JP5810532B2 - Optical waveguide substrate and manufacturing method thereof - Google Patents

Description

  The present invention relates to an optical waveguide substrate and a method for manufacturing the same.

With the increase in information capacity, development of optical interconnection technology that uses optical signals not only for communication fields such as trunk lines and access systems but also for information processing in routers and servers is underway. Specifically, because light is used for short-distance signal transmission between boards in a router or server device, or as an optical transmission path, the degree of freedom of wiring is higher and the density is higher than optical fibers. An optical waveguide that can be used is used.
In addition, when the optical waveguide is used as a device of an optical product, it may be used in connection with another optical element such as an optical fiber (for example, Patent Document 1).
The optical products are connected by a plurality of optical fibers. For this reason, it is required that a tolerance for alignment when securing a plurality of optical waveguides formed on the substrate and a plurality of optical elements such as optical fibers can be secured.

JP 2001-42149 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical waveguide substrate and a method for manufacturing the same, which can ensure alignment tolerance when connecting a plurality of optical waveguides and a plurality of optical elements such as optical fibers.

The optical waveguide substrate according to the present invention is an optical waveguide substrate to which a plurality of cable-shaped optical elements are connected. The optical waveguide substrate includes a plate-shaped substrate and a plurality of optical waveguides formed above the upper surface of the substrate, each of which is optically connected to the end of each optical element. And a plurality of wall portions forming a plurality of pairs of side surfaces and a lower guide layer having a plurality of bottom surfaces, and a guide portion formed above the upper surface of the substrate. The plurality of wall portions and the lower guide layer each have a plurality of guide groove portions for guiding the end portions of the respective optical elements so that the positions of the end portions of the respective optical elements are aligned with the positions of the end portions of the respective optical waveguides. A plurality of guide groove portions each formed by each pair of side surfaces and each bottom surface are formed. The pair of side surfaces are formed at positions facing each other with the optical elements interposed therebetween. The plurality of bottom surfaces are optically connected to the end portions of the optical waveguides so that the end portions of the optical elements are advanced in the insertion direction in which the optical devices are inserted into the guide groove portions along the pair of side surfaces and the bottom surfaces. A plurality of inclined surfaces formed between each pair of side surfaces.
It is preferable that the distance between the inclined surface and the upper surface of the substrate increases as the distance increases.
The guide portion has a cover member that covers the openings of the plurality of guide groove portions on the upper surfaces of the plurality of wall portions, and the lower side of the cover member faces each bottom surface with each optical element interposed therebetween. Each having a plurality of pressing surfaces formed between each pair of side surfaces, each of the pair of side surfaces, each bottom surface, and each pressing surface each having a plurality of insertions for inserting the end portions of each optical element. It is preferable to form a hole.
The optical waveguide substrate according to the present invention preferably further includes a plate-shaped step portion for forming the plurality of inclined surfaces between the lower guide layer and the upper surface of the substrate.

The method of manufacturing an optical waveguide substrate according to the present invention includes a first step of forming the step portion on the upper surface of the substrate, a step of the step portion such that the upper surface of the lower guide layer forms a bottom surface. A second step of forming the lower guide layer on the upper surface of the substrate and the upper surface of the step portion so that the upper surface of the lower guide layer forms an inclined surface, and a bottom surface on the upper surface of the lower guide layer. And a third step of forming the plurality of wall portions so that the plurality of paired side surfaces can be formed at intervals such that the plurality of side surfaces can be formed.
The method for manufacturing an optical waveguide substrate according to the present invention may further include a fourth step of forming the lid member on the upper surface of the lower guide layer so as to cover the openings of the plurality of guide groove portions.

  ADVANTAGE OF THE INVENTION According to this invention, the optical waveguide board | substrate which can ensure the tolerance of the alignment at the time of connecting a several optical waveguide and several optical elements like an optical fiber, respectively, and its manufacturing method can be provided.

