Temporary bonding glue as well as preparation method and application thereof

Abstract

The invention provides a temporary bonding adhesive and a preparation method and application thereof, and the preparation raw materials of the temporary bonding adhesive comprise the following components by weight: 60-80% of an organic solvent; 20-35% of base resin; 0.1 to 1% of tackifying resin; 0.1%-1% of an antioxidant; and 0.1-1% of a wetting leveling agent. The temporary bonding adhesive provided by the invention has the properties of high hardness, smooth film surface, high adhesive strength, high chemical corrosion resistance and the like, and can be widely applied to wafer processing.

Description

Technical Field

[0001] The present invention belongs to the technical field of bonding adhesives, and relates to a temporary bonding adhesive and a preparation method and application thereof, and specifically relates to a temporary bonding adhesive for wafer-level packaging and a preparation method and application thereof. Background Art

[0002] Temporary bonding adhesive is the middle layer material that bonds the functional wafer and the temporary carrier together, and is also a key material in the wafer thinning process. From the perspective of temporary bonding adhesive materials, on the one hand, it is required to be able to tightly bond the wafer stack together so that the functional wafer is reliably supported and protected, and at the same time, it can withstand the processing conditions such as mechanical force, chemical corrosion and high temperature process in the subsequent process; on the other hand, it is required to be able to safely separate the functional wafer and the temporary carrier in a simple way after the processing is completed.

[0003] CN104204126A discloses an adhesive composition for wafer processing film, which is mainly used for temporarily fixing wafers during wafer processing (such as cutting or back grinding), or for protecting and reinforcing wafers. At the same time, the composition contains acrylic polymers and photosensitive gas generators, which can increase the wettability of wafers and avoid the bottom biting phenomenon of wafers. However, the above patent has the following defects and shortcomings: the temporary bonding composition is reactive, has a large shrinkage force during curing, has poor film surface uniformity, and is prone to local distortion during wafer bonding, resulting in weak chemical resistance of the prepared wafer.

[0004] Therefore, in the art, it is desired to develop a temporary bonding adhesive which has the characteristics of good chemical resistance, heat resistance, high bonding performance and easy cleaning. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a temporary bonding adhesive and its preparation method and application. The temporary bonding adhesive provided by the present invention has high hardness, smooth film surface, strong adhesion and chemical corrosion resistance, and can be widely used in wafer processing.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a temporary bonding adhesive, wherein the raw materials for preparing the temporary bonding adhesive include the following components in terms of weight percentage:

[0008]

[0009] The present invention adopts a compound of a specific base resin and a specific tackifying resin, 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 temperatures, but also has a strong film layer adhesion, so that the prepared wafer bonding pair can avoid immersion in high-polarity solvents and strong acid and alkali solutions, thereby improving the chemical liquid resistance of the wafer bonding pair.

[0010] The temporary bonding adhesive provided by the present invention has excellent mechanical strength, and there will be no uneven force phenomenon during the processing process. It can provide sufficient supporting force for the wafer and prevent the risk of wafer breakage during the grinding and polishing process.

[0011] In the present invention, the amount of organic solvent used in the preparation of the temporary bonding adhesive can be 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, etc., based on weight percentage.

[0012] In the present invention, the raw materials for preparing the temporary bonding adhesive can be calculated by weight percentage, and the amount of the base resin can be 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 35%, etc.

[0013] In the present invention, the raw materials for preparing the temporary bonding adhesive can be used in an amount of tackifying resin of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc., in terms of weight percentage.

[0014] In the present invention, the amount of antioxidant used in the preparation raw materials of the temporary bonding adhesive can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc., calculated by weight percentage.

[0015] In the present invention, the raw materials for preparing the temporary bonding adhesive can be used in an amount of the wetting and leveling agent of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc., in terms of weight percentage.

[0016] Preferably, the organic solvent comprises any one or a combination of at least two of cyclic hydrocarbon solvents (such as p-menthane, ethylcyclohexane, isopropylcyclohexane, etc.), ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether, preferably p-menthane / ethylene glycol butyl ether acetate, p-menthane / propylene glycol monomethyl ether acetate, ethylcyclohexane / ethylene glycol butyl ether acetate and propylene glycol monomethyl ether acetate / propylene glycol monomethyl ether.

[0017] Preferably, the base resin comprises a thermoplastic polymer resin, and the thermoplastic polymer resin comprises any one or a combination of at least two of polyketone resin (POK), polyphenylene ether resin (PPO), polyphenylene sulfone resin (PPSU), acrylic block copolymer (MAM), styrene-methyl methacrylate copolymer (MS), styrene-acrylonitrile resin (SAN) or polymethyl methacrylate resin (PMMA), preferably any one or a combination of at least two of MAM resin, MS resin and PPSU resin, and its molecular weight ranges from 50,000 to 200,000.

