JP2012203371A - Method for manufacturing mirror portion of optical waveguide using metal film, and optical waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method which is capable of easily forming a mirror portion of an optical waveguide.SOLUTION: A method for manufacturing an optical waveguide having an oblique mirror portion formed in at least one end of a core includes the steps of: forming a core groove in a lower clad layer; injecting a core material to fill the core groove and hardening the core material in the core groove; forming a laminate of the lower clad layer, the core and an upper clad layer; forming a V groove for an oblique mirror portion, which corresponds to an oblique mirror portion, in a direction orthogonal to a lengthwise direction of the laminate in contact with at least one end in the lengthwise direction of the laminate; depositing a metal film on a convex portion of a second mold having the convex portion capable of being brought into contact with a core-side slope of the V groove for an oblique mirror portion; depositing an adhesive on the slope of the V groove for an oblique mirror portion and/or the metal film surface of the second mold; forming a mirror portion by pressing the second mold having the metal film deposited thereon to the core-side slope of the V groove to stick the metal film to the slope of the V groove via the adhesive.

Description

  The present invention relates to a method for manufacturing a mirror part of an optical waveguide using a metal film, and an optical waveguide in which the mirror part is formed of a metal film.

  Along with the practical application of optical communication systems, the technology related to optical waveguides as its basic configuration has attracted attention. As an optical waveguide, a buried structure in which a core having a high refractive index is surrounded by a clad having a low refractive index is typically known. Light incident on the core of the optical waveguide propagates through the core while being reflected at the interface between the core and the clad.

  In an opto-electric hybrid board in which such an optical waveguide and an electronic circuit are mixedly mounted on a single substrate, an optical waveguide is formed on the opposite surface of the substrate having electrical wiring on the back surface, and 45 at both ends of the optical waveguide. The core of the optical waveguide is formed by forming a mirror and changing the optical path of the light emitted from the light emitting element mounted on the electric wiring side of the substrate at the position of one 45 ° mirror by changing the 90 ° optical path at the 45 ° mirror section. The light is received by a light receiving element mounted on the electric wiring side of the board at the position of the other 45 ° mirror. For example, Patent Document 1 shows an optoelectronic circuit board (opto-electric hybrid board) that is upside down from the above description, but changes the optical path of light emitted from a light emitting element by a mirror and propagates the light in the core of the optical waveguide. Has been.

  In order to form the 45 ° mirror part, after forming the lower clad, core and upper clad of the optical waveguide, the V-shaped groove for the 45 ° mirror part is diced using a triangular blade. It is common to perform V-groove processing with a saw (dicer) and form a metal film on the surface of the V-groove by vacuum deposition or the like. Grooves are formed.

  However, in the above conventional method, it is necessary to precisely control the processing position and processing depth of the blade, and the variation in the thickness of the clad affects the variation in the mirror position, so it is difficult to control the position accuracy. There was a problem of being. Further, in the cutting with the blade, when the core and the clad are relatively soft materials, there is a problem that the processed surface becomes rough and the light reflection efficiency is lowered. Further, heating is necessary to form a metal film in the V-groove by vacuum vapor deposition, but there is a problem that the resin constituting the clad material is softened and melted by the radiant heat at that time.

  On the other hand, Patent Document 2 describes a mold capable of simultaneously forming a core pattern and an oblique mirror portion. However, the technology for forming the metal film only on the oblique mirror part after the transfer is unclear, and usually a process of masking the part other than the mirror part is necessary. It is presumed that the process becomes complicated because it is necessary to perform bonding by alignment. Moreover, even if it refers to drawing, the positional relationship of the core pattern 14 and the diagonal mirror part 16 is strange, and a positional relationship of both cannot be understood.

  As a technique for solving the above problem, the present inventor has already proposed a technique for forming a metal film by applying a metal colloid solution to the inclined surface of the V-groove for the oblique mirror portion and performing a heat treatment (Patent Document 3). . However, since the metal colloid liquid is expensive, there is a problem that the manufacturing cost increases. In addition, when the V groove is formed by cutting with a dicer or the like, even if a metal film is formed because the surface properties are rough, the flatness of the processed surface may be poor. In this case, the surface is flattened. There is room for improvement from the viewpoint of cost reduction, such as the need for this process, which increases manufacturing costs.

JP 2008-250007 A JP 2002-31273 A JP 2011-13362 A

  The present invention has been made paying attention to the above-described circumstances, and an object of the present invention is to provide a manufacturing method capable of forming a mirror part of an optical waveguide that can easily solve the above problems.

  The present invention that has achieved the above object is a method of manufacturing an optical waveguide in which an oblique mirror portion is formed on at least one end of a core, and is a first mold having a convex portion corresponding to a core groove, Pressing the clad layer before curing formed thereon and curing the clad layer as it is to form a core groove in the lower clad layer; releasing the first mold from the lower clad layer; Injecting and filling the core material, and curing the core material in the core groove; after curing the core material, the upper cladding material is dropped onto the core and the lower cladding layer and cured to form the lower cladding layer Forming a laminated body of core, upper clad layer; forming a V-groove for an oblique mirror portion corresponding to the oblique mirror portion in a direction perpendicular to the contact with at least one end of the laminated body in the longitudinal direction ; For oblique mirrors A step of attaching a metal film to a convex part of the second mold having a convex part capable of coming into contact with the slope on the core side of the groove; on the slope of the V groove for the oblique mirror part and / or the surface of the second type metal film A step of attaching an adhesive; pressing the second mold to which the metal film is attached against the slope on the core side of the V-groove, and attaching the metal film to the slope of the V-groove via an adhesive to form a mirror portion An optical waveguide manufacturing method having a gist in including a process.

  As a preferred embodiment of the present invention, in the step of forming the core groove, the convex portion corresponding to the core groove and at least one end of the convex portion corresponding to the core groove are in contact with each other in a direction perpendicular to the convex portion corresponding to the core groove. 1A type having a convex portion corresponding to the extending oblique mirror portion, pressing the uncured cladding layer formed on the substrate, curing the cladding layer as it is, and forming the core groove and the oblique mirror in the lower cladding layer A step of forming a V-groove for part, and the step of curing the core material is to release the mold of the first A from the lower cladding layer, inject and fill the core material into the core groove, A step of curing the core material, and the step of forming the laminated body and the step of forming the V-groove are after the core material is cured and the upper clad material is applied on the core and the lower clad layer. , Diagonal in type 1A After pressing the type 1B mold having only the convex part of the same shape as the convex part corresponding to the collar part so that the convex part of the type 1B is in contact with the V groove of the lower clad layer, the upper clad material is It is also a desirable method for producing an optical waveguide, which is a step of forming a laminated body and forming a V-groove by curing.

  Further, the present invention is a method of manufacturing an optical waveguide in which an oblique mirror portion is formed on at least one end of a core, a convex portion corresponding to the core groove, and at least one end of the core groove corresponding convex portion, 1A mold having a convex portion corresponding to the oblique mirror portion extending in a direction perpendicular to the convex portion corresponding to the core groove, pressing the uncured cladding layer formed on the substrate, and curing the cladding layer as it is A step of forming a core groove and an oblique mirror V groove in the lower clad layer; releasing the mold 1A from the lower clad layer, injecting and filling a core material into the core groove, and forming a core in the core groove; A step of curing the material; a step of coating the upper clad material on the inclined surface, the core, and the lower cladding layer of the oblique mirror portion V-groove; It has a convex part that can contact Pressing a second mold having a metal film on the part so that the convex part comes into contact with the slope of the V-groove, and transferring the metal film to the surface of the upper clad material of the V-groove to form a mirror part; This is a method of manufacturing an optical waveguide having a gist of including a step of releasing the second mold after curing the clad material.

  As a preferred embodiment of the present invention, in the step of curing the core material, the first mold is released from the lower cladding layer, and the core material is injected and filled into the core groove and the V-groove for the oblique mirror portion. A lower clad layer in which the core groove and the V-groove for the oblique mirror portion are filled with the core material, and the step 1B having only the convex portion having the same shape as the convex portion corresponding to the oblique mirror portion in the step 1A It is also a desirable method of manufacturing an optical waveguide that is a step of pressing the convex portion of the type 1A against the V groove, removing the core material from the V groove, and then curing the core material in the core groove.

  In the present invention, it is also preferable that the metal film is at least one metal foil selected from the group consisting of gold, silver, copper, aluminum, and an alloy containing one or more of these.

  The optical waveguide of the present invention is an optical waveguide in which an oblique mirror portion is formed at least at one end of the core, and the mirror portion is formed by a metal foil.

  In the manufacturing method of the present invention, since the mirror part can be easily formed in the V groove for the oblique mirror part using the metal film, masking and a vacuum apparatus are not necessary and inexpensive compared with the vacuum evaporation method or the like. Since raw materials can be used, an optical waveguide having an oblique mirror portion can be manufactured easily and inexpensively.

