Organic silicon capable of being de-bonded by laser as well as preparation method and application of organic silicon

Abstract

The invention provides organic silicon capable of being de-bonded by laser as well as a preparation method and application of the organic silicon. The organic silicon comprises the following components: an organic solvent, vinyl raw rubber, vinyl silicone oil, hydrogen-containing silicone oil, a light-absorbing filler, a platinum catalyst and an inhibitor. The invention provides an organic silicon bonding adhesive which is strong in bonding force, strong in chemical corrosion resistance and smooth in film surface. The organic silicon bonding adhesive can be used for smoothly and firmly adhering a wafer to a carrier with certain mechanical strength in a back grinding process; the temporary bonding glue can be separated from the supporting carrier in a laser irradiation mode, the bonded carrier does not need to be additionally spin-coated with a laser release layer material, the processing time is shortened, and meanwhile the problems that the bonding force between the temporary bonding glue and the laser release material layer is not uniform and unstable and the like are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wafer production and processing, and particularly relates to a laser-debondable silicone, a preparation method thereof, and an application thereof. Background Art

[0002] In the field of semiconductor technology, in order to improve the electrical performance of a chip while maintaining a certain heat dissipation efficiency of the chip, it is usually necessary to grind the back surface (Back Grinding) of the wafer before packaging to reduce the thickness of the wafer. The smooth progress of the back grinding process depends on a temporary bonding technology to reliably adhere the wafer to be thinned to a glass carrier with a certain mechanical strength. After thinning, the thinned wafer is separated from the glass carrier by a certain method.

[0003] CN112341985A discloses a temporary adhesive composition, which comprises a polyfunctional crosslinking agent, a polymer, and a solvent. The polyfunctional crosslinking agent comprises a compound containing at least two functional groups selected from blocked isocyanate groups, vinyl ether groups, and hydrocarbon oxy methylene groups, and each blocked isocyanate group is an isocyanate group protected by a blocking agent. The polymer has a functional group capable of reacting with the polyfunctional crosslinking agent. Thus, the temporary adhesive composition of the present invention can simultaneously have excellent hot pressing properties and solvent resistance through different components and formulations, which is beneficial to the temporary bonding / stripping technology and can be applied to semiconductor wafer packaging.

[0004] US20210040365A1 discloses a temporary adhesive composition. The temporary adhesive composition includes a multifunctional crosslinking agent, a polymer, and a solvent. The polyfunctional crosslinking agent includes a compound containing at least two functional groups selected from blocked isocyanate groups, vinyl ether groups, and alkoxyhydrocarbon groups. Each blocked isocyanate group is an isocyanate group protected by a blocking agent. The polymer has a functional group that reacts with the polyfunctional crosslinking agent.

[0005] Although many materials for temporary bonding of wafers have been disclosed in the prior art, if these materials have a large adhesive force, it will cause mechanical debonding to be impossible, and there are problems such as incomplete decomposition during the debonding process, which adhere to the temporary bonding adhesive layer and affect the next stripping and cleaning experiments. Therefore, there is an urgent need to provide a material that can completely separate the adhesive layer and the support plate after debonding to meet the application requirements. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a laser-debondable silicone and its preparation method and application. The present invention provides a silicone bonding adhesive with strong adhesion, strong chemical corrosion resistance, and smooth film surface. The silicone bonding adhesive can firmly adhere the wafer to a carrier with a certain mechanical strength during the back grinding process, and it can be separated from the support carrier by laser irradiation, without the need to spin-coat an additional laser release layer material on the bonded carrier, shortening the processing time and avoiding problems such as uneven and unstable bonding force between the temporary bonding adhesive and the laser release material layer.

