Invisible cutting light-cured adhesive tape and its application method

Abstract

This invention belongs to the field of semiconductor packaging technology, specifically relating to a photocurable tape for stealth dicing and its application method. The photocurable tape for stealth dicing of this invention introduces isocyanate methacrylate grafting to form urethane bonds, improving the heat resistance of the acrylic resin and its adhesion to silicon wafers. After crosslinking under ultraviolet light irradiation, the modulus of the adhesive layer rapidly increases, greatly reducing microcracks and corner chipping. The introduction of furan rings allows for reversible crosslinking with N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent, which decrosslinks upon heating. The surface of the anti-crack agent has a porous structure, allowing it to absorb stress through deformation buffer during thermal expansion, preventing the initiation and propagation of microcracks in the tape. The combined use of the anti-crack agent, spherical alumina, and boron nitride ensures uniform heating of the tape, significantly reducing cohesive strength and adhesion, facilitating separation from the silicon wafer, and minimizing adhesive residue, making it easy for the chip pick-up pin to peel off the tape.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor packaging technology, specifically relating to a photocurable tape for invisible cutting and its application method. Background Technology

[0002] Cutting tape is an adhesive tape applied to the back of semiconductor wafers. It typically uses polymer films such as polyolefins or polyesters as the substrate. Before UV irradiation, it exhibits high adhesion, conforming to the curved surface of the wafer and firmly securing it. After UV irradiation, it loses adhesion, allowing the wafer to detach easily. However, current cutting tapes harden after UV curing, causing a sharp increase in modulus. This leads to stress concentration during crack propagation, resulting in microcracks or chipping of the chip. Therefore, developing a photocurable tape that precisely matches the requirements of the entire stealth cutting process is crucial for improving chip yield and reliability in advanced manufacturing processes.

[0003] Chinese invention patent CN114517068B discloses an adhesive composition and a UV-cured anti-tack cutting tape. The adhesive composition comprises 100.0 parts by weight of a (meth)acrylate copolymer, 5.0 parts by weight of an aromatic polyurethane acrylate oligomer containing six vinyl groups, 0.5-5.0 parts by weight of a curing agent, and 3.0 parts by weight of a photoinitiator compounded from 1-hydroxycyclohexylphenyl ketone and 2,4,6-trimethylbenzoyl diphenylphosphine oxide. The UV-cured anti-tack layer of the UV-cured cutting tape provided by this invention is formed after curing the adhesive composition provided by this invention. However, the prior art has a technical problem: it does not further improve the composition of the UV-cured acrylic resin to enhance the tape's resistance to chip cutting damage. Summary of the Invention

[0004] The purpose of this invention is to provide a UV-curable tape for invisible cutting and its application method, which solves the technical problem in the prior art that the tape's resistance to chip cutting damage has not been improved by further modifying the composition of the UV-curable acrylic resin.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A light-curable tape for invisible cutting, comprising, from top to bottom, a release film layer, a light-curable pressure-sensitive adhesive layer, and a base film layer; The release film layer is made of polyethylene terephthalate and has a thickness of 20~25μm; The base film layer is a cross-linked polyolefin with a thickness of 50~150μm; The thickness of the photocurable pressure-sensitive adhesive layer is 20~100μm, and it is made from the following raw materials in parts by weight: 70~85 parts UV-curable acrylic resin, 1~3 parts photoinitiator, 5~20 parts thermally conductive and crack-resistant filler and 5~15 parts N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent; The photoinitiator is any one or a combination of photoinitiator 1173, photoinitiator 819 and photoinitiator TPO.

[0006] The preparation method of the UV-curable acrylic resin includes the following steps: S11. Add furfuryl alcohol and toluene to a reaction vessel and stir evenly. Add 6-chlorohexyl methacrylate and tetrabutylammonium hydroxide. React in an ice bath, wash, filter, rotary evaporate, and dry to obtain furan-modified acrylic monomer. S12. Add ethyl acetate to the reaction vessel, add acrylic acid, butyl acrylate and methacrylic acid, heat and stir, add azobisisobutyronitrile, heat and react, then add hydroxyethyl acrylate and furan-modified acrylic monomer, add azobisisobutyronitrile, heat and react to obtain acrylate copolymer. S13. Add the acrylate copolymer and isocyanate methacrylate to the reactor, add hydroquinone polymerization inhibitor and dibutyltin dilaurate, heat and react in a nitrogen atmosphere, cool to room temperature and add triethanolamine to neutralize, and obtain UV-curable acrylic resin.

