JP2004078084A - Method for manufacturing optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical waveguide, which easily forms a stable core pattern, forms an optical path conversion mirror in a process that continues a manufacturing process of a core pattern and manufactures a stable polymer optical waveguide at a low cost. <P>SOLUTION: In the manufacturing of an optical waveguide which forms a core pattern 1A in a pattern-shaped recessed part of a substrate 10, forms a state clad 2A overlapped on two surfaces of cladding material of another substrate 20 and forms a clad 3A over the entire surface of the other substrate, surface treatment that improves the affinity of the core material on the surface of a substrate having the pattern-shaped recessed part before filling the core material only in the pattern-shaped recessed part of the substrate. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an optical waveguide used for optical interconnection and the like.
[0002]
[Prior art]
In recent years, the advance of optical communication technology has demonstrated the superiority of light. Also, with the speeding up of signals of LSIs and the like, research and development of technology for replacing electric signals with optical signals are being advanced. An optical waveguide is expected as the transmission medium.
[0003]
In recent years, polymer optical waveguides that have been developed can be formed in a large area, and are being applied to optical interconnections on the order of 1 cm to 1 m. Further, an optical path conversion mirror is formed on an optical waveguide, and an optical component is mounted on the surface of the optical waveguide layer.
As a method for manufacturing a polymer optical waveguide, a method using dry etching as shown in FIG. 10 and a method using pattern exposure and development as shown in FIG. 11 are generally used. As a method of forming the optical path conversion mirror, as shown in FIG. 12, machining using a dicing saw is common.
[0004]
However, performing the manufacturing of the optical waveguide and the processing of the optical path conversion mirror in separate steps complicates the manufacturing process and increases the cost. Therefore, as a method of manufacturing the optical waveguide and the optical path conversion mirror in a continuous process, for example, there is a method using a mold as shown in FIG. This method is a method disclosed in Japanese Patent Application Laid-Open No. 2001-154049. Here, first, the core material 1 is applied and cured on the substrate 50 having the concave portion, and then the core material 1 other than the concave portion is removed. Then, the core 1A is formed, then the clad 2A is formed on the entire surface, and the whole is transferred to another substrate 20, and then the optical path conversion mirror 4 and the clad 3A are formed.
[0005]
However, in this method, after forming the cured core 1A on the entire surface of the substrate 50 having the concave portion, it is necessary to perform a long-time etching process to remove the core 1A other than the concave portion, thereby increasing the cost.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the situation of the related art, and in manufacturing a polymer optical waveguide, a stable core pattern can be easily formed. It is an object of the present invention to provide a method for manufacturing an optical waveguide that can be performed in a step that is continuous with the steps, that is, that can manufacture a stable and stable polymer optical waveguide at low cost.
[0007]
[Means for Solving the Problems]
The present invention relates to a method for manufacturing an optical waveguide in which a core pattern is formed using a mold, wherein the surface of the mold is subjected to a surface treatment for increasing the affinity of a core material or a clad material in advance. Is a manufacturing method.
[0008]
Further, the present invention provides the method for manufacturing an optical waveguide according to the above invention, wherein the mold has a substrate having a pattern-shaped concave portion,
1) a step of filling the core only into the pattern-shaped concave portions of the substrate having the pattern-shaped concave portions and superimposing the core on a clad surface of another substrate on which the clad is applied in advance;
2) peeling the substrate having the pattern-shaped concave portion and transferring the core pattern onto the clad;
In the method of manufacturing an optical waveguide having at least a pattern recess, before filling the core only into the pattern recess of the substrate having the pattern recess, a surface treatment for increasing the affinity of the core material is performed on the surface of the substrate having the pattern recess. This is a method for manufacturing an optical waveguide.
[0009]
Further, the present invention is the method for manufacturing an optical waveguide according to the above invention, wherein at least a surface of the mold is a silicone resin.
[0010]
Further, the present invention is the method for manufacturing an optical waveguide according to the above invention, wherein the core material and / or the clad material is an epoxy resin.
