JP3434572B2 - Method for producing opaque quartz glass member with transparent quartz glass layer - Google Patents

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 an opaque quartz glass member with a transparent quartz glass layer, and in particular, a quartz glass with a flange portion constituting a bell jar, a diffusion furnace core tube, a boat holding jig for semiconductor production. The present invention relates to a method for manufacturing a flange portion of a container.

[0002]

2. Description of the Related Art Conventionally, quartz glass is high in purity and excellent in heat resistance. Therefore, jigs and tools for semiconductor manufacturing, such as bell jars for semiconductor manufacturing, diffusion furnace core tubes, and flanges for boat holding jigs, etc. It has been used as a material for attached quartz glass containers. In this semiconductor manufacturing tool, radiant heat is generated in the container, which heat-deteriorates the sealing member at the end of the container, so the flange part is generally made of opaque quartz glass containing fine bubbles. It was target. However, the opaque quartz glass contains many air bubbles, which are exposed on the sealing surface, and even if a packing material is used, the flange portion cannot be completely sealed. So, I tried to tighten the flange strongly, but it was easily broken from the place where the material was glass. Also, a method of increasing the gas pressure inside the container to prevent the intrusion of impurities from the sealing surface was considered, but the diffusion process or the epitaxial growth process needs to be performed at a specific pressure so as to prevent uneven diffusion and uneven deposition. It could not be implemented. As a solution to these drawbacks of conventional jigs for semiconductor manufacturing,
A laminated quartz glass member having a transparent quartz glass layer formed on an opaque quartz glass layer has been proposed in Japanese Utility Model Publication No. 1-43164.

However, in the above laminated quartz glass member, since the transparent glass plate is welded to the flange portion, large bubbles remain at the interface between the transparent layer and the opaque layer at the time of welding, or partial cooling causes cracks and breaks. Was often found.

[0004]

Therefore, as a result of intensive studies by the present inventors, an opaque quartz glass member excellent in sealing property, particularly a flange, is obtained by forming a transparent quartz glass on an opaque quartz glass body by the Bernoulli method. The present invention has been completed by finding that the flange portion of the attached container can be manufactured.

That is, it is an object of the present invention to provide a method for producing an opaque quartz glass member with a transparent quartz glass layer in which the sealing surface is flat with a surface roughness of 200 μm or less and no large bubbles are present at the interface. .

Another object of the present invention is to provide a method for manufacturing a flange portion of a flanged container which has a good heat insulating property and an excellent sealing property.

[0007]

SUMMARY OF THE INVENTION The present invention for achieving the above object is achieved by placing an opaque quartz glass body, which has a flat surface with a surface roughness of 200 μm or less and contains bubbles therein, on a turntable and rotates it. A method for producing an opaque quartz glass member with a transparent quartz glass layer, which comprises melting and dropping quartz powder through a burner installed above the smooth surface of the opaque quartz glass body to form a deposited layer of transparent quartz glass. .

As the opaque quartz glass body used in the above manufacturing method, Japanese Patent Application No. 5-2 proposed by the present inventors, which does not contaminate semiconductor products and is excellent in heat shielding and heat resistance.
2963 opaque quartz glass of No. 8 wherein, i.e. a specific gravity of 2.08 to 2.18, the bubble diameter 10～160Myuemu bubbles total area 800～1,500Cm ^2, total bubble volume of 3
An opaque quartz glass body having an alkali metal element concentration of 0.2 ppm or less and an OH group concentration of 10 ppm or less in the substrate is suitable for 10 to 10%. By using this opaque quartz glass body, it is possible to manufacture a bell jar for semiconductor production, a diffusion furnace core tube, a boat holding jig, etc., which have excellent heat shielding properties and heat resistance.

As the quartz powder which is the raw material of the transparent quartz glass, the concentration of alkali metal element is 1 ppm or less and the concentration of alkaline earth group element is 0.5 ppm or less, which is obtained by purifying natural crystalline quartz powder. Quartz powder having a heavy metal element concentration of 1 ppm or less and having a particle size adjusted to 350 to 70 μm is suitable. When the particle size is less than the above range, the transparent quartz glass layer is difficult to be formed, and when it exceeds the above range, bubbles are mixed.

