Thermosetting hyperbranched temporary bonding adhesive and applications thereof

Abstract

This invention discloses a thermosetting hyperbranched temporary bonding adhesive and its applications. The temporary bonding adhesive comprises a base resin, a reactive diluent, and a curing agent. The base resin comprises a hyperbranched polyacrylate containing multiple epoxy groups. The reactive diluent contains multiple epoxy groups in its structure. The hyperbranched polyacrylate dissolves in the reactive diluent and undergoes a crosslinking reaction under the action of the curing agent. The temporary bonding adhesive of this invention is a reactive solvent type, with no solvent evaporation during curing, forming a dense three-dimensional network that meets the micron-level precision requirements of advanced packaging. The reactive diluent directly participates in the ring-opening copolymerization reaction of the epoxy groups, becoming part of the crosslinking network and combining with the hyperbranched polyacrylate, resulting in high crosslinking density and constructing a chemically resistant barrier. The low shrinkage characteristics of the hyperbranched structure allow for a smooth, low-stress adhesive layer; it exhibits excellent thermal stability after curing and is easy to clean after debonding.

Description

Technical Field

[0001] This invention belongs to the technical field of advanced packaging materials in the semiconductor industry, specifically relating to a thermosetting hyperbranched temporary bonding adhesive and its applications. Background Technology

[0002] The materials required for advanced packaging, such as ABF substrates, photosensitive polyimide, temporary bonding adhesives, underfill adhesives, and silver sintering paste, directly determine the packaging density and reliability, making them a core component of the back-end processes in semiconductor manufacturing. Temporary bonding technology is a core supporting process in advanced packaging fields such as 2.5D / 3D and fan-out designs. It provides reliable bonding and fixation for wafers / chips during high-precision processing, ensuring micron-level processing accuracy, while enabling efficient debonding after the process is completed.

[0003] Existing temporary bonding adhesive materials, whether thermoplastic or thermosetting resins, rely on organic solvents for dissolution and film formation, which has the following significant drawbacks in the field of 2.5D / 3D advanced packaging.

[0004] Firstly, thermoplastic resins exhibit poor chemical resistance and process compatibility, making them unsuitable for the multiple chemical processes involved in advanced packaging. These processes expose the workpiece to concentrated acids (such as hydrofluoric acid and hydrochloric acid), strong alkalis (such as potassium hydroxide solution), polar organic solvents (such as acetone and dimethyl sulfoxide), and plasma environments. Thermoplastic resins lack sufficient resistance to these solvents, especially polar organic solvents, making them prone to swelling or even dissolution failure. This leads to the separation of the adhesive layer from the wafer interface, resulting in decreased strength. Mild cases may cause warping and cracking during wafer thinning, while severe cases can lead to TSV channel blockage and bump oxidation failure, directly impacting packaging yield. Thermosetting resins, due to their insufficient crosslinking density, also suffer from insufficient chemical resistance.

[0005] Secondly, the presence of organic solvents leads to poor film quality even with efficient curing, failing to meet the micron-level precision requirements of advanced packaging. Existing adhesive layer materials dissolve resin polymers in suitable organic solvents. During the heating and film-forming process, the solvent's volatility is utilized to remove it and achieve adhesive layer curing. However, during solvent evaporation and film-forming, it is difficult to balance curing efficiency and film thickness uniformity, easily generating bubbles, pores, and thickness fluctuations. This fails to meet the micron-level precision requirements of thickness deviation <±1μm and roughness <0.5μm, making it unsuitable for subsequent wafer thinning and stacking precision. Furthermore, the pores become channels for chemical reagent penetration.

[0006] Third, insufficient thermal stability prevents them from providing continuous and stable support in advanced packaging processes. Advanced packaging processes include high-temperature annealing (150~250℃) and copper-copper hot-press bonding (200~300℃), requiring temporary bonding adhesives to maintain stable bond strength and structural integrity within this temperature range to prevent softening and degradation of the adhesive layer, which could lead to wafer displacement or damage. Thermoplastic resins rely solely on physical entanglement of molecular chains; excessively high temperatures cause the chain entanglement to fail, resulting in a sharp decrease in bond strength, making them unsuitable for high-temperature processes. While existing thermosetting resins have better heat resistance than thermoplastic resins, their long-term thermal stability is limited by their cross-linking mechanism and molecular structure. Under prolonged exposure to temperatures above 200℃, the cross-linking network is prone to degradation, leading to embrittlement of the adhesive layer, decreased peel strength, and an inability to provide continuous and stable support for the wafer.

[0007] Fourth, it cannot buffer shrinkage stress and differences in thermal expansion, resulting in significant internal stress concentration and warping problems. Traditional thermosetting resin polymers are mostly linear molecular structures. During cross-linking and curing, the regularity of the molecular chain arrangement increases, easily leading to significant volume shrinkage (typically 5-10%). At the same time, their coefficient of thermal expansion is poorly matched with silicon wafers. During the thermal cycling of the packaging process, a significant difference in thermal expansion occurs between the adhesive layer and the wafer, forming large internal stresses. The combination of these factors causes warping deformation of thin wafers, which in turn affects the subsequent bonding alignment accuracy and restricts the realization of sub-micron precision processing.

[0008] In summary, existing temporary bonding adhesive layer materials, due to the limitations of their "organic solvent-dependent curing logic" and molecular structure, are unable to meet the stringent requirements of advanced processes such as high-density stacking, narrow-pitch TSVs, and heterogeneous integration. Summary of the Invention

[0009] The purpose of this invention is to solve the technical problems caused by the use of solvents in existing temporary bonding adhesives. This invention provides a solvent-free thermosetting hyperbranched temporary bonding adhesive and its applications.

[0010] The objective of this invention is achieved through the following technical solution.

[0011] In a first aspect, the present invention provides a thermosetting hyperbranched temporary bonding adhesive, the temporary bonding adhesive comprising a matrix resin, an active diluent, and a curing agent, wherein the matrix resin comprises a hyperbranched polyacrylate containing multiple epoxy groups, the active diluent contains multiple epoxy groups in its structure, and the hyperbranched polyacrylate is dissolved in the active diluent and can undergo a crosslinking reaction under the action of the curing agent.

[0012] Furthermore, the epoxy groups of the hyperbranched polyacrylate are located on the side groups of its molecular chain, and the epoxy value of the hyperbranched polyacrylate is 0.4~0.6 eq / 100g; and / or, the degree of branching of the hyperbranched polyacrylate is 0.5~0.7; and / or, the weight-average molecular weight of the hyperbranched polyacrylate is 15000~25000g / mol; and / or, the PDI of the hyperbranched polyacrylate is 1.3~1.9; and / or, the glass transition temperature Tg of the hyperbranched polyacrylate is 30℃~50℃.

[0013] Furthermore, the mass ratio of the reactive diluent to the matrix resin is (0.3~0.5):1; and / or, the reactive diluent is selected from at least one of 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, and hydrogenated bisphenol A diglycidyl ether.

[0014] Furthermore, the curing agent is an addition-type curing agent or a catalytic curing agent; and / or, the ratio of the molar number of active groups in the addition-type curing agent to the total molar number of epoxy groups in the matrix resin and the active diluent is (0.85~1.05):1; and / or, the amount of the catalytic curing agent added is 1~3% of the mass of the matrix resin.

[0015] Furthermore, the hyperbranched temporary bonding adhesive also includes polyetherimide, which is 5 wt% to 10 wt% of the mass of epoxy-containing hyperbranched polyacrylate.

[0016] Furthermore, the hyperbranched polyacrylate is obtained by polymerization of epoxy-containing acrylate monomers and regulating monomers using a multifunctional RAFT chain transfer agent.

[0017] Furthermore, the epoxy-containing acrylate monomer is selected from glycidyl methacrylate or glycidyl acrylate, and / or the regulating monomer is selected from at least one of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, isobornyl acrylate, isobornyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, and lauryl acrylate; and / or the multifunctional RAFT chain transfer agent contains multiple thiol groups in its structure.

