Preparation method of adhesive tape for semiconductor wafer processing

Abstract

The invention relates to the technical field of adhesive tapes, and particularly discloses a preparation method of an adhesive tape for semiconductor wafer processing. The viscosity-reducing adhesive tape for semiconductor processing is prepared by selecting an acrylate prepolymer as a base adhesive, selecting a multifunctional acrylate monomer as a modified monomer and adding branched chain type vinyl silicone oil and thermal expansion microspheres. Under the synergistic effect of the branched chain type vinyl silicone oil, the modified monomer and the thermal expansion microspheres, the adhesive tape disclosed by the invention can relatively thoroughly realize viscosity reduction after being subjected to UV irradiation and baking, residual adhesive is not easy to leave after the adhesive tape is torn off, and the negative influence on the wafer quality is not easy to cause.

Description

Technical Field

[0001] The present application relates to the technical field of adhesive tapes, and more specifically, to a method for preparing an adhesive tape for semiconductor wafer processing. Background Art

[0002] In the semiconductor industry, wafer processing technology includes a series of fine processing methods, such as wafer thinning, wafer cutting, etc. In the process that includes these processing methods, in order to prevent the wafer from cracking, surface defects, debris and other defects, the wafer usually needs to be fixed. The common method of fixing the wafer is to use tape for application, which not only requires the tape to provide sufficient adhesion during the entire processing process, but also requires that no residual adhesive should be left after the tape is torn off to ensure the purity of the wafer. However, traditional tapes often find it difficult to take into account both aspects of performance. Usually, while having high adhesion, they also have the disadvantage of being difficult to tear off completely. If an easy-to-tear tape is used, it is often difficult to fully fix the wafer. Therefore, it is necessary to develop a new type of tape suitable for this occasion.

[0003] UV adhesive tape is a new type of tape product developed to solve the above problems. This tape uses acrylate copolymer as the base glue, and also contains photoinitiator and multifunctional monomer. It is no different from ordinary tape when fixing wafers. After UV light, the photoinitiator can make the multifunctional monomer form an interpenetrating network structure between the acrylate copolymer. The formation of the interpenetrating network structure shrinks the volume of the glue, thereby achieving the effect of reducing the bonding force, which helps to reduce the residual glue left after the tape is torn off.

[0004] Regarding the above-mentioned related technologies, the inventors believe that the actual viscosity-reducing effect of the UV de-viscosity tape in the related technologies is still relatively limited, and a certain amount of residual adhesive will still be left during the wafer processing process, which is likely to have a negative impact on the wafer quality. Summary of the invention

[0005] The actual viscosity reduction effect of UV adhesive tape in the related art is still relatively limited, and a certain amount of residual adhesive will still be left during the wafer processing, which is likely to have a negative impact on the wafer quality. In order to improve this defect, the present application provides a method for preparing an adhesive tape for semiconductor wafer processing.

[0006] The present application provides a method for preparing an adhesive tape for semiconductor wafer processing, which adopts the following technical solution: A method for preparing an adhesive tape for semiconductor wafer processing, the method comprising the following steps: (1) Mix an acrylate prepolymer with a modified monomer, a branched vinyl silicone oil, a photoinitiator, a curing agent, and thermally expandable microspheres, and stir evenly to obtain an acrylate glue; in this step, the acrylate prepolymer is dispersed in an anhydrous ethyl acetate solvent, the dosage of the thermally expandable microspheres is 30-40% of the weight of the acrylate prepolymer, the dosage of the branched vinyl silicone oil is 0.8-1.4% of the total weight of the acrylate prepolymer, the acrylate prepolymer is copolymerized from acrylic monomers, and the modified monomer includes a polyfunctional acrylate monomer; (2) Coat the acrylate glue on the surface of a PET base film to form an adhesive layer, then dry the acrylate glue, and then cover a PET release film on the surface of the adhesive layer, and continue to dry and cure to obtain a tape for semiconductor wafer processing.

