JPH1164675A - Production of optical coupler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to produce an optical coupler which is excellent in productivity and has a stable operating characteristic. SOLUTION: A dielectric block subjected to a plasma treatment on the adhesive surface is adhered by a photosetting adhesive 15 to a gap layer 13 on an optical waveguide layer 12 likewise subjected to the plasma treatment on the adhesive surface. The adhesive 15 is impregnated into the spacing between the optical waveguide layer 12 parted by a previously patterned photoresist layer 20 and the dielectric block layer and is then cured. The upper surface of the dielectric block is pressed and fixed by a metallic probe at the time of impregnation of the adhesive 15. The upper surface of the dielectric block is optically polished to allow the observation of the way of the impregnation of the adhesive 15. The photoresist layer 20 is thereafter removed by executing a dicing treatment, by which individual element chips are obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical coupler used to input light to an optical waveguide device.

[0002]

2. Description of the Related Art The light input to an optical coupler used for inputting light to an optical waveguide element is, for example, a prism coupler formed by pressing a prism against an optical waveguide. When light enters near the boundary between the portion and the non-portion (hereinafter, referred to as “prism edge”), the light that has tunneled into the optical waveguide from a portion with the prism is converted into a portion without the prism. Utilizes the phenomenon that light propagates without going outside the optical waveguide.

However, in such a method, the prism coupler cannot be integrated with the optical waveguide device. Then, a method of bonding the prism onto the optical waveguide with an adhesive has been proposed (for example, Japanese Patent Application Laid-Open No. H4-15950)
No. 3). Specifically, FIGS. 21A and 21B
As shown in FIG. 1, an equivalent gap layer 1 having a lower refractive index than the optical waveguide layer 12 is provided on the optical waveguide layer 12 of the optical waveguide element.
3 is formed, and a prism 14 is bonded on the equivalent gap layer 13.

More specifically, in the optical waveguide device shown in the schematic cross-sectional view of FIG. 21A, an optical waveguide layer 12 is formed on a substrate 11, and the optical waveguide layer 12 is further formed thereon. An equivalent gap layer 13 having a lower refractive index is formed. On the equivalent gap layer 13, a prism 14 made of a dielectric is provided with a photo-curing adhesive 15.
It is fixed by. The prism 14 and the photo-curable adhesive 15 have a higher refractive index than the optical waveguide layer 12.
In order to fix the prism 14 to the equivalent gap layer 13, for example, a light-curing adhesive 15 is applied to the adhesive surface of the prism 14, the applied surface is pressed against the equivalent gap layer 13, and light is emitted from the slope of the prism 14. Irradiation may cure the adhesive 15.

In this case, the light incident on the prism 14 is
The light passes through the equivalent gap layer 13 in a tunnel effect from the bonding portion, enters the optical waveguide layer 12, and propagates inside the optical waveguide layer 12. However, as shown in the schematic enlarged perspective view of FIG. 21B, the edge portion e of the adhesive 15 is not straight due to the surface tension of the adhesive 15. Therefore, even if an attempt is made to optimize the incident position of the incident light spot in the major axis direction (defined by the distance from the edge of the adhesive to the center of the incident light spot), the coupling efficiency changes in the minor axis direction of the incident light spot. Therefore, it is difficult to accurately determine the incident position of the light at which the coupling efficiency is maximized. Further, even if such an incident position is set at a certain position, there is a problem that the maximum coupling efficiency cannot be obtained at that position.

In order to solve this problem, FIG.
And the configuration of the optical waveguide element as shown in FIG.

More specifically, in the optical waveguide device shown in the schematic sectional view of FIG. 22A, an optical waveguide layer 12 is formed on a substrate 11, and a gap layer 13 is further formed thereon. Have been. On the gap layer 13, a light-shielding layer 16 (having an opening A) formed of a dielectric thin film having a lower refractive index than the optical waveguide layer 12 is formed. The prism 14 is fixed at a position corresponding to the opening A of the light shielding layer 16 by a photo-curing adhesive 15.
The prism 14 is formed by applying a sufficient amount of a photo-curing adhesive 15 to the opening A of the light-shielding layer 16, pressing the prism 14 on the application surface, and irradiating light through the prism 14 to the adhesive 15. May be cured.

In such a configuration, as shown in a schematic enlarged perspective view of FIG. 22B, the light shielding layer 16 forms a linear edge E at the bonding portion, and a stable coupling efficiency can be obtained. Can be

[0009] The term "edge straight line" used herein means:
Among the lines of intersection formed by the side surfaces of the adhesive 15 intersecting substantially perpendicularly to the gap layer 13, the lines of intersection that are perpendicular to the optical axis and are far from the light incident surface (the inclined surface of the prism 14) are indicated. . The requirement for this linearity is determined relatively to the major axis of the incident light spot. For example, for incident light having an incident light spot having a major axis of about 10 μm, about ±
With a displacement of 2.5 μm, the coupling efficiency drops to 90% of the maximum efficiency. From this, the “straight line” referred to here is “a straight line having a deviation from the center line of about ± 0.5 μm or less, as obtained by photolithography”.
Means

[0010]

In recent years, optical elements tend to be smaller and lighter, and accordingly, the prism 14 also has a size of 1 mm or less.
Considering this point, it is difficult to adjust the amount of the adhesive 15 to be filled in the opening A by the above-described conventional method described with reference to FIGS.

If the amount of the adhesive 15 is too large, the excess adhesive 15 overflows to the side surface of the prism 14 and reaches the component (not shown) holding the prism 14. On the other hand, when the amount of the adhesive 15 is small, air bubbles may remain inside the opening A. Furthermore, after the adhesive 15 is cured, the prism 14 continues to receive the contraction stress of the adhesive 15 while being supported by the light shielding layer 16, and there is a problem from the viewpoint of maintaining reliability. In some cases, a fatal phenomenon that the prism is peeled off as soon as the adhesive 15 is cured may occur.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above problems, and has as its object to provide a method for manufacturing an optical coupler capable of manufacturing an optical coupler having excellent productivity and stable operation characteristics. It is to provide.

