WO2023171028A1 - Resin composition, semiconductor device, and methods for producing same - Google Patents

Abstract

Provided is a resin composition that is used as a capillary underfill (CUF) capable of further reducing filament cracking.　Provided is a resin composition containing (A) an epoxy resin, (B) a curing agent, and (C) a filler. A cured product of this resin composition has a stress intensity factor range ΔKth for the fatigue crack propagation lower limit of 0.55 MPa∙m0.5 or greater.

Description

Resin composition, semiconductor device, and manufacturing method thereof

The present disclosure relates to a resin composition. More specifically, a resin composition used as a semiconductor encapsulant, especially an underfill material (CUF), a semiconductor device using the resin composition, a method for manufacturing the semiconductor device, and the resin composition. Relating to a manufacturing method.

When mounting flip-chip connections, BGA (Ball Grid Array), or CSP (Chip Size Package), there should be no underfill material protruding (fillet) or bump joints around semiconductor elements or other electronic components. , stress or strain may have accumulated due to hardening. In this case, peeling or cracking may occur due to thermal shock, thermal expansion/contraction, moisture absorption, deformation due to heat treatment, etc. Therefore, a problem arises in that peeling or cracking occurring at the fillet portion or the bump joint portion greatly affects connection reliability between the bump joint portions.

Additionally, the solder that forms the bumps has been replaced with lead-free solder. Therefore, as the reflow temperature during mounting becomes higher, thermal stress increases. Compared to eutectic solder, lead-free solder has inferior mechanical strength. In addition, the adoption of copper pillar bumps reduces the volume of lead-free solder applied. Therefore, the mechanical strength is further reduced.

From the above, conventional underfill materials have the problem that peeling or cracking at the fillet portion and peeling or cracking at the bump joint portion are likely to occur.

Further, as the number of bumps increases, the bump pitch and bump height become smaller. As a result, the gap is becoming narrower. Furthermore, with the trend towards higher integration, larger chips are being used. Therefore, the underfill material (CUF) is required to have the property of being able to flow over a large area even in a narrow gap.

In order to deal with such problems, attempts have been made to reduce the stress and increase the toughness of the underfill material (CUF) (see Patent Document 1).

Japanese Patent Application Publication No. 2013-163747

Nowadays, with regard to underfill materials, it is increasingly required to suppress the occurrence of cracks in the fillet portions described above. In other words, there is a need for an underfill material with excellent fillet crack resistance.
Conventional techniques cannot sufficiently satisfy the above required characteristics. Therefore, further improvements were required.

The present disclosure aims to provide a resin composition used as an underfill material (CUF) that has better fillet crack resistance in order to address the problems in the prior art described above. Further, the present disclosure aims to provide a semiconductor device using the resin composition, a method for manufacturing the semiconductor device, and a method for manufacturing the resin composition.

In order to achieve the above object, the resin composition according to the present embodiment,
(A) epoxy resin,
(B) a curing agent;
(C) A resin composition comprising a filler,
The cured product of the resin composition has a fatigue crack propagation lower limit stress intensity factor range ΔK _th of 0.55 MPa·m ^0.5 or more.

It is preferable that the resin composition according to this embodiment has a glass transition temperature (Tg) of a cured product of 100° C. or higher.

In the resin composition according to the present embodiment, the epoxy resin (A) preferably includes a liquid epoxy resin.

In the resin composition according to the present embodiment, the epoxy resin (A) is a group consisting of a bisphenol F type epoxy resin, a bisphenol A type epoxy resin, an aminophenol type epoxy resin, a naphthalene type epoxy resin, and a cyclohexane type epoxy resin. It is preferable to include at least one selected from the following.

In the resin composition according to the present embodiment, the content of the filler (C) is preferably 40 to 80 parts by weight based on 100 parts by weight of the total weight of all components of the resin composition.

In the resin composition according to the present embodiment, it is preferable that the filler (C) has an average particle size of 0.1 to 20.0 μm.

In the resin composition according to the present embodiment, the filler (C) is preferably surface-treated with a silane coupling agent.

The resin composition according to the present embodiment may further include (D) core-shell rubber.

In the resin composition according to this embodiment, the cured product preferably satisfies Requirement 1 described below.

In the resin composition according to the present embodiment, the cured product preferably satisfies Requirement 2 described below.

The semiconductor device according to the present embodiment includes a substrate, a semiconductor element disposed on the substrate, and a cured product of the resin composition according to the present embodiment that seals the semiconductor element.

A method for manufacturing a semiconductor device according to the present embodiment includes filling a gap between a substrate and a semiconductor element disposed on the substrate with the resin composition according to the present embodiment; and curing.

The method for producing a resin composition according to the present embodiment is a method for producing the resin composition, in which the (A) epoxy resin, the (B) curing agent, and the (C) filler are mixed using a roll mill. The method for producing a resin composition according to an embodiment includes producing a resin composition by mixing, and the pressure between the rolls of the roll mill is 3.0 MPa or more.

The underfill material (CUF) using the resin composition according to this embodiment has better fillet crack resistance.

FIG. 1 is a top view of a test piece used to measure the lower limit stress intensity factor range ΔK _th for fatigue crack propagation. FIG. 2 is a diagram for explaining a method of image analysis of a cross section of a test piece.

Hereinafter, the resin composition according to this embodiment will be explained in detail.
The resin composition according to this embodiment contains the following components (A) to (C) as essential components.

(A) Epoxy resin The epoxy resin of component (A) is a component that forms the main ingredient of the resin composition according to the present embodiment.
The epoxy resin of component (A) preferably includes a liquid epoxy resin that is liquid at room temperature (25° C.) from the viewpoint of viscosity, injectability, and the like. An epoxy resin that is solid at room temperature but exhibits a liquid state as a mixture when used in combination with a liquid epoxy resin can be suitably used.

Examples of the epoxy resin of component (A) include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, bixylenol type epoxy resin, cyclohexane type epoxy resin, and dicyclopentadiene type. Epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, having an aromatic structure Glycidylamine type epoxy resin, glycidyl ester type epoxy resin with an aromatic structure, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin with an aromatic structure, epoxy with a butadiene structure with an aromatic structure Resin, alicyclic epoxy resin with aromatic structure, heterocyclic epoxy resin, spiro ring-containing epoxy resin with aromatic structure, cyclohexanedimethanol type epoxy resin with aromatic structure, naphthylene ether type epoxy resin, aromatic Examples include trimethylol type epoxy resins, tetraphenylmethane type epoxy resins, aminophenol type epoxy resins, and silicone-modified epoxy resins having a group structure.

The epoxy resin of component (A) is preferably at least one selected from the group consisting of bisphenol F type epoxy resin, bisphenol A type epoxy resin, aminophenol type epoxy resin, naphthalene type epoxy resin, and cyclohexane type epoxy resin. It is made of two resins.

