Linear polyimide, temporary bonding glue containing linear polyimide and application

Abstract

The invention discloses linear polyimide, temporary bonding glue containing the linear polyimide and application of the temporary bonding glue. The linear polyimide has a structure as shown in a formula A, and x: y: z = (1-9): (1-9): (0-9); the weight-average molecular weight of the linear polyimide is 5,000 to 100,000; the first monomer is selected from at least one of tetracarboxylic dianhydride; the second monomer is selected from at least one of aromatic diamines; the third monomer is selected from at least one of polyethylene glycol diamine or polyether diamine. By adding linear polyimide, the temporary bonding adhesive provided by the invention has excellent bonding capacity and ultraviolet absorption capacity, is high in high-temperature resistance and easy to clean, and can be widely applied to the field of semiconductor packaging. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging, and particularly to a linear polyimide, a temporary bonding adhesive containing the same, and applications thereof. Background Art

[0002] With the upgrading of consumer electronic products, high-end chips such as 5G communication, CPU / GPU are also developing towards high frequency and high speed, multi-function, high performance, small size and high reliability. In order to meet the requirements of miniaturization, multi-functionality and intelligence of integrated circuit chips, and at the same time help to solve the physical limit challenges faced by the development of Moore's Law, the development of advanced packaging technologies mainly focuses on three-dimensional packaging, such as chip stacking packaging, package stacking, multi-chip packaging, system-level packaging, wafer-level packaging, fan-out packaging, etc. While reducing the packaging volume, it improves circuit performance, reduces parasitic effects and time delay.

[0003] Among them, fan-out packaging has received extensive attention because it can achieve further high integration, thinness and miniaturization of semiconductor packaging. The key to achieving miniaturization lies in thinning the substrate thickness of the assembled components. In semiconductor processes, wafer thinning is usually carried out after the circuit is laid out, before subsequent dicing, wire bonding and packaging. The purpose is to reduce the chip packaging volume, improve the thermal diffusion efficiency, electrical performance and mechanical performance of the chip, and reduce the processing amount of dicing. When the wafer is thinned to a certain thickness or less, some problems will be encountered in terms of fixation and equipment operation, making further thinning difficult. Therefore, it is necessary to mount or fix the wafer to a rigid carrier and thin the substrate, but its strength will be reduced, and it is easy to break during the manufacture of semiconductor devices.

[0004] In view of the above situation, a temporary bonding adhesive is needed to bond the substrate to the support. The temporary bonding adhesive is a special polymer material acting between the device wafer and the carrier wafer, which plays a role of support and bonding until the device wafer completes processes such as thinning, polishing and stacking.

[0005] The temporary bonding material needs to meet the following requirements: having sufficient bonding force to support the RDL process of ultra-thin chips in WLP and high-density fan-out packaging; having good thermal stability to meet processes such as reflow soldering; having sufficient ultraviolet absorption performance to achieve efficient debonding; having excellent solubility to meet the cleaning process of the wafer surface after debonding.

[0006] However, on the one hand, the existing temporary bonding adhesives usually have a tolerance temperature below 300°C and cannot withstand high-temperature CVD or similar high-temperature vacuum processes, so their application scope is limited. On the other hand, the existing temporary bonding adhesives on the market usually use two functional colloids in combination, namely an adhesive layer and a photosensitive layer. The adhesive layer plays a role in bonding and supporting, and the photosensitive layer plays a role in laser ablation and debonding. Its cost is high and the process is complex. Moreover, the thermal decomposition bonding adhesives used in the semiconductor packaging section in the prior art usually have problems such as unclean cleaning and difficult removal of residual glue.

[0007] Therefore, there is an urgent need for a temporary bonding adhesive with strong high-temperature resistance, easy cleaning, and at the same time having bonding ability and ultraviolet absorption ability. Summary of the Invention

[0008] Object of the Invention: Aiming at the defects of the prior art, the object of the present invention is to provide a linear polyimide and a temporary bonding adhesive containing the same, which has strong high-temperature resistance, easy cleaning, and at the same time has bonding ability and ultraviolet absorption ability, and its application.

[0009] Technical Solution:

[0010] On the one hand, the present invention provides a linear polyimide having a structure shown in Formula A below:

[0011]

[0012] Wherein, x:y:z = (1-9):(1-9):(0-9);

[0013] The weight-average molecular weight of the linear polyimide is 5000-100000;

[0014] The first monomer is selected from at least one of tetracarboxylic dianhydrides;

[0015] The second monomer is selected from at least one of aromatic diamines;

[0016] The third monomer is selected from at least one of polyethylene glycol diamine or polyether diamine.

[0017] For example, the weight-average molecular weight of the linear polyimide can be 5000, 10000, 15000, 20000, 25000, 30000, 35000, 40000, 45000, 50000, 55000, 60000, 65000, 70000, 75000, 80000, 75000, 80000, 85000, 90000, 95000, 100000.

[0018] In some embodiments of the present invention, the weight-average molecular weight of the linear polyimide is 60000-90000.

