JP2015099329A - Optical waveguide, opto-electric hybrid board and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide, an opto-electric hybrid board and electronic equipment that can efficiently propagate light.SOLUTION: An optical waveguide 1 comprises: a laminate 10 in which a clad layer 11 and a core layer 13 having a core part 14 formed therein are laminated; and a notch 170 that is formed from the clad layer 12 side to the core part 14, and includes an inclined surface 171 inclining with respect to an axial line of the core part 14. The inclined surface 171 has a curved convex surface protruding inside the notch 170 and satisfies a relationship of r1≠r2, where r1 denotes a radius of curvature of a center part 174a of the curved convex surface, and r2 denotes a radius of curvature of an outer edge part 174b thereof.

Description

  The present invention relates to an optical waveguide, an opto-electric hybrid board, and an electronic device.

  Conventionally, as a method of manufacturing an optical waveguide having an inclined surface (mirror surface), a second cladding is applied to a laminate in which a first cladding layer, a core layer on which a core portion is formed, and a second cladding layer are stacked. A method of forming an inclined surface by cutting an optical waveguide from a layer side with a tapered blade to form a notch is known (for example, see Patent Documents 1 and 2). However, in the optical waveguides of Patent Documents 1 and 2, since the mirror surface is flat, the light reflected by the mirror surface cannot be collected, and the light propagated through the core layer is efficiently extracted by the inclined surface. I can't.

JP 2008-304870 A Japanese Patent Application Laid-Open No. 11-258953

  An object of the present invention is to provide an optical waveguide, an opto-electric hybrid board, and an electronic apparatus that can efficiently propagate light.

Such an object is achieved by the present inventions (1) to (8) below.
(1) a laminate in which a cladding layer and a core layer in which a core portion is formed are laminated;
A notch having an inclined surface that is formed from the cladding layer side to the core portion and is inclined with respect to the axis of the core portion,
The optical waveguide is characterized in that the inclined surface has a curved convex surface protruding into the cutout, and a curvature radius of a central portion of the curved convex surface is different from a curvature radius of an outer edge portion.

  (2) The optical waveguide according to (1), wherein the inclined surface satisfies a relationship of r1 <r2, where r1 is a radius of curvature of a central portion of the curved convex surface and r2 is a radius of curvature of an outer edge portion.

  (3) The optical waveguide according to (1) or (2), wherein a radius of curvature r1 of the central portion is 0.1 to 500 μm.

  (4) The optical waveguide according to any one of (1) to (3), wherein a protruding height of the curved convex surface is 0.1 to 100 μm.

  (5) The optical waveguide according to any one of (1) to (4), wherein the central portion has an etching rate lower than that of the outer edge portion.

  (6) The optical waveguide according to any one of (1) to (5), wherein the central portion is a flat surface.

(7) The optical waveguide according to any one of (1) to (6) above,
An opto-electric hybrid board, comprising: an electric wiring board laminated on the optical waveguide and provided with electric wiring on a surface thereof.

  (8) An electronic apparatus comprising the opto-electric hybrid board according to (7).

According to the present invention, an optical waveguide capable of efficiently transmitting light can be obtained.
In addition, according to the present invention, a highly reliable opto-electric hybrid board and electronic apparatus having such an optical waveguide can be obtained.

It is a perspective view which permeate | transmits and shows 1st Embodiment of the optical waveguide of this invention. It is a longitudinal cross-sectional view of the optical waveguide shown in FIG. It is a cross-sectional view of the optical waveguide shown in FIG. It is a longitudinal cross-sectional view which shows the other structural example of the mirror which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of 2nd Embodiment of the optical waveguide of this invention. It is a longitudinal cross-sectional view of 3rd Embodiment of the optical waveguide of this invention. It is a figure which shows the manufacturing method of a core layer, the concentration distribution c of the monomer in the width direction of an optical waveguide, the refractive index distribution n, and the etching rate e. It is a perspective view which shows typically an example of the laser processing apparatus used for manufacture of the optical waveguide of this invention. It is the top view which illustrated a mode that the mask for laser processing was moved relatively and a notch was formed. It is a longitudinal cross-sectional view which shows embodiment of the opto-electric hybrid board | substrate of this invention.

  Hereinafter, the optical waveguide, the opto-electric hybrid board and the electronic apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Optical waveguide>
<< First Embodiment >>
First, a first embodiment of the optical waveguide of the present invention will be described.

  FIG. 1 is a partially transparent perspective view showing a first embodiment of an optical waveguide according to the present invention, FIG. 2 is a longitudinal sectional view of the optical waveguide shown in FIG. 1, and FIG. 3 is an optical waveguide shown in FIG. FIG. 4 is a transverse sectional view and FIG. 4 is a longitudinal sectional view showing another configuration example of the mirror according to the first embodiment.

  An optical waveguide 1 shown in FIG. 1 has a band shape, and transmits an optical signal between a light incident portion and a light emitting portion to perform optical communication.

