Raw material resin and acid-degradable resin

Abstract

To provide a raw material resin, which is a novolac resin suitable for use as the raw material resin for an acid-degradable resin, exhibiting superior heat resistance and superior dissolution rates, and an acid-degradable resin comprising the raw material resin.SOLUTION: A raw material resin comprises units connected to each other through methylene groups, where the units comprise at least second unit (2) from among a first unit (1) and the second unit (2).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a raw material resin and an acid-decomposable resin. More specifically, the present invention relates to a raw material resin suitable as a raw material for an acid-decomposable resin, and an acid-decomposable resin using the raw material resin. [Background technology]

[0002] In the manufacturing process of semiconductor parts and electronic parts, a photomask is required for each patterning. Photomasks are processed into photomasks having the desired pattern by exposing and developing a resin film (photosensitive resin film) obtained by applying and drying a photosensitive resin composition containing an acid-decomposable resin, a photoacid generator, a solvent, etc. For example, Patent Document 1 listed below discloses a photosensitive resin composition containing an acid-decomposable resin formed by introducing an acid-decomposable protecting group into a novolak resin, an acid generator, and a solvent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-204036 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, the acid-decomposable resin, which is an important component of the photosensitive resin composition, is generally formed by introducing a protecting group exhibiting acid decomposition into a raw material resin. Therefore, the properties of the obtained acid-decomposable resin depend on the properties of the raw material resin. In this respect, when a conventional novolac resin is used as the raw material resin, there is room for improvement in terms of the balance between dissolution rate and heat resistance. That is, the conventional novolac resin has a problem that the dissolution rate decreases when the heat resistance is improved.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a novolac resin used as a raw material resin for an acid-decomposable resin, which raw material resin can achieve both excellent heat resistance and an excellent dissolution rate, and an acid-decomposable resin using this raw material resin. [Means for solving the problem]

[0006] That is, the present invention includes the following inventions. [1] A raw material resin that becomes an acid-decomposable resin by introducing an acid-decomposable group, The raw material resin has units connected to each other via methylene groups, The unit includes a first unit represented by the following formula (1) and at least the second unit represented by the following formula (2): [ka] R in the above formula (1) 11 R in the formula (2) 21 R in the formula (2) 31 is at least partially a monovalent substituent, The raw material resin is characterized in that the monovalent substituent is selected from the group consisting of alkyl groups and aryl groups having 1 to 5 carbon atoms. [2] The raw material resin according to the above [1], wherein, when the number of the first units is n and the number of the second units is m, 0.05≦m / (n+m)≦1 is satisfied. [3] The raw material resin according to [1] or [2] above, having an average weight molecular weight of 2,500 or more. [4] The raw material resin according to any one of [1] to [3] above, having a glass transition temperature of 85°C or higher. [5] An acid-decomposable resin, characterized in that at least a portion of the hydrogen atoms constituting the hydroxyl groups constituting the raw material resin according to any one of [1] to [4] above is substituted with a monovalent acid-decomposable group. [6] The acid-decomposable resin according to the above [5], wherein the modification rate with the acid-decomposable group is 10% or more. Effect of the Invention

[0007] The raw material resin of the present invention can achieve both excellent heat resistance and excellent dissolution rate. According to the acid-decomposable resin of the present invention, it is possible to design a photosensitive resin composition capable of forming a photosensitive resin film having excellent heat resistance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will be described below based on specific embodiments. However, the present invention is not limited to these embodiments. These embodiments are merely examples shown for the sake of convenience, and the present invention is not limited to these in any sense. The present invention can be modified in various ways depending on the purpose and application. In addition, all publications, patents, and patent applications cited in this specification are incorporated herein by reference as they are. In addition, in this specification, the description "XX-YY" means "XX or more and YY or less." Furthermore, in the compounds exemplified in this specification, a CAS Registry Number may be written in addition to a part of a compound name that has multiple notations, but since the CAS Registry Number differs depending on the isomeric form, etc., this is only an example of the compound name written in addition, and does not correspond one-to-one to the compound name and the CAS Registry Number.

[0009] [1] Raw resin The raw material resin has units connected to each other via methylene groups, The unit includes a first unit represented by the following formula (1) and at least the second unit represented by the following formula (2): [ka] R in formula (1) 11 , R in Eq. (2) 21 , R in Eq. (2) 31 At least a part of R is a monovalent substituent, and the monovalent substituent is selected from the group consisting of an alkyl group and an aryl group having 1 to 5 carbon atoms (i.e., R 11 , R 21and R 31 are each independently at least a portion of which is a monovalent substituent.

[0010] The raw material resin may be obtained by any method, but may be obtained, for example, as a copolymer (novolac resin) in which a phenolic compound (a compound having an aromatic ring and a phenolic hydroxyl group) and an aldehyde compound are used as monomers. That is, the first unit and the second unit are structural units derived from a phenolic compound, and the methylene group is a structural unit derived from an aldehyde compound. A phenolic compound is a compound having a phenolic hydroxy group. That is, the phenolic hydroxy group is a hydroxy group bonded to a carbon atom that constitutes an aromatic ring and has no substituent other than the hydroxy group. An aldehyde compound is a compound having an aldehyde group (-CHO).

[0011] The first unit (the unit represented by the above formula (1)) is a phenol or a monovalent substituent (R 11 The unit is based on a phenol derivative having a monovalent substituent (R 11 ) include alkyl groups and aryl groups having 1 to 5 carbon atoms. Therefore, R in Equation (1) 11 Examples of the R include H (hydrogen atom), an alkyl group having 1 to 5 carbon atoms, and an aryl group. These may be used alone or in combination of two or more. That is, since there are a plurality of first units constituting the raw material resin, there are a plurality of R 11 There are multiple R 11 may be the same or different from each other.

[0012] Monovalent substituent (R 11Among these, examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group (n-propyl group, isopropyl group), a butyl group (n-butyl group, isobutyl group, tert-butyl group), a pentyl group (n-pentyl group, isopentyl group, tert-pentyl group, etc.), etc. These may be used alone or in combination of two or more kinds.

[0013] Monovalent substituent (R 11 Examples of the aryl group among these include a phenyl group, a tolyl group (p-tolyl group, o-tolyl group, m-tolyl group), and a xylyl group (2,3-xylyl group, 2,4-xylyl group, 2,5-xylyl group, 2,6-xylyl group). These may be used alone or in combination of two or more. The number of carbon atoms constituting the aryl group is not limited, but may be 6 to 12.

