TW202426567A - Epoxy resin composition, cured product, and semiconductor device - Google Patents

Abstract

An epoxy resin composition for forming a cured product capable of preventing warping of a substrate and peeling from a chip, as well as a cured product and a semiconductor device using the same are provided. An epoxy resin composition comprises an epoxy resin, a filler, and at least one of a self-curing agent and a curing catalyst, wherein the epoxy resin comprises a flexible epoxy resin, and the content of the flexible epoxy resin is 8.0 mass % to 25.0 mass % relative to the epoxy resin.

Description

Epoxy resin composition, cured product and semiconductor device

The present invention relates to an epoxy resin composition, a cured product and a semiconductor device.

In recent years, semiconductor devices such as electronic equipment have become larger or thinner, and the importance of high-density mounting of semiconductor elements (also called chips) that constitute semiconductor devices has also increased. Therefore, the packaging method of semiconductor elements has gradually improved. In the past, semiconductor elements were packaged after being cut into individual pieces. This method is not suitable for large semiconductor devices because the package is larger than the chip. Therefore, it has gradually become a wafer-level packaging technology (wafer-level chip size packaging technology) that uses wafers without cutting them after the circuit is formed.

Wafer-level mounting is usually performed by filling a hardened resin composition called a sealant between the semiconductor element and the substrate to improve the semiconductor element's moisture resistance, heat resistance, and reliability against external stress. One of the sealing methods is a compression molding method in which the sealant is filled into the cavity below the semiconductor element and pressure is applied to harden the sealant (for example, see Patent Document 1). [Prior Technical Document] [Patent Document]

Patent document 1: Japanese Patent Application Publication No. 2021-161206

[Problems to be solved by the invention]

In wafer-level mounting, in addition to the steps of fixing the semiconductor element to the substrate and sealing the semiconductor element and the substrate with a resin composition, there is also a step of forming an electrical connection layer between the semiconductor element and the solder ball (the so-called redistribution layer formation step). Generally speaking, the order of the redistribution layer formation step and the resin composition sealing step is divided into the so-called chip first method (after mounting the semiconductor element on the substrate and sealing with the resin, the wiring layer is formed thereon) and the chip last method (after forming the redistribution layer on a wafer-shaped support made of Si or the like, mounting the semiconductor element for sealing, and finally removing the support). In particular, in the wafer-first method, since a redistribution layer is formed on a resin composition, it is required that the cured resin composition does not cause defects such as peeling off from a semiconductor element or the like during the redistribution layer formation step.

Furthermore, in wafer-level mounting, the mounted substrate is cut into individual pieces for IC chip packaging. Since the substrate warping is required to be small during the cutting step, a resin composition that can prevent the substrate warping is required.

The purpose is to provide an epoxy resin composition that can form a cured product that can prevent warping of a substrate and peeling from a chip, as well as a cured product and a semiconductor device using the same. [Means for solving the problem]

Conventional resin compositions can use epoxy resins and flexible epoxy resins together to prevent substrate warping. However, epoxy resin compositions containing a large amount of flexible epoxy resin may be immersed in the solvent of the developer used in the redistribution layer formation step, causing the semiconductor device to peel off.

As a result of studying this phenomenon, the inventors found that the cured product formed by the epoxy resin composition containing a large amount of flexible epoxy resin contains fine voids called microvoids in the cured product. It was also found that these microvoids easily absorb solvents into the cured product, deteriorating the tolerance of the cured product to solvents (solvent resistance), and that the deterioration of the solvent resistance of the cured product is the cause of the peeling of the semiconductor element. Therefore, the inventors repeatedly studied the ratio of the flexible epoxy resin and completed the present invention. In the present invention, microvoids refer to voids having a maximum width of 0.5 μm or less when a cross section is observed using a SEM image (accelerating voltage: 1 kV, magnification: 5000 times).

In order to achieve the above-mentioned purpose, one embodiment of the present invention is an epoxy resin composition, which contains epoxy resin, filler and at least one of a self-hardening agent and a hardening catalyst, wherein the epoxy resin contains a soft epoxy resin, and the content of the soft epoxy resin is 8.0 mass% to 25.0 mass% relative to the epoxy resin. [Effect of the invention]

According to the present invention, it is possible to provide an epoxy resin composition that forms a cured product capable of preventing warping of a substrate and separation from a chip, as well as a cured product and a semiconductor device using the same.

(Epoxy resin composition)

The epoxy resin composition according to the embodiment contains epoxy resin, filler, and at least one of a self-curing agent and a curing catalyst, and further contains other components as needed.

