JP2002333537A - Optical wave guide circuit and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin optical wave guide circuit at a low cost and a method for manufacturing the same. SOLUTION: At least part of side surfaces of waveguides 6 formed with a light transmissivity materials is covered with reflective layers 7, this is embedded in insulated substrates 8 and 9, and is made to paths for optical signals. Electrical wiring patterns are arranged in a surface and an inside of the insulated substrate 8 and/or the insulated substrate 9, and the waveguides 6 and the electrical wiring patterns coexist in the insulated substrates 8 and 9. An electric current is made to flow through the reflective layers 7 as part of the electrical wiring patterns, and the entire thickness of optical waveguide circuit can be made thin and the degree of integration can be improved by coexistence of the waveguides and the electrical wiring patterns combined with the use of the reflective layers 7 as the electrical wiring patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide circuit having a waveguide, and more particularly, to an optical waveguide circuit having both a waveguide and a conductive wiring pattern.

[0002]

2. Description of the Related Art With the rapid development of IT (information technology),
The development of optical communication networks using fiber optic cables that can transmit large-capacity signals at high speeds over long distances without attenuating signals is expanding, and the signals transmitted in the form of optical signals are read and converted to electrical signals. There is a demand for the development of a semiconductor device that performs processing. FIG. 13 is a vertical sectional view of a typical optical communication-compatible semiconductor device. In such an optical communication-compatible semiconductor device 100, an optical wiring layer 101 for flowing an optical signal, an optical semiconductor element 102 for receiving and performing arithmetic processing on the optical signal, and converting this into an electric signal, An electric wiring layer 103 such as a wiring pattern for sending out an electric signal from 102 and a power supply line for supplying necessary power to a semiconductor element is provided.

In a semiconductor device 100 compatible with optical communication, an optical wiring for transmitting an optical signal transmitted through an optical communication network to a semiconductor element, and a semiconductor element 101 for performing arithmetic processing based on the received optical signal are provided. Since an electric wiring for extracting an electric signal output from the semiconductor element 101 and an electric wiring such as a power supply line for supplying electric power for driving the semiconductor element are required, a substrate on which the semiconductor element 101 is mounted is required. Two wiring layers 101 and 10 for optical wiring and electric wiring
3 is required.

[0004] By the way, a waveguide 104 which becomes a path of light.
The outer surface of a linear member made of a transparent material, which is generally called a "core material" and easily transmits light, is covered with a material called a "cladding material" having a lower refractive index than the core material. In this structure, the light is transmitted while maintaining the signal intensity by total reflection. Both the core material 104 and the clad material 105 are often insulative, such as inorganic materials and resins.
Therefore, it is necessary to provide the optical semiconductor element 102 with the electric wiring layer 103 using a conductive material such as a metal in addition to the optical wiring layer 101 including the core material 104 and the clad material 105.
For example, in the device 100 of FIG. 13, an optical wiring layer 101 composed of a clad material 105 and a core material 104 is disposed immediately below a semiconductor element 102, and an insulating substrate 106 is formed below the optical wiring layer 101. An electric wiring pattern 107 made of a metal foil is provided, and conduction between the electric wiring pattern 107 and the optical semiconductor element 102 is established by an electric wiring layer 103.
And the optical wiring layer 101 are formed by via holes 108 penetrating in the thickness direction thereof.

[0005]

However, in the structure in which the optical wiring layer and the electric wiring layer are separately formed and arranged adjacent to each other as shown in FIG. And the electrical resistance increases. Further, when the optical wiring layer 101 is disposed immediately below the optical semiconductor element 102 as shown in FIG.
It is necessary to use a heat-resistant core material or a clad material capable of withstanding the heat generated from Step 2, and it is necessary to use expensive materials such as polyimide. There is a problem above. The present invention is an invention created to solve the above-mentioned conventional problems.
That is, an object of the present invention is to provide an optical waveguide circuit having a low thickness at a low cost and a method for manufacturing the same.

