Epoxy resin composition, cured product, semiconductor device, and method for manufacturing semiconductor device

Abstract

To provide an epoxy resin composition having excellent injectability and giving a cured product having low warpage. The present invention also provides a cured product of the epoxy resin composition, a semiconductor device including the cured product, and a method for producing the semiconductor device.SOLUTION: An epoxy resin composition comprising an epoxy resin (A), a curing accelerator (B), and an inorganic filler (C), wherein the epoxy resin (A) comprises an aliphatic epoxy resin, and the curing accelerator (B) comprises an imidazole compound having a melting point of 170 °C or less and a molecular weight of 120 or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an epoxy resin composition, a cured product, a semiconductor device, and a method for producing a semiconductor device. [Background technology]

[0002] As electronic devices become smaller, lighter, and more powerful, the mounting method for semiconductors is changing from wire-bonding to flip-chip mounting. Flip-chip semiconductor devices have a structure in which electrodes on a substrate are connected to a semiconductor element via bump electrodes. When heat is applied to such semiconductor devices, stress is applied to the bump electrodes due to the difference in thermal expansion coefficients between the substrate and the semiconductor element, which causes problems such as cracks in the bump electrodes.

[0003] To prevent these defects, a semiconductor encapsulant called underfill is widely used. Underfill is a liquid encapsulant that is injected into the gap between the semiconductor element and the substrate and then thermally cured to fix the semiconductor element and the substrate together, thereby improving thermal cycle resistance. Another known method for further improving thermal cycle resistance is to incorporate an inorganic filler into the semiconductor encapsulant to reduce the thermal expansion coefficient of the cured product (encapsulant).

[0004] The injectability of a semiconductor encapsulant into gaps varies depending on the type and amount of resin and inorganic filler, etc. For example, Patent Document 1 discloses that a liquid epoxy resin composition containing a liquid epoxy resin and an inorganic filler, which uses an inorganic filler having a specific particle size and surface-treated with a specific compound, has excellent gap penetration ability (i.e., injectability). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-226673 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the liquid epoxy resin composition of Patent Document 1 has a problem in that warping occurs when the composition is cured after being applied to a substrate. One possible method for reducing warping during curing is to increase the amount of inorganic filler contained in the composition. However, increasing the amount of inorganic filler also causes a problem in that the injectability of the composition deteriorates. As such, there is a trade-off between injectability and warpage, and no epoxy resin composition that excels in both of these properties has been found to date.

[0007] Therefore, an object of the present invention is to provide an epoxy resin composition that has excellent injectability and a cured product thereof that exhibits low warpage, a cured product of the epoxy resin composition, a semiconductor device including the cured product, and a method for manufacturing the semiconductor device. [Means for solving the problem]

[0008] As a result of extensive research into achieving the above object, the present inventors have found that the above problems can be solved by using a composition having a specific structure. The present invention was completed based on these findings.

[0009] That is, in the present invention, Epoxy resin (A), a curing accelerator (B), and An epoxy resin composition containing an inorganic filler (C), The epoxy resin (A) contains an aliphatic epoxy resin, The epoxy resin composition contains, as the curing accelerator (B), an imidazole compound having a melting point of 170°C or lower and a molecular weight of 120 or higher.

[0010] The content of the aliphatic epoxy resin in the epoxy resin (A) is preferably 3 to 50 mass %.

[0011] The content of the inorganic filler (C) in the epoxy resin composition is preferably 90% by mass or less.

[0012] The reaction initiation temperature of the epoxy resin composition is preferably 130°C or higher.

[0013] The epoxy resin composition is preferably used for semiconductor encapsulation.

[0014] The present invention also provides a cured product of the above epoxy resin composition.

[0015] In the present invention, A substrate; a semiconductor element disposed on the substrate; the cured product that encapsulates the semiconductor element; and A semiconductor device comprising the same is also provided.

[0016] In the present invention, filling a gap between a substrate and a semiconductor element disposed on the substrate with the epoxy resin composition; curing the epoxy resin composition; A method for manufacturing a semiconductor device including the steps of: [Effects of the Invention]

[0017] The epoxy resin composition of the present invention has excellent injectability and a cured product thereof exhibits low warpage. Furthermore, a semiconductor device including a cured product of the epoxy resin composition exhibits high reliability because the semiconductor is encapsulated with high precision and the low warpage reduces stress on the bumps and encapsulant. [Brief explanation of the drawings]

[0018] [Figure 1] 10(a) to 10(c) are diagrams illustrating "Evaluation 3: Gap filling test" in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0019] (Epoxy resin composition) The epoxy resin composition includes an epoxy resin (A), a curing accelerator (B), and an inorganic filler (C), and includes an aliphatic epoxy resin as the epoxy resin (A), and an imidazole compound having a melting point of 170°C or lower and a molecular weight of 120 or higher as the curing accelerator (B).

