Epoxy resin composition, semiconductor device, and method for manufacturing a semiconductor device

Abstract

The present invention suppresses unevenness in the distribution of a filler dispersed in a sealing material (cured product) that covers an electrode connection part. An epoxy resin composition which contains (A) an epoxy resin, (B) a curing agent, (C) a filler and (D) an ionic compound, at least either the cation or the anion of which is organic.

Description

Technical Field

[0001] The present invention relates to an epoxy resin composition, a semiconductor device, and a method for manufacturing a semiconductor device.

Background Art

[0002] As a technique for mounting a semiconductor element on a substrate, flip chip mounting is known. Flip chip mounting is a mounting method in which a semiconductor element having protruding electrodes (element-side electrodes) called bumps formed on its surface is directly connected to electrodes (substrate-side electrodes) provided on the surface of a substrate such as a wiring substrate. Further, in flip chip mounting, in order to protect the semiconductor element, the substrate connected to the semiconductor element, and the bumps, after filling an underfill between the semiconductor element and the substrate, it is heat-cured.

[0003] As this underfill, an epoxy resin composition mainly containing an epoxy resin is mainly used (see, for example, Patent Document 1). On the other hand, the epoxy resin, the semiconductor element, and the substrate each have different coefficients of linear expansion. Therefore, if the stress generated at the electrode connection portion between the element-side electrode and the substrate-side electrode due to temperature change cannot be absorbed by the sealing material (the cured product of the underfill) covering the electrode connection portion, cracks may occur in the connection portion. In order to suppress the occurrence of these cracks, in addition to the epoxy resin, the underfill usually contains a filler made of silica, alumina, etc. having a relatively small coefficient of linear expansion.

[0004] On the other hand, in recent flip-chip mounting, metal pillars such as copper pillars are being used instead of bumps as components that make up the electrodes, from the viewpoint of narrow pitch. In such flip-chip mounting, it is known that during the process of heating and curing the underfill that is filled to cover the connection part, the uniformly dispersed filler in the underfill may separate and aggregate, and harden in that state. When such a phenomenon occurs, if the filler dispersed in the encapsulant (cured underfill) covering the electrode connection part is distributed in a biased manner toward the semiconductor element side or the substrate side relative to the connection interface of the electrode connection part, the connection reliability will decrease. Furthermore, it is presumed that such separation and aggregation of filler and bias in filler distribution are due to the electrophoresis of the filler in the underfill that is filled to surround the electrode connection part caused by the potential difference that arises from the difference in materials that make up the electrode connection surface on the element side and the electrode connection surface on the substrate side. For this reason, epoxy resin compositions suitable for suppressing the bias in the filler distribution in the encapsulant have been proposed (Patent Document 2). This epoxy resin composition contains, in addition to the epoxy resin and curing agent, 0.1 to 10% by mass of a first silica filler with an average particle size of 10 nm to 100 nm, 47 to 75% by mass of a second silica filler with an average particle size of 0.3 μm to 2 μm, and 0.1 to 8% by mass of an elastomer, with the first and second silica fillers totaling 50.1 to 77% by mass. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-145290 [Patent Document 2] International Publication No. 2015 / 079708 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The technology described in Patent Document 2 is useful for improving connection reliability. However, the technology described in Patent Document 2 requires the use of predetermined amounts of two types of silica fillers and elastomers having predetermined particle sizes in order to improve connection reliability, which imposes certain constraints on the compositional design of the epoxy resin composition. Therefore, there is a need to broaden the options for compositional design in order to improve connection reliability, similar to the technology described in Patent Document 2, while also making it easier to address a variety of other needs.

[0007] The present invention has been made in view of the above circumstances, and aims to provide an epoxy resin composition having a novel composition that can suppress the uneven distribution of fillers dispersed in a sealing material (cured product) covering an electrode connection, a semiconductor device made using the same, and a method for manufacturing the semiconductor device. [Means for solving the problem]

[0008] The above problems are solved by the present invention as follows. That is, the epoxy resin composition of the present invention is characterized by comprising (A) epoxy resin, (B) curing agent, (C) filler, and (D) ionic compound.

[0009] In one embodiment of the epoxy resin composition of the present invention, it is preferable that the (D) ionic compound comprises at least one selected from the group consisting of pyridinium-based ionic compounds, imidazolium-based ionic compounds, ammonium-based ionic compounds, phosphonium-based ionic compounds, pyrrolidinium-based ionic compounds, piperidinium-based ionic compounds, sulfonate-based ionic compounds, and iodine-based ionic compounds.

[0010] Another embodiment of the epoxy resin composition of the present invention is in which the (D) ionic compound is At least one cation selected from the group consisting of pyridinium-based cations, imidazolium-based cations, ammonium-based cations, pyrrolidinium-based cations, piperidinium-based cations, and phosphonium-based cations, <ii>It is preferable that the material contains at least one anion selected from the group consisting of sulfonylimid anions, sulfonate anions, hexafluorophosphate anions, bis(trifluoromethylsulfonyl)imide anions, imidodisulfurylfluoride anions, and iodine anions.

[0011] In another embodiment of the epoxy resin composition of the present invention, it is preferable that the (D) ionic compound is an ionic liquid.

[0012] In other embodiments of the epoxy resin composition of the present invention, it is preferable that the (D) ionic compound has a reactive group.

[0013] In another embodiment of the epoxy resin composition of the present invention, it is preferable that the content ratio of the (D) ionic compound is 0.0001% to 3.1% by mass relative to the total amount of the epoxy resin composition.

[0014] In another embodiment of the epoxy resin composition of the present invention, it is preferable that the content ratio of the (D) ionic compound is 0.001% by mass or more and 1.2% by mass or less, based on the total amount of the epoxy resin composition.

[0015] Another embodiment of the epoxy resin composition of the present invention is in which the (D) ionic compound is (D-1)1-butyl-1-methylpyrrolidinium=bis(trifluoromethylsulfonyl)imide, (D-2) Tributyldodecylphosphonium = bis(trifluoromethanesulfonyl)imide, (D-3) 1-Hexyl-4-methylpyridinium=bis(trifluoromethanesulfonyl)imide, (D-4) Trimethylpropylammonium = bis(trifluoromethanesulfonyl)imide, (D-5)4-(2-ethoxyethyl)-4-methylmorpholinium=bis(trifluoromethanesulfonyl)imide, (D-6) Methyltrioctylammonium = bis(trifluoromethanesulfonyl)imide, (D-7) Tributylmethylammonium = bis(trifluoromethanesulfonyl)imide, (D-8) 1-Butyl-3-dodecylimidazolium=bis(trifluoromethanesulfonyl)imide, (D-9) Methyltrioctylammonium tosylate, (D-10) Tributyldodecylphosphonium tosylate, (D-11) Tributyldodecylphosphonium=dodecylbenzenesulfonate, (D-12) N-oleyl-N,N-di(2-hydroxyethyl)-N-methylammonium=bis(trifluoromethanesulfonyl)imide, (D-13) Tributyl[3-(trimethoxysilyl)propyl]phosphonium=1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]methanesulfonamide, (D-14) Methyltrioctylammoniumimidodisulfurylfluoride, (D-15) Tetrabutylammonium hexafluorophosphate, and, (D-16) Methyltrioctylammonium hexafluorophosphate Preferably, it includes at least one selected from the group consisting of the following:

[0016] In another embodiment of the epoxy resin composition of the present invention, it is preferable that the epoxy resin (A) comprises a liquid epoxy resin.

