Low-warpage low-viscosity liquid molding compound, preparation method thereof and chip packaging method

Abstract

The invention provides a low-warpage low-viscosity liquid molding compound, a preparation method thereof and a chip packaging method. The liquid molding compound comprises the following components in parts by mass: 80-90 parts of a filling agent, 1.5-4.5 parts of first epoxy resin, 10-15 parts of a mixture, 1-3 parts of a curing agent, 0.2-0.5 part of an accelerant and 0.1-0.3 part of a coloring agent, wherein the mixture is formed by compounding second epoxy resin and silica powder, the mass ratio of the second epoxy resin to the silica powder is 60%: 40%, and the second epoxy resin is the same as the first epoxy resin; the second epoxy resin and the silica powder are compounded according to the mass ratio of 60%: 40% to prepare the mixture, so that the silica powder can be fully dispersed in the second epoxy resin, the compatibility of the silica powder with the filler and the first epoxy resin is improved, the gap between the filler and the silica powder is reduced, and the viscosity, thixotropy and warpage of the glue solution are further reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor chip packaging, and particularly relates to a low-warpage and low-viscosity liquid mold sealant and a preparation method thereof, and a chip packaging method. Background Art

[0002] From smartphones to smart driving, from 5G networks to the AI ​​era, with the increasing development of intelligent production and lifestyle, the industry applications of semiconductors are almost everywhere. The bonding technology of semiconductor packaging plays an important role in the miniaturization, multi-functionality, higher reliability and low cost of semiconductors.

[0003] In traditional wafer packaging, the finished wafer is cut into individual chips, and then bonded and packaged. In wafer-level packaging, the wafer is packaged first, and the protective layer can be bonded to the top or bottom of the wafer, and then the circuit is connected, and the wafer is cut into individual chips, so that the size of the packaged chip is close to or even equal to the size of the bare die on the wafer. However, due to the difference in thermal expansion coefficient between the packaging material and the substrate or chip during the curing process, the packaging material will warp after curing, affecting the wafer cutting process.

[0004] Therefore, how to provide a liquid mold sealant with low warpage and low viscosity, by preparing a mixture of silicon micropowder and epoxy resin, improving the compatibility of the filler and epoxy resin, and then reducing the warpage of the material, is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The object of the present invention is to provide a low-warpage and low-viscosity liquid mold sealant and a preparation method thereof, and a chip packaging method, so as to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above-mentioned object, the first aspect of the present invention provides a low-warpage and low-viscosity liquid mold sealant, which comprises the following components, measured by mass: 80 to 90 parts of a filler, 1.5 to 4.5 parts of a first epoxy resin, 10 to 15 parts of a mixture, 1 to 3 parts of a curing agent, 0.2 to 0.5 parts of an accelerator, and 0.1 to 0.3 parts of a colorant; wherein the mixture is compounded from a second epoxy resin and silicon micropowder, the mass ratio of the second epoxy resin to the silicon micropowder is 60%:40%, and the second epoxy resin is the same as the first epoxy resin.

[0007] In the first aspect, both the first epoxy resin and the second epoxy resin are low-viscosity epoxy resins, and the viscosity of the low-viscosity epoxy resin is less than 1.5 Pa·s.

[0008] In the first aspect, the particle size D100 of the silicon powder is 40 to 60 nm.

[0009] In the first aspect, the filler includes silicon dioxide, and the particle size D99 of the silicon dioxide is 25 to 30 μm.

[0010] In the first aspect, the curing agent is an alicyclic amine curing agent, and the alicyclic amine curing agent includes 1,3-bis(aminomethyl)cyclohexane.

[0011] In the first aspect, the accelerator is a latent accelerator, and the latent accelerator includes 1-ethylimidazole.

[0012] In the first aspect, the coloring agent comprises carbon black.