[0018] Preferably, the tackifying resin includes any one of poly-α-methylstyrene resin, styrene-C9 monomer copolymer, styrene-terpene resin, and dicyclopentadiene resin, or a combination of at least two thereof.

[0019] Preferably, the antioxidant includes any one of a hindered phenol antioxidant, a phosphite antioxidant or other antioxidants, or a combination of at least two thereof.

[0020] Preferably, the hindered phenol antioxidant includes antioxidant 1010 and / or antioxidant 1076.

[0021] Preferably, the phosphite antioxidant includes antioxidant 168 and / or antioxidant 626.

[0022] Preferably, the other antioxidants include any one of antioxidant 164, antioxidant TPP, and antioxidant DNP, or a combination of at least two of them.

[0023] Preferably, the wetting and leveling agent includes any one of an acrylate wetting and leveling agent, a silicone wetting and leveling agent, and other wetting and leveling agents, or a combination of at least two of them.

[0024] Preferably, the acrylic wetting and leveling agent includes BYK-361N and / or BYK-397.

[0025] Preferably, the silicone-based wetting and leveling agent includes BYK-323 and / or BYK-378.

[0026] Preferably, the other wetting and leveling agent includes a mixture of modified succinic acid and ester, such as BYK-3410.

[0027] The specific wetting and leveling agent selected in the present invention can effectively reduce the surface tension of the bonding adhesive, improve the spreading ability of the bonding adhesive on the surface of the substrate, so that the bonding adhesive can be evenly spin-coated on the surface of the wafer, avoid uneven thickness of the adhesive coating, and reduce the occurrence of bubbles and slippage during wafer bonding. The addition of the leveling agent ensures that the film surface is uniform and has no effect on the bonding performance of the film layer.

[0028] In a second aspect, the present invention provides a method for preparing the temporary bonding adhesive as described in the first aspect, the preparation method comprising the following steps:

[0029] (1) adding an organic solvent to a stirrer, starting stirring, and simultaneously starting a cooling water circulation system;

[0030] (2) adding a wetting and leveling agent and an antioxidant to the mixture in step (1) in sequence, and stirring until a clear and transparent liquid is formed;

[0031] (3) Adding the base resin and the tackifying resin to step (2) in sequence, stirring until a clear and transparent liquid is formed, and filtering to obtain the temporary bonding adhesive.

[0032] Preferably, the agitator in step (1) comprises a stirring kettle.

[0033] Preferably, the temperature of the cooling water circulation system in step (1) is controlled at 25-40°C, for example, 25°C, 30°C, 35°C, 40°C, etc.

[0034] Preferably, the stirring method in step (1) is mechanical stirring at a speed of 50 to 100 rpm (for example, 50 rpm, 60 rpm, 80 rpm, 100 rpm, etc.).

[0035] Preferably, the temperature of step (2) is controlled at 25-40°C, for example, 25°C, 30°C, 35°C, 40°C, etc., the stirring rate is 50-100rpm, for example, 50rpm, 60rpm, 80rpm, 100rpm, etc., and the stirring time is 10-30min, for example, 10min, 15min, 20min, 25min, 30min, etc.

[0036] Preferably, the temperature of step (3) is controlled at 25-40°C, for example, 25°C, 30°C, 35°C, 40°C, etc., the stirring rate is 50-70rpm, for example, 50rpm, 60rpm, 70rpm, etc., and the stirring time is 15-20h, for example, 15h, 16h, 18h, 20h, etc., preferably 15-16h.

[0037] Preferably, the accuracy grade of the filter element in step (3) is 1 to 10 μm, for example, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm, etc., preferably 2 to 5 μm.

[0038] In a third aspect, the present invention provides an application of the temporary bonding adhesive as described in the first aspect in a wafer processing technology.

[0039] Preferably, the method of application comprises the following steps:

[0040] Providing a stacked component including a first substrate and a second substrate bonded by the temporary bonding adhesive; heating the temporary bonding adhesive to solidify it to form an adhesive layer; and finally using a cleaning agent (such as Samcien Remover3) to clean the residual adhesive layer on the periphery of the wafer.

[0041] Exemplarily, the method for applying the temporary bonding adhesive in a wafer processing process comprises the following steps:

[0042] (a) Place a 12-inch wafer on a spin coater, start the vacuum system, fix the wafer with a suction cup, evenly pour 30-40 ml of the temporary bonding glue on the wafer, start spin coating, and set the spin coating parameters to first spin coating at 200-400 rpm for 30-40 seconds, and then spin coating at 1000-1500 rpm for 20-30 seconds;

[0043] (b) closing the vacuum chuck, removing the wafer coated with the temporary bonding glue, placing it in an oven at 90-100° C. for 5-10 minutes, preferably taking it out after 5 minutes; then placing it in an oven at 200-230° C. for 5-10 minutes, preferably taking it out after 5 minutes;

[0044] (c) In the same way, the laser release protective material was spin-coated on a 12-inch carrier. The spin-coating parameters were set to first spin-coat at 300-500 rpm for 5-10 s and then spin-coat at 1500-2000 rpm for 20-30 s. The baking conditions were set to 115-150° C. for 5-10 min in the first stage and 350-380° C. for 20-30 min in the second stage.

