JP2017179210A - Fluorine elastomer composition, molded article, sealant, and plasma treatment device and semiconductor manufacturing device containing sealant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorine elastomer composition capable of enhancing plasma resistance of a fluorine elastomer and reducing fastening force or maintaining it substantially equally.SOLUTION: There is provided a fluorine elastomer composition containing at least a fluorine elastomer and yttrium oxide.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a molded product and a sealing material used in a site where plasma resistance and adhesion strength are required to be weak, a composition for forming the molded product and the sealing material, and a plasma processing apparatus including the sealing material. And a semiconductor manufacturing apparatus.

  Molded products such as sealing materials used in equipment used in environments such as plasma atmospheres and chemical atmospheres are required to have high stability against various chemical species. Molded products mainly composed of fluoroelastomers Is used (see Patent Document 1). In these devices, gas, chemical solution, etc. with high concentration and high chemical reactivity have recently been used for reasons such as efficiency improvement, and in molded products made of fluorine-based elastomers that have been widely used so far, There is a problem that it cannot be used due to severe deterioration.

  Among fluoroelastomers, perfluoroelastomer exhibits particularly excellent plasma resistance and chemical resistance, and is therefore widely used in devices used in the above severe environments (see Patent Document 2).

  Also, in the field of semiconductor manufacturing equipment, elastomer sealing materials generally have a strong adhering force and are firmly attached to the mating surface, thereby hindering the operation of the equipment and reducing maintenance efficiency. Therefore, the fluorine-containing elastomer base material includes a silicone monomer having a number average molecular weight (Mn) of 200 or more and 30,000 or less and containing only one polymerizable double bond in the molecule, a polymerization initiator, and a solvent. A surface-modified fluorine-containing elastomer in which the monomer is polymerized by contacting with a solution and then heat-treating at or above the decomposition temperature of the polymerization initiator under a specific reduced pressure, thereby modifying the surface of the fluorine-containing elastomer substrate and its vicinity. Is known to produce a plasma-resistant sealing material (see Patent Document 3).

JP 2000-119468 A JP 2000-044930 A JP 2002-348394 A

  However, when a sealing material is attached to a plasma processing apparatus or a semiconductor manufacturing apparatus, since the plasma is irradiated on the surface of the sealing material, the sealing material deteriorates from the surface. Therefore, the sealing material described in Patent Document 3 has a problem that it is vulnerable to changes over time. Furthermore, the invention described in Patent Document 3 manufactures a surface-modified fluorine-containing elastomer by a special manufacturing method. Therefore, since there is no way to use a commercially available fluoroelastomer, there is a problem in versatility. If there is an additive that can improve the plasma resistance of the fluoroelastomer and reduce or maintain almost the same level by adding and kneading it to a fluoroelastomer that is widely used as a sealing material, Function can be improved. However, currently no such additive is known.

  The present invention has been made in order to solve the above problems, and as a result of extensive research, it has surprisingly been found that the addition of yttrium oxide to a fluoroelastomer improves the plasma resistance of the fluoroelastomer and improves the solidity. That the adhesion can be reduced or maintained approximately equivalently (hereinafter, that the adhesion of the fluoroelastomer can be reduced or substantially equivalent to that before addition of yttrium oxide is sometimes referred to as “non-adhesion”). The headline was newly found and the present invention was completed.

  That is, an object of the present invention is to provide a fluoroelastomer composition that has improved plasma resistance and can be non-fixed, a molded product of the composition, a sealing material, and a plasma processing apparatus and a semiconductor manufacturing apparatus including the sealing material. It is to be.

  The present invention relates to a fluoroelastomer composition, a molded article, a sealing material, a plasma processing apparatus including the sealing material, and a semiconductor manufacturing apparatus described below.

