Perfluoroelastomer molded body and protective member

Abstract

Provided are a perfluoroelastomer molded article and a protective member that have excellent plasma resistance and fitting performance.　This perfluoroelastomer molded article does not contain carbon black and has a Shore A hardness of 25-60. This protective member includes said perfluoroelastomer molded article.

Description

[Technical Field]

[0001] The present invention relates to a perfluoroelastomer molded article and a protective member. [Background technology]

[0002] Adhesives containing urethane compounds and silicone compounds are used as adhesives for components in semiconductor manufacturing equipment. However, these adhesives have low plasma resistance, so there is a need for a component that protects the bonding area from plasma (hereinafter also referred to as a protective component).

[0003] However, the locations where the protective member is to be attached come in a variety of shapes, and therefore the protective member is required to have not only plasma resistance but also appropriate hardness and be easily attached to locations of various shapes, i.e., a member with excellent attachability.

[0004] On the other hand, perfluoroelastomer molded articles are known to have excellent heat resistance, chemical resistance, and plasma resistance (Patent Document 1). Furthermore, Patent Document 2 describes a perfluoroelastomer molded article that is a foam. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5044999 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-174927 Summary of the Invention [Problem to be solved by the invention]

[0006] The perfluoroelastomer molded article described in Patent Document 1 contains carbon black, and therefore has high hardness and is not comfortable to wear. Furthermore, the perfluoroelastomer foam described in Patent Document 2 also contains carbon black, which results in high hardness and insufficient wearability. Furthermore, when a perfluoroelastomer molded article containing carbon black is used in a location in a semiconductor manufacturing device where plasma is generated, there is a possibility that particles will be generated from the perfluoroelastomer molded article.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a perfluoroelastomer molded article that is excellent in plasma resistance and wearability, and a protective member that includes the same. [Means for solving the problem]

[0008] As a result of extensive investigations, the present inventors have found that a perfluoroelastomer molded article that does not contain carbon black and has a Shore A hardness within the required range can satisfy the above-mentioned required performance, and have thus completed the present invention.

[0009] The present invention has the following aspects. [1] A perfluoroelastomer molded article that does not contain carbon black, A perfluoroelastomer molded article having a Shore A hardness of 25 or more and 60 or less. [2] The perfluoroelastomer molded article according to [1], which does not contain silica. [3] The perfluoroelastomer molded article according to [1] or [2], having an Asker C hardness of 45 or more and 80 or less. [4] The perfluoroelastomer molded article according to any one of [1] to [3], which is a foamed article. [5] The perfluoroelastomer molded article according to any one of [1] to [4], obtained from a perfluoroelastomer composition containing a perfluoroelastomer and a crosslinking agent and not containing carbon black. [6] The perfluoroelastomer molded article according to any one of [1] to [5], which is obtained by crosslinking a perfluoroelastomer in a perfluoroelastomer composition containing a perfluoroelastomer, a crosslinking agent, and a foaming agent, and which does not contain carbon black. [7] The perfluoroelastomer molded article according to any one of [1] to [6], which has a mass loss due to plasma irradiation of 10% by mass or less, measured by the following method. Measurement method: After measuring the mass of a 2 mm thick sheet-like perfluoroelastomer molded product, it is irradiated with plasma. The plasma-irradiated perfluoroelastomer is washed with pure water, dried, and then its mass is measured again. [8] The perfluoroelastomer molded article according to any one of [1] to [7], wherein the perfluoroelastomer is a perfluoroelastomer that can be crosslinked with an organic peroxide. [9] The perfluoroelastomer molded article according to [8], wherein the organic peroxide-crosslinkable perfluoroelastomer is an elastomer having a perfluoroalkylene group, an elastomer having a perfluoropolyether group, or an elastomer having both a perfluoroalkylene group and a perfluoropolyether group.

[10] The perfluoroelastomer molded article according to any one of [1] to [9], wherein the perfluoroelastomer is a copolymer having units based on tetrafluoroethylene and units based on perfluoroalkyl vinyl ether.

[11] The perfluoroelastomer molded article according to any one of [1] to

[10] , wherein the content of carbon black having a particle size in the range of 2 nm to 800 nm is 3 parts by mass or less per 100 parts by mass of the perfluoroelastomer.

[12] A protective member comprising the perfluoroelastomer molded article according to any one of [1] to

[11] .

[13] The protective member according to

[12] , wherein the size of the protective member is more than 100% and not more than 250% of the size of the gap in which the protective member is disposed.

[14] A protective member according to

[12] or

[13] , which protects a part of a machine that uses plasma or chemicals and that may generate particles due to exposure to the plasma or chemicals.

