Low-stress epoxy molding compound as well as preparation method and application thereof

Abstract

The invention discloses a low-stress epoxy molding compound as well as a preparation method and application thereof. The epoxy molding compound is prepared from 6 to 7.5 parts of epoxy resin, 5 to 8 parts of phenolic resin, 65 to 90 parts of inorganic filler, 0.1 to 1.5 parts of curing accelerator, 0.1 to 5 parts of stress absorbent, 0.1 to 1.5 parts of silane coupling agent, 0.1 to 1.5 parts of flame retardant, 0.1 to 1.5 parts of release agent, 0 to 0.5 part of ion trapping agent, 0.01 to 0.5 part of gas-phase silicon and 0 to 0.5 part of coloring agent, wherein the epoxy resin comprises epoxy resin modified by a flexible organic chain segment compound, and the mass of the epoxy resin is 70-80% of the total mass of the epoxy resin. The epoxy molding compound provided by the invention has the advantages of low expansion and low modulus, and effectively improves the reliability problem of the device caused by the stress effect in the packaging process of the electronic device.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy molding compounds, and in particular to a low-stress epoxy molding compound and a preparation method and application thereof. Background Art

[0002] Epoxy Molding Compound (EMC) is a commonly used semiconductor packaging material, typically used to encapsulate and protect chips, wafers, and other microelectronic devices. Epoxy molding compound offers excellent electrical insulation, mechanical properties, and chemical resistance, protecting chips from moisture, corrosion, and mechanical damage. Currently, epoxy molding compound, due to its excellent reliability, cost-effectiveness, simple manufacturing process, and adaptability to large-scale automated production, is widely used in a variety of packaging applications, including semiconductor devices, integrated circuits, consumer electronics, automotive, military, and aviation.

[0003] Epoxy molding compounds typically consist of epoxy resin, phenolic resin, inorganic fillers, curing accelerators, stress absorbers, silane coupling agents, flame retardants, release agents, and colorants. Epoxy resin, as the matrix, offers excellent chemical and mechanical properties, low water absorption, excellent wetting characteristics, good thermal stability, and low cost. However, epoxy resin itself has a large coefficient of thermal expansion (50-100 ppm / °C). This mismatch between the coefficient of thermal expansion (CTE) of the silicon chip (2.5 ppm / °C) and the substrate (4-10 ppm / °C for ceramics and 18-24 ppm / °C for organic FR-4 boards) during wafer-level packaging can lead to warping and cracking of the package, causing serious mechanical reliability issues.

[0004] Currently, the overall thermal expansion coefficient of epoxy molding compounds is typically lowered by adding large amounts (65-90 parts) of inorganic fillers, such as silicon dioxide (thermal expansion coefficient = 0.5 ppm / °C), to achieve a thermal expansion coefficient that matches that of the chip and substrate as closely as possible. When the inorganic filler content reaches 80-85 parts, the thermal expansion coefficient of the epoxy molding compound can reach approximately 15-20 ppm / °C, overcoming the packaging reliability issues caused by the mismatch in thermal expansion coefficients. However, the addition of large amounts of inorganic fillers also brings about a sharp increase in viscosity, a high elastic modulus, and high rigidity, making stress relief through plastic deformation difficult. This leads to the accumulation of thermal and mechanical stresses at the interface of the adhesive materials, as well as damage at the bonding interface. Ultimately, this can easily lead to brittle fracture between the molding compound and the chip under the action of external forces, causing devastating damage to the chip.

[0005] Furthermore, with the development of high-integration electronic chips, chip size is shrinking. This high level of integration is driving increasing package size and complexity, placing higher demands on epoxy molding compounds. These include: excellent spiral flow length to ensure processability, a lower thermal expansion coefficient to prevent device warping and delamination, and a lower modulus to ensure higher toughness (ensuring excellent mechanical properties). However, the inorganic filler content in the molding compound must reach 65-90 parts per million, significantly increasing the overall molding compound modulus. Summary of the Invention

[0006] To address the above-mentioned technical issues, the present invention provides a low-stress epoxy molding compound, its preparation method, and its application. To simultaneously address the conflicting issues of low expansion and low modulus in epoxy molding compounds, the present invention uses an epoxy resin modified with flexible polymer segments as a matrix to produce a low-stress, low-shrinkage epoxy molding compound, effectively improving device reliability issues caused by stress during electronic device packaging.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] In one aspect, the present invention provides a modified epoxy resin, wherein the modified epoxy resin is an epoxy resin modified with a flexible organic segment, and the modification comprises the following steps:

[0009] reacting an epoxy resin and a flexible organic chain segment compound in a solvent to obtain the modified epoxy resin;

[0010] The flexible organic chain segment compound is a compound having active groups at both ends; the active groups are selected from one or more of hydroxyl, carboxyl and amino groups.

[0011] As a preferred embodiment, the epoxy resin is a polyaromatic epoxy resin, selected from one or more aromatic epoxy resins such as o-cresol novolac epoxy resin, phenol biphenyl novolac epoxy resin, biphenyl liquid crystal epoxy resin, o-cresol novolac epoxy resin and 1,5-diepoxynaphthalene resin;

[0012] Preferably, the flexible organic chain segment compound is selected from one or more aromatic polyols such as double-terminated hydroxypropyl polymethylsiloxane, double-terminated aminopropyl polymethylsiloxane, hydroxy-terminated polybutadiene, sebacic acid, suberic acid, adipic acid, decanediol, Z-type perfluoropolyether tetraol and polycarbonate diol;

[0013] In certain specific embodiments, the dual-terminal hydroxypropyl polymethylsiloxane has a structural formula as shown in Formula I, and has a weight-average molecular weight of 500 to 10,000;

[0014]

[0015] In certain specific embodiments, the double-terminated aminopropyl polymethylsiloxane has a structural formula as shown in Formula II, and its weight average molecular weight is 500 to 10,000;

[0016]

[0017] In certain specific embodiments, the hydroxyl-terminated polybutadiene has a structural formula as shown in Formula III, and its weight average molecular weight is 500 to 10,000;

[0018]

[0019] In certain specific embodiments, the Z-type perfluoropolyether tetraol has a structural formula as shown in Formula IV, and has a weight average molecular weight of 500 to 10,000;

[0020]

[0021] Preferably, the solvent is selected from one or more of dichloromethane, chloroform, acetone, toluene, carbon tetrachloride and diethyl ether;

[0022] In certain specific embodiments, the reaction is carried out under the action of a catalyst; preferably, the catalyst is selected from (boron trifluoride etherate complex), and one or more of Mg(HSO4)2.

