JPH1017331A - Optical waveguide film manufacturing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for producing an optical waveguide film which makes a film thickness uniform without impairing the deposition efficiency of the glass particulates deposited on a substrate and forms less air bubbles and scattering. SOLUTION: This apparatus for production is constituted so as to have a glass particulate synthesizing burner 3 which deposits the glass particulates 5 onto the substrate 2 by blowing the glass particulates 5 together with an oxyhydrogen frame to the substrate 2 from above and a discharge pipe 4 which expels the excess glass particulates failing to adhere on the substrate 2 from the parts near the substrate 2. In such a case, the air velocity of the discharge flow of the discharge pipe 4 is slower in the central part than in the outer peripheral part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide film manufacturing apparatus for depositing glass fine particles on a substrate by using a flame deposition method to form a porous thin film.

[0002]

2. Description of the Related Art A silica-based optical waveguide that can be formed on a substrate made of silicon or the like has been widely used as a waveguide component or an optical integrated circuit because of its low transmission loss and good matching with a silica-based optical fiber. . Various manufacturing methods have been proposed for this quartz optical waveguide. One of the manufacturing methods is a flame deposition method. FIG. 5 is a schematic diagram of a conventional flame deposition method, and FIG. 6 is a schematic diagram of a main part thereof. 5 or 6, reference numeral 1 denotes a turntable. A plurality of heat-resistant substrates 2 such as quartz glass or silicon are provided on the turntable 1. Reference numeral 3 denotes a burner for synthesizing glass fine particles. Glass fine particles 5 are sprayed onto the substrate 2 together with the oxyhydrogen flame from the burner 3 for synthesizing glass fine particles, and porous glass is formed on the substrate 2 by a flame hydrolysis reaction. Layer 5A is deposited. On the other hand, surplus glass particles 5 that could not be deposited on the substrate 2 are exhausted by the exhaust pipe 14.

[0003]

SUMMARY OF THE INVENTION Excess glass particles 5
When the exhaust gas is exhausted from the exhaust pipe 14, the excess amount of the glass particles 5 is quickly discharged by increasing the exhaust amount of the exhaust pipe 14, but on the other hand, the flame of the tip of the burner 3 for synthesizing the glass particles fluctuates. This is problematic in that the thickness of the glass particles 5 deposited on the substrate 2 tends to be uneven and the deposition efficiency is poor. On the other hand, when the amount of exhaust from the exhaust pipe 14 is reduced, the deposition efficiency is improved, but the surplus glass fine particles 5 stay in portions other than the substrate 2 and a part thereof
Since the substrate adhered on the transparent vitrification, the substrate after the vitrification contained bubbles or had irregularities on the surface, causing scattering.

An object of the present invention is to solve the above-mentioned problems and to provide an apparatus for manufacturing an optical waveguide film having a uniform film thickness without impairing the deposition efficiency of glass fine particles deposited on a substrate and having less bubbles and scattering. is there.

[0005]

The present invention has the following means to solve the above problems.

According to a first aspect of the present invention, there is provided an optical waveguide film manufacturing apparatus, comprising: a glass particle synthesizing burner for spraying glass particles together with an oxyhydrogen flame from above the substrate to deposit the glass particles on the substrate; An apparatus for manufacturing an optical waveguide film having an exhaust pipe for removing excess glass particles that have not adhered from the vicinity of the substrate, wherein the wind speed of the exhaust flow of the exhaust pipe is lower at the center than at the outer periphery. It is characterized by the following.