<Epoxy resin> Epoxy resin includes soft epoxy resin and other epoxy resins.

<<Flexible epoxy resin>> Flexible epoxy resin is contained in order to prevent the substrate on which the cured product of the epoxy resin composition is loaded from warping. In the embodiment, the flexible epoxy resin refers to an epoxy resin that meets the following three conditions. 1. The number average molecular weight is 800 to 2,500 2. The epoxy equivalent is 400 g/eq. to 1,200 g/eq. 3. The molecule does not contain condensed polycyclic hydrocarbons

The number average molecular weight of the flexible epoxy resin is 800 to 2,500, preferably 800 to 2,000. If the number average molecular weight is less than 800, the substrate may be warped, and if it exceeds 2,500, the ratio of microvoids may increase, the solvent resistance may deteriorate, and the substrate may be peeled off from the chip. The number average molecular weight can be determined by a general method. For example, it can be determined by gel permeation chromatography (GPC) using tetrahydrofuran as an elution solvent and converted to standard polystyrene.

The epoxy equivalent of the flexible epoxy resin is 400 g/eq. to 1,200 g/eq., preferably 400 g/eq. to 1,000 g/eq. If the epoxy equivalent is less than 400 g/eq., the substrate warping may increase, and if it exceeds 1,200 g/eq., the microvoid ratio in the cured product may increase, resulting in the problem of peeling off from the semiconductor element in the redistribution formation step. Here, the epoxy equivalent is the mass of the resin containing 1 equivalent of epoxy group as defined in JIS K7236: 2001. In addition, "eq." is an abbreviation of "equivalent".

Specific examples of the flexible epoxy resin include aliphatic epoxy resins. Aliphatic epoxy resins include polyalkylene glycol epoxy resins. Polyalkylene glycol epoxy resins include polytetramethylene glycol epoxy resins, polyethylene glycol epoxy resins, polypropylene glycol epoxy resins, and the like.

The flexible epoxy resin can be appropriately synthesized, and commercial products can also be used. Examples of commercial products include YX7400N (polytetramethylene glycol type epoxy resin, epoxy equivalent 440 g/eq., average molecular weight 880, manufactured by Mitsubishi Chemical Co., Ltd.), Epogosey-PT high molecular type (polytetramethylene glycol type epoxy resin, epoxy equivalent 1,072 g/eq., average molecular weight 2,140, manufactured by Yokkaichi Synthetic Co., Ltd.), Epogosey-PT general grade (polytetramethylene glycol type epoxy resin, epoxy equivalent 1,072 g/eq., average molecular weight 2,140, manufactured by Yokkaichi Synthetic Co., Ltd.), and Epogosey-PT standard grade (polytetramethylene glycol type epoxy resin). Resin, epoxy equivalent 435g/eq., average molecular weight 700~800, Yokkaichi Synthetic Co., Ltd.), SR-8EGS (polytetramethylene glycol type epoxy resin, epoxy equivalent 262g/eq., average molecular weight 510~550, Sakamoto Yakuin Kogyo Co., Ltd.), PG-207GS (polytetramethylene glycol type epoxy resin, epoxy equivalent 300~330g/eq., average molecular weight 600~660, NIPPON STEEL Chemical & Material Co., Ltd.), etc.

The content of the flexible epoxy resin is 8.0 mass% to 25.0 mass% relative to the entire epoxy resin, preferably 8.0 mass% to 16.5 mass%, and more preferably 9.0 mass% to 16.5 mass%. When the content of the flexible epoxy resin is within this range, it is possible to prevent wafer warping, inhibit the occurrence of micro voids, improve solvent resistance, and prevent peeling from the chip.

＜＜Other epoxy resins＞＞ Other epoxy resins are epoxy resins other than the aforementioned soft epoxy resins. Other epoxy resins are not particularly limited as long as they are various epoxy resins generally used for semiconductor sealing. They can be used appropriately according to the purpose. Preferably, they are liquid epoxy resins at room temperature (25°C). The epoxy equivalent of other epoxy resins can be 50g/eq.~10,000g/eq., preferably 50g/eq.~1,000g/eq., and more preferably 100g/eq.~500g/eq..

