Black quartz glass and method of making same

Abstract

The present invention relates to a black quartz glass, a manufacturing method of the black quartz glass, and an article including a black quartz glass member using the above black quartz glass, the above black quartz glass containing 0.5 to 10 mass% of Si and 0.1 to 5 mass% of SiO, and the remainder being SiO2, and having an SCE reflectance of 10% or less at a wavelength of 350 to 750 nm, the above manufacturing method including: pressure molding a powder obtained by mixing and densifying 0.5 to 10 mass% of Si powder and 0.1 to 5 mass% of SiO powder in (1) fumed silica, or (2) a mixed powder of fumed silica and synthetic silica powder, or (3) a mixed powder of fumed silica, synthetic silica powder, and spherical silica, and sintering the fumed silica in the atmosphere. The present invention provides a black quartz glass having excellent light shielding properties, not causing contamination in a use process, having sufficient color uniformity even in a large size, and capable of being manufactured in a large size, a method of manufacturing the black quartz glass with excellent productivity even in a large size, and an article manufactured using the above black quartz glass.

Description

TECHNICAL FIELD

[0001] The present application relates to a black quartz glass and a manufacturing method thereof. More specifically, the present application relates to a black quartz glass which can be used in a quartz glass cell for optical analysis, a light shielding member of an infrared heating device, an infrared heat absorbing / accumulating member, and the like, and a manufacturing method of the black quartz glass which is efficiently obtained. The present application also relates to an article made of the black quartz glass of the present application.

[0002] Cross Reference to Related Applications

[0003] This application claims priority to Japanese Patent Application No. 2020-166634 filed on October 1, 2020, and Japanese Patent Application No. 2021-146783 filed on September 9, 2021, the entire disclosures of which are hereby incorporated by reference in its entirety. BACKGROUND

[0004] Quartz glass is used for various purposes such as lighting devices, optical device parts, semiconductor industry parts, physicochemical devices, and the like, by effectively utilizing its good light transmittance from the ultraviolet region to the infrared region, low thermal expansion, and resistance to chemicals. Among them, a black glass in which a trace amount of a transition metal oxide is added to quartz glass is used for a site where local light shielding is required, and is utilized in optical device parts such as a quartz glass cell for optical analysis by being joined to transparent quartz glass by heat pressing or the like. However, in recent years, with the development of miniaturization / thinning of parts, the conventional black glass has caused a problem of insufficient light shielding, and a black quartz glass which has higher light shielding and can be easily joined to transparent quartz glass is required.

[0005] In addition, quartz glass also has high heat resistance, high purity in chemistry, and the like, and is also used in jigs for semiconductor manufacturing and the like. However, in recent years, in the heat treatment process of the semiconductor manufacturing process, heating loss has become a problem, and in the heating process using infrared light, a shielding member which shields the irradiation of infrared light other than the heating target, and an infrared heat absorbing / accumulating member for efficiently heating the heating target are required. Based on this, development of a black quartz glass which effectively shields infrared light, has excellent infrared heat absorbing / accumulating properties, can manufacture a large member, and does not contain metal impurities which cause process contamination is required.

[0006] Conventionally, as a black glass in which silica is a main component, a black glass described below has been known.

[0007] For example, in Patent Literature 1, a manufacturing method of a black quartz glass is proposed in which quartz glass powder and niobium pentachloride are mixed, and after the niobium pentachloride is converted to niobium pentoxide, it is heated to 1800°C or higher to be reduced and melted, thereby achieving it.

[0008] In Patent Document 2, it is proposed that a volatile organosilicon compound capable of becoming a carbon source is subjected to a gas phase reaction with porous silica glass, and then heated and fired at a temperature of 1200°C or higher and 2000°C or lower, thereby manufacturing black quartz glass containing carbon derived from the organosilicon compound.

[0009] In Patent Document 3, it is proposed that after a fused silica powder obtained by powderizing a fused quartz glass and a silicon-containing powder are wet-mixed, the obtained molded body is heated at a sintering temperature of less than the melting temperature of silicon, 1350°C to 1435°C, using a casting method, and dried, thereby manufacturing black quartz glass as a composite material having a matrix of fused silica in which a region in which elemental Si is embedded.

[0010] In Patent Document 4, it is proposed that a colored glass sintered body in which carbon as coloring particles at a volume ratio of 0.1% to 30% is dispersed in a matrix of a glass sintered body.

[0011] Patent Document 1: Japanese Patent Application Publication No. 2014-94864

[0012] Patent Document 2: Japanese Patent Application Publication No. 2013-1628

[0013] Patent Document 3: Japanese Patent Application Publication No. 2020-73440

[0014] Patent Document 4: Japanese Patent Application Publication No. 2003-146676

[0015] The entire contents of Patent Documents 1 to 4 are specifically incorporated herein by reference as a disclosure. SUMMARY

[0016] PROBLEMS TO BE SOLVED BY THE INVENTION

[0017] However, the black quartz glass described in Patent Document 1 has a problem in that the uniformity of color is insufficient when it is upsized, and the manufacturing requires a temperature of 1800°C or higher, and the material of the furnace and the heater need to be high-grade materials, and in addition, a large amount of energy is required for heating, and there are problems in productivity. In addition, contamination can occur in the process of using the contained niobium compound, so there are difficulties in application to the semiconductor manufacturing field.

[0018] The black quartz glass described in Patent Document 2 also has a problem in the uniformity of color, and it is difficult to upsize. A non-oxidizing atmosphere is required at the time of manufacturing, and the structure of the furnace is complicated, and the operation becomes cumbersome, and there are problems in productivity. With regard to upsizing, it is also difficult in the structure of the furnace. In addition, the contained carbon is generated in the process of using it as a particle, and contamination can occur, so there are difficulties in application to the semiconductor manufacturing field.

