Epoxy functional film easy to grind and preparation method of wafer-level chip packaging structure

Abstract

The invention provides a preparation method of an easy-to-grind epoxy functional film and a wafer-level chip packaging structure, and relates to the technical field of chip packaging, the easy-to-grind epoxy functional film comprises the following components by mass: 10-15 parts of phenoxy resin, 10-15 parts of o-cresol novolac epoxy resin, 1-4 parts of carboxyl-terminated nitrile rubber, 15-20 parts of a latent curing agent, and 1-3 parts of an accelerator. 50-52 parts of angular silica powder and 2 parts of carbon black; wherein the molecular weight of the phenoxy resin is 30000 to 35000; the phenoxy resin and the o-cresol novolac epoxy resin are used as matrix resin, the angular silica powder is used as the filler, and the carboxyl-terminated nitrile rubber, the latent curing agent and the accelerant are combined, so that the grinding efficiency of the epoxy functional film is improved, the epoxy functional film meets the working requirements of an automatic film sticking machine and a grinding machine, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip packaging, and in particular relates to a method for preparing an easy-to-grind epoxy functional film and a wafer-level chip packaging structure. Background Art

[0002] Wafer-level chip packaging (WLP) is a process for packaging and testing chips on wafers. During WLP, warping occurs due to the varying coefficients of thermal expansion of the various materials in the assembly. When warping exceeds a certain threshold, it can lead to poor soldering quality during surface mount technology (SMT) assembly, impacting subsequent redistribution layer (RDL) fabrication.

[0003] Currently, a layer of epoxy film is usually attached to the back of the wafer. After the epoxy film is cured, it can provide reverse warping to the wafer, thereby improving the RDL process. At the same time, the epoxy film also needs to be polished off. However, the polishing properties of existing epoxy films are poor, resulting in too low polishing efficiency.

[0004] Therefore, how to provide an easy-to-grind epoxy functional membrane and improve the grinding efficiency of the epoxy functional membrane by adding angular silica powder and carboxyl-terminated nitrile rubber to the epoxy system is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing an easy-to-grind epoxy functional film and a wafer-level chip packaging structure, so as to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above-mentioned purpose, the first aspect of the present invention provides an easy-to-grind epoxy functional film, which comprises the following components in parts by mass: 10-15 parts of phenoxy resin, 10-15 parts of o-cresol-type novolac epoxy resin, 1-4 parts of terminal carboxyl nitrile rubber, 15-20 parts of latent curing agent, 1-3 parts of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black; wherein the molecular weight of the phenoxy resin is 30,000-35,000.

[0007] In the first aspect, the epoxy functional film comprises the following components by mass: 12 parts of phenoxy resin, 10-13 parts of o-cresol novolac epoxy resin, 2-3 parts of carboxyl-terminated nitrile rubber, 20 parts of latent curing agent, 1 part of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black.

[0008] In the first aspect, the D50 particle size of the angular silica powder is 0.6 μm.

[0009] In the first aspect, the latent curing agent includes at least one of a naphthol curing agent and a dicyandiamide curing agent.

[0010] In the first aspect, the accelerator includes at least one of a phosphine-based curing accelerator and an imidazole-based curing accelerator.

[0011] In the first aspect, the epoxy equivalent of the o-cresol novolac epoxy resin is 180-200 g / eq.

[0012] In the first aspect, the primary particle size of the carbon black is 31 nm.

[0013] The second aspect of the present invention provides a method for preparing an easily grinded epoxy functional film, the preparation method comprising: uniformly stirring the components of the easily grinded epoxy functional film described in the first aspect to obtain a slurry; coating the slurry and drying it to obtain an easily grinded epoxy functional film.

[0014] The third aspect of the present invention provides a method for preparing a wafer-level chip packaging structure, which includes: obtaining a wafer body, and laying a semiconductor device structure and a plastic packaging material on the front of the wafer body; attaching the easy-to-grind epoxy functional film described in the first aspect to the back of the wafer body through an automatic film laminating machine, and curing it to obtain a packaged wafer; exposing the semiconductor device on the front of the packaged wafer through a laser to perform rewiring layering; and removing the easy-to-grind epoxy functional film on the back of the packaged wafer by grinding to obtain a wafer-level chip packaging structure.

