Liquid epoxy molding compound for improving glue overflow on back side of substrate, method and application thereof

Abstract

The application discloses a liquid epoxy plastic packaging material for improving glue overflow on the back of a substrate and a method and application thereof, and relates to the technical field of electronic packaging materials. The liquid epoxy plastic packaging material comprises the following components in percentage by mass: 83-88% of micron-sized silicon dioxide, 0.2-0.8% of nano-sized silicon dioxide, 4-7% of an epoxy resin, 0.4-1.0% of a multi-functional epoxy active diluent, 6-8% of a curing agent, 0.2-0.8% of a stress release agent, 0.2-0.3% of a catalyst and 0.1-0.2% of carbon black. The silicon hydroxyls on the surface of the nano-sized silicon dioxide are used to construct a three-dimensional hydrogen bond network structure in the epoxy resin system, so as to improve the rheological viscosity of the liquid epoxy plastic packaging material. The multi-functional epoxy active diluent is used to make the epoxy resin system change from a viscous liquid to an elastic gel state more quickly, thereby limiting the glue liquid flow time. The flowability of the liquid epoxy plastic packaging material is adjusted by using the nano-sized silicon dioxide and the multi-functional epoxy active diluent, so as to inhibit glue overflow on the back during the packaging process of the liquid epoxy plastic packaging material and improve the reliability of device packaging.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic packaging materials, and particularly relates to a liquid epoxy plastic packaging material for improving overflow of the back surface of a substrate, a method and application thereof. BACKGROUND

[0002] In advanced packaging technology, the continuous reduction of micro-bump interconnection pitch puts forward higher requirements for the flowability and filling property of liquid epoxy plastic packaging materials. In order to ensure defect-free filling in ultra-fine pitch structures, the liquid epoxy plastic packaging material needs to have an ultra-long flow length retention capability, but this property also increases the difficulty of rheological control of the material during hot pressing. When the viscosity of the liquid epoxy plastic packaging material is too low, the glue liquid is slightly bled (bleeding) to the back surface of the substrate through capillary action, forming a thin film-like diffusion that is difficult to detect, which seriously affects the packaging reliability and subsequent processes.

[0003] The traditional overflow problem is usually manifested as obvious glue accumulation, while the slight bleeding is more hidden, and its characteristics include: (1) occurring in non-sealing areas, which is not easy to be found by conventional detection means; (2) the glue is diffused in the form of a thin film rather than forming a protruding structure; (3) the negative impact on subsequent bonding, mounting and other processes has a lagging nature, which may cause fatal defects such as interface bonding force reduction, signal transmission abnormality, etc.

[0004] The essence of the slight bleeding defect problem is closely related to the rheological behavior of the liquid epoxy plastic packaging material, and the main causes include: (1) the content of low molecular weight components is too high, which migrates to the interface and forms a micro-permeation channel during hot pressing; (2) the material lacks thixotropy, and the anti-flowing ability is weak at the viscosity trough period, which cannot effectively inhibit capillary bleeding; (3) the curing reaction is delayed, which prolongs the viscosity trough period and expands the bleeding time, and aggravates the capillary bleeding of the glue. The existing packaging materials and processes cannot effectively inhibit slight bleeding while ensuring high flowability, therefore, how to provide a liquid epoxy plastic packaging material for improving overflow of the back surface of a substrate to balance the flowability and anti-slight bleeding performance of the liquid epoxy plastic packaging material is a technical problem that needs to be solved by those skilled in the art. SUMMARY

[0005] The present application aims to provide a liquid epoxy plastic packaging material for improving overflow of the back surface of a substrate, a method and application thereof, to at least solve the above-mentioned technical problem.

[0006] To achieve the above object, the present application provides a liquid epoxy plastic sealing material for improving back glue overflow of a substrate, which comprises the following components in percentage by mass: 83-88% of micron-sized silicon dioxide, 0.2-0.8% of nano silicon dioxide, 4-7% of epoxy resin, 0.4-1.0% of multifunctional epoxy active diluent, 6-8% of curing agent, 0.2-0.8% of stress release agent, 0.2-0.3% of catalyst, and 0.1-0.2% of carbon black; the maximum particle size of the micron-sized silicon dioxide is less than 28 μm, and the average particle size is 6-8 μm; the epoxy resin comprises at least one of naphthalene type epoxy resin and alicyclic epoxy resin.

