Non-uv wafer bg thinning adhesive tape and preparation method thereof

Abstract

The application relates to the technical field of adhesives, and specifically discloses a non-UV wafer BG thinning adhesive tape and a preparation method thereof. The non-UV wafer BG thinning adhesive tape comprises a substrate layer, a buffer adhesive layer and a release film layer; the buffer adhesive layer is prepared from the following raw materials in parts by mass: 60-70 parts of soft monomers, 15-25 parts of high-Tg hard monomers, 1.5-3 parts of bifunctional acrylate monomers, 4-7.5 parts of functional monomers, 3-4 parts of silanized nano calcium carbonate, 2.5-4.0 parts of isocyanate cross-linking agents, 0.6-0.8 parts of initiators, 0.2-0.4 parts of antioxidants and 80-120 parts of solvents; the functional monomers comprise epoxy acrylate and acrylic monomers; and the high-Tg hard monomers comprise isobornyl methacrylate and hard monomer A. The non-UV wafer BG thinning adhesive tape prepared by the application has the advantages of high thinning precision, clean peeling without residual adhesive and stable substrate supporting performance.

Description

Technical Field

[0001] This application relates to the technical field of adhesives, and more specifically, to a non-UV wafer BG thinning tape and its preparation method. Background Technology

[0002] As semiconductor chip packaging evolves towards thinner, thinner, higher-density, and more integrated designs, back-grinding (BG) has become a core process in back-end packaging. This process requires reducing the wafer thickness after front-side circuit fabrication from 750-800 μm to 50-150 μm to meet the process requirements of chip stacking and miniaturization. Wafer thinning is mostly achieved through mechanical grinding, which offers advantages such as high processing efficiency and low mass production costs. However, the grinding process generates severe mechanical vibrations, continuous high shear stress, and localized high temperatures. This not only easily leads to problems such as wafer warping, microcracks, and breakage, but also causes uneven grinding within the wafer surface, ultimately resulting in a high total thickness variation (TTV), which fails to meet the high-precision thinning requirements of advanced packaging.

[0003] To avoid these problems, the industry typically applies BG (Balanced Grinding) tape to the front side of wafers, providing stable physical support, interface sealing, and anti-contamination protection. Wafer thinning tapes are mainly divided into two categories: UV-cured and non-UV-cured. Non-UV tapes are traditional pressure-sensitive tapes; considering ease of peeling, their adhesion is generally lower than UV-cured tapes. Compared to UV-cured tapes, non-UV tapes do not require UV curing equipment, are ready to use immediately, and have greater process compatibility. They are irreplaceable in semiconductor devices intrinsically sensitive to ultraviolet light, high-temperature back-end processes for power devices, production lines without UV equipment, and DBG pre-cutting and post-grinding processes.

[0004] Patent application CN121045980A discloses a semiconductor wafer thinning tape, comprising a substrate layer and an adhesive layer disposed on the surface of the substrate layer. The substrate layer is made of polyolefin, and the adhesive layer is a modified acrylic adhesive layer. The modified acrylic adhesive layer comprises the following raw materials in parts by weight: 60-70 parts of isooctyl acrylate, 15-25 parts of butyl acrylate, 5-10 parts of methyl methacrylate, 2-5 parts of hydroxyethyl acrylate, 0.5-2 parts of glycidyl methacrylate, 1-3 parts of modifier, 0.8-1.2 parts of isocyanate crosslinking agent, 0.3-0.8 parts of epoxy crosslinking agent, and 0.3-0.8 parts of azobisisobutyronitrile.

[0005] In this technical solution, the modified acrylic adhesive layer uses a high proportion of soft monomers, coupled with a severe deficiency of hard monomers and a low amount of crosslinking agent. This results in the inability to form a dense and uniform crosslinking network, leading to a significantly low crosslinking density in the adhesive layer and severely insufficient cohesion. Under the high shear stress and high temperature conditions of wafer mechanical polishing, the low-cohesion adhesive layer is prone to interface slippage, local creep, or cohesive failure, causing relative displacement between the tape and the wafer. This results in significant deviations in the amount of polishing done at various points on the wafer surface, ultimately manifesting as a severe decrease in polishing uniformity and a significant increase in wafer TTV. Summary of the Invention

[0006] To address the issues of decreased grinding uniformity and high TTV in wafer thinning in existing technologies, this application provides a non-UV wafer BG thinning tape and its preparation method.

