Plasma etching resistant fluororubber material, preparation method and application on semiconductor equipment

Abstract

The present application relates to the technical field of fluororubber material, and particularly relates to a fluororubber material resistant to plasma corrosion, a preparation method and application thereof on semiconductor equipment. The fluororubber material is prepared by mixing and vulcanizing fluororubber raw rubber, perfluoropolyether additive, surface-modified rare earth fluoride, surface-modified fumed silica, peroxide vulcanizing agent, co-vulcanizing agent and vulcanization accelerator. The affinity between the surface-modified fumed silica and the perfluoropolyether additive is stronger than that between the surface-modified fumed silica and the fluororubber matrix, and the polarity / surface energy difference between the perfluoropolyether additive and the fluororubber matrix drives the fumed silica to migrate and concentrate to the material surface layer region with lower interface energy, forming an interface modification layer, and the uniformly dispersed rare earth fluoride in the interior can capture residual F free radicals penetrating the surface layer, forming a synergistic protection mechanism.

Description

Technical Field

[0001] This invention relates to the field of fluororubber materials technology, specifically to a plasma-resistant fluororubber material, its preparation method, and its application in semiconductor devices. Background Technology

[0002] As semiconductor manufacturing processes evolve towards smaller feature sizes and higher integration, processes such as plasma etching, deposition, and cleaning place stringent demands on the corrosion resistance of internal components. Fluororubber, due to its excellent chemical stability and resistance to high temperatures and chemical media, is widely used in critical components of semiconductor equipment, such as seals, valve diaphragms, and cavity gaskets. However, in plasma environments containing fluorine, oxygen, and high-energy ion bombardment, traditional fluororubber materials are prone to surface degradation, weight loss, crack propagation, and seal failure, directly impacting process stability and equipment lifespan.

[0003] In existing technologies, improving the plasma corrosion resistance of fluororubber mainly focuses on three aspects: First, increasing the degree of perfluorination of rubber by introducing monomers such as perfluoromethyl vinyl ether or perfluoroalkyl vinyl ether, such as perfluoroether rubber (FFKM), but these materials are extremely expensive and have a narrow processing window; Second, adding inorganic fillers such as alumina, yttrium oxide, silicon dioxide, or boron nitride in an attempt to delay plasma erosion through physical shielding, but the interface between the filler and the matrix is ​​weak, and it is easy to detach under plasma bombardment or introduce particulate contaminants due to filler detachment, which is not suitable for semiconductor chamber environments with high cleanliness requirements; Third, using peroxide or bisphenol vulcanization systems to adjust the crosslinking density to enhance the overall compactness of the rubber, but excessive crosslinking will reduce elasticity, resulting in a decrease in sealing compensation ability.

[0004] To address the aforementioned problems, this invention provides a plasma-resistant fluororubber material and its preparation method, aiming to effectively improve its durability and sealing reliability under plasma conditions in semiconductor equipment through synergistic optimization of material composition and structural design without significantly increasing costs. Summary of the Invention

[0005] This invention aims to address the problems of insufficient corrosion resistance of fluororubber materials in plasma environments, easy detachment of fillers, and excessively high cost of highly perfluorinated materials in the prior art. It provides a plasma-resistant fluororubber material and its preparation method. Without significantly increasing costs, the material's corrosion resistance and long-term sealing reliability in fluorine-containing plasma environments are significantly improved through the synergistic effect of filler system design and interfacial chemical bonding.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a plasma-resistant fluororubber material includes the following steps:

[0008] Step 1: Weigh the following raw material components by weight percentage:

[0009] 100 parts of fluororubber raw rubber, 2-8 parts of perfluoropolyether additives, 10-25 parts of surface-modified rare earth fluorides, 3-10 parts of surface-modified fumed silica, 0.5-6 parts of peroxide vulcanizing agent, 1-8 parts of co-vulcanizing agent, and 0.1-3 parts of vulcanization accelerator;

[0010] Step 2: Mix a portion of the fluororubber raw rubber with perfluoropolyether additives and knead to obtain masterbatch;

[0011] Step 3: Add the remaining portion of the fluororubber raw rubber to the masterbatch, mix, and then add surface-modified rare earth fluorides to mix again to obtain the first compound.

