WO2025204847A1 - Resin composition, adhesive agent, sealing material, cured product, semiconductor device, and electronic component - Google Patents

Abstract

The present invention addresses the problem of providing: a resin composition which is at least photocurable or curable at low temperatures (for example, at 100°C or less), and which gives a cured product that has excellent high-temperature high-humidity reliability; an adhesive agent or a sealing material which contains the resin composition; a cured product of the resin composition; a semiconductor device which comprises the cured product; and an electronic component.　The present invention provides: a resin composition which contains (A) an alicyclic epoxy compound, (B) an oxetane compound, (C) a filler, and (D) an acid generator that is a salt which is composed of an anion represented by formula (1) (wherein R₁, R₂, R₃, and R₄ each independently represent an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms, provided that at least one of R₁, R₂, R₃, and R₄ represents an aryl group having 6 to 14 carbon atoms) and a counter cation other than an iodonium cation; an adhesive agent or a sealing material which contains the resin composition; a cured product of the resin composition; a semiconductor device which comprises the cured product; and an electronic component.

Description

Resin compositions, adhesives, sealing materials, cured products, semiconductor devices and electronic components

The present invention relates to a resin composition, an adhesive or sealant containing the same, a cured product thereof, and a semiconductor device and electronic component containing the cured product.

Currently, adhesives, sealants, etc. containing curable resin compositions, particularly epoxy resin compositions, are often used in the assembly and installation of semiconductor devices and electronic components, such as semiconductor chips, in order to maintain reliability. While a variety of devices are being developed for IoT (Internet of Things) applications, including smartphones, the inability to manufacture them at high temperatures due to component issues and other factors has become an issue.

Development of photo-curable and/or low-temperature curable adhesives is underway. For example, Patent Document 1 discloses a UV/heat-curable adhesive composition that does not use an antimony compound as a thermal cationic polymerization initiator, is low in toxicity, can be cured at low temperatures of 120°C or less, and produces a cured product with excellent heat resistance. The composition contains specific amounts of an oxetane compound, an alicyclic epoxy compound, an aromatic glycidyl ether epoxy compound, a photo-cationic polymerization initiator, and a thermal cationic polymerization initiator containing a tetrakis(pentafluorophenyl)borate compound.

Japanese Patent Application Laid-Open No. 2021-147584

Depending on the conditions of use, semiconductor devices and electronic components are exposed to high-temperature, high-humidity environments. Therefore, the cured adhesives used in the manufacture of semiconductor devices and electronic components are required to have excellent reliability under high-temperature, high-humidity conditions. In particular, the glass transition temperature (Tg) of adhesives used in semiconductor devices and electronic components is the temperature at which physical properties that affect the reliability of the semiconductor device or electronic component, such as the linear expansion coefficient, elastic modulus, and adhesive strength, change significantly. Therefore, even after the cured adhesive has been left in a high-temperature, high-humidity environment for an extended period of time, it is required that the change in Tg between the initial Tg of the cured adhesive and that after being left in a high-temperature, high-humidity environment is small.

The cured product of the adhesive composition disclosed in Patent Document 1 was found to have a large change in Tg before and after a pressure cooker test (PCT), which evaluates resistance to high temperatures and humidity.

The present invention aims to provide a resin composition that can be cured at least by light or at low temperatures (e.g., 100°C or less) and that produces a cured product with excellent reliability at high temperatures and high humidity, an adhesive or sealant containing the same, a cured product thereof, and a semiconductor device or electronic component containing the cured product.

Specific means for solving the above problems are as follows.
The present invention encompasses the following curable resin composition, adhesive or sealant, cured product, and semiconductor device or electronic component.
[1] (A) an alicyclic epoxy compound,
(B) an oxetane compound,
(C) a filler, and (D) a compound represented by the following formula (1):

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms, provided that at least one of R ₁ , R ₂ , R ₃ and R ₄ represents an aryl group having 6 to 14 carbon atoms.)
and a counter cation other than an iodonium cation.
[2] The resin composition according to the above [1], wherein the acid generator (D) is a thermal acid generator (D1).
[3] The resin composition according to the above [1], wherein the (D) acid generator is (D2) a photoacid generator.
[4] The resin composition according to the above [1], wherein the acid generator (D) is a combination of a thermal acid generator (D1) and a photoacid generator (D2).
[5] The resin composition according to any one of the above [1] to [4], wherein the counter cation in the acid generator (D) is a sulfonium cation or an ammonium cation.
[6] The resin composition according to any one of the above [1] to [5], wherein the content of the acid generator (D) is 0.1 to 10 parts by weight per 100 parts by weight of the total amount of the resin composition.
[7] The resin composition according to any one of the above [1] to [6], further comprising (E) an acid generator other than the component (D).
[8] The resin composition according to the above [7], wherein the acid generator other than the component (D) (E) contains a sulfonium cation or an ammonium cation.
[9] The resin composition according to any one of the above [1] to [8], further comprising (F) an epoxy compound other than an alicyclic epoxy compound.
[10] The resin composition according to the above [9], wherein the (F) epoxy compound other than the alicyclic epoxy compound includes an epoxy compound having an epoxy equivalent of 90 to 1000 g/eq.
[11] The resin composition according to the above [9] or [10], wherein the content of the epoxy compound other than the (F) alicyclic epoxy compound is 50 to 200 parts by weight per 100 parts by weight of the (A) alicyclic epoxy compound.
[12] The resin composition according to any one of [1] to [11] above, wherein the content of all epoxy compounds contained in the resin composition is 100 to 1,300 parts by weight per 100 parts by weight of the (B) oxetane compound.
[13] The resin composition according to any one of the above [1] to [12], wherein the components (A) to (D) are contained in a single container.
[14] The resin composition according to any one of the above [1] to [12], wherein the components (A) to (D) are separated into two or more containers.
[15] An adhesive or sealant comprising the resin composition according to any one of [1] to [14] above.
[16] A cured product obtained by curing the resin composition according to any one of [1] to [14] above, or the adhesive or sealant according to [15] above.
[17] A semiconductor device or electronic component comprising the cured product according to [16] above.

According to aspects of the present invention, there are provided a resin composition that can be cured at least by light or at low temperatures (e.g., 100°C or less) and that produces a cured product with excellent reliability under high temperatures and high humidity, an adhesive or sealant containing the same, a cured product thereof, and a semiconductor device and electronic component containing the cured product.

In this specification, following the convention in the field of synthetic resins, the term "resin," which normally refers to a polymer (especially a synthetic polymer), may be used to refer to the components that make up a curable resin composition before curing, even if the component is not a polymer, such as a prepolymer compound before curing.

[Resin composition]
The resin composition according to one embodiment of the present invention comprises:
(A) an alicyclic epoxy compound,
(B) an oxetane compound,
(C) a filler, and (D) a compound of the following formula (1):

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms, provided that at least one of R ₁ , R ₂ , R ₃ and R ₄ represents an aryl group having 6 to 14 carbon atoms.)
and a counter cation other than an iodonium cation. According to this aspect, there is provided a resin composition that can be cured at least with light or at a low temperature (for example, 100°C or lower) and that gives a cured product that has excellent reliability under high temperature and high humidity conditions.

(A) Alicyclic Epoxy Compound The resin composition of this embodiment contains (A) an alicyclic epoxy compound (hereinafter also referred to as "component (A)"). One type of alicyclic epoxy compound is a compound having at least one alicyclic epoxy group in the molecule, i.e., a cycloalkene oxide structure. The cycloalkene oxide structure is a structure in which an alicyclic ring and an epoxy ring share a part of the ring structure, such as a cyclohexene oxide structure or a cyclopentene oxide structure obtained by epoxidizing a cyclohexene ring-containing compound or a cyclopentene ring-containing compound with an oxidizing agent. From the viewpoint of ensuring heat resistance, the alicyclic epoxy compound preferably has 2 to 6 alicyclic epoxy groups, and even more preferably has 2 alicyclic epoxy groups. The number of carbon atoms in the alicyclic ring is not particularly limited. The alicyclic ring of the cycloalkene oxide structure is, for example, preferably a 5- to 8-membered ring, more preferably a 5- or 6-membered ring, and even more preferably a 6-membered ring.
In this specification, the alicyclic epoxy compound may have an epoxy group other than an alicyclic epoxy group. In addition, a compound having an aromatic ring also falls under the category of the alicyclic epoxy compound as long as it has an alicyclic epoxy group.

