JP2022059572A - Black quartz glass and method for manufacturing the same - Google Patents

Abstract

To provide: black quartz glass excellent in light-shielding, free from risk of the occurrence of contamination in a use process, and sufficient in color uniformity even when enlarged and capable of manufacturing a large-sized ingot; a method capable of manufacturing the black quartz glass with excellent productivity even in a large-sized ingot; and a product manufactured from the black quartz glass.SOLUTION: Black quartz glass includes Si in amount of 0.5-10 mass%, SiO in an amount of 0.1-5 mass%, and the remainder consisting of SiO2 and has an SCE reflectance of 10% or less at a wavelength of 350-750 nm. A method for manufacturing the black quartz glass comprises: pressure-molding powder obtained by mixing and compacting a Si powder of 0.5-10 mass% and an SiO powder of 0.1-5 mass% with (1) fumed silica, (2) the mixed powder of the fumed silica and synthetic silica powder, or (3) the mixed powder of the fumed silica, the synthetic silica powder, and spherical silica; and heating the pressure-molded product in the atmosphere to sinter the fumed silica. A product includes a black quartz glass member using the black quartz glass.SELECTED DRAWING: None

Description

The present invention relates to black quartz glass and a method for producing the same. More specifically, the present invention comprises a quartz glass cell for optical analysis, a black quartz glass that can be used as a light-shielding member of a semiconductor manufacturing device or an infrared heating device, an infrared heat absorption / heat storage member, and the black quartz glass. It relates to a manufacturing method obtained efficiently. Furthermore, the present invention relates to the product made of black quartz glass of the present invention.

Quartz glass is used in various applications such as lighting equipment, optical equipment parts, semiconductor industrial parts, physics and chemistry equipment, etc. by taking advantage of its good light transmission, low thermal expansion, and chemical resistance from the ultraviolet region to the infrared region. There is. Among them, black glass, which is made by adding a small amount of transition metal oxide to quartz glass, is used for parts that require local shading, and is bonded to transparent quartz glass by thermocompression bonding, etc., and quartz for optical analysis. It is used for optical equipment parts such as glass cells. However, in recent years, the miniaturization / thinning of parts has progressed, and the conventional black glass may not have sufficient light-shielding property. Therefore, black quartz glass having higher light-shielding property and easily bonded to transparent quartz glass is required. ing.

Quartz glass also has features such as high heat resistance and high chemical purity, and is often used in jigs for semiconductor manufacturing. However, in recent years, heating loss has become a problem in the heat treatment process of the semiconductor manufacturing process, and in the heating process using infrared light, it is efficient to shield members and objects to be heated from infrared irradiation other than the object to be heated. Infrared heat absorption / heat storage members for heating are required. For this reason, it is required to develop black quartz glass that effectively shields infrared rays, has excellent infrared heat absorption / heat storage properties, can manufacture large members, and does not contain metal impurities that cause process contamination. ing.

Conventionally, the following are known as black glass containing silica as a main component.

For example, Patent Document 1 proposes a method for producing black quartz glass by mixing quartz glass powder and niobium pentoxide, converting niobium pentoxide into niobium pentoxide, and then heating to 1800 ° C. or higher to reduce and melt the quartz glass powder. ing.

In Patent Document 2, a volatile organic silicon compound that can be a carbon source is subjected to a gas phase reaction on silica porous glass and then heated and fired at a temperature of 1200 ° C. or higher and 2000 ° C. or lower to contain carbon derived from the organic silicon compound. It has been proposed to produce quartz glass.

In Patent Document 3, a fused silica powder obtained by pulverizing fused silica glass and a silicon-containing powder are wet-mixed, then molded by a casting method and dried, and the obtained molded body has a sintering temperature lower than the melting temperature of silicon. It has been proposed to produce black quartz glass as a composite material having a matrix of fused silica in which regions of Si in elemental form are embedded by heating at 1,350 to 1435 ° C.

Patent Document 4 proposes a colored glass sintered body in which carbon is dispersed as colored particles of 0.1% to 30% by volume in a matrix of the glass sintered body.

Japanese Unexamined Patent Publication No. 2014-94864 (Claims, etc.) Japanese Unexamined Patent Publication No. 2013-1628 (Claims, etc.) JP-A-2020-73440 (Claims, etc.) Japanese Patent Application Laid-Open No. 2003-146676 (Claims, etc.)

However, the black quartz glass described in Patent Document 1 may not have sufficient color uniformity when the size is increased, a temperature of 1800 ° C. or higher is required for production, and it is necessary to use a high-grade material for the furnace material and the heater. At the same time, it requires a large amount of energy for heating, and there is a problem in productivity. In addition, it has been difficult to apply it to the semiconductor manufacturing field because the contained niobium compound may cause contamination in the process of being used.

The black quartz glass described in Patent Document 2 also has a problem in color uniformity, and it is difficult to increase the size. A non-oxidizing atmosphere is required for manufacturing, the structure of the furnace is complicated, the operation is complicated, and there is a problem in productivity. It was also difficult to increase the size due to the structure of the furnace. In addition, it is difficult to apply it to the semiconductor manufacturing field because the contained carbon may be generated in the process of using it as particles and cause contamination.

The black quartz glass of the kind described in Patent Document 3 may not have sufficient color uniformity when the size is increased. Further, there is a problem in increasing the size due to the limitation of casting molding. In addition, the casting molding and drying operations are complicated and it takes a long time to manufacture, and since sintering requires heating at a temperature of 1350 ° C. or higher, it is necessary to use high-grade materials for the furnace material and heater. At the same time, a large amount of energy was required for heating, and there was a problem in productivity.

The black quartz glass of the kind described in Patent Document 4 may not have sufficient color uniformity when the size is increased, and further, when the size is increased, the risk of breakage when sintering the molded body increases, and the size is large. There was a problem that black quartz glass could not be obtained. In addition, it is difficult to apply it to the semiconductor manufacturing field because carbon is generated in the process of using it as particles and may cause contamination.

