Resin composition for sealing and semiconductor device

Abstract

The present disclosure addresses the problem of providing a resin composition for sealing in which voids are unlikely to form. This resin composition for sealing contains a heat-resistant imidazole having: a specific structure, which is represented by formula (1), in the molecule; a liquid epoxy resin; a liquid phenol resin; an inorganic filler; and a reducing component. The ratios of the heat-resistant imidazole, inorganic filler, reducing component relative to the entirety of the resin composition for sealing are 0.1-3 mass%, 45-65 mass%, and 0.5-4 mass%, respectively.

Description

Encapsulating resin composition and semiconductor device

[0001] This disclosure relates to a encapsulating resin composition and a semiconductor device, and more particularly to a encapsulating resin composition and a semiconductor device containing an epoxy resin.

[0002] Patent Document 1 discloses a pre-supplied liquid semiconductor encapsulation resin composition. This liquid semiconductor encapsulation resin composition is characterized by comprising (A) a liquid epoxy resin, (B) an epoxy resin of a specific structure, (C) a liquid acid anhydride curing agent, and (D) a microcapsule-type curing accelerator. This liquid semiconductor encapsulation resin composition is said to be excellent in handling narrow pitches, capable of curing in a short time, and capable of suppressing voids between semiconductor chips and substrates in a short time.

[0003] However, the liquid semiconductor encapsulating resin composition described in Patent Document 1 is still insufficient in terms of its resistance to void formation, and there is room for improvement.

[0004] Patent No. 5723665

[0005] The object of this disclosure is to provide a sealing resin composition that is less prone to void formation, and a semiconductor device.

[0006] A sealing resin composition according to one aspect of the present disclosure is a sealing resin composition containing a heat-resistant imidazole having a specific structure represented by the following formula (1) in its molecule, a liquid epoxy resin, a liquid phenolic resin, an inorganic filler, and a reducing component, wherein the proportion of the heat-resistant imidazole to the whole sealing resin composition is 0.1% by mass or more and 3% by mass or less, the inorganic filler is 45% by mass or more and 65% by mass or less, and the reducing component is 0.5% by mass or more and 4% by mass or less.

[0007]

[0008] In formula (1), * indicates a site that binds to a portion of the heat-resistant imidazole other than the specific structure represented by formula (1).

[0009] A semiconductor device according to one aspect of the present disclosure comprises a semiconductor element in which the void around the connection portion is sealed with the sealing resin composition.

[0010] Figure 1 is a schematic plan view showing the asterisk shape formed in the method for evaluating dispensability.

[0011] 1. Overview The encapsulation resin composition according to this embodiment will be described below.

[0012] In order to solve the above-mentioned problems, the inventors diligently studied encapsulating resin compositions and found that the above-mentioned problems could be solved by using components with specific physical properties and by setting the proportion of each component within a specific range, thus completing this disclosure.

[0013] The sealing resin composition according to this embodiment (hereinafter also referred to as composition (X)) contains a heat-resistant imidazole having a specific structure represented by the following formula (1) in its molecule (hereinafter also referred to as specific imidazole (A)), a liquid epoxy resin (hereinafter also referred to as liquid epoxy resin (B)), a liquid phenol resin (hereinafter also referred to as liquid phenol resin (C)), an inorganic filler (hereinafter also referred to as inorganic filler (D)), and a reducing component (hereinafter also referred to as reducing component (E)). The proportions of specific imidazole (A) to the whole composition (X) are 0.1% by mass or more and 3% by mass or less, inorganic filler (D) is 45% by mass or more and 65% by mass or less, and reducing component (E) is 0.5% by mass or more and 4% by mass or less.

[0014] Composition (X) exhibits the effect of being less prone to void formation, i.e., having excellent void suppression properties. In addition to this void suppression effect, composition (X) also exhibits the properties required for encapsulating resin compositions, namely "dispensability" which allows it to be dispensed in a desired shape from a dispenser, "shape retention" which allows it to maintain the dispensed shape over time, "curing timing" which indicates the appropriateness of the heat generation behavior of composition (X), "chip connectivity" which indicates good electrical connection in the formed mounting body, and "pot life" which indicates storage stability.