[0019] The tetracarboxylic dianhydride is selected from one of 3,3',4,4'-diphenylether tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5-(2,5-dioxotetrahydrofuran)-3-methyl-3-cyclohexene-1,2-dicarbonic anhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,3,3',4'-diphenylether tetracarboxylic dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, pyromellitic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)sulfide dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, bicyclo[2.2.1]heptane-2,3,5,6-tetracarboxylic dianhydride, and bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride.

[0020] The aromatic diamine is selected from one of 9,9-bis(4-aminophenyl)fluorene, 4,4'-methylenedi(2,6-diethylaniline), 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(1,3-phenylenediisopropylidene)diphenylamine, 4-aminophenyl sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, o-dianisidine, 1,5-diaminonaphthalene, m-xylenediamine, p-xylenediamine, 4,4'-diaminodiphenyl ether, bis(3-aminophenyl) sulfone, 1,3-benzenediamine, 4,4'-diaminodiphenylmethane, 4,4'-methylenedi(2-chloroaniline), α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, 1,4-benzenediamine, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(trifluoromethyl)benzidine, 2,7-diaminofluorene, 3,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethylbenzidine, 9,9-bis(4-amino-3-methylphenyl)fluorene, bis(3-amino-4-hydroxyphenyl) sulfone, 3-aminobenzylamine, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4'-bis(4-aminophenoxy)biphenyl, 1,1-bis(4-aminophenyl)cyclohexane, 3,4'-diaminodiphenyl ether, 4,4'-ethylidenebenzidine, 2,3,5,6-tetramethyl-1,4-benzenediamine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4'-methylenedi(2-ethyl-6-methylaniline), m-toluidine, bis(4-aminophenyl) sulfide, o-toluidine, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 9,9-bis(4-amino-3-fluorophenyl)fluorene, 9,9-bis(4-amino-3-chlorophenyl)fluorene, or 4,4'-diamino-2,2'-dimethylbibenzyl.

[0021] The linear polyimide of the present invention contains three types of monomers. By polymerizing the first monomer tetracarboxylic dianhydride with the second monomer aromatic diamine and the third monomer polyethylene glycol diamine or polyether diamine, the prepared linear polyimide can simultaneously have adhesive ability and ultraviolet light absorption ability, and has excellent high temperature resistance.

[0022] Among them, aromatic diamines can endow polyimide with rigidity, photosensitivity and heat resistance, so that the obtained polyimide has ultraviolet light absorption ability and can be debonded under ultraviolet light; polyethylene glycol diamine or polyether diamine can improve the rheology and solubility of polyimide and endow polyimide with certain bonding ability.

[0023] In some embodiments of the present invention, the first monomer is selected from at least one of 3,3',4,4'-diphenylether tetracarboxylic dianhydride, 2,3,3',4'-diphenylether tetracarboxylic dianhydride, pyromellitic dianhydride or 1,2,4,5-cyclohexane tetracarboxylic dianhydride;

[0024] In some embodiments of the present invention, the second monomer is selected from at least one of 1,4-phenylenediamine, 4,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)benzene, 4,4'-diamino-3,3'-dimethyl diphenylmethane or 3,3'-diaminodiphenylmethane;

[0025] The third monomer is selected from at least one of polyethylene glycol diamine with a molecular weight of 400-10000 or polyether diamine with a molecular weight of 200-5000.

[0026] In some embodiments of the present invention, the structural formula of the polyethylene glycol diamine is with a molecular weight of 400-10000; the structural formula of the polyether diamine is with a molecular weight of 200-5000.

[0027] For example, the molecular weight of the polyethylene glycol diamine can be 400, 800, 1200, 1600, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000.

[0028] In some embodiments of the present invention, the molecular weight of the polyethylene glycol diamine is 800-8000.

[0029] In some embodiments of the present invention, the molecular weight of the polyethylene glycol diamine is 1200-6000.

[0030] In some embodiments of the present invention, the molecular weight of the polyether diamine can be 200, 230, 400, 600, 800, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000.

[0031] In some embodiments of the present invention, the molecular weight of the polyether diamine is 400-3000.

[0032] In some embodiments of the present invention, the polyether diamine has a molecular weight of 800 - 2000. The first monomer and the second monomer selected in the present invention can further improve the ultraviolet light absorption ability and high-temperature resistance of the linear polyimide; and by using a polyethylene glycol diamine with a molecular weight of 400 - 10000 or a polyether diamine with a molecular weight of 200 - 5000 as the third monomer, the flexibility, fluidity, and adhesiveness of the polyimide can be further improved.

[0033] Through the selection and combined use of three types of monomers in the present invention, the rigid structure and the flexible structure between the monomers cooperate with each other, so that the prepared linear polyimide can simultaneously have excellent mechanical properties, heat resistance, adhesiveness, and ultraviolet light absorption ability.

[0034] In some embodiments of the present invention, the third monomer is selected from polyether diamines with a molecular weight of 200 - 5000.