The manufacturing method of the present invention will be described with reference to FIG. In FIG. 1, 1 is an opaque quartz glass plate, 2 is a transparent quartz glass layer deposited on an opaque quartz glass body, 3 is a turntable for rotating the opaque quartz glass body 1, and 4 is located above the turntable. Burners 5 are quartz powders supplied to the burners. According to the manufacturing method of the present invention, the opaque quartz glass body 1 is placed on the rotary table 3 and rotated, and the quartz powder 5 is supplied into the flame 6 of the burner 4 installed above the rotary table 3.
This is a manufacturing method in which the fused and dropped quartz glass is deposited to form a transparent quartz glass layer 2, then the transparent quartz glass layer is flat-polished, and further, if necessary, baked and finished to have a surface roughness of 2 μm or less. .

In the above manufacturing method, when a doughnut-shaped opaque quartz glass plate is used as the opaque quartz glass body 1, the edges of the inner diameter portion and the outer diameter portion are strongly scraped by the flow of flame,
Alternatively, since it sublimates and becomes unsuitable in shape, a quartz glass block having the same height as the height of the opaque quartz glass body is placed in the vicinity of the inner peripheral portion and the outer peripheral portion as shown in FIG. It is better not to lick the edges.

In the manufacturing method of the present invention, the heating temperature of the burner is preferably 2,000 ° C. or higher. Further it is to change arbitrarily the position for forming the transparent quartz glass layer position of the burner. The transparency of the obtained transparent quartz glass layer is DIN
It was 3 or more in the 58927 standard.

The transparent quartz glass melted and dropped in the above manufacturing method is filled in the exposed bubbles to form a non-bubble portion. The bubbles near the surface of the opaque quartz glass plate expand the gas contained therein by heating the burner, and expand by a factor of 2 to 3. Therefore, if the deposited transparent quartz glass layer is thin, the bubbles are exposed during the flattening to form irregularities on the surface. Therefore, the thickness of the deposited layer should be 5 times or more, preferably 10 times or more the bubble diameter.

[0014]

EXAMPLES The present invention will be described below with reference to examples. Example 1 It has a flat surface with a surface roughness of about 100 μm by means of flat grinding, a specific gravity of 2.08 to 2.18, and a bubble diameter of 10 to 160 μm.
m, total bubble volume 3 to 10%, bubble area 800 to 1500
cm ^2, sodium element concentration 0.2ppm or less, elemental potassium concentration 0.2ppm or less, the outer diameter of the following opaque quartz glass OH group concentration 10ppm 330mmφ × thickness 30m
m plate material, put it on a table that rotates at 8 rpm, and while rotating it, the natural quartz crystal powder with grain size and elemental concentration shown in Table 1 is placed at a center point above the outer peripheral portion of the plate material at a point 40 mm inside. In the flame of a burner that has defined (gas conditions;
H ₂ : 400 l / min, O ₂ ; 200 l / min) 4
It was melted and dropped while passing it at a speed of g / min. This melting and dropping was continuously performed for 3 hours to form a transparent quartz glass layer on the flat surface of the opaque quartz glass plate. The thickness distribution of the transparent quartz glass layer 2 was 5 mm at maximum. The width of the portion having a thickness of 2 mm or more was, as shown in FIG. 2, from a portion 5 mm inside to the outer peripheral portion to a portion 80 mm inside. The opaque quartz glass plate material with the transparent quartz glass layer produced in this manner is used to have an outer diameter of 320 mmφ and an inner diameter of 180 mm.
It was processed into φ and further surface-ground. By the surface grinding, the deposited transparent quartz glass was formed into a uniform layer having a thickness of about 1.5 mm.
Next, the transparent quartz glass layer was baked and finished. As a result, the surface roughness of the transparent quartz glass layer was within ± 2 μm.

[0015]

[Table 1]

Example 2 As an opaque quartz glass plate, the dimensions are 320 mmφ outer diameter × 180 mmφ inner diameter × 30 mm thickness.
The doughnut-shaped opaque quartz glass plate was used, and the quartz block 7 was set on the edges of the outer peripheral portion and the hollow portion. Then, an opaque quartz glass member with a transparent quartz glass layer was prepared by the same manufacturing method as in Example 1. When this member was finished in the same manner as in Example 1, the surface roughness was still within 2 μm .