  An optical waveguide 1 shown in FIG. 1 includes a laminate 10 in which a clad layer (first clad layer) 11, a core layer 13, and a clad layer (second clad layer) 12 are laminated from below. In the core layer 13, a long core portion 14 and a side clad portion 15 provided adjacent to the side surface are formed. As a result, the core part 14 is surrounded by the clad part (the side clad part 15 and the clad layers 11 and 12), and light can be confined and propagated in the core part 14. The optical waveguide 1 is provided with a notch 170 formed in the laminate 10. In the following, the surface on the cladding layer 11 side of the laminate 10 is referred to as a surface 10a, and the surface on the cladding layer 12 side is referred to as a surface 10b.

  Although the refractive index of the core part 14 should just be larger than the refractive index of a clad part, it is preferable that the difference is 0.3% or more, and it is more preferable that it is 0.5% or more. On the other hand, the upper limit value is not particularly set, but is preferably about 5.5%. If the difference in refractive index is less than the lower limit value, the effect of propagating light may be reduced. On the other hand, if the difference in refractive index exceeds the upper limit value, further improvement in light transmission efficiency cannot be expected.

  The refractive index difference is expressed by the following equation when the maximum refractive index of the core portion 14 is n4 and the minimum refractive indexes of the side cladding portion 15, the cladding layer 11, and the cladding layer 12 are n5, n1, and n2. Is done.

Refractive index difference (%) = | n4 / n5-1 | × 100
Refractive index difference (%) = | n4 / n1-1 | × 100
Refractive index difference (%) = | n4 / n2-1 | × 100

  Further, the refractive index distribution in the width direction of the core layer 13 (the thickness direction in FIG. 2) may be any shape distribution. That is, the refractive index distribution may be a so-called step index (SI) type distribution in which the refractive index changes discontinuously, or a so-called graded index (GI) type distribution in which the refractive index changes continuously. It may be. If the SI type distribution is used, it is easy to form a refractive index distribution. If the GI type distribution is used, the probability that the signal light is collected in a region having a high refractive index is increased, so that the transmission efficiency is improved.

  On the other hand, the refractive index distribution in the thickness direction of the optical waveguide 1 (vertical direction in FIG. 2) may be the above-described step index distribution or the above-described graded index distribution.

  Further, the core portion 14 may be linear or curved in plan view. Furthermore, the core part 14 may branch or cross | intersect on the way.

  The cross-sectional shape of the core portion 14 is not particularly limited, and may be a circle such as a perfect circle, an ellipse, or an oval, or a polygon such as a triangle, a quadrangle, a pentagon, or a hexagon. By being (rectangular), there is an advantage that the core portion 14 can be easily formed.

  The width and height (the thickness of the core layer 13) of the core part 14 are not particularly limited, but are preferably about 1 to 200 μm, more preferably about 5 to 100 μm. Thereby, it is possible to increase the density of the core part 14 while increasing the transmission efficiency of the core part 14. That is, since the number of core portions 14 that can be laid per unit area can be increased, large-capacity optical communication can be performed even in a small area.

  In addition, the number of the core parts 14 formed in the core layer 13 is not particularly limited, but is 1 to 100, for example.

  The constituent materials (main materials) of the core layer 13 and the cladding layers 11 and 12 as described above are, for example, acrylic ether, methacrylic resin, polycarbonate, polystyrene, cyclic ether resin such as epoxy resin and oxetane resin. , Polyamide, polyimide, polybenzoxazole, polysilane, polysilazane, silicone resin, fluorine resin, polyurethane, polyolefin resin, polybutadiene, polyisoprene, polychloroprene, polyester such as PET and PBT, polyethylene succinate, polysulfone, poly Various resin materials such as ethers and cyclic olefin resins such as benzocyclobutene resins and norbornene resins can be used. Note that the resin material may be a composite material in which materials having different compositions are combined. Since these are relatively easy to process, they are suitable as constituent materials for the core layer 13 and the cladding layers 11 and 12 in which the notches 170 are formed.

  The optical waveguide 1 is provided with a notch 170 in which a part of the laminated body 10 is removed from the surface 10b side. That is, the optical waveguide 1 includes the laminated body 10 and a notch 170 formed thereon. The notch 170 shown in FIG. 1 is located in the middle of the core part 14 in the longitudinal direction. The method for forming the notch 170 is not particularly limited, and can be formed by, for example, a patterning method using a photolithography technique and an etching technique, a laser processing method using a mask, or the shape of the notch 170. It can also be formed by an imprint method in which a mold (blade) corresponding to the above is pressed.

  As shown in FIG. 2, a part of the inner surface of the notch 170 is inclined surfaces (transverse sections) 171 and 172 that are inclined with respect to the axis A of the core portion 14. The inclined surface 171 functions as a mirror surface (optical path conversion unit) that converts the optical path of the core unit 14. The inclined surface 171 changes the propagation direction by reflecting light propagating from the right side to the left side in FIG. Note that the inclined surface 172 may be used as a mirror surface in the same manner as the inclined surface 171. Hereinafter, although the structure of the inclined surface 171 is demonstrated, the structure of the inclined surface 172 is also the same.