[0012] Step 4: Add surface-modified fumed silica to the first compound and mix to obtain the second compound.

[0013] Step 5: Add peroxide vulcanizing agent, co-vulcanizing agent and vulcanization accelerator to the second compound in sequence, and mix to obtain the compound;

[0014] Step 6: Perform a single vulcanization on the compounded rubber to obtain a single-vulcanized product;

[0015] Step 7: Perform a second vulcanization on the product after primary vulcanization to obtain a fluororubber material resistant to plasma corrosion.

[0016] Preferably, in step one: the fluororubber raw rubber includes a terpolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene;

[0017] The Mooney viscosity ML(1+10)121℃ of the vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer is 20-40.

[0018] Preferably, in step one: the perfluoropolyether additive includes at least one of perfluoropolyether carboxylic acid and polyhexafluoropropylene oxide monoethanol.

[0019] Preferably, in step one: the surface-modified rare earth fluoride includes a coupling agent-modified rare earth fluoride;

[0020] The coupling agent includes an aluminate coupling agent;

[0021] The rare earth fluorides include yttrium fluoride (YF3).

[0022] Preferably, the coupling agent may further include a titanate coupling agent;

[0023] The rare earth fluorides may also include at least one of cerium fluoride and lanthanum fluoride.

[0024] Preferably, in step one: the surface-modified fumed silica includes fluorosilane coupling agent-modified fumed silica;

[0025] The fluorosilane coupling agent includes tridecafluorooctyltriethoxysilane.

[0026] Preferably, the fluorosilane coupling agent may further include any one of trifluoropropyltrimethylsilane, heptadecafluorodecyltrimethoxysilane, and perfluorooctyltrichlorosilane.

[0027] Preferably, in step one: the peroxide vulcanizing agent includes any one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, and tert-butyl peroxide; the co-vulcanizing agent includes triallyl isocyanurate; and the vulcanization accelerator includes at least one of N,N'-m-phenylene bismaleimide, zinc dimethacrylate, and magnesium methacrylate.

[0028] Preferably, in step two: a portion of the fluororubber raw rubber accounts for 15%-45% of the total mass of the fluororubber raw rubber, and the mixing conditions are mixing at 30-50℃ for 4-8 minutes; in step three: the mixing conditions are mixing at 30-50℃ for 3-5 minutes, and the surface-modified rare earth fluorides are added in batches, with each batch of surface-modified rare earth fluorides being mixed at 30-50℃ for 2-4 minutes after addition; in step four: the mixing conditions are mixing at 30-50℃ for 4-8 minutes; in step five: the mixing conditions are mixing at 30-50℃ for 3-6 minutes.

[0029] Preferably, in step six: the primary vulcanization is carried out at a temperature of 160-180℃ and a pressure of 5-25MPa, and the vulcanization time is 8-30min;

[0030] In step seven: the secondary vulcanization is carried out at a temperature of 200-250℃ for 8-24 hours;

[0031] The heating rate for secondary vulcanization is 0.3-1.5℃ / min.

[0032] In the above preparation method, during the mixing process, the surface-modified fumed silica particles exhibit significantly higher affinity between the fumed silica and the perfluoropolyether additive than between the fumed silica and the fluororubber matrix. Simultaneously, the perfluoropolyether additive and the fluororubber matrix have low compatibility due to significant differences in polarity / surface energy. Driven by thermodynamics, the fumed silica particles are preferentially wetted by the perfluoropolyether additive, forming a filler-additive composite. This composite tends to migrate towards the material surface region with lower interfacial energy and, under the subsequent mixing flow field and the venting effect before vulcanization, further accumulates in the material surface region, forming an interfacial modified layer with a higher nanoparticle density than the material interior. The rare earth fluoride particles are uniformly dispersed within the fluororubber material. Furthermore, the reactive functional groups on the perfluoropolyether additive chemically bond with the active silanol groups on the surface of the fumed silica particles and the reactive groups in the fluorosilane coupling agent molecules during vulcanization, forming a molecular bridging network across the interfacial layer.

