A low-transfer and low-precipitation silica gel protective film and its preparation method

Abstract

The present invention provides a low-transfer and low-precipitation silicone protective film and a preparation method thereof. The method includes the following steps: taking methyl vinyl silicone rubber with small molecules removed by high-temperature vacuum distillation, methyl hydrogen MQ resin, platinum catalyst, and solvent, adding them into a reaction kettle, heating and refluxing under stirring to obtain a prepolymer; taking the prepolymer, high-hydrogen silicone oil, adhesion promoter, platinum catalyst, and solvent, adding them into a mixing barrel, stirring and dispersing evenly to obtain an organosilicon pressure-sensitive adhesive; taking a PI substrate, performing corona treatment on it, coating the organosilicon pressure-sensitive adhesive thereon and curing it in an oven, laminating a bottom film, and aging to obtain the low-transfer and low-precipitation silicone protective film. First, by subjecting the raw materials to high-temperature vacuum to remove small molecules, the content of small molecules is reduced, and silicone oil precipitation and silicon transfer are reduced from the source; then, pre-polymerization and curing are carried out in advance, and the entire adhesive layer is integrated to reduce silicone oil precipitation and silicon transfer; finally, by adding diatomite loaded with carbon nanocrystals, the precipitation of silicon is further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone films, and particularly to a low-transfer and low-precipitation silicone protective film and a preparation method thereof. Background Art

[0002] In the field of semiconductor packaging, there is a packaging form that is particularly popular in the market, namely QFN (Quad-Flat No-leads Package) packaging. QFN packaging is widely used in a variety of electronic products due to its compact size and excellent electrical performance. During the QFN packaging process, the QFN packaging protective film plays a key role, especially in ensuring the positioning accuracy of the lead frame and the stability during the packaging process. The QFN packaging protective film is a single-sided tape made of polyimide (PI) as the base material and coated with an adhesive. Currently, most of the protective films on the market use acrylic adhesives, but acrylic is not resistant to high temperatures. After high temperatures, it is easy to leave residual glue or even powder, seriously affecting the quality of the packaged products. Silicone pressure-sensitive adhesives have good high-temperature resistance and stable adhesiveness. Generally, there will be no residual glue, which is very suitable for use in QFN packaging protective films. However, current silicone protective films also have some problems, such as serious silicon transfer and silicone oil precipitation, which affect the subsequent processes of QFN packaging.

[0003] Therefore, it is of great significance to prepare a low-transfer and low-precipitation silicone protective film for semiconductor packaging. Summary of the Invention

[0004] Technical problems to be solved: Aiming at the above technical problems, the purpose of the present invention is to provide a low-transfer and low-precipitation silicone protective film and a preparation method thereof. Firstly, through the establishment of an organosilicon system, an organosilicon pressure-sensitive adhesive is prepared by using materials such as methyl vinyl silicone rubber and methyl hydrogen MQ resin. The raw materials are subjected to high-temperature vacuum de-small molecules to reduce the content of small molecules, thereby reducing silicone oil precipitation and silicon transfer from the source. The organosilicon pressure-sensitive adhesive is pre-polymerized in advance and then cured, making the entire adhesive layer integrated, reducing silicone oil precipitation and silicon transfer. Then, by adding diatomite loaded with carbon nanocrystals, using the huge specific surface area of diatomite itself, the dispersibility and stability of the pressure-sensitive adhesive are improved, thereby reducing the precipitation of silicon. At the same time, due to the porous characteristics of diatomite, sufficient nucleation sites can be provided, which can promote the one-dimensional directional growth of polyaniline nanocrystals. After carbonization, a large amount of carbon nanofibers are loaded on the surface of diatomite, which can improve the internal structure and interfacial bonding force of the pressure-sensitive adhesive, further reducing the precipitation of silicon.

[0005] Technical solution: A low-transfer and low-precipitation silicone protective film, comprising a PI substrate, an organosilicon pressure-sensitive adhesive, and a bottom film. The organosilicon pressure-sensitive adhesive layer is located between the PI substrate and the bottom film. The organosilicon pressure-sensitive adhesive comprises the following weight components: 30-90 parts of methyl vinyl silicone rubber, 5-20 parts of methyl hydrogen MQ resin, 0.5-3 parts of high-hydrogen-content silicone oil, 1.5-5 parts of diatomite loaded with carbon nanocrystals, 0.5-2 parts of adhesion promoter, 0.5-3 parts of platinum catalyst, and 150-400 parts of solvent.

