JP4379902B2 - Manufacturing method of optical waveguide device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical waveguide, and more particularly to a resinous optical waveguide mounted on an inorganic material substrate.
[0002]
[Prior art]
With the recent spread of personal computers and the Internet, information transmission demand is rapidly increasing. For this reason, it is desired to spread optical transmission having a high transmission speed to an end information processing apparatus such as a personal computer. In order to realize this, it is necessary to manufacture a high-performance optical waveguide for optical interconnection at low cost and in large quantities.
[0003]
As materials for optical waveguides, inorganic materials such as glass and semiconductor materials, and resins are known. In the case of manufacturing an optical waveguide 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 deposition apparatus or a sputtering apparatus, and this is etched into a desired waveguide shape. . However, the vacuum vapor deposition apparatus and the sputtering apparatus require a vacuum exhaust equipment, so that the apparatus is large and expensive. Moreover, since a vacuum exhaust process is required, the process becomes complicated. On the other hand, when an optical waveguide is manufactured from a resin, the film forming process can be performed at atmospheric pressure by application and heating, and thus there is an advantage that the apparatus and the process are simple.
[0004]
Various resins are known as the optical waveguide and the clad layer, and a polyimide having a high glass transition temperature (Tg) and excellent heat resistance is particularly expected. When the optical waveguide and the clad layer are formed of polyimide, long-term reliability can be expected, and it can withstand soldering.
[0005]
[Problems to be solved by the invention]
A resin-made optical waveguide is generally configured by laminating a resin-made 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, a large number of optical waveguides are arranged on the substrate, and after film formation and patterning at once, the substrate is cut by dicing or the like. Thus, it is possible to use a method of making individual optical waveguide devices. 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 easy to obtain. When a structure in which these inorganic materials and a resin are laminated is cut into individual optical waveguide devices by dicing at the time of 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 the dicing blade, there is a problem that the resin is clogged between the abrasive grains of the dicing blade and the cutting surface becomes rough. Further, there is a problem that stress is concentrated on the cutting surface of the clad layer of the resin layer and the optical waveguide layer at the time of dicing, and further, a force is applied to the resin at the time of cutting, so that these layers are easily peeled off from the end surface. On the other hand, when a dicing blade suitable for cutting the resin layer is used, there arises a problem 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 abrasives and foreign matters adhering to the upper surface of the resin layer, and scratches on the upper surface of the resin layer during cleaning.
[0007]
An object of the present invention is to provide an optical waveguide device manufacturing method in which a resin optical waveguide is mounted on an inorganic material substrate, which is suitable for mass production.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, the following optical waveguide device manufacturing method is provided.
[0009]
That is, a first step of forming a lower clad layer with a resin on the entire top surface of the inorganic material substrate;
A second step of forming a plurality of resin-made optical waveguides (cores) arranged vertically and horizontally on the lower cladding layer;
A third step of forming an upper clad layer covering the entire upper surface of the substrate with a resin, and a fourth step of cutting the substrate for each of the optical waveguides arranged in the vertical and horizontal directions to separate the individual optical waveguides And
A removal step of removing the lower clad layer and the upper clad layer from the substrate in a band shape is performed between the third step and the fourth step along the position cut in the fourth step. This is a method for manufacturing an optical waveguide device.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described.
[0011]
First, the configuration of the 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. The optical waveguide device 100 has a configuration in which an optical waveguide stack 10 is provided on a Si substrate 1 and an electrode portion 7 is disposed in a region where the optical waveguide stack 10 is not disposed.
[0012]
The optical waveguide laminate 10 includes a lower cladding layer 3 disposed on the silicon substrate 1, an optical waveguide 4 mounted thereon, an upper cladding layer 5 that embeds the optical waveguide 4, and a protective layer 9. It is out.
[0013]
The lower clad layer 3 and the upper clad layer 5 are both made of a polyimide film formed using Hitachi Chemical Co., Ltd. OPI-N1005 (trade name). The film thickness of the lower clad layer 3 is about 6 μm, and the film thickness of the upper clad layer 5 is about 12 μm from the surface of the lower clad layer. The optical waveguide 4 is made of a polyimide film formed using OPI-N3205 (trade name) manufactured by Hitachi Chemical Co., Ltd. The film thickness is about 6 μm, and the width of the optical waveguide 4 is about 6 μm. The protective layer 9 is a polyimide film formed using PIX-6400 (trade name) manufactured by Hitachi Chemical DuPont Microsystems Co., Ltd., and the film thickness is about 5 μm at the end portion away from the optical waveguide 4. .