[0007] In the first aspect, the multifunctional epoxy active diluent comprises a difunctional epoxy active diluent or a trifunctional epoxy active diluent.

[0008] In the first aspect, the curing agent comprises methyl tetrahydrophthalic anhydride or methyl hexahydrophthalic anhydride.

[0009] In the first aspect, the product model of the stress release agent is F351.

[0010] In the first aspect, the catalyst comprises benzyl dimethyl amine or 2-ethyl-4-methyl imidazole.

[0011] In the first aspect, the model of the nano silicon dioxide is QSG30 or A200.

[0012] The present application provides a method for improving back glue overflow of a substrate after operation of a liquid epoxy plastic sealing material, which comprises the following steps: S1, adding each component of the raw material of the liquid epoxy plastic sealing material according to the first aspect into a stirring cup in proportion, and mixing uniformly to obtain a first slurry; S2, transferring the first slurry to a three-roll grinding machine for dispersion treatment to obtain a second slurry; S3, performing vacuum degassing on the second slurry to obtain a third slurry; and S4, extruding the third slurry on a device to be packaged, and performing vacuum hot pressing to complete the packaging of the device to be packaged.

[0013] In the second aspect, in S2, the feeding gap of the three-roll grinding machine is 90-150 μm, and the discharging gap is 60-120 μm.

[0014] In the second aspect, in S3, the vacuum degassing time is 60-90 s.

[0015] The present application provides an application of the liquid epoxy plastic sealing material for improving back glue overflow of a substrate according to the first aspect in integrated circuit packaging.

[0016] Beneficial effects:

[0017] The application provides a liquid epoxy plastic sealing material for improving back overflow of a substrate, which comprises the following components in percentage by mass: 83-88% of micron-sized silicon dioxide, 0.2-0.8% of nanometer-sized silicon dioxide, 4-7% of epoxy resin, 0.4-1.0% of multifunctional epoxy active diluent, 6-8% of curing agent, 0.2-0.8% of stress release agent, 0.2-0.3% of catalyst and 0.1-0.2% of carbon black; the silicon dioxide is used to build a three-dimensional hydrogen bond network structure in the epoxy resin system by virtue of the silicon hydroxyls on the surface of the nanometer-sized silicon dioxide, so as to improve the rheological viscosity of the liquid epoxy plastic sealing material and inhibit the back overflow of the substrate; the multifunctional epoxy active diluent is used to make the epoxy resin system change from viscous liquid to elastic gel state more quickly, so as to limit the flow time and range of the liquid epoxy plastic sealing material in the low viscosity state, reduce the overflow on the back of the substrate and improve the reliability of device packaging. BRIEF DESCRIPTION OF DRAWINGS

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

[0019] Figure 1 The flowchart of the method for improving back overflow of a substrate after operation of a liquid epoxy plastic sealing material provided by the present application is shown in the figure.

[0020] Figure 2 The schematic diagram of the test method for warping of a liquid epoxy plastic sealing material in the present application is shown in the figure.

[0021] Figure 3 The schematic diagram of the test method for back overflow length of a liquid epoxy plastic sealing material after hot pressing in the present application is shown in the figure.

[0022] Reference signs:

[0023] 1, upper plate of vacuum vulcanizing machine; 2, liquid epoxy plastic sealing material; 3, silicon wafer; 4, lower plate of vacuum vulcanizing machine; 5, liquid epoxy plastic sealing material after curing; 6, glass wafer; 7, liquid epoxy plastic sealing material after vacuum hot pressing; a, warping height; b, back overflow length. DETAILED DESCRIPTION

[0024] The advantages and various effects of the present application will be more clearly presented hereinafter in conjunction with specific embodiments and examples. Those skilled in the art should understand that these embodiments and examples are used to illustrate the present application, rather than limit the present application.

[0025] Throughout the specification, unless otherwise specifically indicated, the terms used herein are understood as having the meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs. If there is a conflict, the present specification takes precedence.

[0026] Unless otherwise specifically indicated, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or obtained by existing methods.

