Temporary bonding adhesive and its use

Abstract

The application discloses a kind of temporary bonding glue and its application.Temporary bonding glue includes polyimide, the polyimide includes big conjugate unit, the conjugate atom number of big conjugate unit is greater than or equal to 40, and big conjugate unit includes at least one of diphenyl ether group, fluorenyl group or indane structural unit;The polyimide further includes at least one of benzotriazole group, nitro group.The application is improved on the structure of polyimide, and the temporary bonding glue is used in wafer processing, so that the absorbance of temporary bonding glue at target debonding wavelength 355nm is significantly increased, thereby significantly reducing threshold debonding energy, and it is expected to reduce the risk of wafer warping, cracking, or surface device failure, improve the life of laser and debonding efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of wafer processing materials, specifically relating to a temporary bonding adhesive and its application. Background Technology

[0002] With the rapid development of the semiconductor industry, integrated circuit chips are constantly evolving towards miniaturization, multifunctionality, and intelligence. Advanced packaging technology, as a key driving force behind this trend, is gradually becoming a core direction for industry development. In advanced 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.

[0003] In wafer fabrication, to meet the heat dissipation and packaging requirements of chips, wafers often need to be thinned to a specific thickness. However, ultra-thin 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 technology 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 for the ultra-thin wafer and ensuring its smooth operation 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 ultra-thin device wafer.

[0004] Among various debonding methods, ultraviolet laser debonding has significant advantages in large-size ultrathin wafer processing due to its high efficiency, room temperature operation, and low stress, making it a research hotspot and development trend in the field of temporary bonding technology. Polyimide materials, with their excellent thermal stability, chemical stability, mechanical properties, good film-forming properties, and good ultraviolet absorption capacity, are ideal temporary bonding adhesive materials for ultraviolet laser debonding.

[0005] However, existing polyimide temporary bonding adhesives have low UV absorbance and threshold debonding energy exceeding 400 mJ / cm². 2 High-energy lasers and their thermal effects can cause wafer warping, cracking, or failure of surface devices (such as metal wiring and dielectric layers), while also reducing laser lifespan. Furthermore, high-energy lasers require a low scanning speed to avoid excessively high local energy, resulting in lower debonding efficiency. Summary of the Invention

[0006] To address the problem of low debonding efficiency in existing polyimide temporary bonding adhesives, this invention provides a temporary bonding adhesive and its application to improve debonding efficiency.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] In a first aspect, the present invention provides a temporary bonding adhesive comprising a polyimide, wherein the polyimide comprises a large conjugated unit, the large conjugated unit having ≥40 conjugated atoms, and the large conjugated unit comprising at least one of a diphenyl ether group, a fluorenyl group, or an indane structural unit; the polyimide further comprises at least one of a benzotriazole group or a nitro group.

[0009] Furthermore, the polyimide is continuously conjugated.

[0010] Furthermore, the polyimide is obtained by reacting a raw material composition comprising a diamine and a dianhydride, wherein the diamine contains at least one of a nitro group and a benzotriazole group.

[0011] Furthermore, the molar ratio of the diamine to the dianhydride is (0.95~1.05):1.

[0012] Furthermore, the temporary bonding adhesive has an absorption coefficient ≥1.6 L / (g·cm) at a wavelength of 355 nm; the preferred absorption coefficient is 1.707~2.671 L / (g·cm).

[0013] Furthermore, when the carrier is a 490-510 micrometer thick ultraviolet fused quartz glass, the threshold debonding energy of the temporary bonding adhesive under a 355nm ultraviolet laser is <300mJ / cm². 2 Preferably, when the carrier is a 490-510 micrometer thick ultraviolet fused quartz glass, the threshold debonding energy of the temporary bonding adhesive under a 355nm ultraviolet laser is 100-230 mJ / cm². 2 .

[0014] Furthermore, the mass fraction of the polyimide in the temporary bonding adhesive is 10~40wt%.

[0015] Furthermore, the temporary bonding adhesive also includes a leveling agent, which is an organosilicon or fluorocarbon leveling agent, and the mass fraction of the leveling agent is 0.1~1wt%.

[0016] In a second aspect, the present invention provides an application of the temporary bonding adhesive as described in the first aspect, wherein the temporary bonding adhesive is used in wafer processing to temporarily bond the wafer to a carrier.

