Perfluoroether rubber valve plate and method of making

Abstract

The application discloses a kind of preparation methods of perfluoroether rubber valve plate, comprising the following steps: step 1, the surface of aluminum alloy matrix is successively plated nickel, sandblasting and plasma etching treatment, obtain pretreated aluminum alloy parts;Step 2, the pretreated aluminum alloy parts and perfluoroether rubber are placed in mould, and are molded under the condition of no chemical adhesive, obtain the valve plate after molding, wherein, vacuum assisted exhaust is used in the molding process;Step 3, the valve plate after molding is carried out high temperature secondary vulcanization treatment, and obtains perfluoroether rubber valve plate.The perfluoroether rubber valve plate provided by the application has excellent chemical corrosion resistance, high temperature stability and sealing performance, effectively solves the pollution, aging and failure problem caused by traditional adhesive.The preparation method of the application simplifies the production process, reduces the environmental risk, and provides an efficient solution for the key components of semiconductor equipment.

Description

Technical Field

[0001] This invention belongs to the field of perfluoroether rubber sealing technology, specifically relating to a perfluoroether rubber valve plate and its preparation method. Background Technology

[0002] Perfluoroelastomer (FFKM), as a high-performance elastomer material, is widely used in fields with extremely demanding material performance requirements, such as semiconductors, chemicals, and aerospace, due to its excellent chemical corrosion resistance, high temperature resistance, and superior sealing performance. In semiconductor manufacturing processes, vacuum valve plates come in many types, consisting of a metal substrate and adhered rubber. They are key sealing components in core parts such as etching and deposition equipment, operating for extended periods in highly corrosive media (such as Cl2 and NF3 plasma), extreme temperatures (-20 ℃ to 300 ℃), and high vacuum environments.

[0003] In traditional techniques, the bonding of perfluoroelastomers to metal substrates (such as aluminum alloys) typically relies on chemical adhesives. However, this method exhibits significant drawbacks in the harsh environments of semiconductor manufacturing:

[0004] 1. Organic pollution risk: The adhesive is prone to decomposition and volatilization in high temperature or plasma environment, releasing organic impurities, which contaminate the wafer surface and affect the yield and performance of semiconductor devices.

[0005] 2. Interface aging and failure: Chemical adhesives themselves have limited corrosion resistance. Long-term exposure to strong corrosive media can easily lead to degradation, resulting in peeling of the bonding interface, a sharp decline in sealing performance, excessive leakage rate, and increased equipment maintenance costs and downtime.

[0006] 3. Process complexity and cost: The coating and curing processes of multi-layer adhesives are complicated and require high operational precision, which not only reduces production efficiency and yield but also increases production costs.

[0007] 4. Insufficient adhesive strength: Under the combined effects of high temperature and chemical corrosion, the adhesive strength of traditional adhesives is often insufficient to meet the requirements of long-term stable operation, which limits the service life of the valve plate. Summary of the Invention

[0008] Developing a valve plate preparation method that achieves high-strength and high-reliability bonding between perfluoroether rubber and metal matrix without chemical adhesives is of vital importance for improving the performance of semiconductor manufacturing equipment, reducing costs, and minimizing cavity contamination.

[0009] In a first aspect, the present invention provides a method for preparing a perfluoroether rubber valve plate, comprising the following steps:

[0010] Step 1: Perform nickel plating, sandblasting and plasma etching on the surface of the aluminum alloy substrate in sequence to obtain the pretreated aluminum alloy part.

[0011] Step 2: Place the pretreated aluminum alloy parts and perfluoroether rubber in a mold and mold them without chemical adhesives to obtain the molded valve plate. Vacuum-assisted degassing is used in the molding process.

[0012] Step 3: Perform a high-temperature secondary vulcanization treatment on the molded valve plate to obtain a perfluoroether rubber valve plate.

[0013] In one embodiment, in step 1, the thickness of the nickel plating layer is 5-20 μm.

[0014] In one embodiment, in step 1, alumina sand with a particle size of 80-120 mesh is used for sandblasting, and the surface roughness Ra value is controlled at 1.5-2.0 μm.