It is the perspective view which abbreviate | omitted a part of optical waveguide board | substrate of this invention. It is sectional drawing of the optical waveguide board | substrate shown in FIG. FIG. 2 is a side view of the optical waveguide substrate shown in FIG. 1. It is sectional drawing explaining the manufacturing method of the optical waveguide board | substrate shown in FIG. FIG. 5 is a cross-sectional view illustrating a method for manufacturing the optical waveguide substrate subsequent to FIG. 4. It is sectional drawing explaining the manufacturing method of the optical waveguide board following FIG. FIG. 7 is a cross-sectional view illustrating a method for manufacturing the optical waveguide substrate following FIG. 6. FIG. 8 is a cross-sectional view illustrating a method for manufacturing the optical waveguide substrate following FIG. 7. FIG. 9 is a cross-sectional view illustrating the method for manufacturing the optical waveguide substrate following FIG. 8. (A) is sectional drawing of the side with an optical waveguide. (B) is sectional drawing by the side of the guide part of an optical element. FIG. 10 is a cross-sectional view illustrating the method for manufacturing the optical waveguide substrate following FIG. 9. (A) is sectional drawing of the side with an optical waveguide. (B) is sectional drawing by the side of the guide part of an optical element. It is sectional drawing explaining the manufacturing method of the optical waveguide board | substrate following FIG. (A) is sectional drawing of the side with an optical waveguide. (B) is sectional drawing by the side of the guide part of an optical element. It is sectional drawing explaining the manufacturing method of the optical waveguide board | substrate following FIG. It is sectional drawing explaining the manufacturing method of the optical waveguide board | substrate following FIG.

An optical waveguide substrate 10 according to the present invention will be described with reference to FIGS.
Referring to FIGS. 1 to 3, the optical waveguide substrate 10 is configured to be connected to an optical fiber 5 that is a plurality of cable-shaped optical elements.
As shown in FIG. 1, the optical waveguide substrate 10 includes a plate-shaped substrate 20, an optical waveguide group 30 that is a plurality of optical waveguides (core layers 32) formed so as not to move relative to the substrate 20, and a plurality of optical waveguide substrates 30. A guide portion 40 for guiding the core layer 32 and a plate-like step portion 60 formed on the upper surface 22 a of the substrate 20.

  As shown in FIG. 2, the substrate 20 includes, for example, a rectangular plate member 22 having a flat upper surface 22 a and a lower surface 22 b, and electrical wiring 25 formed on the lower surface 22 b of the substrate 20. There is no restriction | limiting in particular as a material of the board member 22, For example, a glass epoxy resin substrate, a ceramic substrate, a glass substrate, a silicon substrate, a plastic substrate, a metal substrate, a substrate with a resin layer, a substrate with a metal layer, a plastic film, a resin layer And a plastic film with a metal layer and a plastic film with a metal layer.

The optical waveguide group 30 including a plurality of optical waveguides (core layer 32) includes a substrate 20 such that the end portion 35 of each optical waveguide (core layer 32) and the end portion 6 of each optical fiber 5 are optically connected. Is formed on the second lower cladding layer 42 of the guide portion 40 formed above the upper surface 22a. There is a part of the space formed by the slit groove 36 between the end 35 of each optical waveguide (core layer 32) and the end 6 of each optical fiber 5. The size of a part of this space is not particularly limited as long as the optical connection between the end 35 of the optical waveguide (core layer 32) and the end 6 of each optical fiber 5 is possible.
The plurality of core layers 32 are stacked on the first lower cladding layer 31 stacked on the second lower cladding layer 42. The plurality of core layers 32 are surrounded by a first lower clad layer 31 and an upper clad layer 33 that covers the core layer 32.
In the present embodiment, the plurality of optical waveguides (core layer 32) are arranged such that the plurality of end portions 35 are located on the same plane, and the plurality of optical waveguides (core layer 32) extends on the upper surface 22a of the substrate 20. The second lower cladding layer 42 is formed so as to be aligned in the direction. Therefore, the end portions 35 of the plurality of optical waveguides (core layer 32) are arranged at equidistant positions from the upper surface 22a of the substrate 20. Further, two adjacent optical waveguides (core layer 32) among the plurality of optical waveguides (core layer 32) are optically connected to the end portion 6 of each optical fiber 5 at the end portion 35 of each optical waveguide (core layer 32). The second lower cladding layer 42 is formed at a predetermined interval so as to be connected to the second lower cladding layer 42.

  As shown in FIGS. 2 and 3, the guide portion 40 is formed above the upper surface 22 a of the substrate 20, and has a plurality of wall portions 44 that form a plurality of paired side surfaces 43 and a second bottom surface 41. The lower cladding layer 42, the upper guide portion 47, and the lid member 50 are included. Accordingly, the second lower cladding layer 42 functions as a lower guide layer.