[0019] The black quartz glass described in Patent Document 3 also has a problem of insufficient color uniformity at the time of upsizing. Moreover, due to the limitations of casting molding, there is a problem with upsizing. In addition, the operations of casting molding and drying are complicated and the manufacturing requires a long time, and on this basis, heating at a temperature of 1350°C or higher is required in sintering, so the material of the furnace and the heater need to be high-grade materials, and at the same time, a large amount of energy is required for heating, so there is a problem in productivity.

[0020] The black quartz glass described in Patent Document 4 also has a problem of insufficient color uniformity at the time of upsizing, and in the case after upsizing, the risk of breakage at the time of sintering of the molded body becomes large, so there is a problem that a large black quartz glass cannot be obtained. In addition to this, carbon is generated in the process of using it as a particle and can cause contamination, so there are difficulties in application to the semiconductor manufacturing field.

[0021] The problem to be solved by the present application is to provide a black quartz glass that has excellent light shielding properties, does not cause contamination in the process of use, has sufficient color uniformity at the time of upsizing, and can produce a large ingot.

[0022] Another problem of the present application is to provide a method of producing a black quartz glass that solves the above problem with excellent productivity even for a large ingot.

[0023] Still another problem of the present application is to provide an optical member such as a light splitting unit, a light shielding member for a semiconductor manufacturing device, a black quartz glass product such as an infrared heat absorbing / heat storing member, and the like, which are produced using the black quartz glass.

[0024] [Technical Solution for Solving the Problem]

[0025] The present inventors have conducted intensive research in order to solve the above problem, and as a result, have found that a black quartz glass that is substantially free from metal impurities other than Si and O and does not cause contamination in the process of use can be obtained in a system in which microparticles of Si and SiO are dispersed in quartz glass at a specific concentration, and that this black quartz glass has excellent light shielding properties, has sufficient color uniformity at the time of upsizing, and can be obtained with good productivity, thereby completing the present application.

[0026] The present application is as described below.

[0027] [1] A black quartz glass,

[0028] is a glass (hereinafter referred to as quartz glass) containing 0.5 to 10 mass% of Si and 0.1 to 5 mass% of SiO, and the remainder being SiO2, in which the SCE reflectance at a wavelength of 350 to 750 nm is 10% or less.

[0029] [2] The black quartz glass according to [1],

[0030] L * a * b * Luminance L of the display system * is 30 or less, chromaticity a * is 3.5 or less in absolute value and b * is 4 or less in absolute value.

[0031] [3] The black quartz glass according to [1] or [2],

[0032] The content of metal impurities other than Si element is 1 ppm or less, respectively.

[0033] [4] The black quartz glass according to any one of [1] to [3], satisfying any one or more of the following (a) to (f) of physical properties,

[0034] (a) The density is 2.15 / cm 3 or more and 2.3 g / cm 3 or less,

[0035] (b) The specific heat at a temperature of 500°C is 1090 J / kg-K or more and 1130 J / kg-K or less,

[0036] (c) The thermal diffusivity at a temperature of 500°C is 7 x 10 -7 m 2 / s or more and 8 x 10 -7 m 2 / s or less,

[0037] (d) The thermal conductivity at a temperature of 500°C is 1.5 W / mK or more and 2.1 W / mK or less,

[0038] (e) The thermal expansion rate in the range of 30°C to 600°C is 2 x 10 -7 / °C or more and 12 x 10 -7 / °C or less,

[0039] (f) The light transmittance in the wavelength range of 200 nm to 3000 nm is 0.5% or less at a thickness of 1 mm.

[0040] [5] The black quartz glass according to any one of [1] to [4],

[0041] At least a part of Si contained in the quartz glass is in a granular form, the diameter of the granular substance is 5 μm to 10 μm in terms of D 50 , D 10 is 1 μm or more, and D 9530 μm or less.

[0042] [6] The black quartz glass according to any one of [1] to [5],

[0043] At least a part of SiO contained in the quartz glass is in a granular form, the diameter of the granular substance is D 50 5 μm to 15 μm, D 10 1 μm or more, and D 90 35 μm or less.

[0044] [7] The black quartz glass according to any one of [1] to [6],

[0045] (a) the part of SiO2 is a sintered body of fumed silica, or

[0046] (b) the part of SiO2 is fumed silica of 30 mass% to 60 mass%, and the remaining part is a sintered body of synthetic silica powder having a particle diameter D 50 60 μm to 100 μm, D 10 40 μm or more, and D 95 180 μm or less, or

[0047] (c) the part of SiO2 is fumed silica of 30 mass% to 60 mass%, D 50 5 μm to 15 μm, D 10 1 μm or more, D 95 70 μm or less, spherical silica of 5 mass% to 25 mass%, and the remaining part is a sintered body of synthetic silica powder having a particle diameter D 50 60 μm to 100 μm, D 10 40 μm or more, and D 95 180 μm or less.

[0048] [8] A manufacturing method of a black quartz glass,

[0049] (1) including: pressure-molding a powder obtained by mixing and densifying 0.5 mass% to 10 mass% of Si powder and 0.1 mass% to 5 mass% of SiO powder in fumed silica, heating the pressure-molded product in the atmosphere at a maximum temperature of 1200°C to 1300°C to sinter the fumed silica, thereby obtaining the black quartz glass according to any one of [1] to [6] or the black quartz glass of (a) of [7]; or

[0050] (2) including: pressure-molding a powder obtained by mixing and densifying 0.5 mass% to 10 mass% of Si powder and 0.1 mass% to 5 mass% of SiO powder in fumed silica of 30 mass% to 60 mass%, and the remaining part being a sintered body of synthetic silica powder having a particle diameter D 50 60 μm to 100 μm, D 10a spherical silica having a particle diameter D 95 a synthetic silica powder having a particle diameter D

[0051] (3) includes: a gas phase silica is 30 mass% ~ 60 mass%, D 50 a spherical silica having a particle diameter D 10 a spherical silica having a particle diameter D 95 a spherical silica having a particle diameter D 50 a spherical silica having a particle diameter D 10 a spherical silica having a particle diameter D 95 a synthetic silica powder having a particle diameter D

[0052] [9] The method for manufacturing a black quartz glass according to [8],

[0053] a gas phase silica satisfies at least any one of a tap density of 0.03 g / cm 3 ~ 0.08 g / cm 3 , a BET specific surface area of 50 m 2 / g ~ 100 m 2 / g, an OH group concentration of 0.5 mass% ~ 1.0 mass%, and a content of metal impurities other than Si of 1 ppm or less.

