UV viscosity-reducing adhesive, preparation method and viscosity-reducing film for wafer cutting

Abstract

The invention discloses a UV viscosity-reducing adhesive, a preparation method and a viscosity-reducing film for wafer cutting. The UV viscosity-reducing glue comprises acrylate resin, epoxy resin, a photosensitive composition, an antistatic agent, a curing agent, a photoinitiator and a solvent, the photosensitive composition comprises a photosensitive monomer and an organic silicon modified photosensitive prepolymer, and the proportion of the organic silicon modified photosensitive prepolymer is 20 to 50 weight percent; the raw materials of the organic silicon modified photosensitive prepolymer comprise an acrylate monomer and hydrogen-containing siloxane, the acrylate monomer and the hydrogen-containing siloxane are subjected to hydrosilylation in the presence of a platinum catalyst, and the molar ratio of alkenyl in the acrylate monomer to hydrogen in the hydrogen-containing siloxane is 1: (0.4-0.6); the functionality of the acrylate monomer is not less than 2. On the premise of maintaining good peeling strength before UV of the viscosity-reducing adhesive, the peeling strength after UV of the viscosity-reducing adhesive is reduced, and the problem that the yield of wafers is reduced due to the fact that the peeling strength of the current viscosity-reducing adhesive is high after UV irradiation is solved.

Description

Technical Field

[0001] The present application relates to the field of UV anti-viscosity adhesives, and in particular to a UV anti-viscosity adhesive, a preparation method, and an anti-viscosity film for wafer cutting. Background Art

[0002] In semiconductor manufacturing and back-end packaging processes, a protective film with special adhesive properties needs to be attached to the back of the wafer before dicing. The core function of this protective film is to firmly adhere to and fix the die during intense mechanical processing such as cutting and grinding, effectively suppressing "chip flying" or displacement caused by vibration or stress impact, ensuring the physical integrity and position accuracy of the die, and thus guaranteeing the reliability of subsequent pick-up and packaging processes. To achieve this critical function, the protective film must provide extremely high initial peel strength during processing (usually up to 500-2500gf / 25mm or even higher) to ensure excellent shear resistance and adhesion between the wafer and film interface.

[0003] Ultraviolet light-curing viscosity-reducing adhesive (UV viscosity-reducing adhesive) is the core material layer that achieves this function. Its mechanism of action relies on the unique design of the photochemical response: under normal conditions without ultraviolet (UV) radiation, the polymer network in the adhesive layer (usually based on acrylate polymers) maintains a moderate cross-linking density and contains mobile active monomers or oligomers, giving the material high viscoelasticity and strong wettability and interfacial adhesion to the surface of the adherend (such as silicon wafers, glass, ceramics or various substrates). When the processing is completed and the protective film needs to be removed, the photoinitiator in the adhesive layer is rapidly decomposed by UV radiation of a specific wavelength and energy to produce active free radicals or cations, triggering a rapid and deep cross-linking reaction of the pre-set polymerizable double bonds (acrylate groups) in the system. This light-curing process causes significant changes in the polymer network structure: on the one hand, the density of covalent bonds between molecular chains increases dramatically, limiting the mobility of molecular segments, significantly increasing the material modulus (rigidity), and essentially losing surface tack. On the other hand, the adhesive layer shrinks in volume, significantly reducing its actual contact area with the adherend surface (usually required to be less than 10gf / 25mm), and greatly weakening physical adsorption effects such as van der Waals forces. Ideally, after UV irradiation, the adhesive layer's peel strength should rapidly and significantly decrease to an extremely low level, allowing for a nearly frictionless, clean, and easy peel of the die or workpiece.

[0004] However, existing UV-treated films, particularly those based on widely used PVC (polyvinyl chloride) or PO (polyolefin) substrates, suffer from insufficient peel strength reduction after UV irradiation. Some products exhibit elevated peel forces (significantly exceeding 10gf / 25mm) even after UV treatment. This results in excessive mechanical force being applied during die removal, which can easily lead to micro-cracking or even chipping of ultra-thin or brittle dies, resulting in yield loss. Summary of the Invention

[0005] In order to solve the problem that the current UV de-viscosity adhesive has a high peel strength after UV irradiation, which easily causes a loss in product yield, the present application provides a UV de-viscosity adhesive, a preparation method and a de-viscosity film for wafer cutting, which reduces the peel strength after UV irradiation without ensuring the good peel strength of the de-viscosity adhesive before UV irradiation.