The plurality of wall portions 44 are formed on the upper surface 42a of the second lower cladding layer 42 so as to be aligned in the direction in which the end portions 35 of the plurality of optical waveguides (core layers 32) are aligned. An interval between two adjacent wall portions 44 among the plurality of wall portions 44 is equal to an interval between two adjacent optical waveguides (core layer 32).
Two wall portions 44 adjacent to each other and the second lower cladding layer 42 among the plurality of wall portions 44 form guide groove portions 45. Each guide groove 45 guides the end 6 of each optical fiber 5 so that the position of the end 6 of each optical fiber 5 matches the position of the end 35 of each optical waveguide (core layer 32). In addition, each pair of side surfaces 43 and each bottom surface 41 is formed.
The distance between the two side surfaces 43 facing each other among the side surfaces 43 of the two wall portions 44 adjacent to each other is such that the optical fiber 5 can be smoothly inserted between the two side surfaces 43 facing each other. It is preferably equal to or slightly wider than the outer diameter. In other words, the pair of side surfaces 43 are preferably formed at positions facing each other with the optical fibers 5 interposed therebetween.

As shown in FIG. 2, each of the plurality of inclined surfaces 46 is a part of the plurality of bottom surfaces 41. Therefore, each of the plurality of bottom surfaces 41 includes a plurality of inclined surfaces 46 formed between each pair of side surfaces 43. The inclined surface 46 is a portion of the bottom surface 41 where a step is generated in the second lower cladding layer 42 by the step portion 60. The shape of the inclined surface 46 is a curved surface convex toward the core layer 32 or a curved surface convex toward the core layer 32 having one inflection point.
As each inclined surface 46 advances in the insertion direction X in which each optical fiber 5 is inserted into each guide groove 45 along each pair of side surfaces 43 and each bottom surface 41, the end 6 of each optical fiber 5 is connected to each optical waveguide ( It is a tapered surface formed so as to be optically connected to the end portion 35 of the core layer 32). In other words, the distance between the inclined surface 46 and the upper surface 22a of the substrate 20 increases as the direction of insertion X increases. Each inclined surface 46 is preferably a surface that gradually rises above the upper surface 22a of the substrate 20 in the insertion direction X.

  As shown in FIG. 2, the step portion 60 is formed between the second lower cladding layer 42 and the upper surface 22 a of the substrate 20 in order to form a plurality of inclined surfaces 46. As shown in FIG. 1, the step portion 60 viewed from above the substrate 20 has a shape in which the periphery of the upper surface 22a of the substrate 20 (the edge portion of the upper surface 22a of the substrate 20) is exposed. The shape of the stepped portion 60 is, for example, a shape obtained by reducing the shape of the upper surface 22a of the substrate 20. The material of the stepped portion 60 may be the same as that of the second lower cladding layer 42, for example.

As shown in FIG. 3, the upper guide portion 47 is formed on the upper surface 44 a of the two wall portions 44 located on the outermost side among the plurality of wall portions 44. Therefore, the upper guide portion 47 has the same width dimension as the distance between the two outermost wall portions 44 among the plurality of wall portions 44. The lid member 50 is formed in a plate shape, for example, so as to cover the openings of the plurality of guide groove portions 45 on the upper surfaces 44 a of the plurality of wall portions 44, and is supported by the plurality of wall portions 44.
The lower side of the lid member 50 has a plurality of pressing surfaces 48 formed between each pair of side surfaces 43. The plurality of pressing surfaces 48 are positioned so as to face the bottom surfaces 41 with the optical fibers 5 interposed therebetween. Each pair of side surfaces 43, each bottom surface 41, and each pressing surface 48 form a plurality of insertion holes 49 into which the end portions 6 of the respective optical fibers 5 are inserted. Therefore, since the end 6 of each optical fiber 5 is inserted into each insertion hole 49, each optical fiber 5 is connected to each bottom surface 41 and each holding surface 48 between each bottom surface 41 and each holding surface 48. It is preferable that the outer diameter of each optical fiber 5 is the same as or slightly larger than the outer diameter of each optical fiber 5.

  As shown in FIG. 2, each insertion hole 49 has an inclined surface 46, so that the end 6 of each optical fiber 5 is optically connected to the end 35 of each optical waveguide (core layer 32) as it advances in the insertion direction X. A trumpet shape is formed so that it can be connected to. Since the inclined surface 46 is located below the insertion hole 49, the insertion hole 49 is arranged such that the lower side of the insertion hole 49 rises above the insertion hole 49 (center side of the insertion hole 49) as it advances in the insertion direction X. The size of the insertion hole 49 is reduced. Therefore, even if the end 6 of the optical fiber 5 to be inserted into the insertion hole 49 hangs down due to its own weight, the opening on the insertion side of the insertion hole 49 is wide, and the insertion hole 49 on the optical waveguide (core layer 32) side is also wide. Since the opening faces the end portion 35 of the optical waveguide (core layer 32), the end portion 6 of the suspended optical fiber 5 can be smoothly guided to the end portion 35 of the optical waveguide (core layer 32). In other words, the alignment tolerance when connecting the plurality of optical waveguides (core layer 32) and the plurality of optical fibers 5 can be secured by the plurality of insertion holes 49.