[0006] Further, the molecular weight of the methyl vinyl silicone rubber is 700,000-1,000,000, and the vinyl molar fraction is 0.1-1.0%; before use, small molecules are removed by high-temperature vacuum distillation to make the volatile content <0.1%.

[0007] Further, the M / Q value of the methyl hydrogen MQ resin is 0.7-0.9, and the active hydrogen content is 0.02-0.5%; the active hydrogen content of the high-hydrogen-content silicone oil is 1.2-1.6%.

[0008] Further, the preparation method of the diatomite loaded with carbon nanocrystals is as follows:

[0009] S1: Prepare an aniline monomer hydrochloric acid solution with a concentration of 0.1-0.2 mol / L;

[0010] S2: Take the diatomite and dry it, use it as a substrate, add the aniline monomer hydrochloric acid solution, and mix evenly;

[0011] S3: Dropwise add ammonium persulfate solution for polymerization. After the addition is completed, keep it warm at 5°C for 4 hours to grow polyaniline nanocrystals directionally;

[0012] S4: Take it out and wash it successively with water and ethanol;

[0013] S5: Place it in a vacuum dryer at 60°C;

[0014] S6: Pass nitrogen protection in a vacuum tube furnace and anneal it at 850-950°C for 2 hours to obtain the diatomite loaded with carbon nanocrystals.

[0015] Further, the particle size of the diatomite is 2-100 μm.

[0016] Further, the molar ratio of the aniline monomer to ammonium persulfate is 4:(1-3).

[0017] Further, the adhesion promoter is an organosiloxane with an epoxide group; the platinum catalyst is one of a platinum-vinylsiloxane complex catalyst, an alcohol-modified chloroplatinic acid catalyst, and a platinum-alkyne complex, and the platinum content is 2000-8000 ppm.

[0018] Further, the adhesion promoter is 3-glycidoxypropyltriethoxysilane and trimethoxy[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane.

[0019] Further, the platinum-vinylsiloxane complex catalyst is bis(1,3-divinyl-1,1,3,3-tetramethyldisiloxane)platinum; the alcohol-modified chloroplatinic acid catalyst is an ethanol-modified chloroplatinic acid catalyst; the platinum-alkynyl complex is a complex of bis(alkyne)(cyclodienyl)platinum.

[0020] Further, the solvent is one or more of toluene, xylene, ethyl acetate, butyl acetate, n-heptane, 120# solvent naphtha, and methyl ethyl ketone.

[0021] The preparation method of the above-mentioned low-transfer and low-bleed silicone protective film includes the following steps:

[0022] (1) Take methyl vinyl silicone rubber, methyl hydrogen-containing MQ resin, platinum catalyst, and solvent that have been subjected to high-temperature vacuum distillation to remove small molecules, add them to a reaction kettle, heat and reflux for 1 h under stirring to obtain a prepolymer;

[0023] (2) Take the prepolymer and add it to a mixing barrel, add the solvent, stir and disperse for 10 min, add diatomite loaded with carbon nanocrystals and high-hydrogen-content silicone oil under stirring, and continue to stir for 5 min; add the adhesion promoter under stirring and continue to stir for 5 min; add the platinum catalyst under stirring and continue to stir and disperse for 20 min until the material liquid is uniformly mixed to obtain an organosilicon pressure-sensitive adhesive;

[0024] (3) Take a PI substrate, subject it to corona treatment, coat the organosilicon pressure-sensitive adhesive on it and cure it in an oven, stack a bottom film, and age to obtain a low-transfer and low-bleed silicone protective film.

[0025] Further, the corona treatment conditions are: the power is 1.5 kW.

[0026] Further, the aging process in step (3) is: the aging temperature is 30-85 °C, and the aging time is 24-72 h.

[0027] The application of the above-mentioned low-transfer and low-bleed silicone protective film in semiconductor packaging.

[0028] Beneficial effects:

[0029] 1. Firstly, through the establishment of an organosilicon system, the present invention uses materials such as methyl vinyl silicone rubber and methyl hydrogen-containing MQ resin to prepare an organosilicon pressure-sensitive adhesive. By subjecting the raw materials to high-temperature vacuum to remove small molecules, the small molecule content is reduced, and the silicone oil bleeding and silicon transfer are reduced from the source;

[0030] 2. The silicone pressure-sensitive adhesive of the present invention is pre-polymerized in advance and then cured, and the entire adhesive layer is integrated, reducing the precipitation of silicone oil and silicon transfer.