[0007] The synthesis diagram of the furan-modified acrylic monomer is shown below:

[0008] The mass spectrometry analysis of the furan-modified acrylic monomer is shown below: m / z: 266.15 (100.0%), 267.16 (16.6%), 268.16 (2.1%).

[0009] Preferably, the mass ratio of furfuryl alcohol, toluene, 6-chlorohexyl methacrylate and tetrabutylammonium hydroxide catalyst in S11 is 100~120:80~100:220~260:5~8. The reaction is carried out in an ice bath for 36~48 hours, followed by washing with saturated sodium chloride aqueous solution and drying with anhydrous magnesium sulfate.

[0010] Preferably, the mass ratio of ethyl acetate, acrylic acid, butyl acrylate, methacrylic acid, hydroxyethyl acrylate, and furan-modified acrylic acid monomer in S12 is 100~150:15~18:3~5:18~22:30~35:22~28, the temperature is raised to 70~75℃ and the reaction is carried out for 1~2 hours, and the amount of azobisisobutyronitrile added for the first time is 0.3~0.5wt% of the total mass of acrylic acid, butyl acrylate, and methacrylic acid.

[0011] Preferably, the amount of azobisisobutyronitrile added in S12 is 0.1~0.3wt% of the total mass of hydroxyethyl acrylate and furan-modified acrylic monomers. After adding hydroxyethyl acrylate and furan-modified acrylic monomers, the temperature is raised to 75~80℃ and reacted for 1~2 hours.

[0012] Preferably, in S13, the mass ratio of acrylate copolymer, isocyanate methacrylate, hydroquinone polymerization inhibitor and dibutyltin dilaurate is 150~200:110~140:0.3~0.6:0.1~0.3, the reaction is carried out at 50~60℃ for 2~4 hours, and the chain is extended at 50~60℃ for 1~2 hours.

[0013] The preparation method of the thermally conductive and crack-resistant filler includes the following steps: S21. Add ethanol and deionized water to the reaction vessel, add tetraethyl orthosilicate dropwise, heat the reaction, add KH-550 dropwise, heat the reaction, filter to collect the solid, wash with deionized water, and dry to obtain seed microspheres. S22. Add seed microspheres and polyvinyl alcohol to deionized water and stir evenly to obtain an aqueous phase. Mix divinylbenzene and triethoxyvinylsilane, then add dimethyl silicone oil pore-forming agent and azobisisobutyronitrile initiator and stir to obtain an oil phase. Add the oil phase to the aqueous phase, stir homogenously, heat and react, add excess ethanol to demulsify, collect the solid, wash with deionized water, dry, and grind to obtain the crack-resistant additive. S23. A thermally conductive and crack-resistant filler is prepared by mixing crack-resistant additives, spherical alumina and boron nitride.

[0014] Preferably, the mass ratio of ethanol, deionized water, tetraethyl orthosilicate, and KH-550 in S21 is 50~60:40~50:6~12:1~3. After adding tetraethyl orthosilicate, the temperature is raised to 50~60℃ and reacted for 4~6 hours. Then, KH-550 is added dropwise, and the temperature is raised to 70~80℃ and reacted for 1~2 hours. Finally, the mixture is dried at 50~60℃, and the average particle size of the seed microspheres is 200~300 nm.

[0015] Preferably, in S22, the mass ratio of seed microspheres, polyvinyl alcohol, and deionized water is 5~10:0.5~2:100, the mass ratio of divinylbenzene, triethoxyvinylsilane, dimethyl silicone oil pore-forming agent, and azobisisobutyronitrile initiator is 50~60:10~20:25~35:1~2, the amount of oil phase added is 15~25wt% of the water phase, homogenize at 1000~2000 rpm for 3~5 min, heat to 70~80℃ for 1~2 h, and dry at 50~60℃.

[0016] Preferably, the mass ratio of the crack-resistant agent, spherical alumina, and boron nitride in S23 is 1~2:6~10:3~5, the average particle size of the spherical alumina is 5~8μm, and the average particle size of the boron nitride is 15~18μm.

