A method for preparing an easily-grinding epoxy functional film and wafer-level chip packaging structure

Abstract

The application provides a preparation method of a wafer-level chip packaging structure and an easy-to-grind epoxy functional film, and relates to the technical field of chip packaging.The easy-to-grind epoxy functional film comprises, in mass fraction, 10-15 parts of phenoxy resin, 10-15 parts of o-cresol type phenolic epoxy resin, 1-4 parts of carboxyl-terminated butylnitrile rubber, 15-20 parts of latent curing agent, 1-3 parts of accelerator, 50-52 parts of angular silicon micro powder and 2 parts of carbon black; wherein the molecular weight of the phenoxy resin is 30000-35000; the epoxy functional film has improved grinding efficiency by using the phenoxy resin and the o-cresol type phenolic epoxy resin as the base resin, the angular silicon micro powder as the filler, and in combination with the carboxyl-terminated butylnitrile rubber, the latent curing agent and the accelerator, so that the working requirements of the automatic film laminator and the grinding machine are met, thereby improving the production efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of chip packaging, and particularly relates to an easy-to-grind epoxy functional film and a preparation method of a wafer-level chip packaging structure. BACKGROUND

[0002] Wafer-level chip packaging is a process of packaging and testing chips on a wafer. During the wafer-level chip packaging process, warping occurs due to the different thermal expansion coefficients of various materials in the components, and when the warping exceeds a certain amplitude, the soldering quality of surface mount technology (SMT) is poor, which affects the subsequent redistribution layer (RDL) process.

[0003] At present, an epoxy film is usually attached to the back of the wafer, and 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 ground and removed. However, the existing epoxy film has poor grindability, resulting in too low grinding efficiency.

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

[0005] The present application aims to provide an easy-to-grind epoxy functional film and a preparation method of a wafer-level chip packaging structure to at least solve the above technical problems.

[0006] To achieve the above-mentioned purpose, the present application provides an easy-to-grind epoxy functional film in the first aspect, which comprises the following components in mass fraction: phenoxy resin 10-15 parts, o-cresol type phenolic epoxy resin 10-15 parts, carboxyl-terminated nitrile rubber 1-4 parts, latent curing agent 15-20 parts, accelerator 1-3 parts, angular silicon powder 50-52 parts and carbon black 2 parts; wherein the molecular weight of the phenoxy resin is 30000-35000.

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

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

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

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

[0011] In the first aspect, the o-cresol type phenolic epoxy resin has an epoxy equivalent weight of 180-200 g / eq.

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

[0013] The second aspect of the present application provides a preparation method of the easily-grinded epoxy functional film, which comprises: uniformly stirring the components in the easily-grinded epoxy functional film of the first aspect to obtain a slurry; coating and drying the slurry to obtain the easily-grinded epoxy functional film.

[0014] The third aspect of the present application provides a preparation method of a wafer-level chip packaging structure, which comprises: obtaining a wafer body, and laying a semiconductor device structure and a plastic sealing material on the front surface of the wafer body; attaching the easily-grinded epoxy functional film of the first aspect to the back surface of the wafer body by an automatic film attaching machine, and curing to obtain a packaged wafer; exposing the semiconductor device on the front surface of the packaged wafer by laser to perform a redistribution layer; and removing the easily-grinded epoxy functional film on the back surface of the packaged wafer by grinding to obtain the wafer-level chip packaging structure.

[0015] In the third aspect, the curing process parameters comprise: a curing temperature of 220℃ and a curing time of 4h.

[0016] Advantages:

[0017] The application provides an easy-to-grind epoxy functional film, which comprises the following components in mass fraction: phenoxy resin 10-15 parts, o-cresol type phenolic epoxy resin 10-15 parts, carboxyl-terminated butyl nitrile rubber 1-4 parts, latent curing agent 15-20 parts, accelerator 1-3 parts, angular silicon micro powder 50-52 parts and carbon black 2 parts; wherein the molecular weight of the phenoxy resin is 30000-35000; the phenoxy resin and the o-cresol type phenolic epoxy resin are used to provide the bonding property and the mechanical property of the system, and the warpage of the epoxy functional film is adjusted by adjusting the adding proportion of the o-cresol type phenolic epoxy resin; the angular silicon micro powder is used as a filler, which can not only enhance the strength (storage modulus) of the system, but also improve the grinding efficiency of the epoxy functional film; meanwhile, the carboxyl-terminated butyl nitrile rubber is introduced to absorb the impact energy of the epoxy functional film in the grinding process, reduce the brittleness of the epoxy functional film, so that the epoxy functional film is not easy to be brittle and form large particle substances in the grinding process, thereby blocking the gear of the grinding machine, resulting in current overload and causing the grinding machine to stop. The application uses the phenoxy resin and the o-cresol type phenolic epoxy resin as the base resin, the angular silicon micro powder as the filler, and combines the carboxyl-terminated butyl nitrile rubber, the latent curing agent and the accelerator, so that the grinding efficiency of the epoxy functional film is improved, and the working requirements of the automatic film sticking machine and the grinding machine are met, thereby improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative effort.

