Temporary bonding adhesive, and preparation method therefor and use thereof

Abstract

The present application provides a temporary bonding adhesive, and a preparation method therefor and a use thereof. Raw materials for preparing the temporary bonding adhesive include the following components in percentage by weight: 60-80% of an organic solvent; 20-35% of a base resin; 0.1-1% of a tackifying resin; 0.1-1% of an antioxidant; and 0.1-1% of a wetting and leveling agent. The temporary bonding adhesive provided by the present application has properties such as high hardness, smooth film surface, high adhesion and strong chemical corrosion resistance, and can be widely applied to wafer processing.

Description

Temporary bonding adhesive and preparation method and application thereof TECHNICAL FIELD

[0001] The application belongs to the technical field of bonding adhesive, and relates to a temporary bonding adhesive and a preparation method and application thereof, in particular to a temporary bonding adhesive for wafer-level packaging and a preparation method and application thereof. BACKGROUND

[0002] The temporary bonding adhesive is an intermediate layer material for bonding a functional wafer and a temporary carrier together, and is also a key material for wafer thinning process. From the aspect of the temporary bonding adhesive material, on the one hand, it is required to tightly bond wafer stacks together so that the functional wafer is reliably supported and protected, and can withstand mechanical force, chemical corrosion and high-temperature processing in subsequent processes; on the other hand, it is required to be able to safely separate the functional wafer and the temporary carrier through a simple method after processing.

[0003] CN104204126A discloses an adhesive composition for wafer processing film, which is mainly used for temporarily fixing wafers in wafer processing processes such as cutting or back grinding, or for protecting and reinforcing wafers, and the composition contains an acrylic polymer and a photosensitive gas generating agent, which can increase wafer wettability and avoid wafer bottom biting. However, the above-mentioned patent has the following defects and deficiencies, the temporary bonding composition is reaction type, has large shrinkage force during curing, poor film surface uniformity and local distortion during wafer bonding, resulting in weak chemical liquid resistance of the prepared wafer.

[0004] Therefore, in the field, it is desirable to develop a temporary bonding adhesive with good chemical liquid resistance, heat resistance, high bonding performance and easy cleaning characteristics. SUMMARY

[0005] The application provides a temporary bonding adhesive and a preparation method and application thereof. The temporary bonding adhesive provided by the application has high hardness, smooth film surface, strong bonding force and strong chemical corrosion resistance, and can be widely used in wafer processing.

[0006] In a first aspect, the application provides a temporary bonding adhesive, and the preparation raw materials of the temporary bonding adhesive comprise the following components according to weight percentage:

[0007] In the application, specific base resin and specific tackifying resin are compounded, which not only improves the thermal stability of the temporary bonding adhesive, so that it does not have adverse reactions such as decomposition or polymerization at high temperature, but also makes the film layer have strong bonding force, so that the prepared wafer bonding pair can avoid immersion of high-polarity solvents and strong acid and alkali solutions, and the chemical liquid resistance of the wafer bonding pair is improved.

[0008] The temporary bonding glue provided in the application has excellent mechanical strength, and the uneven stress phenomenon does not occur in the processing process, which can provide sufficient support force for the wafer and prevent the wafer from breaking and other risks in the grinding and polishing process.

[0009] In the application, the amount of the organic solvent in the preparation raw material of the temporary bonding glue can be 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78% or 80% and the like according to the percentage by weight.

[0010] In the application, the amount of the base resin in the preparation raw material of the temporary bonding glue can be 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34% or 35% and the like according to the percentage by weight.

[0011] In the application, the amount of the tackifying resin in the preparation raw material of the temporary bonding glue can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1% and the like according to the percentage by weight.

[0012] In the application, the amount of the antioxidant in the preparation raw material of the temporary bonding glue can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1% and the like according to the percentage by weight.

[0013] In the application, the amount of the wetting and leveling agent in the preparation raw material of the temporary bonding glue can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1% and the like according to the percentage by weight.

