Photocurable composition, pattern forming method and cured film

Abstract

The present invention employs a photocurable composition which contains an acrylic resin (AC), an epoxy group-containing compound (excluding the acrylic resin (AC)), and a cationic polymerization initiator. The acrylic resin (AC) has a glass transition temperature of 0°C or less. This photocurable composition is characterized in that a cured film of this photocurable composition has an elastic modulus of 2.0 × 106 to 1.0 × 109 (Pa) at the temperature of 80°C if determined by viscoelasticity measurement at the frequency of 1 Hz.

Description

[Technical Field]

[0001] The present invention relates to a photocurable composition and a pattern forming method. This application claims priority based on Japanese Patent Application No. 2021-206081, filed in Japan on December 20, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] As the performance of electronic components improves, semiconductor devices are becoming smaller, their operating speeds are increasing, and their wiring density is increasing, leading to the proposal of various packaging forms to address these needs. For example, a package with a hollow structure (hollow package) is being used, in which the wiring substrate on which the electrodes are formed is kept hollow.

[0003] This hollow package can be manufactured as follows. After applying a photosensitive composition to the wiring substrate so as to surround the electrodes, the composition is exposed to light through a photomask, post-exposure baked (PEB), and developed in this order to form side walls that will serve as spacers. Next, a top plate is bonded to the side walls to create a hollow structure. The hollow package is then manufactured by molding.

[0004] As the photosensitive composition, for example, a photocurable adhesive material containing a photocationically polymerizable compound and a polymerization initiator that generates cationic species upon irradiation with light or heating has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-97443 Summary of the Invention [Problem to be solved by the invention]

[0006] In the manufacture of electronic components, various properties are required of photosensitive compositions. When manufacturing the hollow package, the photosensitive composition is used as a material for the sidewalls that serve as spacers. To form the sidewalls, the photosensitive composition is required to have pattern formability that enables the formation of fine patterns with good shapes. The side walls also need to be adhesive to the top plate. In addition, electronic components are naturally required to have durability in the environment in which they are used and to be reliable enough to be used stably and continuously. However, it is difficult for conventional photocurable adhesive materials to satisfy all of these requirements of pattern formability, reliability, and adhesiveness, and further improvements in properties are required.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photocurable composition that has good pattern formability and high reliability, and that can enhance adhesion to an object when formed into a cured film, and a pattern formation method using the same. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following configuration.

[0009] That is, a first aspect of the present invention is a photocurable composition containing an acrylic resin (AC), an epoxy group-containing compound (A) (excluding compounds corresponding to the acrylic resin (AC)), and a cationic polymerization initiator (I), wherein the acrylic resin (AC) has a glass transition point of 0°C or lower, and a cured film obtained by curing the photocurable composition has an elastic modulus of 2.0 × 10 at a temperature of 80°C when viscoelasticity is measured at a frequency of 1 Hz. 6 [Pa] or more 1.0×10 9 The photocurable composition is characterized in that the viscosity is 100 [Pa] or less.

[0010] A second aspect of the present invention is a pattern forming method comprising the steps of: forming a photocurable film on a support using the photocurable composition according to the first aspect; exposing the photocurable film to light; and developing the exposed photocurable film with a developer containing an organic solvent to form a negative pattern. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a photocurable composition that has good pattern formability and high reliability, and that can enhance adhesion to an object when formed into a cured film, and a pattern formation method using the same. DETAILED DESCRIPTION OF THE INVENTION

[0012] In this specification and claims, the term "aliphatic" is a relative concept to aromatic, and is defined to mean a group or compound that does not have aromaticity. Unless otherwise specified, the term "alkyl group" includes linear, branched, and cyclic monovalent saturated hydrocarbon groups. The same applies to alkyl groups in alkoxy groups. Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups. A "halogenated alkyl group" is an alkyl group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and examples of the halogen atoms include fluorine, chlorine, bromine, and iodine atoms. The term "fluorinated alkyl group" refers to an alkyl group in which some or all of the hydrogen atoms have been substituted with fluorine atoms. The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer). The phrase "optionally substituted" includes both cases where a hydrogen atom (-H) is replaced with a monovalent group and where a methylene group (-CH2-) is replaced with a divalent group. The term "exposure" is a general concept that includes irradiation with radiation.

[0013] (Photocurable composition) The photocurable composition of this embodiment contains an acrylic resin (AC), an epoxy group-containing compound (A) (excluding those corresponding to the acrylic resin (AC)), and a cationic polymerization initiator (I). Hereinafter, the acrylic resin (AC), the epoxy group-containing compound (A), and the cationic polymerization initiator (I) may also be referred to as component (AC), component (A), and component (I), respectively.

[0014] When a photocurable film is formed using this photocurable composition and selectively exposed to light, the cationic moiety of component (I) decomposes in the exposed area of ​​the photocurable film to generate an acid, and the action of this acid causes the epoxy group in component (A) to undergo ring-opening polymerization, reducing the solubility of component (A) in a developer containing an organic solvent. Meanwhile, the solubility of component (A) in a developer containing an organic solvent remains unchanged in the unexposed area of ​​the photocurable film, resulting in a difference in solubility in a developer containing an organic solvent between the exposed area and the unexposed area of ​​the photocurable film. Therefore, when the photocurable film is developed with a developer containing an organic solvent, the unexposed area is dissolved and removed, forming a negative pattern.

[0015] <Acrylic resin (AC)> The acrylic resin (AC) contained in the photocurable composition of this embodiment has a glass transition point of 0° C. or lower.

[0016] "Acrylic resin (AC)" refers to a polymer produced by polymerizing at least an acrylic acid ester as a monomer. In the "acrylate ester," the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. αx ) is an atom or group other than a hydrogen atom. Note that the carbon atom at the α-position of an acrylic ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded, unless otherwise specified. Substituent (R αx) includes an alkyl group having 1 to 5 carbon atoms, a halogen atom, or a halogenated alkyl group having 1 to 5 carbon atoms.

[0017] The glass transition point Tg of the acrylic resin is calculated by the following formula (Fox's formula). 1 / (Tg+273) ={W1 / (Tg1+273)+W2 / (Tg2+273)+···} / 100 Tg: Glass transition temperature of the acrylic copolymer (℃) Tg1: Glass transition temperature (°C) of a homopolymer consisting of a repeating structure of structural unit (1) derived from monomer (1) Tg2: Glass transition temperature (°C) of a homopolymer consisting of a repeating structure of structural unit (2) derived from monomer (2) W1: Proportion (mass%) of structural unit (1) constituting acrylic resin W2: Proportion (mass%) of structural unit (2) constituting acrylic resin W1+W2+=100

[0018] The glass transition temperatures of homopolymers are those disclosed on the KTR (Kaji Test Research) website (www.kaji-tr.com), the Polymer Materials Handbook (edited by the Society of Polymer Science, Corona Publishing, first edition, published February 20, 1973), the Acrylic Products Catalog of Kyoeisha Chemical Co., Ltd., and the Polymer Data Handbook Basics (edited by the Society of Polymer Science, Baifukan Publishing, published January 30, 1986).

[0019] For example, the glass transition temperature Tg (°C) of an acrylic resin that is a copolymer of a structural unit derived from 2-methoxyethyl acrylate and a structural unit derived from n-butyl acrylate can be calculated as follows. Monomer (1) is 2-methoxyethyl acrylate. A homopolymer consisting of a repeating structure of structural unit (1) derived from this monomer (1) has a glass transition temperature of -50°C and contains 73% by mass of structural unit (1). Monomer (2) is n-butyl acrylate. A homopolymer consisting of a repeating structure of structural unit (2) derived from this monomer (2) has a glass transition temperature of −56°C and contains 27% by mass of structural unit (2). The glass transition temperature Tg (°C) of the acrylic resin, which is a copolymer of the structural unit (1) and the structural unit (2), is calculated by the following formula. 1 / (Tg+273) ={73 / (-50+273)+27 / (-56+273)} / 100 Tg ≒ -52℃

[0020] The glass transition temperature Tg of component (AC) is 0°C or lower, preferably from -100°C to 0°C, more preferably from -75°C to -5°C, even more preferably from -65°C to -10°C, and particularly preferably from -55°C to -15°C. If the glass transition temperature Tg of component (AC) is equal to or lower than the upper limit of the above range, the resulting cured film will have improved adhesion to the target object and improved reliability. On the other hand, if the glass transition temperature Tg is equal to or higher than the lower limit of the above range, the strength of the cured film will be increased, making it less likely for the pattern structure to deform. Furthermore, the lithography properties during pattern formation will be improved.

[0021] The glass transition temperature Tg of component (AC) can be controlled by selecting the type of structural unit that constitutes component (AC) and adjusting the content ratio of that structural unit.

[0022] The component (AC) is a polymer formed by polymerizing at least an acrylic acid ester as a monomer, and any polymer having a glass transition point of 0°C or lower may be used. In this embodiment, the polymer preferably contains a structural unit (ac1) derived from an epoxy group-containing acrylic monomer. The presence of the structural unit (ac1) increases the strength of the cured film and reduces the risk of deformation of the pattern structure. Furthermore, the lithography properties during pattern formation are improved. The term "epoxy group-containing acrylic monomer" refers to an acrylic acid ester containing an epoxy group in the side chain. Furthermore, the polymer in this embodiment may also include a structural unit (ac2) other than the structural unit (ac1).

[0023] <Constituent unit (ac1)> The structural unit (ac1) is a structural unit derived from an epoxy group-containing acrylic monomer. The term "structural unit derived from an epoxy group-containing acrylic monomer" refers to a structural unit formed by cleavage of the ethylenic double bond of an epoxy group-containing acrylic monomer.

[0024] Examples of the structural unit (ac1) include structural units containing an epoxy group-containing group in a side chain. The "epoxy group-containing group" referred to here is not particularly limited, and examples include a group consisting of only epoxy groups, a group consisting of only alicyclic epoxy groups, and a group having an epoxy group or alicyclic epoxy group and a divalent linking group.

[0025] The alicyclic epoxy group is an alicyclic group having an oxacyclopropane structure, which is a three-membered ring ether, and specifically, a group having an alicyclic group and an oxacyclopropane structure. The alicyclic group that forms the basic skeleton of the alicyclic epoxy group may be monocyclic or polycyclic. Examples of monocyclic alicyclic groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of polycyclic alicyclic groups include norbornyl, isobornyl, tricyclononyl, tricyclodecyl, and tetracyclododecyl groups. The hydrogen atoms of these alicyclic groups may be substituted with alkyl, alkoxy, or hydroxyl groups. In the case of a group having an epoxy group or an alicyclic epoxy group and a divalent linking group, it is preferable that the epoxy group or the alicyclic epoxy group is linked via the divalent linking group bonded to an oxygen atom (—O—) in the formula.

[0026] Here, the divalent linking group is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

[0027] Regarding optionally substituted divalent hydrocarbon groups: Such a divalent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group in the divalent hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated. More specifically, the aliphatic hydrocarbon group may be a straight-chain or branched-chain aliphatic hydrocarbon group, or an aliphatic hydrocarbon group containing a ring in its structure.

