Organosilicone adhesive applied to MEMS chip bonding and preparation method thereof

Abstract

The invention relates to an organic silicon adhesive applied to MEMS chip bonding and a preparation method thereof. The organic silicon adhesive comprises the following components in parts by weight: 5%-25% of vinyl silicone oil, 50%-70% of VQM, 8%-20% of hydrogen-containing silicone oil, 0.50%-1.00% of a silane coupling agent, 0.50%-1.00% of a catalyst, 0.10%-0.50% of an inhibitor, 0.5%-2.00% of pigment and 7%-15% of filler. Compared with the prior art, the adhesive can bear relatively high external shear thrust, the stress generated by the adhesive layer is low, the adhesive force is strong, and the requirement of the bottom adhesive property of the MEMS Die is met.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to an organic silicone adhesive used for bonding MEMS chips. Background Art

[0002] With the rapid development of industries such as consumer electronics and new energy vehicles, the demand for MEMS sensors in China is growing rapidly. The full name of MEMS is Micro-ElectroMechanical System. MEMS is an intelligent system manufactured using microelectronics and micromachining technology. MEMS devices mainly use standard molding packaging. The packaging process mainly includes: bonding the chip to the substrate; using gold wire or copper wire to achieve electrical connection between the chip and the package lead; spraying compound materials for protection or sealing. The microstructure of the MEMS Die determines that the external force it can withstand is very low, that is, the stress of the Dieattach adhesive is required to be as low as possible, while meeting the bonding strength of the bottom of the MEMS Die. At the same time, the Young's modulus of the MEMS bonding material is required to be as large as possible, so that the chip and the substrate are not easily deformed. The standard operating temperature of MEMS is -40 to 100°C. Therefore, at the operating temperature of MEMS: the stress of Silicone Die attach adhesive is much lower than that of Epoxy Die attach adhesive, which is the best choice for MEMS Die attach adhesive materials.

[0003] The microstructure of MEMS die determines that the external force it can withstand is very low, which requires the die attach adhesive stress to be as low as possible while meeting the bonding strength of the bottom of the MEMS die. Silicone adhesives are selected as MEMS bonding materials because of their excellent weather resistance, excellent high and low temperature resistance, good viscosity and hydrophobicity, excellent electrical properties and chemical corrosion resistance. The stress of silicone adhesives is much lower than that of epoxy die attach adhesives, but the bonding strength of silicone adhesives is generally relatively small. The bonding strength is usually related to the body strength of the adhesive after curing and the bonding aid.

[0004] Patent application CN202211607270.X discloses a thermally conductive insulating silica gel for high-strength semiconductor packaging, which includes the following components by weight: 6-10 parts of base material, 5.6-20 parts of active diluent, 0.5-5 parts of hydrogen-containing silicone oil, 0.1-2 parts of reinforcing agent, 1-5 parts of adhesive, 0.05-1 part of catalyst, 0.01-1 part of inhibitor, 250-400 parts of thermally conductive filler, and the obtained thermally conductive insulating silica gel has good thermal conductivity and strength, but the thermally conductive filler in the thermally conductive insulating glue has a particle size of 50um spherical boron nitride, which limits the thickness of the glue layer. When fixing a MEMS chip with a side length of less than 1mm, the thickness of the glue layer is 20-30um, which cannot be met. At the same time, the addition of thermally conductive fillers will increase the density of the glue, making it difficult to lightweight electronic products. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide an organic silicone adhesive used for MEMS chip bonding and its preparation method, which can withstand high external shear thrust, has low stress generated by the adhesive layer, has strong bonding force, and meets the requirements of MEMS chip bottom bonding performance.

[0006] The object of the present invention can be achieved by the following technical solution: An organic silicone adhesive used for bonding MEMS chips, comprising the following components in parts by weight:

[0007] Vinyl silicone oil 5% to 25%,

[0008] VQM 50%~70%,

[0009] Silicone oil containing 8% to 20% hydrogen,

[0010] Silane coupling agent 0.50%~1.00%,

[0011] Catalyst 0.50%~1.00%,

[0012] Inhibitor 0.10%~0.50%,

[0013] Pigment 0.5%~2.00%,

[0014] Filler 7%~15%.