  As shown in FIGS. 2 and 3, the inclined surface 171 is positioned around the first region 174 crossing the core portion 14 and the first region 174, and the cladding portion (the side cladding portion 15 and each cladding layer 11, 12) and a second region 175 crossing.

  When a cross section F1 orthogonal to the inclined surface 171 intersecting the intersection of the axis A of the core portion 14 and the first region 174 is viewed from the surface 10b side (in the direction of arrow B in FIG. 2), as shown in FIG. The first region 174 has a central part 174a located at the central part of the core part 14, and an outer edge part 174b located at the edge part of the core part 14 and disposed around the central part 174a.

  When the radius of curvature (average radius of curvature) of the central portion 174a is r1, and the radius of curvature of the outer edge portion 174b is r2, the relationship r1 ≠ r2 is satisfied. In this embodiment, the relationship r1 <r2 is further satisfied. Is satisfied. In this way, by concentrating the curvature of the central portion 174a more than the curvature of the outer edge portion 174b, the light condensing effect of the central portion 174a is enhanced more than the outer edge portion 174b. In particular, in the core layer 13 having a graded index (GI) type distribution, light collects in the central portion of the core portion 14. Therefore, by making the curvature of the central part 174a tighter than the curvature of the outer edge part 174b, the light propagating through the core part 14 can be collected more effectively toward the light receiving part. Further, by reducing the curvature of the central portion 174a, the lens effect can be enhanced and the focal length can be shortened, so that the light receiving portion can be arranged closer. Therefore, loss can be reduced and downsizing can be achieved. Further, by increasing the curvature of the outer edge portion 174b, light transmission loss can be reduced and light can be propagated efficiently.

  Here, the curvature radius r2 is not particularly limited, but is preferably about 2 to 2000 μm, and more preferably about 5 to 1500 μm. Further, the curvature radius r1 is not particularly limited as long as it is smaller than the curvature radius r2, but is preferably less than about 0.1 to 500 μm, and more preferably less than about 0.2 to 100 μm. Thereby, said effect can be exhibited more effectively.

  The protrusion height G of the first region 174 is not particularly limited, but is preferably about 0.1 to 100 μm, more preferably about 0.2 to 45 μm, and 0.5 to More preferably, it is about 40 μm. Thereby, the protrusion height (gap between the outer edge and the center) G of the first region 174 can be suppressed. Therefore, the first region 174 can be retreated more deeply than the second region 175, and the notch 170 can be reduced in size.

  The notch 170 has been described above. The maximum depth D of the notch 170 is appropriately set based on the thickness of the laminated body 10 and is not particularly limited. However, from the viewpoint of the mechanical strength and flexibility of the optical waveguide 1, it is about 1 to 500 μm. It is preferable to set it to about 5 to 400 μm.

  Further, the maximum length L of the notch 170 is not particularly limited, but is about 2 to 1200 μm from the relationship between the thickness of the cladding layers 11 and 12 and the core layer 13 and the inclination angle of the inclined surfaces 171 and 172. It is preferable to set it to about 10 to 1000 μm.

  Furthermore, the maximum width W of the notch 170 is not particularly limited and is appropriately set according to the width of the core portion 14 and the like, but is preferably about 1 to 600 μm, more preferably about 5 to 500 μm. preferable.

  Note that one notch 170 may be provided for one core part 14, but one notch 170 may be provided so as to straddle the plurality of core parts 14.

  FIG. 4 is a longitudinal sectional view showing another configuration example of the mirror according to the first embodiment. In FIG. 1, the inclined surface 171 forms a mirror, whereas in FIG. 4, the inclined surface 171 and the reflective film 176 formed thereon form a mirror. . Otherwise, the optical waveguide 1 shown in FIG. 4 is the same as the optical waveguide 1 shown in FIG.

  By providing such a reflective film 176, the light reflection characteristics of the mirror can be particularly improved. Examples of the reflective film 176 include a metal film, a carbon film, a resin film, a ceramic film, and a silicon film. Among these, a metal film is preferably used. According to the metal film, the reflection film 176 having a high reflectance due to the gloss peculiar to the metal can be obtained. Examples of the constituent material of the metal film include aluminum, iron, chromium, nickel, copper, zinc, silver, platinum, gold, lead and the like.

  The average thickness of the reflective film 176 is not particularly limited, but is preferably about 0.1 to 500 μm, and more preferably about 0.5 to 300 μm. As a result, a reflective film that has sufficient reflectivity and is difficult to peel off can be obtained.

  Examples of the method for forming the reflective film 176 include a vacuum deposition method, a physical vapor deposition method such as a sputtering method, a chemical vapor deposition method such as a CVD method, a plating method, a thermal transfer method, a metal foil transfer method, a printing method, and a coating method. Etc.