The problem to be solved by the present invention is that it has excellent light-shielding property, does not cause contamination in the process used, has sufficient color uniformity when it is enlarged, and can produce a large-sized ingot. It is to provide a black quartz glass.

Another object of the present invention is to provide a method for producing black quartz glass, which solves the above-mentioned problems, with excellent productivity even with a large ingot.

A further object of the present invention is to provide an optical component such as a spectroscopic cell manufactured by using the black quartz glass, a black quartz glass product such as a light-shielding member for a semiconductor manufacturing apparatus and an infrared heat absorption / heat storage member. ..

As a result of diligent studies to solve the above problems, the present inventors have found a black quartz glass that does not substantially contain metal impurities other than Si and O and does not cause contamination in the process used. It can be obtained in a system in which fine particles of Si and SiO are dispersed in quartz glass at a specific concentration, and further, this black quartz glass has excellent light-shielding properties and is uniform in color when it is enlarged. We have found that the properties are sufficient and the productivity is high, and have completed the present invention.

The present invention is as follows.
[1]
It is a glass containing 0.5 to 10% by mass of Si and 0.1 to 5% by mass of SiO, and the balance is SiO ₂ (hereinafter referred to as quartz glass), and has an SCE reflectance at a wavelength of 350 nm to 750 nm. Black quartz glass that is 10% or less.
[2]
L ^* a ^* b ^* The black quartz glass according to [1], wherein the brightness L ^* of the display system is 30 or less, the absolute value of saturation a ^* is 3.5 or less, and the absolute value of b ^* is 4 or less.
[3]
The black quartz glass according to [1] or [2], wherein the content of metal impurities other than the Si element is 1 ppm or less, respectively.
[4]
The black quartz glass according to any one of [1] to [3], which satisfies any one or more of the following physical properties (a) to (f).
(A) The density is 2.15 / cm ³ or more and 2.3 g / cm ³ or less.
(B) The specific heat at a temperature of 500 ° C. is 1090 J / kg · K or more and 1130 J / kg · K or less.
(C) The thermal diffusivity at a temperature of 500 ° C. is 7 × 10 ^-7 m ² / s or more and 8 × 10 ^-7 m ² / s or less.
(D) The thermal conductivity at a temperature of 500 ° C. is 1.5 W / mK or more and 2.1 W / mK or less.
(E) The coefficient of thermal expansion in the range of 30 ° C to 600 ° C is 2 × 10 ^-7 / ° C or higher and 12 × 10 ^-7 / ° C or lower.
(F) The light transmittance at a wavelength of 200 nm to 3000 nm is 0.5% or less at a thickness of 1 mm.
[5]
At least a part of Si contained in quartz glass is in the form of particles, and the diameter of the particulate matter is 5 to 10 μm at D ₅₀ , 1 μm or more at D ₁₀ , and 30 μm or less at D ₉₅ , [1] to [4]. ] The black quartz glass according to any one of the items.
[6]
At least a part of SiO contained in the quartz glass is in the form of particles, and the diameter of the particulate matter is 5 to 15 μm in D ₅₀ , 1 μm or more in D ₁₀ , and 35 μm or less in D ₉₀ , [1] to [5]. ] The black quartz glass according to any one of the items.
[7]
(A) Is the portion of SiO ₂ a sintered body of fumed silica?
(B) The portion of SiO ₂ is a baked synthetic silica powder in which fumed silica is 30 to 60% by mass, the balance is particle size, D ₅₀ is 60 to 100 μm, D ₁₀ is 40 μm or more, and D ₉₅ is 180 μm or less. The part of (c) SiO ₂ that is a bound body is 30 to 60% by mass of fumed silica, 5 to 15 μm for D ₅₀ , 1 μm or more for D ₁₀ , and 5 to 5 for spherical silica with D ₉₅ of 70 μm or less. Any of [1] to [6], which is a sintered body of synthetic silica powder having 25% by mass, the balance having a particle size of D ₅₀ of 60 to 100 μm, D ₁₀ of 40 μm or more, and D ₉₅ of 180 μm or less. The black quartz glass according to item 1.
[8]
The powder obtained by mixing and compacting 0.5 to 10% by mass of Si powder and 0.1 to 5% by mass of SiO powder in fumed silica is pressure-molded, and the pressure-molded product is heated to the maximum temperature in the atmosphere. The fumed silica is sintered by heating at 1200 to 1300 ° C. to obtain the black quartz glass according to any one of [1] to [6] or the black quartz glass according to (a) of [7]. Including or
(2) 0.5 to 10 mass of synthetic silica powder containing 30 to 60% by mass of fumed silica, the balance having a particle size of 60 to 100 μm for D ₅₀ , 40 μm or more for D ₁₀ and 180 μm or less for D ₉₅ . The powder obtained by mixing and compacting% Si powder and 0.1 to 5% by mass SiO powder is pressure molded, and the pressure molded product is heated in the air at a maximum temperature of 1250 to 1320 ° C. and baked. Containing or combining to obtain the black quartz glass according to any one of [1] to [6] or the black quartz glass according to (b) of [7], or
(3) Fused silica is 30 to 60% by mass, D ₅₀ is 5 to 15 μm, D ₁₀ is 1 μm or more, D ₉₅ is 70 μm or less, 5 to 25% by mass, and the balance is particle size and D ₅₀ is. A powder obtained by mixing and compacting 0.5 to 10% by mass of Si powder and 0.1 to 5% by mass of SiO powder into synthetic silica powder having 60 to 100 μm, D ₁₀ of 40 μm or more, and D ₉₅ of 180 μm or less. The black quartz glass according to any one of [1] to [6] or [ 7] A method for producing black quartz glass, which comprises obtaining the black quartz glass according to (c).
[9]
Fused silica has a tap bulk density of 0.03 to 0.08 g / cm ³ , a BET specific surface area of 50 to 100 m ² / g, an OH group concentration of 0.5 to 1.0% by mass, and metal impurities other than Si. The method for producing black quartz glass according to [8], wherein the content of each of the above is 1 ppm or less, which satisfies at least one of them.
[10]
The Si powder has a particle diameter D ₅₀ of 5 to 10 μm, D ₁₀ of 1 μm or more, and D ₉₅ of 30 μm or less, and the SiO powder has a particle diameter of D ₅₀ of 3 to 15 μm, D ₁₀ of 1 μm or more, and D ₉₀ . The method for producing black quartz glass according to [8] or [9], which is 35 μm or less.
[11]
The mixing compaction is carried out so that the tap bulk density of the powder obtained by the mixing compaction is 5 to 20 times the tap bulk density of fumed silica, according to any one of [8] to [10]. How to make black quartz glass.
[12]
The method for producing black quartz glass according to any one of [8] to [11], wherein the heating sintering time in the atmosphere is 0.5 to 5 hours.
[13]
A product containing a black quartz glass member using the black quartz glass according to any one of [1] to [7].
[14]
The product according to [13], wherein the black quartz glass member is an optical component, a light-shielding member, or an infrared heat absorption / heat storage member.
[15]
The product according to [14], wherein the optical component is a spectroscopic cell, a reflector of a projector, or a connector of an optical fiber, and the light-shielding member is a light-shielding member of a semiconductor manufacturing device or an infrared heating device.