[0017] In another embodiment of the epoxy resin composition of the present invention, it is preferable that the (A) epoxy resin comprises at least one selected from the group consisting of bisphenol F type epoxy resin, bisphenol A type epoxy resin, biphenyl type epoxy resin, aminophenol type epoxy resin, and naphthalene type epoxy resin.

[0018] Another embodiment of the epoxy resin composition of the present invention includes, as the (C) filler, a (C1) large-diameter filler having an average particle diameter of 0.2 μm or more, and the content ratio of the (C1) large-diameter filler is preferably 35% to 70% by mass based on the total amount of the epoxy resin composition.

[0019] In another embodiment of the epoxy resin composition of the present invention, the average particle diameter of the (C1) large-diameter filler is preferably 0.2 to 3.0 μm.

[0020] Another embodiment of the epoxy resin composition of the present invention includes, as the (C) filler, a (C2) small-diameter filler having an average particle diameter of less than 0.2 μm, and the average particle diameter of the (C2) small-diameter filler is preferably 5 nm to 120 nm.

[0021] Another embodiment of the epoxy resin composition of the present invention further includes an (E) additive, and it is preferable that the (E) additive includes core-shell rubber particles.

[0022] Another embodiment of the epoxy resin composition of the present invention is preferably used as a sealing material for semiconductor devices.

[0023] The semiconductor device of the present invention is characterized by including a substrate, a semiconductor element disposed on the substrate, and a cured product of the epoxy resin composition of the present invention that seals the gap between the semiconductor element and the substrate.

[0024] The manufacturing method of the semiconductor device of the present invention includes a step of filling the gap between a substrate and a semiconductor element disposed on the substrate with the epoxy resin composition of the present invention, and a step of curing the epoxy resin composition.

Effects of the Invention

[0025] According to the present invention, it is possible to provide an epoxy resin composition having a novel composition that can suppress the uneven distribution of fillers dispersed in a sealing material (cured product) covering an electrode connection, a semiconductor device made using the same, and a method for manufacturing the semiconductor device. [Brief explanation of the drawing]

[0026] [Figure 1] This is a cross-sectional view showing an example of the cross-sectional structure of a semiconductor device. [Modes for carrying out the invention]

[0027] <Epoxy resin composition> The epoxy resin composition of this embodiment is characterized by comprising (A) an epoxy resin, (B) a curing agent, (C) a filler, and (D) an ionic compound in which at least one of the cation or anion is an organic substance. Therefore, when the epoxy resin composition is filled between an electronic element such as a semiconductor element and a substrate during flip-chip mounting and then heat-cured, using the epoxy resin composition of this embodiment as the epoxy resin composition can suppress the uneven distribution of the filler dispersed in the sealing material (cured product) covering the electrode connection part. For this reason, it is easy to obtain semiconductor devices and other electronic devices with high connection reliability. The details of why such effects are obtained are unknown, but the inventors presume it is as follows.

[0028] First, a potential difference arises at the connection interface or near the connection point between the electrode on the device side and the electrode on the substrate side, where the metal materials constituting the electrode connection surface on the device side and the metal materials constituting the electrode connection surface on the substrate side are different from each other. For this reason, in conventional epoxy resin compositions that do not use ionic compounds, charged fillers contained in the epoxy resin composition filled around the electrode connection point tend to move to either the semiconductor device side or the substrate side by electrophoresis. Therefore, it is thought that an uneven distribution of fillers dispersed in the encapsulant (cured product) covering the electrode connection point is likely to occur.

[0029] However, when the epoxy resin composition of this embodiment is used, the charge of the filler is released to the outside via a conductive ionic compound. As a result, the filler, with its reduced charge, is less likely to move to either the semiconductor element side or the substrate side. Therefore, it is believed that this can suppress the uneven distribution of filler dispersed in the encapsulant (cured product) covering the electrode connection.

[0030] As mentioned above, in flip-chip mounting using metal pillars as electrode members, it is known that separation and aggregation of fillers contained in the epoxy resin composition, and uneven distribution of fillers in the encapsulant, can occur. Therefore, the epoxy resin composition of this embodiment is particularly suitable for use as an underfill when manufacturing semiconductor devices by flip-chip mounting using metal pillars as electrode members. However, if substantially the same phenomena as described above occur when manufacturing various electronic devices such as semiconductor devices using conventional general epoxy resin compositions, the epoxy resin composition of this embodiment can of course also be used in the manufacture of semiconductor devices manufactured by mounting methods other than flip-chip mounting using metal pillars, or in the manufacture of various electronic devices other than semiconductor devices. Next, the details of each component constituting the epoxy resin composition of this embodiment will be described below.

[0031] (A) Epoxy resin The epoxy resin used in the epoxy resin composition of this embodiment is not particularly limited as long as it is one of the various epoxy resins generally used for semiconductor encapsulation, but from the viewpoint of viscosity and injectability, it is preferable to use a liquid epoxy resin. Furthermore, the epoxy resin blended into the epoxy resin composition may be one type of epoxy resin only, or two or more epoxy resins may be used in combination. The number of epoxy groups contained in one molecule of epoxy resin may be one or more, but it is usually preferable to have two or more. The upper limit of the number of epoxy groups is not particularly limited, but it is usually preferable to have five or fewer. The epoxy resin may be one of the various epoxy resins generally used for semiconductor encapsulation, and is not particularly limited.

[0032] Typical examples of epoxy resins include aliphatic epoxy resins and aromatic epoxy resins, with aromatic epoxy resins being preferred. Examples of aromatic epoxy resins include, but are not limited to, bisphenol A type epoxy resins such as p-glycidyloxyphenyldimethyltrisbisphenol A diglycidyl ether; bisphenol F type epoxy resins; novolac type epoxy resins; fluorene type epoxy resins; biphenyl aralkyl epoxy resins; diepoxy resins such as p-tert-butylphenyl glycidyl ether and 1,4-phenyldimethanol diglycidyl ether; biphenyl type epoxy resins such as 3,3',5,5'-tetramethyl-4,4'-diglycidyloxybiphenyl; aminophenol type epoxy resins such as diglycidylaniline, diglycidyltoluidine, triglycidyl-p-aminophenol, and tetraglycidyl-m-xylylenediamine; naphthalene type epoxy resins; and epoxy resins having a plant-derived skeleton.

[0033] Among these, bisphenol F type epoxy resin, bisphenol A type epoxy resin, biphenyl type epoxy resin, aminophenol type epoxy resin, and naphthalene type epoxy resin are preferred.

[0034] (B) Hardener The curing agent used in the epoxy resin composition of this embodiment may be any commonly used curing agent and is not particularly limited. The amount of curing agent added is preferably such that the stoichiometric equivalent ratio (curing agent equivalent / epoxy group equivalent) with the epoxy resin is 0.6 to 1.5, and more preferably 0.7 to 1.2.

[0035] Examples of curing agents include amine-based curing agents, acid anhydride-based curing agents, and phenol-based curing agents. Furthermore, when incorporating a curing agent into an epoxy resin composition, one type of curing agent may be used alone, or two or more curing agents may be used in combination.

