Silica glass porous body and method for producing same

Abstract

The present invention relates to a silica glass porous body having a plurality of pores, the pores including open pores, the volume density of the silica glass porous body being 1.1 g / cm3 to 1.7 g / cm3, and the average pore diameter of the open pores as determined by mercury intrusion method being 50 [mu] m to 200 [mu] m.

Description

Technical Field

[0001] This invention relates to porous silica glass and a method for manufacturing porous silica glass. Background Technology

[0002] Because porous silica glass contains multiple pores, it is expected to be used in various applications such as spray plates for supplying source gases in etching processes and chemical vapor deposition processes in semiconductor equipment manufacturing.

[0003] Porous silica glass includes open pores with pores on any one surface. When the open pores include interconnected pores, in addition to the high purity of synthetic silica, the interconnected pores can also possess various properties such as fluid permeability and light transmittance.

[0004] Patent document 1 describes a porous silica glass with a specific average pore size.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2022 / 215662 Summary of the Invention

[0008] The porous silica glass described in Patent Document 1 has room for improvement in terms of fluid permeability and light transmittance.

[0009] The purpose of this invention is to provide a novel porous silica glass with excellent fluid permeability and light transmittance.

[0010] This invention relates to the following porous silica glass.

[0011] A porous silica glass material having multiple pores,

[0012] The vent includes an opening.

[0013] The bulk density of the silica glass porous body is 1.1 g / cm³. 3 ~1.7g / cm 3 ,

[0014] The average pore diameter of the pores determined by mercury porosimetry is 50 μm to 200 μm.

[0015] Furthermore, the present invention relates to a method for manufacturing porous silica glass.

[0016] A method for manufacturing a porous silica glass body with multiple pores, comprising:

[0017] The process of obtaining dense silica glass by heat treatment under pressure of 0.01–200 MPa, inactive gas atmosphere, and temperature of 1200–1700 °C.

[0018] The process of obtaining silica glass foam by foaming heat treatment under pressure of 0-0.4 MPa and temperature of 1300-1800℃, and...

[0019] The process of sintering the above-mentioned silica glass foam under pressure of 0-0.1 MPa and temperature of 1350-1550℃.

[0020] The temperature of the above-mentioned foaming heat treatment is more than 300°C higher than the heat treatment temperature during the manufacture of the above-mentioned silica glass compact.

[0021] According to the present invention, a novel porous silica glass with excellent fluid permeability and light transmittance can be obtained. Attached Figure Description

[0022] Figure 1 It is a perspective view of a component cut into a cuboid shape from any portion of a porous silica glass body according to one embodiment.

[0023] Figure 2 yes Figure 1 The cross-sectional view of the X-X' arrow.

[0024] Figure 3 This is a flowchart illustrating a method for manufacturing a porous silica glass body according to one embodiment. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail using the accompanying drawings. In the drawings, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. It should be noted that the scale of the drawings is not limited to the scale shown. Furthermore, in this specification, the "~" indicating a numerical range refers to the numerical values ​​included before and after it, serving as a lower limit and an upper limit. The aforementioned lower limit and upper limit include rounding ranges.

[0026] <Porous silica glass>

[0027] Reference Figure 1 and Figure 2 The structures of the silica glass porous body 1 and the silica glass porous body component 2 of this embodiment will be described.

[0028] Figure 1 This is a perspective view of component 2, which is a portion of a porous silica glass body 1 cut into a cuboid shape. Figure 2 yes Figure 1 The cross-sectional view of the X-X' arrow.

[0029] The silica glass porous body 1 has a silica glass portion 10 and pores 12.

[0030] The silica glass section 10 uses amorphous silicon dioxide (SiO2) as its main component and is transparent.

[0031] The pore 12 includes an open pore 20 and a closed pore 30. An open pore is a pore that is exposed on at least one surface and has an opening. A closed pore is a pore that is not exposed and contains gas inside.

[0032] The porous silica glass component of the present invention can improve fluid permeability and light transmittance by having open pores.

[0033] In porous silica glass, adjacent pores are sometimes interconnected. Non-interconnected pores are generally spherical in shape. Interconnected pores have a generally circular shape formed by their connection. Additionally, sometimes pores extend from one surface of the porous silica glass component to another. Interconnected pores can be either interconnected or non-interconnected. Even interconnected pores can be non-interconnected; furthermore, for example, if a pore is large, even non-interconnected pores can become interconnected.