<< Second Embodiment >>
Next, a second embodiment of the optical waveguide of the present invention will be described.
FIG. 5 is a longitudinal sectional view showing a second embodiment of the optical waveguide of the present invention.

  Hereinafter, although 2nd Embodiment is described, in the following description, difference with 1st Embodiment is demonstrated and the description is abbreviate | omitted about the same matter.

In the optical waveguide 1 according to the first embodiment described above, the inclined surface 172 is an inclined surface similar to the inclined surface 171, whereas in the optical waveguide 1 according to the present embodiment, the inclined surface 172 has an axis line. It is a flat upright surface 172 ′ that is substantially orthogonal to A.
In such a second embodiment, the same operations and effects as in the first embodiment can be obtained.

«Third embodiment»
Next, a third embodiment of the optical waveguide of the present invention will be described.
FIG. 6 is a longitudinal sectional view of a third embodiment of the optical waveguide of the present invention.

  Hereinafter, the third embodiment will be described. In the following description, differences from the first embodiment will be described, and description of similar matters will be omitted.

  The optical waveguide 1 according to the third embodiment shown in FIG. 6 further includes a support film 2 laminated on the lower surface (surface 10a) of the cladding layer 11, and a cover film laminated on the upper surface (surface 10b) of the cladding layer 12. 3 is provided.

Further, the notch 170 is configured to penetrate the cover film 3. Therefore, the inclined surface 171 is a surface formed continuously from the cover film 3 through the cladding layer 12 and the core layer 13 to the middle of the cladding layer 11.
In such a third embodiment, the same operation and effect as in the first embodiment can be obtained.

  Moreover, by using the support film 2 and the cover film 3, the laminated body 10 can be protected from external force, foreign matter adhesion, contamination, and the like.

  Moreover, since the inclined surface 171 includes the cross section of the cover film 3, it has a wider area. For this reason, it becomes easy to form the inclined surface 171 with higher accuracy. That is, as the surface to be processed is wider, the processing accuracy of the cross section of the core portion 14 can be easily increased. Therefore, according to the third embodiment, a mirror with particularly high reflection efficiency can be formed.

<Optical waveguide manufacturing method>
Next, a method for manufacturing the optical waveguide 1 will be described with reference to FIGS. FIG. 7 is a diagram showing a core layer manufacturing method and monomer concentration distribution c, refractive index distribution n, and etching rate e in the width direction of the optical waveguide, and FIG. 8 is a laser used for manufacturing the optical waveguide of the present invention. FIG. 9 is a perspective view schematically showing an example of a processing apparatus, and FIG. 9 is a plan view illustrating a state in which a cavity is formed by relatively moving a laser processing mask.

  The optical waveguide 1 shown in FIG. 1 has a notch formed by sequentially laminating a clad layer 11, a core layer 13 and a clad layer 12 to obtain a laminate 10 and a process of removing a part of the laminate 10. And a step of forming 170.

  [1] First, the core layer forming layer 7 including the polymer 21 and the monomer 22 having a higher refractive index than the polymer 21 is prepared on the substrate 30. In the core layer forming layer 7, as shown in FIG. 7A, the monomer 22 and the like are uniformly dispersed in the matrix made of the polymer 21. As the substrate 30, for example, a silicon substrate, a quartz substrate, a glass substrate, a polyethylene terephthalate (PET) substrate, a polyimide substrate, or the like is used.

  Examples of the polymer 21 include acrylic resins, methacrylic resins, polycarbonates, polystyrenes, cyclic ether resins such as epoxy resins and oxetane resins, polyamides, polyimides, polybenzoxazoles, polysilanes, polysilazanes, silicone resins, Fluorine resin, polyurethane, polyolefin resin, polybutadiene, polyisoprene, polychloroprene, polyester such as PET and PBT, polyethylene succinate, polysulfone, polyether, and cyclic olefins such as benzocyclobutene resin and norbornene resin These resins can be used, and one or more of these can be used in combination (as a polymer alloy, polymer blend (mixture), copolymer, etc.).

  On the other hand, the monomer (photopolymerizable monomer) 22 reacts in the irradiation region 71 to generate a reaction product by irradiation with actinic radiation R described later. At the same time, the monomer 22 moves to cause a refractive index difference between the irradiated region 71 and the non-irradiated region 72 of the core layer forming layer 7. The reaction product of the monomer 22 includes a polymer (polymer) formed by polymerizing the monomer 22 in the polymer 21, a crosslinked structure in which the monomer 22 is crosslinked with each other, and the monomer 22 is branched from the polymer 21. And at least one of the branched structures polymerized as described above. By the way, since the refractive index difference generated between the irradiated region 71 and the non-irradiated region 72 is generated based on the difference between the refractive index of the polymer 21 and the refractive index of the monomer 22, the monomer 22 has the refractive index of the polymer 21. It is selected in consideration of the magnitude relationship with.