[0018] Furthermore, the mass of the epoxy-containing acrylate monomer accounts for 60% to 85% of the total mass of the monomer.

[0019] Furthermore, the multifunctional RAFT chain transfer agent is selected from at least one of pentaerythritol tetra(3-mercaptopropionate) and trimethylolpropane tri(3-mercaptopropionate).

[0020] In a second aspect, the present invention provides the application of the thermosetting hyperbranched temporary bonding adhesive as described in the first aspect, wherein the thermosetting hyperbranched temporary bonding adhesive is used in wafer processing to temporarily bond the wafer to a carrier.

[0021] This invention uses a reactive diluent to replace an inert organic solvent and uses epoxy-modified hyperbranched polyacrylate as the matrix resin, resulting in excellent synergistic performance. Compared with the prior art, it has the following beneficial effects.

[0022] 1) The "solvent-free" curing mechanism and hyperbranched three-dimensional network achieve highly dense crosslinking and excellent chemical resistance: The reactive diluent containing multiple epoxy groups does not volatilize during the curing process, but directly participates in the ring-opening copolymerization reaction of the epoxy groups, becoming part of the crosslinking network. This process prevents solvent escape, thus forming a dense three-dimensional network. This dense crosslinking network effectively blocks solvent penetration, resulting in a very small mass change rate (<2.0%) of the temporary bonding adhesive in various chemical reagents. Simultaneously, the hyperbranched polyacrylate has a low-entanglement, highly branched three-dimensional spherical structure with small free volume between its molecular chains, effectively blocking the diffusion and penetration of small-molecule solvents. The combination of these two elements results in high crosslinking density, physically constructing an extremely high chemical corrosion resistance barrier, suitable for advanced encapsulation processes involving multiple chemical steps.

[0023] 2) High film quality, producing a smooth, low-stress adhesive film layer that meets the micron-level precision requirements of advanced packaging: Hyperbranched polyacrylate has an irregular, compact three-dimensional structure with minimal intermolecular entanglement and small molecular chain movement during curing, fundamentally suppressing the generation of internal stress that causes wafer warpage. Simultaneously, hyperbranched polyacrylate exhibits low viscosity and high leveling properties in solution, enabling it to spontaneously form a smoother adhesive film layer during spin coating, with a thickness deviation of <±1μm, resulting in high film quality that meets the micron-level precision requirements of advanced packaging.

[0024] 3) Hyperbranched molecular structures exhibit thermal behavior distinctly different from traditional linear polymers, resulting in high heat resistance and easy cleaning after debonding. The numerous epoxy-active functional groups in hyperbranched polyacrylates lay the foundation for forming a highly cross-linked three-dimensional polymer network. After curing, these epoxy groups endow the material with excellent thermal stability, exhibiting significantly higher thermal decomposition temperatures (all >300℃) and excellent high-temperature shear strength (>25 MPa at 200℃). This provides continuous and stable support in advanced encapsulation processes, maintaining stable bond strength and structural integrity during high-temperature processes, enabling it to withstand short-term high-temperature processes.

[0025] In addition, the unique three-dimensional ellipsoidal structure and inherent low molecular weight chain entanglement of hyperbranched polymers cause the crosslinked network to tend to undergo a decomposition mode closer to "disintegration" than the random "fracture" of traditional linear polymers when reaching the high temperature threshold. This structure-guided decomposition path effectively promotes the decomposition of the network into more low-viscosity small molecule products, thus significantly avoiding the high molecular weight, viscous oligomer residue problem commonly found in the thermal decomposition of linear thermosetting polymers, achieving high heat resistance and easy removal characteristics. Detailed Implementation

[0026] To make the technical problems solved, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the embodiments described herein are only some, not all, of the embodiments of this invention, and are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the protection scope of this invention.

[0027] In a first aspect, the present invention provides a thermosetting hyperbranched temporary bonding adhesive, the temporary bonding adhesive comprising a matrix resin, an active diluent, and a curing agent, wherein the matrix resin comprises a hyperbranched polyacrylate containing multiple epoxy groups, the active diluent contains multiple epoxy groups in its structure, and the hyperbranched polyacrylate is dissolved in the active diluent and can undergo a crosslinking reaction under the action of the curing agent.

[0028] The temporary bonding adhesive in this invention is a reactive solvent-based product. The hyperbranched polyacrylate is soluble in the reactive diluent, and there is no solvent evaporation during the curing process, forming a dense three-dimensional network that meets the micron-level precision requirements of advanced packaging. The reactive diluent directly participates in the ring-opening copolymerization reaction of the epoxy groups, becoming part of the crosslinking network. Combined with the hyperbranched polyacrylate, the high crosslinking density constructs an extremely high chemical corrosion resistance barrier. The epoxy groups in the structure impart excellent thermal stability to the material after curing. The low shrinkage characteristics of the hyperbranched structure result in a smooth, low-stress adhesive layer; it also exhibits high heat resistance and is easy to clean after debonding.

[0029] In some specific embodiments, the epoxy groups of the hyperbranched polyacrylate are located on the side groups of its molecular chain, and the epoxy value of the hyperbranched polyacrylate is 0.4~0.6 eq / 100g, and the degree of branching is 0.5~0.7. Specifically, the epoxy value of the hyperbranched polyacrylate can be 0.4eq / 100g, 0.43eq / 100g, 0.45eq / 100g, 0.47eq / 100g, 0.51eq / 100g, 0.54eq / 100g, 0.57eq / 100g, 0.52eq / 100g, or 0.6eq / 100g, etc.; the degree of branching can be 0.5, 0.54, 0.57, 0.59, 0.62, 0.66, or 0.7, etc.

[0030] In this application, epoxy value refers to the amount of epoxy groups contained in 100g of hyperbranched polyacrylate, mainly used to measure the concentration of reactive epoxy groups in hyperbranched polyacrylate. Branching degree refers to the density of branching points in the topological structure of the polymer molecule itself before curing, characterizing its inherent three-dimensional structure and directly affecting its rheological properties and characteristics as a crosslinking precursor. A higher epoxy value ensures a greater number of reactive sites. When the resin reacts with the curing agent, the epoxy groups are transformed into stable chemical crosslinking points, forming a three-dimensional network. The crosslinking density (i.e., the number of crosslinking points per unit volume) ultimately determines the key properties of the cured material, such as mechanical strength, heat resistance, and solvent resistance.

[0031] By adjusting the feed ratio of the monomers and the amounts of RAFT reagent and initiator, the weight-average molecular weight, branching degree, and epoxy value of the obtained hyperbranched polyacrylate can be controlled within the target range, with an epoxy value of 0.4~0.6 eq / 100g, ensuring that the hyperbranched polyacrylate has sufficient and uniformly distributed reactive epoxy groups.

[0032] In some specific embodiments, the weight-average molecular weight of the hyperbranched polyacrylate is 15,000~25,000 g / mol, and the dispersion index (PDI) is 1.3~1.9. Specifically, the weight-average molecular weight of the hyperbranched polyacrylate can be 15,000 g / mol, 16,500 g / mol, 17,200 g / mol, 18,500 g / mol, 20,000 g / mol, 21,000 g / mol, 22,000 g / mol, 23,500 g / mol, or 25,000 g / mol, etc.; and the PDI can be 1.3, 1.35, 1.40, 1.46, 1.50, 1.58, 1.65, 1.71, 1.79, 1.85, or 1.9, etc. A molecular weight that is too low will result in insufficient polymer network strength, while a molecular weight that is too high will affect the solubility of the resin matrix in reactive diluents. A dispersion factor (PDI) of 1.3 to 1.9 is beneficial for ensuring the stability and performance repeatability of products between batches.