  In addition, when the metal foil is formed on the oblique mirror portion through a clad material or an adhesive, the surface is flattened by the adhesive or the like, so that the processing surface that becomes a problem when the oblique mirror portion is formed by a dicer or the like is roughened. The problem of reduced light reflectivity can also be eliminated, simplifying the manufacturing process, improving production speed, and improving yield, resulting in lower optical waveguide costs. Is possible.

It is a perspective explanatory view of the 1st type. It is a figure explaining the usage method of a 1st type | mold. It is a perspective explanatory view of a lower cladding layer. It is a figure explaining an example of the laminated body in which V groove | channel was formed. It is a perspective explanatory view of other examples of the 1st type. It is a figure explaining an example of the method of forming V groove | channel with an upper clad material. 7A and 7B are perspective explanatory views of the type 1B. It is a figure explaining an example of the laminated body in which V groove | channel was formed. 9A and 9B are perspective explanatory views of the second mold. It is a figure explaining an example of the usage method of a 2nd type | mold. It is a perspective explanatory view of the type 1A. It is a figure explaining the usage method of a type | mold of 1A. It is a perspective explanatory view of a lower cladding layer. It is a figure explaining the usage method of a 1B type | mold. It is a figure explaining an example of the usage method of a 2nd type | mold. It is a figure explaining another example of the usage method of the 2nd type. It is explanatory drawing of a 2nd type | mold. It is a perspective explanatory view of the 2nd type which has an adsorption mechanism.

  The present invention is characterized in that the second mold is used to form the mirror part of the metal film on the inclined surface on the core side of the V groove for the oblique mirror part. For this reason, it does not specifically limit about the other process for manufacturing an optical waveguide. Hereinafter, although the manufacturing method of the optical waveguide in which the representative slanting mirror part was formed is demonstrated, the manufacturing method of the optical waveguide of this invention is not limited to the following example, It can change suitably.

<The manufacturing method 1 of the optical waveguide of this invention>
An example of a method of manufacturing an optical waveguide in which a metal film is formed on the core-side slope of the V groove for the oblique mirror portion using the second mold of the present invention will be described.

  As shown in FIG. 1, the core groove is formed in the lower clad layer using the first mold 1 having the convex portion 2A corresponding to the core groove. The core groove corresponding convex portion 2A is only one in the illustrated example, but a plurality of core groove corresponding convex portions may be formed in parallel (other manufacturing examples are also the same). FIG. 2 shows a cross-sectional view taken along line AA in a state where the first mold 1 of FIG. 1 is turned upside down. The lower clad layer 3A before curing is produced on the substrate 4 by a known method, and as shown in FIG. 2, the first mold 1 is turned upside down from FIG. 1 and pressed against the lower clad layer 3A. After releasing the first mold 1 by curing the lower clad layer 3A while pressing the first mold 1, the core groove 2B is formed as shown in a perspective view in FIG. The later lower cladding layer 3 is obtained.

  Next, the core material is filled into the core groove 2B by a known method. Since the core groove 2B has a width and depth of about several tens of μm and is thin, the injected core material is filled by sucking the core material in the length direction of the core groove 2B by capillary action.

  By curing the core material as it is, the cured core 2 is formed in the upper core groove 2B of the lower cladding layer 3. After the core material is cured, the upper clad material is dropped on the core 2 and the lower clad layer 3 by a known method. By curing the dropped upper clad material by a known method, a laminate 6 in which the upper clad layer 5 covering the core 2 is formed on the lower clad layer 3 is obtained.

  A V-groove for the oblique mirror portion corresponding to the oblique mirror portion is formed in a direction in contact with at least one end in the longitudinal direction of the laminated body 6 and orthogonal thereto. The method for forming the V groove is not particularly limited. For example, the V groove 7 can be formed by using a cutting means such as a dicing saw having a V-shaped blade or a laser (FIG. 4A is formed by a dicing saw). 4B is an example of a broad V-groove 7 having a vertex angle of 135 ° formed by a laser). At this time, the angle of the V groove is not particularly limited, and the inclined surface 7A of the oblique mirror portion formed on the core side is 45 ° with respect to the core longitudinal direction, that is, the optical path from the core is changed by 90 ° at the mirror portion. What is necessary is just to form so that it can inject into the light transmission / reception part which is not shown provided in the board | substrate side (other manufacturing examples are also the same).

  As another manufacturing method of the oblique mirror portion, for example, a vertical wall 1W on the end face as shown in FIG. 5 (the vertical wall 1W is orthogonal to the convex portion 2A corresponding to the core groove and extends in the vertical direction). It is also desirable to use the laminate 6 formed through the steps shown in FIGS. 2 and 3 using the first mold 1 ′ having the above. The laminated body 6 formed of the first mold 1 'has an end face 8 perpendicular to the longitudinal direction of the laminated body 6 (core 2) (see FIG. 6). For such a laminated body 6, as shown in FIG. 6, for example, a mirror part material 9 made of an upper clad material or a core material is filled in the vertical end surface 8 of the laminated body 6, and the shape of the oblique mirror part is obtained. Corresponding mold (the angle on the substrate side of the convex slope corresponding to the slope for the oblique mirror part may be 90 ° to 135 °, for example, the apex angle as shown in FIG. The apex angle corresponding to the 1B mold 11A having the V-groove forming convex portion 10A corresponding to the inclined surface of the oblique mirror portion or the inclined surface for the oblique mirror portion as shown in FIG. A 1B mold 11B having a convex portion 10B corresponding to the inclined surface of the oblique mirror portion is pressed against the mirror material 9 to form an inclined surface for the mirror portion, and the mirror material 9 is cured to thereby form an oblique mirror portion. With a slope (45 °) corresponding to A laminated body in which the core 2 and the upper clad layer 5 are laminated on the top of the pad layer 3 is obtained (for example, (a laminated body formed in FIG. 7A is formed in FIGS. 8A and 7B). (See FIG. 8B for the laminated body).

  FIG. 10 is a diagram for explaining an example of a method of using the second mold 12 illustrated in FIGS. 9A and 9B (corresponding to a BB cross-sectional view in FIG. 9B). The general | schematic process of forming an oblique mirror part is shown. In FIG. 10, the metal film 14 is attached to the convex portion 13 that can be in contact with the inclined surface 7A of the broad V-groove (the inclined surface 7A and the 135 ° V groove formed by the substrate 4) of FIG. The second mold 12 is pressed against the core-side inclined surface 7A. At this time, the adhesive 15 is attached to the surface of the core-side slope 7A of the V-groove for the oblique mirror portion of the laminate 6 and / or the surface of the metal film 14 of the convex portion 13 that can contact the slope 7A (illustrated example). Then, an adhesive is attached to the slope 7A). When the metal film 14 of the second mold 12 is pressed against the core-side inclined surface 7A and the metal film 14 is attached to the inclined surface 7A via the adhesive 15, the oblique mirror portion 16 is formed. By releasing the second mold 12, an embedded optical waveguide having an oblique mirror portion 16 and having the core 2 and the upper cladding layer 5 laminated on the lower cladding layer 3 is obtained (optical waveguide). May be peeled off from the substrate 4 as appropriate).

<Method 2 for Producing Optical Waveguide of the Present Invention>
Hereinafter, other production examples of the present invention will be described with reference to the drawings. In FIG. 11, the perspective explanatory drawing of the one end of 1A type | mold 1A was shown. The 1A mold 1A includes a convex portion 2A corresponding to the core groove, and a convex portion corresponding to one end of the core groove corresponding convex portion 2A and corresponding to an oblique mirror portion extending in a direction orthogonal to the core groove corresponding convex portion 2A. 10A. Even at the other end (not shown) of the first mold, the oblique mirror portion corresponding convex portion 10A can be brought into contact with the core groove corresponding convex portion 2A so as to be perpendicular to the core groove corresponding convex portion 2A (or other manufacturing methods). The example is similar).

  The cross-sectional shape of the convex portion 10A corresponding to the oblique mirror portion is an isosceles triangle in the illustrated example. If the mirror part slope is 45 °, that is, the obtuse angle formed by the slope 10B forming the mirror part slope of the 1A mold 1A and the horizontal line in the longitudinal direction of the core groove corresponding convex part 2A is 135 °, The apex angle of the isosceles triangle is not particularly limited, and may be, for example, 90 ° or more, and theoretically less than 180 °.

  Using this 1A mold 1A, a core groove and an oblique mirror V groove are formed in the lower cladding layer. FIG. 12 shows a cross-sectional view taken along the line AA in a state where the 1A mold 1A of FIG. 11 is inverted up and down. The lower clad layer 3A before curing is formed on the substrate 4 by a known method, and as shown in FIG. 12, the 1A mold 1A is turned upside down from FIG. 11 and pressed against the lower clad layer 3A. After releasing the first mold 1A by curing the lower clad layer 3A while pressing the 1A mold 1A, as shown in a perspective view in FIG. The cured lower clad layer 3 having the V-groove 7 is obtained.