[0007] To achieve the purpose of this invention, the following technical solutions are adopted:

[0008] In the first aspect, the present invention provides a laser-debondable silicone. The components of the silicone include, by mass percentage:

[0009]

[0010] By screening suitable light-absorbing fillers and incorporating them into the silicone material system through copolymerization and other methods, a single-layer temporary bonding material capable of laser debonding is prepared. This material bonds the glass support plate and the wafer substrate and can be debonded under a laser in the wavelength range of 330 - 360 nm, separating from the glass support plate without the need to spin-coat an additional laser release layer material on the bonded glass substrate, shortening the processing time and avoiding problems such as uneven and unstable bonding force between the temporary bonding adhesive and the laser release material layer.

[0011] The mass percentage of the organic solvent in the silicone components of the present invention can be 51%, 53%, 55%, 58%, 60%, 62%, 65%, 67%, or 69%, etc.;

[0012] The mass percentage of the vinyl raw rubber can be 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, or 19%, etc.;

[0013] The mass percentage of the vinyl silicone oil can be 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, or 19%, etc.;

[0014] The mass percentage of the hydrogen-containing silicone oil can be 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, or 24%, etc.;

[0015] The mass percentage of the light-absorbing filler can be 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or 4.5%, etc.;

[0016] The mass percentage content of the platinum catalyst can be 0.5 ppm, 0.6 ppm, 0.7 ppm, 0.8 ppm, 0.9 ppm, 1 ppm, etc.

[0017] The mass percentage content of the inhibitor can be 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3% or 1.4%, etc.

[0018] Preferably, the organic solvent is one or more of cyclohexane, n-hexane, ethylcyclohexane, propylene glycol methyl ether acetate (PMA), propylene glycol methyl ether (PM) or cyclohexanone.

[0019] Preferably, the molecular weight of the vinyl raw rubber is 400,000 - 700,000, and can be, for example, 450,000, 500,000, 550,000, 600,000 or 650,000, etc.

[0020] Preferably, the vinyl content in the vinyl raw rubber is 0.03 - 3%, and can be, for example, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25% or 0.28%, etc.

[0021] Preferably, the vinyl raw rubber includes any one or a combination of at least two of methyl-capped methyl vinyl raw rubber, vinyl-capped methyl vinyl raw rubber, methyl vinyl phenyl raw rubber or methyl vinyl trifluoropropyl raw rubber.

[0022] Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.1 - 1.2 mmol / g, and can be, for example, 0.2 mmol / g, 0.3 mmol / g, 0.4 mmol / g, 0.5 mmol / g, 0.6 mmol / g, 0.7 mmol / g, 0.8 mmol / g, 0.9 mmol / g, 1 mmol / g or 1.1 mmol / g, etc.

[0023] Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.5 - 1 mmol / g.

[0024] Preferably, the inhibitor includes any one or a combination of at least two of 3-methyl-1-pentyn-3-ol, tetramethyltetravinylcyclotetrasiloxane, ethynylcyclohexanol, tetramethylethylenediamine, tetramethylbutynol, methylbutynol, diallyl maleate or 2-methyl-3-butyn-2-ol.

[0025] Preferably, the light-absorbing compound includes any one or a combination of at least two of graphene oxide, azobenzene, carbon black or CNT.

[0026] Preferably, the light-absorbing compound is a combination of graphene oxide and azobenzene.

[0027] Preferably, the mass ratio of graphene oxide to azobenzene is 1:(5 - 15), for example, it can be 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13 or 1:14, etc.

[0028] Preferably, the viscosity of the vinyl silicone oil is 200 - 7000 mPa·s, for example, it can be 500 mPa·s, 800 mPa·s, 1000 mPa·s, 2000 mPa·s, 3000 mPa·s, 4000 mPa·s, 5000 mPa·s or 6000 mPa·s, etc.

[0029] Preferably, the vinyl content in the vinyl silicone oil is 0.5 - 0.7%, for example, it can be 0.51%, 0.53%, 0.55%, 0.58%, 0.6%, 0.63%, 0.65%, 0.67% or 0.69%, etc.