[0006] In a first aspect, the present application provides a UV viscosity-reducing adhesive comprising the following raw materials in parts by weight:

[0007] 20-40 parts of acrylate resin, 5-10 parts of epoxy resin, 20-35 parts of photosensitive composition, 0.5-2 parts of antistatic agent, 0.5-1 part of curing agent, 0.5-1.5 parts of photoinitiator, and 15-25 parts of solvent; the photosensitive composition comprises a photosensitive monomer and an organosilicon-modified photosensitive prepolymer, wherein the organosilicon-modified photosensitive prepolymer accounts for 20-50 wt%;

[0008] The raw materials of the organosilicon-modified photosensitive prepolymer include acrylate monomers and hydrogen-containing siloxanes, which are subjected to hydrosilylation under a platinum catalyst, and the molar ratio of the alkenyl group in the acrylate monomer to the hydrogen group in the hydrogen-containing siloxane is 1:(0.4-0.6); the functionality of the acrylate monomer is not less than 2.

[0009] In any of the above technical solutions, the acrylate monomer is any one or more of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipropylene glycol ester, and ethoxylated pentaerythritol tetraacrylate.

[0010] In any of the above technical solutions, the hydrogen-containing siloxane is selected from any one or more of trimethoxysilane, triethoxysilane, methyldimethoxysilane and ethyldimethoxysilane.

[0011] This application constructs a glue layer system with high cohesive strength and strong interfacial adhesion before UV irradiation through the synergistic effect of acrylate resin and epoxy resin. Acrylate resin provides a toughness basis for resistance to cutting stress, while the rigid skeleton of epoxy resin and the cross-linking reaction with curing agent further enhance the high-temperature adhesion of the glue layer, ensuring that the initial peel strength is stable within a safe range. The photosensitive composition serves as a functional carrier for UV response, which introduces a silicone-modified photosensitive prepolymer. Before UV irradiation, the siloxane group in the prepolymer can be hydrolyzed to form silanol (Si-OH), forming hydrogen bonds or condensation reactions with the silanol (Si-OH) on the surface of the wafer, significantly compensating for the loss of interfacial adhesion due to the low surface energy of silicone, and avoiding the problem of decreased initial adhesion caused by traditional silicone modification. After UV irradiation, the photoinitiator triggers the rapid cross-linking and curing of the residual double bonds in the prepolymer to form an organosilicon phase (a polymerization product of the organosilicon-modified photosensitive prepolymer), which undergoes microphase separation from the acrylate / epoxy resin matrix, forming a continuous low-surface-energy organosilicon weak boundary layer at the interface, which sharply weakens physical adsorption effects such as van der Waals forces, and reduces the peel strength to an ideal level of ≤10gf / 25mm.

[0012] The above-mentioned prepolymer is synthesized through the hydrosilylation reaction of an acrylate monomer and a hydrogenated siloxane. It is important to note that an acrylate monomer with a functionality of ≥2 means it contains at least two alkenyl functional groups. The molar ratio of alkenyl groups to Si-H bonds in the reaction system should be strictly controlled to 1:(0.4-0.6) to ensure a balance between the product's photoreactivity and its ability to inhibit peel strength.

[0013] In any of the above technical solutions, the raw materials of the organosilicon-modified photosensitive prepolymer include polyisocyanate, the polyisocyanate and the reaction product of hydrosilylation are subjected to addition polymerization, and the molar ratio of the hydroxyl group in the acrylate monomer to the isocyanate group in the polyisocyanate is 1:(0.5-0.6).

[0014] The present application has no particular limitation on the polyisocyanate, which may be selected from any one or more of aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates.

[0015] In any of the above technical solutions, the polyisocyanate is preferably an aliphatic polyisocyanate, which helps to improve the flexibility of the viscosity-reducing film.

[0016] Exemplarily, the aliphatic polyisocyanate is hexamethylene diisocyanate (HDI).

