JPS58161929A - Manufacture of high purity quartz glass plate - Google Patents

Abstract

PURPOSE:To continuously manufacture a high-purity quartz glass plate, by depositing fine particles of oxide forming glass on the slender quadrilateral bottom of a substrate, growing them, and heating the grown particles to a high temp. while pulling them up to successively convert a layer of the particles into transparent glass. CONSTITUTION:A burner 2 having a triple-tubed structure consisting of a nozzle 7 for SiCl4 as a gaseous starting material, a nozzle 8 for a combustion gas, and a nozzle 9 for O2 as a gaseous combustion improver is placed under the bottom of a substrate 1. The length L1 of the major side of the substrate 1 is about 1.5-2 times the width of a quartz glass plate to be manufactured, and the length L2 of the minor side is about 1.5-2 times the thickness of the plate. While moving the substrate 1 upward and the burner 2 back and forth in the direction of the major side of the substrate 1 (arrow 240), fine glass particles 4 formed by a flame decomposition reaction with a burner 2 are sprayed on the bottom of the substrate 1 and successively deposited. The resulting flat porous layer 5 is then vitrified by heating with a pair of rodlike heaters 3, 3 to manufacture a quartz glass plate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of quartz or quartz-based glass plates, and particularly to a method for continuously producing optically excellent glass plates made of high purity wax.

Compared to multi-component glass (mainly containing alkali), quartz glass ■ Has a small coefficient of thermal expansion, so it is resistant to rapid temperature changes ■ Has a high softening point, so it can be used at high temperatures ■ It is chemically stable ■ Impurities It has advantages such as good light transmittance over a wide wavelength range from ultraviolet to infrared, and is widely used in fields such as semiconductors, optical instruments, and optical communication devices. Among these uses, the demand for quartz glass plates as optical window materials and photomask substrates has increased in recent years, and in order to fully demonstrate their functions, it is necessary to use quartz glass with higher precision and higher purity than ever before. The board is stably supplied with seed molds.

The conventional method for manufacturing quartz glass plates is to first melt pulverized natural quartz powder in an electric furnace, pull out a quartz glass tube from around a die at the bottom of the furnace, and then cut the quartz glass tube open to make the plate. A common method is to form a quartz glass plate into a shape and then cut it into appropriate dimensions to obtain a quartz glass plate.

Although the above method for producing quartz glass plates uses low-cost raw materials,
■ Impurities such as Al and Na in natural quartz remain on the final product, the quartz glass plate, reducing the transmittance at short wavelengths and causing coloration due to radiation exposure. ■The process is complicated.■It is necessary to study both sides to achieve the final optical surface.

Due to these problems, it is difficult to obtain a high-precision, high-purity quartz glass plate at low cost.

As a way to solve these problems, high-purity 5.
Oxyhydrogen burner or plug using iC14? )-1
One possible method is to create a quartz glass ingot with few impurities, crush it, melt it in an electric furnace, and pull out the quartz glass tube, but the process is complicated and impurities get mixed in during the crushing process. Such problems cannot be solved.

There is also a method of directly cutting a high-purity quartz glass ingot created using the same method as above to obtain a quartz glass plate of appropriate dimensions.A high-purity quartz glass plate can be obtained, and the process is considerably simplified. Although there are some advantages, the ingots obtained by the above method are usually cylindrical, and when obtaining, for example, a square quartz glass plate from this cylindrical ingot, there is a large material loss, and even just cutting it causes a large material loss. This also has the disadvantage of increasing the amount of expensive diamond cutters used.

As described above, the method of producing a quartz glass plate using conventional technology is to obtain a quartz glass plate by cutting a quartz glass tube or cutting an ingot, and it is possible to obtain a quartz glass plate directly from raw materials. Therefore, the process becomes complicated and it is difficult to say that it is suitable for continuous production.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and provides a method for manufacturing a high-purity quartz glass plate relatively easily and continuously.