[0015] In the third aspect, the curing process parameters include: curing temperature 220° C., and curing time 4 hours.

[0016] Beneficial effects: The present invention provides an easy-to-grind epoxy functional film, which comprises the following components in parts by mass: 10-15 parts of phenoxy resin, 10-15 parts of o-cresol novolac epoxy resin, 1-4 parts of carboxyl-terminated nitrile rubber, 15-20 parts of latent curing agent, 1-3 parts of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black; wherein the molecular weight of the phenoxy resin is 30,000-35,000; the phenoxy resin and o-cresol novolac epoxy resin provide the system with bonding properties and mechanical properties, and by adjusting The warpage of the epoxy functional film is adjusted by adjusting the addition ratio of o-cresol-type novolac epoxy resin; angular silica powder is used as a filler to enhance the system strength (storage modulus) and improve the grinding efficiency of the epoxy functional film; at the same time, by introducing carboxyl-terminated nitrile rubber, the impact energy of the epoxy functional film during the grinding process is absorbed, reducing the brittleness of the epoxy functional film, making it less likely to become brittle during the grinding process, forming large particles that clog the grinder gears, thereby causing current overload and causing the grinder to shut down. The present invention improves the grinding efficiency of the epoxy functional film by using phenoxy resin and o-cresol-type novolac epoxy resin as the matrix resin, angular silica powder as the filler, and combining carboxyl-terminated nitrile rubber, a latent curing agent, and an accelerator, so that it meets the working requirements of the automatic film laminating machine and the grinder, thereby improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 The present invention provides a flow chart of a method for preparing a wafer-level chip packaging structure. DETAILED DESCRIPTION

[0019] The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are for illustrating the present invention, rather than for limiting the present invention.

[0020] Throughout this specification, unless otherwise specified, the terms used herein should be understood as having the same meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In the event of any conflict, the present specification shall take precedence.

[0021] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or obtained through existing methods.

[0022] The present invention provides an easy-to-grind epoxy functional film, which comprises the following components in parts by mass: 10-15 parts of phenoxy resin, 10-15 parts of o-cresol-type novolac epoxy resin, 1-4 parts of carboxyl-terminated nitrile rubber, 15-20 parts of latent curing agent, 1-3 parts of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black; wherein the molecular weight of the phenoxy resin is 30,000-35,000.

[0023] Specifically, the present invention provides an easy-to-grind epoxy functional film, which comprises the following components in parts by mass: 10-15 parts of phenoxy resin, 10-15 parts of o-cresol novolac epoxy resin, 1-4 parts of carboxyl-terminated nitrile rubber, 15-20 parts of latent curing agent, 1-3 parts of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black; wherein the molecular weight of the phenoxy resin is 30,000-35,000; the phenoxy resin and o-cresol novolac epoxy resin provide the system with bonding properties and mechanical properties, and The warpage of the epoxy functional film is adjusted by adjusting the addition ratio of o-cresol-type novolac epoxy resin; angular silica powder is used as a filler to enhance the system strength (storage modulus) and improve the grinding efficiency of the epoxy functional film; and the introduction of carboxyl-terminated nitrile rubber absorbs the impact energy of the epoxy functional film during the grinding process, reducing the brittleness of the epoxy functional film, making it less likely to become brittle during the grinding process, forming large particles that clog the grinder gears, thereby causing current overload and causing the grinder to shut down. The present invention improves the grinding efficiency of the epoxy functional film by using phenoxy resin and o-cresol-type novolac epoxy resin as the matrix resin, angular silica powder as the filler, and combining carboxyl-terminated nitrile rubber, a latent curing agent, and an accelerator, so that it meets the working requirements of automatic film laminating machines and grinders, thereby improving production efficiency.

[0024] In some possible embodiments, the epoxy functional film includes the following components in parts by mass: 12 parts of phenoxy resin, 10-13 parts of o-cresol-type novolac epoxy resin, 2-3 parts of terminal carboxyl nitrile rubber, 20 parts of latent curing agent, 1 part of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black.

[0025] In some possible embodiments, the D50 particle size of the angular silicon powder is 0.6 μm.