[0033] The present invention also discloses a plasma-resistant fluororubber material, which is prepared by the preparation method described above.

[0034] Application of a plasma-resistant fluororubber material, as described above, in semiconductor devices.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] This invention utilizes the stronger affinity of surface-modified fumed silica to perfluoropolyether additives than to fluororubber matrices, as well as the polarity / surface energy difference between the perfluoropolyether additives and the fluororubber matrix. During the mixing process, the fumed silica is preferentially wetted by the perfluoropolyether additives to form a composite. This composite migrates and accumulates in the lower interfacial energy surface region of the material, forming an interface-modified layer. This achieves selective distribution of fillers in the thickness direction of the material, unlike existing technologies that rely on uniform dispersion or simple surface coating. The surface-enriched fumed silica transforms into a dense Si-O-Si network passivation layer in a plasma environment, effectively blocking the diffusion of active free radicals into the material interior. Simultaneously, uniformly dispersed rare-earth fluoride particles inside capture residual F free radicals that penetrate the surface. This synergistic mechanism of surface blocking and internal capture results in significantly better corrosion resistance in fluorine-containing plasma environments compared to existing ordinary fluororubber materials.

[0037] In this invention, the reactive functional groups (carboxyl or hydroxyl groups) of the perfluoropolyether additive chemically bond with the active silanol groups on the surface of fumed silica and the reactive groups in the fluorosilane coupling agent molecules during vulcanization, forming a molecular bridging network across the interface layer. This connects the surface nanofiller, the interface transition layer, and the rubber matrix into a whole, solving the problem of weak interfacial bonding between the filler and the fluororubber matrix in the prior art, which is prone to detachment under plasma bombardment. At the same time, this molecular bridging network makes the vulcanization crosslinking density more uniform. In addition, the uniformly dispersed rare earth fluorides inside act as rigid fillers to enhance the integrity of the crosslinking network and regulate the vulcanization kinetics. This results in the compression set of the sealing element being less than 30% after 200 hours of exposure at 200°C and 25% compression ratio, maintaining the elastic recovery capability required for long-term sealing while maintaining corrosion resistance. Attached Figure Description

[0038] Figure 1 This is a molecular structure diagram of the perfluoropolyether carboxylic acid used in Example 1 of the present invention;

[0039] Figure 2 This is a molecular structure diagram of polyhexafluoropropylene oxide monoethanol used in Example 2 of the present invention. Detailed Implementation

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment discloses a method for preparing a plasma-resistant fluororubber material, comprising the following steps:

[0043] Step 1: Weigh the following raw material components by weight percentage:

[0044] 100 parts of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer (Viton® AL-300, Mooney viscosity ML(1+10) 121℃ is 30, fluorine content is 66%), 2 parts of perfluoropolyether carboxylic acid (commercially available, average molecular weight is 1000), 10 parts of coupling agent modified rare earth fluoride, 3 parts of surface modified fumed silica, 0.5 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1 part of triallyl isocyanurate, and 0.1 parts of N,N'-m-phenylene bismaleimide;

[0045] The surface-modified fumed silica is tridecafluorooctyltriethoxysilane-modified fumed silica, prepared by the following steps:

[0046] Fumed silica (average particle size of 100 nm) was added to ethanol and ultrasonically dispersed at 50 kHz for 30 min. Triethylamine was added to adjust the pH to 9, and then tridecafluorooctyltriethoxysilane was added. The mass ratio of fumed silica, tridecafluorooctyltriethoxysilane and ethanol was 1:0.4:60. The reaction was carried out at 60 °C for 5 h. After the reaction was completed, the mixture was centrifuged. The precipitate was washed three times with ethanol and dried in a vacuum drying oven at 50 °C until constant weight to obtain tridecafluorooctyltriethoxysilane modified fumed silica.