According to the present invention, there is a black quartz glass having excellent light-shielding properties, sufficient color uniformity when the size is increased, high productivity, and no risk of causing contamination in the process of use. Provided. Further, according to the present invention, there is provided a method capable of producing the black quartz glass with high productivity by using a heating step at a relatively low temperature. In addition, since the black quartz glass of the present invention is excellent in light-shielding property, it can be suitably used for a quartz glass cell for optical analysis, a light-shielding member of a semiconductor manufacturing apparatus or an infrared heating apparatus, and an infrared heat absorption / heat storage member.

<Black quartz glass>
The black quartz glass of the present invention will be described.
The black quartz glass of the present invention is a quartz glass containing 0.5 to 10% by mass of Si and 0.1 to 5% by mass of SiO, and the balance is SiO ₂ . At least a part of Si is a simple substance composed of a plurality of Si atoms, and at least a part of Si exists in quartz glass as a particle substance made of Si which is a simple substance. SiO is silicon monoxide, and at least a part of SiO is present in quartz glass as particulate matter composed of SiO.

If Si is less than 0.5% by mass and SiO is less than 0.1% by mass, the brightness L * becomes large, which is not preferable, and the SCE reflectance also becomes large, which is not preferable. If Si exceeds 10% by mass and SiO exceeds 5% by mass, sintering of the raw material is hindered during preparation, which causes a decrease in the mechanical strength of the quartz glass of the present invention as a sintered body. Si is preferably in the range of 0.5 to 5% by mass, more preferably 0.5 to 3% by mass. SiO is preferably in the range of 0.2 to 2% by mass, more preferably 0.3 to 2% by mass, and the balance is SiO ₂ .

The black quartz glass of the present invention has an SCE reflectance of 10% or less at a wavelength of 350 nm to 750 nm. The SCE reflectance at a wavelength of 350 nm to 750 nm is measured according to JIS Z 8722. When the SCE reflectance is 10% or less, excellent light-shielding property is exhibited. The SCE reflectance is preferably low, preferably 9% or less, and more preferably 8% or less, from the viewpoint of excellent light-shielding property. The lower limit of the SCE reflectance is not particularly limited, but can be 1%.

In the black quartz glass of the present invention, it is preferable that the brightness L ^* of the L ^* a ^* b ^* display system is 30 or less. When the brightness L ^* is 30 or less, not only color unevenness does not occur, but also a sufficient blackish color that does not cause light transmission, stray light, or scattering can be exhibited. Further, in the black quartz glass of the present invention, it is preferable that the absolute value of the saturation a ^* of the L ^* a ^* b ^* display system is 3.5 or less and the absolute value of b ^* is 4 or less. When the lightness L ^* , the saturation a ^* and the b ^* are in the above ranges, the color tone of the black quartz glass of the present invention becomes blacker, and the black quartz glass has a low SCE reflectance. The lightness L ^* is preferably 28 or less, and it is preferable that the absolute value of the saturation a ^* is 2.8 or less and the absolute value of b ^* is 3.7 or less because the color tone becomes blacker.

The black quartz glass of the present invention preferably has a content of metal impurities other than Si element of 1 ppm or less. If the content of metal impurities other than the Si element is more than 1 ppm, it may cause process contamination in the manufacture of semiconductors and the like. Further, in the field of optical analysis or the like, there is a possibility that the accuracy may be adversely affected by the generation of fluorescence or the like. The content of metal impurities other than the Si element can be analyzed by a method such as atomic absorption spectroscopy.

The black quartz glass of the present invention has a density in the range of 2.15 to 2.3 g / cm ³ . The density is almost the same as the theoretical density of transparent quartz glass with Si and SiO added. The density is preferably in the range of 2.17 to 2.27 g / cm ³ , and more preferably in the range of 2.18 to 2.25 g / cm ³ .

The black quartz glass of the present invention can have a specific heat of 1090 J / kg · K or more and 1130 J / kg · K or less at a temperature of 500 ° C. The specific heat at a temperature of 500 ° C. can be measured by the differential scanning calorimetry (DSC method). The specific heat is preferably in the range of 1095 J / kg · K or more and 1120 J / kg · K or less, and more preferably in the range of 1100 J / kg · K or more and 1114 J / kg · K or less.

The black quartz glass of the present invention can have a thermal diffusivity of 7 × 10 ^-7 m ² / s or more and 8 × 10 ^-7 m ² / s or less at a temperature of 500 ° C. The thermal diffusivity at a temperature of 500 ° C. can be measured by the flash method in accordance with JIS R 1611. The thermal diffusivity is preferably in the range of 7.2 × 10 ^-7 m ² / s or more, 7.9 × 10 ^-7 m ² / s or less, and more preferably 7.4 × 10 ^-7 m ² It is in the range of / s or more and 7.6 × 10 ^-7 m ² / s or less.