[0026] Specifically, angular silica powder, due to its irregular, sharp angles, is easier to grind away after the epoxy functional film is formed, significantly improving grinding efficiency. For the same angular silica powder, the larger the particle size, the smaller the filler's specific surface area, and the relatively weaker the interface between the resin system and the filler, which easily becomes a stress concentration point, reducing the toughness of the epoxy functional film and making it easier to grind away. At the same time, by controlling the proportion of angular silica powder, the warpage of the epoxy functional film can be fine-tuned and the grinding performance of the epoxy functional film can be changed.

[0027] In some possible embodiments, the latent curing agent includes at least one of a naphthol curing agent and a dicyandiamide curing agent.

[0028] In some possible embodiments, the accelerator includes at least one of a phosphine curing accelerator and an imidazole curing accelerator.

[0029] Specifically, the combination of latent curing agent and accelerator can convert the epoxy system from rheological state to solid state and increase the reaction rate.

[0030] In some possible embodiments, the epoxy equivalent of the o-cresol novolac epoxy resin is 180-200 g / eq.

[0031] Specifically, by controlling the addition ratio of o-cresol-type novolac epoxy resin, the warping and adhesion of the epoxy functional film can be adjusted, making the epoxy functional film suitable for different scenarios.

[0032] In some possible embodiments, the primary particle size of the carbon black is 31 nm.

[0033] Based on a general inventive concept, the second aspect of the present invention provides a method for preparing an easy-to-grind epoxy functional film, the preparation method comprising: uniformly stirring the components of the easy-to-grind epoxy functional film described in the first aspect to obtain a slurry; coating the slurry and drying it to obtain an easy-to-grind epoxy functional film.

[0034] Based on a general inventive concept, please refer to Figure 1 The third aspect of the present invention provides a method for preparing a wafer-level chip packaging structure, the method comprising: (1) Obtaining a wafer body, and laying a semiconductor device structure and a molding compound on the front side of the wafer body; (2) attaching the easy-to-grind epoxy functional film described in the first aspect to the back side of the wafer body by an automatic film attaching machine and curing the film to obtain a packaged wafer; (3) exposing the semiconductor device on the front side of the packaged wafer by laser to perform redistribution layering; (4) The easy-to-grind epoxy functional film on the back side of the packaging wafer is removed by grinding to obtain a wafer-level chip packaging structure.

[0035] Specifically, the present invention provides a preparation method of an easy-to-grind epoxy functional film. First, a semiconductor device structure is laid on the front of a wafer body and sealed with a plastic molding compound, so that warping occurs toward the front of the wafer body; secondly, the dried easy-to-grind epoxy functional film is attached to the back of the wafer body by an automatic film laminating machine and cured. The high warping of the epoxy functional film drives the wafer body to warp toward the back of the wafer body, thereby correcting the warping of the front side and making the warping of the packaged wafer lower; then, the plastic molding compound on the front side of the packaged wafer is removed by laser means to expose the semiconductor device, and a wiring layer is punched to connect to the external expanded chip area; finally, the epoxy functional film on the back side of the packaged wafer is removed by a grinder to obtain a wafer-level chip packaging structure suitable for the semiconductor industry.

[0036] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are usually measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or according to the conditions recommended by the manufacturer.

[0037] The raw materials used in the examples and comparative examples are as follows: Phenoxy resin: Mitsubishi Chemical, brand JER1256; o-Cresol-type novolac epoxy resin: Jiangyin Wanqian Chemical Co., Ltd., brand NPPN-638S; Carboxyl-terminated nitrile rubber: Hubei Xinyuhong Biopharmaceutical Technology Co., Ltd., brand: 25265-19-4; Naphthol curing agent: Kenmet Materials Technology Co., Ltd., brand SN-395; Phosphine curing accelerator: triphenylphosphine (TPP); Imidazole curing accelerator: 1-cyanoethyl-2-ethyl-4-methylimidazole (2E4MZ-CN); Angular silicon powder: Jiangsu Lianrui New Materials Co., Ltd., brand NOVOPOWDER NZ; Spherical silica powder: D50=0.6μm.