[0014] That is, examples of the compound (monomer) that serves as the base of the first unit include phenol, 2-alkylphenol, 2-arylphenol, etc. These may be used alone or in combination of two or more kinds. Among the above, examples of 2-alkylphenols include 2-methylphenol (o-cresol), 2-ethylphenol, 2-propylphenol, 2-butylphenol, and 2-pentylphenol. These may be used alone or in combination of two or more. Examples of 2-arylphenols include 2-phenylphenol [also known as 1,1'-biphenyl-2-ol], 2-(2-methylphenyl)phenol [also known as 1,1'-biphenyl-2-ol, 2'-methyl], and 1,1'-biphenyl-2-ol, 2',4'-dimethyl. These may be used alone or in combination of two or more. Among these, from the viewpoint of obtaining solubility in a solvent, 2-alkylphenols are preferred, and o-cresol is more preferred. On the other hand, from the viewpoint of better heat resistance, 2-phenylphenol is preferred.

[0015] The second unit (the unit represented by the above formula (2)) is a unit based on dihydroxybiphenyl or a derivative thereof. That is, examples of the compound (monomer) that is the base of the second unit include dihydroxybiphenyl and its derivatives. These may be used alone or in combination of two or more.

[0016] Among the above, the dihydroxybiphenyls include 2,2'-dihydroxybiphenyl, 2,3'-dihydroxybiphenyl, 2,4'-dihydroxybiphenyl, 2,5'-dihydroxybiphenyl, 2,6'-dihydroxybiphenyl, 3,2'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 3,5'-dihydroxybiphenyl, 3,6'-dihydroxybiphenyl, 4,2'-dihydroxybiphenyl, 4,3'-dihydroxybiphenyl, 4 , 4'-dihydroxybiphenyl, 4,5'-dihydroxybiphenyl, 4,6'-dihydroxybiphenyl, 5,2'-dihydroxybiphenyl, 5,3'-dihydroxybiphenyl, 5,4'-dihydroxybiphenyl, 5,5'-dihydroxybiphenyl, 5,6'-dihydroxybiphenyl, 6,2'-dihydroxybiphenyl, 6,3'-dihydroxybiphenyl, 6,4'-dihydroxybiphenyl, 6,5'-dihydroxybiphenyl, 6,6'-dihydroxybiphenyl, etc. These may be used alone or in combination of two or more.

[0017] As a derivative of dihydroxybiphenyl, a hydroxyl group and a monovalent substituent (R of the second unit) are attached to two adjacent carbon atoms of one benzene ring forming a biphenyl structure. 21 or R 31 and a hydroxy group on any of the carbon atoms at positions 2 to 5 of the other benzene ring forming the biphenyl structure (a compound represented by the following formula (3) or (4)). As a derivative of dihydroxybiphenyl, there is a compound having a hydroxy group and a monovalent substituent (R 21and the other benzene ring that constitutes the biphenyl structure has a hydroxy group and a monovalent substituent (R 31 (a compound represented by the following formula (5)), and the like.

[0018] [ka]

[0019] Monovalent substituent (R 21 or R 31 ) include alkyl groups and aryl groups having 1 to 5 carbon atoms. These may be used alone or in combination of two or more kinds. In other words, since there are multiple second units that constitute the raw resin, there are multiple R 21 and R 31 There are multiple R 21 may be the same or different. Similarly, these multiple R 31 may be the same or different from each other.

[0020] Monovalent substituent (R 21 or R 31 Among these, examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group (n-propyl group, isopropyl group), a butyl group (n-butyl group, isobutyl group, tert-butyl group), a pentyl group (n-pentyl group, isopentyl group, tert-pentyl group, etc.), etc. These may be used alone or in combination of two or more kinds.

[0021] Monovalent substituent (R 21 or R 31 Examples of the aryl group among these include a phenyl group, a tolyl group (p-tolyl group, o-tolyl group, m-tolyl group), and a xylyl group (2,3-xylyl group, 2,4-xylyl group, 2,5-xylyl group, 2,6-xylyl group). These may be used alone or in combination of two or more kinds.

[0022] Therefore, examples of the derivatives of dihydroxybiphenyl represented by the above formula (3) or (4) include 4,2'-dihydroxy-2-alkylbiphenyl, 4,2'-dihydroxy-3-alkylbiphenyl, 4,2'-dihydroxy-5-alkylbiphenyl, 4,2'-dihydroxy-6-alkylbiphenyl, 4,3'-dihydroxy-2-alkylbiphenyl, 4,3'-dihydroxy-3-alkylbiphenyl, 4,3'-dihydroxy-5-alkylbiphenyl, 4,3'-dihydroxy-6-alkylbiphenyl, 4,4' 4,4'-dihydroxy-3-alkylbiphenyl, 4,4'-dihydroxy-2-alkylbiphenyl, 4,5'-dihydroxy-2-alkylbiphenyl, 4,5'-dihydroxy-3-alkylbiphenyl, 4,5'-dihydroxy-5-alkylbiphenyl, 4,5'-dihydroxy-6-alkylbiphenyl, 4,6'-dihydroxy-2-alkylbiphenyl, 4,6'-dihydroxy-3-alkylbiphenyl, 4,6'-dihydroxy-5-alkylbiphenyl, 4,6'-dihydroxy-6-alkylbiphenyl, etc. These may be used alone or in combination of two or more.

