Resin composition for sealing and semiconductor device

Abstract

The present disclosure addresses the problem of providing a resin composition for sealing, which is unlikely to generate voids and can improve the reliability of a sealed article. This resin composition for sealing contains: one or more heat-resistant compounds that are selected from the group consisting of heat-resistant imidazoles having a specific structure represented by formula (1) in each molecule and heat-resistant metal catalysts; a liquid epoxy resin; a liquid cyanate ester resin; an inorganic filler; and a reducing component. The ratio of the heat-resistant compounds to the whole resin composition for sealing is 0.01 mass% to 3 mass% inclusive, the ratio of the inorganic filler to the whole resin composition for sealing is 40 mass% to 65 mass% inclusive, and the ratio of the reducing component to the whole resin composition for sealing is 0.5 mass% to 4 mass% inclusive.

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. Furthermore, Patent Document 1 does not examine the physical properties of the liquid semiconductor encapsulating resin composition after curing, and encapsulated materials such as semiconductor devices obtained by encapsulating with this encapsulating resin composition may have reduced reliability.

[0004] Japanese Patent Publication No. 2012-229299

[0005] The object of this disclosure is to provide a encapsulating resin composition that is less prone to void formation and can improve the reliability of the encapsulated material, and a semiconductor device.

[0006] A sealing resin composition according to one aspect of the present disclosure is a sealing resin composition comprising one or more heat-resistant compounds selected from the group consisting of heat-resistant imidazoles and heat-resistant metal catalysts having a specific structure represented by the following formula (1) in its molecule, a liquid epoxy resin, a liquid cyanate ester resin, an inorganic filler, and a reducing component, wherein the proportion of the heat-resistant compound to the entire sealing resin composition is 0.01% by mass or more and 3% by mass or less, the inorganic filler is 40% 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] As mentioned above, encapsulating resin compositions are required to be less prone to void formation and to improve the reliability of the encapsulated product. With the increasing performance of HPC (High Performance Computing) and servers, the logic semiconductors installed in them are exposed to harsh environments, with ambient temperatures exceeding 85°C. For the reliability of the encapsulating product, encapsulating resin compositions are required to maintain their physical properties, including mechanical properties, without significant degradation even at such temperatures. Specifically, for example, the glass transition temperature of the cured encapsulating resin composition must be above this temperature.

[0013] The inventors, through diligent research into encapsulating resin compositions, discovered that the above-mentioned problems could be solved by employing a specific type of resin as a component, using components with specific physical properties, and setting the proportion of each component within a specific range, and thus completed this disclosure.

[0014] The sealing resin composition according to this embodiment (hereinafter also referred to as composition (X)) contains one or more heat-resistant compounds (hereinafter also referred to as heat-resistant compound (A)) selected from the group consisting of a heat-resistant imidazole (hereinafter also referred to as specific imidazole (A1)) and a heat-resistant metal catalyst (hereinafter also referred to as specific metal catalyst (A2)) having a specific structure represented by the following formula (1) in its molecule, a liquid epoxy resin (hereinafter also referred to as liquid epoxy resin (B)), a liquid cyanate ester resin (hereinafter also referred to as liquid cyanate ester 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 proportion of the heat-resistant compound (A) to the total composition (X) is 0.01% to 3% by mass, the inorganic filler (D) is 40% to 65% by mass, and the reducing component (E) is 0.5% to 4% by mass.

[0015] Composition (X) exhibits excellent void suppression, meaning it is less likely to form voids, and can raise the glass transition temperature of the cured product to 85°C or higher. This improves the reliability of encapsulated semiconductor devices and other products obtained by encapsulating with composition (X), thus demonstrating excellent encapsulation reliability. In addition to its effects on void suppression and encapsulation reliability, composition (X) also exhibits excellent properties required for encapsulating resin compositions, including "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 connectivity in the formed mounting; and "pot life," which indicates storage stability.