[0036] Specific examples of amine-based curing agents include aliphatic polyamines such as triethylenetetraamine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, and 2-methylpentamethylenediamine; alicyclic polyamines such as isophoronediamine, 1,3-bisaminomethylcyclohexane, bis(4-aminocyclohexyl)methane, norbornenediamine, and 1,2-diaminocyclohexane; piperazine-type polyamines such as N-aminoethylpiperazine and 1,4-bis(2-amino-2-methylpropyl)piperazine; diethyltoluenediamine, dimethylthiotoluenediamine, 4,4'-diamino-3,3'-diethyldiphenylmethane, bis(methylthio)toluenediamine, diaminodiphenylmethane, m-phenylenediamine, and diaminodiphenylsulfonediamine. N, To Aromatic polyamines such as limethylenebis(4-aminobenzoate) and polytetramethylene oxide-di-p-aminobenzoate are examples. Commercially available products include Epicure-W, Epicure-Z (product name, Yoka Shell Epoxy Co., Ltd.), jER Cure®-W, jER Cure®-Z (product name, Mitsubishi Chemical Corporation), Kaya Hard AA, Kaya Hard AB, Kaya Hard AS (product name, Nippon Kayaku Co., Ltd.), Totamine HM-205 (product name, Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), Adeka Hardner EH-101 (product name, ADEKA Corporation), Epomic Q-640, Epomic Q-643 (product name, Mitsui Chemicals, Inc.), DETDA80 (product name, Lonza), Totamine HM-205 (product name, Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), etc.

[0037] Specific examples of acid anhydride-based curing agents include alkylated tetrahydrophthalic anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride, as well as hexahydrophthalic anhydride, methylhymic anhydride, succinic anhydride substituted with alkenyl groups, methylnadic anhydride, and glutaric anhydride.

[0038] Specific examples of phenolic curing agents include monomers, oligomers, and polymers in general that have phenolic hydroxyl groups, such as phenol novolac resins and their alkylated or allylated derivatives, cresol novolac resins, phenol aralkyl (including phenylene and biphenylene skeletons) resins, naphthol aralkyl resins, triphenolmethane resins, and dicyclopentadiene-type phenolic resins.

[0039] (C) Filler The epoxy resin composition of this embodiment contains a filler, primarily to improve thermal cycling resistance and moisture resistance by reducing the coefficient of thermal expansion of the sealed portion (cured product). The filler is not particularly limited as long as it has the effect of reducing the coefficient of thermal expansion of the cured product, and any known filler can be used as appropriate, such as alumina filler or silica filler. Furthermore, the filler may be surface-treated with a silane coupling agent or the like.

[0040] The particle size and amount of filler incorporated into the epoxy resin composition are not particularly limited, but it is generally preferable that the epoxy resin composition of this embodiment contains a filler with an average particle size of at least 0.2 μm ((C1) large-diameter filler). The average particle size of the large-diameter filler is not particularly limited as long as it is 0.2 μm or more, but from a practical standpoint, it is preferable to be between 0.2 μm and 3.0 μm. Furthermore, the content ratio of the large-diameter filler incorporated into the epoxy resin composition is preferably 35% to 70% by mass, more preferably 40% to 69% by mass, and even more preferably 45% to 68% by mass, based on the total amount of the epoxy resin composition. When the content ratio of the large-diameter filler is 35% by mass or more, the coefficient of linear expansion of the cured product becomes smaller, making it easier to improve thermal cycle resistance, and when it is 70% by mass or less, the viscosity of the epoxy resin composition becomes lower, making it easier to improve the injectability of the epoxy resin composition.

[0041] Furthermore, it is more preferable to further incorporate fillers ((C2) small-diameter fillers) with an average particle size of less than 0.2 μm (200 nm) into the epoxy resin composition of this embodiment in combination with the large-diameter fillers. By combining large-diameter and small-diameter fillers and incorporating them into the epoxy resin composition, it becomes easier to suppress the uneven distribution of fillers dispersed in the sealing material (cured product) covering the electrode connection. In addition, it becomes easier to increase the amount of filler packed into the epoxy resin composition. The average particle size of the small-diameter fillers is not particularly limited as long as it is less than 0.2 μm, but from a practical standpoint, it is preferable to be between 5 nm and 120 nm.

[0042] The shape of the large-diameter filler is not particularly limited and may be spherical, amorphous, or flaky. The shape of the small-diameter filler is also not particularly limited and may be spherical, amorphous, or flaky. However, the shape of the small-diameter filler produced by wet synthesis is spherical. In this specification, the average particle size of the large-diameter filler refers to the volume-average particle size D50 value (the particle size that represents 50% of the cumulative distribution from the small-diameter side) measured using a laser diffraction particle size distribution analyzer (Beckman Coulter LS13320). The measurement was performed under the following conditions: a sample was prepared by mixing 5 mg of filler with 50 mg of dispersant and dispersing it using an ultrasonic disperser for 10 minutes, with a flow rate of 50 ml / second, a measurement time of 90 seconds, pure water as the solvent, and a solvent refractive index of 1.333. Furthermore, the average particle size of the small-diameter fillers was measured based on images of the fillers taken at magnifications of 100,000 to 1,000,000 times using a field emission scanning electron microscope (FE-SEM) (JEOL JSM-7500). Here, the particle size of the fillers refers to the value obtained by binarizing the image using image processing software (Win ROOF), separating the filler portion as a circle using the circular separation function, and measuring the diameter of that circle.

[0043] (D) Ionic compounds The epoxy resin composition of this embodiment contains an ionic compound composed of a cation and anion, where at least one of the cation or anion is an organic substance. Known ionic compounds can be used as the ionic compound. It is particularly preferable that at least a portion of this ionic compound is soluble in the epoxy resin within the operating temperature range of the epoxy resin composition of this embodiment. Soluble means that at room temperature (25°C), the amount of ionic compound dissolved in the epoxy resin composition is 0.0005 g or more per 100 g of epoxy resin. The amount of ionic compound dissolved per 100 g of epoxy resin is preferably 0.001 g or more, and more preferably 0.003 g or more. The melting point of the ionic compound is not particularly limited, but is preferably 250°C or lower, preferably 100°C or lower, and more preferably below room temperature (25°C). Ionic compounds with a melting point of 100°C or lower are known as "ionic liquids." The lower limit of the melting point of the ionic compound is not particularly limited, but is preferably -100°C or higher for practical purposes.

[0044] It is preferable that the ionic compound has a reactive group within its molecule. Examples of such reactive groups include trimethylsilyl groups, hydroxyl groups, carboxyl groups, aldehyde groups, hydroxyl groups, carboxyl groups, nitro groups, amino groups, sulfo groups, and methacrylic groups. When an ionic compound having a reactive group is incorporated into an epoxy resin composition, during the curing of the epoxy resin composition, the ionic compound reacts with the resin matrix constituting the cured body and becomes fixed in the cured body. This makes it easier to suppress the leakage of the ionic compound from the encapsulant (cured body) of the semiconductor device, which can cause various problems due to contamination of the vicinity of the encapsulant by the ionic compound. Furthermore, since it is easier to suppress the leakage of the ionic compound from the cured body, it is also easier to increase the amount of ionic compound incorporated into the epoxy resin composition. Therefore, the degree of freedom in designing the composition of the epoxy resin composition of this embodiment can be further increased to meet various needs. In addition, if the ionic compound includes chain-like cation molecules and / or anionic molecules, it is preferable that the reactive group is provided at the end of the chain-like molecule constituting the ionic compound. This makes it easier to react the ionic compound with the resin matrix constituting the cured epoxy resin composition and fix it in the cured body during curing. Furthermore, while various compounds can be used as cations and anions that constitute the ionic compound, it is preferable to use cations and anions that do not have a trifluoromethyl group in order to reduce the release of PFAS (perfluoroalkyl compounds, polyfluoroalkyl compounds and their salts) into the environment. In this case, ionic compounds in which each of the cation and anion is composed of molecules that do not contain a trifluoromethyl group are more preferable.