[0023] Furthermore, examples of the derivatives of dihydroxybiphenyl represented by the above formula (5) include 3,2'-dihydroxy-2,3'-dialkylbiphenyl, 3,2'-dihydroxy-4,3'-dialkylbiphenyl, 3,3'-dihydroxy-2,2'-dialkylbiphenyl, 3,3'-dihydroxy-4,2'-dialkylbiphenyl, 4,2'-dihydroxy-2,3'-dialkylbiphenyl, 4,2'-dihydroxy-3,3'-dialkylbiphenyl, 4,2'-dihydroxy-3,4'-dialkylbiphenyl, 4,2'-dihydroxy-5,5'-dialkylbiphenyl, 4,2'-dihydroxy-6,6'-dialkylbiphenyl, 4,3'-dihydroxy-2,2'-dialkylbiphenyl, 4,3'-dihydroxy-3,4'-dialkylbiphenyl, and 4,3'-dihydroxy-5,5'-dialkylbiphenyl. , 4,3'-dihydroxy-6,6'-dialkylbiphenyl, 4,4'-dihydroxy-2,2'-dialkylbiphenyl, 4,4'-dihydroxy-3,3'-dialkylbiphenyl, 4,4'-dihydroxy-2,5'-dialkylbiphenyl, 4,4'-dihydroxy-2,6'-dialkylbiphenyl, 4,5'-dihydroxy-2,2'-dialkylbiphenyl, 4,5'-dihydroxy-3,3'-dialkylbiphenyl, 4,5'-dihydroxy-5,4'-dialkylbiphenyl, 4,5'-dihydroxy-6,6'-dialkylbiphenyl, 4,6'-dihydroxy-2,2'-dialkylbiphenyl, 4,6'-dihydroxy-3,3'-dialkylbiphenyl, 4,6'-dihydroxy-5,4'-dialkylbiphenyl, 4,6'-dihydroxy-6,5'-dialkylbiphenyl, and the like. These may be used alone or in combination of two or more.

[0024] Among the dihydroxybiphenyl derivatives represented by the above formula (5), 21 or R 31Examples of compounds having a methyl group as the aryl group include 4,4'-dihydroxy-3,3'-dimethylbiphenyl (CAS RN 612-84-0), 4,3'-dihydroxy-3,4'-dimethylbiphenyl, 3,3'-dihydroxy-2,2'-dimethylbiphenyl, 3,2'-dihydroxy-2,3'-dimethylbiphenyl, 3,3'-dihydroxy-4,2'-dimethylbiphenyl, 3,2'-dihydroxy-4,3'-dimethylbiphenyl, 4,2'-dihydroxy-3,3'-dimethylbiphenyl, etc. These may be used alone or in combination of two or more.

[0025] From the above, examples of the raw material resin include polymer 《1》 represented by the following formula (6) and polymer 《2》 represented by the following formula (7). These may be used alone or in combination of two or more. That is, more specifically, the raw material resin is a resin containing at least one of polymer 《1》 and polymer 《2》.

[0026] Polymer 1: A polymer having second units connected to each other via methylene groups and no first units. [ka]

[0027] The abundance ratio of the first units and the second units in this polymer 1 is m / (n+m)=1, where n is the number of the first units and m is the number of the second units. The range of m in the formula (6) is not limited, but can be, for example, 1 to 3,000. In formula (6), the number of repeating units with methylene groups in the second unit is expressed as m. Since this raw material resin has a structure with units via methylene groups, the number of repeating units is equal to the number of second units, so it can be expressed in this way. R in Equation (6) 21 and R 31 As mentioned above, R in formula (6) E1 is usually a hydrogen atom. Furthermore, R in (6) E2is usually a second unit (a structure in which a hydrogen atom is bonded to the end of the second unit represented by formula (2)). That is, in the raw material resin, the second unit can also form a polymerization end.

[0028] Polymer 2: A polymer having both first and second units connected to each other via a methylene group, and satisfying 0.05≦m / (n+m)<1, where n is the number of first units and m is the number of second units. [ka]

[0029] The range of m in formula (7) is not limited, but can be, for example, 1 to 3,000. In formula (7), the number of repeating structures in which the first unit has a methylene group is expressed as n, and the number of repeating structures in which the second unit has a methylene group is expressed as m. Since the raw material resin has a structure in which each unit is connected via a methylene group, the number of each repeating structure can be expressed in this way because it matches the number of first units or the number of second units. R in Equation (7) 11 , R 21 and R 31 is as described above. That is, R 11 , R 21 and R 31 At least some of R are monovalent substituents. 11 When at least a part of R is a monovalent substituent, a plurality of R 21 When at least a part of R is a monovalent substituent, a plurality of R 31 In addition, the case where at least a part of R 11 When R has a monovalent substituent, 21 and R 31 may or may not have a monovalent substituent. 21 When R has a monovalent substituent, 11 and R 31may or may not have a monovalent substituent. 31 When R has a monovalent substituent, 11 and R 21 may or may not have a monovalent substituent. In addition, when it does not have a monovalent substituent, it means that it is a hydrogen atom.

[0030] In addition, R in formula (7) E1 is usually a hydrogen atom. Furthermore, R in (7) E2 is usually a first unit (a structure in which a hydrogen atom is bonded to the end of a first unit represented by formula (1)) or a second unit (a structure in which a hydrogen atom is bonded to the end of a second unit represented by formula (2)). That is, in the raw material resin, the first unit and the second unit can also form a polymerization end.

[0031] In addition, it is convenient to express the polymer 2 as the above formula (7), but formula (7) does not mean that each unit (similar to the above-mentioned repeating structure) exists as a block. That is, the first unit (similar to the above-mentioned repeating structure containing the first unit) may exist in a block form or randomly. Of these, it is more preferable that the first unit exists randomly. The term "the first unit is present in a block form" refers to a case where there is a molecular chain region in which it is apparent that the first unit is present in greater numbers than the second unit. That is, for example, there is a case where there is a molecular chain region in which only methylene groups and the first unit are present alternately. The term "the first unit is present randomly" refers to a state in which the first unit is present evenly throughout the molecular chain. That is, there is no case where there is a molecular chain region in which it is apparent that the first unit is present in greater numbers than the second unit.

[0032] Similarly, the second unit (the same applies to the repeating structure containing the second unit described above) may be present in a block form or randomly, and among these, it is more preferable that it is present randomly. The second units being present in blocks refers to the case where there is a molecular chain region where it is apparent that there are more second units than first units. That is, for example, there is a molecular chain region where only methylene groups and second units are present alternately. The second units being present randomly refers to a state where the second units are present evenly throughout the molecular chain. That is, there is no molecular chain region where it is apparent that there are more second units than first units.

[0033] The abundance ratio of the first units to the second units in the polymer 2 satisfies 0.05≦m / (n+m)<1, where n is the number of the first units and m is the number of the second units. In this range, the acid decomposable resin obtained by using the present raw material resin can achieve excellent resolution and excellent heat resistance. The lower limit of m / (n+m) can be 0.10 or more, 0.15 or more, 0.20 or more, or 0.25 or more. On the other hand, the upper limit of m / (n+m) is not limited and can be 0.99, 0.95, 0.90, 0.85, or 0.80. These upper and lower limits can be appropriately combined. Therefore, for example, it can be 0.05 to 0.99, 0.10 to 0.95, 0.15 to 0.90, 0.20 to 0.85, or 0.25 to 0.80.