[0023] As a preferred embodiment, the mass ratio of the epoxy resin to the flexible organic chain segment compound is (5-20): (2-10);

[0024] Preferably, the amount of the solvent and the epoxy resin is such that 5 to 20 g of epoxy resin corresponds to every 100 to 300 mL of solvent;

[0025] Preferably, the amount of the catalyst and the epoxy resin is such that every 0.05 to 0.5 g of catalyst corresponds to 5 to 20 g of epoxy resin.

[0026] As a preferred embodiment, the reaction is carried out at 20-30°C;

[0027] Preferably, the reaction time is 5 to 15 hours;

[0028] In certain specific embodiments, the reaction is specifically carried out by stirring the epoxy resin and the flexible organic segment compound in a solvent for 5 to 30 minutes to dissolve them in an ice-water bath at -5°C to 5°C; slowly adding the catalyst dropwise and reacting at room temperature for 5 to 15 hours; and then adding a saturated sodium bicarbonate solution to quench the reaction;

[0029] In some specific embodiments, the reaction further includes post-treatment; the post-treatment includes washing, extraction, drying, removing organic solvents at room temperature and drying at room temperature; the operation of removing organic solvents at room temperature is rotary evaporation; the drying at room temperature is drying at 20-30°C.

[0030] In the technical solution of the present invention, the double-end active groups of the flexible organic chain segment compound are reactive with the epoxy groups of the epoxy resin, and a modified epoxy resin having a "hard segment-soft segment-hard segment" structure can be obtained during the modification process, wherein the hard segment is the chain structure of the epoxy resin itself, and the soft segment is the structural unit of the flexible organic chain segment compound.

[0031] On the other hand, the present invention provides a low-stress epoxy molding compound, which includes, by mass: 6 to 7.5 parts of epoxy resin, 5 to 8 parts of phenolic resin, 65 to 90 parts of inorganic filler, 0.1 to 1.5 parts of curing accelerator, 0.1 to 5 parts of stress absorber, 0.1 to 1.5 parts of silane coupling agent, 0.1 to 1.5 parts of flame retardant, 0.1 to 1.5 parts of release agent, 0 to 0.5 parts of ion capture agent, 0.01 to 0.5 parts of fumed silicon and 0 to 0.5 parts of colorant; wherein the epoxy resin includes epoxy resin I and epoxy resin II, the epoxy resin II is the above-mentioned modified epoxy resin; the mass of the epoxy resin II is 70% to 80% of the total mass of the epoxy resin.

[0032] In the technical solution of the present invention, the epoxy resin I is an epoxy resin that has not been modified with a flexible organic chain segment relative to the epoxy resin II. Its type is not particularly limited, and specific examples include biphenyl liquid crystal epoxy resin, dicyclopentadiene phenol epoxy resin, 1,5-diepoxynaphthalene resin, naphthalene ring-containing epoxy resin, phenol·aralkyl resin, naphthol·aralkyl resin, etc., epoxides of aralkyl-type phenol resins, trimethylolpropane-type epoxy resins, and ester ring epoxy resins. The above-mentioned epoxy resins can be used alone or in any combination.

[0033] As a preferred embodiment, the phenolic resin is selected from one or more of phenol novolac resin, cresol novolac epoxy resin, biphenyl novolac resin, triphenylmethane novolac resin, naphthol novolac resin, aralkyl aldehyde resin and biphenyl novolac resin;

[0034] Preferably, the inorganic filler is modified silica or unmodified silica; the silica is preferably fused crystallized spherical silica; the particle size of the inorganic filler is 1 to 75 μm;

[0035] Preferably, the modifying agent is selected from one or more silane compounds such as alkoxysilane compounds having one or more of primary amino groups, secondary amino groups and tertiary amino groups, alkoxysilane compounds having epoxy groups, alkoxysilane compounds having mercapto groups, alkoxysilane compounds having alkyl groups, alkoxysilane compounds having urea groups and alkoxysilane compounds having vinyl groups; among them, alkoxysilane compounds having epoxy groups are preferred from the perspective of compatibility;

[0036] In the technical solution of the present invention, the type of the curing accelerator is not particularly limited, and specific examples include cyclic amidine compounds such as 1,8-diaza-bicyclo[5.4.0]undecene-7, 1,5-diaza-bicyclo[4.3.0]nonene, and 5,6-dibutylamino-1,8-diaza-bicyclo[5.4.0]undecene-7, and quinone compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-toluoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1, 2-methylimidazoline, 2-phenyl Imidazolinyl, 2-phenyl-4-methylimidazoline and other imidazolines and their derivatives, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tri(4-methylphenyl)phosphine, diphenylphosphine, phenylphosphine, and the like, and compounds with intramolecular polarity obtained by adding maleic anhydride, the above-mentioned quinone compounds, phenylazomethane, phenol resin and other compounds having π bonds to these phosphines; the above-mentioned compounds can be used alone or in any combination; preferably, the curing accelerator is selected from one or more of tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tri(4-methylphenyl)phosphine, diphenylphosphine and phenylphosphine;