[0013] The second aspect of the present invention provides a method for preparing a low-warpage and low-viscosity liquid mold sealant as described in the first aspect, the preparation method comprising: preparing a mixture by a high-shear homogenizer, the mixture being compounded by a second epoxy resin and silicon micropowder, the mass ratio of the second epoxy resin to the silicon micropowder being 60%:40%; accurately weighing each component of the raw material, the components specifically comprising, by mass, 80 to 90 parts of a filler, 1.5 to 4.5 parts of a first epoxy resin, 10 to 15 parts of a mixture, 1 to 3 parts of a curing agent, 0.2 to 0.5 parts of an accelerator, and 0.1 to 0.3 parts of a dye; wherein the second epoxy resin is the same as the first epoxy resin; weighing the first The epoxy resin, the mixture, the curing agent and the dye are added to a stirring cup and stirred evenly to obtain a first slurry; the weighed filler is divided into three equal parts, the first part of the filler is added to the stirring cup and stirred evenly; the second part of the filler is continued to be added to the stirring cup and stirred evenly; the third part of the filler is continued to be added to the stirring cup and stirred evenly to obtain a second slurry; the second slurry is transferred to a three-roll grinder for dispersion treatment to obtain a uniformly dispersed third slurry; the accelerator is added to the third slurry and stirred evenly to obtain a fourth slurry; the fourth slurry is vacuum degassed by a centrifugal mixer to obtain a liquid mold sealant.

[0014] In the second aspect, the working parameters of the three-roll mill include: the feeding gap is 70-100 μm, and the discharging gap is 40-60 μm; the working parameters of the centrifugal mixer include: vacuum degassing time is 60-120 s, rotation is 120 r / min, and revolution is 1200 r / min.

[0015] The third aspect of the present invention provides a chip packaging method, which includes: obtaining a wafer body; coating the low-warpage and low-viscosity liquid mold sealing glue described in the first aspect on the wafer body, and curing it to obtain a packaged wafer; cutting the packaged wafer to obtain a number of well-packaged chips.

[0016] Beneficial effects: The present invention provides a low-warpage and low-viscosity liquid mold sealant, which comprises the following components by mass: 80-90 parts of a filler, 1.5-4.5 parts of a first epoxy resin, 10-15 parts of a mixture, 1-3 parts of a curing agent, 0.2-0.5 parts of an accelerator, and 0.1-0.3 parts of a dye; wherein the mixture is compounded by a second epoxy resin and silicon micropowder, the mass ratio of the second epoxy resin to the silicon micropowder is 60%:40%, and the second epoxy resin is the same as the first epoxy resin; First, the second epoxy resin and silicon micropowder are compounded in a mass ratio of 60%:40% to prepare a mixture, so that the silicon micropowder can be fully dispersed in the second epoxy resin, the compatibility of the silicon micropowder with the filler and the first epoxy resin is improved, the gap between the filler and the silicon micropowder is reduced, and the viscosity, thixotropy and warping of the glue are reduced; at the same time, the glue is cured into a film in combination with a curing agent and an accelerator, and the film is marked with a dye to form a liquid mold sealant that can be used to encapsulate the wafer. The present invention improves the compatibility between the raw material components by pre-preparing a compound mixture of the second epoxy resin and silicon micropowder, reduces the gap between the filler and the silicon micropowder, thereby reducing the viscosity and thixotropy of the glue, so that the glue has a better leveling effect and has a lower warping after curing. 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 drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0018] Figure 1 A flow chart of a method for preparing a low-warpage and low-viscosity liquid mold sealant provided by the present invention; Figure 2 This is a photo of the polished wafer viewed under a microscope in Comparative Example 5 provided by the present invention; Figure 3 This is a picture showing the effect of the wafer in Example 1 provided by the present invention after polishing when viewed under a microscope. DETAILED DESCRIPTION

[0019] The present invention will be described in detail below in conjunction with specific implementations 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 implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0020] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes 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 by existing methods.

[0022] The present invention provides a low-warpage and low-viscosity liquid mold sealant, which comprises the following components in parts by mass: 80 to 90 parts of a filler, 1.5 to 4.5 parts of a first epoxy resin, 10 to 15 parts of a mixture, 1 to 3 parts of a curing agent, 0.2 to 0.5 parts of an accelerator, and 0.1 to 0.3 parts of a colorant; wherein the mixture is compounded from a second epoxy resin and silicon micropowder, the mass ratio of the second epoxy resin to the silicon micropowder is 60%:40%, and the second epoxy resin is the same as the first epoxy resin.

