Perfluoroether rubber valve plate and preparation method thereof

Abstract

The invention discloses a preparation method of a perfluoroether rubber valve plate, which comprises the following steps: step 1, sequentially carrying out nickel plating, sand blasting and plasma etching treatment on the surface of an aluminum alloy matrix to obtain a pretreated aluminum alloy part; 2, the pretreated aluminum alloy part and perfluoroether rubber are placed in a mold, compression molding is carried out under the condition that no chemical adhesive exists, the valve plate obtained after compression molding is obtained, and vacuum is adopted for assisting exhausting in the compression molding process; and step 3, performing high-temperature secondary vulcanization treatment on the valve plate subjected to compression molding to obtain the perfluoroether rubber valve plate. The perfluoroether rubber valve plate provided by the invention has excellent chemical corrosion resistance, high-temperature stability and sealing performance, and the problems of pollution, aging and failure caused by a traditional adhesive are effectively solved. According to the preparation method, the production process is simplified, the environmental risk is reduced, and an efficient solution is provided for key components of semiconductor equipment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perfluoroether rubber sealing, and particularly relates to a perfluoroether rubber valve plate and a preparation method thereof. BACKGROUND

[0002] As a high-performance elastomer material, perfluoroether rubber (FFKM) has been widely used in the fields of semiconductor, chemical industry, aerospace, etc. due to its excellent chemical corrosion resistance, high temperature resistance and excellent sealing performance. In the semiconductor manufacturing process, there are many types of vacuum valve plates, which are composed of a metal substrate and an adhered rubber, and are key sealing components of core parts such as etching and deposition equipment, and work in a strong corrosive medium (such as Cl2, NF3 plasma), extreme temperature (-20 ℃ to 300 ℃) and high vacuum environment for a long time.

[0003] In the traditional technology, the combination of perfluoroether rubber and metal substrate (such as aluminum alloy) usually depends on chemical adhesives. However, this method exposes significant defects in the harsh environment of semiconductor manufacturing:

[0004] 1. Risk of organic contamination: the adhesive is prone to decomposition and volatilization under high temperature or plasma environment, releasing organic impurities and polluting the wafer surface, affecting the yield and performance of semiconductor devices.

[0005] 2. Interface aging and failure: the chemical adhesive itself has limited corrosion resistance and is prone to degradation when exposed to strong corrosive media for a long time, leading to peeling of the adhesive 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 process steps of multi-layer adhesives are cumbersome and require high precision, which not only reduces production efficiency and yield, but also increases production costs.

[0007] 4. Insufficient adhesion strength: the adhesion strength of traditional adhesives under the combined action of high temperature and chemical corrosion is often difficult to meet the requirements of long-term stable operation, limiting the service life of the valve plate. SUMMARY

[0008] Developing a valve plate preparation method that does not require chemical adhesives and can achieve high-strength and high-reliability bonding of perfluoroether rubber and metal substrate is of great significance for improving the performance of semiconductor manufacturing equipment, reducing costs, and reducing cavity pollution.

[0009] In a first aspect, the application provides a preparation method of a perfluoroether rubber valve plate, comprising the following steps:

[0010] Step 1, sequentially carrying out nickel plating, sand blasting and plasma etching treatment on the surface of the aluminum alloy base to obtain a pretreated aluminum alloy piece;

[0011] Step 2, placing the pretreated aluminum alloy piece and perfluoroether rubber in a mold to be molded under the condition of no chemical adhesive to obtain a molded valve plate, wherein a vacuum assisted exhaust is used in the molding process.

[0012] Step 3, carrying out 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, the sand blasting uses aluminum oxide particles with a particle size of 80-120 mesh, and the surface roughness Ra value is controlled to be 1.5-2.0 μm.

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

[0016] In one embodiment, the mixed gas includes CF4 and O2 mixed gas or NF3 and O2 mixed gas, 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 secondary vulcanization temperature is 200-240 ℃, and the time is 14-18 h.

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

[0020] The second aspect of the application provides a perfluoroether rubber valve plate prepared by the above method, the interfacial bonding strength between the pretreated aluminum alloy base and the rubber layer is greater than the thermal stress caused by the mismatch of the thermal expansion coefficients of the materials; the vacuum sealing leakage rate is <10 -8 Pa·m 3 / s.

[0021] In a third aspect, the application provides the full-fluoroether rubber valve plate as described above for use in a vacuum valve or gas control system of a semiconductor manufacturing equipment as a sealing assembly of an etching chamber or a chemical vapor deposition chamber.

[0022] Compared with the prior art, the application has the following remarkable beneficial effects:

[0023] Eliminate pollution risk: through the synergistic effect of multi-step surface treatment, the dependence on chemical adhesives is fundamentally eliminated, organic volatile pollution is avoided, and the cleanliness of the semiconductor manufacturing environment is improved.