[0031] 3. The present invention adds diatomite loaded with carbon nanocrystalline whiskers. Utilizing the huge specific surface area of diatomite itself, it improves the dispersibility and stability of the pressure-sensitive adhesive, thereby reducing the precipitation of silicon. At the same time, due to the porous characteristics of diatomite, it can provide sufficient nucleation sites, which can promote the one-dimensional directional growth of polyaniline nanocrystalline whiskers. After carbonization, a large amount of carbon nanofibers are loaded on the surface of diatomite, which can improve the internal structure and interfacial bonding force of the pressure-sensitive adhesive and further reduce the precipitation of silicon.

[0032] 4. The diatomite loaded with carbon nanocrystalline whiskers of the present invention has a three-dimensional porous structure, which can prevent its own aggregation, making it more uniformly dispersed in the pressure-sensitive adhesive. At the same time, the surface of diatomite contains a large number of different types of hydroxyl groups, which can combine well with the pressure-sensitive adhesive.

[0033] 5. After the protective film is coated in the present invention and undergoes aging, the reaction can be more complete, further reducing the precipitation of silicone oil and silicon transfer.

[0034] 6. In addition, the conventional silicone pressure-sensitive adhesive has poor thermal stability, and the diatomite loaded with carbon nanocrystalline whiskers can also improve the heat resistance of the pressure-sensitive adhesive. Detailed Embodiments

[0035] The present invention provides a low-transfer and low-precipitation silicone protective film and its preparation method. To make the purpose, technical solution and effects of the present invention clearer and more definite, the following will further elaborate on the present invention in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Example 1

[0037] The preparation method of diatomite loaded with carbon nanocrystalline whiskers is as follows:

[0038] S1: Prepare 80 mL of aniline monomer hydrochloride solution with a concentration of 0.15 mol / L.

[0039] S2: Take 5 g of diatomite with a particle size of 2 - 100 μm, dry it, and use it as a substrate. Add the aniline monomer hydrochloride solution and mix evenly. S3: Dropwise add ammonium persulfate solution for polymerization. After dropping, keep it at 5 °C for 4 h to grow polyaniline nanocrystalline whiskers directionally; the molar ratio of aniline monomer to ammonium persulfate is 2:1.

[0040] S4: Take it out and wash it successively with water and ethanol.

[0041] S5: Place it in a vacuum dryer at 60 °C.

[0042] S6: Under the protection of nitrogen in a vacuum tube furnace, anneal at 900 °C for 2 h to obtain diatomite loaded with carbon nanowhiskers.

[0043] Example 2

[0044] A preparation method of a low-transfer and low-precipitation silica gel protective film, comprising the following steps:

[0045] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules are removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them to a reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer.

[0046] (2) Take 100 parts of the prepolymer and add it to a mixing barrel. Add 150 parts of solvent and stir and disperse for 10 min. Under stirring, add 3.5 parts of diatomite loaded with carbon nanowhiskers and 1 part of high-hydrogen-content silicone oil, and continue to stir for 5 min; under stirring, add 1.2 parts of an adhesion promoter and continue to stir for 5 min; under stirring, add 1 part of platinum catalyst and continue to stir and disperse for 20 min until the liquid material is evenly mixed to obtain an organosilicon pressure-sensitive adhesive.

[0047] (3) Take a PI substrate, subject it to corona treatment with a power of 1.5 kW, coat the organosilicon pressure-sensitive adhesive on it and cure it in an oven, stack a bottom film, and cure at 85 °C for 72 h to obtain a low-transfer and low-precipitation silica gel protective film.

[0048] Among them, the methyl vinyl silicone rubber used has a molecular weight of 700,000, a vinyl molar fraction of 0.1%, and a volatile content of 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and an active hydrogen content of 0.05%; the high-hydrogen-content silicone oil has an active hydrogen content of 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0049] Example 3

[0050] A preparation method of a low-transfer and low-precipitation silica gel protective film, comprising the following steps:

[0051] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules are removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them to a reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer.

[0052] (2) Take 100 parts of the prepolymer and add it to the mixing tank. Add 150 parts of the solvent, stir and disperse for 10 min. While stirring, add 3.5 parts of diatomite loaded with carbon nanocrystalline whiskers and 1 part of high-hydrogen-content silicone oil, and continue stirring for 5 min. While stirring, add 1.2 parts of the adhesion promoter and continue stirring for 5 min. While stirring, add 1 part of the platinum catalyst and continue stirring and dispersing for 20 min until the liquid mixture is evenly mixed to obtain the silicone pressure-sensitive adhesive.