[0020] Epoxy resin (A) The epoxy resin composition contains the epoxy resin (A), which allows it to form a cured product with high electrical insulation. The number of epoxy groups in the epoxy resin (A) is not particularly limited as long as it is one or more, but it is preferably two or more (i.e., a polyfunctional epoxy resin). The epoxy resin (A) can be used alone or in combination of two or more.

[0021] The epoxy resin (A) may be liquid or solid at room temperature (25°C), but is preferably liquid from the viewpoint of the viscosity of the epoxy resin composition. A solid epoxy resin can also be preferably used when it is used in combination with a liquid epoxy resin to form a liquid mixture.

[0022] The epoxy resin (A) is not particularly limited, and examples thereof include bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, and bisphenol AF type epoxy resins, bixylenol type epoxy resins, cyclohexane type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, and glycidylamine type epoxy resins. Examples of epoxy resins include epoxy resins (glycidyl amine type epoxy resins without an aromatic structure or glycidyl amine type epoxy resins with an aromatic structure), glycidyl ester type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins, aliphatic epoxy resins, epoxy resins with a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, tetraphenylmethane type epoxy resins, aminophenol type epoxy resins, and silicone-modified epoxy resins.

[0023] The epoxy resin composition of the present invention is characterized by containing an aliphatic epoxy resin as the epoxy resin (A). Aliphatic epoxy resins refer to epoxy resins whose intramolecular structure is primarily an aliphatic hydrocarbon group (e.g., a linear, branched, or alicyclic hydrocarbon group having two or more carbon atoms), and examples thereof include epoxy resins having a polyalkylene glycol chain. The polyalkylene glycol chain has repeating units of alkylene glycol having two or more carbon atoms (preferably 2 to 10, more preferably 3 to 6, and even more preferably 4 to 5 carbon atoms). The number of repeating units is not particularly limited, but is preferably, for example, three or more, more preferably five or more, and even more preferably ten or more. The number of repeating units is also not particularly limited, but is, for example, 200 or less, preferably 100 or less, and even more preferably 50 or less.

[0024] Examples of repeating units of alkylene glycol having two or more carbon atoms include ethylene glycol unit, propylene glycol unit, butylene glycol unit, tetramethylene glycol unit, hexamethylene glycol unit, octamethylene glycol unit, and decamethylene glycol unit. Aliphatic epoxy resins (particularly, epoxy resins having polyalkylene glycol chains) may contain one type of these repeating units alone or two or more types of units.

[0025] Examples of aliphatic epoxy resins include polyalkylene glycol diglycidyl ethers such as polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, and polyethylene glycol polypropylene glycol diglycidyl ether. Examples of other epoxy resins having a polyalkylene glycol chain include phenol-adduct epoxy resins such as diglycidyl ether of a propylene oxide adduct of bisphenol A, diglycidyl ether of a propylene oxide adduct of bisphenol F, and diglycidyl ether of a propylene oxide adduct of bisphenol S.

[0026] The epoxy resin composition exhibits low warpage due to the inclusion of an aliphatic epoxy resin. In other words, the cured product obtained by curing the epoxy resin composition tends to have reduced warpage. From the viewpoint of a balance between injectability and warpage, the epoxy resin composition preferably contains, as the epoxy resin (A) other than the aliphatic epoxy resin, at least one selected from the group consisting of bisphenol-type epoxy resins, naphthalene-type epoxy resins, aminophenol-type epoxy resins, cyclohexane-type epoxy resins, and glycidylamine-type epoxy resins, and more preferably at least one selected from the group consisting of bisphenol-type epoxy resins (particularly bisphenol A-type epoxy resins and bisphenol F-type epoxy resins) and glycidylamine-type epoxy resins.

[0027] Specific examples of liquid epoxy resins include "YDF-8170" and "YDF870GS" (both bisphenol F type epoxy resins), "YDF-8125" (bisphenol A type epoxy resin), "ZX-1658" and "ZX-1658GS" (all liquid 1,4-glycidylcyclohexane) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "HP-4032", "HP-4032D", and "HP-4032SS" (all naphthalene type epoxy resins) manufactured by DIC Corporation; and "jER828US" and "jER828E" manufactured by Mitsubishi Chemical Corporation. L (all bisphenol A type epoxy resins), "jER806", "jER807" (all bisphenol F type epoxy resins), "jER152" (phenol novolac type epoxy resin), "jER630", "jER630LSD" (all aminophenol type epoxy resins), "YX7400N" (aliphatic epoxy resin / polytetramethylene glycol diglycidyl ether); Epogosey PT (polytetramethylene glycol diglycidyl ether) from Yokkaichi Synthetic Co., Ltd.; and "ZX105" from Nippon Steel & Sumikin Chemical Co., Ltd. 9" (a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin); Nagase ChemteX Corporation's "EX-721" (glycidyl ester epoxy resin) and "EX171" (lauryl alcohol (EO) 15 glycidyl ether); ADEKA Corporation's "ADEKA Resin EP4005" (bisphenol A epoxy resin containing a polypropylene glycol structure), "EP-3950L", and "EP-3980S" (both glycidylamine epoxy resins); Asahi Kasei Corporation's AER9000 (PO-modified bisphenol A epoxy resin). These include "AER4001", "AER4004", and "AER4152" (all oxazolidone ring-containing epoxy resins) manufactured by The Dow Chemical Company, "DER852" and "DER858" (all oxazolidone ring-containing epoxy resins) manufactured by Nippon Kayaku Co., Ltd., "FAE-2500" and "EPPN-501HY" (all trisphenolmethane type epoxy resins) and "RE410S" (bisphenol A type epoxy resin); and "Celloxide 2021P" (alicyclic epoxy resin) manufactured by Daicel Corporation.

