JP2014219536A - Optical waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide that can easily measure the deviation between a core pattern and an upper clad layer of the optical waveguide or the thickness of the core pattern and upper clad layer.SOLUTION: An optical waveguide 10 includes a lower clad layer 20, a core pattern 30 provided on the lower clad layer 20, and an upper clad layer 40, where the upper clad layer 40 further includes a core pattern marker 35 that is partially overlapped on an upper clad pattern 41 formed into a pattern and provided to partially protrude from the upper clad pattern 41.

Description

  The present invention relates to an optical waveguide and a method for inspecting an optical waveguide.

  With the increase in information capacity, development of an optical interconnection technology that uses optical signals not only for communication fields such as trunk lines and access systems but also for information processing in routers and servers is underway. Specifically, in order to use light for short-distance signal transmission between boards in a router or a server device or in a board, an opto-electric composite board in which an optical transmission path is combined with an electric wiring board has been developed. As an optical transmission line, it is desirable to use an optical waveguide that has a higher degree of freedom of wiring and can be densified than an optical fiber, and in particular, an optical waveguide that uses a polymer material with excellent workability and economy. Is promising.

As described in Patent Document 1, there is a type of optical waveguide in which a core pattern is formed on a lower cladding layer, the core pattern is covered with an upper cladding layer, and the upper cladding layer is patterned.
When the core layer and the upper clad layer are patterned as in the optical waveguide described in Patent Document 1, generally, the core layer and the upper clad layer are patterned in separate steps. For this reason, in order to confirm whether or not a failure in transmitting an optical signal or a failure in mounting an optical waveguide occurs, it is necessary to grasp the misalignment amounts of those layers.
When the optical waveguide is fitted to a connector or various housings, the optical waveguide is used to transmit and receive an optical signal between the core pattern and the light emitting / receiving element or a separate optical transmission path (for example, an optical fiber). It is also important to grasp the thickness of each layer that constitutes.

JP 2012-155035 A

However, in the optical waveguide described in Patent Document 1, since both the core pattern and the upper cladding layer are highly transmissive resins and the refractive index difference is small, it is difficult to visually recognize them as separate members. It was difficult to measure the deviation. In addition, in order to measure the thickness of each layer of the optical waveguide, the substrate was cut and the thickness of each layer exposed on the cut surface was measured. However, it was necessary to observe the cut surface, and the work was complicated. It was.
The present invention has been made to solve these problems, and provides an optical waveguide capable of easily measuring the misalignment of the core pattern with respect to the upper clad layer, the thickness of the core pattern and the upper clad layer, and a measuring method thereof. For the purpose.

As a result of intensive studies, the present inventors have provided a core pattern marker and a clad pattern formed by patterning the upper clad layer on the core pattern marker, and a part of the core pattern marker is formed as a clad pattern. It has been found that the above-mentioned problems can be solved by overhanging, and the present invention has been completed.
That is, the present invention
(1) An optical waveguide comprising a lower cladding layer, and a core pattern and an upper cladding layer provided on the lower cladding layer,
An optical waveguide further comprising a core pattern marker that is partly embedded in an upper clad pattern obtained by patterning the upper clad layer and that part of the upper clad layer extends from the upper clad pattern.
(2) The optical waveguide according to (1), wherein an overhanging portion that protrudes from the upper clad pattern of the core pattern marker is disposed so as to face when viewed along a predetermined direction.
(3) The optical waveguide according to (2), wherein the projecting portions are arranged so as to face each other when viewed along a direction different from the predetermined direction.
(4) The upper clad pattern includes an upper clad pattern marker provided separately from the upper clad pattern in which the core pattern is embedded,
The optical waveguide according to any one of (1) to (3), wherein a part of the core pattern marker is embedded in the upper clad pattern marker, and a part of the core pattern marker is projected from the upper clad pattern marker.
(5) The optical waveguide according to (4), wherein the core pattern marker is formed in a ring shape or a frame shape, and the upper cladding pattern marker is filled therein.
(6) The optical waveguide according to any one of (1) to (5), wherein an outline of the core pattern marker is similar to an outline of the upper cladding pattern.
(7) When viewed in the thickness direction, at least one of a lower cladding pattern marker and an electrical wiring marker, at least a part of which is disposed on the outer peripheral side of the core pattern marker, is provided, The optical waveguide according to any one of (1) to (6) above, wherein the lower cladding layer is patterned.
(8) An inclined surface that is continuous with the protruding portion and the upper cladding pattern so as to straddle a step at the boundary between the protruding portion of the core pattern marker protruding from the upper cladding pattern and the upper cladding pattern. The optical waveguide according to any one of the above (1) to (7).
(9) The optical waveguide according to (8), wherein the inclined surface provided in the projecting portion and the inclined surface provided in the core pattern marker are on the same plane.
(10) The optical waveguide according to any one of (8) and (9), wherein the inclined surface is formed by cutting.
(11) An optical path conversion mirror having an inclined surface is provided on the core pattern, and the inclined surface of the core pattern is flush with the inclined surface provided on the projecting portion and the inclined surface provided on the core pattern marker. The optical waveguide according to any one of (8) to (10) above.
(12) The optical waveguide according to any one of (1) to (11), wherein the core pattern and the core pattern marker are formed by photolithography.
(13) The optical waveguide inspection method according to (1) to (12) above,
A method for inspecting an optical waveguide, wherein the misalignment between the core pattern marker and the upper cladding pattern is measured, and the measured value is used as the misalignment between the core pattern and the upper cladding layer.
(14) The optical waveguide inspection method according to (8) to (11) above,
A method for inspecting an optical waveguide, comprising: observing the optical waveguide in a thickness direction; measuring a length of an inclined surface of the projecting portion; and measuring a thickness of the core pattern from the length.
(15) The method for inspecting an optical waveguide according to (13) or (14), wherein the optical waveguide is observed using epi-illumination and / or transmitted illumination.
Is to provide.

  According to the present invention, it is possible to easily measure the misalignment of the core pattern with respect to the upper cladding layer or the thickness of the core pattern in the optical waveguide.

It is sectional drawing of the optical axis perpendicular direction which shows the optical waveguide which concerns on the 1st Embodiment of this invention. It is a top view which shows the optical waveguide which concerns on the 1st Embodiment of this invention. FIG. 5 is a plan view showing a method for detecting a deviation amount ΔX in the first embodiment of the present invention. It is sectional drawing of the optical axis perpendicular direction which shows the optical waveguide which concerns on the 2nd Embodiment of this invention. It is a top view which shows the optical waveguide which concerns on the 2nd Embodiment of this invention. It is a top view which shows the optical waveguide which concerns on the 3rd Embodiment of this invention. It is a top view which shows the optical waveguide which concerns on the 4th Embodiment of this invention. It is sectional drawing of the optical axis perpendicular direction which shows the optical waveguide which concerns on the 5th Embodiment of this invention. It is a top view which shows the optical waveguide which concerns on the 5th Embodiment of this invention. It is sectional drawing of the optical axis perpendicular direction which shows the optical waveguide which concerns on the 6th Embodiment of this invention, Comprising: The optical waveguide before a notch groove is formed is shown. It is a top view which shows the optical waveguide which concerns on the 6th Embodiment of this invention, Comprising: The optical waveguide before a notch groove is formed is shown. It is sectional drawing of the optical axis parallel direction which shows the optical waveguide which concerns on the 6th Embodiment of this invention. It is a top view which shows the optical waveguide which concerns on the 6th Embodiment of this invention, Comprising: The optical waveguide after a notch groove is formed is shown. It is a top view which shows an example of the appearance when inspecting the optical waveguide which concerns on the 6th Embodiment of this invention. It is a top view which shows the optical waveguide which concerns on the 7th Embodiment of this invention, Comprising: The optical waveguide before a notch groove is formed is shown. It is a top view which shows the optical waveguide which concerns on the 7th Embodiment of this invention, Comprising: The optical waveguide after a notch groove is formed is shown. It is a top view which shows an example of an appearance when inspecting the optical waveguide which concerns on the 7th Embodiment of this invention.

Hereinafter, the present invention will be described with reference to embodiments.
(First embodiment)
1 and 2 are views for explaining an optical waveguide according to a first embodiment of the present invention.
As shown in FIGS. 1 and 2, the optical waveguide 10 according to the first embodiment includes a substrate 11, a lower cladding layer 20 formed on the substrate 11, and a core formed on the lower cladding layer 20. The pattern 30 and the upper cladding layer 40 formed on the lower cladding layer 20 are provided so as to embed the core pattern 30.
Further, the optical waveguide 10 includes a core pattern marker 35, and a measurement marker 50 is configured by the core pattern marker 35 and an upper clad pattern marker 45 formed by patterning the upper clad layer 40.

As shown in FIGS. 1 and 2, the core pattern 30 is an elongated member extending along the Y direction, for example, and a plurality of core patterns 30 are provided, but one core pattern 30 may be provided. Each core pattern 30 is used by transmitting an optical signal therein.
The upper clad layer 40 is patterned to form an upper clad pattern 41. The upper clad pattern 41 is an upper clad pattern for core embedding provided at the center of the substrate 11 so as to embed the core pattern 30 therein. 42 and an upper clad pattern marker 45 provided separately from the core clad upper clad pattern.
In the present embodiment, the lower cladding layer 20 is provided on the entire surface of the substrate 11, and each measurement marker 50 is provided on the lower cladding layer 20.
In the present embodiment, the lower clad layer 20 is not patterned but is provided on the entire surface of the substrate 1. However, the lower clad layer 20 may be patterned as necessary. In the case of patterning, the measurement marker 50 does not need to be stacked on the lower cladding layer 20, and for example, a part or all of the measurement marker 50 may be directly formed on the substrate 11.