[0011]
Also, the present invention provides the method of manufacturing an optical waveguide according to the above invention, wherein the method of filling a core material only in the pattern-shaped concave portion of the substrate having the patterned concave portion is performed after the core material is applied to the substrate having the patterned concave portion. And a method of scraping an excess core material with a spatula.
[0012]
Further, the present invention provides the method of manufacturing an optical waveguide according to the above invention, wherein the core material is filled only in the pattern-shaped concave portion of the substrate having the pattern-shaped concave portion, and the core material is overlapped with a clad surface of another substrate on which the clad is previously applied. However, there is provided a method of manufacturing an optical waveguide, which comprises inserting a core material between a substrate having a pattern-shaped concave portion and another substrate to which cladding is applied in advance.
[0013]
Further, the present invention is the method for manufacturing an optical waveguide according to the above invention, wherein the surface treatment is an oxygen plasma treatment.
[0014]
Further, the present invention is the method for manufacturing an optical waveguide according to the above invention, wherein the surface treatment is a surface treatment for reducing a contact angle of a core material to a mold to 45 ° or less. .
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method for manufacturing an optical waveguide according to the present invention will be described based on its embodiments.
FIG. 1 is an explanatory view showing a cross section of one embodiment of a method for manufacturing an optical waveguide according to the present invention. As shown in FIG. 1A, first, a substrate 10 having a pattern-shaped concave portion is prepared. The substrate 10 having the pattern concave portion has a role of a mold when forming the optical waveguide. In addition to the core pattern of the optical waveguide, a portion corresponding to a mirror and an optical circuit such as a diffraction grating, a branch circuit, and an arrayed waveguide diffraction grating can be incorporated in the pattern-shaped concave portion.
[0016]
As a material of the substrate 10 having the pattern-shaped concave portions, a silicone resin is preferable. This is because the silicone resin is flexible, so that when the core pattern is transferred to another substrate with a clad, it is easy to stick and peel off, and the core pattern is not easily damaged.
The substrate 10 having the pattern-shaped concave portions may be entirely made of silicone resin, and at least the surface having the pattern-shaped concave portions is preferably made of silicone resin.
[0017]
As shown in FIG. 1B, a surface treatment is performed on the substrate 10 having the pattern-shaped concave portions. By the surface treatment, the affinity of the substrate 10 having the pattern-shaped concave portion for the core material 1 can be increased. Specifically, the core material 1 can be stably embedded by setting the contact angle of the core material 1 to the substrate 10 having the pattern-shaped concave portion to 45 ° or less. As a surface treatment method, an oxygen plasma treatment is preferable.
[0018]
Next, as shown in FIGS. 1C to 1D, the core material 1 is filled only in the pattern-shaped concave portions. As the core material 1, for example, an epoxy resin, in particular, an ultraviolet curable epoxy resin is suitable.
As a filling method, a method of scraping an excess core material using a blade after the entire surface is applied, for example, a method of scraping using a spatula 8 as a blade is possible. Then, the core material 1 is cured by irradiation with ultraviolet rays to form a core pattern 1A.
[0019]
Here, as shown in FIG. 1E, another substrate 20 is prepared, and the cladding material 2 is applied to the entire surface. Then, as shown in FIG. 1 (f), the substrate 10 on which the core pattern 1A is formed and another substrate 20 on which the clad material 2 is applied are superimposed, and the clad material 2 is irradiated with ultraviolet light in the superimposed state. After curing, the clad 2A is formed, the substrate 10 is peeled off, and the core pattern 1A is transferred to another substrate 20 side.
As the clad material 2, for example, an ultraviolet curable epoxy resin is preferable. Further, the method of curing the core material 1 and the clad material 2 is not limited to curing by irradiation with ultraviolet rays.
[0020]
As shown in FIG. 1 (g), the metal mirror 4 is formed by depositing a metal on the inclined surface of the core pattern 1A. In order to attach metal only to the inclined surface, a mask evaporation method or a lift-off method can be used. The optical path conversion mirror not only converts the optical path in a direction perpendicular to the optical waveguide layer as shown in FIG. 4 but also converts the optical path to an arbitrary angle in the plane of the optical waveguide layer as shown in FIG. It can also be used to
[0021]
Next, as shown in FIG. 1 (h), the clad material 3 is applied to the entire surface and cured to form the clad 3A, whereby the single-layer optical waveguide 5 is completed. Alternatively, air may be used instead of the clad without providing the clad 3A.