[0033] In some specific embodiments, the mass ratio of the reactive diluent to the matrix resin is (0.3~0.5):1. If there is too little reactive diluent, the viscosity of the temporary bonding adhesive precursor will be too high or even incompletely dissolved, making spin coating impossible at the preferred rotation speed; it may even cause insufficient leveling due to excessive viscosity, failing to meet normal processing requirements. If there is too much reactive diluent, the viscosity of the temporary bonding adhesive precursor will be too low, also deviating from the normal processing viscosity requirements, failing to form a temporary bonding adhesive layer of the required thickness, and there may even be a risk of adhesive overflow, failing to meet normal processing requirements.

[0034] In some specific embodiments, the reactive diluent is selected from at least one of 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, and hydrogenated bisphenol A diglycidyl ether. The reactive diluent is a multifunctional (multiple epoxy groups) epoxy compound that adjusts the viscosity of the system and participates in the final cross-linking network to achieve solvent-free curing. The functionality (number of epoxy groups) of the reactive diluent is 2-3, which ensures the density of the cross-linking network and provides sufficient chemical stability and mechanical strength.

[0035] In some specific embodiments, the curing agent is an addition-type curing agent or a catalytic curing agent. The molar ratio of the active groups (such as anhydride groups, amino groups) in the addition-type curing agent to the total molar ratio of epoxy groups in the matrix resin and the reactive diluent is (0.85~1.05):1; specifically, the molar ratio can be 0.85:1, 0.88:1, 0.92:1, 0.95:1, 0.99:1, or 1.05:1, etc. The amount of the catalytic curing agent added is 1%~3% of the mass of the matrix resin; specifically, the mass percentage of the catalytic curing agent in the matrix resin can be 1%, 1.2%, 1.6%, 1.9%, 2.1%, 2.4%, 2.7%, or 3%, etc.

[0036] Hyperbranched polyacrylates dissolve in reactive diluents and react under the action of curing agents. Both the hyperbranched polyacrylates and the reactive diluents contain multiple epoxy groups. Ring-opening crosslinking curing of epoxy groups: By adding an external curing agent (addition type or catalytic type), the epoxy rings are opened, forming crosslinking points, and ultimately a three-dimensional polymer is constructed.

[0037] Depending on the type of curing agent and the reaction pathway, ring-opening crosslinking mechanisms mainly fall into two categories: addition polymerization and self-ring-opening polymerization. It can be the self-ring-opening polymerization of epoxy groups under catalytic curing agents; or it can be the addition polymerization reaction of epoxy groups with addition curing agents. Adjustments can be made according to actual process requirements, using appropriate molar ratios. Addition curing agents can ensure sufficient crosslinking points and fully crosslinked networks; the dosage of catalytic curing agents is mainly determined by considering the degree of reaction.

[0038] The curing agent is preferably an anhydride, amine, or imidazole. Specifically, the curing agent is selected from methylhexahydrophthalic anhydride (MHHPA), hexahydrophthalic anhydride (HHPA), methylnadic anhydride (MNA), dicyandiamide, diaminodiphenyl sulfone (DDS), 2-ethyl-4-methylimidazolium, etc. After the epoxy resin reacts with the curing agent, a highly cross-linked three-dimensional network structure is formed. When a catalytic curing agent (such as imidazole) is used, the epoxy groups undergo homopolymerization to generate high-bond-energy ether bonds, which helps to improve the heat resistance of the material. The hydroxyl groups generated in the curing reaction of anhydrides or amines can effectively improve the adhesion, wettability, and interfacial bonding strength of the material to the substrate. Ultimately, the dense cross-linked network endows the cured material with excellent heat resistance, stable mechanical properties, and chemical resistance.

[0039] In some specific embodiments, the hyperbranched temporary bonding adhesive further includes polyetherimide, which is 5wt% to 10wt% of the mass of the epoxy-containing hyperbranched polyacrylate; specifically, the polyetherimide can be 5%, 5.5%, 6.1%, 6.9%, 7.3%, 7.8%, 8%, 8.5%, 9.2%, or 10% of the mass of the epoxy-containing hyperbranched polyacrylate, etc. Thus, by adopting a thermoplastic-thermosetting composite matrix design and introducing polyetherimide (PEI) into the hyperbranched polyacrylate, the heat resistance of the temporary bonding adhesive layer can be improved, while enhancing the interfacial adhesion with the release layer and the silicon wafer substrate, ensuring greater bonding stability during high-temperature processing.

[0040] In some specific embodiments, the hyperbranched polyacrylate is obtained by polymerization of epoxy-containing acrylate monomers and regulating monomers using a multifunctional RAFT chain transfer agent. Hyperbranched polyacrylate can be prepared using RAFT (Reversible Addition-Fragmentation Chain Transfer) free radical polymerization; the hyperbranched polyacrylate can be prepared by the participation of a RAFT chain transfer agent in the reaction, and the prepared hyperbranched polyacrylate is used as the matrix resin. This application uses hyperbranched polyacrylate resin, which, compared to conventional epoxy resins and phenolic resins, has lower residual thermal stress, avoiding the risk of warpage; compared to silicone resins, it has superior mechanical properties and lower cost.

[0041] In some specific embodiments, the epoxy-containing acrylate monomer is selected from glycidyl methacrylate (GMA) or glycidyl acrylate, and / or the regulating monomer is selected from at least one of methyl acrylate, methyl methacrylate (MMA), butyl acrylate (BA), butyl methacrylate, isobornyl acrylate, isobornyl methacrylate (IBOMA), hydroxyethyl acrylate, hydroxyethyl methacrylate, and lauryl acrylate (LA); and / or the multifunctional RAFT chain transfer agent contains multiple thiol groups in its structure. Preferably, the number of thiol groups in the RAFT chain transfer agent is 3 to 4.

[0042] Epoxy-containing acrylate monomers are used to introduce crosslinkable epoxy functional groups into the polymer side chains; modulating monomers are used to adjust the polymer's glass transition temperature (Tg), flexibility, and solubility.

[0043] RAFT chain transfer agents serve as the core framework for synthesizing hyperbranched polymer structures. Multifunctional RAFT chain transfer agents with a functionality (i.e., the number of thiol groups) of 3–4 are selected as the core, initiating and controlling polymerization through their multiple active sites to directly prepare polyacrylate precursors with highly branched topologies. This precursor, due to its hyperbranched structure, possesses a high epoxy functional group density (high average functionality), which lays the structural foundation for the subsequent reaction with the curing agent to form a highly crosslinked three-dimensional network, thus ensuring the required chemical stability and mechanical strength of the cured adhesive layer.

[0044] In some specific embodiments, the epoxy-containing acrylate monomer accounts for 60% to 85% of the total monomer mass; specifically, the epoxy-containing acrylate monomer can account for 60%, 64%, 69%, 72%, 76%, 80%, or 85% of the total monomer mass, etc. This ensures that a sufficient amount of crosslinkable epoxy groups are introduced into the polymer side chains.

[0045] In some specific embodiments, the multifunctional RAFT chain transfer agent is selected from at least one of pentaerythritol tetra(3-mercaptopropionate) (PETMP) and trimethylolpropane tri(3-mercaptopropionate) (TTMP). This allows the RAFT chain transfer agent to have a functionality (number of thiol groups) of 3 to 4, ensuring the density of the crosslinked network and providing sufficient chemical stability and mechanical strength.

[0046] In some specific embodiments, the glass transition temperature (Tg) of the hyperbranched polyacrylate obtained by selecting appropriate monomers and their amounts is 30°C to 50°C; specifically, the glass transition temperature (Tg) of the hyperbranched polyacrylate can be 30°C, 32°C, 35°C, 37°C, 39°C, 42°C, 45°C, 47°C, or 50°C, etc.

[0047] The glass transition temperature (Tg) of the hyperbranched polyacrylate polymer before crosslinking and curing is set within this temperature range based on a comprehensive balance of material storage, dissolution, and processing characteristics. When the Tg is above room temperature, it exists in a stable glassy state under normal conditions as a solid powder, ensuring physical stability during long-term storage and transportation and preventing adhesion and clumping. When moderately heated (e.g., 40°C~50°C) during the preparation of the temporary bonding adhesive, the resin chain movement is activated, rapidly transforming into a highly elastic state. This allows for efficient and complete dissolution in the reactive diluent, forming a uniform and stable adhesive solution. This also imparts excellent leveling properties to the adhesive solution during spin coating, laying the foundation for obtaining a uniform thickness and defect-free cured film. Furthermore, the Tg value of the cured temporary bonding adhesive is 170°C~260°C, ensuring it can withstand high-temperature processing procedures.

