JP2014194516A - Manufacturing method of optical transmission substrate, and optical transmission substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method by which a through-hole substrate can be easily mounted on an optical transmission substrate, and an optical transmission substrate.SOLUTION: A manufacturing method of an optical transmission substrate of the present invention includes the steps of: arranging, on a substrate 2, an optical waveguide layer 3 having a core part 3b extending in a plane direction and clad layers 3a and 3c arranged around the core part 3b; arranging a resin member 6 on the optical waveguide layer 3; and exposing and developing the resin member 6 to form a positioning structure that is formed of a protrusion or has grooves in which a concave-convex structure 6a including recess parts is provided across one end to the other end.

Description

  The present invention relates to a method for manufacturing an optical transmission board and an optical transmission board.

  In recent years, in order to improve information processing capability, it has been studied to change electrical transmission between electronic devices to optical transmission. Therefore, a structure composed of an optical transmission board, a through-hole board, and an optical element is disclosed as an optical transmission module for optical transmission between electronic devices (see, for example, Patent Document 1). Here, the optical transmission board has an optical waveguide formed in a planar direction, and can transmit light in the planar direction. Further, the optical element is mounted on the through-hole substrate so that the emitted light is optically connected to the optical waveguide.

  It is known that such an optical transmission module uses a fitting structure made of a combination of, for example, a concave portion or a projection provided on both when a through-hole substrate is mounted on the optical transmission substrate.

JP 2008-241956

  In the research and development of such an optical transmission module, it is required to improve the productivity of the optical transmission module by making it easy to mount the through-hole substrate and the optical transmission substrate.

  The present invention has been conceived under the above circumstances, and an object thereof is to provide an optical transmission board manufacturing method and an optical transmission board capable of easily mounting a through-hole board. .

  The method for manufacturing an optical transmission substrate of the present invention includes a step of disposing an optical waveguide layer having a core portion extending in a planar direction on the substrate and a clad layer disposed around the core portion, and on the optical waveguide layer A step of arranging a resin member, and a step of forming a positioning structure having a groove formed by a protrusion or an uneven structure having a recess from one end to the other end by exposing and developing the resin member. .

  The method for manufacturing an optical transmission substrate of the present invention includes a step of disposing an optical waveguide layer having a core portion extending in a planar direction on the substrate and a clad layer disposed around the core portion, and on the optical waveguide layer A step of arranging a concavo-convex structure comprising a protrusion or having a concave portion, and a step of cutting a part of the concavo-convex structure and cutting the core portion along a straight line that overlaps the concavo-convex structure and the core portion. Have.

The optical transmission substrate of the present invention includes a substrate, a core portion formed on the substrate and extending in a planar direction, and a clad layer disposed around the core portion, and the core portion extends. An optical waveguide layer having a first groove part that divides the core part in the middle of the direction, and a positioning structure that is formed on the optical waveguide layer and that includes a protrusion or a recess, and the positioning structure is And a second groove portion along the dividing direction of the first groove portion.

  According to the method for manufacturing an optical transmission board of the present invention, it is possible to suppress a decrease in productivity even when a groove is formed in an uneven structure.

  Further, according to the optical transmission board of the present invention, since the grooves are formed in the protrusions, the through-hole board can be easily mounted when the through-hole board is mounted on the optical transmission board.