[0015] The reason why composition (X) achieves the above effects by having the above configuration is not entirely clear, but it can be inferred, for example, as follows. Composition (X) uses a heat-resistant imidazole (A) as the specific imidazole (A), which has a specific structure represented by formula (1), is poorly compatible with liquid epoxy resin (B) and liquid phenolic resin (C), has a small thermal weight loss rate at 250°C, and is resistant to volatilization and thermal decomposition. By setting the proportion of this specific imidazole (A) within a specific range, the curing timing can be made appropriate and the chip connectability can be improved. Furthermore, by using the specific imidazole (A), liquid epoxy resin (B), and liquid phenolic resin (C), and setting the proportion of inorganic filler (D) within a specific range, the viscosity can be reduced, thereby improving dispensability and shape retention. Composition (X) uses a specific imidazole (A), a liquid epoxy resin (B), and a liquid phenolic resin (C), and by keeping the proportions of the inorganic filler (D) and reducing component (E) below a specific value, it is believed that the amount of gas generated can be reduced, thereby improving void suppression. Furthermore, by using a specific imidazole (A) and keeping the proportion of the reducing component (E) below a specific value, it is believed that the pot life can be improved. As described above, composition (X) is considered to have excellent void suppression, and in addition, excellent dispensability, shape retention, curing timing, tip connectability, and pot life.

[0016] Thus, according to this disclosure, it is possible to provide a sealing resin composition that is less prone to void formation, and a semiconductor device.

[0017] 2. Details <Sealing Resin Composition> Composition (X) contains a specific imidazole (A), a liquid epoxy resin (B), a liquid phenolic resin (C), an inorganic filler (D), and a reducing component (E). Composition (X) may further contain other components other than components (A) to (E) as long as the effects of the present disclosure are not impaired.

[0018] In addition to void suppression properties, the composition (X) is excellent in dispensability, shape retention property, curing timing, chip connectivity and pot life (hereinafter also referred to as various properties of the composition (X)). Each component will be described below.

[0019] [Specific Imidazole] Imidazole is a compound having an imidazole ring, which can promote the reaction between epoxy groups contained in a liquid epoxy resin (B) and the addition reaction of phenolic OH groups contained in a liquid phenolic resin (C) to epoxy groups, and is a component that can impart thermosetting properties to the composition (X).

[0020] The specific imidazole (A) is a heat-resistant imidazole having a specific structure represented by the following formula (1) in the molecule.

[0021]

[0022] In the above formula (1), * indicates a site that binds to a portion other than the specific structure represented by formula (1) in the specific imidazole (A).

[0023] The term "heat-resistant imidazole" refers to an imidazole having a thermogravimetric weight loss rate of 10% or less at 250°C, which is measured using a thermogravimetric differential thermal analyzer (for example, "TG / DTA7300" manufactured by Hitachi High-Tech Science Corporation) under a nitrogen stream of 200 mL / min, in a temperature range from 30°C to 350°C, at a temperature increase rate of 10°C / min.

[0024] The thermogravimetric weight loss rate of the specific imidazole (A) at 250°C is preferably 9% or less, more preferably 5% or less, and still more preferably 2% or less.

[0025] The specific structure in the specific imidazole (A) is the structure of 2,4-diamino-1,3,5-triazine as represented by the above formula (1). By having this specific structure, the specific imidazole (A) becomes difficult to be compatible with organic resins such as the liquid epoxy resin (B) and the liquid phenolic resin (C).

[0026] Examples of moieties other than the specific structure in the specific imidazole (A) include substituted or unsubstituted imidazolyl groups, and alkanediyl groups to which a substituted or unsubstituted imidazolyl group is bonded.

[0027] Examples of substituents for the imidazolyl group include alkyl groups having 1 to 20 carbon atoms, and alkyl groups having 1 to 13 carbon atoms are preferable. The number of carbon atoms of the alkanediyl group is, for example, 1 or more and 5 or less, preferably 2 or more and 4 or less, and more preferably 2 carbon atoms.

[0028] The specific imidazole (A) preferably comprises a molecular structure represented by the following formula (2). That is, the specific imidazole (A) may be a compound having this molecular structure, or may be a compound in which a substituent is bonded to this molecular structure. In this case, various properties of the composition (X) can be further improved.

[0029]

[0030] In the above formula (2), R １ and R ２ each independently represent a hydrogen atom or an alkyl group having 1 to 13 carbon atoms.

[0031] R １ and R ２ are preferably a hydrogen atom, a methyl group, an ethyl group or an undecyl group.

[0032] Examples of the specific imidazole (A) include 2,4-diamino-6-[2'-(methylimidazolyl-1')ethyl]-s-triazine, 2,4-diamino-6-[2'-(undecylimidazolyl-1')ethyl]-s-triazine, 2,4-diamino-6-[2'-(ethylimidazolyl-1')ethyl]-s-triazine, and the like.

[0033] Examples of commercially available products of the specific imidazole (A) include 2MZA, C11Z-A, and 2E4MZ-A (all manufactured by Shikoku Kasei Kogyo Co., Ltd.), and the like.