[0028] The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specific examples thereof include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, even more preferably 2 to 4 carbon atoms, and most preferably 2 or 3 carbon atoms. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0029] Examples of the aliphatic hydrocarbon group containing a ring in its structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include the same as those described above. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0030] The aromatic hydrocarbon group in the divalent hydrocarbon group is a hydrocarbon group having at least one aromatic ring. This aromatic ring is not particularly limited as long as it is a cyclic conjugated system having (4n+2) π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, further preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. Specific examples of the aromatic hydrocarbon group include groups in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene groups or heteroarylene groups); groups in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and groups in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., groups in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group such as a benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, or 2-naphthylethyl group). The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1.

[0031] The divalent hydrocarbon group may have a substituent. The linear or branched aliphatic hydrocarbon group as the divalent hydrocarbon group may or may not have a substituent, such as a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, or a carbonyl group.

[0032] The alicyclic hydrocarbon group in the aliphatic hydrocarbon group containing a ring in its structure as a divalent hydrocarbon group may or may not have a substituent, such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, or a carbonyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group. Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred. Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms. In the alicyclic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a heteroatom, and the heteroatom-containing substituent is preferably -O-, -C(=O)-O-, -S-, -S(=O)2-, or -S(=O)2-O-.

[0033] In the aromatic hydrocarbon group as a divalent hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Examples of the alkoxy group, halogen atom and halogenated alkyl group as the substituent include those exemplified as the substituent substituting the hydrogen atom of the alicyclic hydrocarbon group.

[0034] Regarding divalent linking groups containing heteroatoms: The heteroatom in the divalent linking group containing a heteroatom is an atom other than a carbon atom or a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.

[0035] In the divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O-; -C(=O)-NH-, -NH-, -NH-C(=O)-O-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group); -S-, -S(=O)2-, -S(=O)2-O-, and groups represented by the general formula -Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 , -[Y 21 -C(=O)-O] m” -Y 22 -or- Y 21 -OC(=O)-Y 22 -, wherein Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 0 to 3. When the divalent linking group containing a hetero atom is -C(=O)-NH-, -NH-, -NH-C(=O)-O-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group, acyl, etc. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and particularly preferably 1 to 5 carbon atoms. Formula-Y 21 -OY 22 -, -Y 21 -O-, -Y 21 -C(=O)-O-, -C(=O)-OY 21 -, -[Y 21 -C(=O)-O] m” -Y 22 -or- Y 21 -OC(=O)-Y 22 -Medium, Y 21 and Y 22 are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same as the "divalent hydrocarbon group which may have a substituent" listed above in the description of the divalent linking group. Y 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferred, a straight-chain alkylene group is more preferred, a straight-chain alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or ethylene group is particularly preferred. Y 22 is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group. Formula − [Y 21 -C(=O)-O] m” -Y 22 In the group represented by -, m" is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, in the group represented by the formula -[Y 21 -C(=O)-O] m” -Y 22The group represented by - is a group represented by the formula -Y 21 -C(=O)-OY 22 Particularly preferred is a group represented by the formula -(CH2) a’ -C(=O)-O-(CH2) b’ In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

[0036] Of these, the epoxy group-containing group is preferably a glycidyl group.

[0037] Examples of the structural unit (ac1) include epoxy group-containing units represented by the following general formulas (a1-1) and (a1-2).

[0038] [ka] [wherein R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. 41 is a divalent hydrocarbon group which may have a substituent. 41 is an integer between 0 and 2. a41 and R a42 are epoxy group-containing groups. 42 is 0 or 1. 41 is (na 43 +1)valent aliphatic hydrocarbon group. 43 is an integer between 1 and 3.

[0039] In the formula (a1-1), the alkyl group having 1 to 5 carbon atoms for R is preferably linear or branched, 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 tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms in R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being particularly preferred. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

[0040] In the formula (a1-1), Va 41 is a divalent hydrocarbon group which may have a substituent, and examples thereof include the same groups as the divalent hydrocarbon groups which may have a substituent explained above in the "epoxy group-containing group." Among the above, Va 41 The hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably a linear or branched aliphatic hydrocarbon group, still more preferably a linear aliphatic hydrocarbon group, and particularly preferably a linear alkylene group.

[0041] In the formula (a1-1), na 41 is an integer of 0 to 2, with 0 or 1 being preferred.

[0042] In the above formulas (a1-1) and (a1-2), R a41 , R a42 is an epoxy group-containing group, and is the same as the above-mentioned "epoxy group-containing group", and among these, a glycidyl group is preferred.

[0043] In the formula (a1-2), Wa 41 In (na 43 The aliphatic hydrocarbon group having a valence of +1 means a hydrocarbon group having no aromaticity, and may be saturated or unsaturated, but is usually preferably saturated. Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in its structure, and a group in which a linear or branched aliphatic hydrocarbon group and an aliphatic hydrocarbon group containing a ring in its structure are combined.

[0044] In the formula (a1-2), na 43 is an integer of 1 to 3, with 1 or 2 being preferred.

[0045] Specific examples of the structural unit represented by the formula (a1-1) or (a1-2) are shown below. In the following formula, R α represents a hydrogen atom, a methyl group, or a trifluoromethyl group. R a51 represents a divalent hydrocarbon group having 1 to 8 carbon atoms. a52 represents a divalent hydrocarbon group having 1 to 20 carbon atoms. a53 represents a hydrogen atom or a methyl group. 51 is an integer between 0 and 10. R a51 , R a52 , R a53 may be the same or different.

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] [ka]

[0050] The structural unit (ac1) contained in the component (AC) may be of one type, or may be of two or more types. The structural unit (ac1) is preferably an epoxy group-containing unit represented by the above general formula (a1-1).

[0051] When the component (AC) has the structural unit (ac1), the content of the structural unit (ac1) is, for example, more than 0% by mass and less than 50% by mass, relative to the total (100% by mass) of all structural units constituting the component (AC), and is preferably from 0.05% to 40% by mass, more preferably from 0.05% to 20% by mass, even more preferably from 0.10% to 10% by mass, and particularly preferably from 0.20% to 5% by mass. If the content of the structural unit (ac1) is above the lower limit of the above range, the strength of the cured film is increased, making it less likely for the pattern structure to deform. Furthermore, the lithography properties during pattern formation are improved. Furthermore, the chemical resistance of the resin pattern to the chemicals used in the chemical treatment steps included in the manufacturing process of electronic components is enhanced. On the other hand, if the content is below the upper limit of the above range, the adhesiveness to the target object when formed into a cured film is improved, and reliability is also improved.

[0052] <Constituent unit (ac2)> The structural unit (ac2) is a structural unit that constitutes the component (AC) other than the structural unit (ac1) described above. The structural unit (ac2) may be any unit that gives the component (AC) a glass transition point of 0°C or lower, and examples thereof include structural units derived from acrylic esters other than epoxy group-containing acrylic monomers, structural units derived from acrylic acid, and structural units derived from other polymerizable compounds.

[0053] The "acrylic acid ester" and "acrylic acid" referred to here may have a hydrogen atom bonded to the carbon atom at the α-position substituted with a substituent. αx ) includes an alkyl group having 1 to 5 carbon atoms, a halogen atom, or a halogenated alkyl group having 1 to 5 carbon atoms.

[0054] Examples of monomers from which the structural unit (ac2) is derived include (meth)acrylic acid alkyl esters such as 2-ethylhexyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, n-butyl methacrylate, isobutyl methacrylate, ethyl methacrylate, and methyl methacrylate; (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate; (meth)acrylic acid alkoxyalkyl esters such as 2-methoxyethyl acrylate and 2-methoxyethyl methacrylate; monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl maleic acid, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl maleic acid, and 2-methacryloyloxyethyl succinic acid. Examples of suitable polymerizable compounds include methacrylic acid derivatives having a carboxyl group or an ester bond, such as ethyl phthalate and 2-methacryloyloxyethylhexahydrophthalic acid; (meth)acrylic acid aryl esters, such as phenyl acrylate, benzyl acrylate, phenyl methacrylate, and benzyl methacrylate; dicarboxylic acid diesters, such as diethyl maleate and dibutyl fumarate; vinyl group-containing aromatic compounds, such as styrene, α-methylstyrene, chlorostyrene, chloromethylstyrene, vinyltoluene, hydroxystyrene, α-methylhydroxystyrene, and α-ethylhydroxystyrene; vinyl group-containing aliphatic compounds, such as vinyl acetate; conjugated diolefins, such as butadiene and isoprene; nitrile group-containing polymerizable compounds, such as acrylonitrile and methacrylonitrile; chlorine-containing polymerizable compounds, such as vinyl chloride and vinylidene chloride; and amide bond-containing polymerizable compounds, such as acrylamide and methacrylamide. The term "(meth)acrylic acid" means either or both of acrylic acid and methacrylic acid.

[0055] The structural unit (ac2) contained in the component (AC) may be of one type, or may be of two or more types. As the monomer from which the structural unit (ac2) is derived, (meth)acrylic acid alkyl ester, (meth)acrylic acid hydroxyalkyl ester, and (meth)acrylic acid alkoxyalkyl ester are preferred. In the alkyl (meth)acrylate ester, the alkyl in the alkyl ester moiety preferably has 1 to 5 carbon atoms. In the (meth)acrylic acid hydroxyalkyl ester, the alkyl in the hydroxyalkyl ester moiety preferably has 1 to 5 carbon atoms. In the (meth)acrylic acid alkoxyalkyl ester, the alkoxy in the alkoxyalkyl ester moiety preferably has 1 to 3 carbon atoms, and the alkyl preferably has 1 to 5 carbon atoms.

[0056] When the component (AC) contains the structural unit (ac2), the content of the structural unit (ac2) relative to the total (100 mass%) of all structural units constituting the component (AC) is, for example, 50 mass% or more, preferably 60 mass% or more, more preferably 80 mass% or more, even more preferably 90 mass% or more, and particularly preferably 95 mass% or more, or may be 100 mass% (i.e., a polymer composed of repeating structures of one or more types of structural unit (ac2)). When the component (AC) has the structural unit (ac1) and the structural unit (ac2), the content of the structural unit (ac2) relative to the total (100 mass%) of all structural units constituting the component (AC) is, for example, 50 mass% or more, preferably 60 mass% to 99.95 mass% or less, more preferably 80 mass% to 99.95 mass% or less, even more preferably 90 mass% to 99.90 mass% or less, and particularly preferably 95 mass% to 99.80 mass% or less. When the content of the structural unit (ac2) is equal to or greater than the lower limit of the above range, the adhesiveness to the target object can be improved when the cured film is formed, and reliability can also be improved. On the other hand, when the content is equal to or less than the upper limit of the above range, the strength of the cured film is increased, and deformation of the pattern structure is less likely to occur. Furthermore, lithography properties during pattern formation can be improved.

[0057] The acrylic resin (AC) contained in the photocurable composition of this embodiment has a glass transition point of 0° C. or lower, and one type may be used alone, or two or more types may be used in combination. In the (AC) component, the content of structural units derived from "acrylic acid ester" is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total (100% by mass) of all structural units constituting the (AC) component, and may be 100% by mass. Preferred (AC) components include copolymers having the structural unit (ac1) and another structural unit (ac2) and having a glass transition point of 0°C or lower, and polymers having only one or more structural units (ac2) and having a glass transition point of 0°C or lower.