(1) Fluoroelastomer and yttrium oxide,
A fluoroelastomer composition comprising at least
(2) The fluoroelastomer is a perfluoroelastomer.
The fluorine elastomer composition according to (1) above.
(3) The fluoroelastomer is a vinylidene fluoride / hexafluoropropene copolymer, a vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer, a tetrafluoroethylene / propylene copolymer, or a copolymer thereof. Block copolymer of vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer and tetrafluoroethylene / ethylene alternating copolymer or polyvinylidene fluoride copolymerized with ethylene or perfluoroalkyl vinyl ether At least one elastomer selected from coalescence,
The fluorine elastomer composition according to (1) above.
(4) The fluorine elastomer is
Perfluoroelastomer, and
Vinylidene fluoride / hexafluoropropene copolymer, vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer, tetrafluoroethylene / propylene copolymer, ethylene or perfluoroalkyl vinyl ether in these copolymers And a block copolymer of vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer and tetrafluoroethylene / ethylene alternating copolymer or polyvinylidene fluoride. Of elastomer,
The fluorine elastomer composition according to the above (1), comprising:
(5) further comprising silicone rubber,
The fluorine elastomer composition according to any one of (1) to (4) above.
(6) The fluoroelastomer composition is for radical resistance and non-sticking.
The fluorine elastomer composition according to any one of (1) to (5) above.
(7) The fluoroelastomer is crosslinked.
The fluorine elastomer composition according to any one of (1) to (6) above.
(8) A molded product comprising the fluoroelastomer composition according to (7) above.
(9) A sealing material comprising the fluoroelastomer composition according to (7) above.
(10) A plasma processing apparatus including the sealing material according to (9).
(11) A semiconductor manufacturing apparatus including the sealing material according to (9).

  The fluoroelastomer composition of the present invention can improve the plasma resistance of the fluoroelastomer and can be non-adhered by adding yttrium oxide. Therefore, the fluoroelastomer composition of the present invention can be used for a sealing material or the like.

FIG. 1 is a graph showing the evaluation results of the plasma resistance performance of Example 1 and Comparative Examples 1-6. FIG. 2 is a graph showing the evaluation results of the adhesion strength of Example 1 and Comparative Examples 1-6. FIG. 3 is a graph showing the evaluation results of the addition amount of yttrium oxide and the plasma resistance performance. FIG. 4 is a graph showing the evaluation results of the adhesion strength of Examples 2-3 and Comparative Examples 7-10.

  Hereinafter, the fluorine elastomer composition, molded product, sealing material, plasma processing apparatus and semiconductor manufacturing apparatus including the sealing material of the present invention will be described in detail. In the present invention, the “composition” includes both cases where the fluoroelastomer has been crosslinked (including a partially crosslinked state) and uncrosslinked. “Sealing material” refers to a material obtained by molding the fluoroelastomer composition of the present invention (hereinafter sometimes simply referred to as “composition”) into a shape suitable for sealing of an apparatus or the like, and then crosslinking and curing the composition. Means. The “molded product” means a product including a shape suitable for a seal and a shape suitable for an application other than the seal.

  The fluoroelastomer used in the composition of the present invention is a vinylidene fluoride / hexafluoropropene copolymer, a vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer, a tetrafluoroethylene / propylene copolymer, Etc. These copolymers may be further copolymerized with ethylene or perfluoroalkyl vinyl ether. In addition, a fluorine-based copolymer which is a block copolymer of fluororubber (vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer) and a fluororesin (tetrafluoroethylene / ethylene alternating copolymer and polyvinylidene fluoride). Thermoplastic elastomers can also be used. These fluorine elastomers can also be mixed (hereinafter, the fluorine elastomer described in this paragraph may be referred to as “fluorine elastomer (A)”). Although said fluorine elastomer (A) may be synthesize | combined by a well-known method, what is marketed may be used.

  Moreover, a perfluoroelastomer can also be used as a fluorine elastomer. A perfluoroelastomer is very expensive compared to a general fluoroelastomer (A), although it has excellent chemical resistance and plasma resistance. For this reason, a sealing material such as an O-ring may be formed only with perfluoroelastomer, but perfluoroelastomer can be added to and mixed with fluoroelastomer (A) to improve the plasma resistance of fluoroelastomer (A). It is also used for the purpose of improving (see, for example, Japanese Patent No. 47788782). Therefore, there has been no attempt to further improve the plasma resistance of the sealing material formed of perfluoroelastomer alone and to make it non-sticking. As shown in Examples described later, the present inventors have newly found that by adding yttrium oxide, the plasma resistance of the perfluoroelastomer itself can be further improved and non-adhered.