COMPARATIVE EXAMPLE 1 An opaque quartz glass plate material similar to that of Example 1 was used with an outer diameter of 320 m.
It was processed into a donut shape of mφ × 180 mmφ inner diameter, and the surface was flat-ground. A transparent quartz glass plate was welded to this flat-polished surface by an oxyhydrogen flame burner. At the interface between the transparent quartz glass layer and the surface of the opaque quartz glass, bubbles of about 2 mm to 7 mm occurred frequently. When the laminated quartz glass member consisting of the fused transparent quartz glass layer and the opaque quartz glass layer was subjected to surface grinding, the hollows of the bubbles were exposed and a gas leak occurred when it was used as a flange portion. Also, cracks were found at the part where welding was completed, and some of them became unusable.

Comparative Example 2 An opaque quartz glass member subjected to flat grinding was molded into a donut shape,
A transparent quartz glass layer was formed on the surface in the same manner as in Example 2 except that the quartz glass block was not set in the outer peripheral portion and the hollow portion. The inner peripheral edge and the outer peripheral edge of the obtained opaque quartz glass member were scraped by about 15 mm in width and about 5 mm in depth due to the influence of the flame from the burner, and there were many parts that could not be used as a member.

A maximum of 0.5 mm was formed on the opaque quartz glass plate having the same physical properties as in Example 1 by the same method as in Example 1.
A transparent quartz glass layer having a thickness of 1 was formed. When this member was flat-polished and the surface roughness thereof was measured, a maximum roughness of 500 m was measured as shown in Fig. 6 .

[0020]

According to the manufacturing method of the present invention, it is possible to manufacture an opaque quartz glass member having a flat surface having a surface roughness of 2 μm or less and having an excellent sealing property. With a flange for semiconductor manufacturing that has excellent heat resistance and high-purity sealability.

[Brief description of drawings]

FIG. 1 is a schematic view of a manufacturing method showing one embodiment of the present invention.

FIG. 2 is a schematic view of an opaque quartz glass member having a transparent quartz glass layer obtained by the manufacturing method of FIG.

FIG. 3 is a schematic view of a manufacturing method showing another embodiment of the present invention.

FIG. 4 is a graph showing the surface roughness of the opaque quartz glass of the present invention.

FIG. 5 is a graph showing the surface roughness of the transparent quartz glass layer obtained by the manufacturing method of the present invention.

FIG. 6 is a graph showing the surface roughness when a thin transparent quartz glass layer is formed on an opaque quartz glass layer.

[Explanation of symbols]

1 Opaque quartz glass plate 2 Transparent quartz glass layer 3 turntable 4 burners 5 Quartz powder 6 flames 7 blocks

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toru Yokota, Toru Yokota, Kawamura, Kanaya, Tamura-cho, Koriyama City, Fukushima 88, Shin-Etsu Quartz Co., Ltd. Step 1357-3 Yamagata Shin-Etsu Quartz Co., Ltd. (56) Reference JP-A-1-148718 (JP, A) JP-A-6-92779 (JP, A) JP-A-1-148783 (JP, A) JP Sho 63-236723 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C03B 20/00 C03B 19/00 C03C 17/00-17/44 C03C 23/00 C03C 27/00- 27/12

Claims (4)

(57) [Claims] 1. A flat surface having a surface roughness of 200 μm or less,
An opaque quartz glass body containing air bubbles inside is placed on a turntable and rotated, and quartz powder is melted and dropped through a burner installed above the flat surface of the opaque quartz glass body, and a deposited layer of transparent quartz glass A method for producing an opaque quartz glass member with a transparent quartz glass layer, the method comprising: 2. A flat surface having a surface roughness of 200 μm or less,
A doughnut-shaped opaque quartz glass body containing bubbles inside is placed on a turntable, and a block having the same height as the opaque quartz glass body is placed near the inner and / or outer circumference of the turntable and the turntable is rotated. Meanwhile, the quartz powder supplied to the burner installed above the opaque quartz glass body is melted and dropped onto the doughnut-shaped opaque quartz glass plate to form a deposited layer of transparent quartz glass. Of manufacturing an opaque quartz glass member with a coating. 3. The opaque quartz glass body has a specific gravity of 2.08 to
2.18, the bubble diameter is 10 to 160 μm, the total bubble volume is 3 to 10%, the alkali metal element concentration in the substrate is 0.2 ppm or less, and the OH group concentration is 10 ppm or less. The method for producing an opaque quartz glass member with a transparent quartz glass layer according to claim 1 or 2. 4. The thickness of the transparent quartz glass layer formed on the opaque quartz glass body is not less than 5 times the maximum diameter of the bubbles contained in the opaque quartz glass body. 4. The method for producing an opaque quartz glass member with a transparent quartz glass layer according to any one of 3 above.