[0035] In the linear polyimide of the present invention, polyether diamine is selected as the third monomer, which has better solubility, rheology, and adhesiveness compared with polyethylene glycol diamine, and can further improve the bonding ability and heat resistance of the linear polyimide.

[0036] In some embodiments of the present invention, the decomposition temperature Td of the linear polyimide > 580 °C, and the ultraviolet light absorption rate at 355 nm > 98%.

[0037] On the other hand, the present invention provides a method for preparing the above linear polyimide, comprising the following steps:

[0038] (1) In a reactor, add the first monomer and the second monomer and copolymerize until the reaction is complete;

[0039] (2) Add the third monomer to the reactor in step (1) and copolymerize until the reaction is complete to obtain the linear polyimide;

[0040] Generally, the reaction to form polyimide is a random reaction between amine monomers and anhydride monomers to form the imine bond and repeating structure of polyimide. When three types of monomers are added to the reactor at the same time, the structure of the polymer chain after their random reaction is It is difficult to exhibit good mechanical properties and ultraviolet absorption ability.

[0041] Therefore, in the present invention, the three types of monomers are polymerized in two steps respectively. First, an excessive amount of the first monomer reacts with the second monomer until the second monomer is exhausted, thereby generating an oligomer or short polymer chain of the first monomer and the second monomer, and its structure is Then it reacts with the third monomer, thereby generating a polymer chain with heterogeneous repeating units, and its structure is Finally, it may react with the free monomers present in the reaction solution and the oligomers of the first and second monomers, thereby generating the linear polyimide shown in Formula A of the present invention. By optimizing the structure of the polymer chain, the present invention can significantly improve the rheology, ultraviolet absorption ability, solubility, and high-temperature resistance of the polyimide.

[0042] In some embodiments of the present invention, the molar ratio of the first monomer, the second monomer, and the third monomer is (2 - 18):(1 - 9):(1 - 9).

[0043] Furthermore, the raw materials of step (1) further include an alkali catalyst;

[0044] The raw materials of step (2) further include a capping monomer;

[0045] The alkali catalyst is selected from at least one of organotin-based or tertiary amine-based alkali catalysts;

[0046] The capping monomer is selected from at least one of monofunctional amine monomers or monofunctional anhydride monomers.

[0047] In the preparation of the linear polyimide of the present invention, one or more capping monomers can be used to further control the termination of the polymerization reaction and the molecular weight of the polymer. By adding monomers with a single functional group, such as monofunctional amine monomers or monofunctional anhydride monomers, to the reaction mixture, the polymer chain can be terminated.

[0048] The monofunctional amine monomer is selected from at least one of aniline, benzylamine, furfurylamine, benzylamine, isobutylamine, tert-butylamine, n-propylamine, 1-naphthylamine, propargylamine, or cyanamide; the monofunctional anhydride monomer is selected from at least one of maleic anhydride, phthalic anhydride, succinic anhydride, 1,8-phthalic anhydride, or phenylacetylene-modified trimellitic anhydride. It can be understood that any of these or other suitable capping monomers can be added to the above structure to terminate the polymerization reaction.

[0049] In the preparation of the linear polyimide of the present invention, the solvent can be selected from at least one of γ-butyrolactone, dimethyl sulfoxide, N-methylpyrrolidone, dimethylacetamide, propylene glycol methyl ether acetate, benzyl alcohol, propylene glycol methyl ether, anisole, acetylene, d-limonene, or toluene;

[0050] The preferred solvent is at least one of γ-butyrolactone, dimethyl sulfoxide, N-methylpyrrolidone, or dimethylacetamide.

[0051] In the preparation of the linear polyimide of the present invention, an alkali catalyst can be used to accelerate the reaction rate.

[0052] The alkali catalyst is selected from at least one of organotin-based or tertiary amine-based, such as dibutyltin dilaurate, triethylenediamine, or triethylamine, etc.

[0053] The preparation of the linear polyimide of the present invention can remove the terminal amino groups through two-step reactions, and imidization is not required. After the reaction, there is no need to further separate the polymer, and the product can remain in the solution and be used in the form as obtained.

[0054] On the other hand, the present invention also provides a temporary bonding adhesive. Based on the total mass fraction of 100%, the temporary bonding adhesive contains 1-50 wt% of any one of the above linear polyimides, 50-99 wt% of a solvent, and 0-20 wt% of an additive;

[0055] The solvent is selected from at least one of amine solvents, ether solvents or aromatic hydrocarbon solvents.

[0056] In some embodiments of the present invention, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, n-hexane, cyclopentane, cyclohexanone, ethyl acetate, propylene glycol methyl ether or propylene glycol methyl ether acetate.

[0057] In some embodiments of the present invention, the additive is selected from at least one of a promoter, a leveling agent, an antioxidant, a wetting agent or a plasticizer.