The above optical waveguide substrate 10 can be manufactured as follows.
First, a method for manufacturing a material such as a film constituting the optical waveguide substrate 10 will be described.
[Preparation of resin film for forming clad layer]
[(A) Base polymer; production of (meth) acrylic polymer (A-1)]
46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate were weighed in a flask equipped with a stirrer, a cooling pipe, a gas introduction pipe, a dropping funnel, and a thermometer, and stirred while introducing nitrogen gas. . The liquid temperature was raised to 65 ° C., 47 parts by weight of methyl methacrylate, 33 parts by weight of butyl acrylate, 16 parts by weight of 2-hydroxyethyl methacrylate, 14 parts by weight of methacrylic acid, 2,2′-azobis (2,4-dimethylvaleronitrile ) A mixture of 3 parts by mass, 46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate was added dropwise over 3 hours, followed by stirring at 65 ° C. for 3 hours, and further stirring at 95 ° C. for 1 hour. A (meth) acrylic polymer (A-1) solution (solid content: 45% by mass) was obtained.

[Measurement of weight average molecular weight]
The result of having measured the weight average molecular weight (standard polystyrene conversion) of (A-1) using GPC (Brand name "SD-8022", "DP-8020" and "RI-8020", the Tosoh Corporation make). 3.9 × 10 ⁴ . In addition, the brand name "Gelpack GL-A150-S" and "Gelpack GL-A160-S" (made by Hitachi Chemical Co., Ltd.) were used for the column.

[Measurement of acid value]
As a result of measuring the acid value of (A-1), it was 79 mgKOH / g. In addition, the acid value was computed from the amount of 0.1 mol / L potassium hydroxide aqueous solution required for neutralizing the (A-1) solution. At this time, the point at which the phenolphthalein added as an indicator changed color from colorless to pink was defined as the neutralization point.

[Preparation of resin varnish for forming clad layer]
(A) As a base polymer, (A-1) 84 parts by mass (solid content: 45% by mass) (solid content: 38% by mass), (B) urethane (meth) acrylate having a polyester skeleton as a photocuring component ( Product name "U-200AX", manufactured by Shin-Nakamura Chemical Co., Ltd.) 33 parts by mass, and urethane (meth) acrylate having a polypropylene glycol skeleton (trade name "UA-4200", manufactured by Shin-Nakamura Chemical Co., Ltd.) 15 masses (C) As a thermosetting component, a polyfunctional block isocyanate solution in which an isocyanurate type trimer of hexamethylene diisocyanate is protected with methyl ethyl ketone oxime (solid content: 75% by mass) (trade name “Sumijour BL3175”, Sumika Bayer) Urethane Co., Ltd.) 20 parts by mass (solid content 15 parts by mass), (D) photopolymerization initiator 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name “Irgacure 2959”, manufactured by Ciba Japan Co., Ltd.), 1 part by mass of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (trade name “Irgacure 819”, manufactured by Ciba Japan Co., Ltd.) and 23 parts by mass of propylene glycol monomethyl ether acetate as an organic solvent for dilution are stirred. While mixing. Using a polyflon filter having a pore size of 2 μm (trade name “PF020”, manufactured by Advantech Toyo Co., Ltd.), the resultant was depressurized and degassed under pressure to obtain a resin varnish for forming a cladding layer.
Using the coating machine, the resin composition for forming a clad layer obtained above on a non-treated surface of a PET film (trade name “Cosmo Shine A4100”, manufactured by Toyobo Co., Ltd., thickness 50 μm) After coating and drying at 100 ° C. for 20 minutes, a surface release treatment PET film (trade name “Purex A31”, manufactured by Teijin DuPont Films, Inc., thickness 25 μm) is pasted as a protective film, and a resin film for forming a clad layer is applied. Obtained. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine. In this embodiment, the thickness of the first lower cladding layer and the lower guide layer (adhesive layer) used is as follows. Described in the Examples. Moreover, the film thickness after hardening of a 1st lower clad layer and a lower guide layer and the film thickness after coating were the same. The film thickness of the upper clad layer forming resin film used in this example is also described in the examples. The film thickness of the upper clad layer forming resin film described in the examples is the film thickness after coating.