Hereinafter, each member in the first embodiment will be described in more detail.
[substrate]
The optical waveguide 10 has the substrate 11 to provide the optical waveguide with toughness, and when the optical waveguide is formed with an inclined surface using a dicing saw or the like, the optical waveguide 10 can be prevented from breaking. There is an effect that the lower clad layer can be used as a foundation for patterning.
From the above viewpoint, the material of the substrate 11 that can be used in the optical waveguide of the present invention is not particularly limited, and includes, for example, a glass epoxy resin substrate, a ceramic substrate, a glass substrate, a silicon substrate, a plastic substrate, a metal substrate, and a resin layer. Examples include a substrate, a substrate with a metal layer, a plastic film, a plastic film with a resin layer, a plastic film with a metal layer, and an electric wiring board.
When it is desired to impart flexibility to the optical waveguide, the substrate 1 having flexibility and toughness may be used as the substrate 11, for example, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyethylene, polypropylene, and polyamide. Preferable examples include polycarbonate, polyphenylene ether, polyether sulfide, polyarylate, liquid crystal polymer, polysulfone, polyethersulfone, polyetheretherketone, polyetherimide, polyamideimide, and polyimide.
The thickness of the substrate 11 is not particularly limited, but if it is 5 μm or more, there is an advantage that the strength as a carrier film is easily obtained, and if it is 200 μm or less, there is an advantage that a low-profile optical waveguide can be obtained. From the above viewpoint, the thickness of the substrate 1 is more preferably in the range of 10 to 100 μm.
When measuring the amount of misalignment of each layer of the optical waveguide and the thickness of each layer, when irradiating transmitted light from the substrate 11 side, the substrate 1 is preferably transparent to the transmitted light wavelength.

[Lower cladding layer and upper cladding layer]
The lower clad layer 20 and the upper clad layer 40 are formed from a clad layer forming resin. The resin for forming the cladding layer is not particularly limited as long as it is a resin that has a lower refractive index than the core pattern 30 and is cured by light and / or heat, and a thermosetting resin or a photosensitive resin is preferably used. it can. In the resin for forming the clad layer, the resin constituting each of the lower clad layer 20 and the upper clad layer 40 may be composed of the same component or different components, and the resins having the same refractive index are different. It may be.
The method for patterning the lower clad layer 20 and the upper clad layer 40 is not particularly limited, but may be formed by photolithography, and the clad layer forming resin in this case may be a photosensitive resin composition.

  The method for laminating the clad layer forming resin layer is not particularly limited. For example, the clad layer forming resin may be laminated by dissolving the clad layer forming resin in a solvent. A film may be laminated. In the case of application, the method is not limited, and the clad layer forming resin may be applied by a conventional method. The clad layer forming resin film used for laminating can be easily manufactured by, for example, dissolving the clad layer forming resin in a solvent, applying the resin on the carrier film, and removing the solvent.

  The thicknesses of the lower cladding layer 20 and the upper cladding layer 40 are not particularly limited, but the thickness after pattern formation is preferably in the range of 5 to 500 μm. When the thickness after pattern formation is 5 μm or more, the cladding thickness necessary for light confinement can be secured, and when it is 500 μm or less, a low-profile optical waveguide can be obtained. From the above viewpoint, the thickness of the lower cladding layer 20 and the lower cladding layer 40 is more preferably in the range of 10 to 100 μm. The thickness of the lower clad layer forming resin film and the upper clad layer forming resin film for forming the lower clad layer 20 and the upper clad layer 40 is not particularly limited as long as the above-described thickness pattern can be formed. However, the thickness of the resin film is preferably 500 μm or less from the viewpoint of easily obtaining a resin film having a uniform film thickness.

[Core pattern]
The core pattern 30 can be formed, for example, by laminating a resin layer for forming a core layer and exposing and developing it. The core layer forming resin preferably has a refractive index higher than that of the lower cladding layer 20 and the upper cladding layer 40 and can be patterned by actinic rays. The method for forming the core layer forming resin layer before patterning is not limited. For example, the core layer forming resin may be laminated by dissolving the resin for forming the core layer in a solvent. A resin film may be laminated.

The thickness of the core pattern 30 is not particularly limited. However, if the thickness of the core pattern 30 after the formation is 10 μm or more, the alignment tolerance is increased in coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed. If it is 100 μm or less, there is an advantage that the coupling efficiency is improved in coupling with the light emitting / receiving element or the optical fiber after the optical waveguide is formed. From the above viewpoint, the thickness of the core pattern 30 is preferably in the range of 30 to 90 μm, and if the thickness of the resin film for forming the core layer is appropriately adjusted in order to obtain the thickness, the thickness is uniform. From the viewpoint of easily obtaining a resin film having a film thickness, the thickness of the resin film is preferably 500 μm or less.
As the core layer forming resin, it is preferable to use a resin that is transparent to an optical signal to be used and can form a pattern with actinic rays.

[Measurement marker]
In this embodiment, the measurement marker 50 includes a core pattern marker 35 stacked on the lower cladding layer 20 and an upper cladding pattern marker 45 formed by patterning the upper cladding layer 40. The core pattern marker 35 is partly embedded in the upper clad pattern marker 45 and partly provided so as to protrude from the upper clad pattern marker 45, thereby forming an overhang portion 36.
The measurement marker 50 is used when the optical waveguide 10 is inspected, and is not used as a member that transmits an optical signal.

[Manufacturing method of core pattern marker]
The core pattern marker 35 is formed in the same process using photolithography processing as the core pattern 30 used for optical signal transmission. Specifically, the core pattern marker 35 is formed by forming a core pattern layer forming resin on the lower clad layer 20 and exposing it to patterning by exposing with the same photomask. 30 and patterned.
Thereby, the relative position of the core pattern 30 with respect to the core pattern marker 35 is maintained as designed. Therefore, the shift amount of the core pattern marker 35 with respect to the other members is the same as the misalignment amount of the core pattern 30 with respect to the other members.
Further, as is apparent from the above manufacturing method, the core pattern marker 35 is preferably formed of the same material (core layer forming resin) as the core pattern and has the same thickness.

[Method for manufacturing upper clad pattern marker]
The upper clad pattern marker 45 is formed in the same process as the core buried upper clad pattern 42 using photolithography.
Specifically, the upper clad pattern marker 45 is formed by forming a resin for forming the clad layer on the core pattern, exposing it with the same photomask when patterning by exposure, and thereafter etching the upper part for core embedding by etching or the like. The clad pattern 42 is patterned and formed. As a result, the pattern is formed while maintaining the correlation between the positions of the core cladding upper cladding pattern 42 and the upper cladding pattern marker 45. Therefore, the shift amount of the upper clad pattern marker 45 with respect to other members is the same as the shift amount of the core-embedded upper clad pattern 42 with respect to other members.
As is apparent from the above manufacturing method, the upper clad pattern marker 45 is preferably formed of the same material as the core burying upper clad pattern 41 and has the same thickness.

[Specific structure of measurement marker]
Next, the measurement marker will be described more specifically.
The measurement marker 50 of the present embodiment includes an annular core pattern marker 35 and an upper portion that is stacked so as to fill the inside of the annular ring and a part thereof is disposed on the inner peripheral portion of the core pattern marker 35. The clad pattern marker 45 is included. And the outer peripheral part of the core pattern marker 35 on which the upper clad pattern marker 45 is not laminated becomes an overhanging portion 36 exposed to the outside, and the overhanging portion 36 has an annular shape.

  The overhang portion 36 is exposed to the outside, and the outer peripheral contour 36A forms a boundary with the lower clad layer 20 having a different refractive index. Therefore, the outer peripheral contour 36A of the overhang portion 36 is easily visible. Furthermore, the inner peripheral contour 36 </ b> B of the overhang portion 36 forms a boundary line with the upper clad pattern marker 45. The boundary line is easily visible because both the core pattern marker 35 and the upper clad pattern marker 45 are exposed to the outside and the refractive index difference is different from each other.

  Here, the overhang portions 36 are disposed so as to face each other across another member (upper clad pattern marker 45) when viewed along a predetermined direction (for example, the X direction). Further, the overhanging portion 36 is disposed so as to face each other with another member interposed therebetween even when viewed along a direction (for example, the Y direction) different from the predetermined direction. In the present embodiment, with such a configuration of the overhanging portion 36, the amount of misalignment of the core pattern in two directions (for example, the X and Y directions) can be easily detected according to the inspection direction described later. In this specification, the Y direction is a direction parallel to the core pattern, for example, and the X direction is a direction perpendicular to the Y direction. The Z direction is the thickness direction of the substrate 11 and is a direction perpendicular to both the X direction and the Y direction.