[15] The protective member according to any one of

[12] to

[14] , which is a protective member for semiconductor manufacturing equipment. [Effects of the Invention]

[0010] The perfluoroelastomer molded article of the present invention, which does not contain carbon black and has a Shore A hardness of 25 to 60, has excellent plasma resistance and wearability. In addition, a protective member containing the perfluoroelastomer molded article of the present invention has plasma resistance and good wearability. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a Shore A indenter. [Figure 2] Figure 2 is a schematic diagram of an Asker C indenter. [Figure 3] FIG. 3 is a schematic cross-sectional view of a semiconductor manufacturing device. [Figure 4] FIG. 4 is a schematic cross-sectional view of a semiconductor manufacturing device. [Figure 5] FIG. 5 is a schematic diagram showing an embodiment of the protective member of the present invention. [Figure 6] FIG. 6 is an enlarged view of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] In the present invention, a unit in a polymer refers to the smallest structural unit produced by polymerizing a monomer having a carbon-carbon unsaturated bond. The name of a unit based on a monomer is expressed by adding "unit" to the name of the monomer. The same applies when the name of the monomer is an abbreviation.

[0013] The perfluoroelastomer molded article of the present invention does not contain carbon black and has a Shore A hardness of 25 or more and 60 or less. Since the perfluoroelastomer molded article of the present invention does not contain carbon black, it has excellent plasma resistance. Since the perfluoroelastomer molded article of the present invention has a Shore A hardness of 25 or more and 60 or less, it has excellent wearability. In the present invention, carbon black refers to carbon black having a particle size in the range of 2 nm to 800 nm. Furthermore, in the present invention, "not containing carbon black" means that the amount of carbon black having a particle size in the range of 2 nm to 800 nm is 3 parts by mass or less, preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, and most preferably 0 part by mass, per 100 parts by mass of perfluoroelastomer. The particle size of carbon black is the primary particle size value provided by the supplier, and is calculated by a method such as the arithmetic number average particle size observed with an electron microscope.

[0014] <Perfluoroelastomer molded body> The perfluoroelastomer molded article of the present invention is obtained from a perfluoroelastomer composition that contains a perfluoroelastomer and a crosslinking agent but does not contain carbon black. The perfluoroelastomer molded article of the present invention may be one obtained by crosslinking a liquid perfluoroelastomer or one obtained by crosslinking a solid perfluoroelastomer. Furthermore, the perfluoroelastomer molded article of the present invention is more preferably a foamed article. Preferably, the perfluoroelastomer molded article of the present invention is obtained by crosslinking the perfluoroelastomer in a perfluoroelastomer composition containing a perfluoroelastomer, a crosslinking agent, and a foaming agent, but not containing carbon black. More preferably, the perfluoroelastomer molded article of the present invention is obtained by foaming a perfluoroelastomer composition containing a perfluoroelastomer, a crosslinking agent, and a foaming agent, but not containing carbon black, and crosslinking the perfluoroelastomer in the perfluoroelastomer composition.

[0015] <Perfluoroelastomer composition> (perfluoroelastomer) The perfluoroelastomer used in the present invention is not particularly limited, and is preferably a triazine ring-forming perfluoroelastomer, a polyol-crosslinkable perfluoroelastomer, an organic peroxide-crosslinkable perfluoroelastomer, or a fluorine-containing organosiloxane-curable perfluoroelastomer, more preferably an organic peroxide-crosslinkable perfluoroelastomer.

[0016] The organic peroxide-crosslinkable perfluoroelastomer is not particularly limited, and may be any perfluoroelastomer having an organic peroxide-crosslinkable moiety. The organic peroxide-crosslinkable moiety is not particularly limited. Examples of the organic peroxide-crosslinkable moiety include radical-reactive moieties, specifically groups having an unsaturated bond between two carbon atoms such as vinyl groups and allyl groups, groups having an unsaturated bond between a carbon atom and an atom other than a carbon atom such as ketones and imines, and halogen atoms. Among these, halogen atoms are preferred, and iodine atoms and bromine atoms are particularly preferred.

[0017] Examples of the organic peroxide-crosslinkable perfluoroelastomer include elastomers having a perfluoroalkylene group, elastomers having a perfluoropolyether group, elastomers having both a perfluoroalkylene group and a perfluoropolyether group, and silicone elastomers having fluorine atoms, and elastomers having a perfluoroalkylene group are more preferred in terms of their excellent plasma resistance.

[0018] As an elastomer having a perfluoroalkylene group, a copolymer having a unit based on tetrafluoroethylene (hereinafter also referred to as TFE) (hereinafter also referred to as TFE unit) and a unit based on perfluoroalkyl vinyl ether (hereinafter also referred to as PAVE) (hereinafter also referred to as PAVE unit) is preferred in terms of its excellent plasma resistance.

[0019] As the PAVE, one represented by the following formula (1) is preferred. CF2=CF-O-Rf...Equation (1) Here, Rf is a perfluoroalkyl group having 1 to 20 carbon atoms and optionally having an etheric oxygen atom. Rf has 1 to 20 carbon atoms, and more preferably 1 to 8 carbon atoms.

[0020] Among the PAVEs represented by the following formula (1), CF2=CF-O-CF3, CF2=CF-O-CF2CF3, CF2=CF-O-CF2CF2CF3, CF2=CF-O-CF2CF(CF3)OCF2CF2CF3, and CF2=CF-O-CF2CF2-O-CF2CF3 are preferred, with CF2=CF-O-CF3 being more preferred. One or more PAVEs may be used.

