Low warpage low viscosity liquid mold encapsulation adhesive, preparation method thereof and chip packaging method

Abstract

The application provides a low-warp and low-viscosity liquid mold sealant, a preparation method thereof and a chip packaging method. The liquid mold sealant comprises the following components in mass fractions: 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 dyeing agent. The mixture is prepared by compounding a second epoxy resin and silicon powder, the mass ratio of the second epoxy resin to the silicon powder is 60:40, and the second epoxy resin is the same as the first epoxy resin. The second epoxy resin and the silicon powder are compounded at a mass ratio of 60:40 to prepare the mixture, so that the silicon powder can be fully dispersed in the second epoxy resin, the compatibility of the silicon powder with the filler and the first epoxy resin is improved, the gap between the filler and the silicon powder is reduced, and then the viscosity, thixotropy and warp of the glue solution are reduced.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor chip packaging technology, and specifically relates to a low-warpage, low-viscosity liquid molding compound and its preparation method, as well as a chip packaging method. Background Technology

[0002] From smartphones to intelligent driving in cars, from 5G networks to the AI ​​era, with the increasing development of intelligent production and lifestyles, semiconductor applications are almost ubiquitous. The bonding technology of semiconductor packaging plays an important role in making semiconductors smaller, more functional, more reliable, and cheaper.

[0003] In traditional wafer packaging, the finished wafer is diced into individual chips and then bonded together. Wafer-level packaging, on the other hand, first encapsulates the wafer, with a protective layer bonded to the top or bottom, then connects the circuitry, and finally dices the wafer into individual chips, resulting in packaged chips whose size is close to or even equal to the size of the bare die on the wafer. However, due to the difference in thermal expansion coefficients between the packaging material and the substrate or chip during the curing process, warping can occur after the packaging material cures, affecting processes such as wafer dicing.

[0004] Therefore, how to provide a low-warpage, low-viscosity liquid molding compound by preparing a mixture of silica powder and epoxy resin to improve the compatibility between the filler and the epoxy resin, thereby reducing the warpage of the material, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a low-warpage, low-viscosity liquid molding compound and its preparation method, as well as a chip packaging method, so as to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the first aspect of the present invention provides a low-warpage, low-viscosity liquid molding sealant, comprising, by weight parts: 80-90 parts of filler, 1.5-4.5 parts of a first epoxy resin, 10-15 parts of a mixture, 1-3 parts of curing agent, 0.2-0.5 parts of accelerator, and 0.1-0.3 parts of colorant; wherein the mixture is composed of a second epoxy resin and silica powder, the mass ratio of the second epoxy resin to the silica powder being 60%:40%, and the second epoxy resin being 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, wherein 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 micropowder is 40-60 nm.

[0009] In the first aspect, the filler comprises silica, wherein the silica has a particle size D99 of 25–30 μm.

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

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

[0012] In the first aspect, the dyeing agent includes carbon black.

[0013] A second aspect of the present invention provides a method for preparing a low-warpage, low-viscosity liquid molding sealant as described in the first aspect. The method includes: preparing a mixture using a high-shear homogenizer, the mixture being a compound of a second epoxy resin and silica powder, wherein the mass ratio of the second epoxy resin to the silica powder is 60%:40%; accurately weighing each component of the raw materials, wherein each component, by mass parts, specifically includes: 80-90 parts of filler, 1.5-4.5 parts of the first epoxy resin, 10-15 parts of the mixture, 1-3 parts of curing agent, 0.2-0.5 parts of accelerator, and 0.1-0.3 parts of colorant; wherein the second epoxy resin and the first epoxy resin are the same; and weighing the first... Epoxy resin, the mixture, the curing agent, and the dyeing agent are added to a mixing cup and stirred until homogeneous to obtain a first slurry. The weighed filler is divided into three equal parts, and the first equal part of the filler is added to the mixing cup and stirred until homogeneous. The second equal part of the filler is added to the mixing cup and stirred until homogeneous. The third equal part of the filler is added to the mixing cup and stirred until homogeneous to obtain a second slurry. The second slurry is transferred to a three-roll mill for dispersion treatment to obtain a homogeneous third slurry. The accelerator is added to the third slurry and stirred until homogeneous to obtain a fourth slurry. The fourth slurry is vacuum degassed using a centrifugal mixer to obtain a liquid molding sealant.