Specific examples of liquid epoxy resins include "YDF8170" (bisphenol F type epoxy resin), "YDF8125" (bisphenol A type epoxy resin), "ZX1658", and "ZX1658GS" (liquid 1) manufactured by Nippon Steel Chemical & Materials. , 4-glycidylcyclohexane), DIC's "HP-4032", "HP-4032D", "HP-4032SS" (naphthalene type epoxy resin), Mitsubishi Chemical's "jER828US", "jER828EL" (bisphenol A type epoxy resin), "jER806", "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), "jER630", "jER630LSD" (aminophenol type epoxy resin), "YX7400" ( high resilience epoxy resin), “ZX1059” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. (mixture product of bisphenol A type epoxy resin and bisphenol F type epoxy resin), “EX-721” manufactured by Nagase ChemteX (glycidyl ester type epoxy resin) ), and "Celoxide 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by Daicel Corporation.

Specific examples of solid epoxy resins include "HP-4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), and "N- 690” (cresol novolac type epoxy resin), “N-695” (cresol novolac type epoxy resin), “HP-7200”, “HP-7200L”, “HP-7200HH”, “HP-7200H”, “HP- 7200HHH” (dicyclopentadiene type epoxy resin), “EXA7311”, “EXA7311-G3”, “EXA7311-G4”, “EXA7311-G4S”, “HP6000” (naphthylene ether type epoxy resin), manufactured by Nippon Kayaku Co., Ltd. "EPPN-502H" (trisphenol type epoxy resin), "NC-7000-L" (naphthol novolak type epoxy resin), "NC-3000-H", "NC-3000", "NC-3000-L" , "NC-3100" (biphenyl type epoxy resin), "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical & Materials, "ESN485" (naphthol novolac type epoxy resin), "YX4000H" manufactured by Mitsubishi Chemical Corporation , "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YL7760" (bisphenol AF type epoxy resin), "YX8800" (anthracene type epoxy resin), " PG-100'', ``CG-500'', Mitsubishi Chemical's ``YL7800'' (fluorene type epoxy resin), Mitsubishi Chemical's ``jER1010'' (solid bisphenol A type epoxy resin), ``jER1031S'' (tetraphenyl ethane type epoxy resin), "jER157S70" (bisphenol novolac type epoxy resin), Mitsubishi Chemical's "YX4000HK" (bixylenol type epoxy resin), "YX8800" (anthracene type epoxy resin), Osaka Gas Chemical's " PG-100'', ``CG-500'', ``YL7800'' (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, and ``jER1031S'' (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Corporation.

The epoxy resin of component (A) can be used alone. Alternatively, two or more types of epoxy resins may be used in combination.
The blending amount of the epoxy resin as component (A) is preferably 5 to 50 parts by weight, more preferably 10 to 45 parts by weight, based on 100 parts by weight of the total weight of all components of the resin composition.

(B) Curing Agent The curing agent of component (B) is not particularly limited as long as it is an epoxy resin curing agent. Known curing agents can be used. Examples of the curing agent of component (B) include amine curing agents, acid anhydride curing agents, phenol curing agents, hydrazide curing agents, polymercaptan curing agents, Lewis acid-amine complexes, and the like.
The curing agent of component (B) is preferably at least one curing agent selected from the group consisting of amine curing agents, acid anhydride curing agents, and phenolic curing agents.

Examples of amine curing agents include aliphatic amines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, trimethylhexamethylenediamine, m-xylenediamine, and 2-methylpentamethylenediamine, isophoronediamine, 1,3 - Cycloaliphatic polyamines such as bisaminomethylcyclohexane, bis(4-aminocyclohexyl)methane, norbornenediamine, and 1,2-diaminocyclohexane, N-aminoethylpiperazine, and 1,4-bis(2-amino-2 - piperazine-type heterocycloaliphatic amines such as (methylpropyl)piperazine, as well as diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, diethyltoluenediamine, dimethylthiotoluenediamine, trimethylenebis(4-aminobenzoate), polytetra Aromatic amines such as methylene oxide-di-p-aminobenzoate and 4,4'-diamino-3,3'-diethyldiphenylmethane are mentioned.
Among these, 4,4'-diamino-3,3'-diethyldiphenylmethane, diethyltoluenediamine, and dimethylthiotoluenediamine are preferred.

The acid anhydride curing agent is not particularly limited. Examples of acid anhydride curing agents include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, arakylated tetrahydrophthalic anhydride, methylhimic anhydride, and succinic anhydride substituted with an alkenyl group. , and glutaric anhydride.
In particular, 3,4-dimethyl-6-(2-methyl-1-propenyl)-4-cyclohexene-1,2-dicarboxylic anhydride, 3,4-dimethyl-6-(2-methyl-1-propenyl) -1,2,3,6-tetrahydrophthalic anhydride, 1-isopropyl-4-methyl-bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, norbornane-2, Preferred are 3-dicarboxylic anhydride, methylnorbornane-2,3-dicarboxylic anhydride, hydrogenated methylnadic anhydride, alkenyl group-substituted succinic anhydride, and diethylglutaric anhydride.

Phenolic curing agents refer to monomers, oligomers, and polymers in general that have phenolic hydroxyl groups. Examples of phenolic curing agents include phenol novolak resins and their alkylated or allylated products, cresol novolak resins, phenol aralkyl (including phenylene and biphenylene skeletons) resins, naphthol aralkyl resins, triphenolmethane resins, and dicyclopentadiene type resins. Examples include phenolic resins. Among these, allylphenol novolak resin is preferred.

The curing agent of component (B) can be used alone. Alternatively, two or more types of curing agents may be used together.

The stoichiometric equivalent ratio (curing agent equivalent/epoxy group equivalent) of the curing agent of component (B) and the epoxy resin of component (A) is preferably 0.5 to 1.5, more preferably The curing agent of component (B) is blended so that the hardening agent has a hardening ratio of 0.8 to 1.2.
In addition, when the curing agent is a compound having active hydrogen such as an amine-based curing agent, the ratio of the active hydrogen equivalent of the curing agent to the epoxy equivalent of the epoxy resin (active hydrogen equivalent/epoxy equivalent) is preferably within the above range. be.

(C) Filler The filler of component (C) is not particularly limited as long as its addition has the effect of lowering the coefficient of linear expansion.
Examples of fillers of component (C) include silica (silicon dioxide) fillers, alumina (aluminum oxide) fillers, and aluminum nitride fillers. In particular, silica (silicon dioxide) filler is preferred because it can increase the amount of filler.
The filler of component (C) may be surface-treated with, for example, a silane coupling agent.

The average particle size of the filler of component (C) is preferably 0.1 to 20.0 μm, more preferably 0.3 to 10.0 μm.
Note that two or more types of fillers having different average particle sizes may be used in combination for the purpose of adjusting the viscosity of the resin composition according to the present embodiment.

The shape of the filler of component (C) is not particularly limited. The shape of the filler of component (C) may be spherical, amorphous, scaly, or the like.
The filler of component (C) can be used alone. Alternatively, two or more types of fillers may be used in combination.
The amount of the filler as component (C) is preferably 40 to 80 parts by weight, more preferably 40 to 75 parts by weight, based on 100 parts by weight of the total weight of all components of the resin composition.

In addition to the above-mentioned components (A) to (C), the resin composition according to the present embodiment may contain the following components as necessary.