[Preparation of resin film for core layer formation]
(A) As a base polymer, 26 parts by mass of a phenoxy resin (trade name “Phenotote YP-70”, manufactured by Tohto Kasei Co., Ltd.), and (B) 9,9-bis [4- (2- Acrylyloxyethoxy) phenyl] fluorene (trade name “A-BPEF”, Shin-Nakamura Chemical Co., Ltd.) 36 parts by mass, and bisphenol A type epoxy acrylate (trade name “EA-1020”, Shin-Nakamura Chemical Co., Ltd.) ) 36 parts by mass, (C) As a photopolymerization initiator, 1 part by mass of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (trade name “Irgacure 819”, manufactured by Ciba Specialty Chemicals Co., Ltd.) And 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one Product name “Irgacure 2959”, manufactured by Ciba Specialty Chemicals Co., Ltd.) 1 part by mass, and using the same method and conditions as in the above production example except that 40 parts by mass of propylene glycol monomethyl ether acetate was used as the organic solvent. Resin varnish B was prepared. Thereafter, pressure filtration and degassing under reduced pressure were performed under the same method and conditions as in the above production example.
The core layer-forming resin varnish B obtained above is applied to the non-treated surface of a PET film (trade name “Cosmo Shine A1517”, manufactured by Toyobo Co., Ltd., thickness 16 μm) in the same manner as in the above production example. After coating and drying, a release PET film (trade name “Purex A31”, manufactured by Teijin DuPont Films, Inc., thickness 25 μm) is applied as a protective film so that the release surface is on the resin side to form a core layer A resin film was obtained. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine, and the core layer forming resin film thickness used in this example is described in the following examples. Describe. The film thickness of the core layer forming resin film described in the examples is the film thickness after coating.

A method for manufacturing the optical waveguide substrate 10 will be described with reference to FIGS.
(Formation of Substrate 20: Electric Wiring Formation by Subtractive Method: FIGS. 4 and 5)
As shown in FIG. 4, a polyimide film 23 with a single-sided copper foil as the metal layer 24 ((polyimide: trade name “UPILEX VT”, manufactured by Ube Nitto Kasei Co., Ltd., thickness 25 μm), (copper foil: trade name “NA”) -DFF ", manufactured by Mitsui Mining & Smelting Co., Ltd., thickness 9 μm)) on the copper foil surface, photosensitive dry film resist (trade name“ Photec ”, manufactured by Hitachi Chemical Co., Ltd., thickness 25 μm), roll laminator (product) Using a name “HLM-1500” (manufactured by Hitachi Chemical Technoplant Co., Ltd.) under the conditions of a pressure of 0.4 MPa, a temperature of 110 ° C., and a laminating speed of 0.4 m / min, an ultraviolet exposure machine (trade name “EXM” -1172 "(manufactured by Oak Manufacturing Co., Ltd.) through a negative photomask with a width of 50 μm from the photosensitive dry film resist side, ultraviolet rays ( The length 365nm) 120mJ / cm ² was irradiated, and to remove the dry film photoresist of unexposed portions of 0.1 to 5 wt% of sodium carbonate 35 ° C. in dilute solution. Then, using the ferric chloride solution, the copper foil of the exposed portion where the photosensitive dry film resist was removed was removed by etching, and then using a 1-10 wt% sodium hydroxide aqueous solution at 35 ° C. Then, the photosensitive dry film resist in the exposed portion was removed, and electric wiring 25 of L (line width) / S (gap width) = 60/65 μm was formed to obtain a flexible wiring board.

(Formation of Ni / Au plating)
Thereafter, the flexible wiring board is degreased, soft-etched, acid washed, immersed in a sensitizer for electroless Ni plating (trade name “SA-100”, manufactured by Hitachi Chemical Co., Ltd.) at 25 ° C. for 5 minutes and then washed with water. And immersed in an electroless Ni plating solution (trade name “ICP Nicolon GM-SD solution”, manufactured by Okuno Pharmaceutical Co., Ltd., pH 4.6) at 83 ° C. for 8 minutes to form a 3 μm Ni film, Was washed.
Next, 85 substitution gold plating solution (electroless gold plating treatment solution (trade name “HGS-500”, manufactured by Hitachi Chemical Co., Ltd., 100 mL) and potassium gold cyanide (1.5 g / L)) It was immersed for 8 minutes at 0 ° C. to form a 0.06 μm displacement gold film on the Ni film. Thereby, the board | substrate 20 which is a flexible wiring board with which the electric wiring 25 part without a coverlay film was coat | covered with plating of Ni and Au was obtained (refer FIG. 5).