[0053] (3) Take the PI substrate, perform corona treatment with a power of 1.5 kW, coat the silicone pressure-sensitive adhesive on it and cure it in an oven, stack the bottom film, and cure at 85 °C for 72 h to obtain the low-transfer and low-precipitation silicone protective film.

[0054] Among them, the molecular weight of the used methyl vinyl silicone rubber is 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.1%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the active hydrogen content of the high-hydrogen-content silicone oil is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0055] Example 4

[0056] A preparation method of a low-transfer and low-precipitation silicone protective film includes the following steps:

[0057] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules are removed by high-temperature vacuum distillation, 20 parts of methyl hydrogen-containing MQ resin, 0.2 parts of platinum catalyst, and 70 parts of solvent and add them to the reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain the prepolymer.

[0058] (2) Take 100 parts of the prepolymer and add it to the mixing tank. Add 180 parts of the solvent, stir and disperse for 10 min. While stirring, add 3.5 parts of diatomite loaded with carbon nanocrystalline whiskers and 1 part of high-hydrogen-content silicone oil, and continue stirring for 5 min. While stirring, add 1.2 parts of the adhesion promoter and continue stirring for 5 min. While stirring, add 1 part of the platinum catalyst and continue stirring and dispersing for 20 min until the liquid mixture is evenly mixed to obtain the silicone pressure-sensitive adhesive.

[0059] (3) Take the PI substrate, perform corona treatment with a power of 1.5 kW, coat the silicone pressure-sensitive adhesive on it and cure it in an oven, stack the bottom film, and cure at 85 °C for 72 h to obtain the low-transfer and low-precipitation silicone protective film.

[0060] Among them, the molecular weight of the methyl vinyl silicone rubber used is 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; for the methyl hydrogen-containing MQ resin, M / Q = 0.75, and the active hydrogen content is 0.1%; for the high hydrogen-containing silicone oil, the active hydrogen content is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of No. 120 solvent naphtha, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0061] Example 5

[0062] A preparation method of a low-transfer and low-precipitation silica gel protective film includes the following steps:

[0063] (1) Take 60 parts of methyl vinyl silicone rubber from which small molecules have been removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, 0.2 part of platinum catalyst, and 70 parts of solvent and add them to a reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer;

[0064] (2) Take 100 parts of the prepolymer and add it to a mixing barrel. Add 150 parts of solvent, stir and disperse for 10 min. While stirring, add 3.5 parts of diatomite loaded with carbon nanocrystals and 1.5 parts of high hydrogen-containing silicone oil, and continue to stir for 5 min; while stirring, add 2 parts of adhesion promoter, and continue to stir for 5 min; while stirring, add 1 part of platinum catalyst, and continue to stir and disperse for 20 min until the liquid material is evenly mixed to obtain an organosilicon pressure-sensitive adhesive;

[0065] (3) Take a PI substrate, subject it to corona treatment with a power of 1.5 kW, coat the organosilicon pressure-sensitive adhesive on it and cure it in an oven, stack a bottom film, and cure at 85 °C for 72 h to obtain the low-transfer and low-precipitation silica gel protective film.

[0066] Among them, the molecular weight of the methyl vinyl silicone rubber used is 700,000, the vinyl molar fraction is 0.5%, and the volatile content is 0.05%; for the methyl hydrogen-containing MQ resin, M / Q = 0.7, and the active hydrogen content is 0.1%; for the high hydrogen-containing silicone oil, the active hydrogen content is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of No. 120 solvent naphtha, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0067] Example 6

[0068] A preparation method of a low-transfer and low-precipitation silica gel protective film includes the following steps:

[0069] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules have been removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them to a reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer;

[0070] (2) Take 100 parts of the prepolymer and add it to a mixing tank. Add 150 parts of solvent, stir and disperse for 10 min. Under stirring, add 2.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high-hydrogen-content silicone oil, and continue stirring for 5 min; Under stirring, add 1.2 parts of adhesion promoter and continue stirring for 5 min; Under stirring, add 1 part of platinum catalyst and continue stirring and dispersing for 20 min until the liquid material is evenly mixed to obtain an organosilicon pressure-sensitive adhesive;

[0071] (3) Take a PI substrate, subject it to corona treatment with a power of 1.5 kW, coat the organosilicon pressure-sensitive adhesive on it and cure it in an oven, stack the bottom film, and cure at 85 °C for 72 h to obtain a low-transfer and low-bleed silicone protective film.