[0058] In some embodiments of the present invention, the promoter can be triethanolamine;

[0059] In some embodiments of the present invention, the leveling agent is selected from acrylate leveling agents; the acrylate leveling agents can be polyacrylate, fluorine-modified acrylate or silicone-modified acrylate, etc.;

[0060] In some embodiments of the present invention, the antioxidant is selected from at least one of antioxidant 1010, antioxidant 168, antioxidant 1076 or antioxidant 405;

[0061] In some embodiments of the present invention, the plasticizer is selected from at least one of chlorinated paraffin, n-hexane, n-heptane, methylcyclohexane, isodecanoic acid, phosphate ester or naphthenic oil.

[0062] Finally, the present invention also provides the application of the above temporary bonding adhesive in the field of semiconductor packaging.

[0063] In some embodiments of the present invention, the viscosity of the temporary bonding adhesive in the field of semiconductor packaging can be 1-8000 cP, the film thickness can be 0.1-100 μm, and the total thickness variation TTV ≤ 3 μm.

[0064] In some embodiments of the present invention, the viscosity of the temporary bonding adhesive in the field of semiconductor packaging is preferably 2000 - 8000 cP, and most preferably 4000 - 6000 cP; the film thickness is preferably 5 - 40 μm, and most preferably 10 - 20 μm.

[0065] By controlling the viscosity, film thickness, and total thickness change of the temporary bonding adhesive, etc., the present invention can make it applicable to various sizes or processing technologies. Depending on the application scenario, when the temporary bonding adhesive of the present invention is used in an auxiliary debonding layer such as a photosensitive adhesive or a mechanical debonding layer, its viscosity is 1 - 1000 cP, usually 1 - 100 cP, and the corresponding film thickness is 0.1 - 1 μm, and the uniformity of the film thickness difference at each point of the coated film thickness < 3%; when used in the temporary bonding in the semiconductor packaging section or the Micro-LED transfer process, the film thickness is 1 μm - 60 μm, preferably 5 - 40 μm, and most preferably 10 - 20 μm; when used in the laser debonding of metal coatings, the film thickness is 0.5 - 1 μm; when used in a special double coating process, the film thickness can reach 100 μm, and after coating, the uniformity of the film thickness difference at each point of the formed film < 3%.

[0066] The temporary bonding adhesive of the present invention can generally go through the process sequence of deposition, baking, bonding, processing, debonding, and cleaning to complete the support and bonding for processes such as device thinning, polishing, and stacking, and then be applied to the field of semiconductor packaging.

[0067] Among them, the temporary bonding adhesive can be deposited in various ways, including but not limited to spin coating, blade coating, drop coating, screen printing, etc. When using the spin coating method for deposition, the rotation speed can be controlled at 100 - 5000 rpm, the acceleration is 50 - 5000 rpm / s, and the spin coating duration is 10 - 200 s;

[0068] The deposited temporary bonding adhesive can be baked under the conditions that the baking temperature of the first stage is 50 - 150 °C, the baking temperature of the second stage is 200 - 300 °C, and the duration is 5 - 60 min;

[0069] The baked temporary bonding adhesive can be bonded under the conditions that the bonding temperature is 60 - 300 °C, the bonding pressure depends on the bonding size and can be 200 N - 50000 N, and the bonding duration is 10 s - 20 min;

[0070] The bonded temporary bonding adhesive can undergo processing in process sections such as back grinding, chemical mechanical polishing, etching, metal deposition, dielectric deposition, patterning, passivation, annealing, etc., so as to complete processes such as device thinning, polishing, and stacking;

[0071] The processed temporary bonding adhesive can be debonded by scanning with an ultraviolet laser. When debonding, a laser in the wavelength range of 200 - 500 nm can be used to ablate the wafer surface in a serpentine manner. When debonding at 355 nm, the optical flux is 340 - 400 mj / cm 2 , the spot pitch is 20 - 80 μm, and the scanning speed is 2 - 4 m / s; when debonding at 266 nm, the optical flux is 50 - 150 mj / cm 2 , the spot pitch is 10 - 60 μm, and the scanning speed is 2 - 4 m / s;

[0072] The temporary bonding adhesive after debonding can be cleaned with a cleaning agent, and the cleaning agent is selected from at least one of dimethyl sulfoxide, potassium hydroxide, or amine compounds; the cleaning conditions are a temperature of 40 - 60 °C and spray rinsing for 3 - 20 min.

[0073] Advantages:

[0074] (1) The linear polyimide provided by the present invention, by controlling the selection of monomers, on the one hand, can endow the polyimide with heat resistance and photosensitivity, enabling it to have ultraviolet light absorption ability and can be debonded under ultraviolet light; on the other hand, it can improve the flexibility and fluidity of the polyimide, enabling it to have a certain bonding ability.

[0075] (2) The preparation method of the linear polyimide provided by the present invention polymerizes three types of monomers through two-step reactions, making the prepared linear polyimide have a polymer chain with heterogeneous repeating units, further optimizing the rheological properties, ultraviolet absorption ability, and bonding ability of the linear polyimide.

[0076] (3) The temporary bonding adhesive provided by the present invention, by adding linear polyimide as the main resin and adjusting the selection of the solvent and the proportion of each component, enables the prepared temporary bonding adhesive to have excellent high-temperature resistance, and at the same time has bonding ability and the ability to absorb ultraviolet light for debonding.