[0047] Surface-modified rare earth fluorides, including aluminate coupling agent-modified yttrium fluoride, are prepared by the following steps:

[0048] Yttrium fluoride (specification: 100 nm) and (3-oxobutyrate ethyl ester-O1',O3)bis(propanol-2-)aluminum were added to ethanol. The mass ratio of yttrium fluoride, (3-oxobutyrate ethyl ester-O1',O3)bis(propanol-2-)aluminum and ethanol was 2:1.8:40. After ultrasonic dispersion at 50 kHz for 30 min, the mixture was stirred at 55 °C for 2 h at 800 r / min. After the reaction was completed, the mixture was filtered and dried in a vacuum drying oven at 50 °C to constant weight to obtain aluminate coupling agent modified yttrium fluoride.

[0049] Step 2: Mix 15% of the total mass of the vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer with perfluoropolyether carboxylic acid and knead at 30°C for 8 minutes to obtain the masterbatch.

[0050] Step 3: Add the remaining portion of the fluororubber raw rubber (accounting for 85% of the total mass of the fluororubber raw rubber) to the masterbatch. After mixing at 30°C for 5 minutes, add the aluminate coupling agent modified yttrium fluoride in three equal batches. After each batch of aluminate coupling agent modified yttrium fluoride is added, mix at 30°C for 4 minutes to obtain the first compound.

[0051] Step 4: Add tridecafluorooctyltriethoxysilane-modified fumed silica to the first compound and mix at 30°C for 8 minutes to obtain the second compound.

[0052] Step 5: Add 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, triallyl isocyanurate and N,N'-m-phenylene bismaleimide to the second compound in sequence, and mix at 30°C for 8 minutes to obtain the compound.

[0053] Step 6: Perform a primary vulcanization on the compound rubber at a temperature of 160℃ and a pressure of 5MPa for 30 minutes to obtain a primary vulcanized product.

[0054] Step 7: Perform a second vulcanization on the product after primary vulcanization. The second vulcanization is carried out at 200℃ for 24 hours to obtain a fluororubber material resistant to plasma corrosion.

[0055] Example 2

[0056] This embodiment discloses a method for preparing a plasma-resistant fluororubber material, comprising the following steps:

[0057] Step 1: Weigh the following raw material components by weight percentage:

[0058] 100 parts of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer (Viton® AL-300, Mooney viscosity ML(1+10) 121℃ is 30, fluorine content is 66%), 8 parts of polyhexafluoropropylene oxide monoethanol (commercially available, average molecular weight is 1000), 25 parts of coupling agent modified rare earth fluoride, 10 parts of surface modified fumed silica, 6 parts of dicumyl peroxide, 8 parts of triallyl isocyanurate, and 3 parts of zinc dimethacrylate.

[0059] Among them, the surface-modified fumed silica is tridecafluorooctyltriethoxysilane-modified fumed silica, and the preparation method is the same as in Example 1;

[0060] Surface-modified rare earth fluorides include yttrium fluoride modified with aluminate coupling agent, and the preparation method is the same as in Example 1;

[0061] Step 2: Mix 45% of the total mass of the vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer with polyhexafluoropropylene oxide monomethanol, and knead at 50°C for 4 minutes to obtain the masterbatch.

[0062] Step 3: Add the remaining portion of the fluororubber raw rubber (accounting for 55% of the total mass of the fluororubber raw rubber) to the masterbatch. After mixing at 50°C for 3 minutes, add the aluminate coupling agent modified yttrium fluoride in five equal batches. After each batch of aluminate coupling agent modified yttrium fluoride is added, mix at 50°C for 2 minutes to obtain the first compound.

[0063] Step 4: Add tridecafluorooctyltriethoxysilane-modified fumed silica to the first compound and mix at 50°C for 4 minutes to obtain the second compound.

[0064] Step 5: Add dicumyl peroxide, triallyl isocyanurate, and zinc dimethacrylate to the second compound in sequence, and mix at 50°C for 3 minutes to obtain the compound.

[0065] Step 6: Perform a primary vulcanization on the compound rubber at a temperature of 180℃ and a pressure of 25MPa for 8 minutes to obtain a primary vulcanized product.

[0066] Step 7: Perform a second vulcanization on the product after primary vulcanization. The second vulcanization is carried out at 250℃ for 8 hours to obtain a fluororubber material resistant to plasma corrosion.