[0054]

[10] The method for manufacturing a black quartz glass according to [8] or [9],

[0055] a particle diameter D 50 of the Si powder is 5 μm ~ 10 μm, D 10 of the Si powder is 1 μm or more, D 95 of the Si powder is 30 μm or less, and a particle diameter D 50 of the SiO powder is 3 μm ~ 15 μm, D 10 of the SiO powder is 1 μm or more, D 90 of the SiO powder is 35 μm or less.

[0056]

[11] The method for producing a black quartz glass according to any one of [8] to

[10] ,

[0057] The mixing and densification is performed in a manner such that the tap density of the powder obtained by the mixing and densification becomes 5 to 20 times the tap density of the fumed silica.

[0058]

[12] The method for producing a black quartz glass according to any one of [8] to

[11] ,

[0059] The heating and sintering time in the atmosphere is 0.5 to 5 hours.

[0060]

[13] An article,

[0061] The black quartz glass member using the black quartz glass according to any one of [1] to [7].

[0062]

[14] The article according to

[13] ,

[0063] The black quartz glass member is an optical member, a light shielding member, or an infrared heat absorbing / accumulating member.

[0064]

[15] The article according to

[14] ,

[0065] The optical member is a light splitting unit, a mirror 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.

[0066] Effects of the Invention

[0067] According to the present application, a black quartz glass having excellent light shielding property, sufficient uniformity of color at the time of upsizing, good productivity, and no contamination in the process of use is provided. Furthermore, according to the present application, a method for producing the above-mentioned black quartz glass with good productivity using a heating process at a relatively low temperature is provided. In addition, the black quartz glass of the present application is suitable for use in a quartz glass unit for optical analysis, a light shielding member of a semiconductor manufacturing device or an infrared heating device, and an infrared heat absorbing / accumulating member because of its excellent light shielding property. DETAILED DESCRIPTION

[0068] [Black Quartz Glass]

[0069] The black quartz glass of the present application is described.

[0070] The black quartz glass of the present application is a quartz glass containing 0.5 to 10 mass% of Si and 0.1 to 5 mass% of SiO and the remainder being SiO2. At least a part of the Si is a monomer composed of a plurality of Si atoms, and at least a part of the Si exists in the quartz glass as a particulate matter composed of the monomeric Si. The SiO is silicon monoxide, and at least a part of the SiO exists in the quartz glass as a particulate matter composed of the SiO.

[0071] If the Si is less than 0.5 mass% and the SiO is less than 0.1 mass%, the luminance L* becomes large and is not preferable, and the SCE reflectance also becomes large and is not preferable. If the Si exceeds 10 mass% and the SiO exceeds 5 mass%, the sintering of raw materials at the time of production is hindered, which can result in a decrease in the mechanical strength of the quartz glass of the present application as a sintered body. The Si is preferably in the range of 0.5 to 5 mass%, and more preferably in the range of 0.5 to 3 mass%. The SiO is preferably in the range of 0.2 to 2 mass%, and more preferably in the range of 0.3 to 2 mass%, with the remainder being SiO2.

[0072] The black quartz glass of the present application has an SCE reflectance of 10% or less at a wavelength of 350 to 750 nm. The SCE reflectance at a wavelength of 350 to 750 nm is measured in accordance with JIS Z 8722. By making the SCE reflectance 10% or less, excellent light shielding properties are exhibited. From the viewpoint of excellent light shielding properties, the SCE reflectance is preferably low, and is preferably 9% or less, and more preferably 8% or less. The lower limit of the SCE reflectance is not particularly limited, but can be 1%.

[0073] The black quartz glass of the present application preferably has a luminance L * a * b * The luminance L * of the display system is 30 or less. By making the luminance L * 30 or less, not only color unevenness does not occur, but also a sufficient black color which does not transmit light, stray light, or scattering light can be exhibited. In addition, the black quartz glass of the present application preferably has a luminance L * a * b * The absolute value of the chromaticity a * of the display system is 3.5 or less and the absolute value of the chromaticity b * is 4 or less. By making the luminance L * , the chromaticity a * , and the chromaticity b * be in the above ranges, the color tone of the black quartz glass of the present application becomes darker, and becomes a black quartz glass having a low SCE reflectance. The luminance L * is preferably 28 or less, the absolute value of the chromaticity a * is 2.8 or less, and the absolute value of the chromaticity b* The absolute value of 3.7 or less makes the color tone darker and is preferred.

[0074] The black quartz glass of the present application has a content of metal impurities other than Si element of 1 ppm or less, respectively. If the content of metal impurities other than Si element is more than 1 ppm, process contamination can occur in the manufacture of semiconductors and the like. In addition, in the field of optical analysis and the like, adverse effects on precision can occur due to fluorescence generation and the like. The content of metal impurities other than Si element can be analyzed, for example, by atomic absorption spectrometry and the like.

[0075] The black quartz glass of the present application has a density of 2.15 g / cm 3 to 2.3 g / cm 3 . The density is almost the same as the theoretical density of transparent quartz glass to which Si and SiO have been added. The density is preferably in the range of 2.17 g / cm 3 to 2.27 g / cm 3 , and more preferably in the range of 2.18 g / cm 3 to 2.25 g / cm 3 .

[0076] The black quartz glass of the present application has a specific heat at 500°C of 1090 J / kg-K or more and 1130 J / kg-K or less. The specific heat at 500°C can be measured by 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.