1 is a perspective view showing a schematic configuration of an optical transmission module including an optical transmission board according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the optical wiring board of FIG. 1 and corresponds to a cross section taken along the line A-A ′ of FIG. 1. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of an optical transmission board according to the present invention, where (a) corresponds to a plan view viewed from above, and (b) is a cross-sectional view taken along line BB ′ in (a). (C) is equivalent to sectional drawing when cut | disconnected by CC 'line | wire of (a). This corresponds to an enlarged cross-sectional view of a part of the optical transmission board shown in FIG. FIG. 9 shows a modification of the embodiment of the optical transmission board shown in FIG. 3, where (a) corresponds to a plan view seen from above, and (b) is cut along the line DD ′ in (a). It corresponds to a cross-sectional view at that time. FIG. 9 shows a modification of the embodiment of the optical transmission board shown in FIG. 3, (a) corresponds to a plan view seen from above, and (b) is cut along line EE ′ of (a). It corresponds to a cross-sectional view at that time. 4 shows one step of an embodiment of the method for manufacturing an optical transmission board of the present invention, which corresponds to a cross section taken along line C-C ′ of FIG. 3. 4 shows one step of an embodiment of the method for manufacturing an optical transmission board of the present invention, which corresponds to a cross section taken along line C-C ′ of FIG. 3. 1 shows one step of an embodiment (first embodiment) of a method for manufacturing an optical transmission board of the present invention, wherein (a) corresponds to a plan view of the optical transmission board viewed from above, and (b). Corresponds to part of the cross section when cut along the line FF ′ in FIG. 1 shows one step of an embodiment (second embodiment) of the method for manufacturing an optical transmission board of the present invention, and corresponds to a plan view of the optical transmission board viewed from above. 4 shows one step of an embodiment of the method for manufacturing an optical transmission board of the present invention, which corresponds to a cross section taken along line C-C ′ of FIG. 3.

An optical wiring board according to an embodiment of the present invention will be described below. As shown in FIGS. 1 to 3, the optical transmission substrate 1 according to the present embodiment includes a substrate 2, an optical waveguide layer 3, and protrusions 4. As shown in FIG. 1, the optical transmission board 1 is used as an optical transmission module 200 with a through-hole board 100 mounted thereon.

<Optical transmission module>
The through-hole substrate 100 has a through-hole 101 penetrating in the vertical direction (D1 and D2 directions). The inside of the through hole 101 may be a cavity, or an optical transmission structure including the core 120 and the clad 121 may be disposed. An optical element 150 is mounted on the through-hole substrate 100. As the optical element 150, for example, a light emitting device such as a surface emitting laser or a light receiving device such as a photodiode can be used. This optical element 150 and optical waveguide layer 3
Are optically connected by the through hole 101. In the present embodiment, a case where an optical transmission structure is arranged in the through hole 101 will be described.

As the clad 121, for example, an epoxy resin, a polyimide resin, a phenol resin, an acrylic resin, or the like can be used. The cladding 121 has a thickness direction (D1, D
An optical waveguide hole 121a penetrating in two directions) is provided. A plurality of optical waveguide holes 121 a may be formed inside the clad 121. Since a plurality of optical waveguide holes 121a are provided in the clad 121, a plurality of signals can be transmitted, so that the optical transmission module 200 can be reduced in size.

  A core 120 is provided in the optical waveguide hole 121a. The core 120 is made of a material having a higher refractive index than that of the clad 121. Examples of the diameter of the core 120 include a range of 1 μm to 300 μm. Since the core 120 is filled in the optical waveguide hole 121a, the core 120 has substantially the same diameter as the optical waveguide hole 121a, and is set according to the shape and size of the optical waveguide hole 121a.

  The driving of the optical element 150 is controlled by the control element 102. The optical element 150 and the control element 102 are electrically connected by an electric wiring 103 formed on the through-hole substrate 100. The optical element 150 and the control element 102 are mounted on the electrical wiring 103. Further, the through-hole substrate 100 is provided with a through conductor 104 therein.

As shown in FIG. 2, the through-hole substrate 100 is mounted on the wiring conductor 5 formed on the substrate 2 via the bump conductor 105. A hole 33 is provided in the optical waveguide layer 3 so that the wiring conductor 5 on the substrate 2 is exposed. The through conductor 104 may be made of any material that can be electrically connected. The bump conductor 105 can be made of a material that can be electrically connected and can fix the through-hole substrate 100 and the substrate 2. For example, a conductor material made of paste solder can be used.

A fitting structure is provided on the lower surface of the through-hole substrate 100. As the fitting structure, for example, a recess or a protrusion can be used. As the fitting structure, a projection or a recess can be selected depending on the fitting structure (positioning structure) formed on the optical transmission board 1. In the present embodiment, a recess 110 is provided on the lower surface of the through-hole substrate 100 as a fitting structure. On the other hand, the optical transmission board 1 is a case where a protrusion is provided as a fitting structure.

