Chip filling adhesive and preparation method thereof

Abstract

The application provides a chip filling adhesive and a preparation method thereof. The chip filling adhesive comprises the following raw materials in percentage by weight: 5-40% of an epoxy resin, 2-20% of a toughening agent, 0.1-5% of a coupling agent, 1-20% of a curing agent, 0.1-0.5% of a pigment and 30-70% of a filler; wherein the filler is a negative thermal expansion material. The application can effectively reduce the viscosity at room temperature and the expansion coefficient after curing, has the characteristics of low expansion and rapid flow, can guarantee the curing speed, can be applied to packaging to improve the reliability of chips, and can be applied to the scene requiring room temperature filling.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a chip filling adhesive and its preparation method. Background Technology

[0002] Chip filler technology originated from IBM in the 1970s. It alleviates problems such as solder joint failure by dispersing mechanical and thermal stress, and is used to improve the reliability of packaged devices such as BGA and CSP in harsh environments such as vibration, drop, and temperature changes.

[0003] As chip reliability requirements increase, chip filler adhesives are seeking lower coefficients of thermal expansion. Simultaneously, production lines are placing higher demands on processes, requiring rapid flow at room temperature. Summary of the Invention

[0004] In view of this, the present invention provides a chip filling adhesive and its preparation method, which can effectively reduce the viscosity at room temperature and the coefficient of expansion after curing, and has the characteristics of low expansion and fast flow, while ensuring the curing speed. It can be applied to scenarios in packaging where chip reliability needs to be improved and room temperature filling is required.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a chip filler adhesive, characterized in that it comprises the following raw materials in weight percentages: 5-40% epoxy resin, 2-20% toughening agent, 0.1-5% coupling agent, 1-20% curing agent, 0.1-0.5% pigment, and 30-70% filler; wherein the filler is a negative thermal expansion material.

[0006] Preferably, the epoxy resin includes at least one of alicyclic epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenolic epoxy resin. It should be noted that using the above-mentioned types of epoxy resin allows for a balance between curing speed, bonding strength, etc., resulting in excellent overall performance of the chip filler.

[0007] Preferably, the toughening agent includes at least one of silicone-modified resin, polyurethane-modified resin, rubber-modified resin, and long-chain resin. It should be noted that using the above-mentioned types of toughening agents allows for a balance between bonding strength and toughness, resulting in excellent overall performance of the chip filler adhesive.

[0008] Preferably, the coupling agent comprises at least one selected from β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. It should be noted that using the above-mentioned type of silane coupling agent is beneficial for improving the wetting properties of the chip filler adhesive to the substrate and enhancing its flowability.

[0009] Preferably, the curing agent includes at least one selected from modified amine curing agents, acid anhydride curing agents, onium salt curing agents, and thiols. It should be noted that using the above-mentioned types of curing agents can improve the curing speed of the chip filler adhesive.

[0010] Preferably, the pigment includes carbon black.

[0011] Preferably, the filler includes at least one selected from zirconium tungstate, manganese nitride compound, anti-perovskite magnetic compound, and silicon aluminum oxide. It should be noted that using the above-mentioned negative thermal expansion materials as fillers can effectively reduce the coefficient of thermal expansion of the chip filler after curing, while controlling the viscosity of the chip filler and ensuring room temperature flowability.

[0012] Secondly, the present invention also provides a method for preparing the aforementioned chip filling adhesive, comprising the following steps: S1. The epoxy resin, the toughening agent, the coupling agent and the pigment are mixed to obtain a first mixture; S2. Mix the filler and the first mixture to obtain a second mixture; S3. Mix the curing agent and the second mixture to obtain chip filling adhesive.

[0013] Preferably, in step S1, the mixing time is 15-25 min; and / or, In step S2, the mixing speed is 1500~2000 rpm and the time is 100~150 min.

[0014] Preferably, in step S3, the mixing temperature is 20~25 ℃, the vacuum degree is -0.08~-0.05 MPa, the rotation speed is 500~1000 rpm, and the time is 30~60 min.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The chip filler provided by this invention, by using epoxy resin, toughening agent, coupling agent, curing agent, pigment and filler in combination, and selecting a negative thermal expansion material as filler, can effectively reduce the viscosity at room temperature and the coefficient of expansion after curing, while ensuring curing speed, fast flow at room temperature, good processability, excellent resistance to thermal cycling, and good mechanical properties. It can effectively protect the packaged components and is suitable for scenarios that require room temperature filling to improve chip reliability during packaging. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention.