  Such a monomer 22 is not particularly limited as long as it is a compound having a polymerizable site in the molecular structure, and examples thereof include acrylic acid (methacrylic acid) monomers, epoxy monomers, oxetane monomers, and norbornene monomers. A monomer, a vinyl ether monomer, a styrene monomer, a photodimerization monomer and the like can be mentioned, and one or more of these can be used in combination.

  Among these monomers 22, by using the same type of monomer as that for producing the polymer 21 described above, the monomer 22 can be more uniformly dispersed in the polymer 21. Easy to control the rate distribution. Further, unsaturated hydrocarbons are particularly preferably used as the polymerizable portion. A compound containing an unsaturated hydrocarbon tends to cause a polymerization reaction such as radical polymerization or cationic polymerization, and is suitable as the monomer 22 used in the present invention.

  [2] Next, as shown in FIG. 7B, the core layer forming layer 7 is irradiated with actinic radiation R through the mask 4 in which the opening (window) 41 is formed. As shown in FIG. 7E, the irradiated region 71 irradiated with the active radiation R becomes the side cladding portion 15, and the non-irradiated region 72 not irradiated with the active radiation R becomes the core portion 14. The exposure method may be contact exposure using a mask, proximity exposure, direct drawing method, or the like. The actinic radiation R is not limited as long as it can react with the monomer 22, and for example, in addition to visible light, ultraviolet light, infrared light, and laser light, an electron beam, an X-ray, or the like can be used.

  When the active radiation R is selectively applied to the irradiation region 71 of the core layer forming layer 7, the monomer 22 is polymerized in the irradiation region 71. When the monomer 22 is polymerized, the amount of the monomer 22 in the irradiation region 71 decreases, so that the monomer 22 in the non-irradiation region 72 moves to the irradiation region 71 as shown in FIG. . As a result, in the core layer forming layer 7, the concentration of the monomer 22 and its reactant in the irradiated region 71 increases, while in the non-irradiated region 72, the concentration of the monomer 22 decreases.

  Here, since the refractive index of the monomer 22 is lower than that of the polymer 21, the refractive index of the irradiated region 71 is lower than that of the non-irradiated region 72 by forming the concentration distribution as described above. . As a result, the refractive index difference that the refractive index of the irradiated region 71 is low and the refractive index of the non-irradiated region 72 is high is formed in the core layer forming layer 7, and the above-described refractive index distribution is formed. In addition, since the refractive index of the reaction product of the monomer 22 as described above is almost the same as the refractive index of the monomer 22 before polymerization (the refractive index difference is about 0 to 0.001), the monomer 22 As the polymerization proceeds, the refractive index decreases according to the amount of the monomer 22 and the amount of the reactant of the monomer 22.

  The movement of the monomer 22 is considered to be triggered by the consumption of the monomer 22 in the irradiation region 71. For this reason, it is considered that the monomers 22 in the entire non-irradiated region 72 do not move toward the irradiated region 71 all at once, but gradually move from a portion close to the irradiated region 71 and successively move so as to compensate for this. Therefore, the concentration distribution of the monomer 22 necessarily has a gentle slope. Furthermore, the refractive index distribution of the core layer forming layer 7 includes a low refractive index portion in which the refractive index near the boundary between the irradiated region 71 and the non-irradiated region 72 is relatively lowered, as shown in FIG. And a high refractive index portion in which the refractive index of the non-irradiated region 72 is relatively increased. Also, the refractive index of the central portion of the width of the irradiation region 71 is higher than that of the edge portion. Further, from the concentration distribution of the monomer 22 as described above, a distribution is also generated in the etching rate with a laser described later, and the etching rate is higher in the region where the concentration of the monomer 22 is higher.

  [3] Next, the core layer 13 is peeled from the substrate 30 and the clad layer 11 and the clad layer 12 are laminated via the peeled core layer 13 to obtain the laminate 10.

  [4] Next, the process which removes a part of laminated body 10 is given. Thereby, the notch 170 is formed and the optical waveguide 1 is obtained. There are various methods for forming the notch 170. For example, a laser processing method, an electron beam processing method, an imprint method, etc. other than machining methods, such as cutting and grinding, are mentioned. Among these, according to the laser processing method or the imprint method, the notch 170 with high dimensional accuracy can be formed relatively easily. Hereinafter, a method for forming the notch 170 by a laser processing method will be described.

  FIG. 8 is a perspective view schematically showing an example of a laser processing apparatus used for manufacturing the optical waveguide of the present invention, and FIG. 9 shows a state in which a notch is formed by relatively moving the laser processing mask. It is a top view.

  A laser processing machine (laser processing apparatus) 900 shown in FIG. 8 is opposite to a laser light source through a laser light source (not shown), a laser processing mask 910 arranged on the optical axis of the laser, and a laser processing mask 910. And a drive stage (not shown) that moves relative to the laser processing mask 910. Hereinafter, the configuration of each part of the laser processing machine 900 will be described in detail.

