Resin composition with low water absorption rate, chip bonding film, preparation method of chip bonding film and stacked packaging structure

Abstract

The invention discloses a low-water-absorption resin composition, a chip adhesive film, a preparation method of the chip adhesive film and a stacked packaging structure. The resin composition comprises an inorganic filler, epoxy resin, a polymer containing an epoxy group and a siloxane chain, a curing agent and an accelerant, wherein the inorganic filler accounts for 35-40 parts by mass; the epoxy resin comprises 20-25 parts by mass of bisphenol A epoxy resin, 10-15 parts by mass of dicyclopentadiene phenol epoxy resin, 8-10 parts by mass of bisphenol F epoxy resin and 8-10 parts by mass of polyurethane modified epoxy resin; the polymer containing the epoxy group and the siloxane chain comprises 8 to 15 parts by mass of bisphenol A epoxy-siloxane block copolymer resin. The film-shaped object prepared from the resin composition has low moisture absorption rate and high adhesive force, can still keep high adhesive force after reflow soldering, is applied to a stack packaging structure as an adhesive film, and is beneficial to improving the reliability of a stack packaging device.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor chip packaging technology, and specifically relates to a resin composition with low water absorption, a chip adhesive film, a preparation method thereof, and a stacked packaging structure. Background Art

[0002] In stacked packages, die attach film (DAF) is used to attach the chip to the substrate. Die attach film is porous and hydrophilic, easily absorbing moisture from the air. During the reflow process, the moisture absorbed by the die attach film evaporates, generating vapor pressure. When this vapor pressure acts on the pores within the die attach film, it enlarges the pores and may even cause delamination, affecting the overall reliability of the packaged device. Summary of the Invention

[0003] One of the purposes of the present application is to provide a resin composition with low water absorption, comprising an inorganic filler, an epoxy resin, a polymer containing epoxy groups and siloxane chains, a curing agent and an accelerator; wherein the inorganic filler is 35-40 parts by mass; the epoxy resin comprises 20-25 parts by mass of bisphenol A epoxy resin, 10-15 parts by mass of dicyclopentadiene phenol epoxy resin, 8-10 parts by mass of bisphenol F epoxy resin and 8-10 parts by mass of polyurethane modified epoxy resin; and the polymer containing epoxy groups and siloxane chains comprises 8-15 parts by mass of bisphenol A epoxy-siloxane block copolymer resin.

[0004] In some embodiments, the polymer containing epoxy groups and siloxane chains further includes epoxy-modified silicone resins.

[0005] In some embodiments, the inorganic filler is selected from silica.

[0006] In some embodiments, the bisphenol A epoxy resin has an epoxy equivalent weight of 7500 g / eq to 8900 g / eq.

[0007] In some embodiments, the dicyclopentadiene phenol epoxy resin has an epoxy equivalent weight of 250 g / eq to 280 g / eq.

[0008] In some embodiments, the bisphenol F epoxy resin has an epoxy equivalent weight of 155 g / eq to 165 g / eq.

[0009] In some embodiments, the polyurethane-modified epoxy resin has an epoxy equivalent weight of 210 g / eq to 250 g / eq.

[0010] In some embodiments, the bisphenol A epoxy-siloxane block copolymer resin has an epoxy equivalent weight of 650 g / mol to 900 g / mol.

[0011] A second object of the present application is to provide a die attach film, which is obtained by film-forming the above resin composition.

[0012] A third object of the present application is to provide a method for preparing a die bonding film, comprising: Adding epoxy resin and polymer containing epoxy groups and siloxane chains into solvent to dissolve; Then add inorganic filler, curing agent and accelerator, mix and grind until a colloid is formed; Applying the colloid to obtain a chip bonding film; Among them, the inorganic filler is 35-40 parts by mass; the epoxy resin includes 20-25 parts by mass of bisphenol A epoxy resin, 10-15 parts by mass of dicyclopentadiene phenol epoxy resin, 8-10 parts by mass of bisphenol F epoxy resin and 8-10 parts by mass of polyurethane modified epoxy resin; the polymer containing epoxy groups and siloxane chains includes 8-15 parts by mass of bisphenol A epoxy-siloxane block copolymer resin.

