Low warpage and easy to grind printed state film encapsulation, preparation method and packaging structure

Abstract

The application discloses a low-warp and easy-to-grind printed film encapsulation adhesive, a preparation method and an encapsulation structure, relates to the technical field of semiconductor chip encapsulation, and the printed film encapsulation adhesive comprises the following components in percentage by mass: 81-88% of a filler, 4-8% of an alicyclic epoxy resin, 1-2% of an MQ silicone resin, 1-2% of a polydimethylsiloxane, 5-9% of an acid anhydride curing agent, 0.3-0.5% of a surfactant, 0.1-0.2% of an accelerator, 0.2-0.4% of a leveling agent and 0.1-0.2% of carbon black; wherein the filler is composed of first and second spherical silicas, the particle size of the first spherical silica is 3-25 mu m, and the particle size of the second spherical silica is 1-5 mu m. By selecting fillers with different particle sizes and introducing the MQ silicone resin and the polydimethylsiloxane into the epoxy system, the application reduces the curing shrinkage of the film encapsulation adhesive and improves the dispersibility, thereby effectively reducing the warp and water absorption of the film encapsulation adhesive after curing, improving the grinding efficiency and the chip encapsulation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor chip packaging technology, and specifically relates to a low-warpage and easily grindable printed film encapsulant, its preparation method, and its packaging structure. Background Technology

[0002] In modern semiconductor packaging processes, the performance of encapsulants directly impacts packaging reliability and subsequent processing quality. With the continuous shrinkage of package sizes and increasing integration density, the requirements for encapsulants are becoming increasingly stringent. Currently, due to the trend towards thinner package structures, stress control during the curing process of encapsulants has become particularly important. Traditional epoxy resin-based materials often generate significant shrinkage stress during curing, leading to warping deformation of the package structure. This warping not only affects the coplanarity between the chip and the substrate, resulting in poor soldering and decreased reliability, but also causes processing accuracy issues in subsequent cutting and grinding processes. Simultaneously, as package thickness decreases, higher demands are placed on the machinability of encapsulants. In the back-end processes of wafer-level packaging, precise grinding of the encapsulation layer is typically required to achieve the target thickness. Traditional encapsulants often suffer from low grinding efficiency and high surface roughness, which not only affects production efficiency but may also damage the chip. Furthermore, the heat accumulation generated during grinding further exacerbates the thermal stress of the material, potentially triggering new warping problems.

[0003] Therefore, how to provide a low-warpage, easy-to-grind printable encapsulant by adding MQ silicone resin and polydimethylsiloxane to the epoxy resin system to optimize the resin system, thereby reducing the curing shrinkage rate of the encapsulant and improving the dimensional stability and encapsulation reliability of the encapsulant after curing, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a low-warpage and easily grindable printed film encapsulant, its preparation method, and its packaging structure, so as to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, a first aspect of the present invention provides a low-warpage and easily grindable printable film sealant, wherein the printable film sealant comprises, by weight percentage: 81%-88% filler, 4%-8% alicyclic epoxy resin, 1%-2% MQ silicone resin, 1%-2% polydimethylsiloxane, 5%-9% anhydride curing agent, 0.3%-0.5% surfactant, 0.1%-0.2% accelerator, 0.2%-0.4% leveling agent, and 0.1%-0.2% carbon black; wherein the filler is composed of a first spherical silica and a second spherical silica, wherein the particle size of the first spherical silica is 3-25 μm, and the particle size of the second spherical silica is 1-5 μm.

[0006] In the first aspect, the first spherical silica has a mass percentage of 80%-85%, and the second spherical silica has a mass percentage of 1%-2%.

[0007] In the first aspect, the MQ ratio of the MQ silicone resin is 0.70-0.75.

[0008] In the first aspect, the viscosity of the polydimethylsiloxane is 10-50 cs.

[0009] In the first aspect, the surfactant has a mass percentage of 0.4%, the accelerator has a mass percentage of 0.1%, the leveling agent has a mass percentage of 0.3%, and the carbon black has a mass percentage of 0.2%.

[0010] In the first aspect, the surfactant includes polyether surfactants.

[0011] In the first aspect, the leveling agent includes an organosilicon leveling agent or a polyether-modified polydimethylsiloxane.