[0077] The black quartz glass of the present application has a thermal diffusivity at 500°C of 7 x 10 -7 m 2 / s or more and 8 x 10 -7 m 2 / s or less. The thermal diffusivity at 500°C can be measured by flash method according to JIS R 1611. The thermal diffusivity is preferably in the range of 7.2 x 10 -7 m 2 / s or more and 7.9 x 10 -7 m 2 / s or less, and more preferably in the range of 7.4 x 10 -7 m 2 / s or more and 7.6 x 10 -7 m 2 / s or less.

[0078] The black quartz glass of the present application can have a thermal conductivity of 1.5 W / mK or more and 2.1 W / mK or less at 500°C. The thermal conductivity at 500°C can be calculated by multiplying the density, specific heat, and thermal diffusivity of the sintered body. 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.

[0079] The black quartz glass of the present application can have a thermal expansion rate of 2 x 10 -7 / °C or more and 12 x 10 -7 / °C or less at 30°C to 600°C. The thermal expansion rate at 30°C to 600°C can be measured by a thermomechanical analysis method (TMA method). The thermal expansion rate is preferably in the range of 4 x 10 -7 / °C or more and 11 x 10 -7 / °C or less, and more preferably in the range of 6 x 10 -7 / °C or more and 10 x 10 -7 / °C or less.

[0080] The black quartz glass of the present application 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. By making the light transmittance 0.5% or less, excellent light shielding properties are exhibited. From the viewpoint of excellent light shielding properties, the light transmittance is preferably low, and is preferably 0.4% or less, and more preferably 0.3% or less. The lower limit of the light transmittance is not particularly limited, but can be 0.01%.

[0081] In the black quartz glass of the present application, Si is contained as a particulate matter, and the particle diameter of the Si particulate matter is, for example, 5 to 10 μm in terms of D 50 , 1 μm or more in terms of D 10 , and 30 μm or less in terms of D 95 . In the black quartz glass of the present application, SiO is contained as a particulate matter, and the particle diameter of the SiO particulate matter is, for example, 3 to 15 μm in terms of D 50 , 1 μm or more in terms of D 10 , and 35 μm or less in terms of D 90 . By making the particle diameter of the Si particulate matter 5 μm or more in terms of D 50 , and the particle diameter of the SiO particulate matter 3 μm or more in terms of D 50 , the absolute values of the colorimetric values a * and b * become small, and the color tone becomes darker, which is preferable. By making the particle diameter of the Si particulate matter 10 μm or less in terms of D 50 , and the particle diameter of the SiO particulate matter 15 μm or less in terms of D 50 , the lightness L* and the SCE reflectance becomes a value or less, a black quartz glass having excellent light shielding properties is obtained, and sintering of the raw material silica is easy at the time of production of the black quartz glass, and there is a tendency that a black quartz glass which is a sintered body having excellent mechanical strength can be obtained. If the particle diameter of the Si particulate is 1 μm or more and the particle diameter of the SiO particulate is 1 μm or more, there is a tendency that the absolute values of the chromaticities a 10 and b 10 become small and thus are preferred. If the particle diameter of the Si particulate is 10 μm or less and the particle diameter of the SiO particulate is 15 μm or less, sintering of the raw material silica is favorably performed at the time of production of the black quartz glass, and there is a tendency that a black quartz glass which is a sintered body having excellent mechanical strength can be obtained. * * 50 50

[0082] As described later, the black quartz glass of the present application is produced by using fumed silica as a sintering material. Fumed silica is silica of fine powder obtained by combusting silicon tetrachloride gas or the like in a gas phase. Since fumed silica has a particle diameter as small as 10 nm to 30 nm, the bulk density is very low in general, and it is not suitable for granulation or molding. In general, the density of a sintered body obtained by sintering is small, and it cannot satisfy the quartz glass. However, in the present application, by sintering (1) fumed silica in which Si particulate and SiO particulate are dispersed at a specific concentration, or (2) a mixed powder of fumed silica and synthetic silica powder, or (3) a mixed powder of fumed silica, synthetic silica powder, and spherical silica, surprisingly, a quartz glass having a density almost identical to the theoretical density of a quartz glass to which Si and SiO are added is obtained. Moreover, the obtained quartz glass is a black quartz glass having an SCE reflectance of 10% or less. As described later, the fumed silica used in the raw material is fumed silica having a tap bulk density of 0.03 g / cm 3 to 0.08 g / cm 3 , a BET specific surface area of 50 m 2 / g to 100 m 2 / g, an OH group concentration of 0.5 mass% to 1.0 mass%, and / or a content of metal impurities other than Si element of 1 ppm or less, and this is preferred in view of the fact that a quartz glass having a density almost identical to the theoretical density of a quartz glass to which Si and SiO are added can be obtained, and further, a black quartz glass satisfying characteristics such as SCE reflectance can be produced even with a large ingot.

[0083] <Method for producing black quartz glass>

[0084] ​​​​A manufacturing method of the black quartz glass of the present application will be described.

[0085] The manufacturing method of the black quartz glass of the present application includes: pressure molding a powder obtained by mixing and consolidating 0.5 to 10 mass% of Si powder and 0.1 to 5 mass% of SiO powder in (1) fumed silica, or (2) a mixed powder of fumed silica and synthetic silica powder, or (3) a mixed powder of fumed silica, synthetic silica powder, and spherical silica, and sintering the fumed silica in the atmosphere. The maximum temperature of the heating is in the range of 1200 to 1300°C in the case of (1), and in the range of 1250 to 1320°C in the cases of (2) and (3). According to the manufacturing method, the above-described black quartz glass of the present application can be obtained.

[0086] The synthetic silica powder is a high-purity powder-like silica obtained by hydrolyzing, drying, pulverizing, and firing a chemically refined silicate. The spherical silica powder is a high-purity synthetic fused spherical silica obtained by reacting a silicon tetrachloride gas or the like in the gas phase. By adding the synthetic silica powder or the synthetic silica powder and the spherical silica to the fumed silica, the structure of the sintered body can be made more uniform, and the heating time to the maximum temperature can be shortened.

