Epoxy resin composition, electronic component, semiconductor device, and semiconductor device manufacturing method

Abstract

To provide: an epoxy resin composition capable of suppressing small pores generated when the surface of a cured product thereof is polished; an electronic component using the epoxy resin composition; a semiconductor device using the epoxy resin composition; and a method for manufacturing the semiconductor device.　The epoxy resin composition contains an epoxy resin, a curing accelerator, a filler, and an elastomer. The elastomer is at least one selected from a solid elastomer and a liquid elastomer. The solid elastomer has a structure in which a double bond is not included in the main chain.

Description

Epoxy resin composition, electronic component, semiconductor device, and method for manufacturing semiconductor device

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

[0002] Semiconductor devices, such as personal computers and smartphones, which incorporate semiconductor elements, are rapidly becoming smaller and more functional. Accordingly, improvements are being made to the methods of packaging semiconductor elements. One of these improvements is the improvement in package manufacturing methods. Traditionally, packages were manufactured after the semiconductor elements were separated into individual pieces, which meant that the package was always larger than the semiconductor element. As a result, packages manufactured using conventional packaging methods could not be mounted on small semiconductor devices. Therefore, a technology for manufacturing packages on wafers, before the semiconductor elements are separated into individual pieces (hereinafter referred to as wafer-level chip-size packaging technology), has come into use.

[0003] Wafer-level chip size packaging technology involves a process of encapsulating semiconductor elements with an encapsulant. One encapsulation method suitable for wafer-level chip size packaging technology is compression molding. Compression molding involves filling the cavity below the semiconductor element with a liquid encapsulant called liquid compression molding material and then allowing the encapsulant to harden.

[0004] As such a liquid sealing material, for example, Patent Documents 1 and 2 propose compositions containing an epoxy resin, a curing agent, and a filler.

[0005] International Publication No. 2018 / 221681 Pamphlet Japanese Patent Application Laid-Open No. 2015-105304

[0006] In wafer-level chip size packaging technology, after encapsulation with an encapsulant, a rewiring layer is formed on the portion of the cured encapsulant that corresponds to the circuit surface of the semiconductor element. Here, before forming the rewiring layer, the surface of the cured encapsulant is polished by a method such as chemical mechanical polishing (CMP) to flatten the surface of the cured encapsulant.

[0007] However, when the cured surface of the encapsulant is polished using the CMP method, small holes may occur on the cured surface. Such small holes may affect the uniformity of the thickness of the rewiring layer. If the thickness of the rewiring layer is not uniform, the contact between the rewiring layer and the circuit surface or solder balls of the semiconductor element may be poor. As a result, when the semiconductor element is mounted on a semiconductor device, the electrical connection between the semiconductor element and other semiconductor elements may not be uniform, which may cause defects in the semiconductor device.

[0008] The present invention aims to provide an epoxy resin composition that can suppress the formation of small holes when the surface of a cured product is polished, an electronic component using the epoxy resin composition, and a semiconductor device using the epoxy resin composition, as well as a method for producing the same.

[0009] To achieve the above object, one embodiment of the present invention is as follows. (1) An epoxy resin composition containing an epoxy resin, a curing accelerator, a filler, and an elastomer, wherein the elastomer is at least one selected from a solid elastomer and a liquid elastomer, and the solid elastomer has a structure having no double bonds in its main chain. (2) The epoxy resin composition according to (1), wherein the number of pores having a diameter of 0.05 μm to 0.5 μm present on the cured surface of the epoxy resin composition after polishing the surface by a first polishing step in which the cured surface is roughly polished and a second polishing step in which the cured surface is polished with a liquid containing an abrasive is 10 or less per predetermined area. (3) The epoxy resin composition according to (1) or (2), wherein the content of the elastomer is 5.0 mass% or more based on the components of the epoxy resin composition excluding the filler. (4) The epoxy resin composition according to any one of (1) to (3), wherein the solid elastomer is a core-shell type. (5) The epoxy resin composition according to any one of (1) to (4), wherein the content of the elastomer is 5.0% by mass to 20.0% by mass, based on the components of the epoxy resin composition excluding the filler. (6) The epoxy resin composition according to any one of (1) to (5), wherein the content of the filler is 73.0% by mass to 87.5% by mass. (7) The epoxy resin composition according to any one of (1) to (6), wherein the viscosity at 120°C is 0.5 Pa·s to 40.0 Pa·s. (8) The epoxy resin composition according to any one of (1) to (7), wherein the curing accelerator is a heterocyclic compound containing a nitrogen atom. (9) The epoxy resin composition according to any one of (1) to (8), wherein the curing accelerator is at least one curing agent selected from a phenol-based curing agent, an amine-based curing agent, and an acid anhydride-based curing agent. (10) The epoxy resin composition according to any one of (1) to (9), wherein the epoxy resin is at least one selected from the group consisting of an aliphatic epoxy resin and an aromatic epoxy resin.(11) The epoxy resin composition according to any one of (1) to (10) above, which is used as a liquid compression molding material. (12) An electronic component having a support and a cured product of the epoxy resin composition according to any one of (1) to (11) above. (13) A semiconductor device having the electronic component according to (12) above. (14) A method for manufacturing a semiconductor device, comprising the steps of filling a gap between a support and a semiconductor element disposed on the support with the epoxy resin composition according to any one of (1) to (11) above, curing the epoxy resin composition, and polishing the cured product of the epoxy resin composition.