[0012] The second aspect of this invention provides a method for preparing a low-warpage and easily grindable printable film sealant. The method includes: accurately weighing each component of the raw materials in the low-warpage and easily grindable printable film sealant described in the first aspect; mixing the weighed MQ silicone resin and polydimethylsiloxane uniformly at a mixing temperature of 80-100℃ for 20-30 minutes to obtain a premix; adding weighed filler, alicyclic epoxy resin, an anhydride curing agent, surfactant, accelerator, leveling agent, and carbon black to the premix, and mixing uniformly to obtain a mixture; dispersing the mixture using a three-roll mill to obtain a uniformly dispersed slurry; and vacuum degassing the slurry to obtain a low-warpage and easily grindable printable film sealant.

[0013] A third aspect of the present invention provides a packaging structure, including a chip and a molding compound bonded to the six sides of the chip. The molding compound is formed by curing the low-warpage and easily grindable printed film encapsulant described in the first aspect, with a curing temperature of 180°C and a curing time of 2 hours.

[0014] In the third aspect, the warpage of the printed film sealant after curing is less than 2.5 mm, and the water absorption rate is less than 0.25%.

[0015] Beneficial effects:

[0016] The present invention provides a low-warpage and easily grindable printable film sealant, comprising the following components by weight percentage: 81%-88% filler, 4%-8% alicyclic epoxy resin, 1%-2% MQ silicone resin, 1%-2% polydimethylsiloxane, 5%-9% anhydride curing agent, 0.3%-0.5% surfactant, 0.1%-0.2% accelerator, 0.2%-0.4% leveling agent, and 0.1%-0.2% carbon black; wherein the filler is composed of a first spherical silica and a second spherical silica, the first spherical silica having a particle size of 3-25 μm and the second spherical silica having a particle size of 1-5 μm; By using fillers of different particle sizes in combination, the voids in the cured encapsulant are reduced, shrinkage stress is lowered, and warpage is thus reduced. The flexible siloxane chains in MQ silicone resin disperse shrinkage stress during curing or cooling, thereby reducing warpage. This also improves the dispersibility of the filler in the resin system, reducing deformation caused by localized shrinkage differences. Polydimethylsiloxane migrates to the surface of the encapsulant during printing, forming a hydrophobic layer, which reduces the water absorption rate of the encapsulant. Simultaneously, the addition of polydimethylsiloxane reduces the crosslinking degree of the epoxy curing reaction, improving chain flowability and grinding effect, thus reducing the consumption of grinding wheels in the grinding machine. This invention, by selecting fillers of different particle sizes and introducing MQ silicone resin and polydimethylsiloxane into the epoxy system, reduces the curing shrinkage rate of the encapsulant and improves its dispersibility, thereby effectively reducing the warpage and water absorption rate of the cured encapsulant, improving grinding efficiency and chip packaging efficiency. Detailed Implementation

[0017] 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.

[0018] 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.

[0019] 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.

[0020] This invention provides a low-warpage and easily grindable printable film sealant, which comprises the following components by weight percentage: 81%-88% filler, 4%-8% alicyclic epoxy resin, 1%-2% MQ silicone resin, 1%-2% polydimethylsiloxane, 5%-9% anhydride curing agent, 0.3%-0.5% surfactant, 0.1%-0.2% accelerator, 0.2%-0.4% leveling agent, and 0.1%-0.2% carbon black; wherein the filler is composed of a first spherical silica and a second spherical silica, the first spherical silica having a particle size of 3-25 μm and the second spherical silica having a particle size of 1-5 μm.