[0037] In the technical solution of the present invention, the stress absorber is a styrene-butadiene copolymer and its derivatives, selected from one or more of acrylonitrile-butadiene-styrene copolymer, epoxy-terminated styrene-butadiene-styrene block copolymer, epoxidized styrene-butadiene-styrene block copolymer, styrene-butadiene rubber, carboxyl-terminated liquid acrylonitrile-butadiene rubber (CTBN) and hydroxyl-terminated liquid acrylonitrile-butadiene rubber (HTBN), preferably one or more of epoxy-terminated styrene-butadiene-styrene block copolymer and styrene-butadiene rubber;

[0038] In the technical solution of the present invention, the type of the silane coupling agent is not particularly limited, and specific examples include γ-(2,3-epoxypropoxy)propyltrimethoxysilane, trimethyloxyphenylsilane, 3-aminopropyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, (3-aminopropyl)triethoxysilane, 3-aminopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, γ-anilinopropyl Methyldimethoxysilane, γ-anilinopropylmethyldiethoxysilane, γ-anilinopropylethyldiethoxysilane, γ-anilinopropylethyldimethoxysilane, γ-anilinomethyltrimethoxysilane, γ-anilinomethyltriethoxysilane, γ-anilinomethyldimethoxysilane, γ-anilinomethyldiethoxysilane, γ-anilinomethylethyldiethoxysilane and γ-anilinomethylethyldimethoxysilane, etc.; the above-mentioned can be used alone or in any combination;

[0039] In the technical solution of the present invention, the type of the flame retardant is not particularly limited, and specific examples include inorganic flame retardants (such as hydrated metal compounds such as aluminum hydroxide), halogen flame retardants, phosphorus flame retardants, and organic metal salt flame retardants (phosphorus-halogen flame retardants).

[0040] In the technical solution of the present invention, the release agent is selected from one or more of oxidized or non-oxidized polyethylene wax, carnauba wax, stearic acid and synthetic paraffin wax, preferably one or more of carnauba wax and synthetic paraffin wax;

[0041] In the technical solution of the present invention, the ion capture agent is selected from one or more of a cation capture agent, anion capture agent and anion-cation capture agent;

[0042] In the technical solution of the present invention, the fumed silicon is fumed silicon dioxide commonly used in epoxy resin compositions for encapsulation, without any particular limitation, and its particle size is preferably 5 to 40 nm.

[0043] In another aspect, the present invention provides a method for preparing the above-mentioned epoxy molding compound, comprising the following steps:

[0044] Stirring and mixing the components uniformly according to a certain proportion, and then extruding and molding to obtain the epoxy molding compound;

[0045] Preferably, the extrusion temperature is 80-130°C.

[0046] In certain specific embodiments, the preparation method specifically comprises the following steps:

[0047] (1) Stirring the modified epoxy resin, stress absorber, flame retardant, release agent, and ion scavenger at 0-10° C. and 200-800 rpm for 5-10 minutes to mix uniformly;

[0048] (2) Add inorganic filler, fumed silica, and colorant, and continue stirring at 0-10°C and 200-800 rpm for 8-15 minutes;

[0049] (3) Add phenolic resin and curing accelerator, and continue stirring at 0-10°C and 200-800 rpm for 3-5 minutes;

[0050] (4) adding a silane coupling agent at 50-300 rpm, and continuing to stir at 0-10° C. and 200-800 rpm for 10-30 min to obtain a mixed slurry;

[0051] (5) Extruding through a twin-screw extrusion process, cooling and crushing, and then pre-pressing and molding to obtain the epoxy molding compound.

[0052] In another aspect, the present invention provides applications of the modified epoxy resin, the epoxy molding compound, and the preparation method in semiconductor packaging.

[0053] The above technical solution has the following advantages or beneficial effects:

[0054] The present invention provides a low-stress epoxy molding compound and its preparation method and application. The present invention reacts a polyaromatic resin and a flexible organic chain segment compound under the action of a catalyst to obtain an epoxy resin modified with a long-chain flexible chain segment. The modified epoxy resin has a "hard segment-soft segment-hard segment" structure. When it is used as the matrix resin of the epoxy molding compound, it can produce cross-linking with a curing agent, thereby effectively reducing the cross-linking density and facilitating molecular movement. Among them, the flexible organic chain segment can be bonded to the dense epoxy resin cross-linked network, and the curing shrinkage process can produce microphase separation, forming a dense and loose two-phase network structure, ultimately enabling the epoxy molding compound to achieve the effect of reducing stress and shrinkage characteristics. In addition, the flexible organic chain segment can effectively reduce the cross-linking density so that the modulus of the overall molding compound is reduced to maintain low stress, which enables the epoxy molding compound to significantly improve toughness, can greatly reduce the internal stress and thermal expansion coefficient of the epoxy molding material, and has better processing performance and process reliability. In addition, the modified epoxy resin can synergistically interact with the stress absorber through the embedded flexible organic chain segments, thereby alleviating the stress problem caused by the high modulus of the epoxy molding compound after curing and improving the mechanical reliability of the molding compound. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a diagram of the segment structure of the modified epoxy resin A-1 obtained in Preparation Example 1 of the present invention.

[0056] Figure 2 This is a segment structure diagram of the modified epoxy resin A-5 obtained in Preparation Example 5 of the present invention. DETAILED DESCRIPTION

[0057] On one hand, the present invention provides a modified epoxy resin, which is an epoxy resin modified with a flexible organic chain segment. The modification comprises the following steps: in a solvent, an epoxy resin and a flexible organic chain segment compound are reacted under the action of a catalyst to obtain the modified epoxy resin; wherein the flexible organic chain segment compound is a compound having active groups at both ends; the active groups are selected from one or more of hydroxyl, carboxyl and amino groups.