[0017] Example 1 This embodiment provides a chip filler adhesive, which is composed of the following raw materials by weight: 30 g of alicyclic epoxy resin, 18 g of long carbon chain resin, 0.9 g of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 1 g of onium salt curing agent, 0.1 g of carbon black and 50 g of manganese nitrogen compound. The preparation method of chip filler is as follows: Alicyclic epoxy resin, long-chain resin, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and carbon black are added to a reactor and mixed at room temperature for 15-25 min to form a homogeneous solution. Then, manganese nitrogen compound is added to the reactor and mixed at 1500-2000 rpm for 100-150 min at room temperature. Finally, onium salt curing agent is added to the reactor and mixed at 20-25 ℃, vacuum degree -0.08--0.05 MPa, and rotation speed 500-1000 rpm for 30-60 min to obtain the chip filling adhesive product.

[0018] Example 2 This embodiment provides a chip filler adhesive, which is composed of the following raw materials by weight: 16 g of bisphenol A type epoxy resin, 13 g of polyurethane modified resin, 0.5 g of γ-mercaptopropyltrimethoxysilane, 10 g of modified amine curing agent, 0.5 g of carbon black and 60 g of silicon aluminum oxide. The preparation method of chip filler is as follows: Bisphenol A type epoxy resin, polyurethane modified resin, γ-mercaptopropyltrimethoxysilane and carbon black are added to a reaction vessel and mixed at room temperature for 15-25 min to form a homogeneous solution. Then, silicon aluminum oxide is added to the reaction vessel and mixed at 1500-2000 rpm for 100-150 min at room temperature. Finally, modified amine curing agent is added to the reaction vessel and mixed at 20-25 ℃, vacuum degree -0.08 to -0.05 MPa and rotation speed 500-1000 rpm for 30-60 min to obtain the chip filling adhesive product.

[0019] Example 3 This embodiment provides a chip filler adhesive, which is composed of the following raw materials by weight: 33.5 g of bisphenol F type epoxy resin, 5 g of rubber modified resin, 3 g of γ-glycidoxypropyltrimethoxysilane, 3 g of modified amine curing agent, 15 g of thiol, 0.5 g of carbon black and 40 g of zirconium tungstate. The preparation method of chip filler is as follows: Bisphenol F type epoxy resin, rubber modified resin, γ-glycidoxypropyltrimethoxysilane and carbon black are added to a reaction vessel and mixed at room temperature for 15-25 min to form a homogeneous solution. Then zirconium tungstate is added to the reaction vessel and mixed at 1500-2000 rpm at room temperature for 100-150 min. Finally, modified amine curing agent and thiol are added to the reaction vessel and mixed at 20-25 ℃, vacuum degree -0.08 to -0.05 MPa and rotation speed 500-1000 rpm for 30-60 min to obtain the chip filling adhesive product.

[0020] Comparative Example 1 This comparative example provides a chip filler adhesive composed of the following raw materials by weight: 16 g of bisphenol A type epoxy resin, 3 g of modified epoxy acrylate, 0.5 g of γ-mercaptopropyltrimethoxysilane, 10 g of modified amine curing agent, 0.5 g of carbon black and 70 g of aluminum oxide. The preparation method of chip filler is as follows: Bisphenol A type epoxy resin, modified epoxy acrylate, γ-mercaptopropyltrimethoxysilane, and carbon black are added to a reaction vessel and mixed at room temperature for 15-25 min to form a homogeneous solution. Then, aluminum oxide is added to the reaction vessel and mixed at 1500-2000 rpm at room temperature for 60-100 min. Finally, a modified amine curing agent is added to the reaction vessel and stirred at 20-25 ℃, a vacuum of -0.08 to -0.05 MPa, and a stirring speed of 500-1000 rpm for 30-60 min to obtain the chip filling adhesive product.

[0021] Comparative Example 2 This comparative example provides a chip filler adhesive composed of the following raw materials by weight: 30 g of alicyclic epoxy resin, 18 g of long carbon chain resin, 0.9 g of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 1 g of onium salt curing agent, 0.1 g of carbon black and 50 g of silica. The preparation method of chip filler is as follows: Alicyclic epoxy resin, long-chain resin, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and carbon black are added to a reactor and mixed at room temperature for 15-25 min to form a homogeneous solution. Then, silica is added to the reactor and mixed at 1500-2000 rpm for 100-150 min at room temperature. Finally, onium salt curing agent is added to the reactor and mixed at 20-25 ℃, vacuum degree -0.08--0.05 MPa, and rotation speed 500-1000 rpm for 30-60 min to obtain the chip filling adhesive product.