[0015] In one embodiment, in step 1, plasma etching first uses O2 etching, then uses mixed gas etching, and the etching time is 1200-1500 s.

[0016] In one embodiment, the mixed gas includes a mixture of CF4 and O2 or a mixture of NF3 and O2, wherein the volume ratio of CF4 to O2 is 3-5:1 and the volume ratio of NF3 to O2 is 2-4:1.

[0017] In one embodiment, in step 2, the molding parameters are: temperature 180-200 ℃, pressure 15-20 MPa, and time 10-15 min.

[0018] In one embodiment, in step 3, the temperature of the secondary vulcanization is 200-240 °C, and the time is 14-18 h.

[0019] In one embodiment, the raw rubber formulation of the perfluoroether rubber contains a corrosion-resistant filler, the content of which is 0-15 wt%, and the corrosion-resistant filler is at least one of polytetrafluoroethylene micro powder, perfluoroalkoxyalkane micro powder, or polyimide micro powder.

[0020] In a second aspect, the present invention provides a perfluoroether rubber valve plate prepared by the above method, wherein the bonding strength between the aluminum alloy substrate and the rubber layer after pretreatment is greater than the thermal stress caused by the mismatch of the thermal expansion coefficients between the materials; and the vacuum sealing leakage rate is <10%. -8 Pa·m 3 / s.

[0021] A third aspect of the present invention provides the above-described perfluoroether rubber valve plate as a sealing component for etching chambers or chemical vapor deposition chambers, and its application in vacuum valves or gas control systems of semiconductor manufacturing equipment.

[0022] Compared with the prior art, the present invention has the following significant advantages:

[0023] Eliminating pollution risks: Through the synergistic effect of multi-step surface treatment, the dependence on chemical adhesives is fundamentally eliminated, avoiding volatile organic compound pollution and improving the cleanliness of the semiconductor manufacturing environment.

[0024] Improved bonding strength and durability: Sandblasting provides mechanical anchoring, nickel plating and plasma fluorination enhance chemical affinity, and secondary vulcanization effectively solves the problem of easy peeling at the interface and extends service life.

[0025] Excellent corrosion resistance and thermal stability: The adhesive-free design avoids weak points, and combined with the excellent properties of perfluoroelastomer rubber itself, the valve plate can work stably for a long time in highly corrosive and high-temperature environments.

[0026] Excellent sealing performance: Vacuum-assisted molding and secondary vulcanization ensure a defect-free interface; the bonding strength between the aluminum alloy substrate and the perfluoroether rubber layer is greater than the thermal stress caused by the mismatch in the coefficients of thermal expansion between the materials; the helium leakage rate can be stably controlled within 10%. -8 Pa·m 3 With speeds below / s, high reliability of equipment operation is ensured.

[0027] Simplified process and reduced costs: Eliminating the adhesive coating and curing steps simplifies the process, improves production efficiency and yield, and reduces costs and environmental risks.

[0028] Strong adaptability and adjustability: It is suitable for aluminum alloy substrates with different structures, and can be adapted to the specific needs of different semiconductor processes by adjusting the rubber formulation and process parameters. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0030] Figure 1 This is a schematic diagram of the process flow for the preparation method of the adhesive-free compression molding perfluoroether rubber valve plate of the present invention. Detailed Implementation

[0031] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to better understand the purpose, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are only for illustrating the essential spirit of the technical solution of the present invention.

[0032] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the art will recognize that the embodiments can be practiced without one or more of these specific details. In other instances, well-known apparatuses, structures, and techniques associated with this application may not have been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0033] Throughout this specification, references to "one embodiment" or "one embodiment" indicate that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Therefore, the appearance of "one embodiment" or "one embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0034] In the following description, in order to clearly demonstrate the structure and operation of the present invention, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and not as limiting terms.

[0035] It should be noted that the features shown in the accompanying drawings of this application may belong to one embodiment or different embodiments, as long as there is no conflict between these features. To save space, this application may use the same drawing to illustrate different embodiments; that is, the same drawing of this application may be used to illustrate features in different embodiments.