Other epoxy resins include, for example, epoxy propylamine type epoxy resins, alicyclic epoxy resins, bisphenol type epoxy resins, biphenyl type epoxy resins, aminophenol type epoxy resins, naphthalene type epoxy resins, etc. Examples of epoxy propylamine type epoxy resins include, for example, diglycidylaniline, diglycidyltoluidine, tetraglycidyl-m-xylenediamine tetraglycidylbis(aminomethyl)cyclohexane, etc. Examples of the alicyclic epoxy resin include ethylene dioxide (3,4-cyclohexene), 2-(3,4-epoxycyclohexyl)-5,1-spiro-(3,4-epoxycyclohexyl)-m-dioxane, etc. Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, etc. Examples of the bisphenol A type epoxy resin include p-glycidyloxyphenyl dimethyl tribisphenol A diglycidyl ether, etc. Examples of the biphenyl type epoxy resin include biphenyl aralkyl type epoxy resin and 3,3',5,5'-tetramethyl-4,4'-dihydroxipropyloxybiphenyl. Examples of the aminophenol type epoxy resin include trihydroxipropyl-p-aminophenol. Examples of the naphthalene type epoxy resin include 1,6-bis(2,3-epoxypropyloxy)naphthalene.

The number of epoxy groups contained in one molecule of other epoxy resins may be 1 (monofunctional epoxy resin) or 2 or more (polyfunctional epoxy resin). From the viewpoint of reliability (thermal cycling), 2 or more (polyfunctional epoxy resin) is preferred. The upper limit of the number of epoxy groups is not particularly limited and can be appropriately selected according to the purpose, but is preferably 5 or less. Examples of monofunctional epoxy resins include p-tert-butylphenyl glycidyl ether and the like. Examples of the polyfunctional epoxy resin include diepoxy resins such as 1,4-phenyl dimethanol diepoxypropyl ether, triepoxy resins such as trihydroxymethyl propane triepoxypropyl ether and glycerol triglyceride ether, etc. In addition to the above, hydantoin-type epoxy resins such as 1,3-diepoxypropyl-5-methyl-5-ethylhydantoin, epoxy resins having a silicon skeleton such as 1,3-bis(3-glycidoxypropyl)-1,1,3,3-tetramethyldisiloxane, and epoxy resins having a skeleton derived from plants are also possible.

Other epoxy resins may be used alone or in combination of two or more. Among these, aminophenol type epoxy resins, bisphenol type epoxy resins, and glycidylamine type epoxy resins are preferred from the viewpoint of reliability. Moreover, as other epoxy resins, it is preferred that aminophenol type epoxy resins are contained in a larger amount than other epoxy resins because the glass transition point of the epoxy resin composition increases.

Other epoxy resins may be appropriately synthesized or commercially available. Examples of commercially available epoxy resins include RE410S (bisphenol F type liquid epoxy resin, epoxy equivalent 178 g/eq, average molecular weight 360, manufactured by Nippon Kayaku Co., Ltd.), EP-3950L (glycidylamine type liquid epoxy resin, epoxy equivalent 95 g/eq, average molecular weight 270, manufactured by ADEKA Co., Ltd.), and the like.

The content of the epoxy resin (flexible epoxy resin and other epoxy resins) in the epoxy resin composition is preferably 10.0 mass% to 27.0 mass%, more preferably 15.0 mass% to 21.0 mass%, relative to the entire epoxy resin composition. When a bisphenol type epoxy resin is used as the other epoxy resin, the content of the bisphenol type epoxy resin is preferably 20 mass% to 30 mass% relative to the total amount of the epoxy resin. Furthermore, when a glycidylamine epoxy resin is used as the other epoxy resin, the content of the glycidylamine epoxy resin is preferably 50 mass % to 70 mass % relative to the total amount of the epoxy resin.

<Hardener, Curing Catalyst> The epoxy resin composition of the embodiment contains at least one of a hardener and a curing catalyst. The hardener is contained in order to harden the aforementioned epoxy resin, and the curing catalyst is contained in order to promote the curing of the aforementioned epoxy resin. The hardener and the curing catalyst may be used alone or in combination, and it is preferred to use them in combination from the viewpoint of accelerating the curing speed.

＜＜Hardener＞＞ The hardener is not particularly limited as long as it can cure the epoxy resin, and can be appropriately selected according to the purpose, and examples thereof include amine hardeners, phenol hardeners, and acid anhydride hardeners. Examples of amine hardeners include aromatic amines. Examples of aromatic amines include methylenedianiline, m-phenylenediamine, 4,4'-diaminodiphenylsulfone, and 3,3'-diaminodiphenylsulfone. Examples of phenol hardeners include phenol novolac resins, cresol novolac resins, naphthol-modified phenol resins, dicyclopentadiene-modified phenol resins, and p-xylene-modified phenol resins. Examples of anhydride curing agents include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, alkylated tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylnorbornenic anhydride, dodecenylsuccinic anhydride, and methylnadic anhydride. These can be used alone or in combination of two or more.