The laser light source is appropriately selected according to the wavelength of the oscillating laser. For example, various solid-state lasers such as YAG laser, YVO ₄ laser, Yb laser, and semiconductor laser, CO ₂ laser, He—Ne laser, and excimer laser. And various gas lasers.

  Moreover, although the wavelength of a laser is suitably set according to the constituent material of the laminated body 10, it shall be about 150-950 nm, for example.

  For example, an XY stage or a linear actuator is used as the drive stage. By moving the stacked body 10 placed on the drive stage relative to the laser processing mask 910, the laser irradiation region of the stacked body 10 can be scanned in an arbitrary pattern. Thereby, the laser irradiation for arbitrary time can be given with respect to the arbitrary positions of the laminated body 10. FIG.

  When the laser is irradiated, a vaporization reaction occurs in the irradiation region, and a concave portion is generated. Therefore, by scanning the irradiation region, the concave portions are continuously formed along the scanning trajectory, and finally the concave portion having an opening corresponding to the scanning trajectory is formed.

  Instead of moving the laminated body 10 with respect to the fixed laser processing mask 910, the laser processing mask 910 may be moved with the laminated body 10 fixed, or both may be moved. May be.

  The mask for laser processing 910 according to the present manufacturing method is a plate-like body, and includes a shielding part 911 that shields the laser and a transmission part 912 that transmits the laser. When laser is irradiated through the laser processing mask 910, a laser irradiation region is formed in the transmission part 912, and the laser is selectively irradiated to the region on the laminate 10 corresponding to the planar view shape of the transmission part 912. The Rukoto.

  Next, a method for forming the notch 170 in the laminate 10 using such a laser processing mask 910 will be described.

  The laser processing mask 910 shown in FIG. 8 is used so that the laser is irradiated while the transmission part 912 moves relatively along the longitudinal direction of the core part 14. FIG. 9 intermittently shows the position of the transmission part 912 during the movement.

  When the transmission part 912 (laser) moves along a locus as shown in FIG. 9, a notch 170 is formed according to the locus of the irradiation region, and the optical waveguide 1 is obtained. As described above, the etching rate distribution as shown in FIG. 7E is generated in the core layer 13, and the etching rate at the center part of the core part 14 is lower than the etching rate at the outer edge part of the core part 14. . Therefore, the outer peripheral part of the core part 14 is removed more than the center part, and as a result, the 1st area | region 174 of the curved convex surface which satisfies the relationship r1 <r2 is formed. Further, since the etching rate of the central part of the core part 14 is higher than the etching rate of the side clad part 15, the core part 14 is removed more than the side clad part 15, and as a result, retreats from the second region 175 to the back. A first region 174 is formed. Further, since the etching rate of the side clad portion 15 is substantially constant except for the edge portion, the second region 175 having a substantially flat surface is formed as a result.

<Opto-electric hybrid board>
Next, an embodiment of the opto-electric hybrid board according to the present invention will be described.
FIG. 10 is a longitudinal sectional view showing an embodiment of the opto-electric hybrid board according to the present invention.

  An opto-electric hybrid board 100 shown in FIG. 10 has an optical waveguide 1, an electric wiring board 5 laminated thereon, and an adhesive sheet 9 that is interposed between them and adheres them.

  The adhesive sheet 9 is a sheet mainly composed of a thermosetting resin, and adheres the electric wiring substrate 5 and the optical waveguide 1 by curing.

  The electrical wiring board 5 has a multilayer substrate 50 including a core substrate 51 and build-up layers 52 laminated on both surfaces thereof, and a through hole 53 that penetrates the multilayer substrate 50 and functions as an optical through hole. doing. The through hole 53 is provided so as to overlap the notch 170 of the optical waveguide 1 in plan view.

  The core substrate 51 is a substrate that supports the electrical wiring substrate 5, and includes, for example, a polyimide resin, a polyamide resin, an epoxy resin, various vinyl resins, a polyester resin such as a polyethylene terephthalate resin, and the like. And various resin materials. In addition, paper, glass cloth, resin film, etc. are used as a base material, and this base material is impregnated with a resin material such as a phenol resin, a polyester resin, an epoxy resin, a cyanate resin, a polyimide resin, or a fluorine resin. In addition to insulating substrates used for composite copper-clad laminates such as glass cloth / epoxy copper-clad laminates, glass nonwoven fabrics / epoxy copper-clad laminates, polyetherimide resin substrates, polyethers It may be a heat-resistant / thermoplastic organic rigid substrate such as a ketone resin substrate or a polysulfone resin substrate, or a ceramic rigid substrate such as an alumina substrate, an aluminum nitride substrate, or a silicon carbide substrate.

  The core substrate 51 is formed with through wirings that electrically connect the build-up layers 52 stacked on both surfaces of the core substrate 51.

