JP2008281939A - Method of manufacturing optical substrate and optical substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical substrate for stably and continuously obtaining a circular core pattern cross-section and is suitable for mass production in the manufacture of optical waveguide using a polymer material. <P>SOLUTION: The method includes: forming a groove of a desired pattern on the upper surface of a first resin base material having light transmission property; dropping adhesive into the grooves, laying a metal line of a desired diameter into the groove to fix the metal line and covering the first resin base material and the metal line with a second resin base material having light transmission property to form an integrated stack; cutting the stack to desired size; immersing the cut stack into etching liquid and dissolving the metal line to form holes; immersing the stack with the holes formed into a third resin base material having a refractive index different from those of the first and second resin base materials and light transmission property at the atmospheric pressure or below to fill the holes with the third resin base material; and curing the filled third resin base material to form cores of the optical waveguide. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an optical substrate manufacturing method used for an optical integrated circuit, an optical interconnector, an optical multiplexer / demultiplexer, or the like used for optical communication and optical information processing.

With the progress of advanced information technology in recent years, the performance of information processing apparatuses such as routers and servers used for information communication has been improved, and further speeding up of communication signals is required in these devices. In this speeding up, the communication quality of the electrical wiring in the electronic circuit or the electric circuit becomes an obstacle to improving the performance, so that this obstacle cannot be ignored in increasing the communication speed.

Therefore, as a promising technique for solving problems that hinder high-speed communication, such as increasing the processing signal speed and reducing electrical noise, a technique using optical wiring is attracting attention. In particular, in order to realize large-capacity optical interconnection using optical wiring, high density optical wiring and low loss connection are important, and various technical studies for high performance and cost reduction have been conducted. Yes. As a specific method for realizing this optical interconnection, a method using an optical waveguide has been studied. In this optical waveguide, a first cladding layer made of a light-transmitting material is formed, and a core layer pattern made of a light-transmitting material having a refractive index smaller than that of the first cladding layer is formed thereon. Further, an optical waveguide can be obtained by covering the core layer pattern with a light-transmitting material layer having a refractive index larger than that of the core layer pattern as the second cladding layer.

Various studies have been made on these optical waveguides, and various studies have attracted attention that polymer materials are advantageous in terms of cost and processability, and active development is underway. As an example of a method for forming this optical waveguide, there is a method of forming a desired core pattern of an optical waveguide by applying a photopolymer material having optical transparency and repeating photolithography, or a desired core pattern of an optical waveguide. There is a method in which the formed molding die is pressure-molded and heat-cured. However, since the cross-sectional shape of the core pattern of the optical waveguide formed by these methods is a quadrangle (square), there is a drawback that the optical transmission loss and scattering at the connection boundary surface tend to increase at the end face of the core pattern. .

Focusing on this point, various manufacturing methods for making the cross-sectional shape of the core pattern of the optical waveguide circular have been studied. For example, as shown in Patent Document 1, a surfactant is printed in a stripe shape, a high refractive index transparent liquid material is applied and formed in a gap portion of the stripe, and the core pattern cross section is formed by curing it. There is a manufacturing method for forming a nearly circular optical waveguide. However, since this method forms a circular cross section by utilizing the water / oil repellency of the surfactant, stable productivity depends solely on the efficacy of the surfactant. However, the effectiveness of the surfactant decreases with the frequency of contact with the high refractive index transparent material, that is, with the increase in the production quantity of the optical waveguide. According to this method, a circular cross section can be obtained stably and repeatedly. Is difficult.

In addition, as shown in Patent Document 2, a reactive oil liquid prepolymer is selectively applied onto a substrate having an oil-repellent region and an oleophilic region formed in the core pattern of the optical waveguide. There is a manufacturing method in which an optical waveguide having a circular cross section is formed in a self-aligning manner by the surface tension of the liquid prepolymer, and then the reactive oil liquid prepolymer is cured to obtain a smooth circular cross section. However, this method has the disadvantage that the cross-sectional shape tends to be deformed and the light propagation characteristics are likely to be deteriorated because contact with the reactive oil liquid prepolymer occurs at the interface between the oil repellent region and the lipophilic region. In addition, since the diameter of the core layer expands depending on the amount of the material to be supplied, it is necessary to perform strict control so that the required amount of the high-viscosity core material is supplied in the manufacturing process, and advanced control technology is required. Become.