(D): Core-shell rubber The resin composition according to this embodiment may contain core-shell rubber as component (D).
In the resin composition according to the present embodiment, the core-shell rubber as component (D) is used for the purpose of suppressing the occurrence and propagation of fillet cracks when the resin composition is used as an underfill material (CUF).
Specifically, when the resin composition according to this embodiment is used as an underfill material (CUF), the elastic modulus decreases due to the inclusion of component (D) (core shell rubber). This reduces the stress generated in the fillet portion. Therefore, generation of fillet cracks can be suppressed.
Furthermore, when fillet cracks occur, the core-shell rubber as component (D) acts as a stress reliever. Therefore, the development of fillet cracks can be suppressed.

In this specification, core-shell rubber refers to a rubber material with a multilayer structure composed of rubber particles forming a core and one or more shell layers covering the rubber particles. As will be described later, the core portion of the core-shell rubber can be made of a material with excellent flexibility. At the same time, the shell layer of the core-shell rubber can be made of a material that has excellent affinity for components other than component (D) contained in the resin composition, particularly the epoxy resin as component (A). Thereby, it is possible to achieve good dispersibility in the resin composition while achieving a low elastic modulus by blending the rubber component.

A material with excellent flexibility is used as the constituent material of the rubber particles forming the core part. Examples of this constituent material include silicone rubber, butadiene rubber, styrene rubber, acrylic rubber, polyolefin rubber, and silicone/acrylic composite rubber.

On the other hand, as the constituent material of the shell layer, a material having excellent affinity for other components other than component (D) contained in the resin composition according to the present embodiment, especially the epoxy resin as component (A) is used. used.
Examples of this constituent material include acrylic resins and epoxy resins such as bisphenol A epoxy resins and bisphenol F epoxy resins.

Specific examples of core-shell rubber include "Kane Ace MX-153", "Kane Ace MX-257", "Kane Ace MX-154", "Kane Ace MX-960", "Kane Ace MX-136", and "Kane Ace MX-153" manufactured by Kaneka Corporation. MX-137'', ``Kane Ace MX-965'', ``Kane Ace MX-217'', ``Kane Ace MX-227M75'', ``Kane Ace MX-334M75'', ``Kane Ace MX-416'', and ``Kane Ace MX-451'', Mitsubishi Chemical “Metablen C-223A”, “Metablen C-140A”, “Metablen E-860A”, “Metablen E-870A”, “Metablen E-875A”, “Metablen S-2100”, “Metablen S-” manufactured by Co., Ltd. 2200'', and ``Metablen S-2260'', ``Staphyloid IM-203'', ``Staphyloid IM-401'', ``Staphyloid IM-601'', ``Staphyloid AC3355'', and ``Staphyloid IM-203'' manufactured by Aica Kogyo Co., Ltd. Lloyd's AC3816'', as well as Nippon Shokubai Co., Ltd.'s ``Acriset BPA328'' and ``Acriset BPF307''. In particular, silicone-based and butadiene-based cores are preferably used from the viewpoints of toughness, heat resistance, durability, and crack resistance.

Component (D), the core-shell rubber, can be used alone. Alternatively, two or more types of core shell rubbers may be used in combination.
The blending amount of the core shell rubber of component (D) is preferably 0.3 to 10.0 parts by mass, more preferably 0.5 to 8.0 parts by mass, based on 100 parts by mass of the total mass of all components of the resin composition. Department.

(E): Curing accelerator The resin composition according to this embodiment may contain a curing accelerator as component (E).
The curing accelerator as component (E) is not particularly limited as long as it is a curing accelerator for epoxy resins. Known curing accelerators can be used.
The curing accelerator as component (E) imparts an appropriate curing speed to the epoxy resin as component (A).
Examples of curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl-4-methylimidazole. It will be done. Examples of commercially available products include 2-phenyl-4-methylimidazole (manufactured by Shikoku Kasei Co., Ltd., trade name: 2P4MZ), and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl. -s-triazine (manufactured by Shikoku Kasei Co., Ltd., trade name: 2MZA).
Alternatively, encapsulated imidazole called microcapsule imidazole or epoxy adduct imidazole may be used. Examples of encapsulated imidazoles include HX3941HP, HXA3942HP, HXA3922HP, HXA3792, HX3748, HX3721, HX3722, HX3088, HX3741, HX3742, and HX3613 (all manufactured by Asahi Kasei Chemicals, trade names), PN-23J , PN-40J, and Examples include PN-50 (manufactured by Ajinomoto Fine Techno Co., Ltd., trade name) and FXR-1121 (manufactured by Fuji Kasei Kogyo Co., Ltd., trade name).
Component (E), a curing accelerator, can be used alone. Alternatively, two or more types of curing accelerators may be used in combination.
The blending amount of the curing accelerator as component (E) is preferably 0.1 to 5.0 parts by mass, more preferably 0.2 to 3.0 parts by mass, based on 100 parts by mass of the total mass of all components of the resin composition. Part by mass.

(Other combination agents)
The resin composition according to the present embodiment may further contain components other than the above-mentioned components (A) to (E) as other compounding agents, if necessary. Examples of such additives include coupling agents, ion trapping agents, leveling agents, antioxidants, antifoaming agents, flame retardants, colorants, and reactive diluents. The amount of each compounding agent can be determined according to a conventional method.

Examples of coupling agents include silane coupling agents such as vinyl-based, glycidoxy-based, methacrylic-based, amino-based, mercapto-based, and imidazole-based, titanium coupling agents such as alkoxide-based, chelate-based, and acylate-based, and , glycidoxyoctyltrimethoxysilane, and methacrylooctyltrimethoxysilane.
The above coupling agents can be used alone. Alternatively, two or more types of coupling agents may be used in combination.

(Preparation of resin composition)
The resin composition according to this embodiment can be manufactured by a conventional method.
For example, the resin composition is prepared by mixing components (A) to (C) and, if necessary, component (D), component (E), or the other compounding agents mentioned above.
When the epoxy resin of component (A) is solid, preferably component (A) liquefied or fluidized by heating or the like is mixed with other components. If it is difficult to uniformly disperse the filler of component (C) in the epoxy resin of component (A), the epoxy resin of component (A) and the filler of component (C) may be mixed first. The remaining ingredients may then be mixed in later.
When mixing each component, each component can be mixed simultaneously. Alternatively, some of the components may be mixed first, and then the remaining components may be mixed later.
The method of mixing components (A) to (C) is not particularly limited. A known mixing method can be employed. Among these, a roll mill is preferably used from the viewpoint of easy adjustment of ΔK _th , which will be described later. That is, components (A) to (C), and if necessary, component (D), component (E), and the other ingredients mentioned above are mixed using a roll mill. In this way, the resin composition can be suitably manufactured.
The roll mill is preferably composed of three or more rolls.
The inter-roll pressure in the roll mill is not particularly limited. The inter-roll pressure is preferably 2 MPa or more, more preferably 3 MPa or more, since ΔK _th can be easily adjusted within a predetermined range. The upper limit of the pressure between the rolls is not particularly limited. In many cases, the upper limit of the inter-roll pressure is 30 MPa or less. More often, the upper limit of the inter-roll pressure is 20 MPa or less.