[0045] Examples of ionic compounds that can be used include pyridinium-based ionic compounds, imidazolium-based ionic compounds, ammonium-based ionic compounds, phosphonium-based ionic compounds, pyrrolidinium-based ionic compounds, piperidinium-based ionic compounds, sulfonate-based ionic compounds, and iodine-based ionic compounds. Furthermore, when focusing on suitable combinations of cations and anions, the ionic compounds are: At least one cation selected from the group consisting of pyridinium-based cations, imidazolium-based cations, ammonium-based cations, pyrrolidinium-based cations, piperidinium-based cations, and phosphonium-based cations, <ii>It is preferable that the material contains at least one anion selected from the group consisting of sulfonylimid anions, sulfonate anions, hexafluorophosphate anions, bis(trifluoromethylsulfonyl)imide anions, imidodisulfurylfluoride anions, and iodine anions.

[0046] Examples of pyridinium-based ionic compounds include 1-hexyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium chloride, 1-butyl-4-methylpyridinium hexafluorophosphate, 1-butyl-4-methylpyridinium iodide, 4-methyl-N-butylpyridinium tetrafluoroborate, 1-butylpyridinium bromide, 1-(3-cyanopropyl)pyridinium chloride, 1-ethylpyridinium tetrafluoroborate, and 3-methyl-1-propylpyridinium bis(trifluoromethylsulfonyl)imide.

[0047] Examples of imidazolium-based ionic compounds include 1-butyl-3-dodecylimidazolium bis(trifluoromethanesulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-allyl-3-methylimidazolium bromide, 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium dicyanamide, 1-allyl-3-methylimidazolium iodide, 1-benzyl-3-methylimidazolium chloride, 1-benzyl-3-methylimidazolium hexafluorophosphate, 1-benzyl-3-methylimidazolium tetrafluoroborate, and 1,3-bis(cyanomethyl)imidazolium Bis(trifluoromethylsulfonyl)imide, 1,3-bis(cyanomethyl)imidazolium chloride, 1,3-bis(3-cyanopropyl)imidazolium Bis(trifluoromethylsulfonyl)imide, 1,3-bis(3-cyanopropyl)imidazolium chloride, 1-butyl-2,3-dimethylimidazolium chloride, 1-butyl-2,3-dimethylimidazolium hexafluorophosphate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 4-(3-butyl-1-imidazolio)-1-butanesulfonate, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium Examples include mubis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium dibutyl phosphate, 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium hexafluoroantimonate, and 1-butyl-3-methylimidazolium hexafluorophosphate. A commercially available example is 356-41191.

[0048] Ammonium-based ionic compounds include tributylmethylammonium bis(trifluoromethanesulfonyl)imide, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide, 4-(2-ethoxyethyl)-4-methylmorpholinium bis(trifluoromethanesulfonyl)imide, butyltrimethylammonium bis(trifluoromethanesulfonyl)imide, ethyldimethylpropylammonium bis(trifluoromethylsulfonyl)imide, 2-hydroxyethyltrimethylammonium lactate, methyl-trioctylammonium bis(trifluoromethylsulfonyl)imide, methyltrioctylammonium thiosalicylate, tetrabutylammonium nonafluorobutanesulfonate, tetraethylammonium trifluoromethanesulfonate, tetraheptylammonium chloride, tributylmethylammonium dibutyl phosphate, tributylmethylammonium methylsulfate, triethylmethylammonium dibutyl phosphate, tris(2-hydroxyethyl)methylammonium methylsulfate, trioctylmethylammonium thiocyanate, p-toluenesulfonate, N, Examples of such products include N-diethyl-N-(2-methoxyethyl)-N-methylammonium methoxyacetate, tetrabutylammonium acetate, tetraethylammonium trifluoromethanesulfonate, tributylmethylammonium dibutylphosphate, methyltrioctylammonium tosylate, N-oleyl-N,N-di(2-hydroxyethyl)-N-methylammonium bis(trifluoromethanesulfonyl)imide, methyltrioctylammoniumimide disulfuryl fluoride, and tetrabutylammonium hexafluorophosphate. Examples of commercially available products include T1745, IL2-3, T2694, ILA2-9, ILA48-32, and 669962.

[0049] Examples of phosphonium-based ionic compounds include tributyldodecylphosphonium. Bis(trifluoromethanesulfonyl)imide, tetrabutylphosphonium methanesulfonate, tributylmethylphosphonium dibutyl phosphate, tributylmethylphosphonium methylsulfate, triethylmethylphosphonium dibutyl phosphate, trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide, p-toluenesulfonate tributyldodecylphosphonium, trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate, trihexyltetradecylphosphonium bromide, trihexyltetradecylphosphonium chloride, trihexyltetradecylphosphonium decanoate, trihexyltetradecylphosphonium dicyanamide, 3-(triphenylphosphonio)propane-1-sulfonate, 3-(triphenylphosphonio)propane-1-sulfonate tosylate, 1-butanaminonium, N,N-dibutyl-N-methyl, dibutyl phosphate, tributyldodecylphosphonium Examples include tosylate, tributyldodecylphosphonium dodecylbenzenesulfonate, and tributyl[3-(trimethoxysilyl)propyl]phosphonium 1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]methanesulfonamide, with ILAP3-3 being a commercially available example.

[0050] Examples of pyrrolidinium-based ionic compounds include 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium bromide, 1-butyl-1-methylpyrrolidinium chloride, 1-butyl-1-methylpyrrolidinium dicyanamide, 1-butyl-1-methylpyrrolidinium hexafluorophosphate, 1-butyl-1-methylpyrrolidinium iodide, 1-butyl-1-methylpyrrolidinium tetrafluoroborate, 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, 1-ethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-ethyl-1-methylpyrrolidinium bromide, 1-ethyl-1-methylpyrrolidinium hexafluorophosphate, 1-ethyl-1-methylpyrrolidinium tetrafluoroborate, and 1-butyl-1-methylpyrrolidinium Examples include tetrafluoroborate, and commercially available products such as 322-87291 can be cited as an example.

[0051] Examples of piperidinium-based ionic compounds include 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl)imide and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide.

[0052] Examples of sulfonate-based ionic compounds include methyltrioctylammonium tosylate, tributyldodecylphosphonium tosylate, and tributyldodecylphosphonium dodecylbenzenesulfonate.