Furthermore, as shown in Patent Document 3, after forming a photosensitive resin layer on at least one side of the printed wiring board, a concave groove is formed so as to reach the base material below the photosensitive resin layer, A manufacturing method for forming an optical fiber by installing an optical fiber in a concave groove and covering it with a resin has also been studied (hereinafter, laying an optical fiber, a metal wire, or the like may be referred to as a laying line). ). However, since this method uses the optical fiber itself as the optical wiring, the wiring pattern to be laid is designed in a rectangular shape, and particularly when the optical fiber does not have sufficient bending resistance, the optical fiber is It breaks and cannot be routed according to the design pattern. Therefore, there is a problem that it is difficult to cope with various wiring patterns.

Japanese Patent Laid-Open No. 3-15805 JP 2002-202426 A JP 2003-14946 A

The present invention has been made in view of the above problems, and is suitable for mass production in which a circular core pattern cross section can be obtained stably and continuously in the manufacture of an optical waveguide using a polymer material. An object of the present invention is to provide a method for manufacturing an optical substrate.

In the invention according to claim 1 of the present invention, a groove having a desired pattern is formed on the upper surface of the first resin substrate having light transmittance, an adhesive is dropped on the groove, and a groove having a desired diameter is formed. A metal wire is laid and fixed, and the first resin base material and the metal wire are covered with a second resin base material having optical transparency to form an integrated laminate, and the laminate is desired. The cut laminate is dipped in an etching solution to dissolve the metal wire to form pores, and the laminate having the pores is formed at the first and The third resin base material filled with the third resin base material by immersing in a third resin base material having light transmittance with a refractive index different from that of the second resin base material. An optical substrate manufacturing method characterized by forming a core of an optical waveguide by curing the core.

The invention according to claim 2 of the present invention is the method for manufacturing an optical substrate according to claim 1, wherein the adhesive is an adhesive mainly composed of a material of the second resin base material. It is what.

The invention according to claim 3 of the present invention is the method for manufacturing an optical substrate according to claim 1, wherein the desired pattern is a core pattern of an optical waveguide.

The invention according to claim 4 of the present invention is the method for producing an optical substrate according to claim 1, wherein the diameter of the metal wire is the same as the diameter of the core to be formed.

The invention according to claim 5 of the present invention is the method of manufacturing an optical substrate according to claim 1, wherein the core has a substantially circular cross section.

The invention according to claim 6 of the present invention is the optical substrate manufacturing method according to claim 1, wherein the first to third resin base materials are ultraviolet curable resin base materials. It is.

In the invention according to claim 7 of the present invention, the first resin base material is formed on a support by any one of a spin coating method, a dip coating method, a roll coating method, and a die coating method. 2. The resin substrate according to claim 1, wherein the resin substrate is formed on the first resin substrate and the metal wire by any one of a spin coating method, a roll coating method, and a die coating method. This is a method for manufacturing an optical substrate.

The invention according to claim 8 of the present invention is characterized in that the first and second resin substrates are substrates formed by applying a resin to a film-like substrate and bonding them together. Item 14. A method for manufacturing an optical substrate according to Item 1.

The invention according to claim 9 of the present invention is an optical substrate manufactured by the method for manufacturing an optical substrate according to any one of claims 1 to 8.

According to a tenth aspect of the present invention, there is provided an optical integrated circuit comprising at least the optical substrate according to the ninth aspect.

According to an eleventh aspect of the present invention, there is provided an optical interconnector comprising at least the optical substrate according to the ninth aspect.

According to a twelfth aspect of the present invention, there is provided an optical multiplexer / demultiplexer including at least the optical substrate according to the ninth aspect.

  ADVANTAGE OF THE INVENTION According to this invention, in the manufacture of the optical waveguide using a polymeric material, the manufacturing method of the optical substrate suitable for mass production which can obtain a circular core pattern cross section stably and continuously can be provided.

The manufacturing method of the optical substrate of the present invention will be described. First, a support for forming an optical substrate is prepared. As the support, a silicon wafer, a metal plate such as iron, copper, or stainless steel, a glass substrate having a smooth surface, a resin film material having a smooth surface, or the like can be used. In particular, a silicon wafer, a ferritic stainless steel, or a martensitic stainless steel having a small dimensional variation in terms of linear expansion coefficient is preferably used from the viewpoint of accuracy. Examples of the ferritic stainless steel include SUS405, SUS429, SUS430, SUS430F, and SUS434. Examples of the martensitic stainless steel include SUSU403, SUS410, and SUS630.