Examples of the above alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (such as Celloxide (registered trademark) 2021P manufactured by Daicel Corporation), 3,4-epoxy-1-methylcyclohexyl-3,4-epoxy-1-methylhexanecarboxylate, 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-3-methylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexanecarboxylate, 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, 3,4-epoxy-6-methylcyclohexanecarboxylate, methylenebis(3,4-epoxycyclohexane), propane-2,2-diyl-bis(3,4-epoxycyclohexane), 2,2-bis(3 ,4-epoxycyclohexyl)propane, dicyclopentadiene diepoxide, ethylene bis(3,4-epoxycyclohexanecarboxylate), limonene dioxide (1,2:8,9-diepoxylimonene), (3,3',4,4'-diepoxy)bicyclohexyl (Celloxide (registered trademark) 8010 manufactured by Daicel Corporation, etc.), dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1-epoxyethyl-3,4-ene Examples of epoxycyclohexane include, but are not limited to, 1,2-epoxy-2-epoxyethylcyclohexane, 1,2-epoxy-4-vinylcyclohexane, α-pinene oxide, 2,2-bis(3,4-epoxycyclohexyl)propane, 1,2-bis(3,4-epoxycyclohexyl)ethane, 1,2-epoxy-1,2-bis(3,4-epoxycyclohexyl-1-yl)ethane, and bis(3,4-epoxycyclohexylmethyl)ether.

In this specification, alicyclic epoxy compounds include not only compounds having the above-mentioned cycloalkene oxide structure, but also compounds containing an epoxy group other than an alicyclic epoxy group and an aliphatic ring, and compounds having an epoxy group in which oxygen atoms are bonded to two carbon atoms in an aliphatic chain. Examples of such alicyclic epoxy compounds include, but are not limited to, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (such as EHPE3150 manufactured by Daicel Corporation), epoxidized polybutadiene (such as EPOLEAD PB manufactured by Daicel Corporation), and compounds in which some or all of the double bonds of a styrene-butadiene copolymer have been epoxidized (such as EPOFRIEND manufactured by Daicel Corporation).

The epoxy equivalent of the alicyclic epoxy compound is preferably 90 to 1000 g/eq, more preferably 100 to 800 g/eq, even more preferably 100 to 500 g/eq, and particularly preferably 110 to 300 g/eq.

A single alicyclic epoxy compound may be used, or two or more may be used in combination.

In this embodiment, the content of the (A) alicyclic epoxy compound in the resin composition is preferably 1 to 70% by weight, more preferably 5 to 60% by weight, even more preferably 10 to 50% by weight, and particularly preferably 10 to 40% by weight, relative to the total weight of the resin composition. Furthermore, the content of the (A) alicyclic epoxy compound in the resin composition is preferably 10 to 1,000 parts by weight, more preferably 30 to 800 parts by weight, and even more preferably 40 to 600 parts by weight, relative to 100 parts by weight of the (B) oxetane compound described below.

(B) Oxetane Compound The resin composition of this embodiment contains (B) an oxetane compound (hereinafter also referred to as "component (B)"). The oxetane compound is a compound having at least one oxetane ring (e.g., a 3-oxetanyl group) in the molecule. Although the polymerization initiation reaction of an oxetane compound is slower than that of an alicyclic epoxy compound, it polymerizes rapidly once the polymerization initiation species reaches a certain concentration or higher, thereby contributing to the curing reaction of the resin composition at low temperatures in a short time. Furthermore, by including an oxetane compound in the resin composition, the change in Tg of the cured product is reduced even after the cured product is stored in a high-temperature, high-humidity environment for a long period of time. In one embodiment, the oxetane compound preferably has 1 to 6 oxetane rings in the molecule, and more preferably has 1 to 2 oxetane rings in the molecule.

Examples of oxetane compounds include, but are not limited to, bis[1-ethyl(3-oxetanyl)]methyl ether (also known as (3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane)), xylylene bisoxetane, 4,4'-bis[3-ethyl-(3-oxetanyl)methoxymethyl]biphenyl, 1,4-bis(3-ethyl-3-oxetanylmethoxy)methylbenzene, (bis[(3-ethyl-3-oxetanyl)methyl]isophthalate), 3-ethyl-3-hydroxymethyloxetane, 2-ethylhexyloxetane, (3-ethyloxetan-3-yl)methyl methacrylate, 3-ethyl-3-[(2-ethylhexyloxy)methyl]oxetane, 3-ethyl-3-(4-hydroxybutyl)oxymethyloxetane, and 3-ethyl-3-phenoxymethyloxetane. Other examples of oxetane compounds include oxetanyl silsesquioxetane (such as OXT-191 manufactured by Toagosei Co., Ltd.), 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (such as OXT-221 manufactured by Toagosei Co., Ltd.), and phenol novolac oxetane (such as PHOX manufactured by Toagosei Co., Ltd.). Any of the oxetane compounds may be used alone, or two or more may be used in combination.

The oxetane equivalent of the oxetane compound is preferably 90 to 500 g/eq, and may be 100 to 300 g/eq.

The content of the oxetane compound (B) in the resin composition is preferably 1 to 50 wt %, more preferably 2 to 40 wt %, and even more preferably 3 to 30 wt %, relative to the total weight of the resin composition.
From the viewpoint of low-temperature curing property, the content of the (B) oxetane compound in the resin composition is preferably 1 to 100 parts by weight, more preferably 5 to 85 parts by weight, relative to 100 parts by weight of the total content of all epoxy compounds contained in the resin composition. The total epoxy compounds refers to the sum of the (A) alicyclic epoxy compound and the epoxy compounds other than the (F) alicyclic epoxy compound described below.

(C) Filler The resin composition of this embodiment contains (C) filler (hereinafter also referred to as "component (C)"). By containing a filler in the resin composition, the fluidity, injectability, coatability, adhesion, etc. of the resin composition can be improved. In particular, even when the resin composition is cured by heating at a low temperature of 100°C or less, a cured product with good adhesion to the adherend can be obtained. Fillers are broadly classified into inorganic fillers and organic fillers.

The inorganic filler is not particularly limited as long as it is made of granular material and has the effect of lowering the linear expansion coefficient when added. Examples of inorganic materials that can be used include silica, talc, alumina, aluminum nitride, calcium carbonate, aluminum silicate, magnesium silicate, magnesium carbonate, barium sulfate, barium carbonate, lime sulfate, aluminum hydroxide, calcium silicate, potassium titanate, titanium oxide, zinc oxide, silicon carbide, silicon nitride, and boron nitride. One or more inorganic fillers may be used, or two or more may be used in combination. Silica filler is preferred as the inorganic filler, as it allows for a high loading. Amorphous silica is preferred as the silica. The surface of the inorganic filler may be treated with a coupling agent such as a silane coupling agent.

Examples of organic fillers include polytetrafluoroethylene (PTFE) fillers, silicone fillers, acrylic fillers, fillers with a urethane skeleton, fillers with a butadiene skeleton, and styrene fillers. The organic fillers may be surface-treated.

The shape of the filler is not particularly limited and may be spherical, flaky, needle-like, irregular, etc.

The average particle size of the filler is preferably 6.0 μm or less, more preferably 5.0 μm or less, and even more preferably 4.0 μm or less. In this specification, unless otherwise specified, the average particle size refers to the volume-based median diameter (d ₅₀ ) measured by laser diffraction in accordance with ISO-13320 (2009). By setting the average particle size of the filler to the upper limit or less, sedimentation of the filler can be suppressed, and the formation of coarse particles can be suppressed, thereby preventing wear on the jet dispenser nozzle and scattering of the resin composition ejected from the jet dispenser nozzle outside the desired area. The lower limit of the average particle size of the filler is not particularly limited, but from the viewpoint of the viscosity of the resin composition, it is preferably 0.005 μm or more, and more preferably 0.01 μm or more. In some embodiments of this aspect, the average particle size of the filler is preferably 0.01 μm to 5.0 μm, more preferably 0.1 μm to 3.0 μm. Fillers with different average particle sizes may be used in combination. For example, a filler having an average particle size of 0.005 μm or more and less than 0.1 μm and a filler having an average particle size of 0.1 μm to 6.0 μm may be used in combination.

You can use one type of filler or two or more types in combination.

The filler content in the resin composition of this embodiment is preferably 15 to 50% by weight, more preferably 20 to 45% by weight, and even more preferably 30 to 45% by weight, relative to the total weight of the resin composition.

(D) Acid Generator The resin composition of this embodiment contains (D) an acid generator represented by the following formula (1):

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms, provided that at least one of R ₁ , R ₂ , R ₃ and R ₄ represents an aryl group having 6 to 14 carbon atoms.)
and a counter cation other than an iodonium cation (hereinafter also referred to as "(D) acid generator,""(D) gallate acid generator," or "component (D)"). The acid generator generates an acid as an active species in response to light or heat, thereby promoting polymerization of the cationically polymerizable compound. By including an acid generator that is a salt formed from an anion represented by formula (1) (hereinafter also referred to as "gallate anion") and a counter cation other than an iodonium cation, the resin composition can be cured at least with light or at low temperatures (for example, 100°C or less), and can give a cured product that exhibits excellent reliability under high temperatures and high humidity conditions.