The hardener may be a properly synthesized one or a commercially available one. Examples of the commercially available hardener include MEH-8005 (phenol-based hardener, manufactured by Meiwa Chemicals Co., Ltd.) and HN-2200 (anhydride-based hardener, manufactured by Showa Denko Materials Co., Ltd.).

The content of the hardener is not particularly limited and can be appropriately selected according to the purpose. The stoichiometric equivalent ratio to the epoxy resin (hardener equivalent/epoxy equivalent) is preferably 0.01 to 0.50, more preferably 0.05 to 0.40, and more preferably 0.08 to 0.30. The content (ratio) of the hardener is preferably 1% to 30% by mass, more preferably 4% to 15% by mass, relative to the epoxy resin composition excluding the filler. If the content of the hardener is within this numerical range, it has the advantage of being able to prevent the substrate from warping and exhibiting sufficient bonding strength.

＜＜Curing Catalyst＞＞ The curing catalyst is not particularly limited as long as it is a curing catalyst used in general resin compositions, and can be appropriately selected according to the purpose, and can include tertiary amine compounds (excluding nitrogen atom-containing heterocyclic compounds), phosphorus-based curing accelerators, and nitrogen atom-containing heterocyclic compounds. These can be used alone or in combination of two or more. Among these, nitrogen atom-containing heterocyclic compounds are preferred from the perspective of reliability (thermal cycling). Nitrogen atom-containing heterocyclic compounds refer to compounds in which nitrogen atoms are constituent atoms of the heterocyclic ring.

Examples of the nitrogen atom-containing heterocyclic compound include imidazoles such as 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole; diazabicycloundecene (DBU), DBU-phenolate, DBU-octanoate, and DBU-p- Toluenesulfonate, DBU-formate, DBU-phthalate, DBU-phenol novolac resin, DBU-tetraphenylborate, diazonabiscyclononene (DBN), DBN-phenol novolac resin, diazonabiscyclooctane, pyrazole, oxazole, thiazole, imidazoline, pyrazine, morpholine, thiazine, indole, isoindole, benzimidazole, purine, quinoline, isoquinoline, quinoxaline, cinnoline, pteridine, etc. These may be used alone or in combination of two or more. Among these, preferred are (2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2-ethyl-4-methylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole from the viewpoint of reactivity.

The curing catalyst may be a synthetic one or a commercial one. Examples of commercially available products include 2MZA (2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, manufactured by Shikoku Chemicals Co., Ltd.), 2E4MZ (2-ethyl-4-methylimidazole, manufactured by Shikoku Chemicals Co., Ltd. 2-phenyl-4-methyl-5-hydroxymethylimidazole), and 2P4MHZ (2-phenyl-4-methyl-5-hydroxymethylimidazole, manufactured by Shikoku Chemicals Co., Ltd.).

The content of the curing catalyst is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of reactivity, it is preferably 0.1% by mass to 10% by mass, more preferably 0.5% by mass to 5% by mass, relative to the entire epoxy resin composition.

<Filler> Fillers are contained in order to adjust the cured properties of the epoxy resin composition (mainly linear expansion coefficient, elastic modulus, water absorption). The type of filler is not particularly limited and can be appropriately selected according to the purpose. For example, silica such as fused silica and crystalline silica; calcium carbonate, clay, aluminum, aluminum oxide, silicon nitride, silicon carbide, boron nitride, calcium silicate, potassium titanium oxide, aluminum nitride, curium oxide, zirconium oxide, zirconite, olivine, talc, spinel, mullite, titanium oxide, aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, etc. These can be used alone or in combination of two or more. Among these, silica filler is preferred from the perspective of being able to increase the filling amount.

The filler may be a surface treated filler. The surface treating agent is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include silane coupling agents and the like.

The silane coupling agent is not particularly limited and can be appropriately selected according to the purpose. For example, epoxy-based, methacryl-based, amino-based, vinyl-based, glycidoxy-based, butyl-based and the like can be cited.

The volume average particle size of the filler is not particularly limited and can be appropriately selected according to the purpose, for example, preferably 0.1 μm to 9.0 μm, more preferably 0.2 μm to 8.0 μm. In this embodiment, the volume average particle size refers to the volume average particle size D50 measured by laser diffraction (the particle size that accumulates to 50% from the small diameter side of the volume-based particle size distribution).

The shape of the filler is not particularly limited and can be appropriately selected according to the purpose. For example, spherical, amorphous, scaly, etc. can be mentioned.