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

[0015] A third aspect of the present invention provides a chip packaging method, the method comprising: obtaining a wafer body; coating the wafer body with a liquid encapsulant of low warpage and low viscosity as described in the first aspect, and curing it to obtain a packaged wafer; and cutting the packaged wafer to obtain a plurality of packaged chips.

[0016] Beneficial effects:

[0017] This invention provides a low-warpage, low-viscosity liquid molding sealant, comprising the following components by weight: 80-90 parts filler, 1.5-4.5 parts first epoxy resin, 10-15 parts mixture, 1-3 parts curing agent, 0.2-0.5 parts accelerator, and 0.1-0.3 parts colorant; wherein the mixture is composed of a second epoxy resin and silica powder, with a mass ratio of 60%:40% for the second epoxy resin and the first epoxy resin being the same; First, a mixture is prepared by compounding a second epoxy resin and silicon micropowder at a mass ratio of 60%:40%. This ensures that the silicon micropowder is fully dispersed in the second epoxy resin, improving the compatibility of the silicon micropowder with the filler and the first epoxy resin, reducing the gap between the filler and the silicon micropowder, and thus reducing the viscosity, thixotropy, and warpage of the adhesive. Simultaneously, a curing agent and an accelerator are used to cure the adhesive into a film, and a dye is used to mark the film, thereby forming a liquid molding compound suitable for wafer encapsulation. This invention improves the compatibility between the raw material components and reduces the gap between the filler and the silicon micropowder by pre-preparing a compound mixture of the second epoxy resin and silicon micropowder, thereby reducing the viscosity and thixotropy of the adhesive, resulting in a better leveling effect and lower warpage after curing. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating a method for preparing a low-warpage, low-viscosity liquid molding compound provided by the present invention;

[0020] Figure 2 The image shown under a microscope is a comparative example 5 of the present invention, depicting the effect of the wafer after polishing.

[0021] Figure 3 This is a microscopic image showing the effect of the wafer after polishing in Embodiment 1 of the present invention. Detailed Implementation

[0022] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0023] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning 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 pertains. In the event of any conflict, this specification shall prevail.

[0024] 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.

[0025] This invention provides a low-warpage, low-viscosity liquid molding sealant, comprising the following components by weight: 80-90 parts filler, 1.5-4.5 parts first epoxy resin, 10-15 parts mixture, 1-3 parts curing agent, 0.2-0.5 parts accelerator, and 0.1-0.3 parts colorant; wherein the mixture is composed of a second epoxy resin and silica powder, the mass ratio of the second epoxy resin to the silica powder being 60%:40%, and the second epoxy resin being the same as the first epoxy resin.

[0026] Specifically, the present invention provides a low-warpage, low-viscosity liquid molding compound, comprising the following components by weight: 80-90 parts filler, 1.5-4.5 parts first epoxy resin, 10-15 parts mixture, 1-3 parts curing agent, 0.2-0.5 parts accelerator, and 0.1-0.3 parts colorant; wherein the mixture is composed of a second epoxy resin and silica powder, with a mass ratio of 60%:40% for the second epoxy resin and the first epoxy resin... The same principle applies; firstly, a mixture of second epoxy resin and silicon micropowder is prepared at a mass ratio of 60%:40%, allowing the silicon micropowder to be fully dispersed in the second epoxy resin. This improves the compatibility of the silicon micropowder with the filler and the first epoxy resin, reduces the gap between the filler and the silicon micropowder, and thus reduces the viscosity, thixotropy, and warpage of the adhesive. Simultaneously, a curing agent and an accelerator are used to cure the adhesive into a film, and a dye is used to mark the film, thereby forming a liquid molding compound that can encapsulate wafers. This invention improves the compatibility between the components of the raw materials by pre-preparing a compound mixture of second epoxy resin and silicon micropowder, reducing the gap between the filler and the silicon micropowder, thereby reducing the viscosity and thixotropy of the adhesive, resulting in a better leveling effect and lower warpage after curing.