[0017] Compared with the prior art, the present invention has the following beneficial effects.

[0018] The polyimide of this invention has large conjugated units with ≥40 conjugated atoms, which can significantly enhance the absorbance in the UV region of 200-400 nm. The benzotriazole group can enhance the absorbance in the 300-380 nm band, and the nitro group can red-shift the absorption peak, thereby enhancing the absorbance at the target debonding wavelength of 355 nm. Through the improvement of the polyimide structure, the absorption coefficient of the temporary bonding adhesive at the target debonding wavelength of 355 nm is significantly increased, with an absorption coefficient ≥1.6 L / (g·cm), thereby significantly reducing the threshold debonding energy.

[0019] The temporary bonding adhesive of this invention has a threshold debonding energy of less than 300 mJ / cm. 2 Even better, below 230mJ / cm 2 Even up to 150 mJ / cm 2 The following technologies have significant effects and are expected to reduce the risk of wafer warping, cracking, or failure of surface devices (such as metal wiring and dielectric layers), improve laser lifespan, and significantly improve debonding efficiency. Detailed Implementation

[0020] 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.

[0021] In a first aspect, the present invention provides a temporary bonding adhesive comprising a polyimide, wherein the polyimide comprises a large conjugated unit, the number of conjugated atoms of the large conjugated unit being ≥40, and the large conjugated unit comprising at least one of a diphenyl ether group, a fluorenyl group, or an indane structure; the polyimide further comprises at least one of a benzotriazole group or a nitro group.

[0022] The large conjugated unit is at least one of diphenyl ether, fluorene, or indene structures. This not only significantly enhances the absorbance in the UV region (200-400 nm), but the introduction of the diphenyl ether, fluorene, or indene sterically hindered structure also improves the solubility of the temporary bonded adhesive, thereby improving the washability of the residue after debonding. While large conjugated units such as biphenyl can enhance UV absorption, they reduce the solubility of the temporary bonded adhesive, which is detrimental to the washability of the residue after debonding; therefore, it is necessary to introduce diphenyl ether, fluorene, or indene structures into the polyimide structure.

[0023] In this invention, the number of conjugated atoms refers to the number of atoms that participate in the conjugation process in the conjugated system.

[0024] In some specific embodiments, the polyimide is continuously conjugated. Continuous conjugation refers to the interconnection of multiple conjugated systems to form a larger conjugated system. This results in higher absorbance and lower threshold debonding energy for the temporary bonded adhesive at 355 nm.

[0025] In some specific embodiments, the main chain of the polyimide includes large conjugated units, and the side chains include at least one of benzotriazole groups and nitro groups, wherein the main chain of the polyimide is continuously conjugated.

[0026] In some specific embodiments, the polyimide is obtained by reacting a raw material composition comprising a diamine and a dianhydride, wherein the diamine contains at least one of a nitro group and a benzotriazole group.

[0027] In some specific embodiments, the molar ratio of the diamine to the dianhydride is (0.95~1.05):1.

[0028] In some specific embodiments, the mass fraction of polyimide in the temporary bonding adhesive is 10~40wt%.

[0029] In some specific embodiments, the temporary bonding adhesive has an absorption coefficient ≥1.6 L / (g·cm) at a wavelength of 355nm; specifically, the absorption coefficient can be 1.60L / (g·cm), 1.707L / (g·cm), 1.85L / (g·cm), 2.00L / (g·cm), 2.15L / (g·cm), 2.30L / (g·cm), 2.45L / (g·cm), 2.60L / (g·cm), 2.671L / (g·cm), 2.75L / (g·cm), 2.90L / (g·cm), etc.; preferably 1.707~2.671L / (g·cm).

[0030] In some specific embodiments, when the carrier is a 490-510 micrometer thick ultraviolet fused quartz glass, the threshold debonding energy of the temporary bonding adhesive under a 355nm ultraviolet laser is <300mJ / cm². 2 Specifically, the threshold debonding energy can be 295 mJ / cm². 2 260mJ / cm 2 220mJ / cm 2 170mJ / cm 2 120mJ / cm 2 100mJ / cm 2 90mJ / cm 2 or 80mJ / cm 2 , etc.; preferably 100~230mJ / cm 2 .

