Epoxy resin underfill adhesive and preparation method thereof

Abstract

The invention discloses an epoxy resin underfill adhesive. The epoxy resin underfill adhesive comprises epoxy resin, an inorganic filler, a curing agent and a coupling agent as shown in a formula (I), in the imgabs0 #, R is methyl or ethyl, and X comprises substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted cycloalkyl, and substituted or unsubstituted heterocyclic group; r'comprises a group capable of reacting with an epoxy system.The epoxy resin underfill adhesive disclosed by the invention has relatively long gelation time, relatively low viscosity, relatively good bonding strength and relatively good humidity and heat resistance.

Description

Technical Field

[0001] The present application relates to the technical field of bottom filling adhesives, and in particular to an epoxy resin bottom filling adhesive and a preparation method thereof. Background Art

[0002] In the related art, the moisture and heat resistance of epoxy resin composite materials is improved mainly by introducing moisture and heat resistant fillers, moisture and heat resistant resins and curing agents, but they are not suitable for the application process of bottom filling glue. The main manifestation is that the introduction of moisture and heat resistant fillers, moisture and heat resistant resins and curing agents will increase the viscosity of the bottom filling glue and deteriorate its fluidity, which cannot meet the low viscosity and good fluidity required in 2.5D packaging.

[0003] Therefore, it is necessary to provide a bottom filling adhesive with high bonding strength and good moisture and heat resistance. Summary of the invention

[0004] In view of this, the present application provides an epoxy resin bottom filling glue and a preparation method thereof, aiming to improve at least one of the above technical problems existing in the existing bottom filling glue.

[0005] In a first aspect, an embodiment of the present application provides an epoxy resin bottom filling adhesive, wherein the epoxy resin bottom filling adhesive comprises an epoxy resin, an inorganic filler, a curing agent, and a coupling agent represented by formula (I);

[0006]

[0007] Wherein, R is methyl or ethyl, X includes substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic group; R' includes a group capable of reacting with an epoxy system.

[0008] Optionally, the R' includes at least one of an amino group, an acryloxy group, an epoxy group, an ethoxycarbonyl group, a methoxy group, a vinyl group, and a dioxolane group.

[0009] Optionally, X includes substituted or unsubstituted phenyl, substituted or unsubstituted phenoxy, or substituted or unsubstituted C3-C10 cycloalkyl.

[0010] Optionally, the R' includes at least one of amino, acryloxy, epoxy, ethoxycarbonyl, methoxy, vinyl, and dioxolanyl; and the X includes substituted or unsubstituted phenyl, substituted or unsubstituted phenoxy, or substituted or unsubstituted C3-C10 cycloalkyl.

[0011] Optionally, the coupling agent includes (acryloyloxymethyl)phenylethyltrimethoxysilane, N-[[[2-(trimethoxysilyl)ethyl]phenyl]methyl]-1,2-ethylenediamine, 3-(3-aminophenoxy)propyltrimethoxysilane, m-aminophenyltrimethoxysilane, p-aminophenyltrimethoxysilane, phenacyloxypropyltrimethoxysilane, N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane, 3,5-dimethoxyphenyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, triethoxy-p-phenylethoxycarbonylsilane, trimethoxy(4-methoxyphenyl)silane, triethoxy(4-methoxyphenyl)silane, trimethoxy[3-(phenylamino)propyl]silane, anilinemethyltriethoxy Silane, styrylethyltrimethoxysilane, 4-[2-(trimethoxysilyl)ethyl]phenyl]2-methyl acrylate, allylphenylpropyltriethoxysilane, 3-(3-aminophenoxy)propyltrimethoxysilane, phenyltriethoxysilane, 4-triethoxysilylbiphenyl, 3-cyclopentadienylpropyltriethoxysilane, cyclopentanetrimethoxysilane, ethylphenethyltrimethoxysilane, triethoxy-p-phenylethoxycarbonylsilane, 3,4-methylenedioxyphenyltriethoxysilane, 1-naphthyltriethoxysilane, 1-naphthyltrimethoxysilane, 9-phenanthrenyltriethoxysilane, trimethoxy(2-phenylethyl)silane, triethoxy-p-phenylmethylsilane, p-tolyltrimethylsilane, p-(triethoxysilyl)acetophenone, 2-(3-triethoxysilylphenyl)-1,3-dioxolane, or a combination thereof.

[0012] Optionally, in parts by mass, the epoxy resin: the curing agent: the inorganic filler: the coupling agent is (15-35): (10-20): (50-70): (0.1-5).

[0013] Optionally, the mass fraction of the coupling agent is 0.5 to 2.5 parts; and / or

[0014] The epoxy resin bottom filling glue also includes a colorant, and the mass fraction of the colorant is 0.1 parts to 5 parts.

[0015] Optionally, the epoxy resin comprises a multifunctional epoxy resin; and / or

[0016] The curing agent comprises an aniline curing agent; and / or

[0017] The inorganic filler includes one or more of aluminum oxide, aluminum nitride, silicon powder, zinc oxide, boron nitride, and diamond; and / or

[0018] The particle size D50 of the inorganic filler is 50nm-5um.