Next, a first cladding layer (hereinafter sometimes referred to as a first resin base material) is formed on the support. As a method for forming the first cladding layer, the formation method differs depending on whether a liquid material is used or a solid material such as a film-like substrate is used. When the material of the first cladding layer is a liquid, spin coating, dip coating, roll coating, die coating, and the like are suitable. The spin coating method is a method in which a liquid material is dropped on a support and the support is rotated at a constant rotation number to form a coating film having a constant film thickness on the support. The dip coating method is a method in which a support is immersed in a first cladding layer material and pulled up at a constant speed to form a coating film on the support. The roll coating method is a method in which a first clad material having a constant film thickness is formed on an application roll, and then the application roll is brought into contact with a support to transfer and apply the material on the roll to the support. The method is a method in which a coating material is formed on a support by projecting a coating material from a metal head (die) that maintains a constant distance between the support and the coating film thickness. In the case of using a solid material formed by previously applying a liquid material to a film-like base material as the first cladding material, the first base material can be obtained by laminating (bonding) the film base material onto the support. It is possible to form a cladding layer. After the first cladding layer material is formed on the support, the coating film is cured as necessary. As a curing method, curing by heat, curing by ultraviolet rays, or the like can be applied, and the means can be selected depending on the curing form of the material. As a material for the first cladding layer, a commonly used polymer material can be used. The same applies to the core layer and the second cladding layer.

Next, a guide groove corresponding to a desired wiring pattern (core pattern) of the optical waveguide is formed on the upper surface of the first cladding layer. This guide groove serves as a reference for a wiring pattern to be formed later based on this guide groove. For the formation of the guide groove, router processing that can form an arbitrary pattern shape by rotating a fine drill blade, laser processing that performs pattern processing by irradiating the first cladding layer with light from a laser light source Can be suitably used. As the laser processing method, for example, carbon dioxide laser processing, UV-YAG laser processing, excimer laser processing, femtosecond laser processing, and the like can be applied.

Next, a metal wire is laid along the guide groove formed on the upper surface of the first cladding layer, and placed on the first cladding layer as a wiring pattern. This wiring pattern is the core pattern of the optical waveguide that is finally formed. Therefore, a metal wire with no coating is used as the metal wire, and a metal wire having the same diameter as that of the core layer to be finally formed as an optical waveguide is used. In addition, when laying a line, it is possible to lay out an accurate wiring pattern by adhering and fixing the metal line to the guide groove not only at the start point and end point of the metal line but also at the change point of the wiring shape. As an adhesive for bonding the metal wire, an adhesive made of the same material as the second cladding layer material is used. This is because such an adhesive is preferable for optical transmission because it has the same optical characteristics as the second clad layer that covers the metal wire in a later step. The metal wire is fixed by curing the adhesive, and there are curing by heat, curing by ultraviolet rays, and the like, and the means can be selected depending on the curing form of the adhesive material. As an example, when an ultraviolet curable photosensitive material is applied as the adhesive material (that is, the second cladding layer material), the curing is performed in a shorter time compared to the thermosetting material. An optical substrate can be formed, which is preferable. In addition, although the metal wire without a coating was used as a metal wire, it is not necessarily limited to this, and using a metal wire coated with a material having the same optical characteristics as the second cladding layer and the adhesive. Also good.

