Preparation method of ETFE film for semiconductor packaging

Abstract

The invention belongs to the technical field of ETFE thin film preparation, and particularly relates to a preparation method of an ETFE thin film for semiconductor packaging. The invention relates to a preparation method of an ETFE film for semiconductor packaging. The preparation method comprises the following steps: (1) preparing a tetrafluoroethylene-glycidyl methacrylate copolymer; (2) pretreating the ETFE resin; (3) carrying out silanization treatment on the nano composite filler; (4) preparing an ETFE film; and (5) carrying out post-treatment on the ETFE film to prepare the ETFE film for semiconductor packaging. The ETFE film for semiconductor packaging, prepared by the preparation method disclosed by the invention, has excellent mechanical properties and wear resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ETFE film preparation, and particularly relates to a preparation method of ETFE film for semiconductor packaging. BACKGROUND

[0002] Film materials commonly used in the field of semiconductor packaging include organic silicon coating film, ordinary polyester film, PTFE film and ETFE film. However, the organic silicon coating film has defects such as silicon migration risk, insufficient heat resistance, easy deformation and short service life. The ordinary polyester film has poor heat resistance, a large coefficient of thermal expansion, easy adhesion to packaging materials and is not suitable for high-temperature processes. The PTFE film has poor processability, difficulty in controlling thickness uniformity and poor adhesion to molds.

[0003] ETFE film gradually emerges in the field of semiconductor packaging due to its high thermal stability, ultra-low surface energy, mechanical properties, chemical inertness and electrical insulation. ETFE film is applied to packaging substrates, isolation layers, sealing materials and protective layers in semiconductor packaging. Related technologies include film forming, cutting, assembling and packaging processes. ETFE film can be used as a film material for semiconductor packaging film. Improving the wear resistance and scratch resistance of ETFE film can improve the performance and reliability of semiconductor devices. For example, additives or fillers with higher wear resistance, such as nanoparticles and carbon nanotubes, can be introduced. Surface treatment technologies such as plasma treatment and chemical modification can also be used to improve the chemical properties and morphology of the ETFE film surface. Nanotechnology can be used to prepare ETFE film with special surface structures, such as nanostructured surfaces and nanoporous structures. These studies can help solve the friction and scratch problems that semiconductor devices may encounter in practical applications, and promote the sustainable development and progress of the semiconductor industry.

[0004] Currently, ETFE film used in the field of semiconductor packaging still has insufficient strength and wear resistance, which is difficult to meet the dual requirements of high cleanliness and high wear resistance for packaging processes. Although SiO2 or carbon nanotubes are added as fillers to improve the performance of ETFE, there are still problems such as filler agglomeration due to low surface energy, no chemical bonding at the interface, and surface migration failure after high-temperature treatment. Therefore, it is necessary to explore a new ETFE film for semiconductor packaging. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of ETFE film for semiconductor packaging. The ETFE film prepared by the method has good tensile strength and wear resistance.

[0006] The preparation method of ETFE film for semiconductor packaging according to the present application comprises the following steps: (1) Preparation of tetrafluoroethylene-glycidyl methacrylate copolymer ① Into a high-pressure reactor, deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium and potassium persulfate were added. After the high-pressure reactor was sealed, the air in the reactor was replaced with nitrogen for 3 times. Then tetrafluoroethylene was introduced into the reactor until the pressure reached 0.2 MPa. The nitrogen was replaced for 2 times, and the reactor was emptied to normal pressure after each replacement. Subsequently, tetrafluoroethylene was continuously introduced into the reactor until the pressure reached 2.5 MPa. Gycidyl methacrylate was introduced into the reactor with nitrogen within 5 min. The reactor was heated to 55-58 ℃ and stirred for reaction. During the reaction, tetrafluoroethylene was continuously added to maintain the pressure in the reactor at 2.5 MPa. When the reaction was carried out for 3 h, methanol was added into the reactor as a polymerization inhibitor. The reaction was stopped after 3.2-3.4 h. The reactor was cooled to room temperature. A tetrafluoroethylene-gycidyl methacrylate copolymer emulsion was prepared. ② The tetrafluoroethylene-gycidyl methacrylate copolymer emulsion was added with a coagulant. The copolymer was precipitated by stirring. After washing and drying, a tetrafluoroethylene-gycidyl methacrylate copolymer was prepared. (2) Pretreatment of ETFE resin The ETFE resin was heated at 150 ℃ in air for 2.5 h and naturally cooled to prepare a pretreated ETFE resin. (3) Silanization treatment of nanocomposite filler ① The halloysite nanotube, nanometer lanthanum fluoride and nanometer zirconium silicate were dissolved in deionized water. Then, ammonia water was added to adjust the pH value of the system to 9.0. The system was ultrasonically treated at 33-35 ℃ for 30 min. ② The 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane solution was added dropwise into the above reaction system. The system was refluxed at 81-83 ℃ for 4 h. Then, the system was filtered, washed, dried and sieved to prepare a silanized nanocomposite filler. (4) The pretreated ETFE resin, the silanized nanocomposite filler and the tetrafluoroethylene-gycidyl methacrylate copolymer were uniformly mixed. Then, the mixture was introduced into a twin-screw extruder for melt blending to obtain a blend. The blend was extruded into a sheet through a T-shaped die. Finally, the ETFE film was prepared by longitudinal stretching, transverse stretching and heat setting. (5) The ETFE film prepared in step (4) was post-treated to prepare an ETFE film for semiconductor packaging.

