JP3979225B2 - Manufacturing method of optical waveguide - Google Patents

Description

[0001]
BACKGROUND 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 superiority of light has been demonstrated by the progress of optical communication technology. In addition, with the speeding up of signals of LSIs and the like, research and development of techniques for replacing electrical signals with optical signals are being carried out. An optical waveguide is expected as the transmission medium.
[0003]
In recent years, polymer optical waveguides being developed can be formed in a large area, and are applied to optical interconnections on the order of 1 cm to 1 m. In addition, an optical component is mounted on the surface of an optical waveguide layer by forming an optical path conversion mirror on the optical waveguide.
As a method for producing 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 common. Further, as a method for forming the optical path conversion mirror, as shown in FIG. 12, machining by a dicing saw is generally used.
[0004]
However, if the manufacturing of the optical waveguide and the processing of the optical path conversion mirror are performed in separate processes, the manufacturing process is complicated and expensive. 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 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 recesses, and then the core material 1 other than the recesses is removed. Then, the core 1A is formed, and then the clad 2A is formed on the entire surface. After the whole is transferred to another substrate 20, the optical path conversion mirror 4 and the clad 3A are formed.
[0005]
However, this method is a method in which, after forming the hardened core 1A on the entire surface of the substrate 50 having the recesses, a long etching process is required to remove the cores 1A other than the recesses, and the cost is increased.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of such a state of the art, and in the production of a polymer optical waveguide, a stable core pattern can be easily formed, and an optical path conversion mirror can be produced as a core pattern. It is an object of the present invention to provide a method of manufacturing an optical waveguide that can be performed in a process that is continuous with the process, that is, capable of manufacturing a stable polymer optical waveguide at low cost.
[0007]
[Means for Solving the Problems]
The present invention relates to a method of manufacturing an optical waveguide in which a core pattern is formed using a mold, and the surface of the mold is subjected to a surface treatment that enhances the affinity of the core material or the clad material in advance. It is a manufacturing method.
[0008]
Further, the present invention is a method of manufacturing an optical waveguide according to the above invention, wherein the mold has a pattern-shaped recess,
1) A step of filling a core only in a pattern-like recess of a substrate having a pattern-like recess and superimposing it on a clad surface of another substrate on which a clad has been previously applied;
2) peeling the substrate having the pattern-like recesses, and transferring the core pattern onto the clad;
In the method of manufacturing an optical waveguide having at least, a surface treatment for increasing the affinity of the core material is performed on the surface of the substrate having the patterned recess before filling the core only in the patterned recess of the substrate having the patterned recess. This is a method for manufacturing an optical waveguide.
[0009]
The present invention also provides the method for manufacturing an optical waveguide according to the above invention, wherein at least the surface of the mold is made of a silicone resin.
[0010]
The present invention is also 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]
According to the present invention, in the method of manufacturing an optical waveguide according to the above invention, the method of filling the core material only in the pattern-like recess of the substrate having the pattern-like recess is after the core material is applied to the substrate having the pattern-like recess. A method of manufacturing an optical waveguide, characterized by being a method of scraping off an excess core material with a spatula.
[0012]
Further, the present invention provides a method of manufacturing an optical waveguide according to the above invention, wherein only the pattern-shaped recess of the substrate having the pattern-shaped recess is filled with a core material and overlapped with a clad surface of another substrate on which a clad has been applied in advance. However, this is a method of manufacturing an optical waveguide, which is a method of sandwiching a core material between a substrate having a patterned concave portion and another substrate on which a clad has been previously applied.
[0013]
The present invention also provides the method for manufacturing an optical waveguide according to the above-described 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-described invention, wherein the surface treatment is a surface treatment for setting a contact angle of the core material to the mold to 45 ° or less. .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Below, the manufacturing method of the optical waveguide by this invention is demonstrated based on the embodiment.
FIG. 1 is a cross-sectional view illustrating an 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-like recess is prepared. The substrate 10 having the pattern-like recess has a role of a mold when forming an optical waveguide. Not only the core pattern of the optical waveguide but also a portion corresponding to a mirror, or an optical circuit such as a diffraction grating, a branch circuit, or an arrayed waveguide diffraction grating can be incorporated in the pattern-shaped recess.