(Formation of stepped portion 60: first step: FIG. 6)
A plate-like step portion 60 is formed on the upper surface 22a of polyimide (Kapton EN) having a thickness of 25 μm as the substrate 20. The resin for forming the lower guide layer having a thickness of 15 μm is evacuated to 500 Pa or less using a vacuum pressure laminator (trade name “MVLP-500”, manufactured by Meiki Seisakusho Co., Ltd.), and then pressure 0.4 MPa, temperature Thermocompression bonding was performed under the conditions of 110 ° C. and a pressurization time of 30 seconds, and the laminate was laminated on the upper surface 22 a of the substrate 20. Furthermore, after irradiating 150 mJ / cm ² with ultraviolet rays (wavelength 365 nm) using a negative photomask, patterning is performed using a developer (1% aqueous potassium carbonate solution), and heating drying and curing at 170 ° C. for 1 hour. The step portion 60 was formed on the upper surface 22 a of the substrate 20. Thereby, the center of the upper surface of the member in which the substrate 20 and the stepped portion 60 are integrated has a convex shape.

(Formation of the second lower cladding layer 42: second step: FIG. 7)
The 10 μm-thick clad layer-forming resin film obtained above is used as an adhesive layer, and is cut into a size of 100 × 100 mm, and is a protective PET release film (trade name “Purex A31”, Teijin DuPont Films Ltd. Product), and using a vacuum pressure laminator (trade name “MVLP-500”, manufactured by Meiki Seisakusho Co., Ltd.) as a flat plate laminator on the polyimide surface of the substrate 20 which is the flexible wiring board formed above. After evacuating to 500 Pa or less, the second lower cladding layer 42 was formed on the substrate 20 by thermocompression bonding under conditions of a pressure of 0.4 MPa, a temperature of 100 ° C., and a pressurization time of 30 seconds. An ultraviolet exposure machine (trade name “EXM-1172”, manufactured by Oak Manufacturing Co., Ltd.) was irradiated with 4 J / cm ^{2 of} ultraviolet rays (wavelength 365 nm) from the carrier film side, and then the carrier film was peeled off, and 170 ° C. for 1 hour. A second lower cladding layer 42 having a thickness of 10 μm was formed on the substrate 20 by heat treatment.

(Formation of the first lower cladding layer 31: FIG. 8)
A resin film for forming a first lower clad layer having a thickness of 15 μm was cut into a size of 100 × 100 μm, the protective film was peeled off, and laminated on the second lower clad layer 42 by a vacuum laminator under the same conditions as described above. . The film was laminated from the carrier film side with an ultraviolet exposure machine (trade name “EXM-1172”, manufactured by Oak Manufacturing Co., Ltd.) through a negative photomask having 95 μm × 3.0 mm × 4 non-exposed portions. (1) The lower clad layer forming resin film was irradiated with ultraviolet rays (wavelength 365 nm) at 250 mJ / cm ² . Thereafter, the carrier film was peeled off, and the first lower cladding layer 31 was etched using a developer (1% potassium carbonate aqueous solution). Subsequently, the substrate was washed with water, dried and cured by heating at 170 ° C. for 1 hour, and the first lower cladding layer 31 having an opening of 95 μm × 3.0 mm formed in the optical fiber groove forming portion was formed on the substrate 20. Thereby, the first lower cladding layer 31 is formed in the portion where the core layer 32 which is an optical waveguide is formed, and the first lower cladding layer 31 is not present in the portion where the optical fiber 5 is mounted. .

(Formation of the core layer 32 and the wall part 44: 3rd process: Fig.9 (a) and (b))
Next, on the surface of the first lower cladding layer 31, a roll laminator (trade name “HLM-1500”, manufactured by Hitachi Chemical Technoplant Co., Ltd.) is used, pressure 0.4 MPa, temperature 50 ° C., laminating speed 0.2 m. / Min is used to laminate a 50 μm-thick core layer forming resin film from which the protective film has been peeled off, and then using the above-described vacuum pressure laminator (trade name “MVLP-500”, manufactured by Meiki Seisakusho Co., Ltd.) Then, after vacuuming to 500 Pa or less, thermocompression bonding was performed under the conditions of a pressure of 0.4 MPa, a temperature of 70 ° C., and a pressurization time of 30 seconds. Thereafter, the core pattern width for optical signal transmission is 50 μm (pattern pitch of the optical fiber connection part is 125 μm, the pattern pitch of the optical path conversion mirror forming part (5 mm point from the optical fiber connection part) is 4 μm), and the core pattern width for the fiber guide is 40 μm. A groove formed by the wall portion 44 which is a fiber guide core pattern is formed on the second lower cladding layer 42 through a negative photomask having a fiber groove pitch of 125 μm, four pieces, and a fiber guide core pattern on both ends only 150 μm. On top (see FIG. 9 (a)), alignment is performed so that the core layer 32 serving as the optical signal transmission core pattern is formed on the first lower cladding layer 31 (see FIG. 9 (b)). UV (wavelength 365nm) 700mJ / cm ² was irradiated by the ultraviolet exposure machine, then heated for 5 minutes after exposure at 80 ° C. I went. Thereafter, the PET film as the carrier film was peeled off, and the core pattern was etched using a developer (propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 8/2, mass ratio). Subsequently, the substrate is cleaned using a cleaning liquid (isopropanol), and heated and dried at 100 ° C. for 10 minutes to form a core layer 32 that is a core pattern for optical signal transmission and a wall portion 44 that is a core pattern for fiber guide, A groove having a width of 85 μm capable of accommodating the optical fiber 5 was formed. The size of each pattern in the wall portion 44 that is the fiber guide core pattern is such that when the optical fiber 5 is fixed in the groove, the optical fiber transmits and receives optical signals to the core layer 32 that is the optical signal transmission core pattern. Designed to join where possible.