[0067] Example 3

[0068] This embodiment discloses a method for preparing a plasma-resistant fluororubber material, comprising the following steps:

[0069] Step 1: Weigh the following raw material components by weight percentage:

[0070] 100 parts of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer (Viton® AL-300, Mooney viscosity ML(1+10) 121℃ is 30, fluorine content is 66%), 2.5 parts of perfluoropolyether carboxylic acid (commercially available, average molecular weight 1000), 2.5 parts of polyhexafluoropropylene oxide monoethanol (commercially available, average molecular weight 1000), 18 parts of coupling agent modified rare earth fluoride, 6 parts of surface modified fumed silica, 3.5 parts of tert-butyl peroxide, 5 parts of triallyl isocyanurate, and 2 parts of magnesium methacrylate;

[0071] Among them, the surface-modified fumed silica is tridecafluorooctyltriethoxysilane-modified fumed silica, and the preparation method is the same as in Example 1;

[0072] Surface-modified rare earth fluorides include yttrium fluoride modified with aluminate coupling agent, and the preparation method is the same as in Example 1;

[0073] Step 2: Mix 30% of the total mass of the vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer with perfluoropolyether carboxylic acid and knead at 40°C for 6 minutes to obtain the masterbatch.

[0074] Step 3: Add the remaining portion of the fluororubber raw rubber (accounting for 70% of the total mass of the fluororubber raw rubber) to the masterbatch. After mixing at 40°C for 4 minutes, add the aluminate coupling agent modified yttrium fluoride in four equal batches. After each batch of aluminate coupling agent modified yttrium fluoride is added, mix at 40°C for 3 minutes to obtain the first compound.

[0075] Step 4: Add tridecafluorooctyltriethoxysilane-modified fumed silica to the first compound and mix at 40°C for 6 minutes to obtain the second compound.

[0076] Step 5: Add tert-butyl peroxide, triallyl isocyanurate, and magnesium methacrylate to the second compound in sequence, and mix at 40°C for 5 minutes to obtain the compound.

[0077] Step 6: Perform a primary vulcanization on the compound rubber at a temperature of 170℃ and a pressure of 15MPa for 20 minutes to obtain a primary vulcanized product.

[0078] Step 7: Perform a second vulcanization on the product after primary vulcanization. The second vulcanization is carried out at 230℃ for 16 hours to obtain a fluororubber material resistant to plasma corrosion.

[0079] Comparative Example 1

[0080] This comparative example discloses a method for preparing a plasma-resistant fluororubber material. The only difference from Example 1 is that the raw material component lacks surface-modified fumed silica, and the missing part is made up by a terpolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene.

[0081] Comparative Example 2

[0082] This comparative example discloses a method for preparing a plasma-resistant fluororubber material. The only difference from Example 1 is that the raw material components lack coupling agent-modified rare earth fluorides, and the missing part is made up by a terpolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene.

[0083] Comparative Example 3

[0084] This comparative example discloses a method for preparing a plasma-resistant fluororubber material. The only difference from Example 1 is that the raw material component lacks perfluoropolyether carboxylic acid, and the missing part is made up by a terpolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene.

[0085] Test case

[0086] The properties of the plasma-resistant fluororubber material samples prepared in Examples 1-3 and Comparative Examples 1-3 were determined:

[0087] (1) Mechanical property determination: Referring to standard GB / T531.1-2008, the Shore hardness of the fluororubber material sample (thickness of 6 mm) was determined at room temperature using a Shore hardness tester; Referring to standard GB / T528-2009, the tensile strength and elongation at break of the fluororubber material sample (dumbbell type) were determined using a universal tensile testing machine at a tensile speed of 500±50 mm / min; Referring to standard GB / T529-2008, the tear strength of the fluororubber material sample (right angle type) was determined using a universal tensile testing machine at a tensile speed of 500±50 mm / min; Referring to standard GB / T7759.1-2015, the compression set of the fluororubber material sample (type A) was determined using a compression set tester at 200℃×24h and a compression rate of 25%.

[0088] (2) Surface performance determination: Referring to standard GB / T30447-2013, the static water contact angle of the fluororubber material sample was determined using a contact angle measuring instrument (JC2000C1 type) at room temperature and relative humidity of 50±5% with deionized water as the test liquid.