[0072] Among them, the methyl vinyl silicone rubber used has a molecular weight of 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the methyl hydrogen MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the high-hydrogen-content silicone oil has an active hydrogen content of 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0073] Example 7

[0074] A preparation method of a low-transfer and low-bleed silicone protective film, comprising the following steps:

[0075] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules have been removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them to a reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer;

[0076] (2) Take 100 parts of the prepolymer and add it to a mixing tank. Add 150 parts of solvent, stir and disperse for 10 min. Under stirring, add 2.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high-hydrogen-content silicone oil, and continue stirring for 5 min; Under stirring, add 1.2 parts of adhesion promoter and continue stirring for 5 min; Under stirring, add 1 part of platinum catalyst and continue stirring and dispersing for 20 min until the liquid material is evenly mixed to obtain an organosilicon pressure-sensitive adhesive;

[0077] (3) Take a PI substrate, subject it to corona treatment with a power of 1.5 kW, coat it with a silicone pressure-sensitive adhesive and cure it in an oven, stack a bottom film, and cure it at 85°C for 72 h to obtain a low-transfer and low-bleed silicone protective film.

[0078] Among them, the molecular weight of the methyl vinyl silicone rubber used is 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the active hydrogen content of the high-hydrogen silicone oil is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0079] Example 8

[0080] A preparation method of a low-transfer and low-bleed silicone protective film, comprising the following steps:

[0081] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules have been removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them to a reaction kettle, heat to 150°C under stirring and reflux for 1 h to obtain a prepolymer;

[0082] (2) Take 100 parts of the prepolymer and add it to a mixing barrel, add 150 parts of solvent, stir and disperse for 10 min, add 5 parts of diatomite loaded with carbon nanocrystals and 1 part of high-hydrogen silicone oil under stirring, and continue to stir for 5 min; add 1.2 parts of adhesion promoter under stirring and continue to stir for 5 min; add 1 part of platinum catalyst under stirring and continue to stir and disperse for 20 min until the material liquid is evenly mixed to obtain a silicone pressure-sensitive adhesive;

[0083] (3) Take a PI substrate, subject it to corona treatment with a power of 1.5 kW, coat it with a silicone pressure-sensitive adhesive and cure it in an oven, stack a bottom film, and cure it at 85°C for 72 h to obtain a low-transfer and low-bleed silicone protective film.

[0084] Among them, the molecular weight of the methyl vinyl silicone rubber used is 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the active hydrogen content of the high-hydrogen silicone oil is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0085] Example 9

[0086] A preparation method of a low-transfer and low-precipitation silica gel protective film, comprising the following steps:

[0087] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules have been removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them to a reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer;

[0088] (2) Take 100 parts of the prepolymer and add it to a mixing barrel. Add 150 parts of solvent, stir and disperse for 10 min. While stirring, add 3.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high-hydrogen-content silicone oil, and continue to stir for 5 min; while stirring, add 1.2 parts of an adhesion promoter, and continue to stir for 5 min; while stirring, add 1 part of platinum catalyst, and continue to stir and disperse for 20 min until the material liquid is evenly mixed to obtain an organosilicon pressure-sensitive adhesive;

[0089] (3) Take a PI substrate, perform corona treatment with a power of 1.5 kW, coat the organosilicon pressure-sensitive adhesive on it and cure it in an oven, stack a bottom film, and cure at 70 °C for 48 h to obtain a low-transfer and low-precipitation silica gel protective film.

[0090] Among them, the methyl vinyl silicone rubber used has a molecular weight of 700,000, a vinyl molar fraction of 0.1%, and a volatile content of 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and an active hydrogen content of 0.05%; the high-hydrogen-content silicone oil has an active hydrogen content of 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0091] Comparative Example 1

[0092] The difference between this example and Example 2 is that the methyl vinyl silicone rubber was not subjected to high-temperature vacuum distillation, and pre-polymerization was not carried out during the preparation of the glue. Specifically:

[0093] A preparation method of a silica gel protective film, comprising the following steps:

[0094] (1) Take 50 parts of methyl vinyl silicone rubber that has not been subjected to high-temperature vacuum distillation to remove small molecules, 10 parts of methyl hydrogen-containing MQ resin, add them to a mixing barrel, then add 210 parts of solvent, stir and disperse for 10 min. While stirring, add 3.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high-hydrogen-content silicone oil, and continue to stir for 5 min; while stirring, add 1.2 parts of an adhesion promoter, and continue to stir for 5 min; while stirring, add 1.1 parts of platinum catalyst, and continue to stir and disperse for 20 min until the material liquid is evenly mixed to obtain an organosilicon pressure-sensitive adhesive;

[0095] (2) Take a PI substrate, perform corona treatment at a power of 1.5 kW, coat it with a silicone pressure-sensitive adhesive and cure it in an oven, stack a bottom film, and cure it at 85 °C for 72 h to obtain a silicone protective film.

