Temporary bonding adhesive and temporary bonding method

Abstract

This invention discloses a temporary bonding adhesive and a temporary bonding method. The temporary bonding adhesive, by weight, comprises the following components: 3-7 parts of a base resin, 2-5 parts of a heat-resistant reactive resin, 0.5-2 parts of a stress-reducing resin, 0.01-0.5 parts of a reactive interface modifier, and 0.01-0.5 parts of a photoinitiator. The base resin is a high molecular weight acrylate resin. The heat-resistant reactive resin is used to form a partially cross-linked network with the base resin components under ultraviolet light. The reactive interface modifier is used to react or co-crosslink with other components under ultraviolet light. In specific embodiments, this temporary bonding adhesive, when applied to temporary bonding, can still maintain sufficient bonding strength even at temperatures above 220°C, thereby preventing wafer detachment. When cooled to room temperature, the bonding strength decreases, thus enabling controlled peeling.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a temporary bonding adhesive and a temporary bonding method. Background Technology

[0002] In semiconductor manufacturing, temporary bonding technology is typically used to temporarily fix wafers to a carrier substrate to support the high-precision processing requirements of wafers in processes such as thinning, rewiring, 3D integration, or fan-out packaging. As a key material in this technology, the temporary bonding adhesive needs to withstand heat treatment at certain temperatures during subsequent processing while maintaining the structural integrity of the adhesive layer and the stability of the interfacial bonding. With the development of advanced packaging technologies, the processing temperatures involved in some semiconductor processing steps are gradually increasing. Under high-temperature conditions, the temporary bonding adhesive needs to maintain sufficient bonding stability to prevent wafer detachment or displacement during processing, and also needs to be easily peeled off after processing to minimize damage to the wafer or carrier substrate.

[0003] However, existing temporary bonding adhesive systems often struggle to simultaneously achieve both high-temperature stability and subsequent peelability. When the adhesive layer is designed with high curing or high cross-linking to improve heat resistance, problems such as peeling difficulties, increased adhesive residue, or uncontrollable interface damage can easily occur during the peeling stage. On the other hand, when the degree of cross-linking of the adhesive layer is low, softening, flow, or bonding failure may occur during high-temperature processing.

[0004] Therefore, it remains necessary to provide a temporary bonding adhesive and its application method that can remain stable during high-temperature semiconductor processing and achieve controllable peeling after processing. Summary of the Invention

[0005] This invention provides a high-temperature resistant temporary bonding adhesive for semiconductor processes and a temporary bonding method thereof. The temporary bonding adhesive employs a multi-component synergistic design, and through ultraviolet light pretreatment, the adhesive layer forms a controlled partially cross-linked network structure, thereby maintaining sufficient bonding stability during subsequent high-temperature semiconductor processing and achieving controllable peeling after processing is completed and cooled to room temperature.

[0006] Unlike existing temporary bonding adhesive systems that rely on a single heat-resistant precursor for high curing, this invention controls the degree of crosslinking of the adhesive layer during the UV pretreatment stage, causing the adhesive layer to exhibit different mechanical and interfacial behaviors during the high-temperature processing stage and the cooling and peeling stage. This ensures high-temperature stability while avoiding peeling difficulties or residue problems caused by excessive crosslinking.

[0007] Specifically, the temporary bonding adhesive of the present invention forms a partially cross-linked network structure with a gel fraction of 50% to 90% after ultraviolet light irradiation. This partially cross-linked network structure can inhibit the softening, flow, or creep of the adhesive layer under high temperature conditions of 220°C to 320°C, maintaining the bonding stability between the carrier substrate and the wafer; while after the high-temperature processing is completed and cooled to room temperature, the interfacial bonding force of the adhesive layer decreases, thereby enabling overall or substantially overall peeling by mechanical means.