The through-hole substrate 100 is placed on the optical transmission substrate 1 so that the recess 110 is fitted to the protrusion 4. In this way, the optical transmission module 200 can be formed. In the optical transmission module 200, the optical element 150 is controlled by the control element 102, and the control element 102 is electrically connected to the wiring conductor 5 on the substrate 2 by the through conductor 104 and the bump conductor 105.

<Optical transmission board>
Next, each configuration of the optical transmission board 1 will be described.

  The thickness of the board | substrate 2 is provided so that it may become the range of 0.01 mm or more and 1 cm or less, for example. One side (D3, D4 direction or D5, D6 direction in FIG. 1) of the substrate 2 can be set to, for example, 1 cm or more and 10 cm or less.

The substrate 2 is made of a ceramic material or an organic material. As a specific ceramic material, for example, materials such as zirconia, alumina, silicon carbide, boron nitride, beryllia, low-temperature fired glass ceramic, mullite, glass ceramic, or silicon nitride can be used, and these may be used in combination. . On the other hand, when an organic material is used as the material of the substrate 2, for example, an epoxy resin, a bismaleimide-triazine resin, a cyanate resin,
Polyphenylene ether resin, aromatic polyamide resin, polyimide resin, or the like can be used.

  The substrate 2 may be a single layer substrate or a laminate in which a plurality of sub-substrates are stacked. As a material of the substrate 2, for example, a ceramic material or an organic material such as an epoxy resin can be used. In the present embodiment, as shown in FIG. 3, a substrate made of a single layer ceramic material is employed. A wiring conductor 5 connected to an electric circuit or the like is formed on the substrate 2. The wiring conductor 5 is made of, for example, metallized metal.

  An optical waveguide layer 3 is formed on the substrate 2. For the optical waveguide layer 3, for example, a material based on an epoxy resin, an acrylic resin, and a polyimide resin can be used. The thickness of the optical waveguide layer 3 can be set to be, for example, 50 μm or more and 1 mm or less.

The optical waveguide layer 3 has a first cladding layer 3a and a second cladding layer 3c including a core portion 3b. Specifically, the refractive index of the core portion 3b is set to be larger in the range of 0.8% to 4% than the refractive indexes of the first cladding layer 3a and the second cladding layer 3c. Since the first cladding layer 3a and the second cladding layer 3c are disposed around the core portion 3b, light can be confined in the core portion 3b and light can be transmitted.

  The optical waveguide layer 3 has a first groove 3 'that divides the core 3b in the middle of the direction in which the core 3b extends. The first groove 3 'is formed, for example, in a direction perpendicular to the extending direction (D5, D6 direction) of the core 3b. The first groove 3 'is provided up to the first cladding layer 3a, and the core 3b is divided. The first groove 3 ′ is provided so that the width in the extending direction is, for example, not less than 10 μm and not more than 1 mm.

  As shown in FIG. 4, the core portion 3b divided in the first groove portion 3 ′ has an end surface 3ba parallel to the thickness direction of the optical waveguide layer 3, and an inclined surface inclined with respect to the extending direction of the core portion 3b. 3bb is exposed. The inclined surface 3bb is inclined by 45 °, for example, with respect to the extending direction of the core portion 3b. Since the core portion 3b has the end surface 3ba and the inclined surface 3bb, the light passing through the core portion 3b is emitted from the end surface 3ba and then reflected by the inclined surface 3bb in the thickness direction of the optical waveguide layer 3 to change the optical path. can do. The inclination angle of the inclined surface 3bb with respect to the extending direction can be set to be 40 ° or more and 52 ° or less, for example.

  The inclined surface 3bb may expose the core portion 3b, or may form a reflective film on the upper surface. The material of the reflective film may be selected in consideration of the reflectance depending on the wavelength of light to be transmitted. For example, a material mainly composed of aluminum, silver, gold, or the like can be used. By forming the reflective film, the light whose optical path is changed can be easily totally reflected.

A hole 33 is formed in the optical waveguide layer 3. The hole 33 is formed so as to be inside the wiring conductor 5 in plan view. By forming the hole 33 so as to be inside the wiring conductor 5, when the bump conductor 105 is provided in the hole 33 and reflowing is performed, the bump conductor 105 can be prevented from flowing to an unnecessary portion. .