[0096] Among them, the molecular weight of the used methyl vinyl silicone rubber is 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the active hydrogen content of the high hydrogen-containing silicone oil is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0097] Comparative Example 2

[0098] The difference between this example and Example 2 is that pre-polymerization was not carried out during the preparation of the glue. Specifically:

[0099] A method for preparing a silicone protective film includes the following steps:

[0100] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules have been removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, add them to a mixing barrel, add 210 parts of solvent, stir and disperse for 10 min, add 3.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high hydrogen-containing silicone oil under stirring, and continue to stir for 5 min; add 1.2 parts of adhesion promoter under stirring and continue to stir for 5 min; add 1.1 parts of platinum catalyst under stirring and continue to stir and disperse for 20 min until the liquid mixture is uniform to obtain a silicone pressure-sensitive adhesive; (2) Take a PI substrate, perform corona treatment at a power of 1.5 kW, coat it with the silicone pressure-sensitive adhesive and cure it in an oven, stack a bottom film, and cure it at 85 °C for 72 h to obtain a silicone protective film.

[0101] Among them, the molecular weight of the used methyl vinyl silicone rubber is 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the active hydrogen content of the high hydrogen-containing silicone oil is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0102] Comparative Example 3

[0103] The difference between this example and Example 2 is that the methyl vinyl silicone rubber was not subjected to high-temperature vacuum distillation. Specifically as follows:

[0104] A preparation method of a silica gel protective film, comprising the following steps:

[0105] (1) Take 50 parts of methyl vinyl silicone rubber without removing small molecules by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them into a reaction kettle. Heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer;

[0106] (2) Take 100 parts of the prepolymer and add it into a mixing barrel. Add 150 parts of solvent, stir and disperse for 10 min. Under stirring, add 3.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high hydrogen content silicone oil, and continue to stir for 5 min; Under stirring, add 1.2 parts of adhesion promoter, and continue to stir for 5 min; Under stirring, add 1 part of platinum catalyst, and continue to stir and disperse for 20 min until the liquid mixture is uniform to obtain an organosilicon pressure-sensitive adhesive;

[0107] (3) Take a PI substrate, perform corona treatment with a power of 1.5 kW, coat the organosilicon pressure-sensitive adhesive on it and cure it in an oven, stack a bottom film, and cure at 85 °C for 72 h to obtain the silica gel protective film.

[0108] Among them, the methyl vinyl silicone rubber used has a molecular weight of 700,000, a vinyl molar fraction of 0.1%, and a volatile content of 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and an active hydrogen content of 0.05%; the high hydrogen content silicone oil has an active hydrogen content of 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0109] Comparative Example 4

[0110] The difference between this example and Example 2 is that the methyl vinyl silicone rubber was not subjected to high-temperature vacuum distillation, no prepolymerization was carried out during the preparation of the glue, and the prepared protective film was not cured. Specifically:

[0111] A preparation method of a silica gel protective film, comprising the following steps:

[0112] (1) Take 50 parts of methyl vinyl silicone rubber without removing small molecules by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, add them into a mixing barrel, then add 210 parts of solvent, stir and disperse for 10 min. Under stirring, add 3.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high hydrogen content silicone oil, and continue to stir for 5 min; Under stirring, add 1.2 parts of adhesion promoter, and continue to stir for 5 min; Under stirring, add 1.1 parts of platinum catalyst, and continue to stir and disperse for 20 min until the liquid mixture is uniform to obtain an organosilicon pressure-sensitive adhesive;

[0113] (2) Take a PI substrate, perform corona treatment with a power of 1.5 kW, coat it with a silicone pressure-sensitive adhesive and cure it in an oven, then stack a bottom film without curing to obtain a silicone protective film.

[0114] Among them, the methyl vinyl silicone rubber used has a molecular weight of 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the high hydrogen-containing silicone oil has an active hydrogen content of 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0115] Comparative Example 5

[0116] The difference between this example and Example 2 is that the protective film is not cured. Specifically:

[0117] A preparation method of a silicone protective film includes the following steps:

[0118] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules have been removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen-containing MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent and add them to a reaction kettle. Heat to 150°C and reflux for 1 h under stirring to obtain a prepolymer.