[0013] The fourth object of the present application is to provide a stacked packaging structure, comprising a substrate, one or more chip stacking structures located on the substrate, and a plastic package; the chip stacking structure comprises a plurality of chips stacked in sequence; wherein, the chip stacking structure and the substrate are bonded through the above-mentioned adhesive film; the chips in the chip stacking structure are bonded through the above-mentioned adhesive film or lead adhesive film; the plastic package encapsulates the substrate and the one or more chip stacking structures located on the substrate.

[0014] Compared with the prior art, this application has the following advantages and beneficial effects: 1. The film prepared from the resin composition of this application has low moisture absorption and high adhesion, maintaining high adhesion even after reflow soldering. Its application as an adhesive film in package-on-package structures helps improve the reliability of package-on-package devices. 2. The film prepared from the resin composition of the present application has a relatively low modulus. The low modulus helps to release stress, thereby reducing or even avoiding chip failure caused by stress release. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 The figure is a schematic diagram of a specific stacked packaging structure.

[0017] Reference numerals: 10 - substrate, 20 - chip stacking structure, 21 - first chip, 22 - second chip, 23 - third chip, 30 - adhesive film, 40 - wire adhesive film. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0019] An embodiment of the present application provides a resin composition with low water absorption, comprising an inorganic filler, an epoxy resin, a polymer containing epoxy groups and siloxane chains, a curing agent, and an accelerator; wherein the inorganic filler comprises 35-40 parts by mass; the epoxy resin comprises 20-25 parts by mass of bisphenol A epoxy resin, 10-15 parts by mass of dicyclopentadiene phenol epoxy resin, 8-10 parts by mass of bisphenol F epoxy resin, and 8-10 parts by mass of polyurethane-modified epoxy resin; and the polymer containing epoxy groups and siloxane chains comprises 8-15 parts by mass of bisphenol A epoxy-siloxane block copolymer resin.

[0020] In the present application, the inorganic filler is mainly used to reduce the internal stress and thermal expansion coefficient of the resin composition system, and a conventional inorganic filler is selected. In some embodiments, the inorganic filler is selected from silica, preferably spherical silica, and more preferably spherical silica with a D50 of 0.2 μm-0.4 μm.

[0021] In this application, bisphenol A epoxy resin is mainly used to provide strength and adhesion to the resin composition; dicyclopentadiene phenol epoxy resin (DCPC epoxy resin) contains dicyclopentadiene structural units and phenol structural units, which can combine the heat resistance of dicyclopentadiene structure and the reactivity of phenol structure; bisphenol F epoxy resin is mainly used to adjust the reactivity and viscosity of the resin composition; polyurethane modified epoxy resin is mainly used to provide flexibility and adhesion to the resin composition.

[0022] In some embodiments, the epoxy equivalent weight of the bisphenol A epoxy resin is 7500 g / eq-8900 g / eq, and the amount thereof can be 20-25 parts by mass, 20-22 parts by mass, or 22-25 parts by mass.

[0023] In some embodiments, the epoxy equivalent of the dicyclopentadiene phenol epoxy resin is 250 g / eq-280 g / eq, and the amount thereof can be 10-15 parts by mass, 10-12 parts by mass, or 12-15 parts by mass.

[0024] In some embodiments, the epoxy equivalent weight of the bisphenol F epoxy resin is 155 g / eq-165 g / eq, and the epoxy equivalent weight of the polyurethane-modified epoxy resin is 210 g / eq-250 g / eq.

[0025] In the present application, in the polymer containing epoxy groups and siloxane chains, the siloxane chains are highly hydrophobic and can prevent water molecules from entering; in addition, the siloxane chains are closely arranged, and the epoxy matrix forms a three-dimensional network structure through cross-linking reaction, making the polymer molecular structure more dense and further preventing the entry of water molecules; therefore, the polymer containing epoxy groups and siloxane chains should have low water absorption.