[0019] Optionally, the epoxy equivalent of the multifunctional epoxy resin is 90 to 100; and / or

[0020] The viscosity of the multifunctional epoxy resin is 6.5 Pa·s to 7.3 Pa·s; and / or

[0021] The multifunctional epoxy resin includes one or more of multifunctional glycidyl ether and glycidyl amine epoxy resins; and / or

[0022] The aniline curing agent includes one or more of m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, diethyltoluenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane and derivatives thereof; and / or

[0023] The epoxy resin also includes a low-viscosity epoxy resin, and the viscosity of the low-viscosity epoxy resin is 100 mPa.s-3000 mPa.s.

[0024] Optionally, the glycidylamine epoxy resin includes one or more of 4.5-epoxycyclohexane-1.2-dicarboxylic acid diglycidyl ester, 4-(2,3-epoxypropoxy)-N,N-di(2,3-epoxypropyl)aniline, N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane, resorcinol formaldehyde tetraglycidyl ether, triglycidyl meta-aminophenol, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; and / or

[0025] The low viscosity epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol AD ​​epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and hydrogenated bisphenol A epoxy resin; and / or

[0026] Calculated by weight, the low-viscosity epoxy resin: the multifunctional epoxy resin is (5-15): (10-20).

[0027] A second aspect of the present application provides a method for preparing an epoxy resin underfill, the method comprising the following steps:

[0028] Providing epoxy resin, inorganic filler, curing agent and coupling agent represented by formula (I);

[0029] The epoxy resin, the inorganic filler and the coupling agent are mixed to obtain an epoxy mixture.

[0030] Optionally, the step of mixing the epoxy resin, the inorganic filler and the coupling agent to obtain an epoxy mixture comprises:

[0031] Adding epoxy resin, inorganic filler and the coupling agent into a reaction kettle, stirring and mixing to obtain a premix;

[0032] The obtained premix is ​​ground to obtain the epoxy mixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 It is a schematic diagram of the 2.5D packaging structure;

[0035] Figure 2 Typical silicon die and bottom fill glue layering diagram;

[0036] Figure 3 Schematic diagram of bonding strength test specimen;

[0037] Figure 4 This is a photo of the silicon substrate after the bonding strength of the sample in Example 1 was tested;

[0038] Figure 5 This is a photo of the silicon substrate after the bonding strength of the sample in Comparative Example 1 was tested;

[0039] Figure 6 This is a photo of the silicon substrate after the bonding strength of the sample in Comparative Example 2 was tested. DETAILED DESCRIPTION

[0040] The experimental examples described in this application are only part of the embodiments of this application, not all of the embodiments. All other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain this application, and are not used to limit this application.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0042] In the description of this application, the term "including" means "including but not limited to." The terms first, second, third, etc. are used merely as labels and do not impose numerical requirements or establish a sequence.

[0043] In this application, "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0044] In the present application, "at least one" means one or more, and "plurality" means two or more. "One or more", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0045] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0046] With the in-depth application of integrated circuits (ICs) in smart phones, the Internet of Things, automotive electronics, high-performance computing and other fields, IC integration is getting higher and higher, and components are developing towards miniaturization and multi-functions; therefore, more stringent requirements are put forward for IC packaging technology; in order to cope with the development of IC technology, various advanced packaging technologies have been designed and developed: system-level packaging, wafer-level packaging, 2.5D packaging, 2.1D packaging and 3D packaging technology; among them, 2.5D packaging technology with silicon interposer (such as attached Figure 1 As shown), it effectively enhances the communication between high-performance chips and reduces power consumption.

[0047] In 2.5D packaging, the reliability is more challenging due to the large area occupied by the silicon interposer, the diversified layout of the integrated chip, and the increased density of the connections between and through the chip. As a key packaging material for protecting solder balls and improving packaging reliability, the bottom filler needs to meet more stringent conditions when dealing with new and higher-density 2.5D packaging technology, such as higher glass transition temperature, better fluidity, smaller filler size, smaller overflow length, and larger filling area. The bottom filler has lower warpage requirements (for example, the warpage changes little or less under a larger filling area) to cope with the good filling of narrower spacing in 2.5D packaging. In addition, as the feature size of the device gradually decreases and the integration continues to increase, the requirements for the environmental aging resistance (high temperature and moisture resistance) of the bottom filler are getting higher and higher.

[0048] The service environment of the bottom filler in 2.5D / 3D packaging is becoming more and more complex. The interfaces contacted by Underfill1 (UF1) for 2.5D / 3D packaging include: liquid molding compound (LMC), Si-interposer, μ-bump, die sidewall, etc. And because 2.5D / 3D packaging is a wafer-level packaging process, the bottom filler will undergo a complex and changeable thermal process during the packaging process. If the interface bonding strength between the bottom filler and the silicon die side is insufficient, the following problems will occur: Figure 2 The interface delamination problem shown in the figure will continue to worsen after the thermal process, leading to device failure.