The characteristics of the resin composition according to this embodiment will be described below.
(Fatigue crack propagation lower limit stress intensity factor range ΔK _th )
The fatigue crack propagation lower limit stress intensity factor range ΔK _th is known as an index for fatigue crack propagation performance evaluation (A study on a simple identification method for the lower limit stress intensity factor range ΔK _th , Koji Murakami, Koji Goto, Welding Proceedings of the Society, Volume 35, No. 4, p149-153 (2017), Japanese Patent Application Laid-Open No. 6-82353).

In the fatigue crack propagation test, the crack propagation speed da/dN, which is determined from the relationship between the number of repeated loads N and the crack length a, is given as a function of the stress intensity factor width ΔK.
Note that the stress intensity factor K is expressed by the following equation.
K=f(a/W)σ(πa) ^1/2
Here, W is the width of the test piece, a is the crack length, σ is the applied stress, and f is a constant determined by the ratio of a to W.
Note that the above f is specifically calculated by the following formula.

A fatigue crack growth test can be conducted according to the procedure described below. Plotting the relationship between the crack propagation speed da/dN obtained from the test results and the stress intensity factor width ΔK shows that when the stress intensity factor width ΔK is below a certain value, the crack propagation speed da/dN becomes 0, and fatigue cracks It is recognized that it does not grow. This specific value is usually defined as the fatigue crack propagation lower limit stress intensity factor range ΔK _th . When the stress intensity factor width ΔK is greater than or equal to the lower limit stress intensity factor range ΔK _th for fatigue crack propagation, the crack propagation speed da/dN increases as the stress intensity factor width ΔK increases. At this time, the relationship between logda/dN and logΔK is approximately a straight line. It is known that the Paris law expressed by the following equation holds regarding this relationship.
da/dN=C・ΔK'
However, in the present disclosure, ΔK when da/dN=1.0×10 ⁻⁹ m/cycle is defined as fatigue crack propagation lower limit stress intensity factor range ΔK _th .

The fatigue crack propagation lower limit stress intensity factor range ΔK _th of the cured product of the resin composition according to the present embodiment is 0.55 MPa·m ^0.5 or more. When ΔK _th is 0.55 MPa·m ^0.5 or more, fillet crack resistance is improved. Among these, ΔK _th is preferably 0.56 MPa·m ^0.5 or more, more preferably 0.60 MPa·m ^0.5 or more. The upper limit of ΔK _th is not particularly limited. In many cases, the upper limit is 0.9 MPa·m ^0.5 or less. More often this upper limit is less than or equal to 0.8 MPa·m ^0.5 .
ΔK _th can be adjusted, for example, using the items described in (1) to (5) below. Note that ΔK _th can be adjusted using only one of the following (1) to (5). Alternatively, ΔK _th can be adjusted using two or more items in combination.

(1) Glass transition temperature (Tg) of cured product of resin composition
ΔK _th can be adjusted by the glass transition temperature (Tg) of the cured product of the resin composition. The lower the glass transition temperature (Tg) of the cured product of the resin composition described below, the larger the ΔK _th tends to be (for example, see Examples 1 and 6 described below). As the Tg decreases, the crosslinking density of the resin skeleton decreases. This increases flexibility. As a result, the stress applied to the cured product of the resin composition can be more relaxed. It is considered that ΔK _th can be increased in this way.
The preferred range of the glass transition temperature (Tg) of the cured product of the resin composition will be described later.

(2) Amount of component (C) filler ΔK _th can be adjusted by adjusting the amount of component (C) filler blended. There is a tendency for ΔK _th to increase as the amount of the filler of component (C) increases (for example, see Example 1 and Example 2 described below). By incorporating a large amount of filler, the elastic modulus and strength of the cured product of the resin composition are improved. Therefore, the energy required for crack growth per unit area increases. It is considered that ΔK _th can be increased in this way.

(3) Blending of core-shell rubber as component (D) ΔK _th can also be adjusted by blending the core-shell rubber as component (D). When the core-shell rubber of component (D) is blended, ΔK _th tends to increase (for example, see Examples 4 and 9 below). It is considered that ΔK _th can be increased by the core-shell rubber relaxing the stress applied to the cured product of the resin composition.

(4) Use of an epoxy resin with a flexible skeleton as the epoxy resin of component (A) ΔK _th can also be adjusted by using an epoxy resin with a flexible skeleton as the epoxy resin of component (A). When an epoxy resin having a flexible skeleton is used as the epoxy resin of component (A), ΔK _th tends to increase (for example, see Example 1 and Example 7 described below). It is thought that ΔK _th can be increased by the flexible skeleton in the epoxy resin relaxing the stress applied to the cured product of the resin composition.
Here, the flexible skeleton refers to a molecular skeleton, such as an alkyl chain or a siloxane, that has a structure that allows easy movement. Examples of epoxy resins having flexible skeletons include (poly)ethylene glycol-modified epoxy resins, (poly)propylene glycol-modified epoxy resins, (poly)tetramethylene glycol-modified epoxy resins, and (poly)hexamethylene glycol-modified epoxy resins. Examples include (poly)alkylene glycol-modified epoxy resins. Other examples include epoxy resins having a siloxane skeleton such as bis(2-(3,4-epoxycyclohexyl)ethyl)polydimethylsiloxane and polydimethylsiloxane diglycidyl ether, and polyisobutylene diglycidyl ether. .

(5) Uniformity of the resin composition ΔK _th can also be adjusted by the uniformity of the composition in the resin composition. When kneading a resin composition under strong pressure using a three-roll mill, ΔK _th tends to increase (for example, see Example 3 and Comparative Example 5 described below). If the composition in the resin composition is non-uniform, stress will be concentrated at one location in the cured product of the resin composition. And cracks tend to grow from that part. By making the composition uniform in the resin composition, stress is evenly propagated inside the cured product of the resin composition. It is believed that in this way, the strength of the cured product of the resin composition can be maximized.