[Inspection method of optical waveguide]
Next, a method for inspecting an optical waveguide will be described with reference to FIG. When inspecting the optical waveguide, first, the optical waveguide 10 is irradiated with light along the thickness direction (Z direction). When light is irradiated onto the optical waveguide 10, the outer peripheral contour 36A and the inner peripheral contour 36B of the overhang portion 36 are easily visually recognized or detected.
Next, a center point C1 along the X direction of the outer peripheral contour 36A and a center point C2 along the X direction of the inner peripheral contour 36B are detected, and a relative deviation amount ΔX of the center point C1 with respect to the center point C2 along the X direction is detected. Is detected. In the present embodiment, the center points C1 and C2 are the center positions of the longest distances among the outer peripheral contour 36A and the inner peripheral contour 36B (that is, the diameter of the outer peripheral contour 36A and the inner peripheral contour 36B parallel to the X direction). It is.
Here, the outer peripheral contour 36 </ b> A of the overhang portion 36 indicates the outer periphery of the core pattern marker 35 and is recognized as the contour of the core pattern marker 35, while the inner peripheral contour 36 </ b> B is the outer periphery of the upper clad marker 45. It is shown and recognized as the contour of the upper clad pattern marker 45. In addition, since the design positions of the center points C1 and C2 are normally designed at the same position, the shift amount ΔX along the X direction of the center points C1 and C2 is relative to the upper clad pattern marker 45 of the core pattern marker 35. It is detected as a relative displacement amount.
Each of the core pattern marker 35 and the upper clad pattern marker 45 is formed at the same time as each of the core pattern 30 and the core buried upper clad pattern 42, and has the same positional shift as the core pattern 30 and the core buried upper clad pattern 42. It is something to do. Therefore, the deviation amount ΔX can be a positional deviation amount with respect to the upper cladding pattern 41 of the core pattern 30 along the X direction.
Similarly, the relative displacement ΔY of the core pattern marker 35 relative to the upper cladding pattern marker 45 along the Y direction can also be detected, and the displacement ΔY is detected as the upper cladding pattern 41 of the core pattern 30 along the Y direction. The amount of misalignment with respect to. As described above, in this embodiment, it is possible to detect the amount of displacement of the core pattern 30 with respect to the upper cladding pattern 41 by a simple method.

In the present embodiment, an error may occur in the development process, and either the core pattern marker 35 or the upper clad pattern 45 may be formed with a size different from the design value. However, in the present embodiment, the misalignment amount is measured by comparing the two central points of each pattern (contour) with the central point of the design value as described above. For this reason, even when the markers 35 and 45 are formed in different sizes depending on the error, the error in measuring the shift amount can be reduced. Further, since the misalignment amount in two directions (X and Y directions) can be measured, the misalignment amount can be detected more accurately.
According to the configuration of the optical waveguide described above, the amount of deviation can be detected in three or more directions. However, since the amount of deviation on a plane can be grasped by measuring the amount of deviation in two axes, the amount of deviation in two directions. May be detected. Further, the direction in which the misalignment amount is measured is not limited to the X and Y directions, but may be any direction. However, it is preferable to detect the misalignment amounts in two orthogonal directions as in the present embodiment.

  In the present embodiment, the contour of the inner periphery of the core pattern marker 35 is embedded in the upper cladding pattern marker 45. As a result, the contour of the inner periphery is obscured, and erroneous measurement can be prevented. In the present embodiment, since the upper clad pattern marker 45 has a structure filled in the core pattern marker 35, the outline of the extra core pattern 35 is formed by the upper clad pattern marker 45 as described above. It becomes easy to embed.

(Second Embodiment)
4 and 5 show an optical waveguide in the second embodiment of the present invention.
In the second embodiment, the core pattern marker 35 has the same configuration as that of the first embodiment, but the upper cladding pattern marker and the upper cladding pattern for burying the core are integrally formed, and the integrated upper cladding pattern 41 is formed. It is said. Hereinafter, the second embodiment will be described with respect to differences from the first embodiment, and the description of the same points as the first embodiment will be omitted.

In the present embodiment, the upper clad pattern 41 is laminated on the inside of the annular core pattern marker 35 and the portion excluding the inner peripheral portion of the core pattern marker 35. That is, the upper clad pattern 41 is laminated so as to embed the outer periphery of the core pattern 30 and the core pattern marker 35. And the inner peripheral part of the core pattern marker 35 in which the upper clad pattern 41 is not laminated | stacked becomes the overhang | projection part 36 exposed outside. The overhanging portion 36 has an annular shape.
In the present embodiment, since the outer peripheral contour of the core pattern marker 35 is embedded in the upper clad pattern 41, erroneous measurement due to the outer peripheral contour is reduced.

The inner peripheral contour 36B and the outer peripheral contour 36A of the overhang portion 36 of the present embodiment are the boundary between the exposed overhang portion 36 and the lower clad layer 20 and the like, and the refractive indexes thereof are different. When viewed in the direction, it is easily visible. In this embodiment, the overhanging portion 36 sandwiches the lower cladding layer when viewed along a predetermined direction (for example, the X direction) and a direction different from the predetermined direction (for example, the Y direction), respectively. It arrange | positions so that it may mutually oppose.
With such a configuration of the overhanging portion 35, in this embodiment as well, the amount of misalignment of the core pattern 30 in the two directions (X and Y directions) can be easily detected as in the first embodiment. In the detection of the positional deviation amount, the inner peripheral contour 36B is recognized as the contour of the core pattern marker 35, and the outer peripheral contour 36A is recognized as the contour of the upper clad pattern 41. This is done by detecting the quantities ΔX, ΔY. Since the detailed detection method is the same as that of the first embodiment, the description thereof is omitted.

In the first and second embodiments, the contour of the core pattern mark 35 is similar to the contour of the upper clad pattern marker 45 or the clad pattern 41, thereby facilitating measurement of the misalignment amount. .
If the core pattern marker 35 has an annular shape as in the first and second embodiments described above, the outline of the core pattern mark 35 is similar to the outline of the upper cladding pattern 41 or the upper cladding pattern marker 45. It becomes easy.
However, in the first and second embodiments described above, the core pattern marker 35 is not limited to an annular shape, and may be another ring shape such as an elliptical ring, a rectangular frame shape such as a rectangular frame, or a polygonal frame. Various frame shapes such as shapes may be used.

(Third embodiment)
FIG. 6 shows an optical waveguide in the third embodiment of the present invention.
Hereinafter, a difference between the third embodiment and the first embodiment will be described, and the description of the same points as the first embodiment will be omitted.

In the third embodiment, the core pattern marker 35 has a cross shape, and the upper clad pattern marker 45 superimposed on the core pattern marker 35 has a rectangular shape. In addition, a rectangle is used as a term including a rectangle and a square.
The upper clad pattern marker 45 is composed of four sides parallel to the X direction and the Y direction, and the cross-shaped core pattern marker 35 is embedded in the upper clad pattern marker 45 while the respective sides of the upper clad pattern marker 45 are embedded. The four projecting portions 36A to 36D are formed. The overhang portions 36A and 36C face each other in the X direction with the upper clad marker 45 interposed therebetween, and the overhang portions 36B and 36D face each other in the Y direction across the upper clad marker 45. In the present embodiment, by the configuration of the overhang portions 36A to 36D, the misalignment amount of the core pattern in the two directions (X and Y directions) can be easily detected as in the first embodiment.

  That is, the center point of the ends of the overhang portions 36A and 36C (that is, the outer peripheral contour of the overhang portion) along the X direction and the boundary line between the overhang portions 36A and 36C and the upper clad pattern marker 45 (the overhang portion of the overhang portion). The center point of the inner circumference contour) is detected, whereby the relative position of the core pattern marker with respect to the upper cladding pattern marker can be detected.

(Fourth embodiment)
FIG. 7 shows an optical waveguide in the fourth embodiment of the present invention.
Hereinafter, the difference between the fourth embodiment and the first embodiment will be described, and the description of the same points as in the first embodiment will be omitted.

In the fourth embodiment, the core pattern marker 35 has a rectangular square frame shape in which four frame sides are parallel to the X direction and the Y direction, and the upper clad pattern marker 45 has a cross shape. The upper clad pattern marker 45 has a cross shape extending in four directions along the X direction and the Y direction from the center of the core pattern 35, and the extending portions 45 </ b> A to 45 </ b> D extending in the four directions are provided on the core pattern marker 35. It arrange | positions so that each frame side may be straddled.
With such a shape, the frame side parallel to the X direction of the core pattern marker 35 has a portion that protrudes on both sides along the X direction from the extending portions 45B and 45D, and that portion constitutes the protruding portion 36. To do. Similarly, the frame side along the Y direction of the core pattern marker 35 has a portion projecting along the X direction from the extending portions 45 </ b> A and 45 </ b> C, and this portion becomes the projecting portion 36.

In the present embodiment, the center point between the outer peripheral contours 36A of the core pattern marker 35 (the overhang portion 36) and the boundary line 36B between the overhang portion 36 and the extension portion 45B (or 45D) along the X direction. , 36B is detected. Then, by calculating the shift amount of these center points, the shift amount ΔX in the X direction of the core pattern marker 35 with respect to the upper clad pattern marker 45 can be obtained.
Similarly, the amount of deviation ΔY in the Y direction of the core pattern marker 35 with respect to the upper clad pattern marker 45 can also be obtained, whereby the amount of deviation of the core pattern 30 with respect to the upper clad pattern 41 can be detected.

(Fifth embodiment)
8 and 9 show an optical waveguide in the fifth embodiment of the present invention.
Hereinafter, the fifth embodiment will be described with respect to differences from the first embodiment, and the description of the same points as the first embodiment will be omitted.
In the optical waveguide 10 of the present embodiment, as shown in FIG. 8, the lower cladding layer 20 is not provided on the entire surface of the substrate 11, but is a lower cladding pattern 21 formed by patterning.