[0034] It is important that the proportion of the specific imidazole (A) is 0.1% by mass or more and 3% by mass or less of the total composition (X). If this proportion is outside the above range, the curing timing of composition (X) will be inappropriate and properties such as chip connectivity will deteriorate. The proportion of the specific imidazole (A) is preferably 0.2% by mass or more, and more preferably 0.4% by mass or more. The above proportion is preferably 2.8% by mass or less, and more preferably 2.6% by mass or less.

[0035] The amount of specific imidazole (A) is preferably 0.2 parts by mass or more and 8 parts by mass or less, more preferably 0.5 parts by mass or more and 7.5 parts by mass or less, and even more preferably 1.4 parts by mass or more and 7 parts by mass or less, based on 100 parts by mass of the total of liquid epoxy resin (B) and liquid phenolic resin (C).

[0036] [Liquid Epoxy Resin] Epoxy resin is a compound having one or more epoxy groups in one molecule, and has the property of hardening when heated, and is a component that can impart thermosetting properties to composition (X). As the epoxy resin, a compound having two or more epoxy groups in one molecule is preferred. In this case, the thermosetting properties of composition (X) can be further improved.

[0037] "Liquid epoxy resin" refers to epoxy resin that is liquid at room temperature (25°C), and specifically epoxy resin whose viscosity, measured at 25°C and atmospheric pressure, is 2000 Pa·s or less.

[0038] The liquid epoxy resin (B) may consist only of components that are liquid at 25°C, or it may consist of components that are liquid at 25°C and components that are not liquid at 25°C.

[0039] Examples of the liquid epoxy resin (B) include bisphenol-type epoxy resins, hydrogenated bisphenol-type epoxy resins, biphenyl-type epoxy resins, naphthalene ring-containing epoxy resins, alicyclic epoxy resins, phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, triphenylmethane-type epoxy resins, aliphatic epoxy resins, triglycidyl isocyanurate, glycidyl group-containing silicone resins, and glycidylamine-type epoxy resins. Among these, bisphenol-type epoxy resins or glycidylamine-type epoxy resins are preferable.

[0040] Examples of the bisphenol-type epoxy resin include bisphenol A-type epoxy resin and bisphenol F-type epoxy resin.

[0041] The liquid epoxy resin (B) preferably contains at least one of structures represented by the following formula (3) and the following formula (4), for example. The following formula (3) is a bisphenol-type epoxy resin, and the following formula (4) is a glycidylamine-type epoxy resin. In these cases, various properties of the composition (X) can be further improved.

[0042]

[0043] In the above formula (3), R ３ , R ４ , R ５ and R ６ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. n is an integer of 0 or more.

[0044]

[0045] In the above formula (4), R ７ represents an alkyl group having 1 to 3 carbon atoms or a glycidyloxy group.

[0046] As for R ３ , R ４ , R ５ and R ６ in the above formula (3), a hydrogen atom or a methyl group is preferable. As for n, 0 or 1 is preferable.

[0047] As for R ７A methyl group or a glycidyloxy group is preferred.

[0048] The epoxy group equivalent of the liquid epoxy resin (B) is preferably in the range of 50 g / molL to 500 g / molL. "Epoxy group equivalent" means the molecular mass (g) per 1 molL of epoxy group, and can be measured by a method in accordance with JIS-K-7236:2001.

[0049] Examples of commercially available liquid epoxy resins (B) include, as bisphenol A type epoxy resins, YD-8125 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), EPICLON840, EPICLON840-S, and EPICLON850 (all manufactured by DIC Corporation), as well as bisphenol F type epoxy resins, YD-8170 (manufactured by Nippon Steel Chemical & Material Co., Ltd.) and EPICLON-EXA830CRP (manufactured by DIC Corporation), and as glycidylamine type epoxy resins, EP-3950L and EP-3980S (both manufactured by ADEKA Corporation) and jER630 (manufactured by Mitsubishi Chemical Corporation).

[0050] The proportion of liquid epoxy resin (B) is preferably 25% by mass or more, and more preferably 28% by mass or more, relative to the total composition (X). The above proportion is preferably 45% by mass or less, and more preferably 42% by mass or less. In these cases, the various properties of composition (X) can be further improved.

[0051] The proportion of liquid epoxy resin (B) is preferably 70% by mass or more and 90% by mass or less, and more preferably 74% by mass or more and 85% by mass or less, relative to the total of liquid epoxy resin (B) and liquid phenolic resin (C).