The black quartz glass of the present invention can have a thermal conductivity of 1.5 W / mK or more and 2.1 W / mK or less at a temperature of 500 ° C. The thermal conductivity at a temperature of 500 ° C. can be calculated by multiplying the density of the sintered body by the specific heat and the thermal diffusivity. The thermal conductivity is preferably in the range of 1.6 W / mK or more and 2.0 W / mK or less, and more preferably in the range of 1.7 W / mK or more and 1.9 W / mK or less.

The black quartz glass of the present invention can have a coefficient of thermal expansion of 2 × 10 ^-7 / ° C. or higher and 12 × 10 ^-7 / ° C. or lower at a temperature of 30 ° C. to 600 ° C. The coefficient of thermal expansion at a temperature of 30 ° C to 600 ° C can be measured by a thermomechanical analysis method (TMA method). The coefficient of thermal expansion is preferably in the range of 4 × 10 ^-7 / ° C or higher and 11 × 10 ^-7 / ° C or lower, and more preferably 6 × 10 ^-7 / ° C or higher and 10 × 10 ^-7 / ° C or lower. It is a range.

The black quartz glass of the present invention can have a light transmittance of 0.5% or less at a thickness of 1 mm at a wavelength of 200 nm to 3000 nm. The light transmittance at a wavelength of 200 nm to 3000 nm is measured by a spectrophotometer. When the light transmittance is 0.5% or less, excellent light-shielding property is exhibited. The light transmittance is preferably low, preferably 0.4% or less, and more preferably 0.3% or less from the viewpoint of excellent light-shielding property. The lower limit of the light transmittance is not particularly limited, but can be 0.01%.

Si is contained as a particulate substance in the black quartz glass of the present invention, and the particle diameter of the Si particulate substance is, for example, 5 to 10 μm for D ₅₀ , 1 μm or more for D ₁₀ , and 30 μm or less for D ₉₅ . SiO is contained as a particulate matter in the black quartz glass of the present invention, and the particle diameter of the SiO particulate matter is, for example, 3 to 15 μm for D ₅₀ , 1 μm or more for D ₁₀ , and 35 μm or less for D ₉₀ . When the particle size of the Si particulate matter is 5 μm or more at D ₅₀ and the particle size of the SiO particulate matter is 3 μm or more at D ₅₀ , the absolute values of the saturations a ^* and b ^* become small and the color tone becomes large. It becomes blacker and is preferable. When the particle diameter of the Si particulates is 10 μm or less at D ₅₀ and the particle diameter of the SiO particles is 15 μm or less at D ₅₀ , the brightness L ^* and SCE reflectance are equal to or less than the predetermined values, which is excellent. It becomes a black quartz glass having a light-shielding property, and the raw material silica can be easily sintered when preparing the black quartz glass, and there is a tendency to obtain a black quartz glass which is a sintered body having excellent mechanical strength. When the particle diameter of the Si particulate matter is 1 μm or more at D ₁₀ and the particle diameter of the SiO particulate matter is 1 μm or more at D ₁₀ , the absolute values of the saturations a ^* and b ^* tend to be small, which is preferable. .. When the particle size of the Si particulates is 10 μm or less at D ₅₀ and the particle size of the SiO particles is 15 μm or less at D ₅₀ , the sintering of the raw material silica proceeds satisfactorily during the preparation of black quartz glass. There is a tendency to obtain black quartz glass, which is a sintered body having excellent mechanical strength.

The black quartz glass of the present invention is produced by using fumed silica as a sintered material, as will be described later. Fumed silica is fine powdered silica obtained by burning silicon tetrachloride gas or the like in a gas phase. Since fumed silica has a small particle size of 10 to 30 nm, it generally has a very low bulk density and is not suitable for granulation or molding. Normally, the density of the sintered body obtained by sintering is small, and it is used as quartz glass. Not satisfactory. However, in the present invention, (1) fumed silica in which Si particles and SiO particles are dispersed at a specific concentration, or (2) a mixed powder of fumed silica and synthetic silica powder, or (3). By sintering a mixed powder of fumed silica and synthetic silica powder and spherical silica, surprisingly, a quartz glass having a density almost equal to the theoretical density obtained by adding Si and SiO to the quartz glass was obtained. Moreover, the obtained quartz glass was a black quartz glass having an SCE reflectance of 10% or less. As will be described later, the fumed silica used as a raw material has a tap bulk density of 0.03 to 0.08 g / cm ³ , a BET specific surface area of 50 to 100 m ² / g, and an OH group concentration of 0.5 to 1.0% by mass. And / or the fact that the fumed silica has a content of metal impurities other than the Si element of 1 ppm or less, a quartz glass having a density substantially equal to the theoretical density obtained by adding Si and SiO to the quartz glass can be obtained. Is preferable from the viewpoint that black quartz glass satisfying characteristics such as SCE reflectance can be produced even with a large ingot.

<Manufacturing method of black quartz glass>
The method for producing the black quartz glass of the present invention will be described.
The method for producing black quartz glass of the present invention is (1) fumed silica, (2) a mixed powder of fumed silica and synthetic silica powder, or (3) a mixed powder of fumed silica and synthetic silica powder and spherical silica. The powder obtained by mixing and compacting 0.5 to 10% by mass of Si powder and 0.1 to 5% by mass of SiO powder is pressure-molded, and the pressure-molded product is heated in the air to fume. Includes sintering dosilica. The maximum temperature of this heating is in the range of 1200 to 1300 ° C. in the case of (1), and in the range of 1250 ° C. to 1320 ° C. in the case of (2) and (3). By this manufacturing method, the black quartz glass of the present invention can be obtained.

Synthetic silica powder is high-purity powdered silica obtained by hydrolyzing, drying, pulverizing, and calcining chemically purified silicon alkoxide. The spherical silica powder is a high-purity synthetic molten spherical silica obtained by reacting silicon tetrachloride gas or the like in a gas phase. By adding synthetic silica powder or synthetic silica powder and spherical silica to fumed silica, the structure of the sintered body can be made more uniform, and the heating time to the maximum temperature can be shortened.