[0030] Preferably, the vinyl silicone oil includes any one or a combination of at least two of RH - Vi1321, RH - Vi1322, RH - Vi1324, RH - Vi1325 or RH - Vi1360.

[0031] Preferably, the vinyl silicone oil is RH - Vi1360.

[0032] Specific point values within the above numerical ranges can all be selected, and will not be elaborated one by one here.

[0033] In a second aspect, the present invention provides a preparation method of the laser - debondable silicone according to the first aspect, and the preparation method includes:

[0034] (1) Mix and react vinyl silicone oil, vinyl raw rubber, light - absorbing filler and organic solvent;

[0035] (2) Add an inhibitor and hydrogen - containing silicone oil in sequence, and obtain a glue solution after mixing;

[0036] (3) Add a platinum catalyst to the glue solution, filter after reaction, and obtain the laser - debondable silicone.

[0037] Preferably, the mixing in step (1) is carried out by stirring, and the stirring speed is 100 - 300 rpm, for example, it can be 120 rpm, 150 rpm, 180 rpm, 200 rpm, 220 rpm, 250 rpm or 280 rpm, etc.

[0038] Preferably, the temperature of the mixing in step (1) is 75 - 85°C, for example, it can be 76°C, 78°C, 80°C, 82°C or 84°C, etc.

[0039] Preferably, the reaction in step (3) is carried out under stirring, and the rotation speed of the stirring is 100 - 400 rpm, for example, it can be 120 rpm, 150 rpm, 180 rpm, 200 rpm, 220 rpm, 250 rpm, 280 rpm, 300 rpm, 320 rpm, 350 rpm or 380 rpm, etc.

[0040] Preferably, the reaction time in step (3) is 4 - 8 h, for example, it can be 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h or 7.5 h, etc.

[0041] Preferably, the precision of the filter element used for filtration in step (3) is 5 - 10 μm, for example, it can be 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm or 9.5 μm, etc.

[0042] Specific point values within the above numerical ranges can all be selected, and will not be elaborated one by one here.

[0043] In a third aspect, the present invention provides an application of the laser - debondable silicone as described in the first aspect in wafer processing.

[0044] Preferably, the application method of the laser - debondable silicone in the wafer processing technology includes the following steps:

[0045] (a) Place a 12 - inch wafer on a spin coater, turn on the vacuum pumping system, fix the wafer with a chuck, uniformly pour 40 - 50 ml of silicone on the wafer, turn on the spin coating, and set the spin coating rate to 400 - 800 rpm / 60 - 90 sec or 1500 - 2000 rpm / 2 - 5 sec;

[0046] (b) Turn off the vacuum chuck, remove the wafer coated with silicone, and place it in an oven at 60 - 90 °C for baking for 4 - 8 min, preferably 5 min;

[0047] (c) After baking, the coated surface of the wafer and the glass sheet are attached to the surface of the carrier stage, evacuate, heat to 180 - 220 °C, apply a pressure of 0.1 - 0.2 KN, bond for 5 - 10 min (preferably 10 min), and complete the temporary bonding of the wafer after cooling to room temperature.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] The present invention prepares a single-layer temporary bonding material capable of laser debonding by screening suitable light-absorbing fillers and incorporating them into the silicone material system through copolymerization or other means. This material bonds the glass support plate and the wafer substrate and can be debonded under a laser in the wavelength range of 330 - 360 nm, separating from the glass support plate. There is no need to spin-coat an additional laser release layer material on the bonded glass substrate, which shortens the processing time and also avoids problems such as uneven and unstable adhesion between the temporary bonding adhesive and the laser release material layer. Detailed implementation manners

[0050] The technical solution of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0051] Example 1

[0052] This example provides a laser-debondable silicone. The components of the silicone, by mass percentage, include:

[0053] Vinyl raw rubber (Dongjue 110-7, molecular weight 500,000, vinyl content 2%) 15%, vinyl silicone oil (Runhe RH-Vi1360, viscosity 2000 mPa·s) 15%, hydrogen-containing silicone oil (Xibao MH750, hydrogen content 0.75 mmol / g) 20%, light-absorbing filler (graphene oxide and azobenzene with a mass ratio of 1:10) 3%, platinum catalyst 0.8 ppm, tetramethylethylenediamine 1%, and the balance is cyclohexane.