The content of the filler can be 50% to 95% by mass, preferably 60% to 90% by mass, and more preferably 65% to 85% by mass, relative to the entire epoxy resin composition.

The content of filler contained in the epoxy resin composition can be measured according to the following method. First, the epoxy resin composition is measured in a crucible. The measured hardened material is heated to 850°C at a rate of 20°C/min and maintained at this temperature for 30 minutes. After cooling, the residue (burnt residue) remaining in the crucible is measured. The content of filler is calculated from the amount of filler obtained.

<Other components> As other components, there are no particular restrictions as long as they are used in conventional epoxy resin compositions, and they can be appropriately selected according to the purpose. Examples thereof include colorants such as dyes, pigments, and carbon black; silicone oils; surfactants; antioxidants; antimony oxides such as antimony trioxide, antimony tetroxide, and antimony pentoxide; conventionally known flame retardants such as brominated epoxy resins; ion scavengers; leveling agents; antioxidants; defoaming agents; reactive diluents; elastomers, etc. These may be used alone or in combination of two or more.

The content of other components is not particularly limited as long as it does not hinder the effects of the present invention, and can be appropriately selected according to the purpose.

<Physical properties of epoxy resin composition> <<Microvoids>> In this embodiment, microvoids refer to voids with a maximum width of 0.5 μm or less when observing the cross section of the cured product under the conditions of scanning electron microscope (SEM) (accelerating voltage: 1 kV, magnification: 5,000 times). Since microvoids have the property of absorbing solvents, a cured product with many microvoids absorbs a lot of solvents and has poor solvent resistance. Therefore, the degree of occurrence of microvoids is an indicator of solvent resistance. When an epoxy resin composition that forms a hardened material with many micro-voids is used as a sealant, the hardened material comes into contact with a solvent, and the solvent is absorbed into the hardened material, which reduces the adhesion between the semiconductor element (chip) sealed by the hardened material and the hardened material, causing peeling.

The ratio of microvoids (microvoid ratio) is measured as follows. The epoxy resin composition is heated at 150°C/1 hour to produce a cured product. The cured product is sliced with 50nm equal-spaced edges by a focused ion beam (FIB: COBRA (Orsay Physics)) and observed by SEM (AURIGA (Carl Zeiss), accelerating voltage: 1kV, magnification: 5,000 times) each time. In the SEM image, components with different electron densities appear as images with different densities. That is, fillers, resin components, and voids appear with different densities in the image. The continuous SEM images obtained are superimposed by 3D image processing software (Dragonfly (Ver.2022.1, manufactured by Object Research System)) to construct a 3D structure. After that, the filler, resin component, and void are set from the contrast difference of the obtained 3D structure, and the mechanical learning segmentation function that divides the image to identify the density of each area is used to identify and separate: filler, resin component, microvoid, and calculate the volume ratio of each component. The microvoid ratio is calculated using the following formula using the obtained volume ratio. The ratio of microvoids (microvoid ratio) is preferably less than 38%, and more preferably less than 30%.

[Number 1]

<<Solvent resistance>> A solvent is used in the redistribution layer formation step. Therefore, the possibility of the cured product being exposed to the solvent is high. Therefore, it is desired that the cured product has solvent resistance with the property of being insoluble in the solvent. In this embodiment, the evaluation of solvent resistance is performed based on the degree of mass change when the cured product is immersed in the solvent. Specifically, the cured product of the epoxy resin composition is immersed in the solvent for a predetermined time, and the mass change rate before and after the immersion in the solvent is calculated for evaluation. The mass change rate is preferably 0.50% or less, and more preferably 0.30% or less.

The solvents and immersion times used for evaluating solvent resistance include, for example, 30 minutes in propylene glycol monomethyl ether acetate heated to 60°C, 20 minutes in ethyl lactate at room temperature, 30 minutes in a 2.38% tetramethylammonium hydroxide solution at room temperature, and 30 minutes in a propylene glycol monomethyl ether acetate:propylene glycol monomethyl ether = 3:7 solution heated to 60°C.

＜＜Application＞＞ The epoxy resin composition according to the embodiment can be used as a liquid compression mold material because it becomes a hardened material capable of preventing warping of the substrate and peeling from the chip. In particular, since it contains a soft epoxy resin, it has good injectability that can be injected into fine grooves, and can be used for the installation of semiconductor devices that require installation of finer grooves (fine pitch). For example, even in a fine gap of 15μm or less between a substrate and a semiconductor element (chip), or a fine place of 150μm or less between bumps (the distance between bump centers), an epoxy resin composition can be injected to seal the semiconductor element. Furthermore, according to the epoxy resin composition of the embodiment, even when sealing such fine places, it is possible to prevent the substrate from warping and peeling off from the chip. As a result, cracks in the hardener that are the cause of peeling between the hardener and the chip can be prevented, and the occurrence of cracks between the hardener and the chip can be prevented.