  The perfluoroelastomer is a copolymer unit of a perfluorovinyl ether selected from the group consisting of perfluoroolefin, perfluoro (alkyl vinyl) ether, perfluoro (alkoxy vinyl) ether, and a mixture thereof, and a curing site monomer. Perfluoroelastomers containing, and the like.

Examples of the curing site monomer include a curing site monomer containing iodine and bromine and a curing site monomer containing a cyano group. Examples of the curing site monomer containing iodine or bromine include CF ₂ ═CF (CF ₂ ) _n I, CF ₂ ═CF (CF ₂ ) _n Br, I (CF ₂ ) _n I, and the like. Examples of the cured site monomer containing a cyano group include cyano group-containing perfluorovinyl ether. For example, CF ₂ = CFO (CF ₂ ) _n OCF (CF ₃ ) CN (n: 2 to 4), CF ₂ = CFO (CF ₂ ) _n CN (n: 2 to 12), CF ₂ = CFO [CF ₂ CF (CF ₃ ) O] _m (CF ₂ ) _n CN (n: 2, m: 1 to 5), CF _{2 = CFO [CF 2 CF (} CF 3) O] m (CF 2) n CN (n: 1~4, m: 1~2), CF 2 = CFO [CF 2 CF (CF 3) O] n CF ₂ CF (CF ₃ ) CN (n: 0 to 4) and the like. The perfluoroelastomer may be synthesized by a known method, but a commercially available one may be used.

  As the fluoroelastomer, only a perfluoroelastomer having excellent chemical resistance and plasma resistance may be used, or only the fluoroelastomer (A) may be used. Further, a mixture of perfluoroelastomer and fluorine lastomer (A) may be used. In the case of mixing, as shown in the examples described later, the greater the blending ratio of the perfluoroelastomer, the more the plasma resistance is improved. Just decide.

  Moreover, you may add a silicone rubber to a composition as needed. Examples of the silicone rubber include methyl vinyl silicone rubber, methyl vinyl phenyl silicone rubber, fluoro silicone rubber, and the like. These silicone rubbers may be mixed.

Yttrium oxide (Y ₂ O ₃ ) is not particularly limited as long as it can be kneaded and dispersed in a fluorine elastomer, and commercially available yttrium oxide can be used. In addition, the commercially available yttrium oxide has a particle diameter of about 10 nm to 7 μm. When kneading yttrium oxide and fluoroelastomer using a kneader when producing the composition, if the particle size of yttrium oxide is too large, the rollers of the kneader may be damaged. Therefore, from the viewpoint of production, the particle diameter of yttrium oxide is preferably about 10 nm to 3 μm, more preferably about 10 nm to 1 μm.

  It is known that plasma resistance is improved when yttrium oxide is added to a resin (Japanese Patent Application Laid-Open No. 2011-159653). However, the above publication only describes that adding yttrium oxide to a photosensitive resist improves plasma resistance, and adding yttrium oxide to a fluoroelastomer improves plasma resistance, and The fact that they can be non-fixed is a new finding by the present inventors. As shown in the examples described later, the plasma resistance improves as yttrium oxide is added, so the lower limit of the addition amount is not particularly limited. . Note that if the amount of yttrium oxide added is too large, the rubber elasticity is lost.

  In addition, the composition of the present invention includes carbon black, calcium carbonate, silica, silicate minerals (for example, mica, talc, etc.), barium sulfate, alumina, and organic reinforcing materials as long as the effects of the present invention are not impaired. A filler, an anti-aging agent, or the like may be included.

  The composition may be uncrosslinked or crosslinked. In the case of an uncrosslinked composition, an uncrosslinked fluoroelastomer and yttrium oxide and, if necessary, a filler, an antiaging agent, etc. may be added and kneaded. For kneading, a known kneader such as an open roll, a kneader, a Banbury mixer, or a twin screw extruder may be used, but is not limited thereto. When a molded product such as a sealing material is produced from an uncrosslinked composition, a crosslinking agent or the like may be added to the uncrosslinked composition and further kneaded and then crosslinked. The uncrosslinked composition may contain a crosslinking agent or the like in advance. There is no restriction | limiting in particular about a crosslinked structure, For example, the structure of a peroxide bridge | crosslinking is mentioned.