[0019] Figure 1 A flow chart of a preparation method of a wafer level chip package structure is provided. DETAILED DESCRIPTION

[0020] The advantages and various effects of the present application will be more clearly presented by the following specific embodiments and examples. Those skilled in the art should understand that these specific embodiments and examples are used to illustrate the present application, not to limit the present application.

[0021] Throughout the specification, unless otherwise specifically indicated, the terms used herein are to be understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as generally understood by those skilled in the art to which the present application belongs. If there is a conflict, the present specification takes precedence.

[0022] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be obtained by purchasing them from the market or by existing methods.

[0023] The present invention provides an easy-to-grind epoxy functional film, wherein the epoxy functional film comprises the following components by weight: 10-15 parts of phenoxy resin, 10-15 parts of o-cresol-type phenolic epoxy resin, 1-4 parts of carboxyl-terminated butadiene-acrylonitrile 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 phenoxy resin is 30,000-35,000.

[0024] Specifically, the present invention provides an easily grindable epoxy functional film, comprising the following components by weight: 10-15 parts phenoxy resin, 10-15 parts o-cresol-type phenolic epoxy resin, 1-4 parts carboxyl-terminated butadiene-acrylonitrile rubber, 15-20 parts latent curing agent, 1-3 parts accelerator, 50-52 parts angular silica powder, and 2 parts carbon black; wherein the molecular weight of the phenoxy resin is 30,000-35,000; the phenoxy resin and o-cresol-type phenolic epoxy resin provide the system with adhesive and mechanical properties, and The warpage of the epoxy functional film is adjusted by modifying the addition ratio of o-cresol-type phenolic epoxy resin. Using angular silica powder as a filler enhances both the system strength (storage modulus) and the grinding efficiency of the epoxy functional film. Simultaneously, the introduction of carboxyl-terminated nitrile rubber absorbs the impact energy of the epoxy functional film during grinding, reducing its brittleness and preventing it from crumbling into large particles that clog the grinding machine gears, leading to current overload and machine shutdown. This invention improves the grinding efficiency of the epoxy functional film by using phenoxy resin and o-cresol-type phenolic 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, thus meeting the working requirements of automatic laminating machines and grinding machines, thereby increasing production efficiency.

[0025] In some possible embodiments, the epoxy functional film comprises, by weight, the following components: 12 parts phenoxy resin, 10-13 parts o-cresol phenolic epoxy resin, 2-3 parts carboxyl-terminated nitrile rubber, 20 parts latent curing agent, 1 part accelerator, 50-52 parts angular silica powder, and 2 parts carbon black.

[0026] In some possible embodiments, the D50 particle size of the angular silica powder is 0.6 μm.

[0027] Specifically, angular silica powder, due to its irregular sharp angles, is more easily ground off after the epoxy functional film is fabricated, which can greatly improve grinding efficiency. For the same angular silica powder, the larger the particle size, the smaller the specific surface area of ​​the filler, and the relatively weaker the interfacial bonding between the resin system and the filler. This makes it easier to become a stress concentration point, reducing the toughness of the epoxy functional film and making it easier to grind off. At the same time, by controlling the proportion of angular silica powder, the warpage of the epoxy functional film can be finely adjusted and its grinding performance can be changed.

[0028] In some possible embodiments, the latent curing agent includes at least one of naphthol curing agents and dicyandiamide curing agents.

[0029] In some possible embodiments, the accelerator includes at least one of phosphine-based curing accelerators and imidazole-based curing accelerators.

[0030] Specifically, the combination of latent curing agents and accelerators can transform epoxy systems from a rheological state to a solid state and increase the reaction rate.

[0031] In some possible embodiments, the epoxy equivalent of the o-cresol-type phenolic epoxy resin is 180-200 g / eq.