[0049] In the related art, the moisture and heat resistance of epoxy resin composite materials is improved mainly by introducing moisture and heat resistant fillers, moisture and heat resistant resins and curing agents, but they are not suitable for the application process of bottom filling glue. The main manifestation is that the introduction of moisture and heat resistant fillers, moisture and heat resistant resins and curing agents will increase the viscosity of the bottom filling glue and deteriorate its fluidity, which cannot meet the low viscosity and good fluidity required in 2.5D packaging. Therefore, it is necessary to provide a bottom filling glue with high bonding strength and good moisture and heat resistance.

[0050] In view of this, an embodiment of the present application provides an epoxy resin bottom filling adhesive, wherein the epoxy resin bottom filling adhesive comprises an epoxy resin, an inorganic filler, a curing agent, and a coupling agent represented by formula (I);

[0051]

[0052] Wherein, R is methyl or ethyl, X includes substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic group; R' includes a group capable of reacting with an epoxy system (i.e., epoxy resin and curing agent).

[0053] Exemplarily, X can be a rigid structure such as phenyl, cyclohexane, naphthyl, phenanthryl, biphenyl, etc., and R' is an amino, acryloxy, epoxy, ethoxycarbonyl, methoxy, vinyl, dioxolane, etc. The coupling agent in the embodiment of the present application contains an X group, and X is at least one rigid structure group of substituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic group, so that the coupling agent itself has good moisture and heat resistance, thus greatly improving the moisture and heat resistance of the material after the epoxy resin bottom filling glue in the present application is cured. At the same time, the selected coupling agent also carries a group R' that can react with the epoxy system. This coupling agent can participate in the cross-linking reaction of the epoxy system, and construct a cross-linking network of the coupling agent and the epoxy system at the molecular level, which is conducive to further improving the moisture and heat resistance of the bottom filling glue in the present application after curing.

[0054] In addition, the coupling agent in the present application also plays a role in bridging organic matter (such as epoxy resin and curing agent, etc.) and inorganic matter. 2 / Si 3 N 4 There is Si-OH on the surface of the interface, so when it comes into contact with the coupling agent, it can react to remove an R-OH and form a Si-O-Si bond, thereby improving the bonding between the bottom filler material and the inorganic Si / SiO 2 / Si 3 N 4 It should be noted that the inorganic Si / SiO 2 / Si 3 N 4 The interface is the inorganic interface where the bottom filler contacts the packaged device. Si refers to silicon, which is the main component of the die and the interposer. SiO 2 and Si 3 N 4 It is the main component of the passivation layer under the die. The interfaces formed by these materials are the interfaces that the bottom fill must contact during the application process.

[0055] Under high temperature and high humidity conditions, since the coupling agent in the present application has certain rigid groups (such as group X), the strength of the coupling agent itself will not decline; secondly, this rigid coupling agent undergoes a cross-linking reaction with the epoxy system, and the cross-linked network constructed will not break under high temperature and high humidity conditions. Therefore, the strength of the material body after the bottom filling glue in the present application is cured will not decline under high temperature and high humidity conditions. In addition, since the coupling agent has been cross-linked with the inorganic Si / SiO 2 / Si 3 N 4The interface constructs Si-O-Si bonds, and it is difficult for moisture to enter the interface between the bottom filling glue and the inorganic substrate after curing to destroy the interfacial bonding strength. In addition, under high temperature and high humidity conditions, water molecules will induce the remaining Si-OR on the coupling agent and the Si-OH on the inorganic interface to further react and dehydrate to form new Si-O-Si, thereby improving the bonding strength between the bottom filling glue and the inorganic interface after curing.

[0056] In summary, in the embodiments of the present application, by adding a coupling agent of formula (I) to the epoxy resin bottom filling glue, the bonding strength of the bottom filling glue after curing can be improved, and the moisture and heat resistance of the main material after the bottom filling glue is cured can be improved, and the moisture and heat resistance at the interface between the bottom filling glue and the inorganic substrate after curing can also be improved.

[0057] In some embodiments of the present application, the coupling agent includes (acryloyloxymethyl)phenylethyltrimethoxysilane (i.e., the compound shown in the following structure (6)), N-[[[2-(trimethoxysilyl)ethyl]phenyl]methyl]-1,2-ethylenediamine, 3-(3-aminophenoxy)propyltrimethoxysilane (i.e., the compound shown in the following structure (2)), m-aminophenyltrimethoxysilane, p-aminophenyltrimethoxysilane, phenacyloxypropyltrimethoxysilane, N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane, 3,5-dimethoxyphenyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (also the compound shown in the following structure (1)), triethoxy-p-phenylethoxycarbonylsilane (also the compound shown in the following structure (3)), trimethoxy(4-methoxyphenyl)silane (also the compound shown in the following structure (5)), triethoxy(4-methoxyphenyl)silane, trimethoxy[3-(phenylamino)propyl]silane, anilinemethyltriethoxysilane, styrylethyltrimethoxysilane, 4-[2-(trimethoxysilyl)ethyl]phenyl]2-methylacrylate, allylphenylpropyltriethoxysilane (also the compound shown in the following structure (7)),

