JP2002022993A - Method for manufacturing optical waveguide device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing optical waveguide device in which a resin optical waveguide is mounted on an inorganic material substrate and is suitable for mass production. SOLUTION: This process has a first process step of forming a lower clad layer by a resin over the entire part of the top surface of the inorganic material substrate 1, a second process step of forming a plurality of the optical waveguides 4 of a predetermined shape made of the resin on the lower clad layer by longitudinally and transversely arraying the optical waveguide, a third process step of forming an upper clad layer covering the entire part of the top of the substrate 1 by the resin and a fourth process step of disconnecting the individual optical waveguides 4 by cutting the substrate 1 for every longitudinally and transversely arrayed optical waveguide. A removing process step of removing the lower clad layer and the upper clad layer to the form of belts 50 and 51 from the top of the substrate 1 along a position cut in the fourth step during the third step and the fourth step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an optical waveguide,
In particular, the present invention relates to a resin optical waveguide mounted on an inorganic material substrate.

[0002]

2. Description of the Related Art With the spread of personal computers and the Internet in recent years, the demand for information transmission has rapidly increased. For this reason, it is desired that optical transmission with a high transmission speed be spread to terminal information processing devices such as personal computers. To achieve this, it is necessary to manufacture high-performance optical waveguides for optical interconnection at low cost and in large quantities.

As materials for optical waveguides, inorganic materials such as glass and semiconductor materials and resins are known. When an optical waveguide is manufactured from an inorganic material, a method is used in which an inorganic material film is formed by a film forming apparatus such as a vacuum evaporation apparatus or a sputtering apparatus, and the inorganic film is etched into a desired waveguide shape. . However, the vacuum evaporation apparatus and the sputtering apparatus require large-scale evacuation equipment, and are therefore large and expensive. In addition, since the evacuation step is required, the step becomes complicated. On the other hand, when an optical waveguide is manufactured using a resin, the film forming process can be performed at atmospheric pressure by coating and heating, and thus there is an advantage that the apparatus and the process are simple.

Various resins are known as resins constituting the optical waveguide and the cladding layer. Polyimides having a high glass transition temperature (Tg) and excellent heat resistance are particularly expected. When the optical waveguide and cladding layer are formed of polyimide, long-term reliability can be expected,
It can withstand soldering.

[0005]

The optical waveguide made of resin is:
Generally, it is constituted by laminating a resin lower clad layer, an optical waveguide layer and an upper clad layer on a substrate. In order to mass-produce such an optical waveguide, a large substrate such as a wafer is used as a substrate, and a large number of optical waveguides are arranged on the substrate, formed and patterned at a time, and then the substrate is cut by dicing or the like. In this way, it is possible to use a method for forming individual optical waveguide devices. As the substrate, an inorganic material substrate such as a Si substrate, a quartz substrate, or a glass substrate is often used because a substrate having a smooth surface with high accuracy is easily available. When a structure in which the inorganic material and the resin are laminated is cut into individual optical waveguide devices by dicing during mass production, the dicing blade must cut both the inorganic material and the resin layer. However, when a coarse dicing blade suitable for cutting an inorganic material is used as a dicing blade, there is a problem that the resin is clogged between the abrasive grains of the dicing blade and the cut surface becomes rough. Further, stress is concentrated on the cut surface of the cladding layer of the resin layer or the optical waveguide layer at the time of dicing, and a force is applied to the resin at the time of cutting, so that there is a problem that these layers are easily peeled off from the end face. On the other hand, if a dicing blade suitable for cutting the resin layer is used, a problem arises in that the inorganic material substrate cannot be cut.

[0006] Further, when the end face of the resin optical waveguide is finished by polishing, there are problems such as that an abrasive or a foreign substance adheres to the upper surface of the resin layer, and that the upper surface of the resin layer is damaged during cleaning. .

According to the present invention, there is provided a method for manufacturing an optical waveguide device in which a resin optical waveguide is mounted on an inorganic material substrate,
An object is to provide a method for manufacturing an optical waveguide device suitable for mass production.

[0008]

According to the present invention, there is provided a method of manufacturing an optical waveguide device as described below.

That is, a first step of forming a lower cladding layer of a resin on the entire upper surface of an inorganic material substrate, and a plurality of resin-made optical waveguides (cores) of a predetermined shape on the lower cladding layer. A second step of forming the upper clad layer covering the entire upper surface of the substrate with a resin, and a step of cutting the substrate for each of the optical waveguides arranged in the vertical and horizontal directions. A fourth step of separating the individual optical waveguides, and between the third step and the fourth step, along the position cut in the fourth step, the lower part A method for manufacturing an optical waveguide device, comprising performing a stripping step of stripping a clad layer and an upper clad layer from the substrate.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.