[0077] (4) The temporary bonding adhesive provided by the present invention can be widely applied in the field of semiconductor packaging. On the one hand, it has both bonding ability and ultraviolet absorption ability, avoiding the combined use of multiple colloids, which can reduce the production cost and process complexity; on the other hand, it has excellent high-temperature resistance and can withstand various high-temperature processes, expanding the application range; and it can be debonded by ultraviolet light, with simple cleaning and no residual glue after cleaning. Specific Embodiments

[0078] The following will illustrate the present invention in conjunction with specific implementation schemes. It should be noted that the following examples are examples of the present invention, only used to illustrate the present invention, and not used to limit the present invention. Other combinations and various improvements within the concept of the present invention can be made without departing from the main idea or scope of the present invention.

[0079] The polyethylene glycol diamine and polyether diamine are sourced from Shanghai Aladdin Biochemical Technology Co., Ltd.; the commercially available linear polyimide is AURUM PL500M purchased from Mitsui Chemicals, Japan; the commercially available temporary bonding adhesive is WaferBond HT-10.10 from Brewer Science; the remaining reagents and equipment are conventional reagents and equipment in this technical field.

[0080] Linear polyimide-1

[0081] Linear polyimide-1 is prepared through the following steps:

[0082] (1) In a reactor equipped with a water separator condenser, after introducing nitrogen, 0.08 mol of 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 0.04 mol of 3,3'-diaminodiphenylmethane, and 0.3 g of triethylamine are added. While stirring at room temperature, 50 mL of the solvent N-methylpyrrolidone is added, and the mixture is heated to 150 °C for a copolymerization reaction for 6 h until the reaction is completed.

[0083] (2) 0.04 mol of polyether diamine with a molecular weight of 1200 is added to the reactor in step (1). After reacting for 6 h, aniline is added and the reaction is carried out for 30 min to obtain a reddish-brown solution, which is the said linear polyimide-1.

[0084] The product is subjected to infrared detection using a Fourier transform infrared spectrometer, and its characteristic peaks are recorded as 1770 cm -1 , 1710 cm -1 , 1350 cm -1 .

[0085] Linear polyimide-2

[0086] It is basically the same as Preparation Example 1, except that 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride is replaced with an equal amount of 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and 3,3'-diaminodiphenylmethane is replaced with an equal amount of 4,4'-diaminodiphenyl ether.

[0087] The product is subjected to infrared detection using a Fourier transform infrared spectrometer, and its characteristic peaks are recorded as 1760 cm -1 , 1700 cm -1 , 1230 cm -1 , 1330 cm -1 .

[0088] Linear polyimide-3

[0089] It is basically the same as Preparation Example 1, except that the molecular weight of the polyether diamine is changed to 4000.

[0090] Linear polyimide-4

[0091] Basically the same as Preparation Example 1, except that the polyether diamine was replaced with an equal amount of polyethylene glycol diamine with a molecular weight of 1200.

[0092] The product was detected by Fourier transform infrared spectrometer, and its characteristic peaks were recorded as 1770 cm -1 , 1720 cm -1 , 1140 cm -1 , 1340 cm -1 .

[0093] Linear polyimide-5

[0094] Basically the same as Preparation Example 1, except that 3,3',4,4'-diphenylether tetracarboxylic dianhydride was replaced with an equal amount of bis(3,4-dicarboxyphenyl)ether dianhydride.

[0095] The product was detected by Fourier transform infrared spectrometer, and its characteristic peaks were recorded as 1790 cm -1 , 1730 cm -1 , 1360 cm -1 .

[0096] Linear polyimide-6

[0097] Basically the same as Preparation Example 1, except that 3,3'-diaminodiphenylmethane was replaced with an equal amount of 9,9-bis(4-aminophenyl)fluorene.

[0098] The product was detected by Fourier transform infrared spectrometer, and its characteristic peaks were recorded as 1740 cm -1 , 1735 cm -1 , 1450 cm -1 , 1360 cm -1 .

[0099] Linear polyimide-7

[0100] Basically the same as Preparation Example 1, except that the polyether diamine was replaced with an equal amount of 1,2-propanediamine.

[0101] The product was detected by Fourier transform infrared spectrometer, and its characteristic peaks were recorded as 1765 cm -1 , 1725 cm -1 , 1335 cm -1 .

[0102] Linear polyimide-8

[0103] Basically the same as Preparation Example 1, except that 3,3',4,4'-diphenylether tetracarboxylic dianhydride was replaced with an equal amount of bis(3,4-dicarboxyphenyl)ether dianhydride, polyether diamine was replaced with an equal amount of 1,2-propanediamine, and 3,3'-diaminodiphenylmethane was replaced with an equal amount of 9,9-bis(4-aminophenyl)fluorene.

[0104] The product was detected by Fourier transform infrared spectrometer, and its characteristic peaks were recorded as 1780 cm -1 , 1720 cm -1 , 1340 cm -1 .