[0053] Examples of iodine-based ionic compounds include 1,3-dimethylimidazolium iodide, 1-ethyl-3-methylimidazolium iodide, 1-ethyl-3-propylimidazolium iodide, 1-butyl-3-methylimidazolium iodide, 1-hexyl-3-methylimidazolium iodide, 1-allyl-3-methylimidazolium iodide, 1-allyl-3-ethylimidazolium iodide, and 1,2-dimethyl-3-propylimidazolium iodide.

[0054] Among these, the ionic compounds are: (D-1) 1-butyl-1-methylpyrrolidinium = bis(trifluoromethylsulfonyl)imide, (D-2) tributyldodecylphosphonium = bis(trifluoromethanesulfonyl)imide, (D-3) 1-hexyl-4-methylpyridinium = bis(trifluoromethanesulfonyl)imide, (D-4) trimethylpropylammonium = bis(trifluoromethanesulfonyl)imide, (D-5) 4-(2-ethoxyethyl)-4-methylmorpholinium = bis(trifluoromethanesulfonyl)imide, (D-6) methyltrioctylammonium = bis(trifluoromethanesulfonyl)imide, (D-7) tributylmethylammonium = bis(trifluoromethanesulfonyl)imide, (D-8) 1-butyl-3-dodecylimidazolium = bis(tri (D-9) fluoromethanesulfonyl)imide, (D-10) methyltrioctylammonium tosylate, (D-11) tributyldodecylphosphonium dodecylbenzenesulfonate, (D-12) N-oleyl-N,N-di(2-hydroxyethyl)-N-methylammonium bis(trifluoromethanesulfonyl)imide, (D-13) tributyl[3-(trimethoxysilyl)propyl]phosphonium=1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]methanesulfonamide, (D-14) methyltrioctylammonium imide disulfuryl fluoride, (D-15) tetrabutylammonium hexafluorophosphate, and (D-16) methyltrioctylammonium hexafluorophosphate are preferred. Furthermore, the ionic compound incorporated into the epoxy resin composition may be a single ionic compound or a combination of two or more ionic compounds.

[0055] The content ratio of ionic compounds to the total amount of epoxy resin composition is not particularly limited, but it is preferably between 0.0001% by mass (1 ppm) and 3.1% by mass (31,000 ppm). By setting the content ratio of ionic compounds to 0.0001% by mass (1 ppm) or more, it becomes easier to more reliably suppress the uneven distribution of fillers dispersed in the encapsulant (cured product) covering the electrode connection. Furthermore, by setting the content ratio of ionic compounds to 3.1% by mass (31,000 ppm) or less, it becomes easier to suppress the leakage of ionic compounds from the encapsulant (cured product) of the semiconductor device and the resulting contamination of the vicinity of the encapsulant by ionic compounds, which can cause various problems. The lower limit of the content ratio of ionic compounds is more preferably 0.001% by mass (10 ppm) or more, and 0.003 mass% It is even more preferable that the concentration be 30 ppm or higher. 、 It is even more preferable that the content is 0.005% by mass (50 ppm) or more. Furthermore, the upper limit of the ionic compound content is more preferably 3.0% by mass (30,000 ppm) or less, even more preferably 2.0% by mass (20,000 ppm) or less, even more preferably 1.2% by mass (12,000 ppm) or less, even more preferably 1.0% by mass (10,000 ppm) or less, even more preferably 0.5% by mass (5,000 ppm) or less, even more preferably 0.1% by mass (1,000 ppm) or less, and even more preferably 0.05% by mass (500 ppm) or less.

[0056] From a similar viewpoint, the content of the ionic compound per 100 parts by mass of epoxy resin containing two or more epoxy groups is preferably 0.002 parts by mass to 11 parts by mass. Furthermore, from the viewpoint of further improving injectability, the content of the ionic compound is more preferably greater than 0.8 parts by mass and 11 parts by mass or less, and even more preferably between 1 and 11 parts by mass.

[0057] Furthermore, the total amount of (A) epoxy resin and (D) ionic compound relative to the total amount of all organic components contained in the epoxy resin composition is preferably 85% by mass or less, and more preferably 82% by mass or less. By setting the total amount of (A) epoxy resin and (D) ionic compound relative to the total amount of all organic components to 85% by mass or less, it is possible to suppress the occurrence of curing defects when the epoxy resin composition is heated. The lower limit of the total amount of (A) epoxy resin and (D) ionic compound relative to the total amount of all organic components is not particularly limited, but in practice, it is preferably 40% by mass or more, and more preferably 50% by mass or more.

[0058] (E) Additives In addition to components (A) to (D), the epoxy resin composition of this embodiment may further contain various additives as needed. The additives are not particularly limited, but examples include core-shell type rubber particles, curing accelerators, and silane coupling agents. Agent, viscosity Examples of additives include desaturates, ion traps, leveling agents, antioxidants, defoamers, flame retardants, colorants, and reactive diluents. The types and amounts of these additives are in accordance with conventional methods. Details of some of these additives are described below.

[0059] Core-shell type rubber particles used as additives impart injectability to the epoxy resin composition and suppress peeling and migration of the epoxy resin composition after curing. Examples of core-shell structure rubber particles that undergo masterbatch treatment include rubber particles consisting of a core: polybutadiene and a shell: acrylic copolymer, or rubber particles consisting of a core: silicone resin and a shell: acrylic copolymer, etc. Among these, rubber particles consisting of a core: polybutadiene and a shell: acrylic copolymer are preferred because their low elastic modulus within the operating temperature range of the epoxy resin composition can reduce the shrinkage stress of the epoxy resin composition. Masterbatch treatment of core-shell structure rubber particles can be carried out with epoxy resin, acid anhydride or other curing agents, and epoxy resin, particularly bisphenol type epoxy resin, is preferred from the viewpoint of storage stability and avoidance of adverse effects on humidity. Examples of bisphenol type epoxy resins include bisphenol A type epoxy resin and bisphenol F type epoxy resin, with bisphenol F type epoxy resin being more preferred.

[0060] Curing accelerators used as additives impart an appropriate curing rate to the epoxy resin composition. Examples of curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole. Commercially available products include 2-phenyl-4-methylimidazole (product name: 2P4MZ) manufactured by Shikoku Kasei and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (product name: 2MZA) manufactured by Shikoku Kasei. Curing accelerators may be used alone or in combination of two or more types.

[0061] The silane coupling agent used as an additive provides adhesion between the epoxy resin composition and the semiconductor element or substrate. Examples of commercially available products include Z-6610, Z-6011, Z-6020, Z-6094, Z-6883, Z-6032, Z-6040, Z-6044, Z-6043, Z-6075, Z-6300, Z-6519, Z-6825, Z-6030, Z-6033, Z-6062, Z-6862, Z-6911, Z-6026, AZ-720, Z-6050 (all manufactured by Toray Dow Corning), KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE-502, KBE-50 3. Examples include KBM-5103, KBM-602, KBM-603, KBE-603, KBM-903, KBE-903, KBE-9103, KBM-573, KBM-575, KBE-585, KBM-1003, KBE-1003, KBM-802, KBM-803, KBE-846, KBE-9007, X-41-1053, X-41-1056, X-41-1059A, X-41-1805, X-41-1808, X-41-1810, KR-513, X-40-2672B, X-40-9272B, X-40-2651, etc. (all manufactured by Shin-Etsu Chemical Co., Ltd.). The silane coupling agents mentioned above may be used alone or in combination of two or more types.