[0023] Specifically, the present invention provides a low-warpage and low-viscosity liquid mold sealant, which includes the following components by mass: 80-90 parts of filler, 1.5-4.5 parts of first epoxy resin, 10-15 parts of mixture, 1-3 parts of curing agent, 0.2-0.5 parts of accelerator, and 0.1-0.3 parts of dye; wherein the mixture is compounded by a second epoxy resin and silicon micropowder, the mass ratio of the second epoxy resin to the silicon micropowder is 60%:40%, and the second epoxy resin and the first epoxy resin are The same; first, the second epoxy resin and the silicon micropowder are compounded in a mass ratio of 60%:40% to prepare a mixture, so that the silicon micropowder can be fully dispersed in the second epoxy resin, the compatibility of the silicon micropowder with the filler and the first epoxy resin is improved, and the gap between the filler and the silicon micropowder is reduced, thereby reducing the viscosity, thixotropy and warping of the glue; at the same time, the glue is cured into a film in combination with a curing agent and an accelerator, and the film is marked with a dye to form a liquid mold sealant that can be used to encapsulate the wafer. The present invention improves the compatibility between the raw material components by pre-preparing a compounded mixture of the second epoxy resin and the silicon micropowder, reduces the gap between the filler and the silicon micropowder, thereby reducing the viscosity and thixotropy of the glue, so that the glue has a better leveling effect and has a lower warping after curing.

[0024] In some possible embodiments, both the first epoxy resin and the second epoxy resin are low-viscosity epoxy resins, and the viscosity of the low-viscosity epoxy resin is less than 1.5 Pa·s.

[0025] This is because the first epoxy resin and the second epoxy resin are selected from low-viscosity epoxy resins with a viscosity of less than 1.5 Pa·s, which can improve the dispersibility of the filler in the epoxy resin. When the silicon micropowder is mixed with the second epoxy resin, the viscosity of the material can also be reduced. The epoxy resin can be any one of a phenolic epoxy resin, an amino tetrafunctional epoxy resin, an aminophenol trifunctional epoxy resin, a bisphenol S epoxy resin, a bisphenol A epoxy resin, a bisphenol F epoxy resin, a silicon-containing epoxy resin, and a hexafunctional epoxy resin. Preferably, the epoxy resin is a bisphenol F epoxy resin, and its model is ZLF-160U.

[0026] In some possible embodiments, the particle size D100 of the silicon micropowder is 40-60 nm.

[0027] Those skilled in the art will understand that the particle size D100 of the silicon micropowder is 40 to 60 nm. The silicon micropowder is first mixed with the epoxy resin, and then the mixture is mixed with the large-particle filler, which can improve the dispersibility of the small-particle silicon micropowder in the large-particle filler, and the epoxy resin can also be fully filled in the silicon micropowder. Preferably, the particle size D100 of the silicon micropowder is 50 nm. In some possible embodiments, the filler includes silicon dioxide, and the particle size D99 of the silicon dioxide is 25-30 μm.

[0028] This is because, when the same type of silica is used alone as a filling material, although it can reduce the thermal expansion coefficient and warpage of the resin material, the large-particle silica has poor dispersibility in the resin material and large warpage, and is not suitable for packaging large-size wafers. Therefore, two filling materials with different particle sizes are used to improve the dispersibility. First, small-particle silicon powder and epoxy resin are mixed at high speed to prepare a uniformly dispersed and fully fused mixture, and then the mixture is mixed with large-particle silicon dioxide, so that the epoxy resin can be fully filled in the gap between the large-particle silicon dioxide and the small-particle silicon powder, thereby reducing the viscosity and thixotropy of the material and improving the dispersibility of the small-particle silicon powder in the large-particle silicon dioxide; preferably, the particle size D99 of the silicon dioxide is 28μm.

[0029] In some possible embodiments, the curing agent is an alicyclic amine curing agent, and the alicyclic amine curing agent includes 1,3-bis(aminomethyl)cyclohexane.

[0030] In some possible embodiments, the promoter is a latent promoter, and the latent promoter includes 1-ethylimidazole.

[0031] In some possible embodiments, the colorant includes carbon black.

[0032] Those skilled in the art can understand that the alicyclic amine curing agent reacts with the epoxy resin at high temperature to form a cross-linked cured product, preferably 1,3-bis(aminomethyl)cyclohexane (1,3-BAC); at the same time, a latent accelerator is added as a catalyst to increase the reaction rate of the alicyclic amine curing agent and the epoxy resin at high temperature and shorten the curing time of the resin material.