[0034] Based on the above methods, such as Figure 2 As shown, the open vent 20 is divided into a non-through, non-connecting vent 21, a non-through, connected vent 22, a connected vent 23, and a connected, non-connecting vent (not shown). Additionally, the closed vent 30 is divided into a non-through, non-connecting vent 31 and a non-through, connected vent 32.

[0035] Non-through, non-connecting vent 21 is formed by non-through, non-connecting vents. Non-through, connecting vent 22 is formed by non-through, connecting vents. Through, connecting vent 23 is formed by connecting vents that extend from any one surface of component 2 to another. The through, connecting vent 23 on the surface of component 2 has a generally circular shape formed by their connection.

[0036] It should be noted that, in Figure 2 In this context, interconnected pores are depicted as two-dimensional interconnected structures, but of course, there are also cases of three-dimensional interconnection.

[0037] The vent is preferably a connecting vent, and more preferably a through-hole connecting vent, which can improve fluid permeability and light transmittance.

[0038] Next, the characteristics of the silica glass porous body of this embodiment will be described.

[0039] The bulk density of the porous silica glass is 1.1 g / cm³. 3 ~1.7g / cm 3 If the bulk density is within the above range, the strength of the silica glass porous body can be sufficiently obtained, and it can fully contain pores.

[0040] The preferred bulk density is 1.2 g / cm³. 3 The above, more preferably 1.3 g / cm³ 3 In addition, the preferred value is 1.6 g / cm³. 3 The following is more preferably 1.5 g / cm³ 3 the following.

[0041] The average pore diameter of the openings is 50 μm to 200 μm. With an average pore diameter of 50 μm or more, both non-through-connected and through-connected pores are easily formed within the openings, and through-connected pores are also easily formed, thus improving fluid permeability and light transmittance. Furthermore, even when a protective film is applied to the surface of a component made from a porous silica glass, scratches on items held in contact with the component can be prevented while maintaining fluid permeability and light transmittance without sealing the openings. Conversely, with an average pore diameter of 200 μm or less, the distribution of fluid permeability and light transmittance caused by pore diameter deviations on the surface of the porous silica glass is reduced. Additionally, stress concentration at specific locations in the silica glass, which could lead to damage, can be suppressed, thus improving mechanical strength.

[0042] As described above, the porous silica glass of this embodiment has a high bulk density and sufficiently high mechanical strength. However, a high bulk density generally tends to result in closed pores or small pore sizes during sintering. Furthermore, if the pore size is increased to improve fluid permeability, the bulk density tends to decrease, making it difficult to achieve the desired mechanical strength. The porous silica glass of this embodiment, using the manufacturing method described later, achieves both high bulk density and a relatively high average pore size by controlling the pressure, temperature, and time during high-temperature heat treatment, foaming heat treatment, and sintering heat treatment.

[0043] The average pore diameter of the above-mentioned vent is preferably 70 μm or more, more preferably 100 μm or more, and preferably 170 μm or less, more preferably 130 μm or less.

[0044] It should be noted that the average pore diameter of the open pores was determined by mercury intrusion porosimetry.

[0045] In a porous silica glass body, the ratio of the total volume of open pores to the total volume of pores (hereinafter also referred to as the "open pore ratio") is preferably 80% or more. If the open pore ratio is 80% or more, the proportion of the aforementioned through-holes 23 formed by the through-holes can be increased. Since the through-holes 23 readily transmit liquids, gases, and light, a higher proportion improves the fluid permeability of the porous silica glass body, which is preferable. The open pore ratio is more preferably 85% or more.

[0046] The total volume of pores is calculated by subtracting the volume of the silica glass portion, derived from the sample weight, from the apparent volume of the sample. Alternatively, X-ray CT can be used to determine the volume of the pores.

[0047] The total volume of the vents was determined by mercury intrusion porosimetry.

[0048] The gas permeability coefficient of the silica glass porous body is preferably 0.2–15 μm. 2 If the gas permeability coefficient is within the above range, sufficient fluid permeability is obtained.

[0049] The gas permeability coefficient is more preferably 0.5 μm. 2 The above is further preferred to be 1.0 μm. 2 The above, and more preferably 10μm. 2 Hereinafter, 5μm is further preferred. 2 the following.

[0050] It should be noted that the gas permeability coefficient of the silica glass porous body is determined using a Perm porosimeter.