[0017] In the synthesis of silicone-modified photosensitive prepolymers, polyisocyanates (such as HDI) are further introduced to react with the hydroxyl groups of the hydrosilylation intermediate (the aforementioned acrylate monomer is required to have a hydroxyl group) to form a prepolymer with a moderately cross-linked network structure. On the one hand, the cross-linked network of the prepolymer can physically bind small molecules such as photosensitive monomers and antistatic agents in the adhesive layer, reducing the risk of their migration to the interface during storage or high-temperature environments, ensuring the long-term maintenance of the uniformity and high peel strength of the pre-UV adhesive layer, and avoiding the problems of post-UV peel strength rebound (re-adhesion) and adhesive film residue during peeling. On the other hand, the prepolymer increases the cohesive density of the post-UV adhesive layer, intensifies curing shrinkage, further weakens the contact area between the adhesive layer and the wafer, and cooperates with the weak boundary layer of silicone to achieve ultra-low peel force.

[0018] It is worth noting that the low surface energy of the silicone segment in the prepolymer promotes the inhibition of the migration of small molecular components.

[0019] In any of the above technical solutions, the photosensitive monomer is selected from a monofunctional monomer, a difunctional monomer and a multifunctional monomer in a mass ratio of 3-5:1-3:1-2.

[0020] Monofunctional monomers provide molecular chain flexibility and fluidity, improving the wettability of the adhesive layer to the wafer surface and enhancing initial adhesion before UV treatment. Difunctional monomers balance reactivity and crosslinking density to avoid excessive shrinkage that leads to interfacial stress concentration. Multifunctional monomers act as crosslinking nodes to ensure the rapid formation of a high-density network after UV treatment, and their limited usage reduces the risk of brittleness. The three work together to ensure a high curing rate while avoiding adhesive layer embrittlement caused by excessive multifunctional monomers, reducing the edge collapse rate and achieving a steady decrease in peel strength after UV treatment.

[0021] In any of the above technical solutions, the monofunctional monomer is a photosensitive acrylate monomer containing one alkenyl group, preferably any one or more of hydroxyethyl methacrylate, ethoxyethyl acrylate, ethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, butyl acrylate, methyl methacrylate, acrylic acid, and diisooctyl maleate.

[0022] In any of the above technical solutions, the bifunctional monomer is a photosensitive acrylate monomer containing two alkenyl groups, preferably any one or more of tripropylene glycol diacrylate, dipropylene glycol diacrylate, hexylene glycol diacrylate, neopentyl glycol diacrylate, diethylene glycol divinyl ether, and ethoxylated bisphenol A epoxy acrylate.

[0023] In any of the above technical solutions, the multifunctional monomer is a photosensitive acrylate monomer containing at least 3 alkenyl groups, preferably any one or more of methyl propane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylol propane triacrylate, pentaerythritol tetraacrylate, ditrimethylol propane tetraacrylate, and dipentaerythritol penta / hexaacrylate.

[0024] Typically, but not limiting, the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, novolac epoxy resin, and phenol novolac epoxy resin.

[0025] The present application has no particular limitation on the epoxy equivalent of the epoxy resin, but it is preferably 100 to 500 g / eg.

[0026] In any of the above technical solutions, the weight average molecular weight of the acrylic resin is 400,000 to 1,000,000.

[0027] In any of the above technical solutions, the antistatic agent is selected from any one or more of polythiophene derivatives, polyaniline derivatives, ethoxylated aliphatic alkylamines, graphene and its derivatives, carbon black, and lithium sulfonate salts.

[0028] In any of the above technical solutions, the curing agent is an amine curing agent and / or an acid anhydride curing agent.

[0029] Exemplarily, the amine curing agent is selected from any one or more of polyethylene polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, ethylenediamine, and hexamethylenediamine.

[0030] Exemplarily, the anhydride curing agent is selected from any one or more of phthalic anhydride, maleic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, and pyromellitic dianhydride.

[0031] The photoinitiator of the present application can be a photoinitiator commonly used by those skilled in the art, including but not limited to any one or more of benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, 1-hydroxycyclohexylbenzophenone (184), 2-hydroxy-methylphenylpropane, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (907), 2.4.6-(trimethylbenzoyl)-diphenylphosphine oxide (TPO), alkane-1-one (1173), and DR-575.

[0032] The solvent of the present application can be a commonly used solvent well known to those skilled in the art, including but not limited to any one or more of ethanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, acetone, butanone, cyclohexanone, methyl isobutyl ketone, propylene glycol methyl ether, dipropylene glycol methyl ether, toluene, and xylene.