The lower clad pattern 21 in the present embodiment is provided in the center of the substrate 11, and a core laminated lower clad pattern 22 on which an optical transmission core pattern 30 is laminated, and both sides of the core laminated lower clad pattern 22. And a lower clad pattern marker 25 that constitutes the measurement marker 50. The lower cladding pattern marker 25 is a marker for detecting a relative position of the lower cladding pattern 21 with respect to the core pattern 30, the upper cladding pattern 41, and the like.
Similarly to the upper clad pattern marker 45, the lower clad pattern marker 25 is formed by the same process as the core clad lower clad pattern 22 by photolithography. Therefore, it is preferably formed of the same material as the core cladding lower clad pattern 22 and has the same thickness.

  The lower clad pattern marker 25 only needs to have a shape having a protruding portion 26 protruding from the core pattern marker 35 when viewed in the thickness direction, whereby at least a part of the outer periphery of the core pattern marker 35 is provided. Placed on the side. In the present embodiment, the lower clad pattern marker 25 is designed to have a circular shape whose diameter is larger than the diameter of the core pattern marker 35, and the center position thereof coincides with the center position of the core pattern marker 35.

[Production method of lower clad pattern marker]
The lower clad pattern marker 25 is preferably formed in the same process as the core laminating lower clad pattern 22 using photolithography. For example, when the clad layer forming resin is exposed and patterned, it is preferable to expose with the same photomask. After that, if the core lamination lower clad pattern 22 and the lower clad pattern marker 25 are patterned by etching or the like, a pattern in which the correlation between the positions is maintained can be formed.

  In the present embodiment, the relative position (shift amount) of the core pattern 35 with respect to the lower cladding pattern 25 is such that the outer peripheral contour 26A of the overhang portion 26 of the lower clad pattern marker 25 and the outer peripheral contour 36A of the overhang portion 36 of the core pattern marker. It can measure by detecting. The method for detecting the relative position is the same as the method for detecting the relative position of the core pattern with respect to the upper clad pattern, and a description thereof will be omitted. Similarly, the relative position of the lower cladding pattern 21 with respect to the upper cladding pattern 41 can be detected.

In the present embodiment, the electrical wiring 60 is provided on the opposite side of the surface of the substrate 11 where the lower cladding layer 20 is formed. In the present embodiment, various electric circuits can be mounted on the optical waveguide 10 by the electric wiring 60. The electrical wiring 60 may be provided on the surface of the substrate 11 where the lower cladding layer 20 is formed. In this case, the lower clad layer 20 is usually laminated on the electric wiring 60.
As a method for forming the electric wiring 60, a metal layer is formed on the surface on which the electric wiring 60 is formed, an etching resist is further formed, and unnecessary portions of the metal layer are removed by etching (subtract method), and a plating resist is formed. And forming a thin metal layer (seed layer) on the surface on which the electric wiring 60 is formed, a method of forming the electric wiring 60 by plating only on a necessary portion of the surface on which the electric wiring 60 is to be formed (additive method), There is a method (semi-additive method) in which a plating resist is formed, and then an electric wiring 60 necessary for electroplating is formed, and then a thin metal layer is removed by etching. Any method may be used for forming the electrical wiring 60.

(Formation of seed layer in semi-additive process)
When forming the electrical wiring 60 by the semi-additive method, there are a method of forming a seed layer on a surface on which the electrical wiring 60 is formed, a method by vapor deposition or plating, and a method of bonding a metal layer.

(Formation of seed layer by vapor deposition or plating)
As described above, the seed layer can be formed on the surface on which the electrical wiring 60 is formed by vapor deposition or plating. For example, when a base metal and a thin film copper layer are formed by sputtering as a seed layer, the sputtering apparatus used to form the thin film copper layer is a bipolar sputtering, a three-pole sputtering, a four-pole sputtering, a magnetron sputtering, a mirror. Tron sputtering or the like can be used.
A target used for sputtering is sputtered 5 to 50 nm using, for example, a metal such as Cr, Ni, Co, Pd, Zr, Ni / Cr, or Ni / Cu as a base metal in order to ensure adhesion. Thereafter, a seed layer can be formed by sputtering 200 to 500 nm using copper as a target. Further, plated copper can be formed on the surface on which the electrical wiring is formed by electroless copper plating of 0.5 to 3 μm. In order to improve the adhesion between the seed layer and the surface on which the seed layer is formed, surface roughening may be performed before the seed layer is formed or when the seed layer is formed.

(Method of bonding metal layers)
When the surface on which the electric wiring is formed has an adhesive function, as described above, the seed layer can be formed by bonding the metal layer by pressing or laminating.
However, since it is very difficult to directly bond a thin metal layer, there are a method of thinning by etching after laminating a thick metal layer, a method of removing a carrier layer after laminating a metal layer with a carrier, etc. is there.
For example, the former has a three-layer copper foil of carrier copper / nickel / thin film copper, the carrier copper is removed with an alkali etching solution, nickel is removed with a nickel etching solution, and the latter is made of aluminum, copper, insulating resin, etc. The peelable copper foil or the like can be used, and a seed layer of 5 μm or less can be formed.
Alternatively, a 9 to 18 μm thick copper foil may be attached and the seed layer may be formed by etching to a uniform thickness so as to be 5 μm or less.
The type of electroplating used in the semi-additive method may be any commonly used one, and is not particularly limited. However, in order to form the electric wiring 60, it is preferable to use copper as the plating metal.

(Electrical wiring formation by additive method)
Even when the electrical wiring 60 is formed by the additive method, as in the semi-additive method, it is formed by plating only on a necessary portion of the surface on which the electrical wiring 60 is formed, but the plating used in the additive method is Usually, electroless plating is used.
For example, after depositing an electroless plating catalyst on the surface on which the electrical wiring 60 is to be formed, a plating resist is formed on a surface portion where plating is not performed, and the substrate is immersed in an electroless plating solution and covered with the plating resist. Electroless plating is performed only on the non-existing portions to form the electric wiring 60.
In order to improve the adhesion between the electric wiring 60 and the surface on which the electric wiring 60 is formed, a surface roughening treatment may be performed before the electroless plating catalyst is attached.

  The electrical wiring 60 obtained as described above may be further subjected to plating for protecting the electrical wiring such as Ni / Au plating or Ni / Pd / Au plating.

[Electric wiring marker]
In the present embodiment, an electrical wiring pattern marker 65 is provided on the surface of the substrate 11 opposite to the surface on which the lower cladding layer 20 is laminated, in addition to the electrical wiring 60. The electrical wiring pattern marker 65 is provided so as to be arranged at least partially on the outer peripheral side of the core pattern marker 35 when viewed in the thickness direction, and constitutes the measurement marker 50.
The shape of the electric wiring pattern marker 65 is not particularly limited. In the present embodiment, the electric wiring pattern marker 65 has a circular shape that is slightly larger than the circular lower cladding pattern marker 25, and the center position of the electric wiring pattern marker 65 is the core pattern marker. Designed to match the center position of 35.

[Method for manufacturing electrical wiring marker]
The electrical wiring marker 65 may be formed from the same material as the electrical wiring 65 in the same process using photolithography. For example, when a subtractive method, a semi-additive method, or an additive method is used, the patterning exposure of the etching resist or the plating resist may be performed using the same photomask. After that, if the electric wiring marker 65 and the electric wiring 60 are patterned by etching, plating, or the like, a pattern in which the correlation between the positions is maintained can be formed. Therefore, the electric wiring marker 65 is aligned with another marker or pattern. The deviation amount can be a misalignment amount of the electrical wiring 60.
For example, the relative position between the electric wiring 60 and the core pattern 35 is inspected by detecting the relative position between the outer peripheral contour 65A of the electric wiring marker 65 and the outer peripheral contour 36A of the core pattern marker 35 (the overhang portion 36). Is possible.

In the present embodiment, the optical waveguide needs to be observed using incident light when measuring the misalignment amount. The electrical wiring marker overlaps with the contour of another marker (for example, the core pattern marker). However, since the electrical wiring marker has a light shielding property, if the transparency is used from the side opposite to the viewing direction, the contour of the other marker is This is because it becomes impossible to observe.
Therefore, when transmitted light is used, the electrical wiring marker 65 is formed so as not to overlap at least the marker or pattern outline used for measurement of the lower cladding pattern marker 25, the core pattern marker 35, and the upper cladding pattern marker 45. For example, various ring shapes and various frame shapes can be mentioned.

  In the present embodiment, the lower cladding pattern marker 25 may be omitted, and the electrical wiring marker 65 may be omitted. When the lower clad pattern marker is omitted, the lower clad layer may or may not be patterned. When the electrical wiring marker is omitted, the electrical wiring may be omitted.

In each of the embodiments described above, two center points are detected, and the positional deviation is detected based on the center points. However, it is not necessary to detect the two center points. For example, in the first embodiment, the relative position of one predetermined position of the contour of the core pattern marker 35 with respect to the predetermined one position of the contour of the upper clad pattern marker 45 is measured, and the measured value is compared with the design value. Thus, the positional deviation amount may be grasped. In this case, when the size of the core pattern marker 35 or the upper clad pattern 45 is formed with a size different from the design value, the error increases, but it is preferable in that the position shift can be detected by a simple method.
In addition, the deviation amount detection method detects the relative position of at least a part of the contour of another member (for example, the upper clad pattern) with respect to at least a part of the contour of the core pattern marker and the like, Any method can be used as long as the method is performed by comparing with design values.