[0028] Specific examples of solid epoxy resins include "HP-4032H" (naphthalene-type epoxy resin), "HP-4700", and "HP-4710" (all naphthalene-type tetrafunctional epoxy resins), "N-690" (cresol novolac-type epoxy resin), "N-695" (cresol novolac-type epoxy resin), "HP-7200", "HP-7200L", "HP-7200HH", "HP-7200H", and "HP-7200HHH" (all dicyclopentadiene-type epoxy resins), all manufactured by DIC Corporation. ene-type epoxy resins), "EXA850CRP", "EXA7311", "EXA7311-G3", "EXA7311-G4", "EXA7311-G4S", and "HP6000" (all naphthylene ether-type epoxy resins); "EPPN-502H" (trisphenolmethane-type epoxy resin), "NC-7000-L" (naphthol novolac-type epoxy resin), "NC-3000-H", "NC-3000", "NC-3000-L", and "NC-310" manufactured by Nippon Kayaku Co., Ltd. 0" (all biphenyl-type epoxy resins); "ESN475V" (naphthol-type epoxy resin) and "ESN485" (naphthol novolac-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H" and "YL6121" (both biphenyl-type epoxy resins), "YX4000HK" (bixylenol-type epoxy resin), "YL7760" (bisphenol AF-type epoxy resin), and "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation. "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals Co., Ltd.; and "YL7800" (fluorene-type epoxy resin), "jER1010" (solid bisphenol A-type epoxy resin), "jER1031S" (tetraphenylethane-type epoxy resin), "jER157S70" (bisphenol novolac-type epoxy resin), "YX4000HK" (bixylenol-type epoxy resin), and "YX8800" (anthracene-type epoxy resin) manufactured by Mitsubishi Chemical Corporation.

[0029] The content of the epoxy resin (A) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 18% by mass or more, and particularly preferably 20% by mass or more. Also, for example, it is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 26% by mass or less. When the content of the epoxy resin (A) is within the above range, the epoxy resin composition has excellent injectability, and the cured product thereof tends to have reduced warpage.

[0030] The content of the aliphatic epoxy resin relative to the epoxy resin composition (100% by mass) is not particularly limited, but is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 2.5% by mass or more, and particularly preferably 3% by mass or more. It is also preferably 30% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 6% by mass or less, and particularly preferably 4% by mass or less. When the content of the aliphatic epoxy resin is within the above range, the epoxy resin composition has excellent injectability and the cured product thereof tends to have reduced warpage.

[0031] The content of the aliphatic epoxy resin relative to the epoxy resin (A) (100% by mass) is not particularly limited, but is, for example, preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 8% by mass or more, and particularly preferably 10% by mass or more. Also, for example, it is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, and particularly preferably 18% by mass or less. When the content of the aliphatic epoxy resin is within the above range, the epoxy resin composition has excellent injectability and the cured product thereof tends to have reduced warpage.

[0032] Curing accelerator (B) The curing accelerator (B) has the property of accelerating the curing of the epoxy resin. The curing accelerator is not particularly limited, but examples thereof include imidazole curing accelerators, tertiary amine curing accelerators, and phosphorus curing accelerators. The curing accelerator (B) can be used alone or in combination of two or more.

[0033] The epoxy resin composition of the present invention is characterized by containing, as a curing accelerator (B), an imidazole compound (hereinafter sometimes simply referred to as "imidazole compound") having a melting point of 170°C or less and a molecular weight of 120 or more. The imidazole compound is a curing accelerator equivalent to an imidazole-based curing accelerator. That is, the epoxy resin composition contains the imidazole compound as an imidazole-based curing accelerator. The epoxy resin composition may also contain an imidazole-based curing accelerator other than the imidazole compound. By containing the imidazole compound, the epoxy resin composition has excellent injectability, and the cured product thereof tends to have low warpage.