[0006]

An optical waveguide circuit according to the present invention comprises:
An insulating substrate, a waveguide disposed in the insulating substrate and formed of a light transmissive material, and a reflective layer covering at least a part of an outer peripheral surface of the waveguide are provided. In the above-mentioned optical waveguide circuit, a single layer or a plurality of layers of conductive wiring patterns interconnected with each other may be provided on the surface and / or inside the insulating substrate. Further, in the above-mentioned optical waveguide circuit, an example of the reflection layer includes a reflection layer made of a conductive material and constituting a part of the conductive wiring pattern. Further, in the above-described optical waveguide circuit, examples of the light-transmitting material include an organic material and a gas.
In the optical waveguide circuit, the insulating substrate may be a flexible substrate.

[0007] A method of manufacturing an optical waveguide circuit according to the present invention comprises the steps of forming a first metal layer on a base film, forming a masking layer on the first metal layer, and patterning the masking layer. Forming a groove-shaped waveguide pattern corresponding to the waveguide, forming a second metal layer on the bottom of the waveguide pattern, and filling the second metal layer with a light-transmitting material. Forming a waveguide, removing the masking layer, forming a third metal layer covering the first metal layer, side surfaces of the second metal layer, and the surface of the waveguide; Forming an insulating material layer on the third metal layer, removing the base film, and removing the first metal layer while leaving the third metal layer and the second metal layer covering the outer periphery of the waveguide. Layer, the second metal layer and the third metal layer. Removing a part of the metal layer and exposing an insulating material layer; and providing a protective insulating layer on the third metal layer and the second metal layer covering the outer periphery of the waveguide and the exposed insulating material layer. Forming a material layer.

According to another method of manufacturing an optical waveguide circuit of the present invention, a step of forming a first metal layer on a base film, a step of forming a masking layer on the first metal layer, and patterning the masking layer Forming a groove-shaped waveguide pattern corresponding to the waveguide, filling the waveguide pattern with a light-transmitting material to form a waveguide, removing the masking layer, Forming a first metal layer and a second metal layer covering the surface of the waveguide; forming an insulating material layer on the second metal layer; and forming a second metal layer on the second metal layer. Forming a protective insulating material layer.

[0009] Still another method of manufacturing an optical waveguide circuit according to the present invention includes a step of forming a first metal layer on a base film;
Forming a masking layer on the first metal layer, patterning the masking layer to form a groove-shaped waveguide pattern corresponding to a waveguide, and filling the waveguide pattern with a light transmitting material Forming a waveguide, removing the masking layer, and forming a protective insulating material layer on the surface of the first metal layer and the waveguide.

[0010] Still another method of manufacturing an optical waveguide circuit according to the present invention includes a step of forming a first metal layer on a base film; a step of forming a photosensitive material layer on the first metal layer; Exposing a waveguide equivalent portion or a non-waveguide equivalent portion of a photosensitive material layer to form a waveguide pattern, and developing the exposed photosensitive material layer to form a waveguide; and Forming a first metal layer and a second metal layer covering the surface of the waveguide; forming an insulating material layer on the second metal layer; and protecting the second metal layer on the second metal layer Forming an insulating material layer for use.

[0011] Still another method of manufacturing an optical waveguide circuit according to the present invention includes a step of forming a first metal layer on a base film; a step of forming a masking layer on the first metal layer; Patterning a masking layer to form a groove-shaped waveguide pattern corresponding to a waveguide, forming a second metal layer on the bottom of the waveguide pattern, and forming a light-transmitting material on the second metal layer. Forming a waveguide by filling the first metal layer, removing the masking layer, and forming an insulating material layer covering the side surfaces of the first metal layer, the second metal layer, and the surface of the waveguide. Removing the base film, removing the first metal layer while leaving the second metal layer covering the bottom of the waveguide, and exposing the insulating material layer and the second metal layer. And covers the bottom of the waveguide. And a step of forming an insulating material layer for protection on the second metal layer and the exposed insulating material layer.