[0021] Specifically, the present invention provides a low-warpage and easily grindable printable film encapsulant, comprising the following components by weight percentage: 81%-88% filler, 4%-8% alicyclic epoxy resin, 1%-2% MQ silicone resin, 1%-2% polydimethylsiloxane, 5%-9% anhydride curing agent, 0.3%-0.5% surfactant, 0.1%-0.2% accelerator, 0.2%-0.4% leveling agent, and 0.1%-0.2% carbon black; wherein the filler is composed of a first spherical silica and a second spherical silica, the first spherical silica having a particle size of 3-25 μm, and the second spherical silica having a particle size of 1-5 μm. μm; By using fillers of different particle sizes in combination, the voids in the cured encapsulant are reduced, shrinkage stress is lowered, and warpage is reduced. The flexible siloxane chains in MQ silicone resin disperse shrinkage stress during curing or cooling, thereby reducing warpage. This also improves the dispersibility of the filler in the resin system, reducing deformation caused by localized shrinkage differences. Polydimethylsiloxane migrates to the surface of the encapsulant during printing, forming a hydrophobic layer, thus reducing the water absorption rate of the encapsulant. Simultaneously, the addition of polydimethylsiloxane reduces the crosslinking degree of the epoxy curing reaction, improving chain flowability and grinding effect, thereby reducing the consumption of grinding wheels in the grinding machine. This invention, by selecting fillers of different particle sizes and introducing MQ silicone resin and polydimethylsiloxane into the epoxy system, reduces the curing shrinkage rate of the encapsulant and improves its dispersibility, thereby effectively reducing the warpage and water absorption rate of the cured encapsulant, improving grinding efficiency and chip packaging efficiency.

[0022] In some possible embodiments, the first spherical silica has a mass percentage of 80%-85%, and the second spherical silica has a mass percentage of 1%-2%.

[0023] In this application, large-particle-size spherical silica is used as the main filler to enhance the modulus of the film sealant. At the same time, a small amount of small-particle-size spherical silica is added to fill the gaps and form more interfacial bonding with epoxy resin, thereby improving the adhesion of the film sealant. By using spherical silica of different particle sizes, the voids after the film sealant is cured can be reduced, the shrinkage stress can be reduced, and thus the warpage and water absorption rate of the film sealant can be reduced.

[0024] In some possible embodiments, the MQ ratio of the MQ silicone resin is 0.70-0.75.

[0025] Specifically, the flexible siloxane chain (Si-O) of MQ silicone resin can disperse shrinkage stress during the curing or cooling process, reduce warping caused by uneven stress, and promote the uniform distribution of spherical silica in the matrix epoxy resin, reducing deformation caused by local shrinkage differences, thereby improving the adhesion and water resistance of the film sealant and reducing wafer warping.

[0026] In some possible embodiments, the viscosity of the polydimethylsiloxane is 10-50 cs.

[0027] In this application, polydimethylsiloxane is a non-polar organosilicon compound with low surface tension. When added to an epoxy system, it migrates to the surface of the encapsulant to form a hydrophobic layer, thereby reducing the surface tension of the encapsulant, improving the leveling and wetting properties of the encapsulant solution, and reducing bubble formation. Polydimethylsiloxane does not participate in the reaction but can be mixed in the system, reducing the degree of cross-linking reaction, reducing the compactness of the cured product, and enhancing the grinding effect. In addition, the Si-O-Si backbone of polydimethylsiloxane has high flexibility and low internal rotational resistance, and the molecular chain is easy to slide, reducing friction and reducing the wear of the grinding wheel in the wafer grinding machine.

[0028] In some possible embodiments, the surfactant is 0.4% by mass, the accelerator is 0.1% by mass, the leveling agent is 0.3% by mass, and the carbon black is 0.2% by mass.

[0029] In some possible embodiments, the surfactant includes polyether surfactants.

[0030] In some possible embodiments, the leveling agent includes a silicone leveling agent or a polyether-modified polydimethylsiloxane.

[0031] In this application, the crosslinking curing reaction time and the leveling performance after film sealing are controlled by adding surfactants, accelerators and leveling agents to the formulation.

[0032] Based on a general inventive concept, the second aspect of this invention provides a method for preparing a low-warpage and easily grindable printable film sealant. The method includes: accurately weighing each component of the raw materials in the low-warpage and easily grindable printable film sealant described in the first aspect; mixing the weighed MQ silicone resin and polydimethylsiloxane uniformly at a mixing temperature of 80-100℃ for 20-30 minutes to obtain a premix; adding weighed fillers, alicyclic epoxy resin, anhydride curing agents, surfactants, accelerators, leveling agents, and carbon black to the premix, mixing uniformly to obtain a mixture; dispersing the mixture using a three-roll mill to obtain a uniformly dispersed slurry; and vacuum degassing the slurry to obtain a low-warpage and easily grindable printable film sealant.