[0033] In the second aspect, the present application provides a method for preparing a UV viscosity-reducing adhesive. According to any of the UV viscosity-reducing adhesive ratios, an acrylate resin, an epoxy resin, a photosensitive composition, an antistatic agent and a solvent are mixed to obtain a mixture; a photoinitiator is added to the mixture in the dark and mixed, and finally a curing agent is added and stirred evenly to obtain the mixture.

[0034] In a second aspect, the present application provides a de-viscosity film for wafer dicing, comprising a substrate, any one of the aforementioned UV de-viscosity adhesives, and a release film stacked in sequence.

[0035] The present application has no special restrictions on the substrate, and materials familiar to those skilled in the art can be selected, including but not limited to polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, polyurethane, polyethylene terephthalate and other polyesters, polyimide, polyetheretherketone, polyvinyl chloride, and polyvinylidene chloride.

[0036] The present application has no special restrictions on the release film, and materials familiar to those skilled in the art can be selected, including but not limited to films made of the following materials: polyethylene, polypropylene, polybutadiene, polymethylpentene, polyethylene terephthalate, polyethylene naphthalate, polysiloxane, polysuccinate terephthalate, (methylene) acrylate copolymer, polystyrene, polycarbonate, cellulose acetate, cellulose triacetate, polyimide, and polytetrafluoroethylene.

[0037] In summary, this application has the following beneficial effects:

[0038] The UV viscosity-reducing adhesive of the present application achieves a reliable initial peeling force greater than ≥1500gf / 25mm through the synergy of the acrylate / epoxy resin matrix and the silicone-modified photosensitive prepolymer, relying on the hydrolysis adhesion of the siloxane group and the high strength of the resin before UV irradiation, and effectively prevents flying crystals during cutting. After UV irradiation, light triggers the cross-linking of double bonds and the separation of silicone phases in the prepolymer to form a weak interface layer, which stably reduces the peeling force to ≤10gf / 25mm and avoids hidden cracks in the grains. The cross-linked prepolymer structure with the introduction of polyisocyanate inhibits the migration of small molecules, ensures long-term storage stability, and ultimately obtains a wafer cutting viscosity-reducing film with high process adaptability and low peeling residue. DETAILED DESCRIPTION

[0039] Preparation Example

[0040] Preparation Example 1

[0041] The organosilicon-modified photosensitive prepolymer is prepared by the following method:

[0042] Step 1: Under nitrogen protection, add 10 mol of pentaerythritol triacrylate, 2000 g of toluene, and 30.5 g of a polymerization inhibitor (hydroquinone) to a reactor, heat to 80°C, and stir to dissolve to obtain a reaction solution. Mix 15 mol of trimethoxysilane and 35 mg of a platinum catalyst (Karstedt catalyst solution) and stir to obtain a mixed solution. Add the mixed solution dropwise to the reaction solution (complete the addition within 1 hour), and maintain the reaction temperature at 80°C for 4 hours. After the reaction is completed, remove unreacted silane and toluene by vacuum distillation at 80°C / -0.095 MPa to obtain an intermediate.

[0043] Step 2: Cool the intermediate obtained above to 60°C, add 5.5 mol of hexamethylene diisocyanate dropwise (complete within 1 hour), and then add 2.3 g of dibutyltin dilaurate. Raise the temperature to 80°C and react for 3 hours. After the reaction is complete, cool to 40°C, add 300 g of acetone to dilute, and filter to remove gel particles to obtain a silicone-modified photosensitive prepolymer.

[0044] Preparation Example 2

[0045] The organosilicon-modified photosensitive prepolymer is prepared by the following method:

[0046] Step 1: Under nitrogen protection, add 10 mol of dipentaerythritol pentaacrylate, 3500 g of ethyl acetate, and 33.6 g of a polymerization inhibitor (hydroquinone) to a reactor, heat to 75°C, and stir to dissolve to obtain a reaction solution. Mix 20 mol of methyldimethoxysilane and 30 mg of a platinum catalyst (Karstedt catalyst solution) and stir to obtain a mixed solution. Add the mixed solution dropwise to the reaction solution (complete the addition within 1 hour) and maintain the reaction temperature at 80°C for 4 hours. After the reaction is completed, remove unreacted silane and ethyl acetate by vacuum distillation at 75°C / -0.09 MPa to obtain an intermediate.