[0027] The liquid epoxy plastic packaging material for improving back overflow of the substrate provided by the present application comprises the following components in mass percentage: 83%-88% of micron-sized silicon dioxide, 0.2%-0.8% of nano-sized silicon dioxide, 4-7% of epoxy resin, 0.4%-1.0% of multifunctional epoxy active diluent, 6%-8% of curing agent, 0.2%-0.8% of stress release agent, 0.2%-0.3% of catalyst, and 0.1%-0.2% of carbon black. The maximum particle size of the micron-sized silicon dioxide is less than 28 μm, and the average particle size is 6-8 μm. The epoxy resin comprises at least one of naphthalene type epoxy resin and alicyclic epoxy resin.

[0028] Specifically, the liquid epoxy plastic packaging material for improving back overflow of the substrate provided by the present application comprises the following components in mass percentage: 83%-88% of micron-sized silicon dioxide, 0.2%-0.8% of nano-sized silicon dioxide, 4-7% of epoxy resin, 0.4%-1.0% of multifunctional epoxy active diluent, 6%-8% of curing agent, 0.2%-0.8% of stress release agent, 0.2%-0.3% of catalyst, and 0.1%-0.2% of carbon black. The silicon hydroxyl-rich surface of the nano-sized silicon dioxide is used to construct a three-dimensional hydrogen bond network structure in the epoxy resin system, so as to improve the rheological viscosity of the liquid epoxy plastic packaging material, thereby inhibiting the back overflow of the substrate. The multifunctional epoxy active diluent is used to make the epoxy resin system change from viscous liquid to elastic gel state more quickly, thereby limiting the flow time and range of the liquid epoxy plastic packaging material in the low viscosity state, reducing the transition flow and overflow on the back of the substrate. The flowability of the liquid epoxy plastic packaging material is adjusted by adding the nano-sized silicon dioxide and the multifunctional epoxy active diluent, so as to inhibit the back overflow of the liquid epoxy plastic packaging material during the packaging process, and improve the reliability of the device packaging.

[0029] In some possible embodiments, the multi-functional epoxy reactive diluent includes a di-functional epoxy reactive diluent or a tri-functional epoxy reactive diluent.

[0030] In the present application, the multi-functional epoxy reactive diluent is used to participate in the curing reaction to form a high cross-linking network structure, which helps the liquid epoxy encapsulant to quickly shape, thereby inhibiting overflow and improving the anti-micro-bleeding property of the liquid epoxy encapsulant.

[0031] In some possible embodiments, the curing agent includes methyl tetrahydrophthalic anhydride or methyl hexahydrophthalic anhydride.

[0032] In some possible embodiments, the stress release agent has a product model of F351.

[0033] The stress release agent with the product model of F351 in the present application has a glassy polymer shell and a rubbery polymer core, which absorbs the internal stress generated by the curing shrinkage by using the swelling pre-gel characteristics, reduces the interface stress concentration, improves the wettability, has a low spreading speed in the hot pressing process, thereby inhibiting the upward climbing of the epoxy encapsulant along the back of the substrate and improving the back overflow phenomenon. That is, the stress release agent with the F351 model in the liquid epoxy encapsulant in the present application reduces the back overflow length of the liquid epoxy encapsulant in the device packaging process by the unique interface toughening and thermal stress regulation mechanism, thereby improving the reliability of the device packaging.

[0034] In some possible embodiments, the catalyst includes benzyl dimethyl amine or 2-ethyl-4-methyl imidazole.

[0035] In some possible embodiments, the nano-silica has a model of QSG30 or A200.

[0036] The nano-silica is used as a functional filler in the liquid epoxy encapsulant, which can offset the chemical shrinkage during the curing of the epoxy resin by the unique physical and chemical effects, so as to change the thixotropy coefficient of the liquid epoxy encapsulant, thereby significantly improving the back overflow problem in the packaging process. In the present application, the rheological viscosity of the liquid epoxy encapsulant can be adjusted by adjusting the proportion of the nano-silica, and the viscosity of the epoxy system can be improved by forming a three-dimensional hydrogen bond network structure by the silicon hydroxyl groups on the surface of the nano-silica. The high viscosity can effectively prevent the gel from flowing to the back of the substrate. Meanwhile, under the hot pressing condition, the three-dimensional hydrogen bond network structure is temporarily destroyed, the viscosity of the system is rapidly reduced, thereby fully filling the small gaps, and after the pressure is removed, the nano-silica reconstructs the three-dimensional network structure, the viscosity of the system is improved, thereby locking the shape and preventing subsequent overflow. Further, the epoxy resin generates system shrinkage during the curing, which causes the "suction effect" to pull the uncured glue to the back of the substrate, and the nano-silica acts as a rigid inorganic particle, which can partially offset the shrinkage stress and reduce the overall shrinkage rate of the system.