[0058] 3-(3-aminophenoxy)propyltrimethoxysilane, phenyltriethoxysilane, 4-triethoxysilylbiphenyl, 3-cyclopentadienylpropyltriethoxysilane, cyclopentanetrimethoxysilane, ethylphenethyltrimethoxysilane, triethoxy-p-phenylethoxycarbonylsilane, 3,4-methylenedioxyphenyltriethoxysilane, 1-naphthyltriethoxysilane, 1-naphthyltrimethoxysilane, 9-phenanthrenyltriethoxysilane, trimethoxy(2-phenylethyl)silane, triethoxy-p-phenylmethylsilane, p-tolyltrimethylsilane, p-(triethoxysilyl)acetophenone, 2-(3-triethoxysilylphenyl)-1,3-dioxolane (i.e., the compound shown in the following structure (8)) or a combination thereof.

[0059] In some embodiments of the present application, the coupling agent includes at least one of the compounds shown in the following structures (1) to (8):

[0060]

[0061] In some embodiments of the present application, the epoxy resin: the curing agent: the inorganic filler: the coupling agent is (15-35): (10-20): (50-70): (0.1-5) by weight. In this way, the epoxy resin bottom filling glue provided in the embodiments of the present application can have a lower viscosity and higher bonding strength and moisture and heat resistance after curing.

[0062] Exemplarily, the mass fraction of epoxy resin in the epoxy resin bottom filling glue is 15 parts, 20 parts, 25 parts, 30 parts, 35 parts and the range between any two of the above values.

[0063] Exemplarily, the mass fraction of the curing agent in the epoxy resin bottom filling glue is 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, and the range between any two of the above values.

[0064] Exemplarily, the mass fraction of the inorganic filler in the epoxy resin bottom filling glue is 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, and the range between any two of the above values.

[0065] Exemplarily, the mass fraction of the coupling agent in the epoxy resin bottom filling glue is 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, 1.1 part, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.5 parts, 5 parts and the range between any two of the above values.

[0066] In some embodiments of the present application, the epoxy resin includes a multifunctional epoxy resin, and the curing agent includes an aniline curing agent. In this embodiment, the multifunctional epoxy resin and aniline curing agent system is selected to increase the crosslinking density of the epoxy resin, thereby increasing the glass transition temperature of the epoxy resin bottom filling glue after curing. Of course, in other embodiments of the present application, the epoxy resin and the curing agent can also be selected from other systems, which are not limited here.

[0067] It should be noted that the multifunctional epoxy resin in this application refers to an epoxy resin including three or more epoxy functional groups in the molecular structure. Exemplarily, the epoxy equivalent of the multifunctional epoxy resin is 90 to 100, and the viscosity of the multifunctional epoxy resin is 6.5Pa·s to 7.3Pa·s. For example, the epoxy equivalent of the multifunctional epoxy resin is 90, 92, 94, 96, 98, 100 and the range between any two of the above values. The viscosity of the multifunctional epoxy resin is 6.5Pa·s, 6.7Pa·s, 6.9Pa·s, 7.1Pa·s, 7.3Pa·s and the range between any two of the above values. It should be noted that, unless otherwise specified, the viscosity in this application refers to the viscosity at 25°C.

[0068] In some embodiments of the present application, the multifunctional epoxy resin is one or more compositions of multifunctional glycidyl ether and glycidyl amine epoxy resins.

[0069] Exemplarily, the glycidylamine epoxy resin includes, but is not limited to, one or more combinations of 4.5-epoxycyclohexane-1.2-dicarboxylic acid diglycidyl ester, 4-(2,3-epoxypropoxy)-N,N-di(2,3-epoxypropyl)aniline (AG-90 epoxy resin), N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane (AG-80 epoxy resin), resorcinol formaldehyde tetraglycidyl ether (F-76), triglycidyl meta-aminophenol, and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0070] Exemplarily, the aniline curing agent is selected from one or more combinations of m-phenylenediamine (MPD), diaminodiphenylmethane (DDM), diaminodiphenyl sulfone (DDS), diethyltoluenediamine (DETDA), 3,3'-diethyl-4,4'-diaminodiphenylmethane and derivatives thereof.

[0071] In some embodiments of the present application, the inorganic filler includes one or more of aluminum oxide, aluminum nitride, silicon powder, zinc oxide, boron nitride, and diamond. Exemplarily, the inorganic filler is silicon powder.

[0072] In some embodiments of the present application, the particle size D50 of the inorganic filler is 50nm-5um. For example, the particle size of the inorganic filler is 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1um, 2um, 3um, 4um, 5um and the range between any two of the above values.