[0034] The raw material resin may be composed of only the first unit, the second unit, and the methylene group as the structural units, but may contain other structural units (other units) other than these. When the other structural units are contained, t / (n+m+s+t)<0.05, t / (n+m+s+t)<0.03, or t / (n+m+s+t)<0.01 can be satisfied, where n is the number of the first units, m is the number of the second units, s is the number of the methylene groups, and t is the number of the other structural units.

[0035] Examples of other structural units include structural units derived from phenolic compounds other than phenol and the above-mentioned phenol derivatives, structural units derived from dihydroxybiphenyl and other dihydroxybiphenyl derivatives other than the above-mentioned dihydroxybiphenyl derivatives, and structural units derived from aldehyde compounds other than formaldehyde. These may be used alone or in combination of two or more.

[0036] The other phenolic compounds include those having a monovalent substituent (R 11 ) is an amino group, a nitro group, an alkoxy group, or the like. Other examples include naphthols such as α-naphthol and β-naphthol, phenols (monohydric phenols) such as anthrols and hydroxypyrene, and their alkyl derivatives; polyhydric phenols such as resorcinol, hydroquinone, catechol, pyrogallol, and phloroglucin, and their alkyl derivatives; bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol M, bisphenol B, bisphenol C, and bisphenol S; trisphenols; tetraphenols; and the like. The number of phenolic hydroxyl groups possessed by the polyhydric phenol is not limited, but may be, for example, 2 to 3. These may be used alone or in combination of two or more. On the other hand, other dihydroxybiphenyl derivatives include those with monovalent substituents (R 21 Or R 31 ) is an amino group, a nitro group, an alkoxy group, etc. These may be used alone or in combination of two or more.

[0037] The other aldehyde compounds include aliphatic aldehydes and aromatic aldehydes, which may be used alone or in combination of two or more. Examples of aliphatic aldehydes include paraformaldehyde, polyoxymethylene, trioxane, tetraoxymethylene, glyoxal, acetaldehyde, paraaldehyde, propionaldehyde, propenaldehyde, butanal, hexanal, malondialdehyde, succindialdehyde, glutaric dialdehyde, allyl aldehyde, crotonaldehyde, and chloral. These can also be used as various solutions, such as formalin, which is an aqueous solution of formaldehyde. Furthermore, aldehyde-generating compounds such as hexamethylenetetramine that generate aldehyde compounds by decomposition can be used. These can be used alone or in combination of two or more.

[0038] Examples of aromatic aldehydes include furfural, benzaldehyde, phenylacetaldehyde, tolualdehyde (o-tolualdehyde, m-tolualdehyde, p-tolualdehyde), salicylaldehyde, naphthaldehyde, terephthalaldehyde, phenylbenzaldehyde, hydroxybenzaldehyde, etc. These may be used alone or in combination of two or more.

[0039] The raw material resin may be obtained by any method, but as described above, it can be obtained as a copolymer (addition condensate) of a phenolic compound and an aldehyde compound. The polymerization can be carried out using a catalyst according to a conventional method. Examples of the catalyst include acid catalysts, basic catalysts, and other catalysts. Among these, acid catalysts are preferred. The reaction conditions can be appropriately selected depending on the components used, but can be, for example, 60 to 150°C and 2 to 30 hours.

[0040] Among the above, examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid (including polyphosphoric acids such as metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, tetraphosphoric acid, and phosphoric anhydride), phosphorous acid, phosphonic acid, and the like; sulfates such as oxalic acid and diethyl sulfate, organic sulfonic acids, and organic phosphones, etc. These may be used alone or in combination of two or more kinds. Among the above, examples of the organic sulfonic acid include paratoluenesulfonic acid, benzenesulfonic acid, xylenesulfonic acid, etc. Furthermore, examples of the organic phosphonic acid include ethylenediaminetetrakismethylenephosphonic acid, ethylenediaminebismethylenephosphonic acid, aminotrismethylenephosphonic acid, β-aminoethylphosphonic acid N,N-diacetic acid, aminomethylphosphonic acid N,N-diacetic acid, 1-hydroxyethylidene-1,1'-diphosphonic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, etc.

[0041] Examples of the basic catalyst include metal hydroxides, metal oxides, amine compounds, etc. These may be used alone or in combination of two or more. Among these, examples of the metal hydroxide include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide; and the like. Examples of the metal oxide include alkaline earth metal oxides such as calcium oxide and magnesium oxide; and the like. Examples of the amine compound include aliphatic amines such as dimethylamine, triethylamine, butylamine, and the like; aromatic amines such as dimethylbenzylamine and naphthalenediamine; and the like. These may be used alone or in combination of two or more. Further examples include ammonia, ammonia generating compounds such as hexamethylenetetramine which generate ammonia by decomposition, naphthenates, etc. These may be used alone or in combination of two or more.

[0042] Other examples of the catalyst include metal compounds not included in the above. For example, divalent metal salts and divalent metal compounds, such as zinc compounds such as zinc oxide, zinc chloride, and zinc acetate, can be mentioned. These can be used alone or in combination of two or more.

[0043] In the synthesis, a reaction solvent can be used. Examples of the reaction solvent include ketone compounds, ester compounds, alcohol compounds, ether compounds, etc. These can be used alone or in combination of two or more. Among the above, examples of the ketone compound include methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, ethyl n-butyl ketone, diisopropyl ketone, diethyl ketone, di-n-propyl ketone, mesityl oxide, methyl n-amyl ketone, methyl n-butyl ketone, methyl n-propyl ketone, acetone, etc. These may be used alone or in combination of two or more.

[0044] Examples of the ester compound include methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, n-butyl acetate, sec-butyl acetate, isobutyl acetate, ethyl ethoxyacetate, ethyl oxyacetate, amyl acetate, isoamyl acetate, allyl acetate, ethyl isovalerate, propyl formate, butyl formate, isobutyl formate, isoamyl formate, diethyl carbonate, methyl propionate, ethyl propionate, butyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 3-methoxypropionate, isopropyl butyrate, ethyl butyrate, methyl butyrate, γ-butyrolactone, ethyl lactate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl acetoacetate, and ethyl acetoacetate. These may be used alone or in combination of two or more.