(Formation of the upper clad layer 33: FIGS. 10A and 10B)
Next, the 85 μm-thick upper clad layer resin film from which the protective film has been peeled is applied to the upper surface 44a of the core layer 32 and the upper surface 44a of the wall 44 from the core pattern forming surface side. "", Manufactured by Meiki Seisakusho Co., Ltd.), and vacuum evacuated to 500 Pa or less, and then thermocompression bonded under the conditions of a pressure of 0.4 MPa, a temperature of 110 ° C., and a pressurization time of 30 seconds to laminate. Further, after irradiating 150 J / cm ² with ultraviolet rays (wavelength 365 nm) using the negative photomask used when the first lower cladding layer 31 was formed, the carrier film was peeled off, and the developer (1% potassium carbonate aqueous solution) ) Was used to etch the upper clad layer forming resin film in the groove formed by the two adjacent wall portions 44. Subsequently, the substrate was washed with water, dried by heating at 170 ° C. for 1 hour, and cured, whereby the first lower cladding layer 31, the core layer 32 that is an optical waveguide, and the upper cladding layer 33 were formed on the substrate 20.
As described above, the optical waveguide substrate 10 for a 4-channel was produced with a 125-μm pitch, a fiber diameter of 80 μm.
In the obtained optical waveguide substrate 10, the lateral width of the groove formed by the two adjacent wall portions 44 is 85 μm, and the height of the wall portion 44 (on the upper side of the step portion 60, the wall extends from the surface of the second lower cladding layer 42. 64 mm, the height from the upper surface 22 a of the substrate 20 to the upper surface of the upper cladding layer 33 is 85.5 μm, and the thickness of the core layer 32 that is an optical signal transmission core pattern is 50 μm. Met.

(Formation of slit groove 36: FIGS. 11A and 11B)
In order to smooth the optical fiber connection end face of the obtained optical waveguide substrate 10, a slit groove 36 having a width of 40 μm was formed using a dicing saw (trade name “DAC552”, manufactured by Disco Corporation) (FIG. 11). (See (a) and (b)). At the same time, the substrate is cut parallel to the fiber guide core pattern (3 mm from the end face of the optical waveguide), and a groove for mounting the optical fiber 5 on the end face of the substrate (formed by two adjacent wall portions 44). The outer shape was processed so that a groove) appeared. When the upper clad layer 33 is divided by the slit groove 36, the upper clad layer located above the wall portion 44 in the upper clad layer 33 becomes the upper guide portion 47.

(Formation of optical path conversion mirror 37: fourth step: FIGS. 11A and 11B, FIG. 12)
Using a dicing saw (trade name “DAC552”, manufactured by Disco Corporation) from the upper clad layer 33 side of the obtained optical waveguide substrate 10, the 45 ° optical path conversion mirror 37 is formed on the core layer 32 which is an optical waveguide. It formed (refer FIG. 11 (a) and (b)). Next, a metal mask having an opening in the optical path conversion mirror 37 is placed on the optical path conversion mirror 37, and Au is evaporated by 0.5 μm using a vapor deposition apparatus (trade name “RE-0025”, manufactured by First Giken Co., Ltd.). In this way, a vapor deposition metal layer 37a was formed on the optical path conversion mirror 37 (see FIG. 12).