[0008] A temporary bonding adhesive, comprising, by weight parts, the following components: 30 to 70 parts of a base resin, 20 to 50 parts of a heat-resistant reactive resin, 5 to 20 parts of a stress-reducing resin, 0.1 to 3 parts of a reactive interface modifier, and 0.1 to 3 parts of a photoinitiator; The host resin is a high molecular weight polymer with film-forming and initial adhesion properties, serving as the continuous phase of the adhesive layer to provide good film-forming properties, matrix continuity, and processing adaptability for the temporary bonded adhesive. Before UV pretreatment, the host resin mainly provides the initial adhesion properties and morphological stability of the adhesive layer; during UV pretreatment and subsequent high-temperature processing, the host resin, along with other components, participates in forming a partially cross-linked network structure, but does not act as the sole heat-resistant component in the system.

[0009] The heat-resistant reactive resin is a resin component with a heat-resistant structure and functional groups that can participate in cross-linking reactions. During the UV pretreatment stage, this heat-resistant reactive resin, together with the host resin, participates in forming a partially cross-linked network structure. In subsequent high-temperature semiconductor processing, it is used to improve the modulus and structural stability of the adhesive layer under high-temperature conditions, thereby inhibiting softening, flow, or creep of the adhesive layer. The heat-resistant reactive resin does not form a highly cross-linked three-dimensional network structure alone, but rather, as part of a multi-component system, it works synergistically with the host resin and other components to achieve a balance between high-temperature stability and peelability.

[0010] The stress-buffering resin is a polymer material containing flexible segments, used to introduce a stress-buffering phase into the adhesive layer to alleviate the internal or interfacial stress generated during ultraviolet light pretreatment, high-temperature semiconductor processing, and subsequent peeling, thereby reducing the risk of the adhesive layer becoming brittle, failing at the interface, or being uncontrollably damaged during high-temperature processing or mechanical peeling.

[0011] The reactive interface modifier is a compound that can react or co-crosslink with the host resin, heat-resistant reactive resin, and / or stress-buffering resin under ultraviolet light irradiation. By adjusting the type and amount of the reactive interface modifier, the interfacial bonding strength between the cured adhesive layer and the carrier substrate or wafer can be controlled, ensuring sufficient interfacial stability of the adhesive layer during high-temperature processing and enabling controllable peeling after cooling to room temperature.

[0012] In one embodiment, the heat-resistant reactive resin is selected from at least one of bismaleimide resin, maleimide-terminated resin, aromatic unsaturated polymer or prepolymer, photosensitive polyimide, (meth)acrylate-modified polyimide, acrylic-terminated polyimide oligomer, benzoxazine resin and cyanate ester resin.

[0013] In one embodiment, the bismaleimide resin is 4,4'-bismaleimide diphenylmethane or bismaleimide diphenyl ether; The maleimide-terminated resin is a maleimide-terminated polyimide; The aromatic unsaturated polymer is allyl bisphenol A or diallyl phthalate.

[0014] In one embodiment, the host resin is selected from at least one of high molecular weight acrylate polymers, ethylene copolymers, and rubber-modified polymers; wherein, the high molecular weight acrylate polymers are, for example, polymethacrylate, polyacrylate-methacrylate copolymers, or acrylate-styrene copolymers; and the ethylene copolymers are, for example, ethylene-vinyl acetate copolymers or ethylene-acrylate copolymers. The number average molecular weight of the main resin is 100,000 to 1,000,000.

[0015] In one embodiment, the stress-reducing resin is selected from at least one of acrylic-modified polyurethane, acrylic-modified polyester, acrylic-modified polyether, and high molecular weight acrylic elastomer. The number average molecular weight of the acrylic-modified polyurethane is 5,000 to 200,000, the number average molecular weight of the acrylic-modified polyester is 2,000 to 100,000, the number average molecular weight of the acrylic-modified polyether is 1,000 to 50,000, and the number average molecular weight of the high molecular weight acrylic elastomer is 100,000 to 2,000,000. The reactive interface modifier is selected from at least one of γ-methacryloxypropyltrialkoxysilane, γ-acryloxypropyltrialkoxysilane, vinyltrialkoxysilane, (meth)acrylate-terminated polysiloxane, vinyl-terminated polysiloxane, γ-glycidyl etheroxypropyltrialkoxysilane, isocyanate-functionalized silane, and epoxy-modified polysiloxane. The reactive interface modifier is present in a mass fraction of 0.1 to 3 parts.