A positioning structure is formed on the optical waveguide layer 3. The positioning structure can be a protrusion or a recess, and is selected according to the shape of the fitting structure provided on the lower surface of the through-hole substrate 100. In this embodiment, the projection 4 is used as the positioning structure. The thickness of the protrusion 4 can be set to 100 μm or more and 1 mm or less, for example. The width of the protrusion 4 in plan view can be set to be, for example, 10 μm or more and 2 mm or less. As for the external shape of the protrusion 4, the cross-sectional area with respect to the thickness direction becomes smaller toward the tip so that the side surface is inclined. Specifically, for example, the projection 4 can be formed in a polygonal pyramid shape such as a quadrangular pyramid shape, a polygonal frustum shape such as a quadrangular frustum shape, a conical shape, or a truncated cone shape. This embodiment demonstrates the case where the processus | protrusion 4 is formed in the column shape.

  The protrusion 4 is provided with a second groove portion 4 ′ along the dividing direction of the first groove portion 3 ′. The depth of the second groove 4 ′ may be provided up to the lower part of the protrusion 4 (the part in contact with the optical waveguide layer 3), or may be up to the middle of the protrusion 4 in the thickness direction. The width of the second groove 4 'can be set to the same width as the first groove 3', for example.

  As shown in FIG. 3A, the second groove 4 ′ may be provided from one end to the other end along the dividing direction of the first groove 3 ′ in a plan view. ) As shown in FIG.

Since the optical transmission board of the present embodiment has the second groove 4 ′ in the protrusion 4, when the through-hole substrate 100 is mounted on the optical transmission board 1 by fitting the recess 110 and the protrusion 4, Second groove 4 '
Air can be easily removed from the air. As a result, the through-hole substrate 100 can be easily mounted on the optical transmission substrate 1.

Further, since the second groove portion 4 ′ is provided along the first groove portion 3 ′, air that has escaped from the second groove portion 4 ′ when the through-hole substrate 100 is mounted is transferred to the first groove portion 3 ′. Easy to flow in the direction. Therefore, when the bump conductor 105 is melted by reflow and the optical transmission board 1 and the through-hole board 100 are fixed, even if the flux material to be applied before the bump conductor 105 is mounted is vaporized, the vicinity of the first groove 3 ' Since the air that has escaped from the second groove 4 ′ flows, the flux can hardly be attached or deposited on the surfaces of the end surface 3ba and the inclined surface 3bb of the core 3b.

  Further, when air flows in the direction of the first groove 3 ′, minute deposits (particles in the air, etc.) attached to the surfaces of the end surface 3ba and the inclined surface 3bb located in the first groove 3 ′ are removed. The effect is easy. Further, as shown in FIG. 3, when the first groove 3 ′ is provided from one end to the other end of the optical waveguide layer 3 along the dividing direction, the air escaped from the second groove 4 ′ is the optical waveguide. It becomes easy to be discharged out of the layer 3. As a result, the adhering portion can be easily discharged out of the optical waveguide layer 3.

(Modification 1 of optical transmission board)
As shown in FIG. 5B, the second groove portion 4 ′ is provided up to the lower end of the protrusion 4, and the optical waveguide layer 3 has a third groove portion 3′a continuous with the second groove portion 4 ′. May be. Such 3rd groove part 3'a is formed so that it may become the same width as 2nd groove part 4 '. The depth of the third groove 3′a is not particularly limited as long as it is within the optical waveguide layer 3. The third groove portion 3′a is not only continuous with the second groove portion 4 ′ but also arranged so as to be continuous with the first groove portion 3 ′.

By having the third groove portion 3′a, when the through-hole substrate 100 is mounted, the air that has escaped from the second groove portion 4 ′ can easily flow to the first groove portion 3 ′ side. Thereby, it is possible to easily remove deposits attached to the end surface 3ba and the inclined surface 3bb of the core portion 3b. As a result, the generation of stray light due to the deposit can be suppressed.

  In addition, by having the third groove portion 3′a, the air that has escaped from the second groove portion 4 ′ can easily flow into the first groove portion 3 ′ after flowing into the third groove portion 3′a. . As described above, since air easily flows into the first groove portion 3 ′, the generation of stray light due to the deposit can be further suppressed.