[0010] According to the present invention, it is possible to provide an epoxy resin composition that can suppress the formation of small holes when the surface of a cured product is polished, an electronic component using the epoxy resin composition, and a semiconductor device using the epoxy resin composition and a method for producing the same.

[0011] Fig. 1 is an SEM image of the surface of the cured epoxy resin material after the second polishing of Example 1. Fig. 2 is an SEM image of the surface of the cured epoxy resin material after the second polishing of Comparative Example 1.

[0012] (Epoxy Resin Composition) The epoxy resin composition according to this embodiment contains an epoxy resin, a curing accelerator, a filler, and an elastomer, and preferably further contains a curing agent, and may further contain other components as necessary.

[0013] <Epoxy Resin> The epoxy resin is not particularly limited and can be selected appropriately depending on the purpose as long as it is any of various epoxy resins generally used for semiconductor encapsulation, and examples thereof include aliphatic epoxy resins, aromatic epoxy resins, etc. These may be used alone or in combination of two or more.

[0014] <<Aliphatic Epoxy Resin>> The aliphatic epoxy resin is contained in order to impart flexibility to a cured product of the epoxy resin composition (hereinafter also simply referred to as "cured product"), and examples thereof include monofunctional aliphatic epoxy resins, difunctional aliphatic epoxy resins, polyfunctional aliphatic epoxy resins, etc. These may be used alone or in combination of two or more.

[0015] Monofunctional aliphatic epoxy resins are compounds having one epoxy group in the molecule, and examples thereof include alkyl alcohol glycidyl ethers such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; and alkenyl alcohol glycidyl ethers such as vinyl glycidyl ether and allyl glycidyl ether.

[0016] The difunctional aliphatic epoxy resin is a compound having two epoxy groups in the molecule, and examples thereof include alkylene glycol diglycidyl ether, poly(alkylene glycol) diglycidyl ether, and alkenylene glycol diglycidyl ether.

[0017] Polyfunctional aliphatic epoxy resins are compounds having three or more epoxy groups in the molecule, and examples thereof include polyglycidyl ethers of trifunctional or higher alcohols such as trimethylolpropane triglycidyl ether, pentaerythritol (tri- or tetra-)glycidyl ether, and dipentaerythritol (tri-, tetra-, penta-, or hexa-)glycidyl ether. There is no particular upper limit to the number of epoxy groups, and this can be selected appropriately depending on the purpose, but 5 or less is preferred.

[0018] Among these, polyfunctional epoxy resins are preferred from the viewpoint of reliability (thermal cycle resistance) and the like.

[0019] The number average molecular weight of the aliphatic epoxy resin is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of imparting flexibility to the cured product of the epoxy resin composition, it is preferably 200 to 2,000. As a method for measuring the number average molecular weight of the aliphatic epoxy resin, a general method for measuring number average molecular weight can be used.

[0020] The aliphatic epoxy resin may be a synthesized product or a commercially available product, such as Epogosee PT (general grade) (manufactured by Yokkaichi Synthetic Co., Ltd.), YX7400 (manufactured by Mitsubishi Chemical Corporation), SR-8EGS (manufactured by Sakamoto Pharmaceutical Industry Co., Ltd.), or PG-207GS (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0021] <<Aromatic Epoxy Resin>> Examples of aromatic epoxy resins include glycidyl ethers of phenols, glycidyl ether esters of hydroxycarboxylic acids, monoglycidyl esters or polyglycidyl esters of carboxylic acids, glycidylamine-type epoxy resins, aminophenol-type epoxy resins, epoxy resins having a naphthalene skeleton, novolac resins, etc. These may be used alone or in combination of two or more.

[0022] Examples of glycidyl ethers of phenols include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, catechol, and resorcinol. Synthetic glycidyl ethers of phenols or commercially available products may be used. Examples of commercially available products include YDF8170 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), YDF870GS (manufactured by Nippon Steel Chemical & Material Co., Ltd.), EXA-850CRP (manufactured by DIC Corporation), EXA-835LV (manufactured by DIC Corporation), and EP4005 (manufactured by ADEKA Corporation).

[0023] Examples of the glycidyl ether ester of hydroxycarboxylic acid include p-hydroxybenzoic acid, etc. The glycidyl ether ester of hydroxycarboxylic acid may be a synthesized product or a commercially available product.

[0024] Examples of the monoglycidyl ester or polyglycidyl ester of carboxylic acid include benzoic acid, phthalic acid, terephthalic acid, etc. The monoglycidyl ester or polyglycidyl ester of carboxylic acid may be synthesized or may be a commercially available product.

[0025] Examples of glycidylamine-type epoxy resins include diglycidylaniline, diglycidyltoluidine, and tetraglycidyl-m-xylylenediamine. The glycidylamine-type epoxy resin may be a synthesized product or a commercially available product. Examples of commercially available products include EP3980S (manufactured by ADEKA Corporation) and ZX1059 (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0026] Examples of aminophenol-type epoxy resins include triglycidyl-p-aminophenol. The aminophenol-type epoxy resin may be a synthesized product or a commercially available product. Commercially available products include jER630 and jER630LSD (both manufactured by Mitsubishi Chemical Corporation) and EP3950L (manufactured by ADEKA Corporation).