[0048] In some specific embodiments, the present invention provides a method for preparing a thermosetting hyperbranched temporary bonding adhesive, which is obtained through the following steps.

[0049] 1) Synthesis of a matrix resin containing multiple epoxy groups in hyperbranched polyacrylate (HBP-GMA): The reversible addition-fragmentation chain transfer (RAFT) free radical polymerization method was adopted. Under nitrogen protection, a multifunctional RAFT chain transfer agent, an epoxy-containing acrylate monomer, a regulating monomer and a free radical initiator were dissolved in an organic solvent and reacted at 60~80℃ for 6~12h to obtain a hyperbranched polymer solution. After precipitation, washing and drying, the matrix resin was obtained.

[0050] The acrylate monomers containing epoxy groups account for 60% to 85% of the total monomer mass, the multifunctional RAFT chain transfer agent is added at 1% to 3% of the total monomer mass, the adjusting monomer is added at 15% to 40% of the total monomer mass, the free radical initiator is azobisisobutyronitrile (AIBN), and its addition amount is 0.25% to 1% of the total monomer mass; the organic solvent can be selected from 1,4-dioxane, tetrahydrofuran, N,N-dimethylformamide, N-methylpyrrolidone, etc., and its addition amount is 1.5 to 3 times the total monomer mass.

[0051] 2) Preparation of thermosetting hyperbranched temporary bonding adhesive: Mix the matrix resin obtained in step 1) with the reactive diluent and curing agent in proportion, and mechanically stir at room temperature or under moderate heating (<50℃) for 2~7h until completely homogeneous. Then, perform vacuum degassing at -0.090~-0.095MPa for 20~30min to obtain a uniform, transparent, bubble-free thermosetting hyperbranched temporary bonding adhesive, which should be stored in a light-proof and sealed container.

[0052] The mass ratio of reactive diluent to matrix resin is (0.3~0.5):1; the ratio r of the number of moles of active groups in addition-type curing agent to the total number of moles of epoxy groups in matrix resin and reactive diluent is (0.85~1.05):1; the catalytic curing agent is 1%~3% of the mass of matrix resin.

[0053] A curing accelerator may be added as needed. The curing accelerator is used to reduce the activation energy of the curing reaction and promote curing at medium and low temperatures. The amount added is 0.5% to 3% of the mass of the matrix resin. It can be selected from tertiary amines (such as DMP-30), quaternary ammonium salts or imidazole compounds (such as 2-ethyl-4-methylimidazole).

[0054] In a second aspect, the present invention provides the application of the thermosetting hyperbranched temporary bonding adhesive as described in the first aspect, wherein the thermosetting hyperbranched temporary bonding adhesive is used in wafer processing to temporarily bond the wafer to a carrier.

[0055] Temporary Bonding: Thermosetting hyperbranched temporary bonding adhesive is applied to a clean substrate (functional wafer or temporary carrier) surface via spin coating. The adhesive viscosity is controlled at 3000~10000 cP, the spin coating speed at 2000~6000 Rpm (adjusted according to wafer size), and the spin coating time at 30~90 s. The coated substrate is then placed on a temperature-controlled hot plate for a two-step heat treatment curing process: first, pre-curing at 80~100℃ for 30~40 min to allow the adhesive to level and initially gel; then, the temporary bonding step is performed, curing at a bonding processing temperature of 140~200℃ for 5~90 ​​min, resulting in a smooth, transparent adhesive layer with a film thickness of 50~100 μm. Another glass carrier coated with a release layer material is then bonded to the cured adhesive layer in a temporary bonding machine at 180~210℃ and 4~8 kN pressure for 4~8 min to form a complete bond pair.

[0056] During the temporary bonding process, the epoxy groups undergo a ring-opening polymerization reaction with the curing agent to form a dense three-dimensional cross-linked network. This process involves no small molecule volatilization, thus completing the temporary bonding between the wafer and the carrier.

[0057] Debonding: After the wafer fabrication process is completed, the bonded pairs are placed in a high-temperature pyrolysis furnace. Under the protection of inert gas (nitrogen, argon), the temperature is increased to the set debonding temperature window (320~360℃) at a rate of 10~20℃ / min, and held for 5~20min. This causes the cross-linked network of the temporary bonding adhesive layer material to undergo rapid thermal decomposition, achieving non-destructive separation of the carrier and the device wafer, and the debonding is completed.

[0058] The specific embodiments of the present invention will be further explained and described below through examples and comparative examples.

[0059] Unless otherwise specified, all reagents, materials, and instruments used in the following description are conventional reagents, materials, and instruments, all of which are commercially available. The reagents involved can also be synthesized using conventional synthetic methods. Unless otherwise specified, the methods in the examples are conventional methods in the art. Monomers conforming to this invention are commercially available.

[0060] Example 1 In this embodiment, the hyperbranched polyacrylate is hyperbranched polyglycidyl methacrylate as the matrix resin; and an anhydride curing agent is used for thermosetting to prepare a thermosetting hyperbranched temporary bonding adhesive.

[0061] 1) Preparation of thermosetting hyperbranched temporary bonding adhesive First, a matrix resin containing hyperbranched polyglycidyl methacrylate (HBP-GMA-1) is synthesized. The monomers used are: glycidyl methacrylate (GMA) as the main functional monomer, providing epoxy side groups; methyl methacrylate (MMA) and butyl acrylate (BA) as regulating monomers, used to balance rigidity and toughness.

[0062] In a three-necked flask equipped with a stirrer, condenser, and nitrogen inlet, 0.625 g of the RAFT chain transfer agent pentaerythritol tetra(3-mercaptopropionate) (PETMP) and 40 g of 1,4-dioxane dehydrated by molecular sieve treatment were added. Under nitrogen protection, 20.0 g of glycidyl methacrylate (GMA), 4.0 g of methyl methacrylate (MMA), 1.0 g of butyl acrylate (BA), and 0.125 g of azobisisobutyronitrile (AIBN) were added sequentially. The mixture was stirred in an oil bath at 70 °C for 10 h. After the reaction was completed, a hyperbranched polymer solution was obtained, which was precipitated by adding dropwise to 500 mL of hexane under mechanical stirring. The white precipitate was collected by filtration, washed three times with hexane, and dried in a vacuum oven at 50 °C for 24 h to obtain a white solid, which is the matrix resin containing hyperbranched polyglycidyl methacrylate (HBP-GMA-1). According to GPC testing, its weight-average molecular weight (Mw) is 18513 g / mol, and its PDI is 1.4. Titration using the hydrochloric acid-acetone method yields an epoxy value of 0.48 eq / 100g. The Tg value of hyperbranched polyglycidyl methacrylate is 42℃; the degree of branching is 0.55.

[0063] To prepare a thermosetting hyperbranched temporary bonding adhesive, the following raw materials were used: 100g of HBP-GMA-1 matrix resin, 35g of reactive diluent 1,4-butanediol diglycidyl ether (BDDGE); based on the molar number of active groups in the curing agent, the total molar number of matrix resin + reactive diluent epoxy, and the molar ratio of the two, r=0.95:1, 132g of curing agent methyl hexahydrophthalic anhydride (MHHPA) and 1.5g of curing accelerator 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) were added.

[0064] The prepared matrix resin powder was mixed with 1,4-butanediol diglycidyl ether (BDDGE) and mechanically stirred in a 40°C water bath for 3 hours until the resin was completely dissolved, resulting in a homogeneous viscous solution. Then, methyl hexahydrophthalic anhydride (MHHPA) and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) were added, and the mixture was stirred in the dark at room temperature for 2 hours to ensure thorough mixing and obtain a glue solution. Subsequently, the glue solution was transferred to a vacuum degassing machine and degassed under vacuum at -0.095 MPa for 30 minutes to obtain a colorless, transparent, bubble-free, and flowable glue solution, namely a thermosetting hyperbranched temporary bonding adhesive.