According to the optical waveguide film manufacturing apparatus of the present invention,
Since the wind speed of the exhaust flow of the exhaust pipe that removes the excessive fine particles that have not adhered onto the substrate is lower at the center than at the outer periphery, turbulence around the exhaust pipe is suppressed. As a result, no fluctuation occurs in the flame at the tip of the burner for synthesizing glass fine particles even when the exhaust volume of the exhaust pipe is increased, so that the film thickness of the glass fine particles deposited on the substrate does not become uneven, and the film becomes thin. The thickness can be made uniform. Of course, since the exhaust volume of the exhaust pipe can be made sufficiently large, surplus glass fine particles can be quickly discharged, and the surplus glass fine particles stay in portions other than the substrate, and a part of the particles remains on the substrate. There is no sticking, and there is no generation of bubbles or scattering on the transparent vitrified substrate.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an apparatus for manufacturing an optical waveguide film according to the present invention will be described below in more detail with reference to FIGS. FIG. 1 is a schematic view showing an embodiment of an apparatus for manufacturing an optical waveguide film according to the present invention, and FIGS. 2 to 4 are schematic views of main parts of the apparatus for manufacturing an optical waveguide film according to the present invention. In FIG. 1, 1 is a turntable, 2 is a substrate, 3 is a burner for synthesizing glass particles, and 4 is an exhaust pipe. The turntable 1 is adapted to rotate horizontally in the direction of the arrow. A plurality of substrates 2 made of silicon or the like are placed on the heated turntable 1. Bar for synthesizing glass fine particles by injecting oxyhydrogen flame and glass fine particles 5
The nut 3 is held at a fixed angle with respect to the substrate 2 as shown in FIG. The exhaust pipe 4 is arranged so as to face the burner 3 for synthesizing glass fine particles at a predetermined distance from the substrate 2.

(Embodiment) A case where an optical waveguide film is manufactured by the manufacturing apparatus configured as described above will be described more specifically. The size of the turntable 1 is 1600 mm in diameter
φ, which is heated to 700 ° C.
Is placed on it. A 4-inch silicon substrate was used as the substrate 2 on which the glass microporous film 5A was deposited. The burner 3 for synthesizing glass fine particles is a quadruple tube burner, and the innermost layer of the burner 3 has, as an example, 120 cc / raw material as a raw material.
Of SiCl ₄ , 28 cc / min of BCl, 14 cc / min of PCl ₃ and 180 cc of Ar as a carrier gas. 4.5 l / min of H ₂ in the second layer and A in the third layer
r was supplied at 3 l / min, and O ₂ was supplied to the fourth layer at 7 l / min.

[0010] The burner 3 for synthesizing glass fine particles is turn-shaped.
The bull 1 was reciprocated in the radial direction from the center of the bull 1 in the range of 80 mm to 300 mm at a speed of 250 mm / min. Turntable 1 was rotated at 15 rpm. As described above, the glass fine particles 5 were deposited for 8 minutes while uniformly scanning the burner 3 for synthesizing glass fine particles with the turntable 1. As shown in FIG. 3, the exhaust pipe 4 for removing excess glass particles 5 is provided with a wind speed adjusting mechanism 6 inside the exhaust pipe 4. The wind speed adjusting mechanism 6 includes an inner pipe 4B provided inside the outer pipe 4A of the exhaust pipe 4, and a disk 4C provided on the inner pipe 4B. One at the center of the disk 4C and 6
The plurality of through holes 4D are arranged. This wind speed adjusting mechanism 6
Accordingly, the exhaust pipe 4 has a structure in which the wind speed increases toward the outer peripheral portion of the exhaust pipe, as shown in the wind speed distribution shown in FIG.

When the air was exhausted at an exhaust pressure of 3.5 m / min using the exhaust pipe 4 having the above-mentioned wind speed adjusting mechanism 6, the excess glass particles 5 were quickly removed, and there was no sway of the flame. Did not. The substrate 2 on which the deposition of the glass particles 5 was performed for 8 minutes was vitrified in an O ₂ -He gas atmosphere at 1270 ° C. All of the eight vitrified substrates 2 become transparent vitrified, and the glass thickness of the substrate 2 is 38.3-39.
It was stable in the range of 5 μm.

