Temporary bonding laser release material and application thereof

Abstract

The invention discloses a temporary bonding laser release material and application thereof. The temporary bonding laser release material comprises polyimide containing active sites, a reactive diluent containing cross-linkable groups, and an initiator or a catalyst, the polyimide is dissolved in the reactive diluent, and the initiator or the catalyst is used for initiating a cross-linking reaction between the reactive diluent and the polyimide. The temporary bonding laser release material does not contain a solvent, the reactive diluent is used for replacing the solvent, polyimide can be dissolved, the temporary bonding laser release material and polyimide can be subjected to a cross-linking reaction to be cured, the problems caused by the residual solvent are solved fundamentally, the wafer processing reliability is remarkably improved, the film forming time is shortened, and the production efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of advanced packaging materials, specifically relating to a temporary bonded laser release material and its application. Background Technology

[0002] In advanced semiconductor packaging processes, such as 3D stacked packaging, fan-out wafer-level packaging (FOWLP), and 2.5D / 3D packaging using through silicon via (TSV) technology, the demand for ultra-thin wafers is becoming increasingly significant. During wafer fabrication, to meet the heat dissipation and packaging requirements of the chip, it is often necessary to reduce the wafer to a specific thickness.

[0003] However, ultrathin wafers are flexible, fragile, and prone to warping and bending. Direct processing can easily lead to wafer breakage, severely impacting chip manufacturing yield, processing accuracy, and packaging precision. To address this challenge, temporary bonding technology has emerged. Temporary bonding / debonding is the core of ultrathin wafer technology. It uses temporary bonding adhesive to temporarily bond the device wafer to a rigid carrier (such as silicon, glass, or sapphire substrate), providing sufficient mechanical support and increasing the wafer's mechanical toughness. This ensures the wafer can be safely and smoothly processed in subsequent processes such as photolithography, etching, passivation, electroplating, and reflow soldering. After all processes are completed, the carrier wafer is separated from the device wafer using a specific debonding method, resulting in a intact ultrathin device wafer.

[0004] Among various debonding methods, ultraviolet laser debonding stands out due to its high efficiency, room temperature operation, and low stress, making it a significant research hotspot and development trend in the field of temporary bonding technology. Temporary bonding material systems based on ultraviolet laser debonding typically use a combination of laser-emitting materials and adhesive layer materials. Polyimide materials, with their excellent thermal stability, chemical stability, mechanical properties, good film-forming ability, and good ultraviolet absorption capacity, are among the ideal laser-emitting materials for temporary bonding.

[0005] In practical applications, polyimide materials used for temporary bonding of laser-emitting materials have a high glass transition temperature and lack thermoforming capabilities. Therefore, they cannot be used alone as an adhesive layer to bond wafers and carriers. They are usually used in combination with other resins. Specifically, the polyimide material is spin-coated onto the glass carrier as the laser-emitting layer, while other resins with bonding and thermoforming capabilities (such as polyacrylate) are spin-coated onto the wafer as an adhesive layer. The two are then bonded together by vacuum thermoforming. During debonding, ultraviolet laser light enters from the glass carrier. The polyimide at the laser-emitting layer / glass carrier interface absorbs the ultraviolet light and decomposes to generate bubbles. The bubbles gradually grow until the interface separates, and the debonding is completed.

[0006] Polyimide temporary bonding adhesives, used as temporary bonding materials for laser emission, are typically in solution form. This involves dissolving polyimide in a high-boiling-point solvent, such as NMP (N-methylpyrrolidone), DMAc (dimethylacetamide), or DMF (N,N-dimethylformamide), to form a homogeneous solution. In application, this solution is spin-coated onto a substrate or wafer surface using methods such as spin coating. The solvent is then removed by baking to form a film, and finally, the wafer and substrate are bonded together using hot pressing.

[0007] However, the application of this solvent-based temporary bonded laser-emitting material is limited. Firstly, due to the dense molecular structure of polyimide after film formation and the high boiling point of its commonly used solvents, complete solvent removal during baking is difficult. If solvent residue remains, it will transform from a liquid to a gaseous state due to heat during subsequent high-temperature and vacuum processes such as PECVD thin film deposition and reflow soldering. This gaseous state gradually forms voids at the interface between the temporary bonded laser-emitting material and the substrate, affecting wafer processing and even causing interface delamination failure. This significantly impacts wafer processing yield and product reliability. Secondly, to remove residual solvent as much as possible, prolonged and high-temperature baking is usually required, for example, baking at a temperature not lower than 280°C for at least 20 minutes. This not only places higher temperature resistance requirements on production equipment but also significantly extends the process cycle and reduces overall production efficiency. Summary of the Invention

[0008] The purpose of this invention is to solve the technical problems caused by the use of high-boiling-point solvents in existing temporary bonded laser emitting materials. This invention provides a solvent-free temporary bonded laser emitting material and its application.