[0073] It should be noted that for advanced packaged devices, the distance between the die and the RDL is less than 40 microns. The filler D50 particle size in the epoxy resin bottom filler in this application is less than 5um. When used as a bottom filler to package the device, it can better fill the narrow distance in the packaged device (for example, the gap between the die and the RDL).

[0074] In some embodiments of the present application, the epoxy resin includes a multifunctional epoxy resin and a low-viscosity epoxy resin. Among them, the multifunctional epoxy resin has been specifically described in the previous text and will not be repeated here. The low-viscosity epoxy resin can be an epoxy resin with less than 3 epoxy functional groups and low viscosity. In this embodiment, by adding a low-viscosity epoxy resin to the epoxy resin bottom filling glue, it is beneficial to further improve the fluidity of the epoxy resin bottom filling glue.

[0075] Furthermore, in the epoxy resin bottom filler, the low viscosity epoxy resin: multifunctional epoxy resin is (5-15): (10-20) by weight. In this way, the epoxy resin bottom filler in the present application can have a suitable viscosity and can have a good filling effect on narrow spacing. After curing, the epoxy resin bottom filler has a suitable glass transition temperature, which further meets the performance requirements of the bottom filler in 2.5D / 3D packaging.

[0076] In some embodiments of the present application, the epoxy resin consists of the low-viscosity epoxy resin and the multifunctional epoxy resin.

[0077] Exemplarily, the mass fraction of the low viscosity epoxy resin in the epoxy resin bottom filling glue is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and the range between any two of the above values.

[0078] Exemplarily, the mass fraction of the multifunctional epoxy resin in the epoxy resin bottom filling glue is 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts and the range between any two of the above values.

[0079] Specifically, the viscosity of the low viscosity epoxy resin is 100 mpa.s-3000 mpa.s. Exemplarily, the viscosity of the low viscosity epoxy resin is 100 mpa.s, 200 mpa.s, 300 mpa.s, 400 mpa.s, 500 mpa.s, 600 mpa.s, 700 mpa.s, 800 mpa.s, 900 mpa.s, 1000 mpa.s, 1100 mpa.s, 1200 mpa.s, 1300 mpa.s, 1400 mpa.s, 1500 mpa.s, 1600 mpa.s, 1700 mpa.s, 1800 mpa.s, 1900 mpa.s, 2000 mpa.s, 2100 mpa.s, 2200 mpa.s, 2300 mpa.s, 2400 mpa.s, 2500 mpa.s, 2600 mpa.s, 2700 mpa.s, 2800 mpa.s, 2900 mpa.s, 3000 mpa.s, 3100 mpa.s, 3200 mpa.s, 3300 mpa.s, 3400 mpa.s, 3500 mpa.s, 3600 mpa.s, 3700 mpa.s, 3800 mpa.s, 3900 mpa.s, 4000 mpa.s, 4100 mpa.s, 4200 mpa.s, 4300 mpa.s, 4400 mpa.s, 4500 mpa.s, 4600 mpa.s, 4700 mpa.s, 4800 mpa mpa.s, 1700 mpa.s, 1800 mpa.s, 1900 mpa.s, 2000 mpa.s, 2100 mpa.s, 2200 mpa.s, 2300 mpa.s, 2400 mpa.s, 2500 mpa.s, 2600 mpa.s, 2700 mpa.s, 2800 mpa.s, 2900 mpa.s, 3000 mpa.s and ranges between any two of the above values. It should be noted that, unless otherwise specified, the viscosity in this application refers to the viscosity at room temperature (25°C).

[0080] Specifically, the low-viscosity epoxy resin is selected from one or more combinations of bisphenol A epoxy resin, bisphenol AD ​​epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and hydrogenated bisphenol A epoxy resin.

[0081] In some embodiments of the present application, the epoxy resin is composed of a multifunctional epoxy resin and a low-viscosity epoxy resin, and the curing agent is an aniline curing agent. Calculated by mass, the low-viscosity epoxy resin: the multifunctional epoxy resin: the aniline curing agent: the inorganic filler: the coupling agent is (5-15): (10-20): (10-20): (50-70): (0.1-5). In this way, the epoxy resin bottom filling glue prepared in the embodiment of the present application has lower viscosity and better fluidity, and the cured material has higher bonding strength, better moisture and heat resistance and higher glass transition temperature.

[0082] In some embodiments of the present application, the epoxy resin underfill glue further includes a colorant. Exemplarily, the colorant may be carbon black. It should be noted that the type of colorant does not belong to the main improvement of the present application and is not limited here.

[0083] Furthermore, in the epoxy resin bottom filling glue, the low viscosity epoxy resin: the multifunctional epoxy resin: the aniline curing agent: the inorganic filler: the coupling agent: the colorant is (5-15): (10-20): (10-20): (50-70): (0.1-5): (0.1-5) calculated by mass fraction. The epoxy resin bottom filling glue prepared in the embodiment of the present application has lower viscosity and better fluidity, and the cured material has higher bonding strength, better moisture and heat resistance and higher glass transition temperature.

