JPS6054932A - Mass-production of quartz glass plate - Google Patents

Abstract

PURPOSE:To enable the mass-production of quartz glass plate having high flatness, by manufacutring a thick dry gel by the sol-gel process from a metal alkoxide, sintering the dry gel, and slicing the obtained thick quartz glass. CONSTITUTION:Ethyl silicate is hydrolyzed with an aqueous solution of hydrochloric acid, mixed with fine silica powder, dispersed uniformly, and adjusted to 4-6pH. The obtained sol is poured into a deep vessel having flat bottom to a sufficient depth, and gelatinized and dried under free shrinkage to obtain a thick dry gel. The thick dry gel is sintered to obtain a thick quartz glass plate, which is sliced to a plurality of flat quartz glass plates having the required thickness to obtain a plurality of flat quartz glass plates at the same time. Since the dry gel prepared by this process has large thickness, it is resistant to warpage in drying, and gives the thick quartz glass plate having high flatness by drying. Accordingly, the process has high yield and is suitable for mass-production, and the flatness of the plate can be improved further by slicing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing quartz glass by a sol-gel method using at least a metal alkoxide as a raw material, and more particularly to a method for mass-producing flat quartz glass with good flatness.

Quartz glass began to be used in crucibles, boards, diffusion furnaces, etc. during the IC manufacturing process, and its usefulness was recognized.
Products with fewer hydroxyl groups in F and those with optical uniformity have been developed and are used in various optical applications. Quartz glass fiber - Don't pay attention to quartz glass masks for home use, TO use (Haru.Ni 1 Thin Film Transistor (TPT)
It is also attracting attention as a substrate for quartz glass masks and T
Applications of flat quartz glass, such as PT law plates, are also expanding.

Flat fused silica glass is generally manufactured in two ways. One method is to create a rod by melting natural quartz [7] or by melting synthetic quartz [11], and this method involves cutting the rod into rounds. Also, instead of having a do-shaped shape, a hollow cylindrical tube is created7, which is then cut open to make it into a planar shape.

In either method, the production temperature is high (and the raw materials are expensive, so the flat quartz glass that is commercially available is expensive. Attempts have been made to produce quartz glass at a lower cost using the gel method.In general, methods for producing quartz glass using the sol-gel method can be divided into the following three types.

A metal alkoxide is hydrolyzed under an alkaline acidic acid catalyst, gelled as a sol, dried to form a dry gel, and sintered to form quartz glass. One offal,
Metal alkoxide is not used as a raw material, but fine powder silica is used as a raw material.

This is done by adding fine powder silica to water, making it hydrosil, leaving it to gel, making it a dry gel, and sintering the dry gel.1. It is made of quartz glass.

Moreover, it is made from metal alkoxide and finely powdered silica. This involves adding finely powdered silica to a sol solution obtained by hydrolyzing a metal alkoxide, and then adjusting the pH.
The mixture is adjusted to near neutrality, left to gel, dried to form a dry gel, and then sintered to form quartz glass. Of these methods, the most gentle method for producing bulk quartz glass is the method mentioned last, which uses metal alkoxide and finely powdered silica as raw materials. Therefore, although the cost and γY embodiments of the present invention will be written based on this method, it is clear that the two middle methods have similar effects.

As mentioned above, flat quartz glass generally has many uses, but it has the drawback of being expensive.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a stone mass production method for manufacturing flat quartz glass at low cost.

As a method for doing so, we devised the following method17. That is, ethyl silicate is hydrolyzed by adding hydrochloric acid water, and Aerosi
l (Deggwssa) and aa ho-sir
Add finely powdered silica, which is a white carbon such as 0aly-o-wo Co., Ltd., and disperse it well and uniformly.
Adjust to Party B.

The sol obtained in this way is placed in a deep container with a flat bottom to form a thick gel, and is then shrunk and dried to obtain a thick plate-like dry gel.

This thick dry gel is sintered to form a thick plate of quartz glass.
A plurality of flat quartz glass plates can be obtained from one block of quartz glass by slicing it into flat quartz glass of the required size. Therefore, it is a very effective means for manufacturing flat quartz glass plates in mass production.

Further, when a single quartz plate of the required thickness is produced from a single sheet of oblique quartz glass without slicing, the thickness of the target quartz plate is often thin, so the thickness of the dry gel is also thin. Thin dry gel (d) is often warped due to unevenness during drying or for various reasons, so if tt dry gel that has been warped is sintered, it becomes warped quartz glass, which is difficult to make into a flat plate-shaped quartz glass. Since the dry gel obtained by the method of the present invention is thick, it does not warp very much during drying.In addition, the thick quartz glass obtained by sintering is flat without warping. When manufacturing, it is better to create a thicker dry gel for better yields, and slicing it further improves flatness, making it suitable for mass production.

The present invention will be described in detail below with reference to Examples.

Example 1 540 mt of a 0.02N hydrochloric acid aqueous solution was added to purified commercially available ethyl silicate 624Q (3 mol), and the mixture was vigorously stirred for hydrolysis. Add water to this solution at 30 O? ? ? ! In addition, fine powder silica (Aernsil 0X50:
225 g of Aerosil Co., Ltd.'s surface area 50 m2// (trade name of fine powder silica No. 7) was added under stirring, and operations such as ultrasonic vibration to improve dispersion were performed to obtain a sol with good uniformity.

this.

The sol was filtered to remove dust etc. 01N ammonia water was added dropwise to this sol to adjust the PM to 50H.

This sol was placed in a flat, deep box-shaped container made of polypropylene (3oαx 2 affix 2 acm ).
I filled it to a depth of 6cm, sealed it, and left it at room temperature, and it gelled after 30 minutes, 1! I left it for a day and night.

Replace the lid with one that has holes in it so that the solvent can distill out.5
A stable thick dry gel that does not crack even if left at room temperature after 70 days (21cInx
14cy+X 4cm) was obtained. This thick dry gel was heated slowly to 1200℃ in a sintering furnace.
After being left at 200° C. for 1.5 hours and sintered, a transparent plate-like quartz glass (15 cm x 10 crn x 2.4 cm) was obtained.

This thick plate-shaped quartz glass was sliced into 15crn×1
Eight sheets of plate-shaped quartz glass containing 0 cells and 0.1 bacteria were obtained. 6
- Cutting allowance of the peripheral blade for slicing dashi stock 0.2 crn
Therefore, only the amount of the cut l and ro was wiped out.

It is clear that the method of the present invention is not limited to the sol-gel method using metal alkoxide and finely powdered silica as raw materials as in this example.

Since the flat quartz glass of the present invention can be produced at a lower cost than the conventional method, it is expected to greatly contribute to various fields such as TPT substrates and zero-process masks.

that's all Applicant: Suwa Seikosha Co., Ltd. Agent Patent Attorney Mogami 7- 177-

Claims (1)

[Claims] In a method of synthesizing plate-shaped quartz glass at low temperatures by a sol-gel method using at least a metal alkoxide as a raw material, a plate-shaped dry gel of 18 mm in thickness is prepared, this is sintered to form thick quartz glass, and sliced. 9. A method for mass production of plate-shaped quartz glass, characterized by manufacturing a large number of plates of quartz glass.