[0014]
The electrode unit 7 is disposed 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.
[0015]
Next, with respect to the method of manufacturing the optical waveguide device of the present embodiment, FIGS. 1 (a) to (c), FIGS. 2 (d) and (e), FIG. 5, FIGS. 6 (a) to (d), FIG. 7 for explanation.
[0016]
Here, a silicon wafer having a diameter of about 12.7 cm is prepared as the substrate 1, and a large number of the structures shown in FIG. 3 are formed on the substrate 1 and separated by dicing in a later step. The optical waveguide device 100 is manufactured at a time. 1 (a) to 1 (c) and FIGS. 2 (d) and 2 (e), for convenience of illustration, only a part of the wafer-like substrate 1 that becomes one optical waveguide device 100 is cut out. This is shown in the figure. Further, film formation, patterning, and the like are performed on the entire wafer-like substrate 1 at once.
[0017]
First, an electrode 7 is formed as shown in FIG. 1A by forming a metal film on the entire upper surface of the wafer-like substrate 1 and patterning it.
[0018]
Next, the above-mentioned OPI-N1005 is spin-coated on the entire upper surface of the substrate 1 to form a material solution film. Thereafter, the solvent is evaporated by heating at 100 ° C. for 30 minutes in a dryer and then at 200 ° C. for 30 minutes, and subsequently cured by heating at 370 ° C. for 60 minutes, whereby the lower cladding layer 3 having a thickness of 6 μm is formed. Form (FIG. 1B).
[0019]
On the lower clad layer 3, the aforementioned OPI-N3205 is spin-coated to form a material solution film. Thereafter, the solvent is evaporated by heating at 100 ° C. for 30 minutes in a dryer and then at 200 ° C. for 30 minutes, followed by curing by heating at 350 ° C. for 60 minutes, resulting in an optical waveguide 4 having a thickness of 6 μm. The polyimide film is formed. Next, this polyimide film is patterned into the shape of the optical waveguide 4 by photolithography. Specifically, a resist is spin-coated on a polyimide layer to be the optical waveguide 4, and after drying, a mask image is exposed with 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 aforementioned polyimide film into the shape of the optical waveguide 4. By using this resist pattern layer as a mask, the above polyimide layer is subjected to reactive ion etching (O ₂ -R1E) with oxygen, whereby a large number of optical waveguides 4 can be arranged on the substrate 1 (see FIG. 1). c)). Thereafter, the resist pattern layer is peeled off.
[0020]
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 was heated in a dryer at 100 ° C. for 30 minutes, and then at 200 ° C. for 30 minutes to evaporate the solvent in the material solution film, and heated at 350 ° C. for 60 minutes, thereby heating the upper part of the polyimide film. The clad layer 5 is formed (FIG. 2D).
[0021]
Further, PIX-6400 is spin-coated on the upper surface of the upper clad layer 5, the solvent is evaporated by heating at 100 ° C. for 30 minutes and 200 ° C. for 30 minutes in a dryer, and subsequently heated at 350 ° C. for 60 minutes. Thus, a protective layer 9 made of a polyimide film having a thickness of 5 μm and a substantially flat upper surface is obtained.
[0022]
Next, along the direction in which the optical waveguides 4 are arranged on the wafer-like substrate 1, two parallel parts are formed by dicing at both sides of the electrode part 7, that is, at the boundary between the electrode part 7 and the optical waveguide laminate 10. An incision is made, and the optical waveguide laminate 10 on the upper part of the electrode part 7 is peeled off from the substrate 1 in a band shape as shown in FIG. At this time, the depth of the cut by dicing is set so that the optical waveguide laminate 10 is cut off but the substrate 1 is not cut off. Therefore, at this time, the substrate 1 remains in a wafer shape as shown in FIG. Moreover, since 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. Thus, the electrode waveguide 7 and the silicon substrate 1 are exposed in the region of the electrode section 7 on the substrate 1 by removing the optical waveguide laminate 10 in a band shape and forming the electrode exposure line 50. 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.