By including an acid generator having the specific structure, the resin composition can be cured at least by light or at low temperatures (e.g., 100°C or below). Furthermore, the inventors have discovered that by including an acid generator having this specific structure in a resin composition, the change in Tg of the cured product is small even after the cured product is left in a high-temperature, high-humidity environment for an extended period of time. Specifically, the change is small after a pressure cooker test (PCT) under conditions of 2 atm, 121°C, 100% RH, and 20 hours. The reasons for this are thought to be, but are not limited to, the following: The cation portion of the acid generator is decomposed by reaction, while the anion portion remains in the cured product of the composition. When the cured product is left in a high-temperature, high-humidity environment for an extended period of time, moisture that penetrates the cured product generates acid. The generated acid migrates through moisture, a polar solvent, and can sever crosslinks in the cured product. The gallate anion in this acid generator has a large ionic radius and molecular weight, which presumably prevents it from migrating within the cured product, making it less likely to undergo a crosslink-severing reaction. Furthermore, because the counter cation in the acid generator of this embodiment is other than an iodonium cation, when a cured product of the composition is placed in a high-temperature, high-humidity environment for a long period of time, iodic acid resulting from the iodonium cation is not generated, and a crosslink cleavage reaction due to iodic acid does not occur.

In one embodiment, the (D) acid generator is (D1) a thermal acid generator.
In one embodiment, the (D) acid generator is (D2) a photoacid generator.
In one embodiment, the acid generator (D) is a combination of a thermal acid generator (D1) and a photoacid generator (D2).

In formula (1), R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms, but at least one of R ₁ , R ₂ , R ₃ and R ₄ represents an aryl group having 6 to 14 carbon atoms. That is, R ₁ , R ₂ , R ₃ and R ₄ in formula (1) are any of the following combinations:
(i) A combination in which one of R ₁ , R ₂ , R ₃ and R ₄ is an aryl group and the remaining three are alkyl groups.
(ii) A combination in which two of R ₁ , R ₂ , R ₃ and R ₄ are aryl groups and the remaining two are alkyl groups.
(iii) A combination in which three of R ₁ , R ₂ , R ₃ and R ₄ are aryl groups and the remaining one is an alkyl group.
(iv) A combination in which all of R ₁ , R ₂ , R ₃ and R ₄ are aryl groups.
Of the above combinations, the anion (iii) or (iv) is preferred, and the anion (iv) is more preferred.

R ₁ , R ₂ , R ₃ and R in formula (1) The alkyl group having 1 to 18 carbon atoms represented by ₄ may be any of a linear, branched, or cyclic alkyl group, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a t-pentyl group, a sec-pentyl group, an n-hexyl group, an isohexyl group, an n-heptyl group, a sec-heptyl group, an n-octyl group, an n-nonyl group, a sec-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, a cyclopentyl group, and a cyclohexyl group.
The alkyl groups having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) may have a substituent. The term "substituted alkyl group" used here refers to an alkyl group in which a hydrogen atom in the structure of the alkyl group is substituted with a substituent, and the position and number of the substituent are not particularly limited. Note that when the substituent has a carbon atom, the number of carbon atoms in the alkyl group represented by R ₁ , R ₂ , R ₃ and R ₄ does not include the number of carbon atoms in the substituent. Specifically, for example, an ethyl group having a phenyl group as a substituent is an alkyl group having 2 carbon atoms.

The substituents that the alkyl groups having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) may have are not particularly limited (excluding alkyl groups). Examples of such substituents include alkoxy groups, aromatic groups, heterocyclic groups, halogen atoms, hydroxyl groups, mercapto groups, nitro groups, alkyl-substituted amino groups, aryl-substituted amino groups, unsubstituted amino groups (NH ₂ groups), cyano groups, and isocyano groups.

The alkoxy group which may be substituted by the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) is a substituent in which an oxygen atom and an alkyl group are bonded. Examples of the alkyl group which this alkoxy group has include the same alkyl groups as those described in the section on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1).
The aromatic group that may be substituted on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) is not particularly limited as long as it is a residue in which one hydrogen atom has been removed from the aromatic ring of an aromatic compound. Examples of such aromatic groups include a phenyl group, a biphenyl group, a terphenyl group, a quaterphenyl group, a tolyl group, an indenyl group, a naphthyl group, an anthryl group, a fluorenyl group, a pyrenyl group, a phenanthenyl group and a mestyl group.
The heterocyclic group which may be substituted by the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) is not particularly limited as long as it is a residue obtained by removing one hydrogen atom from the heterocyclic ring of a heterocyclic compound. Examples of such heterocyclic groups include a furanyl group, a thienyl group, a thienothienyl group, a pyrrolyl group, an imidazolyl group, an N-methylimidazolyl group, a thiazolyl group, an oxazolyl group, a pyridyl group, a pyrazyl group, a pyrimidyl group, a quinolyl group, an indolyl group, a benzopyrazyl group, a benzopyrimidyl group, a benzothienyl group, a naphthothienyl group, a benzofuranyl group, a benzothiazolyl group, a pyridinothiazolyl group, a benzimidazolyl group, a pyridinoimidazolyl group, an N-methylbenzimidazolyl group, a pyridino-N-methylimidazolyl group, a benzoxazolyl group, a pyridinooxazolyl group, a benzothiadiazolyl group, a pyridinothiadiazolyl group, a benzoxadiazolyl group, a pyridinooxadiazolyl group, a carbazolyl group, a phenoxazinyl group, and a phenothiazinyl group.
Examples of halogen atoms that may be substituted on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The alkyl-substituted amino group which the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) may have as a substituent may be either a monoalkyl-substituted amino group or a dialkyl-substituted amino group. Examples of the alkyl group in these alkyl-substituted amino groups include the same alkyl groups as those described in the section on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1).
The aryl-substituted amino group which may be substituted on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) may be either a monoaryl-substituted amino group or a diaryl-substituted amino group. Examples of the aryl group in these aryl-substituted amino groups include the same aromatic groups as those which may be substituted on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1).

Specific examples of the aryl group having 6 to 14 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) include the same aromatic groups as the substituents that may be possessed by the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1).

The aryl group having 6 to 14 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) may have a substituent. The term "substituted aryl group" used herein refers to an aryl group in which a hydrogen atom in the structure of the aryl group is substituted with a substituent, and the position and number of the substituent are not particularly limited. Note that when the substituent has a carbon atom, the number of carbon atoms in the aryl group represented by R ₁ , R ₂ , R ₃ and R ₄ does not include the number of carbon atoms in the substituent. Specifically, for example, a phenyl group having an ethyl group as a substituent is an aryl group having 6 carbon atoms.

There is no particular limitation on the substituent that the aryl group having 6 to 14 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) may have. Examples of such substituents include an alkyl group, an alkoxy group, an aromatic group, a heterocyclic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group, an alkyl-substituted amino group, an aryl-substituted amino group, an unsubstituted amino group (NH ₂ group), a cyano group, an isocyano group, and the like.

Examples of the alkyl group that may be substituted on the aryl group having 6 to 14 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1) include the same alkyl groups as those described in the section on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1).
Specific examples of the alkoxy group, aromatic group, heterocyclic group, halogen atom, alkyl-substituted amino group and aryl-substituted amino group which the aryl group having 6 to 14 carbon atoms represented by R _{1 ,} R ₂ , R ₃ and R ₄ in formula (1) may have as a substituent include the same as the alkoxy group, aromatic group, _heterocyclic group, halogen atom, alkyl-substituted amino group and aryl-substituted amino group which the alkyl group having 1 to 18 carbon atoms represented by R 1, R ₂ , R 3 and R ₄ in formula (1) may have as a substituent.

In formula (1), R ₁ , R ₂ , R ₃ and R ₄ are preferably a phenyl group having a perfluoroalkyl group as a substituent or a phenyl group having a fluorine atom as a substituent, and more preferably a pentafluorophenyl group or a bis(trifluoromethyl)phenyl group.

Specific examples of the gallate anion of formula (1) include, but are not limited to, the following:

The counter cation other than the iodonium cation that forms a salt with the gallate anion represented by (1) is not particularly limited as long as it is a monovalent cation other than the iodonium cation, and examples include a sulfonium cation, an ammonium cation, and a phosphonium cation. In one embodiment, the counter cation is preferably a sulfonium cation or an ammonium cation, and more preferably a sulfonium cation.