[0089] (3) Plasma corrosion resistance test: Referring to the test specifications for CVD / etching equipment seals in the semiconductor industry, CF4 / O2 mixed gas (volume ratio 4:1) was used as the plasma gas. The fluororubber material sample (20mm×20mm×2mm) was treated under the conditions of RF power of 300W, cavity gas pressure of 10Pa, and gas flow rate of 100sccm for 60min. The mass loss rate, etching rate, hardness change rate, tensile strength retention rate and surface morphology of the treated fluororubber material sample were measured.

[0090] The results of the mechanical property tests are shown in Table 1:

[0091] Table 1

[0092] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Shore A hardness 72 82 78 65 68 63 Tensile strength (MPa) 15.2 17.8 16.5 12.5 10.8 11.2 Elongation at break (%) 280 245 262 310 295 320 Tear strength (kN / m) 32.5 38.2 35.6 26.3 24.1 23.5 Compression set (%) 28 22 25 35 38 42

[0093] As shown in Table 1, the fluororubber material prepared by this invention has good mechanical properties. Compared with Example 1, in Comparative Example 1, the absence of surface-modified fumed silica resulted in a decrease in Shore hardness, tensile strength, and tear strength, and an increase in compression set. This indicates that fumed silica, as a rigid filler, forms a rigid skeleton in the rubber matrix, restricting the relative slippage of molecular chains. Although the crosslinking density of the matrix did not change significantly after the absence of fumed silica, the lack of the rigid filler network made the molecular chains more prone to untangling and slippage during stretching, manifested as an increase in elongation at break, a decrease in modulus, and an increase in compression set. In Comparative Example 2, the absence of coupling agent-modified rare earth fluorides also led to a decrease in Shore hardness, tensile strength, and tear strength, and an increase in compression set. This indicates that after modification with the coupling agent, the rare earth fluorides form a good interfacial bond with the rubber matrix, effectively transferring stress and restricting premature slippage of molecular chains during stretching. After the absence of rare earth fluorides, the effective physical crosslinking points in the rubber matrix decreased, and the movement of molecular chains was restricted. The reduced degree of limitation leads to an increase in elongation at break but a significant decrease in strength. In Comparative Example 3, the absence of perfluoropolyether carboxylic acid resulted in a decrease in Shore hardness, tensile strength, and tear strength, while an increase in compression set and elongation at break. The perfluoropolyether additive plays a dual role in this invention: firstly, it drives the migration and enrichment of fumed silica to the surface; secondly, it chemically bonds with the silanol groups and fluorosilane molecules on the surface of fumed silica through its reactive functional groups, forming a molecular bridging network across the interface layer. Without the perfluoropolyether additive, there is a lack of effective chemical bonding between the filler and the rubber matrix, relying only on physical coating and mechanical interlocking. During stretching, the interface between the filler and the matrix is ​​prone to debonding, increasing the free movement space of the rubber molecular chains. Macroscopically, this manifests as a significant increase in elongation at break, but the stress cannot be effectively transferred to the filler particles, leading to a significant decrease in tensile strength. At the same time, after high-temperature compression, the permanent deformation increases significantly due to interface slippage.

[0094] The surface properties test results are shown in Table 2:

[0095] Table 2

[0096] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Static water contact angle (°) 118 125 121 99 108 102