In addition, the shape of the core pattern marker 35 is not particularly limited, but the shape when viewed from the thickness direction is not limited to the ring shape, the frame shape, and the cross shape described above, but a polygonal shape such as a quadrangle, a circular shape, An elliptical shape, a star shape, a star frame shape, a straight line shape, a curved line shape, an arc shape, a shape obtained by combining them may be used.
However, when the area of the core pattern marker 35 is reduced as in the ring shape, cross shape, and frame shape of the first to third embodiments, the upper surface of the upper clad pattern marker 45 formed on the core pattern marker 35 is flat. It is more preferable because it is easy to ensure the property. If the pattern widths of the various ring shapes, the various frame shapes, and the cross shape are within ± 100 μm of the width of the core pattern 30 used for optical signal transmission, it is easier to ensure the flatness of the upper surface of the upper cladding pattern marker 45.

The shape of the upper clad pattern marker 45 is not particularly limited as long as it is a marker capable of exposing the core pattern marker 35 and forming the overhang portion 36, but the shape when viewed from the thickness direction is the circular shape described above. In addition to rectangles and crosses, various polygonal shapes, polygonal frame shapes such as rectangular frame shapes, elliptical shapes, ring shapes that exhibit circular shapes or ellipses, star shapes, star frame shapes, linear shapes, curved shapes, circles, etc. An arc shape, the shape which combined them, etc. may be sufficient.
The shape of the lower clad pattern marker 25 may be the same shape as the core pattern marker 35. However, since the lower clad pattern marker 25 is generally thin, it hardly affects the flatness of the upper surface of the core pattern marker 35 and the upper clad pattern marker 45, so that various ring shapes can be used to ensure flatness. The various shapes may not be used, but in the case of a thickness that affects the shape, a ring shape may be used.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIGS. In each of the above embodiments, the measurement marker 50 is formed to detect the amount of displacement, but in this embodiment, it is used to detect the thickness of the core pattern or the upper cladding pattern. Hereinafter, a difference between the sixth embodiment of the present invention and the first embodiment will be described.

In the present embodiment, two rectangular patterns of core pattern markers 35 of each measurement marker 50 are provided with an interval therebetween, and a rectangular upper cladding pattern marker 45 is disposed thereon. The upper clad marker 45 is provided so as to cover substantially half of each rectangular core pattern marker 35. Each core pattern marker 35 is provided so as to protrude outward in the X direction from the side of the upper clad marker 45 parallel to the Y direction, and forms an extended portion 36. Each core pattern marker 45 is shorter than the upper clad pattern marker 45 in the Y direction, and the upper clad pattern marker 45 protrudes from the core pattern marker 35 in the Y direction.
Further, the thickness of the core pattern marker 35 is smaller than the thickness of the upper clad marker 45, so that there is a step 47 at the boundary between the overhang portion 36 and the core pattern marker.
In the present embodiment, the core pattern marker 35 and the upper cladding pattern marker 45 have a shape in which a part thereof is cut out by a notch groove 70 described later.

In the present embodiment, a V-shaped notch groove 70 is formed in the optical waveguide 10.
The notch groove 70 is cut so as to cross the core pattern 30 embedded in the measurement markers 50, 50 and the core-embedded upper cladding pattern 42. That is, the core pattern 30 embedded in the core-embedded upper cladding pattern 42 has a V-shaped shape, and the two inclined surfaces 70A and 70B, which are groove side surfaces, have the core-embedded upper cladding pattern 42 and There is a core pattern 30 surrounded by the lower cladding layer 20, and an optical path conversion mirror 75 is formed by the core pattern 30. The optical path conversion mirror 75 may be an air reflection mirror or a metal reflection mirror in which a reflective metal layer is formed on an inclined surface.
Similarly, the measurement marker 50 has a V-shaped shape, and the upper clad pattern marker 45 and the core clad marker 35 are formed on the inclined surfaces 70A and 70B, which are the groove side surfaces of the notch groove 70. Both are exposed. As a result, the inclined surfaces 70A and 70B are provided on the same plane across the step 47 at the boundary between the overhang portion 36 and the upper clad pattern marker 45, and the overhang portion 35 and the upper clad pattern marker 45 are also inclined. It becomes a surface. These inclined surfaces are arranged on the same plane as the inclined surface of the optical path conversion mirror 12.
The notch groove 70 is cut from the upper clad layer 40 side to a depth that bites into the lower clad layer 20. Accordingly, the inclined surfaces 70A and 70B include the inclined surface of the lower cladding layer 20. The inclined surfaces 70 </ b> A and 70 </ b> B of the lower cladding layer 20 are continuous along the X direction. For example, the measurement marker 50 is provided so as to extend to both sides of the core pattern marker 35.
The inclined surfaces 70A and 70B are inclined surfaces that are inclined at 45 ° with respect to the optical axis direction, but may be other than 45 °, and may be greater than 0 ° and less than 90 °.
The method for forming the notch groove 70 is not particularly limited, and can be formed by laser ablation or cutting by a dicing saw. Forming with a dicing saw is more preferable because an inclined surface can be formed efficiently.

  Further, the cutout groove 70 is not provided so that all the upper surfaces of the overhang portion 36 and the upper clad pattern marker 45 are removed, and a part of the upper surface of the overhang portion 36 and the upper clad pattern marker 45 is left. Yes. Accordingly, the upper ends of the inclined surfaces of the upper clad pattern marker 45 and the core pattern marker 35 are connected to the overhang portion 36 and the upper surfaces 36U and 45U of the upper clad pattern marker 45, respectively. The upper surfaces 36U and 45U are surfaces parallel to the lower cladding layer.

  In the present embodiment, the inclined surface 70A is formed so as to straddle the step 47 as described above. Therefore, as shown in FIG. 14, even when the optical waveguide is viewed in the thickness direction, there appears to be a step 47 ′ at the connection portion between the inclined surface of the upper clad pattern marker 45 and the upper end of the overhang portion 36. This is because since the upper clad pattern marker 45 is relatively thick, the length of the inclined surface of the upper clad pattern marker 45 along the Y direction is inevitably long, and that portion is visually recognized as a step 47 ′. .

[Method for measuring core pattern thickness]
In the present embodiment, the thickness of the core pattern can be measured from the inclined surface provided on the measurement marker 50 as follows.
That is, in this embodiment, the optical waveguide is observed in the thickness direction, and the length L1 of the overhang portion 36 on the inclined surface 70A is measured. The length L <b> 1 is a length from the boundary between the core pattern marker 35 and the lower cladding layer 20 to the upper end of the core pattern marker 35.
Here, when the optical waveguide is viewed in the thickness direction, the boundary between the core pattern marker 35 and the lower cladding layer 20 on the inclined surface 70A is easy because the lower cladding layer 20 extends to both sides of the core pattern marker 35. Can be recognized. In addition, the upper end of the core pattern marker 35 can be easily recognized by the step 47 ′ described above. Therefore, the measurement of the length L1 is easy.
The length L1 can be converted into the thickness of the core pattern. When the inclined surface is inclined at an angle θ in a range larger than 0 ° and smaller than 90 °, the length × tan θ is the thickness of the core pattern.
Further, when the angle of the inclined surface is 45 °, the length L1 is the thickness of the core pattern.

[Method for measuring the thickness of the upper cladding pattern]
Measurement of the thickness of the upper clad pattern from the measurement marker 50 first detects the thickness of the upper clad pattern marker 45 laminated on the core pattern marker 35. Specifically, on the inclined surface 70A, the length L2 from the upper end of the core pattern marker 35 to the boundary between the upper surface 45U of the upper cladding pattern marker 45 and the inclined surface is measured. The length L2 can be converted into the thickness of the upper clad pattern marker 45 laminated on the core pattern marker 35, similarly to the length L1.
At this time, since there is a step 47 ′, the upper end of the core pattern marker 35 can be easily recognized. Further, since the upper surface 45U and the inclined surface of the upper clad pattern marker 45 have different light transmission and reflectance and look different from each other, and have the step 47 ′, the boundary between the upper surface 45U and the inclined surface 70A can be easily formed. Can be recognized.
Thereafter, the thickness of the upper clad pattern can be measured by adding the thickness of the upper clad pattern marker 45 laminated on the core pattern marker 35 to the thickness of the core pattern marker.
As another method, the length L3 from the lower cladding layer 20 to the upper surface 45U of the upper cladding pattern on the inclined surface 70A may be measured. Since the length measurement method is the same as described above, the description thereof is omitted.
In addition, although the example which used the marker on the inclined surface 70A demonstrated the measurement of the above length L1-L3, it is the same also when using the marker on the inclined surface 70B.

  The planar direction for measuring the thickness may be from the lower side (back surface of the substrate) or from the upper side (front surface of the substrate), but when the substrate 11 is not transmissive, it may be measured from the upper side. The illumination used at the time of measurement may be a transmission illumination or an epi-illumination, and they may be mixed at an arbitrary ratio. However, when the transmission illumination is used, as shown in FIG. Furthermore, since the inclined surface becomes a dark part and the contrast becomes clear, it is preferable because the measurement becomes easier.

(Seventh embodiment)
Next, a difference between the seventh embodiment of the present invention and the sixth embodiment will be described with reference to FIGS.
In the seventh embodiment, the upper clad pattern 41 is divided into three in the X direction, and is composed of first to third upper clad patterns 41A to 41C. The second upper clad pattern 41B at the center includes the core pattern 30 and Approximately half of the center side of the core pattern marker 35 on the center side of each measurement marker 50 is embedded. The first and third upper clad patterns 41 </ b> A and 41 </ b> C embed substantially half of the end side of the core pattern marker 35 on the end side of each measurement marker 50.
Accordingly, in each measurement marker 50, the core pattern marker 35 on the center side has an overhang portion 36 that projects from the second upper clad pattern 41B toward the end side. In addition, the core pattern marker 35 on the end side of each measurement marker 50 has an overhang portion 36 that projects from the first or third upper clad pattern 41A, 41C toward the center side.