[0032] Specifically, by controlling the addition ratio of o-cresol-type phenolic epoxy resin, the warpage and adhesion of epoxy functional films can be adjusted, thus making epoxy functional films suitable for different scenarios.

[0033] In some possible embodiments, the primary particle size of the carbon black is 31 nm.

[0034] Based on a general inventive concept, the second aspect of the present invention provides a method for preparing an easily grindable epoxy functional film, the method comprising: stirring each component of the easily grindable epoxy functional film described in the first aspect evenly to obtain a slurry; coating the slurry and drying it to obtain an easily grindable epoxy functional film.

[0035] Based on a general inventive concept, please refer to... Figure 1 The third aspect of the present invention provides a method for fabricating a wafer-level chip packaging structure, the method comprising:

[0036] (1) Obtain a wafer body and lay semiconductor device structures and molding compound on the front side of the wafer body;

[0037] (2) The easily polishable epoxy functional film described in the first aspect is attached to the back of the wafer body by an automatic film attaching machine and then cured to obtain a packaged wafer;

[0038] (3) Expose the semiconductor devices on the front side of the packaged wafer by laser to perform redistribution fabrication;

[0039] (4) The easily polishable epoxy functional film on the back side of the packaged wafer is removed by grinding to obtain a wafer-level chip packaging structure.

[0040] Specifically, the present invention provides a method for preparing an easily grindable epoxy functional film. First, a semiconductor device structure is deposited on the front side of a wafer body and sealed with molding compound, causing warping towards the front side of the wafer body. Second, a dried easily grindable epoxy functional film is applied to the back side of the wafer body using an automatic laminator and cured. The high warpage of the epoxy functional film causes the wafer body to warp towards the back side, thereby correcting the front warpage and resulting in a lower warpage of the packaged wafer. Then, the molding compound on the front side of the packaged wafer is removed using a laser to expose the semiconductor device, and wiring layers are punched to connect to and expand the chip area. Finally, the epoxy functional film on the back side of the packaged wafer is removed using a grinding machine, thereby obtaining a wafer-level chip packaging structure suitable for the semiconductor industry.

[0041] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0042] The raw materials used in the examples and comparative examples are as follows:

[0043] Phenoxy resin: Mitsubishi Chemical, grade JER1256;

[0044] o-Cresol-type phenolic epoxy resin: Jiangyin Wanqian Chemical Co., Ltd., brand name NPPN-638S;

[0045] Carboxyl-terminated nitrile butadiene rubber: Hubei Xinyuhong Biomedical Technology Co., Ltd., Grade: 25265-19-4;

[0046] Naphthol curing agent: Kenmet Materials Technology Co., Ltd., grade SN-395;

[0047] Phosphine-based curing accelerator: Triphenylphosphine (TPP);

[0048] Imidazole curing accelerator: 1-Cyanoethyl-2-ethyl-4-methylimidazolium (2E4MZ-CN);

[0049] Angular silica powder: Jiangsu Lianrui New Materials Co., Ltd., brand name NOVOPOWDER NZ;

[0050] Spherical silica powder: D50=0.6μm.

[0051] Example 1

[0052] By weight, the raw materials for easily grindable epoxy functional films include:

[0053] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts.

[0054] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0055] Example 2

[0056] By weight, the raw materials for easily grindable epoxy functional films include:

[0057] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 10 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 52 parts, carbon black 3500: 2 parts.

[0058] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0059] Example 3

[0060] By weight, the raw materials for easily grindable epoxy functional films include:

[0061] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 3 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts.

[0062] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0063] Example 4

[0064] By weight, the raw materials for easily grindable epoxy functional films include:

[0065] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, 2E4MZ-CN: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts.

[0066] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0067] Example 5

[0068] By weight, the raw materials for easily grindable epoxy functional films include:

[0069] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, dicyandiamide curing agent: 20 parts, 2E4MZ-CN: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts.

[0070] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0071] Comparative Example 1

[0072] By weight, the raw materials for easily grindable epoxy functional films include:

[0073] Phenoxy resin (molecular weight Mw: 25000-30000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts.

[0074] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0075] Comparative Example 2

[0076] By weight, the raw materials for easily grindable epoxy functional films include:

[0077] Phenoxy resin (molecular weight Mw: 35000-40000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts.

[0078] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0079] Comparative Example 3

[0080] By weight, the raw materials for easily grindable epoxy functional films include:

[0081] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 52 parts, carbon black 3500: 2 parts.