[0045] Examples of the alcohol compound include amyl alcohol (n-amyl alcohol, s-amyl alcohol, t-amyl alcohol), isoamyl alcohol, 2-ethylbutanol, 3,5-dimethyl-1-hexyne 3-ol, neopentyl alcohol, 2-methyl-1-butanol, 4-methyl-2-pentanol, ethylene glycol monoalkyl ether (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, etc.), diethylene glycol monobutyl ether, etc.), diethylene glycol dialkyl ether (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, etc.), propylene glycol monoalkyl ether (propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc.), etc. These may be used alone or in combination of two or more.

[0046] Examples of ether compounds include diethyl ether, ethyl isoamyl ether, ethyl t-butyl ether, 1,2-epoxybutane, diisopropyl ether, diethyl acetal, dibutyl ether, 2-methylfuran, ethylene glycol monoalkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, etc.), ethylene glycol dialkyl ethers (ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, etc.), diethylene glycol monoalkyl ethers (diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, etc.), diethylene glycol dialkyl ethers (diethylene glycol dimethyl ether, diethylene glycol Examples of the ethylene glycol alkyl ether include ethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, etc.), ethylene glycol alkyl ether acetate (methyl cellosolve acetate, ethyl cellosolve acetate, etc.), propylene glycol monoalkyl ether (propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc.), propylene glycol dialkyl ether (propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether, etc.), propylene glycol alkyl ether acetate (propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, etc.), and cyclic ethers (tetrahydrofuran, dioxane, etc.). These may be used alone or in combination of two or more.

[0047] The compounding ratio F / P (molar compounding ratio) of the phenol-based compound (P) to the aldehyde-based compound (F) when obtaining the raw material resin is not limited, but from the viewpoint of obtaining a novolak resin using an acidic catalyst, it is preferable that the compounding ratio is 0.8≦F / P≦1.5, more preferably that the compounding ratio is 0.90≦F / P≦1.30, and further preferably that the compounding ratio is 1.00≦F / P≦1.20.

[0048] The molecular weight of the raw material resin is not limited, but the lower limit of the weight average molecular weight is preferably 2,500 or more from the viewpoint of heat resistance. This weight average molecular weight can be 3,000 or more, 4,000 or more, 5,000 or more, or 6,000 or more. On the other hand, the upper limit of the weight average molecular weight is preferably 50,000 or less from the viewpoint of handling. This weight average molecular weight can be 40,000 or less, 35,000 or less, 30,000 or less, 25,000 or less, or 20,000 or less. These upper and lower limits can be appropriately combined with each other. Therefore, for example, it can be 1,000 to 50,000, further 2,000 to 40,000, further 3,000 to 35,000, further 4,000 to 30,000, further 5,000 to 25,000, and further 6,000 to 20,000. The method for measuring the weight average molecular weight will be described later.

[0049] The glass transition temperature of the raw resin is not limited, but according to the present raw resin, the glass transition temperature can be 85°C or higher. It can be 90°C or higher, 95°C or higher, 100°C or higher, 125°C or higher, 150°C or higher, or 180°C or higher. On the other hand, the upper limit of the glass transition temperature is not limited, but can be, for example, 300°C or lower, or 250°C or lower. These upper and lower limits can be appropriately combined. Therefore, for example, the glass transition temperature can be 85 to 300°C, 90 to 300°C, 95 to 300°C, 100 to 250°C, 125 to 250°C, 150 to 250°C, or 180 to 250°C. The method for measuring the glass transition temperature will be described later.

[0050] The alkaline dissolution rate (ADR) of the raw resin is not limited, but according to the present raw resin, the ADR can be 1000 Å / s or more, 1500 Å / s or more, 2000 Å / s or more, 2500 Å / s or more, 3000 Å / s or more, 3500 Å / s or more, 4000 Å / s or more, or 4500 Å / s or more. On the other hand, the upper limit of the ADR is not limited, but for example, it can be 10000 Å / s or less, 9500 Å / s or less, or 9000 Å / s or less. These upper and lower limits can be appropriately combined with each other. Therefore, for example, ADR can be 1000 to 10000 Å / s, 1500 to 10000 Å / s, 2000 to 9500 Å / s, 2500 to 9500 Å / s, 3000 to 9500 Å / s, 3500 to 9000 Å / s, 4000 to 9000 Å / s, or 4500 to 9000 Å / s. The method for measuring the alkali dissolution rate will be described later.

[0051] [2] Acid-decomposable resin The acid-decomposable resin of the present invention is characterized in that at least a portion of the hydrogen atoms constituting the hydroxyl groups constituting the above-mentioned raw material resin is substituted with monovalent acid-decomposable groups. That is, the acid-decomposable resin has units connected to each other via methylene groups, The unit includes a first unit represented by the following formula (8) and at least the second unit represented by the following formula (9), [ka] R in the above formula (8) 11 R in the formula (9) 21 R in the formula (9) 31 is at least partially a monovalent substituent, and the monovalent substituent is selected from the group consisting of an alkyl group and an aryl group having 1 to 5 carbon atoms (i.e., R 11 , R 21 and R 31 are each independently at least a portion of which is a monovalent substituent. R in the above formula (8) 12 R in the formula (9) 22 R in the formula (9) 32 At least a part of the group is a monovalent acid-decomposable group (i.e., R 12 , R 22 and R 32 each independently represents at least a monovalent acid-decomposable group.

[0052] The acid-decomposable resin may be obtained by any method, but can usually be obtained by introducing acid-decomposable groups into the above-mentioned raw material resin, i.e., by substituting at least some of the hydrogen atoms of the phenolic hydroxyl groups derived from the phenolic compound in the raw material resin with acid-decomposable groups. As described above, the raw resin has a plurality of first units and a plurality of second units. 12 , R 22 , R 32 Each of these R 12 , R 22 , R 32may all be acid-decomposable groups, or only a part of them may be acid-decomposable groups. 12 Only a part of R can be an acid-decomposable group. 22 Only a part of R can be an acid-decomposable group. 32 Only a portion of the group may be an acid-labile group.