[0007] By adopting the above technical solution, the present application selects an acrylate prepolymer as the base glue, selects a polyfunctional acrylate monomer as the modified monomer, and adds a branched vinyl silicone oil and thermally expandable microspheres to prepare a (tack-reducing) tape for semiconductor processing. Before the tack-reducing tape peeling treatment, the tape of the present application needs to be heated and baked while being irradiated with UV. Under the action of UV irradiation, the branched vinyl silicone oil can cooperate with the acrylate prepolymer and the polyfunctional acrylate monomer to form an interpenetrating network structure. The addition of the branched vinyl silicone oil can make the interpenetrating network structure more fully interpenetrate in the base glue, so it can promote the shrinkage of the adhesive layer and is beneficial to the complete peeling of the adhesive layer. The surface energy of the polysiloxane side chain of the branched vinyl silicone oil is relatively low and it is easy to migrate to the surface of the adhesive layer. The polysiloxane side chain migrated to the surface can weaken the adhesion between the adhesive layer and the wafer, and can cooperate with the shrinkage of the adhesive layer, which is beneficial to the complete peeling of the adhesive layer. Baking and heating can promote the migration of the polysiloxane side chain and can also make the thermally expandable microspheres expand. The expansion of the thermally expandable microspheres will cause local protrusions on the surface of the adhesive layer, and these local protrusions cooperate with the polysiloxane side chain, increasing the difficulty of wetting the base glue and the wafer surface. Under the synergistic action of the branched vinyl silicone oil, the modified monomer, and the thermally expandable microspheres, the tape of the present application can achieve a relatively complete tack-reducing effect after UV irradiation and baking, and it is not easy to leave residual glue after tearing off the tape and is not easy to have a negative impact on the quality of the wafer.

[0008] Preferably, the thermally expandable microspheres are prepared according to the following method: (1) Mix acrylonitrile, methyl methacrylate, methyl acrylate, an initiator, a crosslinking agent, and n-hexane to obtain an oil phase for standby; prepare an aqueous dispersion of sodium hydroxide particles, and then add sodium chloride, sodium nitrite, and SDS to the aqueous dispersion of sodium hydroxide particles to obtain an aqueous phase for standby; (2) Add the oil phase to the water phase, stir and emulsify to obtain a suspension, heat the suspension under nitrogen protection, cool down and release pressure after the reaction, add hydrochloric acid for acidification, and then filter and dry to obtain thermally expandable microspheres.

[0009] By adopting the above technical solution, in this application, the oil phase containing the monomer and the foaming agent n-hexane and the water phase containing magnesium hydroxide particles are respectively prepared first, and then the water phase and the oil phase are used together to prepare thermally expandable microspheres with magnesium hydroxide particles as the core, a polymer as the shell, and n-hexane in the shell. When heated, n-hexane vaporizes and pushes the shell of the thermally expandable microspheres to expand, increasing the overall volume of the thermally expandable microspheres and achieving the thermal expansion effect.

[0010] Preferably, the modified monomer further includes unsaturated fatty acids.

[0011] By adopting the above technical solution, the molecules of unsaturated fatty acids have carbon-carbon double bonds and carboxyl groups. The carbon-carbon double bonds can participate in the formation of the interpenetrating network structure under the action of a photoinitiator, and the carboxyl groups can form hydrogen bonds with components such as acrylate prepolymers and polyfunctional acrylate monomers. Hydrogen bonds can play a tackifying role at room temperature, and after the viscosity reduction treatment, since unsaturated fatty acids participate in the formation of the interpenetrating network structure, the hydrogen bonds are weakened to a certain extent. Therefore, it can not only improve the peel strength of the tape before UV irradiation but also is not likely to affect the peel strength of the tape after UV irradiation.

[0012] Preferably, the molecules of the unsaturated fatty acids contain 3-5 carbon-carbon double bonds.

[0013] By adopting the above technical solution, this application optimizes the number of carbon-carbon double bonds in the molecules of unsaturated fatty acids, which helps to improve the crosslinking effect between unsaturated fatty acids and polyfunctional acrylate monomers, can promote the shrinkage of the adhesive layer during UV irradiation, and improves the UV viscosity reduction performance of the tape.

[0014] Preferably, the unsaturated fatty acid is selected from linolenic acid, arachidonic acid, or eicosapentaenoic acid.