  Next, the core material is filled into the core groove 2B by a known method. As a method of filling the groove efficiently and selectively, the core groove 2B has a width and depth of about several tens of μm and is thin. Therefore, a core material is dropped on a predetermined location of the core groove 2B, and capillary action occurs. A method of filling the core material in the length direction of the core groove 2B is preferable. By setting the depth of the core groove 2B to be shallower than the depth of the apex portion of the V-groove 7 of the oblique mirror portion and setting the dropping position of the core material to the inside of the length of the core groove from the V-groove 7 of the mirror portion, The core material can be selectively filled only in the core groove 2B. This is because the capillary action is stopped by the interfacial tension between the core material and air at the intersecting surface of the core groove 2B and the oblique surface of the V groove 7. In order to increase the filling rate into the core groove, the fluidity of the core material may be improved by heating the substrate, the lower cladding layer, or the core material. For example, when the substrate is heated in the range of 50 ° C. or more and 200 ° C. or less, heat is transmitted to the core material through the lower cladding layer, and the core material is heated. If the temperature is too low, there is no significant improvement in the filling rate. On the other hand, if the temperature is too high, the core material begins to cure by heat and cannot be filled.

  Thereafter, the core material is cured to form the core 2. After the core material is cured, the upper clad material 5A is applied onto the core 2 and the lower clad layer 3, and then the upper clad material 5A filled in the V-groove is removed using the mold 1B. This is because when the upper clad material is applied on the core or the lower clad layer, the upper clad material may flow into the V groove and be filled.

  FIG. 14 is an explanatory diagram using the 1B mold 11A shown in FIG. In FIG. 14, before the upper clad material 5 </ b> A applied to the upper portion of the lower clad layer 3, the core 2, and the V-groove 7 is cured, the 1B mold 11 </ b> A is pressed against the lower clad layer 3. The upper cladding material 5A filled in the V-groove 7 is pushed out by the oblique mirror portion corresponding convex portion 10A of the 1B mold 11A and removed from the V-groove. By curing the upper cladding material 5A as it is, the cured upper cladding layer 5 is formed on the lower cladding layer 3 and the core 2. By releasing the first B mold 11A, a laminated body having the V-groove 7 and the core 2 and the upper clad layer 5 laminated on the lower clad layer 3 is obtained.

  Next, an oblique mirror part is made of a metal film. FIG. 15 is a diagram (an BB cross-sectional view of FIG. 9A) for explaining an example of the usage method of the second mold, and shows a schematic process of forming the oblique mirror portion. In FIG. 15, a second mold 12 having a convex portion 13 that can come into contact with the core-side inclined surface 7 </ b> A of the V-groove for the oblique mirror portion of the laminated body obtained by curing the upper cladding material is used. A metal film is attached to the convex portion 13 of the second mold 12.

  In addition, an adhesive 15 is attached to the inclined surface 7A of the V-groove for the oblique mirror portion and / or the surface of the metal film 14 of the second mold 12 (the adhesive 15 is attached to the surface of the metal film 14 in the illustrated example). ). The metal film 14 is attached to the V-groove inclined surface 7A through the adhesive 15 to form an oblique mirror portion. That is, when the convex portion 13 of the second mold 12 is pressed against the core-side inclined surface 7A of the V-groove, the adhesive 15 adheres to the inclined surface 7A of the V-groove, and the metal film 14 is inclined via the adhesive 15 An embedded structure type optical waveguide attached to 7A and having a mirror portion is obtained (the optical waveguide may be used by appropriately peeling from the substrate).

<Method 3 for Producing Optical Waveguide of the Present Invention>
Hereinafter, another example of a method for manufacturing an optical waveguide using the second mold of the present invention will be described.

  First, in the same manner as in the optical waveguide manufacturing method 2, the core 2 is formed on the upper portion of the lower cladding layer 3 having the V-groove.

  That is, the convex portion 2A corresponding to the core groove shown in FIG. 11 and the convex portion 10A corresponding to the oblique mirror portion that is in contact with one end of the core groove corresponding convex portion 2A and extends in a direction orthogonal to the core groove corresponding convex portion 2A. 12A and 12B, the core groove 2 and the oblique mirror portion V-groove 7 are formed in the lower cladding layer 3 as shown in FIG. Next, if the core material is injected and filled in the core groove 2B and the core material in the core groove 2B is hardened, the core 2 is formed on the upper portion of the lower clad layer 3 with the V groove.

  Next, the upper clad material is applied on the inclined surface of the oblique groove V groove, the core, and the lower clad layer. Subsequently, before the upper clad material is cured, the oblique mirror portion is made of a metal film. This will be specifically described with reference to FIG. FIG. 16 is a diagram for explaining an example of the usage method of the second mold (BB sectional view of FIG. 9A), and is a schematic process for forming an oblique mirror portion (lower cladding layer 3 of FIG. 13). Is a state viewed from the cross-sectional direction along line B-B). In FIG. 16, the upper clad material 5 </ b> A is applied on the core side inclined surface 7 </ b> A, the core 2, and the lower clad layer 3 of the mirror part V groove 7 of the laminated body in which the core material is cured by a known method. Before the applied upper clad material 5A is cured, the second groove | channel which has the convex part 13 which can contact | abut to the core side inclined surface 7A of V groove | channel, and has the metal film 14 in this convex part 13 is made into V groove | channel 7. Pressing (preferably pressing so that the core-side slope 7A of the V-groove and the core-side slope of the convex portion 13 face each other). The convex metal film 14 corresponding to the second type of oblique mirror portion is transferred to the surface of the upper clad material 5A of the V-groove to form a mirror portion.

  After forming the oblique mirror portion, the upper clad material 5A is hardened by a known method to form the upper clad layer 5 covering the core 2 on the lower clad layer 3. By releasing the second mold 12, an optical waveguide having a buried structure having a mirror part formed of the metal film 14 and having the core 2 and the upper clad layer 5 laminated on the lower clad layer 3 is obtained. can get.

<Production method 4 of the present invention>
Furthermore, another example of the optical waveguide manufacturing method 3 using the second mold of the present invention will be described.

  First, similarly to the manufacturing method 3 described above, the steps until the core groove, the oblique mirror portion V-groove and the lower cladding layer are formed using the second mold as shown in FIG. 11 are the same (FIG. 12, FIG. 13).

  Next, the core material is filled into the core groove 2B and the oblique mirror portion V-groove 7 by a known method. At this time, if the width and depth of the core groove 2B are thin and shallow as described above, the core material is sucked in the length direction of the core groove 7 by capillary action. Filled.

  Therefore, in order to remove the core material filled from the V-groove 7, the 1B mold is used. As shown in FIGS. 7 (A) and 7 (B), the 1B mold has the convex portions corresponding to the oblique mirror portion having the same shape as the 1A mold shown in FIG. Does not have.

  The method of using the type 1B is almost the same as the process shown in FIG. 14, and will be described with reference to FIG. 14. The core material 17 filled in the core groove 2B of the lower cladding layer 3 and the V groove 7 are filled. Before the core material 17A is cured, the 1B mold 11A is pressed against the lower cladding layer 3. The core material 17A filled in the V-groove is pushed out by the oblique mirror portion corresponding convex portion 10A of the 1B mold 11A and removed from the V-groove, but the core material 17 filled in the core groove 2B is Since the core material 17 is cured as it is, the core 2 cured in the core groove 2B is formed on the upper portion of the lower clad layer 3 because it is not removed. The core 2 is formed on the upper portion of the lower cladding layer 3 by having the V-groove 7 by releasing the first-B mold 11A.

  Thereafter, in the same manner as in the above manufacturing method 3, according to the process shown in FIG. 16, the upper cladding material 5A is applied onto the slope 7A, the core 2 and the lower cladding layer 3 of the V-groove 7 for the oblique mirror portion, If the second mold 12 having the metal film 14 on the part 13 is pressed against the upper clad material 5A, the second mold 12 has a mirror part formed of the metal film 14 and the core 2 and the upper part of the lower clad layer 3. An optical waveguide having a buried structure in which the upper cladding layer 5 is laminated is obtained.

  Hereinafter, the formation of the mirror part using the second mold will be described in more detail.

  First, the metal film that forms the oblique mirror portion will be described in detail. The oblique mirror portion needs to be formed on the core-side inclined surface 7A in contact with the core 2 of the V groove 7. Examples of the metal film that can be used for forming the oblique mirror portion include Au, Ag, Cu, Al, and the like, or an alloy containing one or more of these, and the wavelength of light to be used (for example, 700 when used for communication). A metal film having a high reflectance at a wavelength of ˜1600 nm, particularly a wavelength of 800 to 900 nm is preferable, and a metal film having a reflectance of 70% or more is more preferable. Examples of the metal film having high reflectivity and excellent chemical stability include Au and Ag. From the viewpoint of cost reduction, Al or Cu is preferable. In the present invention, in order to easily form an oblique mirror portion, it is preferable to form an oblique mirror portion of a metal film using a metal foil. From the viewpoint of increasing the reflectance, the surface of the metal foil is mirror-finished. It is more preferable.