  The cross-linking agent is not particularly limited as long as it can cross-link the fluoroelastomer. For example, the cross-linking agent may be cross-linked with an organic peroxide. As the organic peroxide crosslinking agent, known ones for crosslinking a fluorine-based elastomer can be used. For example, dicumyl peroxide, di-t-butylperoxydiisopropylbenzene, 2,5-dimethyl-2,5 -Di (t-butylperoxy) hexane, etc. are mentioned.

  As the co-crosslinking agent, a known one for crosslinking a fluorine-based elastomer can be used. For example, triallyl isocyanurate, triallyl cyanurate, triallyl trimellylate, N, N'-m-phenylene dimaleimide, trimethylolpropane trimethacrylate, and the like can be mentioned. In addition, acrylate-based and methacrylate-based monomers can also be used.

  In the case of a crosslinked composition, it can be provided by kneading an uncrosslinked fluoroelastomer, yttrium oxide, a crosslinking agent and a co-crosslinking agent, and further, if necessary, a filler, an anti-aging agent, etc., and then crosslinking. The composition after crosslinking can be formed into an expected shape by cutting or the like.

  In order to efficiently produce molded products of the desired shape such as sealing materials, first, uncrosslinked fluoroelastomer, yttrium oxide, crosslinking agent and co-crosslinking agent, and further, if necessary, filler, anti-aging An uncrosslinked composition is prepared by kneading an agent or the like. Then, a predetermined amount of uncrosslinked composition may be filled in a mold having a desired shape and crosslinked. The crosslinking may be performed by hot pressing, and if necessary, secondary crosslinking may be performed in an oven at 150 ° C. to 250 ° C. for 1 hour to 32 hours.

  Further, ionizing radiation can be used instead of the heating press. The type of ionizing radiation may be an electromagnetic wave or particle beam having the ability to ionize air directly or indirectly. Examples include, but are not limited to, α rays, β rays, γ rays, deuteron rays, proton rays, neutron rays, X rays, and electron rays. Moreover, you may use combining these radiation.

  Examples of the shape of the sealing material include a sheet shape, a rod shape, a ring shape, various complicated block shapes, and the like, depending on the application. In addition to the shape of the sealing material, the shape of the molded product includes a container shape, a plate shape, a holder for an article that requires plasma treatment, and the like. For example, when placing an article requiring plasma treatment in a chamber, a holder is formed that holds the article and exposes the part that requires plasma treatment and covers the part that does not require plasma treatment. Thus, the desired article can be plasma treated in the chamber. By adding yttrium oxide, the molded product becomes non-fixed, so that the separation of the article after the plasma treatment becomes easier as compared with the conventional case.

Since the composition of the present invention has the above-mentioned characteristics, a molded article using the composition of the present invention is suitable for use under severe environments such as high temperature and vacuum. Therefore, it can be incorporated as a molded product in a plasma processing apparatus or semiconductor manufacturing apparatus exposed to plasma. The type of plasma gas is not limited. For example, in a plasma processing apparatus, O ₂ , CF ₄ , O ₂ + CF ₄ , H ₂ , CHF ₃ , CH ₃ F, CH ₂ F ₂ , Cl ₂ , C ₂ F ₆ , BCl ₃ , NF ₃ , NH _{3 and the} like are common, but the molded product of the present invention has excellent resistance to any plasma.

  The present invention will be described in detail with reference to the following examples, which are provided merely for the purpose of illustrating the present invention and for reference to specific embodiments thereof. These exemplifications are for explaining specific specific embodiments of the present invention, but are not intended to limit or limit the scope of the invention disclosed in the present application.