In the production method of the present invention, (1) fumed silica, or (2) fumed silica and synthetic silica powder, or (3) fumed silica and synthetic silica powder and spherical silica powder, and a predetermined amount of Si powder and SiO. (1) fumed silica, or (2) fumed silica and synthetic silica powder, or (3) fumed in the form of dry powder with powder coexisting and Si particles and SiO particles substantially free of agglomeration. Uniformly mix with silica and synthetic silica powder and spherical silica powder. In this mixing, consolidation proceeds at the same time as the mixing, and a powder for pressure molding can be obtained. As used herein, the consolidation operation that proceeds at the same time as mixing is defined as mixing and consolidation.

In order to obtain powder for pressure molding by mixing and compacting, Si powder having a particle diameter of 5 to 10 μm at D ₅₀ , D ₁₀ of 1 μm or more, and D 95 of ₃₀ μm or less is 0.5 to 10% by mass. It is preferable to use SiO powder having a diameter of 3 to 15 μm for D ₅₀ , 1 μm or more for D ₁₀ , and 35 μm or less for D ₉₀ in a ratio of 0.1 to 5% by mass. In addition, in order to obtain a powder for pressure molding by mixing and compacting, the tap bulk density is 0.03 to 0.08 g / cm ³ , the BET specific surface area is 50 to 100 m ² / g, and the OH group concentration is 0.5 to 1. Fumed silica with 0% by mass and a content of metal impurities other than Si of 1 ppm or less, synthetic silica powder with a particle size of 60 to 100 μm at D ₅₀ , 40 μm or more at D ₁₀ and 180 μm or less at D ₉₅ , particle size It is preferable to use spherical silica having a D ₅₀ of 5 to 15 μm, a D ₁₀ of 1 μm or more, and a D ₉₅ of 70 μm or less. It is preferable to use these fumed silica, synthetic silica powder, and spherical silica from the viewpoint that quartz glass having a density substantially equal to the theoretical density obtained by adding Si and SiO to quartz glass can be obtained.

Further, synthetic silica powder having a particle size of 60 to 100 μm at D ₅₀ , 40 μm or more at D ₁₀ and 180 μm or less at D ₉₅ , and 5 to 15 μm at D ₅₀ , 1 μm or more at D ₁₀ and 70 μm at D ₉₅ . It is preferable to use the following spherical silica from the viewpoint of making the structure of the sintered body more uniform and shortening the heating time to the maximum temperature at the time of sintering. Further, when the raw material silica is fumed silica and synthetic silica powder, the fact that the fumed silica is 30 to 60% by mass and the balance is synthetic silica powder makes the structure of the sintered body more uniform and sintered. It is preferable from the viewpoint of shortening the heating time to the maximum temperature at the time of. In addition, when the raw material silica is fumed silica, synthetic silica powder and spherical silica powder, fumed silica is 30 to 60% by mass, spherical silica is 5 to 25% by mass, and the balance is synthetic silica powder. It is preferable from the viewpoint of making the structure of the sintered body more uniform and shortening the heating time to the maximum temperature at the time of sintering.

Generally, fumed silica is not suitable for sintering. However, the density of the sintered body obtained by pressure-molding the powder for pressure molding obtained by mixing and consolidating in this way and heating it in the air at a maximum temperature of 1200 to 1320 ° C. is almost the same. It is possible to reach the theoretical density, and black quartz glass having characteristics such as excellent SCE reflectance can be obtained.

The mixing compaction is preferably carried out so that the tap bulk density of the compacted powder is 5 to 20 times the tap bulk density of fumed silica. When the tap bulk density of the pressure molding powder is 5 times or more the tap bulk density of fumed silica, the density of the sintered body tends to increase. If the tap bulk density of the pressure molding powder is 20 times or less the tap bulk density of fumed silica, the strength of the molded body does not decrease. The tap bulk density of the pressure molding powder is preferably in the range of 6 to 15 times, more preferably 7 to 10 times, the tap bulk density of fumed silica. Mixing consolidation can be performed using a general mixing device such as a stirring type mixer, a ball mill, a locking mixer, a cross mixer, and a V type mixer.

The mixed compacted powder can be formed into a desired shape. As the molding method, a dry method such as a mold press molding usually used for molding ceramics, a cold hydrostatic press method, or the like can be used. The appropriate press pressure is, for example, 10 to 300 MPa. If it is 10 MPa or more, the molded product does not collapse and the yield at the time of molding can be maintained. If it is 300 MP or less, it is desirable that productivity is good and production cost can be suppressed without requiring large-scale equipment.

When the raw material silica is fumed silica, sintering is performed in the air at a maximum sintering temperature of 1200 to 1300 ° C, preferably 1240 to 1260 ° C. More preferably, it is carried out at 1240 to 1250 ° C. When the sintering temperature exceeds 1300 ° C., the brightness L ^* tends to increase and the SCE reflectance tends to increase. If the sintering temperature is less than 1200 ° C., there is a tendency that a sintered body having good density and bending strength cannot be obtained.

When the raw material silica is fumed silica and synthetic silica powder, sintering is performed in the air at a maximum sintering temperature of 1250 to 1320 ° C, preferably 1280 to 1310 ° C. More preferably, it is carried out at 1290 to 1300 ° C. When the sintering temperature exceeds 1320 ° C., the brightness L ^* tends to increase and the SCE reflectance also tends to increase. If the sintering temperature is less than 1250 ° C., there is a tendency that a sintered body having good density and bending strength cannot be obtained.

When the raw material silica is fumed silica, synthetic silica powder and spherical silica powder, sintering is performed in the atmosphere at a maximum sintering temperature of 1250 to 1320 ° C, preferably 1280 to 1310 ° C. More preferably, it is carried out at 1290 to 1300 ° C. When the sintering temperature exceeds 1320 ° C., the brightness L ^* tends to increase and the SCE reflectance also tends to increase. If the sintering temperature is less than 1250 ° C., there is a tendency that a sintered body having good density and bending strength cannot be obtained.