[0036] This invention provides a method for preparing a binder-free, compression-molded perfluoroether rubber valve plate, such as... Figure 1 As shown in the flowchart, this process illustrates the core steps of the preparation method of this invention. Starting with an aluminum alloy substrate, a multi-step surface pretreatment process is performed, including nickel plating, sandblasting, and plasma etching; simultaneously, a triazine-based perfluoroether rubber raw sheet is prepared. Subsequently, the pretreated substrate and rubber are molded together in a mold without adhesive. Finally, the molded body undergoes a high-temperature secondary vulcanization treatment to obtain a high-performance finished valve plate.

[0037] In a first aspect, the present invention provides a method for preparing a perfluoroether rubber valve plate, comprising the following steps:

[0038] Step 1: Surface pretreatment of aluminum alloy substrate: The aluminum alloy substrate is subjected to nickel plating to form a metal coating, sandblasting to increase surface roughness, and fluorine-containing gas plasma etching to generate a fluorinated layer; thus obtaining the pretreated aluminum alloy substrate.

[0039] In one embodiment, the nickel plating process in step one is electroless nickel plating, and the thickness of the nickel plating layer formed is 5-20 μm.

[0040] In one embodiment, the sandblasting process in step one uses alumina sand with a particle size of 80-120 mesh (0.178 mm - 0.125 mm), and the roughness Ra value of the formed working surface of the aluminum alloy substrate after treatment is controlled at 1.5-2.0 μm.

[0041] In one embodiment, in step one, plasma etching first uses O2 etching, then uses mixed gas etching, and the plasma etching time is 1200-1500 s.

[0042] In one embodiment, the mixed gas includes a mixture of CF4 and O2 or a mixture of NF3 and O2, wherein the volume ratio of CF4 to O2 is 3-5:1 and the volume ratio of NF3 to O2 is 2-4:1.

[0043] Step 2, Adhesive-free compression molding: The pretreated aluminum alloy substrate and the perfluoroether rubber raw sheet are placed together in the mold and compression molded without chemical adhesives. Vacuum-assisted degassing is used in the compression molding process.

[0044] In one embodiment, the molding process parameters in step two are: temperature 180-200℃, pressure 15-20 MPa, and time 10-15 min; the vacuum degree of the vacuum-assisted degassing is less than 10 MPa. -2 Pa.

[0045] In one embodiment, the bonding strength between the aluminum alloy substrate and the perfluoroether rubber layer is greater than the thermal stress caused by the mismatch in the coefficients of thermal expansion between the materials, thus ensuring the bonding effect.

[0046] Thermal stress caused by the mismatch in the coefficients of thermal expansion between materials

[0047]

[0048] In the formula, S is the thermal stress (MPa), and E(T) is the elastic modulus of perfluoroether rubber (MPa). Let be the difference in linear expansion coefficient (CTE) between perfluoroether rubber and aluminum alloy (1 / ℃). For a unit length of perfluoroether elastomer and aluminum alloy component, assuming the elastic modulus E(T) of perfluoroether rubber and the linear expansion coefficients of different materials are constants, the above formula simplifies to:

[0049]

[0050] The linear expansion coefficient of perfluoroether elastomers. The linear expansion coefficient of aluminum alloy materials. This is the difference between the valve plate's maximum operating temperature and the ambient temperature.

[0051] In one embodiment, the perfluoroether rubber includes a peroxide system or a triazine system, preferably a triazine-based perfluoroether rubber.

[0052] In one embodiment, the raw rubber formulation of the perfluoroether rubber contains a corrosion-resistant filler, which is at least one of polytetrafluoroethylene micro powder, perfluoroalkoxyalkane micro powder, or polyimide micro powder; the micro powder content is 0-15 wt%.

[0053] In one embodiment, the forming working surface of the aluminum alloy substrate is a smooth surface (roughness Ra value less than 1.0 μm); or the forming working surface of the aluminum alloy substrate is provided with a groove structure for enhancing mechanical interlocking.

[0054] Step 3: High-temperature secondary vulcanization treatment to obtain perfluoroether rubber valve plate.