<< Example 1, Comparative Examples 1-6 >>
(1) Manufacture of sealing materials with various additives <Raw materials>
The following products were used as raw materials.
・ Perfluoroelastomer: manufactured by 3M Japan ・ Co-crosslinking agent: manufactured by Nippon Kasei Co., Ltd., TAIC
・ Cross-linking agent: manufactured by Nippon Oil & Fats, Perhexa 25B
Various additives Yttrium oxide (Y ₂ O ₃ ): Shin-Etsu Chemical Co., Ltd., particle size of about 20 nm
Aluminum oxide (Al ₂ O ₃ ): manufactured by CIK Silicon carbide (SiC): manufactured by Enetech Soken Co., Ltd. Polytetrafluoroethylene (PTFE): manufactured by 3M Japan Co., Ltd. Aluminum nitride (AlN): manufactured by Tokuyama Corporation Carbon: manufactured by Cancarb

<Preparation of uncrosslinked composition>
An uncrosslinked composition was prepared by charging the kneaded material into a biaxial open roll (manufactured by Irie Iron Works Co., Ltd.) so as to have the composition shown in Table 1 and kneading.

<Molding temperature and molding time>
First, an appropriate amount of the above-mentioned uncrosslinked composition was charged into an MDR apparatus (manufactured by Flexsys, RHEOMETER MDR 2000). And the test was implemented at 150 degreeC and 1 hour, and the data of Tc90 used as the parameter | index of molding time were obtained.

<Molding, secondary cross-linking (O-ring production)>
An appropriate amount of an uncrosslinked composition was charged into an O-ring mold (AS568-214 size) heated to 150 ° C. Next, a sample to which various additives were added was molded at a time 1.2 times the time determined based on Tc90 calculated by MDR. After molding, the molded body was taken out from the mold, and unnecessary burrs were removed. And secondary crosslinking was implemented for 4 hours in 180 degreeC oven, and the sealing material using the bridge | crosslinked composition was manufactured.

(2) Evaluation of plasma resistance Plasma was exposed to the manufactured sealing material under the following conditions, and the plasma resistance was evaluated by the mass reduction rate of the sealing material before and after the exposure.
・ Device: RIE-200IP manufactured by Samco
・ Sealant: φ3.53 × 30mm (AS568-214 size cut product)
Gas: O ₂ / CF ₄ = 16/16
・ Processing pressure: 2.66 Pa
・ Output: 900W
・ Exposure time: 10 min
Weight reduction rate (% by weight) = [(weight before plasma exposure−weight immediately after plasma exposure) / (weight before plasma exposure)] × 100

  FIG. 1 is a graph showing the evaluation results of the plasma resistance of Example 1 and Comparative Examples 1-6. As is apparent from FIG. 1, it has been clarified that the addition of yttrium oxide and aluminum oxide can further improve the plasma resistance of the perfluoroelastomer, which is said to have high plasma resistance.

(3) Evaluation of adhesion strength The adhesion strength of the produced sealing material was evaluated by the following procedure.
(A) The sealing material (AS568-214 size) was fitted into a dovetail groove member made of SUS304 that can be compressed by 25%.
(A) A 5052 alumite plate was brought into close contact with the member fitted with the sealing material, and the sealing material was crushed by tightening with a bolt. In that state, it was put into an oven and heated at 200 ° C. for 22 hours.
(C) After completion of heating, it was taken out from the oven and cooled in air to 23 ° C. ± 2 ° C.
(D) The member in which the groove was formed was fixed to the base, and the force to peel off the A5052 alumite plate was measured with an autograph (Shimadzu Corporation, AG 50 kN). The measurement was performed under the conditions of 23 ° C. ± 2 ° C. and a tensile speed of 10 ± 1 mm / min.

  FIG. 2 is a graph showing the evaluation results of the adhesion strength of Example 1 and Comparative Examples 1-6. As is clear from FIG. 2, only the yttrium oxide was found to be non-adherent in the produced sealing material by adding to the perfluoroelastomer. The other additives, on the contrary, increased the adhesive strength of the sealing material. From the above results, a plurality of additives such as aluminum oxide that can be improved in plasma resistance by adding to perfluoroelastomer have been clarified. However, only yttrium oxide can improve plasma resistance and can be non-fixed. It became clear that.