As shown in FIG. 2, before the clad material 3 is cured, the multilayer optical waveguide 6 is formed by forming and transferring a core pattern 1 ′ on a substrate 10 ′ having another pattern-shaped concave portion. You can also. In FIG. 2, (h) shows (h) in FIG.
[0022]
In forming the multilayer optical waveguide 6, or in order to transfer the optical waveguide 5 shown in FIG. 1 and the multilayer optical waveguide 6 shown in FIG. 2 to another substrate, for example, an electric wiring substrate (not shown). It is desirable to provide an alignment mark (not shown) on another substrate 20 or in the cladding 2A.
When the optical waveguide 5 or the multilayer optical waveguide 6 is used as a film, a release layer (not shown) is provided between the separate substrate 20 and the clad material 2, and after the optical waveguide is manufactured, it is peeled off. Is desirable. It is desirable that the separate substrate 20 and the release layer or the substrate 10 having the pattern-shaped concave portions are transparent to ultraviolet rays.
[0023]
In manufacturing the substrate 10 having the pattern-shaped concave portions, as shown in FIGS. 6C to 6E, a method of preparing the substrate 30 having the pattern-shaped convex portions and molding the substrate 30 with a silicone resin 34 or the like is used. Can be.
For example, as shown in FIG. 6A, the substrate 30 having the pattern-shaped convex portions is formed by applying a photoresist or an ultraviolet curable epoxy resin 32 on a substrate 31, pattern-exposing the substrate 31 to an optical waveguide shape, and developing it. Then, a pattern having a rectangular cross-sectional shape is formed, and then, as shown in FIG.
As the laser beam 33, an excimer laser is preferable.
[0024]
The aspect ratio (height / width) of the core pattern is usually about 1. In this case, when viewed from above, the mirror that changes the optical path in the direction perpendicular to the optical waveguide layer has a substantially square shape when viewed from above, and is substantially the same in the XY directions required for component alignment. However, there is no problem in waveguide even if the aspect ratio is not 1. Actually, waveguiding was confirmed at an aspect ratio of 0.27 to 2.
[0025]
In addition, instead of filling the core material 1 only in the pattern-shaped concave portions and curing and curing the core material 1 on the separate substrate 20 with the clad material, as shown in FIG. It is also possible to manufacture a waveguide by inserting 1. That is, first, a substrate 10 having a pattern-shaped concave portion is prepared (FIG. 14A), and a surface treatment is performed (FIG. 14B). Next, another substrate 20 with a clad 2A is prepared (FIG. 14C), and the core material 1 is inserted between the substrate 10 and the substrate 10 having the pattern-shaped concave portion (FIG. 14D).
[0026]
The core material 1 is cured into a core pattern 1A by a method of irradiating ultraviolet rays from one or both of the other substrate side and the substrate having the pattern concave portion (FIG. 14 (e)), and the substrate 10 is peeled off to form a core pattern. 1A is transferred to another substrate 20 side. Then, metal is deposited on the inclined surface of the core pattern 1A to form a metal mirror 4 (FIG. 14F). Usually, it is covered with the clad 3 (FIG. 14 (g)). Also in this case, a stable core can be formed by the surface treatment.
[0027]
Further, it goes without saying that not only a concave mold (a substrate having a pattern-shaped concave portion) but also a convex mold (a substrate 11 having a pattern-shaped convex portion) can be used. For example, as shown in FIG. 15, a clad 2A having a pattern-shaped concave portion is formed by using a surface-treated convex mold 11, a metal mirror 4 is formed, a core 1A is embedded, and a waveguide is formed by covering with a clad 3A. can do.
[0028]
【Example】
Hereinafter, a method for manufacturing an optical waveguide according to the present invention will be described in detail with reference to examples.