[0031] In some specific embodiments, the solvent in the temporary bonding adhesive is at least one selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and cyclohexanone.

[0032] In some specific embodiments, the temporary bonding adhesive further includes a leveling agent, which is an organosilicon or fluorocarbon leveling agent, and the mass fraction of the leveling agent is 0.1~1wt%. The main purpose of the leveling agent is to improve the thickness uniformity of the temporary bonding adhesive after spin coating on the wafer.

[0033] Specifically, silicone-based leveling agents can be selected from polydimethylsiloxane, polymethylalkylsiloxane, and organically modified polysiloxane; fluorocarbon-based leveling agents mainly consist of fluorinated modified polyacrylate or perfluorocarbon copolymers. The mass fraction of the leveling agent can be 0.1wt%, 0.2wt%, 0.35wt%, 0.5wt%, 0.63wt%, 0.71wt%, 0.82wt%, 0.9wt%, or 1wt%, etc.

[0034] The preparation method of the temporary bonding adhesive can be known to those skilled in the art or can be known to those skilled in the art based on the prior art. For example, a polyimide precursor polyamic acid can be obtained by copolymerizing diamine and dianhydride, and the polyamic acid can be thermally imidized to obtain polyimide. Then, a solvent (and a leveling agent) can be added to obtain a temporary bonding adhesive for bonding wafers and substrates; or the polyamic acid obtained by copolymerization can be dissolved in the above solvent and directly used for bonding wafers and substrates, followed by thermal imidization.

[0035] To enhance UV absorption and improve the debonding efficiency of temporary bonded adhesives, the diamine used in this invention is preferably a diamine containing a nitro group and / or a phenyltriazole group. Simultaneously, to improve the solubility of the temporary bonded adhesive and thus enhance the washability of the residue after debonding, the diamine used in this invention can also be combined with diamines containing diphenyl ether, fluorenyl, or indane structures; the dianhydride used can be a dianhydride containing diphenyl ether, fluorenyl, or indane structures.

[0036] Specifically, the diamine used in this invention is preferably at least one selected from 3,3'-dinitrobenzidine, 4,4'-diaminodiphenyl ether, 2-nitro-p-phenylenediamine, 9,9-bis(4-aminophenyl)fluorene, and 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid. When 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid is selected as the diamine, a benzotriazole group can be introduced by esterification with a compound containing hydroxyl and benzotriazole groups, such as 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, followed by subsequent copolymerization with a dianhydride, thereby resulting in a polyimide with benzotriazole groups on its side chains. The dianhydride used in this invention preferably includes at least one selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride and 2,3,3',4'-biphenyltetracarboxylic dianhydride. Thus, after the copolymerization reaction of diamine and dianhydride, the resulting polyimide has at least one of benzotriazole group and nitro group on its side chain.

[0037] In a second aspect, the present invention provides an application of the temporary bonding adhesive as described in the first aspect, wherein the temporary bonding adhesive is used in wafer processing to temporarily bond the wafer to a carrier.

[0038] Bonding with temporary bonding adhesive: The temporary bonding adhesive is spin-coated onto one side of a 420-micron thick silicon wafer using a spin coater at 1500-3000 rpm for 15-40 seconds. The silicon wafer is then baked at 80-120℃ for 10-30 minutes to remove the solvent, forming a uniform adhesive film on the wafer. Next, a UV-cured fused silica glass substrate of the same size and 490-510 microns thick is placed over the adhesive film on the silicon wafer. After alignment, the substrate is bonded at 10-30 kgf / in... 2 Under pressure and at a temperature of 150~180℃, the silicon wafer and the carrier are vacuum hot-pressed to form a bonding pair; then, under a nitrogen atmosphere, it is treated at 250~350℃ for 0.5~4 hours.

[0039] Debonding of temporary bonded adhesive: The bonded pairs were irradiated from the molten quartz glass side using a solid-state ultraviolet laser in an S-shaped scanning pattern, at a concentration of 100 mJ / cm². 2 Initially, the light intensity is gradually increased until the silicon wafer and the ultraviolet quartz molten glass just separate.