[0027] In some possible embodiments, both the first epoxy resin and the second epoxy resin are low-viscosity epoxy resins, wherein the viscosity of the low-viscosity epoxy resin is less than 1.5 Pa·s.

[0028] This is because selecting low-viscosity epoxy resins with a viscosity of less than 1.5 Pa·s for both the first and second epoxy resins can improve the dispersibility of fillers in the epoxy resin. Mixing silica powder with the second epoxy resin can also reduce the viscosity of the material. The epoxy resin can be any one of phenolic epoxy resin, amino tetrafunctional epoxy resin, aminophenol trifunctional epoxy resin, bisphenol S epoxy resin, bisphenol A type epoxy resin, bisphenol F epoxy resin, silicone-containing epoxy resin, or hexafunctional epoxy resin. Preferably, the epoxy resin is bisphenol F epoxy resin, with the model number ZLF-160U.

[0029] In some possible embodiments, the particle size D100 of the silicon micropowder is 40–60 nm.

[0030] Those skilled in the art will understand that the particle size D100 of the silicon micropowder is 40-60 nm. First, the silicon micropowder is mixed with epoxy resin, and then the mixture is mixed with large-particle filler. This can improve the dispersibility of the small-particle silicon micropowder in the large-particle filler, while the epoxy resin can also be fully filled in the silicon micropowder. Preferably, the particle size D100 of the silicon micropowder is 50 nm.

[0031] In some possible embodiments, the filler comprises silica with a particle size D99 of 25–30 μm.

[0032] This is because, while using only one type of silica as a filler material can reduce the coefficient of thermal expansion and warpage of the resin material, large silica particles have poor dispersibility and significant warpage, making them unsuitable for encapsulating large wafers. Therefore, two filler materials with different particle sizes are used to improve dispersibility. First, small-particle-size silica powder is mixed with epoxy resin at high speed to prepare a uniformly dispersed and fully fused mixture. Then, the mixture is mixed with large silica particles, allowing the epoxy resin to fully fill the gaps between the large silica particles and the small silica particles, thereby reducing the viscosity and thixotropy of the material and improving the dispersibility of the small silica particles in the large silica particles. Preferably, the silica particle size D99 is 28 μm.

[0033] In some possible embodiments, the curing agent is an alicyclic amine curing agent, which includes 1,3-di(aminomethyl)cyclohexane.

[0034] In some possible embodiments, the promoter is a latent promoter, which includes 1-ethylimidazole.

[0035] In some possible embodiments, the dyeing agent includes carbon black.

[0036] Those skilled in the art will understand that alicyclic amine curing agents react with epoxy resins at high temperatures to generate cross-linked cured products, preferably 1,3-di(aminomethyl)cyclohexane (1,3-BAC); at the same time, a latent accelerator is added as a catalyst to increase the reaction rate of alicyclic amine curing agents and epoxy resins at high temperatures and shorten the curing time of the resin material.

[0037] Based on a general inventive concept, a second aspect of the present invention provides a method for preparing a low-warpage, low-viscosity liquid molding compound as described in the first aspect, the method comprising:

[0038] S1. A mixture is prepared by a high-shear homogenizer, the mixture being composed of a second epoxy resin and silicon micro powder, wherein the mass ratio of the second epoxy resin to the silicon micro powder is 60%:40%.