First, the configuration of an optical waveguide device 100 manufactured by the manufacturing method according to the first embodiment of the present invention will be described with reference to FIGS. Optical waveguide device 100
Has a configuration in which an optical waveguide laminate 10 is provided on a Si substrate 1 and an electrode portion 7 is arranged in a region where the optical waveguide laminate 10 is not arranged.

The optical waveguide laminate 10 comprises a lower cladding layer 3 disposed on a silicon substrate 1, an optical waveguide 4 mounted thereon, an upper cladding layer 5 for embedding the optical waveguide 4, and a protective layer 9 And

Lower cladding layer 3 and upper cladding layer 5
Are all OPI-N10 manufactured by Hitachi Chemical Co., Ltd.
05 (trade name). The thickness of the lower cladding layer 3 is about 6 μm, and the thickness of the upper cladding layer 5 is about 12 μm from the surface of the lower cladding layer. The optical waveguide 4 is an OPI- manufactured by Hitachi Chemical Co., Ltd.
A polyimide film formed by using N3205 (trade name), the film thickness is about 6 μm, and the width of the optical waveguide 4 is about 6 μm.
μm. The protective layer 9 is a polyimide film formed using PIX-6400 (trade name) manufactured by Hitachi Chemical DuPont Microsystems Co., Ltd. The film thickness is about 5 μm at an end portion away from the optical waveguide 4. .

The electrode section 7 is arranged on the silicon substrate 1. The electrodes are electrodes for mounting a light emitting element, a light receiving element for monitoring the output of the light emitting element, a light receiving element, and the like.

Next, a method of manufacturing the optical waveguide device according to the present embodiment will be described with reference to FIGS.
(D), (e), FIG. 5, FIG. 6 (a) to (d), and FIG.

Here, the substrate 1 has a diameter of about 12.7c.
3 are formed on the substrate 1 by arranging a large number of the structures shown in FIG. 3 and then separated by dicing in a later step to manufacture a large number of the optical waveguide devices 100 shown in FIG. 1 (a) to 1 (c) and FIG.
(D) and (e) show only a part of the wafer-like substrate 1 which is to be one optical waveguide device 100, for convenience of illustration. Further, film formation, patterning, and the like are performed at once on the entire wafer-shaped substrate 1.

First, a metal film is formed on the entire upper surface of a wafer-like substrate 1 and patterned to obtain a structure shown in FIG.
The electrode 7 is formed as shown in FIG.

Next, the above-described OPI
-N1005 is spin-coated to form a material solution film.
Then, at 100 ° C for 30 minutes in a drier, then 200 ° C
The solvent is evaporated by heating for 30 minutes at
Cured by heating at 70 ° C for 60 minutes, thickness 6μ
Then, the lower clad layer 3 having a thickness of m is formed (FIG. 1B).

On the lower cladding layer 3, the above-mentioned OP
A material solution film is formed by spin coating I-N3205. Then, it was dried at 100 ° C. for 30 minutes,
The solvent is evaporated by heating at 0 ° C. for 30 minutes, and then cured by heating at 350 ° C. for 60 minutes to form a 6 μm thick polyimide film to be the optical waveguide 4.
Next, this polyimide film is patterned into the shape of the optical waveguide 4 by photolithography. Specifically, a resist is spin-coated on the polyimide layer to be the optical waveguide 4, dried, and then exposed to a mask image using a mercury lamp. Next, the resist is developed to form a resist pattern layer. This resist pattern layer is used as a mask for processing the above-described polyimide film into the shape of the optical waveguide 4. By using the resist pattern layer as a mask, the above-mentioned polyimide layer is subjected to reactive ion etching (O ₂ -R1E) with oxygen, whereby the optical waveguide 4 is formed on the substrate 1.
It can be formed by arranging a large number on the
(C)). After that, the resist pattern layer is peeled off.

Next, OPI-N1005 is spin-coated so as to cover the optical waveguide 4 and the lower cladding layer 3. The obtained material solution film is dried in an oven at 100 ° C. for 30 minutes.
And then heated at 200 ° C. for 30 minutes to evaporate the solvent in the material solution film, and heated at 350 ° C. for 60 minutes to form an upper clad layer 5 of a polyimide film.
(D)).

Further, on the upper surface of the upper cladding layer 5, a PI
X-6400 is spin-coated and dried in a dryer at 100 ° C. for 30 minutes.
After heating at 200 ° C. for 30 minutes to evaporate the solvent, and subsequently heating at 350 ° C. for 60 minutes, a protective layer 9 of a 5 μm thick polyimide film having a substantially flat upper surface is obtained.