[0015] Furthermore, the vinyl silicone oil comprises one or more low-volatility dimethyl polysiloxanes containing at least two vinyl groups per molecule, with a viscosity of 500 to 5000 mPa·s and a vinyl content of 0.05 to 0.15 mmol / g.

[0016] Furthermore, the VQM is a mixture of vinyl MQ resin and vinyl silicone oil, with a viscosity of 1000 to 30000 mPa·s and a vinyl content of 0.18 to 0.45 mmol / g, wherein the content of the vinyl MQ resin is 20 to 45 wt%.

[0017] Furthermore, the hydrogen-containing silicone oil includes one or more low-volatile polydimethyl silicone oils containing two or more Si-H groups in at least each molecule, the Si-H groups are located on the molecular chain side and the chain end, or only on the chain side, the viscosity is 20 to 500 mPa·s, and the hydrogen content is 1.1 to 16 mmol / g.

[0018] Furthermore, the silane coupling agent includes γ-methacryloxypropyltrimethoxysilane KH570, γ-glycidyloxypropyltrimethoxysilane KH560 or vinyltrimethoxysilane.

[0019] Furthermore, the catalyst is an organic metal compound or organic metal chelate containing chloroplatinic acid or platinum or palladium, preferably a Custer platinum catalyst.

[0020] Furthermore, the inhibitor includes one or more of 1-ethynyl-1-cyclohexanol, alkynyl alcohol derivatives, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, bis(2-ethylhexyl) maleate or maleic acid derivatives.

[0021] Furthermore, the pigment is iron black or carbon black.

[0022] Furthermore, the filler is gas phase carbon black or precipitated white carbon black.

[0023] The present invention also provides a method for preparing an organic silicone adhesive used for bonding MEMS chips, comprising adding vinyl silicone oil, VQM, hydrogen-containing silicone oil, silane coupling agent, inhibitor, and pigment into a container, stirring evenly, and evacuating the container; adding filler, stirring evenly, and evacuating the container; adding a catalyst, stirring evenly, and evacuating the container to obtain a semi-finished product A; and uniformly dispersing the semi-finished product A, filtering, and obtaining a final product.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention adopts low-volatility dimethyl polysiloxane raw material, which is green and environmentally friendly and will not cause pollution to other components.

[0026] (2) Use a mixture of vinyl MQ resin and vinyl silicone oil VQM in a specific dosage ratio to produce a synergistic effect with dimethyl polysiloxane and hydrogen-containing silicone oil; the organic part in the vinyl MQ resin can improve its compatibility with silicone rubber, and the siloxane chain energy can improve the mechanical strength, cohesive strength, peel strength and high temperature resistance of silicone rubber, playing a reinforcing role. Addition-type vulcanized silicone rubber is mainly composed of vinyl-containing raw rubber, reinforcing filler, hydrogen-containing silicone oil crosslinker and platinum catalyst. Under the action of platinum catalyst, the vinyl-containing MQ resin can produce chemical bonding through a silane-hydrogen addition reaction with the SiH crosslinker, thereby forming a three-dimensional network structure to play a reinforcing role, improve the body strength of the adhesive after curing to improve the bonding of MEMS chips, and solve the problem of low bonding strength of silicone adhesives.

[0027] (3) The catalyst used in the present invention is an organic metal compound or organic metal chelate containing chloroplatinic acid or platinum or palladium. First, the tetravalent Pt ion is reduced to low-valent Pt by hydrosilane or other compounds and then undergoes three basic steps to form a catalytic cycle. The first step is the oxidative addition of hydrosilane to the Pt-olefin complex; the second step is to insert the coordinated olefin into Pt-H; the third step is reduction elimination to form a hydrosilation product. The combination of white carbon black adjusts the rheological properties and reinforcement effect, meets the process requirements, and also allows the glue to climb to a certain extent to improve the adhesion of MEMSDie.