[0082] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0083] Comparative Example 4

[0084] By weight, the raw materials for easily grindable epoxy functional films include:

[0085] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 5 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 50 parts, carbon black 3500: 2 parts.

[0086] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0087] Comparative Example 5

[0088] By weight, the raw materials for easily grindable epoxy functional films include:

[0089] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, spherical silica powder: 50 parts, carbon black 3500: 2 parts.

[0090] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0091] Comparative Example 6

[0092] By weight, the raw materials for easily grindable epoxy functional films include:

[0093] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 5 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, spherical silica powder: 50 parts, carbon black 3500: 2 parts.

[0094] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0095] Comparative Example 7

[0096] By weight, the raw materials for easily grindable epoxy functional films include:

[0097] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 48 parts, carbon black 3500: 2 parts.

[0098] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0099] Comparative Example 8

[0100] By weight, the raw materials for easily grindable epoxy functional films include:

[0101] Phenoxy resin (molecular weight Mw: 30000-35000): 12 parts, o-cresol type phenolic epoxy resin: 13 parts, carboxyl-terminated butadiene-acrylonitrile rubber: 2 parts, naphthol curing agent: 20 parts, triphenylphosphine: 1 part, angular silica powder: 54 parts, carbon black 3500: 2 parts.

[0102] The above components are stirred evenly to obtain a slurry; the slurry is then coated and dried to obtain an epoxy functional film.

[0103] The easily grindable epoxy functional films provided in Examples 1-5 and Comparative Examples 1-8 were tested, and the specific test procedures are as follows:

[0104] 1. Test of silicon wafer adhesion at 220℃: A 2mm×2mm film with a thickness of 40μm was transferred onto a silicon wafer. After curing at 150℃ for 1 hour, 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.

[0105] 2. Tensile strength at break (film strength): After the formula is made into a slurry, it is coated into a film with a thickness of 40μm, cut into samples with a size of 10mm×55mm, and tested with a universal tensile testing machine at 24℃ and a testing speed of 300mm / min. The maximum tensile strength at break is recorded, and the average value of three tests is taken.

[0106] 3. Peel strength test on substrate: After the formula is made into a slurry, it is coated into a 40μm thick film and cut into samples of 150mm×25mm. Under the condition of 24℃, the film is peeled at 90° perpendicular to the substrate and tested with a universal tensile testing machine at a test speed of 300mm / min. The maximum stable peel strength is recorded.

[0107] 4. Warpage Test: After the formula is made into a slurry, it is coated into a 40μm thick film and cut into 20mm×20mm sample pieces. The light release film is peeled off, and the functional film is heat-transferred onto a 100μm thick and 10cm diameter round glass slide under 90℃ / 2kg pressure. The heavy release film is peeled off, and the functional film at the edge of the glass slide is cleaned. The slide is placed in an oven and cured at 220℃ / 4h. After curing, it is allowed to cool naturally to room temperature. After being left at room temperature for 24h, the warpage of the glass slide is measured with a steel ruler.

[0108] 5. Abrasion resistance test: Cut the product into 10cm×10cm×40μm samples, cure at 150℃ / 2h, and use a Table abrasion tester to test the sheet samples according to the method of GB / T1768-2006. Record the mass of the sample worn away, and the result is the friction and wear mass. Take the average value of three tests.

[0109] 6. Storage Modulus Test: Forty 25μm thick films (100mm × 150mm) were heat-bonded and transferred to thick sheets under 100℃ / 2kg pressure. These were then cut into 10mm × 55mm samples and placed in a mold, followed by curing at 180℃ for 1 hour. After heat curing, 10mm × 30mm samples were cut as samples for measuring the DMA storage modulus. The DMA testing instrument was heated from room temperature to 250℃ for thermal analysis. After measurement, the storage modulus value at 40℃ was read.

[0110] The test results are shown in Table 1 below:

[0111] Table 1 Test Results

[0112]

[0113] It should be further noted that the easy-to-grind epoxy functional film provided by this invention will be used with an automatic laminating machine. Its normal operation requirements are: a) tensile strength at break is in the range of 140-220 gf / 10 mm; b) peel force to substrate is in the range of 20-35 gf / 25 mm; c) adhesion to silicon wafer at 220℃ is not less than 5 MPa; d) when tested with a Table abrasion meter, the frictional wear mass must be greater than 40 mg to prevent the client's grinding machine current from exceeding 20 A and triggering an alarm and shutdown.