[0058] Preferred copolymers having the structural unit (ac1) and another structural unit (ac2) include copolymers having the structural unit (ac1) and a structural unit derived from a (meth)acrylic acid alkyl ester, copolymers having the structural unit (ac1) and a structural unit derived from a (meth)acrylic acid hydroxyalkyl ester, and copolymers having the structural unit (ac1) and a structural unit derived from a (meth)acrylic acid alkoxyalkyl ester. Alternatively, preferred copolymers having the structural unit (ac1) and another structural unit (ac2) include copolymers having the structural unit (ac1), a structural unit derived from an alkoxyalkyl (meth)acrylate ester, and a structural unit derived from an alkyl (meth)acrylate ester; copolymers having the structural unit (ac1), a structural unit derived from an alkoxyalkyl (meth)acrylate ester, and a structural unit derived from a hydroxyalkyl (meth)acrylate ester; and copolymers having the structural unit (ac1), a structural unit derived from a hydroxyalkyl (meth)acrylate ester, and a structural unit derived from an alkyl (meth)acrylate ester.

[0059] For example, in a copolymer having the structural unit (ac1) and another structural unit (ac2), relative to the total (100% by mass) of all structural units constituting the copolymer, the content of the structural unit (ac1) is greater than 0% by mass and 5% by mass or less, the content of structural units derived from (meth)acrylic acid alkoxyalkyl ester is 30% by mass or more and 99% by mass or less, the content of structural units derived from (meth)acrylic acid hydroxyalkyl ester is 0.5% by mass or more and 5% by mass or less, and the content of structural units derived from (meth)acrylic acid alkyl ester is 20% by mass or more and 70% by mass or less.

[0060] Preferred polymers containing only the structural unit (ac2) include copolymers containing structural units derived from an alkoxyalkyl (meth)acrylate ester and structural units derived from an alkyl (meth)acrylate ester, copolymers containing structural units derived from a hydroxyalkyl (meth)acrylate ester and structural units derived from an alkyl (meth)acrylate ester, and copolymers containing structural units derived from an alkoxyalkyl (meth)acrylate ester and structural units derived from a hydroxyalkyl (meth)acrylate ester.

[0061] For example, in a polymer having only the structural unit (ac2), relative to the total (100 mass%) of all structural units constituting the copolymer, the content of structural units derived from an alkoxyalkyl (meth)acrylate is from 30 mass% to 99 mass%; the content of structural units derived from a hydroxyalkyl (meth)acrylate is from 0.5 mass% to 5 mass%; and the content of structural units derived from an alkyl (meth)acrylate is from 20 mass% to 80 mass%.

[0062] The component (AC) can be produced by dissolving a monomer from which the structural unit (ac1) is derived and a monomer from which the structural unit (ac2) is derived, or a monomer from which the structural unit (ac2) is derived, in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601), and carrying out polymerization.

[0063] The weight average molecular weight (Mw) of the component (AC) (measured by gel permeation chromatography (GPC) and converted into standard polystyrene) is not particularly limited, but is preferably 20,000 to 400,000, more preferably 50,000 to 380,000, and even more preferably 100,000 to 360,000. The dispersity (Mw / Mn) of the component (AC) is not particularly limited, but is preferably from 1.0 to 3.0, more preferably from 1.0 to 2.5, and particularly preferably from 1.0 to 2.0, where Mn represents the number average molecular weight.

[0064] In the photocurable composition of this embodiment, the content of the component (AC) is preferably 1 to 150 parts by mass, more preferably 5 to 100 parts by mass, even more preferably 10 to 75 parts by mass, and particularly preferably 10 to 50 parts by mass, relative to 100 parts by mass of the epoxy group-containing compound (A) described below.

[0065] In the photocurable composition of this embodiment, the content of component (AC) is preferably 1 to 60 mass%, more preferably 3 to 50 mass%, even more preferably 5 to 40 mass%, and particularly preferably 5 to 30 mass%, relative to the total solid content (100 mass%) of the photocurable composition.

[0066] <Epoxy group-containing compound (A)> The epoxy group-containing compound (A) contained in the photocurable composition of this embodiment may be a compound having enough epoxy groups in one molecule to form a negative pattern by exposure. Examples of such component (A) include novolac epoxy resins (hereinafter also referred to as "component (A1)"), bisphenol epoxy resins (hereinafter also referred to as "component (A2)"), and aliphatic epoxy resins. The component (A) may be used alone or in combination of two or more. However, the component (A) does not include those that fall under the category of the acrylic resin (AC).

[0067] <Novolac epoxy resin> Suitable examples of novolac epoxy resins (component (A1)) include epoxy resins represented by the following general formula (anv0).

[0068] [ka] [In the formula, R p1 and R p2 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. p1 may be the same or different. p2 may be the same or different. n1 is an integer of 1 to 5. R EP is an epoxy group-containing group. EP may be the same or different from each other.

[0069] In the formula (anv0), R p1 , R p2 The alkyl group having 1 to 5 carbon atoms is, for example, a linear, branched, or cyclic alkyl group having 1 to 5 carbon atoms. Examples of the linear or branched alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. Examples of the cyclic alkyl group include a cyclobutyl group and a cyclopentyl group. Among them, R p1 , R p2As the alkyl group, a hydrogen atom or a linear or branched alkyl group is preferred, a hydrogen atom or a linear alkyl group is more preferred, and a hydrogen atom or a methyl group is particularly preferred. In the formula (anv0), multiple R p1 may be the same or different. p2 may be the same as or different from each other.

[0070] In the formula (anv0), n1 is an integer of 1 to 5, preferably 2 or 3, and more preferably 2.

[0071] In the formula (anv0), R EP is an epoxy group-containing group. R EP The epoxy group-containing group is not particularly limited, and examples thereof include a group consisting of only epoxy groups; a group consisting of only alicyclic epoxy groups; and a group having an epoxy group or alicyclic epoxy group and a divalent linking group. R EP The explanation of the epoxy group-containing group is the same as the explanation of the "epoxy group-containing group" above. Among them, R EP The epoxy group-containing group in is preferably a glycidyl group.

[0072] Additionally, suitable examples of the component (A1) include resins having a structural unit represented by the following general formula (anv1):

[0073] [ka] [In the formula, R EP is an epoxy group-containing group. a22 and R a23 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom.

[0074] In the formula (anv1), R a22 , R a23 The alkyl group having 1 to 5 carbon atoms is Rp1 , R p2 The alkyl group has 1 to 5 carbon atoms. R a22 , R a23 The halogen atom is preferably a chlorine atom or a bromine atom. In the formula (anv1), R EP is R in the above formula (anv0). EP and a glycidyl group is preferred.

[0075] Specific examples of the constitutional unit represented by the formula (anv1) are shown below.

[0076] [ka]

[0077] The component (A1) may be a resin consisting solely of the structural unit (anv1), or it may be a resin containing the structural unit (anv1) in addition to other structural units. Examples of other structural units include structural units represented by the following general formulas (anv2) to (anv3).

[0078] [ka] [In the formula, R a24 R is a hydrocarbon group which may have a substituent. a25 ~R a26 , R a28 ~R a30 R are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom. a27 represents an epoxy group-containing group or a hydrocarbon group which may have a substituent.

[0079] In the formula (anv2), R a24 is a hydrocarbon group which may have a substituent. Examples of the hydrocarbon group which may have a substituent include a linear or branched alkyl group, and a cyclic hydrocarbon group. The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, and even more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, etc. Among these, a methyl group, an ethyl group, or an n-butyl group is preferred, and a methyl group or an ethyl group is more preferred.

[0080] The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, with an isopropyl group being preferred.

[0081] R a24 When is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group. The monocyclic aliphatic hydrocarbon group is preferably a group in which one hydrogen atom has been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The aliphatic hydrocarbon group that is a polycyclic group is preferably a group in which one hydrogen atom has been removed from a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specific examples of which include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

[0082] R a24 When the cyclic hydrocarbon group is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, even more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Examples of heteroatoms in the aromatic heterocycle include oxygen atoms, sulfur atoms, and nitrogen atoms. Specific examples of the aromatic heterocycle include pyridine rings and thiophene rings. R a24 Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (an aryl group or a heteroaryl group); a group in which one hydrogen atom has been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); and a group in which one hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocycle has been substituted with an alkylene group (e.g., an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1.

[0083] In the formulas (anv2) and (anv3), R a25 ~R a26 , R a28 ~R a30 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom. The alkyl group having 1 to 5 carbon atoms and the halogen atom are each defined as R a22 , R a23 is the same as:

[0084] In the formula (anv3), R a27 R is an epoxy group-containing group or a hydrocarbon group which may have a substituent. a27The epoxy group-containing group is R EP Similar to R a27 The hydrocarbon group which may have a substituent is R a24 is the same as:

[0085] Specific examples of the structural units represented by the formulae (anv2) to (anv3) are shown below.

[0086] [ka]

[0087] When the component (A1) contains other structural units in addition to the structural unit (anv1), there are no particular limitations on the proportion of each structural unit within the component (A1), but the total amount of structural units having an epoxy group relative to the total amount of all structural units constituting the component (A1) is preferably 10 to 90 mol %, more preferably 20 to 80 mol %, and even more preferably 30 to 70 mol %.

[0088] Commercially available products of the component (A1) include, for example, novolac epoxy resins such as jER-152, jER-154, jER-157S70, and jER-157S65 (all manufactured by Mitsubishi Chemical Corporation), EPICLON N-740, EPICLON N-740, EPICLON N-770, EPICLON N-775, EPICLON N-660, EPICLON N-665, EPICLON N-670, EPICLON N-673, EPICLON N-680, EPICLON N-690, EPICLON N-695, and EPICLON HP5000 (all manufactured by DIC Corporation), the YDPN and YDCN series (all manufactured by Nippon Steel & Sumitomo Metal Corporation), and EOCN-1020 (manufactured by Nippon Kayaku Co., Ltd.).

[0089] As the component (A1), one type may be used alone, or two or more types may be used in combination. In the photocurable composition of this embodiment, the content of the component (A1) is preferably 25% by mass or more, more preferably 40% by mass or more, based on 100% by mass of the total amount of the component (A), and may be 50% by mass or more, 75% by mass or more, 90% by mass or more, or even 100% by mass.

[0090] <Bisphenol-type epoxy resin> The bisphenol-type epoxy resin (hereinafter also referred to as "component (A2)") may be any resin having a structural unit containing a bisphenol skeleton, and among these, solid bisphenol-type epoxy resins are preferred. The solid bisphenol epoxy resin refers to a resin that is solid at 25°C and has a structural unit containing a bisphenol skeleton. The epoxy equivalent of the component (A2) is, for example, preferably 500 g / eq. or more, more preferably 550 to 1200 g / eq., and even more preferably 600 to 1000 g / eq.

[0091] Suitable examples of the component (A2) include epoxy resins represented by the following general formula (abp1):

[0092] [ka] [In the formula, R EP is an epoxy group-containing group. EP may be the same or different. a31 and R a32 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms. 31 is an integer between 1 and 50.

[0093] In the formula (abp1), R EP is R in the above formula (anv0). EP and a glycidyl group is preferred. In the formula (abp1), R a31 , R a32The alkyl group having 1 to 5 carbon atoms in the formula (anv0) is R p1 , R p2 The alkyl groups having 1 to 5 carbon atoms are the same as those in the above. a31 , R a32 are each preferably a hydrogen atom or a methyl group. R a31 , R a32 The fluorinated alkyl group having 1 to 5 carbon atoms in a31 , R a32 Examples of such groups include groups in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with fluorine atoms. In the formula (abp1), na 31 is an integer of 1 to 50, preferably an integer of 4 to 15, and more preferably an integer of 5 to 8.