[0015] By adopting the above technical solution, this application optimizes the type of unsaturated fatty acids, which helps to improve the UV viscosity reduction performance of the tape.

[0016] Preferably, the acrylic monomers include acrylic acid, methyl methacrylate, isooctyl acrylate, and glycidyl methacrylate.

[0017] By adopting the above technical solution, the present application selects acrylic acid and methyl methacrylate as hard monomers, isooctyl acrylate as a soft monomer, and glycidyl methacrylate as a functional monomer. At the same time, acrylic acid is also used as a functional monomer in combination with glycidyl methacrylate, which helps to improve the peel strength of the tape before receiving UV irradiation.

[0018] Preferably, the acrylic monomer further includes 2-hydroxyethyl acrylate.

[0019] By adopting the above technical solution, the present application further preferably selects 2-hydroxyethyl acrylate as a new functional monomer. The structural unit introduced by 2-hydroxyethyl acrylate has a hydroxyl group, which is easy to form hydrogen bonds with components such as polyfunctional acrylate monomers, so it can improve the peel strength of the tape before receiving UV irradiation and is not likely to affect the peel strength of the tape after receiving UV irradiation.

[0020] Preferably, the modified monomer further includes isocyanatoethyl methacrylate.

[0021] By adopting the above technical solution, isocyanatoethyl methacrylate can react with the hydroxyl group introduced by 2-hydroxyethyl acrylate, thereby increasing the content of carbon-carbon double bonds in the acrylate prepolymer, which helps to improve the cross-linking effect of the acrylate prepolymer and components such as polyfunctional acrylate monomers and branched vinyl silicone oil, and can promote the shrinkage of the adhesive layer under UV irradiation conditions, which helps to improve the anti-tack performance of the tape.

[0022] Preferably, the polyfunctional acrylate monomer is selected as dipentaerythritol hexaacrylate, and the dosage of dipentaerythritol hexaacrylate is 5-10% of the total weight of the acrylate prepolymer.

[0023] By adopting the above technical solution, the present application preferably selects the dosage of the polyfunctional acrylate monomer, which helps to improve the anti-tack performance of the tape.

[0024] Preferably, in the step (1), the modified nanotubes are also mixed with the acrylate prepolymer, and the modified nanotubes are prepared according to the following method: (1) Mix vinyl silane coupling agent, ethanol and water to obtain a silane modification solution for standby; (2) Add halloysite nanotubes to the silane modification solution, after heating reaction, carry out centrifugal separation, and dry the collected precipitate to obtain modified nanotubes.

[0025] By adopting the above technical solution, the present application modifies halloysite nanotubes with vinyl silane coupling agent to obtain modified nanotubes with vinyl groups on the surface. The modified nanotubes can participate in the formation of an interpenetrating network structure, which helps to improve the anti-tack performance of the tape.

[0026] In summary, the present application has the following beneficial effects: 1. In the present application, an acrylate prepolymer is selected as the base glue, a polyfunctional acrylate monomer is selected as the modifying monomer, and branched vinyl silicone oil and thermally expandable microspheres are added to prepare a (tack reduction) tape for semiconductor processing. Under the synergistic action of the branched vinyl silicone oil, the modifying monomer, and the thermally expandable microspheres, the tape of the present application can achieve tack reduction more thoroughly after UV irradiation and baking, and it is not easy to leave residual glue after the tape is torn off, and it is not easy to have a negative impact on the quality of the wafer.

[0027] 2. In the present application, unsaturated fatty acid is preferably used as the modifying monomer. The carboxyl group of the unsaturated fatty acid can form hydrogen bonds with components such as acrylate prepolymer and polyfunctional acrylate monomer. The hydrogen bonds can play a tackifying role at room temperature, and can dissociate during high-temperature baking. Therefore, it can improve the peel strength of the tape before receiving UV irradiation and is not easy to affect the peel strength of the tape after receiving UV irradiation.