Next, a second cladding layer (hereinafter sometimes referred to as a second resin base material) is formed on the metal wire and the first cladding layer fixed along the guide groove. As a method for forming the second cladding layer, similarly to the formation of the first cladding layer described above, when the material of the second cladding layer is a liquid, a spin coating method, a roll coating method, a die coating method, or the like is used. be able to. However, the dip coating method cannot be applied. Further, when the second clad material is already applied and formed on the film-like substrate, the second clad layer can be formed by laminating (bonding) on the first clad layer and the metal wire. is there. Next, the second clad layer is hardened so that the metal wire fixed in the guide groove is covered with the second clad layer and fixed. Curing of the second cladding layer includes curing by heat and curing by ultraviolet rays, and the means can be selected depending on the curing mode of the second cladding layer material. As an example, when an ultraviolet curable photosensitive material is applied as the second cladding layer material, curing can be performed in a short time compared to a thermosetting material, so that an optical substrate can be efficiently formed. It is. The second cladding layer material is a material having a higher refractive index than the core material used later. By providing the difference in refractive index, it becomes possible to propagate an optical signal between a core layer and a clad layer to be formed later, which is preferable in forming an optical substrate. By curing and fixing the second cladding layer, a laminate composed of the first cladding layer, the metal wire, and the second cladding layer is formed on the support. Hereinafter, a material in which the first cladding layer, the metal wire, and the second cladding layer are stacked and fixed is referred to as a stacked body for the sake of explanation.

After forming the second cladding layer, the laminate formed on the support is cut with a dicing saw or the like into the desired size in the direction perpendicular to the stacking direction. From the cross section of the cut laminate, the cross section of the metal wire sandwiched between the first cladding layer and the second cladding layer is exposed. Next, a support body and a laminated body are peeled. Furthermore, the cross section where the metal wire of the laminated body which peeled is exposed is immersed in etching liquid, a metal wire is removed by an etching process, and a void | hole is formed in a laminated body. Etching of a metal wire can be performed by appropriately selecting and applying a chemical solution that dissolves the metal material as an etchant. For example, when the metal wire is a copper wire, a ferric chloride solution or a ferrous chloride solution can be used. It is preferable to perform the etching process with a copper solution. Further, the etching solution penetrates to the inside of the laminate by a capillary phenomenon, and the metal wire is reliably removed. In addition, since the void | hole formed here is formed holding the cross-sectional shape of a metal wire, if the shape of a metal wire is circular, it will become a circular hole, and if it is a rectangle, it will be a hole of a rectangular cross-sectional shape. However, in terms of optical transmission characteristics, the cross-sectional shape is preferably circular, and therefore a metal wire having a circular cross-sectional shape is preferably used.

Next, the formed cross-section of the laminate having pores is immersed in a liquid core material (hereinafter sometimes referred to as a third resin base material), and the core material is filled into the pores. The core material is filled into the holes by applying a capillary phenomenon. Therefore, it is preferable to immerse the cross section of the laminate in the core material under an atmospheric pressure environment lower than atmospheric pressure (that is, lower than atmospheric pressure). As a result, even when bubbles are mixed in the pores, for example, the bubbles are degassed and removed by being in a low pressure environment, and the filling of the core material is promoted. It is possible to obtain an optical substrate with few occurrences of defects. The low pressure environment is preferably 0.1 MPa or less. Next, the core material filled in the laminate is cured. The means for curing the core material can be selected depending on the curing form of the core material. Although there are curing by heat, curing by ultraviolet rays, etc., as in the case of the first cladding layer and the second cladding layer described above, if an ultraviolet curable photosensitive material is applied as the core material, it is compared with the thermosetting material. Since curing is performed in a short time, an optical substrate can be formed efficiently, which is preferable.

A desired optical substrate can be formed by cutting the laminate, which is finally cured and laminated, into a desired shape and size using a cutting means such as a dicing saw. In cutting, it is possible not only to form a cross section perpendicular to the stacking direction but also to form a mirror that refracts the light propagating through the core layer by cutting with a tilt angle with respect to the stacking direction. . The cutting direction can be suitably selected according to the use application of the optical substrate.

As described above, the manufacturing method of the present invention uses the metal wire having the same diameter as the optical waveguide to be formed, fills the hole formed by removing the metal wire by etching, and forms the core. . Therefore, a circular core pattern cross section can be obtained stably and continuously, and an optical substrate can be mass-produced efficiently. In addition, an optical substrate with a small optical transmission loss can be provided by the manufacturing method described above, and furthermore, by using such an optical substrate, an optical integrated circuit, an optical interconnector, and an optical multiplexer / demultiplexer with a small optical transmission loss. Can be provided.

Example 1
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the same code | symbol is attached | subjected about the same member. FIGS. 1A to 1E are cross-sectional views showing the formation of a first cladding layer, guide grooves, metal wires, and second grad layers of an optical substrate according to Example 1 of the present invention. 2A to 2D are cross-sectional views showing first grad layer peeling, metal line etching, core layer formation, and the like in Example 1 of the present invention.