[0009] The objective of this invention is achieved through the following technical solution.

[0010] In a first aspect, the present invention provides a temporary bonding adhesive comprising a polyimide containing active sites, a reactive diluent with crosslinkable groups, and an initiator or catalyst; wherein the polyimide is dissolved in the reactive diluent, and the initiator or catalyst is used to initiate a crosslinking reaction between the reactive diluent and the polyimide.

[0011] Furthermore, the active sites in the polyimide include at least one of hydroxyl, amino, and carbon-carbon double bonds.

[0012] Furthermore, the crosslinkable groups in the reactive diluent include at least one of epoxy groups, acrylate groups, vinyl groups, and isocyanate groups.

[0013] Furthermore, when the active site group in the polyimide is hydroxyl or amino, the crosslinkable group in the reactive diluent is epoxy and / or isocyanate group; and / or,

[0014] When the active site group in the polyimide is a carbon-carbon double bond, the crosslinkable group in the reactive diluent is an acrylate group and / or a vinyl group.

[0015] Furthermore, when the crosslinkable groups in the reactive diluent are epoxy-based, the initiator is a cationic initiator, and the cationic initiator includes at least one of boron trifluoride-ethylamine complex, diaryliodonium hexafluorophosphate, and triarylthionium hexafluorophosphate; and / or,

[0016] When the crosslinkable groups in the reactive diluent are acrylates and / or vinyl groups, the initiator is a free radical initiator, which is a thermal initiator or a photoinitiator. The thermal initiator includes benzoyl peroxide or di-tert-butyl peroxide; the photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone or 1-hydroxycyclohexylphenyl ketone; and / or...

[0017] When the crosslinkable group in the active diluent is an isocyanate group, the catalyst is an organotin catalyst.

[0018] Furthermore, the main chain of the polyimide contains ether bonds or rigid groups, and the rigid groups include at least one of fluorenyl or indene structures.

[0019] Furthermore, the temporary bonded laser release material also includes additives, which are leveling agents and / or adhesion promoters.

[0020] Furthermore, by weight, the temporary bonded laser-emitting material comprises 20-79 parts of polyimide, 20-79 parts of reactive diluent, 0.1-5.0 parts of initiator or catalyst, and 0-2.5 parts of additives.

[0021] Furthermore, the leveling agent is an organosilicon or fluorocarbon leveling agent, and the amount of the leveling agent added is 0 to 0.5 parts of the total amount; and / or

[0022] The adhesion promoter is a silane coupling agent, and the amount of the adhesion promoter added is 0 to 2.0 parts of the total amount.

[0023] In a second aspect, the present invention provides the application of the temporary bonding laser release material as described in the first aspect, wherein the temporary bonding laser release material is used in wafer processing to temporarily bond the wafer to a carrier.

[0024] Compared with the prior art, the present invention has the following beneficial effects.

[0025] 1) This invention fundamentally solves the problem caused by residual solvents, significantly improving the reliability of wafer processing. The temporary bonded laser-emitting material of this invention is solvent-free, using an active diluent instead. The active diluent not only dissolves the polyimide, but also, during the film-forming stage, under the action of an initiator or catalyst, undergoes a cross-linking reaction with the polyimide and solidifies, thus making the active diluent a "component" of the final film, rather than being evaporated and removed like traditional solvents. This fundamentally eliminates the risk of voids or interface separation failure at the interface between the laser-emitting layer and the carrier substrate due to residual solvent evaporation during subsequent high-temperature and vacuum processes, ensuring interface integrity and stability during wafer processing.

[0026] 2) Shorten film formation time and improve production efficiency. Compared with traditional solvent-based temporary bonded laser emitting materials that require long-term high-temperature baking to remove solvent, the temporary bonded laser emitting material of the present invention is cured through a cross-linking reaction and only requires a short period of thermal curing or photocuring to form a film. For example, the thermal curing time can be shortened to 10 minutes and the photocuring time can be shortened to a few seconds, which greatly shortens the process time and improves the overall production efficiency.