[0028] 3. The present application optimizes the number of carbon-carbon double bonds in the unsaturated fatty acid molecule, which helps to improve the crosslinking effect between the unsaturated fatty acid and the polyfunctional acrylate monomer, can promote the shrinkage of the adhesive layer during UV irradiation, and improves the UV tack reduction performance of the tape. Specific Embodiments

[0029] The present application will be further described in detail below with reference to examples, preparation examples, and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0030] Preparation Example of Thermally Expandable Microspheres The following takes Preparation Example 1 as an example for illustration.

[0031] Preparation Example 1 In this preparation example, azodiisovaleronitrile is selected as the initiator, and aliphatic polyurethane acrylate crosslinking agent CN9010 is selected as the crosslinking agent.

[0032] In this preparation example, the thermally expandable microspheres are prepared according to the following method: (1) Acrylonitrile, methyl methacrylate, methyl acrylate, initiator, crosslinking agent, and n-hexane are mixed in a weight ratio of 60:20:20:2.5:0.5:30 to obtain an oil phase for standby; sodium hydroxide solution is added to magnesium chloride solution to obtain a magnesium hydroxide aqueous dispersion with a magnesium hydroxide mass fraction of 2.5 wt%, and then the magnesium hydroxide aqueous dispersion, sodium chloride, sodium nitrite, and SDS are mixed in a ratio of 100:5:0.005:0.005 to obtain an aqueous phase for standby; (2)The oil phase was added to the water phase at a weight ratio of 1:4, and the mixture was stirred and emulsified at a rate of 8000 rpm for 2 min to obtain a suspension. The suspension was heated in a water bath under a nitrogen protection of 2.0 MPa, maintained at a temperature of 65 °C, and stirred at a rate of 200 rpm for 24 h. After the reaction was completed, the temperature was lowered and the pressure was released, and hydrochloric acid was added for acidification to adjust the pH to 2. Then, filtration and drying were carried out to obtain thermally expandable microspheres with a mesh size of 150.

[0033] Preparation Example of Modified Nanotubes Taking Preparation Example 2 as an example, it is described as follows.

[0034] Preparation Example 2 In this preparation example, the modified nanotubes were prepared according to the following method:

[0035] (1)Vinyltriethoxysilane, ethanol, and water were mixed at a weight ratio of 8:90:10 to obtain a silane modification solution for standby. (2)Halloysite nanotubes were added to the silane modification solution at a solid-liquid ratio of 1:50, heated and reacted at 80 °C for 5 h, followed by centrifugal separation. The collected precipitate was dried to obtain modified nanotubes.

[0036] Examples Examples 1 - 5 Taking Example 1 as an example, it is described as follows.

[0037] Example 1 In this example, the acrylate prepolymer was prepared according to the following method: (1)Acrylic acid, isooctyl acrylate, glycidyl methacrylate, and methyl methacrylate were mixed at a weight ratio of 8:65:16:10 to obtain a mixed monomer. Then, the mixed monomer was mixed with ethyl acetate at a weight ratio of 4:6 to obtain a monomer dispersion. One-third of the monomer dispersion was used as the bottom material in the kettle, heated to 55 °C under nitrogen protection, and then continuously stirred at a rate of 100 r / min. (2)The remaining monomer dispersion, an initiator AVBN with a weight of 1% of the total monomer weight, and a chain transfer agent NDM with a weight of 0.5% of the total monomer weight were added to the reaction kettle over a period of 2 h. Then, the temperature was raised to 65 °C, and the reaction was continued at a constant temperature for 5 h, followed by cooling and discharging to obtain the acrylate prepolymer.

[0038] In this embodiment, the thermally expandable microspheres were prepared according to the method of Preparation Example 1, and the amount of the thermally expandable microspheres was 30% of the weight of the acrylate prepolymer (abbreviated as the microsphere ratio in Table 1); the vinyl content of the branched vinyl silicone oil was 1.5 wt%, and the amount of the branched vinyl silicone oil was 0.8% of the total weight of the acrylate prepolymer (abbreviated as the silicone oil ratio in Table 1); the modified monomer was a polyfunctional acrylate monomer, specifically dipentaerythritol hexaacrylate was selected, and the amount of dipentaerythritol hexaacrylate was 2.5% of the total weight of the acrylate prepolymer. The photoinitiator TPO was selected, and the amount of the photoinitiator was 2% of the total weight of the acrylate prepolymer. The curing agent was an aromatic isocyanate curing agent (L75), and the amount was 1% of the total weight of the acrylate prepolymer.