When the acid generator (D) is a thermal acid generator (D1), the counter cation other than the iodonium cation that forms a salt with the gallate anion represented by formula (1) is, from the viewpoint of efficiently generating an acid by heat, a cation represented by the following formula (2):

(In the formula,
_R5 and _R6 are alkyl groups or aralkyl groups;
_R7 represents hydrogen, an alkyl group, a hydroxy group, a carboxy group, an alkoxy group, an aryloxy group, an alkylcarbonyl group, an arylcarbonyl group, an aralkylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an aralkyloxycarbonyl group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an aralkylcarbonyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an aralkyloxycarbonyloxy group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, a heterocyclic hydrocarbon group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy(poly)alkyleneoxy group, an optionally substituted silyl group and an amino group, a cyano group, a nitro group, or a halogen atom;
n represents the number of _R7 , and n represents an integer of 0 to 5;
When n is 2 to 5, R ₇ may be the same or different, and two or more R ₇ may be bonded to each other directly or via —O—, —S—, —SO—, —SO ₂ —, —NH—, —CO—, —COO—, —CONH—, an alkylene group, or a phenylene group to form a ring structure containing the element S.
Preferred is a sulfonium cation represented by the following formula:

In formula (2), examples of the alkyl group represented by R ₅ , R ₆ and R ₇ include the same alkyl groups as those described in the section on the alkyl group having 1 to 18 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ in formula (1).

In formula (2), the aralkyl group represented by _R5 and _R6 includes a lower alkyl group substituted with an aryl group having 6 to 10 carbon atoms. Specific examples of the aralkyl group include a benzyl group, a 2-methylbenzyl group, a 1-naphthylmethyl group, and a 2-naphthylmethyl group.

In formula (2), the alkoxy group represented by _R7 includes a linear alkoxy group having 1 to 18 carbon atoms, or a branched alkoxy group having 3 to 18 carbon atoms. Specific examples of the alkoxy group include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, decyloxy, dodecyloxy, and octadecyloxy.

In formula (2), the aryloxy group represented by R ₇ includes aryloxy groups having 6 to 10 carbon atoms, and specific examples thereof include phenoxy and naphthyloxy.

In formula (2), the alkylcarbonyl group represented by _R7 includes a linear alkylcarbonyl group having 2 to 18 carbon atoms and a branched alkylcarbonyl group having 4 to 18 carbon atoms. Specific examples of the alkylcarbonyl group include acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, octanoyl, decanoyl, dodecanoyl, and octadecanoyl.

In formula (2), the arylcarbonyl group represented by R ₇ includes arylcarbonyl groups having 7 to 11 carbon atoms, and specific examples thereof include benzoyl and naphthoyl.

In formula (2), the aralkylcarbonyl group represented by _R7 includes a lower alkylcarbonyl group substituted with an aryl group having 6 to 10 carbon atoms, and specific examples thereof include benzylcarbonyl, 2-methylbenzylcarbonyl, 1-naphthylmethylcarbonyl, and 2-naphthylmethylcarbonyl.

In formula (2), the alkoxycarbonyl group represented by _R7 includes a linear alkoxycarbonyl group having 2 to 19 carbon atoms and a branched alkoxycarbonyl group having 4 to 19 carbon atoms. Specific examples of the alkoxycarbonyl group include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, octyloxycarbonyl, tetradecyloxycarbonyl, and octadecyloxycarbonyl.

In formula (2), the aryloxycarbonyl group represented by R ₇ includes aryloxycarbonyl groups having 7 to 11 carbon atoms, and specific examples thereof include phenoxycarbonyl and naphthoxycarbonyl.

In formula (2), the aralkyloxycarbonyl group represented by _R7 includes a lower alkoxycarbonyl group substituted with an aryl group having 6 to 10 carbon atoms, such as benzyloxycarbonyl, 2-methylbenzyloxycarbonyl, 1-naphthylmethyloxycarbonyl, and 2-naphthylmethyloxycarbonyl.

In formula (2), the alkylcarbonyloxy group represented by _R7 includes a straight-chain or branched-chain alkylcarbonyloxy group having 2 to 19 carbon atoms. Specific examples thereof include acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, and octadecylcarbonyloxy.

In formula (2), the arylcarbonyloxy group represented by R ₇ includes an arylcarbonyloxy group having 7 to 11 carbon atoms, such as benzoyloxy and naphthoyloxy.

In formula (2), the aralkylcarbonyloxy group represented by _R7 includes a lower alkylcarbonyl group substituted with an aryl group having 6 to 10 carbon atoms, such as benzylcarbonyloxy, 2-methylbenzylcarbonyloxy, 1-naphthylmethylcarbonyloxy, and 2-naphthylmethylcarbonyloxy.

In formula (2), the alkoxycarbonyloxy group represented by _R7 includes a straight-chain or branched-chain alkoxycarbonyl group having 2 to 18 or 2 to 19 carbon atoms. Specific examples thereof include methoxycarbonyloxy, ethoxycarbonyloxy, propoxycarbonyloxy, isopropoxycarbonyloxy, butoxycarbonyloxy, isobutoxycarbonyloxy, sec-butoxycarbonyloxy, tert-butoxycarbonyloxy, octyloxycarbonyloxy, tetradecyloxycarbonyloxy, and octadecyloxycarbonyloxy.

In formula (2), the aryloxycarbonyloxy group represented by _R7 includes an aryloxycarbonyloxy group having 7 to 11 carbon atoms, such as phenoxycarbonyloxy and naphthoxycarbonyloxy.

In formula (2), the aralkyloxycarbonyloxy group represented by _R7 includes a lower alkoxycarbonyloxy group substituted with an aryl group having 6 to 10 carbon atoms, such as benzyloxycarbonyloxy, 2-methylbenzyloxycarbonyloxy, 1-naphthylmethyloxycarbonyloxy, and 2-naphthylmethyloxycarbonyloxy.

In formula (2), the arylthiocarbonyl group represented by R ₇ includes arylthiocarbonyl groups having 7 to 11 carbon atoms, and specific examples thereof include phenylthiocarbonyl and naphthoxythiocarbonyl.

In formula (2), the acyloxy group represented by _R7 includes a linear acyloxy group having 2 to 19 carbon atoms and a branched acyloxy group having 4 to 19 carbon atoms. Specific examples of the acyloxy group include acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, and octadecylcarbonyloxy.

In formula (2), examples of the arylthio group represented by _R7 include arylthio groups having 6 to 20 carbon atoms. Specific examples of the arylthio group include phenylthio, 2-methylphenylthio, 3-methylphenylthio, 4-methylphenylthio, 2-chlorophenylthio, 3-chlorophenylthio, 4-chlorophenylthio, 2-bromophenylthio, 3-bromophenylthio, 4-bromophenylthio, 2-fluorophenylthio, 3-fluorophenylthio, 4-fluorophenylthio, 2-hydroxyphenylthio, 4-hydroxyphenylthio, 2-methoxyphenylthio, 4-methoxyphenylthio, 1-naphthylthio, 2-naphthylthio, 4-[4-(phenylthio)benzoyl]phenylthio, and 4-[4-(phenylthio)phenoxy]phenylthio. nylthio, 4-[4-(phenylthio)phenyl]phenylthio, 4-(phenylthio)phenylthio, 4-benzoylphenylthio, 4-benzoyl-2-chlorophenylthio, 4-benzoyl-3-chlorophenylthio, 4-benzoyl-3-methylthiophenylthio, 4-benzoyl-2-methylthiophenylthio, 4-(4-methylthiobenzoyl)phenylthio, 4-(2-methylthiobenzoyl)phenylthio, 4-(p-methylbenzoyl)phenylthio, 4-(p-ethylbenzoyl)phenylthio, 4-(p-isopropylbenzoyl)phenylthio, and 4-(p-tert-butylbenzoyl)phenylthio.

In formula (2), the alkylthio group represented by R ₇ includes a linear alkylthio group having 1 to 18 carbon atoms and a branched alkylthio group having 3 to 18 carbon atoms. Specific examples of the alkylthio group include methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, sec-butylthio, tert-butylthio, pentylthio, isopentylthio, neopentylthio, tert-pentylthio, octylthio, decylthio, dodecylthio, and isooctadecylthio.

In formula (2), the aryl group represented by R ₇ includes aryl groups having 6 to 10 carbon atoms, and specific examples thereof include phenyl, tolyl, dimethylphenyl, and naphthyl.

In formula (2), examples of the heterocyclic hydrocarbon group represented by _R7 include heterocyclic hydrocarbon groups having 4 to 20 carbon atoms. Specific examples thereof include thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, quinolyl, isoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thianthrenyl, phenoxazinyl, phenoxathiinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, thioxanthonyl, and dibenzofuranyl.