[0065] 2) Application of thermosetting hyperbranched temporary bonding adhesives Temporary bonding: A spin-coating process is used to coat the adhesive onto the functional wafer (carrier), controlling the adhesive viscosity at 6000 cP, the spin-coating speed at 2000 rpm, and the spin-coating time at 30 s. The coated carrier is then placed on a temperature-controlled hot plate for a two-step heat treatment curing: first, pre-curing at 100°C for 30 min to allow the adhesive to level and initially gel; then, the temporary bonding step is performed, curing at a bonding processing temperature of 140°C for 90 min, resulting in a smooth, transparent adhesive layer with an average film thickness of approximately 75 μm. Another glass substrate coated with a release layer material is then bonded to the cured adhesive layer in a temporary bonding machine at 200°C and 5 kN pressure for 5 min, forming a complete bond pair and completing the temporary bonding between the wafer and the carrier.

[0066] Debonding: After the wafer fabrication process is completed, the bonded pairs are placed in a tube furnace and heated to 340°C at a rate of 10°C / min under a nitrogen atmosphere, and held at that temperature for 15 minutes. After natural cooling, the carrier and the device wafer are cleanly separated, and debonding is complete. There is no visible adhesive layer material residue on the wafer, and subsequent cleaning of the wafer is completed using a cleaning solvent.

[0067] Example 2 In this embodiment, the hyperbranched polyacrylate is hyperbranched glycidyl methacrylate, used as the matrix resin. The hyperbranched glycidyl methacrylate and thermosetting hyperbranched temporary bonding adhesive were synthesized using the procedures outlined in Example 1. The main differences from Example 1 are: the monomers used in the synthesis of the hyperbranched glycidyl methacrylate and their amounts are different; the amounts, molar ratios, curing agents, and curing accelerators used in the preparation of the thermosetting hyperbranched temporary bonding adhesive are also different.

[0068] Specifically, in the synthesis of hyperbranched polyglycidyl methacrylate, the monomers used were: 21.5 g of glycidyl methacrylate (GMA) and adjusting monomers of 3.0 g of isobornyl methacrylate (IBOMA) and 1.0 g of butyl acrylate (BA); the rest were the same as in Example 1. The reaction yielded hyperbranched polyglycidyl methacrylate, which, upon testing, had a weight-average molecular weight (Mw) of 16236 g / mol, a PDI of 1.5, and an epoxy value of 0.52 eq / 100 g. The Tg value of the hyperbranched polyglycidyl methacrylate was 48 °C; the degree of branching was 0.52.

[0069] In the preparation of thermosetting hyperbranched temporary bonding adhesive, the raw materials are: 100g of matrix resin, 30g of reactive diluent neopentyl glycol diglycidyl ether; based on the molar number of active groups in the curing agent, the total molar number of epoxy in the matrix resin + reactive diluent and the molar ratio of the two, r=1.01:1, 158g of curing agent methyl nadic anhydride (MNA) and 1g of curing accelerator 2-ethyl-4-methylimidazole are added.

[0070] The application of the thermosetting hyperbranched temporary bonding adhesive is basically the same as the operation steps in Example 1, except that the average film thickness after curing in the temporary bonding process is about 80 μm; during debonding, the temperature is increased to 360°C at 10°C / min and held for 20 min. No adhesive residue is left after cleaning.

[0071] Example 3 In this embodiment, the hyperbranched polyacrylate is hyperbranched glycidyl methacrylate, used as the matrix resin. The hyperbranched glycidyl methacrylate and thermosetting hyperbranched temporary bonding adhesive were synthesized using the procedures outlined in Example 1. The main differences from Example 1 are in the adjustment of monomers and their amounts during the synthesis of the hyperbranched glycidyl methacrylate; and in the preparation of the thermosetting hyperbranched temporary bonding adhesive, the amounts and molar ratios of the reactive diluent, curing agent, and curing accelerator, as well as their amounts.

[0072] Specifically, in the synthesis of hyperbranched polyglycidyl methacrylate, the monomers used were: 18.0 g of glycidyl methacrylate (GMA) and adjusting monomers of 2.0 g of methyl methacrylate (MMA) and 5.0 g of lauryl acrylate (LA); the RAFT chain transfer agent was 0.75 g of trimethylolpropane tris(3-mercaptopropionic acid) ester (TTMP), and the initiator was 0.25 g of azobisisobutyronitrile (AIBN); the rest were the same as in Example 1. The reaction yielded hyperbranched polyglycidyl methacrylate, which, upon testing, had a weight-average molecular weight (Mw) of 20752 g / mol, a PDI of 1.6, and an epoxy value of 0.41 eq / 100 g. The Tg value of the hyperbranched polyglycidyl methacrylate was 35 °C; the degree of branching was 0.50.

[0073] In the preparation of thermosetting hyperbranched temporary bonding adhesive, the raw materials are: 100g of matrix resin, 40g of reactive diluent 1,4-butanediol diglycidyl ether (BDDGE); based on the molar number of active groups in the curing agent, the total molar number of epoxy in the matrix resin + reactive diluent and the molar ratio of the two, r=0.90:1, 122g of methylhexahydrophthalic anhydride (MHHPA) and 0.8g of curing accelerator 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) are added.

[0074] The application of the thermosetting hyperbranched temporary bonding adhesive is basically the same as the operation steps in Example 1, except that the average film thickness after curing in the temporary bonding is approximately 90 μm. No adhesive residue is left after cleaning.

[0075] Example 4 In this embodiment, the hyperbranched polyacrylate is hyperbranched glycidyl methacrylate, which is used as the matrix resin. The hyperbranched glycidyl methacrylate and thermosetting hyperbranched temporary bonding adhesive are synthesized using the steps of Example 1. The main difference from Example 1 is that 10g of polyetherimide (PEI) (Mw=30000g / mol) is also added to the preparation of the thermosetting hyperbranched temporary bonding adhesive.

[0076] The prepared matrix resin and PEI powder were mixed with BDDGE and mechanically stirred in a 40°C water bath for 3 hours until the resin was completely dissolved, resulting in a homogeneous viscous solution. Then, MHHPA and DMP-30 were added, and the mixture was stirred at room temperature in the dark for another 4 hours to ensure thorough mixing and obtain a glue solution. Subsequently, the glue solution was transferred to a vacuum degassing machine and degassed under vacuum at -0.095MPa for 30 minutes to obtain a pale yellow, transparent, and flowable glue solution, which is a thermosetting hyperbranched temporary bonding adhesive.

[0077] The application of the thermosetting hyperbranched temporary bonding adhesive is basically the same as the operation steps in Example 1, except that the average film thickness after curing in the temporary bonding process is approximately 78 μm. No adhesive residue was left after cleaning.

[0078] Example 5 In this embodiment, the hyperbranched polyacrylate is hyperbranched glycidyl methacrylate, used as the matrix resin. The hyperbranched glycidyl methacrylate was synthesized and a thermosetting hyperbranched temporary bonding adhesive was prepared using the procedures outlined in Example 1. The main differences from Example 1 are in the functional monomers, regulating monomers, and their amounts used in the synthesis of the hyperbranched glycidyl methacrylate; and in the amounts, molar ratios, curing agents, and curing accelerators used in the preparation of the thermosetting hyperbranched temporary bonding adhesive.

[0079] Specifically, in the synthesis of hyperbranched polyglycidyl methacrylate, the monomers used were: 20.0 g of glycidyl acrylate and 4.0 g of hydroxyethyl methacrylate and 1.0 g of lauryl acrylate (LA) as adjusting monomers; the rest were the same as in Example 1. The reaction conditions were the same as in Example 1, yielding hyperbranched polyglycidyl methacrylate. The weight-average molecular weight (Mw) was 21854 g / mol, and the PDI was 1.4. The epoxy value was 0.56 eq / 100g. The Tg value of the hyperbranched polyglycidyl methacrylate was 38℃; the degree of branching was 0.58.