[0016] 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. In composition (X), the heat-resistant compound (A) is at least one of a specific imidazole (A1) and a specific metal catalyst (A2) having a specific structure represented by formula (1), and is a compound that is poorly compatible with liquid epoxy resin (B) and liquid cyanate ester resin (C), has a small thermal weight loss rate at 250°C, and is not easily volatilized or thermally decomposed. By setting the proportion of this heat-resistant compound (A) within a specific range, the curing timing can be made appropriate and the chip connectability can be improved. Furthermore, by using the heat-resistant compound (A), liquid epoxy resin (B), and liquid cyanate ester 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 heat-resistant compound (A), a liquid epoxy resin (B), and a liquid cyanate ester resin (C), and by keeping the proportions of the inorganic filler (D) and reducing component (E) below a specific value, it is possible to reduce the gas generated from the heat-resistant compound (A), thereby improving void suppression. Furthermore, by using the heat-resistant compound (A) and keeping the proportion of the reducing component (E) below a specific value, it is thought that the pot life will be improved. In addition, composition (X) uses a liquid epoxy resin (B) and a liquid cyanate ester resin (C) as the curing resin components. Since the liquid epoxy resin (B) and the liquid cyanate ester resin (C) form a cross-linked structure, the glass transition temperature of the cured product can be made higher, reaching 85°C or higher, thereby improving the reliability of the sealant. As described above, composition (X) is considered to have excellent void suppression and sealant reliability, and in addition, excellent dispensability, shape retention, curing timing, tip connectability, and pot life.

[0017] Thus, according to this disclosure, it is possible to provide a sealing resin composition that is less prone to void formation and can improve the reliability of the sealant, as well as a semiconductor device.

[0018] 2. Details <Sealing Resin Composition> Composition (X) contains a heat-resistant compound (A), a liquid epoxy resin (B), a liquid cyanate ester 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.

[0019] Composition (X) exhibits excellent properties in terms of void suppression and sealant reliability, as well as dispensability, shape retention, curing timing, tip connectivity, and pot life (hereinafter also referred to as the properties of composition (X)). The individual components are described below.

[0020] [Heat-resistant compound] The heat-resistant compound (A) is a compound of at least one of the specified imidazole (A1) and the specified metal catalyst (A2). The specified imidazole (A1) is a heat-resistant imidazole, and the specified metal catalyst (A2) is a heat-resistant metal catalyst.

[0021] In the context of heat-resistant imidazoles and heat-resistant metal catalysts, "heat resistance" means that the thermogravimetric differential thermal analysis (e.g., Hitachi High-Tech Science's "TG / DTA7300") is used to measure the thermogravimetric analysis under conditions of a nitrogen stream of 200 mL / min, a temperature range from 30°C to 350°C, and a heating rate of 10°C / min, and that the thermogravimetric loss rate at 250°C is 10% or less.

[0022] The thermal weight loss rate of the specific imidazole (A1) and the specific metal catalyst (A2) at 250°C is preferably 9% or less, more preferably 5% or less, and even more preferably 2% or less.

[0023] (Specific Imidazoles) Imidazoles are compounds having an imidazole ring that can promote crosslinking reactions between liquid cyanate ester resins (C), between liquid epoxy resins (B) and liquid cyanate ester resins (C), and between liquid epoxy resins (B).

[0024] Specified imidazole (A1) is a heat-resistant imidazole having a specific structure represented by the following formula (1) within its molecule.

[0025]

[0026] In the above formula (1), * indicates a site that bonds to a moiety other than the specific structure represented by formula (1) in the specific imidazole (A1).

[0027] The specific structure in the specific imidazole (A1) is the structure of 2,4-diamino-1,3,5-triazine as represented by the above formula (1). It is considered that since the specific imidazole (A1) has this specific structure, it becomes difficult to dissolve in organic resins such as a liquid epoxy resin (B) and a liquid cyanate ester resin (C).

[0028] Examples of the moiety other than the specific structure in the specific imidazole (A1) include a substituted or unsubstituted imidazolyl group, and an alkanediyl group to which a substituted or unsubstituted imidazolyl group is bonded.

[0029] Examples of the substituent of the imidazolyl group include an alkyl group having 1 to 20 carbon atoms, and an alkyl group having 1 to 13 carbon atoms is preferable. The number of carbon atoms in 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.

[0030] It is preferable that the specific imidazole (A1) comprises a molecular structure represented by the following formula (2). That is, the specific imidazole (A1) 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.

[0031]

[0032] 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.

[0033] R １ and R ２ are preferably a hydrogen atom, a methyl group, an ethyl group, or an undecyl group.

[0034] Examples of the specific imidazole (A1) 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.

[0035] Examples of commercially available products of the specific imidazole (A1) include 2MZA, C11Z-A, and 2E4MZ-A (all manufactured by Shikoku Chemicals Corporation), and the like.