Next, along the direction in which the optical waveguides 4 are arranged on the wafer-like substrate 1, two wires are formed by dicing on both sides of the electrode portion 7, that is, at the boundary between the electrode portion 7 and the optical waveguide laminate 10. Are cut in parallel, and the optical waveguide laminate 10 above the electrode portion 7 is stripped off from the substrate 1 as shown in FIG. At this time, the depth of cut by dicing is
The optical waveguide laminate 10 is separated, but the substrate 1 is set to a depth that does not separate. Therefore, at this time, the substrate 1 is
And remains in the shape of a wafer. Since the dicing at this time cuts the optical waveguide laminate 10 of the resin layer, a blade having a roughness suitable for cutting the resin is used as the dicing blade. Therefore, inconvenience such as clogging of the dicing blade does not occur. In this manner, the striped optical waveguide laminate 10 is removed, and the electrode exposure line 50 is removed.
In the region of the electrode portion 7 on the substrate 1, the electrode portion 7 and the silicon substrate 1 are exposed. Further, the optical waveguide laminate 10 has a shape shown in FIG. 2E in which the end face of the optical waveguide 4 is exposed toward the electrode portion 7.

Next, a Au / Sn solder layer having a desired shape is formed on the exposed electrode portion 7. Next, along the direction in which the optical waveguides 4 are arranged on the wafer-like substrate 1,
The scribe line 51 is formed by removing the lower clad layer 3, the upper clad layer 5, and the protective layer 9 at the boundary between the adjacent optical waveguides 4 into strips having a predetermined width. The scribe line 51 is orthogonal to the electrode exposure line 50 formed in the previous step, as shown in FIG. The formation of the scribe line 51 is based on the scribe line 5
Masking is performed on portions other than 1 with a resist or a metal film, and the lower clad layer 3, the upper clad layer 5, and the protective layer 9 are removed by dry etching using oxygen gas or plasma ashing using oxygen gas. The position where the scribe line 51 is provided is determined by the step of dividing the optical waveguide device 100 described later (FIG. 6).
(C) is a position to be cut by dicing. The width of the scribe line 51 is set to be wider than the width of the dicing blade used in the dicing step in FIG. Here, since the dicing blade having a width of 100 μm is used in FIG. 6C, the width of the scribe line 51 is set to 300 μm.

Next, the wafer-like substrate 1 is cut by dicing as shown in FIG. 6A, and the substrate 1 is cut into strips. At this time, the position cut by dicing is the position of the electrode exposure line 50.

Next, as shown in FIG. 6B, a coating material is applied to the upper surface of the strip-shaped substrate 1, and the optical waveguide laminate 10 and the electrode portion 7 are covered with a film of the coating material. In the subsequent polishing process of the side surface 11, the coating material film may cause abrasives or foreign substances to adhere to the optical waveguide laminate 10 or the electrode portion 7,
It acts to prevent scratches during cleaning. Here, Skycoat NAR-3011 (trade name) manufactured by Nikka Seiko Co., Ltd. is used as the coating material. As shown in FIG. 7, a method of spraying a coating material on the optical waveguide laminate 10 and the electrode portion 7 or a method of spreading the entire surface of the optical waveguide laminate 10 and the electrode portion 7 by spin coating can be used.

Next, the side surface 11 of the strip-shaped substrate 1 shown in FIG. 6B is polished, and the end surface of the optical waveguide 4 is polished. At this time, since the upper surfaces of the optical waveguide laminate 10 and the electrode portion 7 are protected by the coating material, there is no possibility that an abrasive or a foreign substance adheres or is damaged.

Next, the strip-shaped substrate 1 is cut out along the scribe lines 51 by dicing to complete the optical waveguide device 100 (FIGS. 6C and 6D). At this time, since the scribe line 51 has the resin layers of the upper and lower cladding layers 3 and 5 and the protective layer 9 removed as shown in FIG. 8A, it is the Si substrate 1 that the dicing blade cuts. . Therefore, a dicing blade suitable for cutting the Si substrate 1 can be used. Since the width of the scribe line 51 is wider than the width of the dicing blade, the dicing blade is
Since the resin layer such as the upper and lower clad layers 3 and 5 is not touched as shown in FIG. 3B, the dicing blade is not clogged with the resin. Further, since no stress is applied to the end surfaces of the upper and lower clad layers 3, 5 and the like at the time of dicing, there is no possibility that the upper and lower clad layers 3, 5 are peeled from the cut portion. Therefore, the substrate 1 can be efficiently and precisely cut to singulate the optical waveguide device 100. The coating material is
After singulation, peel off by alcohol washing or the like.