[0007] In step (1) ①, the mass of 4,8-dioxa-3H-perfluorononanoic acid ammonium accounts for 0.4% of the total mass of deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium, potassium persulfate, tetrafluoroethylene and gycidyl methacrylate.

[0008] In step (1) ①, the mass of potassium persulfate accounts for 0.2-0.23% of the total mass of tetrafluoroethylene and gycidyl methacrylate.

[0009] The total amount of tetrafluoroethylene and the molar ratio of glycidyl methacrylate in step (1) ① are 10-11:1.

[0010] The mass of deionized water in step (1) ① is 3 times the mass of tetrafluoroethylene and glycidyl methacrylate.

[0011] The mass of methanol polymerization inhibitor in step (1) ① is 0.17% of the mass of tetrafluoroethylene and glycidyl methacrylate.

[0012] The coagulant in step (1) ② is a saturated sodium chloride solution, and the volume of the coagulant added is 5% of the volume of the tetrafluoroethylene-glycidyl methacrylate copolymer emulsion.

[0013] The stirring time in step (1) ② is 18-20 min, the washing is washed with deionized water for 3-5 times, and the drying is vacuum dried at 55°C for 10h.

[0014] The mass ratio of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate in step (3) ① is 2:1:2.

[0015] The mass of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate in step (3) ① is 2-3% of the mass of deionized water.

[0016] In step (3) ②, 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane solution is prepared by mixing 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane and anhydrous ethanol in a volume ratio of 1:2, and the dropwise addition rate of 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane solution is 0.7mL / min.

[0017] In step (3) ②, the mass of 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane added in 1H, 1H, 2H, 2H-perfluorodecyl triethoxysilane solution is 5.5% of the mass of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate in step (3) ①.

[0018] In step (3) ②, the washing is washed with deionized water for 3 times and then washed with anhydrous ethanol for 1 time, the drying is vacuum dried at 80°C for 12h, and the sieving is sieved through a 200 mesh sieve.

[0019] In step (3), LaF3 and ZrSiO4 surfaces are first hydrated by a weak base to generate -OH, providing the same reaction site for subsequent covalent grafting, then fluorosilane is condensed with the -OH on the surface of the three fillers, giving the nanofiller low surface energy and enhancing the compatibility with ETFE resin.

[0020] The mixing temperature in step (4) is 60 DEG C, the mixing time is 5 min, and the mixing rotation speed is 300 r / min.

[0021] The ETFE film in step (4) is composed of the following raw materials in parts by weight: pretreated ETFE resin 88-90 parts, silanized nano composite filler 4.5-6.5 parts, and tetrafluoroethylene-glycidyl methacrylate copolymer 3.5-5.5 parts.

[0022] The feeding section temperature of the double screw extruder in step (4) is 256-258 DEG C, the compression section temperature is 272-274 DEG C, the melting section temperature is 278-280 DEG C, the reaction time is 80-85 s, and the screw rotation speed is 190 r / min.

[0023] The double screw extruder in step (4) is provided with a vacuum devolatilization port, which is located at the end of the melting section, and the vacuum degree is -0.09 MPa, which is used for removing residual silane oligomers.

[0024] The longitudinal stretching multiple in step (4) is 3.0-4.0 times, and the longitudinal stretching temperature is 200-205 DEG C.

[0025] The transverse stretching multiple in step (4) is 2.8-3.5 times, and the transverse stretching temperature is 230-235 DEG C.

[0026] The heat setting temperature in step (4) is 175-180 DEG C, the heat setting time is 30-35 s, and the ETFE film is prepared by winding after natural cooling to 50 DEG C.

[0027] The post-treatment in step (5) is that the ETFE film prepared in step (4) is kept at 135-140 DEG C for 3 h, and then naturally cooled to room temperature, so as to eliminate the residual internal stress during extrusion molding, and finally clean cleaning and drying are carried out, so as to prepare the ETFE film for semiconductor packaging, and the clean cleaning and drying include: ① soaking in ultrapure water for 13-15 min, and gently stirring to avoid scratching the film surface, ② ultrasonic cleaning with 0.1% perfluorohexyl ethanol for 5 min, and the ultrasonic power is 130 W, which enhances the impurity stripping without damaging the ETFE; ③ ultrapure water rinsing for 3 times to remove the residual cleaning agent; and ④ vacuum drying at 70-75 DEG C for 1 h to avoid ring opening of the epoxy group caused by high temperature.