[0033] Based on a general inventive concept, the second aspect of the present invention provides a method for preparing the low-warpage and low-viscosity liquid mold sealant as described in the first aspect, the preparation method comprising: S1. Prepare a mixture by a high shear homogenizer, wherein the mixture is compounded by a second epoxy resin and silicon micropowder, and the mass ratio of the second epoxy resin to the silicon micropowder is 60%:40%; S2. Accurately weigh the raw material components, wherein the components include, by mass, 80 to 90 parts of filler, 1.5 to 4.5 parts of the first epoxy resin, 10 to 15 parts of the mixture, 1 to 3 parts of the curing agent, 0.2 to 0.5 parts of the accelerator, and 0.1 to 0.3 parts of the colorant; wherein the second epoxy resin is the same as the first epoxy resin; S3, adding the weighed first epoxy resin, the mixture, the curing agent and the coloring agent into a stirring cup, stirring evenly to obtain a first slurry; S4, dividing the weighed filler into three equal parts, adding the first equal part of the filler into the stirring cup, and stirring evenly; continuing to add the second equal part of the filler into the stirring cup, and stirring evenly; continuing to add the third equal part of the filler into the stirring cup, and stirring evenly, to obtain a second slurry; S5, transferring the second slurry to a three-roll mill for dispersion treatment to obtain a uniformly dispersed third slurry; S6, adding the accelerator to the third slurry, stirring evenly, to obtain a fourth slurry; S7, vacuum degassing the fourth slurry by a centrifugal mixer to obtain a liquid mold sealant.

[0034] The specific steps of preparing the mixture by the high shear homogenizer include: preparing a mixture of the second epoxy resin and silicon micropowder in a mass ratio of 60%:40%, quickly and evenly adding the silicon micropowder to the second epoxy resin, and setting the rotation speed of the stirring and mixing part of the high shear homogenizer to 3500r / min, so that the second epoxy resin and the silicon micropowder move at high speed in the narrow gap between the multi-layer rotor and the stator, and the solid and liquid phases are subjected to high-speed shearing of hundreds of thousands of times per minute in the operating chamber, forming strong hydraulic shear and turbulence, and the mixture is fully dispersed, homogenized, emulsified, crushed, refined, and fused under the synergistic effects of centrifugation, extrusion, collision, and crushing; then weigh each raw material component according to the preset reaction ratio, and the weighing is completed. Finally, the first epoxy resin, the mixture, the curing agent and the dye are stirred evenly to obtain a first slurry that is evenly mixed, and then the filler is divided into three equal parts and added to the first slurry in batches, and each batch of filler is stirred, and then the next batch is added after mixing evenly, until the filler is added and mixed evenly to obtain the second slurry; the second slurry is transferred to a three-roll grinder for dispersion treatment to obtain a third slurry that is evenly mixed, so that the various components of the raw materials are fully contacted; then the accelerator is added and stirred evenly so that the accelerator can be fully dispersed in the resin to obtain a fourth slurry; finally, the fourth slurry is vacuum degassed to obtain a liquid mold sealant, and after covering the wafer, it is dried and cured to obtain a well-packaged wafer.

[0035] In combination with the second aspect of the present application, the working parameters of the three-roll grinder include: the feed gap is 70-100μm, and the discharge gap is 40-60μm; the working parameters of the centrifugal mixer include: vacuum degassing time is 60-120s, rotation is 120r / min, and revolution is 1200r / min.

[0036] Based on a general inventive concept, a third aspect of the present invention provides a chip packaging method, the method comprising: obtaining a wafer body; Applying the low-warpage and low-viscosity liquid mold sealant described in the first aspect on the wafer body and curing it to obtain a packaged wafer; The packaged wafer is cut to obtain a plurality of well-packaged chips.

[0037] In a specific embodiment, an eight-inch wafer with grooves is selected, the wafer thickness is 700-750μm, the groove depth is 100-300μm, the width is 50-80μm, and the horizontal and vertical spacings between the grooves are 300 and 600μm respectively; at 25°C, the liquid molding glue is squeezed on the central end of the wafer, and evenly scraped all around by a rotary coater, and the amount of glue can be adjusted according to the thickness of the wafer to be packaged. After uniform coating, it is cured to obtain a well-packaged wafer; finally, according to usage requirements, the well-packaged wafer is cut to obtain a number of well-packaged chips to meet the usage scenario.

[0038] It should be noted that the liquid molding glue used to encapsulate wafers should meet the following requirements: the viscosity of the glue is less than 100 Pa·s, the thixotropic value of the glue is between 0.8-1.1, and the preferred viscosity is between 20-50 Pa.s. It can be evenly coated and printed at room temperature, and the surface is flat and free of foreign matter after printing, and there are no holes under a magnifying glass; the glue can completely fill the tiny gaps between wafers at room temperature to avoid the overflow of part of the air that was not filled during the printing process after curing, causing internal voids; the glue is applied to the surface of the wafer, and after curing, the wafer is polished and thinned until the surface is exposed, and the surface layer is free of impurities and voids under a microscope; the volume shrinkage caused by the curing process of the glue and the thermal expansion coefficients between the substrate and the chip / wafer are adapted to avoid the wafer being too warped after encapsulation to be able to proceed with subsequent cutting processes.