[0024] Improve bonding strength and durability: sandblasting provides mechanical anchoring, nickel plating and plasma fluorination treatment improve chemical affinity, and secondary vulcanization effectively solve the problem of easy peeling at the interface, prolonging the service life.

[0025] Excellent corrosion resistance and thermal stability: the adhesive-free design avoids weak links, combined with the excellent performance of the full-fluoroether rubber itself, the valve plate can work stably in a strong corrosion and high temperature environment for a long time.

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

[0027] Simplify the process and reduce the cost: eliminate the adhesive coating and curing steps, simplify the process, improve production efficiency and yield, and reduce cost and environmental risk.

[0028] Strong adaptability and adjustability: suitable for aluminum alloy substrates of different structures, and can be adjusted by adjusting the rubber formula and process parameters to adapt to the specific needs of different semiconductor processes. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings obtained from these drawings without creative labor still belong to the scope of the application.

[0030] Figure 1 It is a process flow diagram of the adhesive-free molding full-fluoroether rubber valve plate preparation method of the application. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present application will be described in detail below with reference to the drawings, so as to make the objects, features and advantages of the present application more clearly understood. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present application, but merely to illustrate the essential spirit of the technical solutions of the present application.

[0032] In the following description, for the purposes of explaining the various disclosed embodiments, some specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. However, one skilled in the relevant art will recognize that the embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, and techniques associated with the present application are not shown or described in order to avoid unnecessarily obscuring the description of the embodiments.

[0033] Reference throughout this specification to "an embodiment" or "the embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0034] In the following description, for the purposes of explaining the present application, certain directional terms are used, such as forward, rearward, left, right, outward, inward, upward, downward, etc. However, it should be understood that these directional terms are used for the convenience of the specification only and do not intend to limit the scope of the present application.

[0035] It should be noted that the features shown in the drawings of the present application can belong to one embodiment or to different embodiments, as long as there is no mutual conflict between these features. In order to save space, the present application can use the same drawing to describe different embodiments, that is, the same drawing of the present application can be used to embody the features in different embodiments.

[0036] The present application provides a preparation method of an adhesive-free compression molded full-fluoroether rubber valve plate, as shown in the flowchart, which shows the core steps of the preparation method of the present application. Starting from providing an aluminum alloy substrate, a plurality of surface pretreatments including nickel plating, sandblasting, and plasma etching are sequentially performed; at the same time, a triazine full-fluoroether rubber green rubber sheet is prepared. Subsequently, the pretreated substrate and the rubber are subjected to adhesive-free compression molding in a mold. Finally, the compression molded body is subjected to high-temperature secondary vulcanization treatment, and finally a high-performance finished valve plate is obtained. Figure 1 In a first aspect, the present application provides a preparation method of a full-fluoroether rubber valve plate, comprising the following steps:

[0037]

[0038] ​Step one, surface pretreatment of aluminum alloy substrate: sequentially performing nickel plating treatment on the aluminum alloy substrate to form a metal coating, sand blasting process to increase surface roughness, fluorine-containing gas plasma etching to generate a fluorinated layer; obtaining the pretreated aluminum alloy substrate.

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

[0040] In one embodiment, the sand blasting process in step one uses aluminum oxide sand particles with a particle size of 80-120 mesh (0.178 mm -0.125 mm), and the roughness Ra value of the treated aluminum alloy substrate forming surface is controlled at 1.5-2.0 μm.

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

[0042] In one embodiment, the mixed gas includes CF4 and O2 mixed gas or NF3 and O2 mixed gas, 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 two, binderless die forming: placing the pretreated aluminum alloy substrate and perfluoroether rubber green sheet together in a mold, and performing die forming without chemical adhesive, and the die forming process uses vacuum assisted exhaust.

[0044] In one embodiment, the process parameters of the die forming in step two are temperature 180-200 ℃, pressure 15-20 MPa, and time 10-15 min; the vacuum degree of the vacuum assisted exhaust is less than 10 -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 of the thermal expansion coefficients between the materials, ensuring the adhesion effect.

[0046] The thermal stress caused by the mismatch of the thermal expansion coefficients between the materials is

[0047]

[0048] In the formula, S is the thermal stress (MPa), E(T) is the elastic modulus of the perfluoroether rubber (MPa), is the difference between the linear expansion coefficients (CTE) of the perfluoroether rubber and the aluminum alloy (1 / ℃). For a unit length of perfluoroether elastomer and aluminum alloy parts, assuming that the elastic modulus E(T) of the perfluoroether rubber and the linear expansion coefficients of different materials are constants, the above formula is simplified as

[0049]

[0050] linear expansion coefficient of the perfluoroether elastomer, linear expansion coefficient of the aluminum alloy material, difference between the highest working temperature of the valve plate and the ambient temperature.

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

[0052] In one embodiment, the perfluoroether rubber comprises a corrosion-resistant filler in the raw rubber formula, the corrosion-resistant filler being at least one of polytetrafluoroethylene micro powder, perfluoroalkoxy alkane micro powder or polyimide micro powder; the micro powder content is 0-15wt%.