  Also in the present embodiment, the boundary between the upper clad patterns 41 </ b> A to 41 </ b> C and the core pattern marker 35 has a step 47. Therefore, by providing the notch groove 70, the lengths L1 to L3 on the inclined surface 70A can be easily measured by the step 47 'when viewed in the thickness direction.

In addition, the shapes of the core pattern marker 35 and the upper clad pattern marker 45 in the sixth and seventh embodiments may be the shapes listed above. However, since the flatness of the thickness of the upper clad pattern 41 is important for obtaining an accurate thickness measurement result, the core pattern marker 35 has a linear shape, an arc shape, various ring shapes, various frame shapes, and the like. It is more preferable that the pattern has a small area.
Further, in the measurement markers 50 in the sixth and seventh embodiments, unlike the measurement markers in the first to fifth embodiments, the protruding portions 36 do not have to be provided to face each other in two directions. In the measurement markers in the sixth and seventh embodiments described above, the overhanging portion 36 only faces in the X direction. Of course, it is not necessary to face in one direction.

  In each of the above-described embodiments, two measurement markers 50 are provided so as to sandwich the core pattern 30 from both sides, so that the shift amount and thickness can be detected by each of the two measurement markers 50. The displacement and thickness can be detected with high accuracy. However, two measurement markers 50 need not be provided, and may be one.

[Shading layer]
In each of the above embodiments, a light shielding layer may be provided at a predetermined portion of the measurement marker. By providing the light shielding layer, it becomes easy to clearly recognize the boundary line between each layer and the step of the inclined surface. The light shielding layer may be laminated on the core pattern marker 35 and the upper clad pattern marker 45, for example, or may be laminated on the core pattern marker 35 and the upper clad pattern 41 around it. As the kind of the light shielding layer, it is only necessary to have a light shielding property with respect to the wavelength of the light source used for the measurement, such as a light shielding resin such as an ultraviolet absorbing resin layer, a visible light absorbing resin layer, an infrared absorbing resin layer, Au, Ag. A metal layer such as Cu, Al, Cr, Ni, or Pd is preferably used. The light-shielding resin can be formed by applying a light-shielding resin varnish or laminating a light-shielding resin film. As a method for forming the metal layer, plating, vapor deposition, sputtering, or the like may be used. In the case where a light shielding layer is formed and the amount of misalignment and the thickness of each layer are measured, epi-illumination is preferably used.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.
Example 1
<Preparation of a resin film for forming a cladding layer>
[Production of (A) (meth) acrylic polymer (base polymer)]
46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate were weighed in a flask equipped with a stirrer, a cooling pipe, a gas introduction pipe, a dropping funnel, and a thermometer, and stirred while introducing nitrogen gas. . The liquid temperature was raised to 65 ° C., 47 parts by weight of methyl methacrylate, 33 parts by weight of butyl acrylate, 16 parts by weight of 2-hydroxyethyl methacrylate, 14 parts by weight of methacrylic acid, 2,2′-azobis (2,4-dimethylvaleronitrile ) A mixture of 3 parts by mass, 46 parts by mass of propylene glycol monomethyl ether acetate and 23 parts by mass of methyl lactate was added dropwise over 3 hours, followed by stirring at 65 ° C. for 3 hours, and further stirring at 95 ° C. for 1 hour. A) A (meth) acrylic polymer solution (solid content: 45% by mass) was obtained.

[Measurement of weight average molecular weight]
(A) As a result of measuring the weight average molecular weight (in terms of standard polystyrene) of (meth) acrylic polymer using GPC (“SD-8022”, “DP-8020” and “RI-8020” manufactured by Tosoh Corporation), 3 9 × 10 ⁴ . As the column, “Gelpack GL-A150-S” and “Gelpack GL-A160-S” manufactured by Hitachi Chemical Co., Ltd. were used.
[Measurement of acid value]
As a result of measuring the acid value of (A) (meth) acrylic polymer, it was 79 mgKOH / g. The acid value was calculated from the amount of 0.1 mol / L potassium hydroxide aqueous solution required to neutralize the (A) (meth) acrylic polymer solution. At this time, the point at which the phenolphthalein added as an indicator changed color from colorless to pink was defined as the neutralization point.

[Preparation of resin varnish for forming clad layer]
As a base polymer, 84 parts by mass (solid content 38 parts by mass) of the (A) (meth) acrylic polymer solution (solid content 45% by mass), (B) urethane (meth) acrylate having a polyester skeleton as a photocuring component ( Shin-Nakamura Chemical Co., Ltd. “U-200AX”) 33 parts by mass, urethane (meth) acrylate having a polypropylene glycol skeleton (Shin-Nakamura Chemical Co., Ltd. “UA-4200”) 15 parts by mass, (C) heat As a curing component, 20 parts by mass of a polyfunctional block isocyanate solution (solid content: 75% by mass) obtained by protecting an isocyanurate type trimer of hexamethylene diisocyanate with methyl ethyl ketone oxime (“Sumijour BL3175” manufactured by Sumika Bayer Urethane Co., Ltd.) 15 parts by mass of solid content), (D) as photopolymerization initiator, 1- 4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (“Irgacure 2959” manufactured by Ciba Japan KK), 1 part by weight, bis (2,4,6- 1 part by mass of trimethylbenzoyl) phenylphosphine oxide (“Irgacure 819” manufactured by Ciba Japan Co., Ltd.) and 23 parts by mass of propylene glycol monomethyl ether acetate as an organic solvent for dilution were mixed with stirring. After pressure filtration using a polyflon filter having a pore diameter of 2 μm (“PF020” manufactured by Advantech Toyo Co., Ltd.), degassing was performed under reduced pressure to obtain a resin varnish for forming a cladding layer.

<Preparation of a resin film for forming a cladding layer>
The resin varnish for forming a clad layer obtained above is coated on a non-treated surface of a PET film (Toyobo Co., Ltd. “Cosmo Shine A4100”, thickness 50 μm) as a carrier film. MC, manufactured by Hirano Tech Seed Co., Ltd.), dried at 100 ° C. for 20 minutes, and then a surface release treatment PET film (“Purex A31” manufactured by Teijin DuPont Films Co., Ltd., 25 μm thick) is pasted as a cover film. A resin film for forming a cladding layer was obtained.
At this time, the thickness of the resin layer formed from the clad layer forming resin varnish can be arbitrarily adjusted by adjusting the gap of the coating machine, and the film thickness will be described later.

<Preparation of core layer forming resin film>
(A) As a base polymer, 26 parts by mass of phenoxy resin (trade name: Phenototo YP-70, manufactured by Toto Kasei Co., Ltd.), (B) 9,9-bis [4- (2-acryloyl) as a photopolymerizable compound Oxyethoxy) phenyl] fluorene (trade name: A-BPEF, manufactured by Shin-Nakamura Chemical Co., Ltd.) 36 parts by mass, and bisphenol A type epoxy acrylate (trade name “EA-1020”, manufactured by Shin-Nakamura Chemical Co., Ltd.) 36 1 part by mass of (C) photopolymerization initiator, 1 part by mass of bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (trade name “Irgacure 819”, manufactured by Ciba Specialty Chemicals) [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name “ Lugacure 2959 "(manufactured by Ciba Specialty Chemicals) 1 part by weight, except for using 40 parts by weight of propylene glycol monomethyl ether acetate as an organic solvent, in the same manner and under the same conditions as the above-mentioned preparation of the resin varnish for forming a cladding layer A resin varnish for forming a core layer was prepared. Thereafter, pressure filtration and degassing under reduced pressure were performed in the same manner and conditions as described above.
The resin layer varnish for core layer formation obtained above is the same as the above production example on the non-treated surface of a PET film (Toyobo Co., Ltd., trade name: Cosmo Shine A1517, thickness: 16 μm) as a carrier film. Then, a release PET film (trade name “Purex A31”, Teijin DuPont Films Co., Ltd., thickness: 25 μm) is pasted as a cover film so that the release surface is on the resin side. A resin film for layer formation was obtained.
At this time, the thickness of the resin layer formed from the resin varnish for forming the core layer can be arbitrarily adjusted by adjusting the gap of the coating machine, and the film thickness will be described later.

<Example of Fabrication of Optical Waveguide of First Embodiment (FIGS. 1 and 2)>

[Formation of lower cladding layer]
A 150 mm × 150 mm polyimide film (polyimide; Upilex RN (manufactured by Ube Nitto Kasei), thickness: 25 μm) was used as the substrate 11, and the 15 μm-thick clad layer-forming resin film obtained above was formed on one surface thereof. After peeling the cover film, using a vacuum pressurization laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.), evacuating to 500 Pa or less, pressure 0.4 MPa, temperature 110 ° C., pressurization time 30 seconds. The film was heat-pressed and laminated under the conditions. Subsequently, ultraviolet rays (wavelength 365 nm) were irradiated at 3.0 J / cm ² from the carrier film side of the resin film for forming the clad layer using an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.), and the carrier After peeling off the film, it was dried and cured at 170 ° C. for 1 hour to form the lower cladding layer 20.