[0027] 3) Maintaining excellent temporary bonding / debonding. The temporary bonding laser-emitting material of this invention solves the solvent residue problem, while the laser-emitting layer formed after curing still possesses excellent ultraviolet laser absorption and decomposition properties, enabling efficient and low-stress laser debonding. Furthermore, the residue on the carrier after debonding is easily cleaned, meeting the requirements for temporary bonding / debonding. Moreover, by optimizing the ratio of polyimide to reactive diluent, the threshold debonding energy can be reduced, minimizing wafer warping and cracking, and improving laser lifespan and debonding efficiency. Detailed Implementation

[0028] 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.

[0029] In a first aspect, the present invention provides a temporary bonding adhesive comprising a polyimide containing active sites, a reactive diluent with crosslinkable groups, and an initiator or catalyst; wherein the reactive diluent is used to dissolve the polyimide, and the initiator or catalyst is used to initiate a crosslinking reaction between the reactive diluent and the polyimide.

[0030] The temporary bonded laser-emitting material of this invention is solvent-free, using an active diluent instead. This active diluent not only dissolves the polyimide, but also, during the film-forming stage, undergoes a cross-linking reaction with the polyimide under the action of an initiator or catalyst, solidifying it. This makes the active diluent an integral part of the final film formation, rather than being evaporated and removed like traditional solvents. This fundamentally eliminates the risk of voids or interface separation failure at the laser-emitting layer-carrier interface due to residual solvent evaporation during subsequent high-temperature and vacuum processes, ensuring interface integrity and stability during wafer fabrication.

[0031] In some specific embodiments, the active sites in the polyimide are selected from at least one of hydroxyl (-OH), amino (-NH2), and carbon-carbon double bonds (C=C). Thus, the polyimide and the reactive diluent can be crosslinked via ring-opening reactions, free radical polymerization, or condensation reactions.

[0032] In some specific embodiments, the crosslinkable groups in the reactive diluent are selected from at least one of epoxy groups, acrylate groups, vinyl groups, and isocyanate groups. Specifically, the reactive diluent can be an alicyclic epoxy resin (GT301), bisphenol A epoxy resin (E51), epoxy acrylate (EA-600), trimethylolpropane triacrylate, N-vinylpyrrolidone, diphenylmethane diisocyanate, etc.

[0033] To achieve crosslinking between the polyimide and the reactive diluent, the polyimide of the present invention contains specific active sites, and the reactive diluent contains crosslinkable groups capable of reacting with them. Specifically, when the active sites in the polyimide are hydroxyl and / or amino groups, the crosslinkable groups in the reactive diluent are epoxy and / or isocyanate groups. When the active sites in the polyimide are carbon-carbon double bonds, the crosslinkable groups in the reactive diluent are acrylate and / or vinyl groups.

[0034] In some specific embodiments, the crosslinkable groups in the reactive diluent are epoxy-based, and in this case, the initiator used is a cationic initiator; the cationic initiator includes at least one of boron trifluoride-ethylamine complex, diaryliodonium hexafluorophosphate, and triarylthionium hexafluorophosphate. The cationic initiator is preferably boron trifluoride-ethylamine complex. When the reactive diluent reacts with polyimide, if the crosslinkable groups are epoxy-based, the cationic initiator exhibits higher reactivity.

[0035] In some specific embodiments, the crosslinkable groups in the reactive diluent are acrylates and / or vinyl groups, in which case the initiator used is a free radical initiator. The free radical initiator is a thermal initiator or a photoinitiator; the thermal initiator is preferably benzoyl peroxide or di-tert-butyl peroxide; the photoinitiator is preferably 2-hydroxy-2-methyl-1-phenylpropanone or 1-hydroxycyclohexylphenyl ketone. When the reactive diluent reacts with polyimide, if the crosslinking groups are acrylates or vinyl groups containing double bonds, a free radical initiator is needed to generate free radicals to trigger the polymerization reaction between the double bonds.

[0036] In some specific embodiments, the crosslinkable group in the active diluent is an isocyanate group. In this case, the catalyst used is an organotin catalyst, preferably dibutyltin dilaurate. When the active diluent reacts with polyimide, if the crosslinking group is epoxy-based, the organotin catalyst exhibits higher catalytic activity.

[0037] In some specific embodiments, the main chain of the polyimide contains ether bonds or rigid groups, wherein the rigid groups include at least one of fluorene or indane structures. This ensures high solubility of the polyimide in reactive diluents and its washability after debonding.