[0036] (Specific Metal Catalyst) The specific metal catalyst (A2) is a compound that can promote crosslinking reactions between liquid cyanate ester resins (C), between liquid epoxy resin (B) and liquid cyanate ester resin (C), or between liquid epoxy resins (B), and has heat resistance, that is, a thermogravimetric weight loss rate of 10% at 250°C.

[0037] It is preferable that the metal species in the specific metal catalyst (A2) include manganese, iron, cobalt, nickel, copper, and zinc.

[0038] As the specific metal catalyst (A2), an organometallic complex in which an organic compound is bonded to a metal atom as a ligand is preferable. As the organometallic complex, metal carboxylates and chelate complexes are preferable.

[0039] Examples of the specific metal catalyst (A2) include zinc octylate, cobalt(II) acetylacetonate, and the like, and examples of commercially available products include "Nikka Octic Zinc" manufactured by Nippon Chemical Industrial Co., Ltd., and the like.

[0040] It is important that the proportion of the heat-resistant compound (A) is 0.01% by mass or more and 3% by mass or less relative to the entire composition (X). When this proportion is outside the above range, the curing timing of the composition (X) becomes inappropriate, and characteristics such as chip connectivity deteriorate.

[0041] When the heat-resistant compound (A) is a specific imidazole (A1), the proportion of the specific imidazole (A1) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.4% by mass or more, relative to the total composition (X). The above proportion is preferably 2.8% by mass or less, and more preferably 2.6% by mass or less.

[0042] The amount of specific imidazole (A1) is preferably 0.2 parts by mass or more and 8 parts by mass or less, and more preferably 0.8 parts by mass or more and 6 parts by mass or less, based on 100 parts by mass of the total of liquid epoxy resin (B) and liquid cyanate ester resin (C).

[0043] When the heat-resistant compound (A) is a specific metal catalyst (A2), the proportion of the specific metal catalyst (A2) is preferably 0.02% by mass or more, and more preferably 0.03% by mass or more, relative to the entire composition (X). The above proportion is preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less.

[0044] The amount of the specific metal catalyst (A2) is preferably 0.01 parts by mass or more and 1 part by mass or less, and more preferably 0.03 parts by mass or more and 0.1 parts by mass or less, per 100 parts by mass of the total of the liquid epoxy resin (B) and the liquid cyanate ester resin (C).

[0045] [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.

[0046] "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.

[0047] The liquid epoxy resin (B) may be composed solely of components that are liquid at 25°C, or may be composed of a component that is liquid at 25°C and a component that is not liquid at 25°C.

[0048] 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 preferred.

[0049] Examples of the bisphenol-type epoxy resin include bisphenol A-type epoxy resins and bisphenol F-type epoxy resins.

[0050] As the liquid epoxy resin (B), it is preferable to include, for example, at least one of structures represented by the following formula (3) and the following formula (4). The following formula (3) represents a bisphenol-type epoxy resin, and the following formula (4) represents a glycidylamine-type epoxy resin. In these cases, various properties of the composition (X) can be further improved.

[0051]

[0052] 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.

[0053]

[0054] In the above formula (4), R ７ represents an alkyl group having 1 to 3 carbon atoms or a glycidyloxy group.

[0055] R in the above formula (3) ３ , R ４ , R ５ and R６ A hydrogen atom or a methyl group is preferred as the element. For n, for example, it is 10 or less, and 0 or 1 is preferred.

[0056] In the above formula (4), R ７ A methyl group or a glycidyloxy group is preferred.

[0057] 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) of the liquid epoxy resin (B) per 1 molL of epoxy group, and can be measured by a method in accordance with JIS-K-7236:2001.

[0058] 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).

[0059] The proportion of liquid epoxy resin (B) is preferably 20% by mass or more, and more preferably 24% 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.

[0060] The proportion of liquid epoxy resin (B) is preferably 50% by mass or more and 85% by mass or less, and more preferably 60% by mass or more and 75% by mass or less, relative to the total of liquid epoxy resin (B) and liquid cyanate ester resin (C).

[0061] [Liquid Cyanate Ester Resin] Cyanate ester resin is a compound having one or more cyanate ester groups (-O-CN) in one molecule, and is a component that can impart fluidity and curability to composition (X). As the cyanate ester resin, a compound having two or more cyanate ester groups in one molecule is preferred. In this case, the thermosetting properties of composition (X) can be further improved.