(Comparative Example 1) As the exhaust pipe, a simple cylindrical one having the same outer diameter and inner diameter as the exhaust pipe 4 of the embodiment was used, and the other conditions were the same as those of the embodiment, and glass fine particles were deposited on the substrate. Performed for 8 minutes. In the case of this comparative example, the exhaust pressure (3.5 m / min) was insufficient and glass fine particles flew besides the substrate. When eight substrates on which glass fine particles were deposited for 8 minutes were vitrified, there were many bright points on the glass surface. The thickness varied from 41.8 to 43.2 μm.

(Comparative Example 2) As the exhaust pipe, a simple cylindrical one having the same outer diameter and inner diameter as the exhaust pipe 4 of the embodiment was used, and the exhaust pressure was set to 4 m / min. Under the conditions, glass particles were deposited on the substrate for 8 minutes.
In the case of this comparative example, the flame fluctuated. When the eight substrates on which the deposition of the glass particles was performed for 8 minutes were vitrified, the film thickness was as thin as 28.8 to 31 μm and the variation was large.

As described above, according to the optical waveguide film manufacturing apparatus of the present invention, the film thickness is made uniform without deteriorating the deposition efficiency of the glass fine particles deposited on the substrate, and the optical waveguide film with less bubbles and scattering is provided. Can be manufactured. In the above-described embodiment, the mechanism shown in FIG. 3 has been described as a wind speed adjusting mechanism of the exhaust pipe. However, the wind speed adjusting mechanism is not limited to the above-described one. For example, as shown in FIG. The end portion is made square, and as a triple tube having a square inner tube 7B inside the outer tube 7A and a square center tube 7C inside the inner tube 7B, a damper 7D is provided on the center tube 7C, Appropriate means such as adjusting the air volume so that the wind speed becomes higher toward the outer periphery of the exhaust pipe as shown in the wind speed distribution shown in FIG.

[0015]

As described above, according to the optical waveguide film manufacturing apparatus of the present invention, the wind speed of the exhaust flow of the exhaust pipe for removing the extra fine particles that have not adhered to the substrate is such that the center portion has an outer peripheral portion. Turbulence around the exhaust pipe is suppressed. As a result, no fluctuation occurs in the flame at the tip of the burner for synthesizing glass fine particles even when the exhaust volume of the exhaust pipe is increased, so that the thickness of the glass fine particles deposited on the substrate does not become uneven. The film thickness can be made uniform.

Of course, since the exhaust volume of the exhaust pipe can be made sufficiently large, surplus glass fine particles can be quickly discharged, and the surplus glass fine particles stay in portions other than the substrate, and a part of them remains. It does not adhere to the substrate and does not cause bubbles or scattering on the transparent vitrified substrate.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an apparatus for manufacturing an optical waveguide film according to the present invention.

FIG. 2 is a schematic view showing a main part of an apparatus for manufacturing the optical waveguide film of FIG. 1;

FIG. 3 is an explanatory view showing an example of an exhaust pipe used in the optical waveguide film manufacturing apparatus of FIG.

FIG. 4 is an explanatory view showing another example of the exhaust pipe used in the optical waveguide film manufacturing apparatus of FIG. 1;

FIG. 5 is a schematic view showing an example of a conventional optical waveguide film manufacturing apparatus.

FIG. 6 is a schematic view showing a main part of the apparatus for manufacturing the optical waveguide film of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turntable 2 Substrate 3 Burner for glass fine particle synthesis 4 Exhaust pipe 5 Glass fine particle 5A Porous film of glass fine particle 6 Wind speed adjusting mechanism

Claims (1)

[Claims] 1. A glass particle synthesis burner for spraying glass particles from above the substrate together with an oxyhydrogen flame to deposit the glass particles on the substrate, and removing excess glass particles not adhering to the substrate from the vicinity of the substrate. An apparatus for manufacturing an optical waveguide film having an exhaust pipe, wherein a wind speed of an exhaust flow of the exhaust pipe is lower at a central portion than at an outer peripheral portion.