[0039] S2. Accurately weigh each component of the raw material, wherein each component specifically includes, by mass parts: 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 second epoxy resin is the same as the first epoxy resin;

[0040] S3. The weighed first epoxy resin, the mixture, the curing agent and the dyeing agent are added to a mixing cup and stirred evenly to obtain the first slurry;

[0041] S4. Divide the weighed filler into three equal parts, add the first equal part of the filler to the mixing cup, and stir evenly; continue to add the second equal part of the filler to the mixing cup, and stir evenly; continue to add the third equal part of the filler to the mixing cup, and stir evenly to obtain the second slurry;

[0042] S5. The second slurry is transferred to a three-roll mill for dispersion treatment to obtain a uniformly dispersed third slurry;

[0043] S6. Add the accelerator to the third slurry, stir evenly, and obtain the fourth slurry;

[0044] S7. The fourth slurry is vacuum degassed using a centrifugal mixer to obtain liquid molding compound.

[0045] The specific steps for preparing the mixture using a high-shear homogenizer include: preparing a mixture of second epoxy resin and silicon powder at a mass ratio of 60%:40%; rapidly and uniformly adding the silicon powder to the second epoxy resin; and setting the rotation speed of the mixing section of the high-shear homogenizer to 3500 r / min, so that the second epoxy resin and silicon powder move at high speed in the narrow gap between the multi-layer rotor and stator. The solid and liquid phases are subjected to hundreds of thousands of high-speed shearing cycles per minute in the operating chamber, forming strong hydraulic shearing and turbulence. Under the synergistic effects of centrifugation, extrusion, collision, and pulverization, a fully dispersed, homogenized, emulsified, broken, refined, and fused mixture is obtained; then, each raw material component is weighed according to the preset reaction ratio, and the weighing is completed. First, the first epoxy resin, mixture, curing agent, and dye are stirred evenly to obtain a uniformly mixed first slurry. Then, the filler is divided into three equal parts and added to the first slurry in batches. Each batch of filler is stirred and mixed evenly before adding the next batch, until all filler is added and the mixture is uniformly mixed to obtain a second slurry. The second slurry is transferred to a three-roll mill for dispersion treatment to obtain a uniformly mixed third slurry, ensuring that all components of the raw materials are in full contact. Next, an accelerator is added and stirred evenly to ensure that the accelerator is fully dispersed in the resin, resulting in a fourth slurry. Finally, the fourth slurry is vacuum degassed to obtain a liquid molding sealant, which is then used to cover the wafer and dried and cured to obtain a properly packaged wafer.

[0046] In conjunction with the second aspect of this application, the operating parameters of the three-roll mill include: a feed gap of 70-100 μm and a discharge gap of 40-60 μm; the operating parameters of the centrifugal mixer include: a vacuum degassing time of 60-120 s, a rotation of 120 r / min, and a revolution of 1200 r / min.

[0047] 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;

[0048] The low-warpage, low-viscosity liquid molding compound described in the first aspect is coated onto the wafer body and cured to obtain an encapsulated wafer.

[0049] The packaged wafer is cut to obtain several well-packaged chips.

[0050] In a specific embodiment, an 8-inch wafer with trenches is selected, with a wafer thickness of 700-750μm, a trench depth of 100-300μm, a width of 50-80μm, and a horizontal and vertical spacing of 300μm and 600μm, respectively. At 25°C, the liquid molding encapsulant is squeezed onto the center of the wafer and evenly coated outwards using a rotary coater. The amount of encapsulant can be adjusted according to the required encapsulation thickness of the wafer. After uniform coating, the wafer is cured to obtain a fully encapsulated wafer. Finally, according to the usage requirements, the fully encapsulated wafer is cut to obtain several fully encapsulated chips to meet the usage scenario.

[0051] It should be further noted that the liquid molding compound used for wafer encapsulation should meet the following requirements: the viscosity of the compound should be less than 100 Pa·s, the thixotropic value of the compound should be between 0.8 and 1.1, preferably between 20 and 50 Pa·s, it should be able to be uniformly coated and printed at room temperature, and the printed surface should be smooth and free of foreign matter, and there should be no pores when viewed under a magnifying glass; at room temperature, the compound should be able to completely fill the tiny gaps between the wafers, avoiding the leakage of air from unfilled parts during the printing process after curing, which could cause internal voids; after the compound is coated on the wafer surface and cured, the wafer should be polished and thinned until the surface layer is exposed, and the surface layer should be free of impurities and voids when viewed under a microscope; the volume shrinkage caused by the compound curing process and the coefficient of thermal expansion between the substrate and the chip / wafer should be compatible to avoid the wafer warping too much after encapsulation, which would prevent subsequent cutting processes.