[0105] Linear polyimide-9

[0106] Linear polyimide-9 was prepared through the following steps:

[0107] In a reactor equipped with a water-separating condenser, after introducing nitrogen, 0.08 mol of 3,3',4,4'-diphenylether tetracarboxylic dianhydride, 0.04 mol of 3,3'-diaminodiphenylmethane, 0.04 mol of polyether diamine with a molecular weight of 1200, and 0.3 g of dibutyltin dilaurate were added. While stirring at room temperature, 50 mL of the solvent N-methylpyrrolidone was added, and the mixture was heated to 150 °C. After copolymerization for 12 h, the linear polyimide-9 was obtained.

[0108] The product was detected by Fourier transform infrared spectrometer, and its characteristic peaks were recorded as 1750 cm -1 , 1720 cm -1 , 1340 cm -1 .

[0109] Linear polyimide-10

[0110] Commercially available linear polyimide.

[0111] Example 1

[0112] The temporary bonding adhesive of the present invention, based on a total mass fraction of 100%, contains 30 wt% of linear polyimide-1, 40 wt% of N,N-dimethylformamide, and 30 wt% of propylene glycol methyl ether.

[0113] Example 2

[0114] The temporary bonding adhesive of the present invention, based on a total mass fraction of 100%, contains 20 wt% of linear polyimide-1, 35 wt% of N,N-dimethylformamide, 35 wt% of propylene glycol methyl ether, and 10 wt% of the accelerator triethanolamine.

[0115] Example 3

[0116] The temporary bonding adhesive described in the present invention, based on a total mass fraction of 100%, contains 25 wt% of linear polyimide-2 and 75 wt% of N,N-dimethylformamide.

[0117] Example 4

[0118] The temporary bonding adhesive described in the present invention, based on a total mass fraction of 100%, contains 20 wt% of linear polyimide-3 and 80 wt% of propylene glycol methyl ether.

[0119] Example 5

[0120] The temporary bonding adhesive described in the present invention, based on a total mass fraction of 100%, contains 20 wt% of linear polyimide-4, 40 wt% of N,N-dimethylformamide and 40 wt% of propylene glycol methyl ether.

[0121] Example 6

[0122] The temporary bonding adhesive described in the present invention, based on a total mass fraction of 100%, contains 20 wt% of linear polyimide-5, 40 wt% of N,N-dimethylformamide and 40 wt% of propylene glycol methyl ether.

[0123] Example 7

[0124] The temporary bonding adhesive described in the present invention, based on a total mass fraction of 100%, contains 20 wt% of linear polyimide-6, 40 wt% of N,N-dimethylformamide and 40 wt% of propylene glycol methyl ether.

[0125] Comparative Example 1

[0126] Commercially available temporary bonding adhesive.

[0127] Comparative Example 2

[0128] A temporary bonding adhesive, based on a total mass fraction of 100%, contains 30 wt% of linear polyimide-7, 40 wt% of N,N-dimethylformamide and 30 wt% of propylene glycol methyl ether.

[0129] Comparative Example 3

[0130] A temporary bonding adhesive, based on a total mass fraction of 100%, contains 30 wt% of linear polyimide-8, 40 wt% of N,N-dimethylformamide and 30 wt% of propylene glycol methyl ether.

[0131] Comparative Example 4

[0132] A temporary bonding adhesive, based on a total mass fraction of 100%, contains 30 wt% of linear polyimide-9, 40 wt% of N,N-dimethylformamide and 30 wt% of propylene glycol methyl ether.

[0133] Comparative Example 5

[0134] A temporary bonding adhesive, calculated based on a total mass fraction of 100%, contains 30 wt% of linear polyimide-10, 40 wt% of N,N-dimethylformamide, and 30 wt% of propylene glycol methyl ether.

[0135] Application Example 1

[0136] Bonding and debonding are carried out using the temporary bonding adhesive through the following steps:

[0137] (1) The temporary bonding adhesive of Example 1 is deposited on the wafer surface by a Leibo AC200 spin coater through spin coating at a rotation speed of 1500 rpm, an acceleration of 800 rpm / s, and a spin coating duration of 30 s;

[0138] (2) The spin-coated temporary bonding adhesive is subjected to a first-stage baking at a temperature of 100 °C and a second-stage baking at a temperature of 280 °C for 20 min using a Leibo HP100-SE baking machine;

[0139] (3) The baked temporary bonding adhesive is bonded under the conditions of a temperature of 180 °C, a bonding pressure of 1500 N, and a bonding duration of 3 min;

[0140] (4) The bonded temporary bonding adhesive is scanned and debonded in a serpentine manner across the wafer surface using a 355 nm wavelength ultraviolet laser, with a light flux of 340 - 400 mj / cm 2 , a spot pitch of 60 μm, a scanning speed of 2 - 4 m / s. After laser debonding, the cleaning agent dimethyl sulfoxide is added, and it is rinsed by spraying with the cleaning agent at a temperature of 50 °C for 10 min to be cleaned.