[0051] When the thickness is 1.5 mm, the total light transmittance of the porous silica glass is preferably 30% to 60%. If the total light transmittance is within the above range, the loss caused by reflection is small and the transmitted light can be utilized efficiently, and the transmitted light can be uniformly irradiated through the diffusion of the transmitted light.

[0052] The aforementioned total light transmittance is more preferably 35% or more, even more preferably 40% or more, and even more preferably 55% or less, and even more preferably 50% or less.

[0053] It should be noted that the total light transmittance of the silica glass porous body is determined using a spectrophotometer, and the average transmittance of light with wavelengths from 400 nm to 800 nm is taken as the total light transmittance in this specification.

[0054] The silica glass portion of the porous silica glass body is mainly composed of amorphous silicon dioxide (SiO2), with a density of approximately 2.2 g / cm³. 3It should be noted that, in addition to SiO2, the silica glass component may contain different elements to control its properties.

[0055] Examples of elements that can be contained in the silica glass section include lithium (Li), sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), titanium (Ti), cobalt (Co), zinc (Zn), silver (Ag), cadmium (Cd), and lead (Pb). The content of each metallic impurity is 0.5 ppm by mass or less, preferably 0.1 ppm by mass or less. If the content of each metallic impurity is 0.5 ppm by mass or less, it is preferable to use it as a component for semiconductor manufacturing apparatus. It should be noted that in this specification, ppm represents parts per million, and ppb represents parts per billion.

[0056] <Manufacturing Method>

[0057] Next, refer to Figure 3 The method for manufacturing the porous silica glass body of this embodiment will be described.

[0058] In this embodiment, the VAD (Vapor-phase Axial Deposition) method is used as the synthesis method for silica glass. However, within the scope of achieving the effects of the present invention, it is acceptable to appropriately modify the manufacturing method.

[0059] like Figure 3 As shown, the preferred method for manufacturing porous silica glass includes steps S31 to S35.

[0060] In step S31, the raw materials for synthesizing silica glass are selected. There are no particular restrictions on the raw materials for synthesizing silica glass, as long as they are silicon-containing materials that can be gasified. Representative examples include halogen-containing silicon compounds such as silicon chlorides (e.g., SiCl4, SiHCl3, SiH2Cl2, SiCH3Cl3) and silicon fluorides (e.g., SiF4, SiHF3, SiH2F2), or RnSi(OR). 4－n (R: alkyl group with 1 to 4 carbon atoms, n: integer from 0 to 3) alkoxysilanes, halogen-free silicon compounds such as (CH3)3Si-O-Si(CH3)3.

[0061] Next, in step S32, the above-mentioned synthetic raw materials are preferably subjected to flame hydrolysis at a temperature of 1000°C to 1500°C to generate silica particles, which are then blown onto a rotating substrate to accumulate, thereby obtaining an ash body. In the ash body, the silica particles are partially sintered together.

[0062] Furthermore, although not illustrated, for the purpose of controlling electrical properties, the above-mentioned ash material can be dehydrated and the OH group concentration reduced by heat treatment under a vacuum atmosphere. In this case, the heat treatment temperature is preferably 1000℃ to 1300℃, and the treatment time is preferably 1 hour to 240 hours.

[0063] Next, in step S33, the aforementioned ash material is heat-treated under high temperature and high pressure conditions in an inactive gas atmosphere, thereby densifying the silica particles in the ash material by sintering them together, resulting in a dense silica glass body. The dense silica glass body is either a transparent silica glass that is practically free of pores or an opaque silica glass that contains minute pores. In this case, the temperature during the aforementioned high temperature and high pressure heat treatment is preferably 1200°C to 1700°C, the pressure is preferably 0.01 MPa to 200 MPa, and the treatment time is preferably 1 hour to 100 hours.

[0064] In step S33, the aforementioned inert gas dissolves in the silica glass. Representative inert gases include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), nitrogen (N2), or mixtures containing at least two of these, as detailed later, but Ar is preferred. Generally, the solubility of the inert gas relative to silica glass tends to decrease as the partial pressure of the inert gas in the atmosphere or the temperature of the silica glass increases.