[0094] Examples of commercially available products that can be used as component (A2) include jER-4005, jER-4007, and jER-4010 (all manufactured by Mitsubishi Chemical Corporation); jER-827, jER-828, jER-834, jER-1001, jER-1002, jER-1003, jER-1055, jER-1007, jER-1009, and jER-1010 (all manufactured by Mitsubishi Chemical Corporation); and EPICLON860, EPICLON1050, EPICLON1051, and EPICLON1055 (all manufactured by DIC Corporation).

[0095] As the component (A2), one type may be used alone, or two or more types may be used in combination. In the photocurable composition of this embodiment, the content of the component (A2) is preferably 50% by mass or more, more preferably 60% by mass or more, and may be 70% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass, relative to 100% by mass of the total amount of the component (A).

[0096] When the (A1) component and the (A2) component are used in combination, the mass ratio of the (A1) component to the (A2) component, expressed as the (A1) component / (A2) component, is preferably 3 / 7 or more and 7 / 3 or less, more preferably 4 / 6 or more and 6 / 4 or less, and even more preferably 5 / 5. When the mass ratio is within the above-mentioned preferred range, the strength of the cured film can be easily adjusted, and the effects of the present invention can be more easily obtained.

[0097] <Aliphatic epoxy resin> Suitable examples of aliphatic epoxy resins include compounds represented by the following general formula (ta1) (hereinafter, this compound may also be referred to as "component (A3)"):

[0098] [ka] [In the formula, R EP is an epoxy group-containing group. EP may be the same or different from each other.

[0099] In the formula (ta1), R EP is an epoxy group-containing group, and R in the formula (anv0) EP is the same as:

[0100] Commercially available products that can be used as the component (A3) include, for example, the TEPIC series (manufactured by Nissan Chemical Industries, Ltd.), such as TEPIC, TEPIC-VL, TEPIC-PAS, TEPIC-G, TEPIC-S, TEPIC-SP, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-FL, and TEPIC-UC; and MA-DGIC, DA-MGIC, and TOIC (manufactured by Shikoku Chemical Industries, Ltd.). As the component (A3), one type may be used alone, or two or more types may be used in combination.

[0101] The aliphatic epoxy resin also includes a compound containing a partial structure represented by the following general formula (m1) (hereinafter also referred to as "component (m1)").

[0102] [ka] [In the formula, n2 is an integer of 1 to 4. * indicates a bond.]

[0103] In the formula (m1), n2 is an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 2.

[0104] Examples of the component (m1) include compounds in which a plurality of partial structures represented by the general formula (m1) are bonded via a divalent linking group or a single bond. Among these, compounds in which a plurality of partial structures represented by the general formula (m1) are bonded via a divalent linking group are preferred. The divalent linking group here is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom. Here, the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom are the same as the divalent hydrocarbon group which may have a substituent and the divalent linking group which contains a hetero atom explained above in the "epoxy group-containing group", and among these, the divalent linking group which contains a hetero atom is preferred, and -Y 21 a group represented by —C(═O)—O—, —C(═O)—OY 21 A group represented by Y - is more preferred. 21 As the alkyl group, a straight-chain aliphatic hydrocarbon group is preferred, a straight-chain alkylene group is more preferred, a straight-chain alkylene group having 1 to 5 carbon atoms is even more preferred, and a methylene group or ethylene group is particularly preferred.

[0105] Commercially available aliphatic epoxy resins include ADEKA RESIN EP-4080S, EP-4085S, and EP-4088S (manufactured by ADEKA Corporation); CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2083, CELLOXIDE 2085, CELLOXIDE 8000, CELLOXIDE 8010, EHPE-3150, EPOLEAD PB 3600, and EPOLEAD PB 4700 (manufactured by Daicel Corporation); and DENACOL EX-211L, EX-212L, EX-214L, EX-216L, EX-321L, and EX-850L (manufactured by Nagase ChemteX Corporation).

[0106] In addition to the above-mentioned resins, the epoxy group-containing compound (A) may also include compounds represented by the following chemical formula (A4-1) and compounds represented by the following chemical formula (A4-2). An example of a commercially available product that can be used as the compound represented by the following chemical formula (A4-1) is TECHMORE VG-3101L (manufactured by Printec Co., Ltd.). Examples of commercially available products that can be used as the compound represented by the following chemical formula (A4-2) include Showfree (registered trademark) BATG (manufactured by Showa Denko KK).

[0107] [ka]

[0108] Examples of the epoxy group-containing compound (A) include trimethylolpropane triglycidyl ether, glycerin triglycidyl ether; pentaerythritol tetraglycidyl ether, ditrimethylolpropane tetraglycidyl ether, diglycerin tetraglycidyl ether, erythritol tetraglycidyl ether; xylitol pentaglycidyl ether, dipentaerythritol pentaglycidyl ether, inositol pentaglycidyl ether; dipentaerythritol hexaglycidyl ether, sorbitol hexaglycidyl ether, and inositol hexaglycidyl ether.

[0109] In the photocurable composition of this embodiment, the component (A) preferably contains at least one epoxy resin selected from the group consisting of bisphenol-type epoxy resins (A2) and novolac-type epoxy resins (A1). Among these, the component (A) is more preferably one containing a solid bisphenol-type epoxy resin and the component (A1), and is further preferably one containing an epoxy resin represented by general formula (abp1) and an epoxy resin represented by general formula (anv0); or one containing an epoxy resin represented by general formula (abp1) and an epoxy resin represented by general formula (anv1).

[0110] The polystyrene-equivalent weight average molecular weight of component (A) is preferably 100 to 300000, more preferably 200 to 200000, and even more preferably 300 to 200000. By ensuring that the weight average molecular weight is within this range, the strength of the cured film that is formed can be sufficiently increased.

[0111] The content of the component (A) in the photocurable composition of this embodiment may be adjusted depending on the film thickness of the photocurable film to be formed. In the photocurable composition of this embodiment, the content of component (A) is preferably 40 to 99 mass%, more preferably 50 to 95 mass%, and even more preferably 60 to 90 mass%, relative to the total solid content (100 mass%) of the photocurable composition.

[0112] In the photocurable composition of this embodiment, the mixing ratio of the acrylic resin (AC) to the epoxy group-containing compound (A), as a mass ratio, is preferably (A) component / (AC) component=40 / 60 to 95 / 5, more preferably 50 / 50 to 90 / 10, and even more preferably 60 / 40 to 90 / 10. When the mass ratio is equal to or greater than the lower limit of the preferred range, the elastic modulus of the cured film increases, resulting in increased strength of the cured film and less deformation of the pattern structure. Furthermore, the lithography properties during pattern formation are improved. On the other hand, when the mass ratio is equal to or less than the upper limit of the preferred range, the cured film tends to have improved adhesion to the target object.

[0113] <Cationic Polymerization Initiator (I)> The cationic polymerization initiator (I) contained in the photocurable composition of this embodiment is a compound that generates cations when irradiated with active energy rays such as ultraviolet rays, far ultraviolet rays, excimer laser light such as KrF or ArF, X-rays, or electron beams, and the cations can serve as polymerization initiators. Examples of this component (I) include onium borate salts (hereinafter also referred to as "component (I1)"), compounds represented by the general formula (I2-1) or (I2-2) described below (hereinafter also referred to as "component (I2)"), and compounds represented by the general formula (I3-1) or (I3-2) described below (hereinafter also referred to as "component (I3)").

[0114] Onium borate salts Onium borate salts (component (I1)) generate a relatively strong acid upon exposure to light. Therefore, by forming a pattern using a photocurable composition containing component (I1), sufficient sensitivity is achieved, resulting in the formation of a good pattern. Furthermore, the use of component (I1) reduces the risk of toxicity and metal corrosion. Suitable examples of the component (I1) include compounds represented by the following general formula (I1).

[0115] [ka] [In the formula, R b01 ~R b04 are each independently an aryl group which may have a substituent, or a fluorine atom; q is an integer of 1 or more; q+ is a q-valent organic cation.

[0116] Anion section In the formula (I1), R b01 ~R b04 The aryl group in the formula (I) preferably has 5 to 30 carbon atoms, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples include a naphthyl group, a phenyl group, and an anthracenyl group, with a phenyl group being preferred because of its easy availability. R b01 ~R b04 The aryl group in may have a substituent. The substituent is not particularly limited, but is preferably a halogen atom, a hydroxyl group, an alkyl group (preferably a linear or branched alkyl group, preferably having 1 to 5 carbon atoms), or a halogenated alkyl group, more preferably a halogen atom or a halogenated alkyl group having 1 to 5 carbon atoms, and particularly preferably a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. When the aryl group has a fluorine atom, the polarity of the anion moiety is enhanced, which is preferable. Among them, R in formula (I1) b01 ~R b04 As each of the groups, a fluorinated phenyl group is preferred, and a perfluorophenyl group is particularly preferred.

[0117] A preferred example of the anion moiety of the compound represented by formula (I1) is tetrakis(pentafluorophenyl)borate ([B(C6F5)4] - );Tetrakis[(trifluoromethyl)phenyl]borate ([B(C6H4CF3)4] - );Difluorobis(pentafluorophenyl)borate ([(C6F5)2BF2] - ); Trifluoro(pentafluorophenyl)borate ([(C6F5)BF3] - );Tetrakis(difluorophenyl)borate ([B(C6H3F2)4] - ) etc. Among them, tetrakis(pentafluorophenyl)borate ([B(C6F5)4] - ) is particularly preferred.

[0118] Cation part In the formula (I1), Q q+ Suitable examples of the cation include sulfonium cations and iodonium cations, and organic cations represented by the following general formulas (ca-1) to (ca-5) are particularly preferred.

[0119] [ka] [In the formula, R 201 ~R 207 , and R 211 ~R 212 R each independently represents an aryl group, a heteroaryl group, an alkyl group, or an alkenyl group, which may have a substituent. 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 may be bonded to each other to form a ring together with the sulfur atom in the formula. 208 ~R 209 R each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. 201 represents -C(=O)- or -C(=O)-O-. Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. x is 1 or 2. W 201 represents a (x+1)-valent linking group.

[0120] R 201 ~R 207 , and R 211 ~R 212 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 201 ~R 207 , and R 211 ~R 212Examples of the heteroaryl group in the above formula (I) include those in which some of the carbon atoms constituting the aryl group have been substituted with heteroatoms. Examples of heteroatoms include oxygen atoms, sulfur atoms, and nitrogen atoms. Examples of this heteroaryl group include a group in which one hydrogen atom has been removed from 9H-thioxanthene; examples of the substituted heteroaryl group include a group in which one hydrogen atom has been removed from 9H-thioxanthen-9-one. R 201 ~R 207 , and R 211 ~R 212 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 201 ~R 207 , and R 211 ~R 212 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms. R 201 ~R 207 , and R 210 ~R 212 Examples of the substituent that may be possessed by the group include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an oxo group (═O), an aryl group, and groups represented by the following formulas (ca-r-1) to (ca-r-10):

[0121] [ka] [In the formula, R' 201 are each independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group.

[0122] In the above formulas (ca-r-1) to (ca-r-10), R' 201 are each independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted chain alkenyl group.