[0023]
Next, an 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 lower cladding layer 3, the upper cladding layer 5, and the protective layer 9 at the boundary between the adjacent optical waveguides 4 and 4 are placed in advance. A scribe line 51 is formed by removing the strip in 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 scribe line 51 is formed by masking portions other than the scribe line 51 with a resist or a metal film, and performing dry etching using oxygen gas or plasma ashing using oxygen gas, and the protective cladding layer 3, the upper cladding layer 5, and the protective layer. This is done by removing layer 9. The position where the scribe line 51 is provided is a position that is cut by dicing in the step of dividing the optical waveguide device 100 described later (FIG. 6C). The width of the scribe line 51 is set to be wider than the width of the dicing blade used in the dicing process in FIG. Here, since a 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.
[0024]
Next, the wafer-like substrate 1 is cut by dicing as shown in FIG. 6A, and the substrate 1 is cut into a strip shape. The position cut by dicing at this time is the position of the electrode exposure line 50.
[0025]
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 coating material film. This film of the coating material acts to prevent the abrasive and foreign matter from adhering to the optical waveguide laminate 10 and the electrode portion 7 and scratching during cleaning in the subsequent polishing process of the side surface 11. To do. Here, Skycoat NAR-3011 (trade name) manufactured by Nikka Seiko Co., Ltd. is used as the coating material. As shown in FIG. 7, it is possible to use a method of spraying a coating material on the top of the optical waveguide laminate 10 and the electrode part 7 or a method of spreading the entire upper surface of the optical waveguide laminate 10 and the electrode part 7 by spin coating.
[0026]
Next, the side surface 11 of the strip-shaped substrate 1 of FIG. 6B is subjected to a polishing process, and the end surface of the optical waveguide 4 is polished. At this time, since the top surfaces of the optical waveguide laminate 10 and the electrode portion 7 are protected by the coating material, no abrasives or foreign matters are attached or scratched.
[0027]
Next, the strip-shaped substrate 1 is cut out by dicing along the scribe line 51 to complete the optical waveguide device 100 (FIGS. 6C and 6D). At this time, since the resin layers of the upper and lower cladding layers 3 and 5 and the protective layer 9 are removed from the scribe line 51 as shown in FIG. 8A, the dicing blade cuts the Si substrate 1. . Therefore, a dicing blade suitable for cutting the Si substrate 1 can be used. Further, since the width of the scribe line 51 is wider than the width of the dicing blade, the dicing blade does not touch the resin layers such as the upper and lower cladding layers 3 and 5 as shown in FIG. Does not cause clogging. Further, since stress is not applied to the end surfaces of the upper and lower cladding layers 3 and 5 during dicing, there is no possibility that the upper and lower cladding layers 3 and 5 are peeled off from the cut portion. Therefore, the optical waveguide device 100 can be separated into pieces by cutting the substrate 1 efficiently and precisely. The coating material is peeled off by alcohol washing after separation.
[0028]
As a comparative example, the substrate 1 was diced into individual pieces in the same manner as in the present embodiment without forming the scribe line 51. A dicing blade suitable for cutting the Si substrate 1 was used. In this case, since the dicing blade cuts the resin layer such as the lower and upper cladding layers 3 and 5 and the substrate 1 simultaneously as shown in FIG. 8C, the dicing blade is clogged by the resin, The cutting surface was rough. In addition, a force is applied to the resin during cutting, so that a phenomenon that the end portions of the lower and upper clad layers 3 and 5 and the like easily peel off occurred.
[0029]
As described above, the optical waveguide device 100 manufactured in the present embodiment is an inorganic material in which the optical waveguide laminate 10 of the resin layer is mounted on the inorganic material substrate 1 and a line in which the resin is removed in advance in a band shape is formed. / Because it is a resin structure, even if it is an inorganic material / resin / inorganic material structure, by removing the resin layers such as the lower and upper clad layers 3 and 5 in advance in a band shape for the part cut out by dicing, Dicing can be performed smoothly and efficiently. Therefore, by using the manufacturing method of the present embodiment, it is possible to efficiently mass-produce resin-made high-precision optical waveguide devices.