[0114] As can be seen from the table above:

[0115] (1) The epoxy functional film prepared using the formulation ratios of Examples 1-5 can meet the working requirements of automatic laminating machines and grinding machines, thereby improving production efficiency;

[0116] (2) In Comparative Example 1, phenoxy resin with a molecular weight of 25,000-30,000 was used. The epoxy functional film prepared by it had a low tensile strength at break and a high peel force to the substrate, which could not meet the working requirements of the automatic film applicator. In Comparative Example 2, phenoxy resin with a molecular weight of 35,000-40,000 was used. The epoxy functional film prepared by it had a low silicon wafer adhesion and was easy to separate from the wafer, which affected the normal operation of subsequent devices.

[0117] (3) In Comparative Example 3, no carboxyl-terminated nitrile rubber was used. The epoxy functional film prepared there caused the grinding machine to stop due to current overload during the grinding process. In Comparative Example 4, the amount of carboxyl-terminated nitrile rubber added was too high, resulting in a large tensile strength at break, which is not suitable for automatic film applicators.

[0118] (4) Both Comparative Example 5 and Comparative Example 6 used spherical silicon micro powder as filler. The epoxy functional film prepared by them caused the grinding machine to stop due to current overload during the grinding process.

[0119] (5) The amount of angular silicon powder added in Comparative Example 7 was relatively low, and the tensile strength of the epoxy functional film prepared by it was relatively low; while the amount of angular silicon powder added in Comparative Example 8 was relatively high, and the tensile strength of the epoxy functional film prepared by it was relatively high, so the epoxy functional films prepared by Comparative Example 7 and Comparative Example 8 could not be operated by an automatic film laminating machine.

[0120] In summary, only epoxy functional films prepared using the specific formulation ratio of this application have excellent grinding efficiency and meet the working requirements of automatic laminators and grinders, thereby improving production efficiency.

[0121] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises 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.

[0122] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0123] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An easily grindable epoxy functional film, characterized in that, The epoxy functional film comprises the following components by weight: 10-15 parts phenoxy resin, 10-15 parts o-cresol phenolic epoxy resin, 1-4 parts carboxyl-terminated butadiene-acrylonitrile rubber, 15-20 parts latent curing agent, 1-3 parts accelerator, 50-52 parts angular silica powder, and 2 parts carbon black; wherein the weight average molecular weight of the phenoxy resin is 30,000-35,000. The angular silica micropowder has a D50 particle size of 0.6 μm.

2. The easily grindable epoxy functional film according to claim 1, characterized in that, The epoxy functional film comprises the following components by weight: 12 parts phenoxy resin, 10-13 parts o-cresol type phenolic epoxy resin, 2-3 parts carboxyl-terminated butadiene-acrylonitrile rubber, 20 parts latent curing agent, 1 part accelerator, 50-52 parts angular silica powder, and 2 parts carbon black.

3. The easily grindable epoxy functional film according to claim 2, characterized in that, The latent curing agent includes at least one of naphthol curing agents and dicyandiamide curing agents.

4. The easily grindable epoxy functional film according to claim 2, characterized in that, The accelerator includes at least one of phosphine-based curing accelerators and imidazole-based curing accelerators.

5. The easily grindable epoxy functional membrane according to claim 2, characterized in that, The epoxy equivalent of the o-cresol-type phenolic epoxy resin is 180-200 g / eq.

6. The easily grindable epoxy functional film according to claim 2, characterized in that, The original particle size of the carbon black is 31 nm.

7. A method for preparing an easily grindable epoxy functional film, characterized in that, The preparation method includes: The components of the easily grindable epoxy functional membrane according to any one of claims 1-6 are stirred evenly to obtain a slurry; The slurry is coated and dried to obtain an easy-to-grind epoxy functional film.

8. A method for fabricating a wafer-level chip packaging structure, characterized in that, The preparation method includes: Obtain a wafer body, and lay semiconductor device structures and molding compound on the front side of the wafer body; The easily grindable epoxy functional film according to any one of claims 1-6 is applied to the back side of the wafer body using an automatic film application machine and then cured to obtain an encapsulated wafer. The semiconductor devices on the front side of the packaged wafer are exposed by laser to perform redistribution fabrication layers; The easily polishable epoxy functional film on the back side of the packaged wafer is removed by grinding to obtain a wafer-level chip packaging structure.

9. The method for fabricating a wafer-level chip packaging structure according to claim 8, characterized in that, The curing process parameters include: curing temperature 220℃, curing time 4h.

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