[0034] The imidazole compound used as the imidazole curing accelerator is not particularly limited as long as it is an imidazole having a melting point of 170°C or less and a molecular weight of 120 or more, and examples thereof include 1-benzyl-2-phenylimidazole (melting point 52 to 56°C, molecular weight 234), 1-(2-cyanoethyl)-2-undecylimidazole (melting point 50°C, molecular weight 275), 1-(2-cyanoethyl)-2-phenylimidazole (melting point 108°C, molecular weight 197), and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole (melting point 11°C, molecular weight 163), 2-undecylimidazole (melting point 71°C, molecular weight 222), 2-heptadecylimidazole (melting point 87°C, molecular weight 307), and 2-phenylimidazole (melting point 145°C, molecular weight 144). Examples of imidazole-based curing accelerators other than the above imidazole compounds include 2-phenyl-4-methylimidazole (melting point 179°C, molecular weight 158), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (melting point 253°C, molecular weight 219), 2-ethyl-4-methylimidazole (melting point 41°C, molecular weight 110), 2-methylimidazole (melting point 144°C, molecular weight 82), and 2-phenyl-4-methyl-5-hydroxymethylimidazole (melting point 193°C, molecular weight 188).

[0035] Commercially available imidazole curing accelerators include 2-ethyl-4-methylimidazole (product name "2E4MZ"), 2-phenyl-4-methylimidazole (product name "2P4MZ"), 2-phenyl-4-methyl-5-hydroxymethylimidazole (product name "2P4MHZ-PW"), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (product name "2MZA-PW"), "2MZ-OK", "2MA-OK", and "2PHZ", all manufactured by Shikoku Chemicals Corporation.

[0036] Examples of tertiary amine curing accelerators include benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine, triethanolamine, N,N'-dimethylpiperazine, triethylenediamine, 1,8-diazabicyclo[5.4.0]undecene, 1,5-diazabicyclo[4.3.0]nonene, and salts thereof. Examples of the salts include formate, octylate, p-toluenesulfonate, o-phthalate, phenol salt, or phenol novolac resin salt of 1,8-diazabicyclo[5.4.0]undecene, and formate, octylate, p-toluenesulfonate, o-phthalate, phenol salt, or phenol novolac resin salt of 1,5-diazabicyclo[4.3.0]nonene.

[0037] Examples of phosphorus-based curing accelerators include phosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, and 1,2-bis-(diphenylphosphino)ethane.

[0038] The content of the curing accelerator (B) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and most preferably 0.45% by mass or more. It is also, for example, preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less, even more preferably 4% by mass or less, and particularly preferably 2% by mass or less.

[0039] The content of the imidazole compound having a melting point of 170°C or less and a molecular weight of 120 or more relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, particularly preferably 0.2% by mass or more, and most preferably 0.45% by mass or more. Also, for example, it is preferably 8% by mass or less, more preferably 6% by mass or less, even more preferably 4% by mass or less, even more preferably 3% by mass or less, and particularly preferably 2% by mass or less. When the content of the imidazole compound is within the above range, the epoxy resin composition has excellent injectability, and the cured product thereof tends to have low warpage.

[0040] The content of the imidazole compound having a melting point of 170°C or less and a molecular weight of 120 or more relative to the epoxy resin (A) (100% by mass) is not particularly limited, but is, for example, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, even more preferably 1.5% by mass or more, even more preferably 1.8% by mass or more, and particularly preferably 2.0% by mass or more. Also, for example, it is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 9% by mass or less, and particularly preferably 8% by mass or less. When the content of the imidazole compound is within the above range, the epoxy resin composition tends to have excellent injectability, and the cured product thereof tends to have low warpage.

[0041] ·Inorganic filler (C) The inorganic filler (C) is not particularly limited, but is preferably (1) one having the property of suppressing volumetric shrinkage (cure shrinkage) caused by the curing reaction of the epoxy resin composition, (2) one having the property of suppressing volumetric change (thermal shrinkage) caused by heating of the cured product, i.e., one having the effect of lowering the linear expansion coefficient when added, or (3) one having both of these properties.

[0042] Examples of inorganic fillers (C) include silica (silicon dioxide), silicon carbide, silicon nitride, alumina (aluminum oxide), aluminum nitride, aluminum hydroxide, aluminum silicate, magnesium silicate, calcium silicate, calcium carbonate, barium sulfate, barium carbonate, titanium oxide, lime sulfate, potassium titanate, magnesium carbonate, zinc oxide, boron nitride, zirconia (zirconium oxide), and inorganic particles having their surfaces treated. Among these, silica is preferred from the viewpoint of increasing the loading amount. The inorganic filler (C) can be used alone or in combination of two or more.

[0043] In order to maintain the viscosity of the epoxy resin composition within an appropriate range, the inorganic filler (C) is preferably surface-treated with a coupling agent having a functional group such as an epoxy group, a (meth)acryloyl group, or an amino group (particularly a phenylamino group). Examples of the coupling agent include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. The surface treatment of the inorganic filler (C) can be carried out using one of the above coupling agents alone or in combination of two or more.

[0044] Commercially available inorganic fillers (C) include "YA050C-SM1" (silicon dioxide surface-treated with 3-methacryloxypropyltrimethoxysilane, average particle size 0.05 μm) and "SE1050-SMO" (silicon dioxide surface-treated with 3-glycidoxypropyltrimethoxysilane, average particle size 0.3 μm) manufactured by Admatechs Co., Ltd.