[0097] As shown in Table 2, the fluororubber material prepared by this invention exhibits excellent surface hydrophobic properties. Compared with Example 1, Comparative Example 1, lacking surface-modified fumed silica, showed a decrease in static water contact angle, indicating that the material surface became weakly hydrophobic. This demonstrates that surface-modified fumed silica is the key component in elevating the fluororubber material from intrinsically hydrophobic to highly hydrophobic. The micro-rough structure formed by its migration and enrichment to the surface under the drive of perfluoropolyether additives significantly increases the contact angle. The absence of this component reduces the surface hydrophobicity, making it easier for active free radicals in the plasma environment to adsorb onto the surface and accelerate the corrosion process. Comparative Example 2, lacking coupling agent-modified rare earth fluorides, showed a decrease in static water contact angle, but it remained significantly higher than that of Comparative Example 1. This indicates that the absence of rare earth fluorides has a relatively limited impact on surface hydrophobicity, and the material still maintains a good hydrophobic state. The slight decrease in contact angle is mainly attributed to... The absence of rare earth fluorides as reinforcing fillers alters the vulcanization kinetics and volume shrinkage characteristics of the rubber compound, leading to a decrease in the density and orderliness of the surface fumed silica, an incomplete micro-rough structure, and a weakened hydrophobic effect. In Comparative Example 3, the absence of perfluoropolyether carboxylic acid resulted in a reduced static water contact angle, indicating that the perfluoropolyether additive plays a key driving role in the enrichment of fumed silica on the surface. Its reactive functional groups (carboxyl or hydroxyl groups) chemically bond with the active silanol groups and fluorosilane coupling agent molecules on the surface of fumed silica during vulcanization, forming a molecular bridging network across the interfacial layer. Without this additive, fumed silica cannot effectively migrate to the surface, or although it migrates to the surface, its bonding with the matrix interface is weakened, failing to form a complete and dense low surface energy modified layer, resulting in a significant deterioration of the surface hydrophobic properties.

[0098] The results of the plasma corrosion resistance test are shown in Table 3:

[0099] Table 3

[0100] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Quality loss rate (%) 0.28 0.18 0.22 0.85 1.20 1.05 Etching rate (pg / cm 2 • h) 85 55 68 260 365 320 Hardness change rate (%) -2.1 -1.5 -1.8 -5.2 -8.5 -7.2 Tensile strength retention rate (%) 91 94 92 78 65 68 Surface morphology Smooth surface with minor corrosion spots The surface is smooth and there is no obvious corrosion. Smooth surface with very slight corrosion Rough surface with obvious etching pits Severe corrosion, numerous cracks Severe corrosion, surface peeling

[0101] As shown in Table 3, the fluororubber material prepared by this invention exhibits excellent resistance to plasma corrosion. Compared with Example 1, Comparative Example 1, lacking surface-modified fumed silica, showed a significant increase in mass loss rate, etching rate, and hardness change rate, a decrease in tensile strength retention, and a change in surface morphology from slight corrosion points to obvious etching pits. This indicates that the surface-enriched fumed silica can be transformed into a dense Si-O-Si network passivation layer in the plasma environment, effectively preventing the diffusion of active free radicals (such as F·) into the material interior. Its absence resulted in the material surface being directly exposed to plasma bombardment, allowing active free radicals to erode the rubber matrix without hindrance, leading to a significant increase in corrosion rate and a substantial decrease in mechanical properties. Comparative Example 2, lacking coupling agent-modified rare earth fluorides, showed a substantial increase in mass loss rate, etching rate, and hardness change rate, a significant decrease in tensile strength retention, and a surface morphology exhibiting severe corrosion accompanied by numerous cracks. This indicates that rare earth fluorides are the core functional component for resisting plasma corrosion. Through the strong bonding energy of YF bonds and low sputtering characteristics, it plays a bulk protective role in capturing residual F free radicals that penetrate the surface layer within the material. The absence of this component leads to the lack of an effective free radical capturing barrier inside the material. Once the surface layer is breached, the internal matrix degrades rapidly, and the overall corrosion resistance collapses. In Comparative Example 3, the absence of perfluoropolyether carboxylic acid also significantly reduced the plasma corrosion resistance, indicating that the perfluoropolyether additive has an irreplaceable dual function in this invention: on the one hand, the polarity difference between it and fumed silica drives fumed silica to migrate and accumulate to the surface, forming an interface modification layer; on the other hand, its reactive functional groups (carboxyl, hydroxyl, or epoxy groups) chemically bond with the active silanol groups and fluorosilane coupling agent molecules on the surface of fumed silica during vulcanization, forming a molecular bridging network across the interface layer, connecting the surface protective layer, the interface transition zone, and the rubber matrix into a whole. The absence of this additive prevents fumed silica from being effectively enriched on the surface, and the particles enriched on the surface lack chemical bonds with the matrix, making them prone to detachment and failure under plasma bombardment, thus causing the material to lose its protective capabilities.