[0053] The acid decomposable group is a group that is decomposed from the acid decomposable resin in the presence of an acid. The type of the acid decomposable group is not limited, but examples thereof include an alkoxyalkyl group, a tert-butoxycarbonyl group, and the like. These may be used alone or in combination of two or more kinds. Of the above, the alkoxyalkyl group is "R 81 -OR 82 -" In this formula, R 81 and R 82 are all hydrocarbon groups having 1 to 5 carbon atoms, and are usually saturated hydrocarbon groups. Specific examples include methoxymethyl group, 1-methoxyethyl group, 2-methoxyethyl group, 1-ethoxyethyl group, 2-ethoxyethyl group, 1-propoxyethyl group, 2-propoxyethyl group, 1-methoxypropyl group, 2-methoxypropyl group, 3-methoxypropyl group, 1-ethoxypropyl group, 2-ethoxypropyl group, and 3-ethoxypropyl group. These may be used alone or in combination of two or more.

[0054] From the above, examples of the acid-decomposable resin include polymer 《3》 represented by the following formula (10) and polymer 《4》 represented by the following formula (11). These may be used alone or in combination of two or more. That is, more specifically, the acid-decomposable resin is a resin containing at least one of polymer 《3》 and polymer 《4》.

[0055] Polymer 3: A polymer having second units connected to each other via methylene groups and no first units. [ka]

[0056] When the number of first units is n and the number of second units is m in the polymer 3, the abundance ratio of the first units to the second units is m / (n+m)=1. The range of m in the formula (10) is not limited, but may be, for example, 1 to 3,000. R in Equation (10) 21 and R 31 is as described above. R in formula (10) 22 and R 32 At least a part of R is an acid-decomposable group, and the other part is a hydrogen atom. That is, the polymer 3 has a plurality of second units, and at least a part of the plurality of second units has one or two acid-decomposable groups. 22 When at least a part of R 32 In addition, the case where at least a part of R 22 When R has an acid-decomposable group, 32 may or may not have an acid-decomposable group. 32 When R has an acid-decomposable group, 22 may or may not have an acid-decomposable group. Furthermore, R in formula (10) E1 is usually a hydrogen atom. E2 is usually a second unit (a structure in which a hydrogen atom is bonded to the end of the second unit represented by formula (9)). That is, in the raw material resin, the second unit can also form a polymerization end.

[0057] Polymer 4: A polymer having both first and second units connected to each other via a methylene group, and satisfying 0.05≦m / (n+m)<1, where n is the number of first units and m is the number of second units. [ka]

[0058] The range of m in formula (11) is not limited, but can be, for example, 1 to 3,000. R in Equation (11) 11 , R 21 and R 31 is as described above. R in formula (11) 12 , R 22 and R 32 At least a part of R is an acid-decomposable group, and the other part is a hydrogen atom. That is, the polymer 4 has a plurality of first units and a plurality of second units. At least a part of the plurality of first units has an acid-decomposable group. Furthermore, at least a part of the plurality of second units has one or two acid-decomposable groups. Therefore, the plurality of R 12 When at least a part of R 22 When at least a part of R 32 In addition, the case where at least a part of R 12 When R has an acid-decomposable group, 22 and R 32 may or may not have an acid-decomposable group. 22 When R has an acid-decomposable group, 12 and R 32 may or may not have an acid-decomposable group. 32 When R has an acid-decomposable group, 12 and R 22 may or may not have an acid-decomposable group.

[0059] Furthermore, R in formula (11) E1 is usually a hydrogen atom. Also, R in (11) E2 is usually a first unit (a structure in which a hydrogen atom is bonded to the end of a first unit represented by formula (8)) or a second unit (a structure in which a hydrogen atom is bonded to the end of a second unit represented by formula (9)). That is, in the raw material resin, the first unit and the second unit can also form a polymerization end.

[0060] In addition, it is convenient to express the polymer 4 as the above formula (11), but formula (11) does not mean that each unit exists as a block. That is, the first unit may exist in a block form or randomly. Of these, it is more preferable that the first unit exists randomly. The term "the first unit is present in a block form" refers to a case where there is a molecular chain region in which it is apparent that the first unit is present in greater numbers than the second unit. That is, for example, there is a case where there is a molecular chain region in which only methylene groups and the first unit are present alternately. The term "the first unit is present randomly" refers to a state in which the first unit is present evenly throughout the molecular chain. That is, there is no case where there is a molecular chain region in which it is apparent that the first unit is present in greater numbers than the second unit.

[0061] Similarly, the second units may be present in a block fashion or randomly, with the latter being more preferred. The second units being present in blocks refers to the case where there is a molecular chain region where it is apparent that there are more second units than first units. That is, for example, there is a molecular chain region where only methylene groups and second units are present alternately. The second units being present randomly refers to a state where the second units are present evenly throughout the molecular chain. That is, there is no molecular chain region where it is apparent that there are more second units than first units.

[0062] The ratio of the first unit to the second unit in the polymer 4 is the same as that of the raw material resin. Furthermore, the ratio of the structural units derived from the phenolic compound constituting the acid-decomposable resin to the structural units derived from the aldehyde compound constituting the acid-decomposable resin is also the same as that of the raw material resin. Furthermore, the acid-decomposable resin may be composed of only the first unit, the second unit, and a methylene group as structural units, but may also contain other structural units (other units) other than these, as is the case with the raw material resin.

[0063] The modification rate of the acid-decomposable resin by the acid-decomposable group is not limited, but can be 10% or more. In this range, better resolution and better heat resistance can be exhibited. The lower limit of this modification rate can be 12% or more, and can be 15% or more. On the other hand, the upper limit of the modification rate can be 50% or less, 48% or less, and 45% or more. These upper and lower limits can be appropriately combined. Therefore, for example, it can be 10 to 50%, 10 to 48%, 12 to 48%, 12 to 45%, or 15 to 45%. The modification rate is calculated as (N1 / N0)×100, where N0 is the total number of structural units derived from phenolic compounds and N1 is the number of structural units having an acid-decomposable group.

[0064] The molecular weight of the acid-decomposable resin is not limited, but the lower limit of its weight-average molecular weight is preferably 2,500 or more from the viewpoint of heat resistance. This weight-average molecular weight can be 3,000 or more, 4,000 or more, 5,000 or more, or 6,000 or more. On the other hand, the upper limit of its weight-average molecular weight is preferably 50,000 or less from the viewpoint of handling. This weight-average molecular weight can be 40,000 or less, 35,000 or less, 30,000 or less, 25,000 or less, or 20,000 or less. These upper and lower limits can be appropriately combined with each other. Therefore, for example, it can be 1,000 to 50,000, further 2,000 to 40,000, further 3,000 to 35,000, further 4,000 to 30,000, further 5,000 to 25,000, and further 6,000 to 20,000. The method for measuring the weight average molecular weight will be described later.