[Formation of core pattern]
Next, the 50 μm-thick core layer-forming resin film obtained above is peeled off from the lower clad layer forming surface side formed above, and then the roll laminator (HLM, manufactured by Hitachi Chemical Technoplant Co., Ltd., HLM) is removed. -1500) is laminated under the conditions of a pressure of 0.4 MPa, a temperature of 50 ° C., and a laminating speed of 0.2 m / min, and then the above-described vacuum pressure laminator (manufactured by Meiki Seisakusho Co., Ltd., MVLP-500) is used. After vacuuming below, thermocompression bonding was performed under the conditions of a pressure of 0.4 MPa, a temperature of 70 ° C., and a pressurization time of 30 seconds.

Subsequently, ultraviolet rays (wavelengths) were passed from the carrier film side through the negative photomask having openings (50 mm × 50 μm × 3, a ring shape having an outer periphery of φ400 μm and an inner periphery of 300 μm) from the carrier film side. 365 nm) at 0.8 J / cm ² and then post-exposure heating at 80 ° C. for 5 minutes. Thereafter, the PET film as the carrier film was peeled off and etched using a developer (propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 8/2, mass ratio). Then, it wash | cleaned using the washing | cleaning liquid (isopropanol), and heat-dried at 100 degreeC for 10 minute (s), and the core pattern 302 and the core pattern marker 35 were formed.

[Formation of upper cladding layer]
The 65 μm-thick clad layer-forming resin film obtained above was peeled off from the core pattern forming surface side formed as described above, and then the vacuum pressure laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.) was peeled off. ), And was vacuum-bonded to 500 Pa or less, and then thermocompression bonded under the conditions of a pressure of 0.4 MPa, a temperature of 110 ° C., and a pressurization time of 30 seconds to laminate.
Subsequently, the core pattern marker 303 is aligned with the opening of the φ350 μm circle through a negative photomask having openings (50 mm × 1.1 mm × 1 place, φ350 μm circle × 2 places) to form a clad layer The resin film was irradiated with ultraviolet rays (wavelength 365 nm) at 350 mJ / cm ² from the carrier film side. Thereafter, the carrier film was peeled off, and the resin for forming the upper cladding layer was removed using a developer (1% aqueous potassium carbonate solution), followed by washing with water. Further, irradiation with 3.0 J / cm ² was performed using the above ultraviolet exposure machine, and heat drying and curing operations were performed at 170 ° C. for 1 hour. As a result, an upper cladding pattern 42 for burying the core and an upper cladding pattern marker 45 having a diameter of 350 μm were formed.

[Measurement of misalignment]
The obtained optical waveguide was visually recognized from the direction perpendicular to each layer formation surface on the upper clad layer side, and the measurement marker was visually confirmed by transmitted illumination of a white halogen lamp. Therefore, the misalignment amount of the upper clad pattern marker 45 with respect to the core pattern marker 35 was measured using the measurement marker. The positional deviation amount of the upper cladding pattern marker 45 is ΔX = +
It was 3.9 μm and ΔY = + 1.5 μm. The optical waveguide is cut and a core pattern 30 is separately provided.
As a result of measuring the misalignment amount between the core embedded upper cladding pattern 42 and the core embedding core 42, the correlation between the measured value and ± 0.5 μm was confirmed for both ΔX and ΔY.

[Visibility from other directions]
The obtained optical waveguide is viewed from the vertical direction of each layer forming surface on the lower clad layer side by epi-illumination of a white halogen lamp, and when the measurement marker is viewed from the vertical direction of each layer forming surface, the same as when viewed from the upper clad layer side It was good.

[Visibility from other directions]
The obtained optical waveguide was viewed from the vertical direction of each layer formation surface on the lower clad layer side by the transmitted illumination of a white halogen lamp, and when the measurement marker was viewed from the vertical direction of each layer formation surface, the same as when viewed from the upper clad layer side It was good.

Example 2
In Example 1, the metal mask having an opening of φ600 μm is aligned with the measurement marker 5, and Au is 0.5 μm as a light shielding layer using a vapor deposition apparatus (“RE-0025” manufactured by First Giken Co., Ltd.). A process of vapor deposition was performed.

[Measurement of misalignment]
The obtained optical waveguide was better when the measurement marker was viewed from the vertical direction of each layer formation surface by the epi-illumination of a white halogen lamp from the vertical direction of each layer formation surface on the upper clad layer side. Therefore, the misalignment amount of the upper clad pattern marker 45 with respect to the core pattern marker 35 was measured using the measurement marker. The positional deviation amount of the upper clad pattern marker 45 was ΔX = + 3.8 μm and ΔY = + 1.5 μm. When the optical waveguide was cut and the misalignment amount between the core pattern 30 and the upper upper cladding pattern 42 for core embedding was measured separately, both the above ΔX and ΔY could be confirmed to have a correlation within ± 0.5 μm with the measured values. Example 3
<Example of Fabrication of Optical Waveguide of Fifth Embodiment (FIGS. 8 and 9)>
[Formation of substrate with electrical wiring]
100 mm × 100 mm single-sided copper foil polyimide film (made by Nippon Steel & Sumikin Co., Ltd., trade name: MC12-25-00CEM (copper foil is made by Furukawa Electric Co., Ltd., trade name: F2-WS) ) Using a roll laminator (manufactured by Hitachi Chemical Technoplant Co., Ltd., HLM-1500) with a photosensitive dry film (manufactured by Hitachi Chemical Co., Ltd., trade name: Photec, thickness: 25 μm) on the copper foil surface of pressure) 0.4 MPa, temperature 110 Lamination was performed at a temperature of 1 ° C. and a laminating speed of 1.0 m / min. Then, using an ultraviolet exposure machine (EXM-1172 manufactured by Oak Manufacturing Co., Ltd.), ultraviolet rays (wavelength 365 nm) through a negative photomask having openings (50 mm × 150 μm × 1 location, φ500 μm circle × 2 locations). ) At 350 mJ / cm ² . Thereafter, the carrier film of the dry film was peeled off, the uncured dry film was developed and removed using a developer (1% aqueous sodium carbonate solution), and then the copper foil was etched with an aqueous ferric chloride solution. Further, the hardened dry film was peeled and removed with a stripping solution (3% sodium hydroxide aqueous solution) to form a linear electrical wiring 60 and an electrical wiring marker 65 of φ500 μm.

[Formation of lower cladding layer]
After the cover film is peeled off the 15 μm-thick clad layer-forming resin film obtained above on the surface of the substrate 11 opposite to the surface on which the electric wiring 60 is formed, a vacuum pressure laminator (manufactured by Meiki Seisakusho Co., Ltd. , MVLP-500), and evacuated to 500 Pa or less, and then laminated by thermocompression bonding under conditions of a pressure of 0.4 MPa, a temperature of 110 ° C., and a pressurization time of 30 seconds. Thereafter, the electrical wiring marker 65 is passed through a negative photomask having openings (50 mm × 1 mm × 1 place, φ450 μm circle × 2 places) using an ultraviolet exposure machine (EXM-1172, manufactured by Oak Manufacturing Co., Ltd.). And an opening of a circle of φ450 μm were aligned, and ultraviolet light (wavelength 365 nm) was irradiated at 350 mJ / cm ² from the carrier film side of the clad layer forming resin film. Thereafter, the carrier film was peeled off, and the lower clad layer forming resin was removed using a developer (1% aqueous potassium carbonate solution), followed by washing with water. Further, irradiation with 3.0 J / cm ² was performed using the above ultraviolet exposure machine, and heat drying and curing operations were performed at 170 ° C. for 1 hour. Thus, the lower clad pattern 22 and the lower clad pattern marker 25 having a diameter of 450 μm were formed.

[Formation of core pattern]
Next, the 65 μm-thick core layer-forming resin film obtained above is peeled off from the lower clad layer forming surface side formed above, and then the roll laminator (HLM manufactured by Hitachi Chemical Technoplant Co., Ltd., HLM) is peeled off. -1500) is laminated under the conditions of a pressure of 0.4 MPa, a temperature of 50 ° C., and a laminating speed of 0.2 m / min, and then the above-described vacuum pressure laminator (manufactured by Meiki Seisakusho Co., Ltd., MVLP-500) is used. After vacuuming below, thermocompression bonding was performed under the conditions of a pressure of 0.4 MPa, a temperature of 70 ° C., and a pressurization time of 30 seconds.

Subsequently, the center of the ring-shaped opening and the center of the electrical wiring marker 602 are passed through a negative photomask having openings (50 mm × 50 μm × 3, ring shape with an outer periphery of φ400 μm and an inner periphery of 300 μm). Alignment was performed, and irradiation with ultraviolet rays (wavelength 365 nm) was performed at 0.8 J / cm ² from the carrier film side using the above-described ultraviolet exposure machine, followed by heating at 80 ° C. for 5 minutes. Thereafter, the PET film as the carrier film was peeled off and etched using a developer (propylene glycol monomethyl ether acetate / N, N-dimethylacetamide = 8/2, mass ratio). Then, it wash | cleaned using the washing | cleaning liquid (isopropanol), and heat-dried at 100 degreeC for 10 minute (s), and the core pattern 30 and the core pattern marker 35 were formed.