[0016]
Silicone resin is suitable as the material for the substrate 10 having the pattern-like recesses. This is because the silicone resin is flexible, so that the core pattern is easily bonded and peeled off when it is transferred to another clad substrate, and the core pattern is not easily damaged.
The substrate 10 having a pattern-like recess may be entirely made of a silicone resin, and at least the surface having the pattern-like recess is preferably a silicone resin.
[0017]
As shown in FIG. 1B, the surface treatment is performed on the substrate 10 having the pattern-like recesses. By the surface treatment, the affinity of the substrate 10 having the pattern-like recesses 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-like recesses to be 45 ° or less. As the surface treatment method, oxygen plasma treatment is suitable.
[0018]
Next, as shown in FIGS. 1C to 1D, the core material 1 is filled only in the pattern-like recesses. As the core material 1, for example, an epoxy resin, particularly an ultraviolet curable epoxy resin is suitable.
As a filling method, a method of scraping off an excess core material using a blade after the entire surface coating, for example, a method of scraping the spatula 8 as a blade is possible. And the core material 1 is hardened by ultraviolet irradiation, and it is set as the core pattern 1A.
[0019]
Here, as shown in FIG. 1E, another substrate 20 is prepared, and the clad 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 coated with the clad material 2 are superposed, and the clad material 2 is irradiated by irradiating ultraviolet rays in the superposed state. Curing is performed to form a clad 2A, and the substrate 10 is peeled off to transfer the core pattern 1A to the other substrate 20 side.
As the clad material 2, for example, an ultraviolet curable epoxy resin is suitable. Further, the curing method of the core material 1 and the cladding material 2 is not limited to curing by ultraviolet irradiation.
[0020]
As shown in FIG. 1G, the optical path conversion mirror is formed as a metal mirror 4 by depositing metal on the inclined surface of the core pattern 1A. In order to attach metal only to the inclined surface, a mask vapor deposition method or a lift-off method can be used. The optical path conversion mirror not only converts the optical path in the direction perpendicular to the optical waveguide layer as shown in FIG. 4, but also converts the optical path to an arbitrary angle within the plane of the optical waveguide layer as shown in FIG. Can also be used.
[0021]
Next, as shown in FIG. 1 (h), a clad material 3 is applied to the entire surface and cured to form a clad 3A, whereby a single-layer optical waveguide 5 is completed. Alternatively, air can be substituted for the clad without providing the clad 3A.
Further, as shown in FIG. 2, before the clad material 3 is cured, the multilayer optical waveguide 6 is formed by forming and transferring the core pattern 1 ′ to the substrate 10 ′ having another pattern-like recess. You can also. In FIG. 2, (h) shows (h) in FIG.
[0022]
When forming the multilayer optical waveguide 6, or for transferring the optical waveguide 5 shown in FIG. 1 and the multilayer optical waveguide 6 shown in FIG. 2 to still another substrate, for example, an electrical wiring substrate (not shown). It is desirable to provide an alignment mark (not shown) on the separate substrate 20 or in the clad 2A.
Further, 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 the film is peeled off after the optical waveguide is manufactured. It is desirable to make it. It is desirable that the separate substrate 20 and the release layer or the substrate 10 having the pattern-like recess be transparent to ultraviolet rays.
[0023]
As shown in FIGS. 6C to 6E, a method of preparing a substrate 30 having a pattern-shaped convex portion and making a mold with a silicone resin 34 or the like is used for manufacturing the substrate 10 having the pattern-shaped concave portion. Can do.
For example, as shown in FIG. 6A, the substrate 30 having the pattern-shaped convex portions is coated with a photoresist or an ultraviolet curable epoxy resin 32 on the substrate 31, and is subjected to pattern exposure and development into an optical waveguide shape. Then, a pattern with a rectangular cross-sectional shape can be formed, and then, as shown in FIG.
As the laser beam 33, an excimer laser is suitable.
[0024]
The aspect ratio (height / width) of the core pattern is usually about 1. In this case, the mirror that changes the optical path in the direction perpendicular to the optical waveguide layer is substantially square when viewed from above, and is approximately the same in the XY direction of the component alignment request. However, even if the aspect ratio is not 1, there is no problem with wave guiding. Actually, the waveguide is confirmed at an aspect ratio of 0.27 to 2.