[0052] [Liquid Phenolic Resin] The phenolic resin is a compound having one or more phenolic OH groups in one molecule, and acts as a curing agent that reacts with the epoxy resin upon heating, thereby imparting thermosetting properties to composition (X). A compound having two or more phenolic OH groups in one molecule is preferred as the phenolic resin. In this case, the thermosetting properties of composition (X) can be further improved.

[0053] "Liquid phenolic resin" refers to phenolic resin that is liquid at room temperature (25°C), and specifically means phenolic resin whose viscosity, measured at 25°C and atmospheric pressure, is 2000 Pa·s or less.

[0054] The liquid phenolic resin (C) may consist only of components that are liquid at 25°C, or it may consist of components that are liquid at 25°C and components that are not liquid at 25°C. A phenolic resin that is solid at 25°C can be used by dissolving or dispersing it in a phenolic resin that is liquid at 25°C.

[0055] A phenol novolac resin is preferred as the liquid phenol resin (C). The liquid phenol resin (C) may consist solely of a phenol novolac resin, or it may consist of a phenol novolac resin and a resin other than a phenol novolac resin.

[0056] As the phenol novolac resin, a resin represented by the following formula (5) is preferred. In this case, the properties of composition (X) can be further improved.

[0057]

[0058] In the above formula (5), R ８ , R ９ , R １０ , R １１ and R １２ Each of these independently represents a hydrogen atom or an allyl group. n is an integer from 1 to 3. Multiple R ８ , R ９ , R １０ , R １１ and R １２ They may be the same or different. ８ , R ９ , R １０ , R １１ and R １２ At least one of them is an allyl group.

[0059] The weight-average molecular weight (Mw) of the liquid phenolic resin (C) is preferably 200 or more and 10,000 or less, more preferably 225 or more and 8,000 or less, and even more preferably 250 or more and 6,000 or less. In this case, composition (X) can improve the coverage ratio, which is the ratio of the height of the reinforced part to the height of the bump. The Mw of the liquid phenolic resin (C) refers to the polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0060] The OH group equivalent of the liquid phenolic resin (C) is preferably 50 g / mol or more and 1500 g / mol or less, more preferably 50 g / mol or more and 1000 g / mol or less, and even more preferably 100 g / mol or more and 500 g / mol or less. In this case, the dispensability of composition (X) can be further improved. "OH group equivalent" means the molecular mass (g) per 1 mol of phenolic OH groups, and can be measured by a method in accordance with JIS-K-0070.

[0061] The proportion of liquid phenolic resin (C) is preferably 5% by mass or more and 15% by mass or less, and more preferably 7% by mass or more and 12% by mass or less, relative to the total composition (X).

[0062] The amount of liquid phenolic resin (C) is preferably 20 parts by mass or more and 30 parts by mass or less, and more preferably 25 parts by mass or more and 28 parts by mass or less, per 100 parts by mass of liquid epoxy resin (B).

[0063] [Inorganic Filler] Inorganic filler (D) refers to a filler made of an inorganic substance. Composition (X) has excellent shape retention properties by containing inorganic filler (D).

[0064] Examples of materials for the inorganic filler (D) include glass, silicon dioxide (silica), aluminum oxide (alumina), titanium oxide (titania), magnesium oxide (magnesia), carbon black, mica, and barium sulfate. The inorganic filler (D) may be used alone or in a mixture of two or more types.

[0065] The inorganic filler (D) may be a composite oxide containing two or more metal oxides. This composite oxide may simply be a mixture of two or more metal oxides, or it may be a mixture in which the metal oxides are chemically bonded together and cannot be separated. Examples of such composite oxides include a composite oxide made of silicon dioxide and titanium oxide, a composite oxide made of silicon dioxide and aluminum oxide, a composite oxide made of boron oxide and aluminum oxide, and a composite oxide made of silicon dioxide, aluminum oxide and magnesium oxide.

[0066] The shape of the inorganic filler (D) is not particularly limited and can be in the form of crushed, needle-shaped, flaky, or spherical shapes. From the viewpoint of dispersibility and viscosity control in composition (X), it is preferable to use spherical fillers.

[0067] The average particle diameter of the inorganic filler (D) is not particularly limited, as long as it is smaller than the gap between the semiconductor chip and the substrate when flip-chip connected. From the viewpoint of packing density and viscosity control, the average particle diameter of the inorganic filler (D) is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less. The average particle diameter of the inorganic filler (D) is, for example, 0.1 μm or more. This average particle diameter is the value measured as the particle diameter (D50) when the cumulative value from the smallest diameter side reaches 50% in the volume-based particle size distribution measured by a laser diffraction scattering particle size distribution analyzer.