[0054] The preparation method of the silicone includes the following steps:

[0055] (1) Mix and react vinyl silicone oil, vinyl raw rubber, light-absorbing filler and organic solvent at a temperature of 80 °C and a rotation speed of 200 prm.

[0056] (2) Add an inhibitor and hydrogen-containing silicone oil in sequence, and obtain a glue solution after mixing.

[0057] (3) Add a platinum catalyst to the glue solution, react at a rotation speed of 300 rpm for 5 h until a clear solution is obtained, and then filter with a filter element with a precision of 8 μm to obtain the laser-debondable silicone.

[0058] Example 2

[0059] This example provides a laser-debondable silicone. The components of the silicone, by mass percentage, include:

[0060] 10% of vinyl raw rubber (Dow 0701, molecular weight 400,000, vinyl content 1%), 20% of vinyl silicone oil (Runhe RH-Vi1325, viscosity 5000 mPa·s), 15% of hydrogen-containing silicone oil (Xibao MH500, hydrogen content 0.5 mmol / g), 5% of light-absorbing filler (graphene oxide and azobenzene with a mass ratio of 1:15), 1.0 ppm of platinum catalyst, and 0.5% of tetramethylethylenediamine. The balance is propylene glycol methyl ether acetate.

[0061] The preparation method of the silicone includes the following steps:

[0062] (1) Mix and react vinyl silicone oil, vinyl raw rubber, light-absorbing filler and organic solvent at a temperature of 75 °C and a rotation speed of 100 prm;

[0063] (2) Add inhibitor and hydrogen-containing silicone oil in sequence, and obtain a glue solution after mixing;

[0064] (3) Add platinum catalyst to the glue solution, react at a rotation speed of 400 rpm for 4 h to a clear solution, and then filter with a filter element with a precision of 10 μm to obtain the laser-debondable silicone.

[0065] Example 3

[0066] This example provides a laser-debondable silicone, and the components of the silicone include by mass percentage:

[0067] 20% of vinyl raw rubber (Dow 0730, molecular weight 600,000, vinyl content 3%), 10% of vinyl silicone oil (Runhe RH-Vi1324, viscosity 800 mPa·s), 25% of hydrogen-containing silicone oil (Xibao MH180, hydrogen content 1.8 mmol / g), 1% of light-absorbing filler (graphene oxide and azobenzene with a mass ratio of 1:5), 0.5 ppm of platinum catalyst, and 1.5% of tetramethylethylenediamine. The balance is cyclohexanone.

[0068] The preparation method of the silicone includes the following steps:

[0069] (1) Mix and react vinyl silicone oil, vinyl raw rubber, light-absorbing filler and organic solvent at a temperature of 85 °C and a rotation speed of 300 prm;

[0070] (2) Add inhibitor and hydrogen-containing silicone oil in sequence, and obtain a glue solution after mixing;

[0071] (3) Add platinum catalyst to the glue solution, react at a rotation speed of 100 rpm for 8 h to a clear solution, and then filter with a filter element with a precision of 5 μm to obtain the laser-debondable silicone.

[0072] Example 4

[0073] This example provides a laser-debondable silicone. The difference between this silicone and that of Example 1 is that the light-absorbing filler is only graphene oxide, and the addition amount of the light-absorbing filler remains unchanged. The other components are the same as those of Example 1, and the preparation method refers to Example 1.