[0025]
Further, instead of filling the core material 1 only in the pattern-like recesses and overlapping the other substrate 20 with the clad material after curing, the core material is interposed between the substrate 10 having the pattern-like recesses and the other substrate 20 with the clad as shown in FIG. It is also possible to produce a waveguide by sandwiching 1. That is, first, a substrate 10 having a patterned concave portion is prepared (FIG. 14A) and surface treatment is performed (FIG. 14B). Next, another substrate 20 with the clad 2A is prepared (FIG. 14C), and the core material 1 is sandwiched between the substrate 10 having the pattern-like recesses (FIG. 14D).
[0026]
The core material 1 is cured by a method such as ultraviolet irradiation from either or both of the other substrate side and the substrate having the pattern-like concave portion to form the core pattern 1A (FIG. 14 (e)), and the substrate 10 is peeled off to form the core pattern. 1A is transferred to the other substrate 20 side. Then, a metal is deposited on the inclined surface of the core pattern 1A to form the metal mirror 4 (FIG. 14F). Usually, it covers with the clad 3 (FIG.14 (g)). Also in this case, stable core formation is possible by surface treatment.
[0027]
Furthermore, it goes without saying that not only a concave shape (substrate having a pattern-like concave portion) but also a convex shape (substrate 11 having a pattern-like convex portion) can be used as the mold. For example, as shown in FIG. 15, a clad 2A having a patterned concave portion is produced using a surface-treated convex mold 11, and after forming a metal mirror 4, a core 1A is embedded and covered with the clad 3A to produce a waveguide. can do.
[0028]
【Example】
Below, the manufacturing method of the optical waveguide by this invention is demonstrated in detail in an Example.
<Example 1>
[Production of substrate having pattern-like recesses]
This will be described with reference to FIG. First, a thick photoresist is applied, baked, exposed, and developed on a substrate 31 (glass) to form a plurality of convex optical waveguide patterns having a height of 40 μm and a width of 20 μm to 150 μm as the resist pattern 32. (FIG. 6A).
[0029]
Next, by obliquely irradiating a KrF excimer laser as the laser beam 33, a portion to be an optical path conversion mirror is processed (FIG. 6B), and a substrate 30 having a pattern-like convex portion is obtained (FIG. 6C). ).
Next, the substrate 10 having a pattern-like recess was produced by taking a mold 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, the board | substrate 10 (silicone resin) which has a pattern-shaped recessed part was prepared (FIG. 1 (a)). Next, an oxygen plasma treatment was performed on the substrate having the pattern-like recesses (FIG. 1B). The apparatus used 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.
And the ultraviolet curable epoxy resin was apply | coated to the whole surface as the core material 1, and the core material 1 other than a recessed part was scraped off with the spatula 8. FIG. 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, the 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 the entire surface was spin-coated with an ultraviolet curable epoxy resin as the clad material 2 (FIG. 1 (e)).
In this state, 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 the clad 2A by irradiating ultraviolet rays from the side of another substrate (FIG. 1 (f)). .
[0033]
After peeling off the substrate 10 having the pattern-like recesses, metal Al was deposited on the inclined surface by mask deposition to form the metal mirror 4. Further, an ultraviolet curable epoxy resin was applied to the entire surface as the clad material 3 and irradiated with ultraviolet rays to complete the optical waveguide 5.
[0034]
<Example 2>
[Fabrication of optical waveguide 2]
The contact angle of the core material on the silicone was measured by changing the oxygen plasma treatment conditions such that the oxygen flow rate was 100 SCCM and the pressure was constant at 60 Pa, the plasma power was 20 W to 400 W, and the time was 1 second to 10 minutes.
As shown in FIG. 7, it was confirmed that the contact angle of the untreated silicone was about 60 °, whereas it changed to about 40 ° to 25 ° by the oxygen plasma treatment. Then, in any of the oxygen plasma treatments shown in FIG. 7, an optical waveguide could be produced in the same manner as in Example 1.
[0035]
<Example 3>
[Fabrication 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 oxygen plasma treatment was performed on the substrate having a patterned concave portion (FIG. 14B).