[0068] Furthermore, in order to adjust the viscosity of composition (X) and the physical properties of the cured product, two or more inorganic fillers (D) with different average particle sizes may be used in combination.

[0069] It is important that the proportion of inorganic filler (D) is 45% by mass or more and 65% by mass or less of the total composition (X). If this proportion is outside the above range, properties such as void suppression, tip connectivity, and shape retention will deteriorate. This proportion is preferably 47% by mass or more and 62% by mass or less, and more preferably 48% by mass or more and 60% by mass or less.

[0070] The amount of inorganic filler (D) is preferably 110 parts by mass or more and 170 parts by mass or less, and more preferably 120 parts by mass or more and 150 parts by mass or less, based on 100 parts by mass of the total of liquid epoxy resin (B) and liquid phenolic resin (C).

[0071] [Reducing component] The reducing component (E) has reducing properties and the function of removing metal oxide films, and is a component that can impart a metal oxide film removal effect to composition (X). "Metal oxide film removal effect" means the effect of removing oxide films formed on the metal surface to which the solder is applied, and the effect of reducing the surface tension of the molten solder and increasing the wettability of the solder to the joined metal surface.

[0072] The reducing component (E) preferably contains at least one of the following: an organic acid (hereinafter also called organic acid (D1)) having a carboxyl group equivalent of 40 g / molL or more and 400 g / molL or less and a melting point of 220°C or less, and an amine (hereinafter also called amine (D2)) having a nitrogen atom equivalent of 10 g / molL or more and 300 g / molL or less and a melting point of 220°C or less. The amine refers to an amine used as a flux, and includes, for example, amine salts, alkanolamines, guanidine, etc.

[0073] The reducing component (E) has a melting point of 220°C or lower, so even when using solder with a melting point of around 200°C or above 200°C, it can remove the oxide film from the solder before melting the solder. Here, the "carboxyl group equivalent" of the organic acid (D1) means the molecular mass (g) of the organic acid per 1 molar of carboxyl group. Also, the "nitrogen atom equivalent" of the amine (D2) means the molecular mass (g) of the amine per 1 molar of nitrogen atoms of the amine (D2).

[0074] Examples of organic acids (D1) include rosin component materials, adipic acid, glutaric acid, succinic acid, malonic acid, citric acid, corticic acid, sebacic acid, and pimelic acid. A commercially available organic acid (D1) is Tsunodaimu 395 (dimer acid: 94% by mass) manufactured by Tsukuno Foods Co., Ltd.

[0075] The organic acid (D1) preferably includes succinic acid (carboxyl group equivalent: 59 g / mol), glutaric acid (carboxyl group equivalent: 66 g / mol), adipic acid (carboxyl group equivalent: 73 g / mol), corticic acid (carboxyl group equivalent: 87 g / mol), sebacic acid (carboxyl group equivalent: 101 g / mol), or hornodigm 395 (carboxyl group equivalent: 288 g / mol).

[0076] The amine (D2) preferably includes, in particular, diethanolamine (nitrogen atom equivalent: 105 g / mol), N-phenyldiethanolamine (nitrogen atom equivalent: 181 g / mol), triethanolamine (TEA) (nitrogen atom equivalent: 149 g / mol), triisopropanolamine (nitrogen atom equivalent: 191 g / mol), 1,3-diphenylguanidine (nitrogen atom equivalent: 70 g / mol), or 1,3-di-o-tolylguanidine (nitrogen atom equivalent: 80 g / mol).

[0077] The reducing component (E) may include other components besides the organic acid (D1) and amine (D2), such as organic acids and amines with a melting point exceeding 220°C.

[0078] It is important that the proportion of the reducing component (E) is between 0.5% by mass and 4% by mass of the total composition (X). If this proportion is outside the above range, the void suppression performance deteriorates. This proportion is preferably between 0.6% by mass and 3.5% by mass, and more preferably between 0.7% by mass and 3% by mass.

[0079] [Other components] Other components include, for example, solvents, coupling agents, mold release agents, flame retardants, flame retardant aids, ion trapping agents, pigments, colorants, stress reducers, tackifiers, silicone flexible agents, etc.

[0080] Composition (X) typically does not contain a solvent. Because composition (X) does not contain a solvent, a drying process after application becomes unnecessary.

[0081] If composition (X) contains other components, the proportion of these other components is, for example, 1% by mass or less relative to the entire composition (X).

[0082] Composition (X) can be prepared by blending and mixing, for example, a specific imidazole (A), a liquid epoxy resin (B), a liquid phenolic resin (C), an inorganic filler (D), a reducing component (E), and other components as needed.