[0026] In polymers containing epoxy groups and siloxane chains, the epoxy groups are highly reactive and can react with active groups on the surface of the bonding interface to form chemical bonds, thereby achieving adhesion to the bonding interface. During the curing process, the epoxy groups form a network of cross-linked structures, further enhancing bond strength. Furthermore, the siloxane chains have good surface activity, allowing the polymer to spread rapidly across the bonding interface and better wet the interface. The siloxane chains are also densely packed, allowing the polymer to diffuse rapidly across the bonding interface, strengthening the molecular forces between the polymer and the bonding interface. Furthermore, during the curing process, the hydroxyl groups on the siloxane chains can form hydrogen bonds with polar groups on the surface of the bonding interface, further enhancing adhesion. Therefore, the presence of siloxane chains helps further enhance the bonding properties of the polymer, and polymers containing epoxy groups and siloxane chains should also exhibit excellent bonding properties.

[0027] However, experiments have shown that not all polymers containing epoxy groups and siloxane chains in the epoxy resin system of this application can significantly reduce water absorption and significantly improve bonding performance. When a bisphenol A epoxy-siloxane block copolymer resin is selected as the polymer containing epoxy groups and siloxane chains, the water absorption of the resin composition can be significantly reduced and the bonding performance can be significantly enhanced.

[0028] In some embodiments, the epoxy equivalent weight of the bisphenol A epoxy-siloxane block copolymer resin is 650 g / mol-900 g / mol, and the amount thereof can be 8-15 parts by mass, 8-10 parts by mass, 8-12 parts by mass, 10-12 parts by mass, 10-15 parts by mass, or 12-15 parts by mass.

[0029] In some embodiments, the polymer containing epoxy groups and siloxane chains further includes epoxy-modified silicone resins.

[0030] In this application, a curing agent is used to initiate a curing reaction with an epoxy resin or a polymer containing epoxy groups and siloxane chains at a certain temperature, and an accelerator is used to accelerate the curing reaction. The curing agent and accelerator should be selected to be compatible with the epoxy resin or the polymer containing epoxy groups and siloxane chains.

[0031] In some embodiments, a phenolic resin curing agent is used as the curing agent, and an imidazole accelerator is used as the accelerator. The curing agent and accelerator are determined based on the amount of epoxy resin and the polymer containing epoxy groups and siloxane chains. The amount of curing agent used can generally be 12-18 parts by mass, 15-18 parts by mass, 16-18 parts by mass, or 15-16 parts by mass, and the amount of accelerator used can generally be 0.6-1.0 parts by mass or 0.65-0.7 parts by mass.

[0032] The die bonding film provided in the embodiments of the present application is obtained by subjecting the above resin composition to a film-forming process.

[0033] The preparation method of the chip bonding film provided in the embodiment of the present application is: adding epoxy resin and a polymer containing epoxy groups and siloxane chains into a solvent to dissolve; then adding an inorganic filler, a curing agent and an accelerator to mix and grind until a colloid is formed; and coating the colloid to obtain a chip bonding film.

[0034] In some embodiments, a bead mill is selected to grind the mixture, and a coater is selected to coat the mixture.

[0035] In some embodiments, the method further includes: vacuum degassing the colloid before coating.

[0036] The chip bonding film of the present application can be used in stacked packaging to bond a chip to a substrate and / or to bond chips to each other.

[0037] See also Figure 1 , shown is a schematic diagram of a specific stacked package structure, which shows a substrate 10, a chip stacking structure 20 located on the substrate 10, and a plastic package (not shown in the figure); the chip stacking structure 20 includes a plurality of chips stacked in sequence. In this figure, the chip stacking structure 20 includes a first chip 21, a second chip 22, and a third chip 23 stacked in sequence; the chip stacking structure 20 is bonded to the substrate 10 through an adhesive film 30; the chips are bonded to each other through an adhesive film 30 or a wire bonding film 40 according to actual conditions. The wire bonding film is FOW (Film on Wire). In this figure, the first chip 21 and the second chip 22 are bonded through the adhesive film 30, and the second chip 22 and the third chip 23 are bonded through the wire bonding film 40; the plastic package is used to encapsulate the whole.