[0141] Application Examples 2 - 12

[0142] Basically the same as Application Example 1, except that the temporary bonding adhesives are replaced with the temporary bonding adhesives of Examples 2 - 7 and Comparative Examples 1 - 5 respectively.

[0143] Performance Test

[0144] 1. Detection of Linear Polyimide Performance

[0145] Detection of weight-average molecular weight: Under the conditions of a mobile phase of DNF and a reference of polystyrene, the weight-average molecular weights of the above linear polyimides 1 - 10 are detected;

[0146] Detection of heat resistance: Under the conditions of a heating rate of 20 °C / min, a temperature range of 20 - 700 °C, and a nitrogen atmosphere, the above linear polyimides 1 - 10 are heated, and the temperature at which their weight loss is 5% is recorded;

[0147] 355 nm Absorbance Detection: Use a 355 nm laser beam to detect the ultraviolet light absorbance of the above linear polyimides 1 - 10.

[0148] The detection results are shown in Table 1 below:

[0149] Table 1 Performance Detection Results of Linear Polyimides 1 - 10

[0150] Weight-average molecular weight (Da) Heat resistance Td, 5% (°C) Absorbance at 355 nm (%) Linear polyimide-1 86953 606 99.8 Linear polyimide-2 75620 591 99.4 Linear polyimide-3 82523 593 98.8 Linear polyimide-4 81230 586 97.5 Linear polyimide-5 76216 584 96.4 Linear polyimide-6 78142 587 98.3 Linear polyimide-7 71235 528 94.6 Linear polyimide-8 70952 506 94.3 Linear polyimide-9 78962 533 96.3 Linear polyimide-10 76120 508 93.8

[0151] According to the comparison of the performance detection results of linear polyimides 1 - 6 and linear polyimide 10, it can be seen that the linear polyimide provided by the present invention has excellent high-temperature resistance and ultraviolet light absorption ability.

[0152] According to the comparison of the performance detection results of linear polyimides 1 - 6 and linear polyimide 7, it can be seen that in the linear polyimide provided by the present invention, choosing polyethylene glycol diamine or polyether diamine as the third monomer, the polyimide polymerized from the diamine monomers in the prior art has more excellent high-temperature resistance and ultraviolet light absorption ability.

[0153] According to the comparison of the performance detection results of linear polyimides 1 - 6 and linear polyimide 8, it can be seen that through the selection and combination of three types of monomers in the linear polyimide provided by the present invention, the rigid structure and flexible structure between the monomers cooperate with each other, so that the prepared linear polyimide has excellent heat resistance and ultraviolet light absorption ability at the same time.

[0154] According to the comparison of the performance detection results of linear polyimides 1 - 6 and linear polyimide 9, it can be seen that for the linear polyimide provided by the present invention, the three types of monomers are polymerized through two-step reactions, so that the prepared linear polyimide has a polymer chain with heterogeneous repeating units, further optimizing the rheology, ultraviolet absorption ability and adhesion ability of the linear polyimide.

[0155] According to the comparison of the performance detection results of linear polyimide 1 and linear polyimide 4, it can be seen that choosing polyether diamine as the third monomer in the linear polyimide provided by the present invention has better solubility, rheology and adhesion than polyethylene glycol diamine, and can further improve the overall performance of the linear polyimide.

[0156] 2. Temporary Bonding Adhesive Performance Detection

[0157] Viscosity Detection: Detect the viscosities of the temporary bonding adhesives in Examples 1 - 7 and Comparative Examples 1 - 5 above, respectively;

[0158] TTV and film thickness detection: Taking a 4-inch sapphire wafer as an example, the spin coating verification was carried out using the temporary bonding adhesives of the above Examples 1-7 and Comparative Examples 1-5. After spin coating, the sapphire wafer was placed in an oven at 100 °C for 30 s to volatilize the solvent. The dried sapphire wafer was taken out, and a thickness gauge was used to detect the film thickness and TTV of the sapphire wafer after coating.

[0159] Heat resistance detection: Under the conditions of a heating rate of 20 °C / min, a temperature range of 20-700 °C, and a nitrogen atmosphere, the temporary bonding adhesives of the above Examples 1-7 and Comparative Examples 1-5 were heated, and the temperature at which the weight loss was 5% was recorded.

[0160] The test results are shown in Table 2 below:

[0161] Table 2 Performance test results of Examples 1-7 and Comparative Examples 1-5

[0162]

[0163]

[0164] According to the comparison of the performance test results of Examples 1-7 and Comparative Example 1, the temporary bonding adhesive provided by the present invention has excellent high-temperature resistance, and at the same time has bonding ability and ultraviolet light absorption ability, which can avoid the combined use of multiple colloids and reduce the manufacturing cost.

[0165] According to the comparison of the performance test results of Examples 1-7 and Comparative Examples 2-5, the temporary bonding adhesive provided by the present invention uses linear polyimide as the main resin. Through the excellent performance of linear polyimide, the prepared temporary bonding adhesive has both bonding ability and ultraviolet light absorption ability, and has excellent high-temperature resistance.