[0045] (d) After baking, the wafer adhesive surface and the carrier protective surface are attached to the surface of the wafer carrier, heated to 200-230°C, pressurized to 20-40 kN, bonded for 5-10 minutes (preferably 10 minutes), and cooled to room temperature to complete the temporary bonding of the wafer.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The present invention adopts a compound of a specific base resin and a specific tackifying resin, which not only improves the thermal stability of the temporary bonding adhesive, but also strengthens the adhesion of the film layer, thereby improving the chemical resistance of the wafer bonding pair.

[0048] (2) The temporary bonding adhesive provided by the present invention has excellent mechanical strength, and there will be no uneven force during the processing process. It can provide sufficient support for the wafer and prevent the risk of wafer breakage during the grinding and polishing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1This is a diagram showing the effect of the temporary bonding adhesive coating film surface provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] Unless otherwise specified, some raw material information involved in the following specific embodiments of the present invention is shown in Table 1 below. Other raw materials not shown are conventional materials in the art and can be purchased from commercial products.

[0052] Table 1

[0053]

[0054]

[0055] Examples 1 to 7 and Comparative Examples 1 to 4

[0056] Examples 1 to 7 and Comparative Examples 1 to 4 respectively provide a temporary bonding adhesive, and the raw materials and amounts thereof are shown in Table 2. In Table 2, the unit of the amount of each component is "kg".

[0057] Table 2

[0058]

[0059]

[0060] The preparation method of the temporary bonding adhesive provided in Examples 1 to 7 and Comparative Examples 1 to 4 comprises the following steps:

[0061] Add the organic solvent to a stirring kettle with a mechanical stirring and circulating water cooling system, start stirring and stir at a speed of 70 rpm; add the wetting and leveling agent and antioxidant while stirring and stir evenly; then add the base resin and tackifying resin to the stirring kettle, observe the temperature change in the kettle during this period, if the temperature rises too fast, adjust the circulating cooling water temperature, control the temperature at 40°C, and stir for 16 hours. When the material in the kettle becomes clear and transparent, stop stirring, and filter the material to obtain the temporary bonding adhesive.

[0062] Performance Test:

[0063] The testing methods of the physical and chemical properties involved in the above embodiments and comparative examples are as follows:

[0064] (1) Glue appearance and room temperature viscosity: Visually inspect the appearance of the glue and use a Brookfield viscometer to measure the room temperature viscosity of the bonding glue;

[0065] (2) Film surface condition and TTV: Use a microscope to observe whether there are wrinkles or glue missing on the edge of the coating, and use the American Corning Flatmaster 200 flatness tester to measure the uniformity of the film surface;

[0066] (3) Film hardness: Tested according to the test method provided in GB / T21838-2008 Instrumented indentation test for metal material hardness and material parameters, and the test sample is the coated wafer;

[0067] (4) High temperature rheological viscosity: The rheological viscosity of the rubber material was measured using an Anton Paar rheometer;

[0068] (5) Film adhesion: The adhesive was spin-coated on a 6-inch wafer and dried, and then the adhesive strength was measured using a BLD-200N electronic peel tester;

[0069] (6) Bonding condition: Visual inspection and microscope observation. The test sample is the wafer after bonding. Observe whether there are snowflake-shaped bubbles on the wafer after bonding.

[0070] (7) Resistance to corrosion by chemical solutions: The temporarily bonded wafers are immersed in a chemical solution (65% concentrated nitric acid). After soaking for a period of time (60°C, 1h), they are taken out, rinsed with clean water, and dried. Visually inspect the edges of the temporarily bonded wafers for any dissolution or whitening. If dissolution or whitening is found, it indicates corrosion that is visible to the naked eye. If no dissolution or whitening is found, it indicates no corrosion that is visible to the naked eye. In addition, a microscope is used to observe the depth of corrosion on the edges of the temporarily bonded wafers.

[0071] The temporary bonding adhesives provided in Examples 1 to 7 and Comparative Examples 1 to 4 were tested according to the above test method. The test results are shown in Table 3:

[0072] Table 3 Table 3

[0073]

[0074]

[0075] It can be seen from Table 3 that the temporary bonding adhesive prepared in Examples 1 to 7 has uniform film thickness, reliable bonding, no bonding defects and good chemical resistance when used in wafer processing. Figure 1 As shown, it can be seen that the coating film edge uniformity is excellent.