[0084] Exemplarily, the mass fraction of the colorant in the epoxy resin bottom filling glue is 0.1 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 3 parts, 4 parts, 4.5 parts, 5 parts and the range between any two of the above values.

[0085] The present application also provides a method for preparing an epoxy resin bottom filling adhesive, the method comprising the following steps:

[0086] S10 provides epoxy resin, inorganic filler, curing agent and coupling agent represented by formula (I).

[0087] Specifically, by weight, the epoxy resin: the curing agent: the inorganic filler: the coupling agent is (15-35): (10-20): (50-70): (0.1-5). It should be noted that the epoxy resin, the inorganic filler, the curing agent and the coupling agent have been described in detail above and will not be repeated here.

[0088] S20: mixing the epoxy resin, the inorganic filler and the coupling agent to obtain an epoxy mixture.

[0089] Furthermore, the epoxy resin bottom filling glue also includes a colorant. The epoxy resin includes a low-viscosity epoxy resin and a multifunctional epoxy resin.

[0090] Furthermore, the step of mixing the epoxy resin, the inorganic filler and the coupling agent to obtain a mixture comprises:

[0091] S21: adding epoxy resin, inorganic filler and the coupling agent into a reaction kettle, stirring and mixing to obtain a premix.

[0092] Specifically, a low-viscosity epoxy resin, a multifunctional epoxy resin, an inorganic filler and the coupling agent are added into a reaction kettle, stirred and mixed to obtain a premix.

[0093] S22 then grinds the obtained premix to obtain the epoxy mixture.

[0094] In this way, the coordinated cooperation of the stirring and grinding processes in the reactor is conducive to further improving the dispersibility of the inorganic filler in the epoxy resin.

[0095] Specifically, 5-15 parts of low-viscosity epoxy resin, 10-20 parts of multifunctional epoxy resin, 0.1-5 parts of coupling agent, and 0.1-5 parts of colorant are added to the planetary reactor in sequence. Then, the mixture is mixed evenly at 50-100°C, and then 50-70 parts of inorganic filler are added. The material temperature is controlled to be 70-90°C, and the mixture is stirred at high speed for 50-80 minutes. The obtained material is then subjected to three-roll grinding for three times, with the roller spacing of each grinding being 10-50 μm, so that the inorganic filler is fully and evenly dispersed in the epoxy resin.

[0096] S30: adding a curing agent into the epoxy mixture and mixing to obtain the epoxy resin bottom filling adhesive.

[0097] Specifically, the prepared mixture is first added into a planetary reactor, the material temperature is maintained at 20-40° C., 10-20 parts of a curing agent is then added thereto, vacuum stirred for 50-80 minutes, and finally the material is filtered out by a press to obtain the epoxy resin bottom filling adhesive.

[0098] Example 1

[0099] Preparation of epoxy mixture: 7 parts of low viscosity epoxy resin (bisphenol F epoxy resin, viscosity 1.29 Pa·s, epoxy equivalent: 159), 17 parts of multifunctional epoxy resin (triglycidyl p-aminophenol epoxy resin, viscosity 7.1 Pa·s, epoxy equivalent: 95), 1.5 parts of coupling agent (coupling agent shown in structure (1)), 0.5 parts of colorant (carbon black) are added in sequence in a planetary reactor, and mixed evenly at 80°C. Then, 62 parts of inorganic filler (spherical silica, 500 nm) are added, the material temperature is controlled to 80°C, and high-speed stirring is performed for 60 minutes. Then, the obtained material is subjected to three-roll grinding for 3 times, with the roller spacing of each grinding being 30 μm, so that the inorganic filler is fully dispersed in the epoxy resin to obtain an epoxy mixture.

[0100] Epoxy resin bottom filling glue: First, add the above-mentioned epoxy mixture into a planetary reactor, keep the material temperature at 30°C, then add 12 parts of aniline curing agent (DDM), vacuum stir for 60 minutes, and finally use a press to filter the material and package it to obtain the bottom filling glue (also known as epoxy resin bottom filling glue).

[0101] Example 2

[0102] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (2) replaces the coupling agent shown in structure (1).

[0103] Example 3

[0104] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (3) replaces the coupling agent shown in structure (1).

[0105] Example 4

[0106] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (4) replaces the coupling agent shown in structure (1).

[0107] Example 5

[0108] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (5) replaces the coupling agent shown in structure (1).

[0109] Example 6

[0110] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (6) replaces the coupling agent shown in structure (1).

[0111] Example 7

[0112] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (7) replaces the coupling agent shown in structure (1).

[0113] Example 8

[0114] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (8) replaces the coupling agent shown in structure (1).

[0115] Example 9

[0116] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (1) is used in an amount of 0.5 parts.

[0117] Example 10

[0118] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (1) is used in 1 part.

[0119] Embodiment 11

[0120] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (1) is used in 2 parts.

[0121] Example 12

[0122] The difference between this embodiment and Example 1 is that the coupling agent shown in structure (1) is used in an amount of 2.5 parts.