[0058] In the preferred technical solution of the present invention, the epoxy resin is a polyaromatic epoxy resin, specifically polyaromatic epoxy resins such as o-cresol novolac epoxy resin, phenol biphenyl novolac epoxy resin, biphenyl type liquid crystal epoxy resin, o-cresol novolac epoxy resin and 1,5-diepoxynaphthalene resin.

[0059] In the preferred technical solution of the present invention, the flexible organic chain segment compound is selected from one or more aromatic polyols such as double-terminal hydroxypropyl polymethylsiloxane, double-terminal aminopropyl polymethylsiloxane, terminal hydroxy polybutadiene, sebacic acid, suberic acid, adipic acid, decanediol, Z-type perfluoropolyether tetraol and polycarbonate diol.

[0060] In the preferred technical solution of the present invention, the double-terminal hydroxypropyl polymethylsiloxane has a structural formula as shown in Formula I, and its weight average molecular weight is 500 to 10,000;

[0061]

[0062] In the preferred technical solution of the present invention, the double-terminal aminopropyl polymethylsiloxane has a structural formula as shown in Formula II, and its weight average molecular weight is 500 to 10,000;

[0063]

[0064] In the preferred technical solution of the present invention, the hydroxy-terminated polybutadiene has a structural formula as shown in Formula III, and its weight average molecular weight is 500 to 10,000;

[0065]

[0066] In the preferred technical solution of the present invention, the Z-type perfluoropolyether tetraol has a structural formula as shown in Formula IV, and its weight average molecular weight is 500 to 10,000;

[0067]

[0068] In a preferred technical solution of the present invention, the solvent is selected from one or more of dichloromethane, chloroform, acetone, toluene, carbon tetrachloride and ether.

[0069] In certain specific embodiments, the reaction is carried out under the action of a catalyst; the catalyst is selected from (boron trifluoride etherate complex), and one or more of Mg(HSO4)2.

[0070] In a preferred technical solution of the present invention, the mass ratio of the epoxy resin to the flexible organic chain segment compound is (5-20):(2-10).

[0071] In a preferred technical solution of the present invention, the usage ratio of the solvent and the epoxy resin is 5 to 20 g of epoxy resin per 100 to 300 mL of solvent.

[0072] In a preferred technical solution of the present invention, the amount of the catalyst and the epoxy resin is such that every 0.05 to 0.5 g of catalyst corresponds to 5 to 20 g of epoxy resin.

[0073] In a preferred technical solution of the present invention, the reaction is carried out at 20-30° C. and the reaction time is 5-15 h.

[0074] In certain specific embodiments, the reaction is carried out by stirring the epoxy resin and the flexible organic segment compound in a solvent for 5 to 30 minutes to dissolve them in an ice-water bath at -5°C to 5°C; slowly adding the catalyst dropwise and reacting at room temperature for 5 to 15 hours; and then adding a saturated sodium bicarbonate solution to quench the reaction.

[0075] In certain specific embodiments, the reaction further includes post-treatment, which includes washing, extraction, drying, removing the organic solvent at room temperature and drying at room temperature; wherein the operation of removing the organic solvent at room temperature is rotary evaporation; and drying at room temperature is drying at 20-30°C.

[0076] On the other hand, the present invention provides a low-stress epoxy molding compound, which includes, by mass: 6 to 7.5 parts of epoxy resin, 5 to 8 parts of phenolic resin, 65 to 90 parts of inorganic filler, 0.1 to 1.5 parts of curing accelerator, 0.1 to 5 parts of stress absorber, 0.1 to 1.5 parts of silane coupling agent, 0.1 to 1.5 parts of flame retardant, 0.1 to 1.5 parts of release agent, 0 to 0.5 parts of ion capture agent, 0.01 to 0.5 parts of fumed silicon and 0 to 0.5 parts of colorant; wherein the epoxy resin includes epoxy resin I and epoxy resin II, epoxy resin II is the above-mentioned modified epoxy resin, and its mass accounts for 70% to 80% of the total mass of the epoxy resin.

[0077] In the technical solution of the present invention, epoxy resin I is an epoxy resin that has not been modified with a flexible organic chain segment relative to epoxy resin II. Its type is not particularly limited, and specific examples include biphenyl liquid crystal epoxy resin, dicyclopentadiene phenol epoxy resin, 1,5-diepoxynaphthalene resin, naphthalene ring-containing epoxy resin, phenol·aralkyl resin, naphthol·aralkyl resin, etc., epoxides of aralkyl-type phenol resins, trimethylolpropane-type epoxy resins, and ester ring epoxy resins. The above-mentioned ones can be used alone or in any combination.

[0078] In a preferred technical solution of the present invention, the phenolic resin is selected from one or more of phenol novolac resin, cresol novolac epoxy resin, biphenyl novolac resin, triphenylmethane novolac resin, naphthol novolac resin, aralkyl aldehyde resin and biphenyl novolac resin.

[0079] In a preferred technical solution of the present invention, the inorganic filler is modified silica or unmodified silica; wherein the silica is preferably fused crystallized spherical silica with a particle size of 1 to 75 μm.

[0080] In a preferred technical solution of the present invention, the modifier for modified silica is selected from one or more silane compounds such as alkoxysilane compounds having one or more of primary amino groups, secondary amino groups and tertiary amino groups, alkoxysilane compounds having epoxy groups, alkoxysilane compounds having mercapto groups, alkoxysilane compounds having alkyl groups, alkoxysilane compounds having urea groups and alkoxysilane compounds having vinyl groups; among them, from the perspective of compatibility, alkoxysilane compounds having epoxy groups are preferred.