As a comparative example, the substrate 1 was formed in the same manner as in this embodiment except that the scribe line 51 was not formed.
Was diced into individual pieces. A dicing blade suitable for cutting the Si substrate 1 was used. In this case, the dicing blade cuts the resin layers such as the lower and upper cladding layers 3 and 5 and the substrate 1 at the same time as shown in FIG. 8C, so that the dicing blade is clogged with the resin, The cutting surface became rough. Further, since a force is applied to the resin at the time of cutting, a phenomenon occurs in which the end portions of the lower and upper clad layers 3, 5 and the like are easily peeled off.

As described above, in the optical waveguide device 100 manufactured in the present embodiment, the optical waveguide laminate 10 of the resin layer is mounted on the inorganic material substrate 1 and a line is formed in which the resin is removed in a strip shape in advance. Because of the structure of the inorganic material / resin described above, even in the structure of the inorganic material / resin / inorganic material, the resin layers such as the lower and upper clad layers 3 and 5 are previously removed in a strip shape from the portions cut out by dicing. This makes it possible to cut out by dicing smoothly and efficiently. Therefore, by using the manufacturing method of the present embodiment, a high-precision optical waveguide device made of resin can be efficiently mass-produced.

Although the present embodiment includes a step of polishing the end face of the optical waveguide 4, the upper surface of the optical waveguide laminate 10 and the upper surface of the electrode portion 7 are coated with a coating material during polishing. This prevents foreign matter from adhering to the optical waveguide laminate 10 and the electrode portion 7 and causing no damage. If a foreign substance adheres or scratches on these, it may affect the propagation characteristics of the optical waveguide, or the corrosion resistance may be degraded from the scratches or the foreign matter, but in the present embodiment,
Since the upper surface is clean and free from scratches, an optical waveguide device having stable performance can be mass-produced.

In the first embodiment, the electrode exposing lines 50 are formed by dicing, and the scribe lines 51 are formed by dry etching or ashing.
It can also be formed at once by dry etching using oxygen gas. Other steps are the same as those in the first embodiment. As described above, by forming the electrode exposure line 50 and the scribe line 51 at the same time at the same time, an effect that the manufacturing process can be simplified as compared with the first embodiment can be obtained.

Further, the scribe line 51 can be formed by dicing. In this case, when the width of the scribe line 51 is wide, it can be formed by making cuts on both sides of the scribe line 51 like the electrode exposure line 50 and peeling off the lower and upper clad layers 3 and 5. Alternatively, the scribe line 51 can be formed by cutting the lower and upper clad layers 3 and 5 with a dicing blade having the same thickness as the width of the scribe line 51.

In the optical waveguide device 100 manufactured in the above-described embodiment, since all layers from the lower cladding layer 3 to the protective layer 9 are formed of polyimide, Tg
With high heat resistance. Therefore, the optical waveguide device of the present embodiment can maintain the propagation characteristics even at a high temperature. Further, since polyimide can withstand a high-temperature process such as soldering, it is possible to solder another optical waveguide device, an electric circuit element, or a light emitting / receiving element on the optical waveguide device.

Optical waveguide device 100 of the present embodiment
Is efficient in dicing by using a manufacturing method in which a resin layer in a dicing portion is removed in advance while having a laminated structure of inorganic material / resin in which a resin optical waveguide laminate 10 is mounted on an inorganic material substrate 1. In addition, no force is applied to the resin layer during dicing. Therefore, it is possible to mass-produce the optical waveguide device having excellent optical characteristics according to the present embodiment at low cost.

[0035]

As described above, according to the present invention,
A method for manufacturing an optical waveguide device in which a resin optical waveguide is mounted on an inorganic material substrate, and a method for manufacturing an optical waveguide device suitable for mass production can be provided.

[Brief description of the drawings]

FIGS. 1A to 1C are cutaway perspective views showing a schematic method for manufacturing an optical waveguide device according to an embodiment of the present invention.

FIGS. 2D and 2E are cutaway perspective views illustrating a method for manufacturing a schematic optical waveguide device according to an embodiment of the present invention.

FIG. 3 is a perspective view illustrating a configuration of a schematic optical waveguide device manufactured by a manufacturing method according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of the optical waveguide device taken along line AA ′ of FIG. 3;

FIG. 5 is a top view showing a step of forming an electrode exposure line 50 and a scribe line 51 in the method for manufacturing an optical waveguide device according to one embodiment of the present invention.