[0017] A method for preparing a light-curing tape for invisible cutting includes the following steps: S1. Under light-protected conditions, UV-curable acrylic resin is dissolved in ethyl acetate and stirred evenly. Then, N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent, photoinitiator and thermally conductive and crack-resistant filler are added in sequence. After high-speed stirring and dispersion and vacuum degassing, the adhesive solution is obtained. S2. Apply the adhesive solution to the surface of the base film in the dark using a coating machine, and dry it to obtain a light-cured pressure-sensitive adhesive layer. S3. The release film is bonded to the coated light-cured pressure-sensitive adhesive layer, cured at room temperature, cut, and packaged in the dark to obtain the light-cured tape for invisible cutting.

[0018] Preferably, the amount of ethyl acetate added in S1 is 2 to 3 times the mass of the UV-curable acrylic resin, and the mixture is stirred and dispersed at a speed of 1500 to 2500 rpm for 15 to 25 minutes, and degassed at a vacuum degree of -0.1 to -0.095 MPa for 10 to 30 minutes.

[0019] Preferably, the S2 is dried at 70~110℃ for 1~2 hours.

[0020] Preferably, the S3 process involves aging at room temperature for 24-48 hours.

[0021] A method for applying a photocurable tape for invisible cutting involves peeling off a release film, attaching the adhesive layer of the photocurable tape to the polished surface of a wafer, curing it by irradiation with ultraviolet light at a wavelength of 355nm, and then heating it at 120~130℃ for 10~15 minutes after expansion to reduce viscosity. Finally, the wafer chip and the photocurable tape are peeled off using a push pin.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The invisible cutting light-curing tape of the present invention maintains stable adhesion after curing under ultraviolet light. During subsequent heat treatment, a reverse reaction occurs, partially cutting the cross-linked network, significantly reducing cohesive strength and adhesion, achieving a second performance leap, and facilitating the chip removal tape by the ejector pin.

[0023] 2. In the UV-curable acrylic resin of the present invention, acrylic acid and methacrylic acid provide a rigid structure, butyl acrylate provides initial adhesion as a flexible segment, and isocyanate methacrylate is introduced to form urethane bonds, which improves the heat resistance and adhesion of the acrylic resin to silicon wafers. After crosslinking under ultraviolet light, the modulus of the adhesive layer increases rapidly, changing from a viscous flow state to a highly elastic state. This enables the stress applied by the subsequent expansion ring to be uniformly and efficiently transferred to every modified line inside the wafer, achieving neat separation of the chip and greatly reducing the problems of microcracks and chipping. The introduction of furan rings can reversibly crosslink with N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent, and decrosslinking after heating, which reduces the adhesion, makes it easy to separate from the silicon wafer, and leaves very little adhesive residue.

[0024] 3. This invention uses tetraethyl orthosilicate to hydrolyze and condense into nano-silica, then introduces amino reaction sites through KH-550, and crosslinks with triethoxyvinylsilane and divinylbenzene. The resulting anti-crack additive, obtained by creating pores with dimethyl silicone oil, can crosslink with UV-cured acrylic resin, preventing debonding at the interface between filler and resin. The surface of the anti-crack additive has a porous structure, which allows it to absorb stress through deformation buffer during thermal expansion, preventing the initiation and propagation of microcracks in the tape. The anti-crack additive, spherical alumina, and boron nitride are used in combination to ensure uniform heating of the tape as a whole, avoiding problems such as insufficient heating in certain areas, residual adhesion, and uneven peeling difficulty. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A layered schematic diagram of the invisible cutting light-curing tape of the present invention is shown; Figure labels: 1 Release film layer, 2 Photocurable pressure-sensitive adhesive layer, 3 Base film layer. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1, see Figure 1As shown, a photocurable tape for invisible cutting in this embodiment includes, from top to bottom, a release film layer 1, a photocurable pressure-sensitive adhesive layer 2, and a base film layer 3; The release film layer is made of polyethylene terephthalate and has a thickness of 25 μm; The base film layer is a cross-linked polyolefin with a thickness of 50 μm; The thickness of the photocurable pressure-sensitive adhesive layer is 20 μm, and it is made from the following raw materials: 70 g of UV-curable acrylic resin, 1 g of photoinitiator, 5 g of thermally conductive and crack-resistant filler and 5 g of N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent. The photoinitiator is photoinitiator 1173.

