Low-warpage chip adhesive composition, preparation method and application

Abstract

The invention provides a low-warpage chip adhesive composition as well as a preparation method and application thereof, and the low-warpage chip adhesive composition is prepared from the following components in parts by mass: 10 to 25 parts of acrylate, 2 to 8 parts of hydroxyl acrylate, 5 to 20 parts of acrylate oligomer, 10 to 25 parts of BMI, 1 to 5 parts of peroxide, 20 to 60 parts of filler and 0.2 to 1 part of anti-precipitation aid. The low-warpage chip adhesive disclosed by the invention adopts components with specific contents, realizes relatively good overall interaction, has the characteristics of rapid curing, good adhesive property and no resin precipitation, greatly improves the warpage problem of a large-size chip after surface mounting, and is suitable for the field of large chip surface mounting adhesives such as camera modules and the like.

Description

Technical Field

[0001] This invention belongs to the field of chip packaging technology, specifically relating to a low-warpage chip adhesive composition, its preparation method, and its application. Background Technology

[0002] As semiconductor chip packaging requirements increase, chip bonding materials need to possess higher performance. Epoxy resin adhesives are widely used in industrial fields due to their excellent physicochemical properties, but they suffer from high curing temperatures and long curing times, making it difficult to meet the needs of low-temperature sensitive devices and automated production.

[0003] In recent years, low-temperature rapid curing epoxy resin adhesives have attracted attention. They can achieve rapid curing at low temperatures, but mainly use rigid epoxy resins such as bisphenol A. When bonding flexible plastics or large chips, the deformation and warpage after curing are large, which limits their application in bonding large chips.

[0004] To address these issues, developing a chip adhesive that can cure quickly, maintain good adhesion, and exhibit low warpage has become an urgent problem. Existing chip adhesives are mainly based on epoxy resins and acrylic resins, but each has its limitations: epoxy resins exhibit small deformation after curing but poor flexibility; acrylic resins have good flexibility but insufficient interfacial bond strength and high curing shrinkage.

[0005] Therefore, developing a new type of low-warpage chip adhesive that can meet the requirements of rapid curing, effectively control warpage, and has good adhesion and interfacial bonding properties is of great significance for improving the reliability and efficiency of chip packaging. Summary of the Invention

[0006] The first objective of this invention is to provide a low-warpage chip adhesive composition.

[0007] Therefore, the above-mentioned objective of the present invention is achieved through the following technical solution:

[0008] A low-warpage chip adhesive composition, comprising the following components by weight: 10-25 parts acrylate, 2-8 parts hydroxy acrylate, 5-20 parts acrylate oligomer, 10-25 parts BMI, 1-5 parts peroxide, 20-60 parts filler, and 0.2-1 part anti-exudation agent.

[0009] The acrylate oligomer contains at least one epoxy group and one acrylate group.

[0010] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0011] As a preferred technical solution of the present invention: the acrylate oligomer is selected from epoxy acrylate oligomers having acrylate groups and epoxy functional groups on the same main chain, and its viscosity at 60°C is 1000~8000 mPa·s.

[0012] As a preferred embodiment of the present invention, the acrylate is a monofunctional monomer selected from at least one of isodecanyl acrylate, dicyclopentenyl ethoxyacrylate, hexadecyl acrylate, octadecyl acrylate, lauryl acrylate, and lauryl methacrylate.

[0013] As a preferred embodiment of the present invention, the hydroxy acrylate is selected from at least one of di-trimethylolpropane tetraacrylate, trimethylolpropane trimethacrylate, and tri(2-hydroxyethyl)isocyanurate triacrylate.

[0014] As a preferred embodiment of the present invention, the BMI is selected from at least one of UMI-0, BMI-TCD, and BMI-968.

[0015] BMI material, introduced into acrylate curing systems as a high-temperature modifier, primarily functions to improve processing compatibility through its liquid properties. Furthermore, by copolymerizing with or forming interpenetrating networks with acrylates, it significantly enhances the heat resistance, high-temperature mechanical properties, and dimensional stability of the cured material. As a matrix resin, BMI offers advantages such as rapid curing, low stress, and excellent high-temperature adhesion.

[0016] As a preferred embodiment of the present invention, the peroxide is selected from at least one of di(4-tert-butylcyclohexyl) peroxide, benzoyl peroxide, tert-butyl peroxide-2-ethylhexanoate, dicumyl peroxide, and di(hexadecyl) peroxide.