[0013]

According to one aspect of the present invention, a step of providing an optical waveguide layer and a gap layer on a substrate, and patterning a photoresist layer provided on the gap layer into a predetermined pattern. A step of bonding a dielectric block with a photo-curable adhesive injected into the predetermined pattern; a step of dicing the substrate into individual element chips; and a step of dicing the individual element chips. And a step of removing the photoresist layer from the above. The predetermined pattern of the photoresist layer is a T-shaped pattern, and the T-shaped lateral length of the T-shaped pattern is longer than the lateral length of the bonding surface of the dielectric block; The vertical length of the character is longer than the vertical length of the adhesive surface of the dielectric block, the width of the horizontal line forming the T-shape is smaller than the vertical length of the dielectric block, The thickness of the vertical line forming the T-shape is smaller than the horizontal length of the dielectric block, and the photocurable adhesive is injected from an adhesive injection portion provided at the tip of the vertical line of the T-shape. I do. The above object is achieved by such features.

According to another aspect of the present invention, a step of providing an optical waveguide layer and a gap layer on a substrate, a step of patterning a photoresist layer provided on the gap layer into a predetermined pattern, Bonding a rod-shaped dielectric block with a photo-curable adhesive injected into a predetermined pattern, simultaneously dicing the substrate and the rod-shaped dielectric block into individual element chips, Removing the photoresist layer from the device chip of (1). The predetermined pattern of the photoresist layer is a substantially T-shaped pattern, and the length of the substantially T-shaped pattern in the lateral direction is substantially equal to the lateral direction of the bonding surface per chip of the rod-shaped dielectric block. , The length of the substantially T-shaped portion in the vertical direction is longer than the length of the sticking surface of the rod-shaped dielectric block per chip in the vertical direction, and the thickness of the horizontal line forming the substantially T-shaped portion Is smaller than the length of the rod-shaped dielectric block in the vertical direction.
The thickness of the vertical line forming the character is smaller than the horizontal length per chip of the rod-shaped dielectric block, and a gas vent portion is provided at the tip of the horizontal line of the substantially T-shape. The photocurable adhesive is injected from an adhesive injection part provided at the tip of the substantially T-shaped vertical line. The above object is achieved by such features.

In one embodiment, of the vertical lines of the T-shaped pattern or the substantially T-shaped pattern provided on the photoresist layer, when the dielectric block or the rod-shaped dielectric block is arranged, The width of a portion not covered by the body block or the rod-shaped dielectric block is smaller than the width of the portion covered by the dielectric block or the rod-shaped dielectric block.

When the dielectric block or the rod-shaped dielectric block is bonded, the dielectric block or the rod-shaped dielectric block may be pressed and fixed using the upper surface of the dielectric block or the rod-shaped dielectric block.
Preferably, the pressure fixing using the upper surface of the dielectric block or the rod-shaped dielectric block is performed by a probe sufficiently smaller than the size of the dielectric block or the rod-shaped dielectric block.

Preferably, an upper surface of the dielectric block or the rod-shaped dielectric block is an optically polished surface.

Preferably, the method further includes a step of subjecting the bonded surface of the dielectric block or the rod-shaped dielectric block to a plasma treatment prior to the bonding of the dielectric block or the rod-shaped dielectric block. Alternatively, prior to bonding the dielectric block or the rod-shaped dielectric block,
The method further includes a step of plasma-treating the bonding surface of the dielectric block or the rod-shaped dielectric block and the bonding surface of the gap layer.

Prior to the dicing treatment of the substrate, the method further includes a step of removing the photoresist layer at a portion corresponding to a portion to be diced on the substrate with a width wider than a width of a blade used at the time of dicing. You may.

In one embodiment, the dielectric block or the rod-shaped dielectric block is a trapezoidal prism.

In another embodiment, the dielectric block or the rod-shaped dielectric block is a parallelogram prism.

In still another embodiment, the dielectric block or the rod-shaped dielectric block is an inverted trapezoidal prism.

In still another embodiment, the dielectric block or the rod-shaped dielectric block is a beam splitter.

The operation of the present invention will be described below.

According to the present invention, the dielectric block separated from the gap layer on the optical waveguide layer by the patterned photoresist is adhered by the photo-curing adhesive injected into the photoresist pattern. Then, in a method of manufacturing a photodetector for removing the photoresist after dicing the element, the support of the dielectric block is a T-shaped photoresist pattern, and the lateral length of the T-shaped pattern is defined as the width of the dielectric block. The length of the bonding surface is longer than the length in the horizontal direction, the length in the vertical direction is sufficiently longer than the length in the vertical direction of the bonding surface of the dielectric block, and the width of the horizontal line forming the T-shape is set to the thickness of the dielectric block. , And the thickness of the vertical line is smaller than the horizontal length of the dielectric block, and the light-curing type bonding is performed from the adhesive injection portion provided at the end of the T-shaped vertical line. To be injected. Thereby, an appropriate amount of adhesive can be efficiently filled.

Alternatively, a rod-shaped dielectric block separated from the gap layer on the optical waveguide layer by a patterned photoresist is adhered by a photo-curable adhesive injected into the photoresist pattern, In a method of manufacturing a photodetector for removing a photoresist after dicing an element, the support of a rod-shaped dielectric block is substantially T
A substantially T-shaped photoresist pattern having a horizontal length shorter than a horizontal length of an adhesive surface per one chip of the dielectric block, and a vertical length of the dielectric block being bonded to the dielectric block. Longer than the vertical length of the surface,
In addition, the thickness of the horizontal line forming the substantially T-shape is made smaller than the vertical length of the rod-shaped dielectric block, and the thickness of the vertical line is made smaller than the horizontal length per chip of the rod-shaped dielectric block. When the bar-shaped dielectric block is disposed at both upper ends of the horizontal line, a punch-out portion is provided at a portion protruding without being covered by the bar-shaped dielectric block, and an adhesive injection provided at an end of the substantially T-shaped vertical line is provided. The photocurable adhesive is injected from the part. Thereby, an appropriate amount of the adhesive can be efficiently filled.