[0014] Preferably, the organic solvent includes any one or a combination of at least two of cyclic hydrocarbon solvents (such as p-xylene, ethylcyclohexane, isopropylcyclohexane and the like), ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate or propylene glycol monomethyl ether, preferably p-xylene / ethylene glycol butyl ether acetate, p-xylene / propylene glycol monomethyl ether acetate, ethylcyclohexane / ethylene glycol butyl ether acetate or propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether two combined solvents.

[0015] Preferably, the base resin comprises a thermoplastic polymeric resin, which comprises any one or a combination of at least two of a polyketone resin (POK), a polyphenylene ether resin (PPO), a polyphenylsulfone resin (PPSU), a block copolymer of acrylic acid (MAM), a styrene-methyl methacrylate copolymer (MS), a styrene-acrylonitrile resin (SAN), or a polymethyl methacrylate resin (PMMA), preferably any one or a combination of at least two of a MAM resin, a MS resin, or a PPSU resin, with a molecular weight ranging from 50000 to 200000.

[0016] Preferably, the tackifying resin comprises any one or a combination of at least two of a poly-alpha-methylstyrene resin, a styrene-C9 monomer copolymer, a styrene-terpene resin, or a dicyclopentadiene resin.

[0017] Preferably, the antioxidant comprises any one or a combination of at least two of a hindered phenolic antioxidant, a phosphite antioxidant, or other antioxidant.

[0018] Preferably, the hindered phenolic antioxidant comprises antioxidant 1010 and / or antioxidant 1076.

[0019] Preferably, the phosphite antioxidant comprises antioxidant 168 and / or antioxidant 626.

[0020] Preferably, the other antioxidant comprises any one or a combination of at least two of antioxidant 164, antioxidant TPP, or antioxidant DNP.

[0021] Preferably, the wetting and leveling agent comprises any one or a combination of at least two of an acrylate wetting and leveling agent, a silicone wetting and leveling agent, or other wetting and leveling agent.

[0022] Preferably, the acrylate wetting and leveling agent comprises BYK-361N and / or BYK-397.

[0023] Preferably, the silicone wetting and leveling agent comprises BYK-323 and / or BYK-378.

[0024] Preferably, the other wetting and leveling agent comprises a modified succinic acid and ester mixture, such as BYK-3410, etc.

[0025] The specific wetting and leveling agent selected in the present application can effectively reduce the surface tension of the bonding adhesive, improve the spreading ability of the bonding adhesive on the substrate surface, enable the bonding adhesive to be uniformly spin-coated on the wafer surface, avoid uneven coating thickness, and reduce the occurrence of air bubbles and slip sheets during wafer bonding, etc. The addition of the leveling agent ensures uniform film surface while having no effect on the adhesion performance of the film layer.

[0026] In a second aspect, the present application provides a preparation method of the temporary bonding glue according to the first aspect, the preparation method comprising the following steps:

[0027] (1) adding an organic solvent into a stirrer, starting stirring, and starting a cooling water circulation system at the same time;

[0028] (2) adding a wetting and leveling agent and an antioxidant into the stirrer in step (1) in sequence, stirring until a clear and transparent liquid is formed;

[0029] (3) adding a base resin and a tackifying resin into the stirrer in step (2) in sequence, stirring until a clear and transparent liquid is formed, and filtering to obtain the temporary bonding glue.

[0030] Preferably, the stirrer in step (1) comprises a stirring tank.

[0031] Preferably, the temperature of the cooling water circulation system in step (1) is controlled at 25-40℃, such as 25℃, 30℃, 35℃ or 40℃, etc.

[0032] Preferably, the stirring in step (1) is mechanical stirring at a speed of 50-100 rpm, such as 50 rpm, 60 rpm, 80 rpm or 100 rpm, etc.

[0033] Preferably, the temperature in step (2) is controlled at 25-40℃, such as 25℃, 30℃, 35℃ or 40℃, etc., the stirring speed is 50-100 rpm, such as 50 rpm, 60 rpm, 80 rpm or 100 rpm, etc., and the stirring time is 10-30 min, such as 10 min, 15 min, 20 min, 25 min or 30 min, etc.