When measuring the above ΔK _th , first, a curing treatment is performed on the resin composition according to the present embodiment. A test piece is thereby obtained. In the curing treatment, the applied resin composition is heat treated at 165° C. for 2 hours.
A test piece is produced by the above heat treatment. The size of the test piece is 20 mm (L) x 2 mm (W) x 0.5 mm (T). A crack (length 0.3 mm) was prepared in advance in the test piece. More specifically, FIG. 1 is a top view of the test piece 10. In FIG. 1, a surface consisting of a length L and a width W is observed. As shown in FIG. 1, a crack 12 is created in the center of the length L of the test piece 10, extending from one side toward the other side. The direction in which the cracks 12 extend is parallel to the width direction of the test piece 10. The crack 12 is created so as to penetrate the test piece in the thickness direction. Note that stress is applied to the test piece in the direction indicated by the arrow in the test described below.
A microload tester (LMH207-10 manufactured by Saginomiya Seisakusho) is used to apply repeated loads (stress). A microscope (SZX-16 manufactured by Olympus) and a long-term video/still image (time-lapse) acquisition system are used for crack observation. The load waveform produced by the microload tester is a sine wave. Its frequency is 2Hz. However, due to the characteristics of the lower limit stress intensity factor range ΔK _th for fatigue crack propagation, the test is preferably conducted at low stress in order to confirm crack propagation behavior under minute stress. Then, the test stress is gradually increased only when the crack does not propagate.
Therefore, in the test, first, the value of The specimen is repeatedly loaded while changing the load. In this way, the value of X at which a crack of 1 μm or more does not grow after 20,000 cycles is found. Next, a load is repeatedly applied to the test piece each time the value of X is increased by 0.1N from the value of X found above. Then, among the values of X when a crack of 1 μm or more grows after 20,000 cycles, the minimum value (hereinafter also referred to as "value Y") is determined.
For example, first, under the above loading conditions, a repeated load is applied to the test piece with a maximum stress X of 14 (N). If a crack of 1 μm or more does not develop after 20,000 cycles, then the maximum stress Can be applied to. After 20,000 cycles, it is confirmed whether or not cracks of 1 μm or more have grown. If the crack has not developed, a similar test is conducted with the maximum stress X of 14.2 (N), which is increased by 0.1 (N) from that value. In this way, the test is repeated with the maximum stress X increased by 0.1 (N) until the growth of a crack of 1 μm or more is confirmed after 20,000 cycles. Thereby, the minimum value Y of the maximum stress X can be determined.
Next, a load is repeatedly applied to the test piece under the condition that the above-mentioned X is the value Y. At this time, the growth of cracks is confirmed on the surface consisting of the length L and width W of the test piece. The length Lc of this crack (see FIG. 1) is measured. Then, the relationship between the crack propagation speed da/dN and the stress intensity factor width ΔK is plotted. Here, ΔK when da/dN=1.0×10 ⁻⁹ m/cycle is defined as ΔK _th .
Note that the stress intensity factor range ΔK corresponds to the difference between the maximum value ΔK _max and the minimum value ΔK _min of the stress intensity factor K during one cycle. Here, in the above measurement, the minimum stress value ΔK _min during one cycle is 0. From this, the relationship ΔK=ΔK _max is obtained.

(Glass transition temperature (Tg))
The glass transition temperature (Tg) of the cured product of the resin composition according to this embodiment is preferably 100°C or higher. The underfill material desirably has good bump crack resistance in addition to good fillet crack resistance. When Tg is 100° C. or higher, bump crack resistance improves. The Tg of the cured product of the resin composition according to this embodiment is more preferably 103°C or higher, and even more preferably 105°C or higher. The upper limit of Tg of the cured product of the resin composition according to the present embodiment is not particularly limited. In many cases, the upper limit of this Tg is 200°C or less. More often, the upper limit of this Tg is 180°C or less.
When measuring the glass transition temperature, first, a test piece is obtained by curing the resin composition according to the present embodiment. As for the curing treatment, the applied resin composition is heat treated at 165° C. for 2 hours. In addition, the film thickness of the obtained cured product is adjusted to be in the range of 2000±100 μm.
Next, the glass transition temperature of the obtained cured product was measured using a dynamic thermomechanical measuring device (DMA) under the conditions of -20 to 260°C, frequency of 1Hz, and temperature increase rate of 3°C/min. It can be determined by the double-sided bending method. The glass transition temperature (Tg) is determined from the peak temperature of the loss tangent (tan δ) determined from the loss modulus (E'')/storage modulus (E').

(viscosity)
The resin composition according to this embodiment has low viscosity. Therefore, when the resin composition is used as an underfill material (CUF), the injectability by capillary flow is good.
Specifically, the viscosity when measured using a rotational viscometer at 25° C. and a rotation speed of 50 rpm is preferably 100 Pa·s or less, more preferably 80 Pa·s or less. The lower limit is not particularly limited. In many cases, the lower limit is 1 Pa·s or more. In more cases, the lower limit is 10 Pa·s or more.

(Requirement 1)
The cured product of the resin composition according to this embodiment preferably satisfies the following requirement 1.
Requirement 1: In the cross section of the cured product of the resin composition, the area (μm ² ) occupied by the filler is calculated in each of six randomly selected areas of 37.8 μm in width x 18.9 μm in length. In this case, the standard deviation of the area (filler area) of each of the six fillers obtained is 0.36 μm ² or less. Here, the filler area is obtained by observing the cross section of the cured product of the resin composition at a magnification of 1000 times using a scanning electron microscope.
Requirement 1 will be explained in detail below.

In requirement 1, the standard deviation of the filler area in the cross section of the cured product of the resin composition is calculated. The smaller the value of this standard deviation, the more uniform the size and/or distribution of the filler contained in the resin composition. In other words, a small standard deviation means that the composition of the resin composition is highly uniform. That is, the standard deviation is related to the above-mentioned (5) uniformity of the resin composition. Therefore, the smaller the standard deviation calculated under requirement 1, the larger ΔK _th becomes. The standard deviation calculated under requirement 1 is preferably 0.36 μm ² or less, more preferably 0.27 μm ² or less. The lower limit of the standard deviation is not particularly limited. In many cases, this standard deviation is greater than or equal to 0 μm ² . More often this standard deviation is 0.02 μm ² or more.
Hereinafter, an example of a method for calculating the standard deviation of the area occupied by the filler under Requirement 1 will be described in detail.

First, a test piece is obtained by curing the resin composition according to the present embodiment. Specifically, first, a glass plate is fixed onto an organic substrate (FR-4 substrate) with a gap of 100 μm in between. Then, the organic substrate having the fixed glass plate is placed on a hot plate set at 110°C. Then, the resin composition according to this embodiment is injected into the gap. The injection width is 10 mm. The injection length is 20 mm. Thereafter, as a curing treatment, the injected resin composition is heat treated at 165° C. for 2 hours.
Next, the obtained test piece (cured product of the resin composition) is cut. Then, an exposed cross section is observed at an injection distance of 10 mm. A scanning electron microscope (Hitachi Scanning Electron Microscope System S-3400N) is used for observation. The observation magnification is 1000 times. Further, the size of the image at the time of observation is 122.4 μm in width and 93.4 μm in height. The resolution is 1280x960.
Next, the obtained observation image is analyzed using image analysis software WinROOF2018 (Mitani Shoji Co., Ltd., Ver. 4.5.5). The range of image analysis is a range of 113.4 μm horizontally and 37.8 μm vertically in the acquired observation image. The number of pixels is 1200×400. As a specific procedure for image analysis, in order to reduce noise, a cross-sectional observation image of the cured product is filtered using a median filter (5×5 pixels) using the above software. Furthermore, the observed image is subjected to monochrome image processing and then to binarization processing. In the binarization process, images having shading less than a predetermined threshold are cut off. The image is processed by setting an image having a density equal to or greater than a threshold value to 1, and an image having a density less than the threshold value to a value 0. Binarization is performed using Otsu's method (discriminant analysis method).
Next, the filler area (μm ² ) in a region of 37.8 μm horizontally×18.9 μm vertically in the binarized observed image is calculated. The area of 37.8 μm in width x 18.9 μm in height is an area of 400 x 200 pixels in the binarized observation image 20 in FIG. 2 (indicated as A in FIG. 2). area). Specifically, the number of pixels included in the filler in one region selected from regions A to F in FIG. 2 is calculated. Then, the number of pixels is multiplied by the area of one pixel. The obtained value is defined as the filler area. The filler area within each selected region is determined by the above procedure. Furthermore, the average value of these six filler areas is calculated. The calculated average value is defined as the average area (μm ² ) of the filler.
Through the above processing, the filler area in each of the six regions (areas indicated by A to F in FIG. 2) in the binarized observed image 20 shown in FIG. 2 is calculated. Using the obtained six filler area values, the standard deviation thereof is calculated. If the obtained value is 0.36 μm ² or less, requirement 1 is fulfilled.
In the above, when the standard deviation is calculated, a range wider than the area of 37.8 μm horizontally×18.9 μm vertically is subjected to the binarization process. However, the area itself, which is 37.8 μm wide by 18.9 μm high and selected from the areas A to F, may be subjected to the binarization process. Thereafter, the filler area of the selected region may be calculated by the above process. The standard deviation can also be determined by performing such processing for six different locations.
Furthermore, the six randomly selected areas corresponding to the standard deviation determined above mean six areas that do not overlap with each other.
Note that the number of pixels included in the filler in each region of 37.8 μm horizontally×18.9 μm vertically can be calculated. Then, the standard deviation of the number of pixels included in the filler in each area (hereinafter also referred to as "standard deviation of the number of pixels") can be calculated. In this case, the standard deviation of the number of pixels is preferably 40 or less pixels. The lower limit of the standard deviation of the number of pixels is not particularly limited. For example, the lower limit is 0 pixels.