[0062] "Liquid cyanate ester resin" refers to a cyanate ester resin that is liquid at room temperature (25°C), and specifically a cyanate ester resin whose viscosity, measured at 25°C and atmospheric pressure, is 2000 Pa·s or less.

[0063] The liquid cyanate ester 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 cyanate ester resin that is solid at 25°C can be used by dissolving or dispersing it in a cyanate ester resin that is liquid at 25°C.

[0064] Composition (X) has improved dispensability because its viscosity can be reduced by containing liquid cyanate ester resin (C). In addition, the glass transition temperature of the cured product of composition (X) is increased because liquid cyanate ester resin (C) forms a crosslinked structure with other liquid cyanate ester resins (C) or with liquid epoxy resin (B).

[0065] The liquid cyanate ester resin (C) preferably contains one or more selected from the group consisting of bisphenol A type cyanate ester resin oligomer, bisphenol E type cyanate ester resin, dicyclopentadiene type cyanate ester resin, and phenol novolac type cyanate ester resin. In this case, the dispensability of composition (X) is further improved, and the glass transition temperature of the cured product can be further increased.

[0066] Examples of commercially available liquid cyanate ester resins (C) include "TA-100" manufactured by Mitsubishi Gas Chemical Company.

[0067] The cyanate ester group equivalent of the liquid cyanate ester resin (C) is preferably 50 g / mol or more and 1200 g / mol or less, more preferably 50 g / mol or more and 1000 g / mol or less, and even more preferably 50 g / mol or more and 500 g / mol or less. In this case, the dispensability of composition (X) is further improved, and the glass transition temperature of the cured product is further increased. "Cyanate ester group equivalent" means the molecular mass (g) of the cyanate ester resin (C) per 1 mol of cyanate ester groups.

[0068] The proportion of liquid cyanate ester resin (C) is preferably 5% by mass or more and 35% by mass or less, and more preferably 10% by mass or more and 30% by mass or less, relative to the total composition (X).

[0069] The amount of liquid cyanate ester resin (C) is preferably 30 parts by mass or more and 150 parts by mass or less, and more preferably 35 parts by mass or more and 130 parts by mass or less, per 100 parts by mass of liquid epoxy resin (B).

[0070] [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).

[0071] 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.

[0072] 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.

[0073] The shape of the inorganic filler (D) is not particularly limited and can be crushed, needle-shaped, flaky, spherical, etc. Among these, spherical fillers are preferred from the viewpoint of dispersibility and viscosity control in composition (X).

[0074] 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.

[0075] 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.

[0076] It is important that the proportion of inorganic filler (D) is 40% 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 42% by mass or more and 64% by mass or less, and more preferably 45% by mass or more and 60% by mass or less.

[0077] The amount of inorganic filler (D) is preferably 70 parts by mass or more and 150 parts by mass or less, and more preferably 90 parts by mass or more and 130 parts by mass or less, based on 100 parts by mass of the total of liquid epoxy resin (B) and liquid cyanate ester resin (C).

[0078] [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.

[0079] The reducing component (E) preferably contains at least one of the following: an organic acid (hereinafter also called organic acid (E1)) 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 (E2)) 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.

[0080] The reducing component (E) has a melting point of 220°C or lower, which allows it to remove the oxide film from the solder before melting, even when using solder with a melting point of around 200°C or above 200°C. Here, the "carboxyl group equivalent" of the organic acid (E1) means the molecular mass (g) of the organic acid (E1) per 1 molar of carboxyl groups. Also, the "nitrogen atom equivalent" of the amine (E2) means the molecular mass (g) of the amine (E2) per 1 molar of nitrogen atoms contained in the amine (E2).

[0081] Examples of organic acids (E1) include rosin component materials, adipic acid, glutaric acid, succinic acid, malonic acid, citric acid, corticic acid, sebacic acid, and pimelic acid. A commercially available example of organic acid (E1) is Tsunodaimu 395 (dimer acid: 94% by mass) manufactured by Tsukuno Foods Co., Ltd.

[0082] The organic acid (E1) 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).

[0083] The amine (E2) 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).

[0084] The reducing component (E) may include other components besides the organic acid (E1) and amine (E2), such as organic acids and amines with a melting point exceeding 220°C.

[0085] 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.

[0086] [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.