  On the other hand, the buildup layer 52 is formed by alternately laminating insulating layers 521 and conductor layers 522. The conductor layer 522 is patterned to form electrical wiring. In addition, the conductor layer 522 is formed with through wiring that connects the electrical wirings provided on both surfaces of the insulating layer 521.

  Each of the conductor layer 522 and the through wiring is made of a conductive material such as a simple metal such as copper, aluminum, nickel, chromium, zinc, tin, gold, silver, or an alloy containing these metal elements. . The insulating layer 521 is made of a silicon compound such as silicon oxide or silicon nitride, a resin material such as a polyimide resin or an epoxy resin, or the like.

  In this way, an electrical circuit that extends not only in the plane direction but also in the thickness direction can be constructed in the buildup layer 52, and the density of the electrical circuit can be increased.

  In addition, although such a multilayer substrate 50 may be formed by what kind of construction method, it is formed by various buildup construction methods, such as an additive method, a semi-additive method, and a subtractive method, as an example.

  The electrical wiring board provided in the opto-electric hybrid board of the present invention is not limited to the one including the multilayer board such as the electrical wiring board 5 described above. For example, the multilayer board is a single-layer electrical wiring board (rigid board). It may be replaced, or may be replaced with various flexible substrates such as a polyimide substrate, a polyester substrate, and an aramid film substrate. The multilayer substrate 50 can be replaced with a coreless multilayer substrate that does not include the core substrate 51. In the case of a flexible substrate, since the substrate itself has sufficient light transmittance, the through hole 53 that functions as an optical through hole may not be formed. In this case, a structure other than the through hole 53 can be used as a work position reference in a work process described later.

  Further, the electric wiring board 5 has a solder resist layer 54 provided on the upper surface of the multilayer board 50. By providing the solder resist layer 54, the conductor layer 522 of the electrical wiring board 5 can be protected from oxidation, corrosion, and the like. In the solder resist layer 54, an opening (not shown) is formed at a connection portion with the conductor layer 522.

  The solder resist layer 54 is made of various resin materials and includes an inorganic filler as necessary. The average thickness of the solder resist layer 54 is not particularly limited, but is preferably about 10 to 100 μm, and more preferably about 20 to 50 μm. By setting the thickness of the solder resist layer 54 within the above range, the conductor layer 522 can be protected and the upper surface of the multilayer substrate 50 can be sufficiently smoothed.

  Here, in the manufacture of the opto-electric hybrid board 100, for example, the method in which the optical waveguide 1 in which the notch 170 is already formed and the electric wiring board 5 are bonded together by the adhesive sheet 9, and the notch 170 is not formed. There is a method in which after the optical waveguide 1 and the electric wiring substrate 5 are bonded together by the adhesive sheet 9, a notch 170 is formed in the optical waveguide 1 according to the through hole 53. In the former method, for example, the operator may attach the optical waveguide 1 and the electric wiring board 5 based on the positions while visually confirming the through hole 53 and the notch 170 with his / her own eyes, The optical waveguide 1 and the electrical wiring board 5 may be bonded together based on the positions of the through hole 53 and the notch 170 while visually recognizing the through hole 53 and the notch 170. On the other hand, in the latter case, after the optical waveguide 1 and the electric wiring board 5 are bonded together, the operator may perform processing based on the position while visually confirming the through-hole 53 with his / her own eyes. You may make it process based on the position, making the through-hole 53 visually recognized by an image recognition system. In addition, when the optical waveguide 1 is viewed from below, the through hole 53 can be seen through the optical waveguide 1 and the adhesive sheet 9, so that the above processing can be easily performed.

  Further, in the opto-electric hybrid board 100 shown in FIG. 10, the optical element 6 is mounted on the electric wiring board 5. The opto-electric hybrid board 100 and the optical element 6 constitute an optical module 1000. The opto-electric hybrid board 100 may be mounted with electric elements (not shown) such as IC, LSI, RAM, ROM, capacitor, coil, resistor, and diode.

  The optical element 6 includes an element body 60, a light emitting / receiving section 61 and a terminal 62 provided on the lower surface of the element body 60, and a bump 63 provided so as to protrude downward from the terminal 62. The light emitting / receiving unit refers to a light receiving unit, a light emitting unit, or a unit having both functions.

  The optical element 6 is arranged such that the optical axis of the light emitting / receiving unit 61 coincides with the optical axis of the core unit 14 via the inclined surface 171. Thereby, the optical waveguide 1 and the optical element 6 are optically connected, and the optical signal propagating through the optical waveguide 1 is received by the optical element 6, or the optical signal emitted from the optical element 6 is incident on the optical waveguide 1. You can do it.