(Requirement 2)
The cured product of the resin composition according to this embodiment preferably satisfies Requirement 2 below.
Requirement 2: In the cross section of the cured product of the resin composition, when calculating the number of fillers in each of six randomly selected areas of 37.8 μm in width x 18.9 μm in length, The standard deviation of the number of six fillers determined is 80 or less. Here, the number of fillers can be obtained by observing the cross section of the cured product of the resin composition at a magnification of 1000 times using a scanning electron microscope.
Requirement 2 will be explained in detail below.

In requirement 2, the standard deviation of the number of fillers in the cross section of the cured product of the resin composition is calculated. The smaller the value of this standard deviation, the higher the uniformity of the composition of the resin composition. That is, this standard deviation is related to the above-mentioned (5) uniformity of the resin composition. Therefore, the smaller the standard deviation of Requirement 2, the larger ΔK _th becomes. The standard deviation of requirement 2 is preferably 60 or less, more preferably 55 or less. The lower limit of the above standard deviation is not particularly limited. In many cases, this standard deviation is 0 or more. More often this standard deviation is 5 or more.
Hereinafter, an example of a method for calculating the standard deviation of the number of fillers in a sub-region where fillers are located, which is Requirement 2, will be described in detail.

In calculating the standard deviation of Requirement 2, a binarized observed image is obtained in accordance with the same procedure as described in Requirement 1.
Next, the number of fillers in an area of 37.8 μm in width×18.9 μm in height in the binarized observed image is calculated.
Through the above processing, the number of fillers in each of the six regions (areas indicated by A to F in FIG. 2) in the binarized observed image 20 shown in FIG. 2 is calculated. Using the obtained values of the numbers of the six fillers, the standard deviation thereof is calculated. If the obtained values are 80 or less, Requirement 2 is satisfied.
In the above, when the standard deviation is calculated, an observed image wider than an area of 37.8 μm in width×18.9 μm in height is binarized. However, a region of 37.8 μm in width x 18.9 μm in height selected from regions A to F may itself be subjected to the binarization process. Thereafter, the number of fillers in the selected area may be calculated by the above process. The standard deviation may be determined by performing such processing for six different locations.
Further, the six randomly selected regions corresponding to the standard deviation determined above mean six regions whose regions do not overlap with each other.

The semiconductor device according to the present embodiment is a semiconductor device including a substrate, a semiconductor element disposed on the substrate, and a cured product of the resin composition according to the present embodiment sealing the semiconductor element. .
The semiconductor element is not particularly limited. Examples of semiconductor devices include integrated circuits, large scale integrated circuits, transistors, thyristors, diodes, and capacitors.

A method for manufacturing a semiconductor device according to the present embodiment includes filling a gap between a substrate and a semiconductor element arranged on the substrate with the resin composition according to the present embodiment; and curing.

In filling the resin composition, for example, the resin composition according to the present embodiment is applied to one end of the semiconductor element while heating the substrate to 70 to 120°C. Then, the gap between the substrate and the semiconductor element is filled with the resin composition according to the present embodiment due to capillary action. At this time, the substrate may be tilted in order to shorten the time required for filling the resin composition according to the present embodiment. Alternatively, a pressure difference may be generated inside and outside the gap.

In curing the resin composition, after the gap is filled with the resin composition according to the present embodiment, the substrate is heated at a predetermined temperature for a predetermined time, for example, at 150 to 165° C. for 0.5 to 2 hours. Ru. In this way, the gap is sealed by heating and curing the resin composition.

Hereinafter, this embodiment will be described in detail using Examples. However, this embodiment is not limited to these examples.

(Examples 1 to 13, Comparative Examples 1 to 5)
The raw materials were kneaded using a roll mill (three-roll mill) at the blending ratios shown in the table below. In this way, the resin compositions of Examples 1 to 13 and Comparative Examples 1 to 5 were prepared. The pressure during roll mill kneading (pressure between rolls) was 3 MPa except for Comparative Example 5, and 1 MPa in Comparative Example 5. Note that the numerical values regarding each composition in the table represent parts by mass.

The ingredients used when preparing the resin composition are as follows.

Component (A): Epoxy resin Epoxy resin A-1: Liquid bisphenol F type epoxy resin, product name YDF8170, manufactured by Nippon Steel Chemical & Materials, epoxy equivalent 158 g/eqs
Epoxy resin A-2: Liquid aminophenol type epoxy resin, product name jER630, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 98 g/eq,
Epoxy resin A-3: Liquid naphthalene type epoxy resin, product name HP-4032D, manufactured by DIC, epoxy equivalent 140 g/eq
Epoxy resin A-4: Liquid cyclohexane type epoxy resin, product name EP-4085S, manufactured by ADEKA, epoxy equivalent 145 g/eq

Component (B): Curing agent Curing agent B-1: Amine curing agent, 4,4'-diamino-3,3'-diethyldiphenylmethane, product name HDAA, active hydrogen equivalent 63.5 g/eq, Nippon Kayakusha Curing agent B-2: Amine curing agent, diethyltoluenediamine, product name Ettacure 100, active hydrogen equivalent 44.5 g/eq, manufactured by Albemarle Curing agent B-3: Amine curing agent, dimethylthiotoluenediamine, product Etacure 300, active hydrogen equivalent 53.5g/eq, manufactured by Albemarle Hardening agent B-4: Acid anhydride hardening agent, 3,4-dimethyl-6-(2-methyl-1-propenyl)-4-cyclohexene -1,2-dicarboxylic acid anhydride, product name YH307, active hydrogen equivalent 117 g/eq, manufactured by Mitsubishi Chemical Corporation

Component (C): Filler Filler C-1: 3-glycidoxypropyltrimethoxysilane surface treatment silicon dioxide, average particle size 0.5 μm, product name SE2200-SEJ, manufactured by Admatex Filler C-2: silicon dioxide, Average particle size 0.5 μm, product name SO-E2, manufactured by Admatex Filler C-3: 3-glycidoxypropyltrimethoxysilane surface treatment silicon dioxide, average particle size 1.5 μm, product name SE5050-SEJ, Ad Filler C-4 manufactured by Matex: 3-glycidoxypropyltrimethoxysilane surface treated silicon dioxide, product name SE1050-SEO, average particle size 0.3 μm, manufactured by Admatex Filler C-5: Aluminum oxide, product name A9 -SX-E2, average particle size 10 μm, manufactured by Admatex

Component (D): Core shell rubber Core shell rubber D-1: Product name MX-137 (core shell type butadiene rubber particles, manufactured by Kaneka Corporation)
Core-shell rubber D-2: Product name MX-965 (core-shell type silicone rubber particles, manufactured by Kaneka Corporation)

Component (E): Curing accelerator Curing accelerator E-1: 2-phenyl-4-methylimidazole, product name 2P4MZ, manufactured by Shikoku Kasei Co., Ltd.