[0033] In this application, firstly, the weighed MQ silicone resin and polydimethylsiloxane are mixed at 80-100℃ for 20-30 minutes until homogeneous to obtain a premix; secondly, weighed spherical silica (3-25μm), spherical silica (1-5μm), epoxy resin, curing agent, surfactant, accelerator, leveling agent, and carbon black are added to the premix, and then mixed homogeneously using a centrifugal mixer to obtain a mixture; wherein the operating parameters of the centrifugal mixer include: mixing time of 160-300s, rotation speed of 120... The mixture is first moved at 0 r / min and then rotated at 1500 r / min. Next, it is dispersed using a three-roll mill to obtain a uniformly dispersed slurry. The operating parameters of the three-roll mill include: feed gap of 65-95 μm and discharge gap of 40-60 μm. Finally, the slurry is vacuum degassed using a centrifugal mixer. The operating parameters of the centrifugal mixer include: vacuum degassed time of 70-90 s, rotation at 1200 r / min, and revolution at 1500 r / min, resulting in a low-warpage and easily grindable printable film sealant.

[0034] Based on a general inventive concept, the third aspect of the present invention provides a packaging structure including a chip and a molding compound bonded to the six sides of the chip. The molding compound is formed by curing the low-warpage and easily grindable printed film encapsulant described in the first aspect, with a curing temperature of 180°C and a curing time of 2 hours.

[0035] In conjunction with the third aspect, the warpage of the printed film sealant after curing is less than 2.5 mm, and the water absorption rate is less than 0.25%.

[0036] The encapsulant prepared using the above formula ratio is used to encapsulate the chip on all six sides. After curing at 180°C for 2 hours, the warpage of the encapsulant is less than 2.5 mm, the water absorption rate is less than 0.25%, and it has strong adhesion to the silicon wafer. In order to make the size of the encapsulated chip meet the usage requirements, the encapsulant layer can also be polished to achieve the target size.

[0037] 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.

[0038] The raw materials used in the examples and comparative examples are as follows:

[0039] Epoxy resins: CELLOXIDE 2000 (Japanese CELLOXIDE 2021P);

[0040] MQ silicone resin: Vinyl phenyl MQ silicone resin MQ0012 from Hubei Yamed Biomedical Co., Ltd.;

[0041] Curing agents: methyltetrahydrophthalic anhydride; methylhexahydrophthalic anhydride;

[0042] Polydimethylsiloxane: Dow Corning PMX-200;

[0043] Accelerator: Ajinomoto PN40 or PN50 (Japan);

[0044] Leveling agents: HZ-1336 (main component: polyether-modified polydimethylsiloxane) from Guangzhou Haoliangda International Trade Co., Ltd.; HZ-1309, silicone leveling agent from Guangzhou Haoliangda International Trade Co., Ltd.

[0045] Surfactant: Japanese Sanopco polyether surfactant SN-WET 980 or SN-WET 366.

[0046] Example 1

[0047] By weight, the raw materials for printed film encapsulants include:

[0048] Spherical silica (3-25μm): 80%, spherical silica (1-5μm): 1%, epoxy resin CELLOXIDE2000: 8%, MQ silicone resin MQ0012: 1%, polydimethylsiloxane PMX-200: 1%, curing agent methyltetrahydrophthalic anhydride: 8%, surfactant SN-WET 980: 0.4%, accelerator PN40: 0.1%, leveling agent HZ-1336: 0.3%, carbon black: 0.2%;

[0049] The method for preparing the printed film encapsulant in this embodiment includes the following steps:

[0050] The weighed MQ silicone resin and polydimethylsiloxane are mixed at 80-100℃ for 20-30 minutes. After the mixture is homogeneous, a premix is ​​obtained.

[0051] Add weighed spherical silica (3-25μm), spherical silica (1-5μm), epoxy resin, curing agent, surfactant, accelerator, leveling agent, and carbon black to the premix, and mix evenly using a centrifugal mixer to obtain a mixture; wherein the operating parameters of the centrifugal mixer include: mixing time of 160-300s, rotation of 1200r / min, and revolution of 1500r / min;

[0052] The mixture is dispersed by a three-roll mill to obtain a uniformly dispersed slurry. The operating parameters of the three-roll mill include: feed gap of 65-95μm and discharge gap of 40-60μm.