[0034] Preferably, the temperature in step (3) is controlled at 25-40℃, such as 25℃, 30℃, 35℃ or 40℃, etc., the stirring speed is 50-70 rpm, such as 50 rpm, 60 rpm or 70 rpm, etc., the stirring time is 15-20 h, such as 15 h, 16 h, 18 h or 20 h, etc., and preferably 15-16 h.

[0035] Preferably, the filter core in step (3) has a precision grade of 1-10 μm, such as 1 μm, 3 μm, 5 μm, 8 μm or 10 μm, etc., and preferably 2-5 μm.

[0036] In a third aspect, the present application provides an application of the temporary bonding glue according to the first aspect in a wafer processing process.

[0037] Preferably, the application method comprises the following steps:

[0038] The temporary bonding glue is heated to solidify and form a bonding layer, and finally a cleaning agent (such as Samcien Remover 3) is used to clean the residual bonding layer on the periphery of the wafer.

[0039] Exemplarily, the application method of the temporary bonding glue in the wafer processing process comprises the following steps:

[0040] (a) Place a 12-inch wafer on a spin coater, start the vacuum system, fix the wafer with a suction cup, pour 30-40 mL of the temporary bonding glue uniformly on the wafer, start the spin coating, and set the spin coating parameters as follows: first spin at 200-400 rpm for 30-40 s, and then spin at 1000-1500 rpm for 20-30 s;

[0041] (b) Turn off the vacuum suction cup, take out the wafer coated with the temporary bonding glue, and place it in an oven at 90-100°C for baking for 5-10 min, preferably 5 min; then place it in an oven at 200-230°C for baking for 5-10 min, preferably 5 min;

[0042] (c) Similarly, spin the laser release protective material on a 12-inch carrier, and set the spin coating parameters as follows: first spin at 300-500 rpm for 5-10 s, and then spin at 1500-2000 rpm for 20-30 s; and set the baking conditions as follows: first stage 115-150°C, 5-10 min, second stage 350-380°C, 20-30 min;

[0043] (d) After baking, bond the wafer coated with the temporary bonding glue and the carrier coated with the protective layer on the surface of the carrier table, heat to 200-230°C, pressurize 20-40 kN, bond for 5-10 min (preferably 10 min), and cool to room temperature to complete the temporary bonding of the wafer.

[0044] Compared with the prior art, the application has the following beneficial effects:

[0045] (1) The application uses specific base resin and specific tackifying resin for compounding, which not only improves the thermal stability of the temporary bonding glue, but also improves the chemical liquid resistance of the wafer bonding pair.

[0046] (2) The temporary bonding glue provided by the application has excellent mechanical strength, and the processing process will not appear uneven stress phenomenon, which can provide sufficient support force for the wafer to prevent the wafer from breaking and other risks in the grinding and polishing process. BRIEF DESCRIPTION OF DRAWINGS

[0047] FIG. 1 is a surface effect diagram of a temporary bonding adhesive coating film provided by Embodiment 1 of the present application. DETAILED DESCRIPTION

[0048] The technical solutions of the present application are further illustrated by specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0049] Unless otherwise specified, the raw material information involved in the following specific embodiments of the present application is shown in Table 1. For other raw materials not shown, they are conventional materials in the art and can be purchased through commercially available products.

[0050] Table 1

[0051] Embodiments 1-7 and Comparative Examples 1-4

[0052] Embodiments 1-7 and Comparative Examples 1-4 each provide a temporary bonding adhesive, and the preparation raw materials and amounts thereof are shown in Table 2. In Table 2, the amount of each component is in "kg".