[0087] In the manufacturing method of the present application, a prescribed amount of Si powder and SiO powder are made to coexist in (1) fumed silica, or (2) fumed silica and synthetic silica powder, or (3) fumed silica, synthetic silica powder, and spherical silica powder, and the Si particles and the SiO particles are uniformly mixed in (1) fumed silica, or (2) fumed silica and synthetic silica powder, or (3) fumed silica, synthetic silica powder, and spherical silica powder in a state substantially free of agglomeration, to a dry powder state. In this mixing, consolidation is performed at the same time as the mixing to obtain a powder for pressure molding. In this specification, the operation of consolidation performed at the same time as the mixing is defined as mixing and consolidation.

[0088] To perform the mixing and consolidation to obtain the powder for pressure molding, it is preferable to use Si powder having a particle diameter D 50 of 5 to 10 μm, a particle diameter D 10 of 1 μm or more, and a particle diameter D 95 of 30 μm or less, in an amount of 0.5 to 10 mass%, and synthetic silica powder having a particle diameter D 50 of 3 to 15 μm, a particle diameter D 10 of 1 μm or more, and a particle diameter D 90SiO powder having a particle size of 35 μm or less is used at a proportion of 0.1 to 5 mass %. In addition, in order to obtain a powder for press molding by mixing and densifying, it is preferable to use a synthetic silica powder having a tap density of 0.03 g / cm 3 to 0.08 g / cm 3 , a BET specific surface area of 50 m 2 / g to 100 m 2 / g, an OH group concentration of 0.5 to 1.0 mass %, and a content of metal impurities other than Si of 1 ppm or less. In addition, it is preferable to use a synthetic silica powder having a particle size of 60 to 100 μm in terms of D 50 , a particle size of 40 μm or more in terms of D 10 , and a particle size of 180 μm or less in terms of D 95 . In addition, it is preferable to use a spherical silica having a particle size of 5 to 15 μm in terms of D 50 , a particle size of 1 μm or more in terms of D 10 , and a particle size of 70 μm or less in terms of D 95 . The use of these fumed silica, synthetic silica powder, and spherical silica is preferable from the viewpoint that a quartz glass having a density almost identical to the theoretical density of a quartz glass to which Si and SiO are added can be obtained.

[0089] In addition, it is preferable to use a synthetic silica powder having a particle size of 60 to 100 μm in terms of D 50 , a particle size of 40 μm or more in terms of D 10 , and a particle size of 180 μm or less in terms of D 95 , and a spherical silica having a particle size of 5 to 15 μm in terms of D 50 , a particle size of 1 μm or more in terms of D 10 , and a particle size of 70 μm or less in terms of D 95 . The use of these synthetic silica powder and spherical silica is preferable from the viewpoint that the structure of the sintered body is made more uniform and the heating time to the maximum temperature during sintering can be shortened. In addition, in the case where the raw material silica is a fumed silica and a synthetic silica powder, the fumed silica is 30 to 60 mass %, and the remaining portion is the synthetic silica powder. This is preferable from the viewpoint that the structure of the sintered body is made more uniform and the heating time to the maximum temperature during sintering is shortened. In addition, in the case where the raw material silica is a fumed silica, a synthetic silica powder, and a spherical silica powder, the fumed silica is 30 to 60 mass %, the spherical silica is 5 to 25 mass %, and the remaining portion is the synthetic silica powder. This is preferable from the viewpoint that the structure of the sintered body is made more uniform and the heating time to the maximum temperature during sintering is shortened.

[0090] Generally, fumed silica is not suitable for sintering. However, by performing pressure molding using the powder obtained by mixing and densifying like this and heating at a maximum temperature of 1200°C to 1320°C in the atmosphere, the density of the sintered body obtained can reach almost the theoretical density, and a black quartz glass having excellent SCE reflectance and the like can be obtained.

[0091] The mixing and densifying is preferably performed in such a manner that the tap density of the powder obtained by the densifying becomes 5 to 20 times the tap density of the fumed silica. By making the tap density of the powder for pressure molding 5 times or more the tap density of the fumed silica, the density of the sintered body has a tendency to increase. If the tap density of the powder for pressure molding is 20 times or less the tap density of the fumed silica, the strength of the shaped body does not decrease. The tap density of the powder for pressure molding is preferably in the range of 6 to 15 times, and more preferably 7 to 10 times, the tap density of the fumed silica. The mixing and densifying can be performed using a general mixing device such as a stirring-type mixer, a ball mill, a shaking mixer, a cross mixer, a V-type mixer, and the like.

[0092] The mixed and densified powder can be formed into a desired shape. As the shaping method, a dry method such as die press molding, cold isostatic pressing, and the like, which are generally used in the shaping of ceramics, can be used. The press pressure is, for example, preferably 10 MPa to 300 MPa. If it is 10 MPa or more, the shaped body does not collapse, and the yield at the time of shaping can be maintained. If it is 300 MPa or less, a large-scale equipment is not necessary, the productivity is good, and the production cost can be suppressed, which is desirable.

[0093] The sintering in the case where the raw material silica is fumed silica is performed in the atmosphere such that the maximum sintering temperature is 1200°C to 1300°C, and preferably 1240°C to 1260°C. More preferably, it is performed at 1240°C to 1250°C. If the sintering temperature exceeds 1300°C, the sintered body has a tendency to have a bright L * If the sintering temperature is less than 1200°C, the sintered body has a tendency to have a density and a bending strength that are not good.

[0094] The sintering in the case where the raw material silica is fumed silica and synthetic silica powder is performed in the atmosphere such that the maximum sintering temperature is 1250°C to 1320°C, and preferably 1280°C to 1310°C. More preferably, it is performed at 1290°C to 1300°C. If the sintering temperature exceeds 1320°C, the sintered body has a tendency to have a bright L * If the sintering temperature is less than 1250°C, the sintered body has a tendency to have a density and a bending strength that are not good.