[0062] The epoxy resin composition of this embodiment can be prepared by mixing and stirring at least components (A) to (D), and component (E) may be added as needed. The method of mixing and stirring is not particularly limited, and known mixing and stirring methods such as roll mills can be used. Furthermore, if the epoxy resin (A) used as a raw material is in solid form, it is preferable to liquefy it by heating or other means before mixing it with the other components. In addition, when preparing the epoxy resin composition, all raw material components may be mixed at once, or a primary mixture may be prepared by mixing some of the selected raw material components, and the remaining components may be mixed into the primary mixture. For example, when using a large-diameter filler (C1) as a filler (C), if it is difficult to uniformly disperse the large-diameter filler (C1) in the epoxy resin (A), a primary mixture of the epoxy resin (A) and the large-diameter filler (C1) may be prepared, and the remaining components may be mixed into this primary mixture.

[0063] <Applications of epoxy resin compositions, semiconductor devices, and methods for manufacturing the same> The epoxy resin composition of this embodiment can be used as a encapsulant for various electronic devices such as semiconductor devices. In particular, it is preferable to use it as a encapsulant for various electronic devices such as semiconductor devices that have an electrode connection portion surrounded by the encapsulant, where the first metal material constituting one electrode connection surface of the connection interface of the electrode connection portion and the second metal material constituting the other electrode connection surface are different. Here, the combination of the first metal material and the second metal material is not particularly limited as long as a potential difference is generated when the two are connected. However, (a) a combination of a first metal material selected from the group consisting of copper, copper alloys, silver, silver alloys, gold, and gold alloys, and a second metal material selected from the group consisting of tin and tin alloys, or (b) a combination of metal materials that generate a potential difference of approximately the same magnitude or greater than that of the combination in (a), is preferable. When resin encapsulation is performed using the epoxy resin composition of this embodiment during the manufacture of an electronic device equipped with such an electrode connection portion, the uneven distribution of fillers dispersed in the encapsulant (cured product) covering the electrode connection portion can be suppressed.

[0064] Furthermore, the semiconductor device of this embodiment may include a substrate, a semiconductor element disposed on the substrate, and a sealing material (a cured product of the epoxy resin composition of this embodiment) that seals the gap between the semiconductor element and the substrate. This semiconductor device includes an electrode connection portion where the electrode connection surface of the element-side electrode provided on the semiconductor element is connected to the electrode connection surface of the substrate-side electrode provided on the substrate, and the sealing material is arranged to surround this electrode connection portion as well. In the semiconductor device of this embodiment, it is particularly preferable that the element-side metal material constituting the electrode connection surface of the element-side electrode and the substrate-side metal material constituting the electrode connection surface of the substrate-side electrode provided on the substrate are different from each other, and the preferred combination of the two is the same as the preferred combination of the first metal material and the second metal material described above. The element-side electrode and the substrate-side electrode can be made of, for example, solder bumps or metal pillars, but it is preferable that the element-side electrode is made of a metal pillar such as a copper pillar.

[0065] The semiconductor device of this embodiment is manufactured by at least two steps: filling the gap between a substrate and a semiconductor element placed on the substrate with the epoxy resin composition of this embodiment (filling step), and curing the epoxy resin composition filled in the gap (curing step). Typically, prior to the filling step, a step is performed to form an electrode connection portion by connecting the electrode connection surface of the element-side electrode and the electrode connection surface of the substrate-side electrode with the surface of the semiconductor element on which the element-side electrode is provided facing the surface of the substrate on which the substrate-side electrode is provided (connecting step). Therefore, in the filling step, the epoxy resin composition is filled so as to surround the electrode connection portion, and the epoxy resin composition surrounding the electrode connection portion hardens in the curing step (becoming a cured product (sealant)).

[0066] Figure 1 is a cross-sectional view showing an example of the cross-sectional structure of a semiconductor device, specifically an SEM image taken with a scanning electron microscope (FE-SEM) of the cross-sectional structure near the electrode connection portion. As shown in Figure 1, a encapsulant 40, which is a cured epoxy resin composition filled in the filling process, is arranged near the electrode connection portion 30, which is composed of a substrate-side electrode 10 and an element-side electrode 20 connected to the substrate-side electrode 10, so as to surround the electrode connection portion 30 (in the figure, the encapsulant 40 is located between a pair of left and right electrode connection portions 30). In the example shown in Figure 1, the substrate-side electrode 10 is composed of a solder bump made of a tin alloy mainly containing tin, and the element-side electrode 20 is composed of a copper pillar, so a potential difference is generated when the two electrodes 10 and 20 are connected. Also, as shown in Figure 1, the encapsulant 40 is composed of a filler (the relatively white part of the encapsulant 40 in the figure) and a resin matrix (the relatively black part of the encapsulant 40 in the figure), which is the part other than the filler. Furthermore, the filler and resin matrix in the sealing material 40 can be distinguished by specifying the region corresponding to the sealing material 40 in the SEM image and performing image processing using image processing software. Such image processing is performed by binarizing the image based on the median value of the brightness distribution of the region corresponding to the specified sealing material 40.

[0067] On the other hand, the electrode connection portion 30 has a connection interface L formed between the electrode connection surface of the substrate-side electrode 10 and the electrode connection surface of the element-side electrode 20. Here, the region corresponding to the encapsulating material 40 can be divided into a semiconductor element-side region Ra and a substrate-side region Rb, based on an extension line of the connection interface L. In this case, the degree of bias in the distribution of filler dispersed in the encapsulating material 40 covering the electrode connection portion 30 can be quantitatively evaluated by the filler distribution index shown in equation (1) below. • Equation (1) Filler distribution index = 100 × a / b

[0068] Here, in equation (1), a is the filler occupancy rate within region Ra, and b is the filler occupancy rate within region Rb. The occupancy rates are calculated based on SEM images obtained by binarization, as illustrated in Figure 1. The series of image processing steps to calculate the filler distribution index were performed using ImageJ from the National Institutes of Health (NIH).

[0069] A filler distribution index of 100 means that the filler dispersed in the encapsulating material 40 is distributed most uniformly (the bias in the distribution is minimal). On the other hand, the further the filler distribution index is from 100, the greater the degree of bias in the distribution of the filler dispersed in the encapsulating material 40. Furthermore, if the filler distribution index is less than 100, it means that the filler is biased towards region Rb, and if it is greater than 100, it means that the filler is biased towards region Ra. Whether the filler tends to be biased towards region Ra or region Rb depends on the combination of the metal material constituting the electrode connection surface of the substrate-side electrode 10 and the metal material constituting the electrode connection surface of the element-side electrode 20. In the semiconductor device of this embodiment, the filler distribution index is preferably within the range of 100 ± 50, more preferably within the range of 100 ± 30, and even more preferably within the range of 100 ± 20. [Examples]

[0070] Specific examples of the present invention will be described below with reference to examples, but the present invention is not limited to the examples described below.

[0071] 1. Preparation of epoxy resin composition Examples 1 to 6 were created by mixing and stirring the raw materials using a roll mill to achieve the blending ratios shown in Tables 1 to 6. 51 The epoxy resin composition of Comparative Example 1 was prepared. The details of the components (A) to (E) used as raw materials are as follows.