[0080] In the preparation of thermosetting hyperbranched temporary bonding adhesive, the raw materials are: 100g matrix resin, 50g reactive diluent 1,4-butanediol diglycidyl ether (BDDGE); based on the molar number of active groups in the curing agent, the total molar number of epoxy in the matrix resin + reactive diluent, and the molar ratio of the two, r=0.95:1, add 167g curing agent methyl hexahydrophthalic anhydride (MHHPA); 1.5g curing accelerator DMP-30; and 8g polyetherimide (PEI).

[0081] The prepared matrix resin and PEI powder were mixed with BDDGE and mechanically stirred in a 40°C water bath for 3 hours until the resin was completely dissolved, resulting in a homogeneous viscous solution. Then, MHHPA and DMP-30 were added, and the mixture was stirred at room temperature in the dark for another 4 hours to ensure thorough mixing and obtain a glue solution. Subsequently, the glue solution was transferred to a vacuum degassing machine and degassed under vacuum at -0.095MPa for 30 minutes to obtain a pale yellow, transparent, and flowable glue solution, which is a thermosetting hyperbranched temporary bonding adhesive.

[0082] The application of the thermosetting hyperbranched temporary bonding adhesive is basically the same as the operation steps in Example 1, except that the average film thickness after curing in the temporary bonding is approximately 85 μm. No adhesive residue was left after cleaning.

[0083] Example 6 In this embodiment, the hyperbranched polyacrylate is hyperbranched polyglycidyl methacrylate, used as the matrix resin. The hyperbranched polyglycidyl methacrylate and thermosetting hyperbranched temporary bonding adhesive were synthesized using the procedures outlined in Example 1. The main difference from Example 1 lies in the curing agent and its dosage in the preparation of the thermosetting hyperbranched temporary bonding adhesive.

[0084] Specifically, 100g of the prepared matrix resin powder is mixed with 35g of BDDGE and mechanically stirred in a 40℃ water bath for 3 hours until the resin is completely dissolved, resulting in a homogeneous viscous solution. Then, 3g of curing agent 2-ethyl-4-methylimidazole is added, and the mixture is stirred at room temperature in the dark for 2 hours to ensure thorough mixing and obtain a glue solution. Subsequently, the glue solution is transferred to a vacuum degassing machine and degassed under vacuum at -0.095MPa for 30 minutes to obtain a colorless, transparent, and flowable glue solution, namely a thermosetting hyperbranched temporary bonding adhesive.

[0085] The application of the thermosetting hyperbranched temporary bonding adhesive is basically the same as the operation steps in Example 1, except that the average film thickness after curing in the temporary bonding is approximately 70 μm. No adhesive residue was left after cleaning.

[0086] Example 7 In this embodiment, the hyperbranched polyacrylate is hyperbranched glycidyl methacrylate, which is used as the matrix resin. The hyperbranched glycidyl methacrylate and thermosetting hyperbranched temporary bonding adhesive are synthesized using the steps of Example 1. The main difference from Example 1 is that the amount of monomer used in the synthesis of hyperbranched glycidyl methacrylate is not within the scope disclosed in this application.

[0087] Specifically, in a three-necked flask equipped with a stirrer, condenser, and nitrogen inlet, 0.625 g of the RAFT chain transfer agent pentaerythritol tetra(3-mercaptopropionate) (PETMP) and 40 g of 1,4-dioxane dehydrated by molecular sieve treatment were added. Under nitrogen protection, 22.5 g of GMA, 1.5 g of methyl methacrylate (MMA), 1.0 g of butyl acrylate (BA), and 0.0675 g of azobisisobutyronitrile (AIBN) were added. The reaction conditions were the same as in Example 1, yielding a matrix resin containing hyperbranched polyglycidyl methacrylate. The weight-average molecular weight (Mw) was 24373 g / mol, and the PDI was 1.4. The epoxy value was 0.62 eq / 100 g; the Tg value of the hyperbranched polyglycidyl methacrylate was 46 °C; and the degree of branching was 0.65.

[0088] The application of the thermosetting hyperbranched temporary bonding adhesive follows the same procedure as in Example 1, except that the average film thickness after curing in the temporary bonding process is approximately 72 μm. No adhesive residue was left after cleaning.

[0089] Example 8 In this embodiment, the hyperbranched polyacrylate is hyperbranched glycidyl methacrylate, which is used as the matrix resin. The hyperbranched glycidyl methacrylate and thermosetting hyperbranched temporary bonding adhesive are synthesized using the steps of Example 1. The main difference from Example 1 is that the amount of monomer used in the synthesis of hyperbranched glycidyl methacrylate is not within the scope disclosed in this application.

[0090] Specifically, in the synthesis of hyperbranched polyglycidyl methacrylate, the monomers used were: 13.75 g of glycidyl methacrylate (GMA), and adjusting monomers of 9 g of methyl methacrylate (MMA) and 2.25 g of butyl acrylate (BA); the rest were the same as in Example 1. The reaction yielded hyperbranched polyglycidyl methacrylate, which, upon testing, had a weight-average molecular weight (Mw) of 19182 g / mol, a PDI of 1.4, an epoxy value of 0.47 eq / 100g, a Tg value of 40℃, and a branching degree of 0.51.

[0091] The application of the thermosetting hyperbranched temporary bonding adhesive is basically the same as the procedure in Example 1, except that the average film thickness after curing in the temporary bonding process is approximately 77 μm. No adhesive residue was left after cleaning.

[0092] Comparative Example 1 This comparative example temporary bonding adhesive uses a solvent-based linear epoxy resin system commonly used in advanced encapsulation fields to simulate and compare the performance limitations of existing technologies.

[0093] The raw materials for the temporary bonding adhesive are as follows: bisphenol A type epoxy resin (E-51, epoxy value 0.48-0.54 eq / 100g) is used as the base resin, based on 100 parts; linear phenolic resin as the curing agent, brand PF-8210, with a hydroxyl equivalent of approximately 105 g / eq, is used in an amount of 85 parts, calculated based on the equivalent ratio of E / H to epoxy resin = 1:0.85; 0.5 parts of 2-methylimidazole as a curing accelerator; and sufficient organic solvent (a mixed solution of cyclohexanone and propylene glycol methyl ether acetate, mass ratio 1:1) to dissolve the above solid components and adjust them to the target solid content and viscosity to match the requirements of the processing technology.

[0094] Preparation steps of the temporary bonding adhesive: Bisphenol A type epoxy resin and linear phenolic resin powder were added to a mixed organic solvent and mechanically stirred in a 50°C water bath for 4 hours until completely dissolved, obtaining a homogeneous solution. Then, 2-methylimidazole was added and stirred at room temperature for 30 minutes to ensure uniform dispersion. Finally, the adhesive solution was transferred to a vacuum degassing machine and degassed under a vacuum of -0.095 MPa for 30 minutes, yielding a pale yellow transparent adhesive solution with a solid content of 65 wt%, i.e., the temporary bonding adhesive. This system is a typical physical mixture of a linear polymer dissolved in an inert solvent.

[0095] Temporary bonding: Using the same spin coating process as in Example 1, the adhesive was coated onto the functional wafer at spin coating parameters of 2000 rpm / 30 s. A two-step heat treatment was then performed to simulate existing processes: first, the wafer was treated on a hot plate at 120°C for 30 min. The main purpose of this stage was to evaporate and remove most of the organic solvents, forming a pre-dried adhesive film; then, the temperature was raised to 180°C and held for 120 min to complete the thermal crosslinking and curing reaction between the epoxy resin and the phenolic resin. The average thickness of the cured film was approximately 80 μm. The bonding process was the same as in Example 1, with bonding at 200°C and 5 kN pressure for 5 min to form complete bond pairs, completing the temporary bonding between the wafer and the carrier.