[0081] In the technical solution of the present invention, the type of curing accelerator is not particularly limited, and specific examples include cyclic amidine compounds such as 1,8-diaza-bicyclo[5.4.0]undecene-7, 1,5-diaza-bicyclo[4.3.0]nonene, and 5,6-dibutylamino-1,8-diaza-bicyclo[5.4.0]undecene-7, and quinone compounds such as maleic anhydride, 1,4-benzoquinone, 2,5-toluoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,2-methylimidazoline, Imidazolinoids such as 2-phenylimidazoline and 2-phenyl-4-methylimidazoline and their derivatives, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tri(4-methylphenyl)phosphine, diphenylphosphine, and phenylphosphine, and compounds with intramolecular polarity obtained by adding maleic anhydride, the above-mentioned quinone compounds, phenylazomethane, phenol resin, and other compounds having π bonds to these phosphines; the above-mentioned compounds may be used alone or in any combination; preferably, one or more of tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tri(4-methylphenyl)phosphine, diphenylphosphine, and phenylphosphine are used.

[0082] In a preferred technical solution of the present invention, the stress absorber is a styrene-butadiene copolymer and its derivatives, selected from one or more of acrylonitrile-butadiene-styrene copolymer, epoxy-terminated styrene-butadiene-styrene block copolymer, epoxidized styrene-butadiene-styrene block copolymer, styrene-butadiene rubber, carboxyl-terminated liquid acrylonitrile-butadiene rubber (CTBN) and hydroxyl-terminated liquid acrylonitrile-butadiene rubber (HTBN), preferably one or more of epoxy-terminated styrene-butadiene-styrene block copolymer and styrene-butadiene rubber.

[0083] In the technical solution of the present invention, the type of silane coupling agent is not particularly limited, and specific examples include γ-(2,3-epoxypropoxy)propyltrimethoxysilane, trimethyloxyphenylsilane, 3-aminopropyltriethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, (3-aminopropyl)triethoxysilane, 3-aminopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, γ-anilinopropylmethyl γ-anilinopropylmethyldiethoxysilane, γ-anilinopropylethyldiethoxysilane, γ-anilinopropylethyldimethoxysilane, γ-anilinomethyltrimethoxysilane, γ-anilinomethyltriethoxysilane, γ-anilinomethyldimethoxysilane, γ-anilinomethyldiethoxysilane, γ-anilinomethylethyldiethoxysilane and γ-anilinomethylethyldimethoxysilane; the above-mentioned can be used alone or in any combination.

[0084] In the technical solution of the present invention, the type of flame retardant is not particularly limited, and specific examples include inorganic flame retardants (such as hydrated metal compounds such as aluminum hydroxide), halogen flame retardants, phosphorus flame retardants, organic metal salt flame retardants (phosphorus-halogen flame retardants), etc.

[0085] In a preferred technical solution of the present invention, the release agent is selected from one or more of oxidized or non-oxidized polyethylene wax, carnauba wax, stearic acid and synthetic paraffin wax, preferably one or more of carnauba wax and synthetic paraffin wax.

[0086] In a preferred technical solution of the present invention, the ion capture agent is selected from one or more of a cation capture agent, anion capture agent and anion-cation capture agent.

[0087] In the technical solution of the present invention, the fumed silicon is the fumed silicon dioxide commonly used in epoxy resin compositions for encapsulation, and is not particularly limited. The particle size thereof is preferably 5 to 40 nm.

[0088] In another aspect, the present invention provides a method for preparing the above-mentioned epoxy molding compound, comprising the following steps:

[0089] The components are stirred and mixed uniformly according to a certain proportion, and then extruded to form the mixture; wherein the extrusion temperature is preferably 80-130°C.

[0090] In certain specific embodiments, the preparation method specifically comprises the following steps:

[0091] (1) Stirring the modified epoxy resin, stress absorber, flame retardant, release agent, and ion scavenger at 0-10° C. and 200-800 rpm for 5-10 minutes to mix uniformly;

[0092] (2) Add inorganic filler, fumed silica, and colorant, and continue stirring at 0-10°C and 200-800 rpm for 8-15 minutes;

[0093] (3) Add phenolic resin and curing accelerator, and continue stirring at 0-10°C and 200-800 rpm for 3-5 minutes;

[0094] (4) adding a silane coupling agent at 50-300 rpm, and continuing to stir at 0-10° C. and 200-800 rpm for 10-30 min to obtain a mixed slurry;

[0095] (5) Extruded by twin-screw extrusion process, cooled and crushed, and then pre-pressed into shape.

[0096] In another aspect, the present invention provides applications of the modified epoxy resin, the epoxy molding compound, and the preparation method in semiconductor packaging.

[0097] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the technical solutions of the present invention are described in detail below through specific embodiments. However, these embodiments should not be construed as limiting the scope of the present invention. In the present invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art.

[0098] In the following:

[0099] Epoxy resin a01: o-cresol novolac epoxy resin, epoxy equivalent weight is 187;

[0100] Epoxy resin a02: phenol biphenyl novolac epoxy resin purchased from Kayaku NC3000, with an epoxy equivalent weight of 260;

[0101] Epoxy resin a03: biphenyl liquid crystal epoxy resin purchased from Mitsubishi chemical YX4000, with an epoxy equivalent weight of 187;

[0102] The room temperature is 20-30℃.

[0103] Production Example 1:

[0104] This manufacturing example provides a modified epoxy resin A-1, which is an o-cresol novolac epoxy resin modified with double-terminal hydroxypropyl polymethylsiloxane, with an epoxy equivalent weight of 331. The preparation process is as follows:

[0105] Step 1: Under anhydrous conditions, add 15 g of o-cresol novolac epoxy resin (epoxy resin a01) and 5 g of double-terminated hydroxypropyl polymethylsiloxane (Formula 1) to 200 mL of dichloromethane;

[0106] Step 2: Stir in a 0°C water bath for 30 min, slowly add 1 mL (1.15 g) of boron trifluoride ether complex, and react at room temperature for 15 h.

[0107] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-1.

[0108] Weight average molecular weight = 1000 Formula 1

[0109] The segment structure of the modified epoxy resin A-1 obtained in this preparation example is as follows Figure 1 As shown, it has a "hard segment-soft segment-hard segment" structure.