(viscosity)
Using a Brookfield viscometer, the viscosity (Pa·s) of the evaluation sample immediately after preparation was measured at a liquid temperature of 25° C. and 50 rpm.

(Tg)
Using a dynamic viscoelasticity apparatus, the storage modulus and loss modulus of the cured resin compositions of each Example and each Comparative Example were measured. The peak value of tan δ, which is the ratio of these elastic moduli, was measured as Tg. The above elastic modulus was measured according to Japanese Industrial Standard JIS C6481.
More specifically, first, spacers made of overlapping heat-resistant tape were placed at two locations on a Teflon (registered trademark) sheet attached to the surface of a 3 mm thick glass plate. At this time, the thickness of the spacer was adjusted so that the thickness of the cured resin composition, which will be described later, was 2000±100 μm. Next, a resin composition was applied onto the Teflon sheet between the spacers. The applied resin composition was sandwiched between another glass plate with a Teflon (registered trademark) sheet pasted on its surface, taking care not to entrap air bubbles. In this state, the resin composition was cured at 165°C for 2 hours. Finally, the cured product thus obtained was peeled off from the Teflon (registered trademark) sheet. Thereafter, the cured product was cut into a predetermined size (10 mm x 50 mm) using a cutting machine. In this way, a test piece was obtained. Note that the cut edges of the cut cured product were smoothed with sandpaper. The Tg of this test piece was measured using a dynamic thermomechanical measuring device (DMA) (manufactured by Hitachi High-Tech Science) under the conditions of -20 to 260°C, frequency of 1Hz, and temperature increase rate of 3°C/min. It was measured by the holding bending method. Tg was determined from the peak temperature (° C.) of tan δ determined from E''/E'.

( _ΔKth )
ΔK _th was determined by the following procedure.
A fatigue crack propagation test was conducted to determine the stress intensity factor width ΔK expressed by the following equation.
ΔK=f(a/W)σ(πa) ^1/2
W: width of the test piece, a: crack length, σ: applied stress, f: constant determined by the ratio of a and W.
The resin compositions of each example and comparative example were cured at 165° C. for 2 hours to prepare test pieces.
The size of the test piece was 20 mm (L) x 2 mm (W) x 0.5 mm (T). As explained in FIG. 1, a crack with a length of 0.3 mm was provided in the test piece. As the test device, a microload tester (LMH207-10 manufactured by Saginomiya Seisakusho) was used. A microscope (SZX-16 manufactured by Olympus) and a long-time video/still image (time-lapse) acquisition system were used for crack observation. The load waveform obtained by the microload tester was a sine wave. Its frequency was 2Hz.
Next, as mentioned above, under one cycle of loading conditions where the load waveform is a sine wave, the frequency is 2Hz, the minimum stress is 0 (N), and the maximum stress is X (N), calculate the value of X. The test was repeated with modifications. After 20,000 cycles of loading under the same loading conditions, the minimum value of X was determined when crack growth of 1 μm or more was observed in the test piece. By repeatedly applying a load to the test piece at the determined minimum value, the relationship between the obtained crack propagation speed da/dN and the stress intensity factor width ΔK was plotted. The obtained ΔK when da/dN=1.0×10 ⁻⁹ m/cycle was defined as ΔK _th .

(Reliability test)
The resin composition of each Example and Comparative Example was applied to a test piece mounted on a Walts-KIT FC150 01A150P-10 substrate manufactured by Walts Corporation and a silicon chip: Walts-TEG FC150JY. The applied resin composition was cured at 165° C. for 2 hours.
A preconditioning test was conducted under JEDEC Level 3 conditions. Thereafter, _{a thermal} cycle was performed under Condition B for 1000 cycles. Thereafter, the fillet portion was observed using a microscope to evaluate fillet crack resistance. In this way, the presence or absence of fillet cracks was observed. In addition, as an evaluation of bump crack resistance, the presence or absence of breakage of the daisy chain in the test piece was observed using a resistance meter. The reliability test was performed five times using different specimens.

In Tables 1 to 3, "filler addition amount" represents the filler content (parts by mass) relative to 100 parts by mass of the resin composition.
In Tables 1 to 3, "amount of rubber particles added" represents the content (parts by mass) of core shell rubber with respect to 100 parts by mass of the resin composition.
In Tables 1 to 3, "equivalent ratio" represents the ratio of the active hydrogen equivalent of the curing agent to the epoxy equivalent of the epoxy resin (active hydrogen equivalent/epoxy equivalent).
In Tables 1 to 3, "fillet cracks" represents the number of test pieces having fillet cracks observed in the above reliability test. For example, "0/5" means that fillet cracks were not observed in any of the test pieces when the reliability test described above was performed five times using different test pieces. "1/5" means that fillet cracks were observed in one test piece.
In Tables 1 to 3, "poor conduction (open)" represents the number of test pieces exhibiting daisy chain breakage observed in the above reliability test. For example, "0/5" means that when the reliability test described above was conducted five times using different test pieces, no breakage of the daisy chain was observed in any of the test pieces. "1/5" means that daisy chain breakage was observed in one test piece.
In Tables 1 to 3, "pressure between rolls (MPa)" represents the pressure between rolls (MPa) during roll milling.

No fillet cracks were observed in any of Examples 1 to 13 showing ΔK _th of 0.55 MPa·m ^0.5 or more. The frequency of wire breakage was less than 1 out of 5 times. No wire breakage was observed in any of Examples 1 to 7 and Examples 9 to 13, which had a Tg of 105° C. or higher.
In addition, in Examples 2 and 3, the filler blending ratio of Example 1 was changed.
In Example 4, two different epoxy resins (A) are used together.
In Examples 5 and 6, the equivalent ratio of the epoxy resin as component (A) and the curing agent as component (B) in Example 4 was changed.
In Example 7, unlike Example 4, epoxy resin A-4 was used in combination with epoxy resin A-1 as component (A) instead of epoxy resin A-2.
In Example 8, the equivalent ratio of the epoxy resin as component (A) and the curing agent as component (B) in Example 7 was changed.
In Example 9, two different epoxy resin components (A) are used together. Additionally, component (D), a core shell rubber, is added to the composition.
In Example 10, an epoxy resin different from that in Example 1 is used as component (A). Additionally, component (D), a core shell rubber, is added to the composition.
In Example 11, three different epoxy resins of component (A) are used together. Furthermore, two curing agents different from those in Example 1 are used as component (B).
In Example 12, a different curing agent from that in Example 1 is used as component (B). Furthermore, two fillers different from those in Example 1 are used together as component (C).
In Example 13, a curing agent different from that in Example 1 is used as component (B). Furthermore, a filler different from that in Example 1 is used as component (C).
Fillet cracks were observed in all of Comparative Examples 1 to 5 having ΔK _th of less than 0.55 MPa·m ^0.5 .