[0123] Optionally substituted cyclic groups: The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or a cyclic aliphatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. Furthermore, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

[0124] R' 201 The aromatic hydrocarbon group in the formula (I) is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. However, the number of carbon atoms does not include the number of carbon atoms in the substituent. R' 201 Specific examples of the aromatic ring possessed by the aromatic hydrocarbon group in the above formula include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which some of the carbon atoms constituting these aromatic rings are substituted with heteroatoms, or rings in which some of the hydrogen atoms constituting these aromatic rings or aromatic heterocycles are substituted with oxo groups, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. R' 201Specific examples of the aromatic hydrocarbon group in the formula (I) include a group in which one hydrogen atom has been removed from the aromatic ring (an aryl group: for example, a phenyl group, a naphthyl group, or an anthracenyl group); a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group); a group in which one hydrogen atom has been removed from a ring in which some of the hydrogen atoms constituting the aromatic ring have been substituted with an oxo group or the like (for example, anthraquinone); and a group in which one hydrogen atom has been removed from an aromatic heterocycle (for example, 9H-thioxanthene or 9H-thioxanthen-9-one). The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1.

[0125] R' 201 The cyclic aliphatic hydrocarbon group in the formula (I) is an aliphatic hydrocarbon group containing a ring in the structure. Examples of aliphatic hydrocarbon groups that contain a ring in their structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is interposed in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among these, the polycycloalkane is more preferably a polycycloalkane having a bridged ring polycyclic skeleton, such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a fused ring polycyclic skeleton, such as a cyclic group having a steroid skeleton.

[0126] Among them, R' 201 The cyclic aliphatic hydrocarbon group in is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group or a norbornyl group, and most preferably an adamantyl group.

[0127] The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferred, and specific examples include a methylene group [-CH2-], an ethylene group [-(CH2)2-], a trimethylene group [-(CH2)3-], a tetramethylene group [-(CH2)4-], and a pentamethylene group [-(CH2)5-]. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof include alkyl alkylene groups such as alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; alkylethylene groups such as -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, and -C(CH2CH3)2-CH2-; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; and alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-. The alkyl group in the alkylalkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

[0128] An optionally substituted chain alkyl group: R' 201 The chain alkyl group may be either a straight chain or a branched chain. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a heneicosyl group, and a docosyl group. The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0129] An optionally substituted chain alkenyl group: R' 201 The chain alkenyl group may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5, even more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylvinyl group, a 2-methylvinyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group. Of the chain alkenyl groups mentioned above, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

[0130] R' 201 Examples of the substituent in the cyclic group, chain alkyl group or alkenyl group include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, an oxo group, the above-mentioned R' 201 Examples of the groups include a cyclic group, an alkylcarbonyl group, and a thienylcarbonyl group.

[0131] Among them, R' 201 is preferably a cyclic group which may have a substituent, or a chain alkyl group which may have a substituent.

[0132] R 201 ~R 203 , R 206 ~R 207 , R 211 ~R 212 When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may not contain a heteroatom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or a carbonyl group, -SO-, -SO2-, -SO3-, -COO-, -CONH-, or -N(R N )-(applicable R Nis an alkyl group having 1 to 5 carbon atoms.) The ring formed is preferably a 3- to 10-membered ring, including the sulfur atom, and particularly preferably a 5- to 7-membered ring, inclusive of the sulfur atom. Specific examples of the ring formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

[0133] In the formula (ca-3), R 208 ~R 209 each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when they are alkyl groups, they may be bonded to each other to form a ring.

[0134] In the formula (ca-3), R 210 is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted -SO2- containing cyclic group. R 210 The aryl group in the formula (I) includes an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group or a naphthyl group is preferred. R 210 The alkyl group in the formula (I) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms. R 210 The alkenyl group in the formula (I) preferably has 2 to 10 carbon atoms.

[0135] In the formula (ca-4) and formula (ca-5), Y 201 each independently represents an arylene group, an alkylene group, or an alkenylene group. Y 201 The arylene group in R' 201Examples of the aromatic hydrocarbon group in the above formula include groups in which one hydrogen atom has been removed from the aryl groups exemplified above. Y 201 The alkylene group and alkenylene group in R' 201 Examples of the chain alkyl group and chain alkenyl group include groups in which one hydrogen atom has been removed from the groups exemplified above as the chain alkyl group and chain alkenyl group.

[0136] In the above formulas (ca-4) and (ca-5), x is 1 or 2. W 201 is an (x+1)-valent, i.e., a divalent or trivalent linking group. W 201 The divalent linking group in W is preferably a divalent hydrocarbon group which may have a substituent, and is preferably the same as the divalent hydrocarbon group which may have a substituent exemplified above in the "epoxy group-containing group." 201 The divalent linking group in may be linear, branched, or cyclic, and is preferably cyclic. Among them, a group in which two carbonyl groups are combined at both ends of an arylene group, or a group consisting of an arylene group alone is preferred. Examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is particularly preferred. W 201 The trivalent linking group in 201 Examples of the divalent linking group include a group in which one hydrogen atom has been removed from the divalent linking group shown in the formula (1), and a group in which the divalent linking group is further bonded to the divalent linking group shown in the formula (1). 201 The trivalent linking group in the formula (I) is preferably a group in which two carbonyl groups are bonded to an arylene group.

[0137] Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following formulas (ca-1-1) to (ca-1-24).

[0138] [ka]

[0139] [ka] [In the formula, R” 201 is a hydrogen atom or a substituent. The substituent includes the above-mentioned R 201 ~R 207 and R 210 ~R 212 The substituents are the same as those exemplified as the substituents that may be possessed by the group

[0140] As the cation represented by the formula (ca-1), cations represented by the following general formulas (ca-1-25) to (ca-1-35) are also preferred.

[0141] [ka]

[0142] [ka] [In the formula, R' 211 is an alkyl group. hal is a hydrogen atom or a halogen atom.

[0143] As the cation represented by the formula (ca-1), cations represented by the following chemical formulas (ca-1-36) to (ca-1-48) are also preferred.

[0144] [ka]

[0145] Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cation, bis(4-tert-butylphenyl)iodonium cation, and the like.

[0146] Specific examples of suitable cations represented by the formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

[0147] [ka]

[0148] Specific examples of suitable cations represented by the formula (ca-4) include cations represented by the following formulas (ca-4-1) to (ca-4-2).

[0149] [ka]

[0150] As the cation represented by the formula (ca-5), cations represented by the following general formulas (ca-5-1) to (ca-5-3) are also preferred.

[0151] [ka] [In the formula, R' 212 R' is an alkyl group or a hydrogen atom. 211 is an alkyl group.

[0152] Among the above, the cation part [(Q q+ ) 1 / q ] is preferably a cation represented by general formula (ca-1), more preferably a cation represented by each of formulas (ca-1-1) to (ca-1-48), and even more preferably a cation represented by formula (ca-1-25), (ca-1-29), (ca-1-35), (ca-1-47), or (ca-1-48).

[0153] Specific examples of suitable components (I1) are listed below.

[0154] [ka]

[0155] ≪(I2) component≫ The component (I2) is a compound represented by the following general formula (I2-1) or (I2-2). The component (I2) generates a relatively strong acid upon exposure to light, and therefore, when a photocurable composition containing the component (I) is used to form a pattern, sufficient sensitivity is obtained and a good pattern is formed.

[0156] [ka] [In the formula, R b05 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b05 may be the same or different from each other. q is an integer of 1 or more, and Q q+ is a q-valent organic cation.

[0157] [ka] [In the formula, R b06 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b06 may be the same or different from each other. q is an integer of 1 or more, and Q q+ is a q-valent organic cation.

[0158] Anion section In the above formula (I2-1), R b05 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b05 may be the same as or different from each other. R b05 The fluorinated alkyl group in the formula (I) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and even more preferably 1 to 5. Specific examples include alkyl groups having 1 to 5 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms. Among them, R b05is preferably a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms, more preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and further preferably a fluorine atom, a trifluoromethyl group or a pentafluoroethyl group.

[0159] The anion moiety of the compound represented by formula (I2-1) is preferably represented by the following general formula (b0-2a).

[0160] [ka] [In the formula, R bf05 nb is a fluorinated alkyl group which may have a substituent. 1 is an integer between 1 and 5.

[0161] In formula (b0-2a), R bf05 The optionally substituted fluorinated alkyl group in R b05 The same applies to the optionally substituted fluorinated alkyl groups listed in the above. In formula (b0-2a), nb 1 is preferably an integer of 1 to 4, more preferably an integer of 2 to 4, and most preferably 3.

[0162] In the above formula (I2-2), R b06 is a fluorine atom or a fluorinated alkyl group which may have a substituent. b06 may be the same as or different from each other. R b06 The fluorinated alkyl group in the formula (I) preferably has 1 to 10 carbon atoms, more preferably 1 to 8, and even more preferably 1 to 5. Specific examples include alkyl groups having 1 to 5 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms. Among them, R b06 As the alkyl group, a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms is preferred, a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms is more preferred, and a fluorine atom is even more preferred.

[0163] Cation part In formula (I2-1) and formula (I2-2), q is an integer of 1 or more, and Q q+ is a q-valent organic cation. This Q q+ As the Q in the above formula (I1), q+ Among these, cations represented by general formula (ca-1) are preferred, with cations represented by formulas (ca-1-1) to (ca-1-48) being more preferred, and cations represented by formula (ca-1-25), (ca-1-29), (ca-1-35), and (ca-1-47) being even more preferred.

[0164] Specific examples of suitable components (I2) are listed below.

[0165] [ka]

[0166] <Component (I3)> The component (I3) is a compound represented by the following general formula (I3-1) or (I3-2).

[0167] [ka] [In the formula, R b11 ~R b12 is a cyclic group which may have a substituent other than a halogen atom, a chain alkyl group which may have a substituent other than a halogen atom, or a chain alkenyl group which may have a substituent other than a halogen atom. m is an integer of 1 or more, and M m+ are each independently an m-valent organic cation.

[0168] {Component (I3-1)} Anion section In formula (I3-1), R b12is a cyclic group which may have a substituent other than a halogen atom, a chain alkyl group which may have a substituent other than a halogen atom, or a chain alkenyl group which may have a substituent other than a halogen atom, and R' 201 Among the cyclic groups, chain alkyl groups and chain alkenyl groups in the explanation of (1), those which have no substituent or those which have a substituent other than a halogen atom are exemplified. R b12 The alkyl group is preferably a chain alkyl group which may have a substituent other than a halogen atom, or an aliphatic cyclic group which may have a substituent other than a halogen atom. The chain alkyl group preferably has 1 to 10 carbon atoms, and more preferably 3 to 10. The aliphatic cyclic group is preferably a group in which one or more hydrogen atoms have been removed from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like (which may have a substituent other than a halogen atom); or a group in which one or more hydrogen atoms have been removed from camphor, or the like. R b12 The hydrocarbon group may have a substituent other than a halogen atom, and the substituent may be R b11 Examples of the substituents include those similar to the substituents other than halogen atoms that may be contained in the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in the above formula. The phrase "may have a substituent other than a halogen atom" as used herein not only excludes cases where a substituent consists of only halogen atoms, but also excludes cases where a substituent contains at least one halogen atom (for example, when the substituent is a fluorinated alkyl group).

[0169] Preferred examples of the anion moiety of the component (I3-1) are shown below.