[0021] The copolymerization ratio in the copolymer having TFE units and PAVE units is preferably TFE units / PAVE units=30 to 80 / 70 to 20 (molar ratio), which provides excellent rubber physical properties. The copolymer having TFE units and PAVE units may further have units based on a monomer other than TFE and PAVE, if necessary.

[0022] The copolymer having TFE units and PAVE units can be produced, for example, by polymerizing a monomer component containing TFE and PAVE in the presence of a radical polymerization initiator, for example, by the method disclosed in WO 2010 / 082633.

[0023] The perfluoroelastomer used in the present invention is one that is substantially free of hydrogen atoms in order to achieve excellent heat resistance and chemical resistance. "Substantially free of hydrogen atoms" means that the hydrogen atom content in the perfluoroelastomer used in the present invention is 3% by mass or less. The hydrogen atom content in the perfluoroelastomer used in the present invention is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.3% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass.

[0024] In the present invention, a perfluoroelastomer having a hydrogen atom content of more than 0% by mass and not more than 3% by mass can be obtained, for example, by using a chain transfer agent containing a hydrogen atom or a comonomer containing a hydrogen atom.

[0025] Examples of chain transfer agents containing hydrogen atoms include linear or cyclic saturated hydrocarbons such as methane, ethane, propane, butane, pentane, hexane, and cyclohexane; alcohols such as methanol, ethanol, and propanol; and mercaptans such as tert-dodecyl mercaptan, n-dodecyl mercaptan, and n-octadecyl mercaptan. One or more chain transfer agents containing hydrogen atoms can be used. A chain transfer agent containing a hydrogen atom and a chain transfer agent not containing a hydrogen atom may be used in combination.

[0026] Examples of comonomers containing hydrogen atoms include CF2=CF-O-CH2CF3, CF2=CF-O-CH2CF2CF2CF3, CF2=CF-O-CH2(CF2CF2)2H, CF2=CF-O-CF2CF2CH2-I, CF2=CF-O-CF2CF2CH2-Br, CF2=CF-O-CF2CF2(CF3)-O-CF2CF2CH2-I, CF2=CF-O-CF2CF2(CF3)-O-CF2CF2CH2-Br, and CH2=CH-CF2CF2CF2CF2CF2CF2CF2-CH=CH2. One or more types of comonomers containing hydrogen atoms can be used. Comonomers containing hydrogen atoms may also be copolymerized with comonomers that do not contain hydrogen atoms.

[0027] Hereinafter, a preferred embodiment of the present invention will be described taking as an example a case where the perfluoroelastomer molded article is a foam, but the present invention is not limited to the following description. Furthermore, when the protective member described below includes a perfluoroelastomer molded body, which is a foam, it is expected that it will be attached by being pressed with a pointed tool to fit into a gap. Therefore, when evaluating the attachability of the protective member of the present invention, the ease of attachment may be referred to as assemblability hereinafter.

[0028] (Crosslinking agent) The crosslinking agent used in producing the perfluoroelastomer used in the present invention is not particularly limited. Examples of crosslinking agents include organic peroxides and organic polysiloxanes containing hydrosilyl groups in the molecule, and among these, organic peroxides are preferred. Organic peroxides with a one-minute half-life temperature, which is the temperature at which half of the organic peroxide decomposes in one minute, of 150 to 250°C are preferred, and organic peroxides with a one-minute half-life temperature of 150 to 200°C are more preferred. Specific examples include di-tert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, α,α-bis(tert-butylperoxy)-p-diisopropylbenzene, 1,3-bis(tert-butylperoxyisopropyl)benzene, dialkyl peroxides such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroxyperoxide, benzoyl peroxide, tert-butylperoxybenzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butylperoxymaleic acid, and tert-butylperoxyisopropyl carbonate. One or more organic peroxides can be used.

[0029] The content of the organic peroxide is preferably from 0.05 to 10 parts by mass, more preferably from 0.3 to 8 parts by mass, and most preferably from 0.5 to 6.5 parts by mass, relative to 100 parts by mass of the perfluoroelastomer.

[0030] (foaming agent) The perfluoroelastomer composition for obtaining the perfluoroelastomer molded article of the present invention contains a foaming agent. Specific examples of blowing agents include organic chemical blowing agents, inorganic chemical blowing agents, and gas blowing agents. Perfluoroelastomer compositions containing organic chemical blowing agents and inorganic chemical blowing agents begin a foaming reaction when heated to a predetermined temperature or higher. When a gas blowing agent is injected into a perfluoroelastomer composition, the gas blowing agent generates bubbles in the perfluoroelastomer composition.

[0031] The foaming agent is preferably an organic or inorganic chemical foaming agent, and particularly preferably an organic or inorganic chemical foaming agent that reacts at the temperature at which crosslinking or molding is carried out.