[0038] In order to further illustrate the present invention, the following examples and comparative examples are provided for detailed description. The raw materials used in the examples and comparative examples are as follows: Inorganic filler: commercially available spherical silica, D50 particle size 0.2 μm; Bisphenol A epoxy resin: brand JER4250, epoxy equivalent weight 7500g / eq-8900g / eq; Dicyclopentadiene phenol epoxy resin: brand HP-7200, epoxy equivalent weight 250g / eq-280g / eq; Epoxy modified silicone resin: brand SH-023-4, epoxy equivalent weight 625g / eq-1667g / eq; Bisphenol A epoxy-siloxane block copolymer: brand ALBIFLEX ® 297, epoxy equivalent weight: 650g / mol-900g / mol; Bisphenol F type epoxy resin: brand 8170, epoxy equivalent weight 155g / eq-165g / eq; Polyurethane modified epoxy resin: brand EPU-133, epoxy equivalent weight 210g / eq-250g / eq; Phenolic curing agent: brand SH-4064, curing equivalent 168g / eq-172g / eq; Accelerator: 4,5-bis(hydroxymethyl)-2-phenyl-1H-imidazole.

[0039] The raw materials and dosages of the examples and comparative examples are shown in Table 1.

[0040] Table 1 Raw materials, dosage and performance parameters of Examples 1-7 The preparation methods of the epoxy resin compositions of the above examples and comparative examples are the same, namely: first, epoxy resin and a polymer containing epoxy groups and siloxane chains are dissolved in propylene glycol methyl ether acetate (PMA) according to mass; then, inorganic filler, curing agent and accelerator are added and mixed according to mass, and the mixture is ground into a gel using a bead mill.

[0041] The film-forming method of the epoxy resin composition of the above examples and comparative examples is: vacuum degassing the colloid first, and then coating it using a coating machine.

[0042] The performance parameter data of the examples and comparative examples are listed in Table 2.

[0043] Table 2 Raw materials, dosage and performance parameters of Comparative Examples 1-8

[0044] The detection methods of the performance parameters of the above-mentioned examples and comparative examples are as follows: 1. Modulus and glass transition temperature Tg: The epoxy resin composition was subjected to a film-forming treatment to obtain a film with a thickness of 25 μm. Ten layers of the film were stacked and then cured at 180°C for 2 h. Samples with a size of 25 mm × 6.5 mm and a thickness of 0.23 mm to 0.25 mm were cut and tested for modulus and glass transition temperature Tg using a dynamic mechanical analyzer, referring to standard ASTM E2254-2018, measurement mode: Tension: Film, heating to 250°C at 5°C / min, taking the modulus at 25°C, and reading the glass transition temperature Tg.

[0045] 2. Moisture absorption rate: The epoxy resin composition was subjected to film-forming treatment to obtain a film with a thickness of 25 μm. 20 layers of the film were stacked and cut into strips of 8 cm × 1 cm in size. Five strips were taken and cured at 180°C for 2 h. The initial weight Ma of each strip was weighed. The strips were placed in a high-temperature and high-pressure cooking apparatus for a cooking test at 120°C for 24 h. After the test, the surface moisture of the strips was wiped dry and the weight Mb was weighed. The moisture absorption rate of each strip (Mb-Ma) / Ma was calculated, and the moisture absorption rate of the five strips was averaged.

[0046] 3. Adhesion and adhesion after reflow soldering: The epoxy resin composition was processed into a film with a thickness of 25 μm. A 10 mm × 10 mm film was taken and attached to a 10 mm × 10 mm silicon wafer. A 2 mm × 2 mm silicon wafer was then covered on the film and fixed with a clamp. The film was cured at 180°C for 2 h, and the shear bond strength, i.e., adhesion, was tested using a multi-function shear force tester.