In formula (2), the alkylsulfinyl group represented by R ₇ includes a linear alkylsulfinyl group having 1 to 18 carbon atoms and a branched sulfinyl group having 3 to 18 carbon atoms. Specific examples thereof include methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, butylsulfinyl, isobutylsulfinyl, sec-butylsulfinyl, tert-butylsulfinyl, pentylsulfinyl, isopentylsulfinyl, neopentylsulfinyl, tert-pentylsulfinyl, octylsulfinyl, and isooctadecylsulfinyl.

In formula (2), the arylsulfinyl group represented by R ₇ includes an arylsulfinyl group having 6 to 10 carbon atoms, such as phenylsulfinyl, tolylsulfinyl, and naphthylsulfinyl.

In formula (2), examples of the alkylsulfonyl group represented by _R7 include linear alkylsulfonyl groups having 1 to 18 carbon atoms and branched alkylsulfonyl groups having 3 to 18 carbon atoms. Specific examples thereof include methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, tert-pentylsulfonyl, octylsulfonyl, and octadecylsulfonyl.

In formula (2), the arylsulfonyl group represented by _R7 includes arylsulfonyl groups having 6 to 10 carbon atoms. Specific examples thereof include phenylsulfonyl, tolylsulfonyl (tosyl group), and naphthylsulfonyl.

In formula (2), the hydroxy(poly)alkyleneoxy group represented by R ₇ includes the following formula (3):
HO(-AO)q- (3)
(In the formula, AO represents an ethyleneoxy group and/or a propyleneoxy group, and q represents an integer of 1 to 5.)
Examples thereof include a hydroxy(poly)alkyleneoxy group represented by the following formula:

In formula (2), the optionally substituted silyl group represented by _R7 includes a substituted silyl group having 1 to 18 carbon atoms. Specific examples thereof include silyl, methylsilyl, dimethylsilyl, trimethylsilyl, phenylsilyl, methylphenylsilyl, dimethylphenylsilyl, diphenylsilyl, diphenylmethylsilyl, and triphenylsilyl.

In formula (2), examples of the amino group represented by R ₇ include an amino group (—NH ₂ ) and a substituted amino group having 1 to 15 carbon atoms. Specific examples of the substituted amino group include methylamino, dimethylamino, ethylamino, methylethylamino, diethylamino, n-propylamino, methyl-n-propylamino, ethyl-n-propylamino, n-propylamino, isopropylamino, isopropylmethylamino, isopropylethylamino, diisopropylamino, phenylamino, diphenylamino, methylphenylamino, ethylphenylamino, n-propylphenylamino, and isopropylphenylamino.

In formula (2), examples of the halogen atom represented by R ₇ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

In formula (2), when n is 2 to 5, R _7s are mutually independent and may be the same or different.

_R7 is preferably a hydroxy group, an alkoxy group, an alkylcarbonyloxy group, or an aralkyloxycarbonyloxy group, and more preferably a hydroxy group, a methoxy group, an acetyloxy group, or a benzyloxycarbonyloxy group.

n represents the number of _R7 , and _R7 is an integer of 0 to 5, preferably 0 to 3, more preferably 0 to 2, and even more preferably 0 or 1. When _R7 is within these preferred ranges, the thermal sensitivity of the sulfonium salt becomes even better.

Among the groups represented by formula (2), preferred specific examples are shown below. More preferred are:
A sulfonium cation in which, in formula (2), R ₅ is a methyl group, R ₆ is a naphthyl group, and R ₇ is a hydroxy group;
A sulfonium cation in which, in formula (2), R ₅ is a methyl group, R ₆ is a benzyl group, and R ₇ is a hydroxy group;
A sulfonium cation in which, in formula (2), R ₅ is a methyl group, R ₆ is a 4-nitrobenzyl group, and R ₇ is a hydroxy group; and a sulfonium cation in which, in formula (2), R ₅ and R ₆ are methyl groups, and R ₇ is an acetoxy group.

When the (D) acid generator is a (D2) photoacid generator, the counter cation other than the iodonium cation that forms a salt with the gallate anion represented by formula (1) can be, from the viewpoint of efficiently generating an acid with light, for example, triphenylsulfonium, tri-p-tolylsulfonium, tri-o-tolylsulfonium, tris(4-methoxyphenyl)sulfonium, 1-naphthyldiphenylsulfonium, 2-naphthyldiphenylsulfonium, tris(4-fluorophenyl)sulfonium, tri-1-naphthylsulfonium, tri-2-naphthylsulfonium, tris(4-hydroxyphenyl)sulfonium, 4-(phenylthio)phenyldiphenylsulfonium, 4-(p-tolylthio)phenyldi-p-tolylsulfonium, 4-(4-methoxyphenylthio)phenylbis(4- 4-(4-(2-hydroxyethoxy)phenyl)sulfonio}phenyl]sulfide, bis[4-(4-(2-hydroxyethoxy)phenyl]sulfonio}phenyl]sulfide, bis{4-[bis(4-fluorophenyl)sulfonio]phenyl}sulfide, bis{4-[bis(4-methylphenyl)sulfonio]phenyl}sulfide, bis{4-[bis(4-methylphenyl)sulfonio]phenyl}sulfide, bis{4-[bis(4-methylphenyl)sulfonio]phenyl}sulfide, 4-(4-benzoyl-2-chlorophenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoyl-2-chlorophenylthio)phenyldiphenylsulfonium, 4-(4-benzoylphenylthio)phenylbis(4-fluorophenyl)sulfonium, 4-(4-benzoylphenylthio)phenyldiphenylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldi-p-tolylsulfonium, 7-isopropyl-9-oxo-10-thia-9,10-dihydroanthracen-2-yldiphenylsulfonium, 2-[(di-p-tolyl)sulfonio]thioxanthone, 2-[(diphenyl)sulfonio]thioxanthone, 4-(9 Examples of triarylsulfonium compounds include 4-[4-(4-t-butylbenzoyl)phenylthio]phenyldi-p-tolylsulfonium, 4-[4-(4-t-butylbenzoyl)phenylthio]phenyldiphenylsulfonium, 4-[4-(benzoylphenylthio)]phenyldi-p-tolylsulfonium, 4-[4-(benzoylphenylthio)]phenyldiphenylsulfonium, 5-(4-methoxyphenyl)thiaanthrenenium, 5-phenylthiaanthrenenium, 5-tolylthiaanthrenenium, 5-(4-ethoxyphenyl)thiaanthrenenium, and 5-(2,4,6-trimethylphenyl)thiaanthrenenium.

Examples of ammonium cations include pyrrolidiniums such as N,N-dimethylpyrrolidinium, N-ethyl-N-methylpyrrolidinium, and N,N-diethylpyrrolidinium; imidazoliniums such as N,N'-dimethylimidazolinium, N,N'-diethylimidazolinium, N-ethyl-N'-methylimidazolinium, 1,3,4-trimethylimidazolinium, and 1,2,3,4-tetramethylimidazolinium; tetrahydropyrimidiniums such as N,N'-dimethyltetrahydropyrimidinium; and morpholiniums such as N,N'-dimethylmorpholinium. Examples include sulfolinium, piperidinium such as N,N'-diethylpiperidinium, pyridinium such as N-methylpyridinium, N-benzylpyridinium, and N-phenacylpyridinium, imidazolium such as N,N'-dimethylimidazolium, quinolium such as N-methylquinolium, N-benzylquinolium, and N-phenacylquinolium, isoquinolium such as N-methylisoquinolium, thiazonium such as benzylbenzothiazonium and phenacylbenzothiazonium, and acridium such as benzylacridium and phenacylacridium.

In this embodiment, the content of the acid generator (D) in the resin composition is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 8 parts by weight, and even more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total amount of the resin composition. The content of the acid generator (D) in the resin composition is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, and even more preferably 1 to 15 parts by weight, per 100 parts by weight of the total amount of the components (A) and (B). Furthermore, the content of the acid generator (D) in the resin composition is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 15 parts by weight, and even more preferably 1 to 10 parts by weight, per 100 parts by weight of the total amount of the components (A), (B), and the component (F) described below.

(E) Acid Generator Other Than Component (D) The resin composition of this embodiment may, if desired, contain an acid generator other than component (D) (E) (hereinafter also referred to as "component (E)") within a range that does not impair the effects of the present invention. Surprisingly, as long as the resin composition of this embodiment contains the acid generator of component (D), even if it contains an acid generator other than component (D) (E), the change in Tg of the cured product of the resin composition after being left in a high-temperature, high-humidity environment for a long period of time was kept small. (E) Examples of acid generators other than component (D) include various onium salts having a counter anion such as BF ₄ ⁻ , SbF ₆ − , AsF ₆ ⁻ , B(C ₆ F ₅ ) ₄ ⁻ , C(CF ₃ SO ₂ ) ₃ ^{− ,} [P(R ₈ ) _a F _{6-a ]} ⁻ , [C(R ₈ SO ₂ ) ₃ ] − , or [N(R 8 SO ₂ ) ₂ ] ⁻ (wherein R ₈ is each independently an alkyl group in which at least a portion of the hydrogen atoms is substituted with fluorine atoms, a is an integer of 0 to 5, and when a is an integer of 2 or greater, multiple R _8s may be the same or different), and a sulfonium cation, ammonium cation, phosphonium cation, iodonium cation, or the like as the cation moiety.