[0039] This embodiment provides a method for preparing a tape for semiconductor wafer processing, including the following steps: (1) Mix the acrylate prepolymer with the modified monomer, branched vinyl silicone oil, photoinitiator, curing agent, and thermally expandable microspheres, and stir evenly to obtain an acrylate glue; (2) Coat the acrylate glue on the surface of a 50-μm-thick PET substrate film to form an adhesive layer, then dry the acrylate glue at 120°C for 3 h, control the dry adhesive thickness to be 100 μm, and then cover a PET release film on the surface of the adhesive layer, and dry and cure at 60°C for 48 h to obtain a tape for semiconductor wafer processing.

[0040] As shown in Table 1, the main differences between Examples 1-5 lie in the different microsphere ratios and silicone oil ratios.

[0041] Table 1 Microsphere ratio and silicone oil ratio Sample Example 1 Example 2 Example 3 Example 4 Example 5 Proportion of microspheres / % 30 32 35 38 40 Proportion of silicone oil / % 0.8 0.9 1.1 1.2 1.4 Example 6

[0042] The difference between this embodiment and Example 5 is that the modified monomer further includes unsaturated fatty acid, the amount of the unsaturated fatty acid is 1.5% of the total weight of the acrylate prepolymer, and oleic acid is selected as the unsaturated fatty acid.

[0043] Example 7 The difference between this embodiment and Example 6 is that linolenic acid is selected as the unsaturated fatty acid.

[0044] Example 8 The difference between this embodiment and Example 7 is that arachidonic acid is selected as the unsaturated fatty acid.

[0045] Example 9 The difference between this embodiment and Example 8 is that eicosapentaenoic acid is selected as the unsaturated fatty acid.

[0046] Example 10 The difference between this example and Example 8 is that the acrylic monomers used to synthesize the acrylate prepolymer further include 2-hydroxyethyl acrylate, and the molar ratio of 2-hydroxyethyl acrylate to acrylic acid is 1:8.

[0047] Example 11 The difference between this example and Example 10 is that the modified monomer further includes isocyanatoethyl methacrylate, and the dosage of isocyanatoethyl methacrylate is 1% of the total weight of the acrylate prepolymer.

[0048] Examples 11 - 15 As shown in Table 2, the difference between Examples 11 - 15 is that the percentage of dipentaerythritol hexaacrylate in the total weight of the acrylate prepolymer (abbreviated as DPHA ratio) is different.

[0049] Table 2 DPHA ratio Sample Proportion of DPHA / % Example 11 2.5 Example 12 5 Example 13 7 Example 14 9 Example 15 10 Example 16

[0050] The difference between this example and Example 15 is that in step (1) of preparing the tape for semiconductor wafer processing, the modified nanotubes are also mixed with the acrylate prepolymer. The modified nanotubes are prepared according to the method of Preparation Example 2, and the dosage of the modified nanotubes is 0.8% of the total weight of the acrylate prepolymer.

[0051] Comparative example Comparative Example 1 The difference between this comparative example and Example 1 is that the components of the acrylate adhesive do not include thermally expandable microspheres and branched vinyl silicone oil.

[0052] Comparative Example 2 The difference between this comparative example and Example 1 is that the components of the acrylate adhesive do not include thermally expandable microspheres.

[0053] Comparative Example 3 The difference between this comparative example and Example 1 is that the components of the acrylate adhesive do not include branched vinyl silicone oil.

[0054] Performance detection test method I. Peel strength Referring to "GB / T 3280 - 1992", the 180° peel strength is measured on a universal testing machine. During the test, a 25 - mm - wide tape is bonded to the wafer, and after 20 min, a peel test is carried out at a peel rate of 300 mm / min to measure the peel strength before viscosity reduction. Based on the peel strength before viscosity reduction of Comparative Example 1, calculate the ratio between the peel strength before viscosity reduction measured for each example and comparative example and the peel strength before viscosity reduction of Comparative Example 1, which is the relative initial strength. The results are shown in Table 3.