[0027] Examples of epoxy resins having a naphthalene skeleton include glycidyl esters of naphthol and glycidyl ether esters of β-hydroxynaphthoic acid. The epoxy resins having a naphthalene skeleton may be synthesized or commercially available products. Examples of commercially available products include HP4032, HP4032D, and HP4032SS (all manufactured by DIC Corporation).

[0028] Examples of novolac resins include compounds obtained by converting phenols such as phenol, catechol, and resorcinol into novolacs. Synthesized novolac resins or commercially available products may be used. Examples of commercially available products include jER152 (manufactured by Mitsubishi Chemical Corporation).

[0029] Among these, the epoxy resin is preferably a mixture of an aliphatic epoxy resin and an aromatic epoxy resin, in order to improve the curing property while maintaining the hardness of the cured product of the epoxy resin.

[0030] The ratio (mass ratio) of the aliphatic epoxy resin to the aromatic epoxy resin is not particularly limited and can be appropriately selected depending on the purpose, but a ratio of aliphatic epoxy resin:aromatic epoxy resin=20% by mass to 40% by mass:60% by mass to 80% by mass is preferred.

[0031] <Curing Accelerator> The curing accelerator is contained to accelerate the crosslinking reaction between epoxy resins and increase the curing rate of the epoxy resin. When the epoxy resin composition is cured, the curing accelerator homopolymerizes with the epoxy resin. That is, the curing accelerator does not remain in the crosslinked structure formed by the epoxy resin. The curing accelerator is not particularly limited as long as it can cure the epoxy resin, and can be appropriately selected depending on the purpose. However, from the viewpoint of reliability (thermal cycle resistance), heterocyclic compounds containing a nitrogen atom are preferred.

[0032] <<Heterocyclic Compound Containing a Nitrogen Atom>> Examples of the heterocyclic compound containing a nitrogen atom include imidazole derivatives and microencapsulated heterocyclic compounds containing a nitrogen atom.

[0033] Examples of the imidazole derivative include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-imidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, benzimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, and 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole. These may be used alone or in combination of two or more. The imidazole derivative may be a commercially available product or an appropriately synthesized product. Examples of commercially available products include 2P4MZ (2-phenyl-4-methylimidazole) and 2MZA (2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 2-phenyl-4-methylimidazole) (both manufactured by Shikoku Chemicals Corporation).

[0034] The microencapsulated nitrogen-containing heterocyclic compound may be a commercially available product or may be appropriately synthesized. Commercially available products include, for example, Novacure HX3941HP, Novacure HXA3042HP, Novacure HXA3922HP, Novacure HXA3792, Novacure HX3748, Novacure HX3721, Novacure HX3722, Novacure HX3088, Novacure HX3741, Novacure HX3742, Novacure HX3613 (all manufactured by Asahi Kasei Corporation), Amicure PN-23J, Amicure PN-40J (all manufactured by Ajinomoto Fine-Techno Co., Ltd.), and Fujicure FXR-1121 (manufactured by Fuji Chemical Industry Co., Ltd.). These may be used alone or in combination of two or more types.

[0035] Of these, the nitrogen-containing heterocyclic compounds are preferably 2-phenyl-4-methylimidazole and 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine in terms of reactivity and storage stability.

[0036] The content of the nitrogen-containing heterocyclic compound is not particularly limited and can be appropriately selected depending on the purpose. However, it is preferably 2.0% by mass to 8.0% by mass, and more preferably 2.5% by mass to 6.0% by mass, based on the epoxy resin composition excluding the filler described below. When the content of the nitrogen-containing heterocyclic compound is 2.0% by mass or more, the curing time of the epoxy resin composition can be shortened, thereby improving the productivity of electronic component devices. When the content of the nitrogen-containing heterocyclic compound is 8.0% by mass or less, the storage stability of the epoxy resin composition can be improved. The content of the microencapsulated nitrogen-containing heterocyclic compound is preferably 3% by mass to 25% by mass, and more preferably 5% by mass to 20% by mass, of the active ingredient (nitrogen-containing heterocyclic compound) based on the epoxy resin composition excluding the filler. When the content of the microencapsulated nitrogen-containing heterocyclic compound is 3% by mass or more, the curing time of the epoxy resin composition can be shortened, thereby improving the productivity of electronic component devices. When the content of the microencapsulated nitrogen-containing heterocyclic compound is 25% by mass or less, the viscosity does not increase and deterioration of workability can be prevented.

[0037] <Filler> The filler is contained in the epoxy resin composition to adjust the properties of the cured product (mainly the linear expansion coefficient, elastic modulus, and water absorption).