[0038] In some specific embodiments, the temporary bonded laser-release material further includes additives, namely leveling agents and / or adhesion promoters. Adding leveling agents can improve the uniformity of film thickness; adding adhesion promoters can improve the bonding strength of the adhesive film to the carrier plate.

[0039] In some specific embodiments, the temporary bonded laser-emitting material comprises, by weight, 20-79 parts of polyimide, 20-79 parts of reactive diluent, 0.1-5.0 parts of initiator or catalyst, and 0-2.5 parts of additives. High-energy lasers and their thermal effects may cause wafer warping and cracking. To reduce the threshold debonding energy, preferably, the temporary bonded laser-emitting material comprises 50-75 parts of polyimide, 24-49 parts of reactive diluent, 1-5 parts of initiator or catalyst, and 0-2.5 parts of additives.

[0040] In some specific embodiments, the leveling agent is an organosilicon or fluorocarbon leveling agent, and the amount of the leveling agent added is 0 to 0.5 parts of the total amount; the adhesion promoter is a silane coupling agent, and the amount of the adhesion promoter added is 0 to 2.0 parts of the total amount. Appropriately increasing the leveling agent is beneficial to improving the uniformity of film thickness, and appropriately increasing the adhesion promoter is beneficial to improving the bonding strength of the adhesive film to the carrier plate.

[0041] The method for preparing the temporary bonded laser-emitting material of the present invention comprises the following steps:

[0042] 1) Polyamic acid is obtained by dissolving a diamine containing an active site and a dianhydride in a high-boiling-point solvent (such as NMP, DMAc, DMF, etc.); at least one monomer of the diamine and / or dianhydride may contain an active site, wherein the active site is selected from at least one of hydroxyl (-OH), amino (-NH2), and carbon-carbon double bond (C=C);

[0043] 2) Coat the polyamic acid film with a scraper, then treat it at high temperature to remove the solvent;

[0044] 3) Polyimide is obtained by thermal imidization of polyamic acid after solvent removal;

[0045] 4) Dissolve polyimide in an active diluent and add an initiator or catalyst. Preferably, a leveling agent and / or an adhesion promoter can be added simultaneously. Stir until homogeneous, then degas under vacuum to obtain a temporary bonded laser-emitting material.

[0046] In step 1), the temperature of the copolymerization reaction is 0~40℃ and the time is 7~24h; in step 2), the temperature of the high-temperature treatment is 120~200℃ and the time is 2~12h; in step 3), the temperature of the thermal imidization is 250~350℃ and the time is 0.5~10h.

[0047] The diamines used in the preparation of polyimides include 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(3-aminophenyl)fluorene, 9,9-bis(3-hydroxy-4-aminophenyl)fluorene, 1,1-bis(4-aminophenyl)cyclohexane, 5(6)-amino-1-(4-aminophenyl)-1,3,3-trimethylindene, 3,3-bis(4-aminophenyl)phthalide, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 2,2'-diaminodiphenyl sulfide, 2,2'-bis(4-aminophenoxyphenyl)propane, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 2,2'-bis[4-(4-aminophenoxyphenyl)]propane, 1,4-phenylene di[[4-(4-aminophenoxy)phenyl] ketone], 4,4'-bis(4-aminophenoxy)benzophenone, 4,4'-bis(3-aminophenoxy)benzophenone, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-diamino-4"-hydroxytriphenylmethane, 3,3'-diaminobenzidine, 4,4'-diaminostilbene-2,2'-disulfonic acid, bis(4 4,4'-diaminophenyl)fumarate, allyl-4,4'-diaminodiphenyl ether, etc.; the above diamines can be used alone or in any combination. The preferred diamine is at least one of 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(3-aminophenyl)fluorene, 9,9-bis(3-hydroxy-4-aminophenyl)fluorene, 4,4'-diaminodiphenyl ether, 3,3'-diaminobenzidine, and 4,4'-diaminostilbene-2,2'-disulfonic acid.

[0048] The dianhydrides used in the preparation of polyimides may include 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,2,3',3-biphenyltetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 4,4'-biphenyl ether dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, bisphenol A type diether dianhydride, 4,4'-terephthalodioxydiphthalic anhydride, bis(4-carboxyphenyl)itaconate dianhydride, and vinylpyromellitic dianhydride. These dianhydrides can be used individually or in any combination. Preferably, at least one of 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 4,4'-biphenyl ether dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, and bisphenol A type diether dianhydride is used.