Further, the T formed on the photoresist
In the vertical line of the letter or the substantially T-shaped pattern, the line width of a portion protruding without being hidden when the dielectric block or the rod-shaped dielectric block is arranged is set below the dielectric block or the rod-shaped dielectric block. By making the line width smaller than the line width of the hidden portion, an appropriate amount of adhesive can be more efficiently filled.

Further, if the bonding surface is pressed and fixed using the upper surface of the dielectric block or the rod-shaped dielectric block, the prism does not shift from the position adjustment to the completion of the bonding.

If the dielectric block or the rod-shaped dielectric block is pressed and fixed with a probe sufficiently thinner than the above, the influence of shadow upon light irradiation can be suppressed to the minimum.

If the upper surface of the dielectric block or the rod-shaped dielectric block is an optically polished surface, the filling of the adhesive can be observed with a microscope through these surfaces, so that adjustment and confirmation of the filling amount are facilitated. In addition, the adhesive can be sufficiently irradiated with light.

Further, by subjecting the bonding surface of the dielectric block or the rod-shaped dielectric block, which is supported only by the cured adhesive layer, to plasma treatment in advance, the adhesive force is increased, and these are not peeled off.

In addition, by pre-plasma-treating both the adhesive surface of the dielectric block or the rod-shaped dielectric block and the adhesive surface of the gap layer surface, the adhesive force is further increased, and these are not peeled off.

Further, before dicing the substrate into individual element chips, by removing the photoresist in a portion where the blade passes, the blade may be damaged during dicing or the cutting speed may be reduced. Can be prevented.

When the dielectric block or the rod-shaped dielectric block is a trapezoidal prism, incident light can be made to be incident perpendicularly on the slope.

Alternatively, when the dielectric block or the rod-shaped dielectric block is a parallelogram prism, the fabrication is facilitated, an inexpensive optical coupler is obtained, and the cost can be reduced.

Alternatively, if the dielectric block or the rod-shaped dielectric block is an inverted trapezoidal prism, incident light can be made to be perpendicularly incident on the substrate.

Further, if the above-mentioned dielectric block or rod-like dielectric block is used as a beam splitter, it is not affected by contamination on the reflection surface.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a method for manufacturing an optical coupler according to an embodiment of the present invention, a trapezoidal prism whose upper surface is optically polished is supported by a T-shaped patterned photoresist layer.
A photocurable adhesive is injected into the resist-removed portion of the T-shaped resist pattern from an adhesive injection portion provided on the side opposite to the optical coupling portion. The prism is held by vacuum suction on the side of the prism when adjusting the fixing position, while it is fixed to the photoresist surface by pressing the top of the prism with a thin metal probe when injecting adhesive. Is done. The injection amount of the adhesive is adjusted while observing the bonding surface with a microscope through the optically polished surface on the upper surface of the trapezoidal prism, and the impregnation is stopped by light irradiation. Further, the bonding surface between the prism and the gap layer to be used is subjected to plasma processing in advance.

According to the above-described manufacturing method, the prism is fixed to a predetermined position when the trapezoidal prism is bonded by pressing the optically polished upper surface of the prism with a metal probe, so that the adhesive at the time of injecting the adhesive can be obtained. The displacement of the prism due to the impact or the surface tension of the adhesive is suppressed, and the microscope observation of the bonding surface is facilitated. Also, the amount of adhesive can be easily adjusted while observing the microscope from the top of the prism,
Excessive adhesive may overflow onto the side of the prism and spill over to the part holding the prism, or
The problem of bubbles remaining due to lack of adhesive,
Does not occur.

Further, after the adhesive is cured, the prism is supported only by the adhesive layer, and the adhesive surface between the prism and the gap layer is plasma-treated, so that the prism does not peel off.

Hereinafter, a specific embodiment of the method for manufacturing an optical coupler of the present invention will be described in more detail with reference to the accompanying drawings. In the drawings referred to in the following description,
The same components are denoted by the same reference numerals, and redundant description may be omitted for simplification.

First, a method for manufacturing an optical coupler according to an embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, an optical waveguide layer 12 and a gap layer 13 are laminated on a dielectric substrate 11 or a Si substrate 11 having a dielectric layer formed on the upper surface thereof. Lattice pattern 1 as shown
9 is formed. Specifically, for example, the coated and baked photoresist is subjected to contact exposure using a photomask, and is developed using a dedicated developing solution, so that the photoresist layer 2 is formed.
A predetermined lattice pattern 19 is formed for 0.

In such a forming process, a portion of the photoresist layer 20 through which the blade passes at the time of dicing of an element chip performed in a later step is removed with a line width t larger than the thickness of the blade, thereby forming a lattice-like shape. A pattern 19 is formed. The line width t is set to about 300 μm, for example, when the thickness of the used blade is about 200 μm. Accordingly, it is possible to prevent the life of the blade from being shortened and the cutting speed from being reduced due to the photoresist being caught in the blade.

Each film can be composed of, for example, the following materials and thicknesses: layer material thickness dielectric layer CVD-SiO ₂ film about 4 μm optical waveguide layer Corning # 7059 RF sputtering film of glass about 0 0.6 μm gap layer SiO ₂ RF sputtering film about 0.1 μm Photoresist layer After HMDS treatment, Tokyo Ohka Kogyo PMER-AR900 two-layer coating about 40 μm

Next, as shown in FIG. 2, a T-shaped pattern 21 is exposed to the photoresist layer 20 on which the lattice pattern 19 has been formed. Specifically, for example, contact exposure is performed using a photomask. In this case, the photoresist is positive.