<Example 1>
[Preparation of substrate having patterned concave portion]
This will be described with reference to FIG. First, a plurality of optical waveguide convex patterns having a height of 40 μm and a width of 20 μm to 150 μm are formed as a resist pattern 32 by applying, baking, exposing, and developing a photoresist for a thick film on a substrate 31 (glass). (FIG. 6A).
[0029]
Next, a portion serving as an optical path conversion mirror is processed by obliquely irradiating a KrF excimer laser as a laser beam 33 (FIG. 6B) to obtain a substrate 30 having a pattern-shaped convex portion (FIG. 6C). ).
Next, the substrate 10 having a pattern-shaped concave portion was manufactured by molding using a liquid silicone resin 34 (FIGS. 6D to 6E).
[0030]
[Production of Optical Waveguide 1]
This will be described with reference to FIGS. First, a substrate 10 (silicone resin) having a patterned concave portion was prepared (FIG. 1A). Next, oxygen plasma treatment was performed on the substrate having the pattern-shaped concave portions (FIG. 1B). The used apparatus is OPM-SQ600 (model number) manufactured by Tokyo Ohka Kogyo Co., Ltd. The oxygen flow rate was 100 SCCM, the pressure was 60 Pa, the plasma power was 100 W, and the time was 2 minutes.
Then, an ultraviolet curable epoxy resin was applied as the core material 1 on the entire surface, and the spatula 8 was used to scrape off the core material 1 except for the concave portions. By irradiating the entire surface with ultraviolet rays, the core material 1 was cured to form a core pattern 1A (FIGS. 1C to 1D).
[0031]
As for the formed core pattern 1A, a continuous core pattern 1A could be formed without any problem for all types having a core width of 20 μm to 150 μm (FIG. 3).
[0032]
On the other hand, another substrate 20 (glass) was prepared, and an ultraviolet curable epoxy resin was spin-coated as a cladding material 2 on the entire surface (FIG. 1 (e)).
Here, by irradiating ultraviolet rays from another substrate side in a state where both are overlapped, the core pattern 1A and the clad material 2 are brought into close contact with each other, and the clad material 2 is cured to form a clad 2A (FIG. 1 (f)). .
[0033]
After the substrate 10 having the pattern-shaped concave portions was peeled off, metal Al was vapor-deposited on the inclined surface by mask vapor deposition to form a metal mirror 4. Further, an ultraviolet-curable epoxy resin was applied as a cladding material 3 on the entire surface and irradiated with ultraviolet rays to complete the optical waveguide 5.
[0034]
<Example 2>
[Production of Optical Waveguide 2]
The contact angle of the core material on the silicone was measured by changing the conditions of the oxygen plasma treatment at a constant oxygen flow rate of 100 SCCM and a constant pressure of 60 Pa, a plasma power of 20 W to 400 W, and a time of 1 second to 10 minutes.
As shown in FIG. 7, it was confirmed that the contact angle of the untreated silicone was about 60 °, but changed to about 40 ° to 25 ° by the oxygen plasma treatment. In each of the cases where the oxygen plasma treatment shown in FIG. 7 was performed, an optical waveguide was produced in the same manner as in Example 1.
[0035]
<Example 3>
[Production of Optical Waveguide 4]
This will be described with reference to FIG. First, in the same manner as in Example 1, a substrate 10 having a patterned concave portion was prepared (FIG. 14A), and the substrate having the patterned concave portion was subjected to oxygen plasma treatment (FIG. 14B).
[0036]
On the other hand, another substrate 20 (glass) was prepared, and the entire surface was spin-coated with an ultraviolet-curing epoxy resin as the cladding material 2 and irradiated with ultraviolet rays to form a cladding 2A (FIG. 14C).
[0037]
Then, the core material 1 was sandwiched between the substrate 10 having the pattern-shaped concave portion and the substrate 20 having the clad 2A, and the substrate 20 was irradiated with ultraviolet rays to form the core pattern 1A (FIG. 14 (d)). )-(E)).
[0038]
After peeling off the substrate 10 having the pattern-shaped concave portions, metal Al was vapor-deposited on the inclined surface by mask vapor deposition to form the metal mirror 4 (FIG. 14F). Further, an ultraviolet curable epoxy resin was applied as the clad material 3 on the entire surface and cured by ultraviolet light to complete the optical waveguide 5 (FIG. 14 (g)).