[0028] Compared with the prior art, the present application has the following beneficial effects: (1) The preparation method of the ETFE film for semiconductor packaging, in step (1), the tetrafluoroethylene-glycidyl methacrylate copolymer is a fluoropolymer containing an epoxy group, which plays a role of a compatibilizer in the subsequent reaction process, the epoxy group of the glycidyl methacrylate side chain can chemically react with the hydroxyl group of the pretreated ETFE resin in step (2) and the hydroxyl group of the silanized nano-composite filler in step (3) to form a chemical bond, thereby providing a chemical bridging site for the interface bonding between the resin and the filler in step (4), and improving the wear resistance and mechanical properties of the ETFE film. In step (2), the ETFE resin is slightly oxidized to generate hydroxyl groups on the ETFE molecular chain surface, and the hydroxyl groups can bond with the epoxy groups of the tetrafluoroethylene-glycidyl methacrylate copolymer prepared in step (1), so that the compatibilizer is anchored on the ETFE matrix to avoid migration of the compatibilizer. In step (3), the surface of the filler is first made to generate hydroxyl groups in a weak alkali environment, which bond with the epoxy groups of the tetrafluoroethylene-glycidyl methacrylate copolymer, and then the nano-composite filler is grafted with fluorosilane to give the nano-composite filler low surface energy, which matches the low surface energy structure of ETFE to avoid filler agglomeration. The modified filler can be uniformly dispersed in the ETFE matrix in step (4) to form a stable reinforcing system through chemical bonding of 'filler-compatibilizer-ETFE'. In step (4), the pretreated ETFE resin is melted under high temperature and high pressure in a twin-screw extruder, and is fully blended with the silanized nano-composite filler and the tetrafluoroethylene-glycidyl methacrylate copolymer to form complete chemical bonding; longitudinal stretching and transverse stretching make the molecular chain oriented to improve the mechanical strength of the film, and heat setting preliminarily releases internal stress. In step (5), the residual internal stress is eliminated by heat preservation at 135-140 DEG C to improve the dimensional stability of the film, and cleaning removes impurities (residual silane) to improve the cleanliness of the prepared ETFE film.

[0029] (2) The preparation method of the ETFE film for semiconductor packaging, the silanized nano-composite filler selects halloysite nanotubes, nano-fluorinated lanthanum and nano-zirconium silicate for compounding, and the three substances have a synergistic relationship, the halloysite nanotubes have rigidity and toughness, which can disperse stress concentration on one hand and prevent crack propagation on the other hand. The nano-fluorinated lanthanum has relatively high Mohs hardness and low friction coefficient, which can form a wear-resistant layer on the surface of the ETFE film to reduce material loss during friction, and the self-lubricating property can reduce the friction resistance between the film and the contacted object to reduce wear loss. The nano-zirconium silicate has high Mohs hardness and elastic modulus, which can improve the surface rigidity of the film to reduce wear loss and wear depth. The hardness of the three fillers is gradiently distributed from high to low (ZrSiO4>LaF3>HNTs), and when friction occurs, ZrSiO4resists main wear, LaF3reduces friction resistance, and halloysite nanotubes avoid brittle fracture of the film due to excessive rigidity.

[0030] The ETFE film prepared by the preparation method has excellent mechanical properties and wear resistance. DETAILED DESCRIPTION

[0031] Embodiment 1 The preparation method of the ETFE film for semiconductor packaging in this embodiment 1 comprises the following steps: (1) Preparation of tetrafluoroethylene-glycidyl methacrylate copolymer ①Deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium and potassium persulfate were added into a high-pressure reaction kettle, the high-pressure reaction kettle was sealed, the air in the kettle was replaced with nitrogen for 3 times, then tetrafluoroethylene was introduced until the pressure in the kettle reached 0.2 MPa, the nitrogen was replaced for 2 times, and the kettle was emptied to normal pressure after each replacement, then tetrafluoroethylene was continuously introduced until the pressure in the kettle reached 2.5 MPa, glycidyl methacrylate was pressed into the high-pressure reaction kettle with nitrogen within 5 min, the temperature was raised to 56°C for stirring reaction, and tetrafluoroethylene was supplemented during the reaction to maintain the pressure in the kettle at 2.5 MPa; when the reaction was carried out for 3 h, methanol polymerization inhibitor was added into the high-pressure reaction kettle, the heating was stopped when the reaction was carried out for 3.3 h, and the temperature was lowered to room temperature, thereby preparing a tetrafluoroethylene-glycidyl methacrylate copolymer emulsion; ②The tetrafluoroethylene-glycidyl methacrylate copolymer emulsion was added with a coagulant, and the copolymer was precipitated by stirring, and then washed and dried to prepare a tetrafluoroethylene-glycidyl methacrylate copolymer; (2) Pretreatment of ETFE resin The ETFE resin was kept at 150°C in an air atmosphere for 2.5 h, and then naturally cooled to prepare a pretreated ETFE resin; (3) Silanization treatment of nano-composite filler ①The halloysite nanotube, nano-fluorinated lanthanum and nano-zirconium silicate were dissolved in deionized water, then ammonia water was added to adjust the pH value of the system to 9.0, and ultrasonic treatment was carried out at 34°C for 30 min; ②1H,1H,2H,2H-perfluorodecyltriethoxysilane solution was added dropwise into the above reaction system, and reflux reaction was carried out at 82°C for 4 h, then the reaction system was filtered, washed, dried and sieved to prepare a silanized nano-composite filler; (4) The pretreated ETFE resin, the silanized nano-composite filler and the tetrafluoroethylene-glycidyl methacrylate copolymer were uniformly mixed, then were put into a twin-screw extruder for melt blending to obtain a blend, the blend was extruded into a sheet through a T-shaped die, and finally the ETFE film was prepared through longitudinal stretching, transverse stretching and heat setting; (5) The ETFE film prepared in step (4) is post-treated to prepare an ETFE film for semiconductor packaging.

[0032] In step (1) ①, the mass of 4,8-dioxa-3H-perfluorononanoic acid ammonium accounts for 0.4% of the mass sum of deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium, potassium persulfate, tetrafluoroethylene, and glycidyl methacrylate.

[0033] In step (1) ①, the mass of potassium persulfate accounts for 0.21% of the mass sum of tetrafluoroethylene and glycidyl methacrylate.

[0034] In step (1) ①, the total amount of tetrafluoroethylene and the molar ratio of glycidyl methacrylate are 10.5:1.