[0055] II. Tack Reduction Performance Attach the tape to the surface of the wafer in the same manner as in the peel strength test, then irradiate it with ultraviolet light using a mercury lamp at an energy density of 200 ± 10 mJ / cm2, and then heat it at 145 °C for 3 min. After waiting for cooling, test the 180° peel strength, which is recorded as the peel strength after tack reduction. Based on the peel strength after tack reduction of Comparative Example 1, calculate the ratio between the peel strength after tack reduction measured in each example and comparative example and the peel strength after tack reduction of Comparative Example 1, which is the relative tack reduction strength. The results are shown in Table 3.

[0056] Table 3 Test Results Sample Relative initial strength / % Relative viscosity reduction strength / % Sample Relative initial strength / % Relative viscosity reduction strength / % Example 1 102.6 81.9 Example 11 111.8 72.6 Example 2 102.1 80.6 Example 12 111.9 72.1 Example 3 102.3 79.4 Example 13 111.8 71.4 Example 4 102.2 78.1 Example 14 111.9 70.8 Example 5 102.5 77.3 Example 15 112.0 70.2 Example 6 107.8 76.5 Example 16 Example 7 108.1 75.4 Comparative Example 1 100.0 100.0 Example 8 108.0 74.8 Comparative Example 2 100.9 94.6 Example 9 108.2 74.1 Comparative Example 3 101.7 91.5 Example 10 111.5 74.4 / / / Combining Examples 1-5 and Comparative Examples 1-3 and referring to Table 3, it can be seen that the relative initial strength measured in Examples 1-5 is close to that in Comparative Examples 1-3, while the relative tack reduction strength is significantly lower than that in Comparative Example 1. This shows that under the synergistic effect of branched vinyl silicone oil, modified monomer, and expandable microspheres, the tape of the present application can achieve a relatively thorough tack reduction effect after UV irradiation and baking, and it is not easy to leave residual glue after tearing off the tape, and it is not easy to have a negative impact on the quality of the wafer. When at least one of expandable microspheres and branched vinyl silicone oil is missing, it is difficult to fully exert the above synergistic effect, so the tack reduction effect of the tape is poor.

[0057] Combining Example 5 and Examples 6-9 and referring to Table 3, it can be seen that the relative initial strength measured in Examples 6-9 is higher than that in Example 5 because the carboxyl group of unsaturated fatty acid can form hydrogen bonds with components such as acrylate prepolymer and polyfunctional acrylate monomer, and the hydrogen bonds can play a tackifying role at room temperature. The relative tack reduction strength measured in Examples 6-9 is lower than that in Example 5 because after the tack reduction treatment, unsaturated fatty acid participates in the formation of the interpenetrating network structure, which weakens the hydrogen bonds to a certain extent, so it does not have a significant impact on the peel strength of the tape after UV irradiation. When the molecule of unsaturated fatty acid contains 3-5 carbon-carbon double bonds, it helps to improve the crosslinking effect between unsaturated fatty acid and polyfunctional acrylate monomer, and can fully promote the shrinkage of the adhesive layer during UV irradiation, further improving the UV tack reduction performance of the tape.

[0058] Combining Example 9 and Example 10 and referring to Table 3, it can be seen that the relative initial strength measured in Example 10 is higher than that in Example 9 because the structural unit introduced by 2-hydroxyethyl acrylate has a hydroxyl group and is easy to form hydrogen bonds with components such as polyfunctional acrylate monomer, so it can improve the peel strength of the tape before UV irradiation. At the same time, under the synergistic effect of factors such as the interpenetrating network structure and expandable microspheres, the addition of 2-hydroxyethyl acrylate does not cause a significant increase in the relative tack reduction strength.

[0059] Combined with Example 10 and Example 11 and in conjunction with Table 3, it can be seen that the relative tack reduction strength measured in Example 11 is lower than that in Example 10. This is because isocyanatoethyl methacrylate can react with the hydroxyl groups introduced by 2-hydroxyethyl acrylate, thereby increasing the content of carbon-carbon double bonds in the acrylate prepolymer, which helps to improve the crosslinking effect of the acrylate prepolymer with components such as multifunctional acrylate monomers and branched vinyl silicone oil, and can promote the shrinkage of the adhesive layer under UV irradiation conditions, contributing to the improvement of the tack reduction performance of the tape.