[0007] In a first aspect, this application provides a non-UV wafer BG thinning tape, which adopts the following technical solution:

[0008] A non-UV wafer BG thinning tape includes a substrate layer, a buffer adhesive layer, and a release film layer. The buffer adhesive layer is made of the following raw materials in parts by weight: 60-70 parts soft monomer, 15-25 parts high Tg hard monomer, 1.5-3 parts bifunctional acrylate monomer, 4-7.5 parts functional monomer, 3-4 parts silanized nano-calcium carbonate, 2.5-4.0 parts isocyanate crosslinking agent, 0.6-0.8 parts initiator, 0.2-0.4 parts antioxidant, and 80-120 parts solvent. The functional monomer includes epoxy acrylate and acrylic monomer. The high Tg hard monomer includes isobornyl methacrylate and hard monomer A.

[0009] In this technical solution, a soft monomer is used as the matrix to provide the basic flexibility and wafer adhesion of the adhesive layer. A complementary rigid molecular framework and steric hindrance physical cross-linking micro-regions are constructed by compounding isoborneol methacrylate with hard monomer A. The pre-cross-linking of bifunctional acrylate monomers and the post-cross-linking of isocyanate form a dense and uniform chemical cross-linking network. Functional monomers ensure sufficient cross-linking, and silanized nano-calcium carbonate enhances interfacial bonding and deformation resistance. The multi-system synergistically improves the cohesion, high-temperature creep resistance and dimensional stability of the adhesive layer, prevents adhesive layer slippage and local deformation during grinding, ensures a high degree of uniform grinding amount on the wafer surface, and leaves no adhesive residue after peeling.

[0010] Furthermore, the mass ratio of isobornyl methacrylate to hard monomer A is 1:(0.5~1.5).

[0011] In this technical solution, the large alicyclic isoborneol group of isoborneol methacrylate provides strong steric hindrance, forming stable physically cross-linked microdomains in the molecular chain without improving the permanent adhesion of the adhesive layer, ensuring easy subsequent peeling; hard monomer A provides a conjugated / polar rigid molecular skeleton, supplementing and improving the high-temperature modulus and heat resistance of the adhesive layer. The two work synergistically to significantly improve the cohesive strength and creep resistance under high-temperature and high-shear conditions without sacrificing the initial tack, flexibility and adhesion of the adhesive layer provided by the soft monomer.

[0012] Furthermore, the soft monomer is selected from at least one of isooctyl acrylate and butyl acrylate.

[0013] In this technical solution, the soft monomer and the high Tg hard monomer form a molecular chain structure with a rigid-flexible balance. While ensuring pressure-sensitive adhesive performance, it provides a suitable chain segment basis for the crosslinking network to play an anti-shear and anti-creep role, ensuring uniform bonding across the entire wafer surface and stable TTV control effect.

[0014] Furthermore, the hard monomer A is selected from at least one of methyl methacrylate and styrene.

[0015] Furthermore, the hard monomer A is styrene.

[0016] Furthermore, the bifunctional acrylate monomer is selected from at least one of 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, and polyethylene glycol diacrylate.

[0017] In this technical solution, the bifunctional acrylate monomers construct a uniform pre-crosslinked network during the polymerization stage, providing uniform chemical anchors for subsequent crosslinking, improving the density and uniformity of the crosslinked network, enhancing the cohesive strength and dimensional stability of the adhesive layer under high temperature and high shear conditions, eliminating local displacement during grinding, and ensuring uniform thickness reduction.

[0018] Furthermore, the polyethylene glycol diacrylate is polyethylene glycol 400 diacrylate.

[0019] Furthermore, the functional monomer also includes boron- or phosphorus-containing polymerizable monomers.

[0020] Furthermore, in the functional monomer, the mass ratio of epoxy acrylate to acrylic monomer is 1:(1.5~2).

[0021] Furthermore, in the functional monomer, the mass percentage of the boron-containing / phosphorus-containing polymerizable monomer is 15% to 20%.

[0022] Furthermore, the epoxy acrylate is selected from glycidyl methacrylate and glycidyl acrylate.