[0032] Examples of organic chemical foaming agents include azo compounds, nitroso compounds, and hydrazine compounds, and more specifically, azodicarbonamide, barium azodicarboxylate, N,N-dinitrosopentamethylenetetramine, benzenesulfonylhydrazine, and hydrazodicarbonamide. An example of an inorganic chemical foaming agent is sodium bicarbonate.

[0033] The content of the blowing agent in the perfluoroelastomer composition of the present invention is not particularly limited, but in the case of an organic chemical blowing agent, it is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 15 parts by mass, per 100 parts by mass of the perfluoroelastomer, and in the case of an inorganic chemical blowing agent, it is preferably 0.1 to 2 parts by mass, more preferably 0.1 to 1 part by mass, per 100 parts by mass of the perfluoroelastomer. If the content of the blowing agent is equal to or greater than the lower limit, the foaming reaction is likely to proceed. If the content of the blowing agent is equal to or less than the upper limit, the foam state is likely to be uniform.

[0034] (Crosslinking aid) When a crosslinking aid is used in producing the perfluoroelastomer molded article of the present invention, it is more preferable to use one or more crosslinking aids selected from the group consisting of triallyl cyanurate, triallyl isocyanurate (hereinafter also referred to as TAIC), and trimethallyl isocyanurate. In particular, from the viewpoint of crosslinking reactivity, it is more preferable that the crosslinking aid is TAIC, and it is particularly preferable to use only TAIC as the crosslinking aid.

[0035] When the perfluoroelastomer composition contains a crosslinking aid, the content of the crosslinking aid is preferably 0.4 parts by mass or less, more preferably 0.2 parts by mass or less, and even more preferably 0.1 parts by mass or less, per 100 parts by mass of the perfluoroelastomer. When the content of the crosslinking aid is 0.4 parts by mass or less, the perfluoroelastomer molded article obtained by foaming the perfluoroelastomer composition and crosslinking the perfluoroelastomer contained in the perfluoroelastomer composition has a uniform foaming state and excellent surface smoothness, and is excellent in physical properties such as tensile strength at break, heat resistance, and chemical resistance.

[0036] When a crosslinking aid is used in producing the perfluoroelastomer molded article of the present invention, the lower limit of the content of the crosslinking aid is preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, and most preferably 0.01 part by mass or more, per 100 parts by mass of the perfluoroelastomer. When the crosslinking aid is contained within this range, the perfluoroelastomer molded article has excellent physical properties, as well as excellent heat resistance and chemical resistance.

[0037] It is most preferable that the perfluoroelastomer molded article of the present invention is produced without using a crosslinking aid.

[0038] (Other additives) The perfluoroelastomer composition may contain additives other than the crosslinking agent, foaming agent, and crosslinking aid, provided that the effects of the present invention are not adversely affected. Examples of such additives include fillers, acid acceptors, processing aids, plasticizers, softeners, antioxidants, colorants, pigments, stabilizers, adhesives, release agents, electrical conductivity imparting agents, thermal conductivity imparting agents, surface anti-adhesive agents, tackifiers, flexibility imparting agents, heat resistance improvers, flame retardants, ultraviolet absorbers, oil resistance improvers, scorch inhibitors, lubricants, and antifouling modifiers.

[0039] The content of other additives in the perfluoroelastomer composition is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, per 100 parts by mass of perfluoroelastomer. It is most preferable that no other additives are included. By not including other additives, the condition of a Shore A hardness of 25 to 60 is more easily satisfied, resulting in excellent assembly properties.

[0040] Examples of fillers include silica. The content of silica in the perfluoroelastomer composition is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of perfluoroelastomer. It is most preferable that the perfluoroelastomer composition does not contain silica. In the present invention, "silica" refers to a substance containing 50% or more silicon dioxide, preferably 70% or more, more preferably 90% or more, and most preferably 95% or more silicon dioxide. Furthermore, in the present invention, "silica-free" means that the amount of silica per 100 parts by mass of perfluoroelastomer is 3 parts by mass or less, preferably 1 part by mass or less, more preferably 0.5 parts by mass or less, and most preferably 0 part by mass. A perfluoroelastomer molded article produced from a silica-free perfluoroelastomer composition is likely to satisfy the condition of a Shore A hardness of 25 or more and 60 or less, and has excellent assembly properties.

[0041] Examples of acid acceptors include metal oxides. When the perfluoroelastomer composition contains a metal oxide, the content thereof is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and most preferably 1 part by mass or less, per 100 parts by mass of the perfluoroelastomer. A perfluoroelastomer molded article produced from a perfluoroelastomer composition containing 5 parts by mass or less of a metal oxide has excellent plasma resistance and suppresses particle generation, thereby reducing equipment contamination.

[0042] The perfluoroelastomer molded article of the present invention does not contain carbon black. Since the perfluoroelastomer molded article of the present invention does not contain carbon black, it has excellent plasma resistance and suppresses the generation of particles caused by carbon black, thereby reducing equipment contamination.