[0038] The filler is not particularly limited and can be appropriately selected depending on the purpose. Examples include silica such as fused silica and crystalline silica; calcium carbonate, clay, alumina, silicon nitride, silicon carbide, boron nitride, calcium silicate, potassium titanate, aluminum nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, aluminum hydroxide, magnesium hydroxide, zinc borate, and zinc molybdate. These may be used alone or in combination of two or more. Among these, silica filler and alumina filler are preferred because they can increase the loading amount. The filler may be synthesized or commercially available. Examples of commercially available products include silica fillers such as SE101G-SMO (manufactured by Admatechs Co., Ltd.), SE605G-SMG (manufactured by Admatechs Co., Ltd.), and STW7010-20 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), and alumina fillers such as AG2051-SXM (manufactured by Admatechs Co., Ltd.).

[0039] The filler may be surface-treated. The surface treatment agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include silane coupling agents.

[0040] The silane coupling agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include epoxy-based, methacrylic-based, amino-based, vinyl-based, glycidoxy-based, mercapto-based, etc. Examples of commercially available products include KBM403, KBE403, KBM503, and KBM573 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0041] The volume average particle size of the filler is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 μm to 15.0 μm, more preferably 0.3 μm to 10.0 μm. In this embodiment, the volume average particle size refers to the particle size at which the cumulative volume particle size distribution measured by laser diffraction is 50%.

[0042] The shape of the filler is not particularly limited and can be appropriately selected depending on the purpose. Examples include spherical, irregular, and flaky shapes.

[0043] The filler content is preferably 73.0% by mass to 87.5% by mass, more preferably 75.0% by mass to 85.0% by mass, from the viewpoints of reducing the linear expansion coefficient of the cured product of the epoxy resin composition and workability. If the filler content is 73.0% by mass or less, the linear expansion coefficient of the cured product of the epoxy resin composition may increase, resulting in significant warpage. If the filler content is 87.5% by mass or more, the viscosity of the epoxy resin composition may increase, resulting in reduced workability.

[0044] <Elastomer> The elastomer is contained in order to impart injectability to the epoxy resin composition and to improve the adhesive strength of the cured product of the epoxy resin composition. The elastomer is at least one selected from a solid elastomer having a structure without double bonds in the main chain and a liquid elastomer, in order to suppress the formation of small holes when the surface of the cured product is polished. These elastomers may be used alone or in combination of two types.

[0045] When the surface of a cured product of a conventional epoxy resin composition containing an elastomer is polished, small holes may form. Three main reasons for this are believed to be responsible. The first is the shedding of elastomer moieties present in the cured product of the epoxy resin composition. Generally, cured products of elastomers have high abrasion resistance. Therefore, when a cured product of an epoxy resin composition is polished, the elastomer moieties in the cured product of the epoxy resin composition are polished along with the epoxy resin and filler moieties, and are removed from the surface of the cured product of the epoxy resin composition. These removed elastomer moieties become small holes. The second is the shedding of filler moieties present in the cured product of the epoxy resin composition. Depending on the polishing conditions, the filler may be removed without being polished, similar to the elastomer moieties described above. The third is damage to the polished surface of the cured product of the epoxy resin composition. Depending on the polishing conditions, the surface of the cured product of the epoxy resin composition may be subjected to physical impact rather than being polished, resulting in small holes. Therefore, in this embodiment, an elastomer with low abrasion resistance is used. It is believed that the use of such an elastomer can prevent small holes from forming when the surface of the cured product is polished.

[0046] <<Solid Elastomer>> A solid elastomer is an elastomer that is solid at room temperature (25°C) and has a structure that does not have a double bond in the main chain. An example of an elastomer that does not have a double bond in the main chain is silicone. Silicone has siloxane bonds, and has low surface abrasion resistance due to polishing, etc., which can prevent small holes from occurring when the surface of a cured product is polished and flattened.

[0047] The solid elastomer is preferably a core-shell type elastomer in terms of compatibility with epoxy resins. The core-shell type refers to a type in which the outside of a core (nucleus) is covered with a material different from the core. The core-shell type elastomer used in the embodiment is preferably an elastomer using a silicone resin for the core and an acrylic copolymer for the shell, because it exhibits a low elastic modulus within the temperature range in which the epoxy resin composition is used and can reduce the shrinkage stress of the epoxy resin composition.

[0048] When an epoxy resin composition is produced using a core-shell elastomer, the core-shell elastomer may be mixed at the same time when the other components of the epoxy resin composition are mixed. However, it is preferable to disperse the core-shell elastomer in the epoxy resin beforehand and then mix it, i.e., to carry out a masterbatch treatment and then mix it with other components of the epoxy resin composition to produce the epoxy resin composition.

[0049] <<Liquid Elastomer>> A liquid elastomer is also called a liquid elastomer, and is an elastomer that is liquid at room temperature (25° C.). There are no particular limitations on the liquid elastomer and it can be appropriately selected depending on the purpose. Examples of the liquid elastomer include a copolymer of butadiene and acrylonitrile (butadiene-acrylonitrile copolymer).

[0050] The content of the elastomer is preferably 5.0% by mass or more, more preferably 5.0% by mass to 20.0% by mass, and even more preferably 8.0% by mass to 17.0% by mass, based on the components excluding the filler from the epoxy resin composition. When the content of the elastomer is within this range, the adhesive strength can be improved and a decrease in workability due to high viscosity can be prevented.