[0083] Since composition (X) has excellent properties such as void suppression, it can be suitably used, for example, to seal voids around connection parts in semiconductor devices in which semiconductor elements and wiring substrates are electrically connected via connection parts, thereby improving the performance of the semiconductor device.

[0084] Furthermore, as described above, composition (X) is excellent in various properties such as dispensability, shape retention, curing timing, and chip connectivity, in addition to void suppression. Therefore, it can be suitably used as a pre-supplied encapsulating resin composition, that is, in a process in which the encapsulating resin composition is applied to a wiring board, interposer, etc., and then semiconductor elements are thermocompressed to perform encapsulation.

[0085] <Semiconductor device> The semiconductor device of this embodiment (hereinafter also referred to as semiconductor device (Y)) comprises a semiconductor element in which the air gap around the connection portion is sealed with, for example, the above-described composition (X).

[0086] In other words, the semiconductor device (Y) is a semiconductor device in which a semiconductor element and a wiring substrate are electrically connected via a connection portion, and the air gap around this connection portion is sealed with composition (X) and includes a semiconductor element.

[0087] This semiconductor device (Y) is obtained by sealing any voids that may occur around a connection point during the manufacturing process of a semiconductor device in which a semiconductor element and a wiring substrate are electrically connected via a connection point, using composition (X).

[0088] The above-described composition (X) is excellent in various properties, including void suppression, dispensability, shape retention, curing timing, chip connectivity, and pot life. By using it to seal around the connection part, a semiconductor device (Y) can be obtained in which voids are reduced and excellent performance can be obtained.

[0089] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0090] <Preparation of sealing resin composition> The sealing resin compositions of Examples 1 to 11 and Comparative Examples 1 to 11 were obtained by blending and mixing the components of the types and parts by mass shown in Tables 1 and 2 below. Details of each component are as follows.

[0091] (Specific Imidazole (A)) (A1-A3 and a1-a3 are manufactured by Shikoku Chemicals Co., Ltd.) - A1: "2MZ-A" (2,4-diamino-6-[2'-(methylimidazolyl-1')ethyl]-s-triazine, thermal weight loss rate at 250°C: 1.5%) - A2: "C11Z-A" (2,4-diamino-6-[2'-(undecylimidazolyl-1')ethyl]-s-triazine, thermal weight loss rate at 250°C: 1.7%) - A3: "2E4MZ-A" (2,4-diamino-6-[2'-(ethylimidazolyl-1')ethyl]-s-triazine, thermal weight loss rate at 250°C: 8.1%) -a1: "2MA-OK" (2,4-diamino-6-[2'-(methylimidazolyl-1')ethyl]-s-triazine isocyanurate adduct, thermal weight loss at 250°C: 11.0%) -a2: "2P4MZ" (2-phenyl-4-methylimidazole, thermal weight loss at 250°C: 17.3%) -a3: "2PHZ" (2-phenyl-4,5-dihydroxymethylimidazole, thermal weight loss at 250°C: 13.2%)

[0092] (Liquid epoxy resin (B)) - B1: "YDF-8170" manufactured by Nippon Steel Chemical & Material Co., Ltd. (Liquid at 25°C, bisphenol F type epoxy resin, R in formula (3) above) ３ ~R ６ (All are methyl groups, n=0, epoxy group equivalent: 173 g / mol) -B2: "YD-8125" manufactured by Nippon Steel Chemical & Material Co., Ltd. (liquid at 25°C, bisphenol A type epoxy resin, in formula (3) above, R ３ ~R ６(All are hydrogen atoms, n=0, epoxy group equivalent: 170 g / mol) - B3: "EP-3950L" manufactured by ADEKA Corporation (liquid at 25°C, glycidylamine type epoxy resin, in formula (4) above, R ７ (Glycidyloxy group, epoxy group equivalent: 95 g / mol) - b1: "HP-7200" manufactured by DIC Corporation (solid at 25°C, dicyclopentadiene type epoxy resin, epoxy group equivalent: 280-292 g / mol)

[0093] (Liquid phenolic resin (C)) - C1: "MEH-8000H" manufactured by Meiwa Kasei Co., Ltd. (liquid at 25°C (1500-3500 mPa·s with an E-type viscometer (25°C)), in the above formula (5), R ８ ~R １２ (where n is a mixture of hydrogen atoms or allyl groups, n=0 to 10, OH group equivalent: 141 g / mol) - c1: "TD-2131" manufactured by DIC Corporation (solid at 25°C, OH group equivalent: 104 g / mol)

[0094] (Inorganic filler (D)) - D1: Spherical silica manufactured by Admatex (average particle size: 0.4 μm)

[0095] (Reducing component (E)) - E1: "N-phenyldiethanolamine" manufactured by Tokyo Chemical Industry Co., Ltd. - E2: "Tsunodaimu 395" manufactured by Tsukuno Foods Industry Co., Ltd. (contains 94% by mass of dimer acid)

[0096] <Evaluation> The initial viscosity, dispensability, shape retention, curing timing, tip connectivity, void suppression, and storage stability of the encapsulating resin composition prepared above were measured using the following methods.