In the method according to the present invention, a glass-forming raw material supply nozzle and a burner are arranged toward the bottom surface of a base material whose bottom surface has an elongated quadrilateral shape, and flame hydrolysis is performed while moving the base material relatively upward. Glass-forming oxide fine particles are caused to adhere and grow on the bottom surface of the substrate by reaction, and the fine particle layer is sequentially turned into transparent glass by heating at a high temperature with a heating element provided above the growth surface.

The bottom shape of the base material used in the present invention is determined according to the width and thickness of the quartz glass plate to be manufactured, but it is made transparent by heating the fine particle deposit layer (porous layer) produced by the flame hydrolysis reaction at high temperature. Because it shrinks in the width and thickness directions during the vitrification process, the lengths of the long and short sides of the base material should be 1.5 to 10 times the width and thickness of the quartz glass plate to be manufactured, taking into account this shrinkage. It is desirable to choose within twice the range.

Also, if the length ratio between the long side and the short side is too small, it will be necessary to cut the long side in the thickness direction after molding, so the long side should be selected to be at least 10 times the short side, preferably 15 times. In addition, if the length of the short side of the bottom surface of the base material is too small, it will be difficult to control the thickness of the fine particle deposit layer to a constant value.
It is desirable to set it to m/rn or more.

Next, an example of a practical aspect of the present invention will be explained based on the drawings.

As shown in FIG.
In the container 2/2 filled with C14j / /, a carrier gas 2/J such as vcrlp element or argon is introduced, and
Gas containing IC14 steam is supplied via piping 210 to the raw material supply nozzle 7 located at the center of the burnerco having a triple pipe structure. A burner nozzle lrK is arranged in an annular manner on the outside of this raw material supply nozzle 7, and a combustion gas 20 for hydrogen, butane, etc. is installed in the burner nozzle 9, which is arranged in an annular manner further outside this nozzle zone. is supplied, and fine particles l are produced by a flame hydrolysis reaction.
is generated.

Nao, 5ic14 is usually used as the raw material for forming glass, but it is not limited to this as long as it has a high vapor pressure, and it goes without saying that hydrogen compounds, organometallic compounds, etc. are also acceptable. stomach.

Above the burner 2, a plate-shaped base material 1 made of, for example, quartz is arranged substantially vertically, and this base material 1 is pulled upward at a constant speed via a pulling drive mechanism located above (not shown).

Long side length Ll and short side length L at the bottom of the base material
2 is the cap and wall thickness of the quartz glass plate to be manufactured.
．． It is selected to be between j times and 2.0 times.

The burner is parallel to the long side of the bottom surface of the base material l at 2110 degrees.
As a result, glass particles q generated by the flame hydrolysis reaction are sequentially deposited on the bottom surface of the substrate/, and these particles are fused together to form a flat porous layer j.

A pair of rod-shaped heaters 3 for high-temperature heating are provided between the nozzle and the base material 1 so as to sandwich the movement path of the base material 1, and the porous layer 3 is heated by these heaters 3 and 3 sequentially from the upper end. The quartz glass plate 6 is made into a transparent glass and formed into a continuous band shape.

Since the synthesis of the above porous layer j utilizes a flame hydrolysis reaction, many OH groups are mixed in at the beginning, but they are volatilized as H2O in gases such as HetAr during sintering. In the finally obtained transparent quartz glass plate, only a few tens of ppm of OH groups remain. Even more porous layer! When sintering, by flowing chlorine gas or halogen gas such as thionyl chloride, the OH groups in the glass become s S 1-OH+Ol 2→-0-5i
-0-3i--1-JHOJ reaction, O
It is also possible to obtain a quartz glass plate substantially free of H groups.

In addition, an appropriate amount of additives such as Ti may be added to the glass forming raw material.
t Ge + B + P + Sn t Al +
Refractive index of a glass plate obtained by adding a compound such as Gar Pb.

It is possible to adjust properties such as expansion coefficient and viscosity.

A desired lath plate can be obtained by cutting the thus obtained ribbon-shaped quartz or quartz-based glass plate into appropriate dimensions.