[0065] The glass transition temperature of the acid-decomposable resin is not limited, but according to the present raw material resin, the glass transition temperature can be 60°C or higher. It can be 65°C or higher, 70°C or higher, 75°C or higher, 80°C or higher, 85°C or higher, or 90°C or higher. On the other hand, the upper limit of the glass transition temperature is not limited, but can be, for example, 200°C or lower, or 150°C or lower. These upper and lower limits can be appropriately combined. Therefore, for example, the glass transition temperature can be 60 to 200°C, 65 to 200°C, 70 to 200°C, 75 to 150°C, 80 to 150°C, 85 to 150°C, or 90 to 150°C. The method for measuring the glass transition temperature will be described later.

[0066] [3] Photosensitive resin composition The above-mentioned acid-decomposable resin can be used in a photosensitive resin composition. That is, a photosensitive resin composition can be prepared containing the above-mentioned acid-decomposable resin, a photoacid generator, and a solvent. This photosensitive resin composition can form a photosensitive resin film having excellent heat resistance.

[0067] The amount of the acid-decomposable resin contained in the photosensitive resin composition is not limited, but can be 50 to 99% by mass, 55 to 98% by mass, or 65 to 97% by mass, assuming that the total non-volatile components (components in the photosensitive resin composition other than the solvent) is 100% by mass.

[0068] The photoacid generator includes a compound that generates an acid by irradiation with light. Any photoacid generator can be used, and examples of the photoacid generator include nonionic photoacid generators and ionic photoacid generators. These may be used alone or in combination of two or more.

[0069] Examples of nonionic photoacid generators include organic halides, sulfonate esters, and sulfones. These may be used alone or in combination of two or more. Among the above, examples of sulfonate esters include 2-nitrobenzyl esters, aromatic sulfonates, oxime sulfonates, N-sulfonyloxyimides, sulfonyloxyketones, and diazonaphthoquinone 4-sulfonates. These may be used alone or in combination of two or more. Examples of sulfones include disulfones, ketosulfones, and sulfonyldiazomethanes. These may be used alone or in combination of two or more.

[0070] Examples of the ionic photoacid generator include onium salts containing onium cations. Examples of the onium salts containing onium cations include diazonium salts, phosphonium salts, sulfonium salts, and iodonium salts. These may be used alone or in combination of two or more. Examples of the anions of the onium salts include sulfonate anions, sulfonylimide anions, and sulfonylmethide anions. These may be used alone or in combination of two or more.

[0071] Among the above, ionic photoacid generators are preferred, and onium salts containing an onium cation are more preferred. In addition, the photoacid generator preferably contains a compound that generates a fluorine-containing acid as an acid. By containing such a compound (a compound that generates a fluorine-containing acid), the sensitivity can be improved. An example of such a compound is a fluorinated alkyl phosphate sulfonium salt. This fluorinated alkyl phosphate sulfonium salt can be represented by the following formula (12).

[0072] [ka]

[0073] R in Equation (12) 51 , R 52 and R 53are each independently a hydrogen atom or a monovalent substituent, and R in formula (12) f is a fluorinated alkyl group, and n in formula (12) is an integer of 1 to 6.

[0074] Examples of the monovalent substituent include an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, a hydroxy group, a carboxy group, an alkoxy group, an aryloxy group, an arylthio group, etc. The number of carbon atoms constituting the monovalent substituent is not limited, but can be 1 to 10. Among these, it is preferable to have an arylthio group, and more preferably to have a phenylthio group (C6H5-S-). In the case where the phenylthio group is present, the phenylthio group is represented by R 51 , R 52 and R 53 and the others are preferably hydrogen atoms. The fluorinated alkyl group may be a perfluoroalkyl group. f The number of carbon atoms constituting the group is not limited, but may be 1-10.

[0075] The amount of the photoacid generator contained in the photosensitive resin composition is not limited, but can be 0.1 to 10 mass%, 0.3 to 8 mass%, or 0.5 to 6 mass%, assuming that the total non-volatile components (components of the photosensitive resin composition other than the solvent) is 100 mass%.

[0076] The type of the solvent is not limited, and any solvent can be used, but typically it is an organic solvent. Examples of organic solvents include glycol ether esters, glycol ethers, esters, ketones, lactones, etc. These may be used alone or in combination of two or more. Among these, examples of glycol ether esters include ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, etc. Examples of glycol ethers include propylene glycol monomethyl ether, etc. Examples of esters include ethyl lactate, butyl acetate, amyl acetate, ethyl pyruvate, etc. Examples of lactones include γ-butyrolactone, etc. Examples of ketones include acyclic ketones and cyclic ketones. Among these, examples of acyclic ketones include acetone, methyl isobutyl ketone, 2-heptanone, etc. Examples of cyclic ketones include cyclohexanone, cyclopentanone, etc. These may be used alone or in combination of two or more.

[0077] Among the above, it is preferable that the solvent contains a cyclic ketone, more preferably 90 mass % or more of the total amount of the solvent, still more preferably 95 mass % or more of the total amount of the solvent, and particularly preferably the entire amount of the solvent is a cyclic ketone. By using a cyclic ketone as a solvent, it is possible to suppress the deterioration of the photosensitive resin composition over time during storage. More specifically, it is possible to suppress the decrease in the residual film ratio even after the photosensitive resin composition is stored for a long period of time, such as about six months or more. Furthermore, the cyclic ketone solvent is less likely to remain inside the photosensitive resin film (a film obtained by forming a photosensitive resin composition) than other solvents (such as commonly used propylene glycol monomethyl ether acetate). This makes it possible to make the alkali solubility of the entire photosensitive resin film more uniform. As a result, it is possible to improve the rectangularity and aspect ratio of the pattern. The effect of improving the rectangularity of the pattern and the aspect ratio can also be obtained when, for example, an alkyl lactate (ethyl lactate, etc.) is used as a solvent.

[0078] The photosensitive resin composition may contain other components than the acid-decomposable resin, the photoacid generator, and the solvent. That is, the photosensitive resin composition may be one that does not contain other components than the acid-decomposable resin, the photoacid generator, and the solvent, but it may be one that contains the acid-decomposable resin, the photoacid generator, the solvent, and other components.