[0053] The slurry is vacuum degassed using a centrifugal mixer. The operating parameters of the centrifugal mixer include: vacuum degassed time of 70-90s, rotation of 1200r / min, and revolution of 1500r / min, resulting in a low-warpage and easily grindable printable film sealant.

[0054] Example 2

[0055] By weight, the raw materials for printed film encapsulants include:

[0056] Spherical silica (3-25μm): 82%, spherical silica (1-5μm): 1%, epoxy resin CELLOXIDE2021P: 6%, MQ silicone resin MQ0012: 2%, polydimethylsiloxane PMX-200: 2%, curing agent methylhexahydrophthalic anhydride: 6%, surfactant SN-WET 366: 0.4%, accelerator PN50: 0.1%, leveling agent HZ-1309: 0.3%, carbon black: 0.2%;

[0057] The steps of the preparation method of the printed film sealant in this embodiment are the same as those in Embodiment 1.

[0058] Example 3

[0059] By weight, the raw materials for printed film encapsulants include:

[0060] Spherical silica (3-25μm): 83%, spherical silica (1-5μm): 2%, epoxy resin CELLOXIDE2000: 5%, MQ silicone resin MQ0012: 1%, polydimethylsiloxane PMX-200: 1%, curing agent methyltetrahydrophthalic anhydride: 7%, surfactant SN-WET 980: 0.4%, accelerator PN40: 0.1%, leveling agent HZ-1336: 0.3%, carbon black: 0.2%;

[0061] The steps of the preparation method of the printed film sealant in this embodiment are the same as those in Embodiment 1.

[0062] Example 4

[0063] By weight, the raw materials for printed film encapsulants include:

[0064] Spherical silica (3-25μm): 85%, spherical silica (1-5μm): 1.5%, epoxy resin CELLOXIDE2000: 5.5%, MQ silicone resin MQ0012: 1%, polydimethylsiloxane PMX-200: 1%, curing agent methylhexahydrophthalic anhydride: 5%, surfactant SN-WET 366: 0.4%, accelerator PN50: 0.1%, leveling agent HZ-1336: 0.3%, carbon black: 0.2%;

[0065] The steps of the preparation method of the printed film sealant in this embodiment are the same as those in Embodiment 1.

[0066] Comparative Example 1

[0067] By weight, the raw materials for printed film encapsulants include:

[0068] Spherical silica (3-25μm): 81%, spherical silica (1-5μm): 1%, epoxy resin CELLOXIDE2000: 8%, MQ silicone resin MQ0012: 1%, curing agent methyltetrahydrophthalic anhydride: 8%, surfactant SN-WET 980: 0.4%, accelerator PN40: 0.1%, leveling agent HZ-1336: 0.3%, carbon black: 0.2%;

[0069] The preparation method of the printed encapsulant in this comparative example includes the following steps:

[0070] Add weighed spherical silica (3-25μm), spherical silica (1-5μm), epoxy resin, curing agent, surfactant, accelerator, leveling agent, and carbon black to the weighed MQ silicone resin, and mix evenly using a centrifugal mixer to obtain a mixture; wherein the operating parameters of the centrifugal mixer are: mixing time of 160-300s, rotation of 1200r / min, and revolution of 1500r / min.

[0071] The mixture is dispersed by a three-roll mill to obtain a uniformly dispersed slurry. The operating parameters of the three-roll mill include: feed gap of 65-95μm and discharge gap of 40-60μm.

[0072] The slurry is vacuum degassed using a centrifugal mixer. The operating parameters of the centrifugal mixer include: vacuum degassed time of 70-90s, rotation of 1200r / min, and revolution of 1500r / min, resulting in a low-warpage and easily grindable printable film sealant.

[0073] Comparative Example 2

[0074] By weight, the raw materials for printed film encapsulants include:

[0075] Spherical silica (3-25μm): 84%, spherical silica (1-5μm): 1.5%, epoxy resin CELLOXIDE2021P: 6%, polydimethylsiloxane PMX-200: 2%, curing agent methylhexahydrophthalic anhydride: 6%, surfactant SN-WET366: 0.4%, accelerator PN50: 0.1%, leveling agent HZ-1336: 0.3%, carbon black: 0.2%;

[0076] The preparation method of the printed encapsulant in this comparative example includes the following steps:

[0077] Add weighed spherical silica (3-25μm), spherical silica (1-5μm), epoxy resin, curing agent, surfactant, accelerator, leveling agent, and carbon black to weighed polydimethylsiloxane, and mix evenly using a centrifugal mixer to obtain a mixture; wherein the operating parameters of the centrifugal mixer include: mixing time of 160-300s, rotation of 1200r / min, and revolution of 1500r / min.