(Modification 2 of optical transmission board)
The protrusion 4 may be arrange | positioned so that it may overlap with the core part 3b, as shown in FIG. In this modification, the protrusion 4 has a quadrangular prism shape. In this modification, a cylindrical shape or the like may be used as the protrusion 4. When a quadrangular prism shape is used as the protrusion 4, even if there is only one protrusion 4, it rotates in the plane direction (D 3, D 4 direction and D 5, D 6 direction) when the through-hole substrate 100 is mounted. Can be suppressed.

  The protrusion 4 may be disposed so as to overlap a part of the plurality of core portions 3b in plan view, or may be disposed so as to overlap all of the plurality of core portions 3b. Although only one protrusion 4 in FIG. 6 is provided so as to overlap all the core portions 3b, a plurality of protrusions 4 may be provided so as to overlap some core portions 3b. When the plurality of protrusions 4 are provided, the alignment accuracy can be improved and the through-hole substrate 100 can be prevented from rotating in the planar direction.

The second groove 4 ′ of the protrusion 4 is formed continuously with the first groove 3 ′ of the optical waveguide layer 3. As a result, the space of the second groove 4 ′ is surrounded by the protrusion 4, and when the through-hole substrate 100 is mounted, the air that escapes from the second groove 4 ′ is pushed downward. For this reason, it is possible to make it easier for the air that escapes from the second groove portion 4 ′ to flow into the first groove portion 3 ′. As a result, it is possible to further suppress the generation of stray light due to the attached matter.

Further, since the protrusion 4 is arranged so as to overlap the core portion 3b, the distance between the core portion 3b and the protrusion 4 can be shortened in a plan view, so that the alignment when the through-hole substrate 100 is mounted is achieved. Accuracy can be improved. Moreover, since the protrusion 4 is disposed so as to overlap the core portion 3b, the optical transmission board 1 can be reduced in size in the plane direction (D3, D4 direction and D5, D6 direction).

Further, when arranged so as to overlap with the core portion 3b in this way, the bump 4 is present when the through-hole substrate 100 is mounted and reflowed due to the presence of the protrusion 4 in the extending direction of the core portion 3b. Can be made difficult to flow into the first groove 3 '.

(Modification 3 of optical transmission board)
As shown in FIG. 6, the bottom side 4 ′ a of the second groove part 4 ′ may be inclined so that the core part 3 b side is lowered.

As described above, the second groove portion 4 ′ has the bottom 4′a inclined so that the core portion 3b side is lowered, so that air that escapes from the second groove portion 4 ′ when the through-hole substrate 100 is mounted. Can easily flow toward the core portion 3b. As a result, the generation of stray light can be further suppressed.

<Method for manufacturing optical transmission board>
A method for manufacturing the optical transmission board 1 according to an embodiment of the present invention will be described. The first embodiment is a manufacturing method for forming the positioning structure by photolithography, and the second embodiment is a manufacturing method for forming the positioning structure by cutting a part of the concavo-convex structure. The first embodiment is advantageous in that the positioning structure having the second groove portion can be formed in one step, and the second embodiment is advantageous in that the first groove portion and the second groove portion can be formed in one step.

(First Embodiment of Manufacturing Method of Optical Transmission Board)
The manufacturing method of the optical transmission board according to the first embodiment includes a step of arranging the optical waveguide layer 3 on the substrate 2, a step of arranging the resin member 6 on the optical waveguide layer 3, and a step of forming a positioning structure. ing. In the following, each process will be described separately.

(Process of placing the optical waveguide layer on the substrate)
An optical waveguide layer 3 is formed on the substrate 2. In the present embodiment, first, as shown in FIG. 7A, a clad film that becomes the first clad layer 3 a is laminated on the substrate 2. As a method for laminating the film to be the first cladding layer 3a, for example, a vacuum laminating method or a roll laminating method can be used. The film thickness of the first cladding layer 3a can be controlled by adjusting the film thickness of the film.