A method for manufacturing an optical substrate according to Embodiment 1 of the present invention will be described. In order to form an optical substrate made of a polymer resin having a core layer 8 with a diameter of 50 μm, a stainless steel plate made of SUS430 material having a thickness of 0.5 mm was prepared as the support 1 (see FIG. 1A). On the support 1, a photosensitive epoxy resin having a refractive index of 1.53 was applied as a material of the first cladding layer 2 to a thickness of 500 μm by a die coating method. Next, the first clad layer 2 formed on the support 1 is irradiated with parallel ultraviolet light at an exposure dose of 500 mJ / cm ² using a parallel light ultraviolet irradiation device, and the first cladding is formed on the support 1. Layer 2 was formed in close contact (see FIG. 1B).

Next, a guide groove 3 corresponding to a wiring pattern having various shapes such as a straight portion and a curved portion was formed at a depth of 30 μm by router processing of a fine drill blade having a diameter of 100 μm (see FIG. 1C). ).

Next, an uncoated metal wire 4 made of a copper material having a diameter of 50 μm was laid along the formed guide groove 3. At this time, a photosensitive epoxy resin having a refractive index of 1.53, which is the same material as the second cladding layer, was used as the adhesive 5. The metal wire 4 was laid in line with the straight portion, the curved portion, etc. of the guide groove 3, and the adhesive 5 was dropped not only at the start point and the end point but also at the change point of the wiring shape. Next, using a parallel light ultraviolet irradiation device, the parallel light ultraviolet light was irradiated at an exposure amount of 500 mJ / cm ² , the adhesive 5 was cured, and the metal wire 4 was bonded and fixed (see FIG. 1D). By laying along the guide groove 3 in this way, the metal wire 4 was not bent at the change point of the wiring pattern, and could be laid according to the wiring pattern.

Next, a photosensitive material having a refractive index of 1.53 which is the same material as the material of the first cladding layer 2 is used as the material of the second cladding layer on the first cladding layer 2 on which the metal wire 4 made of copper is laid. The conductive epoxy resin was uniformly applied by a die coating method. Next, the surface of the applied photosensitive epoxy resin was scraped off using a fluororesin doctor blade in the absence of air bubbles. At this time, the surface of the photosensitive epoxy resin was scraped off at an interval of 20 μm from the outermost surface of the metal wire 4. Subsequently, using a parallel light ultraviolet irradiation device, the epoxy material was cured by irradiating ultraviolet rays at an exposure amount of 500 mJ / cm ² , and the metal wire 4 was covered and fixed with the first cladding layer 2 and the second cladding layer. The first clad layer 2 and the second clad layer are integrated by curing, and a laminated body (laminated body of the first clad layer 2, the metal line 4, and the second clad layer) 6 in which the metal wire 4 is embedded is formed ( (See FIG. 1 (E)).

The laminated body 6 in which the support 1 and the metal wire 4 were embedded was cut into a rectangle having a width of 3 mm and a length of 120 mm using a dicing saw. The cross section of the metal wire 4 having a diameter of 50 μm was exposed on the cut surface of the laminate 6. Next, in a state where the laminate 6 and the support 1 are in close contact with each other, an adhesive tape is brought into contact with the edge of the surface of the laminate 6 so that the laminate 6 in which the metal wire 4 is embedded is physically removed from the support 1. It peeled. At this time, the laminated body 6 has the first clad layer 2, the metal wire 4, and the second clad layer firmly and firmly adhered, so that in the peeling, the first clad layer 2, the metal wire 4, The two clad layers were peeled together from the support 1 without being separated, and the material could be peeled off without remaining on the support 1 (see FIG. 2A).

Next, in order to remove the metal wire 4 by immersing the cross section of the laminated body 6 exfoliated from the support 1 and exposing the metal wire 4 in a cuprous chloride solution having a liquid temperature of 50 ° C. and a specific gravity of 1.55. Etching was performed to remove the metal wire 4 and form a hole 7 having a diameter of 50 μm in the laminate 6 (see FIG. 2B). The cross-sectional shape of the hole 7 is the same as the cross-sectional shape of the metal wire 4.