[0040] The specific embodiments of the present invention will be further explained and described below through examples and comparative examples.

[0041] 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.

[0042] Example 1

[0043] The temporary bonding adhesive of this embodiment contains 15 wt% polyimide and N,N-dimethylacetamide as solvents.

[0044] The diamine used in the copolymerization reaction was selected from 3,3'-dinitrobenzidine and 4,4'-diaminodiphenyl ether in a molar ratio of 1:1, and the dianhydride was selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride. The selected diamine and dianhydride were copolymerized at 30°C for 14 hours to obtain polyamic acid. Polyimide was then obtained by thermal imidization at 300°C for 8 hours. N,N-dimethylacetamide was added to adjust the mass fraction of the polyimide to 15 wt%, thus obtaining a temporary bonding adhesive for bonding wafers and substrates. The polyimide backbone in the prepared temporary bonding adhesive is continuously conjugated, and each repeating unit contains two nitro groups.

[0045] Example 2

[0046] The temporary bonding adhesive of this embodiment contains 10 wt% polyimide and N,N-dimethylacetamide as solvents.

[0047] The diamine used in the copolymerization reaction was selected from 2-nitro-p-phenylenediamine and 9,9-bis(4-aminophenyl)fluorene in a molar ratio of 1:1, and the dianhydride was selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride and 2,3,3',4'-biphenyl tetracarboxylic dianhydride in a molar ratio of 1:1. A temporary bonded adhesive was prepared according to the method in Example 1. The main chain of the polyimide in the temporary bonded adhesive has large conjugated units with ≥55 conjugated atoms, and each repeating unit contains one nitro group.

[0048] Example 3

[0049] The temporary bonding adhesive of this embodiment contains 15 wt% polyimide and N,N-dimethylacetamide as solvents.

[0050] The diamine used in the copolymerization reaction was selected from 2-nitro-p-phenylenediamine, and the dianhydride was selected from 2,3,3',4'-biphenyltetracarboxylic dianhydride, with a molar ratio of 1:1 between the selected diamine and dianhydride. A temporary bonded adhesive was prepared according to the method in Example 1. The polyimide backbone in the temporary bonded adhesive is continuously conjugated, and each repeating unit contains one nitro group.

[0051] Example 4

[0052] The temporary bonding adhesive of this embodiment contains 20 wt% polyimide and N,N-dimethylacetamide as solvents.

[0053] The diamine used in the copolymerization reaction was selected from 9,9-bis(4-aminophenyl)fluorene and 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid in a molar ratio of 1:1. The 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid was first esterified with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole to introduce benzotriazole groups. The dianhydride used was selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride. The selected diamine and dianhydride were copolymerized at 30°C for 14 hours to obtain polyamic acid. Then, polyimide was obtained by thermal imidization at 300°C for 8 hours. Finally, N,N-dimethylacetamide was added to adjust the mass fraction of the polyimide to 20 wt%, thus obtaining the temporary bonded adhesive. The main chain of the polyimide in the temporary bonded adhesive has large conjugated units with ≥40 atoms, and each repeating unit contains two benzotriazole groups.

[0054] Example 5

[0055] The temporary bonding adhesive of this embodiment contains 0.5 wt% silicone leveling agent, 15 wt% polyimide, and N-methylpyrrolidone as solvents.

[0056] The diamine used in the copolymerization reaction was selected from 9,9-bis(4-aminophenyl)fluorene and 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid in a molar ratio of 1:1. The 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid was first esterified with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole to introduce benzotriazole groups. The dianhydride used was selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride. The selected diamine and dianhydride were mixed in a molar ratio of 1:1, and polyimide was prepared according to the method in Example 4. Finally, N-methylpyrrolidone and 0.5 wt% silicone leveling agent were added, and the mass fraction of the polyimide was adjusted to 15 wt% to obtain the temporary bonded adhesive. The main chain of the polyimide in the temporary bonded adhesive has large conjugated units with ≥40 atoms, and each repeating unit contains two benzotriazole groups.

[0057] Example 6

[0058] The temporary bonding adhesive of this embodiment contains 0.8 wt% fluorocarbon leveling agent, 40 wt% polyimide, and cyclohexanone as solvents.