[0028] (4) The stress of silicone die attach adhesive is much lower than that of epoxy die attach adhesive, making it the best choice for MEMS die attach adhesive materials. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to specific embodiments.

[0030] The raw materials used in the present invention are all commercially available products unless otherwise specified. For example, the raw materials used in the following examples and comparative examples are

[0031] The vinyl silicone oil is Andisil VS series vinyl-terminated polydimethylsiloxane produced by Ambient Special Silicone Co., Ltd.

[0032] VQM uses the VQM900 series of vinyl QM resin products from Evonik Specialty Chemicals Co., Ltd.

[0033] The hydrogen-containing silicone oil is selected from the Andisil XL series products of Ambient Special Silicone Co., Ltd.

[0034] The silane coupling agent used is KBM-403 and KBM-503 produced by Shin-Etsu Chemical Co., Ltd.

[0035] The inhibitor used was 1-ethynyl cyclohexanol produced by Shanghai Aladdin Biochemical Technology Co., Ltd.

[0036] The catalyst used is 2000ppm Karstedt platinum catalyst produced by Dongguan Aokai New Materials Co., Ltd.

[0037] The fillers used are Evonik Degussa R974 and R2800 products.

[0038] The pigment used was Mitsubishi Carbon Black MA100.

[0039] Example 1

[0040] The composition of the components in an organic silicone adhesive used for bonding MEMS chips is (by weight percentage):

[0041]

[0042] The process for preparing the above components is as follows: 4 g of a vinyl-terminated polydimethylsiloxane with a viscosity of 2000 mPa·s (vinyl content of 0.08 mmol / g), 14 g of a 30000 mPa·s viscosity 45 wt% vinyl MQ resin VQM, 2.4 g of a 20 mPa·s hydrogenated silicone oil, 0.1 g of a silane coupling agent KH570, 0.1 g of a silane coupling agent KH560, 0.02 g of an inhibitor 1-ethynyl-1-cyclohexanol, and 0.2 g of a carbon black pigment are weighed into a container, placed in a homogenizer and stirred at 1300 rpm for 1 min, and the vacuum is turned on to -0.10 MPa; 0.8 g of a filler, 1.2 g of white carbon black R974, and 1.2 g of a slurry are added. R8200, stir, and evacuate to -0.10MPa; add 0.2g 2000ppm Custer platinum catalyst, stir evenly, and evacuate to -0.10MPa to obtain semi-finished product A; disperse the semi-finished product A evenly on a three-roller machine with a roller spacing of <10 microns, 2-3 times, to obtain semi-finished product B; filter the semi-finished product B with a 300-mesh filter to obtain the final product.

[0043] The obtained product was measured to have: viscosity 19640 mPa·s (Bolefield viscometer, set temperature 25°C, rotation speed 5 rpm, rotor model CP-51); thixotropic index 3.00 (Bolefield viscometer, rotor model CP-51, set temperature 25°C, thixotropic index is the viscosity ratio of rotation speed 0.5 / 5 rpm); 1*1mm chip & PCB board thrust: 1.0 Kg (adopting US military standard Mil-Std-883 standard), Young's modulus is 5.55 MPa (adopting ASTM D638-14 standard).

[0044] Example 2

[0045] The composition of the components in an organic silicone adhesive used for bonding MEMS chips is (by weight percentage):