[0170] [ka]

[0171] Cation part In formula (I3-1), Mm+ is an m-valent organic cation. M m+ Suitable examples of the organic cation include the same cations as those represented by the general formulas (ca-1) to (ca-5) above, and among these, the cation represented by the general formula (ca-1) above is more preferred. 201 , R 202 , R 203 A sulfonium cation in which at least one of the above is an organic group having 16 or more carbon atoms (aryl group, heteroaryl group, alkyl group, or alkenyl group) which may have a substituent is particularly preferred because it improves resolution and roughness characteristics. The substituents that the organic group may have are the same as those described above, and include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an oxo group (═O), an aryl group, and groups represented by the above formulas (ca-r-1) to (ca-r-10). The number of carbon atoms in the organic group (aryl group, heteroaryl group, alkyl group, or alkenyl group) is preferably 16 to 25, more preferably 16 to 20, and particularly preferably 16 to 18. m+ Suitable organic cations include those represented by the above formulas (ca-1-25), (ca-1-26), (ca-1-28) to (ca-1-36), (ca-1-38), (ca-1-46), and (ca-1-47), and among these, the cation represented by the above formula (ca-1-29) is particularly preferred.

[0172] {Component (I3-2)} Anion section In formula (I3-2), R b11 is a cyclic group which may have a substituent other than a halogen atom, a chain alkyl group which may have a substituent other than a halogen atom, or a chain alkenyl group which may have a substituent other than a halogen atom, and R' 201Among the cyclic groups, chain alkyl groups and chain alkenyl groups in the explanation of (1), those which have no substituent or those which have a substituent other than a halogen atom are exemplified.

[0173] Among these, R b11 As the substituent, an aromatic hydrocarbon group which may have a substituent other than a halogen atom, an aliphatic cyclic group which may have a substituent other than a halogen atom, or a chain alkyl group which may have a substituent other than a halogen atom is preferred. Examples of the substituent which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a lactone-containing cyclic group, an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be connected via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the following general formulas (y-al-1) to (y-al-7). In the following general formulas (y-al-1) to (y-al-7), R in the above formula (I3-2) b11 The bond to V' in the following general formulas (y-al-1) to (y-al-7) is 101 is.

[0174] [ka] [In the formula, V' 101 V' is a single bond or an alkylene group having 1 to 5 carbon atoms. 102 is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms.]

[0175] V' 102 The divalent saturated hydrocarbon group in is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and even more preferably an alkylene group having 1 to 5 carbon atoms.

[0176] V' 101 and V' 102The alkylene group in may be a straight-chain alkylene group or a branched-chain alkylene group, and is preferably a straight-chain alkylene group. V' 101 and V' 102 Specific examples of the alkylene group in the formula (I) include a methylene group [-CH2-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; an ethylene group [-CH2CH2-]; -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2 -, etc.; a trimethylene group (n-propylene group) [-CH2CH2CH2-]; alkyl trimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-; a tetramethylene group [-CH2CH2CH2CH2-]; alkyl tetramethylene groups such as -CH(CH3)CH2CH2CH2- and -CH2CH(CH3)CH2CH2-; and a pentamethylene group [-CH2CH2CH2CH2CH2-]. Also, V' 101 or V' 102 In the above, some methylene groups in the alkylene group may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is represented by R' 201 A divalent group obtained by removing one hydrogen atom from a cyclic aliphatic hydrocarbon group (a monocyclic alicyclic hydrocarbon group or a polycyclic alicyclic hydrocarbon group) is preferred, and a cyclohexylene group, a 1,5-adamantylene group or a 2,6-adamantylene group is more preferred.

[0177] The aromatic hydrocarbon group is more preferably a phenyl group or a naphthyl group. The aliphatic cyclic group is more preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include straight-chain alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; and branched-chain alkyl groups such as a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

[0178] R b11 As the aryl group, a cyclic group which may have a substituent other than a halogen atom is preferred. Preferred examples of the anion moiety of the component (I3-2) are shown below.

[0179] [ka]

[0180] Cation part In formula (I3-2), M m+ is an m-valent organic cation, and M in the formula (I3-1) m+ is the same as:

[0181] Furthermore, from the viewpoints of increasing the elasticity of the resin film and facilitating the formation of a fine structure without residue, the component (I) is preferably a cationic polymerization initiator that generates an acid with a pKa (acid dissociation constant) of -5 or less upon exposure. By using a cationic polymerization initiator that generates an acid with a pKa of more preferably -6 or less, and even more preferably -8 or less, it becomes possible to obtain high sensitivity to exposure. The lower limit of the pKa of the acid generated by the component (I) is preferably -15 or more. By using a cationic polymerization initiator that generates an acid with such a suitable pKa, high sensitivity can be easily achieved. Here, "pKa (acid dissociation constant)" refers to a commonly used index indicating the acid strength of a substance of interest. In this specification, pKa is a value at a temperature of 25°C. The pKa value can be determined by measurement using known methods. Alternatively, a calculated value using known software such as "ACD / Labs" (trade name, manufactured by Advanced Chemistry Development) can also be used.

[0182] Specific examples of suitable components (I3) are listed below.

[0183] [ka]

[0184] As the component (I), one type may be used alone, or two or more types may be used in combination. In the photocurable composition of this embodiment, the component (I) preferably includes at least one selected from the group consisting of the component (I1), the component (I2), and the component (I3), and more preferably includes at least one selected from the group consisting of the component (I1) and the component (I2).

[0185] In the photocurable composition of this embodiment, the content of component (I) is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and even more preferably 0.2 to 1 part by mass, relative to 100 parts by mass of the total content of components (AC) and (A). When the content of component (I) is at least the lower limit of the above-mentioned preferred range, sufficient sensitivity is obtained, and the lithography properties of the resist pattern are further improved. In addition, the strength of the cured resin film is further increased. On the other hand, when the content is at most the upper limit of the above-mentioned preferred range, sensitivity is appropriately controlled, and a resist pattern with a good shape is more easily obtained.

[0186] <Optional ingredients> The photocurable composition of this embodiment may contain other components (optional components) as needed, in addition to the above-described components (AC), (A), and (I). If desired, the photocurable composition of the embodiment may contain miscible additives, such as a metal oxide (M), a sensitizer component, a solvent, an additional resin for improving the performance of the film, a dissolution inhibitor, a basic compound, a plasticizer, a stabilizer, a colorant, and an antihalation agent.

[0187] <Metal oxides (M)> In addition to the components (AC), (A), and (I), the photocurable composition of this embodiment may further contain a metal oxide (M) (hereinafter also referred to as "component (M)"), since this facilitates the formation of a cured film with increased strength. By including component (M), it is possible to form a pattern with a good shape and high resolution. Examples of the component (M) include oxides of metals such as silicon (metallic silicon), titanium, zirconium, hafnium, etc. Among these, oxides of silicon are preferred, and among these, it is particularly preferred to use silica. The component (M) is preferably in the form of particles, and the particulate component (M) preferably has a volume average particle diameter of 5 to 40 nm, more preferably 5 to 30 nm, and even more preferably 10 to 20 nm.

[0188] <Sensitizer ingredient> The photocurable composition of this embodiment may further contain a sensitizer component. The sensitizer component is not particularly limited as long as it can absorb energy from exposure and transfer that energy to another substance. Specific examples of the sensitizer component that can be used include benzophenone-based photosensitizers such as benzophenone and p,p'-tetramethyldiaminobenzophenone, carbazole-based photosensitizers, acetophenone-based photosensitizers, naphthalene-based photosensitizers such as 1,5-dihydroxynaphthalene, phenol-based photosensitizers, anthracene-based photosensitizers such as 9-ethoxyanthracene, and known photosensitizers such as biacetyl, eosin, rose bengal, pyrene, phenothiazine, and anthrone.

[0189] <Solvent> The photocurable composition of this embodiment may further contain a solvent (hereinafter sometimes referred to as "component (S)"). Examples of the component (S) include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having an ester bond such as 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; monoalkyl ethers or monoalkyl ethers of the above polyhydric alcohols or the above compounds having an ester bond such as monomethyl ether, monoethyl ether, monopropyl ether, and monobutyl ether; Examples of suitable organic solvents include derivatives of polyhydric alcohols such as compounds having an ether bond, such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) [among these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane; and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene; and dimethyl sulfoxide (DMSO).

[0190] The component (S) may be used alone or as a mixed solvent of two or more types.

[0191] When component (S) is included, the amount used is not particularly limited and is set appropriately depending on the coating film thickness and at a concentration that allows the photocurable composition to be applied to a substrate or the like without dripping. For example, the component (S) can be used so that the solid content concentration is 50% by mass or more, or the component (S) can be used so that the solid content concentration is 60% by mass or more. It is also possible to employ an embodiment in which the component (S) is substantially not contained (that is, an embodiment in which the solid content concentration is 100% by mass).

[0192] [Elastic modulus of cured film] Regarding the photocurable composition of this embodiment, when a cured film obtained by curing the photocurable composition was subjected to viscoelasticity measurement at a frequency of 1 Hz, the modulus of elasticity at a temperature of 80°C was 2.0 × 10 6 [Pa] or more 1.0×10 9 [Pa] or less.

[0193] The elastic modulus of the cured film is determined by measuring the tensile modulus at 80°C when the viscoelasticity is measured at a frequency of 1 Hz on a 50 μm thick photocurable film obtained by baking the above-mentioned photocurable composition in an oven at 60°C for 5 minutes, 70°C for 5 minutes, and 80°C for 10 minutes in that order, exposing the film to g-, h-, and i-rays at a dose sufficient to form a 100 μm pattern for each composition, and then baking the cured film after exposure at 90°C for 5 minutes. The preferred heating condition is 1 to 10°C / min.

[0194] For the photocurable composition of this embodiment, the elastic modulus of the cured film obtained by curing the photocurable composition is 2.0 × 10 6 [Pa] or more 1.0×10 9 [Pa] or less, preferably 2.0 × 10 6 [Pa] or more 8.0×10 8 [Pa] or less, and more preferably 2.5 × 10 6 [Pa] or more 7.5×10 8 [Pa] or less. When the modulus of elasticity of the cured film is equal to or greater than the lower limit of the above range, the cured film has sufficient strength and is less likely to deform the pattern structure, thereby improving the structure retention.On the other hand, when the modulus of elasticity is equal to or less than the upper limit of the above range, the adhesion between the cured film and the object is likely to be improved.

[0195] The elastic modulus of the cured film described above can be adjusted to 2.0×10 or more by appropriately adjusting, for example, the copolymerization composition, glass transition temperature, and weight average molecular weight of the acrylic resin (AC) blended in the photocurable composition; the type of epoxy group-containing compound (A); and the mixing ratio of the acrylic resin (AC) and the epoxy group-containing compound (A). 6 [Pa] or more 1.0×10 9 It can be controlled below [Pa]. In particular, it is effective to appropriately adjust the elastic modulus of the cured film by adjusting the copolymer composition and glass transition point of the acrylic resin (AC) and the mixing ratio of the acrylic resin (AC) to the epoxy group-containing compound (A).

[0196] The photocurable composition of this embodiment has a viscosity at 23° C. of, for example, 10 to 5000 mPa·s, or may be 30 to 3000 mPa·s, or may be 50 to 2000 mPa·s.