[0039] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0040] The components of the liquid mold sealant in Comparative Examples 1-6 and Examples 1-3 are shown in Table 1 according to mass fractions: Table 1 Raw material components by weight The liquid mold sealants provided in Examples 1-3 and Comparative Examples 1-6 were subjected to viscosity, thixotropy, warpage tests, and whether the liquid film sealants had voids and thermomechanical analysis tests. The specific test process is as follows: 1. Viscosity test method: adjust the circulating condensed water of the viscometer to 25°C, place the glue in the sleeve of the viscometer, install it to the detection position of the viscometer, plug in the temperature measuring thermocouple, adjust the speed of the viscometer to 20rpm, and read the viscosity value after 4 minutes.

[0041] 2. Thixotropy (TI) test method: Same as viscosity test method, read the viscosity value at 5rpm and divide it by the viscosity value at 50rpm, record it as TI value.

[0042] 3. Warpage test method: Take a clean silicon wafer (eight inches, 750μm thickness, 100-300μm groove depth, 50-80μm width, 300 and 600μm horizontal and vertical spacing respectively), place it in an aluminum alloy mold with a depth of 850μm and a diameter of 200mm, calculate the amount of glue required for printing a 200μm thick glue layer according to the density of the glue and the area of ​​the round glass slide, squeeze the corresponding amount of glue in the middle of the silicon wafer, use a ruler to apply it evenly from the middle to the surroundings, and obtain a warpage sample with a 200μm glue layer evenly coated on a 750μm thick silicon wafer. Put it in an oven, raise the room temperature to 130℃ and bake it for 1 hour. After it cools down naturally, take it out and use a ruler to test the warpage.

[0043] 4. Test method for voids: magnify the low warpage silicon wafer tested above under a microscope to see if there are voids and foreign matter on the surface; use an air grinder to grind the surface until the surface of the chip is exposed, and then place it under a microscope again to see if there are voids.

[0044] 5. Thermomechanical analyzer test: evenly drop the degassed glue into a polytetrafluoroethylene mold (10cm×1cm×2mm), solidify and cool at 130℃ for 1h, and then take it out; cut a sample with a length and width of about 1cm, grind it with sandpaper to make it uniform in thickness, and then place it on the test bench of the thermomechanical analyzer (TMA), measure it according to a certain heating program, and read the thermal expansion coefficient of the low temperature section (CTE1, ppm / ℃), the thermal expansion coefficient of the high temperature section (CTE2, ppm / ℃) and the TMA glass transition temperature (Tg, ℃).

[0045] The test results are shown in Table 2 below: Table 2 Test results From the above table, we can see that: (1) In Comparative Example 3, only large-particle silicon dioxide is used as the filling material, and the prepared glue is used to encapsulate the wafer. Under a microscope, the wafer has no holes before polishing, but has holes after polishing, indicating that a single filling material is not good for encapsulating the wafer and will affect the subsequent processing steps of the wafer; while Comparative Examples 1-2 and Comparative Examples 4-5 use small-particle silicon powder and large-particle silicon dioxide as filling materials, but at the same time, the viscosity and thixotropy of the glue are increased, affecting the encapsulation of the wafer; (2) From the data of Comparative Examples 4 and 6, it can be seen that the use of the homemade mixture (silicon powder and epoxy resin) of the present application can significantly reduce the viscosity, thixotropy and warping of the glue, indicating that the homemade mixture of the present application has excellent compatibility with large particles of silicon dioxide, can fill the gaps between silicon dioxide, and has a better wetting effect; (3) The adhesive prepared by the formula of Examples 1-3 has a lower viscosity and thixotropic coefficient, and when the wafer is packaged, it is observed under a microscope that there are no holes before and after polishing, and the film surface is flat, which is conducive to being used in small electronic devices; (4) Figure 2 This is a photo of the polished wafer in Example 5 viewed under a microscope, showing holes on the wafer surface; Figure 3 This is a picture of the polished wafer in Example 1 viewed under a microscope, with no holes on the wafer surface.