[0051] <Curing Agent> The curing agent is contained to cure the epoxy resin. When the epoxy resin composition is cured, the curing agent undergoes addition polymerization with the epoxy resin. That is, the curing agent enters into the crosslinked structure formed by the epoxy resin. The curing agent is not particularly limited as long as it can cure the epoxy resin, and can be appropriately selected depending on the purpose. Examples of the curing agent include phenol-based curing agents, amine-based curing agents, and acid anhydride-based curing agents. These may be used alone or in combination of two or more.

[0052] The content of the curing agent is not particularly limited and can be selected appropriately depending on the purpose, but the stoichiometric equivalent ratio with the epoxy resin (curing agent equivalent / epoxy group equivalent) is preferably 0.01 to 1.00, more preferably 0.01 to 0.50, and even more preferably 0.08 to 0.30. The content of the curing agent is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 0.5 to 2.0 mass%, and more preferably 0.5 to 1.0 mass%.

[0053] <Other Components> The other components are not particularly limited as long as they are those typically used in epoxy resin compositions and can be appropriately selected depending on the purpose, and examples thereof include colorants such as coupling agents, dyes, pigments, and carbon black; silicone oils; surfactants; antioxidants; conventionally known flame retardants such as antimony oxides such as antimony trioxide, antimony tetraoxide, and antimony pentoxide, and brominated epoxy resins; ion trapping agents; leveling agents; antifoaming agents; reactive diluents, etc. These may be used alone or in combination of two or more.

[0054] The contents of other components are not particularly limited and can be appropriately selected depending on the purpose.

[0055] <Physical Properties of Epoxy Resin Composition> <<Viscosity>> The viscosity of the epoxy resin composition in this embodiment at 25°C is preferably 1,000 Pa·s or less, more preferably 700 Pa·s or less, and even more preferably 500 Pa·s or less. From the viewpoint of ease of handling, the viscosity of the epoxy resin composition at 25°C is preferably 150 Pa·s or more. In this specification, the viscosity is measured using an HB-DV viscometer at a rotation speed of 10 rpm.

[0056] <<Viscosity when hot (viscosity at 120° C.)>> In an embodiment, the viscosity of the epoxy resin composition at 120° C. is preferably 0.5 Pa·s to 40.0 Pa·s. The viscosity at 120° C. can be measured using a rheometer.

[0057] <Physical Properties of Cured Epoxy Resin Composition> The cured epoxy resin composition according to the embodiment has a surface with 10 or fewer small holes per predetermined area after the surface is polished by the first and second polishing steps. Here, small holes are those present on the polished surface of the cured product, each having a diameter of 0.05 μm to 0.5 μm. The diameter refers to the maximum length of a line connecting two points on the periphery of the small hole, and this also applies when the hole is elliptical rather than circular. The hole depth is 0.03 μm to 0.3 μm.

[0058] <<First Polishing>> The first polishing is performed by roughly polishing (grinding) the surface of the cured product. Specifically, it is performed using waterproof abrasive paper. Examples of the abrasive grain size of the abrasive paper include #600, #800, and #1200. Examples of polishing conditions when forming a polished surface by the first polishing include the following conditions. The surface of the cured product is polished using a Struers automatic polishing machine (Tegramin-20, manufactured by Struers) under the following conditions. Polishing member: Waterproof abrasive paper #600 Polishing time: 3 minutes The rotation speed and polishing load are as follows: Rotation speed: 150 rpm Polishing load: 10 N

[0059] <<Second Polishing>> The second polishing is performed after the first polishing using a liquid containing an abrasive. Examples of the liquid containing an abrasive include abrasive grains dispersed in water. The liquid containing an abrasive may also be an abrasive slurry. Specifically, the second polishing is chemical mechanical polishing (CMP), i.e., polishing using a polishing pad and a polishing slurry. Examples of polishing conditions for forming a polished surface by the second polishing include the following: The surface of the cured product is polished using a Struers automatic polishing machine (Tegramin-20, manufactured by Struers) under the following conditions in the order of Step 1 to Step 3. Step 1 Polishing member: Diamond slurry (6-PC, 6μ slurry (particle size range: 4μm to 8μm), manufactured by Engis Japan Co., Ltd.) Polishing time: 6 minutes Step 2 Polishing member: Diamond slurry (1-PC, 1μ slurry (particle size range: 0μm to 2μm), manufactured by Engis Japan Co., Ltd.) Polishing time: 3 minutes Step 3 Polishing member: Diamond slurry (Master prep, manufactured by BUEHLER, average particle size 0.05μm) Polishing time: 2 minutes The rotation speed and polishing load in steps 1 to 3 are as follows. Rotation speed: 150 rpm Polishing load: 10 N

[0060] The arithmetic mean roughness Ra of the polished surface of the cured product after the second polishing is preferably 500 nm or less, more preferably 300 nm or less, and even more preferably 100 nm or less. There is no particular lower limit to the arithmetic mean roughness Ra of the polished surface, and examples thereof include 10 nm or more and 20 nm or more.