(E) Acid generators other than component (D) preferably contain a sulfonium cation or an ammonium cation as the cation moiety, and more preferably contain a sulfonium cation, in order to avoid impairing the excellent high-temperature, high-humidity reliability obtained by acid generator (D). (E) Acid generators other than component (D) may contain an iodonium cation as long as the effects of the present invention are not impaired, but it is preferable that they do not contain an iodonium cation.

In one embodiment, when the acid generator (D) is a thermal acid generator (D1), the acid generator other than the component (D) (E) is a photoacid generator.
In one embodiment, when the (D) acid generator is (D2) a photoacid generator, the (E) acid generator other than component (D) is a thermal acid generator.

The acid generator other than component (E) (D) can be a commercially available product. Examples of commercially available products include photoacid generators that are borate-based sulfonium salts (products of San-Apro Ltd.: CPI-110B, CPI-310B, CPI-410B, etc.), photoacid generators that are sulfonium salts with PF ₃ (C ₂ F ₅ ) ₃ (products of San-Apro Ltd.: CPI-210S, VC-1S, CPI-410S, etc.), thermal acid generators that are sulfonium salts with PF ₃ (C ₂ F ₅ ) ₃ (products of San-Apro Ltd.: TA-100, etc.), and thermal acid generators that are borate-based quaternary ammonium salts (products of King Industries, Inc.: CXC-1821, etc.), but are not limited to these. The acid generators other than component (E) (D) may be used alone or in combination of two or more.

The content of the acid generator (E) other than component (D) in the resin composition is preferably 0.5 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total of components (A), (B), and (F) described below.

(F) Epoxy Compounds Other Than Alicyclic Epoxy Compounds The resin composition of this embodiment may contain (F) an epoxy compound other than an alicyclic epoxy compound (hereinafter also referred to as "(F) other epoxy compound" or "component (F)"). Examples of epoxy compounds other than alicyclic epoxy compounds include monofunctional epoxy compounds having one epoxy group that is not an alicyclic epoxy group, and polyfunctional epoxy compounds having two or more epoxy groups that are not alicyclic epoxy groups. (F) Other epoxy compounds are broadly classified into epoxy compounds having an aromatic ring skeleton and aliphatic epoxy compounds.

Examples of epoxy compounds having an aromatic ring skeleton include polyfunctional epoxy resins such as:
Bisphenol A type epoxy resins (for example, EPICLON (registered trademark) 850, 850-S, EXA-850CRP, EXA-8067, etc., manufactured by DIC Corporation),
Polyalkylene oxide-modified bisphenol A type epoxy resins, for example, polypropylene oxide-modified bisphenol A type epoxy resins (for example, AER9000 manufactured by Asahi Kasei Corporation, EP-4000S, EP-4003S, EP-4005, and EP-4010S manufactured by ADEKA Corporation), polyethylene oxide-modified bisphenol A type epoxy resins (for example, Rikaresin BEO-60E manufactured by New Japan Chemical Co., Ltd.),
Bisphenol F type epoxy resin (for example, EPICLON (registered trademark) 830-S, EXA-830LVP, etc. manufactured by DIC Corporation),
- bisphenol AD type epoxy resin,
- bisphenol S type epoxy resin,
- naphthalene-type epoxy resins (for example, EPICLON (registered trademark), HP-4032D, HP-720H, etc., manufactured by DIC Corporation),
-phenol novolac epoxy resins (for example, EPICLON (registered trademark) N-740, N-770, etc. manufactured by DIC Corporation),
Cresol novolac epoxy resin (for example, EPICLON (registered trademark), N-660, N-670, N-655-EXP-S, etc., manufactured by DIC Corporation)
- polyfunctional epoxy compounds such as glycidyl ethers of tetra(hydrophenyl)alkanes and glycidyl ethers of tetrahydroxybenzophenone;
- epoxidized polyvinylphenol, and the like.
Examples of monofunctional epoxy compounds having an aromatic ring skeleton include, but are not limited to, p-tert-butylphenyl glycidyl ether (e.g., ADEKA GLYCIROL (registered trademark), ED-509E, ED-509S, etc., manufactured by ADEKA Corporation) and 2-phenylphenol glycidyl ether (e.g., OPP-G, etc., manufactured by SANKO CO., LTD.).

Aliphatic epoxy compounds are epoxy compounds that do not have either an aromatic ring skeleton or an alicyclic epoxy group. Examples include glycidyl ethers of aliphatic alcohols (including chain alcohols and alicyclic alcohols) or their polyalkylene oxide adducts, and hydrogenated bisphenol-type epoxy resins obtained by hydrogenating bisphenol-type epoxy resins such as bisphenol A-type epoxy resins and bisphenol F-type epoxy resins. Examples of aliphatic epoxy compounds include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether (e.g., Epolite 100MF manufactured by Kyoeisha Chemical Co., Ltd.), polyethylene glycol diglycidyl ether, and polybutylene glycol diglycidyl ether. (e.g., jER YX7400N manufactured by Mitsubishi Chemical Corporation), lauryl alcohol polyethylene glycol glycidyl ether (e.g., Denacol EX-171 manufactured by Nagase ChemteX Corporation), diglycidyl ether of alicyclic diol (e.g., ADEKA Resin EP-4088S and EP-4088L manufactured by ADEKA Corporation), diglycidyl ether of polyalkylene oxide adduct of alicyclic diol, and hydrogenated bisphenol A diglycidyl ether (e.g., jER YX8000 manufactured by Mitsubishi Chemical Corporation), but are not limited to these.

(F) The epoxy equivalent of the other epoxy compounds is preferably 90 to 1000 g/eq, more preferably 120 to 800 g/eq, and even more preferably 150 to 500 g/eq.

(F) Other epoxy compounds may be used alone or in combination of two or more.

The content of the epoxy compound (F) other than the alicyclic epoxy compound in the resin composition is preferably 5 to 50 wt %, more preferably 10 to 40 wt %, and even more preferably 15 to 35 wt %, relative to the total weight of the resin composition.
The content of the epoxy compound other than the (F) alicyclic epoxy compound in the resin composition is preferably 50 to 200 parts by weight, and more preferably 100 to 150 parts by weight, per 100 parts by weight of the (A) alicyclic epoxy compound.

In this embodiment, from the viewpoint of low-temperature curing properties, the content of all epoxy compounds contained in the resin composition is preferably 100 to 1,300 parts by weight, more preferably 110 to 1,200 parts by weight, and even more preferably 120 to 1,100 parts by weight, per 100 parts by weight of the (B) oxetane compound. "Total epoxy compounds" refers to the sum of (A) alicyclic epoxy compounds and (F) epoxy compounds other than alicyclic epoxy compounds.

(G) Coupling Agent The resin composition of this embodiment may contain (G) a coupling agent (hereinafter also referred to as "component (G)"), if desired, to the extent that the effects of the present invention are not impaired. The coupling agent has two or more different functional groups in the molecule, one of which is a functional group that chemically bonds with inorganic materials and the other is a functional group that chemically bonds with organic materials. By including a coupling agent in the resin composition, the adhesive strength of the resin composition to substrates and the like is improved.

Examples of coupling agents include, but are not limited to, silane coupling agents, aluminum coupling agents, and titanium coupling agents, depending on the type of functional group that chemically bonds with the inorganic material.

Examples of coupling agents include, but are not limited to, various types of coupling agents, such as epoxy, amino, vinyl, methacrylic, acrylic, and mercapto, depending on the type of functional group that chemically bonds with the organic material. Of these, epoxy-based coupling agents containing epoxy groups are preferred from the standpoint of moisture resistance reliability.

Any one of the coupling agents may be used, or two or more may be used in combination.

If a coupling agent is added, the amount of coupling agent added is preferably 0.01% to 10% by weight, and more preferably 0.1% to 5% by weight, of the total weight of the resin composition, from the perspective of improving adhesive strength.