[0029] The method for preparing UV-curable acrylic resin in this embodiment includes the following steps: S11. Add 100g of furfuryl alcohol and 85g of toluene to a reaction vessel and stir evenly. Add 220g of 6-chlorohexyl methacrylate and 5g of tetrabutylammonium hydroxide. React in an ice bath for 36h. Wash with saturated sodium chloride aqueous solution, filter, rotary evaporate, and dry with anhydrous magnesium sulfate to obtain furan-modified acrylic acid monomer. S12. Add 100g of ethyl acetate to a reaction vessel, add 15g of acrylic acid, 5g of butyl acrylate, and 18g of methacrylic acid, heat and stir, add 0.15g of azobisisobutyronitrile, heat to 70℃ and react for 1h, then add 35g of hydroxyethyl acrylate and 22g of furan-modified acrylic monomer, add 0.1g of azobisisobutyronitrile, heat to 75℃ and react for 1h to obtain an acrylate copolymer; S13. Add 150g of acrylate copolymer and 110g of isocyanate methacrylate to a reaction vessel, add 0.3g of hydroquinone polymerization inhibitor and 0.1g of dibutyltin dilaurate, heat to 50℃ in a nitrogen atmosphere and react for 2h. After the NCO content is determined to be less than 1% by di-n-butylamine titration, cool to room temperature and add triethanolamine to neutralize, thus obtaining UV-curable acrylic resin.

[0030] The preparation method of the thermally conductive and crack-resistant filler in this embodiment includes the following steps: S21. Add 50g of ethanol and 50g of deionized water to the reaction vessel, add 6.5g of tetraethyl orthosilicate dropwise, heat to 50℃ and react for 4h, add 1g of KH-550 dropwise, heat to 70℃ and react for 2h, filter to collect the solid, wash with deionized water, and dry at 50℃ to obtain seed microspheres with an average particle size of 210nm. S22. Add 5g of seed microspheres and 0.5g of polyvinyl alcohol to 100g of deionized water and stir evenly to obtain an aqueous phase. Mix 50g of divinylbenzene and 10g of triethoxyvinylsilane, then add 25g of dimethyl silicone oil pore-forming agent and 1g of azobisisobutyronitrile initiator and stir to obtain an oil phase. Add 15g of the oil phase to 100g of the aqueous phase and homogenize at 1000rpm for 3min. Heat to 70℃ and react for 2h. Add excess ethanol to demulsify, collect the solid, wash with deionized water, dry at 50℃, and grind to obtain the crack-resistant additive. S23. A thermally conductive and crack-resistant filler is prepared by mixing 1g of crack-resistant additive, 6g of spherical alumina with an average particle size of 5μm and 5g of boron nitride with an average particle size of 15μm.

[0031] This embodiment provides a method for preparing a light-curing tape for invisible cutting, comprising the following steps: S1. Under light-protected conditions, 70g of UV-curable acrylic resin was dissolved in 175g of ethyl acetate. After stirring evenly, N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent, photoinitiator and thermally conductive and crack-resistant filler were added in sequence. The mixture was stirred and dispersed at 1500rpm for 15min and degassed under a vacuum of -0.095MPa for 10min to obtain the adhesive solution. S2. Apply the adhesive solution to the surface of the base film using a coating machine in the dark, and dry it at 70°C for 2 hours to obtain a light-cured pressure-sensitive adhesive layer. S3. The release film is bonded to the coated light-cured pressure-sensitive adhesive layer, cured at room temperature for 24 hours, cut, and packaged in the dark to obtain the light-cured tape for invisible cutting.

[0032] This embodiment describes a method for applying a photocurable tape for invisible cutting. The release film is peeled off, the adhesive layer of the photocurable tape is adhered to the polished surface of the wafer, and cured by irradiation with ultraviolet light at a wavelength of 355nm. After expansion, the viscosity decreases when heated at 130°C for 10 minutes. The wafer chip and the photocurable tape are then peeled off using a push pin.

[0033] Example 2, see Figure 1 As shown, a photocurable tape for invisible cutting in this embodiment includes, from top to bottom, a release film layer, a photocurable pressure-sensitive adhesive layer, and a base film layer; The release film layer is made of polyethylene terephthalate and has a thickness of 25 μm; The base film layer is a cross-linked polyolefin with a thickness of 100 μm; The thickness of the photocurable pressure-sensitive adhesive layer is 50 μm, and it is made from the following raw materials: 80 g of UV-curable acrylic resin, 2 g of photoinitiator, 10 g of thermally conductive and crack-resistant filler and 10 g of N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent. The photoinitiator is photoinitiator 819.