  The thickness of the metal foil used in the present invention is not particularly limited. However, if the film thickness is too thin, wrinkles and breakage are likely to occur, and light is transmitted through the film and the reflectance is reduced. More preferably, the thickness is 5 μm or more. On the other hand, if the thickness of the metal foil is too thick, the metal foil is inclined at the corner formed by the slope of the oblique mirror portion and the slope of the lower cladding layer (for example, the apex angle formed by the slope of the V groove in FIG. 8). Since R may be formed without following, the thickness of the metal foil is preferably thinner than the thickness of the lower cladding layer, for example, preferably 25 μm or less, and more preferably 10 μm or less. When R is formed, the metal film may be broken or wrinkles are generated and propagated from the R portion, which may cause a decrease in reflectance.

  Moreover, it is desirable to appropriately control the surface roughness of the metal foil from the viewpoint of suppressing the decrease in reflectance. If the surface of the metal foil is rough, light loss occurs due to irregular reflection of light. Therefore, the surface roughness of the metal foil (arithmetic average roughness Ra defined in JIS B0601 2001) is preferably 0.3 μm or less, more preferably 0.1 μm. It is as follows.

  Next, the shape of the 2nd type | mold should just have the convex part which can contact | abut to the core side slope of the V groove | channel for diagonal mirror parts. The abutable convex portion means that the shape of the other portion may be different if the shape of the convex portion of the second mold and the shape of the V groove coincide with each other on the slope on the core side. This is because the oblique mirror portion of the optical waveguide functions if a metal film is formed on the core-side slope of the V-groove. Therefore, as shown in FIG. 9A, the shape of the convex portion 13 of the second mold 12 may be a shape that fits into the shape of the V groove 7, but FIG. 17B and FIG. It is also possible to use a second mold having a shape that only matches the core-side slope 7A of the V-groove 7 as shown in C).

  Next, means for attaching the metal film to the convex portion of the second mold will be described. In the present invention, the means for attaching the metal film is not particularly limited as long as the second mold having the metal film is pressed against the slope of the V-groove so that the metal film can be transferred or pasted from the second mold to the V-groove side. .

  For example, the metal film can be adsorbed on the convex part of the second mold. FIG. 18 is a perspective view for explaining an example of a second mold having a suction mechanism. In FIG. 18, a suction mechanism in which a plurality of slits 70 are provided at arbitrary positions in the second mold is formed. After the metal film is placed on the convex portion, air is sucked from the intake port 71 to bring the inside of the slit (a space formed by the slit and a metal film not shown) into a negative pressure state, so that the metal film Adsorbed to the mold. Then, after the second mold is pressed into the V-groove, if the suction is stopped, the metal film is transferred or pasted from the second mold to the V-groove side.

  The metal film can also be self-attached to the second mold. If at least the convex part corresponding to the mirror part of the second mold is made of a resin material or a silicone material, the pseudo-adhesive property of the silicone material etc. (adhesion by self-adhesion, the adhesion part is a small force, and the adhesion surface is destroyed. The metal film can be self-attached by an adhesive state that can be peeled off without being carried out. When the second mold is pressed against the V-groove, the metal film is transferred or pasted to the V-groove side by an upper clad material or adhesive having strong adhesiveness.

  Further, the metal film can be attached to the second mold via a pressure-sensitive adhesive or an adhesive (hereinafter referred to as an adhesive). Examples of the adhesive include a UV peelable adhesive and a heat peelable adhesive. In this case, after pressing the second mold with the metal film attached to the V-groove, the metal film is formed by applying a peeling means such as ultraviolet irradiation (UV peeling adhesive) or heating (thermal isolation adhesive). It peels from the second mold and is transferred or pasted on the V-groove side.

  The metal film does not have to be attached to the entire surface of the second mold convex portion, and may be attached at least at the light reflecting portion of the core-side slope contact surface. This is because if the metal film is formed on the core side slope, the optical path conversion function can be exhibited.

  According to the said manufacturing method, the optical waveguide by which the diagonal mirror part was formed in the metal film (preferably metal foil) in the at least one end of the core can be manufactured.

  In the optical waveguide of the present invention, since the metal film is formed on the inclined surface for the oblique mirror portion through the upper clad material or the adhesive, for example, when the inclined surface is formed by a cutting means such as a dicer. Even if the surface is rough due to fine irregularities on the slope surface, the step of the fine irregularities is flattened by covering with the upper clad material or adhesive, which affects the surface roughness of the mirror part There is no.

<Preferred examples of various materials used in the method of the present invention>
[First mold, 1A mold, 1B mold, and 2nd mold]
The material of the first mold, the first A mold, the first B mold, and the second mold is not particularly limited, and may be a mold made of an alloy such as phosphor bronze or another metal such as nickel, A mold made of a soft material such as a silicone material or a urethane resin may be used. A silicone material is particularly preferable from the viewpoint of releasability from the clad material and the core material. Among the silicone materials, curable silicone rubber oligomers or monomers that become silicone rubbers or silicone resins after curing, or curable silicone materials such as curable silicone resin oligomers or monomers are suitable, and curable polysiloxanes. Is particularly preferred.

  As the curable silicone material, what is called liquid silicone is usually used, but since it is excellent in peelability from the formed lower clad layer and excellent in mechanical strength, it is used in combination with a curing agent. A liquid mixed type is preferred. If a low-viscosity curable silicone material is used, it is excellent in workability such as removal of bubbles entrained during the production of the mold, and a precise pattern of the transfer pattern can be obtained. On the other hand, the curable polysiloxane may be either a one-component curable type or a two-component curable type, and may be either a thermosetting type or a room temperature curable type.

  Specific examples of the curable silicone material include those containing alkyl siloxane, alkenyl siloxane, alkyl alkenyl siloxane, polyalkyl hydrogen siloxane and the like. In particular, a two-component mixed system of an alkyl alkenyl siloxane and a polyalkyl hydrogen siloxane, which has a low viscosity and is room temperature curable, is preferable from the viewpoint of peelability and curability.

  It is desirable to apply and use a release agent so that the lower cladding layer and the core are easily released from the first mold, the first A mold, the first mold B, and the second mold. A known release agent may be used as the release agent, and is not particularly limited.

[Second type]
Furthermore, in addition to the above materials, glass materials such as quartz and Pyrex (registered trademark) can be used in the second mold, but a suitable material can be selected depending on the means for attaching the metal film to the second mold. It is desirable to choose. For example, when an adsorption mechanism as shown in FIG. 18 is provided in the second mold, an alloy such as phosphor bronze, another metal such as nickel, or a glass material is preferable from the viewpoint of workability.

  When the metal film is self-attached to the second mold, a silicone material or a resin material having pseudo-adhesiveness is suitable, but a hard material is particularly desirable. This is because if the second mold is formed of a soft material, the second mold may be deformed and the inclination angle of the core-side inclined surface may fluctuate when contacting the V groove.

  Further, when the metal foil is attached to the second mold via the UV peeling type pressure-sensitive adhesive, a glass material having transparency and a transparent resin material are suitable. Moreover, when attaching metal foil to a 2nd type | mold through a heat | fever exfoliation-type adhesive, the heat-resistant metal material, glass material, etc. are suitable.

[substrate]
Although the substrate is omitted in the above example, it is an essential component in the optical waveguide. Any known material can be used as the substrate regardless of whether it is an inorganic material or an organic material. For example, a silicone substrate; a glass substrate such as quartz or Pyrex (registered trademark); a metal substrate such as Al or Cu. A metal oxide substrate; a resin substrate such as polyimide or polyetherketone; an organic-inorganic hybrid substrate or the like is preferably used. When producing a flexible optical waveguide, a resin substrate is preferable, and a film substrate made of a resin film is more preferable.

  The film substrate is not particularly limited as long as it is a resin film composed of a conventionally known optical waveguide material. Specifically, an epoxy resin, a polyimide resin, an acrylic resin, and a polyester resin are used. Examples include resin films composed of resins, polystyrene resins, cycloolefin resins, polyether sulfone resins, polyether ketone resins, polyether nitrile resins, oxetane resins, silane resins, silicone resins, and the like. . Among these resin films, considering the production of the opto-electric hybrid board, from the viewpoint of heat resistance (particularly heat resistance assuming soldering, specifically 200-250 ° C. heat resistance), a polyimide resin That is, a film composed of a polyimide film (including a halogenated polyimide film) is preferable. Moreover, when using a polyimide film as a film substrate, you may utilize a commercial item. As a commercial item of a polyimide film, the brand name "Kapton (trademark)" series of Toray DuPont Co., Ltd. is mentioned, for example.