Next, the cross section of the laminate 6 in which the holes 7 were formed was immersed in a liquid photosensitive epoxy resin having a refractive index of 1.48, which is a material of the core layer 8, in a container having a pressure of 400 mmHg. It was confirmed that the core material was filled in the pores 7 by capillarity and was filled without bubbles. In this state, using a parallel light ultraviolet irradiation device, the core material was cured by irradiating parallel light with an exposure amount of 300 mJ / cm ² to form the core layer 8 (see FIG. 2C).

Finally, the laminate 6 formed by being cured and embedded so that the core layer 8 is embedded is cut with a dicing saw so as to have a length of 100 mm, so that a pattern with a core diameter of 50 μm is incident at a pitch of 250 μm. An optical substrate having a thickness of 150 μm formed so as to be emitted was formed, and its insertion loss was 3.5 dB (see FIG. 2D).

(Example 2)
Next, a method for manufacturing an optical substrate according to Embodiment 2 of the present invention will be described. FIGS. 3A to 3E are cross-sectional views showing the formation of the first cladding layer, the guide groove, the metal wire, and the second grad layer of the optical substrate according to Example 2 of the present invention. 4A to 4D are cross-sectional views showing the first grad layer peeling, metal wire etching, core layer formation, and the like in Example 2 of the present invention. Similarly to Example 1 described above, an alkali-free glass plate having a smooth surface with a thickness of 1.0 mm was prepared as the support 1 in order to form an optical substrate made of a polymer resin having a core layer 8 having a diameter of 50 μm. (See FIG. 3A). On the support 1, a photosensitive epoxy resin having a refractive index of 1.53 was applied as a material for the first cladding layer 2 to a thickness of 500 μm by a die coating method. Thereafter, the first clad layer 2 was formed in close contact with the support 1 by irradiating the parallel light ultraviolet light with an exposure dose of 500 mJ / cm ² using a parallel light ultraviolet irradiation device (see FIG. 3B).

Next, a guide groove 3 corresponding to a wiring pattern having various shapes such as a straight portion and a curved portion was formed at a depth of 30 μm by router processing of a fine drill blade having a diameter of 100 μm (see FIG. 3C). .

Next, an uncoated metal wire 4 made of an aluminum material having a diameter of 50 μm was laid along the formed guide groove 3. At this time, a photosensitive epoxy resin having a refractive index of 1.53, which is the same material as the second cladding layer, was used as the adhesive 5. This metal wire 4 was laid in line with the straight portion, the curved portion, and the like of the guide groove 3, and the adhesive 5 was dropped not only at the start point and the end point but also at the change point of the wiring shape. Then, the adhesive 5 was fixed by irradiating parallel light ultraviolet rays with an exposure amount of 500 mJ / cm ² using a parallel light ultraviolet irradiation device. As a result, the metal wire 4 was laid without bending even at the pattern change point (see FIG. 3D).

Next, on the first clad layer 2 on the support 1 on which the metal wire 4 made of this aluminum material is laid, the refractive index 1 is the same material as the first clad layer 2 as the material of the second clad layer. .53 photosensitive epoxy resin was uniformly applied by a die coating method. Next, the photosensitive epoxy resin was scraped off using a fluororesin doctor blade with a gap of 20 μm from the outermost surface of the metal wire 4 with no air bubbles mixed. Next, using a parallel light ultraviolet irradiation device, ultraviolet rays were irradiated at an exposure amount of 500 mJ / cm ² to cure the epoxy material, and the metal wire 4 was covered and fixed with the first cladding layer 2 and the second cladding layer. The first clad layer 2 and the second clad layer were integrated by curing, and a laminate 6 in which the metal wire 4 was embedded was formed (see FIG. 3E).

The laminate 6 in which the support 1 and the metal wire 4 were embedded was cut into a width of 3 mm and a length of 120 mm with a dicing saw. A cross section of the metal wire 4 having a diameter of 50 μm was exposed at the cut surface. Next, in a state of being in close contact with the support 1, an adhesive tape was brought into contact with the edge of the surface of the laminate 6 to physically peel the laminate 6 from the support 1. In the laminated body 6, the first clad layer 2, the metal wire 4, and the second clad layer are firmly cured and adhered, so that in the peeling, the first clad layer 2, the metal wire 4, and the second clad layer Were separated from the support 1 without being separated, and the material was able to be peeled off without adhering to the support 1 (see FIG. 4A).