[0197] The photocurable composition of the present embodiment described above contains an acrylic resin (AC), an epoxy group-containing compound (A), and a cationic polymerization initiator (I). The (AC) component has a glass transition point of 0°C or less. This improves the properties of the cured film, enhancing its adhesiveness to the target object. Additionally, the cured film obtained by curing the photocurable composition has a modulus of elasticity of 2.0 x 10 at a temperature of 80°C when viscoelasticity is measured at a frequency of 1 Hz. 6 [Pa] or more 1.0×10 9 [Pa] or less. As a result, the cured film formed by the reaction of component (AC), component (A), and component (I) has sufficient strength, is less likely to deform the pattern structure, and maintains adhesion strength to the object to be bonded. Furthermore, in pattern formation, high-resolution patterns can be formed with good shapes, and lithography properties can be improved. Therefore, the photocurable composition of this embodiment has good pattern formability and high reliability, and when formed into a cured film, it can enhance adhesion to an object.

[0198] Furthermore, the photocurable composition of this embodiment improves the structural retention of the pattern against external forces when bonding to an object. Furthermore, electronic components to which the photocurable composition of this embodiment is applied have improved durability in the usage environment, enabling stable continuous use and improving reliability. The photocurable composition of this embodiment is useful as a photocurable adhesive material used in the production of electronic components (e.g., MEMS, bio-related components, etc.) that require various properties such as pattern formability, reliability, and adhesiveness.

[0199] (Pattern formation method) The pattern formation method of the present embodiment includes a step of forming a photocurable film on a support using the photocurable composition of the above-described embodiment (hereinafter referred to as a "film formation step"), a step of exposing the photocurable film to light (hereinafter referred to as an "exposure step"), and a step of developing the exposed photocurable film with a developer containing an organic solvent to form a negative pattern (hereinafter referred to as a "development step"). The pattern forming method of this embodiment can be carried out, for example, as follows.

[0200] [Film formation process] First, the photocurable composition of the above-described embodiment is applied onto a support by a known method such as spin coating, roll coating, or screen printing, and then baked (post-apply bake (PAB)) for 2 to 60 minutes at a temperature of 50 to 150°C, for example, to form a photocurable film.

[0201] The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and those on which a predetermined wiring pattern is formed, etc. More specifically, metal substrates such as silicon, silicon nitride, titanium, tantalum, lithium tantalate (LiTaO), niobium, lithium niobate (LiNbO), palladium, titanium tungsten, copper, chromium, iron, and aluminum, as well as glass substrates, etc. The wiring pattern may be made of a material such as copper, aluminum, nickel, or gold.

[0202] The thickness of the photocurable film formed from the photocurable composition is not particularly limited, but is preferably about 10 to 50 μm.

[0203] [Exposure process] Next, the formed photocurable film is subjected to selective exposure using a known exposure device, such as exposure through a mask (mask pattern) on which a predetermined pattern is formed, or by drawing by direct irradiation with an electron beam without using a mask pattern. After the selective exposure, if necessary, baking (post-exposure bake (PEB)) treatment is carried out at a temperature of 80 to 150° C. for 40 to 1200 seconds, preferably 40 to 1000 seconds, more preferably 60 to 900 seconds.

[0204] The wavelength used for exposure is not particularly limited, and radiation such as ultraviolet light having a wavelength of 300 to 500 nm, g-rays, h-rays, i-rays (wavelength 365 nm), or visible light can be selectively irradiated (exposed). As the radiation source, a low-pressure mercury lamp, a high-pressure mercury lamp, an extra-high-pressure mercury lamp, a metal halide lamp, an argon gas laser, etc. can be used. Here, radiation refers to ultraviolet light, visible light, far ultraviolet light, X-rays, electron beams, etc. The radiation dose varies depending on the type and amount of each component in the composition, the thickness of the coating film, etc. For example, when an ultra-high pressure mercury lamp is used, it is 100 to 2000 mJ / cm. 2 is.

[0205] The exposure method for the photocurable film may be a normal exposure (dry exposure) carried out in air or an inert gas such as nitrogen, or may be liquid immersion lithography.

[0206] The photocurable film after the exposure step has high transparency, and for example, the haze value when irradiated with i-line (wavelength 365 nm) is preferably 3% or less, more preferably 1.0 to 2.7%. The haze value of the photocurable film after such an exposure step is measured using a method in accordance with JIS K 7136 (2000).

[0207] [Development process] Next, the exposed photocurable film is developed with a developer containing an organic solvent (organic developer). After development, a rinse treatment is preferably performed. If necessary, a bake treatment (post-bake) may be performed.

[0208] The organic solvent contained in the organic developer may be any solvent capable of dissolving the components (A) and (AC) before exposure, and may be appropriately selected from known organic solvents. Specific examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, as well as hydrocarbon solvents.

[0209] Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone (2-heptanone), etc. Among these, methyl amyl ketone (2-heptanone) is preferred as the ketone solvent.

[0210] Examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate (PGMEA), ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, Pyrene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, milk Examples of the alkyl esters include ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and propyl 3-methoxypropionate.Among these, butyl acetate or PGMEA is preferred as the ester solvent.

[0211] Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0212] The organic developer may contain known additives as needed. Examples of such additives include surfactants. The surfactants are not particularly limited, but may include, for example, ionic or nonionic fluorine-based and / or silicon-based surfactants. The surfactant is preferably a nonionic surfactant, and more preferably a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant. When a surfactant is added, the amount added is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the organic developer.

[0213] The development process can be carried out by a known development method, such as a method of immersing the support in a developer for a certain period of time (dip method), a method of piling up the developer on the surface of the support by surface tension and leaving it standing for a certain period of time (puddle method), a method of spraying the developer onto the surface of the support (spray method), or a method of continuously applying the developer while scanning a developer application nozzle at a constant speed onto a support rotating at a constant speed (dynamic dispense method).

[0214] The rinse treatment (cleaning treatment) using a rinse solution can be carried out by a known rinse method, such as a method in which the rinse solution is continuously applied onto a support rotating at a constant speed (spin coating method), a method in which the support is immersed in the rinse solution for a certain period of time (dipping method), or a method in which the rinse solution is sprayed onto the surface of the support (spray method). The rinsing treatment is preferably carried out using a rinsing liquid containing an organic solvent.

[0215] A pattern can be formed by the above-described film forming step, exposure step, and development step.

[0216] In the pattern formation method of the above-described embodiment, the photocurable composition of the above-described embodiment is used, and therefore, in the pattern formation, a resin pattern with high resolution and good shape is formed, and the lithography properties are excellent.

[0217] (cured film) The cured film of this embodiment is obtained by curing the photocurable composition of the above-described embodiment. In the cured film of this embodiment, the elastic modulus at a temperature of 80°C when viscoelasticity was measured at a frequency of 1 Hz was 2.0 × 10 6 [Pa] or more 1.0×10 9 [Pa] or less, preferably 2.0 × 10 6 [Pa] or more 8.0×10 8 [Pa] or less, more preferably 2.5 × 10 6 [Pa] or more 7.5×10 8 [Pa] or less. The cured film of this embodiment has improved adhesion to the object. In addition, the cured film of this embodiment maintains adhesion strength with the object to be bonded in a TCT test, thereby improving reliability. Furthermore, the cured film of this embodiment is less likely to cause deformation of the pattern structure and has structure retention.

[0218] (Method of manufacturing cured film) The method for producing a cured film of this embodiment includes a step (i) of forming a photocurable film on a support using the photocurable composition of the above-described embodiment, and a step (ii) of curing the photocurable film to obtain a cured film. The operation of step (i) can be carried out in the same manner as in the above-mentioned [film formation step]. The baking treatment can be carried out, for example, at a temperature of 80 to 150° C. for 40 to 600 seconds. The curing treatment in step (ii) can be carried out, for example, at a temperature of 100 to 250° C. for 0.5 to 2 hours.

[0219] The method for producing a cured film according to the embodiment may include other steps in addition to steps (i) and (ii). For example, the above-described "exposure step" may be included between steps (i) and (ii). The photocurable film formed in step (i) may be selectively exposed to light, and the photocurable film (pre-cured film) may be cured after being subjected to post-exposure bake (PEB) treatment as needed, to obtain a cured film. According to the method for producing a cured film of the above-described embodiment, since the photocurable composition of the above-described embodiment is used, it is possible to produce a cured film having improved adhesion to the target object, such as an electronic component such as a silicon chip. Furthermore, according to this method for producing a cured film, it is possible to produce a highly reliable cured film that is less likely to cause deformation of the pattern structure and maintains adhesion strength with the target object. [Example]

[0220] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0221] <Production of acrylic resin> The "monomers from which the structural units are derived" shown in Table 1 were used to carry out known radical polymerization to obtain acrylic resins (AC)-1 to (AC)-9 and acrylic resins (AC)-11 to (AC)-14, respectively.

[0222] Table 1 shows the proportions of each structural unit that constitutes the acrylic resin, as well as the properties of the acrylic resin, such as the glass transition temperature Tg (°C), the content (mass%) of the structural unit (ac1) in the acrylic resin, and the weight average molecular weight Mw of the acrylic resin.

[0223] The glass transition temperature of the acrylic resin was calculated using the following formula. 1 / (Tg+273) ={W1 / (Tg1+273)+W2 / (Tg2+273)+···} / 100 Tg: Glass transition temperature of the acrylic copolymer (℃) Tg1: Glass transition temperature (°C) of a homopolymer consisting of a repeating structure of structural unit (1) derived from monomer (1) Tg2: Glass transition temperature (°C) of a homopolymer consisting of a repeating structure of structural unit (2) derived from monomer (2) W1: Proportion (mass%) of structural unit (1) constituting acrylic resin W2: Proportion (mass%) of structural unit (2) constituting acrylic resin W1+W2+=100

[0224] The glass transition temperatures of homopolymers were determined from the values ​​disclosed on the KTR (Kaji Test Research) website (www.kaji-tr.com), the Polymer Materials Handbook (edited by the Society of Polymer Science, Corona Publishing, first edition, published February 20, 1973), the Acrylic Products Catalog of Kyoeisha Chemical Co., Ltd., and the Polymer Data Handbook Basics (edited by the Society of Polymer Science, Baifukan Publishing, published January 30, 1986).

[0225] For example, the glass transition temperature Tg (°C) of the acrylic resin (AC)-2 was calculated as follows. The acrylic resin (AC)-2 is a copolymer of structural units derived from 2-methoxyethyl acrylate and structural units derived from n-butyl acrylate. When the monomer (1) is 2-methoxyethyl acrylate, the glass transition point of a homopolymer consisting of a repeating structure of the structural unit (1) is −50° C., and the proportion of the structural unit (1) is 73 mass %. When the monomer (2) is n-butyl acrylate, the glass transition point of a homopolymer consisting of a repeating structure of the structural unit (2) is −56° C., and the proportion of the structural unit (2) is 27% by mass. The glass transition temperature Tg (°C) of the acrylic resin (AC)-2 is calculated by the following formula. 1 / (Tg+273) ={73 / (-50+273)+27 / (-56+273)} / 100 Tg ≒ -52℃

[0226] For each of the obtained acrylic resins, the copolymerization composition ratio of the acrylic resin (the proportion (% by mass) of each structural unit constituting the acrylic resin) was: 13 The carbon content was determined by C-NMR. The weight average molecular weight (Mw) of the acrylic resin was determined by gel permeation chromatography (GPC) measurement and expressed as a value converted into standard polystyrene.