[0087] Composition (X) typically does not contain a solvent. Because composition (X) does not contain a solvent, a drying process after application becomes unnecessary.

[0088] 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).

[0089] Composition (X) can be prepared by blending and mixing, for example, a heat-resistant compound (A), a liquid epoxy resin (B), a liquid cyanate ester resin (C), an inorganic filler (D), a reducing component (E), and other components as needed.

[0090] Composition (X) is excellent in various properties such as void suppression and sealant reliability, and can therefore 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 various properties and reliability of the semiconductor device.

[0091] 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 and encapsulation reliability. Therefore, it can be suitably used as a pre-supplied encapsulation resin composition, that is, in a process in which the encapsulation resin composition is applied to a wiring board, interposer, etc., and then semiconductor elements are thermocompressed to perform encapsulation.

[0092] <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).

[0093] 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.

[0094] This semiconductor device (Y) is obtained by sealing any voids that may occur around a connection point with composition (X) during the manufacturing process of a semiconductor device in which a semiconductor element and a wiring substrate are electrically connected via a connection point.

[0095] The above-described composition (X) is excellent in various properties, including void suppression and sealant reliability, as well as dispensability, shape retention, curing timing, chip connectivity, and pot life. By using this to seal around the connection part, a semiconductor device (Y) with excellent properties and improved reliability can be obtained.

[0096] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0097] <Preparation of sealing resin composition> The sealing resin compositions of Examples 1 to 14 and Comparative Examples 1 to 9 were obtained by blending and mixing the types and parts by mass of each component shown in Tables 1 and 2 below. Details of each component are as follows.

[0098] (Heat-resistant compound (A)) (A1-1 to A1-3 and a1-1 to a1-3 are manufactured by Shikoku Chemicals Co., Ltd.) - A1-1: "2MZ-A" (2,4-diamino-6-[2'-(methylimidazolyl-1')ethyl]-s-triazine, thermal weight loss rate at 250°C: 1.5%) - A1-2: "C11Z-A" (2,4-diamino-6-[2'-(undecylimidazolyl-1')ethyl]-s-triazine, thermal weight loss rate at 250°C: 1.7%) - A1-3: "2E4MZ-A" (2,4-diamino-6-[2'-(ethylimidazolyl-1')ethyl]-s-triazine, thermal weight loss rate at 250°C: 8.1%) -a1-1: "2MA-OK" (2,4-diamino-6-[2'-(methylimidazolyl-1')ethyl]-s-triazine isocyanurate adduct, thermal weight loss rate at 250°C: 11.0%) -a1-2: "2P4MZ" (2-phenyl-4-methylimidazole, thermal weight loss rate at 250°C: 17.3%) -a1-3: "2PHZ" (2-phenyl-4,5-dihydroxymethylimidazole, thermal weight loss rate at 250°C: 13.2%) -A2-1: "Nikka Octix Zinc" manufactured by Nippon Chemical Industries, Ltd. (zinc octoate, thermal weight loss rate at 250°C: 3.2%) -A2-2: Cobalt(II) acetylacetonate manufactured by Tokyo Chemical Industries, Ltd. (thermal weight loss rate at 250°C: 5.0%)

[0099] (Liquid epoxy resin (B)) -B1-1: "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) -B1-2: "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) -B1-3: "EP-3950L" manufactured by ADEKA Corporation (liquid at 25°C, glycidylamine type epoxy resin, in formula (4) above, R ７ (Equivalent to glycidyloxy group and epoxy group: 95 g / mol)

[0100] (Liquid cyanate ester resin (C)) - C1: "TA-100" manufactured by Mitsubishi Gas Chemical Company (liquid at 25°C, cyanate ester group equivalent: 200 g / mol)

[0101] (Inorganic filler (D)) - D1: Spherical silica manufactured by Admatex (average particle size: 0.4 μm)

[0102] (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)

[0103] <Evaluation> The initial viscosity, dispensability, shape retention, curing timing, tip connectivity, void suppression, pot life, and sealant reliability of the prepared sealing resin composition were measured using the following methods.

[0104] (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.).

[0105] (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.

[0106] (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.

[0107] (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.

[0108] (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.

[0109] (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%.

[0110] (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 evaluated as A (Good) if the viscosity increase rate was 40% or less, and B (Poor) if the viscosity increase rate was more than 40%.