FIG. 6A is a top view and a partial cross-sectional view of the substrate 1 showing a dicing position at which the wafer-like substrate 1 is cut into strips in the method for manufacturing an optical waveguide device according to one embodiment of the present invention. (B) is a top view and a cross-sectional view showing the state of the strip-shaped substrate 1, and (c) is a view showing the state of the strip-shaped substrate 1.
It is a top view showing a dicing position where the
(D) is a top view showing the individualized optical waveguide device.

FIG. 7 is an explanatory view showing a step of applying a coating material on the substrate 1 cut into strips in the method for manufacturing an optical waveguide device according to one embodiment of the present invention.

FIG. 8A is a diagram illustrating a dicing process in a method of manufacturing an optical waveguide device according to an embodiment of the present invention;
FIG. 4B is a cross-sectional view, FIG. 4B is an explanatory diagram showing a positional relationship between the dicing blade and the scribe line 51 viewed from the top, and FIG. 4C is a scribe line 51 of a comparative example.
FIG. 4 is an explanatory diagram showing a relationship between a dicing blade and a resin layer when no dicing blade is provided.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Silicon substrate 3 ... Lower clad layer 4 ... Optical waveguide 5 ... Upper clad layer 7 ... Electrode part 9 ... Protective layer 10 ... Optical waveguide laminated body 50 ... Electrode exposure line 51: scribe line 100: optical waveguide device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tohru Takahashi 48 Wadai, Tsukuba, Ibaraki Prefecture Within Hitachi Chemical Co., Ltd. (72) Inventor Masatoshi Yamaguchi 48 Wadai, Tsukuba, Ibaraki Prefecture Hitachi Chemical Co., Ltd. In-house (72) Inventor Toshihiro Kuroda 48 Wadai, Tsukuba-shi, Ibaraki F-term in Hitachi Chemical Co., Ltd. Research Laboratory 2H047 KA04 MA07 PA24 PA26 PA28 QA02 QA04 QA07 TA41

Claims (9)

[Claims] 1. A first step of forming a lower cladding layer of a resin on the entire upper surface of an inorganic material substrate, and a plurality of optical waveguides of a predetermined shape made of resin are vertically and horizontally formed on the lower cladding layer. A second step of forming an array, a third step of forming an upper clad layer covering the entire upper surface of the substrate with a resin, and cutting the substrate for each of the optical waveguides arranged vertically and horizontally, A fourth step of separating the individual optical waveguides, wherein between the third step and the fourth step, the lower clad layer and A method for manufacturing an optical waveguide device, comprising: performing a stripping step of stripping an upper clad layer from above the substrate. 2. The method of manufacturing an optical waveguide device according to claim 1, wherein in the fourth step, the cutting is performed by dicing using a dicing blade, and the width of the strip portion to be removed in the removing step is A method for manufacturing an optical waveguide device, wherein the thickness is larger than the thickness of a dicing blade. 3. The method of manufacturing an optical waveguide device according to claim 2, wherein the fourth step is performed so that the dicing blade does not contact the lower and upper clad layers. Manufacturing method of waveguide device. 4. The method of manufacturing an optical waveguide device according to claim 2, wherein the removing step cuts the lower and upper clad layers of the strip to be removed by dicing using a dicing blade. A method of manufacturing an optical waveguide device, comprising: removing the lower and upper clad layers from the substrate after the insertion. 5. The method for manufacturing an optical waveguide device according to claim 4, wherein a resin cutting blade is used as the dicing blade used in the removing step.
Using a blade for cutting an inorganic material as the dicing blade used in the step (c). 6. The method of manufacturing an optical waveguide device according to claim 1, wherein the removing step is performed by dry etching or ashing. 7. A first step of forming a lower clad layer of a resin on the entire upper surface of an inorganic material substrate, and forming a plurality of resin optical waveguides of a predetermined shape on the lower clad layer vertically and horizontally. A second step of forming and arranging; a third step of forming an upper clad layer covering the entire upper surface of the substrate with a resin; a fourth step of cutting the substrate; and a cutting in the fourth step A fifth step of polishing at least a part of the cut surface of the cut substrate, wherein between the fourth step and the fifth step, an upper surface of the upper clad layer of the cut substrate is provided. And a coating process for applying a coating material to protect the upper surface during the polishing. 8. The method of manufacturing an optical waveguide device according to claim 7, further comprising, after the fifth step, a step of separating the individual optical waveguides by further cutting the substrate. A method for manufacturing an optical waveguide device. 9. The method of manufacturing an optical waveguide device according to claim 1, wherein the inorganic material other than resin to be cut is silicon or glass. Method.