[0038] Example 1 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0039] Example 2 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 10 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 52 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0040] Example 3 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 3 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0041] Example 4 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, 2E4MZ-CN: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0042] Example 5 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, dicyandiamide curing agent: 20 parts, 2E4MZ-CN: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0043] Comparative Example 1 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 25000-30000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0044] Comparative Example 2 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 35000-40000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0045] Comparative Example 3 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 52 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0046] Comparative Example 4 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 5 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0047] Comparative Example 5 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, spherical silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0048] Comparative Example 6 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 5 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, spherical silica powder: 50 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0049] Comparative Example 7 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 48 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0050] Comparative Example 8 In terms of mass fraction, the raw materials of easy-to-grind epoxy functional film include: Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type novolac epoxy resin: 13 parts, carboxyl-terminated nitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 54 parts, carbon black 3500: 2 parts; The above components are stirred evenly to obtain slurry; and the slurry is coated and dried to obtain an epoxy functional film.

[0051] The easy-to-grind epoxy functional films provided in Examples 1-5 and Comparative Examples 1-8 were tested, and the specific testing process is as follows: 1. 220℃ Silicon Wafer Adhesion Test: A 2mm×2mm 40μm thick film was transferred to the silicon wafer and cured at 150℃ for 1h. The silicon wafer was heated to 220℃ using a universal tensile testing machine. The data on the universal tensile testing machine was read and the area of ​​the epoxy functional film on the silicon wafer was measured to calculate the actual silicon wafer adhesion. 2. Tensile strength at break (film strength): After the formula is made into a slurry, it is coated into a 40μm thick film, cut into samples with a size of 10mm×55mm, and tested at 24℃ using a universal tensile testing machine at a test speed of 300mm / min. The maximum tensile strength at break is recorded and the average of three tests is taken; 3. Substrate peeling force test: After the formula is made into a slurry, it is coated into a 40μm thick film, which is then cut into samples of size 150mm×25mm. At 24°C, the film is peeled off perpendicularly to the substrate at 90°. The test is performed using a universal tensile testing machine at a test speed of 300mm / min, and the maximum stable peeling force is recorded. 4. Warpage test: After the formula is made into a slurry, it is coated into a 40μm thick film, cut into samples of size 20mm×20mm, and the light release film is torn off. The functional film is heat-transferred to a round glass sheet with a thickness of 100μm and a diameter of 10cm under the conditions of 90℃ and 2kg pressure. The heavy release film is torn off and the functional film at the edge of the glass sheet is cleanly cut. The glass sheet is placed in an oven for curing at 220℃ for 4 hours. After curing, it is naturally cooled to room temperature. After being placed at room temperature for 24 hours, the warpage of the glass sheet is measured with a steel ruler. 5. Wear resistance test: Cut the product into samples of 10cm×10cm×40μm. After curing at 150℃ / 2h, use Table Abrasion Tester to test the sheet samples according to GB / T1768-2006 method. Record the mass of the sample worn away. The result is the friction and wear mass, and take the average value of three tests.

[0052] 6. Storage Modulus Test: 40 sheets of 25μm-thick film measuring 100mm x 150mm were heat-stacked at 100°C and 2kg pressure. The sheets were then cut into 10mm x 55mm specimens and placed in a mold. The specimens were then heat-cured at 180°C for 1 hour. After heat curing, 10mm x 30mm specimens were cut for DMA storage modulus measurement. The DMA tester was used for thermal analysis, with the temperature rising from room temperature to 250°C. After the measurement, the storage modulus value at 40°C was read.

[0053] The test results are shown in Table 1 below: Table 1 Test results It should be noted that the easy-to-grind epoxy functional film provided by the present invention will be used in an automatic film laminating machine during application, and its normal operational requirements are: a. The tensile strength at break is in the range of 140-220gf / 10mm; b. The peeling force on the substrate is in the range of 20-35gf / 25mm; c. The adhesion to the silicon wafer at 220°C is required to be no less than 5MPa; d. When tested using a Table abrasion tester, the friction and wear mass must be greater than 40mg to prevent the client grinder current from exceeding 20A and causing an alarm or shutdown.