[0052] 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.

[0053] The components of the liquid molding compound in Comparative Examples 1-6 and Examples 1-3, according to their mass parts, are shown in Table 1 below:

[0054] Table 1. Mass parts of raw material components

[0055]

[0056] Viscosity, thixotropy, warpage tests, and tests for voids and thermomechanical properties were performed on the liquid molding sealants provided in Examples 1-3 and Comparative Examples 1-6. The specific test procedures are as follows:

[0057] 1. Viscosity test method: Adjust the circulating cooling water of the viscometer to 25℃, place the adhesive in the sleeve of the viscometer, install it in the detection position of the viscometer, insert the temperature measuring thermocouple, adjust the speed of the viscometer to 20 rpm, and read the viscosity value after 4 minutes.

[0058] 2. Thixotropic (TI) test method: Similar to the viscosity test method, read the viscosity value at 5 rpm and divide it by the viscosity value at 50 rpm, and record it as the TI value.

[0059] 3. Warpage Test Method: Take a clean silicon wafer (8-inch, 750μm thick, trench depth 100-300μm, width 50-80μm, horizontal and vertical spacing 300 and 600μm respectively), place it in an aluminum alloy mold with a depth of 850μm and a diameter of 200mm, calculate the amount of adhesive required to print a 200μm thick adhesive layer based on the density of the adhesive and the area of ​​the circular glass slide, squeeze the corresponding amount of adhesive into the center of the silicon wafer, and use a ruler to spread it evenly from the center to the periphery to obtain a warpage sample with a 200μm adhesive layer evenly coated on a 750μm thick silicon wafer, place it in an oven, bake at room temperature to 130℃ for 1 hour, and after it cools down naturally, take it out and use a ruler to test the warpage.

[0060] 4. Test method for voids: Place the low warp silicon wafer tested above under a microscope to observe whether there are voids and foreign objects on the surface; use an air grinder to polish the surface until the chip surface is exposed, and then place it under a microscope again to observe whether there are voids.

[0061] 5. Thermomechanical analysis test: The degassed adhesive was evenly dripped into a polytetrafluoroethylene mold (10cm×1cm×2mm), cured at 130℃ for 1 hour and then removed. A sample block with a length and width of about 1cm was cut and sanded to make the thickness uniform. Then it was placed on the test stage of the thermomechanical analyzer (TMA) and measured according to a certain temperature rise program. The coefficient of thermal expansion in the low temperature range (CTE1, ppm / ℃), the coefficient of thermal expansion in the high temperature range (CTE2, ppm / ℃) and the glass transition temperature of TMA (Tg, ℃) were read.

[0062] The test results are shown in Table 2 below:

[0063] Table 2 Test Results

[0064]

[0065] As can be seen from the table above:

[0066] (1) In Comparative Example 3, only large-particle silicon dioxide was used as the filler material. The prepared adhesive was used to encapsulate the wafer. Under a microscope, the wafer was pore-free before polishing, but pores appeared after polishing. This indicates that a single filler material is not good for wafer encapsulation and will affect the subsequent processing steps of the wafer. Although Comparative Examples 1-2 and 4-5 used small-particle silicon micro powder and large-particle silicon dioxide as filler materials, they also increased the viscosity and thixotropy of the adhesive, which affected the wafer encapsulation.

[0067] (2) As can be seen from the data of Comparative Example 4 and Comparative Example 6, the mixture (silica powder and epoxy resin) prepared in this application can significantly reduce the viscosity, thixotropy and warpage of the adhesive, indicating that the mixture prepared in this application has excellent compatibility with large particles of silica and can fill the gaps between silica particles, resulting in better wetting effect.