[0102] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a plasma-resistant fluororubber material, characterized in that, Includes the following steps: Step 1: Weigh the following raw material components by weight percentage: 100 parts of fluororubber raw rubber, 2-8 parts of perfluoropolyether additives, 10-25 parts of surface-modified rare earth fluorides, 3-10 parts of surface-modified fumed silica, 0.5-6 parts of peroxide vulcanizing agent, 1-8 parts of co-vulcanizing agent, and 0.1-3 parts of vulcanization accelerator; Step 2: Mix a portion of the fluororubber raw rubber with perfluoropolyether additives and knead to obtain masterbatch; Step 3: Add the remaining portion of the fluororubber raw rubber to the masterbatch, mix, and then add surface-modified rare earth fluorides to mix again to obtain the first compound. Step 4: Add surface-modified fumed silica to the first compound and mix to obtain the second compound. Step 5: Add peroxide vulcanizing agent, co-vulcanizing agent and vulcanization accelerator to the second compound in sequence, and mix to obtain the compound; Step 6: Perform a single vulcanization on the compounded rubber to obtain a single-vulcanized product; Step 7: Perform a second vulcanization on the product after primary vulcanization to obtain a fluororubber material resistant to plasma corrosion.

2. The method for preparing a plasma-resistant fluororubber material according to claim 1, characterized in that, In step one: the fluororubber raw rubber includes a terpolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene; The Mooney viscosity ML(1+10)121℃ of the vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer is 20-40.

3. The method for preparing a plasma-resistant fluororubber material according to claim 1, characterized in that, In step one: the perfluoropolyether additive includes at least one of perfluoropolyether carboxylic acid and polyhexafluoropropylene oxide monoethanol.

4. The method for preparing a plasma-resistant fluororubber material according to claim 1, characterized in that, In step one: the surface-modified rare earth fluorides include coupling agent-modified rare earth fluorides; The coupling agent includes an aluminate coupling agent; The rare earth fluorides include yttrium fluoride.

5. The method for preparing a plasma-resistant fluororubber material according to claim 1, characterized in that, In step one: the surface-modified fumed silica includes fluorosilane coupling agent-modified fumed silica; The fluorosilane coupling agent includes tridecafluorooctyltriethoxysilane.

6. The method for preparing a plasma-resistant fluororubber material according to claim 1, characterized in that, In step one: the peroxide vulcanizing agent includes any one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide, and tert-butyl peroxide; the co-vulcanizing agent includes triallyl isocyanurate; and the vulcanization accelerator includes at least one of N,N'-m-phenylene bismaleimide, zinc dimethacrylate, and magnesium methacrylate.

7. The method for preparing a plasma-resistant fluororubber material according to claim 1, characterized in that, In step two: a portion of the fluororubber raw rubber accounts for 15%-45% of the total mass of the fluororubber raw rubber, and the mixing conditions are mixing at 30-50℃ for 4-8 minutes; In step three: the mixing conditions are mixing at 30-50℃ for 3-5 minutes, and the surface-modified rare earth fluorides are added in batches, with each batch of surface-modified rare earth fluorides added and then mixed at 30-50℃ for 2-4 minutes; In step four: the mixing conditions are mixing at 30-50℃ for 4-8 minutes; In step five: the mixing conditions are mixing at 30-50℃ for 3-6 minutes.

8. The method for preparing a plasma-resistant fluororubber material according to claim 1, characterized in that, In step six: the first vulcanization is carried out at a temperature of 160-180℃ and a pressure of 5-25MPa, and the vulcanization time is 8-30min; In step seven: the secondary vulcanization is carried out at a temperature of 200-250℃ for 8-24 hours; The heating rate for secondary vulcanization is 0.3-1.5℃ / min.

9. A fluororubber material resistant to plasma corrosion, characterized in that, The plasma-resistant fluororubber material is prepared using the preparation method described in any one of claims 1-8.

10. The application of the plasma-resistant fluororubber material as described in claim 9 in semiconductor devices.

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