[0059] The diamine used in the copolymerization reaction was selected from 2-nitro-p-phenylenediamine, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, and 9,9-bis(4-aminophenyl)fluorene in a molar ratio of 1:1:1. The 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid was first esterified with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole to introduce a benzotriazole group. The dianhydride used was selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride. The selected diamine and dianhydride were in a molar ratio of 1:1, and polyimide was prepared according to the method in Example 4. Finally, cyclohexanone and 0.8 wt% fluorocarbon leveling agent were added, and the mass fraction of the polyimide was adjusted to 40 wt% to obtain the temporary bonded adhesive. The main chain of the polyimide in the temporary bonded adhesive has large conjugated units with ≥40 atoms, and each repeating unit contains one nitro group and two benzotriazole groups.

[0060] Comparative Example 1

[0061] The temporary bonding adhesive of this comparative example contains 15 wt% polyimide and N,N-dimethylacetamide as solvents; the diamine used in the copolymerization reaction is selected from 2-nitro-p-phenylenediamine, and the dianhydride is selected from hexafluorodianhydride, with a molar ratio of 1:1 between the selected diamine and dianhydride. The number of conjugated atoms in the main chain conjugated unit of the polyimide in the temporary bonding adhesive is ≤17, and each repeating unit contains one nitro group.

[0062] Comparative Example 2

[0063] The temporary bonding adhesive of this comparative example contains 15 wt% polyimide and N,N-dimethylacetamide as solvents. The diamine used in the copolymerization reaction is selected from p-phenylenediamine and 9,9-bis(4-aminophenyl)fluorene in a 1:1 molar ratio, and the dianhydride is selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride and 2,3,3',4'-biphenyl tetracarboxylic dianhydride in a 1:1 molar ratio. The selected diamine and dianhydride have a 1:1 molar ratio. The main chain of the polyimide in the temporary bonding adhesive has large conjugated units with ≥55 atoms, but the side chains do not contain benzotriazole groups or nitro groups.

[0064] Comparative Example 3

[0065] The temporary bonding adhesive of this comparative example contains 15 wt% polyimide and N,N-dimethylacetamide as solvents; the diamine used in the copolymerization reaction is selected from p-phenylenediamine, and the dianhydride is selected from hexafluorodianhydride, with a molar ratio of 1:1 between the selected diamine and dianhydride. The number of conjugated atoms in the main chain conjugated unit of the polyimide in the temporary bonding adhesive is ≤17.

[0066] Performance testing:

[0067] To better understand the present invention, the temporary bonding adhesives prepared in the above embodiments and comparative examples were subjected to the following tests, and the test results are shown in Table 1.

[0068] [Absorption Coefficient] The temporary bonded adhesive sample was diluted with the corresponding solvent to a polyimide mass concentration of 0.5 g / L. The absorbance at a wavelength of 355 nm was measured using a UV absorption spectrometer and a cuvette with a 1 cm optical path. The absorption coefficient was then calculated, with the unit being L / (g·cm).

[0069] [Uniformity of film thickness after spin coating] The temporary bonding adhesive sample was spin-coated onto one side of a 420-micron thick silicon wafer at 2000 rpm for 30 seconds using a spin coater. The silicon wafer was then baked at 100℃ for 20 minutes to remove the solvent, and the uniformity of the film thickness after spin coating was tested.

[0070] Threshold Debonding Energy Test

[0071] Bonding: A UV-cured fused silica glass substrate of the same size and 500 micrometers thick is placed over the adhesive film formed on the silicon wafer. After alignment, it is bonded at 20 kgf / in 2 Under pressure and at a temperature of 160°C, the silicon wafer and the carrier are bonded together by vacuum hot pressing; then, under a nitrogen atmosphere, the wafer is treated at 300°C for 2 hours.

[0072] Debonding: The bonded pairs were irradiated from the molten quartz glass side using a solid-state ultraviolet laser in an S-shaped scanning pattern, starting from 100 mJ / cm². 2 Initially, the light intensity is gradually increased until the silicon wafer and the ultraviolet quartz molten glass just separate. The light intensity at this point is recorded, which is the threshold debonding energy.