[0023] Furthermore, the boron-containing / phosphorus-containing polymerizable monomer is selected from at least one of hydroxyethyl methacrylate phosphate and phenolic 4-borate methacrylate.

[0024] Furthermore, the acrylic monomer is selected from at least one of acrylic acid and methacrylic acid.

[0025] In this technical solution, epoxy acrylate and acrylic monomers provide cross-linking reaction sites, constructing supplementary cross-linking nodes and increasing the cross-linking network density; boron-containing / phosphorus-containing polymerizable monomers are directly integrated into the polymer backbone through double bonds, achieving uniform internal catalysis of the cross-linking reaction without the risk of small molecule migration, while enhancing the interfacial bonding force between the adhesive layer and the wafer and substrate, eliminating local delamination and slippage, and further narrowing the wafer thickness deviation.

[0026] Furthermore, the isocyanate crosslinking agent is selected from at least one of hexamethylene diisocyanate trimer and toluene diisocyanate trimer.

[0027] Furthermore, the solvent is ethyl acetate.

[0028] Furthermore, the initiator is azobisisobutyronitrile.

[0029] Furthermore, the antioxidants include antioxidant 1010 and antioxidant 168.

[0030] Furthermore, the buffer adhesive layer also includes 3 to 5 parts by weight of epoxy resin.

[0031] Furthermore, the epoxy resin is bisphenol A type epoxy resin E-51.

[0032] In this technical solution, epoxy resin and acrylate polymer form an interpenetrating network, which improves the high-temperature modulus and structural density of the adhesive layer without affecting its flexibility and peel performance, inhibits the softening and creep of the adhesive layer under high grinding temperature, further improves the stability of TTV control, and reduces the risk of residual adhesive.

[0033] Furthermore, the method for preparing the substrate layer includes the following steps:

[0034] Ethylene-vinyl acetate copolymer, metallocene linear low-density polyethylene, and silanized nano-silica are mixed and then melt-co-extruded at 160~190℃ using a twin-screw extruder. The mixture is then cast into sheets, biaxially stretched, heat-set, corona-treated, and wound up to obtain the substrate layer.

[0035] Furthermore, the mass ratio of the ethylene-vinyl acetate copolymer, metallocene linear low-density polyethylene, and silanized nano-silica is (60~80):(10~30):10.

[0036] In this technical solution, ethylene-vinyl acetate copolymer is used as the main body, combined with metallocene linear low-density polyethylene to form a rigid and flexible substrate matrix with excellent impact resistance and cushioning performance; silanized nano-silica reduces the thermal expansion coefficient of the substrate, reduces thermal mismatch with silicon wafers, and avoids thermal stress warping and local grinding deviations under high grinding temperatures; biaxial stretching and corona treatment optimize the mechanical properties of the substrate, improve the interfacial adhesion with the cushioning adhesive layer, provide stable substrate support for the adhesive layer, and ensure the uniformity of the thinning thickness from the substrate level.

[0037] Furthermore, in the ethylene-vinyl acetate copolymer, the content of vinyl acetate is 5wt%~20wt%.

[0038] Furthermore, in the ethylene-vinyl acetate copolymer, the content of vinyl acetate is 15wt%~20wt%.

[0039] Furthermore, the method for preparing the silanized nano-silica includes the following steps:

[0040] An aqueous solution of nano-silica and silane coupling agent in ethanol was added to a reactor, the pH was adjusted to 8.5-9.0, the temperature was raised to 50-65℃, the reaction was carried out for 2-4 hours, cooled, centrifuged, washed, and dried to obtain silanized nano-silica.

[0041] Furthermore, the particle size distribution of the nano-silica is 10~50nm.

[0042] Secondly, this application provides a method for preparing a non-UV wafer BG thinning tape, comprising the following steps:

[0043] S1: Under an inert atmosphere, mix the soft monomer, high Tg hard monomer, bifunctional acrylate monomer, functional monomer, silanized nano calcium carbonate, initiator and solvent according to the formula, heat to 70~80℃, react for 2~4h, cool, add isocyanate crosslinking agent and antioxidant, mix well, adjust the solid content to obtain the adhesive solution.