According to the present invention, a conductive reflection layer is provided around the waveguide, and the reflection of the reflection layer prevents the attenuation of the optical signal. Therefore, the waveguide is not covered with the cladding material. Can be formed. As a result, the thickness of the optical waveguide circuit can be reduced. Further, by using this reflective layer as a part of the wiring pattern, both the optical signal and the electric signal can be transmitted by the waveguide according to the present invention, and the degree of integration of the entire optical waveguide circuit can be increased.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described. FIG. 1 is a flowchart of a method of manufacturing an optical waveguide circuit according to the present embodiment, FIG. 2 is a vertical sectional view of the optical waveguide circuit according to the present embodiment during manufacture, and FIG. 3 is an optical waveguide circuit according to the present embodiment. It is a perspective view of a circuit.

To manufacture the optical waveguide circuit 1 according to the present embodiment, first, a base film 2 as shown in FIG. 2A is prepared (step 1). As the base film 2, various resins that can be formed into a film, such as polyimide, PET, PEN, and polyethylene, can be used.

Next, a metal layer 3 as a first metal layer is formed on one surface of the base film 2 by plating, sputtering or other known method (step 2). Next, a masking layer 4 is formed on the first metal layer 3. As the masking layer 4, for example, a photosensitive resin can be used. In this case, masking is performed according to a predetermined waveguide pattern, exposure is performed from above, the waveguide pattern is transferred to a photosensitive resin layer, and development is performed to remove unnecessary portions, as shown in FIG. A groove 41 corresponding to such a waveguide pattern is formed (step 3). Next, the bottom of the groove 41 formed corresponding to this waveguide pattern is plated or sputtered or other known method as shown in FIG.
As shown in (d), a metal layer 5 as a second metal layer is formed (Step 4). Next, as shown in FIG. 2E, the light transmitting material 61 is filled on the second metal layer 5 formed at the bottom of the groove 41 to form the waveguide 6 (Step 5). As the light transmitting material 61 used here, for example, 1.3 to 1.5 μm wavelength of epoxy resin, acryl, fluorinated acryl, polycarbonate, polybutadiene, 4-methylpentene 1 polyarylate, fluorinated polyimide, polystyrene, polyurethane, etc. Various resins having high light transmittance to the light can be used.

After the waveguide 6 has been formed, the masking layer 4
To expose the side surface of the waveguide 6, the side surface of the second metal layer 5, and the surface of the first metal layer 2 as shown in FIG. 2F (step 6). Next, as shown in FIG. 2 (g), the exposed side surface of the waveguide 6, the side surface of the second metal layer 5, and the surface of the first metal layer 2 are plated, sputtered, or another known method. Then, a third metal layer 7 is formed (Step 7). Next, as shown in FIG. 2H, a top coat layer 8 as an insulating material layer is formed on the third metal layer 7 (Step 8).

The resin for the top coat layer 8 is not particularly limited, but a resin which is liquid and solidifies by desolvation or crosslinking reaction after coating is preferred because it is easy to handle. As an example, a heat-resistant resin such as polyimide, polybenzimidazole, and polyamideimide can be given. Further, a solvent-soluble resin such as polyurethane, vinyl chloride, vinyl acetate, or polyvinyl alcohol, which can be easily formed into a film, or a curable resin such as epoxy, acrylic, styrene, phenol, or silicone may be used. These resins can be used as a mixture. Furthermore, inorganic fillers such as glass beads and calcium carbonate particles can be mixed with these liquid resins.

When the formation of the top coat layer 8 is completed, the base film 2 is then removed as shown in FIG. 3 (i) (step 9). Next, the first metal layer 3, a part of the second metal layer 5, and a part of the third metal layer 7 exposed by removing the base film 2 are scraped off by a known method such as etching or mechanical polishing (Step 10). As shown in FIG. 2 (j), only the second metal layer 5 and the third metal layer 7 covering the periphery of the waveguide 6 are left, and a protective coat layer 9 as a protective insulating material layer is further formed thereon. (Step 1
1). As the resin for the protective coat layer, it is possible to select the same resin as the resin for the top coat layer,
Taking into account the material's affinity and the warpage of the substrate due to the difference in the linear expansion coefficient during heating, it is preferable that the materials be the same.

By the above operation, as shown in FIG. 3, the waveguide 6 whose periphery is covered with the metal layer 5 for reflection and the metal layer 7 is formed.
Is formed in the top coat layer 8 and the protective coat layer 9 which are insulating resins.