[0036]
On the other hand, another substrate 20 (glass) was prepared, and the entire surface was spin-coated with an ultraviolet curable epoxy resin as the clad material 2 and irradiated with ultraviolet rays to form a clad 2A (FIG. 14C).
[0037]
Then, the core material 1 was sandwiched between the substrate 10 having the pattern-like recess and the substrate 20 with the clad 2A, and the core pattern 1A was formed by irradiating ultraviolet rays from the substrate 20 side (FIG. 14D ) To (e)).
[0038]
After peeling off the substrate 10 having the pattern-shaped recess, metal Al was deposited on the inclined surface by mask deposition to form a metal mirror 4 (FIG. 14 (f)). Further, an ultraviolet curable epoxy resin was applied to the entire surface as the clad material 3 and cured with ultraviolet rays to complete the optical waveguide 5 (FIG. 14 (g)).
[0039]
<Example 4>
[Fabrication of optical waveguide 6]
This will be described with reference to FIG. First, a (silicone) substrate 11 having a pattern-like convex portion was prepared by a method similar to that in Example 1 (FIG. 15A), and oxygen plasma treatment was performed on the substrate 11 having the pattern-like convex portion (FIG. 15). 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 clad material 2 (FIG. 15C), and is superposed on the substrate having the pattern-shaped convex portion and irradiated with ultraviolet rays. Thus, the clad 2A was obtained (FIG. 15D).
[0041]
And the board | substrate 11 which has a pattern-shaped convex part was peeled off (FIG.15 (e)), and metal Al was vapor-deposited on the inclined surface by mask vapor deposition, and it was set as the metal mirror 4 (FIG.15 (f)). Further, an ultraviolet curable epoxy resin was applied to the entire surface as the core material 1, and the core material 1 other than the recesses was scraped off with a spatula 8. By irradiating the entire surface with ultraviolet rays, the core material 1 was cured to form a core pattern 1A (FIGS. 15G to 15H).
[0042]
Finally, an ultraviolet curable epoxy resin was applied to the entire surface as the clad material 3 and cured with ultraviolet rays to complete the optical waveguide 5 (FIG. 15 (i)).
[0043]
<Comparative Example 1>
[Fabrication of optical waveguide 3]
This will be described with reference to FIGS. First, a substrate 10 (silicone resin) having a patterned recess was prepared in accordance with [Production of substrate having a patterned recess] in Example 1 (FIG. 8A). Next, without performing a special surface treatment, an ultraviolet curable epoxy resin was applied to the entire surface as the core material 1, and the core material 1 other than the recesses was scraped off with a spatula 8. By irradiating the entire surface with ultraviolet rays, the core 1 was cured to form 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 core 1A was likely to be disconnected (FIG. 9), and it was difficult to form a continuous waveguide. .
[0045]
<Comparative example 2>
[Fabrication of optical waveguide 5]
A waveguide was fabricated 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-like recess and the substrate 20 with the clad 2A (FIG. 14D), and then the substrate 20 side is irradiated with ultraviolet rays (FIG. 14E )), The substrate 10 having the pattern-like recesses was easily peeled off, and a clean core pattern 1A could not be formed.
[0046]
<Comparative Example 3>
[Fabrication of optical waveguide 7]
A waveguide was fabricated in the same manner as in Example 4 except that no special surface treatment was performed. In that case, when the substrate 20 with the clad material 2 was superposed on the substrate 11 having the pattern-like convex portions, the clad material 2 did not spread well, and a clean clad 2A could not be formed.
[0047]
【The invention's effect】
In the present invention, the surface treatment for increasing the affinity of the core material is performed on the surface of the substrate having the pattern-like recess before filling only the pattern-like recess of the substrate having the pattern-like recess, so that the stable core pattern 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 it again, and metal deposition on the inclined surface can be performed in a process that is continuous with the manufacturing process of the core pattern.
That is, it becomes an optical waveguide manufacturing method capable of manufacturing a stable polymer optical waveguide at low cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an embodiment of a method for producing an optical waveguide according to the present invention.
FIG. 2 is a cross-sectional view illustrating an example of a method for producing a multilayer optical waveguide according to the present invention.
3 is a cross-sectional view of a core pattern in Example 1. FIG.