[0035] In step (1) ①, the mass of deionized water is 3 times the mass sum of tetrafluoroethylene and glycidyl methacrylate.

[0036] In step (1) ①, the mass of methanol polymerization inhibitor accounts for 0.17% of the mass sum of tetrafluoroethylene and glycidyl methacrylate.

[0037] In step (1) ②, the coagulant is a saturated sodium chloride solution, and the volume of the coagulant added is 5% of the volume of the tetrafluoroethylene-glycidyl methacrylate copolymer emulsion.

[0038] In step (1) ②, the stirring time is 19 min, the washing is deionized water washing 4 times, and the drying is vacuum drying at 55°C for 10h.

[0039] In step (3) ①, the mass ratio of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate is 2:1:2.

[0040] In step (3) ①, the mass sum of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate accounts for 2.5% of the mass of deionized water.

[0041] In step (3) ②, 1H,1H,2H,2H-perfluorodecyltriethoxysilane solution is prepared by uniformly mixing 1H,1H,2H,2H-perfluorodecyltriethoxysilane and anhydrous ethanol according to a volume ratio of 1:2, and the dropwise addition rate of 1H,1H,2H,2H-perfluorodecyltriethoxysilane solution is 0.7mL / min.

[0042] In step (3) ②, the mass of 1H,1H,2H,2H-perfluorodecyltriethoxysilane added in 1H,1H,2H,2H-perfluorodecyltriethoxysilane solution accounts for 5.5% of the mass sum of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate in step (3) ①.

[0043] The washing in step (3) ② is washing for 3 times with deionized water and washing for 1 time with anhydrous ethanol, the drying is drying at 80℃ for 12h under vacuum, and the sieving is sieving through a 200 mesh sieve.

[0044] In step (3), firstly, -OH is generated on the surface of LaF3 and ZrSiO4 by weak base hydration, providing the same reaction site for subsequent covalent grafting, and then fluorosilane is condensed with the -OH on the surface of the three fillers, giving the nano filler low surface energy and enhancing the compatibility with ETFE resin.

[0045] In step (4), the mixing temperature is 60℃, the mixing time is 5min, and the mixing rotation speed is 300r / min.

[0046] In step (4), the ETFE film is composed of the following raw materials in parts by weight: pretreated ETFE resin 89 parts, silanized nano composite filler 5.5 parts, and tetrafluoroethylene-glycidyl methacrylate copolymer 4.5 parts.

[0047] In step (4), the temperature of the feeding section of the twin-screw extruder is 257℃, the temperature of the compression section is 273℃, the temperature of the melting section is 279℃, the reaction time is 83s, and the screw rotation speed is 190r / min.

[0048] In step (4), a vacuum devolatilization port is arranged in the twin-screw extruder, the vacuum devolatilization port is located at the end of the melting section, the vacuum degree is -0.09MPa, and the vacuum devolatilization port is used for removing residual silane oligomers.

[0049] In step (4), the longitudinal stretching multiple is 3.5 times, and the longitudinal stretching temperature is 203℃.

[0050] In step (4), the transverse stretching multiple is 3.1 times, and the transverse stretching temperature is 233℃.

[0051] In step (4), the heat setting temperature is 177℃, the heat setting time is 33s, and after natural cooling to 50℃, the ETFE film is wound to prepare the ETFE film.

[0052] In step (5), the post-treatment is that the ETFE film prepared in step (4) is kept at 137℃ for 3h, and then naturally cooled to room temperature, so as to eliminate the residual internal stress during extrusion molding, and finally clean cleaning and drying are carried out to prepare the ETFE film for semiconductor packaging, and the clean cleaning and drying include: ① soaking in ultrapure water for 14min, gentle stirring to avoid scratching the film surface, ② ultrasonic cleaning with 0.1% perfluorohexyl ethanol for 5min, ultrasonic power is 130W, which enhances the impurity stripping without damaging ETFE; ③ ultrapure water rinsing for 3 times to remove residual cleaning agent; and ④ 73℃ vacuum drying for 1h to avoid ring opening of epoxy groups caused by high temperature.

[0053] Example 2 The method for preparing the ETFE thin film for semiconductor packaging described in Example 2 consists of the following steps: (1) Preparation of tetrafluoroethylene-glycidyl methacrylate copolymer ① Deionized water, ammonium 4,8-dioxa-3H-perfluorononanoate, and potassium persulfate were added to a high-pressure reactor. After sealing the reactor, the air inside was replaced with nitrogen three times. Then, tetrafluoroethylene was introduced until the pressure inside the reactor reached 0.2 MPa. Nitrogen was replaced twice, and the pressure was purged to atmospheric pressure after each replacement. Tetrafluoroethylene was then introduced to raise the pressure inside the reactor to 2.5 MPa. Within 5 minutes, glycidyl methacrylate was forced into the high-pressure reactor with nitrogen. The temperature was raised to 55°C and the reactor was stirred. During the reaction, the pressure inside the reactor was maintained at 2.5 MPa by adding tetrafluoroethylene. When the reaction reached 3 hours, methanol polymerization inhibitor was added to the high-pressure reactor. Heating was stopped when the reaction reached 3.2 hours, and the temperature was lowered to room temperature to prepare a tetrafluoroethylene-glycidyl methacrylate copolymer emulsion. ② Add a coagulant to the tetrafluoroethylene-glycidyl methacrylate copolymer emulsion, stir to precipitate the copolymer, and then wash and dry to prepare the tetrafluoroethylene-glycidyl methacrylate copolymer. (2) Pretreatment of ETFE resin Pretreated ETFE resin was prepared by keeping ETFE resin at 150℃ in air for 2.5 hours and then cooling it naturally. (3) Silanization treatment of nanocomposite fillers ① Dissolve halloysite nanotubes, nano-lanthanum fluoride and nano-zirconium silicate in deionized water, then add ammonia to adjust the pH of the system to 9.0, and sonicate at 33℃ for 30 min; ② Add 1H,1H,2H,2H-perfluorodecyltriethoxysilane solution dropwise to the above reaction system, reflux at 81℃ for 4h, then filter, wash, dry and sieve to prepare silanized nanocomposite filler. (4) The pretreated ETFE resin, the silanized nanocomposite filler and the tetrafluoroethylene-glycidyl methacrylate copolymer are mixed evenly and then fed into a twin-screw extruder for melt blending to obtain a blend. The blend is extruded into sheets through a T-die and finally subjected to longitudinal stretching, transverse stretching and heat setting to prepare an ETFE film. (5) The ETFE film obtained in step (4) is post-processed to obtain an ETFE film for semiconductor packaging.