[0055] In one embodiment, the process conditions for the secondary vulcanization treatment in step three are: a temperature of 200-240 °C for 14-18 h.

[0056] In a second aspect, the present invention provides a binder-free molded perfluoroether rubber valve plate prepared by the above method.

[0057] In one embodiment, the bonding strength between the aluminum alloy substrate of the valve plate and the perfluoroether rubber layer is greater than the thermal stress caused by the mismatch in the coefficients of thermal expansion between the materials, ensuring a good bonding effect; the vacuum seal leakage rate at room temperature is <10%. -8 Pa·m 3 / s.

[0058] A third aspect of the present invention provides the application of the above-described adhesive-free molded perfluoroether rubber valve plate in semiconductor manufacturing equipment.

[0059] In one embodiment, the application is to use the valve plate as a sealing component in a vacuum valve or gas control system of a semiconductor manufacturing equipment, particularly suitable for etching chambers or chemical vapor deposition chambers.

[0060] Example 1

[0061] Standard process valve plate (for etching chambers)

[0062] Preparation steps

[0063] Step 1: Matrix Pretreatment

[0064] The 6061 aluminum alloy substrate forming working surface is a smooth surface (5.5 mm wide) electroless nickel plating (phosphorus-containing nickel) with a thickness of 8±0.5μm; the 6061 aluminum alloy substrate has a length×width×height of 342 mm×55.9 mm×26.2 mm.

[0065] Alumina sand (approximately 100 mesh / 0.152 mm) was blasted, Ra=1.8μm;

[0066] Plasma etching with a CF4 / O2 mixed gas (3.5:1) for 1400 s produces a nickel fluoride (NiF2) active layer.

[0067] Step 2: Compression molding

[0068] Pretreated matrix and triazine perfluoroether rubber sheet (Shanghai Senhuan Morsz) are stacked in the mold. ® 6880 SP (containing 10% PTFE micro powder); wherein, the triazine perfluoroether rubber sheet is 5.5 mm wide, 3.5 mm high, and 753.5 mm long.

[0069] Vacuum degassing followed by compression molding: 190 ℃ / 18 MPa / 12 min.

[0070] Step 3, Secondary vulcanization

[0071] The temperature was raised to 220 ℃ and held for 16 hours.

[0072] Measurement parameters: Moriz ® The CTE of the 6880SP is 371×10 -6 / ℃; the CTE of the aluminum alloy is 23.6×10 -6 / ℃. For the triazine system, the average elastic modulus E(T) of the perfluoroether rubber is 93.4 MPa, the difference ΔT between the highest operating temperature of the valve plate and the ambient temperature is 105 ℃, and the thermal stress S caused by the mismatch of the thermal expansion coefficients between the materials is about 3.4 MPa.

[0073] Performance verification

[0074]

[0075] GB / T 11211-2009 Determination of the bond strength between vulcanized rubber or thermoplastic rubber and metal - two-plate method.

[0076] Example 2

[0077] High corrosion resistant valve plate (for NF3 cleaning system)

[0078] The preparation steps are basically the same as in Example 1, but some processes have been optimized:

[0079] In step 1, etching enhancement: etching is performed using an NF3 / O2 mixed gas (2.5:1) for 1500 s;

[0080] In step 2, the rubber formulation uses triazine perfluoroether rubber with 10% PFA micro powder added to improve its resistance to plasma erosion.

[0081] In step 3, the vulcanization parameters are: the temperature is programmed to rise to 240 ℃ and held at that temperature for 14 h to accelerate crosslinking.

[0082] Key performance tests:

[0083] After continuous NF3 plasma (500 W) impact for 200 h, the mass loss of the rubber layer was <0.8% (compared to >3.2% in the control group).

[0084] No electrochemical corrosion was observed at the metal-rubber interface in an environment of 150 °C / 95% humidity.