  Further, the first cladding layer 3a may be formed by spin coating. When the first clad layer 3a is formed by spin coating, the film is formed by spin coating a resin material to be the first clad layer 3a. In the case of the spin coating method, it can be controlled by adjusting the rotational speed or the viscosity of the resin material. Thereafter, the applied resin material becomes the first cladding layer 3a through natural drying or heat drying.

  Next, a film to be the core portion 3b is laminated on the first cladding layer 3a. If the film is a negative type material, after laminating, the portion that becomes the shape of the core portion 3b is exposed. Here, exposure is performed using light of a specific wavelength. Specifically, for example, a portion that becomes the core portion 3b is exposed using a light-transmitting plate having a light shielding portion other than the portion that becomes the core portion 3b. Then, the core part 3b can be formed in a specific shape by developing the exposed film.

  The development is performed by using the difference in solubility between the exposed portion and the unexposed portion. Thereby, as shown in FIG.7 (b), the core part 3b is formed. In addition, you may use the core part 3b using a positive film, and in that case, it exposes except the part used as the core part 3b.

  Finally, as shown in FIG. 7C, the second cladding layer 3c is formed so as to cover the core portion 3b. That is, the film to be the second cladding layer 3c is laminated so as to be thicker than the thickness of the core portion 3b and so as to cover the first cladding layer 3a and the second cladding layer 3c around the core portion 3b. Thereafter, exposure and heating are performed to form the second cladding layer 3c. In this way, the optical waveguide layer 3 can be formed on the substrate 2.

  Thereafter, a first groove 3 ′ is formed in the optical waveguide layer 3 by cutting a part of the core 3 b using a dicing blade or the like. As the dicing blade, an inclined surface 3bb is formed in the optical waveguide layer 3 by using a blade having an inclined surface inclined by about 45 ° with respect to the cutting direction.

(Process of placing resin member)
Next, a process for forming a positioning structure on the optical waveguide layer 3 will be described. Specifically, as shown in FIG. 8, a resin member 6 is formed on the optical waveguide layer 3. As the film forming method, for example, a spin coating method or the like can be used. By adjusting the film thickness of the resin member 6, the height of the protrusion 4 can be adjusted.

  Thereafter, by patterning the resin member 6, a positioning structure can be formed on the optical waveguide layer 3 as shown in FIG. 9. For patterning the resin member 6, for example, a dry etching method or a wet etching method can be used using a mask pattern. When a photosensitive material such as an epoxy resin is used as the resin member 6, an etching method using a difference in solubility due to exposure can be used.

Further, as a method for forming the resin member 6, the same material / formation method as that of the optical waveguide layer 3 may be used. That is, the positioning structure may be formed by laminating a film. When a positioning structure is formed by laminating films, for example, 20 μm or more and 60 μm
A plurality of the following films can be stacked. When the same material as the optical waveguide layer 3 is used, the positioning structure can be made difficult to peel off from the optical waveguide layer 3.

(Process for forming positioning structure)
Next, as shown in FIG. 9, the resin member 6 is exposed and developed to form a positioning structure. The positioning structure is configured to have a second groove portion that is formed of a protrusion or a concave-convex structure having a concave portion provided from one end to the other end. This embodiment is a case of a structure having a concave portion 8 as the concave-convex structure.

  The recessed part 8 is provided so that the planar view shape may be, for example, a circular shape or a polygonal shape. The lateral width of the recess 8 is provided to be, for example, 100 μm or more and 2 mm or less. The recess 8 is shaped by the presence of a part of the resin member 6. In the following description, a part of the resin member 6 is referred to as a recess constituting portion 6 ′.

  The recess 8 has a second groove 8 ′ provided from one end to the other end. Specifically, a second groove portion 8 'is provided in the concave portion forming portion 6'. The second groove 8 'is provided from one end constituting the recess 8 of the recess constituting part 6' to the other end which is the outer periphery of the recess constituting part 6 '. As a result, the recessed portion 6 'is connected to the outside of the recessed portion 8 and the recessed portion 6' by the second groove 8 '. The depth of the second groove portion 8 ′ may be up to the middle of the recess constituting portion 6 ′, or may be set so that the upper surface of the optical waveguide layer 3 is exposed.