[0068] (3) The adhesive prepared by the formulation of Examples 1-3 has a low viscosity and thixotropic coefficient. When the wafer is packaged, under a microscope, there are no pores before and after polishing, and the film surface is flat, which is beneficial for its application in small electronic devices.

[0069] (4) Figure 2 This is a microscopic image of the wafer in Comparative Example 5 after polishing, showing holes on the wafer surface. Figure 3 This is a microscopic image of the wafer after polishing in Example 1, showing that the wafer surface is free of pores.

[0070] In summary, this application first performs high-speed shearing and thorough fusion of small-diameter silicon micropowder with epoxy resin to form a mixture, and then thoroughly mixes it with large-particle silica. This improves the dispersibility of the small-diameter silicon micropowder and the large-particle silica, allowing the two particle sizes of filler materials to be uniformly dispersed in the epoxy resin. This, combined with the corresponding curing agent and accelerator, allows for cross-linking and curing at a certain temperature, completing the wafer encapsulation. The encapsulated wafer has a smooth surface, and microscopic observation before and after polishing shows no pores, facilitating subsequent wafer cutting and other processing steps.

[0071] 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.

[0072] 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.

[0073] 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. A low-warpage, low-viscosity liquid molding compound, characterized in that, The liquid molding sealant comprises the following components by weight: 80-90 parts filler, 1.5-4.5 parts first epoxy resin, 10-15 parts mixture, 1-3 parts curing agent, 0.2-0.5 parts accelerator, and 0.1-0.3 parts coloring agent; wherein the mixture is composed of a 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; 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; The particle size D100 of the silicon micropowder is 40-60 nm; The filler includes silica, and the silica has a particle size D99 of 25-30 μm.

2. The low-warpage, low-viscosity liquid molding compound according to claim 1, characterized in that, The curing agent is an alicyclic amine curing agent, which includes 1,3-bis(aminomethyl)cyclohexane.

3. The low-warpage, low-viscosity liquid molding compound according to claim 1, characterized in that, The promoter is a latent promoter, and the latent promoter includes 1-ethylimidazole.

4. The low-warpage, low-viscosity liquid molding compound according to claim 1, characterized in that, The dyeing agent includes carbon black.

5. A method for preparing a low-warpage, low-viscosity liquid molding compound as described in any one of claims 1-4, characterized in that, The preparation method includes: A mixture was prepared by a high-shear homogenizer. The mixture was composed of a second epoxy resin and silica powder, wherein the mass ratio of the second epoxy resin to the silica powder was 60%:40%. Accurately weigh each component of the raw material, which specifically includes, by mass parts: 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 second epoxy resin is the same as the first epoxy resin; The weighed first epoxy resin, the mixture, the curing agent and the dyeing agent are added to a mixing cup and stirred evenly to obtain the first slurry; The weighed filler is divided into three equal parts. The first equal part of the filler is added to the mixing cup and stirred evenly. The second equal part of the filler is added to the mixing cup and stirred evenly. The third equal part of the filler is added to the mixing cup and stirred evenly to obtain the second slurry. The second slurry is transferred to a three-roll mill for dispersion treatment to obtain a uniformly dispersed third slurry; The accelerator is added to the third slurry, and after stirring evenly, a fourth slurry is obtained; The fourth slurry was vacuum degassed using a centrifugal mixer to obtain a liquid molding sealant.

6. The method for preparing the low-warpage, low-viscosity liquid molding compound according to claim 5, characterized in that, The operating parameters of the three-roll mill include: a feed gap of 70–100 μm and a discharge gap of 40–60 μm; The operating parameters of the centrifugal mixer include: vacuum degassing time of 60-120s, rotation of 120r / min, and revolution of 1200r / min.

7. A chip packaging method, characterized in that, The method includes: Obtain the wafer body; The low-warpage, low-viscosity liquid molding compound of any one of claims 1-4 is coated onto the wafer body and cured to obtain an encapsulated wafer. The packaged wafer is cut to obtain several well-packaged chips.

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