[0037] Based on one general inventive concept, the second aspect of the present application provides a method for improving backside overflow of liquid epoxy plastic encapsulation material after operation, the method comprising:

[0038] S1, proportionally adding each component of the raw material of the liquid epoxy plastic encapsulation material of the first aspect into a stirring cup and mixing uniformly to obtain a first slurry; using a centrifugal stirrer for stirring and mixing, the stirring time being 120-150 s, the revolution being 2400 r / min, and the rotation being 1100 r / min;

[0039] S2, transferring the first slurry to a three-roll grinder for dispersion treatment to obtain a second slurry; the feeding gap of the three-roll grinder being 90-150 μm, and the discharging gap being 60-120 μm;

[0040] S3, vacuum defoaming the second slurry to obtain a third slurry; using a centrifugal stirrer for stirring and mixing, the stirring time being 60-90 s, the rotation being 65-130 r / min, and the revolution being 1300 r / min;

[0041] S4, extruding the third slurry on a device to be packaged, and completing the packaging of the device to be packaged through vacuum hot pressing.

[0042] Based on one general inventive concept, the third aspect of the present application provides the application of the liquid epoxy plastic encapsulation material for improving backside overflow of a substrate in integrated circuit packaging.

[0043] The application of the liquid epoxy plastic encapsulation material provided in the first aspect of the present application in integrated circuit packaging can inhibit the length of backside overflow of a substrate after packaging, thereby ensuring the packaging reliability, so as to facilitate the subsequent process.

[0044] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods in the following examples without specific conditions are generally determined according to the national standards. If there is no corresponding national standard, the international standard, the conventional condition, or the condition suggested by the manufacturer is used.

[0045] The raw materials used in the examples and comparative examples are as follows:

[0046] Micron-sized silicon dioxide: the average particle size being 6-8 μm, and the maximum particle size being not more than 28 μm;

[0047] Nanosized silicon dioxide: AEROSIL® A200; QSG 30;

[0048] Epoxy resin: alicyclic epoxy resin SYNASIA S-06E; naphthalene type epoxy resin 2,2'-[1,6-naphthalene di(oxy methylene)] dioxyoxane;

[0049] Epoxy reactive diluent: EX-192 (monofunctional); JY-E205 (difunctional); JY-E303 (trifunctional);

[0050] Curing agent: methyl tetrahydrophthalic anhydride; methyl hexahydrophthalic anhydride;

[0051] Stress release agent: F351;

[0052] Catalyst: benzyl dimethyl amine (BDMA); 2-ethyl-4-methyl imidazole (2E4MZ);

[0053] Dye: carbon black.

[0054] Example 1

[0055] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0056] Micron-sized silica: 85.9%, nanometer-sized silica QSG30: 0.2%, naphthalene type epoxy resin: 5.7%, epoxy reactive diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.3%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0057] Example 2

[0058] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0059] Micron-sized silica: 85.3%, nanometer-sized silica QSG30: 0.8%, naphthalene type epoxy resin: 5.7%, epoxy reactive diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.3%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0060] Example 3

[0061] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0062] Micron-sized silica: 85.3%, nanometer-sized silica A200: 0.8%, naphthalene type epoxy resin: 5.7%, epoxy reactive diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.3%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0063] Example 4

[0064] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0065] Micron silica: 85.6%, nanometer silica QSG30: 0.5%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E303: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.3%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0066] Example 5

[0067] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0068] Micron silica: 84.8%, nanometer silica QSG30: 0.8%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.8%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0069] Example 6

[0070] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0071] Micron silica: 86.1%, nanometer silica QSG30: 0.8%, naphthalene type epoxy resin: 2.3%, alicyclic epoxy resin S-06E: 2.1%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 7.0%, stress release agent F351: 0.6%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0072] Example 7

[0073] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0074] Micron silica: 84.8%, nanometer silica QSG30: 0.8%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.8%, carbon black: 0.1%, catalyst BDMA: 0.2%.