  The thickness of the substrate may be appropriately selected according to the use of the optical waveguide, the wavelength of light used when the opto-electric hybrid flexible substrate is manufactured, and is not particularly limited, but is preferably 5 μm or more. More preferably, it is 10 μm or more, preferably 100 μm or less, more preferably 50 μm or less. If the thickness of the substrate is too small, the strength of the substrate may be reduced, or wrinkles or creases may occur during production. On the other hand, if the thickness of the substrate is too large, the transparency of the substrate may decrease when an opto-electric hybrid board is manufactured.

[Lower cladding layer]
The clad material constituting the lower clad layer is not particularly limited as long as it is a conventionally known optical waveguide material. For example, a curable resin such as an ultraviolet (or light) curable resin or a thermosetting resin is used. And thermoplastic resins. Of these resins, ultraviolet (or light) curable resins are preferred. Specific examples of the curable resin and the thermoplastic resin include, for example, an epoxy resin, a polyimide resin, an acrylic resin, a polystyrene resin, a cycloolefin resin, a polyether sulfone resin, a polyether ketone resin, and a polyether. Examples include nitrile resins, oxetane resins, silane resins, silicone resins, and the like. These resins may be used alone or in combination of two or more. These resins may be a solution type dissolved in a solvent or a solventless type containing no solvent, but a solventless type is more preferable. Furthermore, when these resins are used as the curable resin, a curing agent, a crosslinking agent, or the like can be used in combination.

  Among the curable resins, epoxy resins are preferable, and UV curable epoxy resins are more preferable. Examples of the UV curable epoxy resin include a UV curable epoxy resin, a bisphenol type epoxy resin, and an alicyclic epoxy resin containing a polyglycidyl compound having a polyalkylene glycol chain and at least two glycidyl groups. In order to obtain a flexible optical waveguide having flexibility, a UV curable epoxy resin containing a polyglycidyl compound having a polyalkylene glycol chain and at least two glycidyl groups is particularly suitable. When it is not necessary to give flexibility, a bisphenol type epoxy resin, an alicyclic epoxy resin, or the like is preferable.

  As the polyglycidyl compound having a polyalkylene glycol chain and at least two glycidyl groups, diglycidyl ether of polytetramethylene ether glycol is particularly suitable. Examples of commercially available diglycidyl ether of polytetramethylene ether glycol include trade names “jER (registered trademark) YL7410” and “jER (registered trademark) YL7217” manufactured by Japan Epoxy Resin Co., Ltd.

  When using a UV curable epoxy resin containing the polyglycidyl compound, a reactive diluent such as a bisphenol type epoxy resin, an alicyclic epoxy resin, or oxetane is used as necessary to adjust the refractive index and viscosity. You may mix | blend. However, an epoxy resin having a lower viscosity is preferable because it is excellent in handleability.

  Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, diglycidyl ether of bisphenol A-alkylene oxide adduct, bisphenol F type epoxy resin, diglycidyl ether of bisphenol F alkylene oxide adduct, and bisphenol AD type epoxy resin. Bisphenol S type epoxy resin, tetramethyl bisphenol A type epoxy resin, tetramethyl bisphenol F type epoxy resin, halogenated bisphenol type epoxy resin (for example, fluorinated bisphenol type epoxy resin, chlorinated bisphenol type epoxy resin, brominated Bisphenol type epoxy resin). These bisphenol type epoxy resins may be used alone or in combination of two or more. Of these bisphenol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, brominated bisphenol A-type epoxy resins, and brominated bisphenol F-type epoxy resins are preferred from the viewpoint of easy availability and handling. . As commercial products of these bisphenol type epoxy resins, for example, trade names “jER (registered trademark) 828EL” (bisphenol A type epoxy resin) and “jER (registered trademark) 5050” (brominated bisphenol) manufactured by Japan Epoxy Resin Co., Ltd. A-type epoxy resin).

  The blending amount of the bisphenol type epoxy resin may be appropriately adjusted so that the epoxy resin film obtained from the UV curable epoxy resin has a desired refractive index, and is not particularly limited. When the total of the removed UV curable epoxy resin composition is 100% by mass, the blending amount of the polyglycidyl compound, the bisphenol type epoxy resin, and the alicyclic epoxy resin is 0% by mass to 70% by mass of the polyglycidyl compound. The total of the mass% (more preferably 5 mass% to 60 mass%) and the bisphenol type epoxy resin and the alicyclic epoxy resin is 30 mass% to 100 mass% (more preferably 40 mass% to 95 mass%). Is preferred. When the compounding quantity of a polyglycidyl compound exceeds 70 mass%, the cure rate of a film may become slow or the intensity | strength of the obtained film may be insufficient. Moreover, if the addition amount of a polyglycidyl compound is 5 mass% or more, the film provided with intensity | strength and flexibility can be obtained.

  Examples of the alicyclic epoxy resin include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate and its ε-caprolactone modified product (trade name “Celoxide (registered trademark)” manufactured by Daicel Chemical Industries, Ltd. 2081 "), 1,2-epoxy-vinylcyclohexene, bis (3,4-epoxycyclohexylmethyl) adipate, 1-epoxyethyl-3,4-epoxycyclohexane, limonene diepoxide, 3,4-epoxycyclohexylmethanol, di Cyclopentadiene diepoxide, oligomer type alicyclic epoxy resin (manufactured by Daicel Chemical Industries, trade name “Epolide (registered trademark) GT300”, “Epolide (registered trademark) GT400”, “EHPE (registered trademark) 3150”), etc. Oxidize olefins Epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated biphenol type epoxy resin, hydrogenated phenol novolac type epoxy resin, hydrogenated cresol novolac type epoxy resin, hydrogenated naphthalene type Examples thereof include an epoxy resin obtained by directly hydrogenating an aromatic epoxy such as an epoxy resin or an epoxy resin obtained by hydrogenating a polyhydric phenol and then reacting with epichlorohydrin. These alicyclic epoxy resins may be used alone or in combination of two or more. Among these alicyclic epoxy resins, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate and its ε-caprolactone modified product, since it is easily available and has low viscosity and excellent workability. Hydrogenated bisphenol A type epoxy resins and hydrogenated bisphenol F type epoxy resins are preferred.

  The compounding quantity of an alicyclic epoxy resin is not specifically limited, What is necessary is just to adjust suitably so that UV curable epoxy resin may have a desired refractive index.

  In order to photocur the UV curable epoxy resin, it is preferable to add a cationic photopolymerization initiator.

  Examples of the cationic photopolymerization initiator include metal fluoroboron complex salts, boron trifluoride complex compounds, bis (perfluoroalkylsulfonyl) methane metal salts, aryldiazonium compounds, aromatic onium salts of group VIa elements, group Va elements Aromatic onium salts IIIa-Va elements dicarbonyl chelates, thiopyrylium salts, MF6-anions (where M is selected from phosphorus, antimony and arsenic) in the form of VIb elements, arylsulfonium complexes, aromatic Iodonium complex salt, aromatic sulfonium complex salt, bis [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluorometal salt (for example, phosphate, arsenate, antimonate, etc.), mixed arrangement of iron compound A ligand metal salt, a silanol-aluminum complex, etc. are mentioned. These photocationic polymerization initiators may be used alone or in combination of two or more. Of these photocationic polymerization initiators, arylsulfonium complex salts, aromatic iodonium complex salts of halogen-containing complex ions or aromatic sulfonium complex salts, and aromatic onium salts of Group II, Group V and Group VI elements are preferred. Some of these salts are, for example, trade names “AT-6976”, “AT-6990” (manufactured by Aceto Chemical), trade names “FX-512” (manufactured by 3M Company), trade names “UVR”. -6990 "," UVR-6974 "(manufactured by Union Carbide Corporation), trade names" UVE-1014 "," UVE-1016 "(manufactured by General Electric Company), trade names" KI-85 ". "(Degussa Aktiengesellschaft), trade names" SP-150 "," SP-170 "(above, manufactured by ADEKA Corporation), trade names" Sun-Aid (registered trademark) SI-60L "," Sun-Aid (registered trademark) ) SI-80L "," Sun-Aid (registered trademark) SI-100L "," Sun-Aid (registered trademark) SI-110L " ”,“ Sun-Aid (registered trademark) SI-180L ”(manufactured by Sanshin Chemical Industry Co., Ltd.) can be obtained.

  Of these photocationic polymerization initiators, onium salts are preferred because of their excellent handleability and balance between latency and curability, and diazonium salts, iodonium salts, sulfonium salts, and phosphonium salts are particularly preferred. Is preferred.

  The blending amount of the cationic photopolymerization initiator may be appropriately adjusted according to the blending amount of the epoxy resin component to be cured, and is not particularly limited, but is preferably based on 100 parts by mass of the total epoxy resin component. Is 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, further preferably 1 part by mass or more, preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and further preferably 5 parts by mass. Or less.

  The UV curable epoxy resin has an appropriate molecular weight such as a polyglycidyl compound having a polyalkylene glycol chain and at least two glycidyl groups as raw materials, and a bisphenol type epoxy resin or an alicyclic epoxy resin blended as necessary. By selecting, the viscosity can be adjusted within a range of 10 mPa · s or more and 100,000 mPa · s or less at a temperature of 23 ° C. without using a solvent.