[0044] S2: Apply the adhesive evenly to one side of the substrate layer, and dry it at 80~120℃ for 7~10 minutes in a gradient to obtain the buffer adhesive layer;

[0045] S3: The release film is laminated onto the buffer adhesive layer and cured at 40~50℃ for 36~60h to obtain the non-UV wafer BG thinning tape.

[0046] In this technical solution, a uniform pre-crosslinked network is constructed simultaneously during the prepolymerization stage. After cooling, a crosslinking agent is added to prevent the adhesive from gelling and ensure coating stability. Gradient drying avoids defects such as pinholes and uneven thickness in the adhesive layer. Constant temperature curing ensures that the crosslinking reaction is fully completed and the adhesive layer performance is stable.

[0047] Furthermore, the thickness of the buffer adhesive layer is 20~50μm.

[0048] Furthermore, the thickness of the buffer adhesive layer is 20~30μm.

[0049] Furthermore, the release film is a single-sided fluorine release PET film with a thickness of 25~50μm.

[0050] Furthermore, in S2, the coating is applied using a micro-recessed coating technique.

[0051] Furthermore, the micro-grooving process involves transferring the adhesive solution from a micro-grooving roller to the substrate layer via a doctor blade after being quantitatively applied.

[0052] Furthermore, in step S1, after adding the bifunctional acrylate monomer, the step of adding an epoxy resin is also included.

[0053] In summary, this application has the following beneficial effects:

[0054] This application uses isobornyl methacrylate and hard monomer A to construct a rigid molecular framework. The dual dense cross-linked network formed by pre-cross-linking of the bifunctional monomer and post-cross-linking of isocyanate reduces the slippage and local deformation of the adhesive layer during wafer grinding, thus meeting the requirements of high-precision thinning process. Detailed Implementation

[0055] The present application will be further described in detail below with reference to the embodiments.

[0056] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0057] Metallocene linear low-density polyethylene has a weight-average molecular weight to number-average molecular weight ratio (polydispersity index, PDI) of 2.0 to 2.5.

[0058] Preparation Examples 1-3 Substrate Layers

[0059] Preparation Example 1

[0060] The method for preparing the substrate layer in this preparation example includes the following steps:

[0061] Ethylene-vinyl acetate copolymer (vinyl acetate content 15 wt%), metallocene linear low-density polyethylene, and silanized nano-silica were mixed in a high-speed mixer at a mass ratio of 60:30:10 for 5 min. The mixture was then melt-co-extruded through a twin-screw extruder. The melt was extruded through a T-die and cast onto a 35°C quench roll. After preheating at 110°C, the film was biaxially stretched to a thickness of 120 ± 3 μm. After heat setting at 125°C for 45 s, the film surface was subjected to online corona treatment at a power density of 30 W·min / m². 2The substrate surface dyne value is increased to 42mN / m, and then the substrate layer is obtained by winding.

[0062] The parameters for the twin-screw extruder are as follows: Zone 1 temperature 160℃, Zone 2 temperature 170℃, Zone 3 temperature 180℃, and Zone 4 and T-die temperature 190℃.

[0063] The preparation method of silanized nano-silica includes the following steps:

[0064] 10-50 nm nano-silica and 3% by mass of silane coupling agent KH550 ethanol aqueous solution (ethanol volume fraction of 90%) were added to a reactor at a solid-liquid ratio of 1 g: 5 mL. The pH of the system was adjusted to 8.5 with 5% by mass ammonia. The temperature was raised to 50 °C and the reaction was carried out for 4 h. After cooling to room temperature, the mixture was centrifuged, washed twice with deionized water, and dried at 60 °C to constant weight to obtain silanized nano-silica.

[0065] Preparation Example 2

[0066] The method for preparing the substrate layer in this preparation example includes the following steps:

[0067] An ethylene-vinyl acetate copolymer (vinyl acetate content 15 wt%), metallocene linear low-density polyethylene, and silanized nano-silica were mixed in a high-speed mixer at a mass ratio of 80:10:10 and mixed for 5 min. The mixture was then melt-co-extruded using a twin-screw extruder. The melt was extruded through a T-die and cast onto a 35°C quench roll. After preheating at 110°C, the film was biaxially stretched to a thickness of 120 ± 3 μm. After heat setting at 125°C for 45 s, the film surface was subjected to online corona treatment at a power density of 30 W·min / m². 2 The substrate surface dyne value is increased to 42mN / m, and then the substrate layer is obtained by winding.