[0065] Next, in step S34, the aforementioned dense silica glass body is subjected to a foaming heat treatment. In this process, the inert gas dissolved in the silica glass becomes supersaturated. As bubbles of this inert gas precipitate within the silica glass, they expand due to thermal expansion, resulting in a decrease in bulk density and the formation of a porous silica glass foam. The foaming heat treatment temperature is 1300°C to 1800°C, the pressure is 0 to 0.4 MPa, and the treatment time is preferably 1 minute to 50 hours.

[0066] Here, the foaming mechanism is explained. As mentioned above, the lower the partial pressure of the inert gas in the atmosphere or the higher the temperature of the silica glass, the more likely the solubility of the inert gas relative to the silica glass will decrease. Therefore, in step S34, by processing at a lower pressure or a higher temperature than in step S33, the amount of inert gas dissolved may sometimes become supersaturated, at which point foaming occurs in the silica glass. Furthermore, during the densification heat treatment, the inert gas trapped in the pores expands thermally due to the heat treatment. If the pressure inside the pores increases to a level higher than the pressure of the heat treatment atmosphere, the silica glass, whose viscosity has decreased through heat treatment, will deform, resulting in foaming.

[0067] Considering the above mechanism, even if the temperature during the foaming heat treatment in step S34 is lower than the temperature during the heat treatment in step S33, foaming can still occur. However, since the temperature is higher than the temperature during the heat treatment in step S33, it promotes foaming, so it is preferred that the temperature during the foaming heat treatment is more than 300°C higher than the temperature during the heat treatment.

[0068] In addition, the pressure during the foaming heat treatment in step S34 is preferably lower than the pressure during the heat treatment in step S33, more preferably 0.1 MPa or more lower.

[0069] It should be noted that among the above-mentioned inert gas options, Ar is relatively inexpensive and is preferred from the viewpoint that its solubility in silica glass is highly temperature-dependent and that porosity is easily controlled.

[0070] Next, the silica glass foam is subjected to sintering heat treatment in step S35. Through this process, the pores expand and become interconnected, further connecting with the surface and thus achieving open pore formation. If heat treatment continues in the open pore state, sintering progresses, and the bulk density gradually increases while maintaining the open pore state, resulting in a silica glass porous body with both high bulk density and large open pore size. The heat treatment temperature is preferably 1350°C to 1550°C, the pressure is preferably 0 to 0.1 MPa, and the treatment time is preferably 1 minute to 30 hours. It should be noted that if the treatment time is less than 30 hours, pore closure due to overheating is avoided, which is preferable. Furthermore, from the viewpoint of preventing pore closure caused by overheating, the temperature during sintering heat treatment is preferably lower than that during foaming heat treatment, more preferably at least 200°C lower. Moreover, from the viewpoint of preventing the formation of closed pores due to the sealing of the atmosphere gas during sintering, it is more preferable to perform the sintering heat treatment under vacuum.

[0071] By appropriately adjusting the temperature, pressure, and processing time of the high-temperature and high-pressure heat treatment in step S33, the foaming heat treatment in step S34, and the sintering heat treatment in step S35, the amount of foaming and the degree of pore expansion can be varied, thereby controlling the number of pores, pore size, and bulk density in the porous silica glass. For example, further increasing the temperature in the foaming heat treatment in step 34 can lead to a decrease in the viscosity of the silica glass, making it easier to deform and increasing the pore size. Furthermore, the longer the heat treatment time, the more the pores collide due to convection during foaming, causing the pore walls to break and fuse, thus increasing the pore size. It should be noted that if a higher temperature or longer heat treatment time is used in the sintering heat treatment in step S35, sintering progresses further, resulting in a porous silica glass with a higher bulk density.

[0072] <Fluid-permeable components>

[0073] The porous silica glass of this embodiment exhibits excellent permeability to liquids, gases, and other fluids. Therefore, the porous silica glass of this embodiment, or a silica glass substrate composed of a porous silica glass, is useful in various applications, such as as a fluid-permeable component. For example, the fluid-permeable component of this embodiment can be used as a spray plate component for supplying source gas in etching processes and chemical vapor deposition processes in semiconductor manufacturing.

[0074] <Transparent Components>

[0075] The porous silica glass of this embodiment exhibits excellent light transmittance, making it useful as a light-transmitting component. This light-transmitting component can be used, for example, as a stage component in a semiconductor manufacturing apparatus. In semiconductor manufacturing, inspections are performed at each stage to ensure the reliability of semiconductor wafers. For example, methods are known to irradiate the wafer to be inspected with light, process the captured image, and detect defects; a light-transmitting material is used as a stage component for holding the wafer. Preferably, the light-transmitting material allows light irradiated onto the wafer to pass through while diffusing it. Therefore, if the porous silica glass of this embodiment is used, the total light transmittance at a thickness of 1.5 mm is preferably 30-60%, making it useful as a stage component in a semiconductor manufacturing apparatus.