In the T-shaped pattern 21, the horizontal length of the T-shape is longer than the horizontal length of the prism bonding surface, and the vertical length is sufficiently longer than the vertical length of the prism bonding surface. The thickness of the horizontal line forming the T-shape is smaller than the length of the prism in the vertical direction, and the thickness of the vertical line is smaller than the length of the prism in the horizontal direction. For example, for a prism having a bonding surface of about 0.5 mm × about 0.5 mm square, the T-shaped pattern 21 has a T-shaped horizontal length of about 0.7 mm and a vertical length of about 0.7 mm. Approximately 1 mm, vertical and horizontal line thickness is approximately 0.3 mm
It is.

By patterning the photoresist layer 20 into such a T-shaped pattern 21, the prism can be stably supported, and an adhesive injection portion and a gas vent can be provided. The fact that the vertical length of the T-shaped pattern 21 is sufficiently longer than the vertical length of the prism means that an injection portion and an introduction portion for impregnating the photocurable adhesive in a later process are formed. It is important.

Next, as shown in FIG. 3, the substrate after the exposure is placed under ambient conditions (for example, under irradiation of a yellow light) so that the photoresist does not react, and the photoresist is formed in a grid pattern. Dicing the removed part,
It is cut into individual element chips 22.

Subsequently, as shown in FIG. 4, the T-shaped exposed portion of the photoresist layer 20 (T-shaped pattern 21 shown in FIG. 3) is developed using a dedicated developing solution, A photoresist pattern 23 is formed. The development of this portion is performed after the dicing step in order to avoid contamination of the surface relating to the adhesion of the prism.

FIGS. 5 to 7 show a method of bonding the prism 14 to the element chip 22 processed as described above.

First, as shown in FIG. 5, an element chip 22 having a T-shaped photoresist pattern 23 formed thereon is formed.
Next, the prism 14 is mounted. Part of the T-shaped photoresist pattern 23 functions as an adhesive injection section 23A in the subsequent steps. Specifically, the adhesive injection portion 23A corresponds to the slope side of the prism 14, that is, a portion of the T-shaped vertical line that is not covered by the prism 14. Therefore, the process of injecting the adhesive 15 from the adhesive injecting portion 23A does not affect the optical coupling portion on the opposite side (corresponding to the portion indicated by reference numeral C in FIG. 8).

The prism 14 has a very small size. The relative position between the element chip 22 and the prism 14 is adjusted while holding the side surface of the prism 14 by suction using a thin tube 24 (preferably made of metal). Further, a surface related to the adhesion between the prism 14 and the gap layer 13 has been subjected to plasma processing in advance. As a result, dirt remaining on the surface (such as wax mainly used for producing the prism) is removed, and the surface of the prism 14 has irregularities at the atomic level, so that the adhesiveness is remarkably improved.

The prism is made of, for example, a glass material (SK5), and its size is, for example, about 0.5 mm in height × about 0.5 mm in width. In the plasma processing, for example, processing is performed for about 30 seconds with O ₂ plasma (RF power of about 200 W) at a pressure of about 5 Pa.

Next, as shown in FIG.
A thin tube (not shown in FIG. 6) is separated from the prism 14 mounted on the prism 14, and the prism 14 is replaced with a thin probe 25 (preferably made of metal, hereinafter also referred to as a "metal probe 25"). Press and fix. For that purpose, the upper surface of the prism 14 must be flat, and specifically, for example, a trapezoidal prism 14 is required.

The metal probe 25 must be sufficiently thin with respect to the trapezoidal prism 14 in order to minimize the shadow of the probe 25 caused by the light irradiated when the adhesive 15 is cured. For example, about 0.5
For a prism 14 having a size of mm square, the thickness is about 0.1 mm.
A 2 mm tungsten probe 25 is used. The tip of this probe 25 is about 30 μm thick.
It has been processed to be thinner.

In this state, when the photocurable adhesive 15 is injected from the adhesive injection section 23A using the second thin tube 26,
While extruding the gas in the gap (T-shaped photoresist pattern 23) between the prism 14 and the element chip 22 from the vent 23B, the photocurable adhesive 15 flows into the T-shaped photoresist pattern 23. Go. After the necessary amount of the photo-curable adhesive 15 is injected, the second thin tube 26 is quickly moved away from the element chip 22. Here, the prism 14 is fixed by the metal probe 25 to the second thin tube 2.
6 may hit the trapezoidal prism 14 or the light-curing adhesive 1
5 due to the surface tension of the trapezoidal prism 14
In order to prevent the position from being shifted.

Since the upper surface of the trapezoidal prism 14 is optically polished, the flow of the photo-curable adhesive 15 can be observed with a microscope. After confirming with a microscope that the adhesive 15 has sufficiently flowed in, light irradiation for curing the adhesive 15 is performed. For example, if the photocurable adhesive 15 is an ultraviolet curable adhesive, the light to be irradiated is ultraviolet light. Irradiation is sufficiently performed from all directions so as to prevent uneven curing. The optically polished upper surface of the trapezoidal prism 14 can efficiently guide the irradiated light to the adhesive 15.

After the curing is completed, the photoresist layer 20 is removed by a registry remover (not shown) as shown in FIG. This registry remover does not attack the photocurable adhesive 15 after curing. For example, Shipley 1165 Remover is suitable.

Through the above steps, an optical coupler is manufactured.

As is apparent from FIG. 7, the optical coupler has a structure in which the prism 14 is attached on the gap layer 13 with only the adhesive layer 15. Adhesive 1
After the curing of 5, the prism 14 is supported only by the adhesive 15, and since the bonding surface of the prism 14 is plasma-treated, the prism 14 does not peel off.