[0068] The parameters for the twin-screw extruder are as follows: Zone 1 temperature 160℃, Zone 2 temperature 170℃, Zone 3 temperature 180℃, and Zone 4 and T-die temperature 190℃.

[0069] The preparation method of silanized nano-silica includes the following steps:

[0070] 10-50 nm nano-silica and 3% by mass of silane coupling agent KH550 ethanol aqueous solution (ethanol volume fraction of 90%) were added to a reactor at a solid-liquid ratio of 1 g: 5 mL. The pH of the system was adjusted to 8.5 with 5% by mass ammonia. The temperature was raised to 50 °C and the reaction was carried out for 4 h. After cooling to room temperature, the mixture was centrifuged, washed twice with deionized water, and dried at 60 °C to constant weight to obtain silanized nano-silica.

[0071] Preparation Example 3

[0072] The method for preparing the substrate layer in this preparation example includes the following steps:

[0073] An ethylene-vinyl acetate copolymer (vinyl acetate content 20 wt%), metallocene linear low-density polyethylene, and silanized nano-silica were mixed in a high-speed mixer at a mass ratio of 70:20:10 for 5 min. The mixture was then melt-co-extruded through a twin-screw extruder. The melt was extruded through a T-die and cast onto a 35°C quench roll. After preheating at 110°C, the film was biaxially stretched to a thickness of 120 ± 3 μm. After heat setting at 125°C for 45 s, the film surface was subjected to online corona treatment at a power density of 30 W·min / m². 2 The substrate surface dyne value is increased to 42mN / m, and then the substrate layer is obtained by winding.

[0074] The parameters for the twin-screw extruder are as follows: Zone 1 temperature 160℃, Zone 2 temperature 170℃, Zone 3 temperature 180℃, and Zone 4 and T-die temperature 190℃.

[0075] The preparation method of silanized nano-silica includes the following steps:

[0076] 10-50 nm nano-silica and 5% by mass of silane coupling agent KH550 ethanol aqueous solution (ethanol volume fraction of 90%) were added to the reactor at a solid-liquid ratio of 1 g: 5 mL. The pH of the system was adjusted to 9.0 with 5% by mass of ammonia. The temperature was raised to 65 °C and the reaction was carried out for 2 h. After cooling to room temperature, the mixture was centrifuged, washed twice with deionized water, and dried at 60 °C to constant weight to obtain silanized nano-silica.

[0077] Example 1

[0078] The method for preparing the non-UV wafer BG thinning tape in this embodiment includes the following steps:

[0079] S1: Under a nitrogen atmosphere, 600g of soft monomer, 150g of high Tg hard monomer, 15g of bifunctional acrylate monomer, 40g of functional monomer, 30g of silanized nano-calcium carbonate, 8g of azobisisobutyronitrile and 800g of ethyl acetate are mixed, heated to 70℃ and reacted for 4h. After cooling to room temperature, 25g of hexamethylene diisocyanate trimer and 2g of antioxidant are added and mixed. The solid content is adjusted to 40% with ethyl acetate to obtain the gel solution.

[0080] S2: The liquid on the micro-concave roller is quantitatively coated onto one side of the substrate layer in Preparation Example 1 by a doctor blade, and dried at 80°C for 3 min, 100°C for 2 min, and 120°C for 2 min to obtain a buffer adhesive layer with a thickness of 20 μm.

[0081] S3: A 25μm thick release film is laminated onto a buffer adhesive layer and cured at 40℃ for 48h to obtain a non-UV wafer BG thinning tape.

[0082] The soft monomer is isooctyl acrylate; the high Tg hard monomers are isobornyl methacrylate 75g and methyl methacrylate 75g; the bifunctional acrylate monomer is 1,6-hexanediol diacrylate; the functional monomers are acrylic acid 25g and glycidyl methacrylate 15g; and the antioxidants are antioxidant 1010 1g and antioxidant 168 1g.

[0083] The preparation method of silanized nano-calcium carbonate includes the following steps:

[0084] 10-20 nm nano-calcium carbonate and 5% (w / w) ethanol-water solution of silane coupling agent KH550 (90% by volume of ethanol) were added to a reactor at a solid-liquid ratio of 1 g: 5 mL. The pH of the system was adjusted to 9.5 with 5% (w / w) ammonia. The temperature was raised to 50 °C and the reaction was carried out for 4 h. After cooling to room temperature, the mixture was centrifuged, washed twice with deionized water, and dried at 60 °C to constant weight to obtain silanized nano-calcium carbonate.

[0085] Example 2

[0086] The method for preparing the non-UV wafer BG thinning tape in this embodiment includes the following steps:

[0087] S1: Under a nitrogen atmosphere, 700g of soft monomer, 250g of high Tg hard monomer, 30g of bifunctional acrylate monomer, 60g of functional monomer, 40g of silanized nano-calcium carbonate, 6g of azobisisobutyronitrile and 1200g of ethyl acetate are mixed, heated to 80℃ and reacted for 2h. After cooling to room temperature, 40g of hexamethylene diisocyanate trimer and 4g of antioxidant are added and mixed. The solid content is adjusted to 40% with ethyl acetate to obtain the gel solution.

[0088] S2: The liquid on the micro-concave roller is quantitatively coated onto one side of the substrate layer in Preparation Example 2 by a doctor blade, and dried at 80°C for 4 min, 100°C for 3 min, and 120°C for 3 min to obtain a buffer adhesive layer with a thickness of 30 μm.

[0089] S3: A 25μm thick release film is laminated onto a buffer adhesive layer and cured at 40℃ for 60h to obtain a non-UV wafer BG thinning tape.

[0090] The soft monomers are 600g of isooctyl acrylate and 100g of butyl acrylate; the high Tg hard monomers are 100g of isobornyl methacrylate, 75g of methyl methacrylate and 75g of styrene; the bifunctional acrylate monomers are 15g of 1,6-hexanediol diacrylate and 15g of tripropylene glycol diacrylate; the functional monomers are 40g of acrylic acid and 20g of glycidyl methacrylate; and the antioxidants are 2g of antioxidant 1010 and 2g of antioxidant 168.

[0091] The preparation method of silanized nano-calcium carbonate includes the following steps:

[0092] 10-20 nm nano-calcium carbonate and 3% by mass of silane coupling agent KH550 ethanol aqueous solution (ethanol volume fraction of 90%) were added to the reactor at a solid-liquid ratio of 1 g: 5 mL. The pH of the system was adjusted to 9.0 with 5% by mass ammonia. The temperature was raised to 65 °C and the reaction was carried out for 2 h. After cooling to room temperature, the mixture was centrifuged, washed twice with deionized water, and dried at 60 °C to constant weight to obtain silanized nano-calcium carbonate.

[0093] Example 3

[0094] The method for preparing the non-UV wafer BG thinning tape in this embodiment includes the following steps:

[0095] S1: Under a nitrogen atmosphere, 640g of soft monomer, 220g of high Tg hard monomer, 25g of bifunctional acrylate monomer, 60g of functional monomer, 35g of silanized nano-calcium carbonate, 7.5g of azobisisobutyronitrile and 1000g of ethyl acetate were mixed, heated to 75℃ and reacted for 3h. After cooling to room temperature, 35g of toluene diisocyanate trimer and 4g of antioxidant were added and mixed. The solid content was adjusted to 40% with ethyl acetate to obtain the gel solution.

[0096] S2: The liquid on the micro-concave roller is quantitatively coated onto one side of the substrate layer in Preparation Example 3 by a doctor blade, and dried at 80°C for 4 min, 100°C for 3 min, and 120°C for 3 min to obtain a buffer adhesive layer with a thickness of 30 μm.

[0097] S3: A 50μm thick release film is laminated onto a buffer adhesive layer and cured at 50℃ for 36 hours to obtain a non-UV wafer BG thinning tape.

[0098] The soft monomers are 590g of isooctyl acrylate and 50g of butyl acrylate; the high Tg hard monomers are 145g of isobornyl methacrylate and 75g of styrene; the bifunctional acrylate monomers are 15g of tripropylene glycol diacrylate and 10g of polyethylene glycol 400 diacrylate; the functional monomers are 40g of methacrylic acid and 20g of glycidyl acrylate; and the antioxidants are 2g of antioxidant 1010 and 2g of antioxidant 168.

[0099] The preparation method of silanized nano-calcium carbonate includes the following steps:

[0100] 10-20 nm nano-calcium carbonate and 3% by mass of silane coupling agent KH550 ethanol aqueous solution (ethanol volume fraction of 90%) were added to the reactor at a solid-liquid ratio of 1 g: 5 mL. The pH of the system was adjusted to 9.0 with 5% by mass ammonia. The temperature was raised to 65 °C and the reaction was carried out for 2 h. After cooling to room temperature, the mixture was centrifuged, washed twice with deionized water, and dried at 60 °C to constant weight to obtain silanized nano-calcium carbonate.

[0101] Example 4

[0102] The difference between this embodiment and embodiment 3 is as follows:

[0103] The functional monomers are 30g acrylic acid, 20g glycidyl methacrylate and 10g hydroxyethyl methacrylate phosphate.

[0104] Everything else is the same as in Example 3.

[0105] Example 5

[0106] The difference between this embodiment and embodiment 3 is as follows:

[0107] The functional monomers are 40g acrylic acid, 20g glycidyl methacrylate, 10g hydroxyethyl methacrylate phosphate, and 5g phenolic 4-borate methacrylate, with a total amount of 75g.

[0108] Everything else is the same as in Example 3.

[0109] Example 6

[0110] The difference between this embodiment and embodiment 5 is as follows:

[0111] S1: Under a nitrogen atmosphere, 640g of soft monomer, 220g of high Tg hard monomer, 25g of bifunctional acrylate monomer, 30g of bisphenol A epoxy resin E-51, 75g of functional monomer, 35g of silanized nano calcium carbonate, 7.5g of azobisisobutyronitrile and 1000g of ethyl acetate were mixed, heated to 75℃ and reacted for 3h. After cooling to room temperature, 35g of toluene diisocyanate trimer and 4g of antioxidant were added and mixed. The solid content was adjusted to 40% with ethyl acetate to obtain the adhesive solution.

[0112] The rest is the same as in Example 5.

[0113] Example 7

[0114] The difference between this embodiment and embodiment 6 is that:

[0115] The dosage of bisphenol A type epoxy resin E-51 is 40g;

[0116] The rest is the same as in Example 6.

[0117] Comparative Example 1

[0118] The difference between this comparative example and Example 1 is as follows:

[0119] No bifunctional acrylate monomers were added;

[0120] The others are the same as in Example 1.

[0121] Comparative Example 2

[0122] The difference between this comparative example and Example 1 is as follows:

[0123] The high Tg hard monomer uses only methyl methacrylate, and the amount of methyl methacrylate used is 150g;

[0124] Everything else is the same as in Example 1.

[0125] Performance testing

[0126] 1. The substrate layers prepared in Examples 1-3 were subjected to mechanical property tests, according to GB / T1040.3-2006. Before testing, the substrate film was cut into standard dumbbell shapes, and three parallel specimens were set up for each group. The specimens were placed between the upper and lower clamps of the electronic universal testing machine and stretched uniformly at a tensile speed of 100 mm / min until the specimens broke. Based on the force-displacement data recorded during the test, the tensile strength and elongation of the specimens were calculated, and the arithmetic mean of the three parallel specimens in each group was taken as the final result. The test data are shown in Table 1.

[0127] Table 1. Mechanical property test data of the substrate layers prepared in Examples 1-3

[0128]

[0129] 2. The non-UV wafer BG thinning tapes prepared in Examples 1-7 and Comparative Examples 1-2 were applied to the front side of an 8-inch semiconductor silicon single wafer. The silicon single wafer was then thinned from its original thickness of 750 μm to a target thickness of 100 μm using a wafer grinder. After thinning, the thickness at multiple points on the wafer surface was measured using a non-contact wafer thickness gauge. The difference between the maximum and minimum thickness was taken as the total thickness deviation (TTV). After peeling off the film tape, the presence of residual adhesive on the wafer surface was observed, as shown in Table 2.

[0130] Table 2 Performance test data of non-UV wafer BG thinning tapes prepared in Examples 1-7 and Comparative Examples 1-2

[0131]

[0132] The performance test data in Tables 1 and 2 show that:

[0133] The modified polyolefin substrate prepared in this application has stable and excellent tensile strength and elongation at break in both the transverse and longitudinal directions, which can provide uniform rigid support and buffering performance for the buffer adhesive layer, ensuring the uniformity of stress during the wafer thinning process from the substrate level.

[0134] Example 1 employs a dual hard monomer compound system and a pre-crosslinking design of bifunctional acrylate monomers. Compared with the comparative technical solution, it significantly optimizes the thickness uniformity of wafer thinning and achieves a clean peeling effect with no residue.

[0135] By optimizing the proportion of isoborneol methacrylate and the selection of hard monomer A, Examples 1 and 3 achieved a better complementary effect of rigid structure compared to Example 2, making the wafer more stable in bonding during the grinding process and further improving the thinning uniformity.

[0136] Examples 4-5 introduce boron- or phosphorus-containing polymerizable monomers into the functional monomer system, achieving simultaneous improvement in crosslinking network uniformity and interfacial bonding strength, and continuously optimizing the thickness accuracy of wafer thinning.

[0137] In Examples 6 and 7, bisphenol A type epoxy resin E-51 was compounded into the adhesive layer system to form an interpenetrating network structure with the acrylate polymer, which further improved the high temperature modulus and deformation resistance of the adhesive layer, effectively inhibited the softening and creep of the adhesive layer under high grinding temperature, and finally achieved extremely low total thickness change after wafer thinning, while maintaining clean peeling performance with no adhesive residue throughout the process.

[0138] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A non-UV wafer BG thinning tape, characterized in that, It includes a substrate layer, a buffer adhesive layer, and a release film layer; the buffer adhesive layer is made of the following raw materials in parts by weight: 60-70 parts of soft monomer, 15-25 parts of high Tg hard monomer, 1.5-3 parts of bifunctional acrylate monomer, 4-7.5 parts of functional monomer, 3-4 parts of silanized nano-calcium carbonate, 2.5-4.0 parts of isocyanate crosslinking agent, 0.6-0.8 parts of initiator, 0.2-0.4 parts of antioxidant, and 80-120 parts of solvent; The functional monomers include epoxy acrylates and acrylic monomers; The high Tg hard monomer includes isobornyl methacrylate and hard monomer A, with a mass ratio of isobornyl methacrylate to hard monomer A of 1:(0.5~1.5), and hard monomer A is selected from at least one of methyl methacrylate and styrene; The bifunctional acrylate monomer is selected from at least one of 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, and polyethylene glycol diacrylate.

2. The non-UV wafer BG thinning tape according to claim 1, characterized in that, The functional monomers also include boron- or phosphorus-containing polymerizable monomers.

3. The non-UV wafer BG thinning tape according to claim 2, characterized in that, The boron- or phosphorus-containing polymerizable monomer is selected from at least one of hydroxyethyl methacrylate phosphate and phenolic 4-borate methacrylate.

4. The non-UV wafer BG thinning tape according to claim 1, characterized in that, The buffer layer also includes 3 to 5 parts by weight of epoxy resin.

5. The non-UV wafer BG thinning tape according to claim 1, characterized in that, The method for preparing the substrate layer includes the following steps: Ethylene-vinyl acetate copolymer, metallocene linear low-density polyethylene, and silanized nano-silica are mixed and then melt-co-extruded at 160~190℃ using a twin-screw extruder. The mixture is then cast into sheets, biaxially stretched, heat-set, corona-treated, and wound up to obtain the substrate layer.

6. A method for preparing a non-UV wafer BG thinning tape as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Under an inert atmosphere, mix the soft monomer, high Tg hard monomer, bifunctional acrylate monomer, functional monomer, silanized nano calcium carbonate, initiator and solvent according to the formula, heat to 70~80℃, react for 2~4h, cool, add isocyanate crosslinking agent and antioxidant, mix well, adjust the solid content to obtain the adhesive solution. S2: Apply the adhesive evenly to one side of the substrate layer, and dry it at 80~120℃ for 7~10 minutes in a gradient to obtain the buffer adhesive layer; S3: The release film is laminated onto the buffer adhesive layer and cured at 40~50℃ for 36~60h to obtain the non-UV wafer BG thinning tape.

7. The method for preparing non-UV wafer BG thinning tape according to claim 6, characterized in that, In step S1, after adding the bifunctional acrylate monomer, the step of adding epoxy resin is also included.

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