[0039]
<Example 4>
[Production of Optical Waveguide 6]
This will be described with reference to FIG. First, a (silicone) substrate 11 having a pattern-shaped convex portion was prepared by a method similar to that of Example 1 (FIG. 15A), and the substrate 11 having the pattern-shaped convex portion was subjected to oxygen plasma treatment (FIG. 15A). 15 (b)).
[0040]
On the other hand, another substrate 20 (glass) is prepared, and the entire surface is spin-coated with an ultraviolet-curable epoxy resin as the cladding material 2 (FIG. 15C), and is superposed on the substrate having the pattern-shaped convex portions and irradiated with ultraviolet rays. To form a clad 2A (FIG. 15D).
[0041]
Then, the substrate 11 having the pattern-shaped convex portions was peeled off (FIG. 15E), and metal Al was vapor-deposited on the inclined surface by mask vapor deposition to form the metal mirror 4 (FIG. 15F). Further, an ultraviolet curable epoxy resin was applied on the entire surface as the core material 1, and the core material 1 other than the concave portions was scraped off with the spatula 8. By irradiating the entire surface with ultraviolet rays, the core material 1 was cured to obtain a core pattern 1A (FIGS. 15 (g) to (h)).
[0042]
Finally, an ultraviolet curable epoxy resin was applied as the clad material 3 on the entire surface and cured by ultraviolet light to complete the optical waveguide 5 (FIG. 15 (i)).
[0043]
<Comparative Example 1>
[Production of Optical Waveguide 3]
This will be described with reference to FIGS. First, a substrate 10 (silicone resin) having a patterned recess was prepared according to [Production of a substrate having a patterned recess] in Example 1 (FIG. 8A). Next, an ultraviolet curable epoxy resin was applied as the core material 1 over the entire surface without performing any special surface treatment, and the spatula 8 was used to scrape the core material 1 other than the concave portions. By irradiating the entire surface with ultraviolet rays, the core 1 was cured to obtain a core pattern 1A (FIGS. 8B to 8C).
[0044]
At this time, a core pattern with a core width of 100 μm or more could be formed without any problem, but with a core pattern with a core width of 50 μm or less, the core 1A was likely to be interrupted (FIG. 9), and it was difficult to form a continuous waveguide. .
[0045]
<Comparative Example 2>
[Production of Optical Waveguide 5]
A waveguide was produced in the same manner as in Example 3 except that no special surface treatment was performed. In that case, the core material 1 is sandwiched between the substrate 10 having the pattern-shaped concave portion and the substrate 20 with the clad 2A (FIG. 14D), and then the substrate 20 is irradiated with ultraviolet rays (FIG. 14E). Until)), the substrate 10 having the pattern-shaped concave portion was easily peeled off, and a clean core pattern 1A could not be formed.
[0046]
<Comparative Example 3>
[Production of Optical Waveguide 7]
A waveguide was produced in the same manner as in Example 4, except that no special surface treatment was performed. In this case, when the substrate 20 with the clad material 2 was superimposed on the substrate 11 having the pattern-shaped convex portions, the clad material 2 did not spread well, and a clean clad 2A could not be formed.
[0047]
【The invention's effect】
The present invention performs a surface treatment that enhances the affinity of the core material on the surface of the substrate having the patterned recess before filling the core with only the patterned recess of the substrate having the patterned recess. Can be easily formed. In addition, since the inclined surface serving as the optical path conversion mirror is provided in the core pattern, it is not necessary to form the inclined surface again, and metal deposition on the inclined surface can be performed in a process continuous with the core pattern manufacturing process.
That is, a method for manufacturing an optical waveguide capable of manufacturing a stable polymer optical waveguide at low cost is provided.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a cross section of one embodiment of a method for manufacturing an optical waveguide of the present invention.
FIG. 2 is an explanatory diagram showing a cross section showing an example of a method for manufacturing a multilayer optical waveguide of the present invention.
FIG. 3 is a sectional view of a core pattern according to the first embodiment.
