JPH05301721A - Production of optical waveguide film - Google Patents

Abstract

PURPOSE:To provide a process for producing a uniform optical waveguide film having improved homogeneity. CONSTITUTION:Oxide glass soot is synthesized at the tip of a burner 54 supplied with a fuel gas, a raw material gas, etc., and the burner 54 is reciprocated relative to a supporting table 52 to deposit the formed soot on the surface of a substrate 56. The scanning motion of the burner 54 at the central area of the moving range is carried out at uniform scanning density and scanning speed to uniformize the staying time of the burner 54 in the area. In the peripheral area of the moving range, the scanning density, etc., are adjusted in such a manner as to increase the staying time of the burner 54 in the peripheral region compared with the time in the central area. An optical waveguide film having uniform thickness almost over the whole surface of a substrate 53 placed in the central area of the moving range can be produced by this process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a low-loss optical waveguide film by a flame deposition method with good controllability of refractive index and film thickness.

[0002]

2. Description of the Related Art In recent years, waveguide-type devices, which are excellent in downsizing and weight saving, are being used as optical parts such as optical branching / imaging elements and optical demultiplexing / multiplexing elements. Among them, the silica-based optical waveguide has many advantages such as low loss, the same refractive index as the silica-based optical fiber, and small connection loss. As a typical method for producing a quartz optical waveguide, there is a flame deposition method disclosed in Japanese Patent Publication No. 63-66512.

FIG. 1 is a diagram showing this flame deposition method. As shown in the figure, glass particles from a burner for synthesizing glass particles (hereinafter simply referred to as burner) 12 are deposited on a heat resistant substrate 10 such as quartz glass or silicon, and porous glass is formed on this heat resistant substrate 10. Forming a quality glass layer. At this time, the burner 12 is supplied with a fuel gas such as H ₂ gas and a combustion supporting gas such as O ₂ gas. Furthermore, SiCl ₄ as a glass raw material, GeCl ₄ , TiCl ₄ as a refractive index adjusting material, and B and P which have the effect of lowering the temperature required for transparentizing the glass by heating later are reduced. BCl _3, BBr ₃ is a Kishoso raw materials,
PCl ₃ , POCl _3, etc. are also supplied. In the vicinity of the outlet of the burner 12, a fine glass particle stream 16 is formed by the perhydrolysis reaction in the flame 14 formed by the reaction of the fuel gas and the combustion supporting gas. At this time, the heat resistant substrate 10
In order to form a porous glass uniformly on the burner 12,
And the heat resistant substrate 10 are relatively moved. For this purpose, for example, a method is used in which the heat resistant substrate 10 is placed on the turntable 16 and revolved, and the burner 12 is reciprocated in the radial direction of the turntable 16. Further, in order to quickly discharge the surplus glass fine particles not deposited on the substrate 10, the burner 12 is arranged so as to be incident at an angle inclined with respect to the normal direction of the substrate 10, and the glass fine particle flow thereof. Exhaust pipe 2 downstream of 18
0 is provided.

[0004]

However, in such a conventional device, there is a problem that the uniformity of the film thickness within the surface of the substrate 10 is poor and the reproducibility of the transmission characteristics of the resulting optical waveguide is poor. It was Further, in the conventional method, the above problem becomes more remarkable as the size of the substrate increases.

Therefore, an object of the present invention is to provide a method capable of producing a uniform optical waveguide film by controlling the supply of glass particles.

[0006]

In order to solve the above problems, in the method for producing an optical waveguide film according to the present invention, glass fine particles synthesized by a burner are deposited on the surface of a substrate to form a porous glass layer. Then, the substrate is heated at a high temperature to make the porous glass layer transparent. Furthermore, in this manufacturing method, when the burner is moved relative to the substrate, the staying time in the peripheral portion of this relative movement range is made relatively longer than in the central portion. In this way, as a method to lengthen the stay time relatively in the peripheral part,
For example, there is a method in which the burner is repeatedly repeatedly moved in parallel in directions opposite to the substrate in a portion other than the peripheral portion of the moving range.