In the above description, a burner and a separate raw material supply nozzle may be used as a method for supplying raw materials for glass formation. In addition, as shown in Figure 1, the burners are arranged at intervals in the long side direction of the base material l, and the burners are arranged at intervals in the direction parallel to the said side.
When K short-period vibration is applied, it is easy to obtain a porous layer j having a large width.

As described above, according to the method of the present invention, quartz or quartz-based glass can be directly formed using volatile glass forming raw materials, and the process is relatively simple compared to the conventional technology. Glass plates of this type can be obtained at low cost.

[Example 1] In the apparatus shown in FIG. 1, 3! The raw material 5iC14 in a container maintained at °C was bubbled with a carrier gas of argon (Ar) and supplied to a quartz burner via a pipe.

Carrier gas Ar: 10occi mint 5xC1
4: J j 0CCZ minutes from the raw material supply nozzle 7 at the center of the burner, combustion gas) 12: 5ooo00/minute from the burner nozzle! and auxiliary combustion gas 02:9
00 CCj/min was supplied from the outermost layer nozzle 9, respectively. 200 x 30 x 101fi as pulling base material
Using a + quartz glass plate, a 5i0251
Particles were generated and a porous layer j was grown. The cross-sectional size of this porous layer j is approximately 000 x 10 mm, and the bulk density is approximately 0,000 g.
The growth rate was approximately 2.3 nm/min.
By heating this porous layer with a pair of rod-shaped graphite resistance heaters to approximately /600'CK, the width of the porous layer is 3 mm and the thickness is 1.
Transparent quartz glass plates of lrnm were obtained continuously.

Note that the OH group content in the glass could be reduced to about 110 PP by flowing He gas during the transparentization. The quartz glass plate thus obtained had a substantially flat surface, and there were no particular problems in ordinary optical use.

[Postal example-]

Using 5iC1+ and TiCl4 as raw materials, each was bubbled with carrier gas lr and mixed in a pipe, then jQ
It was evenly fed to j quartz burners arranged with a pitch of IIIm. The total amount of raw materials supplied to j quartz burners is carrier gas Ar: 220000 y S
iO/a: 1000cc/min, TiCl4:
5iC14 containers in 3jCG' minutes, T
iCl4 was kept at SO°C. In addition, H2 is used as a combustion gas.
: 101/min and auxiliary combustion gas 02:1Sl/min were supplied, respectively. A 30x30xjIII+ quartz glass plate was used as the base material, and Kj quartz stock burners parallel to the long side direction of the bottom surface were returned to the pitch interval of the burners for a short period while the above raw materials were subjected to a flame hydrolysis reaction. Fine particles were generated, and a porous layer was grown on the bottom surface of the base material. The cross section of this porous layer is approximately 2×7, and the bulk density is approximately 0.1 gg/C.
l113. The growth rate was 2.11/min. By heating this porous layer with oil of approximately 100"cK using a pair of rod-shaped graphite resistance heaters installed above, approximately t2ox
A transparent quartz-based glass plate with a cross section of t, smm was continuously obtained.

In addition, by mixing a small amount of (12 gas) with KHe gas at the time of transparency, it was possible to reduce the OH groups in the glass to less than / PPm.The silica-based glass plate thus obtained contained TiO2, It had the characteristics that its refractive index was higher than that of pure silica glass, and its expansion coefficient was lower than that of a quartz glass plate.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the invention, and FIG. 2 is a perspective view showing another embodiment of the invention. l...Base material 2...Bar
f -3・・・・・・・Heater l・・・・・・・
・Glass fine particles 3...Porous layer 6...
......Quartz glass plate 7...... Raw material supply nozzle

Claims (1)

[Claims] A glass forming raw material supply nozzle and a burner are reciprocably movable in the long side direction of the bottom surface toward the bottom surface of the base material whose bottom surface has an elongated quadrilateral shape, or are arranged at intervals in the long side direction.
Glass-forming compound fine particles are deposited and grown on the bottom surface of the substrate by a flame hydrolysis reaction while moving the substrate relatively upward, and heated at high temperature with a heating element provided above the growth surface. A method for manufacturing a high-purity quartz glass plate, comprising sequentially converting the fine particle layer into transparent glass by: