Wafer cutting protective film adhesive and preparation method thereof

Abstract

The application discloses a kind of wafer cutting protective film adhesive, including the following components: hydrogenated polybutadiene type polyurethane acrylate oligomer, soft monomer, hard monomer, special monomer, initiator, surface modified nano-silica and solvent;Hydrogenated polybutadiene type polyurethane acrylate oligomer accounts for the proportion of adhesive 10~55%, soft monomer accounts for the proportion of adhesive 5~30%, hard monomer accounts for the proportion of adhesive 0.5~10%, special monomer accounts for the proportion of adhesive 0.1~3%, initiator accounts for the proportion of adhesive 0.01~3%, surface modified nano-silica accounts for the proportion of adhesive 0.1~3%, solvent accounts for the proportion of adhesive 20~70%.The protective film prepared by the adhesive of the application has suitable coating viscosity, initial adhesion, better 180° peeling force, elongation and tensile strength, and also has better performance in water resistance, high temperature resistance and high humidity, to ensure the smooth progress of wafer cutting process and improve product yield.

Description

Technical Field

[0001] This invention relates to the field of semiconductor wafer manufacturing. More specifically, this invention relates to an adhesive for wafer dicing protective films and a method for preparing the same. Background Technology

[0002] Semiconductor applications have gradually permeated various industries, with wafers—the key physical material for chip manufacturing—being considered the "foundation" and "soil" of the modern information society. The preparation of a qualified wafer involves eight processes: wafer fabrication, oxidation, photolithography, etching, thin film deposition, interconnection, testing, and packaging. Wafer dicing is the first step in semiconductor back-end packaging, dividing the wafer into individual chips along dicing tracks using mechanical or laser methods. Its core objective is to maximize the protection of the chip's electrical performance and mechanical strength while improving yield, all while achieving efficient dicing. However, in practice, problems often arise such as: 1. High brittleness. The brittleness of wafers increases significantly during the thinning process. The mechanical or thermal stress generated during dicing can cause microcracks, notches, or peeling at the chip edges, known as edge chipping. Edge chipping reduces the mechanical strength of the chip, which may lead to breakage due to stress during subsequent packaging or use. Severe edge cracks can even extend into the internal circuitry of the chip, causing circuit damage or reduced reliability, such as due to humidity corrosion or electromigration.

[0003] 2. Material properties. Modern semiconductor materials are no longer limited to traditional silicon (Si). Gallium arsenide (GaAs), silicon carbide (SiC), and gallium nitride (GaN) are also widely used in semiconductor manufacturing. They have advantages over traditional silicon semiconductors in terms of high frequency, high speed, high voltage, high temperature, high power, and photoelectric conversion efficiency. However, they also have low mechanical strength, are extremely sensitive to stress, are more brittle than silicon, and are more prone to cracking and chipping.

[0004] 3. Miniaturization and Narrow-Track Cutting. As chip size shrinks and integration increases, the blank area left for cutting on the wafer (i.e., the dicing track) becomes narrower and narrower, making it more prone to cracks, damage, and edge chipping. Therefore, the requirements for tools that directly and indirectly assist in cutting are higher.

[0005] 4. Contamination and Cleaning. The dicing process generates contaminants such as silicon chips, dust, and slag. These contaminants may adhere to the chip surface, affecting subsequent pick-up, mounting, and bonding processes, leading to packaging failure. Therefore, an efficient rinsing and cleaning system (such as deionized water and ultrasonic cleaning) is required to ensure the cleanliness of the chips after dicing.

[0006] To address the aforementioned damage and contamination, a "protective film" is often used to fix the wafer during the actual wafer dicing process. It plays three main roles: fixing, protecting, and assisting, which directly affect the dicing yield and subsequent packaging efficiency.

[0007] The purpose of securing the chips is to ensure that thousands of tiny chips remain firmly in their original positions during and after the dicing process, preventing them from moving, scattering, or being lost. This is a prerequisite for the accurate and efficient "pickup" process. If the chips shift, automated equipment will be unable to pick them up precisely. The purpose of protection is twofold: firstly, during dicing, the cooling water (used for cooling, lubrication, and chip removal) and the silicon powder and debris generated are blocked by the protective film, preventing them from contaminating the front-side circuitry of the chip. The front side of the chip contains intricate circuitry manufactured through hundreds of processes, and any contamination could lead to short circuits or decreased reliability. The protective film acts as a temporary "protective shield." Secondly, dicing (especially mechanical blade dicing) generates significant mechanical stress and vibration. The protective film, with its elasticity and viscosity, can absorb and disperse some of this stress, reducing the force transmitted to the chip. This helps reduce the risk of chip edge chipping and back-side cracks, which is especially important for ultra-thin wafers. The auxiliary process refers to the fact that dicing usually involves attaching the wafer to a metal ring to tighten the film and form a stable "film-wafer" assembly. This provides a solid mechanical support platform for dicing, cleaning, transportation, and even subsequent film expansion (to increase the distance between chips for picking) and picking, making it a perfect fit for automated production lines.

[0008] As a crucial auxiliary material in wafer fabrication, the adhesive in the protective film is key! The viscosity of the adhesive should not be too high, otherwise uneven coating will occur during the application process. Initial tack ensures that the wafer remains stable and controlled throughout the entire early and mid-stages from film application to dicing, laying the foundation for high-quality dicing and pick-up. Insufficient initial tack can cause bubbles and edge lifting after film application, wafer displacement and vibration during dicing affecting dicing accuracy, and coolant and dicing debris may seep in through gaps, contaminating the front circuitry of the chip. Conversely, excessive tack increases the risk of residual adhesive removal, and excessive internal stress may exacerbate chipping at the chip edges, thus damaging the wafer. A 180° peel force primarily meets the core "dynamic adhesion" indicator, ensuring strong adhesion during dicing and easy separation during pick-up. High elongation helps the protective film adhere tightly to the back of the wafer (especially when there are circuits or uneven surfaces), reducing bubbles. In the subsequent "film expansion" process, the uniform stretching of the film helps separate the chip, facilitating pick-up. Because some subsequent manufacturing processes involve high temperatures (such as reflow soldering, which can reach 150°C) and cleaning steps, the protective film must maintain its shape and adhesion stability at this temperature, without decomposing or generating additional stress that could cause chip breakage, while also possessing good resistance to high temperatures and humidity. In summary, providing a protective film that simultaneously possesses suitable initial tack, 180° peel strength, elongation, resistance to high temperatures, moisture, and damp heat aging is crucial for wafer manufacturing. Summary of the Invention

[0009] One objective of this invention is to provide an adhesive for wafer dicing protective films and its preparation method. The protective film prepared by the adhesive has suitable coating viscosity and initial tack, good 180° peel strength, elongation and tensile strength, and also has good performance in water resistance, high temperature resistance and high humidity resistance, ensuring the smooth progress of the wafer dicing process and improving product yield.

[0010] To address the aforementioned technical problems, this invention provides an adhesive for wafer dicing protective films, comprising the following components: hydrogenated polybutadiene-type polyurethane acrylate oligomer, soft monomer, hard monomer, special monomer, initiator, surface-modified nano-silica, and solvent; the proportion of hydrogenated polybutadiene-type polyurethane acrylate oligomer in the adhesive is 10-55%, the proportion of soft monomer is 5-30%, the proportion of hard monomer is 0.5-10%, the proportion of special monomer is 0.1-3%, the proportion of initiator is 0.01-3%, the proportion of surface-modified nano-silica is 0.1-3%, and the proportion of solvent is 20-70%.

[0011] Preferably, the hydrogenated polybutadiene-type polyurethane acrylate oligomer is composed of one or more hydrogenated polybutadiene-based polyurethane acrylates. Preferably, the soft monomer is one or a mixture of butyl acrylate, isooctyl acrylate, ethyl acrylate, and lauryl acrylate.

[0012] Preferably, the hard monomer is one or a mixture of methyl methacrylate, ethyl methacrylate, styrene, and acrylic acid.

[0013] Preferably, the special monomer is a fluorinated acrylate, specifically one or a mixture of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, octafluoropentyl acrylate, and trifluoromethyl methacrylate.

[0014] Preferably, the initiator is one or a mixture of TPO, 184, 651, ITX, and EDB; and the solvent is one or a mixture of n-heptane and n-hexane.

[0015] Preferably, the surface-modified nano-silica is nano-silica particles modified with a silane coupling agent.

[0016] This invention also provides a method for preparing an adhesive for wafer dicing protective films. First, soft monomers, hard monomers, special monomers, and initiators are mixed in a proportion and added to a mixing tank. The mixture is then initially stirred at 60°C for 30 minutes. Next, hydrogenated polybutadiene-type polyurethane acrylate oligomer is added to the mixing tank, and the mixture is stirred at 60°C for 1 hour. After standing and cooling to room temperature, a corresponding amount of solvent is added, and the mixture is stirred at room temperature for 30-60 minutes to achieve a homogeneous state. Finally, a corresponding amount of surface-modified nano-silica is added, and the mixture is dispersed and stirred using a high-speed disperser at 1000-1500 rpm for 60-90 minutes.

[0017] The present invention also provides a protective film for wafer dicing, comprising a substrate layer, an adhesive layer, and a release film layer stacked sequentially. The substrate layer is composed of one of polyethylene terephthalate, polyethylene, thermoplastic polyurethane, and polyvinyl chloride. The substrate layer is corona-treated and has a primer coated on the side in contact with the adhesive layer. The thickness of the substrate layer is 70-120 μm. The adhesive layer is formed with the adhesive for wafer dicing protective film as described in any one of claims 1 to 8. The thickness of the adhesive layer is 5-20 μm. The release film layer is made of polyethylene terephthalate and has a thickness of 20-40 μm.

[0018] The present invention also provides a method for preparing a protective film for wafer dicing, wherein an adhesive is applied to one side of a substrate layer that has been corona-treated and has a base coating by spin coating, and dried at 30~80℃ for 10~30 min to allow the solvent to completely evaporate, thereby obtaining an adhesive layer; subsequently, a release film layer is laminated on the adhesive layer to obtain the protective film for wafer dicing.

[0019] The present invention has at least the following beneficial effects: a. Firstly, the saturated carbon-carbon single-bond long chain (without double bonds) of hydrogenated polybutadiene provides excellent aging resistance: such as excellent resistance to thermal oxidation, ultraviolet radiation, and hydrolysis, effectively resisting the swelling and aging of the adhesive layer caused by high temperature and water; secondly, due to the polyurethane connecting segments containing polar groups, the balance between its toughness, adhesion, and cohesive strength can be flexibly adjusted; finally, the acrylate ends carry photocurable carbon-carbon double bonds, which can be rapidly cured into a film by UV light, making it suitable for efficient production.

[0020] b. In addition, the adhesive system is also equipped with a variety of soft, hard and special monomers, which can further optimize the mechanical properties of the system (such as 180° peel force and elongation). Among them, the fluorinated monomers can also further enhance the waterproof and stain-resistant properties of the system. c. After treatment with an organosilane coupling agent, the silanol groups on the surface of the nano-silica react with the coupling agent, while the other end forms chemical bonds or strong interactions with the polymer matrix, forming a robust "particle-matrix" interface. Secondly, the large specific surface area and surface energy cause the polymer molecular chains to be strongly adsorbed onto the nanoparticle surface, forming an interfacial layer. This restricted molecular chain mobility reduces the mobility of the particles, effectively "anchoring" them to the matrix. Therefore, stress can be efficiently transferred from the relatively soft polymer matrix to the high-modulus rigid nanoparticles through this robust interface, preventing debonding and cracking at the interface, thus improving the overall strength and modulus of the material. The high-strength and high-modulus nanoparticles themselves can bear part of the load and disperse concentrated stress points over a larger volume, preventing excessive local stress from causing cutting cracks.

[0021] d. The modified nano-silica surface has abundant double bonds, which can react with acrylate during curing to form covalent bonds that firmly connect the two phases. This lays the chemical basis for the synergistic effect of the solid phase (modified nano-silica) and the liquid phase (hydrogenated polybutadiene-type polyurethane acrylate). The chemical bonding greatly enhances the adhesion between the coating and the wafer, and the dense structure can effectively block the erosion of moisture. In addition, the uniformly dispersed modified nano-silica can simultaneously serve as a physical crosslinking point and a thermal barrier, significantly hindering the thermal motion of polymer molecules at high temperatures. Therefore, the system has good resistance to moisture and high temperatures.

[0022] e. The addition of solvent can effectively reduce the viscosity of the system, providing a wider operating window for practical applications and achieving uniformity of each component in the system, thereby making the various components on the coated adhesive layer more uniform.

[0023] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the wafer dicing protective film of the present invention. Detailed Implementation

[0025] To better understand the purpose, structure, and function of this invention, the invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0026] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] like Figure 1 As shown, the wafer dicing protective film of the present invention is composed of three layers: a substrate layer 1, an adhesive layer 2, and a release film layer 3.

[0028] The substrate layer of the present invention is composed of one of polyethylene terephthalate (PET), polyethylene (PE), thermoplastic polyurethane (TPU), and polyvinyl chloride (PVC). All of the above materials have been corona treated and have a primer applied to the side that is in contact with the adhesive, in order to improve the adhesion between the adhesive layer and the substrate layer. The thickness of the substrate layer is preferably 70~120μm.

[0029] The adhesive layer of the present invention comprises: hydrogenated polybutadiene-type polyurethane acrylate oligomer, soft monomer, hard monomer, special monomer, initiator, surface-modified nano silica and solvent, and the total adhesive layer thickness is preferably 5~20μm.

[0030] The hydrogenated polybutadiene-based polyurethane acrylate oligomer can be composed of one or more hydrogenated polybutadiene-based polyurethane acrylates, with the hydrogenated polybutadiene-based polyurethane acrylate accounting for 10-55% of the adhesive system, preferably 30-50%. The saturated soft segment structure of the hydrogenated polybutadiene-based polyurethane acrylate fundamentally solves the problems of easy hydrolysis, yellowing, and degradation of ordinary polyurethane acrylates due to ester bonds and unsaturated double bonds under high temperature and humidity, perfectly matching the stringent requirements for resistance to high temperature, moisture, and humid heat aging.

[0031] The soft monomer is one or more of butyl acrylate, isooctyl acrylate, ethyl acrylate, and lauryl acrylate. The soft monomer provides flexibility, elasticity, and initial tack in the adhesive, and can reduce the modulus, increase elongation and impact resistance. It accounts for 5-30% of the system, preferably 10-30%.

[0032] The hard monomer is one or more of methyl methacrylate, ethyl methacrylate, styrene and acrylic acid. The hard monomer can provide rigidity, tensile strength, heat resistance, abrasion resistance and adhesion, and accounts for 0.5-10% of the system, preferably 1-5%.

[0033] The special monomer is a fluorinated acrylate, specifically one or a mixture of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, octafluoropentyl acrylate, and trifluoromethyl methacrylate. Fluorinated acrylates have excellent waterproof and stain-resistant properties and account for 0.1-5% of the system, preferably 0.1-3%.

[0034] The initiator is one or more of TPO, 184, 651, ITX, and EDB. The role of the initiator is to generate free radicals under suitable ultraviolet light to initiate the cross-linking polymerization reaction of the system. The initiator accounts for 0.01-3% of the system, preferably 0.1-1%.

[0035] The surface-modified nano-silica is nano-silica particles modified with a silane coupling agent. Its function is to improve the rigidity of the system while maintaining flexibility, strengthen the protective film itself to indirectly protect the wafer, thereby improving the dicing yield. Its proportion in the system is 0.1~3%, preferably 0.1~1%.

[0036] The solvent is one or more of n-heptane and n-hexane. The solvent serves two purposes: firstly, to reduce the viscosity of the system for subsequent coating; and secondly, to enable the components in the formulation to be better miscible into a homogeneous system, which is beneficial to the fullness and completeness of the subsequent reaction. The solvent accounts for 20-70% of the system, preferably 30-60%.

[0037] The release film layer of the present invention is made of polyethylene terephthalate (PET) and the thickness is preferably 20~40μm.

[0038] This invention provides a method for preparing an adhesive for a protective film used in wafer dicing: First, soft monomers, hard monomers, special monomers, and initiators are mixed in proportion and added to a mixing tank, and initially stirred at 60°C for 30 minutes. Then, hydrogenated polybutadiene-type polyurethane acrylate oligomer is added to the mixing tank, and stirring is continued at 60°C for 1 hour. After standing and cooling to room temperature, the corresponding amount of solvent is added, and the mixture is stirred at room temperature for 30-60 minutes to make the system homogeneous. Finally, the corresponding amount of modified nano-silica is added, and the mixture is dispersed and stirred using a high-speed disperser at a speed of 1000-1500 rpm for 60-90 minutes.

[0039] This invention provides a method for preparing a protective film for wafer dicing: an adhesive is applied to a side of a substrate that has been corona-treated and has a base coating by spin coating, and then dried at 30~80℃ for 10~30 min to allow the solvent to completely evaporate, resulting in an adhesive layer; subsequently, a release film layer is laminated onto the adhesive layer to obtain the protective film for wafer dicing.

[0040] The performance testing standards and methods for the adhesives and wafer dicing protective films involved in the embodiments and comparative examples of this invention are as follows: Viscosity: GB / T 21059-2007; Adhesive layer thickness: GB / T 7125-2014; 180° peel strength: GB / T 2792-1998; Elongation: GB / T 1040.1-2006; Initial tack: GB / T 4852-2002; Tensile strength: GB / T 1040.1-2006; High temperature resistance: The protective film is attached to the wafer and a certain force is applied to press it. After placing it in an oven at 150°C for 8 hours, the protective film is peeled off and the wafer surface is observed to see if there is any residual adhesive. Water resistance: The protective film is attached to the wafer and pressed with a certain force. The wafer with the protective film is immersed in pure water for 8 hours at room temperature of 25℃. Observe whether there are any signs of whitening on the surface of the protective film. Resistance to damp heat aging: The protective film is attached to the wafer and pressed with a certain force. After being placed at 25°C for 1 hour, it is placed at 85±2°C and 85±5%RH for 48 hours. Observe whether there are any signs of whitening on the surface of the protective film.

[0041] The commercially available products of each ingredient in the formulation of this example are as follows: Commercial products of hydrogenated polybutadiene polyurethane acrylate: Guangzhou Songda, SD0342 (hydrogenated polybutadiene polyurethane acrylate), SD1002B (polyurethane acrylate).

[0042] Soft monomers: isooctyl acrylate, ethyl acrylate, lauryl acrylate, Aladdin; including but not limited to products of the above companies, and the same substances of other companies may also be used.

[0043] Hard monomers: methyl methacrylate, acrylic acid, aramid; including but not limited to products of the above companies, and the same substances of other companies may also be used.

[0044] Initiators: 184, TPO, 651, Aijianmeng; ITX, EDB, Hubei Gurun; including but not limited to products from the above companies, and the same substances from other companies may also be used.

[0045] Fluorinated monomers: trifluoroethyl methacrylate (Aladdin); hexafluorobutyl methacrylate (Maclean); including but not limited to products of the above companies, and the same substances from other companies may also be used.

[0046] Surface-modified nano-silica: Prepared in the laboratory by modification with silane coupling agent KH570. The long organic chains on the KH570 replace the hydrophilic hydroxyl groups, significantly improving its hydrophobic and oleophilic properties. At the same time, the long-chain organic groups provide steric hindrance, effectively inhibiting agglomeration and significantly improving dispersion. The methacryloyloxy groups (C=C double bonds) successfully grafted onto the surface by KH570 can participate in the polymerization reaction, forming a "chemical bridge" between the particles and the organic matrix, improving compatibility. In addition, the mechanical properties and weather resistance of the material can be stably improved (the hydrophobic surface can form a barrier, effectively reducing water penetration and improving resistance to damp heat).

[0047] Solvents: n-hexane, n-heptane, Aladdin; including but not limited to products of the above companies, and the same substances from other companies may also be used.

[0048] Formulation tables for examples and comparative examples: The performance test results of the adhesive and wafer dicing protective film in the above embodiments and comparative examples are as follows: Note: "○" indicates no residue or no whitening; "◇" indicates a small amount of residue or a whitening area; "×" indicates a large amount of residue or a large whitening area.

[0049] In each embodiment, by using the combination of various components, the adhesive viscosity in the protective film layer is 700~850 mPa·s; the adhesive layer thickness is 10 μm, and it has good initial tack, 180° peel force, and elongation. The initial tack is 10~13#, the 180° peel force is 700~900 g / 25mm, the elongation is 100~190%, and the tensile strength is 30~35 MPa. Wafers were individually attached to protective films and pressed with a certain force. After being placed in an oven at 150°C for 8 hours, the protective films were peeled off, and no adhesive residue was found on the wafer surface. Wafers were individually attached to protective films and pressed with a certain force. After being placed in pure water at room temperature (25°C) for 8 hours, no adhesive residue was found on the protective film surface. Wafers were individually attached to protective films and pressed with a certain force. After being placed at 25°C for 1 hour, they were placed at 85±2°C and 85±5%RH for 48 hours, and no adhesive residue was found on the protective film surface. The wafers exhibit good high temperature resistance, water resistance, and damp heat resistance.

[0050] No hard monomers were added in Comparative Example 1, so the crosslinking density of the protective film adhesive layer was low. Although the initial tack and elongation were good, the 180° peel strength and tensile strength were low, and the high temperature resistance, water resistance and damp heat resistance were poor. In Comparative Example 2, the hydrogenated polybutadiene-type polyurethane acrylate oligomer content is high and the solvent content is low. The viscosity of the adhesive system is too high, and uneven distribution in some areas is easy to occur during coating. Therefore, the initial tack, elongation and water resistance of the adhesive layer are good, but the 180° peel strength and damp heat resistance are average and the high temperature resistance is poor. There is a lot of residual adhesive after peeling. No fluorinated monomers were added in Comparative Example 3, therefore the corresponding protective film adhesive layer had poor water resistance and resistance to damp heat aging. In Comparative Example 4, no surface-modified nano-silica was added, resulting in a weaker system strength. Although the viscosity was suitable and the initial tack, 180° peel strength, and elongation were good, the system performed poorly in terms of high temperature resistance, damp heat aging, and tensile strength, and a small amount of obvious residual adhesive was present.

[0051] Comparative Example 5 used another conventional polyurethane acrylate oligomer instead of hydrogenated polybutadiene polyurethane acrylate. It performed well in terms of viscosity, initial tack and 180° peel strength, but the tensile strength was too high and the elongation was too low. Although it had good high temperature resistance, it had poor resistance in water and humid heat environments and left a lot of residue after glassing.

[0052] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention, and other modifications can be easily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. An adhesive for wafer dicing protective film, characterized in that, The adhesive comprises the following components: hydrogenated polybutadiene-type polyurethane acrylate oligomer, soft monomer, hard monomer, specialty monomer, initiator, surface-modified nano-silica, and solvent; the mass percentages of each component are as follows: hydrogenated polybutadiene-type polyurethane acrylate oligomer accounts for 10-55% of the adhesive, soft monomer accounts for 5-30% of the adhesive, hard monomer accounts for 0.5-10% of the adhesive, specialty monomer accounts for 0.1-3% of the adhesive, initiator accounts for 0.01-3% of the adhesive, surface-modified nano-silica accounts for 0.1-3% of the adhesive, and solvent accounts for 20-70% of the adhesive.

2. The adhesive for wafer dicing protective film as described in claim 1, characterized in that, The hydrogenated polybutadiene-type polyurethane acrylate oligomer is composed of one or more hydrogenated polybutadiene-based polyurethane acrylates.

3. The adhesive for wafer dicing protective film as described in claim 1, characterized in that, The soft monomer is one or a mixture of butyl acrylate, isooctyl acrylate, ethyl acrylate, and lauryl acrylate.

4. The adhesive for wafer dicing protective film as described in claim 1, characterized in that, The hard monomer is one or a mixture of methyl methacrylate, ethyl methacrylate, styrene, and acrylic acid.

5. The adhesive for wafer dicing protective film as described in claim 1, characterized in that, The special monomer is a fluorinated acrylate, specifically one or a mixture of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, octafluoropentyl acrylate, and trifluoromethyl methacrylate.

6. The adhesive for wafer dicing protective film as described in claim 1, characterized in that, The initiator is one or a mixture of TPO, 184, 651, ITX, and EDB; the solvent is one or a mixture of n-heptane and n-hexane.

7. The adhesive for wafer dicing protective film as described in claim 1, characterized in that, The surface-modified nano-silica is nano-silica particles modified with a silane coupling agent.

8. A method for preparing an adhesive for wafer dicing protective film, characterized in that, First, the soft monomer, hard monomer, special monomer, and initiator are mixed in proportion and added to the tank. The mixture is initially stirred at 60°C for 30 minutes. Then, the hydrogenated polybutadiene-type polyurethane acrylate oligomer is added to the tank and stirred at 60°C for 1 hour. After standing and cooling to room temperature, the corresponding amount of solvent is added and stirred at room temperature for 30-60 minutes to make the system homogeneous. Finally, the corresponding amount of surface-modified nano-silica is added and dispersed and stirred at 1000-1500 rpm using a high-speed disperser for 60-90 minutes.

9. A protective film for wafer dicing, characterized in that, The film comprises a substrate layer, an adhesive layer, and a release film layer stacked sequentially. The substrate layer is composed of one of polyethylene terephthalate, polyethylene, thermoplastic polyurethane, and polyvinyl chloride. The substrate layer is corona-treated and has a primer applied to the side in contact with the adhesive layer. The thickness of the substrate layer is 70-120 μm. The adhesive layer is formed using the adhesive for wafer dicing protective film as described in any one of claims 1 to 8. The thickness of the adhesive layer is 5-20 μm. The release film layer is made of polyethylene terephthalate and has a thickness of 20-40 μm.

10. The method for preparing a protective film for wafer dicing as described in claim 9, characterized in that, The adhesive is applied to the side of the substrate layer that has been corona-treated and has a base coating by spin coating, and dried at 30~80℃ for 10~30 minutes to allow the solvent to evaporate completely, thus obtaining an adhesive layer; then a release film layer is laminated on the adhesive layer to obtain the protective film for wafer dicing.

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