[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 three, high-temperature secondary vulcanization treatment to obtain a perfluoroether rubber valve plate.

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

[0056] In a second aspect, the present application provides an adhesive-free compression molded perfluoroether rubber valve plate prepared by the above method.

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

[0058] In a third aspect, the present application provides the use of the above adhesive-free compression molded perfluoroether rubber valve plate in semiconductor manufacturing equipment.

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

[0060] Example 1

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

[0062] Preparation steps

[0063] Step 1, substrate pretreatment

[0064] 6061 aluminum alloy substrate forming surface is smooth surface (5.5 mm wide) electroless nickel (phosphorus-containing nickel), thickness 8±0.5 μm; wherein, the 6061 aluminum alloy substrate length x width x height is 342 mm x 55.9 mm x 26.2 mm;

[0065] Alumina sand (about 100 mesh / 0.152 mm) sandblasting, Ra=1.8 μm;

[0066] CF4 / O2 mixed gas (3.5:1) plasma etching 1400 s, generating a nickel fluoride (NiF2) active layer.

[0067] Step 2, compression molding

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

[0069] Vacuum exhaust and compression molding: 190 ℃ / 18 MPa / 12 min.

[0070] Step 3, secondary vulcanization

[0071] Programmed to 220 ℃ and kept for 16 h.

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

[0073] Performance verification

[0074]

[0075] GB / T 11211-2009 Determination of the Adhesion Strength of Vulcanized or Thermoplastic Rubber to Metal Two-Plate Method.

[0076] Example 2

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

[0078] The preparation steps are basically the same as in Example 1, with some process optimizations:

[0079] In Step 1, etching reinforcement: etch with NF3 / O2 mixed gas (2.5:1) for 1500 s;

[0080] In Step 2, rubber formulation: add 10% PFA powder to triazine perfluoroether rubber to improve plasma erosion resistance;

[0081] In Step 3, vulcanization parameters: program temperature to 240°C and maintain for 14 h to accelerate crosslinking.

[0082] Key performance tests:

[0083] After 200 h of continuous impact by NF3 plasma (500 W), the mass loss of the rubber layer is <0.8% (control group >3.2%);

[0084] In a 150°C / 95% humidity environment, there is no electrochemical corrosion at the metal-rubber interface.

[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, with some process optimizations:

[0088] In Step 1, fine control of sandblasting: about 120 mesh aluminum oxide (0.125 mm), Ra=1.5 μm;

[0089] In Step 2, vacuum degree during molding stage <10 -2 Pa, to eliminate micro-bubbles;

[0090] In Step 3, after secondary vulcanization, helium mass spectrometry leak detection, leakage rate is 2.3×10 -9 Pa·m 3 / s.

[0091] Example 4

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

[0093] The preparation steps are basically the same as in Example 1, with some process optimizations:

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

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

[0096] Step 3, two-step vulcanization: pre-crosslinking at 180 °C / 10 h, and then deep vulcanization at 220 °C / 8 h.

[0097] Extreme environment test

[0098] -20 °C cold start test: the sealing torque only decreases by 12% (decreases by 25% for traditional bonded valve plate);

[0099] -50 °C-250 °C alternating temperature impact (200 times), and the interface is free of cracks.

[0100] Technical advantage: breakthrough in low-temperature environment sealing failure bottleneck.

[0101] The above embodiments are merely preferred embodiments of the present application, and are not intended to limit the present application, and the protection scope of the present application is defined by the appended claims. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

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

[0103] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application.

[0104] It should be noted that, in this document, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, or module that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, system, or module. Without more limitations, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, system, or module that includes the element.

[0105] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and it is intended to embrace all such modifications and changes that fall within the scope of the application. Accordingly, the application is not to be restricted in scope to the specific embodiments disclosed herein but is to be accorded the full scope that the principles and novel features request appropriately granted.

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; Step 2, placing the pretreated aluminum alloy part and perfluoroether rubber in a mold to be molded under the condition of no chemical adhesive to obtain a molded valve plate, wherein a vacuum assisted exhaust is used in the molding process; Step 3, performing high temperature secondary vulcanization treatment on the molded valve plate to obtain a perfluoroether 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 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 plasma etching first uses O2 etching, and then uses mixed gas etching, and the etching time is 1200-1500 s.

5. The preparation method according to claim 4, characterized in that, The mixed gas includes a mixed gas of CF4 and O2 or a mixed gas 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.

6. The method of claim 1, wherein, In step 2, the molding parameters are as follows: 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 perfluoroether rubber contains a corrosion-resistant filler, the content of the corrosion-resistant filler is 0-15 wt%, and the corrosion-resistant filler is 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, it is applied in a vacuum valve or a gas control system of a semiconductor manufacturing equipment.

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