[0034] The method for preparing UV-curable acrylic resin in this embodiment includes the following steps: S11. Add 110g of furfuryl alcohol and 100g of toluene to a reaction vessel and stir evenly. Add 240g of 6-chlorohexyl methacrylate and 6.5g of tetrabutylammonium hydroxide. React in an ice bath for 40h. Wash with saturated sodium chloride aqueous solution, filter, rotary evaporate, and dry with anhydrous magnesium sulfate to obtain furan-modified acrylic acid monomer. S12. Add 150g of ethyl acetate to a reaction vessel, add 18g of acrylic acid, 3g of butyl acrylate, and 20g of methacrylic acid, heat and stir, add 0.15g of azobisisobutyronitrile (AIBN) by mass, heat to 75℃ and react for 2h, then add 30g of hydroxyethyl acrylate and 28g of furan-modified acrylic monomer, add 0.15g of AIBN, heat to 80℃ and react for 2h to obtain an acrylate copolymer; S13. Add 180g of acrylate copolymer and 125g of isocyanate methacrylate to a reaction vessel, add 0.5g of hydroquinone polymerization inhibitor and 0.2g of dibutyltin dilaurate, heat to 60℃ in a nitrogen atmosphere and react for 4h. After the NCO content is determined to be less than 1% by di-n-butylamine titration, cool to room temperature and add triethanolamine to neutralize, thus obtaining UV-curable acrylic resin.

[0035] The preparation method of the thermally conductive and crack-resistant filler in this embodiment includes the following steps: S21. Add 60g of ethanol and 40g of deionized water to a reaction vessel, add 10g of tetraethyl orthosilicate dropwise, heat to 60℃ and react for 4h, add 2g of KH-550 dropwise, heat to 75℃ and react for 2h, filter to collect the solid, wash with deionized water, and dry at 60℃ to obtain seed microspheres with an average particle size of 300nm. S22. Add 10g of seed microspheres and 2g of polyvinyl alcohol to 100g of deionized water and stir evenly to obtain an aqueous phase. Mix 60g of divinylbenzene and 20g of triethoxyvinylsilane, then add 30g of dimethyl silicone oil pore-forming agent and 1.5g of azobisisobutyronitrile initiator and stir to obtain an oil phase. Add 20g of the oil phase to 100g of the aqueous phase and homogenize at 1500rpm for 5min. Heat to 75℃ and react for 2h. Add excess ethanol to demulsify, collect the solid, wash with deionized water, dry at 60℃, and grind to obtain the crack-resistant additive. S23. A thermally conductive and crack-resistant filler is prepared by mixing 1.5g of crack-resistant additive, 8g of spherical alumina with an average particle size of 8μm and 4.5g of boron nitride with an average particle size of 18μm.

[0036] This embodiment provides a method for preparing a light-curing tape for invisible cutting, comprising the following steps: S1. Under light-protected conditions, 80g of UV-curable acrylic resin was dissolved in 200g of ethyl acetate. After stirring evenly, N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent, photoinitiator and thermally conductive and crack-resistant filler were added in sequence. The mixture was stirred and dispersed at 2000rpm for 20min and degassed under a vacuum of -0.1MPa for 10min to obtain the adhesive solution. S2. Apply the adhesive solution to the surface of the base film using a coating machine in the dark, and dry it at 90°C for 2 hours to obtain a light-cured pressure-sensitive adhesive layer. S3. The release film is bonded to the coated light-cured pressure-sensitive adhesive layer, cured at room temperature for 36 hours, cut, and packaged in the dark to obtain the light-cured tape for invisible cutting.

[0037] This embodiment describes a method for applying a UV-curable tape for invisible cutting. The release film is peeled off, the adhesive layer of the UV-curable tape is adhered to the polished surface of the wafer, and cured by irradiation with ultraviolet light at a wavelength of 355nm. After expansion, the viscosity decreases when heated at 125°C for 10 minutes. The wafer chip and the UV-curable tape are then peeled off using a push pin.

[0038] Example 3, see Figure 1 As shown, a photocurable tape for invisible cutting in this embodiment includes, from top to bottom, a release film layer, a photocurable pressure-sensitive adhesive layer, and a base film layer; The release film layer is made of polyethylene terephthalate and has a thickness of 20 μm; The base film layer is a cross-linked polyolefin with a thickness of 150 μm; The thickness of the photocurable pressure-sensitive adhesive layer is 100 μm, and it is made from the following raw materials: 85 g of UV-curable acrylic resin, 3 g of photoinitiator, 20 g of thermally conductive and crack-resistant filler and 15 g of N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent. The photoinitiator is photoinitiator TPO.