[0047] The epoxy resin composition was processed into a 25μm thick film. A 10mm×10mm film was then attached to a 10mm×10mm silicon wafer. A 2mm×2mm silicon wafer was then placed over the film and secured with a clamp. The film was then cured at 180°C for 2 hours. The film was then placed in a constant temperature and humidity chamber at 30°C and 60% relative humidity for 192 hours. The film was then reflowed at 260°C / 90s, repeated three times, and the shear bond strength (i.e., post-reflow adhesion) was measured using a multi-function shear force tester.

[0048] As can be seen from Tables 1 and 2, the addition of a bisphenol A epoxy-siloxane block copolymer resin can reduce moisture absorption, improve adhesion, and improve post-reflow adhesion. In particular, when the various raw material components are used in specific amounts, the epoxy resin composition exhibits significantly reduced moisture absorption, significantly improved adhesion and post-reflow adhesion, and significantly reduced modulus.

[0049] The above embodiments are merely for the purpose of illustrating the embodiments and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications may be made based on the above descriptions. It is not necessary and impossible to enumerate all implementation methods here. Therefore, any obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A resin composition with low water absorption, characterized in that: The invention comprises an inorganic filler, an epoxy resin, a polymer containing epoxy groups and siloxane chains, a curing agent and an accelerator; wherein the inorganic filler comprises 35-40 parts by mass; the epoxy resin comprises 20-25 parts by mass of bisphenol A epoxy resin, 10-15 parts by mass of dicyclopentadiene phenol epoxy resin, 8-10 parts by mass of bisphenol F epoxy resin and 8-10 parts by mass of polyurethane modified epoxy resin; and the polymer containing epoxy groups and siloxane chains comprises 8-15 parts by mass of bisphenol A epoxy-siloxane block copolymer resin.

2. The resin composition according to claim 1, wherein: The polymer containing epoxy groups and siloxane chains also includes epoxy-modified silicone resins.

3. The resin composition according to claim 1, wherein: The inorganic filler is silicon dioxide.

4. The resin composition according to claim 1, wherein: The epoxy equivalent of the bisphenol A epoxy resin is 7500 g / eq-8900 g / eq.

5. The resin composition according to claim 1, wherein: The epoxy equivalent of the dicyclopentadiene phenol epoxy resin is 250 g / eq-280 g / eq.

6. The resin composition according to claim 1, wherein: The epoxy equivalent of the bisphenol F epoxy resin is 155 g / eq-165 g / eq.

7. The resin composition according to claim 1, wherein: The epoxy equivalent of the polyurethane modified epoxy resin is 210 g / eq-250 g / eq.

8. The resin composition according to claim 1, wherein: The epoxy equivalent of the bisphenol A epoxy-siloxane block copolymer resin is 650 g / mol-900 g / mol.

9. A die bonding film, characterized in that: The resin composition according to any one of claims 1 to 8 is obtained by subjecting the resin composition to film-forming treatment.

10. A method for preparing a die bonding film, characterized in that: include: Adding epoxy resin and polymer containing epoxy groups and siloxane chains into solvent to dissolve; Then add inorganic filler, curing agent and accelerator, mix and grind until a colloid is formed; Applying the colloid to obtain a chip bonding film; Among them, the inorganic filler is 35-40 parts by mass; the epoxy resin includes 20-25 parts by mass of bisphenol A epoxy resin, 10-15 parts by mass of dicyclopentadiene phenol epoxy resin, 8-10 parts by mass of bisphenol F epoxy resin and 8-10 parts by mass of polyurethane modified epoxy resin; the polymer containing epoxy groups and siloxane chains includes 8-15 parts by mass of bisphenol A epoxy-siloxane block copolymer resin.

11. A stacked package structure, characterized by: It comprises a substrate, one or more chip stacking structures located on the substrate, and a plastic package; the chip stacking structure comprises a plurality of chips stacked in sequence; wherein the chip stacking structure is bonded to the substrate via the adhesive film described in claim 9; the chips in the chip stacking structure are bonded to each other via the adhesive film or wire adhesive film described in claim 9; the plastic package encapsulates the substrate and the one or more chip stacking structures located on the substrate.

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