[0061] The arithmetic surface roughness Ra of the polished surface can be calculated by, for example, measuring the surface of the cured epoxy resin composition after the second polishing using a confocal scanning electron microscope (OPTELICS H1200, manufactured by Lasertec Corporation) and using the method specified in JIS B 0601:2001.

[0062] The number of small pores on the surface of the cured epoxy resin composition polished by the first polishing and the second polishing can be measured by observing the surface with a scanning electron microscope (SEM) at a magnification of 5,000 times. The predetermined area referred to above refers to one field of view in SEM observation, and is approximately 3.9 μm ２ In SEM observation, the shading of the image obtained is determined according to the electron density. That is, the shading in the SEM image is determined by the type of compound.

[0063] <Method for producing epoxy resin composition> The method for producing the epoxy resin composition according to the embodiment is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a method of mixing and stirring the above-mentioned components. Note that, when the above-mentioned epoxy resin is solid, it is preferable to liquefy and fluidize it by heating or the like before mixing.

[0064] The components may be mixed simultaneously, or some of the components may be mixed first and the remaining components may be mixed later. If it is difficult to uniformly disperse the filler in the epoxy resin, the epoxy resin and the filler may be mixed first and the remaining components may be mixed later.

[0065] The device used for mixing and stirring is not particularly limited and can be appropriately selected depending on the purpose. Examples include a roll mill, a ball mill, a planetary mixer, a bead mill, a Henschel mixer, and a Raikai mixer equipped with a stirrer and a heating device.

[0066] <Uses of Epoxy Resin Composition> The epoxy resin composition according to the embodiment is an epoxy resin composition that can suppress the formation of small holes when the surface of a cured product is polished, and therefore can be suitably used as a liquid compression molding material.

[0067] (Electronic Component) The electronic component according to this embodiment includes a support and a cured product of the epoxy resin composition described above. Examples of the electronic component include a semiconductor element and a support encapsulated with the epoxy resin composition.

[0068] <Support> The support is not particularly limited as long as it can fix a semiconductor element, and can be appropriately selected depending on the purpose. For example, a substrate can be mentioned.

[0069] <<Substrate>> The substrate is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a lead frame, a pre-wired tape carrier, a wiring board, glass, a silicon wafer, etc. The size, shape, and material of the substrate are not particularly limited as long as they are used as ordinary substrates, and can be appropriately selected depending on the purpose.

[0070] <Semiconductor Element> The semiconductor element is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, resistor arrays, coils, and switches. The size, shape, and material of the semiconductor element are not particularly limited as long as they are used as ordinary semiconductor elements, and can be appropriately selected depending on the purpose.

[0071] The cured product of the epoxy resin composition is provided between the support and the semiconductor element. The thickness of the cured product of the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, 10 μm or more and 800 μm or less. The shape of the cured product of the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose.

[0072] (Semiconductor Device) The semiconductor device (semiconductor package) according to this embodiment includes the electronic components described above, and may further include other components as necessary. The other components are not particularly limited and can be selected appropriately depending on the purpose.

[0073] (Method for Manufacturing Semiconductor Device) The method for manufacturing a semiconductor device according to this embodiment includes a step of filling with an epoxy resin composition, a step of curing the epoxy resin composition, and a step of polishing the cured product of the epoxy resin composition, and may further include other steps as necessary.

[0074] <Step of Filling with Epoxy Resin Composition> The step of filling with the epoxy resin composition is a step of filling the gap between the support and the semiconductor element disposed on the support with the epoxy resin composition. The method of filling the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a dispensing method, a casting method, and a printing method. The amount of the epoxy resin composition to be filled is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include an amount such that the thickness of the cured product of the epoxy resin composition is 10 μm or more and 800 μm or less.

[0075] <Step of curing epoxy resin composition> The step of curing the epoxy resin composition is a step of curing the epoxy resin composition between the support and the semiconductor element. The method of curing the epoxy resin composition is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a method of heat-curing the support, the epoxy resin composition, and the semiconductor element while compressing them under reduced pressure (compression molding), a method of heat-curing a dispensed epoxy resin composition in a dryer, and a method of heat-curing a stencil-printed epoxy resin composition in a dryer.

[0076] <Step of polishing the cured product of the epoxy resin composition> The step of polishing the cured product of the epoxy resin composition is a step of polishing the surface of the obtained cured product of the epoxy resin composition to make the surface of the cured product flat. The polishing method is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include the first polishing method and the second polishing method described above.

[0077] <Other Steps> The other steps are not particularly limited and can be appropriately selected depending on the purpose. For example, a step of disposing a semiconductor element on a support, a step of forming a rewiring layer, and the like can be mentioned.

[0078] (Examples 1 to 13, Comparative Examples 1 to 4) Epoxy resin compositions were prepared according to the formulations shown in Tables 1 to 4. The epoxy resin, curing accelerator, filler, elastomer, curing agent, and coupling agent were weighed and dispersed in a ceramic three-roll mill (manufactured by Inoue Seisakusho Co., Ltd.) to form a paste, thereby preparing the epoxy resin compositions. Note that the numerical values ​​in the tables represent parts by mass unless otherwise specified.