[0047] Step 2: Cool the intermediate obtained above to 60°C, add 5.0 mol of hexamethylene diisocyanate dropwise (complete within 1 hour), and then add 2.0 g of dibutyltin dilaurate. Raise the temperature to 75°C and react for 2.5 hours. After the reaction is complete, cool to 40°C, add 300 g of acetone to dilute, and filter to remove gel particles to obtain a silicone-modified photosensitive prepolymer.

[0048] Preparation Example 3

[0049] The organosilicon-modified photosensitive prepolymer is prepared by the following method:

[0050] Step 1: Under nitrogen protection, 10 mol of dipropylene glycol ester, 2500 g of propylene glycol methyl ether, and 30.0 g of polymerization inhibitor (hydroquinone) were added to a reactor, heated to 85 ° C and stirred to dissolve to obtain a reaction solution. 11.6 mol of triethoxysilane and 30 mg of platinum catalyst (Karstedt catalyst solution) were mixed and stirred to obtain a mixed solution, which was added dropwise to the reaction solution (dripped within 1 hour) and maintained at 85 ° C for 5 hours. After the reaction was completed, unreacted silane and propylene glycol methyl ether were removed by reduced pressure distillation at 85 ° C / -0.01 MPa to obtain an intermediate.

[0051] Step 2: Cool the intermediate obtained above to 60°C, add 5.8 mol of hexamethylene diisocyanate dropwise (complete within 1 hour), and then add 4.6 g of dibutyltin dilaurate. Raise the temperature to 85°C and react for 3.5 hours. After the reaction is complete, cool to 40°C, add 300 g of acetone to dilute, and filter to remove gel particles to obtain a silicone-modified photosensitive prepolymer.

[0052] Preparation Example 4

[0053] The difference between the organosilicon-modified photosensitive prepolymer and Preparation Example 1 is that the amount of hexamethylene diisocyanate added in step 2 is 4.5 mol.

[0054] Preparation Example 5

[0055] The difference between the organosilicon-modified photosensitive prepolymer and Preparation Example 1 is that the amount of hexamethylene diisocyanate added in step 2 is 6.5 mol.

[0056] Preparation Example 6

[0057] The organosilicon-modified photosensitive prepolymer is prepared by the following method:

[0058] Under nitrogen, add 10 mol of pentaerythritol triacrylate, 2000 g of toluene, and 18.5 g of a polymerization inhibitor (hydroquinone) to a reactor, heat to 80°C, and stir to dissolve to obtain a reaction solution. 5 mol of trimethoxysilane and 25 mg of a platinum catalyst (Karstedt catalyst solution) are mixed and stirred to obtain a mixed solution. This mixed solution is added dropwise to the reaction solution (complete addition within 1 hour), and the reaction temperature is maintained at 80°C for 4 hours. After the reaction is complete, remove unreacted silane and toluene by vacuum distillation at 80°C / -0.095 MPa to obtain the product.

[0059] Preparation Example 7

[0060] The difference between the organosilicon-modified photosensitive prepolymer and Preparation Example 1 is that the amount of trimethoxysilane added in step 1 is 9 mol (the molar ratio of alkenyl groups to hydrogen groups is 1:0.3).

[0061] Preparation Example 8

[0062] The difference between the organosilicon-modified photosensitive prepolymer and Preparation Example 1 is that the amount of trimethoxysilane added in step 1 is 21 mol (the molar ratio of alkenyl groups to hydrogen groups is 1:0.7).

[0063] Preparation Example 9

[0064] The modified photosensitive prepolymer is prepared by the following method:

[0065] Add 10 mol of pentaerythritol triacrylate to a reaction kettle, add 3.5 mol of hexamethylene diisocyanate dropwise (complete within 1 hour), and then add 1.9 g of dibutyltin dilaurate. Heat to 80°C and react for 3 hours. After the reaction is complete, cool to 40°C, dilute with 200 g of acetone, and filter to remove gel particles to obtain a modified photosensitive prepolymer.