[0123] Embodiment 13

[0124] The difference between the embodiment 1 and the embodiment 1 is that only one kind of multifunctional epoxy resin (triglycidyl p-aminophenol epoxy resin, viscosity 7.1 Pa·s, epoxy equivalent: 95) is used.

[0125] Embodiment 15

[0126] The difference between this embodiment and Example 1 is that the preparation process only includes high-speed stirring of a planetary reactor.

[0127] Comparative Example 1

[0128] The difference between this embodiment and Example 1 is that (3-glycidylpropoxy)trimethoxysilane is used to replace the coupling agent shown in structure (1).

[0129] Comparative Example 2

[0130] The difference between this embodiment and Example 1 is that no coupling agent is added.

[0131] Experimental testing

[0132] Viscosity test: The viscosity of the freshly prepared sample was measured using a rotational rheometer at room temperature (25°C) and 50 rpm.

[0133] Gel time test: Set the temperature of the heating table to 165℃, drop a drop (weight controlled at 0.5g) of bottom filling glue (also known as epoxy resin bottom filling glue) on a clean glass sheet, and then place the glass sheet on the heating table at 165℃ to heat it. During the heating process, use pointed tweezers to dip the bottom filling glue on the glass sheet several times until the lifted bottom filling glue shows drawing. Stop the test and record it as the gel time of the bottom filling glue.

[0134] Glass transition temperature & storage modulus test: The cured bottom filling glue specimen with a size of 12mm×60mm×3mm was polished smooth and uniform, and its dynamic mechanical analysis was tested in double cantilever mode under a 1Hz sinusoidal strain load - the temperature was increased from room temperature to 270℃ at a heating rate of 5℃ / min, and the maximum values ​​of the storage modulus and loss factor at 30℃ were recorded as the glass transition temperature.

[0135] Bonding strength 260℃: Figure 3 As shown, a shear force test sample of a sandwich structure was prepared, the sample was placed on a 260°C heating table for 5 minutes, and the sample at 260°C was tested using a welding strength tester. Among them, the shear speed was 300μm / s, the shear height was 50μm; the shear force was recorded, and then the bonding strength was calculated using the formula.

[0136] Bond strength - uHAST96 (MPa) - 260℃: The shear force test sample of the sandwich structure was placed in the uHAST aging chamber for 96 hours, and then the aged sample was placed on a 260℃ heating table for 5 minutes, and the sample at 260℃ was tested using a welding strength tester. The shear speed was 300μm / s, and the shear height was 50μm; the shear force was recorded, and then the bond strength was calculated using the formula.

[0137] The performance of the bottom filling glue prepared in this embodiment was tested and compared, and the results are shown in Table 1.

[0138] Table 1

[0139]

[0140]

[0141] The difference between Examples 1 to 8 and Comparative Example 1 is that no coupling agent with the structure of formula (1) is added in Comparative Example 1. It can be seen from the experimental data in Table 1 that the addition of the coupling agent with the structure of formula (1) can effectively increase the gel time, reduce the viscosity of the resin composition, and improve its bonding strength and moisture and heat resistance without almost affecting the glass transition temperature and storage modulus.

[0142] The difference between Example 1 and Example 9 to Example 12 is that the amount of coupling agent of formula (1) added in the epoxy resin bottom filling glue is different. It can be seen from the experimental data in Table 1 that as the amount of coupling agent added to the composition increases, its viscosity tends to gradually decrease, and the bonding strength and moisture and heat resistance tend to increase first and then decrease. When the amount of coupling agent added is about 1.5 parts, its bonding strength and moisture and heat resistance are better.

[0143] Depend on Figures 4 to 6 It can be seen that Figure 4 It can be seen that the sample is a bulk failure. Figure 5 The sample in the middle is mixed failure. Figure 6 The sample in the middle is an interface failure. After adding the coupling agent with the structure of formula (1) to the bottom filling glue, the failure mode of the cured glue changes from interface failure to bulk failure.

[0144] It can be seen from the experimental data in Table 1 that the Tg of the epoxy resin bottom filling glue prepared by the present invention after curing reaches above 175°C, and the viscosity is less than 25Pa·s, the gel time is greater than 520s, the storage modulus is greater than 7.8GPa, and the bonding strength with the silicon substrate is greater than 1.7MPa. Moreover, after the uhast96 wet heat treatment, the bonding strength does not decrease, but increases, and has outstanding moisture and heat resistance.

[0145] The technical solutions provided by the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. An epoxy resin bottom filling adhesive, characterized in that: The epoxy resin bottom filling glue comprises epoxy resin, inorganic filler, curing agent and coupling agent shown in formula (I); Wherein, R is methyl or ethyl, X includes substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic group; R' includes a group capable of reacting with an epoxy system.