[0079]

[0080]

[0081]

[0082]

[0083] The epoxy resins used in the examples and comparative examples are as follows: Bisphenol F type epoxy resin (YDF8170, epoxy equivalent 158 ​​g / eq., manufactured by Nippon Steel Chemical & Material Co., Ltd.) Aminophenol type epoxy resin (jER 630, epoxy equivalent 98 g / eq., manufactured by Mitsubishi Chemical Corporation) Aliphatic epoxy resin (Epogose PT (general grade), epoxy equivalent 435 g / eq., manufactured by Yokkaichi Synthetic Co., Ltd.)

[0084] The curing accelerators used in the examples and comparative examples are as follows: 2-phenyl-4-methylimidazole (2P4MZ, manufactured by Shikoku Chemical Industry Co., Ltd.) 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (2MZA, manufactured by Shikoku Chemical Industry Co., Ltd.) Imidazole compound (2P4MHZ, manufactured by Shikoku Chemical Industry Co., Ltd.)

[0085] The fillers used in the examples and comparative examples are as follows: Silica filler 1 (SE605G-SMG, surface treated with 3-methacryloxypropyltrimethoxysilane, average particle size 1.8 μm, top cut diameter 5 μm, manufactured by Admatechs Co., Ltd.) Silica filler 2 (SE101G-SMO, surface treated with 3-methacryloxypropyltrimethoxysilane, average particle size 0.3 μm, top cut diameter 1 μm, manufactured by Admatechs Co., Ltd.)

[0086] The elastomers used in the examples and comparative examples are as follows: Silicone rubber (core-shell type) (core-shell type silicone rubber particles, MX-965, manufactured by Kaneka Corporation, elastomer component 25%) Silicone composite powder (KMP605, manufactured by Shin-Etsu Chemical Co., Ltd., elastomer component 100%) Butadiene-acrylonitrile copolymer (carboxyl group-terminated butadiene-acrylonitrile copolymer, CTBN1008SP, manufactured by Chori GLEX Co., Ltd., elastomer component 100%) Butadiene rubber (core-shell type) (core-shell type butadiene rubber particles, MX-137, manufactured by Kaneka Corporation, elastomer component 33%) Polybutyl acrylate rubber (core-shell type) (core-shell type polybutyl acrylate rubber particles, ALBIDURE EP XP powder, manufactured by EVONIK Co., Ltd., elastomer component 100%) Silicone-acrylic composite rubber (Metablen S-2501, manufactured by Mitsubishi Chemical Corporation, elastomer component 100%) Acrylic rubber (core-shell type) (core-shell type acrylic rubber particles, Staphyloid AC3355, manufactured by Aica Kogyo Co., Ltd., elastomer component 100%)

[0087] The curing agents used in the examples and comparative examples are as follows: Phenol-based curing agent (MEH-8005, hydroxyl equivalent 139 g / eq. to 143 g / eq., manufactured by Meiwa Kasei Co., Ltd.) Amine-based curing agent (ETHACURE100PLUS, manufactured by Albemarle) Acid anhydride-based curing agent (HN-2200, manufactured by Showa Denko Materials K.K.)

[0088] Other components used in the examples and comparative examples are as follows: Coupling agent (3-isocyanatepropyltriethoxysilane, KBE-9007, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0089] The obtained epoxy resin compositions were measured and evaluated for viscosity, hot viscosity, adhesive strength, number of pores on the surface after polishing, and surface roughness. The measurement and evaluation results are shown in Tables 1 to 4.

[0090] <Viscosity, Hot Viscosity> Using an HB-DV viscometer (HB-DV1, manufactured by Brookfield) the viscosity of each epoxy resin composition immediately after preparation was measured at a liquid temperature of 25°C and 10 or 5 rpm, and evaluated based on the following evaluation criteria. -Evaluation Criteria- A: Viscosity of 1,000 Pa s or less B: Viscosity of more than 1,000 Pa s Furthermore, using a rheometer (MARSIII, manufactured by HAAKE), the hot viscosity at 120°C was measured. Each epoxy resin composition (0.3 mL±0.1 mL) was placed on a plate heated to 120°C, and measurement was started with a measurement frequency of 10 Hz, a strain amount of 0.5, a gap of 0.5 mm, and a measurement frequency of 1 second. The hot viscosity after 40 seconds was measured, and this was recorded as the measurement result of the hot viscosity at 120°C.

[0091] <Adhesive Strength> Each epoxy resin composition was adhered to a 10 mm square silicon chip using a mold so as to form a truncated cone shape with a bottom diameter of 5 mm, a top diameter of 3 mm, and a height of 6 mm, and then cured at 150°C for 2 hours to prepare a test specimen. The resin portion of this test specimen was peeled off using a bond tester (Dage 4000, manufactured by Nordson Advanced Technologies), and the shear adhesive strength was measured. The adhesive strength was evaluated based on the shear adhesive strength value and the following evaluation criteria. -Evaluation Criteria- A: Shear adhesive strength is 8 MPa or more B: Shear adhesive strength is 6 MPa or more but less than 8 MPa C: Shear adhesive strength is less than 6 MPa

[0092] <Number of holes on the surface after polishing> Each epoxy resin composition was compression molded onto a 12-inch silicon wafer to a thickness of 300 μm. The wafer was then cut into approximately 50 pieces, and the surface of the cured epoxy resin composition on each silicon wafer was polished by the first polishing method and then by the second polishing method.