[0054] The mass of 4,8-dioxa-3H-perfluorononanoic acid ammonium in step (1) ① accounts for 0.4% of the mass sum of deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium, potassium persulfate, tetrafluoroethylene and glycidyl methacrylate.

[0055] The mass of potassium persulfate in step (1) ① accounts for 0.2% of the mass sum of tetrafluoroethylene and glycidyl methacrylate.

[0056] The molar ratio of the total amount of tetrafluoroethylene to glycidyl methacrylate in step (1) ① is 10:1.

[0057] The mass of deionized water in step (1) ① is 3 times the mass sum of tetrafluoroethylene and glycidyl methacrylate.

[0058] The mass of the methanol polymerization inhibitor in step (1) ① accounts for 0.17% of the mass sum of tetrafluoroethylene and glycidyl methacrylate.

[0059] The coagulant in step (1) ② is a saturated sodium chloride solution, and the volume of the coagulant added is 5% of the volume of the tetrafluoroethylene-glycidyl methacrylate copolymer emulsion.

[0060] The stirring time in step (1) ② is 19 min, the washing is deionized water washing 3 times, and the drying is vacuum drying at 55°C for 10h.

[0061] The mass ratio of halloysite nanotubes, nano lanthanum fluoride and nano zirconium silicate in step (3) ① is 2:1:2.

[0062] The mass sum of halloysite nanotubes, nano lanthanum fluoride and nano zirconium silicate in step (3) ① accounts for 2% of the mass of deionized water.

[0063] The 1H,1H,2H,2H-perfluorodecyl triethoxysilane solution in step (3) ② is prepared by uniformly mixing 1H,1H,2H,2H-perfluorodecyl triethoxysilane and anhydrous ethanol according to a volume ratio of 1:2, and the dropwise adding speed of the 1H,1H,2H,2H-perfluorodecyl triethoxysilane solution is 0.7mL / min.

[0064] The mass of 1H,1H,2H,2H-perfluorodecyl triethoxysilane added in the 1H,1H,2H,2H-perfluorodecyl triethoxysilane solution in step (3) ② accounts for 5.5% of the mass sum of halloysite nanotubes, nano lanthanum fluoride and nano zirconium silicate in step (3) ①.

[0065] The washing in step (3) ② is deionized water washing 3 times and anhydrous ethanol washing 1 time, the drying is vacuum drying at 80°C for 12h, and the sieving is sieving through a 200 mesh sieve.

[0066] In step (3), firstly, -OH is generated on the surface of LaF3 and ZrSiO4 by hydration of weak base, to provide same reaction sites for subsequent covalent grafting, then fluorosilane is condensed with -OH on the surface of the three fillers, to endow the nano-filler with low surface energy and enhance the compatibility with ETFE resin.

[0067] In step (4), the mixing temperature is 60℃, the mixing time is 5min, and the mixing rotation speed is 300r / min.

[0068] In step (4), the ETFE film is composed of the following raw materials in parts by weight: pretreated ETFE resin 88 parts, nano-composite filler 4.5 parts, and tetrafluoroethylene-glycidyl methacrylate copolymer 5.5 parts.

[0069] In step (4), the temperature of the feeding section of the twin-screw extruder is 256℃, the temperature of the compression section is 272℃, the temperature of the melting section is 278℃, the reaction time is 80s, and the screw rotation speed is 190r / min.

[0070] In step (4), a vacuum devolatilization port is arranged in the twin-screw extruder, which is located at the end of the melting section, and the vacuum degree is -0.09MPa, which is used for removing residual silane oligomers.

[0071] In step (4), the longitudinal stretching multiple is 3.0, and the longitudinal stretching temperature is 200℃.

[0072] In step (4), the transverse stretching multiple is 2.8, and the transverse stretching temperature is 230℃.

[0073] In step (4), the heat setting temperature is 175℃, the heat setting time is 30s, and the ETFE film is prepared by winding after natural cooling to 50℃.

[0074] In step (5), the post-treatment is to heat the ETFE film prepared in step (4) at 135℃ for 3h, and then naturally cool to room temperature, so as to eliminate the residual internal stress during extrusion molding, and finally clean and dry, to prepare the ETFE film for semiconductor packaging. The cleaning and drying include: ① soaking in ultrapure water for 13min, and gently stirring to avoid scratching the film surface, ② ultrasonic cleaning with 0.1% perfluorohexyl ethanol for 5min, with ultrasonic power of 130W, to enhance the impurity stripping without damaging ETFE; ③ rinsing with ultrapure water for 3 times to remove residual cleaning agent; and ④ vacuum drying at 70℃ for 1h to avoid ring-opening of epoxy groups caused by high temperature.