[0110] Production Example 2:

[0111] This manufacturing example provides a modified epoxy resin A-2, which is an o-cresol novolac epoxy resin modified with double-terminal aminopropyl polymethylsiloxane, with an epoxy equivalent weight of 320. The preparation process is as follows:

[0112] Step 1: In anhydrous conditions, add 15 g of o-cresol novolac epoxy resin (epoxy resin a01) and 5 g of double-terminated aminopropyl polymethylsiloxane (Formula 2) to 200 mL of dichloromethane;

[0113] Step 2: Stir in a 0℃ water bath for 30 min, slowly add 1 mL of boron trifluoride ether complex, and react at room temperature for 15 h.

[0114] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-2.

[0115] Weight average molecular weight = 1000, formula 2

[0116] Production Example 3:

[0117] This manufacturing example provides a modified epoxy resin A-3, which is an o-cresol novolac epoxy resin modified with terminal hydroxyl polybutadiene, with an epoxy equivalent weight of 335. The preparation process is as follows:

[0118] Step 1: Under anhydrous conditions, add 15 g of o-cresol novolac epoxy resin (epoxy resin a01) and 5 g of hydroxy-terminated polybutadiene (Formula 3) to 200 mL of dichloromethane;

[0119] Step 2: Stir in a 0℃ water bath for 30 min, slowly add 1 mL of boron trifluoride ether complex, and react at room temperature for 15 h.

[0120] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-3.

[0121] Weight average molecular weight = 1000, formula 3

[0122] Production Example 4:

[0123] This preparation example provides a modified epoxy resin A-4, which is an o-cresol novolac epoxy resin modified with a Z-type perfluoropolyether tetraol, and has an epoxy equivalent weight of 335. The preparation process is as follows:

[0124] Step 1: Under anhydrous conditions, 15 g of o-cresol novolac epoxy resin (epoxy resin a01) and 5 g of Z-type perfluoropolyether tetraol (Formula 4) were added to 200 mL of dichloromethane;

[0125] Step 2: Stir in a 0℃ water bath for 30 min, slowly add 1 mL of boron trifluoride ether complex, and react at room temperature for 15 h.

[0126] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-4.

[0127]

[0128] Weight average molecular weight = 1000, formula 4

[0129] Production Example 5:

[0130] This preparation example provides a modified epoxy resin A-5, which is a phenol-biphenyl novolac epoxy resin modified with double-terminal hydroxypropyl polymethylsiloxane, with an epoxy equivalent weight of 312. The preparation process is as follows:

[0131] Step 1: Under anhydrous conditions, add 20 g of phenol biphenyl novolac epoxy resin (epoxy resin a02) and 5 g of double-terminal hydroxypropyl polymethylsiloxane (Formula 1) to 200 mL of dichloromethane;

[0132] Step 2: Stir in a 0℃ water bath for 30 min, slowly add 1 mL of boron trifluoride ether complex, and react at room temperature for 15 h.

[0133] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-5.

[0134] Weight average molecular weight = 1000, formula 1

[0135] The segment structure of the modified epoxy resin obtained in this manufacturing example is as follows Figure 2 As shown, it has a "hard segment-soft segment-hard segment" structure.

[0136] Production Example 6:

[0137] This preparation example provides a modified epoxy resin A-6, which is a phenol-biphenyl novolac epoxy resin modified with double-terminal aminopropyl polymethylsiloxane, with an epoxy equivalent weight of 290. The preparation process is as follows:

[0138] Step 1: Under anhydrous conditions, add 20 g of phenol biphenyl novolac epoxy resin (epoxy resin a02) and 5 g of double-terminated aminopropyl polymethylsiloxane (Formula 2) to 200 mL of dichloromethane;

[0139] Step 2: Stir in a 0℃ water bath for 30 min, slowly add 1 mL of boron trifluoride ether complex, and react at room temperature for 15 h.

[0140] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-6.

[0141] Weight average molecular weight = 1000 Formula 2

[0142] Production Example 7:

[0143] This manufacturing example provides a modified epoxy resin A-7, which is a phenol-biphenyl novolac epoxy resin modified with terminal hydroxyl polybutadiene, with an epoxy equivalent weight of 317. The preparation process is as follows:

[0144] Step 1: Under anhydrous conditions, add 20 g of phenol biphenyl novolac epoxy resin (epoxy resin a02) and 5 g of hydroxyl-terminated polybutadiene (Formula 3) to 200 mL of dichloromethane;

[0145] Step 2: Stir in a 0℃ water bath for 30 min, slowly add 1 mL of boron trifluoride ether complex, and react at room temperature for 15 h.

[0146] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-7.

[0147] Weight average molecular weight = 1000, formula 3

[0148] Production Example 8:

[0149] This preparation example provides a modified epoxy resin A-8, which is a phenol-biphenyl novolac epoxy resin modified with a Z-type perfluoropolyether tetraol, and has an epoxy equivalent weight of 312. The preparation process is as follows:

[0150] Step 1: Under anhydrous conditions, add 20 g of phenol biphenyl novolac epoxy resin (epoxy resin a02) and 5 g of Z-type perfluoropolyether tetraol (Formula 4) to 200 mL of dichloromethane;

[0151] Step 2: Stir in a 0℃ water bath for 30 min, slowly add 1 mL of boron trifluoride ether complex, and react at room temperature for 15 h.

[0152] Step 3: After the reaction is completed, saturated sodium bicarbonate aqueous solution is added to quench the reaction, and the mixture is washed with distilled water until neutral. The organic phase is separated and extracted, and the organic solvent is removed by rotary evaporation at room temperature after drying over anhydrous magnesium sulfate, and vacuum drying at 25°C to obtain modified epoxy resin A-8.