[0016] In one embodiment, the photoinitiator is selected from at least one of α-hydroxy ketones, benzophenones, phosphonium salts, and iodonium salts; The photoinitiator is present in a mass fraction of 0.1 to 3 parts; The temporary bonding adhesive further includes an additive, wherein the additive is in the form of 0.1 to 1 part by weight, and the additive is selected from at least one of leveling agent, defoamer and tackifier; The temporary bonding adhesive also includes organic solvents.

[0017] A temporary bonding method includes the following steps: A temporary bonding adhesive as described in claim 1 is coated onto a carrier substrate to form an adhesive layer, and a wafer is stacked on the adhesive layer to obtain a semi-finished product. The semi-finished product is subjected to ultraviolet light pretreatment, which causes the adhesive layer to form a partially cross-linked network structure, thereby temporarily bonding and fixing the carrier substrate and the wafer to obtain a temporary bonded assembly. In the ultraviolet light pretreatment operation, the wavelength of the light source is 200nm~405nm, and the light dose is 200mJ / cm². 2 ~1500mJ / cm 2 The illumination time is 5s~180s; The temporary bonding assembly is placed at a temperature of 220°C to 320°C to perform semiconductor processing on the wafer, while the adhesive layer is further cured. After the above operations are completed, the temporary bonding assembly is cooled to room temperature, and the carrier substrate, the cured adhesive layer and the wafer are mechanically peeled off from each other.

[0018] The semiconductor processing performed on the wafer may include, but is not limited to, high-temperature baking, curing of dielectric or polymer layers, stress relief heat treatment, heat treatment during redistribution layer (RDL) formation, heat treatment during wafer thinning or back-side processing, and high-temperature processing steps involved in three-dimensional integration or fan-out packaging processes.

[0019] In one embodiment, the substrate is a transparent material.

[0020] In this invention, "partially cross-linked network structure" refers to a network structure formed after the adhesive layer is pretreated with ultraviolet light, with the degree of cross-linking between the uncross-linked state and the fully cured state.

[0021] The cross-linked network structure can be characterized by the gel fraction, preferably 30% to 90%. Within this cross-linking range, the adhesive layer can maintain morphological stability during high-temperature processing, while its interfacial bonding force decreases after processing and cooling to room temperature, thus facilitating mechanical peeling.

[0022] In this invention, the temporary bonding adhesive layer can reach a fully cured state after UV pretreatment and subsequent high-temperature treatment. Although both the high-temperature processing stage and the state after cooling to room temperature are in a cured state, the adhesive layer may still exhibit different mechanical and interfacial behaviors under different temperature conditions. One possible explanation is that under high-temperature conditions, some polymer segments in the cured adhesive layer are still in a relatively activated state, the overall modulus of the adhesive layer is relatively low, and the interface can maintain a large effective contact area, which is beneficial to maintaining the bonding stability between the carrier substrate and the wafer. However, after cooling to room temperature, as the temperature decreases, the modulus of the adhesive layer increases. At the same time, due to the difference in the coefficients of thermal expansion between the adhesive layer, the carrier substrate, and the wafer, the interface may generate certain thermal stress or interfacial stress concentration, resulting in a relative decrease in interfacial bonding force.

[0023] In one embodiment, the light dose during the ultraviolet pretreatment is 200 mJ / cm². 2 ~1500mJ / cm 2 The illumination time is 5s~180s; During the wafer processing operation, the temperature is 220℃~350℃ and the processing time is 15min~90min.

[0024] In specific embodiments, this temporary bonding adhesive of the present invention is applied to temporary bonding. Even when exposed to high temperatures above 220°C, it can still maintain sufficient bonding force to prevent wafer detachment. When cooled to room temperature, the bonding force decreases, thereby enabling controlled peeling. Attached Figure Description

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

[0026] in: Figure 1 This is a flowchart of a temporary bonding method according to one embodiment. Detailed Implementation

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

[0028] The present invention discloses a temporary bonding adhesive according to one embodiment, comprising the following components by weight: 30 to 70 parts of a host resin, 20 to 50 parts of a heat-resistant reactive resin, 5 to 20 parts of a stress-reducing resin, 0.1 to 3 parts of a reactive interface modifier, and 0.1 to 3 parts of a photoinitiator.