[0075] Example 3 The preparation method of the ETFE film for semiconductor packaging in this example 3 comprises the following steps: (1) Preparation of tetrafluoroethylene-glycidyl methacrylate copolymer ①Deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium and potassium persulfate were added into a high-pressure reactor, the high-pressure reactor was sealed, the air in the reactor was replaced with nitrogen for 3 times, then tetrafluoroethylene was introduced until the pressure in the reactor reached 0.2 MPa, the nitrogen was replaced for 2 times, and the reactor was emptied to normal pressure after each replacement, then tetrafluoroethylene was continuously introduced until the pressure in the reactor reached 2.5 MPa, glycidyl methacrylate was pressed into the high-pressure reactor with nitrogen within 5 min, the temperature was raised to 58°C for stirring reaction, and tetrafluoroethylene was supplemented during the reaction to maintain the pressure in the reactor at 2.5 MPa; when the reaction was carried out for 3 h, methanol was added into the high-pressure reactor as a polymerization inhibitor, the heating was stopped when the reaction was carried out for 3.4 h, and the temperature was lowered to room temperature, thereby obtaining a tetrafluoroethylene-glycidyl methacrylate copolymer emulsion; ②The tetrafluoroethylene-glycidyl methacrylate copolymer emulsion was added with a coagulant, and the copolymer was precipitated by stirring, then washed and dried, thereby obtaining a tetrafluoroethylene-glycidyl methacrylate copolymer; (2) Pretreatment of ETFE resin The ETFE resin was heated at 150°C in an air atmosphere for 2.5 h, and naturally cooled, thereby obtaining a pretreated ETFE resin; (3) Silanization treatment of nanocomposite filler ①The halloysite nanotube, nano lanthanum fluoride and nano zirconium silicate were dissolved in deionized water, then ammonia water was added to adjust the pH value of the system to 9.0, and the system was ultrasonically treated at 35°C for 30 min; ②The 1H,1H,2H,2H-perfluorodecyltriethoxysilane solution was added dropwise into the above reaction system, and the system was refluxed at 83°C for 4 h, then filtered, washed, dried and sieved, thereby obtaining a silanized nanocomposite filler; (4) The pretreated ETFE resin, the silanized nanocomposite filler and the tetrafluoroethylene-glycidyl methacrylate copolymer were uniformly mixed, then fed into a twin-screw extruder for melt blending, thereby obtaining a blend, the blend was extruded into a sheet through a T-shaped die, and finally longitudinally stretched, transversely stretched and heat set, thereby obtaining an ETFE film; (5) The ETFE film obtained in step (4) was post-treated, thereby obtaining an ETFE film for semiconductor packaging.

[0076] In step (1) ①, the mass of 4,8-dioxa-3H-perfluorononanoic acid ammonium accounts for 0.4% of the total mass of deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium, potassium persulfate, tetrafluoroethylene and glycidyl methacrylate.

[0077] The mass of potassium persulfate in step (1) ① accounts for 0.23% of the total mass of tetrafluoroethylene and glycidyl methacrylate.

[0078] The total amount of tetrafluoroethylene in step (1) ① accounts for 11% of the total amount of glycidyl methacrylate.

[0079] The mass of deionized water in step (1) ① accounts for 3 times of the total mass of tetrafluoroethylene and glycidyl methacrylate.

[0080] The mass of methanol polymerization inhibitor in step (1) ① accounts for 0.17% of the total mass of tetrafluoroethylene and glycidyl methacrylate.

[0081] The coagulant in step (1) ② is a saturated sodium chloride solution, and the volume of the coagulant added accounts for 5% of the volume of the tetrafluoroethylene-glycidyl methacrylate copolymer emulsion.

[0082] The stirring time in step (1) ② is 20 min, the washing is deionized water washing for 5 times, and the drying is vacuum drying at 55°C for 10 h.

[0083] The mass ratio of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate in step (3) ① is 2:1:2.

[0084] The total mass of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate in step (3) ① accounts for 3% of the mass of deionized water.

[0085] The 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane solution in step (3) ② is prepared by mixing 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane and anhydrous ethanol in a volume ratio of 1:2, and the dropwise adding speed of the 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane solution is 0.7 mL / min.

[0086] The mass of 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane added in the 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane solution in step (3) ② accounts for 5.5% of the total mass of halloysite nanotubes, nano lanthanum fluoride, and nano zirconium silicate in step (3) ①.

[0087] The washing in step (3) ② is deionized water washing for 3 times and anhydrous ethanol washing for 1 time, the drying is vacuum drying at 80°C for 12 h, and the sieving is sieving through a 200-mesh sieve.

[0088] In step (3), first, LaF3 and ZrSiO4 surfaces are made to generate -OH through hydration of a weak base, providing the same reaction site for subsequent covalent grafting, and then the surface energy of the nano filler is given through the condensation of fluorosilane with the -OH on the surface of the three fillers, enhancing the compatibility with ETFE resin.

[0089] The mixing temperature in step (4) is 60℃, the mixing time is 5 min, and the mixing speed is 300 r / min.