[0007]

In the conventional method, since the center of the moving range has the shortest time average of the distance from the burner, the film thickness at the center inevitably becomes the thickest. For example, when the burner is moved relative to the substrate, the stay time in the peripheral portion of this relative movement range is lengthened, so that almost all of the area on the substrate within this movement range is covered. An optical waveguide film having a more uniform thickness can be formed. Moreover, since the glass particles are hardly supplied to the outside of the above-mentioned movement range, it is possible to reduce the wasteful consumption of the raw material of the glass particles.

[0008]

EXAMPLES Examples of the present invention will be specifically described below.

FIG. 2 shows the structure of an apparatus for carrying out the method for manufacturing an optical waveguide film according to the embodiment.

A support 52 and a burner 54 are housed in the reaction vessel 50. A substrate 56 on which an optical waveguide film is to be formed is fixed on the support base 52. On the substrate 56, the flame from the burner 54 and the glass particles synthesized from the raw material by this flame are sprayed. Board 5
Exhaust substances composed of excess glass particles not deposited on the reaction chamber 6 are quickly exhausted to the outside of the reaction container 50 through the exhaust port 58. In order to uniformly supply and deposit the glass particles on the substrate 56, the support base 52 reciprocates in the X-axis direction (left-right direction in the drawing), and the burner 54 reciprocates in the Y-axis direction (up-down direction in the drawing). Moving. As a result, the burner 54 can freely scan the substrate 56 two-dimensionally.

A manufacturing method using the manufacturing apparatus shown in FIG. 2 will be briefly described. By supplying fuel gas, raw material gas, etc. to the burner 54, the fine particles of the oxide glass synthesized at the tip of the burner 54 are attached and deposited on the surface of the substrate 56. At the same time, the support base 52 and the burner 54 are relatively moved back and forth. In this case, regarding the scanning of the burner 54 in the central region of the reciprocating range, the scanning density and the scanning speed are kept uniform so that the staying time of the burner 54 becomes uniform. Also, regarding the scanning of the burner 54 in the peripheral area of the above-mentioned reciprocating range, the burner 5
The scanning density and the scanning speed are set so that the residence time of 4 is longer than that of the central region. As a result, it is possible to form an optical waveguide film having a uniform thickness over substantially the entire area of the substrate 53 in the central region within the range of this reciprocal movement. In this case, almost no glass fine particles are supplied outside the range of reciprocal movement, so that wasteful consumption of the raw material of glass fine particles can be reduced.

FIG. 3 is a view showing an example of a relative scanning locus of the burner 54 with respect to the support base 52. 3A shows the outline of the first trajectory, FIG. 3B shows the outline of the second trajectory, and FIG. 3C shows the outline of the third trajectory.

In the first locus, the relative movement speeds in the X-axis direction and the Y-axis direction are constant, and uniform scanning is performed within the range of reciprocal movement. Further, at the end of one cycle, rectangular scanning of one rotation or more is performed along the circumference of the illustrated reciprocating range. In addition, the size of the mesh of the trajectory, etc.,
It is different depending on the relative moving speed in each axial direction. In the second locus, parallel scanning is alternately repeated in opposite directions in the central region of the reciprocating range. That is, the relative movement in the X-axis direction periodically stops at the end of the range of the reciprocating movement, and the relative movement in the Y-axis direction is performed only during that period. As a result, the relative movements in the X-axis direction and the Y-axis direction are periodically repeated, and the locus shown in the drawing can be obtained. In this case, the relative movement in the X-axis direction is repeated several times at the end in the Y-axis direction in the range of the reciprocating movement. The third locus is
It is a simple repetition of parallel scanning in the X-axis direction. As a result, it is possible to obtain a locus of parallel scanning as illustrated.