[0049] In a second aspect, the present invention provides the application of the temporary bonding laser release material as described in the first aspect, wherein the temporary bonding laser release material is used in wafer processing to temporarily bond the wafer to a carrier.

[0050] Temporary bonding: Temporary bonding laser-emission materials were spin-coated onto 500-micron UV-cured fused silica glass substrates at 1000-3000 rpm for 15-40 seconds using a spin coater to form laser-emission layers. Through process control, the dry film thickness of the temporary bonding laser-emission materials was consistently 1 micron. A commercially available temporary bonding adhesive (Shenzhen Huaxun Semiconductor Materials Co., Ltd., model TB4180) was spin-coated onto a 500-micron thick wafer surface at 500 rpm for 15 seconds using a spin coater. The wafer was then placed on a hot plate and baked at 110°C for 10 minutes, followed by baking at 220°C for 20 minutes, to form a 50-micron thick adhesive layer. After spin-coating, the glass substrate was placed on a hot plate and baked at 180°C for 10 minutes for thermosetting; alternatively, the glass substrate was placed under a UV LED with a wavelength of 365nm and a power of 300mW / cm². 2 Under irradiation for 10 seconds, photocuring is performed. The glass substrate is aligned vertically with the wafer, with the laser-released layer and the adhesive layer facing each other, at 20 kgf / in. 2 Under pressure, vacuum hot-press bonding at 180℃ for 5 minutes yields bonded pairs of temporary bonded adhesive.

[0051] Debonding: The bonded pairs were irradiated from the UV fused quartz glass substrate side using a solid-state UV laser in an S-shaped scanning pattern, starting at 100 mJ / cm². 2 Initially, the light intensity is gradually increased. The polyimide at the interface of the laser emission layer / glass substrate absorbs ultraviolet light and decomposes to produce bubbles. The bubbles gradually grow until the interface separates and the debonding is completed.

[0052] The specific embodiments of the present invention will be further explained and described below through examples and comparative examples.

[0053] 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.

[0054] Example 1

[0055] The temporary bonded laser-emitting material of this embodiment comprises 20 parts of polyimide containing active sites, 79 parts of active diluent and 1 part of catalyst.

[0056] The active sites of the polyimide are hydroxyl and amino groups. The diamine used in the copolymerization reaction is selected as 9,9-bis(3-hydroxy-4-aminophenyl)fluorene and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1. The dianhydride used is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, and the molar ratio of dianhydride to diamine is 1:1. The active diluent is diphenylmethane diisocyanate, and the catalyst is dibutyltin dilaurate.

[0057] Example 2

[0058] The temporary bonded laser-emitting material of this embodiment comprises 20 parts of polyimide containing active sites, 79 parts of active diluent and 1 part of catalyst.

[0059] The active site of the polyimide is an amino group. The diamine used in the copolymerization reaction is selected as 3,3'-diaminobenzidine and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1. The dianhydride used is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, and the molar ratio of dianhydride to diamine is 1:1. The active diluent is diphenylmethane diisocyanate, and the catalyst is dibutyltin dilaurate.

[0060] Example 3

[0061] The temporary bonded laser-emitting material of this embodiment comprises 77 parts of polyimide containing active sites, 20 parts of reactive diluent and 3 parts of initiator.

[0062] The active sites of the polyimide are hydroxyl and amino groups. The diamine used in the copolymerization reaction is selected as 9,9-bis(3-hydroxy-4-aminophenyl)fluorene and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1. The dianhydride is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in a molar ratio of 1:1. The molar ratio of dianhydride to diamine is 1:1. The reactive diluent is a mixture of alicyclic epoxy resin (GT301) and bisphenol A epoxy resin (E51) in a mass ratio of 1:1. The initiator is boron trifluoride-ethylamine complex.

[0063] Example 4

[0064] The temporary bonded laser release material of this embodiment comprises 20 parts of polyimide containing active sites, 75 parts of reactive diluent and 5 parts of initiator.

[0065] The active site of the polyimide is a carbon-carbon double bond. The diamine used in the copolymerization reaction is selected as 4,4'-diaminostilbene-2,2'-disulfonic acid and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1. The dianhydride is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in a molar ratio of 1:1. The molar ratio of dianhydride to diamine is 1:1. The reactive diluent is a mixture of epoxy acrylate (EA-600) and trimethylolpropane triacrylate in a mass ratio of 2:1. The initiator is di-tert-butyl peroxide.