In any of the heating and sintering steps, the sintering time at the maximum temperature in the atmospheric furnace can be, for example, in the range of 0.5 to 5 hours. However, it can be adjusted as appropriate in consideration of the physical characteristics of the sintered body. If the sintering time is short and low, the density and bending strength tend to decrease. If the sintering time is too long, the productivity will decrease and the production cost will increase.

Through the above steps, the obtained black quartz glass ingot can be processed by a processing machine such as a band saw, a wire saw, or a core drill used in manufacturing a quartz member to obtain a black quartz glass product.

The black quartz glass thus obtained has no color unevenness and exhibits a sufficient blackish color that does not cause light transmission, stray light, or scattering, and is useful in the entire optical field. In addition, it has extremely high light shielding performance and can be bonded to transparent quartz glass, so that it is suitable for producing an optical analysis cell made of quartz glass.

The present invention includes a product including a black quartz glass member using the above-mentioned black quartz glass of the present invention. The black quartz glass of the present invention has a coefficient of thermal expansion as small as that of quartz glass when used in an environment where dimensional accuracy is required at high temperature, and other thermal characteristics are also equivalent to those of quartz glass. Therefore, the black quartz glass member of the present invention is useful as, for example, an optical component, a light-shielding member, or an infrared heat absorption / heat storage member. The optical component is, for example, a spectroscopic cell, a reflector of a projector, or a connector of an optical fiber, and the light-shielding member is, for example, a light-shielding member of a semiconductor manufacturing device or an infrared heating device. However, it is not intended to be limited to these members.

The black quartz glass of the present invention does not contain metal impurities and is particularly suitable as a member of a heat treatment apparatus used for semiconductor production. For example, in a wafer heat treatment device, the heat radiated to the outside of the furnace is efficiently shielded by forming the portion other than the surface that transmits infrared rays for heating with the black quartz glass of the present invention, and the energy efficiency is improved and the furnace is improved. It is possible to make the internal temperature distribution uniform.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the Examples.

The sample characteristics were measured as follows.
(1) The density of the sintered body was measured by the Archimedes method.
(2) The SCE reflectance was measured in accordance with JIS Z 8722 using a spectrocolorimeter after processing the sample to a thickness of 7 mm. The highest numerical value in the wavelength range of 360 to 740 nm is described.
(3) The brightness L * and saturation a ^* and b ^* of the L ^* a ^* b ^* display system were measured using a spectrocolorimeter according to JIS Z 8722.
(4) The specific heat was measured by the differential scanning calorimetry (DSC method) at a temperature of 500 ° C. after processing the sample into φ6 × 1 mmt.
(5) The thermal diffusivity was measured by processing a sample into φ10 × 1 mmt at a temperature of 500 ° C. by a flash method in accordance with JIS R1611.
(6) The thermal conductivity was calculated by the following equation under the condition of a temperature of 500 ° C.
Thermal conductivity = specific heat x thermal diffusivity x density of sintered body (7) The coefficient of thermal expansion is the thermomechanical analysis method (TMA method) under the conditions of processing a sample into 3 x 4 x 20 mmL and 30 to 600 ° C. Measured by.
(8) The light transmittance was measured in the range of 200 to 3000 nm by processing the sample to a thickness of 1 mm and using a spectrophotometer.

(Example 1)
Tap bulk density 0.06 g / cm ³ , BET specific surface area 85 m ² / g, OH group concentration 0.7 mass%, fumed silica with a content of metal impurities other than Si of 1 ppm or less, and a particle size of D ₅₀ . 2.0% by mass of Si powder having 7 μm, 4 μm of D ₁₀ and 11 μm of D ₉₅ , 0.5 mass% of SiO powder having a particle size of 10 μm at D ₅₀ , 5 μm at D ₁₀ and 20 μm at D ₉₀ . Was added, and the mixture was mixed and compacted with a ball mill without using a solvent. The obtained powder for pressure molding having a tap bulk density of 0.45 g / cm ³ was press-molded at 90 MPa and sintered at 1250 ° C. for 3 hours in the air.

The obtained black quartz glass has a density of 2.20 g / cm ³ , an SCE reflectance of 5.3% or less, an L ^* a ^* b ^* display system brightness L ^* of 20.6, and a saturation a ^* . 1.9 and b ^* are −0.6, the specific heat at a temperature of 500 is 1103 J / kg · K, and the thermal diffusivity at a temperature of 500 ° C. is 7.5 × 10 ^-7 m ² / s. The thermal conductivity at a temperature of 500 ° C. is 1.82 W / mK, the thermal expansion rate at a temperature of 30 to 600 ° C. is 9.4 × 10 ^-7 / ° C., and the light transmittance is 0. It was 12% or less. The obtained black quartz glass exhibited a sufficient blackish color without uneven color and did not cause light transmission, stray light, or scattering, and was visually confirmed to be uniform and aesthetically pleasing.

(Example 2)
Tap bulk density 0.06 g / cm ³ , BET specific surface area 85 m ² / g, OH group concentration 0.7 mass%, fumed silica with a content of metal impurities other than Si of 1 ppm or less, and a particle size of D ₅₀ . 1.0% by mass of Si powder having 8 μm, 3 μm of D ₁₀ and 20 μm of D ₉₅ , 1.0 mass% of SiO powder having a particle size of 10 μm at D ₅₀ , 5 μm at D ₁₀ and 20 μm at D ₉₀ . Was added, and the mixture was mixed and compacted with a ball mill without using a solvent. The obtained powder for pressure molding having a tap bulk density of 0.45 g / cm ³ was press-molded at 90 MPa and sintered at 1250 ° C. for 3 hours in the air.