[0076] When the temporary bonding adhesive provided in Comparative Examples 1 to 2 is used for wafer processing, the coating uniformity is poor and the adhesion is poor, resulting in the wafer bonding having a weak resistance to chemical solutions.

[0077] When the temporary bonding glue provided in Comparative Example 3 is used for wafer processing, the coating is uniform and excellent, with good adhesion and good resistance to chemical solutions. However, the viscosity of the prepared bonding glue at room temperature is too large, which is not conducive to construction; the prepared film layer has low hardness and cannot provide sufficient support for the wafer, resulting in the risk of wafer breakage during the grinding and thinning process; and the high temperature rheological viscosity requires an extremely high bonding process to complete wafer bonding, which consumes a lot of energy.

[0078] When the temporary bonding glue provided in Comparative Example 4 is used for wafer processing, the wafer bonding has weak resistance to chemical solutions due to the weak adhesion of the film layer, and the insufficient adhesion of the coating may cause the risk of wafer slippage during the grinding and polishing process, affecting the product yield.

[0079] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the temporary bonding adhesive of the present invention and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A temporary bonding adhesive, characterized in that: The raw materials for preparing the temporary bonding adhesive include the following components by weight percentage:

2. The temporary bonding adhesive according to claim 1, characterized in that: The organic solvent includes any one of cyclic hydrocarbon solvents, ethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether, or a combination of at least two thereof; Preferably, the cyclic hydrocarbon solvent includes any one of p-mentane, ethylcyclohexane, isopropylcyclohexane, or a combination of at least two thereof.

3. The temporary bonding adhesive according to claim 1 or 2, characterized in that: The base resin includes a thermoplastic polymer resin, and the thermoplastic polymer resin includes any one of polyketone resin, polyphenylene ether resin, polyphenylene sulfone resin, acrylic acid block copolymer, styrene-methyl methacrylate copolymer, styrene-acrylonitrile resin or polymethyl methacrylate resin, or a combination of at least two thereof; Preferably, the tackifying resin includes any one of poly-α-methylstyrene resin, styrene-C9 monomer copolymer, styrene-terpene resin, and dicyclopentadiene resin, or a combination of at least two thereof.

4. The temporary bonding adhesive according to any one of claims 1 to 3, characterized in that: The antioxidant includes any one of a hindered phenol antioxidant, a phosphite antioxidant or other antioxidants, or a combination of at least two thereof.

5. The temporary bonding adhesive according to claim 4, characterized in that: The hindered phenol antioxidant includes antioxidant 1010 and / or antioxidant 1076; Preferably, the phosphite antioxidant includes antioxidant 168 and / or antioxidant 626; Preferably, the other antioxidants include any one of antioxidant 164, antioxidant TPP, and antioxidant DNP, or a combination of at least two of them.

6. The temporary bonding adhesive according to any one of claims 1 to 5, characterized in that: The wetting and leveling agent includes any one of an acrylate wetting and leveling agent, a silicone wetting and leveling agent, and other wetting and leveling agents, or a combination of at least two of them.

7. The temporary bonding adhesive according to claim 6, characterized in that: The acrylic 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 comprises a mixture of modified succinic acid and ester.

8. A method for preparing a temporary bonding adhesive as claimed in any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) adding an organic solvent to a stirrer, starting stirring, and simultaneously starting a cooling water circulation system; (2) adding a wetting and leveling agent and an antioxidant to the mixture in step (1) and stirring until a clear and transparent liquid is formed; (3) adding the base resin and the tackifying resin to step (2), stirring until a clear and transparent liquid is formed, and filtering to obtain the temporary bonding adhesive.

9. The preparation method according to claim 8, characterized in that: The agitator in step (1) comprises a stirring kettle; Preferably, the temperature of the cooling water circulation system in step (1) is controlled at 25-40°C; Preferably, the stirring method in step (1) is mechanical stirring at a speed of 50 to 100 rpm; Preferably, the temperature of step (2) is controlled at 25-40° C., the stirring rate is 50-100 rpm, and the stirring time is 10-30 min; Preferably, the temperature of 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 accuracy grade of the filter element in step (3) is 1 to 10 μm, preferably 2 to 5 μm.

10. Use of the temporary bonding adhesive according to any one of claims 1 to 7 in a wafer processing process; Preferably, the method of application comprises the following steps: providing a laminate comprising a first substrate and a second substrate bonded by the temporary bonding adhesive; The temporary bonding adhesive is heated to solidify it to form an adhesive layer; and finally, a cleaning agent is used to clean the adhesive layer remaining on the periphery of the wafer.

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