[0066] Example

[0067] Example 1, a wafer dicing adhesive reduction film, is prepared according to the following steps:

[0068] Raw material selection: 330g acrylate resin, brand BASF S790, Mw = 750,000; 52g of epoxy resin, brand Nan Ya NPEL-128, epoxy equivalent 184-194g / eq; 290g of photosensitive composition, comprising 90g of the organosilicon-modified photosensitive prepolymer of Preparation Example 1, 100g of butyl acrylate, 50g of 1,6-hexanediol diacrylate, and 50g of pentaerythritol triacrylate; antistatic agent ( PAG.CDV polyaniline derivative) 15g; curing agent (Huntsman D-230 polyetheramine) 8g; photoinitiator (IGM TPO+184, mass ratio 1:1) 12g; solvent (ethyl acetate:propylene glycol methyl ether = 3:1) 220g.

[0069] Acrylate resin, epoxy resin, photosensitive composition, antistatic agent and 80wt% solvent are added to a reactor and stirred for 1.5h; in the dark, photoinitiator and 10wt% solvent are mixed evenly and added to the reactor, mixed and stirred for 30min; finally, curing agent and remaining solvent are mixed and added to the stirring kettle, mixed and stirred for 30min to prepare UV viscosity-reducing adhesive.

[0070] Use a coating machine to apply UV adhesive to a 50µm thick PO substrate. After coating, place the substrate in a 90°C oven for 2 minutes. After drying, the film thickness is approximately 20±2µm. A PET light release film is attached to the dried UV adhesive and cured at 60°C for 48 hours to obtain a film suitable for wafer dicing.

[0071] Example 2, a wafer dicing adhesive reduction film, is prepared according to the following steps:

[0072] Raw material selection: 330g acrylate resin, brand LG Chem BF-2410, Mw = 450,000; 52g epoxy resin, brand Olin DER TM 331, epoxy equivalent 182-192g / eq; 250g of photosensitive composition, comprising 62.5g of organosilicon-modified photosensitive prepolymer of Preparation Example 2, 112.5g of hydroxyethyl methacrylate, 37.5g of neopentyl glycol diacrylate, and 37.5g of ethoxylated trimethylolpropane triacrylate; antistatic agent ( N20 ethoxylated alkylamine) 5g; curing agent (HexionEPIKURE TM 3115 anhydride) 5g; photoinitiator (BASF 907) 7.5g; solvent (ethyl acetate:propylene glycol methyl ether = 1:1) 160g.

[0073] Acrylate resin, epoxy resin, photosensitive composition, antistatic agent and 80wt% solvent are added to a reactor and stirred for 1 hour; in the dark, photoinitiator and 10wt% solvent are mixed evenly and added to the reactor, mixed and stirred for 20 minutes, and finally, curing agent and remaining solvent are mixed and added to the stirring kettle, mixed and stirred for 20 minutes to prepare UV viscosity-reducing adhesive.

[0074] Use a coating machine to apply UV adhesive to a 50µm thick PO substrate. After coating, place the substrate in a 100°C oven for 1.5 minutes. After drying, the film thickness is approximately 20±2µm. A PET light release film is attached to the dried UV adhesive and cured at 60°C for 72 hours to obtain a film suitable for wafer dicing.

[0075] Example 3, a wafer dicing adhesive reduction film is prepared according to the following steps:

[0076] Raw material selection: 330g acrylate resin, brand BASF S790, Mw = 750,000; 52g epoxy resin, brand Hexion EPON TM 1001F, epoxy equivalent 450-500g / eq; 350g of photosensitive composition, comprising 157.5g of organosilicon-modified photosensitive prepolymer of Preparation Example 3, 96.25g of ethoxyethyl acrylate, 57.75g of tripropylene glycol diacrylate, 38.5g of dipentaerythritol hexaacrylate; antistatic agent (Agfa S315 polythiophene) 20g; curing agent (Huntsman D-230 polyetheramine) 8g; photoinitiator (IGM TPO+184, mass ratio 2:1) 15g; solvent (cyclohexanone: xylene = 1:1) 220g.

[0077] Acrylate resin, epoxy resin, photosensitive composition, antistatic agent and 80wt% solvent are added to a reactor and stirred for 2h; photoinitiator and 10wt% solvent are mixed evenly and added to the reactor under light protection, mixed and stirred for 40min, and finally curing agent and remaining solvent are mixed and added to the stirring kettle, mixed and stirred for 30min to prepare UV viscosity-reducing adhesive.