As described above, the optical waveguide circuit 1 according to the present embodiment
In this case, since the entire periphery of the waveguide 6 is covered with the metal layers 5 and 7, light traveling outward from the side surface of the waveguide 6 is reflected by the metal layers 5 and 7 and returns into the waveguide 6. Similarly, when the light reaches the opposite side surface, the light is reflected by the metal layers 5 and 7 and returned into the waveguide 6. Eventually, the optical signal travels while being reflected in the waveguide 6, so that the optical signal travels in the waveguide 6 with almost no attenuation similarly to the optical fiber.

As described above, in the optical waveguide circuit 1 according to the present embodiment, since the periphery of the waveguide 6 is covered with the metal layers 5 and 7 for reflection, the top coat layer 8 made of an insulating material is used. , And in the protective coating layer 9 as it is, and the thickness of the entire optical waveguide circuit 1 can be reduced. Further, since the reflection metal layers 5 and 7 can be used as a part of a wiring pattern for an electric signal, the degree of integration can be further improved.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described. FIG. 4 is a flowchart of a method of manufacturing the optical waveguide circuit according to the present embodiment, FIG. 5 is a vertical sectional view of the optical waveguide circuit according to the present embodiment during manufacture, and FIG. 6 is an optical waveguide circuit according to the present embodiment. It is a perspective view of a circuit.

To manufacture the optical waveguide circuit 1 according to the present embodiment, first, a base film 12 as shown in FIG. 5A is prepared (step 1). This base film 1
Examples of the resin 2 include resins having heat insulation and electric insulation, such as epoxy resin, phenol resin, and polyimide.

Next, a metal layer 13 as a first metal layer is formed on one surface of the base film 12 by plating, sputtering or another known method (step 2). Next, a masking layer 14 is formed on the first metal layer 13. As the masking layer 14, for example, a photosensitive resin can be used. In this case, masking is performed in accordance with a predetermined waveguide pattern, exposure is performed from above, the waveguide pattern is transferred to a photosensitive resin layer, and developed to remove unnecessary portions, as shown in FIG. 5C. A groove 14a corresponding to such a waveguide pattern is formed (step 3). Next, a groove 16a formed corresponding to the waveguide pattern is filled with a light transmitting material 15 to form a waveguide 16 (step 4).

After the formation of the waveguide 16, the masking layer 14 is removed and the side surface of the waveguide 16 is removed as shown in FIG.
Then, the surface of the first metal layer 13 is exposed (Step 5). Next, as shown in FIG. 5 (f), the exposed side surface of the waveguide 16 and the surface of the first metal layer 13 are subjected to plating, sputtering or other known methods, as shown in FIG.
A second metal layer 17 is formed (Step 6). Then FIG.
As shown in (g), a top coat layer 18 as an insulating material layer is formed on the second metal layer 17 (Step 7). As a material for the top coat layer 18 used here, for example, a resin having a heat insulating property and an electric insulating property, such as an epoxy resin, a phenol resin, and a polyimide, may be mentioned.

By the above operation, as shown in FIG. 6, the waveguide 16 whose periphery is covered with the reflective metal layer 13 and the metal layer 17 forms the base film 12 made of an insulating resin layer and the top coat layer 18. The optical waveguide circuit 11 interposed therebetween is formed.

As described above, in the optical waveguide circuit 11 according to the present embodiment, since the periphery of the waveguide 16 is covered with the metal layers 13 and 17 for reflection, the top coat layer 18 made of an insulating material, In addition, the optical waveguide circuit 11 can be provided as it is in the base film 12, and the thickness of the entire optical waveguide circuit 11 can be reduced. The reflection metal layers 13 and 17
Can be used as a part of a wiring pattern for an electric signal, so that the degree of integration can be further improved.