[0054] From the above table we can see that: (1) The epoxy functional film prepared using the formula ratios of Examples 1-5 can meet the working requirements of the automatic film laminating machine and the grinding machine, thereby improving production efficiency; (2) In Comparative Example 1, a phenoxy resin with a molecular weight of 25,000-30,000 was used. The epoxy functional film prepared therefrom had a low tensile strength at break and a high peeling force on the substrate, which could not meet the working requirements of the automatic film laminating machine. In Comparative Example 2, a phenoxy resin with a molecular weight of 35,000-40,000 was used. The epoxy functional film prepared therefrom had a low adhesion to the silicon wafer and was easily separated from the wafer, affecting the normal operation of subsequent devices. (3) In Comparative Example 3, no carboxyl-terminated nitrile rubber was used, and the epoxy functional film prepared therefrom stopped the grinder due to current overload during the grinding process; and in Comparative Example 4, the amount of carboxyl-terminated nitrile rubber added was too high, resulting in a large tensile strength at break, making it unsuitable for automatic film laminating machines; (4) Comparative Examples 5 and 6 both used spherical silicon powder as a filler. The epoxy functional films prepared therefrom caused the grinding machine to stop due to current overload during the grinding process. (5) In Comparative Example 7, the amount of angular silicon powder added is relatively low, and the tensile strength at break of the epoxy functional film prepared therefrom is relatively low; whereas in Comparative Example 8, the amount of angular silicon powder added is relatively high, and the tensile strength at break of the epoxy functional film prepared therefrom is relatively high, so that the epoxy functional films prepared therefrom in Comparative Examples 7 and 8 cannot be operated using an automatic film laminating machine.

[0055] In summary, the epoxy functional film prepared using the specific formula ratio of this application has excellent grinding efficiency and meets the working requirements of the automatic film laminating machine and the grinding machine, thereby improving production efficiency.

[0056] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0057] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0058] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. An easy-to-grind epoxy functional film, characterized in that: The epoxy functional film comprises the following components in parts by mass: 10-15 parts of phenoxy resin, 10-15 parts of o-cresol novolac epoxy resin, 1-4 parts of carboxyl-terminated nitrile rubber, 15-20 parts of latent curing agent, 1-3 parts of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black; wherein the molecular weight of the phenoxy resin is 30,000-35,000.

2. The easy-to-grind epoxy functional film according to claim 1, characterized in that: The epoxy functional film comprises the following components by mass: 12 parts of phenoxy resin, 10-13 parts of o-cresol novolac epoxy resin, 2-3 parts of carboxyl-terminated nitrile rubber, 20 parts of latent curing agent, 1 part of accelerator, 50-52 parts of angular silica powder and 2 parts of carbon black.

3. The easy-to-grind epoxy functional film according to claim 2, characterized in that: The D50 particle size of the angular silicon powder is 0.6 μm.

4. The easy-to-grind epoxy functional film according to claim 2, characterized in that: The latent curing agent includes at least one of a naphthol curing agent and a dicyandiamide curing agent.

5. The easy-to-grind epoxy functional film according to claim 2, characterized in that: The accelerator includes at least one of a phosphine curing accelerator and an imidazole curing accelerator.

6. The easy-to-grind epoxy functional film according to claim 2, characterized in that: The epoxy equivalent of the o-cresol novolac epoxy resin is 180-200 g / eq.

7. The easy-to-grind epoxy functional film according to claim 2, characterized in that: The primary particle size of the carbon black is 31 nm.

8. A method for preparing an easily grindable epoxy functional film, characterized in that: The preparation method comprises: Stirring the components of the easy-to-grind epoxy functional film according to any one of claims 1 to 7 to obtain a slurry; The slurry is coated and dried to obtain an easily grinded epoxy functional film.

9. A method for preparing a wafer-level chip packaging structure, characterized in that: The preparation method comprises: Obtaining a wafer body, and laying a semiconductor device structure and a molding compound on the front side of the wafer body; The easy-to-grind epoxy functional film according to any one of claims 1 to 7 is attached to the back side of the wafer body by an automatic film attaching machine, and cured to obtain a packaged wafer; Exposing the semiconductor devices on the front side of the packaged wafer by laser for redistribution layering; The easy-to-grind epoxy functional film on the back side of the packaging wafer is removed by grinding to obtain a wafer-level chip packaging structure.

10. The method for preparing a wafer-level chip packaging structure according to claim 9, wherein: The curing process parameters include: curing temperature of 220° C. and curing time of 4 hours.

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