(4) Evaluation of addition amount of yttrium oxide and plasma resistance The sealing material which changed the addition amount of the yttrium oxide of the said Example 1 was produced, and plasma resistance was evaluated in the procedure similar to the above.
FIG. 3 is a graph showing the amount of yttrium oxide added and the evaluation results of plasma resistance. As shown in FIG. 3, it became clear that plasma resistance is improved by increasing the amount of yttrium oxide added.

<< Examples 2-3, Comparative Examples 7-10 >>
(1) Evaluation of Adhesive Strength when Added to Various Fluoroelastomers Next, when only the fluoroelastomer (A) is used as the fluoroelastomer and when the fluoroelastomer (A) + perfluoroelastomer is used, The wearing power was evaluated. Evaluation was performed by producing a sealing material in the same procedure as in Example 1 and Comparative Examples 1 to 6 except that raw materials having a blending ratio shown in Table 2 below were used, and evaluating the fixing force. In addition, Solvay P959 was used for the fluorine elastomer.

FIG. 4 is a graph showing the evaluation results of Examples 2-3 and Comparative Examples 7-10. For comparison, the evaluation results of Example 1 and Comparative Examples 1 and 2 are also shown in the graph.
As is clear from FIG. 4, when yttrium oxide is added to the fluoroelastomer (A) + perfluoroelastomer (Example 2) and when yttrium oxide is added to the fluoroelastomer (A) (Example 3), The adhesion strength was almost the same as in Comparative Examples 8 and 10 in which yttrium oxide was not added. On the other hand, in the same manner as in Comparative Example 2, the radical resistance was better than that of yttrium oxide when aluminum oxide was added to the fluoroelastomer (A) + perfluoroelastomer (Comparative Example 7) and to the fluoroelastomer (A). In the case (Comparative Example 9), the adhesive strength of the sealing material was stronger than before the addition.

  From the above results, it has been clarified that, among various additives, only yttrium oxide can not only improve the plasma resistance but also be non-adhered when added to the fluoroelastomer.

In the composition of the present invention, the addition of yttrium oxide improves the plasma resistance of the fluoroelastomer and makes it non-sticking. Therefore, when a molded product such as a sealing material is produced using the composition of the present invention, operability such as maintenance of a plasma processing apparatus, a semiconductor manufacturing apparatus and the like is improved, and thus is useful for the semiconductor industry and the like.

Claims (11)

Fluorine elastomer and yttrium oxide,
A fluoroelastomer composition comprising at least The fluoroelastomer is a perfluoroelastomer,
The fluorine elastomer composition according to claim 1. The fluoroelastomer is a vinylidene fluoride / hexafluoropropene copolymer, a vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer, a tetrafluoroethylene / propylene copolymer, ethylene in these copolymers Or a copolymer of perfluoroalkyl vinyl ether, selected from a block copolymer of vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer and tetrafluoroethylene / ethylene alternating copolymer or polyvinylidene fluoride At least one elastomer,
The fluorine elastomer composition according to claim 1. The fluorine elastomer is
Perfluoroelastomer, and
Vinylidene fluoride / hexafluoropropene copolymer, vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer, tetrafluoroethylene / propylene copolymer, ethylene or perfluoroalkyl vinyl ether in these copolymers And a block copolymer of vinylidene fluoride / hexafluoropropene / tetrafluoroethylene copolymer and tetrafluoroethylene / ethylene alternating copolymer or polyvinylidene fluoride. Of elastomer,
The fluorine elastomer composition according to claim 1, comprising: Further comprising silicone rubber,
The fluorine-elastomer composition as described in any one of Claims 1-4. The fluorine elastomer composition is for radical resistance and non-sticking,
The fluorine-elastomer composition as described in any one of Claims 1-5. The fluoroelastomer is cross-linked,
The fluorine elastomer composition according to any one of claims 1 to 6.   A molded article comprising the fluoroelastomer composition according to claim 7.   A sealing material comprising the fluoroelastomer composition according to claim 7.   A plasma processing apparatus comprising the sealing material according to claim 9. The semiconductor manufacturing apparatus containing the sealing material of Claim 9.