[0043] Furthermore, the fact that the perfluoroelastomer molded article of the present invention does not contain carbon black also contributes to meeting the condition of a Shore A hardness of 25 or more and 60 or less, thereby improving the ease of assembly.

[0044] <Method of manufacturing perfluoroelastomer molded article> The perfluoroelastomer molded article, which is the foam of the present invention, is preferably produced by foaming the perfluoroelastomer composition and simultaneously crosslinking the perfluoroelastomer in the perfluoroelastomer composition (hereinafter also referred to as foaming and crosslinking).

[0045] The production of perfluoroelastomer molded articles is preferably carried out by simultaneously molding and foaming and crosslinking so that the desired shape is obtained when the foaming reaction is completed. Although it is possible to further mold the perfluoroelastomer molded article (e.g., a sheet-like molded article) after foaming and crosslinking by cutting it into a desired shape, the method of simultaneously foaming and molding into a desired shape is preferred because it has a good yield. Examples of molding methods include various molding methods such as pressure molding (compression molding), extrusion molding, and injection molding.

[0046] When the perfluoroelastomer composition is heated to a temperature equal to or higher than the decomposition temperature of the blowing agent, a foaming reaction occurs, and when the perfluoroelastomer composition is heated to a temperature equal to or higher than the decomposition temperature of the crosslinking agent, a crosslinking reaction occurs. In the present invention, it is preferable to heat the composition to a temperature equal to or higher than the decomposition temperature of the blowing agent and the decomposition temperature of the crosslinking agent, so that the foaming reaction and the crosslinking reaction occur simultaneously. The heating may be carried out under pressure or under normal pressure.

[0047] The crosslinking temperature of the perfluoroelastomer in the perfluoroelastomer composition is preferably in the range of 100 to 300°C. Heating within this temperature range allows the foaming reaction and crosslinking reaction to proceed in a well-balanced manner, resulting in a perfluoroelastomer molded article with excellent foam uniformity. When molded under pressure, a perfluoroelastomer molded article with excellent surface smoothness is easily obtained. Furthermore, a perfluoroelastomer-containing molded article with excellent physical properties such as tensile strength at break, as well as excellent heat resistance and chemical resistance can be obtained.

[0048] Furthermore, by combining primary heating at a relatively low temperature with secondary heating at a relatively high temperature, the crosslinking reaction proceeds more smoothly, resulting in a perfluoroelastomer molded article with excellent mechanical properties. The primary heating temperature is preferably 100 to 250°C. The secondary heating temperature is higher than the primary heating temperature, and is preferably 150 to 300°C, more preferably 150 to 250°C, and most preferably 170 to 250°C. The secondary heating temperature is preferably at least 10°C higher, more preferably at least 20°C higher than the primary heating temperature. The secondary heating can also be performed by increasing the temperature in stages. The heating time can be selected appropriately.

[0049] A specific example of a combination of primary heating and secondary heating is a method in which primary heating is performed in a heat press at 150 to 200°C for 3 to 60 minutes, crosslinking and molding are performed, and then the resulting molded body is heated in an oven at a temperature higher than the heat press temperature, 170 to 250°C, for 1 to 24 hours to further promote the crosslinking reaction.

[0050] The cells in the perfluoroelastomer molded article of the present invention may be closed cells or open cells. Closed cells are cells that are not connected to the external space of the foam. On the other hand, open cells are cells that are connected to the external space of the foam. In other words, cells whose interiors can be replaced with water when immersed in water are open cells, and cells whose interiors cannot be replaced with water are closed cells. The perfluoroelastomer molded article of the present invention, which is a foamed article, may have a skin layer.

[0051] The expansion ratio of the perfluoroelastomer molded article of the present invention is not particularly limited. The expansion ratio can be adjusted by adjusting molding conditions such as the amount of foaming agent used, molding temperature, and molding time. The expansion ratio is defined as [specific gravity before foaming (specific gravity of the composition)] / [specific gravity after foaming (specific gravity of the perfluoroelastomer molded article)].

[0052] The perfluoroelastomer molded article of the present invention has a Shore A hardness of 25 or more and 60 or less. The Shore A hardness can be measured by the method specified in JIS K 6253. When the Shore A hardness of the perfluoroelastomer molded article of the present invention is within the above range, a protective member having the perfluoroelastomer molded article of the present invention, which will be described later, has excellent assemblability.

[0053] It is desirable that the perfluoroelastomer molded article of the present invention has both bending resistance and a moderate resilience when pressed with a pointed tool. If the bending resistance is sufficient, sealing defects are unlikely to occur even if the number of fitting operations is increased. Furthermore, if the resilience is sufficient, the molded article is unlikely to be destroyed by a pointed tool. The inventors have discovered that a perfluoroelastomer molded article having a Shore A hardness of 25 to 60 satisfies both of these requirements.

