.

Further, in the first embodiment, the optical wiring board constituted by the electric wiring section 10 and the insulating layer 20 in which the optical waveguide 30, the light emitting element 40 and the light receiving element 50 are embedded has been described. The optical wiring board does not necessarily need to include the light emitting element 40 and the light receiving element 50. Even in that case, the effect of disposing the optical waveguide 30 inside the insulating layer 20 can be obtained.

In each of the above embodiments, the insulating layer 2
Although the case where the IC chips 61 and 62 are mounted on 0 has been described, other circuits and components can be mounted.

In addition, in each of the above embodiments, the insulating layer 2
0, only one optical waveguide is arranged inside.
It is also possible to laminate a plurality of optical waveguides in the same direction as the laminating direction of the electric wiring patterns 12a to 12g to realize a multilayer optical wiring.

[0076]

As described above, according to the optical wiring board according to any one of claims 1 to 14, or the optical wiring module according to any one of claims 15 to 18, Since the optical waveguide is arranged inside the base having the electric wiring pattern, high-speed transmission by an optical signal is possible, and damage to the optical waveguide due to external impact can be effectively prevented. It works.

A method for manufacturing an optical wiring board according to any one of claims 19 to 21 or claim 2.
According to the method for manufacturing an optical wiring module according to any one of claims 2 to 24, the lower insulating layer is formed, the optical waveguide is formed thereon, and the upper insulating layer is further formed so as to cover the optical waveguide. By forming, the optical waveguide is embedded in the insulating layer, so that the optical wiring board or the optical wiring module of the present invention can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an optical wiring board according to a first embodiment of the present invention.

FIG. 2 is a sectional view illustrating a modification of the optical waveguide illustrated in FIG.

FIG. 3 is a side view showing a configuration of the optical wiring module according to the first embodiment of the present invention, partially cut away;

FIG. 4 is a cross-sectional view for explaining a method of manufacturing the optical wiring module shown in FIG.

FIG. 5 is a cross-sectional view for explaining a step following the step shown in FIG. 4;

FIG. 6 is a cross-sectional view for explaining a step following the step shown in FIG. 5;

FIG. 7 is a cross-sectional view for explaining a step following the step shown in FIG. 6;

FIG. 8 is a cross-sectional view for explaining a step following the step shown in FIG. 7;

FIG. 9 is a side view showing an optical wiring module configuration according to a first modification of the optical wiring module shown in FIG.

FIG. 10 is a side view showing an optical wiring module configuration according to a second modification of the optical wiring module shown in FIG.

FIG. 11 is a partially cutaway side view illustrating a configuration of an optical wiring module according to a second embodiment of the present invention.

FIG. 12 is a cross-sectional view for explaining the method for manufacturing the optical wiring module according to the third embodiment of the present invention.

FIG. 13 is a cross-sectional view for explaining a step following the step shown in FIG. 12;

FIG. 14 is a partially cutaway side view showing an optical wiring module configuration according to another modification of the optical wiring module shown in FIG. 3;

[Explanation of symbols]

Reference numeral 10: electric wiring portion, 11: substrate, 12a to 12g: electric wiring pattern, 13a to 13j: connection holes, 14, 14
A, 15, 15A, 18a, 18b, 19 ... electrodes, 1
6, 17, 40b, 50b, 71, 72 ... signal electrodes, 2
0: insulating layer, 20a: lower insulating layer, 20b: upper insulating layer, 30, 30A to 30D: optical waveguide, 30a to 30
d, 31a, 31b: reflective surface, 31: core layer, 32: clad layer, 40, 40A: light emitting element, 40a, 50a ...
Power supply electrode, 40c: light emitting unit, 50, 50A: light receiving element,
50c: light receiving section, 61, 62: IC chip, 63-6
6, 73, 74: bump, 81: dummy substrate, 82: substrate separation layer, 83: adhesive layer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05K 3/46 G02B 6/12 M H01L 31/02 C F term (reference) 2H047 KA03 MA07 PA02 PA22 PA24 PA28 QA05 5E346 AA42 AA43 BB02 BB03 BB16 BB20 CC08 CC09 CC10 CC13 CC16 DD03 DD32 EE31 FF18 FF45 HH40 5F088 AA02 BA13 BA18 DA01 FA09 FA11 FA20 JA01 JA05 JA11 JA20 5F089 AA06 AB03 AC02 AC05 AC08 AC09 AC10 AC16 AC18 CA20 EA10

Claims (24)