[0153]

[0154] Weight average molecular weight = 1000, formula 4

[0155] Examples 1-8

[0156] This embodiment provides an epoxy molding compound, as shown in Table 1-2, which includes the following components:

[0157] (a) Epoxy resin;

[0158] (b) Curing agent: phenolic resin;

[0159] (c) Inorganic filler: Silica filler (maximum cutoff particle size: 53 μm) surface-treated with an epoxy silane coupling agent. The modification process is as follows: 500 parts by mass of silicon oxide and 100 parts by mass of 3-glycidyloxypropyltrimethoxysilane are poured into a three-necked flask, heated in an oil bath at 150°C, and stirred for 15 hours. The filler is then washed with anhydrous ethanol and dried in a drying oven at 80°C to obtain a modified silica filler.

[0160] (d) curing accelerator: triphenylphosphine;

[0161] (e) Stress absorber: carboxyl-terminated liquid nitrile rubber (CTBN);

[0162] (f) Silane coupling agent: γ-glycidyloxypropyltrimethoxysilane;

[0163] (g) Flame retardant: trimethyl phosphate;

[0164] (h) Release agent: carnauba wax;

[0165] (j) Fumed silicon: nano-silicon dioxide, with an average particle size of 5 to 40 nm and a specific surface area of ​​300 ± 30 m 2 / g;

[0166] (k) Colorant: carbon black;

[0167] Comparative Example 1-2

[0168] This comparative example provides an epoxy molding compound, as shown in Table 1-2, comprising the following components:

[0169] (a) Epoxy resin

[0170] (b) Curing agent: phenolic resin Meiwa chemical MEH7800;

[0171] (c) Inorganic filler: silica filler (maximum cut-off particle size: 53 μm) surface-treated with an epoxy silane coupling agent, the modification process being the same as in Example 1-8;

[0172] (d) curing accelerator: triphenylphosphine;

[0173] (e) Stress absorber: carboxyl-terminated liquid nitrile rubber (CTBN);

[0174] (f) Silane coupling agent: γ-glycidyloxypropyltrimethoxysilane;

[0175] (g) Flame retardant: trimethyl phosphate;

[0176] (h) Release agent: carnauba wax;

[0177] (j) Fumed silicon: nano-silicon dioxide, with an average particle size of 5 to 40 nm and a specific surface area of ​​300 ± 30 m 2 / g;

[0178] (k) Colorant: carbon black;

[0179] The preparation process of the above-mentioned epoxy molding compound is as follows:

[0180] Step 1: Pour (a) epoxy resin and (e) stress absorber, (g) flame retardant, and (h) release agent into a low-temperature (8°C) high-speed mixer and stir at 600 rpm for 8 minutes to mix evenly; then add (c) inorganic filler, (j) fumed silica, and (j) colorant into the low-temperature high-speed mixer and stir at 800 rpm for 12 minutes; finally, add (b) phenolic resin and (d) curing accelerator into the low-temperature high-speed mixer and stir at 800 rpm for 5 minutes, then reduce the speed of the high-speed mixer to 260 rpm and uniformly add (f) silane coupling agent; after completion, stir again at 800 rpm for 25 minutes to mix the whole.

[0181] Step 2: Extruded through an A60 twin-screw extruder at 115°C, cooled and crushed in a cooling belt, and then pre-pressed into shape to obtain a low-stress and low-shrinkage epoxy molding compound.

[0182] The prepared epoxy molding compound was used as an evaluation sample to perform the following performance evaluation. The results are shown in Table 1-2.

[0183] Test items:

[0184] Viscosity test: The viscosity was measured using a Shimadzu capillary rheometer at 175°C with a load of 10 kgf. The viscosity unit is Pa.s.

[0185] Thermal expansion coefficient test: A thermal mechanical analyzer (TMA, Netzsch Instrument model: TMA402F1) was used to test the sample. The sample was heated from room temperature to about 300° C. at a heating rate of 5° C. / min.

[0186] Storage modulus test: A dynamic mechanical analyzer (DMA, TA Instrument model Q80) was used for testing under a 1 Hz sinusoidal strain load and a three-point bending mode.

[0187] Spiral Flow: The epoxy resin composition was transferred molded using a spiral flow measurement mold according to EMMI-1-66 under the structural conditions of a mold temperature of 175°C, a molding pressure of 6.9 MPa, and a curing time of 120 s to determine the flow distance (cm).

[0188] Gel time: Place the epoxy resin composition on a curing plate heated to 175°C, use a stopwatch to time, and use the front end of a spatula to evenly stir the sample. Stop the timer when the sample gels. This time is the gel time.

[0189] Adhesion strength test: The pudding structure test specimens were tested on FR4 substrate before and after PMC and wet heat treatment. The Dage adhesion test equipment was used to test the adhesion strength.

[0190]

Table 1

[0191]

[0192]

[0193]

Table 2

[0194]

[0195]

[0196] It can be seen from the above comparative examples and embodiments that the epoxy molding material provided by the present invention adopts an epoxy resin having a "hard segment-soft segment-hard segment" structure ring as the base resin. It can be seen that after the epoxy resin modified with this flexible organic chain segment is introduced into the epoxy molding material, the thermal expansion coefficient of the epoxy molding material before and after the glass transition temperature can be significantly reduced, and the storage modulus at low and normal temperatures can be effectively reduced. Examples 5, 6, and 8 can effectively reduce the viscosity of the epoxy molding material, while maintaining a good bonding strength with the FR4 substrate at room temperature and high temperature. After wet heat treatment, its bonding strength does not decrease significantly. In addition, different types of flexible forging are introduced into the rigid epoxy resin modified to obtain an epoxy resin having a "hard segment-soft segment-hard segment" structure ring and introduced into the epoxy molding material to improve the above-mentioned properties of the epoxy molding material.