[0046] Vinyl silicone oil 8.73%

[0047] VQM 69.81%

[0048] Hydrogen silicone oil 11.78%

[0049] Silane coupling agent 0.87%

[0050] Catalyst 0.87%

[0051] Inhibitor 0.09%

[0052] Pigment 0.87%

[0053] Filler 6.98%

[0054] The process for preparing the above components is as follows: weigh 2 g of a vinyl-terminated polydimethylsiloxane with a viscosity of 2000 mPa·s (vinyl content of 0.08 mmol / g), 16 g of a 30000 mPa·s viscosity 45 wt% vinyl MQ resin VQM, 2.7 g of a 20 mPa·s hydrogenated silicone oil, 0.1 g of a silane coupling agent KH570, 0.1 g of a silane coupling agent KH560, 0.02 g of an inhibitor 1-ethynyl-1-cyclohexanol, and 0.2 g of a carbon black pigment into a container, put the mixture into a homogenizer and stir at 1300 rpm for 1 min, then open the vacuum; add fillers 0.6 g of white carbon black R974 and 1.0 g of R8200, stir, and evacuate; add 0.2 g of 2000ppm of Custer platinum catalyst is stirred evenly and vacuumed to obtain semi-finished product A; the semi-finished product A is evenly dispersed on a three-roller machine with a roller spacing of less than 10 microns, 2-3 times, to obtain semi-finished product B; the semi-finished product B is filtered through a 300-mesh filter to obtain the final product.

[0055] Measured results: viscosity 20380mPa·s, Ti 2.87, 1*1mm chip & PCB board thrust: 1.2Kg, Young's modulus 6.20MPa.

[0056] Example 3

[0057] The composition of the components in an organic silicone adhesive used for bonding MEMS chips is (by weight percentage):

[0058]

[0059] The process for preparing the above components is as follows: 4 g of a vinyl-terminated polydimethylsiloxane with a viscosity of 2000 mPa·s (vinyl content of 0.08 mmol / g), 10 g of a 30000 mPa·s viscosity 45 wt% vinyl MQ resin VQM, 1.8 g of a 20 mPa·s hydrogenated silicone oil, 0.1 g of a silane coupling agent KH570, 0.1 g of a silane coupling agent KH560, 0.02 g of an inhibitor 1-ethynyl-1-cyclohexanol, and 0.2 g of a carbon black pigment are weighed into a container, placed in a homogenizer and stirred at 1300 rpm for 1 min, and the vacuum is turned on; 1.0 g of a filler, 1.6 g of white carbon black R974, are added, stirred, and vacuumed; 0.2 g of a 2000ppm of Custer platinum catalyst is stirred evenly and vacuumed to obtain semi-finished product A; the semi-finished product A is evenly dispersed on a three-roller machine with a roller spacing of less than 10 microns, 2-3 times, to obtain semi-finished product B; the semi-finished product B is filtered through a 300-mesh filter to obtain the final product.

[0060] The results are as follows: viscosity 20450 mPa·s, Ti 2.98, 1*1 mm chip & PCB board thrust; 0.90 Kg, Young's modulus 5.05 MPa.

[0061] Comparative Example 1

[0062]

[0063] The process for preparing the above components is as follows: weigh 7 g of vinyl-terminated polydimethylsiloxane with a viscosity of 2000 mPa·s, 8 g of silicone resin with a viscosity of 30000 mPa·s and a VQM content of 45 wt%, 1.6 g of 20 mPa·s hydrogenated silicone oil, 0.1 g of silane coupling agent KH570, 0.1 g of silane coupling agent KH560, 0.02 g of inhibitor 1-ethynyl-1-cyclohexanol, and 0.2 g of carbon black pigment into a container, put it into a homogenizer and stir it at 1300 rpm for 1 min, and then open the vacuum; add filler 1.6 g of white carbon black R974 and 1.2 g of R8200, stir, and evacuate; add 0.2 g of 2000ppm of Custer platinum catalyst is stirred evenly and vacuumed to obtain semi-finished product A; the semi-finished product A is evenly dispersed on a three-roller machine with a roller spacing of less than 10 microns, 2-3 times, to obtain semi-finished product B; the semi-finished product B is filtered through a 300-mesh filter to obtain the final product.

[0064] The results are as follows: viscosity 19230 mPa·s, Ti 2.87, 1*1 mm chip & PCB board thrust; 0.75 Kg, Young's modulus 3.20 MPa.