The obtained black quartz glass has a density of 2.19 g / cm ³ , an SCE reflectance of 7.6% or less, an L ^* a ^* b ^* display system brightness L ^* of 25.2, and a saturation a ^* . 2.6 and b ^* are 3.3, the specific heat at a temperature of 500 is 1108 J / kg · K, the thermal diffusivity at a temperature of 500 ° C. is 7.5 × 10 ^-7 m ² / s, and the temperature is The thermal conductivity at 500 ° C. is 1.83 W / mK, the thermal expansion rate at a temperature of 30 to 600 ° C. is 8.3 × 10 ^-7 / ° C., and the light transmittance is 0.17 in the range of 200 to 3000 nm. It was less than%. The obtained black quartz glass exhibited a sufficient blackish color without uneven color and did not cause light transmission, stray light, or scattering, and was visually confirmed to be uniform and aesthetically pleasing.

(Example 3)
Tap bulk density 0.06 g / cm ³ , BET specific surface area 85 m ² / g, OH group concentration 0.7% by mass, fumed silica with a content of metal impurities other than Si of 1 ppm or less, 50% by mass, particle size D ₅₀ is 80 μm, D ₁₀ is 48 μm, D ₉₅ is 160 μm, and the synthetic silica powder having a content of metal impurities other than Si of 1 ppm or less is 50% by mass as a silica mixed powder, and the particle size is 6 μm at D ₅₀ . , D ₁₀ is 4 μm, D ₉₅ is 10 μm Si powder is 2.0 mass%, D ₅₀ is 10 μm, D ₁₀ is 5 μm, D ₉₀ is 20 μm SiO powder is 0.5 mass%. The particles were added in proportion, and the mixture was mixed and compacted with a ball mill without using a solvent. The obtained powder for pressure molding having a tap bulk density of 0.60 g / cm ³ was press-molded at 90 MPa and sintered at 1300 ° C. for 3 hours in the air.

The density of the obtained black quartz glass is 2.20 g / cm ³ , the SCE reflectance is 5.3% or less, the brightness L ^* of the L ^* a ^* b ^* display system is 18.2, and the saturation a ^* is 3. .2, b ^* is 2.1, the specific heat at a temperature of 500 is 1105 J / kg · K, the thermal diffusivity at a temperature of 500 ° C. is 7.5 × 10 ^-7 m ² / s, and the temperature is 500. The thermal conductivity at ° C is 1.81 W / mK, the thermal expansion rate at a temperature of 30 to 600 ° C is 9.0 × 10 ^-7 / ° C, and the light transmission is 0.14% in the range of 200 to 3000 nm. It was as follows. The obtained black quartz glass exhibited a sufficient blackish color without uneven color and did not cause light transmission, stray light, or scattering, and was visually confirmed to be uniform and aesthetically pleasing.

(Example 4)
Tap bulk density 0.06 g / cm ³ , BET specific surface area 85 m ² / g, OH group concentration 0.7% by mass, fumed silica with a content of metal impurities other than Si of 1 ppm or less, 40% by mass, particle size D ₅₀ is 80 μm, D ₁₀ is 48 μm, D ₉₅ is 160 μm, the content of metal impurities other than Si is 1 ppm or less, 42% by mass of synthetic silica powder, and the particle size is 11 μm for D ₅₀ and 3 μm for D ₁₀ . , D ₉₅ is 52 μm, and the content of metal impurities other than Si is 1 ppm or less, respectively. Spherical silica is 18% by mass in a silica mixed powder, and the particle size is 6 μm at D ₅₀ , 3 μm at D ₁₀ , and 13 μm at D ₉₅ . Si powder is 1.0% by mass, and SiO powder having a particle size of 5 μm at D ₅₀ , 2 μm at D ₁₀ and 9 μm at D ₉₀ is added at a ratio of 0.5% by mass, and a ball mill is used without using a solvent. The mixture was compacted with. The obtained powder for pressure molding having a tap bulk density of 0.79 g / cm ³ was press-molded at 90 MPa and sintered at 1300 ° C. for 3 hours in the air.

The density of the obtained black quartz glass is 2.20 g / cm ³ , the SCE reflectance is 5.2% or less, the brightness L ^* of the L ^* a ^* b ^* display system is 19.0, and the saturation a ^* is 2. .2, b ^* is 3.6, the specific heat at a temperature of 500 is 1112 J / kg · K, the thermal diffusivity at a temperature of 500 ° C. is 7.5 × 10 ^-7 m ² / s, and the temperature is 500. The thermal conductivity at ° C is 1.83 W / mK, the thermal expansion rate at a temperature of 30 to 600 ° C is 7.6 × 10 ^-7 / ° C, and the light transmission is 0.22% in the range of 200 to 3000 nm. It was as follows. The obtained black quartz glass exhibited a sufficient blackish color without uneven color and did not cause light transmission, stray light, or scattering, and was visually confirmed to be uniform and aesthetically pleasing.

(Comparative Example 1)
Tap bulk density 0.06 g / cm ³ , BET specific surface area 85 m ² / g, OH group concentration 0.7 mass%, fumed silica with a content of metal impurities other than Si of 1 ppm or less, and a particle size of D ₅₀ . Si powder having 7 μm, D ₁₀ of 4 μm, and D ₉₅ of 11 μm was added at a ratio of 0.5% by mass, and the mixture was mixed and compacted with a ball mill without using a solvent. The pressure molding powder was press-molded at 90 MPa and sintered at 1250 ° C. for 3 hours in the atmosphere.

The density of the obtained black quartz glass is as small as 2.09 g / cm ³ , the SCE reflectance is as large as 13.0% or less, and the brightness L ^* of the L ^* a ^* b ^* display system is also as large as 36.2. The saturation a ^* was 1.1 and b ^* was -1.7. There was color unevenness, which was insufficient to prevent light transmission, stray light, and scattering.

The present invention is useful in the field relating to black quartz glass. According to the present invention, it is possible to economically and efficiently provide a large-sized black quartz glass ingot having excellent light-shielding properties. The black quartz glass of the present invention can be suitably used for a quartz glass cell for optical analysis, a light-shielding member of a semiconductor manufacturing apparatus or an infrared heating apparatus, and an infrared heat absorption / heat storage member.