[0090] The ETFE film in step (4) is composed of the following raw materials in parts by weight: pretreated ETFE resin 90 parts, silanized nanocomposite filler 6.5 parts, and tetrafluoroethylene-glycidyl methacrylate copolymer 5.5 parts.

[0091] In step (4), the feeding section temperature of the twin-screw extruder is 258℃, the compression section temperature is 274℃, the melting section temperature is 280℃, the reaction time is 85 s, and the screw speed is 190 r / min.

[0092] In step (4), a vacuum devolatilization port is arranged in the twin-screw extruder, which is located at the end of the melting section, and the vacuum degree is -0.09 MPa, which is used to remove residual silane oligomers.

[0093] In step (4), the longitudinal stretching multiple is 4.0 times, and the longitudinal stretching temperature is 205℃.

[0094] In step (4), the transverse stretching multiple is 3.5 times, and the transverse stretching temperature is 235℃.

[0095] In step (4), the heat setting temperature is 180℃, the heat setting time is 35 s, and after natural cooling to 50℃, the ETFE film is wound to prepare the ETFE film.

[0096] In step (5), the post-treatment is to heat the ETFE film prepared in step (4) at 140℃ for 3 h, then naturally cool to room temperature, so as to eliminate the residual internal stress during extrusion molding, and finally clean and dry, to prepare the ETFE film for semiconductor packaging. The cleaning and drying includes: ① soaking in ultrapure water for 15 min, gentle stirring to avoid scratching the film surface, ② ultrasonic cleaning with 0.1% perfluorohexyl ethanol for 5 min, the ultrasonic power is 130 W, which enhances the impurity stripping without damaging the ETFE; ③ ultrapure water rinsing for 3 times to remove residual cleaning agent; ④ vacuum drying at 75℃ for 1 h to avoid ring-opening of the epoxy group caused by high temperature.

[0097] Comparative Example 1 The preparation method of the ETFE film for semiconductor packaging in this comparative example 1 is the same as that in example 1, the only difference is that no halloysite nanotubes are added in step (3), and the mass ratio of nanometer lanthanum fluoride to nanometer zirconium silicate in step (3) ① is 1:2.

[0098] Comparative Example 2 The preparation method of the ETFE film for semiconductor packaging according to the comparative example 2 is the same as that of the example 1, the only difference is that no nano lanthanum fluoride is added in step (3), and the mass ratio of the halloysite nanotube to the nano zirconium silicate in step (3) ① is 1:1.

[0099] Comparative example 3 The preparation method of the ETFE film for semiconductor packaging according to the comparative example 3 is the same as that of the example 1, the only difference is that no nano zirconium silicate is added in step (3), and the mass ratio of the halloysite nanotube to the nano lanthanum fluoride in step (3) ① is 2:1.

[0100] The ETFE films for semiconductor packaging prepared in the examples 1-3 and the comparative examples 1-3 are subjected to performance testing, the ETFE film prepared according to the application is cut to prepare a standard rectangular tensile sample with a size of 20 mm x 5 mm, the sample is prepared by punching to ensure that there is no visible defect. Then the sample is fixed on a clamp, and then the sample is stretched at a speed of 10 mm / min according to the ISO 527 standard, the wear resistance is detected according to the national standard GB / T 5478-2008 “Plastic Rolling Wear Test Method”, the sample is cut into a square with a side length of 100 mm, and a hole with a diameter of 6.5 mm is opened in the center, the sample is weighed before and after the test, and the precision is 1 mg, (the mass of the sample before the test-the mass of the sample after the test) / the mass of the sample before the test x 100%=wear rate (%); three samples are prepared for each sample for determination, and the test data is taken as the average value; the test results are shown in Table 1. Table 1 Performance test results of the ETFE film for semiconductor packaging

[0101] As shown in Table 1, the breaking tensile strength of the ETFE film for semiconductor packaging prepared according to the application is much greater than that of the comparative examples 1-3, and the wear rate is much smaller than that of the comparative examples 1-3. In the comparative examples 1-3, the performance of the prepared ETFE film is reduced due to the absence of any one of the halloysite nanotube, the nano lanthanum fluoride or the nano zirconium silicate in the nano composite filler.

[0102] The above is only a preferred embodiment of the application, and does not limit the application in any form. Although the application has been disclosed as above with a preferred embodiment, it is not intended to limit the application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the application, and any equivalent embodiments with equivalent changes and modifications made on the basis of the above embodiments are still within the scope of the technical solution of the application.