[0097] (Initial Viscosity) The viscosity (Pa·s) of the sealing resin composition immediately after preparation was measured at 25°C and 2.5 rpm using an E-type viscometer (RE-215, manufactured by Toki Sangyo Co., Ltd.).

[0098] (Dispensability) The encapsulating resin composition was dispensed using a dispenser (ML-808GX, manufactured by Musashi Engineering Co., Ltd.) onto a silicon substrate (IP40, manufactured by Waltz Corporation) (dimensions: 10 mm long, 10 mm wide, 725 μm thick) in the form of an asterisk shape as shown in Figure 1 (the size of the asterisk shape is approximately 6 mm long and 6 mm wide). The appearance of the encapsulating resin composition was observed to determine the dispensability. Dispensability was evaluated as A (good) if the encapsulating resin composition was not interrupted, and as B (poor) if the encapsulating resin composition was interrupted.

[0099] (Shape Retention) Shape retention was determined by observing the change in shape over time after dispensing the sealing resin composition, as described in the evaluation of "dispensability" above. Shape retention was evaluated as A (good) if the asterisk shape did not collapse after standing at 25°C for 10 minutes, and as B (poor) if the asterisk shape collapsed after standing at 25°C for 10 minutes.

[0100] (Curing Timing) The exothermic behavior of the sealing resin composition was observed using a differential scanning thermal analyzer (DSC7020, manufactured by Hitachi High-Tech Science Corporation) in a temperature range of 25°C to 350°C, with a heating rate of 10°C / min. The peak-top temperature of the DSC curve obtained from the measurement was defined as the "curing timing." The curing timing was evaluated as A (good) if the peak-top temperature was within the range of 130°C to 200°C, and as B (poor) if the peak-top temperature was below 130°C or above 200°C.

[0101] (Chip Connectivity) A silicon chip (dimensions: 7.3 mm long, 7.3 mm wide, 725 μm thick) with soldered microbumps was placed on a silicon substrate prepared in the "Dispenseability" evaluation above. The chip was connected using a flip-chip bonder (Sony's "BFC-1000"), heated from 80°C to 250°C at a heating rate of 10°C / second, and then held at 250°C for 10 seconds. The electrical resistance of the connected assembly was measured using a tester (SANWA's "LCR701") in a daisy-chain of 96 bumps to determine chip connectivity. Chip connectivity was evaluated as A (good) if the electrical resistance was 25 Ω or less, and B (poor) if the electrical resistance was greater than 25 Ω.

[0102] (Void Suppression) For the mounted material used in the evaluation of "Chip Connectivity" above, flaw detection measurements were performed using an ultrasonic flaw detection device (FSP12V manufactured by Hitachi Power Solutions Co., Ltd.) to measure the void area relative to the silicon chip area. The void ratio (%) was calculated using the formula: Void Ratio (%) = Void Area × 100 / Silicon Chip Area, and the void suppression performance was judged. Void suppression performance was evaluated as A (good) if the void ratio was 1% or less, and B (poor) if the void ratio was greater than 1%.

[0103] (Pot Life) The viscosity (Pa·s) of the sealing resin composition at 25°C and 2.5 rpm was measured after standing at 25°C for 24 hours. The viscosity increase rate (%) was calculated using the formula: Viscosity increase rate (%) = (Viscosity after 24 hours - Initial viscosity) × 100 / Initial viscosity, and the pot life was determined. The pot life was judged as A (Good) if the viscosity increase rate was 40% or less, and B (Poor) if the viscosity increase rate was more than 40%.

[0104] The evaluation results for each test are shown in the evaluation column of Tables 1 and 2 below, along with their respective measured values. In Table 2, the "-" in the shape retention column for Comparative Examples 6 to 8 indicates that the shape retention was not evaluated because the dispensability was poor.

[0105]

[0106]

[0107] As can be seen from the results in Tables 1 and 2, the sealing resin compositions of the examples exhibit excellent void suppression, as well as superior dispensability, shape retention, curing timing, tip connectivity, and pot life. The sealing resin compositions of the comparative examples are inferior in one or more of the following areas, in addition to void suppression: dispensability, shape retention, curing timing, tip connectivity, and pot life.