[0075] Example 8

[0076] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0077] Micron silica: 85.85%, nanometer silica QSG30: 0.40%, naphthalene type epoxy resin: 5.50%, epoxy active diluent JY-E205: 0.43%, methyl tetrahydrophthalic anhydride: 7.22%, stress release agent F351: 0.30%, carbon black: 0.10%, catalyst 2E4MZ: 0.20%.

[0078] Example 9

[0079] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0080] Micron silica: 85.9%, nanometer silica QSG30: 0.2%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl hexahydrophthalic anhydride: 6.8%, stress release agent F351: 0.3%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0081] Comparative Example 1

[0082] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0083] Micron silica: 85.8%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.6%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0084] Comparative Example 2

[0085] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0086] Micron silica: 84.3%, nanometer silica QSG30: 1.5%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.6%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0087] Comparative Example 3

[0088] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0089] Micron silica: 84.3%, nanometer silica A200: 1.5%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.6%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0090] Comparative Example 4

[0091] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0092] Micron silica: 85.9%, nanometer silica QSG30: 0.5%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0093] Comparative Example 5

[0094] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0095] Micron silica: 84.4%, nanometer silica QSG30: 0.5%, naphthalene type epoxy resin: 5.7%, epoxy active diluent JY-E205: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 1.5%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0096] Comparative Example 6

[0097] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0098] Micron silica: 85.6%, nanometer silica QSG30: 0.5%, naphthalene type epoxy resin: 6.0%, methyl tetrahydrophthalic anhydride: 7.0%, stress release agent F351: 0.6%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0099] Comparative Example 7

[0100] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0101] Micron silica: 86.2%, naphthalene type epoxy resin: 6.3%, methyl tetrahydrophthalic anhydride: 7.2%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0102] Comparative Example 8

[0103] The raw materials of the liquid epoxy encapsulating material include, in mass percentage:

[0104] Micron silica: 85.6%, nanometer silica QSG30: 0.5%, naphthalene type epoxy resin: 5.7%, epoxy active diluent EX-192: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.3%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0105] Comparative Example 9

[0106] The raw materials of the liquid epoxy molding compound include, in percentage by mass:

[0107] Micron silica: 85.6%, nano silica QSG30: 0.5%, naphthalene type epoxy resin: 5.7%, silane coupling agent KH-540: 0.8%, methyl tetrahydrophthalic anhydride: 6.8%, stress release agent F351: 0.3%, carbon black: 0.1%, catalyst 2E4MZ: 0.2%.

[0108] The formula proportions provided by the above Examples 1-9 and Comparative Examples 1-9 are prepared into liquid epoxy molding compounds according to the following experimental steps:

[0109] (1) The raw materials are weighed according to the formula proportions of the respective examples and comparative examples, and are added to a stirring cup and mixed uniformly by a centrifugal mixer, with a revolution of 2400 r / min and a rotation of 1100 r / min, and a stirring time of 150 s;

[0110] (2) The uniformly mixed slurry is added to a three-roll mill for dispersion treatment, to obtain uniformly dispersed slurry, wherein the feed gap of the three-roll mill is 150 μm and the discharge gap is 60 μm;

[0111] (3) The uniformly dispersed slurry is vacuum degassed by a centrifugal mixer, to obtain a liquid molding compound, wherein the revolution of the centrifugal mixer is 1300 r / min and the rotation is 130 r / min, and the stirring time is 60 s.