Since the UV curable epoxy resin is liquid at room temperature, a container or mold for the lower cladding layer is appropriately placed on the substrate, and an appropriate amount is injected into the gap to fill it, or on the substrate. After dropping the appropriate amount onto the first mold, after placing the first mold, for example, by irradiating with ultraviolet rays having an irradiation integrated light quantity (exposure energy) of about 0.01 J / cm ^{2 to} 10 J / cm ² , A clad layer can be formed.

  The thickness of the lower cladding layer may be appropriately selected according to the use of the optical waveguide, the wavelength of light to be used, and the like, and is not particularly limited, but is preferably 10 μm or more except for the lower side of the core groove. More preferably, it is 20 μm or more, preferably 150 μm or less, more preferably 100 μm or less. If the thickness of the lower cladding layer is too small, a sufficiently thick core may not be formed. Conversely, if the thickness of the lower clad layer is too large, the transparency of the lower clad layer may be reduced when an opto-electric hybrid board is manufactured.

  The refractive index of the lower cladding layer is not particularly limited as long as it is lower than the refractive index of the core. For example, by selecting the type and composition of the cladding material within the range of 1.45 to 1.65. Can be adjusted arbitrarily.

[core]
Examples of the core material for forming the core include materials that can be used for the lower cladding layer. However, it is necessary to select materials so that the lower cladding layer or the upper cladding layer and the core have different refractive indexes. The thickness (depth) of the core may be appropriately selected according to the use of the optical waveguide, the wavelength of light to be used, and the like, and is not particularly limited, but is preferably 5 μm or more, more preferably 10 μm or more. In addition, it is preferably 100 μm or less, more preferably 50 μm or less. If the thickness of the core is too small, the amount of light propagating through the core may be reduced. On the other hand, if the thickness of the core is too large, it is necessary to increase the thickness of the lower cladding layer, and unnecessary portions of the lower cladding layer increase on both sides of the core, which may increase the manufacturing cost. Further, since the thickness of the lower cladding layer and the core constituting the optical waveguide is increased, the thickness of the optical waveguide film may be increased.

  The core preferably has a rectangular cross section perpendicular to the longitudinal direction, and most preferably has a square shape. The aspect ratio (width / thickness) of the core is preferably ½ or more, more preferably 2/3 or more, still more preferably 5/6 or more, and preferably 2/1 or less, more preferably 3 / 2 or less, more preferably 6/5 or less. Most preferably, it is 1/1. If the aspect ratio of the core is too small or too large, the shape of the cross section perpendicular to the longitudinal direction of the core will become flat, so when light enters or exits the core Optical loss may occur.

  The refractive index of the core is not particularly limited as long as it is higher than the refractive indexes of the lower cladding layer and the upper cladding layer. For example, the refractive index of the core is preferably in the range of 1.45 to 1.65. It can be arbitrarily adjusted by selecting the type and composition.

[Upper clad layer]
Examples of the material for forming the upper clad layer include the materials that can be used for the lower clad layer. However, it is necessary to select a material so that the refractive index is different from that of the core.

  The thickness of the upper cladding layer from the upper end surface of the core to the upper end surface of the upper cladding layer may be appropriately selected according to the use of the optical waveguide, the wavelength of light to be used, etc., but is not particularly limited, but preferably It is 10 μm or more, more preferably 20 μm or more, and preferably 100 μm or less, more preferably 50 μm or less. If the thickness of the upper cladding layer is too small, the light confinement effect in the core is weakened, and light may escape from the upper cladding layer, which may increase optical loss. On the other hand, if the thickness of the upper clad layer is too large, unnecessary portions increase and the manufacturing cost may increase.

  The refractive index of the upper cladding layer is not particularly limited as long as it is smaller than the refractive index of the core, but is preferably within the range of 1.45 to 1.65, for example, and the type and composition of the cladding material By selecting, it can be arbitrarily adjusted.

[Second type pressure-sensitive adhesive or adhesive]
As a pressure-sensitive adhesive or adhesive used when a metal film (metal foil) is attached to the second mold via a pressure-sensitive adhesive or adhesive (represented by a pressure-sensitive adhesive), the metal film from the second mold is used. Although it will not specifically limit if it can peel easily, For example, an ultraviolet-ray (or light) peelable adhesive, a heat peelable adhesive, etc. are mentioned. These pressure-sensitive adhesives can be arbitrarily selected and used. There is no particular limitation on the amount used, and an appropriate amount necessary for attaching the metal foil to the second mold may be used.

[Adhesive for oblique mirror part of V groove]
The adhesive to be attached to the slope of the V-groove for the oblique mirror portion and / or the surface of the metal film of the second mold convex portion is not particularly limited as long as it has translucency. Examples thereof include an ultraviolet curable epoxy resin, an ultraviolet curable acrylic resin, a thermosetting epoxy resin, and a thermosetting acrylic resin. Among these, a thermosetting epoxy resin is preferable. Although the thickness of an adhesive bond layer is not specifically limited, Preferably it is 1 micrometer or more, Preferably it is 5 micrometers or less, More preferably, it is 3 micrometers or less. If the thickness of the adhesive layer is too small, the metal film cannot be sufficiently adhered, and the metal film may peel from the optical waveguide. On the other hand, if the thickness of the adhesive layer is too large, the light transmission property may deteriorate, or the light reflection position may shift and the performance of the opto-electric hybrid board may deteriorate.

  As described above, the present invention is characterized in that the second mold having the above configuration is employed in order to form the metal film on the slope on the core side of the V groove for the oblique mirror portion. For this reason, materials and structures such as electric circuits other than these characteristics are not particularly limited, and any conventionally known materials and structures of opto-electric hybrid boards can be employed. It is also possible to use a flexible opto-electric hybrid board using a film substrate. Further, the manufacturing method of the opto-electric hybrid board is not particularly limited, and a known method can be adopted.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

  First, a method for preparing a UV curable epoxy resin used as a clad material and a core material in Examples and Comparative Examples will be described.

<Preparation of UV curable epoxy resin (1)>
Polytetramethylene glycol diglycidyl ether (manufactured by Japan Epoxy Resin; trade name “jER (registered trademark) YL7410”; number average molecular weight 700-800) 48 parts by mass, ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3 30 parts by mass of ', 4'-epoxycyclohexanecarboxylate (manufactured by Daicel Chemical Industries, Ltd .; trade name “Celoxide (registered trademark) 2081”), bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin Co., Ltd .; trade name “jER (registered trademark)) ) 828EL ") 18 parts by mass, 4 parts by mass of triarylsulfonium hexafluorophosphate (manufactured by Aceto Chemical; product name" AT-6992 ") which is a photopolymerization initiator, , Product name "Awatori Nerita (registered) Trademark) ") were mixed was used to prepare UV-curable epoxy resin (1) used as a cladding material.

<Preparation of UV curable epoxy resin (2)>
9 parts by mass of diglycidyl ether of polytetramethylene glycol ("jER (registered trademark) YL7410") used above, 43.5 parts by mass of the bisphenol A type epoxy resin ("jER (registered trademark) 828EL") used above , 43.5 parts by mass of brominated bisphenol A type epoxy resin (manufactured by Japan Epoxy Resin; trade name “jER (registered trademark) 5050”), 4 parts by mass of the photopolymerization initiator (“AT-6992”) used above Were mixed using the rotation / revolution mixer used above to prepare a UV curable epoxy resin (2) used as a core material.

Example 1
First, in order to produce the 1A mold 1A (FIG. 11) and the 1B mold 11A (FIG. 7A) of the present invention, two female molds were produced. The surface of the phosphor bronze plate is cut, the core groove-corresponding recess having a width of 50 μm, the depth of 50 μm, and the length of 50 mm corresponding to the core groove, and the core groove-corresponding recess, and extending in a direction perpendicular to the core-groove corresponding recess A recess corresponding to a V groove having a depth of 75 μm (vertical angle = 90 °) was formed, and a phosphor bronze mold A having the same shape as the lower cladding layer 3 shown in FIG. 13 was produced. This type A is a type for the 1A type 1A. In addition, the surface of another phosphor bronze plate was cut to produce a mold B in which only a concave portion corresponding to a V groove (vertical angle = 90 °) having a depth of 75 μm was formed. This mold B is a mold for the 1B mold 11A. The surface roughness Ra of the convex portion 10A corresponding to the V-groove of the 1A mold 1A was 400 mm.

  On the glass substrate (thickness: 2 mm), the phosphor bronze mold A was placed upside down with a gap between them, and without interposing bubbles in the gap between the glass substrate and the phosphor bronze mold, A two-part curable silicone rubber (trade name “SILPOT 184” manufactured by Toray Dow Corning Co., Ltd.) is injected and filled, and left to stand at room temperature for 24 hours to be cured. A mold 1A was produced. In the same manner as described above, a 1B mold 11A made of silicone rubber was produced.