[0065] Comparative Example 2

[0066]

[0067] The process for preparing the above components is as follows: 16 g of vinyl-terminated polydimethylsiloxane with a viscosity of 2000 mPa·s, 0.6 g of 20 mPa·s hydrogenated silicone oil, 0.1 g of silane coupling agent KH570, 0.1 g of silane coupling agent KH560, 0.02 g of inhibitor 1-ethynyl-1-cyclohexanol, and 0.2 g of carbon black pigment are weighed and added into a container, and the mixture is put into a homogenizer for stirring at 1300 rpm for 1 min, and the vacuum is turned on; 2.8 g of white carbon black R974 filler is added, the mixture is stirred, and the mixture is vacuumed; 0.2 g of 2000 ppm of Custer platinum catalyst is added, the mixture is stirred evenly, and the mixture is vacuumed to obtain a semi-finished product A; the semi-finished product A is uniformly dispersed on a three-roller machine with a roller spacing of less than 10 microns for 2-3 times to obtain a semi-finished product B; the semi-finished product B is filtered through a 300-mesh filter to obtain a final product.

[0068] Measured results: viscosity 18600mPa·s, Ti 2.80, 1*1mm chip & PCB board thrust; 0.20Kg, Young's modulus 0.30MPa.

[0069]

[0070]

[0071] From the above table, it can be seen that Example 1, Example 2, Example 3 and Comparative Example 2 contain VQM glue, the Young's modulus of the glue is increased, the body strength is improved, and the adhesion of the chip and PCB board is improved, which shows that VQM plays a good reinforcing role.

[0072] Example 1, Example 2, Example 3, and Comparative Example 1 illustrate that as the VQM content increases, the adhesion of the chip and PCB board increases, but when the VQM content is lower than a certain value, the reinforcement effect does not meet the expected ideal.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An organic silicone adhesive used for bonding MEMS chips, characterized in that: The composition comprises the following components in parts by weight: Vinyl silicone oil 5% to 25%, VQM 50%~70%, Silicone oil containing 8% to 20% hydrogen, Silane coupling agent 0.50%~1.00%, Catalyst 0.50%~1.00%, Inhibitor 0.10%~0.50%, Pigment 0.5%~2.00%, Filler 7%~15%.

2. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The vinyl silicone oil comprises one or more low-volatility dimethyl polysiloxanes containing at least two vinyl groups in each molecule, with a viscosity of 500 to 5000 mPa·s and a vinyl content of 0.05 to 0.15 mmol / g.

3. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The VQM is a mixture of vinyl MQ resin and vinyl silicone oil, has low volatility, a viscosity of 1000-30000 mPa·s, a VQM resin content of 20-45 wt%, and a vinyl content of 0.18-0.45 mmol / g.

4. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The hydrogen-containing silicone oil includes one or more low-volatile polydimethyl silicone oils containing two or more Si-H groups in at least each molecule, wherein the Si-H groups are located on the molecular chain side and the chain end, or only on the chain side, with a viscosity of 20 to 500 mPa·s and a hydrogen content of 1.1 to 16 mmol / g.

5. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The silane coupling agent includes γ-methacryloxypropyl trimethoxysilane KH570, γ-glycidyloxypropyl trimethoxysilane KH560 or vinyl trimethoxysilane.

6. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The catalyst is an organic metal compound or an organic metal chelate containing chloroplatinic acid or platinum or palladium.

7. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The inhibitor includes one or more of 1-ethynyl-1-cyclohexanol or alkynyl alcohol derivatives, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, bis(2-ethylhexyl) maleate or maleic acid derivatives.

8. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The pigment is iron black or carbon black.

9. The organic silicone adhesive for bonding MEMS chips according to claim 1, characterized in that: The filler is gas phase carbon black or precipitated white carbon black.

10. A method for preparing an organic silicone adhesive for bonding MEMS chips as claimed in any one of claims 1 to 9, characterized in that: Add vinyl silicone oil, VQM, hydrogen silicone oil, silane coupling agent, inhibitor, and pigment into the container, stir evenly, and evacuate; Add filler, stir well, and vacuum; Add the catalyst, stir evenly, and evacuate to obtain semi-finished product A; The semi-finished product A is evenly dispersed and filtered to obtain the final product.

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