[0112] The liquid epoxy molding compounds prepared in Examples 1-9 and Comparative Examples 1-9 are tested, and the specific testing process is as follows:

[0113] 1. Viscosity test: measured by a digital rotary viscometer at 25°C;

[0114] 2. Warpage test method: 150 g of the liquid epoxy molding compound is extruded on a 12-inch silicon wafer (300 μm thick) and covered with a release film, and is placed on a vacuum curing machine carrier plate with a temperature set at 125°C, the carrier plate is controlled to be film combined, vacuum is extracted, and hot pressing is performed at a pressure of 3000 kN, with a pressing height set at 300 μm, and after 10 min of pressure retention, the sample after pressing is taken out, and the sample is placed in a 150°C vacuum drying oven for curing for 1 h, and after cooling, the height of warpage of one end of the liquid epoxy molding compound and the silicon wafer is measured, i.e. the material warpage value, as shown in FIG. 1. Figure 2

[0115] ​3. The test method for the back overflow length of glue: take 150g of liquid epoxy plastic encapsulating material and extrude it on a 12-inch glass sheet (750μm thick) with a release film on top, place it on a vacuum curing machine with a temperature setting of 125℃, control the film on the carrier plate, vacuumize, heat press with a pressure of 3000kN, set the pressing height to 300μm, take it out after 10min of pressure retention; measure the width of the overflow of the liquid epoxy plastic encapsulating material to the center of the glass sheet after cooling, which is the heat press overflow length of the liquid epoxy plastic encapsulating material, as shown in the attached Figure 3

[0116] The test results are shown in Table 1 below:

[0117] Table 1 Test results

[0118]

[0119] It should be noted that the liquid epoxy plastic encapsulating material provided by the present application will be extruded by instruments in the packaging process, and the normal operation requirements of the instruments are: the viscosity of the liquid epoxy plastic encapsulating material is less than 800Pa·s; when the viscosity is between 800-1200Pa·s, a wire drawing phenomenon will occur; and when the viscosity is greater than 1200Pa·s, an extrusion pressure alarm will occur.

[0120] From the experimental data in Table 1 above, it can be seen that the room temperature viscosity of the liquid epoxy plastic encapsulating material provided by the present application is less than 800Pa·s, which can meet the normal operation of commonly used equipment and instruments in industrial production; and after packaging and curing, the warpage and back overflow length of the liquid epoxy plastic encapsulating material meet the packaging requirements of electronic devices.

[0121] Finally, it should be noted that the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or equipment.

[0122] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0123] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.​

Claims

1. A liquid epoxy molding compound for improving glue overflow on the back side of a substrate, characterized in that, The liquid epoxy plastic encapsulating material is composed of the following components in percentage by mass: micron-sized silica 83-88%, nano-sized silica 0.2-0.8%, epoxy resin 4-7%, multifunctional epoxy active diluent 0.4-1.0%, curing agent 6-8%, stress release agent 0.2-0.8%, catalyst 0.2-0.3%, and carbon black 0.1-0.2%; The micron-sized silica has a maximum particle size of less than 28 μm and an average particle size of 6-8 μm; The epoxy resin is at least one of naphthalene-type epoxy resin and alicyclic epoxy resin; The multifunctional epoxy active diluent is a difunctional epoxy active diluent or a trifunctional epoxy active diluent; The nano-sized silica is of type QSG30 or A200; The stress release agent is of product type F351.

2. The liquid epoxy molding compound for improving glue overflow on the back surface of a substrate according to claim 1, wherein The curing agent includes methyl tetrahydrophthalic anhydride or methyl hexahydrophthalic anhydride.

3. The liquid epoxy molding compound for improving glue overflow on the back surface of a substrate according to claim 1, wherein The catalyst includes benzyl dimethyl amine or 2-ethyl-4-methyl imidazole.

4. A method for improving the backside epoxy overflow after liquid epoxy molding, characterized in that, The method comprises: S1, adding the raw materials of the liquid epoxy plastic encapsulating material according to any one of claims 1-3 into a stirring cup in proportion and mixing uniformly to obtain a first slurry; S2, transferring the first slurry to a three-roll grinder for dispersion treatment to obtain a second slurry; S3, vacuum deaerating the second slurry to obtain a third slurry; S4, extruding the third slurry on a device to be packaged and performing vacuum hot pressing to complete the packaging of the device to be packaged.

5. The method for improving the backside epoxy overflow after liquid epoxy molding according to claim 4, wherein, In S2, the entry gap of the three-roll grinder is 90-150 μm and the exit gap is 60-120 μm.

6. The method for improving the backside epoxy overflow after liquid epoxy molding according to claim 5, wherein, In S3, the vacuum deaeration time is 60-90 s.

7. Use of the liquid epoxy plastic encapsulating material for improving back overflow of a substrate according to any one of claims 1-3 in integrated circuit packaging.

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