(H) Pigment The resin composition of this embodiment may contain (H) pigment (hereinafter also referred to as "component (H)") to the extent that the effects of the present invention are not impaired.
Light-blocking properties may be required depending on the application of the cured product of the resin composition. In such cases, the resin composition of this embodiment may contain a pigment. Examples of pigments include inorganic pigments such as carbon black, graphite, iron oxide, titanium black, anthraquinone, cobalt oxide, copper oxide, manganese oxide, antimony oxide, nickel oxide, perylene, aniline, molybdenum sulfide, and bismuth sulfide, as well as organic pigments such as azo, cyanine, phthalocyanine, and quinacridone pigments. Examples of commercially available pigments include Titanium Black 13M, 13M-C, and 13MT manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd. The amount of pigment added can be determined appropriately depending on the application of the cured product of the resin composition.

Other Additives If desired, the resin composition of this embodiment may further contain other additives, such as organic peroxides, photosensitizers, conductive fillers, stabilizers, ion trapping agents, leveling agents, antioxidants, antifoaming agents, viscosity modifiers, flame retardants, colorants, plasticizers, solvents, etc. The type and amount of each additive are as per usual, provided that the purpose of this embodiment is not impaired.

In order to prevent a reduction in curing strength and adhesion and to prevent outgassing and bleeding, the resin composition of this embodiment is substantially free of liquid components such as water, solvents, ionic liquids, etc. (excluding liquid components (A), (B), (D), and (F)). For example, the content of liquid components is preferably 3% by weight or less, and more preferably 1% by weight or less, relative to the total weight of the resin composition. Examples of solvents include organic solvents commonly used in the field of curable compositions, such as hydrocarbons (benzene, toluene, xylene, cyclohexane, etc.), aprotic polar solvents (N,N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, etc.), nitriles (acetonitrile, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (ethyl acetate, butyl acetate, butyrolactone, propylene carbonate, etc.), ethers (cyclopentyl methyl ether, diethyl ether, tetrahydrofuran, dimethoxyethane, etc.), alcohols (methanol, ethanol, propanol, butanol, etc.), terpenes (turpentine, terpineol, isobornyl acetate, etc.), and halogenated solvents (dichloromethane, chloroform, etc.).

The method for producing the resin composition of this embodiment is not particularly limited. For example, the resin composition of this embodiment can be obtained by simultaneously or separately introducing components (A) to (D), and other optional components as needed, into an appropriate mixer, and mixing and stirring while melting by heating if necessary to form a homogeneous composition. The mixer is not particularly limited, but examples that can be used include a Raikai mixer, Henschel mixer, three-roll mill, ball mill, planetary mixer, and bead mill equipped with a stirrer and heater. Appropriate combinations of these devices may also be used.

Depending on the intended use, the resin composition of this embodiment can be a one-component resin composition contained in a single container, or a two-component (or multi-component) resin composition divided into two or more containers. When a two-component (or multi-component) resin composition is used, components (A) to (D) and other optional components as needed can be selected in the same way as for a one-component resin composition. Furthermore, when a two-component (or multi-component) resin composition is used, components (A) to (D) and other optional components as needed can be divided into two or multiple components in any manner without particular restrictions. When divided into two or multiple components in any manner, each component may contain one or more components selected from components (A) to (D) and other optional components as needed. Components (A) to (D) may be contained in a single component, or a component may contain only components (A) to (D) and/or other optional components as needed. For example, when separating into liquid A and liquid B, the separation may be as follows: liquid A: component (A), liquid B: component (B) and component (C) and component (D), or liquid A: component (A) and component (C), liquid B: component (B) and component (D), or liquid A: component (A) and component (D), or liquid B: component (B) and component (C), or liquid A: component (B), liquid B: component (A) and component (C) and component (D), or liquid A: component (A), component (B) and component (C), or liquid B: component (A), component (C) and component (D). When components (A) to (D) are contained in liquid A and other components are contained in liquid B, only liquid A, or a combination of liquid A and liquid B, can be considered the resin composition of this embodiment. On the other hand, when components (A) to (D) are contained in separate liquids, the respective liquids can be combined to form the resin composition of this embodiment. An example of a case in which components (A) to (D) are contained in separate liquids is a resin composition in which components (A) to (D) are separated into two or more containers, specifically a kit composed of multiple liquids containing any of components (A) to (D).

The resin composition obtained in this manner may be photocurable, thermocurable, or photo- and thermo-curable, depending on the type of acid generator contained in the resin composition. If the resin composition is photocurable, the photocuring of the resin composition is carried out, for example, by irradiating the resin composition with UV light. If the resin composition is thermocurable, it preferably cures within 5 hours, more preferably within 3 hours, and even more preferably within 1 hour at a temperature of 100°C. In one embodiment, for example, the resin composition of this aspect is thermally cured at a temperature of 70 to 100°C for 30 to 120 minutes. If the resin composition is photo- and thermocurable, it can be further cured with heat, for example, after preliminary curing with light (UV) or during light irradiation.

The resin composition of this embodiment can be used, for example, as an adhesive or sealant for fixing, joining, or protecting semiconductor devices or electronic components, or the components that make them up, or as a raw material for such adhesives or sealants.

The method for applying the resin composition is not particularly limited, and for example, it can be applied to the desired portion of a component such as a substrate by a known printing method, dispensing method, or coating method. Printing methods include, but are not limited to, inkjet printing, screen printing, lithographic printing, carton printing, metal printing, offset printing, gravure printing, and flexographic printing. Dispensing methods include, but are not limited to, methods using a jet dispenser or air dispenser. Coating methods include, but are not limited to, dip coating, spray coating, bar coater coating, gravure coating, reverse gravure coating, and spin coater coating.

[Adhesive or sealant]
Another embodiment of the present invention is an adhesive or sealant that includes the resin composition of the above-described embodiment. This adhesive or sealant enables good fixation, bonding, or protection of general-purpose plastics (e.g., PE, PS, PP, etc.), engineering plastics (e.g., LCP (liquid crystal polymer), polyamide, polycarbonate, polyphthalamide, polybutylene terephthalate, etc.), glass, ceramics, metals (e.g., copper, nickel, etc.), and organic substrates (e.g., FR4, etc.), and can be used to fix, bond, or protect components that make up semiconductor devices or electronic components. Examples of semiconductor devices include, but are not limited to, HDDs, semiconductor elements, sensor modules such as image sensor modules and time-of-flight sensor modules, other semiconductor modules, and integrated circuits.

Depending on the intended use, the adhesive or sealant of this embodiment can be a one-component adhesive or sealant contained in a single container, or a two-component (or multi-component) adhesive or sealant separated into two or more containers. When a two-component (or multi-component) adhesive or sealant is used, the components (A) to (D) and other optional components as needed can be selected in the same way as for a one-component adhesive or sealant. Furthermore, when a two-component (or multi-component) adhesive or sealant is used, the components (A) to (D) and other optional components as needed can be separated into two or multiple components in any manner without particular restrictions. When separated into two or multiple components in any manner, each component may contain one or more components selected from the components (A) to (D) and other optional components as needed. Components (A) to (D) may be contained in a single component, or a component may contain only the components (A) to (D) and/or other optional components as needed. For example, when the liquid is divided into liquid A and liquid B, the division may be liquid A: component (A), liquid B: component (B), component (C), and component (D), or liquid A: component (A) and component (C), liquid B: component (B) and component (D), or liquid A: component (A) and component (D), liquid B: component (B) and component (C), or liquid A: component (B), liquid B: component (A), component (C), and component (D), or liquid A: component (A), component (B), and component (C), or liquid B: component (A), component (C), and component (D). When components (A) to (D) are contained in liquid A and other components are contained in liquid B, liquid A alone, or a combination of liquid A and liquid B, can be considered the adhesive or sealant of this embodiment. On the other hand, when components (A) to (D) are contained in separate liquids, the respective liquids can be considered together to be the adhesive or sealant of this embodiment. Examples of cases in which components (A) to (D) are contained in separate liquids include adhesives or sealants in which components (A) to (D) are separated into two or more containers, and specifically kits composed of multiple liquids containing any of components (A) to (D).

[Cured product of resin composition, adhesive, or sealant]
Another embodiment of the present invention is a cured product obtained by curing the resin composition, adhesive, or sealant of the above-described embodiment. This cured product has excellent high-temperature, high-humidity reliability. That is, even after the cured product is placed in a high-temperature, high-humidity environment for a long period of time, specifically, the change in Tg of the cured product before and after a pressure cooker test (PCT) under conditions of 2 atm, 121°C, 100% RH, and 20 hours is small. In this embodiment, the change in Tg of the cured product before and after a PCT under conditions of 2 atm, 121°C, 100% RH, and 20 hours is preferably less than 10.3°C, more preferably 8°C or less, and even more preferably 6°C or less.