Claims

1. A method for preparing an ETFE film for semiconductor packaging, characterized by: consists of the following steps: (1) Preparation of tetrafluoroethylene-glycidyl methacrylate copolymer ① Deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium and potassium persulfate are added into a high-pressure reaction kettle, the high-pressure reaction kettle is sealed, the air in the kettle is replaced with nitrogen for 3 times, then tetrafluoroethylene is introduced until the pressure in the kettle is 0.2 MPa, the nitrogen is replaced for 2 times, each time after replacement, the kettle is emptied to normal pressure, then tetrafluoroethylene is continuously introduced until the pressure in the kettle is 2.5 MPa, glycidyl methacrylate is pressed into the high-pressure reaction kettle with nitrogen within 5 min, the reaction is stirred by heating to 55-58℃, and tetrafluoroethylene is supplemented during the reaction to maintain the pressure in the kettle at 2.5 MPa; when the reaction is carried out for 3 h, methanol polymerization inhibitor is added into the high-pressure reaction kettle, the heating is stopped when the reaction is carried out for 3.2-3.4 h, and the temperature is reduced to room temperature, thereby preparing a tetrafluoroethylene-glycidyl methacrylate copolymer emulsion; ② The tetrafluoroethylene-glycidyl methacrylate copolymer emulsion is added with a coagulant, the copolymer is precipitated by stirring, and the tetrafluoroethylene-glycidyl methacrylate copolymer is prepared by washing and drying; (2) Pretreatment of ETFE resin The ETFE resin is heated at 150℃ in an air atmosphere for 2.5 h, and naturally cooled, thereby preparing pretreated ETFE resin; (3) Silanization treatment of nanocomposite filler ① The halloysite nanotube, nanometer lanthanum fluoride and nanometer zirconium silicate are dissolved in deionized water, then ammonia water is added to adjust the pH value of the system to 9.0, and the system is ultrasonically treated at 33-35℃ for 30 min; ② The 1H,1H,2H,2H-perfluorodecyltriethoxysilane solution is added dropwise into the above reaction system, the reaction is carried out at 81-83℃ for 4 h, then the system is filtered, washed, dried and sieved, thereby preparing the silanized nanocomposite filler; (4) The pretreated ETFE resin, the silanized nanocomposite filler and the tetrafluoroethylene-glycidyl methacrylate copolymer are uniformly mixed, then are put into a twin-screw extruder for melt blending, thereby obtaining a blend, the blend is extruded into a sheet through a T-shaped die, and finally is longitudinally stretched, transversely stretched and heat set, thereby preparing an ETFE film; (5) The ETFE film prepared in step (4) is post-treated, thereby preparing an ETFE film for semiconductor packaging.

2. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The mass of 4,8-dioxa-3H-perfluorononanoic acid ammonium in step (1) ① accounts for 0.4% of the mass sum of deionized water, 4,8-dioxa-3H-perfluorononanoic acid ammonium, potassium persulfate, tetrafluoroethylene and glycidyl methacrylate; The mass of potassium persulfate in step (1) ① accounts for 0.2-0.23% of the mass sum of tetrafluoroethylene and glycidyl methacrylate; The total amount of tetrafluoroethylene introduced in step (1) ① is 10-11:1 in molar ratio to glycidyl methacrylate; The mass of deionized water in step (1) ① is 3 times of the mass sum of tetrafluoroethylene and glycidyl methacrylate; The mass of methanol polymerization inhibitor in step (1) ① accounts for 0.17% of the mass sum of tetrafluoroethylene and glycidyl methacrylate.

3. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The coagulating agent in step (1) ② is saturated sodium chloride solution, and the volume of the coagulating agent added is 5% of the volume of the tetrafluoroethylene-glycidyl methacrylate copolymer emulsion; The stirring time in step (1) ② is 18-20 min, the washing is washing 3-5 times with deionized water, and the drying is vacuum drying at 55℃ for 10 h.

4. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The mass ratio of halloysite nanotubes, nano lanthanum fluoride and nano zirconium silicate in step (3) ① is 2:1:2; The mass of halloysite nanotubes, nano lanthanum fluoride and nano zirconium silicate in step (3) ① accounts for 2-3% of the mass of deionized water.

5. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The 1H,1H,2H,2H-perfluorodecyl triethoxysilane solution in step (3) ② is prepared by uniformly mixing 1H,1H,2H,2H-perfluorodecyl triethoxysilane and anhydrous ethanol according to a volume ratio of 1:2, and the dropwise adding speed of the 1H,1H,2H,2H-perfluorodecyl triethoxysilane solution is 0.7 mL / min; The mass of 1H,1H,2H,2H-perfluorodecyl triethoxysilane in the 1H,1H,2H,2H-perfluorodecyl triethoxysilane solution in step (3) ② accounts for 5.5% of the mass of halloysite nanotubes, nano lanthanum fluoride and nano zirconium silicate in step (3) ①. The washing in step (3) ② is washing 3 times with deionized water and then washing 1 time with anhydrous ethanol, the drying is vacuum drying at 80℃ for 12 h, and the sieving is sieving through a 200 mesh sieve.

6. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The mixing temperature in step (4) is 60℃, the mixing time is 5 min, and the mixing rotation speed is 300 r / min; The ETFE film in step (4) is composed of the following raw materials in parts by weight: pretreated ETFE resin 88-90 parts, silanized nano composite filler 4.5-6.5 parts, tetrafluoroethylene-glycidyl methacrylate copolymer 3.5-5.5 parts.

7. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The feeding section temperature of the twin-screw extruder in step (4) is 256-258℃, the compression section temperature is 272-274℃, the melting section temperature is 278-280℃, the reaction time is 80-85 s, and the screw rotation speed is 190 r / min.

8. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The longitudinal stretching multiple in step (4) is 3.0-4.0 times, and the longitudinal stretching temperature is 200-205℃. The transverse stretching multiple in step (4) is 2.8-3.5 times, and the transverse stretching temperature is 230-235℃.

9. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The heat setting temperature in step (4) is 175-180℃, the heat setting time is 30-35 s, and after natural cooling to 50℃, the ETFE film is wound to prepare the ETFE film.

10. The method for preparing an ETFE thin film for semiconductor packaging according to claim 1, characterized in that: The post-treatment in step (5) is that the ETFE film prepared in step (4) is incubated at 135-140℃ for 3 h, then naturally cooled to room temperature, and finally cleaned, washed and dried to prepare the ETFE film for semiconductor packaging.

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