[0076] When the porous silica glass body of this embodiment is used as a fluid-permeable component or a light-transmitting component, from the viewpoint of protecting the component surface and improving durability, the component can have a protective film on at least one main surface. That is, the present invention relates to a fluid-permeable component with a protective film, which includes a fluid-permeable component made of the porous silica glass body of this embodiment and a protective film formed on at least one main surface of the fluid-permeable component. Furthermore, the present invention relates to a light-transmitting component with a protective film, which includes a light-transmitting component made of the porous silica glass body of this embodiment and a protective film formed on at least one main surface of the light-transmitting component.

[0077] As a method for forming a protective film, known methods described in International Publication No. 2016 / 051921, etc., are preferred, and fluororesin coating is a preferred method. For example, a powder or dispersion of fluororesin is coated onto the surface of a porous silica glass body and sintered at a temperature preferably 280–380°C for 0.1–2 hours, thereby forming a protective film composed of a fluororesin layer. As the fluororesin, at least one selected from PTFE (Poly Tetra Fluoro Ethylene), PFA (Tetra Fluoro Ethylene-Perfluoro Alkylvinyl Ether Copolymer), and FEP (Fluorinated Ethylene Propylene Copolymer) or copolymers containing their basic structures can be used.

[0078] Furthermore, from the viewpoint of maintaining the fluid permeability and light transmittance of the silica glass porous body, the fluororesin is preferably in particulate form. More preferably, the particle size of the fluororesin is larger than the average pore size of the open pores in the silica glass porous body. This prevents the fluororesin particles from penetrating into the pores of the silica glass porous body, thus easily maintaining the fluid permeability and light transmittance of the silica glass porous body.

[0079] From the viewpoint of maintaining light transmittance and fluid permeability and preventing scratches on the wafer caused by friction on the wafer mounted on the silica glass component, the thickness of the protective film is preferably 10 to 200 μm, more preferably 10 to 100 μm, particularly preferably 10 to 50 μm, and most preferably 10 to 30 μm.

[0080] Based on the above, this specification discloses the following porous silica glass and its manufacturing method.

[0081] [1] A porous silica glass having multiple pores,

[0082] The aforementioned pores include open pores.

[0083] The bulk density of the above-mentioned porous silica glass is 1.1 g / cm³. 3 ~1.7g / cm 3 The average pore diameter of the above-mentioned pores, determined by mercury porosimetry, is 50 μm to 200 μm.

[0084] [2] The silica glass porous body according to [1], wherein the pores include interconnecting pores.

[0085] [3] The silica glass porous body according to [1] or [2], wherein the total volume of the above-mentioned open pores is 80% or more relative to the total volume of the above-mentioned pores.

[0086] [4] A porous silica glass according to any one of [1] to [3], wherein the gas permeability coefficient is 0.2 to 15 μm. 2 .

[0087] [5] A porous silica glass according to any one of [1] to [4], wherein the total light transmittance at a thickness of 1.5 mm is 30 to 60%.

[0088] [6] A light-transmitting component, comprising a porous silica glass body as described in any one of [1] to [5].

[0089] [7] A light-transmitting component with a protective film, comprising: a light-transmitting component made of a porous silica glass body as described in any one of [1] to [5], and

[0090] A protective film with a thickness of 10 to 200 μm is formed on at least one main surface of the aforementioned light-transmitting component.

[0091] [8] A stage component for a semiconductor manufacturing apparatus, comprising the light-transmitting component described in [6]. [9] A stage component for a semiconductor manufacturing apparatus, comprising the light-transmitting component with a protective film described in [7].

[0092]

[10] A method for manufacturing a porous silica glass body with multiple pores, comprising:

[0093] Dense silica glass is obtained by heat treatment under pressure of 0.01–200 MPa, inert gas atmosphere, and temperature of 1200–1700 °C.

[0094] Silica glass foam is obtained by foaming heat treatment under pressure conditions of 0–0.4 MPa and temperature of 1300–1800℃.

[0095] The above-mentioned silica glass foam was subjected to sintering heat treatment under a pressure of 0-0.1 MPa and a temperature of 1350-1550℃.