[0045] The shape of the inorganic filler (C) is not particularly limited, and examples thereof include spherical (e.g., spherical, nearly spherical), polyhedral, rod-like (e.g., cylindrical, prismatic), plate-like, flaky, and irregular shapes. Among these, spherical shapes are preferred from the viewpoint of achieving a high loading amount.

[0046] The average particle size of the inorganic filler (C) is not particularly limited, but is preferably 1 nm to 15 μm, more preferably 0.1 to 10 μm, and even more preferably 0.2 to 5 μm. When the average particle size of the inorganic filler (C) is within the above range, the particle size is not too large, and therefore the epoxy resin composition tends to have high filling properties even in narrow gaps. Two or more fillers with different average particle sizes may be used in combination to adjust the viscosity of the epoxy resin composition. In this specification, the method for measuring the average particle size of the inorganic filler (C) is not particularly limited, but can be measured, for example, using a laser diffraction / scattering particle size distribution analyzer (product name: LS 13 320, manufactured by Beckman Coulter, Inc.).

[0047] The content of the inorganic filler (C) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is preferably, for example, 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, particularly preferably 70% by mass or more, and most preferably 75% by mass or more. Furthermore, although not particularly limited, it is, for example, preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and particularly preferably 80% by mass or less. By having the content of the inorganic filler (C) within the above range, the epoxy resin composition has excellent injectability, and the cured product thereof tends to have low warpage.

[0048] The content of the inorganic filler (C) relative to the epoxy resin (A) (100% by mass) is not particularly limited, but is, for example, preferably 100% by mass or more, more preferably 200% by mass or more, even more preferably 250% by mass or more, and particularly preferably 280% by mass or more. Furthermore, although not particularly limited, it is, for example, preferably 600% by mass or less, more preferably 500% by mass or less, even more preferably 400% by mass or less, and particularly preferably 360% by mass or less. When the content of the inorganic filler (C) is within the above range, the epoxy resin composition has excellent injectability, and the cured product thereof tends to have low warpage.

[0049] Other ingredients (D) The epoxy resin composition may contain components other than the epoxy resin (A), the curing accelerator (B), and the inorganic filler (C) (hereinafter referred to as "other components (D)"). Examples of the other components (D) include curable compounds other than the epoxy resin (A), such as curing agents; thermoplastic resins such as polyethylene resins, polyester resins, polyurethane resins, and polyamide resins; coupling agents; core-shell rubber particles; ion trapping agents; leveling agents; antioxidants; antifoaming agents; flame retardants; colorants; reactive diluents; elastomers; and solvents. The other components (D) may be used singly or in combination of two or more.

[0050] The content of the other component (D) relative to the epoxy resin composition (100% by mass) is not particularly limited as long as it does not impair the effects of the present invention, but is, for example, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less. Furthermore, although not particularly limited, it is, for example, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 1% by mass or more.

[0051] The epoxy resin composition of the present invention may or may not contain a curable compound other than the epoxy resin (A), but from the viewpoints of injectability and low warpage, it is preferable that it does not contain any. The content of the curable compound other than the epoxy resin (A) relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 3% by mass or less, still more preferably 1% by mass or less, and particularly preferably 0.1% by mass or less.

[0052] Therefore, the epoxy resin composition may contain a curing agent, but preferably does not contain one. The curing agent is not particularly limited as long as it initiates, progresses, or accelerates the polymerization of the epoxy resin, and examples thereof include amine-based curing agents, acid anhydride-based curing agents, and phenol-based curing agents.

[0053] Examples of the amine-based curing agent include aromatic amines such as 4,4'-methylenebis(2-ethylaniline), 4,4'-diamino-3,3'-diethyldiphenylmethane, diethyltoluenediamine, dimethylthiotoluenediamine, methylenedianiline, m-phenylenediamine, 4,4'-diaminodiphenylsulfone, and 3,3'-diaminodiphenylsulfone. Examples of the acid anhydride-based curing agent include alkylated tetrahydrophthalic anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, phthalic anhydride, dodecenyl succinic anhydride, and methylnadic anhydride. Examples of the phenol-based curing agent include phenol novolac resin, cresol novolac resin, naphthol-modified phenolic resin, dicyclopentadiene-modified phenolic resin, and p-xylene-modified phenolic resin.

[0054] The content of the curing agent relative to the epoxy resin composition (100% by mass) is not particularly limited, but is, for example, preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, and still more preferably 0.01% by mass or less.

[0055] Coupling agents The coupling agent is not particularly limited, and examples thereof include silane coupling agents such as vinyl-based, glycidoxy-based, methacryl-based, amino-based, mercapto-based, and imidazole-based agents; titanium coupling agents such as alkoxide-based, chelate-based, and acylate-based agents; and long-chain spacer coupling agents such as glycidoxyoctyltrimethoxysilane and methacrylooctyltrimethoxysilane. Coupling agents can be used alone or in combination of two or more.

[0056] Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane.

[0057] The content of the coupling agent relative to the epoxy resin composition (100% by mass) is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and is preferably 5.0% by mass or less, more preferably 3.0% by mass or less.