[0096] Debonding: Under nitrogen protection, the temperature was increased at 10℃ / min. It was observed that the material began to slowly decompose at around 280℃ and produced a large amount of smoke. It was not completely decomposed at 380℃. After the carrier separated from the wafer, residual adhesive remained at the interface, and clean debonding could not be achieved.

[0097] Comparative Example 2 This comparative example temporary bonding adhesive uses a thermoplastic polymer system to simulate existing technologies that rely on solvent evaporation for film formation and physical entanglement, in order to compare their limitations in high-performance packaging scenarios.

[0098] The raw materials for the temporary bonding adhesive are: 100 parts of polyamide resin (brand name PA6 / 66); 30 parts of tackifying resin hydrogenated petroleum resin (brand name ARKON P-140); 2 parts of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; and sufficient amount of highly polar organic solvent N-methylpyrrolidone (NMP) to dissolve the above solid components and adjust them to the target solid content and viscosity.

[0099] The preparation steps of the temporary bonding adhesive are as follows: Polyamide resin particles, hydrogenated petroleum resin, and antioxidant are added to NMP solvent and mechanically stirred in an oil bath at 70°C for 5-7 hours until all solids are completely dissolved, resulting in a homogeneous, viscous, pale yellow adhesive solution. The adhesive solution is then transferred to a vacuum degassing machine and degassed at -0.095 MPa for 60 minutes to obtain a thermoplastic polymer adhesive solution with a solids content of 50 wt%. This system relies entirely on physical dissolution and solvent evaporation to form a film, without any chemical crosslinking reaction.

[0100] Temporary bonding: Using the same spin coating process as in Example 1, the adhesive was applied to the functional wafer at spin coating parameters of 2000 rpm / 30 s. Subsequently, thermal curing was performed: the wafer was treated on a hot plate at 160°C for 90 min. The purpose of this stage was to completely remove the NMP solvent, allowing the polyamide molecular chains to form an adhesive layer through physical entanglement. The average film thickness after curing was approximately 75 μm. The bonding process was the same as in Example 1, with bonding performed at 200°C and 5 kN pressure for 5 min to form complete bond pairs, thus completing the temporary bonding between the wafer and the carrier.

[0101] Debonding: Using the hot-slip method, the bonded pairs are placed on a hot plate, heated to 210-220℃ and held for 5 minutes. After the adhesive layer softens, a slight shear force is applied to allow the carrier to slide and separate from the wafer. After debonding, a thin, translucent adhesive film residue can be observed on the wafer surface, which requires ultrasonic cleaning with an additional organic solvent (such as dimethyl sulfoxide) to completely remove.

[0102] Comparative Example 3 The reactive diluent in this comparative example temporary bonded adhesive is phenyl glycidyl ether, and the rest are the same as in Example 1. Phenyl glycidyl ether is a monofunctional reactive diluent. During the final film formation process, it grafts onto the molecular chains of the polymer matrix, but it cannot form a cross-linked network structure. This comparative example aims to demonstrate that the use of a multifunctional reactive diluent is a necessary condition for forming a high cross-linking density, high-performance temporary bonded adhesive polymer network.

[0103] The specific difference lies in the raw materials for the temporary bonding adhesive: 100g of HBP-GMA-1 matrix resin, 35g of monofunctional reactive diluent phenyl glycidyl ether; the curing agent, curing accelerator and their dosage are exactly the same as in Example 1, namely 132g of methyl hexahydrophthalic anhydride (MHHPA) and 1.5g of DMP-30.

[0104] Comparative Example 4 The polyacrylate used in this comparative example is polyglycidyl methacrylate (PGMA), which was used as the matrix resin. PGMA and a thermosetting temporary bonding adhesive were synthesized following the procedures outlined in Example 1. The main difference from Example 1 is that the RAFT reagent used in the synthesis of PGMA is a monofunctional polyfunctional 2-cyano-2-propylbenzodithioate (CPDB). Therefore, the polymer obtained from the reaction is not a hyperbranched structure but rather a linear polyfunctional polymer.

[0105] The application of thermosetting temporary bonding adhesive follows the same procedure as in Example 1.

[0106] Performance testing: To comprehensively evaluate the performance of the thermosetting hyperbranched temporary bonding adhesive described in this invention and to compare it with existing technologies, the temporary bonding adhesives of Examples 1-8 and Comparative Examples 1-4 were subjected to the following performance tests. The test methods were conducted according to national standards or industry-standard methods.

[0107] 1. Thermal performance testing [Glass Transition Temperature (Tg)]: The Tg value of the cured temporary bonded adhesive was determined using dynamic thermomechanical analysis (DMA). Test conditions: single cantilever beam mode, frequency 1Hz, heating rate 3℃ / min, test temperature range -50℃ to 300℃. The temperature corresponding to the peak value of the loss modulus (E'') was taken as the Tg value.

[0108] [Thermal Decomposition Temperature (Td 5%)]: Determined by thermogravimetric analysis (TGA) according to standard GB / T 27761-2011. Test conditions: nitrogen atmosphere, heating rate 10℃ / min, record the temperature at which 5% mass loss occurs.

[0109] 2. Mechanical performance testing [Room temperature shear strength]: According to standard GB / T 7124-2008, stainless steel-stainless steel lap shear specimens were prepared and tested at room temperature using a universal testing machine at a rate of 10 mm / min.

[0110] 【200℃ High Temperature Shear Strength】: The test method is the same as at room temperature. The sample and fixture are placed in a 200℃ high temperature environment and kept at that temperature for 10 minutes before the test.

[0111] 3. Chemical resistance test [Mass Change Rate]: Temporary bonding adhesive was first spin-coated onto a pure silicon wafer substrate without any devices. The cured adhesive film (100±1 μm thick) was then immersed in the following reagents and stored at room temperature for 24 hours: ① acetone; ② N-methylpyrrolidone (NMP); ③ 10 wt% hydrochloric acid solution; ④ 10 wt% potassium hydroxide solution. After removal, the appearance was observed, and the surface was blotted dry with filter paper before weighing. The mass change rate was then calculated.

[0112] 4. Evaluation of the film quality of the adhesive layer [Thickness and Uniformity]: Using a contact thin film thickness gauge, temporary bonding adhesive was spin-coated onto a bare silicon wafer to form a film. After curing, nine points were randomly selected to measure the film thickness, and the average value and standard deviation were calculated.

[0113] 5. Debonding performance evaluation [Debonding Temperature and Time]: Under nitrogen protection, the bonded pair was placed in a programmable temperature controlled furnace, and the temperature at which the carrier and the wafer were completely separated and the holding time at that temperature (i.e., debonding time) were recorded.

[0114] 6. Interface residue assessment: After debonding, the wafer surface is visually inspected and assessed using an optical microscope (200x) to evaluate the residual adhesive.

[0115] The test results are summarized and recorded in Tables 1 and 2.

[0116] Table 1 Table 2 The following results analysis is based on the test results in Tables 1 and 2.

[0117] 1) Regarding heat resistance and high-temperature support: The temporary bonding adhesive of this invention benefits from its hyperbranched structure and high crosslinking density, forming a more uniform and dense polymer three-dimensional network. This results in significantly higher thermal decomposition temperatures (all >300℃) and excellent high-temperature shear strength (>25 MPa at 200℃). If the mass of acrylate monomers containing epoxy groups accounts for a larger proportion of the total monomer mass (Example 7), the Tg of the cured temporary bonding adhesive will be relatively low, the thermal decomposition temperature will be slightly lower but still greater than 300℃, and the mechanical properties will be slightly lower but the shear strength at 200℃ will still be greater than 25 MPa. The temporary bonding adhesive of this invention has good thermal stability, providing continuous and stable high-temperature support in advanced packaging processes, and maintaining stable bond strength and structural integrity in high-temperature processes. Moreover, the addition of polyetherimide (PEI) to the thermosetting hyperbranched temporary bonding adhesive of this invention can improve the heat resistance of the bonding layer, while enhancing the interfacial adhesion with the release layer and silicon wafer substrate, ensuring bond stability during high-temperature processing.