[0066] Example 5

[0067] The temporary bonded laser release material of this embodiment comprises 20 parts of polyimide containing active sites, 75 parts of reactive diluent and 5 parts of initiator.

[0068] The active site of the polyimide is a carbon-carbon double bond. The diamine used in the copolymerization reaction is selected as 4,4'-diaminostilbene-2,2'-disulfonic acid and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1. The dianhydride is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in a molar ratio of 1:1. The molar ratio of dianhydride to diamine is 1:1. The reactive diluent is N-vinylpyrrolidone, and the initiator is 2-hydroxy-2-methyl-1-phenylpropanone.

[0069] Example 6

[0070] The temporary bonded laser release material of this embodiment contains 20 parts of polyimide with active sites, 78.9 parts of reactive diluent, 1 part of catalyst, and 0.1 parts of silicone leveling agent.

[0071] The active sites of the polyimide are hydroxyl and amino groups. The diamine used in the copolymerization reaction is selected as 9,9-bis(3-hydroxy-4-aminophenyl)fluorene and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1. The dianhydride used is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, and the molar ratio of dianhydride to diamine is 1:1. The active diluent is diphenylmethane diisocyanate, and the catalyst is dibutyltin dilaurate.

[0072] Example 7

[0073] The temporary bonded laser release material of this embodiment contains 20 parts polyimide, 78.4 parts reactive diluent, 1 part catalyst, 0.1 parts silicone leveling agent, and 0.5 parts silane coupling adhesion promoter.

[0074] The active sites of the polyimide are hydroxyl and amino groups. The diamine used in the copolymerization reaction is selected as 9,9-bis(3-hydroxy-4-aminophenyl)fluorene and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1. The dianhydride is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, and the molar ratio of dianhydride to diamine is 1:1. The active diluent is diphenylmethane diisocyanate, and the catalyst is dibutyltin dilaurate.

[0075] Example 8

[0076] The main difference between this embodiment and Example 1 is the mass fraction of polyimide and reactive diluent in the temporary bonded laser-emitting material; the rest is the same as in Example 1. Specifically, the temporary bonded laser-emitting material contains 50 parts of polyimide with active sites, 49 parts of reactive diluent, and 1 part of catalyst.

[0077] Example 9

[0078] The main difference between this embodiment and Embodiment 7 lies in the mass fraction of each component in the temporary bonded laser-emitting material; the rest is the same as in Embodiment 7. Specifically, the temporary bonded laser-emitting material contains 63 parts polyimide, 32 parts reactive diluent, 2.5 parts catalyst, 0.5 parts silicone-based leveling agent, and 2 parts silane coupling adhesion promoter.

[0079] Example 10

[0080] The main difference between this embodiment and Example 1 is the mass fraction of polyimide and reactive diluent in the temporary bonded laser-emitting material; the rest is the same as in Example 1. Specifically, the temporary bonded laser-emitting material contains 75 parts of polyimide with active sites, 24 parts of reactive diluent, and 1 part of catalyst.

[0081] Comparative Example 1

[0082] The temporary bonded laser-emitting material in this comparative example is solvent-containing, comprising 20 parts polyimide and 80 parts solvent NMP.

[0083] In the preparation of polyimide, the diamine used is selected as 9,9-bis(3-hydroxy-4-aminophenyl)fluorene and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1, and the dianhydride is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, with a molar ratio of dianhydride to diamine of 1:1.

[0084] Comparative Example 2

[0085] The temporary bonded laser-emitting material in this comparative example is solvent-containing, comprising 50 parts polyimide and 50 parts solvent DMAc.

[0086] In the preparation of polyimide, the diamine used is selected as 3,3'-diaminobenzidine and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1, and the dianhydride is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, with a molar ratio of dianhydride to diamine of 1:1.

[0087] Comparative Example 3

[0088] The temporary bonded laser-emitting material in this comparative example is solvent-containing, comprising 75 parts polyimide and 25 parts solvent DMF.

[0089] In the preparation of polyimide, the diamine used is selected as 4,4'-diaminostilbene-2,2'-disulfonic acid and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1, and the dianhydride is selected as 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride in a molar ratio of 1:1.