[0058] The viscosity of the epoxy resin composition at 25°C is not particularly limited, but is preferably 1.0 Pa·s or more, more preferably 3.0 Pa·s or more, even more preferably 5.0 Pa·s or more, even more preferably 6.0 Pa·s or more, and particularly preferably 7.0 Pa·s or more. For example, the viscosity is preferably 40 Pa·s or less, more preferably 20 Pa·s or less, even more preferably 15 Pa·s or less, even more preferably 13 Pa·s or less, even more preferably 12 Pa·s or less, and particularly preferably 10 Pa·s or less. Having a viscosity within the above range tends to improve the injectability of the epoxy resin composition. The viscosity can be measured at a liquid temperature of 25°C by rotating at 50 rpm for 1 minute, as described in the Examples below, using an E-type viscometer (model number: TVE-25H, rotor name: 3°×R9.7, manufactured by Toki Sangyo Co., Ltd.).

[0059] As described above, the injectability of the epoxy resin composition tends to be good when the epoxy resin composition has a viscosity at 25°C within the above range, in other words, when the epoxy resin composition exhibits a relatively low viscosity. Here, the operation of injecting and filling the gap (gap) between a semiconductor element and a substrate with the epoxy resin composition involves a certain degree of heating (e.g., 80 to 110°C). In this operation, the low viscosity of the epoxy resin composition even under heated conditions is one factor that contributes to the good injectability. Therefore, when the viscosity of an epoxy resin composition at 25°C is low, the viscosity also tends to be low under heated conditions, which can be considered one factor contributing to the good injectability. However, the good injectability cannot be explained solely by the low viscosity of the epoxy resin composition at 25°C. This is because heating the epoxy resin composition may cause reactions between epoxy resins, which can increase the viscosity of the epoxy resin composition. In other words, the present invention has discovered an epoxy resin composition that exhibits good injectability by controlling the reactivity of the epoxy resin composition and maintaining the viscosity within an appropriate range under the heating conditions in the above operation.

[0060] The reaction initiation temperature of the epoxy resin composition is not particularly limited, but is preferably 120°C or higher, more preferably 125°C or higher, and even more preferably 130°C or higher. When the epoxy resin composition is injected into a gap, it is generally heated to reduce viscosity. However, if the reaction initiation temperature of the epoxy resin composition is set to a certain level as described above, thermal curing does not proceed during injection into the gap, and injectability does not decrease. The method for measuring the reaction initiation temperature is not particularly limited, but it can be measured, for example, by differential scanning calorimetry (DSC) using a differential scanning calorimeter, such as the method described in the Examples below.

[0061] (Method of producing epoxy resin composition) The epoxy resin composition can be prepared by a known, commonly used method. For example, the epoxy resin composition can be obtained by simultaneously or separately introducing at least one component selected from the group consisting of epoxy resin (A), curing accelerator (B), inorganic filler (C), and, if necessary, other components (D) such as a curing agent into an appropriate mixer and, if necessary, heating the components to melt them while stirring and mixing them. If the epoxy resin (A) is solid, it is preferable to heat it to liquefy or fluidize it before mixing. If it is difficult to uniformly disperse the inorganic filler (C) in the epoxy resin composition, the epoxy resin (A) and inorganic filler (C) can be heated and mixed to uniformly disperse the inorganic filler (C) in the epoxy resin (A), followed by cooling as necessary, and then mixing components such as the curing accelerator (B).

[0062] The mixer is not particularly limited, and examples thereof include a three-roll mill equipped with a stirrer and a heater, a roll mill, a Raikai mixer, a Henschel mixer, a tumbler, a planetary mixer, etc. The mixing ratio of each component is appropriately set depending on the content of each component in the epoxy resin composition.

[0063] The epoxy resin composition can be preferably used as a material for encapsulating semiconductor elements, wiring, solder (solder bumps), and other materials disposed on a substrate in a semiconductor device (an epoxy resin composition for semiconductor encapsulation). By using the epoxy resin composition as an epoxy resin composition for semiconductor encapsulation, a highly reliable encapsulated body can be produced. The epoxy resin composition can also be preferably used as a material for encapsulating semiconductor elements, etc., disposed on a substrate in a flip-chip semiconductor device (an epoxy resin composition for flip-chip semiconductor encapsulation). Specifically, by filling the gap between the semiconductor element, etc., and the substrate with the epoxy resin composition and subjecting it to thermal curing, the bump electrodes present in the gap can be encapsulated while the semiconductor element and the substrate are fixed together as an encapsulated body, thereby improving thermal cycle resistance.

[0064] The epoxy resin composition for semiconductor encapsulation is used, for example, as an underfill such as a capillary underfill, a liquid mold underfill, a secondary underfill, or a pre-applied underfill, a grab-top material, or a liquid compression molding material. The epoxy resin composition is not limited to the use as the epoxy resin composition for semiconductor encapsulation described above, and can also be used, for example, as an adhesive for fixing, joining, or protecting components that constitute electronic components.