[0108] (Summary) As is clear from the above embodiments, the present disclosure includes the following embodiments. The encapsulating resin composition of the first embodiment contains a heat-resistant imidazole (A) having a specific structure represented by the above formula (1) in its molecule, a liquid epoxy resin (B), a liquid phenolic resin (C), an inorganic filler (D), and a reducing component (E). The proportion of the heat-resistant imidazole (A) to the whole encapsulating resin composition is 0.1% by mass or more and 3% by mass or less, the inorganic filler (D) is 45% by mass or more and 65% by mass or less, and the reducing component (E) is 0.5% by mass or more and 4% by mass or less.

[0109] According to the first embodiment, the sealing resin composition exhibits excellent void suppression properties, as well as excellent dispensability, shape retention, curing timing, tip connectivity, and pot life.

[0110] In the second embodiment of the encapsulating resin composition, the heat-resistant imidazole (A) comprises the molecular structure represented by the above formula (2), in the first embodiment.

[0111] According to the second embodiment, the encapsulating resin composition can further improve the above-mentioned properties.

[0112] In the third embodiment of the sealing resin composition, in the first or second embodiment, the liquid epoxy resin (B) includes at least one of the structures represented by formula (3) and formula (4).

[0113] According to the third aspect, the sealing resin composition can further improve the above-mentioned properties.

[0114] In the fourth embodiment of the sealing resin composition, in any one of the first to third embodiments, the liquid phenolic resin (C) includes the structure represented by the above formula (5).

[0115] According to the fourth aspect, the sealing resin composition can further improve the above-mentioned properties.

[0116] In the fifth embodiment of the sealing resin composition, in any one of the first to fourth embodiments, the proportion of liquid epoxy resin (B) is 25% by mass or more and 45% by mass or less of the total sealing resin composition.

[0117] According to the fifth aspect, the sealing resin composition can further improve the above-mentioned properties.

[0118] The sixth embodiment of the sealing resin composition is used to seal the air gap around a connection in a semiconductor device in which a semiconductor element and a wiring substrate are electrically connected via a connection, in any one of the first to fifth embodiments.

[0119] According to the sixth aspect, by using the sealing resin composition to seal voids in a semiconductor device, a semiconductor device with excellent performance can be obtained.

[0120] The semiconductor device of the seventh embodiment comprises a semiconductor element in which the void around the connection portion is sealed with a sealing resin composition according to any one of the first to sixth embodiments.

[0121] According to the seventh aspect, the semiconductor device can exhibit excellent performance by effectively sealing the air gaps around the connection portion.

Claims

1. A sealing resin composition comprising a heat-resistant imidazole having a specific structure represented by the following formula (1) in its molecule, a liquid epoxy resin, a liquid phenolic resin, an inorganic filler, and a reducing component, wherein the proportion of the heat-resistant imidazole to the entire sealing resin composition is 0.1% by mass or more and 3% by mass or less, the inorganic filler is 45% by mass or more and 65% by mass or less, and the reducing component is 0.5% by mass or more and 4% by mass or less. (In formula (1), * indicates a site that binds to a portion of the heat-resistant imidazole other than the specific structure represented by formula (1).) 2. The encapsulating resin composition according to claim 1, wherein the heat-resistant imidazole comprises a molecular structure represented by the following formula (2). (In formula (2), R １ and R ２ Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 13 carbon atoms.

3. The sealing resin composition according to claim 1, wherein the liquid epoxy resin comprises at least one of the structures represented by the following formula (3) and the following formula (4). (In formula (3), R ３ , R ４ , R ５ and R ６ Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. n is a non-negative integer. (In formula (4), R ７ (This represents an alkyl group having 1 to 3 carbon atoms, or a glycidyloxy group.) 4. The encapsulating resin composition according to claim 1, wherein the liquid phenolic resin comprises a structure represented by the following formula (5). (In formula (5), R ８ , R ９ , R １０ , R １１ and R １２ each independently represent a hydrogen atom or an allyl group. n is an integer of 1 to 3. A plurality of R ８ , R ９ , R １０ , R １１ and R １２ may be the same or different. At least one of R ８ , R ９ , R １０ , R １１ and R １２ is an allyl group.) 5. The sealing resin composition according to claim 1, wherein the proportion of the liquid epoxy resin is 25% by mass or more and 45% by mass or less with respect to the entire sealing resin composition.

6. The sealing resin composition according to claim 1, used to seal a gap around a connection in a semiconductor device in which a semiconductor element and a wiring board are electrically connected via a connection.

7. A semiconductor device comprising a semiconductor element in which the void around the connection portion is sealed with the sealing resin composition described in claim 6.

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