[0054] The perfluoroelastomer molded article of the present invention preferably has a Shore A hardness of 25 to 60 and an Asker C hardness of 45 to 80, more preferably a Shore A hardness of 28 to 50 and an Asker C hardness of 50 to 75, and most preferably a Shore A hardness of 30 to 45 and an Asker C hardness of 55 to 70. The Asker C hardness can be measured by the method specified in JIS K 6253.

[0055] The reason why the perfluoroelastomer of the present invention preferably has a Shore A hardness of 25 or more and 60 or less and an Asker C hardness of 45 or more and 80 or less will be explained with reference to the drawings.

[0056] Fig. 1 is a schematic diagram of a Shore A indenter. Fig. 2 is a schematic diagram of an Asker C indenter. The indenter used to measure Shore A hardness has a flat tip, while the indenter used to measure Asker C hardness is hemispherical; the shapes of the indenters used to measure Shore A hardness and Asker C hardness are different. The inventors have found that if the hardnesses measured with indenters of different shapes are within their respective preferred ranges, the bending resistance and resilience will be superior.

[0057] <Protective materials> The protective member of the present invention includes the perfluoroelastomer molded article of the present invention described above. The protective member of the present invention may be formed solely from the perfluoroelastomer molded article of the present invention, or may be a composite with other members.

[0058] The protective member of the present invention is preferably used to protect a part (hereinafter also referred to as a particle generation source) that may generate particles due to exposure to plasma or chemicals in a machine (hereinafter also referred to as a machine) that uses plasma or chemicals. Examples of particle generation sources include an adhesive layer containing an adhesive and an impact absorbing layer made of an impact absorbing material, and examples of adhesives and impact absorbing materials include urethane-based compounds and silicon-based compounds.

[0059] Examples of the machine include, but are not limited to, an etching apparatus, a cleaning apparatus, an exposure apparatus, a polishing apparatus, a film forming apparatus, a liquid processing apparatus, and an analytical instrument. A specific example of the machine is a semiconductor manufacturing apparatus.

[0060] The protective member is suitable for use in protecting particle sources present in gaps within a machine. Gaps within a machine are generated between components that constitute the machine.

[0061] The embodiments of the present invention will be described with reference to the drawings, which do not limit the scope of the present invention. Fig. 3 is a schematic cross-sectional view of a semiconductor manufacturing apparatus. Fig. 4 is a schematic cross-sectional view of a semiconductor manufacturing apparatus. Fig. 5 is a schematic view showing an embodiment of a protective member of the present invention. Fig. 6 is an enlarged view of Fig. 5.

[0062] 3. The vacuum chamber of the semiconductor manufacturing equipment includes a ceramic electrostatic chuck 1, an adhesive layer 2, a cooling plate 3, a silicon wafer 4, a wall 5 of the vacuum chamber (hereinafter also referred to as the wall 5), a top plate 6, and a plasma generation mechanism 7.

[0063] The ceramic electrostatic chuck 1 is bonded to the upper surface of the cooling plate 3 via an adhesive layer 2. The ceramic electrostatic chuck 1 is primarily composed of alumina, but the material is not limited thereto. The material of the adhesive layer 2 is a urethane-based compound. The material of the adhesive layer is not particularly limited, but as mentioned above, other examples include silicon-based compounds. The cooling plate 3 is a rectangular plate-like member in a plan view, and is primarily composed of aluminum, but the material is not limited thereto. The cooling plate may be equipped with a temperature sensor inside.

[0064] A silicon wafer 4 is placed on the upper surface of the ceramic electrostatic chuck 1. The silicon wafer is mainly composed of silicon. The wall 5 stands upright from the edge of the cooling plate 3 and is disposed so as to surround the ceramic electrostatic chuck 1, the adhesive layer 2, and the silicon wafer 4. The wall 5 is mainly made of aluminum, but the material is not limited thereto.

[0065] The cooling plate 3 is a rectangular plate-like member in a plan view, and a top plate 6 is arranged to cover the space surrounded by the cooling plate 3 and the wall 5. The top plate 6 is mainly made of aluminum, but the material is not limited thereto. A plasma generation mechanism 7 is disposed on the underside of the top plate 6. The plasma generation mechanism 7 is fixed to the top plate 6 with screws, but the fixing method is not limited thereto. The cooling plate 3 and the wall 5, and the wall 5 and the top plate 6 are in contact with each other, and form a vacuum chamber inside the vacuum chamber.

[0066] 4 will be described below. The adhesive layer 2 is divided into an adhesive layer 21 that contributes to bonding the ceramic electrostatic chuck 1 to the cooling plate 3, and an adhesive layer 22 that does not contribute to bonding the ceramic electrostatic chuck 1 to the cooling plate 3. One surface of the adhesive layer 22 is in contact with the cooling plate 3, but the surface of the adhesive layer 22 opposite to the surface in contact with the cooling plate 3 is not in contact with the ceramic electrostatic chuck 1 and is exposed to the space inside the vacuum chamber. When the adhesive layer 22 is irradiated with plasma generated from the plasma generation mechanism 7, particles may be generated in the adhesive layer.