[0065] (Cured product of epoxy resin composition) A cured product is formed by curing the epoxy resin composition. The curing method is not particularly limited, but for example, the curing can be carried out by subjecting the epoxy resin composition to a heat treatment. The heat treatment temperature is not particularly limited, but for example, 60 to 200°C is preferred, and 80 to 180°C is more preferred. The heat treatment time is not particularly limited, but for example, 0.1 to 5 hours is preferred, and 0.5 to 3 hours is more preferred.

[0066] (Semiconductor Devices) The semiconductor device of the present invention comprises a substrate, a semiconductor element disposed on the substrate, and a cured product of the epoxy resin composition that encapsulates the semiconductor element. The semiconductor device is preferably a flip-chip type semiconductor device. A flip-chip type semiconductor device has a structure in which electrodes on a substrate are connected to the semiconductor element via bump electrodes. In addition, in the semiconductor device, the gap between the semiconductor element and the substrate is encapsulated with a cured product (encapsulant) of the epoxy resin composition.

[0067] A semiconductor device can be manufactured by filling the gap between the substrate and a semiconductor element disposed on the substrate with the epoxy resin composition (filling step) and then heating and curing the epoxy resin composition (sealing step). The method for filling the gap with the epoxy resin composition is not particularly limited. For example, the epoxy resin composition can be applied to one end of the substrate or the semiconductor element while heating the substrate to 50 to 120°C, and the epoxy resin composition fills the gap between the substrate and the semiconductor element by capillary action. After filling the gap with the epoxy resin composition, the substrate is heated at a predetermined temperature for a predetermined time, specifically, at the temperature and for the time described above for the heat treatment in forming the cured product, thereby sealing the gap. [Example]

[0068] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0069] The epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were prepared by appropriately selecting and mixing the epoxy resin (A), curing accelerator (B), inorganic filler (C), and other components (D) in the proportions shown in Table 1. The numerical values ​​for each component in Table 1 indicate parts by mass.

[0070] Each component in Table 1 will be explained below. Epoxy resin (A) YX7400N (product name): Aliphatic epoxy resin (polytetramethylene glycol diglycidyl ether), liquid at 25°C, manufactured by Mitsubishi Chemical Corporation RE410S (product name): Bisphenol A epoxy resin, liquid at 25°C, manufactured by Nippon Kayaku Co., Ltd. jER630 (product name): Aminophenol-type epoxy resin (aromatic amine-type trifunctional epoxy resin), liquid at 25°C, manufactured by Mitsubishi Chemical Corporation EP-3980S (product name): Glycidylamine epoxy resin (aromatic amine-type bifunctional epoxy resin), liquid at 25°C, manufactured by ADEKA Corporation Curing accelerator (B) 1B2PZ (product name): 1-benzyl-2-phenylimidazole, melting point 52-56°C, molecular weight 234, manufactured by Shikoku Chemicals Corporation C11Z-CN (product name): 1-(2-cyanoethyl)-2-undecylimidazole, melting point 50°C, molecular weight 275, manufactured by Shikoku Chemicals Corporation 2PZ-CN (product name): 1-(2-cyanoethyl)-2-phenylimidazole, melting point 108°C, molecular weight 197, manufactured by Shikoku Chemicals Corporation 2E4MZ-CN (product name): 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole, melting point 11°C, molecular weight 163, manufactured by Shikoku Chemicals Corporation 2MZA (product name): 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, melting point 253°C, molecular weight 219, manufactured by Shikoku Chemicals Corporation 2E4MZ (product name): 2-ethyl-4-methylimidazole, melting point 41°C, molecular weight 110, manufactured by Shikoku Chemicals Corporation ·Inorganic filler (C) Silica filler: 3-methacryloxypropyltrimethoxysilane surface-treated silica, average particle size 1.5 μm, top cut diameter 3.0 μm, manufactured by Admatechs Co., Ltd. Other ingredients (D) YH307 (product name): Acid anhydride curing agent, manufactured by Mitsubishi Chemical Corporation Black 4: Product name "Special Black 4 powder", carbon black, manufactured by Orion Engineered Carbon Co. KBM-403 (product name): 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.

[0071] (Evaluation 1: Measurement of reaction initiation temperature of composition using DSC) Five mg of each of the epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 was weighed into an aluminum pan, sealed with an aluminum lid, and a hole was pierced in the center of the lid with a needle to prepare a measurement sample. Using a differential scanning calorimeter (DSC 204 F1 Phoenix, manufactured by NETZSCH Corporation), the measurement sample was heated in a nitrogen atmosphere over a range of 25 to 250°C at a rate of 5°C / min, while measuring the heat flow (mW / mg), and the exothermic heat initiation temperature was calculated using analysis software. This exothermic heat initiation temperature was used as the reaction initiation temperature for each epoxy resin composition. The results are shown in Table 1 under the heading "Reaction initiation temperature (°C)."