[0073] [Residual Adhesive Cleaning]: Fix the debonded silicon wafer and UV fused quartz glass on a spin coater and rotate at 2000 rpm. First, heat the high-purity solvent corresponding to the temporary bonding adhesive to 65°C and spray it onto the rotating silicon wafer and UV fused quartz glass surface for 8 minutes. Then, spray the surface with deionized water for 8 minutes. Finally, use an X-ray energy dispersive spectroscopy instrument to test whether there is nitrogen element in polyimide on the surface of the silicon wafer or UV fused quartz glass. If not, the residual adhesive is cleaned.

[0074] Table 1 Test Results

[0075]

[0076] As shown in Table 1, the test results of Examples 1-6 and Comparative Examples 1-3 indicate that the more conjugated atoms in the main chain of polyimide in the temporary bonded adhesive, and even if they are continuously conjugated, the higher the absorption coefficient at 355 nm wavelength and the lower the threshold debonding energy. If the number of conjugated atoms in the main chain of polyimide is small, and / or the side chains do not contain benzotriazole groups and / or nitro groups, the ultraviolet absorption coefficient of the temporary bonded adhesive will be low, and the threshold debonding energy will be significantly high, even exceeding 400 mJ / cm². 2 When the side chain of polyimide contains at least one of benzotriazole group and nitro group, and the number of conjugated atoms of the large conjugated unit of the main chain is ≥40, the threshold debonding energy is low.

[0077] As can be seen from the test results of Example 3, Comparative Examples 1 and 3 and other examples and comparative examples, the polyimide main chain contains diphenyl ether groups, fluorenyl groups or indane structures, which can effectively improve the washability of the residual adhesive after the temporary bonded adhesive is debonded.

[0078] The test results of Examples 5 and 6, along with those of other examples and comparative examples, show that introducing a leveling agent into the temporary bonding adhesive can significantly improve the uniformity of the adhesive film thickness after spin coating.

[0079] Furthermore, the temporary bonding adhesive of this invention has a threshold debonding energy of less than 300 mJ / cm. 2 Even better, below 230mJ / cm 2 Even up to 150 mJ / cm 2 The following technologies have significant effects and are expected to reduce the risk of wafer warping, cracking, or failure of surface devices (such as metal wiring and dielectric layers), improve laser lifespan, and increase debonding efficiency.

[0080] 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 bonding adhesive, characterized in that, The invention includes a polyimide comprising a large conjugated unit having ≥40 conjugated atoms. The polyimide is obtained by reacting a raw material composition comprising a diamine and a dianhydride. The diamine is selected from a combination of 9,9-bis(4-aminophenyl)fluorene and 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, or a combination of 2-nitro-p-phenylenediamine, 9,9-bis(4-aminophenyl)fluorene and 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid. The product obtained by esterifying 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid with 2-(2'-hydroxy-5'-methylphenyl)benzotriazole then participates in the dianhydride reaction. The dianhydride is selected from 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride.

2. The temporary bonding adhesive according to claim 1, characterized in that, The molar ratio of the diamine to the dianhydride is (0.95~1.05):

1.

3. The temporary bonding adhesive according to claim 1, characterized in that, The temporary bonding adhesive has an absorption coefficient of ≥1.6 L / (g·cm) at a wavelength of 355 nm.

4. The temporary bonding adhesive according to claim 3, characterized in that, The temporary bonding adhesive has an absorption coefficient of 1.707~2.671 L / (g·cm) at a wavelength of 355 nm.

5. The temporary bonding adhesive according to claim 4, characterized in that, When the carrier is a 490-510 micrometer thick ultraviolet fused quartz glass, the threshold debonding energy of the temporary bonding adhesive under a 355nm ultraviolet laser is <300mJ / cm. 2 .

6. The temporary bonding adhesive according to claim 1, characterized in that, The mass fraction of polyimide in the temporary bonding adhesive is 10~40wt%.

7. The temporary bonding adhesive according to claim 1, characterized in that, The temporary bonding adhesive also includes a leveling agent, which is an organosilicon or fluorocarbon leveling agent, and the mass fraction of the leveling agent is 0.1~1wt%.

8. The application of a temporary bonding adhesive as described in any one of claims 1 to 7, characterized in that, The temporary bonding adhesive is used in wafer processing to temporarily bond the wafer to the carrier.

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