The present invention is not limited to the above embodiment. For example, only one of the burner 54 and the support base 52 can be moved. However, burner 5
A method in which each of the 4 and the support base 52 moves uniaxially is preferable from the viewpoint of downsizing of the apparatus. In this case, X,
The method of taking both the Y-axis is arbitrary. The ratio V _X / V _Y of the relative speed in the X-axis direction and the relative speed in the Y-axis direction is 1 to 200.
The degree is appropriate. Further, the burner 54 and the support base 52
Can also be moved in rotational coordinates. Further, a plurality of substrates can be arranged on the support base 52, and the angle of the burner 54 with respect to the substrate 56 is arbitrary. However, it is desirable to set this angle to about 30 ° to 80 ° from the viewpoint of deposition efficiency.

Hereinafter, the first test performed using the manufacturing apparatus of FIG.
A specific manufacturing example of will be described. A 5-inch Si wafer was used as a substrate on which a porous layer of glass particles was formed. The substrate was set on the support so that its surface coincided with the surface of the support. The burner was arranged at 58 ° with respect to the normal to the surface of the support.
Raw materials are supplied to the burner together with the fuel gas and the combustion supporting gas. The supply of raw material is 100 cc / mi of SiCl _4.
n, BCl ₃ is 30 cc / min, POCl ₃ is 10 c
c / min, Ar as a carrier is 200 cc / mi
It was n (total). The burner was scanned relative to each coordinate axis X, Y on the support in the range of 30-270 mm. The locus of this relative scanning was as shown in FIG. The relative speed of the burner is 40m in the X-axis direction.
m / s and 60 mm / s in the Y-axis direction.

After depositing the porous glass layer under the above conditions, this was heated in another furnace to be transparent and vitrified to obtain a quartz thin film. This thin film became fairly flat in the X-axis direction. Specifically, if the uniform range of the thin film thickness is within ± 1%, the corresponding range is 140 mm.
It was about 35 mm.

For reference, a model calculation was also performed in which the relative speed, the moving range and other conditions of the burner of the first specific manufacturing example were matched. FIG. 4 is a diagram showing the result. The pair of horizontal axes corresponds to both coordinate axes X and Y on the support, and the vertical axis corresponds to the calculated value of the thickness of the porous thin film to be formed. In this case, the calculation range was 300 mm × 300 mm. The uniform range of the thickness of the porous thin film was 150 mm × 40 mm, which was almost the same as in the specific production example. The difference from the specific manufacturing example is considered to be due to the precision of the model.

The second specific manufacturing example will be described below. The conditions such as supply of the raw material to the burner were the same as those in the first specific manufacturing example. The burner scanning range was also the same as in the first specific manufacturing example. For the relative scanning trajectory of the burner,
It is configured as shown in FIG. In this case, the relative speed of the burner is 20 mm / s in the X-axis direction and 8 mm in the Y-axis direction.
It was set to 0 mm / s. Further, the time until the burner returns to the origin again is set as one cycle, and the burner is reciprocated four times at both ends in the Y-axis direction every three cycles.

After depositing the porous glass layer under the above conditions, it was made transparent and vitrified to obtain a quartz thin film. This thin film was flat in both the X-axis direction and the Y-axis direction. Specifically, the uniform range of thin film thickness is 140 m
It was about m × 140 mm.

For reference, a model calculation was also performed in which the relative speed of the burner of the second specific manufacturing example and other conditions were matched. FIG. 5 is a diagram showing the result. As shown in the drawing, the uniform range of the thickness of the thin film was 150 mm × 150 mm, which was almost the same as in the specific production example.

The third specific manufacturing example will be described below. The conditions such as supply of the raw material to the burner were the same as those in the first specific manufacturing example. The burner scanning range was also the same as in the first specific manufacturing example. For the relative scanning trajectory of the burner,
Similar to FIG. 3A, rectangular drive is performed. In this case, the relative speed of the burner was 43 mm / s in the X-axis direction and 14 mm / s in the Y-axis direction. Further, rectangular scanning was performed once per cycle. The relative speed of the burner during rectangular scanning was 40 mm / s in the X-axis direction and 40 mm / s in the Y-axis direction.