[0030]
Further, in the present embodiment, a process of polishing the end face of the optical waveguide 4 is included, but by coating the upper surface of the optical waveguide laminate 10 and the upper surface of the electrode portion 7 with a coating material at the time of polishing, There is no possibility that foreign matter adheres to the optical waveguide laminate 10 and the electrode portion 7 or is damaged. If foreign matter adheres to or scratches on these, the propagation characteristics of the optical waveguide may be affected, or corrosion resistance may deteriorate from the scratches or foreign matter portions. In this embodiment, the top surface is clean and free from scratches. Therefore, optical waveguide devices with stable performance can be mass-produced.
[0031]
In the first embodiment, the electrode exposure line 50 is formed by dicing and the scribe line 51 is formed by dry etching or ashing. However, the electrode exposure line 50 and the scribe line 51 are dry etched using oxygen gas. Can also be formed at once. The other steps are the same as those in the first embodiment. Thus, by forming the electrode exposure line 50 and the scribe line 51 at the same time in the same process, the manufacturing process can be simplified compared to the first embodiment.
[0032]
Also, the scribe line 51 can be formed by dicing. In this case, when the width of the scribe line 51 is wide, the scribe line 51 can be formed by making cuts on both sides of the scribe line 51 and peeling off the lower and upper clad layers 3 and 5 in the same manner as the electrode exposure line 50. It is also possible to form the scribe line 51 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.
[0033]
The optical waveguide device 100 manufactured in the present embodiment described above has a high Tg and excellent heat resistance because all layers from the lower cladding layer 3 to the protective layer 9 are formed of polyimide. Therefore, the optical waveguide device of the present embodiment can maintain the propagation characteristics even when the temperature becomes high. In addition, since polyimide can withstand high temperature processes such as soldering, it is possible to solder another optical waveguide device, an electric circuit element, and a light emitting / receiving element on the optical waveguide device.
[0034]
The optical waveguide device 100 according to the present embodiment is an inorganic material / resin laminated structure in which a resinous optical waveguide laminate 10 is mounted on an inorganic material substrate 1, but the resin layer in the dicing portion is removed in advance. By using this method, dicing can be performed efficiently, and no force is applied to the resin layer during dicing. Therefore, the optical waveguide device having excellent optical characteristics of the present embodiment can be mass-produced at low cost.
[0035]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an optical waveguide device manufacturing method in which a resin optical waveguide is mounted on an inorganic material substrate, which is suitable for mass production. .
[Brief description of the drawings]
FIGS. 1A to 1C are cutaway perspective views showing a method of manufacturing a schematic optical waveguide device according to an embodiment of the present invention.
FIGS. 2D and 2E are cutaway perspective views showing a method for manufacturing a schematic optical waveguide device according to an embodiment of the present invention. FIGS.
FIG. 3 is a perspective view showing a configuration of a schematic optical waveguide device manufactured by the manufacturing method according to the embodiment of the present invention.
4 is a cross-sectional view taken along the line AA ′ of the optical waveguide device of FIG. 3. FIG.
FIG. 5 is a top view showing a process of forming an electrode exposure line 50 and a scribe line 51 in the method of manufacturing an optical waveguide device according to one embodiment of the present invention.
6A is a top view and a partial cross-sectional view of a substrate 1 showing a dicing position at which the wafer-like substrate 1 is cut into a strip shape in the method of manufacturing an optical waveguide device according to one embodiment of the present invention. FIG. (B) is the top view and sectional drawing which show the state of the strip-shaped board | substrate 1, (c) is a top view which shows the dicing position which makes the strip-shaped board | substrate 1 a piece, (d) FIG. 3 is a top view showing an individual optical waveguide device.
FIG. 7 is an explanatory diagram showing a step of applying a coating material onto a substrate 1 cut out in a strip shape in the method of manufacturing an optical waveguide device according to an embodiment of the present invention.
8A is a cross-sectional view taken along the line BB ′ showing a dicing step in the method of manufacturing an optical waveguide device according to the embodiment of the present invention, and FIG. 8B is a dicing blade as viewed from above. It is explanatory drawing which shows the positional relationship with the scribe line 51, (c) is explanatory drawing which shows the relationship between the dicing blade in case there is no scribe line 51 of a comparative example, and a resin layer.