<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 according to the purpose. For example, a method of mixing and stirring the above-mentioned components can be cited.

When the epoxy resin is solid, it is preferably mixed after being liquefied and fluidized by heating or the like.

In addition, the components may be mixed simultaneously, or a part of the components may be mixed first and the remaining components may be mixed later. For example, when 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.

The apparatus used for mixing and stirring is not particularly limited and can be appropriately selected according to the purpose. For example, a tumble mill, a ball mill, a bead mill, a pestle, a Henschel mixer, a planetary mixer and the like can be mentioned.

(Hardened product) The cured product according to the embodiment is obtained by curing the aforementioned epoxy resin composition. The size and shape of the cured product are not particularly limited and can be appropriately selected according to the purpose.

The method for producing the cured product is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include heating, transfer molding, compression molding, etc. The aforementioned epoxy resin composition is thermosetting and preferably cures in 0.1 to 3 hours, more preferably in 0.25 to 2 hours, at a temperature of 100°C to 200°C.

(Semiconductor device) According to the semiconductor device of this embodiment, there is a support, a semiconductor element, and a cured product of the above-mentioned epoxy resin composition. The cured product of the epoxy resin composition can be, for example, a device that fills and seals the gap between the semiconductor element and the support with the epoxy resin composition.

<Support> The support is not particularly limited as long as it can fix the semiconductor element, and can be appropriately selected according to the purpose, and examples thereof include a substrate, etc.

＜＜Substrate＞＞ The substrate is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include lead frames, tape carriers with completed wiring, wiring boards, glass, silicon wafers, etc. There are no particular restrictions on the size, shape, and material of the substrate as long as it is a substrate that is commonly used, and it can be appropriately selected according to the purpose.

<Semiconductor components> Semiconductor components are not particularly limited and can be appropriately selected according to the purpose. Examples include active components such as semiconductor chips, transistors, diodes, and gates; passive components such as capacitors, resistors, resistor arrays, coils, and switches. The size, shape, and material of semiconductor components are not particularly limited as long as they are commonly used as semiconductor components and can be appropriately selected according to the purpose.

The cured epoxy resin composition fills the gap between the support and the semiconductor element. The thickness of the cured epoxy resin composition is not particularly limited and can be appropriately selected according to the purpose, and can be, for example, 10 μm or more and 800 μm or less. The shape of the epoxy resin composition is not particularly limited and can be appropriately selected according to the purpose. The cured epoxy resin composition is arranged in the gap between the support and the semiconductor element to seal the semiconductor element.

The method for manufacturing the semiconductor device according to the present embodiment is not particularly limited and can be appropriately selected according to the purpose. For example, the semiconductor device can be manufactured through a step of filling an epoxy resin composition and a step of curing the epoxy resin composition.

The step of filling the epoxy resin composition is a step of filling the gap between the support and the semiconductor element with the epoxy resin composition. The method of filling the epoxy resin composition is not particularly limited and can be appropriately selected according to the purpose. For example, a dispensing method, a casting method, a printing method, etc. can be listed. The amount of the epoxy resin composition is not particularly limited and can be appropriately selected according to the purpose. For example, an amount that makes the thickness of the cured product 10 μm or more and 800 μm or less can be listed.

The step of hardening the epoxy resin composition is a step of hardening the epoxy resin composition between the support and the semiconductor element. The method of hardening the epoxy resin composition is not particularly limited and can be appropriately selected according to the purpose. For example, the support, epoxy resin composition, and semiconductor element can be transferred or compressed. [Example]

(Examples 1 to 14, Comparative Examples 1 to 3) The proportions listed in Tables 1 to 4 were mixed using a triple roll mill to uniformly disperse the components to obtain an epoxy resin composition.

The flexible epoxy resins used in the examples and comparative examples are as follows. • Flexible epoxy resin 1 (diglycidyl ether of polytetramethylene glycol, epoxy equivalent 440 g/eq., average molecular weight 880, trade name: YX7400N, manufactured by Mitsubishi Chemical Co., Ltd.) • Flexible epoxy resin 2 (diglycidyl ether of polytetramethylene glycol, epoxy equivalent 1,072 g/eq., average molecular weight 2,140, trade name: Epogosey-PT high molecular type, manufactured by Yokkaichi Synthetic Co., Ltd.)