(Evaluation of requirement 1)
Evaluation of Requirement 1 was conducted using the resin compositions of Examples 3, 10, 12, and Comparative Example 5 according to the procedure shown below. Table 4 shows the results obtained.
For evaluation of Requirement 1, test pieces were first obtained by curing the resin compositions of Examples 3, 10, 12, and Comparative Example 5. Specifically, first, a glass plate was fixed onto an organic substrate (FR-4 substrate) with a gap of 100 μm in between. The organic substrate with the fixed glass plate was placed on a hot plate set at 110°C. Then, each of the resin compositions of Examples 3, 10, 12, and Comparative Example 5 was injected into the gap. The injection width was 10 mm. The injection length was 20 mm. Thereafter, as a curing treatment, the injected resin composition was heat-treated at 165° C. for 2 hours.
The obtained test piece (cured product of the resin composition) was cut. An exposed cross section was observed at an injection distance of 10 mm. A scanning electron microscope (Hitachi Scanning Electron Microscope System S-3400N) was used for the observation. The observation magnification was 1000 times. Further, the size of the image at the time of observation was 122.4 μm in width and 93.4 μm in height. The resolution was 1280x960.
Next, the obtained observation images were analyzed using image analysis software WinROOF2018 (Mitani Shoji Co., Ltd., Ver. 4.5.5). The range of image analysis was a range of 113.4 μm horizontally and 37.8 μm vertically in the obtained observation image. The number of pixels was 1200×400. The specific procedure for image analysis is that the cross-sectional observation image of the cured product is filtered with a median filter (5 x 5 pixels) using the software mentioned above in order to reduce noise, and then the observation increase is performed. was subjected to monochrome imaging processing and then binarization processing. In the binarization process, images with shading less than a predetermined threshold were cut off. The images were processed by assigning 1 to images with shading greater than or equal to the threshold value and 0 to images having gradation less than the threshold value. Binarization was performed using Otsu's method (discriminant analysis method).
Next, the filler area (μm ² ) in a region of 37.8 μm in width×18.9 μm in height in the binarized observed image was calculated.
The above processing was performed on six locations (see FIG. 2) in the binarized observed image. In this way, the filler area of each region was calculated. Using the obtained six filler area values, the standard deviation thereof (standard deviation of area (μm ² )) was calculated.
In addition to the standard deviation of the area (μm ² ), the standard deviation of the average value of the number of pixels mentioned above was also calculated.

(Evaluation of requirement 2)
Using the resin compositions of Examples 3, 10, 12, and Comparative Example 5, evaluation of Requirement 2 was performed according to the procedure shown below.
For the evaluation of Requirement 2, first, a binarized observation image was obtained in the same manner as above (evaluation of Requirement 1).
Next, the number of fillers in an area of 37.8 μm in width×18.9 μm in height in the binarized observed image was calculated. Through the above processing, the number of fillers in each of the six regions (see FIG. 2) in the binarized observed image was calculated. Using the values of the numbers of the six fillers obtained, the standard deviation (standard deviation of numbers (pieces)) was calculated.

In Table 4, "pressure between rolls (MPa)" represents the pressure between rolls (MPa) during roll milling.
In Table 4, "standard deviation of area (μm ² )" is the standard deviation of filler area calculated in the above (evaluation of requirement 1).
In Table 4, "standard deviation of area (number of pixels)" is the standard deviation of the average value of the number of pixels described above.
In Table 4, "standard deviation of number (pieces)" is the standard deviation of the number of fillers calculated in the above (evaluation of requirement 2).

As shown in Table 4 above, the resin compositions of Examples 3, 10, and 12 satisfy Requirements 1 and 2. It was confirmed that these compositions were excellent in the uniformity of the resin composition. It is considered that the desired effects were obtained by using a resin composition exhibiting such characteristics.

10 Test piece 12 Crack 20 Binarized observation image

Claims (13)

1. (A) epoxy resin,
   (B) a curing agent;
   (C) A resin composition comprising a filler,
   A resin composition in which a cured product of the resin composition has a fatigue crack propagation lower limit stress intensity factor range ΔK _th of 0.55 MPa·m ^0.5 or more.
2. The glass transition temperature (Tg) of the cured product of the resin composition is 100°C or higher,
   The resin composition according to claim 1.
3. The (A) epoxy resin includes a liquid epoxy resin,
   The resin composition according to claim 1 or 2.
4. The epoxy resin (A) contains at least one selected from the group consisting of bisphenol F-type epoxy resin, bisphenol A-type epoxy resin, aminophenol-type epoxy resin, naphthalene-type epoxy resin, and cyclohexane-type epoxy resin,
   The resin composition according to any one of claims 1 to 3.
5. The content of the filler (C) is 40 to 80 parts by mass based on 100 parts by mass of the total mass of all components of the resin composition.
   The resin composition according to any one of claims 1 to 4.
6. The filler (C) has an average particle size of 0.1 to 20.0 μm,
   The resin composition according to any one of claims 1 to 5.
7. The filler (C) is surface-treated with a silane coupling agent,
   The resin composition according to any one of claims 1 to 6.
8. Further (D) containing core shell rubber,
   The resin composition according to any one of claims 1 to 7.
9. The cured product of the resin composition satisfies the following requirements 1,
   The resin composition according to any one of claims 1 to 8.
   Requirement 1: Observe the cross section of the cured product of the resin composition with a scanning electron microscope at a magnification of 1000 times, and the average area (μm ² ) of the filler in a region of 37.8 μm in width x 18.9 μm in length. When ^the operation for calculating .
10. The cured product of the resin composition satisfies the following requirement 2,
    The resin composition according to any one of claims 1 to 9.
    Requirement 2: Observe the cross section of the cured product of the resin composition with a scanning electron microscope at a magnification of 1000 times, and calculate the number of fillers in an area of 37.8 μm in width x 18.9 μm in height. When the test is carried out at six randomly selected locations, the standard deviation of the number of six fillers obtained is 80 or less.
11. comprising a substrate, a semiconductor element disposed on the substrate, and a cured product of the resin composition according to any one of claims 1 to 10, which seals the semiconductor element.
    Semiconductor equipment.
12. Filling a gap between a substrate and a semiconductor element arranged on the substrate with the resin composition according to any one of claims 1 to 10, and curing the resin composition. A method for manufacturing a semiconductor device, comprising:
13. The method includes producing a resin composition by mixing the (A) epoxy resin, the (B) curing agent, and the (C) filler using a roll mill,
    The pressure between the rolls of the roll mill is 3.0 MPa or more,
    A method for producing a resin composition according to any one of claims 1 to 10.

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