[Formation of upper cladding layer]
After removing the cover film from the 85 μm-thick clad layer forming resin film obtained above from the core pattern forming surface side formed above, a vacuum pressure laminator (MVLP-500, manufactured by Meiki Seisakusho Co., Ltd.) ), And was vacuum-bonded to 500 Pa or less, and then thermocompression bonded under the conditions of a pressure of 0.4 MPa, a temperature of 110 ° C., and a pressurization time of 30 seconds to laminate.
Subsequently, via a negative photomask having openings (50 mm × 1.1 mm × 1 place, φ350 μm circle × 2 places), the electrical wiring marker 65 and the φ350 μm circle opening are aligned to form a clad layer The resin film was irradiated with ultraviolet rays (wavelength 365 nm) at 350 mJ / cm ² from the carrier film side. Thereafter, the carrier film was peeled off, and the resin for forming the upper cladding layer was removed using a developer (1% aqueous potassium carbonate solution), followed by washing with water. Further, irradiation with 3.0 J / cm ² was performed using the above ultraviolet exposure machine, and heat drying and curing operations were performed at 170 ° C. for 1 hour. As a result, an upper cladding pattern 42 for burying the core and an upper cladding pattern marker 45 of φ350 μm were formed.

[Measurement of misalignment]
When the obtained optical waveguide was viewed from the direction perpendicular to each layer formation surface by epi-illumination of a white halogen lamp from the upper clad layer side, it was slightly better. Therefore, the amount of misalignment of the pattern marker of each layer with respect to the core pattern marker 35 was measured using the measurement marker. The electrical wiring marker 65 is ΔX = + 2.5 μm, ΔY = −2.2 μm, the lower cladding pattern marker 25 is ΔX = −5.5 μm, ΔY = −1.7 μm, and the upper cladding pattern marker 45 is ΔX. = + 1.2 μm, ΔY = −0.4 μm. These confirmed the correlation between the actually measured misalignment amount of the core pattern 30 and the pattern of each layer and the correlation within ± 0.5 μm in both the X direction and the Y direction.

Example 4
<Example of Fabrication of Optical Waveguide of Fifth Embodiment (FIGS. 10-14)>
In Example 1, the shape of the core pattern marker 35 is 100 μm (X direction) × 500 μm (Y direction) × 2 (gap 150 μm) × 2 locations, and the shape of the upper cladding pattern marker 45 is 250 μm (X direction) × 700 μm. An optical waveguide was manufactured in the same manner except that the upper clad pattern marker 45 was formed in the center of the gap of the core pattern marker 35 in the (Y direction) × 2 locations.

[Formation of inclined surface]
A dicing saw (DAC552, stock) is formed to a depth of 7 μm from the surface of the lower cladding layer so as to cross the measurement marker 50 and the core pattern 30 embedded in the cladding layer from the upper cladding layer 40 forming surface side of the obtained optical waveguide. 45 ° inclined surfaces 70A and 70B opposed to each other using a disco company).

[Measurement of thickness]
The obtained optical waveguide was viewed from the direction perpendicular to each layer formation surface on the upper clad layer side, and when the measurement marker 50 was viewed by transmitted illumination of a white halogen lamp, the contrast became clear as shown in FIG. Was good. Therefore, the thickness of the core pattern marker 35 and the upper clad pattern marker 45 formed on the core pattern marker 35 was measured using the step 47. As a result, the thickness of the core pattern marker 35 was 50.0 μm, and the thickness of the upper clad pattern marker 45 was 16.2 μm. When the thickness of the core pattern 30 and the thickness of the core cladding upper cladding pattern 42 in the vicinity thereof were also measured, a correlation within ± 0.3 μm could be confirmed.

[Visibility from other directions]
When the obtained optical waveguide is viewed from the vertical direction of each layer formation surface from the vertical direction of each layer formation surface when viewed from the vertical direction of each layer formation surface by epi-illumination of a white halogen lamp from the vertical direction of each layer formation surface on the lower cladding layer side, it is slightly inferior The thing was good.

[Visibility from other directions]
The obtained optical waveguide was viewed from the vertical direction of each layer formation surface on the lower clad layer side by the transmitted illumination of a white halogen lamp, and when the measurement marker was viewed from the vertical direction of each layer formation surface, the same as when viewed from the upper clad layer side It was very good.

Example 5
In Example 4, a metal mask having an opening of 800 μm square was aligned with a thickness measurement marker, and Au was used as a light-shielding layer by using an evaporation device (“RE-0025” manufactured by First Giken Co., Ltd.) as a light shielding layer. A process of 5 μm vapor deposition was performed.

[Measurement of thickness]
When the obtained optical waveguide was viewed from the vertical direction of each layer formation surface from the vertical direction of each layer formation surface by the epi-illumination of a white halogen lamp from the vertical direction of each layer formation surface on the upper clad layer side, it was good. Therefore, the thickness of the core clad marker 35 and the upper clad pattern 403 formed on the core pattern marker 303 is set using the step 47 between the slanted surface of the core pattern marker 35 and the slanted surface of the upper clad pattern marker 45. It was measured. As a result, the thickness of the core pattern marker was 50.0 μm, and the thickness of the upper cladding pattern marker 403 was 16.2 μm. When the thickness of the core pattern 302 and the thickness of the upper clad pattern 402 in the vicinity thereof were measured together, a correlation within ± 0.3 μm could be confirmed.

Comparative Example 1
In Example 1, an optical waveguide was manufactured by the same method except that the upper clad pattern marker 403 was changed to φ600 μm, and the core pattern marker 303 completely embedded in the upper clad pattern marker 403 was formed.
[Measurement of misalignment]
When the obtained optical waveguide was viewed from the upper clad layer side by epi-illumination with a white halogen lamp from the direction perpendicular to each layer formation surface, the outline of the core pattern marker 303 was unclear and could not be measured. Similar results were obtained even with transmitted illumination.

Comparative Example 2
In Example 4, after forming the optical waveguide, an inclined surface is not formed, and a blade whose angle with respect to each layer forming surface is 90 ° is used by using the above-mentioned dicing saw (“DAC552” manufactured by DISCO Corporation). Then, the substrate was cut to reveal the cross section of the optical waveguide. As a result of observing the obtained substrate from the cross-sectional direction and measuring the thicknesses of the core layer and the upper clad layer, the same results as in Example 4 were obtained. However, holding the substrate during measurement was complicated and workability was poor. It was.

  An optical waveguide according to the present invention includes an optical waveguide capable of easily measuring the deviation between the core pattern of the optical waveguide and the upper cladding layer, an optical waveguide capable of easily measuring the thickness of the core pattern of the optical waveguide and the upper cladding layer, and Therefore, it can be applied to various fields such as various optical devices and optical interconnections.

DESCRIPTION OF SYMBOLS 10 Optical waveguide 11 Board | substrate 20 Lower clad layer 21 Lower clad pattern 30 Core pattern 35 Core pattern marker 36 Overhang | projection part 40 Upper clad layer 41 Upper clad pattern 45 Upper clad pattern marker 47 Step 50 Measurement marker 60 Electric wiring 65 Electric wiring marker 70 Optical path conversion mirror 70A, 70B Inclined surface

Claims (15)

An optical waveguide comprising a lower cladding layer, and a core pattern and an upper cladding layer provided on the lower cladding layer,
An optical waveguide further comprising a core pattern marker that is partly embedded in an upper clad pattern obtained by patterning the upper clad layer and that part of the upper clad layer extends from the upper clad pattern.   2. The optical waveguide according to claim 1, wherein an overhanging portion protruding from the upper clad pattern of the core pattern marker is disposed so as to face when viewed along a predetermined direction.   The optical waveguide according to claim 2, wherein the protruding portions are arranged so as to face each other even when viewed along a direction different from the predetermined direction. The upper clad pattern comprises an upper clad pattern marker provided separately from the upper clad pattern in which the core pattern is buried,
4. The optical waveguide according to claim 1, wherein a part of the core pattern marker is embedded in the upper clad pattern marker and a part of the core pattern marker protrudes from the upper clad pattern marker.   The optical waveguide according to claim 4, wherein the core pattern marker is formed in a ring shape or a frame shape, and the upper clad pattern marker is filled therein.   The optical waveguide according to claim 1, wherein an outline of the core pattern marker is similar to an outline of the upper clad pattern.   When viewed in the thickness direction, at least one of a lower clad pattern marker and an electrical wiring marker is provided, at least a part of which is disposed on the outer peripheral side of the core pattern marker, and the lower clad pattern marker is provided on the lower clad layer The optical waveguide according to claim 1, wherein the optical waveguide is patterned.   An inclined surface that is continuous with the protruding portion and the upper cladding pattern is formed so as to straddle the step at the boundary between the protruding portion of the core pattern marker protruding from the upper cladding pattern and the upper cladding pattern. The optical waveguide according to claim 1.   The optical waveguide according to claim 8, wherein the inclined surface provided in the projecting portion and the inclined surface provided in the core pattern marker are on the same plane.   The optical waveguide according to claim 8, wherein the inclined surface is formed by cutting. An optical path conversion mirror having an inclined surface is provided in the core pattern,
11. The optical waveguide according to claim 8, wherein the inclined surface of the core pattern is on the same plane as the inclined surface provided on the projecting portion and the inclined surface provided on the core pattern marker. The optical waveguide according to claim 1, wherein the core pattern and the core pattern marker are formed by photolithography. An inspection method for an optical waveguide according to claim 1,
A method for inspecting an optical waveguide, wherein the misalignment between the core pattern marker and the upper cladding pattern is measured, and the measured value is used as the misalignment between the core pattern and the upper cladding layer. The optical waveguide inspection method according to claim 8, wherein:
A method for inspecting an optical waveguide, comprising: observing the optical waveguide in a thickness direction; measuring a length of an inclined surface of the projecting portion; and measuring a thickness of the core pattern from the length.   The optical waveguide inspection method according to claim 13 or 14, wherein the optical waveguide is observed using epi-illumination and / or transmitted illumination.

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