[0072] 2. Raw material components used in the preparation of the epoxy resin composition (A) Epoxy resin a1: YDF8170 (Bisphenol F type, epoxy equivalent 158 ​​g / eq, number of epoxy groups: 2, manufactured by Nippon Steel Chemical & Material Co., Ltd.) a2: EXA-850CRP (Bisphenol A type, epoxy equivalent 172 g / eq, number of epoxy groups: 2, manufactured by DIC Corporation) a3: HP4032D (Naphthalene type, epoxy equivalent 140 g / eq, number of epoxy groups: 2, manufactured by DIC Corporation) a4:jER630 (aminophenol type, epoxy equivalent 98g / eq, number of epoxy groups: 3, manufactured by Mitsubishi Chemical Corporation) a5: YX7400 (Biphenyl type, epoxy equivalent 440 g / eq, number of epoxy groups: 2, manufactured by Mitsubishi Chemical Corporation)

[0073] (B) Hardener b1: HDAA (amine-based curing agent, 4,4'-diamino-3,3'-diethyldiphenylmethane, active hydrogen equivalent 63.5 g / eq, manufactured by Nippon Kayaku Co., Ltd.) b2: EtaCure 100 (amine-based curing agent, diethyl Ru Endiamine, active hydrogen equivalent 44.6 g / eq, manufactured by Albemarle. b3:HN5500 (acid anhydride Physical hardening agent (Activated hydrogen equivalent 168g / eq, manufactured by Hitachi Chemical Co., Ltd.) b4: MEH8006 (phenolic curing agent, active hydrogen equivalent 135 g / eq, manufactured by Meiwa Kasei Co., Ltd.)

[0074] (C) Filler (C1) Large diameter filler • SE2200-SEJ (3-glycidoxypropyltrimethoxysilane surface-treated silicon dioxide, average particle size 0.6 μm, manufactured by Admatex) • SE1050-SEO (3-glycidoxypropyltrimethoxysilane surface-treated silicon dioxide, average particle size 0.3 μm, manufactured by Admatex) • SE5200-SEE (3-glycidoxypropyltrimethoxysilane surface-treated silicon dioxide, average particle size 2.0 μm, manufactured by Admatex) • SE2300 (Silicon dioxide - no surface treatment, average particle size 0.6 μm, manufactured by Admatex) • SE2200-SME (3-methacryloxypropyltrimethoxysilane surface-treated silicon dioxide, average particle size 0.6 μm, manufactured by Admatex)

[0075] Surface treatment agent for large diameter fillers • g1: 3-Glycidoxypropyltrimethoxysilane • g2: 3-methacryloxypropyltrimethoxysilane

[0076] (C2) Small diameter filler • YA010A (average particle size 10nm, manufactured by Admatex Corporation) • YC100C (average particle size 100nm, manufactured by Admatex)

[0077] (D) Ionic compounds d1: 1-Butyl-1-methylpyrrolidinium=bis(trifluoromethylsulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 027-15441, CAS No. 223437-11-4, Melting point: -15℃, Structural formula d1 below)

[0078] [ka]

[0079] d2: Tributyldodecylphosphonium=bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 205-19961, CAS No. 1002754-39-3, Melting point: -16℃, Structural formula d2 below)

[0080] [ka]

[0081] d3: 1-Hexyl-4-methylpyridinium=bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 084-10131, CAS No. 870296-13-2, Melting point: 12℃, Structural formula d3 below)

[0082] [ka]

[0083] d4: Trimethylpropylammonium bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 201-19941, CAS No. 268536-05-6, Melting point: 19°C, Structural formula d4 below)

[0084] [ka]

[0085] d5: 4-(2-ethoxyethyl)-4-methylmorpholinium=bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 053-09071, CAS No. 663628-48-6, Melting point: Unknown (However, it has been confirmed that the ionic compound of structural formula d5 below is liquid at room temperature), structural formula d5 below)

[0086] [ka]

[0087] d6: Methyltrioctylammonium bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 136-17481, CAS No. 375395-33-8, Melting point: -70°C, Structural formula d6 below)

[0088] [ka]

[0089] d7: Tributylmethylammonium bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 352-27751, CAS No. 405514-94-5, Melting point: Unknown (however, it has been confirmed that the ionic compound of structural formula d7 below is liquid at room temperature)). the below described Structural formula d7)

[0090] [ka]

[0091] d8: 1-Butyl-3-dodecylimidazolium=bis(trifluoromethanesulfonyl)imide (Fujifilm Wako Pure Chemical Industries: 022-18791, CAS No. 1612842-42-8, Melting point: Unknown (However, it has been confirmed that the ionic compound of structural formula d8 below is liquid at room temperature), structural formula d8 below)

[0092] [ka]

[0093] d9: Methyltrioctylammonium tosylate (melting point: 78°C, structural formula d9 below)

[0094] [ka]

[0095] d10: Tributyldodecylphosphonium tosylate (Melting point: Unknown (However, it has been confirmed that the organic salt of structural formula d10 below is liquid at room temperature), structural formula d10 below)

[0096] [ka]

[0097] d11: Tributyldodecylphosphonium=dodecylbenzenesulfonate (Melting point: Unknown (However, it has been confirmed that the organic salt of structural formula d11 below is liquid at room temperature), structural formula d11 below)

[0098] [ka] Structural formula d11

[0099] d12: N-Oleyl-N,N-di(2-hydroxyethyl)-N-methylammonium=bis(trifluoromethanesulfonyl)imide (Melting point: Unknown (However, it has been confirmed that the ionic compound of structural formula d12 below is liquid at room temperature), structural formula d12 below)

[0100] [ka]

[0101] d13: Tributyl[3-(trimethoxysilyl)propyl]phosphonium=1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]methanesulfonamide (Melting point: Unknown (However, it has been confirmed that the ionic compound of structural formula d13 below is liquid at room temperature, see structural formula d13 below))

[0102] [ka]

[0103] d14: Methyltrioctylammoniumimide disulfuryl fluoride (Melting point: Unknown (However, it has been confirmed that the ionic compound with structural formula d14 below is liquid at room temperature), structural formula d14 below)

[0104] [ka]

[0105] d15: Tetrabutylammonium hexafluorophosphorate (Fujifilm Wako Pure Chemical Industries: 352-41372, CAS No. 3109-63-5, Melting point: 242°C, Structural formula d15 below)

[0106] [ka]

[0107] d16: Methyltrioctylammonium hexafluorophosphate (Fujifilm Wako Pure Chemical Industries: 133-17491, CAS No. 569652-37-5, Melting point: 78°C, Structural formula d16 below)

[0108] [ka]

[0109] (E) Various additives e1:MX-137 (Core-shell type butadiene rubber particles, manufactured by Kaneka Corporation) e2:MX-965 (Core-shell type silicone) system (Rubber particles, manufactured by Kaneka Corporation) e3:2P4MZ (2-phenyl-4-methylimidazole, curing accelerator, manufactured by Shikoku Chemicals Co., Ltd.) e4:KBM403 (3-glycidoxypropyltrimethoxysilane, coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd.) e5:CG1400 (Dicyandiamide, curing accelerator, manufactured by Air Products and Chemicals) e6:TPP (triphenylphosphine, viscosity inhibitor, manufactured by Hokko Chemical Industry Co., Ltd.)