[0017] As a preferred embodiment of the present invention, the filler is selected from at least one of silica powder, alumina, calcium carbonate, talc, and fumed silica.

[0018] As a preferred embodiment of the present invention, the anti-exudation agent is selected from at least one of perfluoropolyether glycol and fluorocarbon surfactant.

[0019] The second objective of this invention is to provide a method for preparing a low-warpage chip adhesive.

[0020] Therefore, the above-mentioned objective of the present invention is achieved through the following technical solution:

[0021] A method for preparing a low-warpage chip adhesive includes the following steps:

[0022] (1) The acrylate, hydroxy acrylate, acrylate oligomer, BMI and anti-precipitation additive in the low warp chip adhesive composition described above are stirred and dissolved in proportion to mass, cooled and then peroxide and optional polymerization inhibitor are added and stirred evenly to obtain resin mother liquor.

[0023] (2) Add filler to the obtained resin mother liquor, mix evenly, and then degas under vacuum degree ≤ -0.095 MPa for 15-25 min (e.g., 15 min, 16 min, 18 min, 20 min, 22 min, 24 min, 25 min) to obtain low warpage chip adhesive.

[0024] Another objective of this invention is to provide an application of the low-warpage chip adhesive prepared by the method described above in large-size chip packaging.

[0025] This invention provides a low-warpage chip adhesive composition, preparation method, and application. The low-warpage chip adhesive of this invention uses specific component content to achieve better overall interaction, and has the characteristics of rapid curing, good adhesion performance, and no resin exudation. It greatly improves the warpage problem after large-size chip die bonding and is suitable for the field of large chip mounting adhesives such as camera modules. Detailed Implementation

[0026] The present invention will be described in further detail with reference to specific embodiments.

[0027] The raw materials used in this invention are not specifically limited in their source; any commercially available products well-known to those skilled in the art can be used, and they can also be prepared using well-known technical solutions. Table 1 below shows the information on the raw materials used in this invention.

[0028] Table 1

[0029]

[0030] Experimental Examples

[0031] According to the formula, acrylate, hydroxy acrylate, acrylate oligomer, BMI, and anti-precipitation additive are stirred and dissolved, cooled, and then peroxide is added and stirred evenly to obtain resin mother liquor.

[0032] Filler was added to the resin mother liquor, and after mixing evenly, degassing was carried out under vacuum of ≤-0.095 MPa for 20 min to obtain low warpage chip adhesive.

[0033] The proportions of each component in the examples and comparative examples are shown in Table 2. In Table 2, the amount of each component is in parts by mass.

[0034] Table 2

[0035]

[0036] Comparative Example 5: Commercially available product A, epoxy mercaptan low-temperature curing system.

[0037] Comparative Example 6, Commercially available product B, epoxy-acrylic hybrid system.

[0038] The adhesives used in the examples and comparative examples were tested as follows:

[0039] 1) Die-Shear Strength: The test method refers to "HG / T 5912-2021 Conductive Adhesives". The silicon wafer size is 2 mm × 2 mm; the substrate is silver-plated copper sheet; the curing conditions are a forced-air oven at 130℃ for 0.5 h; the test equipment is a DAGE-4000P multi-functional push-pull tester, Nordson DAGE Precision Industries LTD, USA; the shear strength is the magnitude of the push force (unit is kgF); the test temperature is 23℃±2℃; 10 samples of each adhesive are used, and the average value is taken.

[0040] 2) Chip warpage measurement: A silver-plated frame was used. COM chips with dimensions of 5 mm × 6 mm and 8 mm × 9 mm were baked and cured at 130℃ for 0.5 h. Chip surface warpage was measured using a microscope, with units in μm (testing equipment: Keyence microscope VHX-7100).

[0041] 3) RBO Measurement: The test was conducted according to the test method provided in "HG / T 5912-2021 Conductive Adhesives". After the adhesive was applied to the silver-plated copper sheet and cured, it was observed through an optical microscope to measure the size of the resin precipitation (i.e., RBO) around the conductive adhesive.

[0042] Table 3

[0043]

[0044] The test results are shown in Table 3. By using specific amounts of each component, the present invention achieves better overall interaction, and has the characteristics of rapid curing, good adhesion performance and no RBO, which greatly improves the warping problem after large-size chip die bonding.