[0119] (2) Take 100 parts of the prepolymer and add it to a mixing barrel. Add 150 parts of solvent, stir and disperse for 10 min. Under stirring, add 3.5 parts of diatomite loaded with carbon nanocrystals and 1 part of high hydrogen-containing silicone oil, and continue to stir for 5 min; under stirring, add 1.2 parts of adhesion promoter and continue to stir for 5 min; under stirring, add 1 part of platinum catalyst and continue to stir and disperse for 20 min until the liquid mixture is evenly mixed to obtain a silicone pressure-sensitive adhesive.

[0120] (3) Take a PI substrate, perform corona treatment with a power of 1.5 kW, coat it with a silicone pressure-sensitive adhesive and cure it in an oven, then stack a bottom film without curing to obtain a silicone protective film.

[0121] Among them, the methyl vinyl silicone rubber used has a molecular weight of 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the methyl hydrogen-containing MQ resin has M / Q = 0.7 and the active hydrogen content is 0.05%; the high hydrogen-containing silicone oil has an active hydrogen content of 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst with a platinum content of 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2.

[0122] Comparative Example 6

[0123] The difference between this embodiment and Embodiment 2 is that diatomite loaded with carbon nanocrystals is not added. Specifically:

[0124] A preparation method of a low-transfer and low-precipitation silica gel protective film includes the following steps:

[0125] (1) Take 50 parts of methyl vinyl silicone rubber from which small molecules are removed by high-temperature vacuum distillation, 10 parts of methyl hydrogen MQ resin, 0.1 part of platinum catalyst, and 60 parts of solvent, add them to a reaction kettle, heat to 150 °C under stirring and reflux for 1 h to obtain a prepolymer;

[0126] (2) Take 100 parts of the prepolymer and add it to a mixing barrel, add 150 parts of solvent, stir and disperse for 10 min, add 1 part of high-hydrogen-content silicone oil under stirring, and continue to stir for 5 min; add 1.2 parts of adhesion promoter under stirring, and continue to stir for 5 min; add 1 part of platinum catalyst under stirring, and continue to stir and disperse for 20 min until the material liquid is evenly mixed to obtain an organosilicon pressure-sensitive adhesive;

[0127] (3) Take a PI substrate, perform corona treatment with a power of 1.5 kW, coat the organosilicon pressure-sensitive adhesive on it and cure it in an oven, stack a bottom film, and cure at 85 °C for 72 h to obtain a low-transfer and low-precipitation silica gel protective film.

[0128] Among them, the molecular weight of the methyl vinyl silicone rubber used is 700,000, the vinyl molar fraction is 0.1%, and the volatile content is 0.05%; the M / Q of the methyl hydrogen MQ resin is 0.7, and the active hydrogen content is 0.05%; the active hydrogen content of the high-hydrogen-content silicone oil is 1.6%; the adhesion promoter is 3-glycidoxypropyltriethoxysilane; the platinum catalyst is a platinum-vinylsiloxane complex catalyst, and the platinum content is 5000 ppm; the solvent is a mixture of 120# solvent oil, ethyl acetate, and methyl ethyl ketone with a volume ratio of 1:1:2. Take the protective films obtained in each example and comparative example, remove the bottom film to obtain specimens, and detect and record the detection results of the silicon transfer rate and silicon precipitation respectively.

[0129] Among them: 1. The silicon transfer test method is: stick the protective film on a clean test steel plate, put it into an oven at 70 °C for 20 h, cool for 2 h, remove the protective film, directly stick a NITTO 31B tape, let it stand for 20 min, and test the peel strength with a tensile machine to obtain the peel strength F1. The blank value is to stick the NITTO 31B tape on a clean test steel plate, let it stand for 20 min, and test the peel strength with a tensile machine to obtain the peel strength F2.

[0130] Transfer rate = (1 - F1 / F2) * 100%

[0131] 2.2. The silicon precipitation test method is as follows: Take a circular copper foil with a diameter of 2 cm to test the dry silicon amount data on the surface of the copper foil, and obtain the dry silicon amount F3; Cut the protective film into a circular shape with a diameter of 2 cm and stick it to the surface of the copper foil, then put it into an oven at 200 °C and bake for 6 hours. After cooling, remove the protective film and test the dry silicon amount on the surface of the copper foil to obtain the dry silicon amount F4.