  In order to create the second mold of the present invention (FIG. 18), the surface of the quartz substrate is cut, and the height of the convex portion corresponding to the convex portion (height from the apex angle to 12) is 100 μm and the width is 10 mm. A mirror is formed, and as shown in the figure, four suction slits 70 (width 0.5 mm, depth 0.5 mm) are arranged at a pitch 2.5 mm in the width direction and two on both sides of the convex portion. A book was formed, and two inlets 71 were formed to produce a second mold made of quartz.

After a suitable amount of UV curable epoxy resin (1) is dropped as a clad material on a polyimide film (trade name “Kapton (registered trademark) H type” manufactured by Toray DuPont Co., Ltd .; thickness 25 μm) as a film substrate On the stage with parallelism, as shown in FIG. 12, the 1A mold 1A was pressed against the lower clad layer 3A before curing. Next, UV irradiation was performed from the 1A mold 1A side to cure the clad material, and then the 1A mold 1A was peeled off. A cured lower cladding layer 3 having a V-groove 7 and a core groove 2B was formed on the film substrate. UV irradiation is performed using an exposure machine (trade name “MA-60F” manufactured by Mikasa Co., Ltd.) using a high-pressure mercury lamp as a light source at an illuminance of 10 mW / cm ² for 15 minutes, that is, under an exposure energy of 9 J / cm ² . went.

  Subsequently, an appropriate amount of UV curable epoxy resin (2) is dropped on the V groove 7 and the core groove 2B of the lower clad layer 3 and is heated on a hot plate at 150 ° C. while utilizing a capillary phenomenon to form the V groove 7. The core material was filled in the entire core groove 2B. As shown in FIG. 14, the core material 17A was filled in the V groove of the lower cladding layer, and the core material 17 was filled in the core groove. Next, alignment is performed so that the V-groove corresponding convex portion 10A of the first B mold 11A contacts the V groove 7 of the lower cladding layer 3, and the vertex of the V groove corresponding convex portion 10A of the first B mold 11A is The 1B mold 11A is pressed against the lower cladding layer 3 so as to contact the apex (deepest part) of the V-groove 7 of the lower cladding layer 3, and the core material 17A in the V-groove 7 is exposed from the V-groove 7 to the outside. Extruded and eliminated. Subsequently, UV irradiation was performed from the 1B mold 11A side under the same conditions as described above, and the core material 17 inside the core groove 2B was cured to form the core 2. The core 2 has a slope with an inclination angle of 45 ° on one end face.

  Next, a metal film (gold foil: thickness 1 μm, size 2 × 10 mm) is placed on the V-groove corresponding convex portion 13 of the second mold 12 made of glass having the suction mechanism shown in FIG. The air was always sucked in to make the space formed by the gold foil and the slit a negative pressure, and the metal foil was adsorbed to the convex portion 13.

  Subsequently, a metal film was formed by the process shown in FIG. That is, on the laminate of the core and the lower clad layer obtained above and on the slope of the V groove, the UV clad epoxy resin (1) as the upper clad material 5A is formed with a spin coater so that the film thickness becomes 20 μm. Applied. Next, it was pressed so that the metal film of the convex part 13 of the 2nd type | mold 12 might contact | abut to UV hardening type epoxy resin (1) formed in the core side inclined surface 7A of the V groove | channel 7 for mirror parts. At this time, alignment is performed, and the second die 12 is placed on the lower side so that the vertex of the V-groove corresponding convex portion 13 of the second die 12 is in contact with the vertex (the deepest portion) of the V-groove 7 of the lower cladding layer 3. After pressing against the clad layer 3, the suction from the suction portion was stopped, and the gold foil was transferred onto the surface of the upper clad material 5 </ b> A on the core-side slope 7 </ b> A of the V groove 7. Subsequently, UV irradiation is performed from the second mold 12 side under the same conditions as described above to cure the upper clad material 5A to form the upper clad layer 5, and the mirror portion of the metal film 14 on the core side slope of the V groove. Formed.

  The length opposite to the side having the V-groove is cut out in a direction perpendicular to the core using a dicing saw (manufactured by DISCO; product number [DAD321]), the end face of the core is exposed, and a length having a 45 ° mirror portion on one side A 50 mm buried optical waveguide was obtained.

  An optical fiber with a light meter connected in a direction perpendicular to the film substrate surface is brought into contact with the end side of the core where the 45 ° mirror portion is formed and on the side opposite to the optical waveguide lamination surface of the polyimide film substrate, Light having a wavelength of 850 nm was introduced from the end of the core where the mirror portion was not formed, propagated through the core, and the intensity of the light reflected by the mirror portion was measured with a light meter. The waveguide loss was 1.2 dB.

  Since the V-groove was formed using the 1A mold and the 1B mold having the V-groove-corresponding convex portion, the surface of the V-groove was uniform and the mirror portion was easily formed by using the second mold. We were able to. Since the mirror part was formed using gold foil, the surface of the mirror part was also uniform, and the waveguide loss could be made very small.

Example 2
In order to create the second mold of the present invention (FIG. 9A), the surface of the phosphor bronze plate is cut, and the height of the convex portion corresponding to the convex portion (height from the apex angle to 12) is 100 μm. A concave portion corresponding to an oblique mirror having a width of 10 mm was formed, and a phosphor bronze mold B having the same shape as the V groove shape was produced. This mold B is a mold for the second mold. On the glass substrate (thickness 2 mm), with the gap, the phosphor bronze mold B is placed upside down, and without interposing bubbles in the gap between the glass substrate and the phosphor bronze mold, A two-part curable silicone rubber (trade name “SILPOT 184” manufactured by Toray Dow Corning Co., Ltd.) is injected and filled, and left to stand at room temperature for 24 hours to be cured. A mold was produced.

  Instead of the second glass mold having a suction mechanism, a second mold made of rubber (material two-component curable silicone rubber (trade name “SILPOT 184” manufactured by Toray Dow Corning Co., Ltd.) (FIG. 9) is used. A buried optical waveguide having a length of 50 mm was obtained in the same manner as in Example 1 except that (see (A)) was used, and the waveguide loss was measured in the same manner as in Example 1. The result was 1.4 dB. It was.

  In Example 2, the second mold made of rubber was used, but the gold foil (Au) could be pseudo-adhered to the convex part of the second mold. Further, by pressing the second mold 12 against the lower clad layer 3, the gold foil was transferred to the upper clad material surface of the core side slope of the V groove. By irradiating UV from the second mold 12 under the same conditions as described above, the upper clad material can be cured to form the upper clad layer, and a mirror part of a gold foil can be formed on the core side slope of the V groove. It was.

Example 3
A first mold 1 having a core groove-corresponding convex portion and no V-groove corresponding convex portion is manufactured, and the lower clad having the core groove is the same as in Example 1 except that this first die is used. A layer was formed, a core was formed, and an upper clad layer was formed (see the steps in FIGS. 2 to 3). Set a V-shaped diamond blade (count # 2000) with a vertex angle of 90 ° on a dicing saw (manufactured by DISCO; product number [DAD321]), and rotate the core at a spindle speed of 30000 rpm and a cutting speed of 0.3 mm / s. A V-groove was formed at one end of the core so that the apex of the blade would be at a depth of 95 μm from the surface of the upper clad layer in a direction perpendicular to the surface (see FIG. 4A). Subsequently, a UV curable epoxy resin (1) is applied as an upper clad material on the core 2 and the lower clad layer 3 of the laminate 6 with a spin coater so as to have a film thickness of 20 μm. The upper cladding layer 5 was cured by performing UV irradiation.

  Next, while using the glass 2nd type | mold 12 which has the suction mechanism used in Example 1 (refer FIG. 18), gold | metal foil was made to adsorb | suck to the convex part 13 like Example 1. FIG.

  Subsequently, a thermosetting epoxy adhesive was applied to the slope 7A of the V groove 7 with a spin coater so that the film thickness was 20 μm. Next, the gold foil 14 of the convex portion 13 of the second mold 12 was pressed against the adhesive layer formed on the core-side inclined surface 7A of the V-groove 7 for the mirror portion (the same process as FIG. Is different from the present embodiment in which an adhesive is applied to the slope 7A in that an adhesive is laminated on the metal film side). At this time, alignment is performed in the same manner as in Example 1, and after the second die 12 is pressed against the V-groove, the suction from the suction portion is stopped, and the adhesive layer on the core-side slope 7A of the V-groove 7 is stopped. The gold foil 14 was transferred to the surface of 15. Subsequently, the adhesive was cured (150 ° C., 30 minutes) to form a gold foil mirror portion on the core-side slope 7A of the V-groove 7.

  The length opposite to the side having the V-groove is cut out in a direction perpendicular to the core using a dicing saw (manufactured by DISCO; product number [DAD321]), the end face of the core is exposed, and a length having a 45 ° mirror portion on one side A 50 mm buried optical waveguide was obtained.