[0078] Use a coating machine to scrape the UV anti-viscosity adhesive onto a 50um thick PO substrate. After coating, place it in a 100℃ oven and bake for 2 minutes. After drying, the thickness of the film is about 20±2um. Then use a flat film laminating machine to attach the release film. Select the release surface of the PET light release film and attach it to the dried UV anti-viscosity adhesive. Curing at 60℃ for 48h will obtain the anti-viscosity film for wafer cutting.

[0079] Example 4 is a viscous film for wafer dicing. The difference from Example 1 is that the organosilicon-modified photosensitive prepolymer of Preparation Example 1 is replaced by an equal amount of the organosilicon-modified photosensitive prepolymer of Preparation Example 4.

[0080] Example 5 is a viscous film for wafer dicing. The difference from Example 1 is that the organosilicon-modified photosensitive prepolymer of Preparation Example 1 is replaced by an equal amount of the organosilicon-modified photosensitive prepolymer of Preparation Example 5.

[0081] Example 6 is a viscous film for wafer dicing. The difference from Example 1 is that the organosilicon-modified photosensitive prepolymer of Preparation Example 1 is replaced by an equal amount of the organosilicon-modified photosensitive prepolymer of Preparation Example 6.

[0082] Comparative Example

[0083] Comparative Example 1 is a viscous film for wafer dicing, which differs from Example 6 in that the organosilicon-modified photosensitive prepolymer of Preparation Example 1 is replaced by an equal amount of the organosilicon-modified photosensitive prepolymer of Preparation Example 7.

[0084] Comparative Example 2 is a viscous film for wafer dicing, which differs from Example 6 in that the organosilicon-modified photosensitive prepolymer of Preparation Example 1 is replaced by an equal amount of the organosilicon-modified photosensitive prepolymer of Preparation Example 8.

[0085] Comparative Example 3, a viscous film for wafer dicing, differs from Example 6 in that the organosilicon-modified photosensitive prepolymer of Preparation Example 1 is replaced by an equal amount of the organosilicon-modified photosensitive prepolymer of Preparation Example 9.

[0086] Comparative Example 4, a viscosity-reducing film for wafer dicing, differs from Example 6 in that no silicone-modified photosensitive prepolymer is added to the photosensitive composition, and its composition is: 145 g of butyl acrylate, 72.5 g of 1,6-hexanediol diacrylate, and 72.5 g of pentaerythritol triacrylate.

[0087] Performance testing

[0088] Test 1: Peel strength test

[0089] Test method:

[0090] Sample Preparation: Cut a sample of the adhesive-reducing film (25 mm wide x 150 mm long) and remove the release film. Apply the sample to a cleaned silicon wafer (775 μm thick, surface roughness Ra ≤ 0.2 μm) and a glass substrate (slide). Press the sample together using a 2 kg rubber roller at a speed of 300 mm / min, three times. Allow the sample to rest for 20 minutes (23 ± 2°C, 50 ± 5% RH).

[0091] Before UV peeling force: Using a tensile testing machine (Instron 34SC1), with a clamp spacing of 50mm, a peeling angle of 180°, and a speed of 300mm / min. The average value of 10 data points within the peeling stable section (250mm) was taken. After UV peeling force: Irradiation conditions: 365nm UV light source (70-100mW / cm 2 ), energy 5J / cm 2 , nitrogen protection (O2 ≤ 0.2%). After irradiation, let it stand for 20 minutes, test the peeling strength under the same conditions, and observe whether there is any residual adhesive during the peeling process.

[0092] Test 2: Anti-migration and precipitation performance test

[0093] Sample Preparation: Cut a sample of the adhesive-reducing film (25 mm wide x 150 mm long) and remove the release film. Apply the sample to a cleaned silicon wafer (775 μm thick, surface roughness Ra ≤ 0.2 μm) and a glass substrate (slide). Press the sample together using a 2 kg rubber roller at a speed of 300 mm / min, three times. Allow the sample to rest for 20 minutes (23 ± 2°C, 50 ± 5% RH).

[0094] Test method: Place the wafer-attached sample in a 70°C oven for 3 hours, then take it out and cool it to room temperature. Test the post-UV peel strength according to the steps in Test 1 above, and observe whether there is any residual adhesive during the peeling process.