[Semiconductor devices, electronic components]
Another aspect of the present invention is a semiconductor device or electronic component that includes the cured product of the above-described aspect. Here, the term "semiconductor device" refers to any device that can function by utilizing semiconductor properties, including electronic components, semiconductor circuits, modules incorporating these, electronic devices, etc. Examples of semiconductor devices or electronic components include, but are not limited to, HDDs, semiconductor elements, sensor modules such as image sensor modules and time-of-flight (TOF) sensor modules, other semiconductor modules, and integrated circuits.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, parts and percentages are by weight unless otherwise specified.

[Production of resin composition]
Resin compositions of the Examples and Comparative Examples were prepared by mixing predetermined amounts of each component using a three-roll mill according to the formulations shown in Table 1. In Table 1, the amount of each component is expressed in parts by weight (unit: g). The components used in the Examples and Comparative Examples are as follows:

(A) Alicyclic epoxy compound (A-1): 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (product name: CELLOXIDE (registered trademark) 2021P, manufactured by Daicel Corporation, epoxy equivalent: 130 g/eq)
(B) Oxetane Compound (B-1): 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (product name: OXT-221, manufactured by Toagosei Co., Ltd., oxetane equivalent: 107 g/eq)
(C) Filler (C-1): Hydrophobic fumed silica (product name: CAB-O-SIL (registered trademark) TS720, manufactured by CABOT Corporation, average particle size: 12 nm)
(C-2): Surface-treated silica filler (product name: SE5200SEE, average particle size 2 μm, manufactured by Admatechs Co., Ltd.)

(D) Acid generators that are salts formed from a gallate anion of formula (1) and a counter cation other than an iodonium cation (represented in the table as "(D) Gallate-based acid generator (other than an iodonium cation)").
(D1-1): A thermal acid generator represented by the following formula:

This thermal acid generator was synthesized according to the method described in WO2018/020974.
(D2-1): a photoacid generator represented by the following formula:

This photoacid generator was synthesized according to the method described in WO2018/020974.
(E) Acid generator other than component (D) (E-1): Thermal acid generator represented by the following formula

(Product name: TA-100, manufactured by San-Apro Co., Ltd.)
(E-2): A thermal acid generator represented by the following formula:

This thermal acid generator was synthesized by the method described in JP-A 2022-080366.
(E-3): Borate-based quaternary ammonium salt (product name: CXC-1821, manufactured by King Industries, Inc., thermal acid generator)
(E-4): Borate-based sulfonium salt (product name: CPI-310B, manufactured by San-Apro Co., Ltd., photoacid generator)

(F) Epoxy compounds other than alicyclic epoxy compounds (F-1): Polypropylene oxide-modified bisphenol A-type epoxy resin (product name: AER9000, manufactured by Asahi Kasei Corporation, epoxy equivalent: 380 g/eq)
(F-2): p-tert-butylphenyl glycidyl ether (product name: ADEKA GLYCIROL (registered trademark) ED-509S, manufactured by ADEKA Corporation, epoxy equivalent: 205 g/eq)
(G) Coupling Agent (G-1): 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (product name: KBM-303, manufactured by Shin-Etsu Chemical Co., Ltd.)
(H) Pigment (H-1): Titanium Black (product name: 13M, manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.)
(I) Other Additives (I-1): Dicetyl peroxydicarbonate (product name: Perkadox (registered trademark) 24L, manufactured by Nouryon)

[Production of cured product]
Each of the resin compositions of the Examples and Comparative Examples was heated at 100° C. for 60 minutes to produce a cured product.

In the examples and comparative examples, the properties of the resin compositions and their cured products were measured as follows.

[Measurement of Tg and Elastic Modulus of Cured Product Before and After PCT]
Each resin composition was applied to a glass substrate to a thickness of 250±100 μm, and the applied sample was subjected to a heat curing treatment at 100°C for 60 minutes in a blower dryer to produce a cured product on the glass substrate. The cured product was subjected to dynamic thermomechanical analysis (DMA) to determine the initial Tg [°C] and elastic modulus at 25°C [GPa] of the cured product.
Thereafter, the cured product was subjected to PCT under conditions of 2 atm, 121°C, 100% RH for 20 hours, and the Tg [°C] and modulus of elasticity [GPa] of the cured product after PCT were determined.
The change in Tg of the cured product before and after PCT was calculated using the following formula.
[Change in Tg of cured product before and after PCT] = |[Initial Tg of cured product] - [Tg of cured product after PCT]|
The modulus of elasticity was measured at 25° C. using a dynamic mechanical analyzer (DMA) manufactured by Hitachi Ltd. in accordance with Japanese Industrial Standard JIS C6481.
The Tg was measured in accordance with Japanese Industrial Standard JIS C6481 using a dynamic mechanical analysis (DMA) device manufactured by Hitachi Ltd.
The results are shown in Table 1.
In this specification, the change in Tg of the cured product before and after PCT under conditions of 2 atm, 121°C, 100% RH, and 20 hours is preferably less than 10.3°C, more preferably 8°C or less, and even more preferably 6°C or less.

The cured products of the resin compositions of Examples 1 to 9 satisfying the constitution of the present invention showed a small change in Tg before and after PCT.
On the other hand, the cured products of the resin compositions of Comparative Examples 1 to 4, which did not contain an acid generator (D), which is a salt formed of a gallate anion of formula (1) and a counter cation other than an iodonium cation, but contained an acid generator (E) other than component (D), showed a large change in Tg before and after PCT.
Surprisingly, the cured product of the resin composition of Example 9, which contained an acid generator other than component (E) (D) in addition to the acid generator (D), which is a salt formed of a gallate anion of formula (1) and a counter cation other than an iodonium cation, showed a small change in Tg before and after PCT, even though it contained an acid generator other than component (E) (D).
(B) The cured product of the resin composition of Comparative Example 5, which did not contain an oxetane compound, also showed a large change in Tg before and after PCT.
Although not shown in Table 1, a similar evaluation was also performed on a two-component resin composition in Example 2, in which component A was component (A), component (C), component (F), component (G), and component (H), and component B was component (B) and component (D), and the results were similar to those of the one-component resin composition.

The resin composition of the present invention is extremely useful, and can be used, for example, as an adhesive or sealant for fixing, joining, or protecting semiconductor devices or electronic components or the components that make them up, or as a raw material for such adhesives or sealants.

The disclosure of Japanese Patent Application No. 2024-048038 (filing date: March 25, 2024) is incorporated herein by reference in its entirety.
All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims (17)

(A) an alicyclic epoxy compound,
(B) an oxetane compound,
(C) a filler, and (D) a compound of the following formula (1):

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 18 carbon atoms or an aryl group having 6 to 14 carbon atoms, provided that at least one of R ₁ , R ₂ , R ₃ and R ₄ represents an aryl group having 6 to 14 carbon atoms.)
and a counter cation other than an iodonium cation. The resin composition according to claim 1, wherein the acid generator (D) is a thermal acid generator (D1). The resin composition according to claim 1, wherein the acid generator (D) is a photoacid generator (D2). The resin composition according to claim 1, wherein the acid generator (D) is a combination of a thermal acid generator (D1) and a photoacid generator (D2). The resin composition according to any one of claims 1 to 4, wherein the counter cation in the acid generator (D) is a sulfonium cation or an ammonium cation. The resin composition according to any one of claims 1 to 5, wherein the content of the acid generator (D) is 0.1 to 10 parts by weight per 100 parts by weight of the total amount of the resin composition. The resin composition according to any one of claims 1 to 6, further comprising (E) an acid generator other than component (D). The resin composition according to claim 7, wherein the acid generator (E) other than component (D) contains a sulfonium cation or an ammonium cation. The resin composition according to any one of claims 1 to 8, further comprising (F) an epoxy compound other than an alicyclic epoxy compound. The resin composition according to claim 9, wherein the (F) epoxy compound other than an alicyclic epoxy compound includes an epoxy compound having an epoxy equivalent of 90 to 1000 g/eq. The resin composition according to claim 9 or 10, wherein the content of the epoxy compound other than the (F) alicyclic epoxy compound is 50 to 200 parts by weight per 100 parts by weight of the (A) alicyclic epoxy compound. The resin composition according to any one of claims 1 to 11, wherein the total content of epoxy compounds contained in the resin composition is 100 to 1,300 parts by weight per 100 parts by weight of the (B) oxetane compound. The resin composition described in any one of claims 1 to 12, wherein components (A) to (D) are contained in a single container. The resin composition described in any one of claims 1 to 12, wherein components (A) to (D) are separated into two or more containers. An adhesive or sealant comprising the resin composition described in any one of claims 1 to 14. A cured product obtained by curing the resin composition described in any one of claims 1 to 14, or the adhesive or sealant described in claim 15. A semiconductor device or electronic component comprising the cured product described in claim 16.