[0095] The raw material silicon dioxide is sintered in the case of fumed silica, synthetic silica powder, and spherical silica powder, and sintering is performed at a maximum sintering temperature of 1250°C to 1320°C, preferably 1280°C to 1310°C in the atmosphere. More preferably, sintering is performed at 1290°C to 1300°C. If the sintering temperature exceeds 1320°C, the sintered body tends to have a high lightness L * If the sintering temperature is less than 1250°C, the sintered body tends to have a low density and a low bending strength.

[0096] In either of the heating and sintering processes, the sintering time at the maximum temperature in the atmosphere furnace can be set to a range of 0.5 to 5 hours, for example. However, it can be appropriately adjusted in consideration of the physical properties of the sintered body and the like. If the sintering time is short, the density and the bending strength tend to decrease. If the sintering time is excessively long, productivity tends to decrease and production costs tend to increase.

[0097] The ingot of the black quartz glass obtained through the above process is processed by a processing machine such as a band saw, a wire saw, a core drill, and the like used in the manufacture of quartz members, and a product of the black quartz glass can be obtained.

[0098] The black quartz glass thus obtained has no color unevenness and exhibits a sufficient black color in which transmission of light, stray light, and scattering do not occur, and is useful in the entire optical field. In addition, the black quartz glass not only has extremely high light shielding performance but also can be joined to transparent quartz glass, and thus is suitable for the manufacture of an optical analysis unit made of quartz glass.

[0099] The present application includes a product including a black quartz glass member using the above-described black quartz glass of the present application. The black quartz glass of the present application has a thermal expansion rate as small as that of quartz glass and other thermal characteristics equivalent to those of quartz glass when used in an environment at a high temperature and requiring dimensional accuracy. Thus, the black quartz glass member of the present application is useful as, for example, an optical component, a light shielding member, or an infrared heat absorbing / accumulating member. The optical component is, for example, a light splitting unit, a mirror 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, the present application is not intended to be limited to these components.

[0100] The black quartz glass of the present application contains no metal impurities and is particularly suitable for a member of a heat treatment device used in semiconductor manufacturing. For example, in a wafer heat treatment device, by forming a portion other than a surface through which infrared rays for heating are transmitted using the black quartz glass of the present application, heat radiated to the outside of the furnace can be efficiently shielded, and energy efficiency can be improved and the temperature distribution in the furnace can be uniformized.

[0101] Example

[0102] Hereinafter, the present application will be specifically described using examples, but the present application is not limited to the examples.

[0103] The sample properties were measured as follows.

[0104] (1) The density of the sintered body was measured using the Archimedes method.

[0105] (2) The SCE reflectance was measured by processing the sample to a thickness of 7 mm, using a spectrophotometer according to JIS Z 8722. The highest value was recorded in the wavelength region of 360 to 740 nm.

[0106] (3) L * a * b * Luminance L* and chromaticity a * , b * of the display system

[0107] (4) The specific heat was measured by processing the sample to a thickness of 7 mm, using a differential scanning calorimeter (DSC method) at a temperature of 500°C.

[0108] (5) The thermal diffusivity was measured by processing the sample to a thickness of 7 mm, using a flash method according to JIS R1611 at a temperature of 500°C.

[0109] (6) The thermal conductivity was calculated using the following equation at a temperature of 500°C.

[0110] Thermal conductivity = specific heat x thermal diffusivity x density of sintered body

[0111] (7) The thermal expansion rate was measured by processing the sample to a size of 3 x 4 x 20 mm L, using a thermal mechanical analysis method (TMA method) at a temperature of 30 to 600°C.

[0112] (8) The light transmittance was measured by processing the sample to a thickness of 1 mm, using a spectrophotometer in the range of 200 to 3000 nm.

[0113] (Example 1)

[0114] In a fumed silica having a tap density of 0.06 g / cm 3 , a BET specific surface area of 85 m 2 / g, an OH group concentration of 0.7 mass%, and a content of metal impurities other than Si of 1 ppm or less, Si powder having a particle size of D 50 7 μm, D 10 4 μm, and D 95 11 μm was added at 2.0 mass%. 50 ​​Calculated as 10μm, with D 10 Calculated as 5μm, with D 90 SiO powder with a diameter of 20 μm was added at a ratio of 0.5% by mass without solvent and mixed and compacted using a ball mill. The obtained tapped bulk density was 0.45 g / cm³. 3 The powder for pressure molding was press-formed at 90 MPa and sintered at 1250 °C in the atmosphere for 3 hours.

[0115] The density of the obtained black quartz glass is 2.20 g / cm³. 3 SCE reflectance is below 5.3%, L * a * b * The brightness of the display system L * It is 20.6, chromaticity a * It is 1.9, b * The specific heat at 500℃ is -0.6, the thermal diffusivity at 500℃ is 7.5 × 10⁻⁶, and the thermal diffusivity at 500℃ is 1103 J / kg·K. -7 m 2 The thermal conductivity at 500℃ is 1.82 W / mK, and the coefficient of thermal expansion at 30℃~600℃ is 9.4×10⁻⁶. -7 The transmittance is below 0.12% in the range of 200nm to 3000nm at a temperature of / ℃. The obtained black quartz glass has no color unevenness, exhibits a fully black color that does not transmit, scatter, or diffuse light, and is visually uniform, with excellent aesthetics.

[0116] (Example 2)

[0117] At a compacted bulk density of 0.06 g / cm³ 3 BET specific surface area 85m² 2 In fumed silica with a particle size of D, the concentration of OH groups is 0.7% by mass and the content of metallic impurities other than Si is less than 1 ppm. 50 Calculated as 8μm, D 10 3μm, D 95 20 μm Si powder was used at 1.0 wt% with a particle size of D 50 Calculated as 10μm, with D 10 Calculated as 5μm, with D 90 SiO powder with a diameter of 20 μm was added at a ratio of 1.0% by mass without solvent and mixed and compacted using a ball mill. The obtained tapped bulk density was 0.45 g / cm³. 3 The powder for pressure molding was press-formed at 90 MPa and sintered at 1250 °C in the atmosphere for 3 hours.