[0095] Table 1. Performance test results

[0096]

[0097] Analysis of test results:

[0098] As can be seen from the above table, the post-UV peel strength of Examples 1-3 is ≤5.2gf / 25mm, which is significantly lower than the threshold value of 10gf / 25mm. The post-UV peel strength of Comparative Examples 1-4 is 12.3~35.6gf / 25mm. Regarding the threshold value of 10gf / 25mm, there is a film residue phenomenon after peeling. The reason may be that the silicone prepolymer forms a continuous weak interface layer after UV, which helps to reduce the post-UV peel strength of the viscosity-reducing film. In addition, it can be seen from Comparative Example 3 that the pre-UV peel strength of the photosensitive prepolymer without the introduction of silicone segments is reduced, indicating that the silicone-modified photosensitive prepolymer of the present application helps to improve its adhesion to the viscosity-reducing film and the substrate by grafting hydrogenated siloxane.

[0099] After aging, the peel strength of Examples 1-3 remained below the threshold of 10 gf / 25 mm, and no adhesive residue was observed. However, the peel strength of Example 6 and Comparative Examples 1-4 increased significantly after aging, but adhesive film residue was observed. This may be due to the cross-linked network created by the polyisocyanate, which effectively prevented small molecules from migrating to the interface, causing "re-adhesion" and adhesive residue.

[0100] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, 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 UV viscosity-reducing adhesive, characterized in that: Contains the following raw materials in parts by weight: 20-40 parts of acrylate resin, 5-10 parts of epoxy resin, 20-35 parts of photosensitive composition, 0.5-2 parts of antistatic agent, 0.5-1 part of curing agent, 0.5-1.5 parts of photoinitiator, and 15-25 parts of solvent; the photosensitive composition comprises a photosensitive monomer and an organosilicon-modified photosensitive prepolymer, wherein the organosilicon-modified photosensitive prepolymer accounts for 20-50 wt%; The raw materials of the organosilicon-modified photosensitive prepolymer include acrylate monomers and hydrogen-containing siloxanes, which are subjected to hydrosilylation under a platinum catalyst, and the molar ratio of the alkenyl group in the acrylate monomer to the hydrogen group in the hydrogen-containing siloxane is 1:(0.4-0.6); the functionality of the acrylate monomer is not less than 2.

2. The UV viscosity reducing adhesive according to claim 1, characterized in that: The acrylate monomer is any one or more of pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipropylene glycol ester, and ethoxylated pentaerythritol tetraacrylate.

3. The UV viscosity reducing adhesive according to claim 1, characterized in that: The hydrogen-containing siloxane is selected from any one or more of trimethoxysilane, triethoxysilane, methyldimethoxysilane and ethyldimethoxysilane.

4. The UV viscosity-reducing adhesive according to claim 2, characterized in that: The raw materials of the organosilicon-modified photosensitive prepolymer include polyisocyanate, the polyisocyanate and the reaction product of hydrosilylation are subjected to addition polymerization, and the molar ratio of the hydroxyl group in the acrylate monomer to the isocyanate group in the polyisocyanate is 1:(0.5-0.6).

5. The UV viscosity-reducing adhesive according to claim 4, characterized in that: The polyisocyanate is an aliphatic polyisocyanate.

6. The UV viscosity-reducing adhesive according to claim 1, characterized in that: The photosensitive monomers are selected from monofunctional monomers, difunctional monomers and multifunctional monomers in a mass ratio of 3-5:1-3:1-2.

7. The UV viscosity reducing adhesive according to claim 1, characterized in that: The antistatic agent is selected from any one or more of polythiophene derivatives, polyaniline derivatives, ethoxylated aliphatic alkylamines, graphene and its derivatives, carbon black, and lithium sulfonate salts.

8. The UV viscosity reducing adhesive according to claim 1, characterized in that: The epoxy equivalent of the epoxy resin is 100 to 500 g / eg.

9. A method for preparing a UV viscosity-reducing adhesive, characterized in that: According to the UV viscosity-reducing adhesive ratio described in any one of claims 1 to 8, acrylate resin, epoxy resin, photosensitive composition, antistatic agent and solvent are mixed to obtain a mixture; photoinitiator is added to the mixture in the dark, and finally a curing agent is added and stirred evenly to obtain the mixture.

10. A wafer dicing adhesive reduction film, characterized in that: The invention comprises a substrate, the UV viscosity-reducing adhesive according to any one of claims 1 to 8, and a release film which are stacked in sequence.

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