[0067] 5 and 6 will be described below. The adhesive layer 22 is a source of particle generation and needs to be protected. Therefore, a protective member 8 is disposed in the vacuum chamber to protect the adhesive layer 22 and prevent the adhesive layer 22 from being exposed to plasma.

[0068] The protective member 8 consists solely of the perfluoroelastomer molded article of the present invention. However, the protective member of the present invention may consist solely of the perfluoroelastomer molded article of the present invention, or may be a composite with other members.

[0069] Protective member 8 is disposed in a gap formed between ceramic electrostatic chuck 1 and wall 5. However, the position at which the protective member of the present invention is disposed is not particularly limited as long as it is between a particle generation source and a plasma irradiation source or a chemical solution supply source, or between the particle generation source and a place where plasma, chemical solution, etc. may be reflected.

[0070] The ceramic electrostatic chuck 1 and the wall 5, which form the gap in which the protective member 8 is disposed, are disposed in parallel with each other and spaced apart by 15 mm. However, the shape of the gap in which the protective member of the present invention is disposed is not particularly limited.

[0071] The protective member 8 is plate-shaped and has a thickness of 20 mm and a height of 30 mm. The 20 mm-thick protective member 8 is disposed in a 15 mm gap formed between the ceramic electrostatic chuck 1 and the wall 5. However, the shape of the protective member of the present invention can be appropriately designed depending on the location where the protective member is disposed. For example, the protective member of the present invention may be a ring-shaped protective member in addition to a plate-shaped protective member.

[0072] Furthermore, the size (thickness) of the protective member of the present invention is not particularly limited as long as it can cover the particle generation source. The size (thickness) of the protective member of the present invention is preferably more than 100% but not more than 250% of the size of the gap in which the protective member is disposed, and more preferably 105% or more but not more than 200%. By making the size (thickness) of the protective member more than 100% but not more than 250% of the size of the gap in which the protective member is disposed, the gap can be filled with the protective member 8 without impairing assembly ease. For example, when the protective member is disposed in a gap of 5 mm, the thickness of the protective member can be set to 5.3 mm to 7 mm.

[0073] The protective member 8 is in contact with the adhesive layer 22. However, the protective member of the present invention may or may not be in contact with the particle generating source.

[0074] When the protective member is, for example, a laminate of the perfluoroelastomer molded article of the present invention and a member other than the perfluoroelastomer molded article of the present invention, it is preferable to orient the surface of the perfluoroelastomer molded article of the present invention toward the plasma irradiation source, the chemical solution supply source, etc., or a location where the plasma, chemical solution, etc. may be reflected, in order to prevent the generation of particles.

[0075] As described above, it is assumed that the protective member of the present invention is attached by pushing it with a jig with a fine tip and fitting it into a gap. Protective member 8 is attached by pushing it with a needle-shaped jig with a 3 mm diameter ball at the tip, but the jig used to attach the protective member of the present invention is not particularly limited.

[0076] In the vacuum chamber, only one protective member of the present invention may be used, or two or more protective members may be used. Furthermore, only one protective member of the present invention may be used in one gap where the protective member can be disposed, or two or more protective members may be used.

[0077] The protective member of the present invention contains the perfluoroelastomer molded article of the present invention, and therefore has excellent plasma resistance and wearability. By protecting a particle generation source with the protective member of the present invention, it is possible to suppress particle generation from the particle generation source in a vacuum chamber of a semiconductor manufacturing device. [Example]

[0078] The present invention will be described in detail below with reference to examples, but is not limited to these examples. Examples 1, 2, and 3 are working examples, and Examples 4 and 5 are comparative examples. The following measurement and evaluation methods were used.

[0079] [Hardness measurement] The Shore A hardness of a 6 mm thick sheet-like perfluoroelastomer molded product was measured in accordance with JIS K 6253. Also, the Asker C hardness was measured in accordance with JIS K 7312.

[0080] [Wearability] A stainless steel plate (2 mm thick, 50 mm high, 50 mm deep) was placed parallel to the plate, leaving a 5 mm gap. The ease of fitting a perfluoroelastomer (6 mm thick, 30 mm high, 30 mm deep) into the gap was evaluated. The evaluation shown in Table 1 was based on the following criteria: (Evaluation criteria) 〇···Easy to put on. ×...Difficult to put on.

[0081] [Plasma resistance] The mass of a 2 mm thick sheet-like perfluoroelastomer molded article was measured and then irradiated with plasma. The plasma-irradiated perfluoroelastomer was washed with pure water, dried, and then its mass was measured again. The evaluations shown in Table 1 were based on the following criteria: (Evaluation criteria) 〇 Mass loss due to plasma exposure is 10% or less by mass. × Mass loss due to plasma irradiation is greater than 10% by mass.