[0039] The method for preparing UV-curable acrylic resin in this embodiment includes the following steps: S11. Add 120g of furfuryl alcohol and 100g of toluene to a reaction vessel and stir evenly. Add 260g of 6-chlorohexyl methacrylate and 7.5g of tetrabutylammonium hydroxide. React in an ice bath for 48h. Wash with saturated sodium chloride aqueous solution, filter, rotary evaporate, and dry with anhydrous magnesium sulfate to obtain furan-modified acrylic acid monomer. S12. Add 150g of ethyl acetate to a reaction vessel, then add 15g of acrylic acid, 5g of butyl acrylate, and 22g of methacrylic acid. Stir and heat. Add 0.2g of azobisisobutyronitrile. Heat to 75℃ and react for 2 hours. Then add 35g of hydroxyethyl acrylate and 28g of furan-modified acrylic acid monomer. Add 0.15g of azobisisobutyronitrile. Heat to 80℃ and react for 2 hours to obtain an acrylate copolymer. S13. Add 200g of acrylate copolymer and 140g of isocyanate methacrylate to a reaction vessel, add 0.6g of hydroquinone polymerization inhibitor and 0.3g of dibutyltin dilaurate, heat to 60℃ in a nitrogen atmosphere and react for 3h. After the NCO content is determined to be less than 1% by di-n-butylamine titration, cool to room temperature and add triethanolamine to neutralize, thus obtaining UV-curable acrylic resin.

[0040] The preparation method of the thermally conductive and crack-resistant filler in this embodiment includes the following steps: S21. Add 50g of ethanol and 50g of deionized water to the reaction vessel, add 12g of tetraethyl orthosilicate dropwise, heat to 60℃ and react for 6h, add 3g of KH-550 dropwise, heat to 80℃ and react for 2h, filter to collect the solid, wash with deionized water, and dry at 60℃ to obtain seed microspheres with an average particle size of 300nm. S22. Add 10g of seed microspheres and 1g of polyvinyl alcohol to 100g of deionized water and stir evenly to obtain an aqueous phase. Mix 50g of divinylbenzene and 20g of triethoxyvinylsilane, then add 35g of dimethyl silicone oil pore-forming agent and 2g of azobisisobutyronitrile initiator and stir to obtain an oil phase. Add 25g of the oil phase to 100g of the aqueous phase and homogenize at 2000rpm for 5min. Heat to 80℃ and react for 2h. Add excess ethanol to demulsify, collect the solid, wash with deionized water, dry at 60℃, and grind to obtain the crack-resistant additive. S23. A thermally conductive and crack-resistant filler is prepared by mixing 2g of crack-resistant additive, 10g of spherical alumina with an average particle size of 5μm and 5g of boron nitride with an average particle size of 15μm.

[0041] This embodiment provides a method for preparing a light-curing tape for invisible cutting, comprising the following steps: S1. Under light-protected conditions, 85g of UV-curable acrylic resin was dissolved in 250g of ethyl acetate. After stirring evenly, N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent, photoinitiator and thermally conductive and crack-resistant filler were added in sequence. The mixture was stirred and dispersed at 2500rpm for 25min and degassed under a vacuum of -0.095MPa for 30min to obtain the adhesive solution. S2. Apply the adhesive solution to the surface of the base film using a coating machine in the dark, and dry it at 110℃ for 2 hours to obtain a light-cured pressure-sensitive adhesive layer. S3. The release film is bonded to the coated light-cured pressure-sensitive adhesive layer, cured at room temperature for 48 hours, cut, and packaged in the dark to obtain the light-cured tape for invisible cutting.

[0042] This embodiment describes a method for applying a photocurable tape for invisible cutting. The release film is peeled off, the adhesive layer of the photocurable tape is adhered to the polished surface of the wafer, and cured by irradiation with ultraviolet light at a wavelength of 355nm. After expansion, the viscosity decreases when heated at 130°C for 15 minutes. The wafer chip and the photocurable tape are then peeled off using a push pin.

[0043] Comparative Example 1 differs from Example 1 in that the UV-curable acrylic resin is replaced with an aliphatic polyurethane acrylic resin of type 6161-100.

[0044] Comparative Example 2 differs from Example 1 in that no crack-resistant additive is added.

[0045] Comparative Example 3 differs from Example 1 in that the crack-resistant agent is replaced with silicon dioxide with an average particle size of 500 nm.