[0090] Performance testing:

[0091] To better understand this invention, the temporary bonded laser-emitting materials of the above embodiments and comparative examples were bonded to a carrier and wafer using other resins as an adhesive layer. Simulating PECVD and reflow soldering processes, an ultrasonic scanning microscope was used to observe whether voids were generated at the laser-emitting layer / carrier interface, or whether separation occurred at the laser-emitting layer / carrier interface. If no voids were generated at the laser-emitting layer / carrier interface, an ultraviolet laser was used for scanning irradiation to see if debonding was possible, and the laser energy corresponding to debonding was statistically analyzed. The specific steps are as follows:

[0092] Step 1: Bonding - The temporary bonding laser release materials of the above embodiments and comparative examples are spin-coated onto a 500-micron UV fused quartz glass substrate at a speed of 1000-3000 rpm for 15-40 seconds using a spin coater to form a laser release layer. Through process control, the dry film thickness of the above embodiments and comparative examples is 1 micron. A commercially available temporary bonding adhesive layer material (Shenzhen Huaxun Semiconductor Materials Co., Ltd., model TB4180) is spin-coated onto the surface of a 500-micron thick wafer at a speed of 500 rpm for 15 seconds using a spin coater. The wafer is then placed on a hot plate and baked at 110°C for 10 minutes, followed by baking at 220°C for 20 minutes to form a 50-micron thick adhesive layer.

[0093] For Examples 1-4 and Examples 6-10, after spin coating, the glass substrate was placed on a hot plate and baked at 180°C for 10 minutes for thermosetting; for Example 5, after spin coating, the glass substrate was placed under a UV LED with a wavelength of 365nm and a power of 300mW / cm². 2Under light, the glass substrate was irradiated for 10 seconds to cure the solvent. For comparative examples 1 to 3, after spin coating, the glass substrate was placed on a hot plate and baked at 180°C for 60 minutes to remove the solvent.

[0094] Align the glass substrate vertically with the wafer, align the laser release layer with the adhesive layer, and apply a 20 kgf / in solution. 2 Under pressure, vacuum hot-press bonding at 180℃ for 5 minutes yields bonded pairs of temporary bonded adhesive.

[0095] Step 2: To investigate the impact of subsequent processes (PECVD, reflow soldering, etc.) on temporary bonding adhesive, the bonded pairs were placed in a simulated environment with a vacuum of 0.01 mbar and a temperature of 260°C for 10 minutes. The laser release layer / carrier interface was observed with an ultrasonic scanning microscope to see if any voids were generated, or the laser release layer / carrier interface was visually inspected to see if separation occurred.

[0096] Step 3: Debonding - Irradiate the bonded pairs from the UV fused quartz glass substrate side using a solid-state UV laser in an S-shaped scanning pattern, starting at 100 mJ / cm². 2 Initially, gradually increase the light intensity to 1000 mJ / cm². 2 We observe whether the bond pairs separate and count the laser energy corresponding to the debonding.

[0097] Step 4: Residual Adhesive Removal: Fix the debonded UV fused silica glass substrate onto a spin coater and rotate it at 1500 rpm. Spray the surface with a temporary bonding adhesive heated to 60°C and a corresponding high-purity solvent for 10 minutes. Then spray the surface with deionized water for 5-10 minutes. Finally, use an X-ray energy dispersive spectroscopy (EDS) instrument to test whether there is nitrogen (N) from polyimide on the surface of the silicon wafer or UV fused silica glass. If not, the residual adhesive has been completely removed.

[0098] Table 1 summarizes and records information such as whether there are voids in the interface, threshold debonding energy, and whether residual glue has been completely removed.

[0099] Table 1

[0100]

[0101] As shown in Table 1, the test results of Examples 1-10 and Comparative Examples 1-3 reveal that, because polyimide structures all contain ether bonds or fluorene groups (rigid groups), residual adhesive can be completely removed by solvent soaking. However, the solvent-containing polyimide temporary bonded laser-emitting materials (Comparative Examples 1-3), after baking at 180°C for 60 minutes, still exhibited voids at the interface with the glass substrate, and even interface separation occurred, proving that the solvent was not completely removed. Conversely, the solvent-free polyimide temporary bonded laser-emitting materials (Examples 1-10), after only 10 minutes of crosslinking thermocuring or a few seconds of photocuring at the same 180°C, did not exhibit voids at the interface with the glass substrate; furthermore, the bonded pairs successfully debonded under ultraviolet laser scanning.