FIG. 8 is a sectional view showing an application example of the optical coupler of the present invention manufactured as described above.

The dielectric layer 11B is formed on the Si substrate 11A on which the light detecting section 30 (shown in a simplified form) is formed so as to gradually become thinner as approaching the light detecting section 30. The Si substrate 11A and the dielectric layer 11B
This corresponds to the substrate 11 in FIGS. Further, the optical waveguide layer 12 and the gap layer 13 are laminated on the substrate 11, thereby forming a tapered waveguide type photodetector as a whole.

The incident light L passes through the prism 14 and the adhesive layer 1.
5 and is coupled to the optical waveguide layer 12 at the optical coupling section C,
The light is guided to the light detection unit 30 while propagating through the tapered portion T with low loss, and is photoelectrically converted.

In the method for manufacturing an optical coupler described above,
After dicing the substrate 11 into individual element chips 22, a T-shaped pattern 23 in the photoresist layer 22 is formed.
Is performed, and the prism 14 is bonded. Alternatively, as described below with reference to FIGS. 9 and 10,
It is also possible to perform dicing after bonding the prism 14.

In this case, as shown in FIG. 9, both the T-shaped photoresist pattern 23 and the lattice pattern 19 are formed on the photoresist layer 20. Specifically, for example, the photoresist layer 20 is formed using the same photomask.
By performing contact exposure and development processing on
-Shaped photoresist pattern 23 and lattice pattern 1
9 are formed simultaneously. As the photoresist layer 20,
It is also possible to use a negative photoresist.

As in the above-described example, the T-shaped photoresist 23 has a lateral length of the T-shaped longer than a lateral length of the prism bonding surface and a vertical length of the prism bonding surface. The length of the horizontal line forming the T-shape is thinner than the vertical length of the prism, and the thickness of the vertical line is thinner than the horizontal length of the prism. For example,
For a prism having a square bonding surface of about 0.5 mm × about 0.5 mm, the lateral length of the T-shape is about 0.7 m.
m, vertical length 1 mm, vertical and horizontal line thickness 0.3 m
m.

The line width of the grid pattern 19 is about 300 μm, for example, when the thickness of the blade to be used is about 200 μm.

Subsequently, as shown in FIG. 10, the trapezoidal prism 14 is bonded with a photo-curing adhesive 15. The method of holding, fixing, and bonding the prism 14 may be the method described with reference to FIGS. The curing of the adhesive 15 is also the same. After the curing, the substrate 11 is diced into chips, and the photoresist layer 20 is removed by a registry remover as described above, whereby the same light as that shown in FIG. A coupler is made.

After the adhesive is cured, the prism 14 is moved to the adhesive layer 1
5 is the same as in the above-described example, since the adhesive surface of the prism 14 is plasma-treated and the prism 14 does not peel off.

A method of manufacturing an optical coupler according to still another embodiment of the present invention will be described with reference to FIGS.

The state shown in FIG. 11 differs from the state shown in FIG. 9 in the shape of the substantially T-shaped pattern 23 ′ formed on the photoresist layer 20. Specifically, the line width of a portion of the T-shaped vertical line that is not covered by the prism 14 when the prism 14 is arranged is smaller than the line width of a portion hidden under the prism 14. This part
It functions as an adhesive introduction part 23C. Thereby, the adhesive 15 dropped on the adhesive injection section 23A 'can be efficiently flowed under the prism 14.

In general, due to its wettability, the adhesive 15 spreads faster on the wall surface of the pattern of the photoresist layer 20 than on the surface of the gap layer 13. For this reason, the inflow speed can be increased by reducing the exposure of the gap layer 13 at the portion where the adhesive 15 spreads.

Adhesive Injection Portion 23A 'and Adhesive Injection Portion 2
Since the portion 3C is covered with the adhesive 15, it is better not to manufacture a semiconductor element or an optical waveguide element in this portion. In order to cut and remove this portion by dicing, the photoresist layer 20 is provided with another lattice pattern 19 '.

After the shape shown in FIG. 11 is formed, subsequently, as shown in FIG. 12, a prism 14 is arranged and bonded with a photo-curing adhesive 15. The method of holding, fixing, and bonding the prism 14 may be the method described with reference to FIGS. The same applies to the curing of the adhesive 15. After the curing, the substrate 11 is diced into chips along the lattice patterns 19 and 19 ′, and the photoresist layer 20 is removed by the registry remover as described above. FIG.
The optical coupler shown in FIG.

After the adhesive 15 is cured, the prism 14 is supported only by the adhesive layer 15 and the prism 14 is not peeled off because the bonding surface of the prism 14 is plasma-treated. The same is true.

A method of manufacturing an optical coupler according to still another embodiment of the present invention will be described with reference to FIGS.

In the above-described embodiment, the pre-processed prism 14 is bonded to each element chip 22.
In the method described below, the rod-shaped prism 14 ′ is
1 and further, the substrate 11 and the rod-shaped prism 14 'are simultaneously diced to obtain individual optical couplers. By doing so, the prism corresponding to several tens of chips can be arranged at a time, so that the positional accuracy and work efficiency are improved.

In this case, however, the T-shaped photoresist pattern 23 described above with reference to FIG. 9 or FIG.
When the rod-shaped prism 14 'is to be adhered by using the rod-shaped prism 14', the gas venting portion 23B is covered with the rod-shaped prism 14 ', so that a sufficient function cannot be exhibited. Therefore, as shown in FIG. 14, gas vents 23B 'are formed at both upper ends of the horizontal line of the substantially T-shaped pattern 23'. by this,
The cutout portion 23B 'functions sufficiently without being covered by the rod-shaped prism 14', and the adhesive 15 can flow in efficiently.