  Such a positioning structure can be formed by exposing the resin member 6 to the pattern of the recess 8 having the second groove 8 '. The exposure is performed using a translucent plate having a light-shielding portion, as in the step of placing the optical waveguide layer 3 on the substrate 2. The translucent plate is set so that the shape of the light shielding portion is the shape of the concave portion constituting portion 6 ′ in plan view. This is because the concave portion 8 having the second groove portion 8 'is determined by the shape of the concave portion constituting portion 6'. In the case where a negative material is used as the resin member 6, it is only necessary to expose a portion that becomes the concave portion 6 ′.

  After the exposure, the resin member 6 is developed to form the recess constituting portion 6 ′ having a predetermined pattern. In the present embodiment, since the concave portion 8 has the second groove portion 8 ′, when developing the resin member 6, the developer passes from the inside of the concave portion 8 through the second groove portion 8 ′ to the concave portion 8 (recess portion configuration). Part 6 ') can be easily flowed out. As a result, it is possible to make it difficult for the developer to remain in the recess 8, and the shape of the recess 8 can be formed with high accuracy.

  In addition, as shown in FIG. 9, the first groove 3 ′ is provided from one end to the other end of the optical waveguide layer 3, and the second groove 8 ′ is provided along the first groove 3 ′. In this case, the developer can be easily discharged out of the optical transmission substrate 1. Note that the first groove 3 ′ and the second groove 8 ′ do not have to be along, but it is only necessary to have an intersection where the first groove 3 ′ and the second groove 8 ′ intersect. As a result, the developer present in the recess 8 flows out to the first groove 3 ′ through the second groove 8 ′ and the intersection, so that the developer can be easily discharged out of the optical transmission substrate 1. It is.

  In the present embodiment, the case where the second groove portion 8 ′ is provided along the first groove portion 3 ′ has been described, but the second groove portion 8 ′ may not be along the first groove portion 3 ′. Even if the second groove portion 8 ′ is not along the first groove portion 3 ′, it is possible to make it difficult for the developer to remain in the recess portion 8, so that the shape of the recess portion 8 can be formed with high accuracy.

(Second Embodiment of Manufacturing Method of Optical Transmission Board)
Next, a second embodiment of the method for manufacturing an optical transmission board will be described. In the following, each process will be described separately. 2nd Embodiment demonstrates the case where the processus | protrusion 4 is formed as a positioning structure. The process up to the step of arranging the optical waveguide layer 3 on the substrate 2 is the same as that of the first embodiment. After the step of disposing the optical waveguide layer 3 on the substrate 2, the step of forming the resin member 6 on the optical waveguide layer 3 is performed. In the first embodiment, the first groove 3 ′ is formed before the step of forming the resin member 6, whereas in the present embodiment, the first groove 3 ′ is formed before the step of forming the resin member 6. There is no need to form.

(Process for forming irregularities)
After the step of disposing the resin member 6, the resin member 6 is formed of a protrusion (protrusion 4 that does not have the second groove), or has a concave-convex structure (a recess that does not have the second groove). 6a is formed. In the following description, the protrusion may be referred to as the protrusion 6a for convenience. In the present embodiment, a case where the protrusion 6a is formed as the concavo-convex structure 6a will be described. The protrusion 6a can be formed using photolithography in the same manner as described above.

(Process for forming positioning structure)
Next, a process of forming a positioning structure that cuts a part of the protrusion 6a and cuts the core 3b will be described. FIG. 10 is a plan view of the substrate 2, the optical waveguide layer 3, and the protrusion 6a after the step of forming the irregularities. As shown in FIG. 10, along the straight line Li (dotted line in FIG. 10) that overlaps the protrusion 6a and the core 3b, a part of the protrusion 6a is cut and the core 3b is cut.

  For example, a rotary blade such as a dicing blade or a wire saw can be used to cut off a part of the protrusion 6a and cut the core 3b. In this embodiment, a case where a dicing blade is used will be described.

  As shown in FIG. 11A, the dicing blade 7 has the tip of the rotary blade inclined at an angle Ra with respect to the cutting direction Di. The inclination of this angle Ra becomes the inclination angle of the inclined surface 3bb of the core portion 3b. Therefore, the angle Ra is set to, for example, 40 ° or more and 52 ° or less.