[0046] Performance testing The initial tack of the UV-cured tapes prepared in each example and comparative example was tested according to GB / T 4852-2002 "Test Method for Initial Tack of Pressure-Sensitive Adhesive Tapes (Rolling Ball Method)".

[0047] The initial peel strength and peel strength after heating and de-crosslinking of the light-cured tapes prepared in each example and comparative example were tested according to GB / T 2792-2014 "Test method for peel strength of adhesive tapes".

[0048] Pencil hardness tests were conducted according to GB / T 6739-2022 "Determination of Hardness of Paints and Varnishes by Pencil Method" to test the hardness of the UV-cured tapes prepared in each example and comparative example after UV curing.

[0049] The test results are shown in Table 1 below: Table 1 Test Results

[0050] As shown in Table 1, the initial tack of the photocurable tapes prepared in Examples 1-3 is 4-5#, the initial peel strength is 7.5-8.4 N / 25 mm, and the peel strength after heating and de-crosslinking is 0.2-0.3 N / 25 mm. This indicates that the photocurable tapes prepared in this invention have excellent initial adhesion, the viscosity decreases after heating, which helps to peel off the chip, and the hardness after curing under ultraviolet light is 4H. The toughness of the cured film layer is good, which can prevent brittle cracking during the cutting process.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0052] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A light-curing tape for invisible cutting, characterized in that, From top to bottom, it includes a release film layer, a photocurable pressure-sensitive adhesive layer, and a base film layer; The thickness of the photocurable pressure-sensitive adhesive layer is 20~100μm, and it is made from the following raw materials in parts by weight: 70~85 parts UV-curable acrylic resin, 1~3 parts photoinitiator, 5~20 parts thermally conductive and crack-resistant filler and 5~15 parts N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent.

2. The invisible cutting light-curing tape according to claim 1, characterized in that, The release film is made of polyethylene terephthalate with a thickness of 20-25 μm; the base film is made of cross-linked polyolefin with a thickness of 50-150 μm; and the photoinitiator is any one or a combination of photoinitiator 1173, photoinitiator 819, and photoinitiator TPO.

3. The invisible cutting light-curing tape according to claim 1, characterized in that, The preparation method of the UV-curable acrylic resin includes the following steps: S11. Add furfuryl alcohol and toluene to a reaction vessel and stir evenly. Add 6-chlorohexyl methacrylate and tetrabutylammonium hydroxide. React in an ice bath, wash, filter, rotary evaporate, and dry to obtain furan-modified acrylic monomer. S12. Add ethyl acetate to the reaction vessel, add acrylic acid, butyl acrylate and methacrylic acid, heat and stir, add azobisisobutyronitrile, heat and react, then add hydroxyethyl acrylate and furan-modified acrylic monomer, add azobisisobutyronitrile, heat and react to obtain acrylate copolymer. S13. Add the acrylate copolymer and isocyanate methacrylate to the reactor, add hydroquinone polymerization inhibitor and dibutyltin dilaurate, heat and react in a nitrogen atmosphere, cool to room temperature and add triethanolamine to neutralize, and obtain UV-curable acrylic resin.

4. The invisible cutting light-curing tape according to claim 3, characterized in that, The mass ratio of furfuryl alcohol, toluene, 6-chlorohexyl methacrylate and tetrabutylammonium hydroxide catalyst in S11 is 100~120:80~100:220~260:5~8. The reaction is carried out in an ice bath for 36~48 hours, followed by washing with saturated sodium chloride aqueous solution and drying with anhydrous magnesium sulfate.

5. The invisible cutting light-curing tape according to claim 3, characterized in that, In S12, the mass ratio of ethyl acetate, acrylic acid, butyl acrylate, methacrylic acid, hydroxyethyl acrylate, and furan-modified acrylic acid monomer is 100~150:15~18:3~5:18~22:30~35:22~28. The reaction is carried out at 70~75℃ for 1~2 hours. The initial addition of azobisisobutyronitrile is 0.3~0.5wt% of the total mass of acrylic acid, butyl acrylate, and methacrylic acid. The subsequent addition of azobisisobutyronitrile is based on the mass ratio of hydroxyethyl acrylate and furan-modified acrylic acid monomer. The total mass of acrylic monomers is 0.1~0.3wt%. After adding hydroxyethyl acrylate and furan-modified acrylic monomers, the temperature is raised to 75~80℃ and reacted for 1~2h. In S13, the mass ratio of acrylate copolymer, isocyanate methacrylate, hydroquinone polymerization inhibitor and dibutyltin dilaurate is 150~200:110~140:0.3~0.6:0.1~0.