[0096] The temperature of the above-mentioned foaming heat treatment is more than 300°C higher than the heat treatment temperature for manufacturing silica glass compacts.

[0097]

[11] According to the manufacturing method described in

[10] , the temperature of the sintering heat treatment is lower than the temperature of the foaming heat treatment.

[0098]

[12] The manufacturing method according to

[10] or

[11] , wherein the above-mentioned sintering heat treatment is performed under vacuum.

[0099]

[13] The manufacturing method according to any one of

[10] to

[12] , wherein the pores of the aforementioned silica glass porous body include open pores.

[0100] The bulk density of the above-mentioned porous silica glass is 1.1 g / cm³. 3 ~1.7g / cm 3 ,

[0101] The average pore diameter of the above-mentioned pores, determined by mercury porosimetry, is 50 μm to 200 μm.

[0102] Example

[0103] The present invention will be further described in detail below using examples, but the present invention is not to be interpreted in a limited manner by these examples.

[0104] It should be noted that Examples 1 to 6 are exemplary cases, and Examples 7 to 9 are comparative cases.

[0105] Bulk density is calculated by dividing the mass of the sample (measured using an electronic balance) by the apparent volume of the sample, after cutting the object being evaluated into a cylindrical shape with a diameter of 10 mm and a thickness of 5 mm.

[0106] The average pore diameter was determined using mercury porosimetry based on JIS-R1655:2003. Specifically, a cylindrical section with a diameter of 10 mm and a thickness of 5 mm was cut from the object being evaluated. The pore diameter distribution was measured using a mercury porosimeter (Micromeritics: AutoPore V9620). The pore diameter at which the cumulative pore volume was 50% of the total pore volume was taken as the average pore diameter.

[0107] The gas permeability coefficient was determined using a Perm porosimeter. Specifically, a disc-shaped part with a diameter of 25 mm and a thickness of 2 mm was cut from the object being evaluated and placed on the support of the Perm porosimeter (manufactured by PMI: CFP-1200AEXL), and gas was passed through it at a flow rate of 1 to 200 L / min.

[0108] At this point, the gas permeability coefficient (K) at ΔP = 10 kPa is calculated according to the following equation (1). It should be noted that the atmosphere is used as the gas.

[0109] K=(μ·L·Q) / (ΔP·A)…(1)

[0110] In equation (1) above, K is the gas permeability coefficient (unit: m). 2μ is the gas viscosity (in Pa·s), L is the sample thickness (in m), and Q is the gas flow rate (m³ / s). 3 / s), ΔP is the pressure difference between the gas inlet and gas outlet of the sample (unit: Pa), A is the cross-sectional area of ​​the sample (m²). 2 ).

[0111] Total light transmittance was determined using a spectrophotometer. Specifically, a 1.5 mm thick section of the object being evaluated was cut out, and the total light transmittance from wavelengths of 400 nm to 800 nm was measured using a spectrophotometer (Hitachi High-Tech Science: UH4150) and an integrating sphere. The average transmittance at each wavelength was then taken as the measured value.

[0112] (Example 1~Example 8)

[0113] As a raw material for synthesizing silica glass, silicon tetrachloride (SiCl4) is selected and subjected to flame hydrolysis to generate silica particles, which are then blown onto a rotating substrate and deposited to obtain a ash body.

[0114] Next, the ash material was placed in a heating furnace, filled with Ar gas, and subjected to high-temperature and high-pressure treatment at the temperature, pressure, and processing time shown in Table 1 to densify the ash material. Afterward, atmospheric pressure was restored and the material was cooled. The resulting dense silica glass is an opaque silica glass containing tiny pores.

[0115] Next, a foaming heat treatment was performed at the temperature, pressure, and processing time shown in Table 1 to porousen the silica glass compact.

[0116] The porous silica glass foam was further degassed under vacuum and then subjected to sintering heat treatment under reduced pressure at the temperature, pressure and processing time shown in Table 1. After cooling, the resulting porous silica glass was removed.

[0117] (Example 9)

[0118] The gray material obtained in Example 1 was heat-treated at 1250°C for 50 hours to obtain a porous silica glass.

[0119] The silica glass porous body obtained in Example 6 was cut into various evaluation sizes. A dispersion in which PFA resin was dispersed in the coating liquid was coated on one of the main surfaces. The surface was then heat-treated at 320°C for 30 minutes to form a transparent fluoropolymer coating, thereby forming a protective film with a thickness of 30 μm.