[0102] A comparison of the test results of Examples 1, 3, and 7-10 shows that as the content of polyimide in the temporary bonded laser-emitting material increases, the required UV laser threshold energy for debonding first decreases and then increases. When the content of polyimide in the temporary bonded laser-emitting material is 50-75 parts and the content of reactive diluent is 24-49 parts, the threshold debonding energy is relatively low, below 300 mJ / cm². 2 This can reduce the risk of wafer warping and cracking caused by high-energy lasers and their thermal effects, thereby improving laser lifespan and debonding efficiency.

[0103] Furthermore, comparing the test results of Comparative Examples 1-3 with those of Examples 1 and 10 shows that, within the scope of this invention, appropriately increasing the polyimide content can reduce the required UV laser threshold energy for debonding. In Comparative Example 2, since the laser-emitting layer / carrier interface has already separated, further debonding is unnecessary; while in Comparative Examples 1 and 3, as the content of polyimide in the temporary bonded laser-emitting material increases (within the scope of this invention), the required UV laser threshold energy for debonding decreases; however, compared to the same content of polyimide (Comparative Examples 1 and 3 correspond to Examples 1 and 10, respectively), increasing the reactive diluent can further reduce the required UV laser threshold energy for debonding.

[0104] Therefore, the solvent-free temporary bonded laser release material provided by the present invention can not only achieve the functions of debonding and removing residual adhesive, but also eliminate the risk of voids forming at the interface of the laser release layer with the carrier substrate due to the evaporation of residual solvent, which affects wafer processing and may even lead to interface separation failure, thereby improving the reliability of wafer processing.

[0105] 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 temporary bonded laser-emitting material, characterized in that, The temporary bonded laser-emitting material comprises a polyimide containing active sites, a reactive diluent with crosslinkable groups, and an initiator or catalyst; the polyimide is dissolved in the reactive diluent, and the initiator or catalyst is used to initiate a crosslinking reaction between the reactive diluent and the polyimide.

2. The temporary bonded laser-emitting material according to claim 1, characterized in that, The active sites in the polyimide include at least one of hydroxyl, amino, and carbon-carbon double bonds.

3. The temporary bonded laser-emitting material according to claim 2, characterized in that, The crosslinkable groups in the reactive diluent include at least one of epoxy, acrylate, vinyl, and isocyanate groups.

4. The temporary bonded laser-emitting material according to claim 3, characterized in that, The active sites in the polyimide are hydroxyl and / or amino groups, and the crosslinkable groups in the reactive diluent are epoxy and / or isocyanate groups; and / or, The active site in the polyimide is a carbon-carbon double bond, and the crosslinkable group in the reactive diluent is an acrylate group and / or a vinyl group.

5. The temporary bonded laser-emitting material according to claim 3, characterized in that, When the crosslinkable groups in the reactive diluent are epoxy-based, the initiator includes a cationic initiator selected from at least one of boron trifluoride-ethylamine complex, diaryliodonium hexafluorophosphate, and triarylthionium hexafluorophosphate; and / or, When the crosslinkable groups in the reactive diluent are acrylates and / or vinyl groups, the initiator is a free radical initiator, which is a thermal initiator or a photoinitiator. The thermal initiator is benzoyl peroxide or di-tert-butyl peroxide; the photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone or 1-hydroxycyclohexylphenyl ketone; and / or... When the crosslinkable group in the active diluent is an isocyanate group, the catalyst is an organotin catalyst.

6. The temporary bonded laser-emitting material according to claim 1, characterized in that, The main chain of the polyimide contains ether bonds or rigid groups, and the rigid groups include at least one of fluorenyl or indene structures.

7. The temporary bonded laser-emitting material according to claim 1, characterized in that, The temporary bonded laser release material also includes additives, which are leveling agents and / or adhesion promoters.

8. The temporary bonded laser-emitting material according to claim 7, characterized in that, The temporary bonded laser-emitting material comprises, by weight, 20-79 parts of polyimide, 20-79 parts of reactive diluent, 0.1-5.0 parts of initiator or catalyst, and 0-2.5 parts of additives.

9. The temporary bonded laser-emitting material according to claim 8, characterized in that, The leveling agent is an organosilicon or fluorocarbon leveling agent, and the amount of the leveling agent added is 0 to 0.5 parts of the total amount of the temporary bonded laser-emitting material; and / or The adhesion promoter is a silane coupling agent, and the amount of the adhesion promoter added is 0 to 2.0 parts of the total amount of the temporary bonded laser release material.

10. An application of the temporary bonded laser-emitting material as described in any one of claims 1 to 9, characterized in that, The temporary bonding laser release material is used in wafer processing to temporarily bond the wafer to the carrier.

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