Next, an etching process for removing the metal wire 4 is performed by immersing the cross section of the laminate 6 from which the metal wire 4 is peeled off from the support 1 in a 10 ° C., 10 wt% aqueous sodium hydroxide solution at a liquid temperature of 40 ° C. Then, the metal wire 4 was removed, and a hole 7 having a diameter of 50 μm was formed in the laminated body 6 (see FIG. 4B). The cross-sectional shape of the hole 7 is the same as the cross-sectional shape of the metal wire 4.

Next, the cross section of the laminate 6 in which the holes 7 were formed was immersed in a liquid photosensitive epoxy resin having a refractive index of 1.48, which is a material of the core layer 8, in a container having a pressure of 400 mmHg. It was confirmed that the core material was filled in the pores 7 by capillarity and was filled without bubbles. In this state, using a parallel light ultraviolet irradiation device, the core material was cured by irradiating parallel light with an exposure amount of 300 mJ / cm ² to form the core layer 8 (see FIG. 4C).

Finally, the laminate 6 formed by being cured and embedded so that the core layer 8 is embedded is cut with a dicing saw so as to have a length of 100 mm, so that a pattern with a core diameter of 50 μm is incident at a pitch of 250 μm. An optical substrate having a thickness of 150 μm formed so as to be emitted is formed, and its insertion loss is 3.5 dB. It was confirmed that the characteristics were the same as those of the first embodiment (FIG. 4D )reference).

According to the manufacturing method according to an embodiment of the present invention, an optical substrate can be efficiently mass-produced, and is inexpensive for an optical integrated circuit, an optical interconnector, or an optical multiplexer / demultiplexer used for optical communication and optical information processing. You can expect to use it.

It is sectional drawing in the formation process of the optical board | substrate which concerns on Example 1 of this invention. It is sectional drawing in the formation process of the optical board | substrate which concerns on Example 1 of this invention. It is sectional drawing in the formation process of the optical board | substrate which concerns on Example 2 of this invention. It is sectional drawing etc. in the formation process of the optical board | substrate which concerns on Example 2 of this invention.

Explanation of symbols

1: Support 2: First cladding layer 3: Guide groove 4: Metal wire
5: Adhesive 6: Laminate 7: Hole 8: Core layer

Claims (12)

Forming grooves of a desired pattern on the upper surface of the first resin base material having light transmittance;
Dropping an adhesive into the groove,
Laying and fixing a metal wire of a desired diameter in the groove,
Forming a laminated body in which the first resin base material and the metal wire are covered and integrated with a second resin base material having optical transparency;
Cutting the laminate to a desired size,
The cut laminate is immersed in an etching solution to dissolve the metal wire to form a hole,
The laminated body in which the pores are formed is immersed in a third resin base material having a light-transmitting property different from that of the first and second resin base materials at atmospheric pressure or less, so that the pores are formed in the first and second resin base materials. 3 filled with resin base material,
A method for producing an optical substrate, comprising: curing the filled third resin base material to form a core of an optical waveguide. The method for manufacturing an optical substrate according to claim 1, wherein the adhesive is an adhesive mainly composed of a material of the second resin base material. The method for manufacturing an optical substrate according to claim 1, wherein the desired pattern is a core pattern of an optical waveguide. The method of manufacturing an optical substrate according to claim 1, wherein the diameter of the metal wire is the same as the diameter of the core to be formed. The method of manufacturing an optical substrate according to claim 1, wherein a cross section of the core is substantially circular. The method of manufacturing an optical substrate according to claim 1, wherein the first to third resin base materials are ultraviolet curable resin base materials. The first resin substrate is formed on the support by any one of spin coating, dip coating, roll coating, and die coating methods,
The second resin base material is formed on the first resin base material and the metal wire by any one of a spin coat method, a roll coat method, and a die coat method. The manufacturing method of the optical board | substrate of description. 2. The method of manufacturing an optical substrate according to claim 1, wherein the first and second resin base materials are base materials formed by applying and bonding a resin to a film-like base material, respectively. An optical substrate manufactured by the method for manufacturing an optical substrate according to any one of claims 1 to 8. An optical integrated circuit comprising at least the optical substrate according to claim 9. An optical interconnector comprising at least the optical substrate according to claim 9. An optical multiplexer / demultiplexer comprising at least the optical substrate according to claim 9.

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