[0118] The obtained black quartz glass had a density of 2.19 g / cm 3 , an SCE reflectance of 7.6% or less, L * a * b * The display system had a lightness L * of 25.2, a chroma a * of 2.6, a chroma b * of 3.3, a specific heat at 500°C of 1108 J / kg-K, a thermal diffusivity at 500°C of 7.5 x 10 -7 m 2 / s, a thermal conductivity at 500°C of 1.83 W / m-K, a thermal expansion coefficient at 30°C to 600°C of 8.3 x 10 -7 / °C, and a light transmittance of 0.17% or less in the range of 200 nm to 3000 nm. The obtained black quartz glass had no color unevenness and exhibited a sufficient black color that did not transmit light, had no stray light, and had no scattering, was visually confirmed to be uniform, and was excellent in terms of aesthetics.

[0119] (Example 3)

[0120] A silica mixed powder was prepared by mixing 50 mass% of fumed silica having a tap density of 0.06 g / cm 3 , a BET specific surface area of 85 m 2 / g, an OH group concentration of 0.7 mass%, and a content of metal impurities other than Si of 1 ppm or less each, 50 mass% of synthetic silica powder having a particle size D 50 of 80 μm, D 10 of 48 μm, and D 95 of 160 μm, and a content of metal impurities other than Si of 1 ppm or less each, 2.0 mass% of Si powder having a particle size D 50 of 6 μm, D 10 of 4 μm, and D 95 of 10 μm, and 0.5 mass% of SiO powder having a particle size D 50 of 10 μm, D 10 of 5 μm, and D 90 of 20 μm, without using a solvent, and by using a ball mill to mix and compact the mixture. The obtained pressurized molding powder having a tap density of 0.60 g / cm 3 was subjected to press molding at 90 MPa, and sintering at 1300°C for 3 hours in the atmosphere.

[0121] The obtained black quartz glass had a density of 2.20 g / cm 3 , an SCE reflectance of 5.3% or less, L * a* b * Luminance L of the display system * 18.2, chromaticity a * 3.2, b * 2.1, specific heat at 500°C of 1105 J / kg-K, thermal diffusivity at 500°C of 7.5 x 10 -7 m 2 / s, thermal conductivity at 500°C of 1.81 W / mK, thermal expansion coefficient at 30°C to 600°C of 9.0 x 10 -7 / °C, light transmittance of 0.14% or less in the range of 200 nm to 3000 nm. The obtained black quartz glass, having no color unevenness, exhibited a sufficient black color system color in which transmission of light, stray light, and scattering do not occur, was visually confirmed to be uniform, and was excellent in aesthetics.

[0122] (Example 4)

[0123] fumed silica having a tap density of 0.06 g / cm 3 , a BET specific surface area of 85 m 2 / g, an OH group concentration of 0.7 mass%, and a content of metal impurities other than Si of 1 ppm or less was 40 mass%, synthetic silica powder having a particle size D 50 of 80 μm, D 10 of 48 μm, and D 95 of 160 μm and a content of metal impurities other than Si of 1 ppm or less was 42 mass%, spherical silica having a particle size D 50 of 11 μm, D 10 of 3 μm, and D 95 of 52 μm and a content of metal impurities other than Si of 1 ppm or less was 18 mass% of a silica mixed powder, Si powder having a particle size D 50 of 6 μm, D 10 of 3 μm, and D 95 of 13 μm was added at 1.0 mass%, SiO powder having a particle size D 50 of 5 μm, D 10 of 2 μm, and D 90 of 9 μm was added at 0.5 mass%, and the mixture was mixed and densified using a ball mill without using a solvent. The obtained pressure-molding powder having a tap density of 0.79 g / cm 3 was press-formed at 90 MPa, and sintered at 1300°C for 3 hours in the atmosphere.

[0124] The obtained black quartz glass had a density of 2.20 g / cm 3SCE reflectance is below 5.2%, L * a * b * The brightness of the display system L * It is 19.0, chromaticity a * For 2.2, b * The specific heat at 500℃ is 1112 J / kg·K, and the thermal diffusivity at 500℃ is 7.5 × 10⁻⁶. -7 m 2 The thermal conductivity at 500℃ is 1.83 W / mK, and the coefficient of thermal expansion at 30℃~600℃ is 7.6×10⁻⁶. -7 The transmittance is below 0.22% in the range of 200nm to 3000nm at a temperature of / ℃. The obtained black quartz glass has no color unevenness, exhibits a fully black color that does not transmit, scatter, or diffuse light, and is visually uniform, with excellent aesthetics.

[0125] (Comparative Example 1)

[0126] At a compacted bulk density of 0.06 g / cm³ 3 BET specific surface area 85m² 2 In fumed silica with a particle size of D, the concentration of OH groups is 0.7% by mass and the content of metallic impurities other than Si is less than 1 ppm. 50 Calculated as 7μm, D 10 4μm, D 95 Si powder with a thickness of 11 μm was added at a ratio of 0.5% by mass without solvent and mixed and compacted using a ball mill. The powder for pressing was then stamped at 90 MPa and sintered at 1250 °C in atmospheric conditions for 3 hours.

[0127] The obtained black quartz glass has a density as low as 2.09 g / cm³. 3 SCE reflectivity is as high as below 13.0%, L * a * b * The brightness of the display system L * It's also as high as 36.2, with chroma a. * For 1.1, b * The value is -1.7. There is uneven color distribution, which is insufficient to prevent light transmission, stray light, and scattering.

[0128] [Table 1]

[0129]

[0130] [Table 2]

[0131]

[0132] industrial applicability

[0133] The present application is useful in the field relating to black quartz glass. According to the present application, a large black quartz glass ingot having excellent light shielding property can be provided economically and efficiently. The black quartz glass of the present application can be suitably used for a quartz glass cell for optical analysis, a light shielding member of a semiconductor manufacturing apparatus or an infrared ray heating apparatus, an infrared ray heat absorbing / heat storing member.