3. The temperature is raised to 50~60℃ and reacted for 2~4h, followed by chain extension at 50~60℃ for 1~2h.

6. The invisible cutting light-curing tape according to claim 1, characterized in that, The preparation method of the thermally conductive and crack-resistant filler includes the following steps: S21. Add ethanol and deionized water to the reaction vessel, add tetraethyl orthosilicate dropwise, heat the reaction, add KH-550 dropwise, heat the reaction, filter to collect the solid, wash with deionized water, and dry to obtain seed microspheres. S22. Add seed microspheres and polyvinyl alcohol to deionized water and stir evenly to obtain an aqueous phase. Mix divinylbenzene and triethoxyvinylsilane, then add dimethyl silicone oil pore-forming agent and azobisisobutyronitrile initiator and stir to obtain an oil phase. Add the oil phase to the aqueous phase, stir homogenously, heat and react, add excess ethanol to demulsify, collect the solid, wash with deionized water, dry, and grind to obtain the crack-resistant additive. S23. A thermally conductive and crack-resistant filler is prepared by mixing crack-resistant additives, spherical alumina and boron nitride.

7. The invisible cutting light-curing tape according to claim 6, characterized in that, In S21, the mass ratio of ethanol, deionized water, tetraethyl orthosilicate, and KH-550 is 50-60:40-50:6-12:1-3. After adding tetraethyl orthosilicate, the temperature is raised to 50-60℃ and reacted for 4-6 hours. Then, KH-550 is added, and the temperature is raised to 70-80℃ and reacted for 1-2 hours. The mixture is then dried at 50-60℃, resulting in an average particle size of 200-300 nm for the seed microspheres. In S22, the mass ratio of seed microspheres, polyvinyl alcohol, and deionized water is 5-10:0.5-2:

100. Divinylbenzene and triethoxyvinylsilane are also present. The mass ratio of dimethyl silicone oil pore-forming agent to azobisisobutyronitrile initiator is 50-60:10-20:25-35:1-2, and the amount of oil phase added is 15-25 wt% of the water phase. Homogenize at 1000-2000 rpm for 3-5 min, heat to 70-80℃ for 1-2 h, and dry at 50-60℃. The mass ratio of crack-resistant agent, spherical alumina and boron nitride in S23 is 1-2:6-10:3-5, the average particle size of spherical alumina is 5-8 μm, and the average particle size of boron nitride is 15-18 μm.

8. A method for preparing a light-curing tape for invisible cutting, characterized in that, Includes the following steps: S1. Under light-protected conditions, UV-curable acrylic resin is dissolved in ethyl acetate and stirred evenly. Then, N,N'-(4,4'-methylenediphenyl)bismaleimide crosslinking agent, photoinitiator and thermally conductive and crack-resistant filler are added in sequence. After high-speed stirring and dispersion and vacuum degassing, the adhesive solution is obtained. S2. Apply the adhesive solution to the surface of the base film in the dark using a coating machine, and dry it to obtain a light-cured pressure-sensitive adhesive layer. S3. The release film is bonded to the coated light-cured pressure-sensitive adhesive layer, cured at room temperature, cut, and packaged in the dark to obtain the light-cured tape for invisible cutting.

9. The method for preparing a light-curing tape for invisible cutting according to claim 8, characterized in that, In step S1, the amount of ethyl acetate added is 2 to 3 times the mass of the UV-curable acrylic resin. The mixture is stirred and dispersed at a speed of 1500 to 2500 rpm for 15 to 25 minutes, and degassed under a vacuum of -0.1 to -0.095 MPa for 10 to 30 minutes. In step S2, the mixture is dried at 70 to 110°C for 1 to 2 hours. In step S3, the mixture is aged at room temperature for 24 to 48 hours.

10. The application method of a light-curing tape for invisible cutting according to any one of claims 1-7, characterized in that, The release film is peeled off, and the adhesive layer of the photocurable tape is attached to the polished surface of the wafer. It is then cured by irradiation with ultraviolet light at a wavelength of 355nm. After expansion, the viscosity decreases when heated at 120~130℃ for 10~15min. The wafer chip and the photocurable tape are then peeled off using a pin.

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