[0029] In this embodiment, the host resin is a high molecular weight host polymer with film-forming and initial adhesion properties, used as the continuous phase of the adhesive layer to provide good film-forming properties, matrix continuity, and system processing adaptability. Prior to UV pretreatment, the host resin is beneficial for providing the initial adhesion properties and morphological stability of the adhesive layer.

[0030] In this embodiment, the heat-resistant reactive resin, as part of a multi-component system, possesses a heat-resistant structure and reactive functional groups capable of participating in cross-linking reactions. Under ultraviolet light irradiation, the heat-resistant reactive resin can participate in the formation of a partially cross-linked network structure together with the host resin. During subsequent high-temperature processing, this heat-resistant reactive resin helps improve the modulus and structural stability of the adhesive layer under high-temperature conditions, thereby inhibiting softening, flow, or creep of the adhesive layer, rather than serving as the sole curing precursor in the system.

[0031] In this embodiment, the stress-buffering resin is a polymer material containing flexible segments, which is used to introduce a stress-buffering phase into the adhesive layer to alleviate the internal or interfacial stress generated in the adhesive layer during ultraviolet light pretreatment, high temperature treatment and subsequent peeling, thereby reducing the risk of the adhesive layer becoming brittle, failing at the interface or being uncontrollably damaged.

[0032] In this embodiment, the reactive interface modifier can react or co-crosslink with the host resin, heat-resistant reactive resin, and / or stress-reducing resin under ultraviolet light irradiation, thereby adjusting the interfacial bonding strength between the cured adhesive layer and the carrier substrate or wafer. As an example, the reactive interface modifier can be a reactive silicone compound and / or a silane compound.

[0033] In this embodiment, a photoinitiator is used to initiate a crosslinking reaction between the host resin and the heat-resistant reactive resin under ultraviolet light irradiation, thereby forming a partially crosslinked network structure in the adhesive layer.

[0034] Based on the application of this embodiment, when the temporary bonding adhesive is used for temporary bonding and undergoes high-temperature treatment above 220°C, the adhesive layer can maintain good structural integrity and interfacial bonding stability; after the high-temperature processing is completed and cooled to room temperature, the interfacial bonding force of the adhesive layer decreases, which is conducive to achieving overall or almost overall peeling by mechanical means.

[0035] Specifically, the temporary bonding adhesive of the present invention forms a partially cross-linked network structure with a gel fraction of 50% to 90% after ultraviolet light irradiation. The partially cross-linked network structure maintains bonding stability under high temperature conditions of 220°C to 320°C and can be mechanically peeled off after cooling to room temperature.

[0036] In one embodiment, the main resin may be selected from at least one of high molecular weight acrylate polymers, ethylene copolymers, and rubber-modified polymers; wherein, the high molecular weight acrylate polymers are, for example, polymethacrylate, polyacrylate-methacrylate copolymers, or acrylate-styrene copolymers; and the ethylene copolymers are, for example, ethylene-vinyl acetate copolymers or ethylene-acrylate copolymers. In one embodiment, the number average molecular weight of the main resin is 100,000 to 1,000,000.

[0037] In one embodiment, the heat-resistant reactive resin may be selected from at least one of bismaleimide resin, maleimide-terminated resin, aromatic unsaturated polymer or prepolymer, photosensitive polyimide, (meth)acrylate-modified polyimide, acrylic-terminated polyimide oligomer, benzoxazine resin and cyanate ester resin.

[0038] As an example, the bismaleimide resin may be 4,4'-bismaleimide diphenylmethane or bismaleimide diphenyl ether; the maleimide-terminated resin may be maleimide-terminated polyimide. The aromatic unsaturated polymer or prepolymer may be allyl bisphenol A or diallyl phthalate.