[0060] Combined with Examples 11 - 15 and in conjunction with Table 3, it can be seen that when the dosage of dipentaerythritol hexaacrylate is 5 - 10% of the total weight of the acrylate prepolymer, it helps to improve the tack reduction performance of the tape.

[0061] Combined with Example 15 and Example 16 and in conjunction with Table 3, it can be seen that the relative tack reduction strength measured in Example 16 is lower than that in Example 15. This is because the modified nanotubes can participate in the formation of the interpenetrating network structure through the vinyl groups on the surface, enabling the interpenetrating network structure and the thermally expandable microspheres to play a more effective synergistic role, thus contributing to the improvement of the tack reduction performance of the tape.

[0062] The above embodiments are merely explanations of the present application and not limitations thereof. Those skilled in the art can make modifications to the embodiments of the present application without creative contributions according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing an adhesive tape for semiconductor wafer processing, characterized in that: The method comprises the following steps: (1) mixing an acrylate prepolymer with a modified monomer, a branched vinyl silicone oil, a photoinitiator, a curing agent and heat-expandable microspheres, and stirring them uniformly to obtain an acrylate glue; in this step, the acrylate prepolymer is dispersed in an anhydrous ethyl acetate solvent, the amount of the heat-expandable microspheres is 30-40% by weight of the acrylate prepolymer, the amount of the branched vinyl silicone oil is 0.8-1.4% by weight of the total acrylate prepolymer, the acrylate prepolymer is copolymerized by acrylic acid monomers, and the modified monomers include multifunctional acrylate monomers; (2) Applying acrylate glue to the surface of the PET substrate film to form a glue layer, then drying the acrylate glue, and then covering the surface of the glue layer with a layer of PET release film, and further drying and ripening to obtain an adhesive tape for semiconductor wafer processing.

2. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 1, characterized in that: The heat-expandable microspheres are prepared as follows: (1) acrylonitrile, methyl methacrylate, methyl acrylate, an initiator, a crosslinking agent, and n-hexane are mixed to obtain an oil phase, which is set aside; a sodium hydroxide particle aqueous dispersion is prepared, and then sodium chloride, sodium nitrite, and SDS are added to the sodium hydroxide particle aqueous dispersion to obtain a water phase, which is set aside; (2) The oil phase is added to the water phase, and a suspension is obtained after stirring and emulsification. The suspension is heated under nitrogen protection. After the reaction is completed, the temperature is reduced and the pressure is released. Hydrochloric acid is added for acidification, and then the suspension is filtered and dried to obtain heat-expandable microspheres.

3. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 2, characterized in that: The modifying monomer also includes unsaturated fatty acids.

4. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 3, characterized in that: The unsaturated fatty acid molecules contain 3-5 carbon-carbon double bonds.

5. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 4, characterized in that: The unsaturated fatty acid is selected from linolenic acid, arachidonic acid, or eicosapentaenoic acid.

6. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 1, characterized in that: The acrylic monomers include acrylic acid, methyl methacrylate, isooctyl acrylate and glycidyl methacrylate.

7. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 6, characterized in that: The acrylic monomer further includes 2-hydroxyethyl acrylate.

8. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 7, characterized in that: The modified monomer also includes isocyanoethyl methacrylate.

9. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 1, characterized in that: The multifunctional acrylate monomer is dipentaerythritol hexaacrylate, and the amount of the dipentaerythritol hexaacrylate is 5-10% of the total weight of the acrylate prepolymer.

10. The method for preparing an adhesive tape for semiconductor wafer processing according to claim 9, wherein in step (1), the modified nanotubes are further mixed with an acrylate prepolymer, and the modified nanotubes are prepared according to the following method: (1) Mixing a vinyl silane coupling agent, ethanol and water to obtain a silane modified liquid for later use; (2) Adding halloysite nanotubes to the silane modified solution, heating the solution and then centrifuging the solution, and drying the collected precipitate to obtain the modified nanotubes.