In the present embodiment, the waveguide 16 is formed by forming a groove 14a in a portion corresponding to the waveguide pattern of the masking layer 14, and filling the groove 14a with a light transmitting material 15. However, the masking layer 1
4, a light-transmitting material layer 16A (not shown) made of a photosensitive resin is formed on the entire surface of the first metal layer 13, and only a portion corresponding to the waveguide pattern in the light-transmitting material layer 16A is insolubilized. The waveguide 16 may be formed by insolubilizing and forming a portion of the waveguide 16 by using photolithography technology in which masking and exposure are performed. In this case, there is an advantage that the step of forming the masking layer 14 can be omitted, and the use of the material for forming the masking layer 14 can be omitted.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described. FIG. 7 is a flowchart of a method of manufacturing the optical waveguide circuit according to the present embodiment, FIG. 8 is a vertical cross-sectional view of the optical waveguide circuit according to the present embodiment during manufacture, and FIG. 9 is an optical waveguide circuit according to the present embodiment. It is a perspective view of a circuit.

In order to manufacture the optical waveguide circuit 21 according to the present embodiment, first, a base film 22 as shown in FIG. 8A is prepared (Step 1). Examples of the base film 22 include resins having heat insulation and electric insulation, such as epoxy resin, phenol resin, and polyimide.

Next, a metal layer 23 as a first metal layer is formed on one surface of the base film 22 by plating, sputtering or another known method (step 2). Next, a masking layer 24 is formed on the first metal layer 23. As the masking layer 24, for example, a photosensitive resin can be used. In this case, masking is performed according to a predetermined waveguide pattern, exposure is performed from above, the waveguide pattern is transferred to a photosensitive resin layer, and development is performed to remove unnecessary portions, as shown in FIG. A groove 24a corresponding to such a waveguide pattern is formed (step 3). Next, as shown in FIG. 8D, the light transmitting material 25 is formed in the groove 24a formed corresponding to the waveguide pattern.
To form a waveguide 26 (step 4).

After the formation of the waveguide 26, the masking layer 24 is removed, and as shown in FIG.
Then, the surface of the first metal layer 23 is exposed (Step 5). Next, as shown in FIG. 8F, a top coat layer 27 is formed from the exposed side surface of the waveguide 26 and the surface of the first metal layer 23 (step 6). The material for the top coat layer 27 used here has a lower refractive index than the light transmitting material 25 and functions as a cladding material for the waveguide 26, for example, acrylic (refractive index 1.49), fluorinated Acrylic, fluorinated polyimide, poly 4-methylpentene-1 (refractive index 1.46
6), a low refractive index material such as polyvinylidene chloride (refractive index: 1.4710) is preferred.

By the above operation, as shown in FIG. 9, the waveguide 26 whose bottom surface is covered with the reflective metal layer 24 is made of the base film 22 and the top coat layer 2 made of an insulating resin.
The optical waveguide circuit 21 disposed in the inside 7 is formed.

As described above, in the optical waveguide circuit 21 according to the present embodiment, the bottom surface of the waveguide 26 is covered with the metal layer 24 for reflection, and the periphery other than the bottom surface is an insulating material functioning as a clad material. Since the optical signal is covered with the resin top coat layer 27, the optical signal can be transmitted with almost no attenuation. Further, since the reflection metal layer 24 can be used as a part of a wiring pattern for an electric signal, the degree of integration can be further improved. Further, the method according to the present embodiment has a specific effect that the optical waveguide circuit 21 can be formed in a short process.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described. FIG. 10 is a flowchart of the method of manufacturing the optical waveguide circuit according to the present embodiment.
Is a vertical cross-sectional view of the optical waveguide circuit according to the present embodiment in the process of being manufactured, and FIG. 12 is a perspective view of the optical waveguide circuit according to the present embodiment.

To manufacture the optical waveguide circuit 1 according to this embodiment, first, a base film 32 as shown in FIG. 11A is prepared (step 1). Next, as shown in FIG. 11B, a metal layer 33 as a first metal layer is formed on one surface of the base film 32 by plating, sputtering or another known method (Step 2). Next, a masking layer 34 is formed on the first metal layer 33. As the masking layer 34, for example, a photosensitive resin can be used. In this case, masking is performed in accordance with a predetermined waveguide pattern, exposure is performed from above, the waveguide pattern is transferred to a photosensitive resin layer, and development is performed to remove unnecessary portions, as shown in FIG. A groove 34a corresponding to such a waveguide pattern is formed (step 3).