[0039] In one embodiment, the stress-reducing resin may be selected from at least one of acrylic-modified polyurethane, acrylic-modified polyester, acrylic-modified polyether, and high molecular weight acrylic elastomer.

[0040] For example, the number average molecular weight of acrylic-modified polyurethane can be 5,000 to 200,000, the number average molecular weight of acrylic-modified polyester can be 2,000 to 100,000, the number average molecular weight of acrylic-modified polyether can be 1,000 to 50,000, and the number average molecular weight of high molecular weight acrylic elastomer can be 100,000 to 2,000,000.

[0041] In this embodiment, the above-mentioned components may exist in the adhesive system in the form of homogeneous phase, phase separation or interpenetrating network, and the specific form is not limited.

[0042] In one embodiment, the reactive interface modifier may be selected from at least one of γ-methacryloxypropyltrialkoxysilane, γ-acryloxypropyltrialkoxysilane, vinyltrialkoxysilane, (meth)acrylate-terminated polysiloxane, vinyl-terminated polysiloxane, γ-glycidyl etheroxypropyltrialkoxysilane, isocyanate-functionalized silane, and epoxy-modified polysiloxane.

[0043] Preferably, in this embodiment, the reactive interface modifier is 0.5 to 3 parts by mass.

[0044] In one embodiment, the photoinitiator may be selected from at least one of α-hydroxy ketones, benzophenones, phosphonium salts, and iodonium salts.

[0045] Preferably, in this embodiment, the photoinitiator is 0.5 to 3 parts by mass.

[0046] In one embodiment, the temporary bonding adhesive may further include additives and / or organic solvents. The additives are, for example, selected from at least one of leveling agents, defoamers, and tackifiers, and are used in an amount, for example, 0.01 to 1 part. The specific types and amounts of additives and organic solvents can be selected according to actual process requirements to meet the requirements of spin coating, blade coating, and other processing techniques.

[0047] Combination Figure 1 The present invention also discloses a temporary bonding method, which includes the following steps: S10. The above-mentioned temporary bonding adhesive is coated on the carrier substrate to form an adhesive layer, and a wafer is stacked on the adhesive layer to obtain a semi-finished product.

[0048] In this embodiment, the carrier substrate can be a transparent material so that ultraviolet light can pass through the carrier substrate to irradiate the adhesive layer during the subsequent ultraviolet light pretreatment process.

[0049] For example, the carrier substrate can be transparent glass.

[0050] Adhesives can be applied by spin coating, scraping, or other methods.

[0051] In this embodiment, the thickness of the adhesive layer can be, for example, 10 μm to 200 μm, and the specific thickness can be adjusted according to actual process requirements.

[0052] S20. The semi-finished product obtained in S10 is subjected to ultraviolet light pretreatment to form a partially cross-linked network structure in the adhesive layer, thereby temporarily bonding and fixing the carrier substrate to the wafer to obtain a temporary bonding combination.

[0053] In this embodiment, the ultraviolet light pretreatment uses ultraviolet light with a wavelength of 200 nm to 405 nm, and the light dose is, for example, 200 mJ / cm² to 1500 mJ / cm², and the light exposure time is, for example, 5 s to 180 s.

[0054] By controlling the energy and time of ultraviolet light irradiation, the adhesive layer is made into a partially cross-linked network structure with a cross-linking degree between the uncross-linked state and the fully cured state. In this partially cross-linked state, the adhesive layer can maintain the continuity and stability of the film structure during subsequent high-temperature processing, and is conducive to peeling after the high-temperature process is completed and cooled. The energy, wavelength, and duration of ultraviolet irradiation are controlled, ensuring that the adhesive layer will not flow at high temperatures due to insufficient cross-linking, nor will it become difficult to peel due to excessive cross-linking.

[0055] In one embodiment, the gel fraction of the partially cross-linked network structure formed after the adhesive layer is pretreated with ultraviolet light is 50% to 90%.

[0056] More preferably, in this embodiment, the gel fraction of the partially cross-linked network structure formed after the adhesive layer is pretreated with ultraviolet light is 61% to 89%.

[0057] The partial cross-linking state can be characterized by the gel fraction, and the method for determining the gel fraction is not limited to a specific test method.

