JPS63297226A - Production of short-wavelength laser beam transmitting quartz glass - Google Patents

Abstract

PURPOSE:To obtain a high-quality glass extremely reduced in impurity and foreign matter, by subjecting sol mixed with a product obtained by hydrolyzing an alkyl silicate to gelation with a basic and acid catalyst and drying and sintering the gel product. CONSTITUTION:Fine silica particle produced by hydrolyzing an alkyl silicate under a basic catalyst is dispersed to prepared the first liquid. Alkyl silicate is hydrolyzed under an acid catalyst to prepare the second liquid. Sol prepared by mixing the second liquid with the above-mentioned first liquid at a prescribed rate is subjected to gelation to prepare wet gel, which is then dried to prepare dry gel. The dry gel is successively sintered to prepare the aimed transparent glass product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing glass by a sol-gel method.

[Conventional technology]

The conventional manufacturing method of quartz glass is melting method or CV
It was method D.

[Problem that the invention seeks to solve]

However, in the conventional manufacturing method, there is a point in the molding process in which laser light with a short wavelength of less than 0.2 μm cannot be transmitted.

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problems, and its purpose is to provide a method for producing homogeneous, high-quality quartz glass using a sol-gel method.

[Means for solving problems]

The method for producing short-wavelength laser light-transmissive quartz glass of the present invention is characterized in that in the production of glass by a sol-gel method using an alkyl silicate as a main raw material, silica fine particles, which are a product of a hydrolysis reaction of an alkyl silicate under a basic catalyst, are produced. A step of preparing a wet gel by gelling a sol prepared by mixing a dispersed solution (first solution) and a hydrolysis reaction solution of alkyl silicate using an acidic catalyst (fi2 solution) at a predetermined ratio, the wet gel and a step of sintering the dry gel to produce a transparent glass body.

[Effect]

According to the present invention, since a highly pure liquid raw material can be selected as a raw material, essentially homogeneous, high-quality glass can be produced as long as there is no contamination with impurities such as metal ions or foreign substances such as dust.

〔Example〕

Although there are many examples under various conditions, a typical example will be given here.

■ Preparation of the first liquid Distilled purified ethyl silicate, distilled purified ethanol, distilled purified water, and the highest grade 29% ammonia water for commercial electronics industry, filtered through a membrane filter with a pore size of 0.2 μm, were combined in Table 1. The mixture was mixed with the composition shown in , stirred vigorously for 4 hours, and then allowed to stand overnight in a cool, dark place to grow silica fine particles. After concentrating this silica fine particle dispersion, the pH value was adjusted for stabilization, and the pore size was adjusted to 10 μm.
A first solution was prepared by filtration using a Membrane filter.

Table 1 Note that the average particle diameters of the silica fine particles in the obtained first solutions A, B, and C were measured using a light transmission type centrifugal sedimentation particle size distribution measuring device, and were 0.15 μm, 0.25 μm, and 0.1 μm, respectively.
・Preparation of 2nd liquid Distilled purified ethyl silica) 18. eρ and pore diameter 0,2
The mixture was mixed with 6.15 J2 of 0.02 N hydrochloric acid filtered through a μm membrane filter, and stirred vigorously to carry out a hydrolysis reaction to obtain a second liquid. A total of 3 patches of the second solution were prepared in the same manner.

■ Sol Preparation Mix one batch of the first solution A and the second solution, and then adjust the pore size to 0.
It was filtered through an 8 μm membrane filter and prepared as Sol A.

Similarly, one batch of the first liquid B and the second liquid were mixed and then filtered through a membrane filter with a pore size of 20 μm to prepare sol B.

Similarly, one batch of the first liquid C and the second liquid were mixed and then filtered through a membrane filter with a pore size of 30 μm to prepare a sol C.

The above-mentioned sol A, B, and CQPH values and liquid temperatures were all approximately the same, and were 4.5.20°C, respectively. Note that ■ to ■ were conducted in a clean room of cleanliness class 100.

■ Gelling ~ Drying Next, pour the above sol A into 50 polypropylene containers (inner dimensions 200 x 200 x 100 mm) each at 3 ρ.
The container was covered with a lid and gelatinized on a sealed surface to produce 16 wet gels.

In the same manner, 16 wet gels each were prepared from Sol B and Sol C.

Next, the obtained 48 wet gels were aged for 3 days at 30°C in a sealed closed state, and then the lid was replaced with a lid with a porosity of 0.4% and the temperature was raised from room temperature to 65°C. When the dry gel was heated and then kept at this temperature for 10 to 14 days, a stable dry gel that did not crack even when left in the air was produced as shown in Table 2.
was obtained with the yield shown in .

Table 2 ■ Sintering The three types of dry gels mentioned above were put into a sintering furnace, and the heating rate was 30.
It was heated from 30@C to 200@C at @C/hr and held at this temperature for 5 hours, then heated to 300°C and held for 5 hours to perform desorption water treatment.

Subsequently, the temperature was increased from 300@C to 700 at a heating rate of 30°C/hr.
After heating to °C and holding at mrx for 20 hours,
Heated from 700°C to 900°C at a heating rate of 30°C/hr, held at this temperature for 10 hours, and then heated at a heating rate of 30°C/hr.
Heat from 900°C to too@c at °C/hr,
This temperature was maintained for 10 hours to perform decarbonization, dechlorination ammonium treatment, and acceleration treatment of dehydration condensation reaction.

After this, while flowing He gas into the furnace, the heating rate was 30'''.
It was heated to 1250°C at a rate of C/hr and held at this temperature for 2 hours to perform a pore-closing treatment.

After that, it was heated to 1400°C at a heating rate of 60°C/hr, and when it was held at this temperature for 1 hour, it became non-porous.
A transparent glass body was obtained with a yield of 100%.

All the results of physical property analysis of this glass body were consistent with those of quartz glass.

The quartz glass produced in this example had no foreign substances such as bubbles and was of extremely high quality. Furthermore, the spectral characteristics in the ultraviolet and visible regions were flat, and the quality was such that it could be used as a photomask substrate used in IC manufacturing.

(Effects of the Invention) The glass thus produced according to the present invention is produced by using a solution in which fine silica particles, which are a product of the hydrolysis reaction of an alkyl silicate under a basic catalyst, are dispersed, and A high-purity sol prepared by mixing with a reaction solution at a predetermined ratio is gelled to produce a wet gel, and the wet gel is dried to form a porous dry gel and then sintered to form transparent glass. It is possible to produce high-quality glass with extremely low levels of impurities such as metal ions, crystals, bubbles, and irregularly shaped foreign substances. It is possible to stably produce high-quality glass at a high yield.Also, AJ2.T
By adding various elements such as i, Ge, Na, Ca, Mg, Li, and Te at the time of sol preparation, it is easy to produce high-quality multicomponent glasses of various compositions.

that's all 1 person from Seiko Even Co., Ltd. Agent: Patent Attorney Mogami and 1 other person N2'

Claims (1)

[Claims] (1) In the production of glass by the sol-gel method using alkyl silicate as the main raw material, a solution in which fine silica particles, which are a product of the hydrolysis reaction of alkyl silicate under a basic catalyst, are dispersed (hereinafter referred to as the first liquid) and a hydrolysis reaction of an alkyl silicate using an acidic catalyst (hereinafter referred to as the second liquid) in a predetermined ratio, and gelling a sol prepared to prepare a wet gel. A method for producing quartz glass that transmits short wavelength laser light, comprising the steps of drying the wet gel to produce a dry gel, and sintering the dry gel to produce a transparent glass body.