  An optical fiber with a light meter connected in a direction perpendicular to the film substrate surface is brought into contact with the end side of the core where the 45 ° mirror portion is formed and on the side opposite to the optical waveguide lamination surface of the polyimide film substrate, Light having a wavelength of 850 nm was introduced from the end of the core where the mirror portion was not formed, propagated through the core, and the intensity of the light reflected by the mirror portion was measured with a light meter. The waveguide loss was 1.2 dB.

Comparative Example 1
A laminated body of a core and a lower clad layer was produced in the same manner as in Example 1. Next, the synthesized gold nano ink was dropped, and the entire V groove 7 was filled using the capillary phenomenon. After heating on a hot plate at 70 ° C. for 10 minutes, it was heated in a thermostatic bath at 150 ° C. for 30 minutes to form a gold coating film (oblique mirror part) on both slopes of the V groove 7.

  Subsequently, a UV curable epoxy resin (1) was applied by a spin coater so as to have a film thickness of 20 μm on the laminated body of the core and the lower clad layer having the oblique mirror portion obtained above, The upper cladding layer was cured by UV irradiation under the same conditions.

  The length opposite to the side having the V-groove is cut out in a direction perpendicular to the core using a dicing saw (manufactured by DISCO; product number [DAD321]), the end face of the core is exposed, and a length having a 45 ° mirror portion on one side A 50 mm buried optical waveguide was obtained.

  An optical fiber with a light meter connected in a direction perpendicular to the film substrate surface is brought into contact with the end side of the core where the 45 ° mirror portion is formed and on the side opposite to the optical waveguide lamination surface of the polyimide film substrate, Light having a wavelength of 850 nm was introduced from the end of the core where the mirror portion was not formed, propagated through the core, and the intensity of the light reflected by the mirror portion was measured with a light meter. The waveguide loss was 1.5 dB.

Comparative Example 2
The same as Comparative Example 1 except that the gold nano-colloidal solution was not used, the portions other than the V-groove were masked, a gold coating film having a thickness of 100 nm was formed by vapor deposition, and the mirror portion was formed by removing the masking. Thus, an embedded optical waveguide having a length of 50 mm was obtained. When the waveguide loss was measured in the same manner as in Example 1, it was 1.2 dB.

Comparative Example 3
In the same manner as in Example 3, after forming the lower clad layer having the core groove, the core, and the upper clad layer, a V-groove was formed at one end of the core with a dicing saw. Next, the same gold nano ink solution as in Comparative Example 1 was dropped, and the entire V groove was filled using the capillary phenomenon. After heating on a hot plate at 70 ° C. for 10 minutes, it was heated in a thermostatic bath at 150 ° C. for 30 minutes to form a gold coating film (oblique mirror part) on both slopes of the V groove 32.

  The length opposite to the side having the V-groove is cut out in a direction perpendicular to the core using a dicing saw (manufactured by DISCO; product number [DAD321]), the end face of the core is exposed, and a length having a 45 ° mirror portion on one side A 50 mm buried optical waveguide was obtained.

  When the waveguide loss was measured in the same manner as in Example 1, it was 3.5 dB. It was found that the surface of the V-groove formed by the dicing saw was very rough visually. For this reason, it is considered that the waveguide loss has increased.

Comparative Example 4
The same as Comparative Example 3 except that the gold nano-colloid solution was not used, but masking was performed on portions other than the V-groove, a gold coating film having a thickness of 100 nm was formed by vapor deposition, and the mirror portion was formed by removing the masking. Thus, an embedded optical waveguide having a length of 50 mm was obtained. When the waveguide loss was measured in the same manner as in Example 1, it was 4.5 dB. The surface of the V-groove formed with the dicing saw was very rough, and the deposited film was inferior in adhesion to the epoxy resin, and part of the film was peeled off. It is done. If sealing is further performed with an epoxy resin or the like after the mirror portion is formed, the waveguide loss can be further suppressed.

  If electrical wiring is provided on the back side of the substrate of the optical waveguide, it can be used as an opto-electric hybrid board, such as mobile phones, personal computers, digital cameras, etc. Applicable to the field.

DESCRIPTION OF SYMBOLS 1 1st type | mold 1 '1st type | mold 1A 1A type | mold 1W Vertical wall 2 Core 2A Core groove corresponding convex part 2B Core groove 3 Lower clad layer 3A (after hardening) Lower clad layer 4 Substrate 5 Upper clad layer 5A Upper clad material 6 Laminate (lower clad layer, core, upper clad layer)
7 Mirror part V-groove 7A Mirror part slope 8 Vertical end face 9 Mirror part material 10A, 10B Slant mirror part corresponding convex part 11A, 11B 1B type 12 Second mold 13 Diagonal mirror part corresponding convex part 14 Metal film 15 Adhesive 16 Diagonal mirror part 17, 17A Core material 70 Slit 71 Inlet

Claims (6)

A method of manufacturing an optical waveguide in which an oblique mirror portion is formed on at least one end of a core,
Pressing the uncured clad layer formed on the substrate with the first mold having a convex portion corresponding to the core groove, curing the clad layer as it is, and forming the core groove in the lower clad layer;
Releasing the first mold from the lower cladding layer, injecting and filling a core material into the core groove, and curing the core material in the core groove;
After the core material is cured, the upper clad material is dropped on the core and the lower clad layer and cured to form a laminate of the lower clad layer, the core, and the upper clad layer;
Forming an oblique mirror portion V-groove corresponding to the oblique mirror portion in a direction perpendicular to the contact with at least one end in the longitudinal direction of the laminate;
A step of attaching a metal film to a convex portion of the second mold having a convex portion that can contact the inclined surface on the core side of the V groove for the oblique mirror portion;
Attaching an adhesive to the inclined surface of the V-groove for the oblique mirror part and / or the surface of the second type metal film;
A step of pressing the second mold to which the metal film is adhered against the slope on the core side of the V-groove, and attaching the metal film to the slope of the V-groove via an adhesive to form a mirror portion. Manufacturing method of optical waveguide. In the manufacturing method of the optical waveguide according to claim 1,
The step of forming the core groove includes a convex portion corresponding to the core groove and a convex portion corresponding to at least one end of the convex portion corresponding to the core groove and corresponding to an oblique mirror portion extending in a direction perpendicular to the convex portion corresponding to the core groove. In the step of pressing the uncured cladding layer formed on the substrate and curing the cladding layer as it is to form the core groove and the oblique mirror portion V-groove in the lower cladding layer. Yes,
The step of curing the core material is a step of releasing the mold 1A from the lower clad layer, injecting and filling the core material into the core groove, and curing the core material in the core groove,
The step of forming the laminated body and the step of forming the V-groove include: after the core material is cured, after the upper clad material is applied on the core and the lower clad layer, the oblique mirror portion in the type 1A After pressing the 1B mold having only the same shape of the protrusions corresponding to the protrusion 1B so that the protrusions of the 1B mold contact the V groove of the lower cladding layer, the upper cladding material is cured. The method for manufacturing an optical waveguide according to claim 1, wherein the laminated body is formed and a V-groove is formed. A method of manufacturing an optical waveguide in which an oblique mirror portion is formed on at least one end of a core,
A type 1A having a convex portion corresponding to the core groove, and a convex portion corresponding to an oblique mirror portion extending in a direction orthogonal to the core groove corresponding convex portion, in contact with at least one end of the core groove corresponding convex portion, Pressing the clad layer before curing formed on the substrate, curing the clad layer as it is, and forming a core groove and an oblique mirror V groove in the lower clad layer;
Releasing the first A mold from the lower cladding layer, injecting and filling a core material into the core groove, and curing the core material in the core groove;
After the core material is cured, the upper clad material is applied on the inclined surfaces of the oblique groove V groove, the core, and the lower clad layer;
A convex part that can contact the slope of the V-groove for the slant mirror part is pressed against the slope of the V-groove so that the convex part comes into contact with the slope of the V-groove. A step of transferring a metal film to the surface of the upper cladding material of the V-groove to form a mirror portion;
A method of manufacturing an optical waveguide, comprising: a step of releasing a second mold after curing a clad material. In the manufacturing method of the optical waveguide according to claim 3,
Curing the core material comprises:
Releasing the first mold from the lower clad layer, and injecting and filling a core material into the core groove and the V-groove for the oblique mirror portion;
The 1B type having only the convex part having the same shape as the convex part corresponding to the oblique mirror part in the type 1A is used as the V groove of the lower clad layer in which the core material is filled in the core groove and the oblique mirror part V groove. The method of manufacturing an optical waveguide according to claim 3, wherein the first A-type convex portion is pressed against the V-groove to remove the core material, and then the core material in the core groove is cured.   The optical waveguide according to claim 1, wherein the metal film is at least one metal foil selected from the group consisting of gold, silver, copper, aluminum, and an alloy containing one or more of these. Production method.   An optical waveguide having an oblique mirror portion formed at least at one end of a core, wherein the mirror portion is formed of a metal foil.