[0058] S30. The temporary bonding combination obtained in S20 is placed at a temperature of 220℃~320℃ to perform semiconductor processing on the wafer, while the adhesive layer is further cured.

[0059] In this embodiment, under the high-temperature conditions required for semiconductor processing, the adhesive layer can meet the requirements for structural integrity and interfacial bonding stability during the processing.

[0060] Semiconductor processing of wafers can include: high-temperature baking, curing of dielectric or polymer layers, stress relief heat treatment, heat treatment during redistribution layer (RDL) formation, heat treatment during wafer thinning or back-side processing, and high-temperature processing steps involved in three-dimensional integration or fan-out packaging processes.

[0061] S40. After the operation in S30 is completed, the above temporary bonding assembly is cooled to room temperature, and the carrier substrate, the cured adhesive layer and the wafer are peeled off from each other by mechanical means.

[0062] In this embodiment, after cooling to room temperature, the interfacial bonding force of the adhesive layer decreases, which facilitates the overall or nearly overall peeling by mechanical means, and the residual adhesive can be effectively controlled.

[0063] By implementing the above method, the partially cross-linked network structure formed by ultraviolet light pretreatment enables the temporary bonding assembly to maintain sufficient bonding stability under high temperature conditions above 220°C, and to achieve controllable peeling after the process is completed and cooled. This method is suitable for semiconductor packaging, wafer thinning and related high temperature temporary bonding processes.

[0064] The following are specific examples.

[0065] In the specific embodiments, the source information of various raw materials used is as follows: high molecular weight acrylate resin was purchased from Nanbao Company (brand name SD-488, Mn≈400000); allyl bisphenol A was purchased from Maclean Company (purity 90%, product number D888680); acrylic modified polyurethane was purchased from Haohui New Materials Company (brand name CR92958, acrylate functionality 2); the reactive interface modifier was organosilicon diacrylate, purchased from Zhanxin Resin Company (brand name EBECRYL 350); the photoinitiator was 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, purchased from Jiangxi Lote Chemical Co., Ltd.

[0066] Examples 1-3 and Comparative Examples 1-4 According to Table 1 below, after mixing the raw material components, a temporary bonding adhesive is obtained.

[0067] Table 1: Formulations and Process Conditions of Examples and Comparative Examples Example 1 Add 50 parts by weight of high molecular weight acrylic resin (Nanbao, SD-488) as the main resin, 40 parts by weight of allyl bisphenol A (Maclean, D888680) as a heat-resistant reactive resin, and 10 parts by weight of difunctional acrylic-modified polyurethane (Haohui, CR92958) as a stress-buffering resin to a container. Further, add 1.5 parts by weight of difunctional siloxane acrylate (EBECRYL 350) as a reactive interface modifier and 1.5 parts by weight of 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (Jiangxi Lote Chemical) as a photopolymerization initiator, mix thoroughly, and a temporary bonding adhesive can be prepared.

[0068] Temporary bonding adhesive was applied to the surface of a glass substrate measuring 25 cm long, 2 cm wide, and 5 mm thick, forming an adhesive layer with a thickness of 40 μm. Subsequently, wafers of the same size were stacked on the adhesive layer to obtain a semi-finished product. The semi-finished product was irradiated with ultraviolet light (UVPB100AP, USA) at a center wavelength of approximately 365 nm and a light intensity of approximately 10 mW / cm², causing the adhesive layer to enter a partially cross-linked state. This formed a partially cross-linked network within the adhesive layer, thereby bonding and fixing the glass substrate and wafer together. This temporary bonding assembly was obtained by forming a partially cross-linked network structure within the adhesive layer and temporarily bonding and fixing the glass substrate and wafer together.

[0069] The operations of Examples 2-3 and Comparative Examples 1-4 are basically the same as those of Example 1, except that the composition of the temporary bonding adhesive is changed as shown in Table 1. Otherwise, the same operations as in Example 1 are performed to obtain the temporary bonding adhesive.

[0070] It should be noted that during the testing process, 12 samples of the temporary bonding adhesive obtained in each embodiment and comparative example were repeated for parallel comparison. In subsequent tests, 3 samples were taken for testing.