  The dicing blade 7 is moved in the cutting direction Di while rotating, and a part of the protrusion 6a is cut off, and then the optical waveguide layer 3 is cut off. The dicing blade 7 is moved in the cutting direction Di until the tip (lower end) reaches the lower end of the core portion 3b. In this way, as shown in FIG. 11B, a part of the protrusion 4 is cut off and the core portion 3b is divided.

  The method for manufacturing an optical transmission board according to the present embodiment includes a step of forming a protrusion 4 with a part cut away, and a step of dividing the core portion 3 b of the optical waveguide layer 3. Therefore, even when the second groove portion 4 ′ is formed in the protrusion 4, an increase in the number of steps can be suppressed. In other words, since the second groove portion 4 ′ can be formed in the protrusion 4 when the core portion 3 b is divided, the number of steps can be reduced. As a result, productivity can be improved in the manufacture of the optical transmission board.

  This invention is not limited to the above embodiment, It can implement in a various aspect.

In the above-described embodiment, as a structure when the optical transmission module 200 is mounted on the optical transmission board 1, the case where the projection 4 is provided on the optical transmission board 1 and the recess 110 is provided on the through-hole board 100 is described. However, it is not limited to this. That is, the protrusion 4 and the recess 110 are an example of a combination of fitting structures. For example, the recess 8 may be provided on the optical transmission substrate 1 and the protrusion may be provided on the through-hole substrate 100.

DESCRIPTION OF SYMBOLS 1 Optical transmission board | substrate 2 Board | substrate 3 Optical waveguide layer 3a 1st cladding layer 3b Core part 3ba End surface 3bb Inclined surface 3c 2nd cladding layer 3 '1st groove part 3'a 3rd groove part 4 Protrusion 4' 2nd groove part 4'a Bottom 5 Wiring conductor 6 Resin member 6 'Concave portion 6a Protrusion portion 7 Dicing blade 8 Concave portion 8' Second groove portion 33 Hole 100 Through hole substrate 101 Through hole 102 Control element 103 Electric wiring 104 Through conductor 105 Bump conductor 110 Concave portion 120 Core 121 Clad 121a Optical waveguide hole 150 Optical element 200 Optical transmission module

Claims (9)

Disposing an optical waveguide layer having a core portion extending in a planar direction on the substrate and a clad layer disposed around the core portion;
Disposing a resin member on the optical waveguide layer;
And a step of forming a positioning structure having a groove formed of a protrusion or an uneven structure having a recess from one end to the other end by exposing and developing the resin member. Disposing an optical waveguide layer having a core portion extending in a planar direction on the substrate and a clad layer disposed around the core portion;
A step of arranging a concavo-convex structure consisting of protrusions or having recesses on the optical waveguide layer;
A method for manufacturing an optical transmission board, comprising: cutting a part of the concavo-convex structure and cutting the core part along a straight line overlapping the concavo-convex structure and the core part.   The method of manufacturing an optical transmission board according to claim 2, wherein the step of cutting out a part of the concavo-convex structure and cutting the core part is performed using a blade. A substrate,
A first portion that is formed on the substrate and has a core portion extending in a planar direction and a clad layer disposed around the core portion, and divides the core portion in the middle of the direction in which the core portion extends. An optical waveguide layer having a groove,
And a positioning structure made of a protrusion or having a recess formed on the optical waveguide layer, wherein the positioning structure has a second groove portion along a dividing direction of the first groove portion.   The optical transmission board according to claim 4, wherein the second groove portion is provided from one end to the other end of the positioning structure along the dividing direction in a plan view.   6. The optical transmission board according to claim 4, wherein the first groove is provided from one end to the other end of the optical waveguide layer along the dividing direction in a plan view.   The optical transmission according to claim 4, wherein the second groove portion is provided up to a lower end of the positioning structure, and the optical waveguide layer has the third groove portion that is continuous with the second groove portion. substrate.   The optical transmission board according to claim 4, wherein the protrusion is disposed so as to overlap the core portion. The positioning structure is arranged so that the core portion does not overlap,
The optical transmission board according to any one of claims 4 to 7, wherein a bottom side of the second groove part is inclined so that the core part side is lowered.

Images