[Claims] 1. An optical wiring board comprising: a base having an electric wiring pattern; and an optical waveguide disposed inside the base so as to transmit an optical signal. 2. The optical wiring board according to claim 1, further comprising a light emitting element for transmitting an optical signal and a light receiving element for receiving the optical signal. 3. The optical wiring board according to claim 1, wherein the base includes an electric wiring portion on which an electric wiring pattern is formed, and an insulating layer covering the electric wiring portion. 4. The optical wiring board according to claim 3, wherein the optical waveguide is provided inside the insulating layer. 5. A light-emitting element for transmitting an optical signal, and a light-receiving element for receiving an optical signal, wherein at least one of the light-emitting element and the light-receiving element includes:
The optical wiring board according to claim 4, wherein the optical wiring board is provided inside the insulating layer. 6. The light emitting element has a first signal applying electrode for applying an electric signal, and a second signal applying electrode to which an electric signal is applied from the outside is provided on a surface of the insulating layer. The optical wiring board according to claim 5, wherein the first signal applying electrode and the second signal applying electrode are electrically connected. 7. The light emitting element further includes a first power supply electrode for applying a power supply voltage, and the electric wiring unit has a second power supply voltage applied from the outside.
7. The optical wiring board according to claim 6, further comprising: a first power supply electrode and the second power supply electrode. 8. The light receiving element has a first signal output electrode for outputting an electric signal corresponding to a received optical signal, and on the surface of the insulating layer, for outputting an electric signal to the outside. 6. The optical wiring board according to claim 5, wherein a second signal output electrode is disposed, and the first signal output electrode and the second signal output electrode are electrically connected. 9. The light receiving element further includes a third power supply electrode for applying a power supply voltage, and the electric wiring unit has a fourth power supply voltage to which a power supply voltage is externally applied.
9. The optical wiring board according to claim 8, wherein the third power electrode and the fourth power electrode are electrically connected. 10. 10. The optical wiring board according to claim 1, wherein the optical waveguide includes a core layer for transmitting light, and a clad layer surrounding the core layer. 11. The optical wiring board according to claim 1, wherein said optical waveguide is made of a material containing at least one of a group consisting of polyimide, epoxy resin, acrylic resin, polyolefin resin and synthetic rubber. . 12. The optical wiring board according to claim 3, wherein said electric wiring portion includes a plurality of electric wiring patterns. 13. The electric wiring part according to claim 1, wherein the electric wiring pattern is formed on a substrate made of an inorganic material containing at least one of a group consisting of aluminum oxide, glass ceramic, aluminum nitride, and mullite. The optical wiring board according to claim 3, wherein: 14. The electric wiring part is made of glass epoxy resin, polyimide, BT resin, PPE (Polyphenyl ether).
4. The optical wiring board according to claim 3, wherein an electrical wiring pattern is formed on a substrate made of an organic material containing at least one of a group consisting of resin, phenol resin and polyolefin resin. 15. A base having an electric wiring pattern, an optical waveguide disposed inside the base so as to transmit an optical signal, a light emitting element for transmitting an optical signal, and a light emitting element for receiving an optical signal. An optical wiring module comprising: a light receiving element; and an integrated circuit that transmits and receives an electric signal between at least one of the light emitting element and the light receiving element. 16. The optical wiring module according to claim 15, wherein the base includes an electric wiring portion on which an electric wiring pattern is formed, and an insulating layer covering the electric wiring portion. 17. The optical wiring module according to claim 16, wherein said optical waveguide is provided inside said insulating layer. 18. The optical wiring module according to claim 16, wherein at least one of said light emitting element and said light receiving element is disposed inside said insulating layer. 19. A step of forming a lower insulating layer on an electric wiring portion on which an electric wiring pattern is formed, and a step of forming an optical waveguide capable of transmitting an optical signal on the lower insulating layer. And a step of forming an upper insulating layer so as to cover at least the optical waveguide. 20. The step of forming the optical waveguide includes: forming the optical waveguide on a predetermined dummy substrate; and transferring the optical waveguide formed on the dummy substrate onto the upper insulating layer. 20. The method for manufacturing an optical wiring board according to claim 19, comprising: 21. The method of claim 19, further comprising forming at least one of a light emitting element and a light receiving element so as to be covered by the upper insulating layer or the lower insulating layer. Method. 22. A step of forming a lower insulating layer on an electric wiring portion having an electric wiring pattern formed thereon, and a step of forming an optical waveguide capable of transmitting an optical signal on the lower insulating layer. Forming an upper insulating layer so as to cover at least the optical waveguide; forming a light emitting element for transmitting an optical signal and a light receiving element for receiving the optical signal; Forming an integrated circuit for transmitting and receiving an electric signal to and from at least one of the light emitting element and the light receiving element. 23. The optical wiring module according to claim 22, wherein at least one of the light emitting element and the light receiving element is formed so as to be embedded in the upper insulating layer or the lower insulating layer. Production method. 24. The light-emitting element and the light-receiving element,
The method according to claim 22, wherein the optical wiring module is formed on the upper insulating layer.