[0072] (Evaluation 2: Viscosity measurement at 25°C) The viscosity (Pa s) of the epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 at 25°C immediately after preparation was measured using an E-type viscometer (model number: TVE-25H, rotor name: 3° x R9.7, manufactured by Toki Sangyo Co., Ltd.) at a liquid temperature of 25°C, rotating at 50 rpm for 1 minute. The results are shown in Table 1 under "Viscosity (Pa s) at 25°C." The evaluation criteria were as follows: [Evaluation criteria] ○: Viscosity at 25℃ is less than 10 Pa·s △: Viscosity at 25℃ is 10 or more and less than 20 Pa.s ×: Viscosity at 25°C is 20 Pas or more

[0073] (Evaluation 3: Gap filling test) Preparation of test specimens A glass plate was attached to a resin substrate (FR4) with tape to obtain a test specimen with a gap between the FR4 and the glass plate, measuring 50 μm in height, 1 cm in width, and 2 cm in distance.

[0074] Testing and evaluation The test piece was placed on a hot plate set to 90°C, and approximately 0.2 g of each of the epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 was applied to the sample application area, and the time required for the filling distance to reach 2 cm was measured.

[0075] The gap filling test will be explained using Figure 1. In Figure 1, 1 represents a test specimen. 2 represents a glass plate, 2' a resin substrate (FR4), 3 a tape, 4 a gap, and 5 an evaluation sample. (a) is a plan view of the test specimen 1, with the longitudinal direction of the test specimen 1 being vertical and the lateral direction being horizontal. (b) is a side view of the test specimen 1 from the longitudinal direction. (c) is a side view of the test specimen 1 from the lateral direction. The glass plate 2 is laminated to the resin substrate 2' via the tape 3. As shown in (b), the edge of the glass plate 2 is the application area (sample application area) of the evaluation sample 5. The gap 4 is a space surrounded by the glass plate 2 on its upper surface, the resin substrate 2' on its lower surface, and two tapes 3 on its sides. In the gap 4, the distance between the glass plate 2 and the resin substrate 2' (gap height) is 50 μm, and the distance between the two tapes 3 (gap width) is 1 cm. The longitudinal distance of the gap 4 (gap distance) is 2 cm. The test piece 1 is placed on a hot plate (not shown), and the evaluation sample 5 is applied to the sample application area. The applied evaluation sample 5 moves downward through the gap 4 (a) due to capillary action. The time it takes for the evaluation sample 5 to reach the edge of the slide glass 2' is measured, and the result is recorded as "Injectability (sec)" in Table 1. If the evaluation sample 5 has not reached the edge after 1000 seconds or more have passed, the evaluation is stopped immediately, and the result is recorded as "Stop" in Table 1. The evaluation criteria are as follows: [Evaluation criteria] ○: Time to reach the end is less than 600 seconds ×: Time to reach the end is 600 seconds or more (including Stop)

[0076] (Evaluation 4: Warpage test) The epoxy resin compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were applied to a cover glass measuring 24 mm x 32 mm x 0.15 mm thick, so as to have a size of 24 mm x 24 mm x approximately 50 μm thick. After curing at 150°C for 1 hour, the unevenness of the cover glass surface was measured in two diagonal lines using a surface roughness and shape measuring device (Surfcom 1500SD2, manufactured by Tokyo Seimitsu Co., Ltd.). This procedure was repeated three times, and the average value of the sum of the maximum peak height and maximum valley depth was taken as the warpage. The results are shown in the "Warpage (μm)" column of the evaluation results in Table 1. The evaluation criteria were as follows: [Evaluation criteria] ○: Warpage is less than 200 μm ×: Warpage is 200 μm or more

[0077] [Table 1] [Explanation of symbols]

[0078] 1 test piece 2 glass plates 2' Resin substrate 3 Tape 4. Gap 5 Evaluation sample

Claims

1. Epoxy resin (A), a curing accelerator (B), and An epoxy resin composition containing an inorganic filler (C), The epoxy resin (A) contains an aliphatic epoxy resin, An epoxy resin composition comprising, as a curing accelerator (B), an imidazole compound having a melting point of 170°C or less and a molecular weight of 120 or more.

2. 2. The epoxy resin composition according to claim 1, wherein the content of the aliphatic epoxy resin relative to the epoxy resin (A) is 3 to 50 mass%.

3. 3. The epoxy resin composition according to claim 1, wherein the content of the inorganic filler (C) is 90 mass% or less.

4. 3. The epoxy resin composition according to claim 1, wherein the reaction initiation temperature is 130°C or higher.

5. 3. The epoxy resin composition according to claim 1, which is used for semiconductor encapsulation.

6. A cured product of the epoxy resin composition according to claim 1 or 2.

7. A substrate; a semiconductor element disposed on the substrate; The cured product according to claim 6 that encapsulates the semiconductor element; A semiconductor device comprising:

8. a step of filling a gap between a substrate and a semiconductor element disposed on the substrate with the epoxy resin composition according to claim 1 or 2; a step of heating and curing the epoxy resin composition; A method for manufacturing a semiconductor device comprising:

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