[0082] The components shown in Table 1 are as follows: Perfluoroelastomer: TFE / PMVE=66:34 The polymerization was carried out according to the description in WO 2010 / 082633. TFE-P copolymer: AGC, AFLAS FEPM series 150P, hydrogen atoms 4% by mass Carbon black: Ashland MT-Carbon United N990 Crosslinking agent: Mitsubishi Chemical triallyl isocyanurate (TAIC) Crosslinking agent: Perkadox 14 (a mixture of 40% by mass of 1,3-bis(tert-butylperoxyisopropyl)benzene and 60% by mass of calcium carbonate), manufactured by Kayaku Akzo Co., Ltd. Foaming agent composition: VP#600 manufactured by Ichii Co., Ltd. (composition consisting of 50 parts by mass of azodicarbonamide, an organic chemical foaming agent, 40 parts by mass of zinc oxide complex (a composition of ZnO and CaCO3 manufactured by Beisho Lime Co., Ltd.), 10 parts by mass of uric acid, and 5 parts by mass of naphthenic oil (product name: NP-24 manufactured by Idemitsu Kosan Co., Ltd.) (total 105 parts by mass)) Processing aid: sodium stearate

[0083] (Example 1) All the components shown in Example 1 in Table 1 were kneaded using a two-roll mill to obtain a composition. This composition was heat-pressed in a 10 mm thick mold at 160°C for 13 minutes to cause primary crosslinking, and then further caused secondary crosslinking at 200°C for 4 hours to obtain a perfluoroelastomer molded product with a thickness of 20 mm. The hardness, wearability, and plasma resistance of this perfluoroelastomer molded article were evaluated, and the results are shown in Table 1. In the following Examples 2, 3, 4 and 5, molded bodies were prepared in the same manner as in Example 1 and evaluated. In Table 1, the content of each component is shown in parts by mass relative to 100 parts by mass of the perfluoroelastomer or TFE-P copolymer.

[0084] [Table 1]

[0085] As shown in the results in Table 1, molded articles that did not contain carbon black and had a Shore A hardness of 25 or more and 60 or less had good mounting properties and plasma resistance (Examples 1, 2, and 3). Molded articles with excellent mounting properties can protect particle generation sources. In addition, because they have plasma resistance, they are suitable for use in semiconductor manufacturing equipment.

[0086] On the other hand, the molded articles of Examples 4 and 5, which contained carbon black, were poor in mountability and plasma resistance. When a molded article with poor mountability is used, the particle generation source cannot be protected and deteriorates. Furthermore, since the molded article itself has poor plasma resistance, it is not suitable for use in semiconductor manufacturing equipment. [Explanation of symbols]

[0087] 1. Ceramic electrostatic chuck 2 Adhesive layer 3 Cooling Plate 4 silicon wafers 5 Vacuum chamber walls 6. Top plate 7 Plasma generation mechanism 8 Protective materials 21 Adhesion layer that contributes to adhesion of the ceramic electrostatic chuck 1 to the cooling plate 3 22 Adhesion layer that does not contribute to adhesion of the ceramic electrostatic chuck 1 to the cooling plate 3

[0088] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2019-190257, filed on October 17, 2019, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A perfluoroelastomer molded article, which is a foamed article, is obtained by crosslinking a perfluoroelastomer in a perfluoroelastomer composition containing a perfluoroelastomer, which is a copolymer having units based on tetrafluoroethylene and units based on perfluoroalkyl vinyl ether, a crosslinking agent, and a blowing agent, The hydrogen atom content in the perfluoroelastomer is 0.5% by mass or less, the perfluoroelastomer is an organic peroxide-crosslinkable perfluoroelastomer, the crosslinking agent contains an organic peroxide, and the content of the organic peroxide is 0.05 to 10 parts by mass per 100 parts by mass of the perfluoroelastomer; the content of carbon black having a particle size in the range of 2 nm to 800 nm is 3 parts by mass or less relative to 100 parts by mass of the perfluoroelastomer; A perfluoroelastomer molded article having a Shore A hardness of 25 or more and 60 or less.

2. 2. The perfluoroelastomer molded article according to claim 1, which does not contain silica.

3. 3. The perfluoroelastomer molded article according to claim 1, having an Asker C hardness of 45 or more and 80 or less.

4. The perfluoroelastomer molded article according to any one of claims 1 to 3, which has a mass loss due to plasma irradiation of 10% by mass or less, as measured by the following method. Measurement method: After measuring the mass of a 2 mm thick sheet-like perfluoroelastomer molded article, it is irradiated with plasma. The plasma-irradiated perfluoroelastomer is washed with pure water, dried, and then the mass is measured again.

5. 5. The perfluoroelastomer molded article according to claim 1, wherein the organic peroxide-crosslinkable perfluoroelastomer is an elastomer having a perfluoropolyether group.

6. A protective member comprising the perfluoroelastomer molded article according to any one of claims 1 to 5.

7. The protective member according to claim 6 , wherein the size of the protective member is more than 100% and not more than 250% of the size of the gap in which the protective member is disposed.

8. 8. The protective member according to claim 6, which protects a part of a machine using plasma or chemicals that may generate particles due to exposure to the plasma or chemicals.

9. The protective member according to any one of claims 6 to 8, which is a protective member for semiconductor manufacturing equipment.

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