[0093] The first polishing method was polishing with waterproof abrasive paper (#600) using a polishing machine (Tegramin-20, manufactured by Struers). The polishing time was 3 minutes, the rotation speed was 150 rpm, and the polishing load was 10 N. The second polishing method was polishing using a polishing machine (Tegramin-20, manufactured by Struers) in the order of steps 1 to 3 shown below. Step 1 Polishing member: Diamond slurry (6-PC, 6μ slurry (particle size range: 4μm to 8μm), manufactured by Engis Japan Co., Ltd.) Polishing time: 6 minutes Step 2 Polishing member: Diamond slurry (1-PC, 1μ slurry (particle size range: 0μm to 2μm), manufactured by Engis Japan Co., Ltd.) Polishing time: 3 minutes Step 3 Polishing member: Diamond slurry (Master prep, manufactured by BUEHLER, average particle size 0.05μm) Polishing time: 2 minutes The rotation speed and polishing load in steps 1 to 3 were as follows. Rotation speed: 150 rpm Polishing load: 10 N

[0094] The polished surface of the cured epoxy resin composition was observed under an SEM (MERLIN, manufactured by ZEISS) at a magnification of 50,000 times, and the number of holes with a diameter of 0.05 μm to 0.50 μm present in one field of view was counted, and the surface condition after polishing was evaluated based on the following evaluation criteria. The SEM image of Example 1 is shown in Figure 1, and the SEM image of Comparative Example 1 is shown in Figure 2. The area of ​​one field of view in the 50,000-magnification SEM observation was approximately 3.9 μm. ２ -Evaluation Criteria- A: The number of holes of 0.05 μm to 0.50 μm on the polished surface is 9 or less. B: The number of holes of 0.05 μm to 0.50 μm on the polished surface is 10 or more.

[0095] <Measurement of Surface Roughness (Ra)> The surface of the cured epoxy resin composition after the second polishing was measured using a confocal scanning electron microscope (OPTELICS H1200, manufactured by Lasertec Corporation), and Ra was calculated according to the method specified in JIS B 0601:2001. The measurement conditions were as follows: scan width: 100 μm, scan type: area, light source: Blue, cutoff value: 1 / 5, object lens: x100, contact lens: x14, digital zoom: x1, Z pitch: 10 nm. The Ra value was measured at three locations and the average value was calculated.

[0096] As shown in Tables 1 to 4, the epoxy resin compositions of the Examples were all rated "A" for the number of pores on the surface after polishing. These epoxy resin compositions were capable of suppressing the generation of small pores when the surface of a cured product is polished. On the other hand, the epoxy resin compositions of Comparative Examples 1 to 4, which used a solid elastomer having a double bond in the main chain as the elastomer, were all rated "B" for the number of pores on the surface after polishing. These results demonstrate that epoxy resin compositions containing a solid elastomer or liquid elastomer not having a double bond in the main chain as the elastomer can suppress the generation of small pores when the surface of a cured product is polished.

[0097] Although the embodiments and examples of the present invention have been described, they are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents.

Claims

1. An epoxy resin composition containing epoxy resin, a curing accelerator, a filler, and an elastomer, The elastomer is at least one selected from solid elastomers and liquid elastomers. An epoxy resin composition characterized in that the solid elastomer has a structure in which the main chain does not have double bonds.

2. The epoxy resin composition according to claim 1, wherein, after polishing the surface of the cured epoxy resin composition by a first polishing method that roughens the surface and a second polishing method that polishes the surface with a liquid containing an abrasive, the number of pores with a diameter of 0.05 μm to 0.5 μm present on the surface of the cured product is 10 or less per predetermined area.

3. The epoxy resin composition according to claim 1 or 2, wherein the content of the elastomer is 5.0% by mass or more relative to the components of the epoxy resin composition excluding the filler.

4. The epoxy resin composition according to claim 1 or 2, wherein the solid elastomer is of the core-shell type.

5. The epoxy resin composition according to claim 1 or 2, wherein the content of the elastomer is 5.0% by mass to 20.0% by mass relative to the components of the epoxy resin composition excluding the filler.

6. The epoxy resin composition according to claim 1 or 2, wherein the content of the filler is 73.0% by mass to 87.5% by mass.

7. The epoxy resin composition according to claim 1 or 2, wherein the viscosity at 120°C is 0.5 Pa·s to 40.0 Pa·s.

8. The epoxy resin composition according to claim 1 or 2, wherein the curing accelerator is a heterocyclic compound containing a nitrogen atom.

9. The epoxy resin composition according to claim 1 or 2, comprising at least one curing agent selected from phenolic curing agents, amine curing agents, and acid anhydride curing agents.

10. The epoxy resin composition according to claim 1 or 2, wherein the epoxy resin is at least one selected from aliphatic epoxy resins and aromatic epoxy resins.

11. The epoxy resin composition according to claim 1 or 2, used as a liquid compression molding material.

12. Support and An electronic component having a cured product of the epoxy resin composition according to claim 1 or 2.

13. A semiconductor device having the electronic component described in claim 12.

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