[0227] [Table 1]

[0228] <Preparation of Photocurable Composition> (Examples 1 to 13, Comparative Examples 1 to 7) The components shown in Tables 2 and 3 were mixed and dissolved in methyl ethyl ketone, and the mixture was filtered using a PTFE filter (pore size 1 μm, manufactured by PALL Corporation) to prepare the photocurable compositions of each example (solutions with a solids concentration of 73% by mass and a viscosity of 1500 mPa s at 23°C).

[0229] [Table 2]

[0230] [Table 3]

[0231] In Tables 2 and 3, the abbreviations have the following meanings: The values ​​in brackets [ ] are the blending amounts of each component (parts by mass; solid content equivalent).

[0232] (AC)-1 to (AC)-9: Acrylic resins (AC)-1 to (AC)-9 shown in Table 1 (AC)-11 to (AC)-14: Acrylic resins (AC)-11 to (AC)-14 shown in Table 1

[0233] (A1)-1: Solid novolac epoxy resin represented by the following chemical formula (anv0-1). Product name: "jER-157S70", manufactured by Mitsubishi Chemical Corporation. Softening point: 70°C, glass transition point: 210°C, epoxy equivalent: 200-220g / eq.

[0234] [ka]

[0235] (A1)-2: Solid cresol novolac epoxy resin obtained by glycidyl etherifying ortho-cresol novolac. Product name: YDCN-704, manufactured by Nippon Steel & Sumitomo Metal Corporation. Softening point: 87-97°C, glass transition point: 255°C, epoxy equivalent: 202-214g / eq.

[0236] (A2)-1: Solid bisphenol-type epoxy resin represented by the following chemical formula (abp1-0). Product name: "jER-1002", manufactured by Mitsubishi Chemical Corporation. Softening point: 78°C, weight-average molecular weight: 1200, epoxy equivalent: 600-700 g / eq. (A2)-2: Solid bisphenol-type epoxy resin represented by the following chemical formula (abp1-0). Product name: "jER-1003", manufactured by Mitsubishi Chemical Corporation. Softening point: 89°C, weight-average molecular weight: 1300, epoxy equivalent: 670-770 g / eq.

[0237] [ka]

[0238] (I)-1: A cationic polymerization initiator represented by the following chemical formula (I2-1-2).

[0239] [ka]

[0240] <Evaluation> The modulus of elasticity at 80° C. of each photocurable composition was measured by the method described below. Furthermore, the photocurable compositions of each example were evaluated for adhesion, reliability, lithography properties (lithographic properties), and structural retention by the following evaluation methods. The results are shown in Tables 4 and 5.

[0241] [Measurement of elastic modulus at 80℃] The photocurable composition of each example was applied to a PET film (with release treatment) as a substrate using an applicator, and then dried by baking in an oven at 60°C for 5 minutes, 70°C for 5 minutes, and 80°C for 10 minutes, in that order, to form a photocurable film with a thickness of 50 μm. Next, the entire surface of the photocurable film was exposed to g-, h-, and i-rays at a dose sufficient to form a 100 μm pattern of each composition, followed by post-exposure heating on a hot plate at 90° C. for 5 minutes to obtain the desired cured film.

[0242] The elastic modulus of the resulting cured film was measured as follows. The cured film was peeled off from the PET film and cut into a piece measuring 5 mm x 20 mm to prepare a sample for measuring elastic modulus. The elastic modulus of the cured film was measured by carrying out viscoelasticity measurement on this sample using the following evaluation device and measurement conditions. Measurement equipment: Dynamic viscoelasticity device (UBM) Measurement conditions: tension mode, frequency 1.0Hz, chuck distance 10mm, temperature 80℃, heating rate 5℃ / min The higher the modulus of elasticity, the stronger the cured film.

[0243] [Adhesion evaluation] Preparation of measurement substrate: Each photocurable composition of each example was applied to a silicon substrate by spin coating, and then baked in an oven at 60°C for 5 minutes, 70°C for 5 minutes, and 80°C for 10 minutes, in that order, to form a cured film with a thickness of 20 μm. Next, the cured film formed on the silicon substrate was bonded to a 5 mm square silicon chip, and then the cured film and the 5 mm square silicon chip were thermocompressed together using a chip bonder (TRESKY Corp., die bonder) at 150°C under a load of 3500 g for 60 seconds to prepare a measurement substrate.

[0244] ·Shear strength measurement The measurement substrate was fixed using a bond tester (XYZTEC, Condor Sigma) at room temperature (23°C), and a shear force was applied to the 5 mm square silicon chip portion. The force required to peel the 5 mm square silicon chip from the cured film (shear strength, N / mm 2 ) was measured.

[0245] - Evaluation of bonding condition The shear strength between the cured film and a 5 mm square silicon chip was used as an index, and the bonding state was observed to evaluate the adhesiveness according to the following evaluation criteria. Evaluation criteria 〇: Shear strength is 5N / mm 2 As a result, the two were firmly bonded together. ×: Shear strength is 5N / mm 2 The adhesive strength was weak, and the 5 mm square silicon chip was easily peeled off from the cured film.

[0246] [Reliability assessment] The reliability was evaluated by the thermal cycle test (TCT) shown below. Preparation of measurement substrates for TCT In the preparation of the measurement substrate in the above-mentioned [Evaluation of Adhesion], except that the 5 mm square silicon chip was replaced with a 5 mm square glass, the cured film was thermocompressed to the 5 mm square glass to prepare a measurement substrate for use in TCT. TCT The thermal cycle test was carried out under the following test conditions. Temperature and time cycle: -55℃~125℃ (cycles every 30 minutes) Test time: 1000 hours Evaluation criteria The condition of the measurement substrate after the thermal cycle test was observed, and reliability was evaluated by rating it as "Good" if there was no peeling between the cured film and the 5 mm square glass, and rating it as "Poor" if there was peeling between the cured film and the 5 mm square glass. In the table, "ND" means that a pattern could not be formed before curing and TCT could not be performed.

[0247] [Evaluation of lithography characteristics (litho characteristics)] Using the photocurable composition of each example, a pattern was formed. Film formation process: Each photocurable composition was applied to a silicon substrate by spin coating, and then baked in an oven at 60°C for 5 minutes, 70°C for 5 minutes, and 80°C for 10 minutes, to form a photocurable film with a thickness of 20 μm.

[0248] Exposure process: Next, the photocurable film was irradiated with g-, h-, and i-rays using an exposure machine (Prisma ghi). Next, the exposed photocurable film was subjected to post-exposure heating on a hot plate at 90° C. for 5 minutes.

[0249] Development process: Next, the photocurable film after post-exposure baking was subjected to puddle development at room temperature (23° C.) for 15 minutes using propylene glycol monomethyl ether acetate (PGMEA) as a developer.

[0250] Using the above-described film formation process, exposure process, and development process, an attempt was made to form a line and space pattern (hereinafter referred to as "L / S pattern") with a line width of 100 μm and a space width of 300 μm. Then, the state of the L / S pattern was observed according to the following evaluation criteria to evaluate the lithography characteristics. Evaluation criteria ◯: A line with a width of 100 μm was formed with a good shape. ×: The shape of the L / S pattern was poor.

[0251] [Evaluation of structural retention] A line pattern was formed on a silicon substrate in the same manner as in the pattern formation method described above in [Evaluation of lithography characteristics (litho characteristics)]. The coating was then cured by heating at 200° C. for 1 hour in a nitrogen atmosphere to obtain a cured film with a line width of 700 μm. Next, the cured film with a line width of 700 μm formed on the silicon substrate was bonded to a 5 mm square glass, and then thermocompression bonded using a chip bonder (TRESKY Corp., die bonder) at 100°C with a bonding load of 3000 g for 60 minutes. The state of the cured film after 60 minutes of thermocompression bonding was observed to evaluate the structural retention according to the following evaluation criteria. Evaluation criteria ◯: The change in line width was less than 20 μm. ×: The amount of change in line width was 20 μm or more. The smaller the change in line width, the smaller the deformation of the pattern structure, meaning that the structure is more easily retained.

[0252] [Table 4]

[0253] [Table 5]

[0254] From the results in Tables 4 and 5, it can be seen that the photocurable compositions of Examples 1 to 13 to which the present invention is applied can enhance adhesion to the target object when formed into a cured film, are durable against temperature changes and highly reliable, and can form patterns with good shapes in pattern formation, demonstrating excellent lithography properties. In addition, it can be confirmed that the photocurable compositions of Examples 1 to 13 have high structure retention. On the other hand, the photocurable compositions of Comparative Examples 1 to 7, which are outside the scope of the present invention, were evaluated as being poor in at least one of adhesion, reliability, and lithography properties.

[0255] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A photocurable composition containing an acrylic resin (AC), an epoxy group-containing compound (A) (excluding those corresponding to the acrylic resin (AC)), and a cationic polymerization initiator (I), The acrylic resin (AC) has a glass transition point of 0°C or lower and includes a structural unit (ac1) formed by cleavage of the ethylenic double bond of an epoxy group-containing acrylic monomer, the epoxy group-containing compound (A) contains at least one epoxy resin selected from the group consisting of bisphenol-type epoxy resins and novolac-type epoxy resins, When the viscoelasticity of the cured film obtained by curing the photocurable composition was measured at a frequency of 1 Hz, the elastic modulus at a temperature of 80°C was 2.0 × 10 ６ [Pa] or more 1.0×10 ９ The photocurable composition has a viscosity of [Pa] or less.

2. 2. The photocurable composition according to claim 1, wherein a mixing ratio of the acrylic resin (AC) to the epoxy group-containing compound (A) is, in mass ratio, epoxy group-containing compound (A) / acrylic resin (AC)=40 / 60 to 95 / 5.

3. 3. The photocurable composition according to claim 1, wherein the epoxy group-containing compound (A) comprises at least one epoxy resin selected from the group consisting of epoxy resins represented by the following general formula (abp1), epoxy resins represented by the following general formula (anv0), and resins having a structural unit represented by the following general formula (anv1): 【Chemistry 1】 [In the formula, R ＥＰ is an epoxy group-containing group. ＥＰ may be the same or different. ａ３１ and R ａ３２ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms. ３１ is an integer from 1 to 50. 【Chemistry 2】 [In the formula, R ｐ１ and R ｐ２ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ｐ１ may be the same or different. ｐ２ may be the same or different. １ is an integer from 1 to 5. ＥＰ is an epoxy group-containing group. ＥＰ may be the same or different from each other. 【Transformation 3】 [In the formula, R ＥＰ is an epoxy group-containing group. ａ２２ and R ａ２３ are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom.

4. The photocurable composition according to claim 3 , wherein the epoxy group-containing compound (A) comprises an epoxy resin represented by the general formula (abp1).

5. 3. The photocurable composition according to claim 1, wherein a content of the cationic polymerization initiator (I) is 0.05 to 5 parts by mass per 100 parts by mass of a total content of the acrylic resin (AC) and the epoxy group-containing compound (A).

6. forming a photocurable film on a support using the photocurable composition according to claim 1 or 2; exposing the photocurable film to light; developing the exposed photocurable film with a developer containing an organic solvent to form a negative pattern; A pattern forming method comprising the steps of:

7. A cured film obtained by curing the photocurable composition according to claim 1 or 2.

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