[0053] Table 2

[0054] The preparation method of the temporary bonding adhesive provided by Embodiments 1-7 and Comparative Examples 1-4 includes the following steps:

[0055] The organic solvent is added to a stirred tank with mechanical stirring and a circulating water cooling system, and the stirring is started at a speed of 70 rpm. The wetting leveling agent and the antioxidant are added while stirring, and the stirring is uniform. Then the base resin and the tackifying resin are added to the stirred tank, and the temperature change in the tank is observed during the period. If the temperature rises too fast, the circulating cooling water temperature is adjusted to control the temperature at 40°C, and the stirring is continued for 16 hours. When the material in the tank becomes clear and transparent, the stirring can be stopped, and the temporary bonding adhesive is obtained by filtering the discharged material.

[0056] Performance test:

[0057] The test method of the physicochemical properties involved in the above embodiments and comparative examples is as follows:

[0058] (1) Appearance of the adhesive and viscosity at room temperature: the appearance of the adhesive is visually observed, and the viscosity of the bonding adhesive at room temperature is measured using a Brookfield viscometer;

[0059] (2) Film surface condition and TTV: whether wrinkles or adhesive deficiency occurs at the edge of the coating is observed using a microscope, and the uniformity of the film surface is measured using a U.S. Corning Flatmaster 200 flatness tester;

[0060] (3) Film hardness: The film hardness was tested according to the test method provided in GB / T 21838-2008 "Instrumented indentation testing of hard materials and materials parameters"; the test sample was a wafer coated with the adhesive;

[0061] (4) High-temperature rheological viscosity: The rheological viscosity of the adhesive was determined by using an Anton Paar rheometer;

[0062] (5) Film adhesion: The adhesive was spin-coated on a 6-inch wafer, dried, and then the adhesion of the adhesive was determined by using a BLD-200N electronic peeling tester;

[0063] (6) Bonding pair condition: The test sample was a bonded wafer, and the bonded wafer was observed by visual observation and microscopic observation to determine whether there were snowflake-shaped bubbles on the bonded wafer;

[0064] (7) Resistance to chemical solution corrosion: The temporarily bonded wafer was immersed in a chemical solution (65% concentrated nitric acid), taken out after a period of immersion (60°C, 1 h), washed with water, and dried; the edge of the temporarily bonded wafer was observed by visual observation to determine whether there was a white dissolution phenomenon; if the white dissolution phenomenon was found, it was considered as visible corrosion; if the white dissolution phenomenon was not found, it was considered as no visible corrosion; in addition, the depth of the corrosion of the edge of the temporarily bonded wafer was observed by using a microscope.

[0065] The temporarily bonded adhesives provided in Examples 1 to 7 and Comparative Examples 1 to 4 were tested according to the above test methods, and the test results are shown in Table 3.

[0066] Table 3

[0067] Table 3 (continued)

[0068] As can be seen from Table 3, the temporarily bonded adhesives prepared in Examples 1 to 7 have uniform film thickness, reliable adhesion, no bonding defects, and good resistance to chemical solution when used for wafer processing. The coating film surface effect diagram of the temporarily bonded adhesive provided in Example 1 is shown in FIG. 1, and it can be seen that the coating film edge uniformity is excellent.

[0069] When the temporarily bonded adhesives provided in Comparative Examples 1 to 2 are used for wafer processing, the coating film uniformity is poor, the adhesion is poor, and the wafer bonding pair has poor resistance to chemical solution.

[0070] When the temporarily bonded adhesive provided in Comparative Example 3 is used for wafer processing, the coating film uniformity is excellent, the adhesion is good, and the resistance to chemical solution is good, but the prepared bonding adhesive has a too large viscosity at room temperature, which is not conducive to construction; the prepared film hardness is low and cannot provide sufficient support for the wafer, resulting in a risk of wafer breakage during grinding and thinning process; and the high-temperature rheological viscosity is high, which requires a very high bonding process to complete wafer bonding, resulting in large energy consumption.

[0071] When the temporary bonding glue provided by Comparative Example 4 is used for wafer processing, the wafer bonding pair is weak to chemical liquid due to weak film layer adhesion, and the wafer may slip in the grinding and polishing process due to insufficient coating adhesion, affecting product yield.