Next, as shown in FIG. 11D, a metal layer 35 as a second metal layer is formed on the bottom of the groove 34a formed corresponding to the waveguide pattern by plating, sputtering or other known method, as shown in FIG. Is formed (step 4). Next, as shown in FIG. 11E, a light transmitting material 36 is filled on the second metal layer 35 formed at the bottom of the groove 34a to form a waveguide 37 (step 5). As the light transmitting material 36 used here, a material having a lower refractive index than the light transmitting material 35 and functioning as a cladding material for the waveguide 37 is used.

After forming the waveguide 37, the masking layer 3
4 is removed (step 6), and the side surfaces of the first metal layer 33, the second metal layer 35, and the side surface of the waveguide 37 are exposed as shown in FIG. Then the first exposed like this
A top coat layer 38 is formed on the surface of the metal layer 33, the side surface of the second metal layer 35, and the side surface of the waveguide 37 (Step 7).

After the top coat layer 38 has been formed, the base film 32 is removed to expose the surface of the first metal layer 33 as shown in FIG. 11H (step 8). Next, the first metal layer 33 thus exposed is subjected to a process such as etching to remove the first metal layer 33 (Step 9),
A top coat layer 38 is provided on the surface of the second metal layer 35 and on both sides thereof.
Expose the surface. Next, a protective coat layer 39 as an insulating material layer is formed on the exposed surface of the second metal layer 35 and the surface of the top coat layer 38 on both sides thereof (step 10). By the above operation, as shown in FIG. 12, the waveguide 37 whose upper surface is covered with the reflective metal layer 35 is formed of the top coat layer 38 and the protective coat layer 3 made of an insulating resin.
The optical waveguide circuit 31 disposed in the substrate 9 is formed.

As described above, in the optical waveguide circuit 31 according to the present embodiment, the upper surface of the waveguide 37 is covered with the metal layer 35 for reflection, and the periphery other than the upper surface functions as an insulating material that functions as a clad material. Since the optical signal is covered with the resin top coat layer 38, the optical signal can be transmitted with almost no attenuation. Further, since the reflection metal layer 35 can be used as a part of a wiring pattern for an electric signal, the degree of integration can be further improved.

(Embodiment 1) An embodiment of the present invention will be described below. In this example, the optical waveguide formed a color according to the process of the second embodiment. At that time, polyimide was used as a base film. As the first metal layer, a rolled copper foil (10 μm thick) was used, but other than this, a metal having high reflectivity and high conductivity, such as silver or gold, or iron, chromium, nickel, aluminum, tin, lead, or any of them. It may be an alloy. As a film forming method, an electroless plating method or the like can be used in addition to a vacuum technique such as a vapor deposition method or a sputtering method. As the resist used for the masking layer, an ultraviolet-sensitive resist that is usually used in a process for manufacturing a printed wiring board was used. A transparent epoxy resin was used as a resin forming the waveguide.

When a waveguide is formed, a liquid low-molecular epoxy resin is applied by a spin coating method, and then the resin adhering to the surface is removed by a doctor blade to fill only the inside of the groove formed by the resist. Thereafter, heat was applied to cure the film, thereby forming a waveguide. The second metal layer is the first metal layer.
Like the metal layer, a copper layer was formed by an electroless plating method. As a method other than the above, a metal having high reflectivity and high conductivity such as silver or gold, iron, chromium, nickel, aluminum, tin, lead, or an alloy thereof may be used.

Although the electroless plating method is used as the film forming method, it is also possible to use a vacuum film forming technique such as an evaporation method or a sputtering method. The top coat layer is not essential, but can be provided as needed. In this example, the polyimide film was laminated using an epoxy adhesive.

In the thus-obtained optical waveguide circuit having the structure of the present embodiment, the optical wiring patterns on the same plane are disposed on a common first metal layer and have the same potential level. Become. In this case, the first metal layer can be used as a ground layer or a power supply layer in an electric circuit. The dimensions of the core material obtained as described above have a cross section of 20 μm × 20.
It was a square of μm and 10 cm in length. As a comparative example, when the signal transmission loss was measured when the conventional clad material was used, the conventional product was -2 dB, whereas the optical waveguide circuit of the present example obtained a good result of -0.2 dB. .