[0111] (Sealant Reliability) The sealing resin composition was poured into a cylindrical mold and heated at 150°C for 1 hour, then at 200°C for 3 hours to form a cured product. The demolded cured product was cut, and the cut surface was polished to obtain a cylindrical thermomechanical analysis sample with a diameter of 10 mm and a height of 20 mm. Using the obtained thermomechanical analysis sample, measurements were performed using a thermomechanical analyzer (TMA7100 manufactured by Hitachi High-Tech Science Corporation) under the conditions of a temperature range of 25°C to 250°C and a heating rate of 5°C / second. The temperature indicated by the intersection of the extensions of the straight lines on the low-temperature and high-temperature sides of the TMA curve obtained by the measurement was defined as the glass transition temperature. Sealing reliability was evaluated as A (good) if the glass transition temperature was "85°C or higher" and B (poor) if it was "less than 85°C".

[0112] 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 Example 6 indicates that the shape retention was not evaluated because the dispensability was poor.

[0113]

[0114]

[0115] As can be seen from the results in Tables 1 and 2, the encapsulating resin compositions of the examples exhibit excellent void suppression and encapsulant reliability, as well as excellent dispensability, shape retention, curing timing, tip connectivity, and pot life. The encapsulating resin compositions of the comparative examples are inferior in one or more of the following characteristics: void suppression and encapsulant reliability, as well as dispensability, shape retention, curing timing, tip connectivity, and pot life.

[0116] (Summary) As is clear from the above embodiments, the present disclosure includes the following embodiments. The sealing resin composition of the first embodiment contains a heat-resistant compound (A) selected from the group consisting of a heat-resistant imidazole (A1) and a heat-resistant metal catalyst (A2) having a specific structure represented by the above formula (1) in its molecule, a liquid epoxy resin (B), a liquid cyanate ester resin (C), an inorganic filler (D), and a reducing component (E). The proportion of the heat-resistant compound (A) to the whole sealing resin composition is 0.01% by mass or more and 3% by mass or less, the inorganic filler (D) is 40% 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.

[0117] According to the first embodiment, the sealing resin composition is excellent in void suppression and sealant reliability, as well as in dispensability, shape retention, curing timing, tip connectivity, and pot life.

[0118] In the second embodiment of the encapsulating resin composition, the heat-resistant imidazole (A1) comprises the molecular structure represented by the above formula (2), in the first embodiment.

[0119] According to the second embodiment, the encapsulating resin composition can further improve the above-mentioned properties.

[0120] 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).

[0121] According to the third aspect, the sealing resin composition can further improve the above-mentioned properties.

[0122] In the fourth embodiment of the sealing resin composition, in any one of the first to third embodiments, the liquid cyanate ester resin (C) comprises one or more selected from the group consisting of bisphenol A type cyanate ester resin oligomer, bisphenol E type cyanate ester resin, dicyclopentadiene type cyanate ester resin, and phenol novolac type cyanate ester resin.

[0123] According to the fourth embodiment, the sealing resin composition has improved dispensability and can raise the glass transition temperature of the cured product.

[0124] 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 20% by mass or more and 45% by mass or less of the total sealing resin composition.

[0125] According to the fifth aspect, the sealing resin composition can further improve the above-mentioned properties.

[0126] 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.

[0127] According to the sixth aspect, by using the sealing resin composition to seal voids in a semiconductor device, a semiconductor device with superior performance and improved reliability can be obtained.

[0128] 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.

[0129] According to the seventh aspect, the semiconductor device has excellent performance and improved reliability due to good sealing of the air gaps around the connection portion.

Claims

1. A sealing resin composition comprising: one or more heat-resistant compounds selected from the group consisting of heat-resistant imidazoles and heat-resistant metal catalysts having a specific structure represented by the following formula (1) in their molecule; a liquid epoxy resin; a liquid cyanate ester resin; an inorganic filler; and a reducing component, wherein the proportion of the heat-resistant compound to the entire sealing resin composition is 0.01% by mass or more and 3% by mass or less; the inorganic filler is 40% 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 sealing resin composition according to claim 1, wherein the liquid cyanate ester resin comprises one or more selected from the group consisting of bisphenol A type cyanate ester resin oligomer, bisphenol E type cyanate ester resin, dicyclopentadiene type cyanate ester resin, and phenol novolac type cyanate ester resin.

5. The sealing resin composition according to claim 1, wherein the proportion of the liquid epoxy resin is 20% 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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