The epoxy resins (epoxy resins other than flexible epoxy resins) used in the embodiments and comparative examples are as follows. • Epoxy resin 1 (Epoxypropylamine type liquid epoxy resin, epoxy equivalent 95 g/eq., average molecular weight 270, trade name: EP-3950L, manufactured by ADEKA Co., Ltd.) • Epoxy resin 2 (Bisphenol F type liquid epoxy resin, epoxy equivalent 178 g/eq., average molecular weight 360, trade name: RE410S, manufactured by Nippon Kayaku Co., Ltd.) • Epoxy resin 3 (Bisphenol F type liquid epoxy resin, epoxy equivalent 160 g/eq., average molecular weight 360, trade name: YDF870GS, manufactured by NIPPON STEEL Chemical & Material Co., Ltd.)

The hardeners used in the examples and comparative examples are as follows. • Hardener 1 (phenol-based hardener, hydroxyl equivalent 139~143g/eq., trade name: MEH-8005, manufactured by Meiwa Chemicals Co., Ltd.) • Hardener 2 (anhydride-based hardener, trade name: HN-2200, manufactured by Showa Denko Materials Co., Ltd.)

The hardening catalyst used in the examples and comparative examples is as follows. • Hardening catalyst (2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, trade name: 2MZA, manufactured by Shikoku Chemical Industries, Ltd.)

The fillers used in the embodiments and comparative examples are as follows. • Filler 1 (average particle size 0.3 μm, trade name: SE1050SMO, manufactured by Admatechs Co., Ltd.) • Filler 2 (average particle size 0.6 μm, trade name: SE2200SME, manufactured by Admatechs Co., Ltd.) • Filler 3 (average particle size 0.05 μm, trade name: YA050C-SM1, manufactured by Admatechs Co., Ltd.)

Other components used in the examples and comparative examples are as follows. • Black 4 (carbon black, manufactured by Orion Engineered Carbons Co., Ltd.) • KBM-403 (3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.)

The obtained epoxy resin composition was evaluated by measuring microvoids, solvent resistance, warping, and elastic modulus. The evaluation results are summarized in Tables 1 to 4.

＜Microvoids＞ The obtained epoxy resin compositions were heated at 150℃/1 hour to produce hardened products. The obtained hardened products were sliced at 50nm intervals by focused ion beam (FIB) and observed by SEM (accelerating voltage: 1kV, magnification: 5,000 times) each time. In SEM images, components with different electron densities appear as images with different densities. In other words, fillers, resin components and voids appear with different densities in the image. The obtained continuous SEM images were superimposed using 3D image processing software to construct a 3D structure. After that, fillers, resin components, and voids are set from the contrast difference of the obtained 3D structure, and the mechanical learning segmentation function that divides the image to identify the density of each area is used to identify and separate: fillers, resin components, microvoids, and calculate the volume ratio (%) of each component. The obtained volume ratio is used to calculate the microvoid ratio through the following formula, and the evaluation is based on the following evaluation criteria. In addition, the volume ratio of the filler does not participate in the calculation of the microvoid ratio. The device and 3D image processing software used in the measurement of microvoids are as follows. FIB: COBRA (Orsay Physics) SEM: AURIGA (Carl Zeiss) 3D image processing software: Dragonfly (Ver.2022.1, Object Research System)

[Number 2]

-Evaluation criteria- A: 0.0%~30.0% B: 30.1%~38.0% C: 38.1% or more

<Solvent resistance> For each epoxy resin composition, harden it at 150℃/1 hour to prepare a test piece with a size of 70mm wide, 150mm long, and 500μm thick. After measuring the initial mass of this test piece, immerse it in propylene glycol monomethyl ether acetate heated to 60℃ for 30 minutes. After removing the propylene glycol monomethyl ether acetate attached to the surface after immersion, measure the mass, calculate the mass increase (equivalent to the mass change rate) from the following formula, and evaluate based on the following evaluation criteria.

[Number 3]

-Evaluation criteria- A: 0.00%~0.30% B: 0.31%~0.50% C: 0.51% or more

<Warp> Using a molding machine (WCM-300, manufactured by APIC YAMADA Co., Ltd.), each epoxy resin composition was placed on a silicon wafer with a diameter of 300 mm and a thickness of 775 μm, and molded into a silicon wafer with a diameter of 292 mm and a thickness of 500 μm at 120°C/400 seconds, and then cured at 150°C/1 hour. The warp of the obtained silicon wafer molded product was measured using a shadow moire warp measuring device (TherMoiré AXP2.0 manufactured by Cerma Precison Co., Ltd.), and the warp was evaluated based on the following evaluation criteria.