After the shape shown in FIG. 14 is formed, subsequently, as shown in FIG. 15, a rod-shaped prism 14 ′ which has been subjected to a plasma treatment is disposed on the substrate, and the light-curing adhesive 15 is used. Glue.

The method of holding, fixing and bonding the rod-shaped prism 14 'may be the method described with reference to FIGS. That is, as shown in FIG. 16, a thin tube (not shown in FIG. 16) is separated from the rod-shaped prism 14 'mounted on the element chip 22, and the rod-shaped prism 14' is pressed and fixed with a thin metal probe 25 instead. I do. For this purpose, the upper surface of the rod-shaped prism 14 'must be flat, and specifically, for example, a trapezoidal rod-shaped prism 14' is required.
The metal probe 25 must be sufficiently thin with respect to the rod-shaped prism 14 'in order to minimize the shadow of the probe 25 caused by the light irradiated when the adhesive 15 is cured. For example, for a prism 14 'having a size of about 0.5 mm square, a tungsten probe 25 having a thickness of about 0.2 mm is used. The tip of this probe 25 is machined so that the thickness is further reduced to about 30 μm. Also, the rod-shaped prism 14 '
Depending on the length, it is effective to use a plurality of the metal probes 25 or appropriately change the shape.

The rod-like prism 1 is formed by the thin metal probe 25.
When the photo-curable adhesive 15 is injected from the adhesive injection portion 23A 'using the second thin tube 26 while the 4' is pressed and fixed, the gap between the rod-shaped prism 14 'and the element chip 22 (photoresist Degassing part 2 of pattern 23 ')
While extruding from 3B ', the photo-curable adhesive 15 flows into the photoresist pattern 23'. After the required amount of the photo-curable adhesive 15 has been injected, the second thin tube 26
Is quickly moved away from the element chip 22. Here, the rod-shaped prism 14 ′ is fixed by the metal probe 25.
This is for preventing the position of the rod-shaped prism 14 'from shifting due to the second thin tube 26 hitting the rod-shaped prism 14' or the surface tension of the photo-curing adhesive 15 as a cause.

Since the upper surface of the rod-shaped prism 14 'is optically polished, the flow of the photo-curable adhesive 15 can be observed with a microscope. After confirming with a microscope that the adhesive 15 has sufficiently flowed in, light irradiation for curing the adhesive 15 is performed. For example, if the photocurable adhesive 15 is an ultraviolet curable adhesive, the light to be irradiated is ultraviolet light. Irradiation is sufficiently performed from all directions so as to prevent uneven curing. The optically polished upper surface of the rod-shaped prism 14 ′ can efficiently guide the irradiated light to the adhesive 15.

After the curing is completed, the substrate 11 is diced into chips along the lattice patterns 19 and 19 ', and the photoresist layer 20 is removed by a registry remover as described above. The optical coupler shown is made. After the adhesive 15 is cured, the prism 14
Is supported only by the adhesive layer 15 and the prism 1
Since the bonding surface of No. 4 is plasma-treated, the prism 1
No peeling of No. 4 occurs as in the example described above.

In FIGS. 7, 8, 13, 16 and 17 already described, the prism 14 or the rod-shaped prism 1 is used.
4 'is a trapezoidal prism. The trapezoidal prism can make incident light perpendicular to the slope by designing the angle of the slope. In the case of normal incidence, the design of the optical coupler is simplified because the refraction of the incident light does not need to be considered.

Here, in the optical coupler of the present invention, since the edge formed on the adhesive layer 15 becomes the optical coupling portion,
The edge of the prism is not important.

The surface farther from the inclined surface of the prism (the surface A in FIG. 18) does not need to be perpendicular to the bottom surface, and may be, for example, a parallelogram prism 27 as shown in FIG. The incident light L perpendicularly incident on the slope is guided to the edge formed on the adhesive layer 15 and is coupled to the optical waveguide layer 12. In this example, the surface A through which light does not pass need not be optically polished, and may be a cut surface. Such a parallelogram prism 27 can be manufactured inexpensively because it is sufficient to cut out a dielectric plate in parallel and grind only a necessary surface.

In FIG. 19, an inverted trapezoidal prism 28 is used. In this case, the incident light L is guided to the edge formed on the adhesive layer 15 after being reflected on the slope, and further coupled to the optical waveguide layer 12. The incident light L can be made perpendicular to the upper surface (or the element substrate) of the inverted trapezoidal prism 28, so that the configuration of the entire optical system including the photodetector can be made small and simple. .

Further, in FIG. 20, the beam splitter 2
9 is used. In this case, the incident light L is reflected by the reflection surface K formed inside, is guided to the edge formed on the adhesive layer 15, and further couples to the optical waveguide layer 12. By using the beam splitter 29, it is possible to suppress a decrease in coupling efficiency due to dirt on the reflection surface as compared with the case where the inverted trapezoidal prism 28 is used.

The parallelogram prism 2 as described above
7. Even when the inverted trapezoidal prism 28 and the beam splitter 29 are used, as in the case of the trapezoidal prism 14, the rod-shaped
It is also possible to simultaneously dice and process the rod-shaped prism.

[0091]

As described above, according to the present invention, the dielectric block separated from the gap layer on the optical waveguide layer by the patterned photoresist is injected into the photoresist pattern. In a method for manufacturing a photodetector in which a photoresist is removed after bonding with a curable adhesive and subsequently dicing the element, a T-shaped photoresist pattern is used as a support for the dielectric block, and a lateral direction of the T-shaped pattern is used. The length is longer than the horizontal length of the bonding surface of the dielectric block, the vertical length is sufficiently longer than the vertical length of the bonding surface of the dielectric block, and a horizontal line forming a T-shape The thickness of the vertical line is thinner than the length of the dielectric block in the vertical direction, the thickness of the vertical line is thinner than the horizontal length of the dielectric block, and the adhesive injected at the end of the T-shaped vertical line is injected. From the department To inject the serial light-curing adhesive.
Thereby, an appropriate amount of adhesive can be efficiently filled, so that an optical coupler having high reliability and high characteristics can be obtained, and the productivity thereof is improved.