[0110] 3. Evaluation Results The viscosity, thixotropy index, and injectability of the epoxy resin compositions of each example and comparative example, as well as the filler distribution index and cured appearance of the epoxy resin compositions of each example and comparative example, were measured or evaluated according to the procedure described below. The results are shown in Tables 1 to 6.

[0111] (viscosity) Viscosity was measured for the epoxy resin composition immediately after preparation using a Brookfield HBDV-1 rotational viscometer (using a SC4-14 spindle) under the conditions of a liquid temperature of 25°C and 5 rpm.

[0112] (Thixotropy Index (TI)) The thixotropy index (TI) of the epoxy resin composition was calculated using the two viscosities obtained in the viscosity measurement described above, as the ratio of the viscosity measured at 5 rpm to the viscosity measured at 50 rpm.

[0113] (Injectable) Test specimens were prepared by creating a 20 μm or 50 μm gap on an organic substrate (FR-4 substrate) and fixing a glass plate in place of a semiconductor element. Next, with this test specimen placed on a hot plate set to a temperature of 110°C, an epoxy resin composition was applied to one end of the glass plate, thereby injecting the epoxy resin composition into the gap formed between the organic substrate and the glass plate. At this time, the time it took for the injection distance of the epoxy resin composition to reach 20 mm, with the end of the glass plate coated with the epoxy resin composition being set as 0 mm, was measured. This procedure was performed twice, and the average of the two measured values ​​was determined as the injection time.

[0114] (Filler distribution index) A semiconductor device was fabricated using an epoxy resin composition and flip-chip mounting. For the fabrication of the semiconductor device, a substrate was used, equipped with solder bumps made of a tin alloy containing tin as the main component as substrate-side electrodes 10, and a semiconductor device was equipped with element-side electrodes 20 made of copper pillars. The semiconductor device was then fabricated by sequentially performing connection, filling, and curing processes. The curing conditions in the curing process were 150°C for 120 minutes.

[0115] Next, the fabricated semiconductor device with a chip size of 10 mm x 10 mm was cut using a slicer (BUEHLER, ISOMET 4000), and the cut surface was polished sequentially using 240, 800, and 1200 grit abrasive paper to obtain a sample for SEM observation with the central part of the semiconductor device's cut surface exposed. Then, by imaging the cut surface of the sample for SEM observation using FE-SEM, an enlarged SEM image of the vicinity of the electrode connection part 30, as exemplified in Figure 1, was obtained. Based on this SEM image, image processing was performed according to the procedure described above to obtain the filler occupancy rate a in region Ra and the filler occupancy rate b in region Rb. Subsequently, these values ​​a and b were substituted into equation (1) to calculate the filler distribution index. A filler distribution index of 100 ± 50 was considered good.

[0116] (Appearance of cured product) Test specimens were obtained by curing the epoxy resin composition at 150°C for 120 minutes. Next, the surface of these test specimens was visually inspected to see whether or not the ionic compound had seeped out onto the surface. The evaluation criteria were as follows. A: No leaching of ionic compounds was observed. B: Leakage of ionic compounds was observed.

[0117] [Table 1]

[0118] [Table 2]

[0119] [Table 3]

[0120] [Table 4]

[0121] [Table 5]

[0122] [Table 6] [Explanation of Symbols]

[0123] 10 Substrate-side electrodes 20 Element-side electrodes 30 Electrode connection section 40 Sealing material< / ii> < / ii>

Claims

1. (A) epoxy resin, (B) curing agent, (C) filler, and (D) an ionic compound in which at least one of the cation or anion is an organic substance. Includes, The aforementioned ionic compound, (D-1) 1-butyl-1-methylpyrrolidinium=bis(trifluoromethylsulfonyl)imide (D-2) Tributyldodecylphosphonium=bis(trifluoromethanesulfonyl)imide (D-3) 1-hexyl-4-methylpyridinium=bis(trifluoromethanesulfonyl)imide (D-4) Trimethylpropylammonium = bis(trifluoromethanesulfonyl)imide, (D-5) 4-(2-ethoxyethyl)-4-methylmorpholinium=bis(trifluoromethanesulfonyl)imide (D-6) Methyltrioctylammonium = bis(trifluoromethanesulfonyl)imide, (D-7) Tributylmethylammonium = bis(trifluoromethanesulfonyl)imide, (D-8) 1-butyl-3-dodecylimidazolium=bis(trifluoromethanesulfonyl)imide (D-9) Methyltrioctylammonium tosylate, (D-10) Tributyldodecylphosphonium tosylate, (D-11) Tributyldodecylphosphonium=dodecylbenzenesulfonate, (D-12) N-oleyl-N,N-di(2-hydroxyethyl)-N-methylammonium = bis(trifluoromethanesulfonyl)imide (D-13) Tributyl[3-(trimethoxysilyl)propyl]phosphonium=1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]methanesulfonamide, (D-14) Methyltrioctylammoniumimidodisulfurylfluoride, (D-15) Tetrabutylammonium hexafluorophosphate, and, (D-16) Methyltrioctylammonium hexafluorophosphate An epoxy resin composition characterized by containing at least one selected from the group consisting of the following.

2. The epoxy resin composition according to claim 1, characterized in that the content ratio of the (D) ionic compound is 0.0001% by mass to 3.1% by mass with respect to the total amount of the epoxy resin composition.

3. The epoxy resin composition according to claim 1 or 2, characterized in that the content ratio of the (D) ionic compound is 0.001% by mass or more and 1.2% by mass or less with respect to the total amount of the epoxy resin composition.

4. The epoxy resin composition according to claim 1 or 2, characterized in that the epoxy resin (A) comprises a liquid epoxy resin.

5. The epoxy resin composition according to claim 1 or 2, characterized in that the epoxy resin (A) comprises at least one selected from the group consisting of bisphenol F type epoxy resin, bisphenol A type epoxy resin, biphenyl type epoxy resin, aminophenol type epoxy resin, and naphthalene type epoxy resin.

6. The (C) filler includes a large-diameter filler (C1) having an average particle size of 0.2 μm or more. The epoxy resin composition according to claim 1 or 2, characterized in that the content ratio of the (C1) large-diameter filler is 35% by mass to 70% by mass with respect to the total amount of the epoxy resin composition.

7. The epoxy resin composition according to claim 6, characterized in that the average particle size of the (C1) large-diameter filler is 0.2 to 3.0 μm.

8. The (C) filler includes a (C2) small-diameter filler with an average particle size of less than 0.2 μm. The epoxy resin composition according to claim 1 or 2, characterized in that the average particle size of the (C2) small-diameter filler is 5 nm to 120 nm.

9. (E) Further containing additives, The epoxy resin composition according to claim 1 or 2, characterized in that the (E) additive comprises core-shell type rubber particles.

10. The epoxy resin composition according to claim 1 or 2, characterized in that it is used as a encapsulant for semiconductor devices.

11. A semiconductor device comprising a substrate, a semiconductor element disposed on the substrate, and a cured product of the epoxy resin composition according to claim 1 or 2 that seals the gap between the semiconductor element and the substrate.

12. A method for manufacturing a semiconductor device, comprising the steps of: filling the gap between a substrate and a semiconductor element disposed on the substrate with the epoxy resin composition described in claim 1 or claim 2; and curing the epoxy resin composition.

Images