[0045] Compared to Example 1, Comparative Examples 1, 2, and 3 differed only in the acrylate oligomer ratio. Under the same material ratio, these examples resulted in increased chip warpage and improved chip thrust. Furthermore, due to the lower functional group content of the acrylate oligomer, a higher proportion of acrylate oligomer in Example 1 resulted in a slight decrease in chip thrust compared to Example 2. Compared to Example 1, Example 3 only increased the acrylate oligomer content. Under the same material ratio, this resulted in decreased chip warpage and a slight decrease in chip thrust.

[0046] Compared to Example 1, Example 4 differs only in the type of BMI. Under the same material ratio, the result is an increase in chip warpage and a significant improvement in chip thrust.

[0047] Compared to Example 1, Example 5 differs only in the type of acrylate. As a result, under the same material ratio, the chip warpage is reduced and the chip thrust is increased.

[0048] Compared to Example 1, Comparative Example 2, which only omitted BMI material, resulted in increased chip warpage under the same material ratio, especially a significant increase in warpage for 8 mm*9 mm chips, and a decrease in chip thrust.

[0049] Compared to Example 1, Comparative Example 3 only lacked the addition of hydroxy acrylate material. As a result, under the same material ratio, the chip thrust was significantly reduced and the chip warpage was decreased.

[0050] Compared to Example 1, Comparative Example 4 did not include an anti-precipitation agent, resulting in a significant increase in RBO under the same material ratio.

[0051] Compared to Example 1, Comparative Examples 5 and 6 showed that the chip warpage and RBO issues of commercially available products were not as good as those of Example 1.

[0052] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A low-warpage chip adhesive composition, characterized in that: By weight, it includes the following components: 10-25 parts acrylate, 2-8 parts hydroxy acrylate, 5-20 parts acrylate oligomer, 10-25 parts BMI, 1-5 parts peroxide, 20-60 parts filler, and 0.2-1 parts anti-exudation agent. The acrylate oligomer contains at least one epoxy group and one acrylate group.

2. The low warpage chip adhesive composition according to claim 1, characterized in that: The acrylate oligomer is selected from epoxy acrylate oligomers having acrylate groups and epoxy functional groups on the same main chain, and its viscosity at 60°C is 1000~8000 mPa·s.

3. The low-warpage chip adhesive composition according to claim 1, characterized in that: The acrylate is a monofunctional monomer selected from at least one of isodecanyl acrylate, dicyclopentenyl ethoxyacrylate, hexadecyl acrylate, octadecyl acrylate, lauryl acrylate, and lauryl methacrylate.

4. The low warpage chip adhesive composition according to claim 1, characterized in that: The hydroxy acrylate is selected from at least one of di-trimethylolpropane tetraacrylate, trimethylolpropane trimethacrylate, and tri(2-hydroxyethyl)isocyanurate triacrylate.

5. The low-warpage chip adhesive composition according to claim 1, characterized in that: The BMI is selected from at least one of UMI-0, BMI-TCD, and BMI-968.

6. The low-warpage chip adhesive composition according to claim 1, characterized in that: The peroxide is selected from at least one of di(4-tert-butylcyclohexyl) peroxide, benzoyl peroxide, tert-butyl peroxide-2-ethylhexanoate, dicumyl peroxide, and di(hexadecyl) peroxide.

7. The low-warpage chip adhesive composition according to claim 1, characterized in that: The filler is selected from at least one of silica powder, alumina, calcium carbonate, talc, and fumed silica.

8. The low warpage chip adhesive composition according to claim 1, characterized in that: The anti-exudation agent is selected from at least one of perfluoropolyether glycol and fluorocarbon surfactant.

9. A method for preparing a low-warpage chip adhesive, characterized in that, Includes the following steps: (1) The acrylate, hydroxy acrylate, acrylate oligomer, BMI and anti-precipitation additive in the low warp chip adhesive composition as described in claim 1 are stirred and dissolved in proportion to mass, cooled and then peroxide is added and stirred evenly to obtain resin mother liquor. (2) Add filler to the obtained resin mother liquor, mix evenly, and then degas for 15-25 min under vacuum degree ≤-0.095 MPa to obtain low warpage chip adhesive.

10. The application of the low-warpage chip adhesive prepared by the method of claim 9 in large-size chip packaging.

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