Alternatively, a rod-shaped dielectric block separated from the gap layer on the optical waveguide layer by a patterned photoresist is adhered by a photo-curing adhesive injected into the photoresist pattern, and subsequently, In a method of manufacturing a photodetector for removing a photoresist after dicing an element, the support of a rod-shaped dielectric block is substantially T
A substantially T-shaped photoresist pattern having a horizontal length shorter than a horizontal length of an adhesive surface per one chip of the dielectric block, and a vertical length of the dielectric block being bonded to the dielectric block. Longer than the vertical length of the surface,
In addition, the thickness of the horizontal line forming the substantially T-shape is made smaller than the vertical length of the rod-shaped dielectric block, and the thickness of the vertical line is made smaller than the horizontal length per chip of the rod-shaped dielectric block. When the rod-shaped dielectric block is disposed at both upper ends of the horizontal line, a punch-out portion is provided at a portion protruding without being covered by the rod-shaped dielectric block, and an adhesive injected at an end of the substantially T-shaped vertical line is provided. The photocurable adhesive is injected from the part. As a result, an appropriate amount of adhesive can be efficiently filled, so that an optical coupler having high reliability and high characteristics is obtained, and the productivity thereof is improved.

Further, the T formed on the photoresist
In the vertical line of the letter or the substantially T-shaped pattern, the line width of a portion protruding without being hidden when the dielectric block or the rod-shaped dielectric block is arranged is set below the dielectric block or the rod-shaped dielectric block. By making the line width smaller than the line width of the hidden portion, an appropriate amount of adhesive can be filled more efficiently, and the productivity of the optical coupler is further improved.

Further, if the bonding surface is pressed and fixed by using the upper surface of the dielectric block or the rod-shaped dielectric block, the prism will not be displaced from the position adjustment to the completion of the bonding, so that the optical coupler having high characteristics can be obtained. And the productivity is improved.

If the dielectric block or the rod-shaped dielectric block is pressed and fixed with a probe sufficiently thinner than the above, the influence of the shadow upon light irradiation can be minimized, so that the productivity of the optical coupler can be reduced. And the characteristics are stabilized.

If the upper surface of the dielectric block or the rod-shaped dielectric block is an optically polished surface, the filling of the adhesive can be observed under a microscope through the optically polished surface. For this reason, it is possible to prevent the excess adhesive from overflowing to the side surface of the prism and reaching the component holding the prism, or from remaining bubbles due to the shortage of the adhesive. In addition, the adhesive can be sufficiently irradiated with light. Thereby, the characteristics of the photodetector are stabilized, and the productivity is improved.

In addition, by subjecting the bonding surface of the dielectric block or rod-shaped dielectric block supported only by the cured adhesive layer to plasma treatment in advance, the adhesive force is increased, and these are not peeled off. Therefore, it is possible to stabilize the element characteristics and improve the yield.

Further, by subjecting both the bonding surface of the dielectric block or the rod-shaped dielectric block and the bonding surface of the gap layer surface to plasma treatment in advance, the bonding force is further increased, and the peeling of these bonding surfaces does not occur. For this reason, the element characteristics can be further stabilized and the yield can be further improved.

Furthermore, before the substrate is diced into individual device chips, by removing the photoresist in a portion passing through the blade in advance, the blade may be damaged during dicing or the cutting speed may be reduced. Since it can be prevented, productivity is improved.

By making the above-mentioned dielectric block or rod-shaped dielectric block a trapezoidal prism, the prism can be fixed using the flat portion of the upper bottom, and the incident light can be made to be incident perpendicularly on the slope. Therefore, an optical coupler having high characteristics can be obtained.

Alternatively, if the dielectric block or the rod-shaped dielectric block is a parallelogram prism, an inexpensive optical coupler can be obtained, and the cost can be reduced.

Alternatively, if the dielectric block or the rod-shaped dielectric block is formed as an inverted trapezoidal prism, incident light can be made incident perpendicularly on the substrate, so that an optical coupler suitable for reduction in size and weight can be obtained. be able to.

Further, if the above-mentioned dielectric block or rod-like dielectric block is used as a beam splitter, it is possible to obtain a photodetector with high characteristics and high reliability which is not affected by contamination on the reflection surface.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in a manufacturing process of an optical coupler according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state after a manufacturing step following FIG. 1;

FIG. 3 is a perspective view showing a state after a manufacturing step following FIG. 2;

FIG. 4 is a perspective view showing a state after a manufacturing step following FIG. 3;

FIG. 5 is a perspective view showing a state after a manufacturing step following FIG. 4;

FIG. 6 is a perspective view showing a state after a manufacturing step following FIG. 5;

FIG. 7 is a perspective view showing a state after a manufacturing step following FIG. 6;

FIG. 8 is a sectional view showing an application example of the optical coupler of the present invention.

FIG. 9 is a perspective view showing a state in a manufacturing process of an optical coupler according to another embodiment of the present invention.

FIG. 10 is a perspective view showing a state after a manufacturing step following FIG. 9;

FIG. 11 is a perspective view showing a state in a manufacturing process of an optical coupler according to still another embodiment of the present invention.

FIG. 12 is a perspective view showing a state after a manufacturing step following FIG. 11;

FIG. 13 is a perspective view showing a state after a manufacturing step following FIG. 12;

FIG. 14 is a perspective view showing a state in a manufacturing process of an optical coupler according to still another embodiment of the present invention.