[0078] The mixture is dispersed by a three-roll mill to obtain a uniformly dispersed slurry. The operating parameters of the three-roll mill include: feed gap of 65-95μm and discharge gap of 40-60μm.

[0079] The slurry is vacuum degassed using a centrifugal mixer. The operating parameters of the centrifugal mixer include: vacuum degassed time of 70-90s, rotation of 1200r / min, and revolution of 1500r / min, resulting in a low-warpage and easily grindable printable film sealant.

[0080] Comparative Example 3

[0081] By weight, the raw materials for printed film encapsulants include:

[0082] Spherical silica (3-25μm): 79%, spherical silica (1-5μm): 1%, epoxy resin CELLOXIDE2000: 9%, MQ silicone resin MQ0012: 3%, polydimethylsiloxane PMX-200: 3%, curing agent methyltetrahydrophthalic anhydride: 4%, surfactant SN-WET 980: 0.4%, accelerator PN50: 0.1%, leveling agent HZ-1309: 0.3%, carbon black: 0.2%;

[0083] The preparation method of the printed film sealant in this comparative example follows the same steps as in Example 1.

[0084] Comparative Example 4

[0085] By weight, the raw materials for printed film encapsulants include:

[0086] Spherical silica (3-25μm): 85.5%, spherical silica (1-5μm): 1%, epoxy resin CELLOXIDE2021P: 3%, MQ silicone resin MQ0012: 2.5%, polydimethylsiloxane PMX-200: 3%, curing agent methylhexahydrophthalic anhydride: 4%, surfactant SN-WET 980: 0.4%, accelerator PN50: 0.1%, leveling agent HZ-1336: 0.3%, carbon black: 0.2%;

[0087] The preparation method of the printed film sealant in this comparative example follows the same steps as in Example 1.

[0088] Comparative Example 5

[0089] By weight, the raw materials for printed film encapsulants include:

[0090] Spherical silica (3-25μm): 81%, epoxy resin CELLOXIDE 2000: 8%, MQ silicone resin MQ0012: 1%, polydimethylsiloxane PMX-200: 1%, curing agent methyltetrahydrophthalic anhydride: 8%, surfactant SN-WET 980: 0.4%, accelerator PN40: 0.1%, leveling agent HZ-1336: 0.3%, carbon black: 0.2%;

[0091] The preparation method of the printed film sealant in this comparative example follows the same steps as in Example 1.

[0092] The printed film encapsulants provided in Examples 1-4 and Comparative Examples 1-5 were tested, and the specific test procedures are as follows:

[0093] 1. Viscosity test: The viscosity was measured using a digital rotational viscometer. Test conditions: 14# rotor, 20 r / min rotation speed, and 25℃.

[0094] 2. Wafer warpage test: Apply 12-14g of adhesive material to the wafer and coat it evenly at room temperature. Place it in an oven at 180℃ for 2 hours and then allow it to cool naturally to room temperature. Use a vernier caliper to measure the wafer warpage height.

[0095] 3. Silicon wafer adhesion test: The sample is poured into a pudding mold with a diameter of 3mm and a height of 2mm. One end of the poured sample is in contact with the silicon wafer. The silicon wafer is fixed to the pudding mold. After curing at 180℃ for 2h, the pudding mold is removed, the sample is taken out, and the push test is performed.

[0096] 4. Water absorption test: The water absorption rate of the film sealant sample cured at 180℃ / 2h is tested after being kept at 130℃ and 85%RH for 96 hours.

[0097] 5. Grinding wheel consumption: The front side of the cured wafer is ground using a wafer grinder, and the consumption of the grinding wheel of the grinder is recorded.

[0098] The test results are shown in Table 1 below:

[0099] Table 1 Test Results

[0100]

[0101] As can be seen from the table above:

[0102] (1) Examples 1-4 use specific formulation ratios to prepare film sealants that are easy to print and encapsulate. After curing, they have low warpage and water absorption, high silicon wafer adhesion, and low consumption of grinding wheels when ground to the target size using a grinder.