[0046] In summary, the present application first subject small-particle silicon micropowder and epoxy resin to high-speed shearing and full fusion into a mixture, and then fully mixes them with large-particle silicon dioxide, which can improve the dispersibility of small-particle silicon micropowder and large-particle silicon dioxide, so that the two particle sizes of filling materials can be evenly dispersed in the epoxy resin, thereby combining with the corresponding curing agent and accelerator to carry out cross-linking and curing reaction at a certain temperature to complete the packaging of the wafer, and the surface of the wafer after packaging is smooth, and there are no holes when observed under a microscope before and after polishing, which is convenient for subsequent cutting and other processes of the wafer.

[0047] 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 series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0048] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other 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.

[0049] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A low-warpage and low-viscosity liquid mold sealant, characterized in that: The liquid mold sealant includes the following components in parts by mass: 80 to 90 parts of filler, 1.5 to 4.5 parts of first epoxy resin, 10 to 15 parts of mixture, 1 to 3 parts of curing agent, 0.2 to 0.5 parts of accelerator, and 0.1 to 0.3 parts of colorant; wherein the mixture is compounded by a second epoxy resin and silicon micropowder, the mass ratio of the second epoxy resin to the silicon micropowder is 60%:40%, and the second epoxy resin is the same as the first epoxy resin.

2. The low-warpage and low-viscosity liquid mold sealant according to claim 1, characterized in that: The first epoxy resin and the second epoxy resin are both low-viscosity epoxy resins, and the viscosity of the low-viscosity epoxy resin is less than 1.5 Pa·s.

3. The low-warpage and low-viscosity liquid mold sealant according to claim 2, characterized in that: The particle size D100 of the silicon micropowder is 40-60 nm.

4. The low-warpage and low-viscosity liquid mold sealant according to claim 1, characterized in that: The filler includes silicon dioxide, and the particle size D99 of the silicon dioxide is 25 to 30 μm.

5. The low-warpage and low-viscosity liquid mold sealant according to claim 1, characterized in that: The curing agent is an alicyclic amine curing agent, and the alicyclic amine curing agent includes 1,3-bis(aminomethyl)cyclohexane.

6. The low-warpage and low-viscosity liquid mold sealant according to claim 1, characterized in that: The accelerator is a latent accelerator, and the latent accelerator includes 1-ethylimidazole.

7. The low-warpage and low-viscosity liquid mold sealant according to claim 1, characterized in that: The colorant includes carbon black.

8. A method for preparing a low-warpage and low-viscosity liquid mold sealant according to any one of claims 1 to 7, characterized in that: The preparation method comprises: A mixture is prepared by a high shear homogenizer, wherein the mixture is compounded by a second epoxy resin and silicon micropowder, and the mass ratio of the second epoxy resin to the silicon micropowder is 60%:40%; Accurately weigh the raw material components, wherein the components include, by mass, 80 to 90 parts of filler, 1.5 to 4.5 parts of the first epoxy resin, 10 to 15 parts of the mixture, 1 to 3 parts of the curing agent, 0.2 to 0.5 parts of the accelerator, and 0.1 to 0.3 parts of the dye; wherein the second epoxy resin is the same as the first epoxy resin; Add the weighed first epoxy resin, the mixture, the curing agent and the dye into a stirring cup, and stir evenly to obtain a first slurry; Divide the weighed filler into three equal parts, add the first equal part of the filler into the stirring cup, and stir evenly; continue to add the second equal part of the filler into the stirring cup, and stir evenly; continue to add the third equal part of the filler into the stirring cup, and stir evenly to obtain a second slurry; Transferring the second slurry to a three-roll mill for dispersion treatment to obtain a uniformly dispersed third slurry; Adding the accelerator to the third slurry and stirring evenly to obtain a fourth slurry; The fourth slurry is vacuum degassed by a centrifugal mixer to obtain a liquid mold sealant.

9. The method for preparing the low-warpage and low-viscosity liquid molding compound according to claim 8, characterized in that: The working parameters of the three-roll mill include: the feeding gap is 70-100 μm, and the discharging gap is 40-60 μm; The working parameters of the centrifugal mixer include: vacuum degassing time of 60 to 120 seconds, rotation of 120 r / min, and revolution of 1200 r / min.

10. A chip packaging method, characterized in that: The method comprises: Obtaining a wafer body; Applying the low-warpage and low-viscosity liquid mold sealant according to any one of claims 1 to 7 on the wafer body and curing it to obtain a packaged wafer; The packaged wafer is cut to obtain a plurality of well-packaged chips.

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