FIG. 15 is a perspective view showing a state after a manufacturing step following FIG. 14;

FIG. 16 is a perspective view showing a state after a manufacturing step following FIG. 15;

FIG. 17 is a perspective view showing a state after a manufacturing step following FIG. 16;

FIG. 18 is a sectional view showing an optical coupler according to still another embodiment of the present invention.

FIG. 19 is a sectional view showing an optical coupler according to still another embodiment of the present invention.

FIG. 20 is a sectional view showing an optical coupler according to still another embodiment of the present invention.

FIG. 21 is a cross-sectional view showing an optical coupler according to the related art.

FIG. 22 is a sectional view showing another optical coupler according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Substrate 12 Optical waveguide layer 13 Gap layer 14 Prism 14 'Rod prism 15 Adhesive 16 Light shielding layer 19, 19' Lattice pattern 20 Photoresist layer 21 T-shaped pattern 22 Element chip 23, 23 'Photoresist pattern 23A, 23A 'Adhesive injection part 23B, 23B' Gas release part 23C Adhesive introduction part 24 Thin tube 25 Probe 26 Second thin tube 27 Parallelogram prism 28 Inverted trapezoid prism 29 Beam splitter 30 Light detection unit A Opening of light shielding layer C Light Coupling part E Linear edge L Incident light K Reflecting surface T Tapered part

Claims (13)

[Claims] A step of providing an optical waveguide layer and a gap layer on a substrate; a step of patterning a photoresist layer provided on the gap layer into a predetermined pattern; Adhering a dielectric block with a photocurable adhesive, dicing the substrate into individual device chips, and removing the photoresist layer from the individual device chips. The predetermined pattern of the photoresist layer is a T-shaped pattern, and the T-shaped lateral length of the T-shaped pattern is the bonding surface of the dielectric block. , The vertical length of the T-shape is longer than the vertical length of the adhesive surface of the dielectric block, and the thickness of the horizontal line forming the T-shape is greater than the dielectric length. The vertical length of the block And the thickness of the vertical line forming the T-shape is smaller than the horizontal length of the dielectric block, and the light curing is performed from the adhesive injection portion provided at the tip of the vertical line of the T-shape. A method for manufacturing an optical coupler, in which a mold adhesive is injected. 2. A step of providing an optical waveguide layer and a gap layer on a substrate; a step of patterning a photoresist layer provided on the gap layer into a predetermined pattern; A step of bonding the rod-shaped dielectric block with a photocurable adhesive; a step of dicing the substrate and the rod-shaped dielectric block simultaneously to separate individual device chips; and a step of forming the photoresist layer from the individual device chips. And removing the photo-coupler. The predetermined pattern of the photoresist layer is a substantially T-shaped pattern, and the substantially T-shaped lateral direction of the substantially T-shaped pattern is provided. Is shorter than the horizontal length of the bonding surface per chip of the rod-shaped dielectric block, and the substantially T-shaped vertical length is the bonding surface of the bonding surface per chip of the rod-shaped dielectric block. The length of the horizontal line that is longer than the length in the vertical direction is smaller than the length of the rod-shaped dielectric block in the vertical direction, and the thickness of the vertical line that is substantially T-shaped is smaller than the length of the rod-shaped dielectric block. One of the body blocks
A gas vent portion is provided at a tip end of the substantially T-shaped horizontal line, and an adhesive injection portion provided at a tip end of the substantially T-shaped vertical line; A method for manufacturing an optical coupler, comprising injecting the photocurable adhesive from a substrate. 3. When the dielectric block or the bar-shaped dielectric block is disposed, the dielectric block or the rod-shaped dielectric block is arranged in the vertical line of the T-shaped pattern or the substantially T-shaped pattern provided on the photoresist layer. 3. The optical coupler according to claim 1, wherein the width of the portion not covered by the rod-shaped dielectric block is smaller than the width of the dielectric block or the portion covered by the rod-shaped dielectric block. Method. 4. The method according to claim 1, wherein when the dielectric block or the rod-shaped dielectric block is bonded, the upper surface of the dielectric block or the rod-shaped dielectric block is pressed and fixed. Method for manufacturing an optical coupler. 5. The pressure fixing using the upper surface of the dielectric block or the rod-shaped dielectric block is performed by a probe sufficiently smaller than the size of the dielectric block or the rod-shaped dielectric block. 3. The method for manufacturing an optical coupler according to claim 1. 6. The optical block according to claim 1, wherein an upper surface of said dielectric block or said rod-shaped dielectric block is an optically polished surface.
The method for manufacturing an optical coupler according to any one of the above. 7. The method according to claim 1, further comprising a step of subjecting the bonding surface of the dielectric block or the rod-shaped dielectric block to a plasma treatment prior to the bonding of the dielectric block or the rod-shaped dielectric block. A method for manufacturing the optical coupler according to any one of the above. 8. The method according to claim 1, further comprising a step of performing a plasma treatment on the bonding surface of the dielectric block or the rod-shaped dielectric block and the bonding surface of the gap layer before bonding the dielectric block or the rod-shaped dielectric block. The method for manufacturing an optical coupler according to claim 1, wherein: 9. Prior to the substrate dicing process,
9. The method according to claim 1, further comprising a step of removing the photoresist layer at a portion corresponding to a portion to be diced on the substrate with a width wider than a width of a blade used at the time of dicing. Method for manufacturing an optical coupler. 10. The method according to claim 1, wherein the dielectric block or the rod-shaped dielectric block is a trapezoidal prism. 11. The method according to claim 1, wherein the dielectric block or the rod-shaped dielectric block is a parallelogram prism. 12. The dielectric block or the rod-shaped dielectric block is an inverted trapezoidal prism.
The method for manufacturing an optical coupler according to any one of the above. 13. The method for manufacturing an optical coupler according to claim 1, wherein said dielectric block or said rod-shaped dielectric block is a beam splitter.