FIG. 4 is a perspective view showing an example of an optical waveguide according to 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 showing an example of a method for producing a substrate having a patterned recess according to the present invention.
FIG. 7 is an explanatory view showing a change in contact angle due to oxygen plasma treatment.
8 is a cross-sectional view showing a method for manufacturing an optical waveguide in Comparative Example 1. FIG.
9 is a cross-sectional view of a core pattern in Comparative Example 1. FIG.
FIG. 10 is a cross-sectional view showing 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 showing an example of a conventional method for manufacturing an optical path conversion mirror.
FIG. 13 is a cross-sectional view showing an example of a manufacturing method for continuously manufacturing a conventional optical waveguide and an optical path conversion mirror.
14 is a cross-sectional view showing the method of manufacturing the optical waveguide in Example 3. FIG.
15 is a cross-sectional view showing the method of manufacturing the optical waveguide in Example 4. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1 '... Core material 1A, 1'A ... Core pattern 2, 3 ... Cladding material 2A, 3A, 3'A ... Cladding 4, 4', 4 "... Metal mirror 5 ... Optical waveguide 6 ... Multilayer optical waveguide 7 ... Optical path 8 ... Spatula 10, 10 '... Substrate 11 having pattern-like recesses ... Substrate 20 having pattern-like projections ... Separate substrate 30 ... Substrate 31, 50 having pattern-like projections ... Substrate 32 ... Photoresist or epoxy resin 33 ... Laser beam 34 ... Silicone resin 51 ... Silicon-containing resist or metal mask 52 ... Reactive ions 53 ... Ultraviolet exposure 54 ... Dicing blade 55 ... Total reflection mirror 56 ... Adhesive

Claims (7)

A method of manufacturing an optical waveguide, wherein a core pattern is formed using a mold having at least a surface made of silicone resin,
The mold is a substrate having a pattern-like recess;
1) A step of filling a core only in a pattern-like recess of a substrate having a pattern-like recess and superimposing it on a clad surface of another substrate on which a clad has been previously applied;
2) peeling the substrate having the pattern-like recesses, and transferring the core pattern onto the clad;
3) providing a clad material covering the clad and the core pattern;
A method of manufacturing an optical waveguide comprising at least an oxygen plasma that increases the affinity of a core material on the surface of a substrate having a patterned recess before filling the core only in the patterned recess of the substrate having a patterned recess A method for manufacturing an optical waveguide, comprising performing processing. A method of manufacturing an optical waveguide, wherein a core pattern is formed using a mold having at least a surface made of silicone resin,
The mold is a substrate having a pattern-like convex portion,
1) a step of pre-clad to form a cladding having a copy and up pattern recess the shape of a substrate having a patterned projections on the cladding surface of another substrate coated,
2) a step of embedding a core in a concave portion of a clad having a patterned concave portion
3) providing a clad material covering the clad and the core pattern;
The method of manufacturing an optical waveguide comprising at least an oxygen plasma treatment for increasing the affinity of a clad material on the surface of a substrate having a pattern-like convex portion before copying the shape of the substrate having the pattern-like convex portion to the clad. A method for manufacturing an optical waveguide, comprising:   3. The method for manufacturing an optical waveguide 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 in the pattern-like recesses of the substrate having the pattern-like recesses is a method of scraping off the excess core material with a spatula after applying the core material to the substrate having the pattern-like recesses. The method for manufacturing an optical waveguide according to claim 1.   The step of filling only the pattern-like recesses of the substrate having the pattern-like recesses with the core material and overlaying it with the clad surface of another substrate on which the clad has been applied in advance is performed separately from the substrate having the pattern-like recesses. 2. The method of manufacturing an optical waveguide according to claim 1, wherein the core material is sandwiched between the substrate and the substrate. The optical waveguide provided with a clad material covering the clad and the core pattern in the step 3 is used as another substrate on which the clad has been applied in the step 1 in advance. A method of manufacturing an optical waveguide according to claim 4 or 5 .   The oxygen plasma treatment is a surface treatment in which a contact angle of the core material with respect to the mold is set to 45 ° or less, and the oxygen plasma treatment is characterized in that the oxygen plasma treatment is performed. Item 7. A method for manufacturing an optical waveguide according to Item 6.

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