[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

Claims (10)

A method of manufacturing an optical waveguide device comprising an optical waveguide laminate on an inorganic material substrate,
A first step of forming a lower clad layer with a resin on the entire top surface of an inorganic material substrate having a plurality of electrode portions formed vertically and horizontally ;
A second step of forming a plurality of resin-made optical waveguides on the lower cladding layer in a vertical and horizontal direction corresponding to the electrode parts ;
A third step of forming an upper clad layer covering the entire top surface of the substrate with a resin, and the electrode portions and the optical waveguide laminate arranged vertically and horizontally by the first to third steps, Formed on the substrate,
Further, by cutting the substrate for each of the electrode portions and the optical waveguide laminates are arranged in the vertical and horizontal, and a fourth step of disconnecting the individual the electrode portion and the optical waveguide laminate,
Between the third step and the fourth step, the lower portion of the boundary between the electrode portion and the optical waveguide laminate along the direction in which the electrode portion and the optical waveguide are arranged on the substrate The clad layer and the upper clad layer are removed from the substrate by dicing, and the lower clad layer and the upper clad layer at the boundary between the adjacent optical waveguides are removed from the substrate in a band shape by dry etching or ashing. An optical waveguide device manufacturing method comprising: performing a removing step, wherein the fourth step includes a step of cutting the substrate at a position removed in a strip shape in the removing step.   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 removed in the removing step is determined by the thickness of the dicing blade. A method of manufacturing an optical waveguide device characterized by being wide.   3. The method of manufacturing an optical waveguide device according to claim 2, wherein the cutting at the position removed in the strip shape in the fourth step is performed so that the dicing blade does not contact the lower and upper clad layers. An optical waveguide device manufacturing method characterized by the above. A method of manufacturing an optical waveguide device comprising an optical waveguide laminate on an inorganic material substrate,
A first step of forming a lower clad layer with a resin on the entire top surface of the inorganic material substrate;
A second step of forming a plurality of resin-made optical waveguides arranged vertically and horizontally on the lower cladding layer;
A third step of forming an upper clad layer covering the entire upper surface of the substrate with a resin, and the optical waveguide laminates arranged vertically and horizontally by the first to third steps on the substrate. Formed,
And a fourth step of separating each of the optical waveguide laminates by cutting the substrate for each of the optical waveguide laminates arranged in the vertical and horizontal directions,
Between the third step and the fourth step, along the direction in which the optical waveguides are arranged on the substrate, the lower cladding layer and the upper portion at the boundary between the adjacent optical waveguides and the optical waveguides A removal step of removing the clad layer from the substrate in a strip shape is performed, and the fourth step includes a step of cutting the substrate at a position removed in the strip shape in the removal step,
In the fourth step, the cutting is performed by dicing using a dicing blade, and the width of the strip portion removed in the removing step is wider than the thickness of the dicing blade,
The removing step is performed by cutting the lower and upper clad layers of the strip-like portion to be removed by dicing using a dicing blade and then peeling the lower and upper clad layers from the front substrate. An optical waveguide device manufacturing method characterized by the above.   5. The method of 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, and an inorganic material cutting blade is used as the dicing blade used in the fourth step. An optical waveguide device manufacturing method characterized by the above.   3. The method of manufacturing an optical waveguide device according to claim 1, wherein the removing step is performed by dry etching or ashing.   The method for manufacturing an optical waveguide device according to any one of claims 1 to 6, wherein the inorganic material other than resin to be cut is silicon or glass. An optical waveguide device having an inorganic material substrate and a resin optical waveguide laminate provided on the inorganic material substrate,
The inorganic material substrate has a cut side surface in the cut longitudinal direction,
The optical waveguide laminate possess the longitudinal direction longitudinal sides retracted to strip from the cutting side surface of the inorganic material substrate to expose the inorganic material substrate,
The side surface withdrawn into the band shape is formed by cutting the lower clad layer and the upper clad layer of the optical waveguide laminate with a dicing blade and peeling the lower clad layer and the upper clad layer from the substrate. An optical waveguide device characterized in that the width of the recessed portion is wider than the thickness of the dicing blade .   The optical waveguide device according to claim 8, wherein the cutting side surface of the inorganic material substrate is formed by dicing using a blade for cutting an inorganic material.   10. The optical waveguide device according to claim 8, wherein the side surface into which the optical waveguide laminate is drawn is formed by dicing using a blade for resin cutting.

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