[0074] Example 5

[0075] This example provides a laser-debondable silicone. The difference between this silicone and that of Example 1 is that the light-absorbing filler is only azobenzene, and the addition amount of the light-absorbing filler remains unchanged. The other components are the same as those of Example 1, and the preparation method refers to Example 1.

[0076] Example 6

[0077] This example provides a laser-debondable silicone. The difference between this silicone and that of Example 1 is that the hydrogen content of the hydrogen-containing silicone oil is 0.1 mmol / g (Runhe RH-H222-3), and the addition amount of the hydrogen-containing silicone oil remains unchanged. The other components are the same as those of Example 1, and the preparation method refers to Example 1.

[0078] Example 7

[0079] This example provides a laser-debondable silicone. The difference between this silicone and that of Example 1 is that the hydrogen content of the hydrogen-containing silicone oil is 1.2 mmol / g (Runhe RH-H512), and the addition amount of the hydrogen-containing silicone oil remains unchanged. The other components are the same as those of Example 1, and the preparation method refers to Example 1.

[0080] Comparative Example 1

[0081] This comparative example provides a laser-debondable silicone. The difference between this silicone and that of Example 1 is that the light-absorbing filler is not included in the components, and the reduced amount is made up by the organic solvent. The other components are the same as those of Example 1, and the preparation method refers to Example 1.

[0082] Comparative Example 2

[0083] This comparative example provides a laser-debondable silicone. The difference between this silicone and that of Example 1 is that the mass percentage content of the light-absorbing filler in the components is 6%, and the increased amount is obtained by reducing the organic solvent. The other components are the same as those of Example 1, and the preparation method refers to Example 1.

[0084] Comparative Example 3

[0085] This comparative example provides a laser-debondable silicone. The difference between this silicone and that of Example 1 is that the mass percentage content of the light-absorbing filler in the components is 0.5%, and the increased amount is obtained by reducing the organic solvent. The other components are the same as those of Example 1, and the preparation method refers to Example 1.

[0086] Test Example

[0087] Performance tests were carried out on the silicone rubbers provided in Examples 1-7 and Comparative Examples 1-3, and the test methods are as follows:

[0088] (1) Coating uniformity: The dried silicon wafer coated with silicone rubber was prepared by the application method of silicone rubber in the wafer processing technology. The thickness of the temporary bonding adhesive film on the wafer was measured by the nine-point method, and the difference between the maximum film thickness and the minimum film thickness was used as the film thickness TTV. The film thickness TTV is preferably less than 1 μm;

[0089] (2) Adhesion strength: The adhesive was spin-coated on a 12-inch wafer, and after drying, the adhesion of the adhesive was measured using a BLD-200N electronic peeling tester;

[0090] (3) Bonding pair condition: The center and edge of the bonding pair were observed under a microscope, and it was preferred that there were no defects such as chipping and snowflake-like bubbles;

[0091] (4) Debonding condition: The bonded wafer was debonded using a laser in the 330-360 nm wavelength band, and it was observed whether the wafer and the silicone rubber were debonded.

[0092] (5) Debonding pair cleaning effect: The debonded wafer was immersed in a cleaning agent, taken out after ultrasonic cleaning for 10 min, rinsed, dried, and the surface of the wafer was observed under a microscope. It was preferred that there was no stain residue.

[0093] (6) The temperature change of the sample was directly measured using a laser calorimetric absorption measuring instrument such as (LC-2000), and the laser absorption rate was calculated through the heat balance equation.

[0094] The performance test results are shown in Table 1.

[0095] Table 1

[0096]

[0097]

[0098] If the test result is excellent or the effect is good, the evaluation is "○"; if the test result has defects or the effect is poor, the evaluation is "×".

[0099] As can be seen from Table 1, the silicone rubber prepared in Examples 1-3 of the present invention can be debonded under a laser in the 330-360 nm wavelength band when used in wafer processing, and has uniform film thickness, reliable adhesion, no defects in bonding, good heat resistance, and can be cleaned cleanly with a cleaning agent without residual glue.