[0166] According to the performance test results of Examples 1-7, the temporary bonding adhesive provided by the present invention uses linear polyimide as the main resin, and by adjusting the selection of solvents and additives and the proportions of each component, the high-temperature resistance, bonding ability and ultraviolet light absorption ability of the temporary bonding adhesive can be further enhanced.

[0167] 3. Application ability detection

[0168] Bonding strength detection: Taking a 4-inch sapphire wafer as an example, the spin coating verification was carried out for the above Application Examples 1-12. The test horizontal probe surface of the electronic tensile tester was fixed on the surface of the sapphire wafer through the bonding adhesive. The tensile tester was turned on, and the tensile rate was 10 mm / min until the sapphire wafer was separated from the horizontal probe, which was the bonding strength of the bonding adhesive.

[0169] Cleaning ability detection: Observe whether there is residual adhesive left after the cleaning of the above Application Examples 1-12 is completed.

[0170] The test results are shown in Table 3 below:

[0171] Table 3 Performance Detection Results of Application Examples 1 - 12

[0172]

[0173]

[0174] From the comparison of the detection results between Application Examples 1 - 7 and Application Example 8, it can be seen that the temporary bonding adhesive provided by the present invention has excellent bonding ability, is easy to clean, and has no residual glue after cleaning, and can be widely applied in the field of semiconductor packaging.

[0175] From the comparison of the detection results between Application Examples 1 - 7 and Application Examples 9 - 12, it can be seen that the temporary bonding adhesive provided by the present invention uses linear polyimide as the main resin. On the one hand, it can endow the temporary bonding adhesive with both excellent bonding ability and ultraviolet light absorption ability, avoid the compound use of multiple adhesives, reduce the production cost and process complexity; on the other hand, it has excellent high-temperature resistance, can withstand various high-temperature processes, expand the application range; and can be debonded by ultraviolet light, with simple cleaning and no residual glue after cleaning.

[0176] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those familiar with this technology to understand the content of the present invention and implement it, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A linear polyimide, characterized in that, It has the structure shown in Formula A below: ， Wherein, x:y:z = (1 - 9):(1 - 9):(0 - 9); The weight-average molecular weight of the linear polyimide is 5,000 - 100,000; The first monomer is selected from at least one of tetracarboxylic dianhydrides; The second monomer is selected from at least one of aromatic diamines; The third monomer is selected from at least one of polyethylene glycol diamine or polyether diamine.

2. The linear polyimide according to claim 1, wherein The first monomer is selected from at least one of 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, pyromellitic dianhydride or 1,2,4,5-cyclohexane tetracarboxylic dianhydride; The second monomer is selected from at least one of 1,4-phenylenediamine, 4,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)benzene, 4,4'-diamino-3,3'-dimethyl diphenylmethane or 3,3'-diaminodiphenylmethane; The third monomer is selected from at least one of polyethylene glycol diamine with a molecular weight of 400 - 10,000 or polyether diamine with a molecular weight of 200 - 5,000.

3. The linear polyimide according to claim 2, characterized in that, The third monomer is selected from polyether diamine with a molecular weight of 200 - 5,000.

4. The linear polyimide according to claim 1, characterized in that, The decomposition temperature Td of the linear polyimide > 580 °C, and the ultraviolet light absorption rate at 355 nm > 98%.

5. The preparation method of the linear polyimide according to any one of claims 1-4, characterized in that, It includes the following steps: (1) In a reactor, add the first monomer and the second monomer and copolymerize until the reaction is complete; (2) Add the third monomer to the reactor in step (1) and copolymerize until the reaction is complete to obtain the linear polyimide.

6. The preparation method of the linear polyimide according to claim 5, characterized in that, The molar ratio of the first monomer, the second monomer and the third monomer is (2 - 18):(1 - 9):(1 - 9).

7. The preparation method of the linear polyimide according to claim 5, characterized in that, The raw materials in step (1) further include an alkali catalyst; The raw materials in step (2) further include a capping monomer; The alkali catalyst is selected from at least one of organotin-based or tertiary amine-based alkali catalysts; The capping monomer is selected from at least one of monofunctional amine monomers or monofunctional acid anhydride monomers.

8. A temporary bonding adhesive, characterized in that, Calculated by the total mass fraction of 100%, the temporary bonding adhesive contains 1 - 50 wt% of the linear polyimide according to any one of claims 1 - 4, 50 - 99 wt% of a solvent and 0 - 20 wt% of an additive; The solvent is selected from at least one of amine solvents, ether solvents or aromatic hydrocarbon solvents.

9. The temporary bonding adhesive according to claim 8, wherein, The solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, n-hexane, cyclopentane, cyclohexanone, ethyl acetate, propylene glycol methyl ether or propylene glycol methyl ether acetate.

10. The temporary bonding adhesive according to claim 8, wherein The additive is selected from at least one of a promoter, a leveling agent, an antioxidant, a wetting agent or a plasticizer.

11. Application of the temporary bonding adhesive according to any one of claims 8 - 10 in the field of semiconductor packaging.

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