Claims

1. A black quartz glass, is a glass containing 0.5 to 10 mass% of Si and 0.1 to 5 mass% of SiO, and the remainder being SiO2, wherein, SCE reflectance at a wavelength of 350 nm to 750 nm is 10% or less.

2. The black quartz glass according to claim 1, L * a * b * The brightness of the display system L * For values ​​below 30, chromaticity a * The absolute value is less than 3.5 and b * The absolute value is less than 4.

3. The black quartz glass according to claim 1 or 2, The content of metal impurities other than Si element is 1 ppm or less, respectively.

4. The black quartz glass according to claim 1 or 2, satisfying one or more of the following (a) to (f), (a) density of 2.15 / cm 3 above and 2.3 g / cm 3 below, (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) thermal diffusivity at 500°C of 7 x 10 -7 m 2 / s or more and 8 x 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) a thermal expansion rate in the range of 30°C to 600°C of 2 x 10 -7 / °C or more and 12 x 10 -7 / °C or less, (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. The black quartz glass according to claim 1 or 2, At least a part of Si contained in the black quartz glass is in a granular form, the diameter of the granular substance is D 50 of 5 μm to 10 μm, D 10 is 1 μm or more, and D 95 is 30 μm or less.

6. The black quartz glass according to claim 1 or 2, At least a part of SiO contained in the black quartz glass is in a granular form, the diameter of the granular substance is 5 μm to 15 μm in terms of D 50 , the diameter is 1 μm or more in terms of D 10 , and the diameter is 35 μm or less in terms of D 90 .

7. The black quartz glass according to claim 1 or 2, (a) the portion of Si02 is a sintered body of fumed silica, or (b) the portion of Si02 is fumed silica is 30 mass% to 60 mass%, and the remaining portion is a synthetic silica powder having a particle diameter D 50 is 60 μm to 100 μm, D 10 is 40 μm or more, D 95 is a sintered body of a synthetic silica powder having a particle diameter of 180 μm or less, or (c) the portion of Si02 is fumed silica is 30 mass% to 60 mass%, and the remaining portion is a synthetic silica powder having a particle diameter D 50 is 5 μm to 15 μm, D 10 is 1 μm or more, D 95 is a spheroidal silica having a particle diameter of 70 μm or less is 5 mass% to 25 mass%, and the remaining portion is a synthetic silica powder having a particle diameter D 50 is 60 μm to 100 μm, D 10 is 40 μm or more, D 95 is a sintered body of a synthetic silica powder having a particle diameter of 180 μm or less.

8. A method for producing a black quartz glass, (1) comprises: 0.1 mass% to 5 mass% of SiO powder is added to the fumed silica, and the mixture is subjected to mixed densification to obtain a powder for press molding, the powder for press molding is subjected to press molding, and the press molded product is heated in the atmosphere at a maximum temperature of 1200°C to 1300°C to sinter the fumed silica, thereby obtaining the black quartz glass according to any one of claims 1 to 6 or the black quartz glass of (a) of claim 7; or (2) includes: in the gas phase silica is 30 mass% ~ 60 mass%, the remaining part is the particle size D 50 60 μm ~ 100 μm, D 10 40 μm or more, D 95 180 μm or less of synthetic silica powder, add 0.5 mass% ~ 10 mass% Si powder and 0.1 mass% ~ 5 mass% SiO powder, mixed compaction to obtain a powder for pressure molding, the powder for pressure molding is pressure molded, the pressure molded product is heated in the atmosphere at a maximum temperature of 1250 DEG C ~ 1320 DEG C, sintered, thereby obtaining the black quartz glass of any one of claims 1 ~ 6 or the black quartz glass of (b) of claim 7; or (3) comprising: spherical silica having a particle diameter D 50 of 5 μm to 15 μm, D 10 of 1 μm or more, D 95 of 70 μm or less, 5 to 25 mass% of spherical silica having a particle diameter D 50 of 60 μm to 100 μm, D 10 of 40 μm or more, D 95 of 180 μm or less, 0.5 to 10 mass% of Si powder, and 0.1 to 5 mass% of SiO powder are added to the mixed powder of the synthetic silica powder, mixed and densified to obtain a powder for press molding, the powder for press molding is subjected to press molding, the press-molded product is heated in the atmosphere at a maximum temperature of 1250°C to 1320°C to sinter, thereby obtaining the black quartz glass according to any one of claims 1 to 6 or the black quartz glass of (c) of claim 7.

9. The method for producing a black quartz glass according to claim 8, The gas phase silica satisfies at least one of a tapped bulk density of 0.03 g / cm 3 ~ 0.08 g / cm 3 , a BET specific surface area of 50 m 2 / g ~ 100 m 2 / g, an OH group concentration of 0.5 mass % ~ 1.0 mass %, and a content of metal impurities other than Si of 1 ppm or less.

10. The method for producing a black quartz glass according to claim 8 or 9, The particle size D of the Si powder 50 was 5 μm to 10 μm, D 10 was 1 μm or more, D 95 was 30 μm or less, and the particle size D of the SiO powder 50 was 3 μm to 15 μm, D 10 was 1 μm or more, D 90 was 35 μm or less.

11. The method for producing a black quartz glass according to claim 8 or 9, The mixed densification is performed in such a manner that the tap bulk density of the powder for press molding obtained by the mixed densification becomes 5 to 20 times the tap bulk density of the fumed silica.

12. The method for producing a black quartz glass according to claim 8 or 9, The time for heating and sintering in the atmosphere is 0.5 to 5 hours.

13. An article comprising a black quartz glass member, The black quartz glass member uses the black quartz glass according to any one of claims 1 to 7.

14. The article according to claim 13, The black quartz glass member is an optical member, a light shielding member, or an infrared heat absorbing / accumulating member.

15. The article according to claim 14, The optical member is a light splitting unit, a mirror 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.

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