[0120] The physical properties of each silica glass porous body obtained based on the above are shown in Table 2.

[0121] Table 1

[0122]

[0123] Table 2

[0124]

[0125] Based on the above results, the bulk density is 1.1 g / cm³. 3 ~1.7g / cm 3 Furthermore, the silica glass porous bodies of Examples 1 to 6, with an average pore diameter of 50 μm to 200 μm, have a high gas permeability coefficient, thus exhibiting good fluid permeability, and a high total light transmittance, thus exhibiting good light transmittance.

[0126] It should be noted that the silica glass porous body of Example 6 has a protective film on its surface. Apart from this, it is manufactured in the same manner as the silica glass porous body of Example 3, but the average pore diameter through the opening is 50 μm to 200 μm, thus showing a gas transmittance coefficient and total light transmittance that are approximately the same as those of Example 3.

[0127] In the silica glass porous bodies of Examples 7 to 9, where the average pore diameter of the open pores is less than 50 μm, the proportion of gas permeability coefficients in Examples 1 to 6 is particularly reduced.

[0128] The present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes or modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2023-041356, filed on March 15, 2023, the contents of which are incorporated herein by reference.

[0129] Industrial availability

[0130] The silica glass porous body of this embodiment has excellent fluid permeability and light transmittance, and is therefore useful, for example, as a stage component of a semiconductor device manufacturing apparatus that requires gas permeability and light transmittance.

[0131] Symbol Explanation

[0132] 1…Porous silica glass

[0133] 2… components

[0134] 10…Silica glass section

[0135] 12… stomata

[0136] 20…OpenPore

[0137] 21…Non-through, non-connecting pores

[0138] 22…Non-through connecting pores

[0139] 23… Through-connecting vents

[0140] 30…Closed Pore

[0141] 31…Non-through, non-connecting pores

[0142] 32…Non-through connecting vents

Claims

1. A porous silica glass material having multiple pores, The vents include open vents. The bulk density of the silica glass porous body is 1.1 g / cm³. 3 ~1.7g / cm 3 , The average pore diameter of the pores determined by mercury porosimetry is 50 μm to 200 μm.

2. The porous silica glass according to claim 1, wherein, The pores include communicating pores.

3. The porous silica glass according to claim 1, wherein, The ratio of the total volume of the vent to the total volume of the vent is more than 80%.

4. The porous silica glass according to claim 1, wherein, The gas permeability coefficient is 0.2–15 μm. 2 .

5. The porous silica glass according to claim 1, wherein, The total light transmittance is 30-60% when the thickness is 1.5mm.

6. A light-transmitting component, comprising a porous silica glass body as described in any one of claims 1 to 5.

7. A light-transmitting component with a protective film, comprising: A light-transmitting component made of a porous silica glass as described in any one of claims 1 to 5, and A protective film with a thickness of 10 to 200 μm is formed on at least one main surface of the light-transmitting component.

8. A stage component for a semiconductor manufacturing apparatus, comprising the light-transmitting component as described in claim 6.

9. A stage component for a semiconductor manufacturing apparatus, comprising the light-transmitting component with a protective film as described in claim 7.

10. A method for manufacturing a porous silica glass body with multiple pores, comprising: The process of obtaining dense silica glass by heat treatment under pressure of 0.01–200 MPa, inactive gas atmosphere, and 1200–1700 °C. The process of obtaining silica glass foam by foaming heat treatment under pressure of 0-0.4 MPa and temperature of 1300-1800℃, and... The process of sintering the silica glass foam under pressure of 0-0.1 MPa and temperature of 1350-1550℃. The temperature of the foaming heat treatment is more than 300°C higher than the heat treatment temperature during the manufacturing of the silica glass compact.

11. The manufacturing method according to claim 10, wherein, The temperature of the sintering heat treatment is lower than the temperature of the foaming heat treatment.

12. The manufacturing method according to claim 10, wherein, The sintering heat treatment is performed under vacuum.

13. The manufacturing method according to claim 10, wherein, The pores in the silica glass porous body include open pores. The bulk density of the silica glass porous body is 1.1 g / cm³. 3 ~1.7g / cm 3 , The average pore diameter of the pores determined by mercury porosimetry is 50 μm to 200 μm.

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