[0022] Comparative Example 3 This comparative example provides a chip filler adhesive composed of the following raw materials by weight: 33.5 g of bisphenol F type epoxy resin, 5 g of rubber modified resin, 3 g of γ-glycidoxypropyltrimethoxysilane, 3 g of modified amine curing agent, 15 g of thiol, 0.5 g of carbon black, 10 g of zirconium tungstate, and 30 g of silica. The preparation method of chip filler is as follows: Bisphenol F type epoxy resin, rubber modified resin, γ-glycidoxypropyltrimethoxysilane and carbon black are added to a reaction vessel and mixed at room temperature for 15-25 min to form a homogeneous solution. Then zirconium tungstate and silica are added to the reaction vessel and mixed at 1500-2000 rpm at room temperature for 100-150 min. Finally, modified amine curing agent and thiol are added to the reaction vessel and mixed at 20-25 ℃, vacuum degree -0.08 to -0.05 MPa and rotation speed 500-1000 rpm for 30-60 min to obtain the chip filling adhesive product.

[0023] Performance Tests and Results The chip filling adhesive products obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests, and the results are shown in Table 1.

[0024] (1) Viscosity: Rheological test, 25 ℃, rotation speed of 20 rpm, unit is mPa•s.

[0025] (2) Curing speed: DSC curing curve, heating rate is 100 ℃ / min, the curing temperature is reached, and the temperature is held for 30 min. The time when the degree of curing is 95% is taken.

[0026] (3) Coefficient of thermal expansion (CTE): TMA test, heating rate 10 ℃ / min, according to ASTM D696 test, unit μm / m℃.

[0027] Table 1 Performance test results of the chip filler obtained in each embodiment and comparative example

[0028] As can be seen from Table 1, the chip filler provided by the present invention can effectively reduce the viscosity at room temperature and the coefficient of expansion after curing, while ensuring the curing speed, fast flow at room temperature, good processability, excellent resistance to thermal cycling, and good mechanical properties. It can effectively protect the packaged components and is suitable for scenarios that require room temperature filling to improve the reliability of the chip during packaging.

[0029] Unless otherwise specified, all raw materials used in this invention are existing substances that can be purchased directly from the market.

[0030] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A chip filler adhesive, characterized in that, The raw materials include the following weight percentages: epoxy resin 5-40%, toughening agent 2-20%, coupling agent 0.1-5%, curing agent 1-20%, pigment 0.1-0.5%, and filler 30-70%; wherein the filler is a negative thermal expansion material.

2. The chip filling adhesive according to claim 1, characterized in that, The epoxy resin includes at least one of alicyclic epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, and phenolic type epoxy resin.

3. The chip filling adhesive according to claim 1, characterized in that, The toughening agent includes at least one of silicone-modified resin, polyurethane-modified resin, rubber-modified resin, and long-chain resin.

4. The chip filling adhesive according to claim 1, characterized in that, The coupling agent includes at least one of β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

5. The chip filling adhesive according to claim 1, characterized in that, The curing agent includes at least one of modified amine curing agents, acid anhydride curing agents, onium salt curing agents, and thiols.

6. The chip filling adhesive according to claim 1, characterized in that, The pigments include carbon black.

7. The chip filling adhesive according to claim 1, characterized in that, The filler includes at least one of zirconium tungstate, manganese nitrogen compound, anti-perovskite magnetic compound, and silicon aluminum oxide.

8. The method for preparing the chip filling adhesive according to any one of claims 1-7, characterized in that, Includes the following steps: S1. The epoxy resin, the toughening agent, the coupling agent and the pigment are mixed to obtain a first mixture; S2. Mix the filler and the first mixture to obtain a second mixture; S3. Mix the curing agent and the second mixture to obtain chip filling adhesive.

9. The method for preparing the chip filling adhesive according to claim 8, characterized in that, In step S1, the mixing time is 15-25 min; and / or, In step S2, the mixing speed is 1500~2000 rpm and the time is 100~150 min.

10. The method for preparing chip filling adhesive according to claim 8, characterized in that, In step S3, the mixing temperature is 20~25 ℃, the vacuum degree is -0.08~-0.05 MPa, the rotation speed is 500~1000 rpm, and the time is 30~60 min.

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