(Example 2) In this example, an optical waveguide circuit was manufactured according to the process described in the first embodiment.
In the present embodiment, the same materials as those of the first embodiment were used for each material including the third metal layer. In the present embodiment, since not all the periphery of the waveguide is covered with the metal reflection layer,
The top coat layer is required to have properties as a clad material having a lower refractive index than the core material. However, when electric circuits are mixed, the first metal layer can function as a shield layer (ground layer). The dimensions of the core material obtained in this way are square with a cross section of 20 μm × 20 μm,
The length was 10 cm. As a comparative example, when the signal transmission loss was measured in comparison with the case where the conventional clad material was used, the conventional product was -2 dB, whereas the optical waveguide circuit of the present embodiment obtained a good result of -1.5 dB. .

Example 3 In this example, an optical waveguide circuit was manufactured in accordance with the process described in the third embodiment.
In the present embodiment, the same materials as those of the first embodiment were used for each material including the third metal layer. In the present embodiment, since the metal layers constituting each waveguide are independent between the waveguides, different electric signals can flow.

The dimensions of the core material obtained in this way were a square having a cross section of 20 μm × 20 μm and a length of 10 c
m. As a comparative example, the signal transmission loss was measured in comparison with the case where the conventional clad material was used.
On the other hand, the optical waveguide circuit of this embodiment is -0.2 dB.
A good result was obtained.

(Example 4) In this example, an optical waveguide circuit was manufactured according to the process described in the fourth embodiment.
In the present embodiment, the same materials as those of the first embodiment were used for each material including the third metal layer. In the present embodiment, since the metal layers constituting each waveguide are independent between the waveguides, different electric signals can flow.
However, since the entire periphery of the waveguide is not covered with the metal reflective layer, the protective coat layer is required to have a characteristic as a clad material having a lower refractive index than the core material.

The dimensions of the core material obtained in this way were square with a cross section of 20 μm × 20 μm and a length of 10 c
m. As a comparative example, the signal transmission loss was measured in comparison with the case where the conventional clad material was used.
On the other hand, the optical waveguide circuit of the present embodiment is -1.5 dB.
A good result was obtained.

[0050]

According to the present invention, since the metal reflection layer is provided around the waveguide, the waveguide can be provided in the insulating layer of the electric wiring layer, and therefore, the optical waveguide can be provided. The thickness of the entire circuit can be reduced. Further, the integration degree can be further increased by connecting the metal reflection layer and the electric wiring pattern and using the reflection layer as a part of the electric wiring pattern.

[Brief description of the drawings]

FIG. 1 is a flowchart of a method for manufacturing an optical waveguide circuit according to a first embodiment.

FIG. 2 is a vertical cross-sectional view of the optical waveguide circuit according to the first embodiment during manufacture.

FIG. 3 is a perspective view of the optical waveguide circuit according to the first embodiment.

FIG. 4 is a flowchart of a method for manufacturing an optical waveguide circuit according to a second embodiment.

FIG. 5 is a vertical cross-sectional view of the optical waveguide circuit according to the second embodiment during manufacture.

FIG. 6 is a perspective view of an optical waveguide circuit according to a second embodiment.

FIG. 7 is a flowchart of a method for manufacturing an optical waveguide circuit according to a third embodiment.

FIG. 8 is a vertical sectional view of the optical waveguide circuit according to the third embodiment in the process of being manufactured.

FIG. 9 is a perspective view of an optical waveguide circuit according to a third embodiment.

FIG. 10 is a flowchart of a method for manufacturing an optical waveguide circuit according to a fourth embodiment.

FIG. 11 is a vertical sectional view of the optical waveguide circuit according to the fourth embodiment in the process of being manufactured.

FIG. 12 is a perspective view of an optical waveguide circuit according to a fourth embodiment.