2. The epoxy resin bottom filling adhesive according to claim 1, characterized in that: The R' comprises at least one of amino, acryloxy, epoxy, ethoxycarbonyl, methoxy, vinyl, and dioxolane; and / or The X includes substituted or unsubstituted phenyl, substituted or unsubstituted phenoxy, and substituted or unsubstituted C3-C10 cycloalkyl.

3. The epoxy resin bottom filling adhesive according to claim 1 or 2, characterized in that: The coupling agent includes (acryloyloxymethyl)phenylethyltrimethoxysilane, N-[[[2-(trimethoxysilyl)ethyl]phenyl]methyl]-1,2-ethylenediamine, 3-(3-aminophenoxy)propyltrimethoxysilane, m-aminophenyltrimethoxysilane, p-aminophenyltrimethoxysilane, phenacyloxypropyltrimethoxysilane, N-(2-N-benzylaminoethyl)-3-aminopropyltrimethoxysilane, 3,5-dimethoxyphenyltriethoxysilane, 2-(3,4 -Epoxycyclohexyl)ethyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, triethoxy-p-phenylethoxycarbonylsilane, trimethoxy(4-methoxyphenyl)silane, triethoxy(4-methoxyphenyl)silane, trimethoxy[3-(phenylamino)propyl]silane, anilinemethyltriethoxysilane, styrylethyltrimethoxysilane, 4-[2-(trimethoxysilyl)ethyl]phenyl]2-methylacrylate, allylphenylpropyltriethoxysilane, 3-(3-aminophenoxy)propyltrimethoxysilane, phenyltriethoxysilane, 4-triethoxysilylbiphenyl, 3-cyclopentadienylpropyltriethoxysilane, cyclopentanetrimethoxysilane, ethylphenethyltrimethoxysilane, triethoxy-p-phenylethoxycarbonylsilane, 3,4-methylenedioxyphenyltriethoxysilane, 1-naphthyltriethoxysilane, 1-naphthyltrimethoxysilane, 9-phenanthrenyltriethoxysilane, trimethoxy(2-phenylethyl)silane, triethoxy-p-phenylmethylsilane, p-tolyltrimethylsilane, p-(triethoxysilyl)acetophenone, 2-(3-triethoxysilylphenyl)-1,3-dioxolane or a combination thereof.

4. The epoxy resin bottom filling adhesive according to claim 1, characterized in that: In terms of mass fractions, the epoxy resin: the curing agent: the inorganic filler: the coupling agent is (15-35): (10-20): (50-70): (0.1-5).

5. The epoxy resin bottom filling adhesive according to claim 4, characterized in that: The mass fraction of the coupling agent is 0.5 to 2.5 parts; and / or The epoxy resin bottom filling glue also includes a colorant, and the mass fraction of the colorant is 0.1 parts to 5 parts.

6. The epoxy resin underfill as claimed in claim 1, characterized in that: The epoxy resin comprises a multifunctional epoxy resin; and / or The curing agent comprises an aniline curing agent; and / or The inorganic filler includes one or more of aluminum oxide, aluminum nitride, silicon powder, zinc oxide, boron nitride, and diamond; and / or The D50 particle size of the inorganic filler is 50nm-5um.

7. The epoxy resin underfill as claimed in claim 6, characterized in that: The epoxy equivalent of the multifunctional epoxy resin is 90 to 100; and / or The viscosity of the multifunctional epoxy resin is 6.5 Pa·s to 7.3 Pa·s; and / or The multifunctional epoxy resin includes one or more of multifunctional glycidyl ether and glycidyl amine epoxy resins; and / or The aniline curing agent includes one or more of m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, diethyltoluenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane and derivatives thereof; and / or The epoxy resin also includes a low-viscosity epoxy resin, and the viscosity of the low-viscosity epoxy resin is 100 mPa.s-3000 mPa.s.

8. The epoxy resin underfill as claimed in claim 7, characterized in that: The glycidylamine epoxy resin includes one or more of 4.5-epoxycyclohexane-1.2-dicarboxylic acid diglycidyl ester, 4-(2,3-epoxypropoxy)-N,N-di(2,3-epoxypropyl)aniline, N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane, resorcinol formaldehyde tetraglycidyl ether, triglycidyl meta-aminophenol, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; and / or The low viscosity epoxy resin is selected from one or more of bisphenol A epoxy resin, bisphenol AD ​​epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, and hydrogenated bisphenol A epoxy resin; and / or Calculated by weight, the low-viscosity epoxy resin: the multifunctional epoxy resin is (5-15): (10-20).

9. A method for preparing the epoxy resin underfill adhesive according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: Providing epoxy resin, inorganic filler, curing agent and coupling agent represented by formula (I); The epoxy resin, the inorganic filler and the coupling agent are mixed to obtain an epoxy mixture.

10. The preparation method according to claim 9, characterized in that: The step of mixing the epoxy resin, the inorganic filler and the coupling agent to obtain an epoxy mixture comprises: Adding epoxy resin, inorganic filler and the coupling agent into a reaction kettle, stirring and mixing to obtain a premix; The obtained premix is ​​ground to obtain the epoxy mixture.

Images