[0132] Silicon precipitation = (F4 - F3) * 100%

[0133] Table 1

[0134]

[0135]

[0136] As can be seen from Table 1, for the protective film obtained in the embodiments of the present invention, the silicon transfer is very small, less than 5.5%, and the silicon precipitation is less than 1.0%, which is not obvious, achieving low transfer and low precipitation.

Claims

1. A low transfer and low precipitation silicone protective film, comprising a PI substrate, an organic silicone pressure-sensitive adhesive and a base film, wherein the organic silicone pressure-sensitive adhesive layer is located between the PI substrate and the base film, and is characterized in that: The organic silicon pressure-sensitive adhesive comprises the following components by weight: 30-90 parts of methyl vinyl silicone rubber, 5-20 parts of methyl hydrogenated MQ resin, 0.5-3 parts of high hydrogenated silicone oil, 1.5-5 parts of diatomaceous earth loaded with carbon nano whiskers, 0.5-2 parts of adhesion promoter, 0.5-3 parts of platinum catalyst, and 150-400 parts of solvent; The M / Q value of the methyl hydrogen-containing MQ resin is 0.7 to 0.9, and the active hydrogen content is 0.02 to 0.5%; the active hydrogen content of the high hydrogen-containing silicone oil is 1.2 to 1.6%; The preparation method of the diatomaceous earth loaded with carbon nano whiskers is as follows: S1: preparing a hydrochloric acid solution of aniline monomer with a concentration of 0.1-0.2 mol / L; S2: Take diatomaceous earth and dry it, use it as a base, add aniline monomer hydrochloric acid solution, and mix well; S3: adding ammonium persulfate solution for polymerization, and keeping the temperature at 5°C for 4 hours after the addition is completed, so as to orient the growth of polyaniline nanowhiskers; S4: Take out and wash with water and ethanol in sequence; S5: vacuum drying at 60°C; S6: Annealing at 850-950° C. for 2 h in a vacuum tube furnace with nitrogen protection to obtain diatomaceous earth loaded with carbon nanowhiskers.

2. The low transfer and low precipitation silica gel protective film according to claim 1, characterized in that: The molecular weight of the methyl vinyl silicone rubber is 700,000 to 1,000,000, and the vinyl mole fraction is 0.1 to 1.0%. Before use, the small molecules are removed by high-temperature vacuum distillation to make the volatile content less than 0.1%.

3. The low transfer and low precipitation silica gel protective film according to claim 1, characterized in that: The molar ratio of the aniline monomer to ammonium persulfate is 4:(1-3).

4. The low transfer and low precipitation silica gel protective film according to claim 1, characterized in that: The adhesion promoter is an organic siloxane with epoxide; the platinum catalyst is one of a platinum-vinylsiloxane complex catalyst, an alcohol-modified chloroplatinic acid catalyst and a platinum acetylene complex, wherein the platinum content is 2000-8000ppm.

5. The low transfer and low precipitation silica gel protective film according to claim 1, characterized in that: The solvent is one or more of toluene, xylene, ethyl acetate, butyl acetate, n-heptane, 120# solvent oil, and butanone.

6. A method for preparing a low transfer and low precipitation silica gel protective film according to any one of claims 1 to 5, comprising the following steps: (1) Add methyl vinyl silicone rubber, methyl hydrogenated MQ resin, platinum catalyst and solvent to a reaction kettle, and heat under reflux for 1 hour under stirring to obtain a prepolymer; (2) Add the prepolymer to a mixing barrel, add the solvent, stir and disperse for 10 minutes, add the diatomaceous earth loaded with carbon nano whiskers and high hydrogen silicone oil under stirring, and continue stirring for 5 minutes; add the adhesion promoter under stirring, and continue stirring for 5 minutes; add the platinum catalyst under stirring, and continue stirring and dispersing for 20 minutes until the material liquid is evenly mixed to obtain a silicone pressure-sensitive adhesive; (3) Take the PI substrate, treat it with corona, coat it with a silicone pressure-sensitive adhesive and cure it in an oven, stack the base film, and ripen it to obtain a low transfer and low precipitation silicone protective film.

7. The method for preparing a low transfer and low precipitation silica gel protective film according to claim 6, characterized in that: The aging process in step (3) is as follows: aging temperature 30-85° C., aging time 24-72 h.

8. Use of the low transfer and low precipitation silica gel protective film according to any one of claims 1 to 5 in semiconductor packaging.

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