-Evaluation criteria- A: Warp is less than 10,000μm B: Warp is more than 10,000μm or wafer cracks

<Elastic modulus> Each epoxy resin composition was cured at 150°C/1 hour to prepare a test piece with a width of 10.0 mm, a length of 50.0 mm, and a thickness of 2.0 mm. The obtained test piece was measured for storage elastic modulus at 30°C by the DCB method using a viscoelasticity analyzer (viscoelasticity measuring device DMA7100, manufactured by Hitachi High-Tech Science Co., Ltd.). The measurement conditions are as follows. Frequency: 1 Hz Strain amplitude: 10 μm Heating rate: 3°C/min

The determination results of microvoids in Examples 1 to 14 and Comparative Examples 1 to 3 are consistent with the determination results of solvent resistance. It can be seen that if the microvoid ratio is high, the solvent resistance deteriorates, and it is clear that one of the reasons for the deterioration of solvent resistance (peeling from the wafer) of the cured product of the epoxy resin composition is the occurrence of microvoids in the cured product.

The epoxy resin compositions of Examples 1 to 14 were all rated "B" or higher in terms of microvoids and solvent resistance, and all rated "A" in terms of warping. In contrast, Comparative Example 1, in which the ratio of the flexible epoxy resin was 26.4% by mass relative to the epoxy resin, was rated "C" in terms of microvoids and solvent resistance, and it is clear that when the ratio of the flexible epoxy resin exceeded 25% by mass relative to the epoxy resin, the solvent resistance deteriorated. Furthermore, in Comparative Example 2, in which the ratio of the flexible epoxy resin was 7.0 mass % relative to the epoxy resin, the warp evaluation result was "B", and it was clear that if the ratio of the flexible epoxy resin was less than 8.0 mass % relative to the epoxy resin, the warp deteriorated. Furthermore, in Comparative Example 3, which did not contain epoxy resin, wafer cracking occurred during the warp evaluation, and the warp of the substrate was worse than that of Comparative Example 2. From these results, it can be seen that the content of the flexible epoxy resin is 8.0 mass% to 25.0 mass% relative to the epoxy resin, which can suppress microvoids, has good solvent resistance, and can also prevent the warping of the substrate.

In Examples 1 to 7 and 10 to 11, where the content of the flexible epoxy resin was 8.0 mass% to 16.5 mass% relative to the epoxy resin, the microvoids and solvent resistance were judged as "A". In contrast, in Examples 8 to 9 and 12 to 13, where the content of the flexible epoxy resin was 16.5 mass% or more relative to the epoxy resin, the microvoids and solvent resistance were judged as "B". These results show that when the content of the flexible epoxy resin is set to 8.0 mass% to 16.5 mass% relative to the epoxy resin, the microvoid suppression and solvent resistance are better.

Although the embodiments and examples of the present invention have been described, they are disclosed only 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 changes can be made without departing from the scope of the invention. The embodiments and their modifications are included in the invention described in the patent application scope and its equivalent scope as well as those included in the scope and the gist of the invention.

Claims (10)

An epoxy resin composition, characterized in that it contains epoxy resin, filler, and at least one of a self-curing agent and a curing catalyst, The epoxy resin contains a flexible epoxy resin, The content of the flexible epoxy resin is 8.0 mass% to 25.0 mass% relative to the epoxy resin. The epoxy resin composition as claimed in claim 1, wherein the content of the flexible epoxy resin is 8.0 mass % to 16.5 mass % relative to the epoxy resin. The epoxy resin composition as described in claim 1 or 2, wherein the flexible epoxy resin is an aliphatic epoxy resin. The epoxy resin composition as described in claim 1 or 2, wherein the epoxy resin contains at least one selected from bisphenol type epoxy resin and glycidylamine type epoxy resin. The epoxy resin composition as described in claim 1 or 2, wherein the curing agent is selected from at least one of a phenolic curing agent, an amine curing agent and an anhydride curing agent. The epoxy resin composition as claimed in claim 1 or 2, wherein the content of the hardener is 4 mass % to 15 mass % relative to the epoxy resin composition before deducting the filler. The epoxy resin composition as described in claim 1 or 2 is used as a liquid compression mold material. The epoxy resin composition as described in claim 1 or 2 is used for sealing semiconductor chips with a bump pitch of less than 150μm. A hardened material obtained from the epoxy resin composition described in claim 1 or 2. A semiconductor device having a hardener as described in claim 9.