After depositing the porous glass layer under the above conditions, it was made transparent and vitrified to obtain a quartz thin film. This thin film was flat in both the X-axis direction and the Y-axis direction. Specifically, the uniform thickness range of the thin film is 120 m.
It was about m × 110 mm.

For reference, a model calculation was also performed in which the relative speed of the burner of the third specific manufacturing example and other conditions were matched. FIG. 6 is a diagram showing the result. As shown in the figure, the uniform range of the thickness of the thin film was 130 mm × 120 mm, which was almost the same as in the specific production example.

A comparative production example will be described below. The conditions such as supply of the raw material to the burner were the same as those in the first specific manufacturing example. The burner scanning range was also the same as in the first specific manufacturing example. The trajectory of the relative scanning of the burner is as shown in FIG. In this case, the relative speed of the burner was 43 mm / s in the X-axis direction and 7 mm / s in the Y-axis direction. Relative movement was performed simultaneously in both axial directions.

After depositing the porous glass layer under the above conditions, it was made transparent and vitrified to obtain a quartz thin film. This thin film became a bell shape that was raised in the center. Specifically, the uniform range of thin film thickness is 18 mm ×
It was about 15 mm.

For reference, a model calculation was also performed in which the relative speed of the burner of the comparative production example and other conditions were matched.
FIG. 8 is a diagram showing the result. As shown in the figure, the uniform range of the thickness of the thin film is almost the same as in the specific manufacturing example.
It was mm × 20 mm.

[0027]

As described above, according to the method of manufacturing an optical waveguide film of the present invention, when the burner is moved relative to the substrate, the burner is moved relative to the substrate. Since the residence time in the peripheral portion of the relative movement range is made relatively longer than that in the central portion, the light guide having a more uniform thickness over almost the entire area on the substrate within this movement range. A corrugated film can be formed. Moreover, since the glass particles are hardly supplied to the outside of the above-mentioned movement range, it is possible to reduce the wasteful consumption of the raw material of the glass particles.

[Brief description of drawings]

FIG. 1 is a diagram showing a conventional manufacturing method.

FIG. 2 is a diagram showing an apparatus for carrying out the manufacturing method of the embodiment.

FIG. 3 is a diagram showing a trajectory of relative movement of a burner with respect to a support base.

FIG. 4 is a diagram showing a model calculation example of a film thickness distribution obtained from the locus of FIG.

5 is a diagram showing another model calculation example of the film thickness distribution obtained from the locus of FIG.

6 is a diagram showing another model calculation example of the film thickness distribution obtained from the locus of FIG.

FIG. 7 is a diagram showing a locus of relative movement in a comparative example.

8 is a diagram showing a model calculation example of a film thickness distribution obtained from the locus of FIG.

[Explanation of symbols]

 54 ... Burner, 56 ... Substrate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Hirose 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Shinji Ishikawa 1 Taya-cho, Sakae-ku, Yokohama, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Masahide Saito 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries Co., Ltd. Yokohama Works

Claims (3)

[Claims] 1. An optical waveguide film for depositing glass fine particles synthesized by a burner on a surface of a substrate to form a porous glass layer, and heating the substrate at a high temperature to make the porous glass layer transparent. In the method, when the burner is moved relative to the substrate, the optical waveguide film is characterized in that the residence time in the peripheral portion of this relative movement range is made relatively longer than in the central portion. Of manufacturing. 2. The method for producing an optical waveguide film according to claim 1, wherein the burner repeats parallel movement alternately in opposite directions with respect to the substrate in a portion other than a peripheral portion of the movement range. .. 3. The burner repeats the movement in which the stay time is substantially uniform in the entire movement range, and also makes a circular movement along the peripheral portion in the peripheral portion of the movement range. 1. The method for producing an optical waveguide film described in 1.