[0071] Test case The temporary bonding adhesives obtained in the examples and comparative examples were evaluated using the following methods. The results are shown in Tables 2-3.

[0072] (1) Determination of gel fraction In this invention, the partial crosslinking state of the adhesive layer can be characterized by the gel fraction. The gel fraction can be determined by the swelling-extraction method, following these steps: Samples of the temporary bonding materials of the examples and comparative examples after UV pretreatment were taken. Subsequently, the temporary fixation material was cut into planar test pieces of approximately 50 mm × 100 mm to obtain samples for testing. The test pieces were immersed in toluene at 25°C for 24 hours, then removed from the toluene and dried at 110°C for 1 hour. The weight of the dried test pieces was measured, and the gel fraction was calculated using the following formula (1). It should be noted that a release film for protection was laminated on the adhesive surface during the cutting of the test pieces, and the release film needs to be peeled off before immersion in toluene.

[0073] Gel fraction (weight %) = 100 × (W2 - W0) / (W1 - W0) Where W0 is the weight of the substrate in the test piece; W1 is the weight of the test piece before impregnation; and W2 is the weight of the test piece after impregnation and drying.

[0074] (2) Evaluation of voids and bulges The appearance of the temporary bonding adhesive after UV curing and heating at 270°C is evaluated by visually observing whether there are gaps or bulges between the wafer and the glass plate.

[0075] (3) Peelability and adhesion tests at 25°C before and after heat treatment at 270°C for 30 minutes. A 180° peel test was conducted on the examples and comparative examples before and after the above treatment at 25°C and a tensile speed of 300 mm / min. The surface of the glass slides after peeling was visually observed, and the presence and area of ​​residual adhesive were evaluated.

[0076] Table 2: Gel fraction and adhesive strength before and after treatment in the examples and comparative examples As can be seen from Table 2, the temporary bonding adhesives prepared in Examples 1-3, when used for temporary bonding, can firmly bond the glass substrate and the wafer together after UV pretreatment, and the adhesive strength decreases significantly after heat treatment, thus facilitating the mechanical peeling of the temporary bonding assembly.

[0077] Table 3: Comparison of Performance and Peeling Behavior between Examples and Comparative Examples As can be seen from Table 3, the temporary bonding combination of the temporary bonding adhesives prepared by Examples 1-3, after being heat-treated at 270°C, retains the integrity of the adhesive layer during the high-temperature treatment and can be peeled off as a whole after cooling, with no obvious adhesive residue, thus achieving controllable peeling.

[0078] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., 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 the embodiments of the present 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 the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0079] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0080] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0081] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-temperature resistant temporary bonding adhesive for semiconductor processes, characterized in that, According to the mass fractions, it includes the following components: 30 to 70 parts of main resin, 20 to 50 parts of heat-resistant reactive resin, 5 to 20 parts of stress-absorbing resin, 0.1 to 3 parts of reactive interface modifier, and 0.1 to 3 parts of photoinitiator. The main resin is a high molecular weight main polymer with film-forming and initial adhesion properties, which is used to impart initial tack to the adhesive and provide structural support before the crosslinking reaction occurs. The heat-resistant reactive resin has a heat-resistant structure and a reactive structure that can participate in cross-linking reactions. The heat-resistant reactive resin is used to form a partially cross-linked network with the main resin component under ultraviolet light irradiation. The stress-buffering resin is a polymer with flexible chain segments, used to introduce a stress-buffering phase into the curing system to reduce interfacial or internal stress generated during high-temperature treatment and peeling. The reactive interface modifier is used to react and / or co-crosslink with other components under ultraviolet light, thereby adjusting the interfacial bonding strength of the cured product to achieve controllable peeling. The temporary bonding adhesive forms a partially cross-linked network structure with a gel fraction of 50% to 90% after being irradiated with ultraviolet light. The partially cross-linked network structure maintains bonding stability under high temperature conditions of 220℃ to 350℃ and can be mechanically peeled off after cooling to room temperature.