[0085] Example 3

[0086] Ultra-low leakage valve plate (for CVD gas delivery)

[0087] The preparation steps are basically the same as in Example 1, but some processes have been optimized:

[0088] In step 1, the sandblasting is finely controlled: approximately 120 mesh alumina (0.125 mm), Ra=1.5μm;

[0089] In step 2, the vacuum level during the molding stage is <10. -2 Pa, eliminates microbubbles;

[0090] In step 3, after secondary sulfidation, helium mass spectrometry leak detection was performed, and the leak rate was 2.3 × 10⁻⁶. -9 Pa·m 3 / s.

[0091] Example 4

[0092] Wide temperature range valve plate (improved low temperature adaptability)

[0093] The preparation steps are basically the same as in Example 1, but some processes have been optimized:

[0094] In step 1, interface strengthening: the nickel plating layer is thickened to 10μm to compensate for the low-temperature metal shrinkage stress;

[0095] In step 2, the rubber formulation: the FFKM plasticizer content is increased by 8%, and the glass transition temperature (Tg) is reduced to -35 ℃;

[0096] In step 3, there is a two-step vulcanization process: first, pre-crosslinking at 180 ℃ for 10 h, and then deep vulcanization at 220 ℃ for 8 h.

[0097] Extreme environment testing

[0098] -20 ℃ cold start test: sealing torque decreased by only 12% (compared to 25% for traditional adhesive valve plates);

[0099] The bonding interface remained crack-free after 200 cycles of alternating temperature shock from -50℃ to 250℃.

[0100] Technical advantages: Overcoming the bottleneck of sealing failure in low-temperature environments.

[0101] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is determined by the appended claims. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0102] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0103] Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the invention.

[0104] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, system, or module that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, system, or module. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, system, or module that includes said element.

[0105] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A method of making a perfluoroether rubber valve plate, characterized by, The method comprises the following steps: Step 1, sequentially performing nickel plating, sand blasting and plasma etching treatment on the surface of an aluminum alloy base to obtain a pretreated aluminum alloy part, wherein the plasma etching is first performed using O2 etching, and then using mixed gas etching, the mixed gas comprising CF4 and O2 mixed gas or NF3 and O2 mixed gas, the volume ratio of CF4 to O2 being 3-5:1; Step 2, placing the pretreated aluminum alloy part and perfluoro ether rubber in a mold to be molded under the condition of no chemical adhesive to obtain a molded valve plate, wherein the molding process adopts vacuum assisted exhaust; Step 3, performing high temperature secondary vulcanization treatment on the molded valve plate to obtain a perfluoro ether rubber valve plate.

2. The production method according to claim 1, characterized by, In step 1, the thickness of the nickel plating layer is 5-20 μm.

3. The preparation method according to claim 1, characterized in that, In step 1, the sand blasting uses aluminum oxide sand particles with a particle size of 80-120 mesh, and the surface roughness Ra value is controlled to be 1.5-2.0 μm.

4. The method of claim 1, wherein, In step 1, the etching time is 1200-1500 s.

5. The preparation method according to claim 4, characterized in that, The volume ratio of NF3 to O2 is 2-4:

1.

6. The method of claim 1, wherein, In step 2, the molding parameters are: temperature 180-200 ℃, pressure 15-20 MPa, and time 10-15 min.

7. The preparation method according to claim 1, characterized in that, In step 3, the secondary vulcanization temperature is 200-240 ℃, and the time is 14-18 h.

8. The production method according to any one of claims 1 to 7, characterized by, The raw rubber formula of the perfluoro ether rubber contains a corrosion-resistant filler, the content of the corrosion-resistant filler being 0-15 wt%, and the corrosion-resistant filler being at least one of polytetrafluoroethylene micro powder, perfluoroalkoxy alkane micro powder or polyimide micro powder.

9. A perfluoroether rubber valve plate prepared by the method of any one of claims 1-8, characterized by, The interfacial bonding strength between the pretreated aluminum alloy substrate and the rubber layer is greater than the thermal stress caused by the mismatch of the thermal expansion coefficients between the materials; the vacuum sealing leakage rate is less than 10 -8 Pa·m 3 / s.

10. A perfluoroelastomer valve plate according to claim 9, characterized in that, As a sealing assembly of an etching chamber or a chemical vapor deposition chamber, the application is used in a vacuum valve or a gas control system of a semiconductor manufacturing equipment.

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