Claims (15)

It is a glass containing 0.5 to 10% by mass of Si and 0.1 to 5% by mass of SiO, and the balance is SiO ₂ (hereinafter referred to as quartz glass), and has an SCE reflectance at a wavelength of 350 nm to 750 nm. Black quartz glass that is 10% or less. The black quartz glass according to claim 1, wherein the brightness L ^* of the L ^* a ^* b ^* display system is 30 or less, the absolute value of the saturation a ^* is 3.5 or less, and the absolute value of b ^* is 4 or less. The black quartz glass according to claim 1 or 2, wherein the content of metal impurities other than the Si element is 1 ppm or less, respectively. The black quartz glass according to any one of claims 1 to 3, which satisfies any one or more of the following physical properties (a) to (f).
(A) The density is 2.15 / cm ³ or more and 2.3 g / cm ³ or less.
(B) The specific heat at a temperature of 500 ° C. is 1090 J / kg · K or more and 1130 J / kg · K or less.
(C) The thermal diffusivity at a temperature of 500 ° C. is 7 × 10 ^-7 m ² / s or more and 8 × 10 ^-7 m ² / s or less.
(D) The thermal conductivity at a temperature of 500 ° C. is 1.5 W / mK or more and 2.1 W / mK or less.
(E) The coefficient of thermal expansion in the range of 30 ° C to 600 ° C is 2 × 10 ^-7 / ° C or higher and 12 × 10 ^-7 / ° C or lower.
(F) The light transmittance at a wavelength of 200 nm to 3000 nm is 0.5% or less at a thickness of 1 mm. _{3 . _} The black quartz glass according to any one item. Claims 1 to 5, wherein at least a part of SiO contained in the quartz glass is in the form of particles, and the diameter of the particulate matter is 5 to 15 μm for D ₅₀ , 1 μm or more for D ₁₀ , and 35 μm or less for D ₉₀ . The black quartz glass according to any one item. (A) The portion of SiO ₂ is a sintered body of fumed silica, or (b) the portion of SiO ₂ is 30 to 60% by mass of fumed silica, the balance is the particle size, and D ₅₀ is 60 to 60. It is a sintered body of synthetic silica powder having 100 μm, D ₁₀ of 40 μm or more, and D ₉₅ of 180 μm or less, or (c) the portion of SiO ₂ is 30 to 60% by mass of fumed silica and 5 for D ₅₀ . Spherical silica of ~ 15 μm, D ₁₀ of 1 μm or more, D ₉₅ of 70 μm or less is 5 to 25% by mass, and the balance is particle size of D ₅₀ is 60 to 100 μm, D ₁₀ is 40 μm or more, and D ₉₅ is 180 μm or less. The black quartz glass according to any one of claims 1 to 6, which is a sintered body of synthetic silica powder. (1) A powder obtained by mixing and compacting 0.5 to 10% by mass of Si powder and 0.1 to 5% by mass of SiO powder in fumed silica is pressure-molded, and the pressure-molded product is placed in the atmosphere. The fumed silica is sintered by heating at a maximum temperature of 1200 to 1300 ° C. to obtain the black quartz glass according to any one of claims 1 to 6 or the black quartz glass according to claim 7 (a). Or (2) Synthetic silica powder with fumed silica in 30-60% by mass, the balance having a particle size of 60-100 μm for D ₅₀ , 40 μm or more for D ₁₀ and 180 μm or less for D ₉₅ , 0. .The powder obtained by mixing and compacting 5 to 10% by mass of Si powder and 0.1 to 5% by mass of SiO powder is pressure-molded, and the pressure-molded product is placed in the air at a maximum temperature of 1250 to 1320 ° C. The black quartz glass according to any one of claims 1 to 6 or the black quartz glass according to claim 7 (b) is obtained by heating and sintering, or (3) fumed silica. 30 to 60% by mass, D ₅₀ is 5 to 15 μm, D ₁₀ is 1 μm or more, D ₉₅ is 70 μm or less, 5 to 25 mass% of spherical silica, the balance is particle size, D ₅₀ is 60 to 100 μm, D ₁₀ is A powder obtained by mixing and compacting 0.5 to 10% by mass of Si powder and 0.1 to 5% by mass of SiO powder into a synthetic silica powder having a D 95 of 40 μm or more and a D ₉₅ of 180 μm or less is pressure-molded. The pressure-molded product is heated in the air at a maximum temperature of 1250 to 1320 ° C. and sintered to obtain the black quartz glass according to any one of claims 1 to 6 or the black color according to claim 7 (c). A method for producing black quartz glass, which comprises obtaining silica glass. Fused silica has a tap bulk density of 0.03 to 0.08 g / cm ³ , a BET specific surface area of 50 to 100 m ² / g, an OH group concentration of 0.5 to 1.0% by mass, and metal impurities other than Si. The method for producing black quartz glass according to claim 8, wherein the content of black quartz glass satisfies at least one of 1 ppm or less. The Si powder has a particle diameter D ₅₀ of 5 to 10 μm, D ₁₀ of 1 μm or more, and D ₉₅ of 30 μm or less, and the SiO powder has a particle diameter of D ₅₀ of 3 to 15 μm, D ₁₀ of 1 μm or more, and D ₉₀ . The method for producing black quartz glass according to claim 8 or 9, which is 35 μm or less. The black color according to any one of claims 8 to 10, wherein the mixing compaction is carried out so that the tap bulk density of the powder obtained by mixing compaction is 5 to 20 times the tap bulk density of fumed silica. Method for manufacturing quartz glass. The method for producing black quartz glass according to any one of claims 8 to 11, wherein the heat sintering time in the air is 0.5 to 5 hours. A product containing a black quartz glass member using the black quartz glass according to any one of claims 1 to 7. The product according to claim 13, wherein the black quartz glass member is an optical component, a light-shielding member, or an infrared heat absorption / heat storage member. The product according to claim 14, wherein the optical component is a spectroscopic cell, a reflector of a projector, or a connector of an optical fiber, and the light-shielding member is a light-shielding member of a semiconductor manufacturing device or an infrared heating device.