[0103] (2) In Comparative Example 1, polydimethylsiloxane was not used, and the prepared film sealant had a higher water absorption rate and a higher consumption of grinding wheels.

[0104] (3) In Comparative Example 2, MQ silicone resin was not used, and the prepared film sealant had a large warpage, which was not conducive to providing effective protection for chip packaging.

[0105] (4) Compared with Example 1, Comparative Example 3 had a lower amount of large-diameter spherical silica and a higher amount of alicyclic epoxy resin, MQ silicone resin and polydimethylsiloxane. The silicon wafer adhesion of the prepared encapsulant was significantly reduced, and the water absorption, warpage and consumption of the polishing wheel were all increased. In Comparative Example 4, the amount of large-diameter spherical silica was higher and the amount of alicyclic epoxy resin was lower. The silicon wafer adhesion of the prepared encapsulant was significantly reduced, and the water absorption, warpage and consumption of the polishing wheel were all increased, which was not conducive to chip encapsulation. In Comparative Example 5, only large-diameter spherical silica was used and no small-diameter spherical silica was added. The various properties of the prepared encapsulant were reduced.

[0106] In summary, the film sealant prepared using the specific formulation ratio of this application has a lower water absorption rate and warpage, and when ground to the target size using a grinder, the wear on the grinding wheel is minimized.

[0107] 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.

[0108] 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 the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0109] 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 and easily grindable printable film encapsulant, characterized in that, The printed film sealant comprises the following components by weight percentage: 81%-88% filler, 4%-8% alicyclic epoxy resin, 1%-2% MQ silicone resin, 1%-2% polydimethylsiloxane, 5%-9% anhydride curing agent, 0.3%-0.5% surfactant, 0.1%-0.2% accelerator, 0.2%-0.4% leveling agent, and 0.1%-0.2% carbon black; wherein the filler is composed of a first spherical silica and a second spherical silica, the first spherical silica having a particle size of 3-25 μm, and the second spherical silica having a particle size of 1-5 μm; The first spherical silica has a mass percentage of 80%-85%, and the second spherical silica has a mass percentage of 1%-2%.

2. The low-warpage and easily grindable printable film encapsulant according to claim 1, characterized in that, The MQ ratio of the MQ silicone resin is 0.70-0.

75.

3. The low-warpage and easily grindable printable film encapsulant according to claim 1, characterized in that, The viscosity of the polydimethylsiloxane is 10-50 cs.

4. The low-warpage and easily grindable printable film encapsulant according to claim 1, characterized in that, The surfactant has a mass percentage of 0.4%, the accelerator has a mass percentage of 0.1%, the leveling agent has a mass percentage of 0.3%, and the carbon black has a mass percentage of 0.2%.

5. The low-warpage and easily grindable printable film encapsulant according to claim 1, characterized in that, The surfactants include polyether surfactants.

6. The low-warpage and easily grindable printable film encapsulant according to claim 1, characterized in that, The leveling agent includes an organosilicon leveling agent.

7. A method for preparing a low-warpage and easily grindable printable film encapsulant, characterized in that, The preparation method includes: Accurately weigh each component of the raw material in the low-warpage and easily grindable printable film sealant as described in any one of claims 1-6; Weigh out the MQ silicone resin and polydimethylsiloxane and mix them evenly at a mixing temperature of 80-100℃ for 20-30 minutes to obtain a premix. Add the weighed filler, alicyclic epoxy resin, acid anhydride curing agent, surfactant, accelerator, leveling agent and carbon black to the premix, mix evenly to obtain the mixture; The mixture is dispersed using a three-roll mill to obtain a uniformly dispersed slurry. The slurry is vacuum degassed to obtain a printable film sealant with low warpage and easy grinding.

8. A packaging structure comprising a chip and a molding compound bonded to the six sides of the chip, characterized in that, The molding sealant is formed by curing the low-warpage and easily grindable printed film sealant as described in any one of claims 1-6, with a curing temperature of 180°C and a curing time of 2 hours.

9. The packaging structure according to claim 8, characterized in that, The warpage of the printed film sealant after curing is less than 2.5 mm, and the water absorption rate is less than 0.25%.

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