FIG. 13 is a vertical sectional view of a conventional optical waveguide circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical waveguide circuit, 2 ... 1st metal layer, 4 ... Masking layer
5: second metal layer, 6: waveguide, 7: reflective layer (third metal layer), 8: insulating substrate, 9: protective coat layer (insulating substrate).

Claims (10)

[Claims] 1. A light guide comprising: an insulating substrate; a waveguide disposed in the insulating substrate, formed of a light transmitting material; and a reflective layer covering at least a part of an outer peripheral surface of the waveguide. Wave circuit. 2. The optical waveguide circuit according to claim 1, wherein a single layer or a plurality of layers of conductive wiring patterns connected to each other are provided on the surface and / or inside the insulating substrate. An optical waveguide circuit, comprising: 3. The optical waveguide circuit according to claim 2, wherein the reflection layer is made of a conductive material and forms a part of the conductive wiring pattern. 4. The optical waveguide circuit according to claim 1, wherein the light transmitting material is an organic material or a gas. 5. The optical waveguide circuit according to claim 1, wherein the insulating substrate is a flexible substrate. 6. A step of forming a first metal layer on a base film, a step of forming a masking layer on the first metal layer, and patterning the masking layer to form a groove-shaped conductor corresponding to a waveguide. Forming a waveguide pattern; forming a second metal layer at the bottom of the waveguide pattern; filling a light-transmitting material on the second metal layer to form a waveguide; and forming the masking layer. Removing; forming a third metal layer covering the first metal layer, the side surface of the second metal layer, and the surface of the waveguide; and an insulating material layer on the third metal layer Forming the base film; removing the base film; leaving the third metal layer and the second metal layer covering the outer periphery of the waveguide; the first metal layer; the second metal layer; A part of the third metal layer is removed, and an insulating material is removed. Exposing a layer; and forming a protective insulating material layer on the third metal layer and the second metal layer covering the outer periphery of the waveguide and the exposed insulating material layer. Wave circuit manufacturing method. 7. A step of forming a first metal layer on a base film, a step of forming a masking layer on the first metal layer, and patterning the masking layer to form a groove-shaped conductor corresponding to a waveguide. Forming a waveguide pattern; filling the waveguide pattern with a light-transmitting material to form a waveguide; removing the masking layer; and forming the first metal layer and the waveguide. Forming a second metal layer covering the surface, forming an insulating material layer on the second metal layer, forming a protective insulating material layer on the second metal layer; A method for manufacturing an optical waveguide circuit comprising: 8. A step of forming a first metal layer on a base film, a step of forming a photosensitive material layer on the first metal layer, and a portion of the photosensitive material layer corresponding to a waveguide or a non-waveguide. Exposing a substantial portion to form a waveguide pattern; developing the exposed photosensitive material layer to form a waveguide; covering the first metal layer and the surface of the waveguide Forming a second metal layer, forming an insulating material layer on the second metal layer, and forming a protective insulating material layer on the second metal layer. Manufacturing method of optical waveguide circuit. 9. A step of forming a first metal layer on a base film, a step of forming a masking layer on the first metal layer, and patterning the masking layer to form a groove-shaped conductor corresponding to a waveguide. Forming a waveguide pattern; filling the waveguide pattern with a light-transmitting material to form a waveguide; removing the masking layer; and forming the first metal layer and the waveguide. Forming an insulating material layer for protection on the surface. 10. A step of forming a first metal layer on a base film, a step of forming a masking layer on the first metal layer, and a step of patterning the masking layer to form a groove-shaped conductor corresponding to a waveguide. Forming a waveguide pattern; forming a second metal layer at the bottom of the waveguide pattern; filling a light-transmitting material on the second metal layer to form a waveguide; and forming the masking layer. Removing the base film; forming an insulating material layer covering the side surfaces of the first metal layer, the second metal layer, and the surface of the waveguide; removing the base film; Removing the first metal layer while leaving the second metal layer covering the bottom of the waveguide, exposing an insulating material layer and the second metal layer; and the second metal layer covering the bottom of the waveguide. On the exposed insulating material layer Forming an insulating material layer for protection in the optical waveguide circuit.