  Further, the bump 63 is connected to the conductor layer 522. Thereby, the optical element 6 is mechanically fixed, the terminal 62 of the optical element 6 and the conductor layer 522 are electrically connected, and the operation of the optical element 6 can be controlled from the electric wiring board 5 side. Has been. The conductor layer 522 is configured such that the arrangement of the bumps 63 and the light emitting / receiving portions 61 of the optical element 6 to be placed is the same as the arrangement of the conductor layer 522 and the through holes 53. As a result, the light emitted from the light emitting / receiving unit 61 passes through the through hole 53 and reliably reaches the inclined surface 171, and the light reflected by the inclined surface 171 also passes through the through hole 53 and is received. The light emitting unit 61 is reliably reached.

  Examples of the optical element 6 include a light emitting element such as a surface emitting laser (VCSEL), a light emitting diode (LED), and an organic EL element, and a light receiving element such as a photodiode (PD, APD).

<Electronic equipment>
The optical waveguide according to the present invention as described above has high transmission efficiency and excellent optical coupling efficiency with other optical components. For this reason, by providing the optical waveguide of the present invention, a highly reliable electronic device (electronic device of the present invention) capable of performing high-quality optical communication can be obtained.

  Examples of the electronic device including the optical waveguide of the present invention include electronic devices such as a mobile phone, a game machine, a router device, a WDM device, a personal computer, a television, and a home server. In any of these electronic devices, it is necessary to transmit a large amount of data at high speed between an arithmetic device such as an LSI and a storage device such as a RAM. Therefore, since such an electronic device includes the optical waveguide of the present invention, problems such as noise and signal degradation peculiar to electric wiring are eliminated, and a dramatic improvement in performance can be expected. This can contribute to cost reduction.

  In addition, the amount of heat generated in the optical waveguide portion is greatly reduced compared to electrical wiring. For this reason, the electric power required for cooling can be reduced and the power consumption of the whole electronic device can be reduced.

  The optical waveguide, the opto-electric hybrid board, and the electronic device of the present invention have been described above. However, the present invention is not limited to this, and for example, an arbitrary component may be added to the optical waveguide.

  In addition, when the inclined surface 171 is used as a light incident side mirror, the light emitting side may emit light from the end surface of the core portion 14 along the axis of the core portion 14. A connector may be attached. On the other hand, when the inclined surface is used as a light output side mirror, the light incident side may be configured to make light incident along the axis of the core portion 14 from the end surface of the core portion 14. At that time, a connector may be attached to the incident end.

  In addition, a plurality of inclined surfaces may be formed in the optical waveguide. For example, when two inclined surfaces are formed, one inclined surface can be used as a light incident side mirror, and the other inclined surface can be used as a light emitting side mirror.

DESCRIPTION OF SYMBOLS 1 Optical waveguide 10 Laminated body 10a Surface 10b Surface 11 Clad layer 12 Clad layer 13 Core layer 14 Core part 15 Side surface clad part 170 Notch 171 Inclined surface 172 'Upright surface 172 Inclined surface 174 1st area | region 174a Central part 174b Outer edge part 175 Second region 176 Reflective film 2 Support film 21 Polymer 22 Monomer 3 Cover film 30 Substrate 4 Mask 5 Electric wiring substrate 50 Multilayer substrate 51 Core substrate 52 Build-up layer 521 Insulating layer 522 Conductive layer 53 Through-hole 54 Solder resist layer 6 Optical element 60 element body 61 light emitting / receiving section 62 terminal 63 bump 7 core layer forming layer 71 irradiated area 72 non-irradiated area 9 adhesive sheet 100 opto-electric hybrid board 900 laser processing machine 910 laser processing mask 911 shielding section 912 transmitting section 100 Optical module A axis B arrow D up to a depth F1 sectional F2 surface G protrusion height R actinic radiation L maximum length W maximum width

Claims (8)

A laminate in which a cladding layer and a core layer in which a core portion is formed are laminated;
A notch having an inclined surface that is formed from the cladding layer side to the core portion and is inclined with respect to the axis of the core portion,
The optical waveguide is characterized in that the inclined surface has a curved convex surface protruding into the cutout, and a curvature radius of a central portion of the curved convex surface is different from a curvature radius of an outer edge portion.   2. The optical waveguide according to claim 1, wherein the inclined surface satisfies a relationship of r <b> 1 <r <b> 2, where r <b> 1 is a curvature radius of a central portion of the curved convex surface and r <b> 2 is a curvature radius of an outer edge portion.   The optical waveguide according to claim 1 or 2, wherein a radius of curvature r1 of the central portion is 0.1 to 500 µm.   The optical waveguide according to any one of claims 1 to 3, wherein a protruding height of the curved convex surface is 0.1 to 100 µm.   The optical waveguide according to claim 1, wherein the central portion has a lower etching rate than the outer edge portion.   The optical waveguide according to claim 1, wherein the central portion is a flat surface. The optical waveguide according to any one of claims 1 to 6,
An opto-electric hybrid board, comprising: an electric wiring board laminated on the optical waveguide and provided with electric wiring on a surface thereof.   An electronic apparatus comprising the opto-electric hybrid board according to claim 7.

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