[0118] However, Comparative Example 1, due to its solvent-based linear epoxy resin system, had a low Tg value and thermal decomposition temperature, and was severely softened at 200℃. Comparative Example 2, using a thermoplastic polymer system, had an even lower Tg value and thermal decomposition temperature, resulting in complete failure and inability to meet the requirements of high-temperature processes. Comparative Example 3, using a monofunctional reactive diluent, could not form a cross-linked network structure, leading to a low thermal decomposition temperature and insufficient high-temperature shear strength, thus failing to meet the requirements of high-temperature processes. Comparative Example 4, using a matrix resin polymer that was not hyperbranched but only a multifunctional linear polymer, resulted in insufficient high-temperature shear strength, failing to meet the requirements of high-temperature processes.

[0119] 2) Regarding chemical resistance: The temporary bonded adhesive of this invention exhibits a very small mass change rate (<2.0%) in various chemical reagents, and its dense cross-linked network effectively blocks solvent penetration. If the mass of acrylate monomers containing epoxy groups accounts for a smaller proportion of the total monomer mass (Example 8), the chemical resistance of the temporary bonded adhesive in solvents is slightly worse, but the mass change rate is still less than 2.0%. However, Comparative Example 1, due to microscopic defects left by solvent evaporation and a low cross-linking density, experiences severe swelling in organic solvents. Comparative Example 2 dissolves directly due to its thermoplastic nature. Comparative Example 3, using a monofunctional reactive diluent, swells in highly polar solvents (acetone, NMP) because it cannot form a cross-linked network structure. The temporary bonding adhesive of this invention exhibits excellent solvent resistance, especially against highly polar solvents (acetone, NMP). The core of this invention lies in the dual effect of the defect-free dense network formed by "solvent-free" curing and the low free volume of the hyperbranched structure itself. The reactive diluent directly participates in the ring-opening copolymerization reaction of the epoxy groups, becoming part of the crosslinking network. Combined with the hyperbranched polyacrylate, the high crosslinking density constructs an extremely high chemical corrosion barrier, preventing the formation of micropores due to solvent evaporation. The dense crosslinking network and the tight stacking of hyperbranched molecules make it extremely difficult for small solvent molecules to penetrate and swell the polymer chains.

[0120] 3) Regarding film quality and low stress: The present invention can spontaneously form a smoother film layer with a thickness deviation (<±1μm) much smaller than that of the comparative example. This is due to the low viscosity, high leveling properties and low shrinkage characteristics of the hyperbranched resin, which fundamentally reduces the internal stress that causes wafer warping.

[0121] 4) Regarding controllable and clean debonding: The temporary bonding adhesive of the present invention can quickly (10-15 min) complete thermal decomposition at a set temperature (320~360℃), and the decomposition products are easily volatile or small molecules, achieving non-destructive and residue-free debonding; if the mass of acrylate monomers containing epoxy groups accounts for more than the total mass of monomers (Example 7), due to more crosslinking sites, higher temperature and time are required to complete debonding; if the mass of acrylate monomers containing epoxy groups accounts for less than the total mass of monomers (Example 8), due to fewer crosslinking sites, the debonding temperature and time are lower than those in Example 1.

[0122] However, Comparative Example 1 exhibited high and incomplete thermal decomposition, resulting in a large amount of viscous and difficult-to-remove residue. While Comparative Example 2 achieved low-temperature debonding, it left physical residues, requiring additional cleaning steps and increasing process complexity and contamination risk. Comparative Example 3, although achieving good debonding performance under the same conditions, left visible thin adhesive dots on the wafer surface due to the use of a monofunctional reactive diluent, necessitating additional solvent cleaning. Comparative Example 4 also achieved good debonding performance under the same conditions, but because the polymer used as the matrix resin was not hyperbranched but rather a multifunctional linear polymer, a small amount of visible adhesive residue remained on the wafer surface, requiring additional solvent cleaning. This invention addresses the "disintegration" characteristic of hyperbranched structures during thermal decomposition, stemming from their numerous branching points and short branched chains. Upon heating, these branching points become initiation points for thermal decomposition, allowing the entire network to break down relatively uniformly and rapidly into small molecular fragments, which are then easily volatilized, achieving clean decomposition without residue.

[0123] In summary, the thermosetting hyperbranched temporary bonding adhesive provided by this invention is superior to traditional solvent-based linear thermosetting and thermoplastic systems in key performance aspects such as heat resistance, chemical resistance, film quality, and controllable clean debonding, and can perfectly meet the stringent requirements of 2.5D / 3D advanced encapsulation.

[0124] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A thermosetting hyperbranched temporary bonding adhesive, characterized in that, The temporary bonding adhesive includes a matrix resin, a reactive diluent, and a curing agent. The matrix resin includes a hyperbranched polyacrylate containing multiple epoxy groups. The reactive diluent contains multiple epoxy groups. The hyperbranched polyacrylate is dissolved in the reactive diluent and can undergo a crosslinking reaction under the action of the curing agent.

2. The thermosetting hyperbranched temporary bonding adhesive according to claim 1, characterized in that, The epoxy groups of the hyperbranched polyacrylate are located on the side groups of its molecular chain, and the epoxy value of the hyperbranched polyacrylate is 0.4~0.6 eq / 100g. And / or, the degree of branching of the hyperbranched polyacrylate is 0.5 to 0.7; And / or, the weight-average molecular weight of the hyperbranched polyacrylate is 15,000 to 25,000 g / mol; And / or, the PDI of the hyperbranched polyacrylate is 1.3 to 1.9; And / or, the glass transition temperature (Tg) of the hyperbranched polyacrylate is 30°C to 50°C.

3. The thermosetting hyperbranched temporary bonding adhesive according to claim 1, characterized in that, The mass ratio of the reactive diluent to the matrix resin is (0.3~0.5):1; And / or, the active diluent is selected from at least one of 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, and hydrogenated bisphenol A diglycidyl ether.

4. The thermosetting hyperbranched temporary bonding adhesive according to claim 1, characterized in that, The curing agent is an addition-type curing agent or a catalytic curing agent; And / or, the ratio of the molar number of active groups in the addition-curing agent to the total molar number of epoxy groups in the matrix resin and the reactive diluent is (0.85~1.05):1; And / or, the catalytic curing agent is 1% to 3% of the mass of the matrix resin.

5. The thermosetting hyperbranched temporary bonding adhesive according to claim 1, characterized in that, The hyperbranched temporary bonding adhesive also includes polyetherimide, which is 5 wt% to 10 wt% of the mass of the hyperbranched polyacrylate.

6. The thermosetting hyperbranched temporary bonding adhesive according to claim 1 or 2, characterized in that, The hyperbranched polyacrylate is obtained by polymerization of epoxy-containing acrylate monomers and regulating monomers using a multifunctional RAFT chain transfer agent.

7. The thermosetting hyperbranched temporary bonding adhesive according to claim 6, characterized in that, The epoxy-containing acrylate monomers are selected from glycidyl methacrylate or glycidyl acrylate. And / or, the regulating monomer is selected from at least one of methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, isobornyl acrylate, isobornyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, and lauryl acrylate. And / or, the structure of the multifunctional RAFT chain transfer agent contains multiple thiol groups.

8. The thermosetting hyperbranched temporary bonding adhesive according to claim 6, characterized in that, The acrylate monomers containing epoxy groups account for 60% to 85% of the total monomer mass.

9. The thermosetting hyperbranched temporary bonding adhesive according to claim 7, characterized in that, The multifunctional RAFT chain transfer agent is selected from at least one of pentaerythritol tetra(3-mercaptopropionate) and trimethylolpropane tri(3-mercaptopropionate).

10. The application of a thermosetting hyperbranched temporary bonding adhesive as described in any one of claims 1 to 9, characterized in that, The thermosetting hyperbranched temporary bonding adhesive is used in wafer fabrication to temporarily bond the wafer to a carrier.

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