2. The temporary bonding adhesive according to claim 1, characterized in that, The heat-resistant reactive resin is selected from at least one of bismaleimide resin, maleimide-terminated resin, aromatic unsaturated polymer or prepolymer, photosensitive polyimide, (meth)acrylate-modified polyimide, acrylic-terminated polyimide oligomer, benzoxazine resin and cyanate ester resin.

3. The temporary bonding adhesive according to claim 2, characterized in that, The bismaleimide resin is 4,4'-bismaleimide diphenylmethane or bismaleimide diphenyl ether; The maleimide-terminated resin is a maleimide-terminated polyimide; The aromatic unsaturated resin is allyl bisphenol A or diallyl phthalate.

4. The temporary bonding adhesive according to claim 1, characterized in that, The main resin is selected from at least one of high molecular weight acrylate polymers, ethylene copolymers, and rubber-modified polymers; wherein, the high molecular weight acrylate polymers are, for example, polymethacrylate, polyacrylate-methacrylate copolymers, or acrylate-styrene copolymers; and the ethylene copolymers are, for example, ethylene-vinyl acetate copolymers or ethylene-acrylate copolymers. The number average molecular weight of the main resin is 100,000 to 1,000,000.

5. The temporary bonding adhesive according to claim 1, characterized in that, The stress-reducing resin is selected from at least one of acrylic-modified polyurethane, acrylic-modified polyester, acrylic-modified polyether, and high molecular weight acrylic elastomer. The number average molecular weight of the acrylic-modified polyurethane is 5,000 to 200,000, the number average molecular weight of the acrylic-modified polyester is 2,000 to 100,000, the number average molecular weight of the acrylic-modified polyether is 1,000 to 50,000, and the number average molecular weight of the high molecular weight acrylic elastomer is 100,000 to 2,000,000. The reactive interface modifier is selected from at least one of γ-methacryloxypropyltrialkoxysilane, γ-acryloxypropyltrialkoxysilane, vinyltrialkoxysilane, (meth)acrylate-terminated polysiloxane, vinyl-terminated polysiloxane, γ-glycidyl etheroxypropyltrialkoxysilane, isocyanate-functionalized silane, and epoxy-modified polysiloxane.

6. The temporary bonding adhesive according to claim 5, characterized in that, The photoinitiator is selected from at least one of α-hydroxy ketones, benzophenones, phosphonium salts, and iodonium salts; The temporary bonding adhesive further includes an additive, wherein the additive is in the form of 0.1 to 1 part by weight, and the additive is selected from at least one of leveling agent, defoamer and tackifier; The temporary bonding adhesive also includes organic solvents.

7. A temporary bonding method, characterized in that, Includes the following steps: A temporary bonding adhesive as described in any one of claims 1 to 6 is coated onto a carrier substrate to form an adhesive layer, and a wafer is stacked on the adhesive layer to obtain a semi-finished product. The semi-finished product is subjected to ultraviolet light pretreatment, which causes the adhesive layer to form a partially cross-linked network structure, thereby temporarily bonding and fixing the carrier substrate and the wafer to obtain a temporary bonded assembly. In the ultraviolet light pretreatment operation, the wavelength of the light source is 200nm~405nm, and the light dose is 200mJ / cm². 2 ~1500mJ / cm 2 The illumination time is 5s~180s; The temporary bonding assembly is placed at a temperature of 220°C to 350°C to perform semiconductor processing on the wafer, while the adhesive layer is further cured. After the above operations are completed, the temporary bonding assembly is cooled to room temperature, and the carrier substrate, the cured adhesive layer and the wafer are mechanically peeled off from each other.

8. The temporary bonding method according to claim 7, characterized in that, The substrate is a transparent material.

9. The temporary bonding method according to claim 7, characterized in that, The gel fraction of the partially cross-linked network structure formed after UV pretreatment of the adhesive layer is 50% to 90%.

10. The temporary bonding method according to claim 9, characterized in that, In the ultraviolet light pretreatment operation, the illumination time is 90s~180s; In the semiconductor processing operation of the wafer, the processing time is 15 min to 90 min.

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