[0072] The applicant declares that the temporary bonding glue, the preparation method and the application thereof of the present application are illustrated by the above examples, but the present application is not limited to the above examples, that is, the present application does not mean that it must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the raw materials selected by the present application, addition of auxiliary ingredients, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A temporary bonding adhesive, the raw materials for preparing the same comprising the following components in terms of percentage by weight:

2. The temporary bonding adhesive of claim 1, wherein, The organic solvent includes any one of cyclic hydrocarbon solvents, ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, or a combination of at least two of them.

3. The temporary bonding adhesive according to claim 2, wherein the cyclic hydrocarbon solvent includes any one of p-menthane, ethylcyclohexane, isopropylcyclohexane, or a combination of at least two of them.

4. The temporary bonding adhesive according to any one of claims 1 to 3, wherein, The base resin includes a thermoplastic polymer resin, which includes any one of polyketone resin, polyphenylene ether resin, polyphenylsulfone resin, block copolymer of acrylic acid, styrene-methyl methacrylate copolymer, styrene-acrylonitrile resin, or polymethyl methacrylate resin, or a combination of at least two of them.

5. The temporary bonding adhesive according to any one of claims 1 to 4, wherein, The tackifying resin includes any one of poly-alpha-methylstyrene resin, styrene-C9 monomer copolymer, styrene-terpene resin, or dicyclopentadiene resin, or a combination of at least two of them.

6. The temporary bonding adhesive according to any one of claims 1 to 5, wherein, The antioxidant includes any one of hindered phenolic antioxidant, phosphite antioxidant, or other antioxidant, or a combination of at least two of them.

7. The temporary bonding adhesive of claim 6, wherein, The hindered phenolic antioxidant includes antioxidant 1010 and / or antioxidant 1076; Preferably, the phosphite antioxidant includes antioxidant 168 and / or antioxidant 626; Preferably, the other antioxidant includes any one of antioxidant 164, antioxidant TPP, or antioxidant DNP, or a combination of at least two of them.

8. The temporary bonding adhesive according to any one of claims 1 to 7, wherein, The wetting and leveling agent includes any one of acrylate wetting and leveling agent, silicone wetting and leveling agent, or other wetting and leveling agent, or a combination of at least two of them.

9. The temporary bonding adhesive of claim 8, wherein, The acrylate wetting and leveling agent includes BYK-361N and / or BYK-397; Preferably, the silicone wetting and leveling agent includes BYK-323 and / or BYK-378; Preferably, the other wetting and leveling agent includes a mixture of modified succinic acid and ester.

10. A method for preparing the temporary bonding adhesive according to any one of claims 1-9, comprising the following steps: (1) adding an organic solvent into a stirrer, starting stirring, and starting a cooling water circulation system at the same time; (2) adding a wetting and leveling agent and an antioxidant into step (1), stirring until a clear and transparent liquid is formed; (3) adding a base resin and a tackifying resin into step (2), stirring until a clear and transparent liquid is formed, and filtering to obtain the temporary bonding adhesive.

11. The production method according to claim 10, wherein The stirrer in step (1) includes a stirred tank. Preferably, the temperature of the cooling water circulation system in step (1) is controlled at 25-40°C. Preferably, the stirring in step (1) is mechanical stirring at a speed of 50-100 rpm.

12. The production method according to claim 10 or 11, wherein, The temperature in step (2) is controlled at 25-40°C, the stirring rate is 50-100 rpm, and the stirring time is 10-30 min.

13. The method of making according to any one of claims 10-12, wherein, The temperature in step (3) is controlled at 25-40°C, the stirring rate is 50-70 rpm, and the stirring time is 15-20 h. Preferably, the filter in step (3) has a precision grade of 1-10 μm, preferably 2-5 μm.

14. Use of the temporary bonding adhesive according to any one of claims 1-9 in a wafer processing process. Preferably, the method of use comprises the steps of: providing a stack comprising a first substrate and a second substrate bonded together by a temporary bonding adhesive; heating the temporary bonding adhesive to cure the adhesive to form a bondline; and finally cleaning the wafer periphery of residual bondline using a cleaning agent.

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