[0100] As can be seen from Examples 4 and 5, when the light-absorbing material is not the combination of graphene oxide and azobenzene selected in the present invention, the material cannot be debonded under a laser;

[0101] As can be seen from Examples 6 and 7, when the hydrogen content of the hydrogen-containing silicone oil is not within the defined range of the present invention, it will affect the bonding strength of the material.

[0102] As can be seen from Comparative Example 1, when the components of the silicone do not contain a light-absorbing material, the material cannot be debonded under laser light;

[0103] As can be seen from Comparative Examples 2 and 3, the amount of the light-absorbing material also affects the debonding effect of the material.

[0104] The applicant declares that the present invention uses the above examples to illustrate a laser-debondable silicone and its preparation method and application of the present invention, but the present invention is not limited to the above examples, that is, it does not mean that the present invention must rely on the above examples to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

[0105] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0106] In addition, it should be noted that in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

Claims

1. A laser debondable organosilicon, characterized in that: The components of the organosilicon include, by mass percentage:

2. The laser debondable silicone according to claim 1, characterized in that: The organic solvent is one or more of cyclohexane, n-hexane, ethylcyclohexane, propylene glycol methyl ether acetate, propylene glycol methyl ether or cyclohexanone.

3. The laser debondable organic silicon according to claim 1 or 2, characterized in that: The molecular weight of the vinyl rubber is 400,000 to 700,000; Preferably, the vinyl content in the vinyl raw rubber is 0.03-3%; Preferably, the vinyl raw rubber includes any one of methyl-terminated methyl vinyl raw rubber, vinyl-terminated methyl vinyl raw rubber, methyl vinyl phenyl raw rubber or methyl vinyl trifluoropropyl raw rubber, or a combination of at least two thereof.

4. The laser debondable silicone according to any one of claims 1 to 3, characterized in that: The hydrogen content of the hydrogen-containing silicone oil is 0.1-1.2 mmol / g; Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.5-1 mmol / g; Preferably, the inhibitor comprises any one of 3-methyl-1-pentyn-3-ol, tetramethyltetravinylcyclotetrasiloxane, ethynylcyclohexanol, tetramethylethylenediamine, tetramethylbutynol, methylbutynol, diallyl maleate or 2-methyl-3-butyn-2-ol, or a combination of at least two thereof.

5. The laser debondable silicone according to any one of claims 1 to 4, characterized in that: The light absorbing compound includes any one or a combination of at least two of graphene oxide, azobenzene, carbon black or CNT; Preferably, the light absorbing compound is a combination of graphene oxide and azobenzene.

6. The laser debondable silicone according to any one of claims 1 to 5, characterized in that: The viscosity of the vinyl silicone oil is 200-7000 mPa·s; Preferably, the vinyl content in the vinyl silicone oil is 0.5-0.7%.

7. A method for preparing laser debondable silicone according to any one of claims 1 to 6, characterized in that: The preparation method comprises: (1) mixing vinyl silicone oil, vinyl rubber, light-absorbing filler and organic solvent for reaction; (2) adding an inhibitor and hydrogen-containing silicone oil in sequence, and mixing them to obtain a glue solution; (3) Adding a platinum catalyst to the glue solution, filtering after the reaction, and obtaining the laser debondable organic silicon.

8. The preparation method according to claim 7, characterized in that: The mixing in step (1) is carried out by stirring at a speed of 100-300 rpm; Preferably, the mixing temperature in step (1) is 75-85°C.

9. The preparation method according to claim 7 or 8, characterized in that: The reaction in step (3) is carried out under stirring at a speed of 100-400 rpm; Preferably, the reaction time in step (3) is 4-8h; Preferably, the accuracy of the filter element used for filtration in step (3) is 5-10 μm.

10. Use of the laser debondable organosilicon according to any one of claims 1 to 6 in wafer processing.

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