[0197] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A modified epoxy resin, characterized in that The modified epoxy resin is an epoxy resin modified with a flexible organic segment, and the modification comprises the following steps: reacting an epoxy resin and a flexible organic chain segment compound in a solvent to obtain the flexible organic chain segment-modified epoxy resin; The flexible organic chain segment compound is a compound having active groups at both ends; the active groups are selected from one or more of hydroxyl, carboxyl and amino groups.

2. The modified epoxy resin according to claim 1, wherein The epoxy resin is a polyaromatic epoxy resin selected from one or more of o-cresol novolac epoxy resin, phenol biphenyl novolac epoxy resin, biphenyl liquid crystal epoxy resin, o-cresol novolac epoxy resin and 1,5-diepoxynaphthalene resin; Preferably, the flexible organic segment compound is selected from one or more of double-terminated hydroxypropyl polymethylsiloxane, double-terminated aminopropyl polymethylsiloxane, hydroxy-terminated polybutadiene, sebacic acid, suberic acid, adipic acid, decanediol, Z-type perfluoropolyether tetraol and polycarbonate diol; Preferably, the solvent is selected from one or more of dichloromethane, chloroform, acetone, toluene, carbon tetrachloride and ether.

3. The modified epoxy resin according to claim 1, wherein The mass ratio of the epoxy resin to the flexible organic chain segment compound is (5-20): (2-10); Preferably, the amount of the solvent and the epoxy resin is such that 5 to 20 g of epoxy resin corresponds to every 100 to 300 mL of solvent.

4. The modified epoxy resin according to claim 1, wherein The reaction is carried out at 20-30°C; Preferably, the reaction time is 5 to 15 hours.

5. A low-stress epoxy molding compound, characterized in that: The invention comprises, in parts by mass, 6 to 7.5 parts of epoxy resin, 5 to 8 parts of phenolic resin, 65 to 90 parts of inorganic filler, 0.1 to 1.5 parts of curing accelerator, 0.1 to 5 parts of stress absorber, 0.1 to 1.5 parts of silane coupling agent, 0.1 to 1.5 parts of flame retardant, 0.1 to 1.5 parts of release agent, 0 to 0.5 parts of ion scavenger, 0.01 to 0.5 parts of fumed silicon and 0 to 0.5 parts of colorant; wherein, the epoxy resin comprises epoxy resin I and epoxy resin II, the epoxy resin II is the modified epoxy resin according to claim 1; the mass of the epoxy resin II is 70% to 80% of the total mass of the epoxy resin.

6. The epoxy molding compound according to claim 5, characterized in that: The epoxy resin I is an unmodified epoxy resin selected from one or more of biphenyl liquid crystal epoxy resin, dicyclopentadiene phenol epoxy resin, 1,5-diepoxynaphthalene resin, epoxy resin containing naphthalene ring, epoxide of aralkyl phenol resin, trimethylolpropane epoxy resin and ester ring epoxy resin.

7. The epoxy molding compound according to claim 5, wherein: The phenolic resin is selected from one or more of phenol novolac resin, cresol novolac type epoxy resin, biphenyl novolac resin, triphenylmethane type phenolic resin, naphthol novolac resin, aralkyl aldehyde resin and biphenyl novolac resin; Preferably, the inorganic filler is modified silica or unmodified silica; the silica is preferably fused crystallized spherical silica; the particle size of the inorganic filler is 1 to 75 μm; Preferably, the modifying agent is selected from one or more of an alkoxysilane compound having at least one of a primary amino group, a secondary amino group, and a tertiary amino group, an alkoxysilane compound having an epoxy group, an alkoxysilane compound having a mercapto group, an alkoxysilane compound having an alkyl group, an alkoxysilane compound having a urea group, and an alkoxysilane compound having a vinyl group, preferably an alkoxysilane compound having an epoxy group; Preferably, the stress absorber is a styrene-butadiene copolymer and its derivatives, selected from one or more of acrylonitrile-butadiene-styrene copolymer, epoxy-terminated styrene-butadiene-styrene block copolymer, epoxidized styrene-butadiene-styrene block copolymer, styrene-butadiene rubber, carboxyl-terminated liquid nitrile rubber and hydroxyl-terminated liquid nitrile rubber, preferably one or more of epoxy-terminated styrene-butadiene-styrene block copolymer and styrene-butadiene rubber; Preferably, the release agent is selected from one or more of oxidized or non-oxidized polyethylene wax, carnauba wax, stearic acid and synthetic paraffin wax, preferably one or more of carnauba wax and synthetic paraffin wax; Preferably, the ion capture agent is selected from one or more of a cation capture agent, anion capture agent and anion-cation capture agent.

8. A method for preparing the epoxy molding compound according to claim 5, characterized in that: The following steps are involved: Stirring and mixing the components uniformly according to a certain proportion, and then extruding and molding to obtain the epoxy molding compound; Preferably, the extrusion temperature is 80-130°C.

9. The preparation method according to claim 8, characterized in that The preparation method specifically comprises the following steps: (1) stirring the modified epoxy resin, stress absorber, flame retardant, release agent, and ion scavenger at 0-10° C. and 200-800 rpm for 5-10 minutes to mix uniformly; (2) Add inorganic filler, fumed silica, and colorant, and continue stirring at 0-10°C and 200-800 rpm for 8-15 minutes; (3) Add phenolic resin and curing accelerator, and continue stirring at 0-10°C and 200-800 rpm for 3-5 minutes; (4) adding a silane coupling agent at 50-300 rpm, and continuing to stir at 0-10° C. and 200-800 rpm for 10-30 min to obtain a mixed slurry; (5) Extruding through a twin-screw extrusion process, cooling and crushing, and then pre-pressing and molding to obtain the epoxy molding compound.

10. Use of the modified epoxy resin according to any one of claims 1 to 4, the epoxy molding compound according to any one of claims 5 to 7, or the preparation method according to any one of claims 8 to 9 in semiconductor packaging.

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