FIG. 4 is a perspective view showing an example of the optical waveguide of the present invention.
FIG. 5 is a perspective view showing another example of the optical waveguide of the present invention.
FIG. 6 is a cross-sectional view illustrating an example of a method for manufacturing a substrate having a patterned concave portion according to the present invention.
FIG. 7 is an explanatory diagram showing a change in a contact angle due to oxygen plasma processing.
FIG. 8 is a cross-sectional view illustrating a method for manufacturing an optical waveguide in Comparative Example 1.
FIG. 9 is a sectional view of a core pattern in Comparative Example 1.
FIG. 10 is a cross-sectional view illustrating an example of a conventional method for manufacturing an optical waveguide.
FIG. 11 is a cross-sectional view showing another example of a conventional method for manufacturing an optical waveguide.
FIG. 12 is a cross-sectional view illustrating an example of a conventional method for manufacturing an optical path conversion mirror.
FIG. 13 is a cross-sectional view illustrating an example of a conventional manufacturing method for continuously manufacturing an optical waveguide and an optical path conversion mirror.
FIG. 14 is a sectional view illustrating the method for manufacturing the optical waveguide in the third embodiment.
FIG. 15 is a cross-sectional view illustrating the method for manufacturing the optical waveguide in the fourth embodiment.
[Explanation of symbols]
1, 1 '... core material 1A, 1'A ... core pattern 2, 3 ... clad material 2A, 3A, 3'A ... clad 4, 4', 4 "... metal mirror 5 ... optical waveguide 6 ... multilayer optical waveguide 7 ... optical path 8 ... spatula 10, 10 '... substrate 11 having a pattern-shaped concave portion ... substrate 20 having a pattern-shaped convex portion ... another substrate 30 ... substrate 31, 50 having a pattern-shaped convex portion ... substrate 32 ... photoresist or epoxy resin 33 laser light 34 silicone resin 51 silicon-containing resist or metal mask 52 reactive ion 53 ultraviolet exposure 54 dicing blade 55 total reflection mirror 56 adhesive

Claims (8)

What is claimed is: 1. A method for manufacturing an optical waveguide, comprising forming a core pattern using a mold, wherein the surface of the mold is preliminarily subjected to a surface treatment for increasing the affinity of a core material or a clad material. The mold is a substrate having a patterned recess,
1) a step of filling the core only into the pattern-shaped concave portions of the substrate having the pattern-shaped concave portions and superimposing the core on a clad surface of another substrate on which the clad is applied in advance;
2) peeling the substrate having the pattern-shaped concave portion and transferring the core pattern onto the clad;
In the method of manufacturing an optical waveguide having at least a pattern recess, a surface treatment is performed to enhance the affinity of the core material on the surface of the substrate having the pattern recess before the core is filled only in the pattern recess of the substrate having the pattern recess. 2. The method for manufacturing an optical waveguide according to claim 1, wherein: 3. The method according to claim 1, wherein at least a surface of the mold is a silicone resin. 4. The method according to claim 1, wherein the core material and / or the clad material is an epoxy resin. The method of filling the core material only into the pattern-shaped concave portions of the substrate having the pattern-shaped concave portions is a method of applying the core material to the substrate having the pattern-shaped concave portions, and then scraping off the excess core material with a spatula. The method for manufacturing an optical waveguide according to claim 2, 3, or 4. The step of filling the core material only in the pattern-shaped concave portions of the substrate having the pattern-shaped concave portions and superimposing the core material on the clad surface of another substrate coated with the clad in advance is performed separately from the substrate having the patterned concave portions and the clad previously coated. 5. The method for manufacturing an optical waveguide according to claim 2, wherein a core material is sandwiched between the substrate and the substrate. 7. The method according to claim 1, wherein the surface treatment is an oxygen plasma treatment. The said surface treatment is a surface treatment which makes the contact angle of a core material to a type | mold 45 degrees or less, The Claim 1, Claim 2, Claim 3, Claim 4, Claim 5, Claim 6 characterized by the above-mentioned. A method of manufacturing an optical waveguide according to claim 7.

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