(Formation of cover 50: Fourth step: FIG. 13)
Thereafter, protection of the 10 μm-thick clad layer-forming resin film obtained above as an adhesive layer 50 b of the lid 50 on the polyimide film (trade name “UPILEX RN”, manufactured by Ube Nitto Kasei Co., Ltd., thickness 25 μm) 50 a The film was peeled off and laminated with a vacuum laminator under the same conditions as above to form a lid member 50 having an adhesive layer 50b. Next, the carrier film of the clad layer forming resin film laminated on the lid member 50 is peeled off, and the peeled lid member 50 is placed on the upper clad layer 33 of the optical waveguide substrate 10. From the formed side, thermocompression bonding was performed with a vacuum laminator under the same conditions as described above. Next, the optical waveguide substrate 10 provided with the lid member 50 was formed by heating and curing at 180 ° C. for 1 h. The height of the optical fiber mounting groove from the surface of the optical waveguide substrate 10 (first lower clad layer 31) to the bottom surface of the lid member 50 (the bottom surface of the adhesive layer 50b of the lid member 50) was 82 μm.

  As mentioned above, although preferred embodiment was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above. For example, in this embodiment, the upper guide portion 47 may be omitted from the optical waveguide substrate 10. In the method for manufacturing the optical waveguide substrate 10, the fourth step may be omitted.

5 Optical fiber 6 Optical fiber end 10 Optical waveguide substrate 20 Substrate 22 Upper surface 30 of substrate Optical waveguide group 31 First lower clad layer 32 Core layer (optical waveguide)
33 Upper clad layer 35 End portion 36 of core layer (optical waveguide) Slit groove 40 Guide portion 41 Bottom surface 42 Second lower clad layer (lower guide layer)
42a Upper surface 43 of the second lower cladding layer Side surface 44 of the wall portion 44a Wall portion 44a Upper surface 45 of the wall portion 46 Guide groove portion 46 Inclined surface 47 Upper guide portion 48 Holding surface 49 of the lid material 50 Insertion hole 50 Lid material 60 Step portion 60a Step portion Top

Claims (6)

An optical waveguide substrate to which a plurality of cable-shaped optical elements are connected,
A plate-like substrate;
A plurality of optical waveguides formed above the upper surface of the substrate, each of which is optically connected to an end of each optical element; and
A guide part formed above the upper surface of the substrate,
The guide portion includes a plurality of wall portions forming a plurality of pairs of side surfaces, and a lower guide layer having a plurality of bottom surfaces,
The plurality of wall portions and the lower guide layer each form a plurality of guide groove portions for guiding an end portion of each optical element,
Each guide groove is formed so that the position of the end of each optical element matches the position of the end of each optical waveguide,
Each guide groove is formed by each pair of side surfaces and each bottom surface,
Each pair of side surfaces is formed at a position facing each other with each optical element interposed therebetween,
The plurality of optical elements are optically connected to the ends of the optical waveguides as the optical elements advance in the insertion direction inserted into the guide grooves along the pair of side surfaces and the bottom surfaces. Each includes a plurality of inclined surfaces formed between each pair of side surfaces,
Each inclined surface is an optical waveguide substrate having a convex curved upper portion on each optical element side when each optical element is inserted into each guide groove.   The optical waveguide substrate according to claim 1, wherein a distance between the inclined surface and the upper surface of the substrate increases as the distance increases. The guide portion has a cover material that covers the openings of the plurality of guide groove portions on the upper surfaces of the plurality of wall portions,
The lower side of the lid member has a plurality of pressing surfaces formed between each pair of side surfaces,
Each holding surface is positioned so as to face each bottom surface with each optical element in between,
Each pair of side surfaces, each bottom surface and each pressing surface form each insertion hole,
The optical waveguide substrate according to claim 1, wherein an end portion of each optical element is inserted into each insertion hole .   The optical waveguide substrate according to claim 3, further comprising a plate-shaped step portion for forming the plurality of inclined surfaces between the lower guide layer and the upper surface of the substrate. It is a manufacturing method of the optical waveguide board according to claim 4,
A first step of forming the step on the upper surface of the substrate;
The upper surface of the substrate and the upper surface of the step portion are formed such that the upper surface of the lower guide layer forms a bottom surface and the upper surface of the lower guide layer forms an inclined surface by the step of the step portion. A second step of forming the lower guide layer;
A third step of forming the plurality of wall portions so as to form the plurality of pairs of side surfaces at intervals such that each bottom surface can be formed between the respective optical elements facing each holding surface ; A method of manufacturing an optical waveguide substrate, comprising:   Furthermore, the manufacturing method of the optical waveguide board | substrate of Claim 5 provided with the 4th process of forming the said cover material so that the opening of these guide groove parts may be covered on the upper surface of the said lower guide layer.

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