[0079] Examples of other components include quenchers, anticorrosives (such as anticorrosives for the substrate), surfactants, sensitizers, dissolution inhibitors, stabilizers, antioxidants, and other additives known in the photoresist field. These may be used alone or in combination of two or more. Among the above, the quencher is a compound that has the effect of capturing the acid generated from the photoacid generator. Specific examples include amines, ammonium salts, nitrogen-containing heterocyclic compounds exhibiting basicity, etc. These may be used alone or in combination of two or more. Among the above, the amines include aliphatic amines and aromatic amines. The aliphatic amines include primary amines, secondary amines, and tertiary amines. The aliphatic amines include monoalkylamines, dialkylamines, and trialkylamines. The aromatic amines include aniline and aniline derivatives.

[0080] Among the above, examples of the aliphatic amines include hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, dibutylmethylamine, methyldipentylamine, Examples of the amines include dihexylmethylamine, dicyclohexylmethylamine, diheptylmethylamine, methyldioctylamine, methyldinonylamine, didecylmethylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, and hexamethylenediamine. Among the above, examples of aromatic amines include naphthylamine, aniline, diisopropylaniline, methylaniline, nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, and 4,4'-diamino-3,3'-diethyldiphenylmethane.

[0081] The concentration of the non-volatile components of the photosensitive resin composition (components other than the solvent in the photosensitive resin composition) is not limited, but is preferably 30 to 60 mass %, more preferably 45 to 60 mass %. Within these preferred ranges, a relatively thick photosensitive resin film with a uniform thickness can be formed using a spin coater. As a result, a pattern with a high aspect ratio can be obtained. The concentration of the photosensitive resin composition may be adjusted in any way, for example, by changing the amount and type of the above-mentioned solvent.

[0082] The photosensitive resin composition exhibits good performance in forming a relatively thick pattern. More specifically, in forming a pattern with a high aspect ratio (the aspect ratio is the value of "height / line width" of the pattern), the shape of the pattern can be easily made rectangular. In addition, the effects of a high aspect ratio and rectangular pattern shape can be more reliably obtained by appropriately selecting a solvent. For example, a high aspect ratio and rectangular pattern shape can be obtained by using the above-mentioned cyclic ketone or alkyl lactate as a solvent. That is, by increasing the concentration of the non-volatile components (components other than the solvent) of the photosensitive resin composition as described above, it becomes easier to form a thick resin film, and by patterning the thick resin film, a pattern with a high aspect ratio can be obtained.

[0083] The viscosity of the photosensitive resin composition is not limited, but is preferably 50 to 10,000 mPa·s, more preferably 300 to 10,000 mPa·s, and even more preferably 500 to 4,000 mPa·s at 25°C. Within these preferred ranges, a photosensitive resin film that is relatively thick but has a uniform thickness can be formed using a spin coater. As a result, a pattern with a high aspect ratio can be obtained. The viscosity of the photosensitive resin composition may be adjusted in any way, for example, by changing the amount and type of the above-mentioned solvent. The viscosity of the photosensitive resin composition can be measured by a rotational viscometer, a Cannon-Fenske viscometer using a capillary tube, or a tuning fork type vibration viscometer (such as an A&D device, model number SV-10).

[0084] [4] Pattern formation method A pattern can be formed by using the above-mentioned photosensitive resin composition. That is, a pattern forming method can be provided that includes a film forming step of forming a photosensitive resin film using the photosensitive resin composition, an exposure step of exposing the photosensitive resin film, and a development step of developing the photosensitive resin film. According to this pattern forming method, the photosensitive resin film having excellent heat resistance can be used for patterning, so that the degree of freedom in pattern design can be improved.

[0085] The film formation step is a step of forming a photosensitive resin film using a photosensitive resin composition, i.e., a step of laminating a photosensitive resin film on a substrate. The type of substrate is not limited, and examples thereof include various wafers (Si wafers, SiC wafers, GaN wafers, etc.), glass substrates, ceramic substrates, metal substrates (aluminum substrates, copper substrates, etc.), plated substrates (copper plated substrates), etc. These may be used alone or in combination of two or more. These substrates may be unprocessed substrates or substrates on which electrodes, elements, etc. are formed on the surface.

[0086] The method for forming the photosensitive resin film is not limited, and a known forming method used in the field of electronic device manufacturing can be appropriately applied. That is, for example, spin coating using a spinner, spray coating using a spray coater, dip coating, printing (inkjet method, etc.), coating by roll coating, etc. can be mentioned. These can be used alone or in combination of two or more.

[0087] In addition, the photosensitive resin composition applied on the substrate is usually turned into a photosensitive resin film by removing the solvent contained therein, so the film formation step can include a solvent removal step. The method for removing the solvent is not limited, but can be performed, for example, by heat treatment. The heating temperature in the heat treatment is not limited, but is, for example, 80 to 140°C, preferably 90 to 120°C. In addition, the heating time is not limited and can be appropriately set depending on the heating device used, but for example, when a hot plate is used, it can be 30 to 300 seconds, preferably 60 to 180 seconds. In addition, when a hot air oven is used, it can be 5 to 60 minutes, preferably 10 to 30 minutes.

[0088] The thickness of the photosensitive resin film to be formed is not limited and can be adjusted appropriately depending on the application to be applied, the pattern to be finally obtained, etc. For example, when the purpose is to form copper bumps, the thickness can be 5 to 100 μm, preferably 10 to 100 μm, and more preferably 15 to 100 μm. This thickness can be adjusted by adjusting the concentration of the non-volatile components described above, selecting the coating method, etc.

[0089] The exposure step is a step of exposing the photosensitive resin film to light, which can be performed by applying actinic rays to the photosensitive resin film through a suitable photomask. Examples of actinic rays include X-rays, electron beams, ultraviolet rays, and visible rays. In terms of wavelength, light of 200 to 500 nm is preferred. In terms of pattern resolution and ease of handling, the light source is preferably g-ray, h-ray, or i-ray from a mercury lamp, and particularly preferably i-ray. Only one type of light may be used, or two or more types of light may be used in combination. The exposure step can be carried out using an exposure device. Examples of the exposure device include a contact aligner, a mirror projection, a stepper, etc. These devices may be used alone or in combination of two or more. The amount of light exposure in the exposure process is not limited, but is preferably 100 to 500 mJ / cm 2 The amount of exposure can be appropriately adjusted depending on the amount of the photosensitizer in the photosensitive resin film.

[0090] The development step is a step of developing the photosensitive resin film, that is, a step of developing the exposed photosensitive resin film with a developer to obtain a desired pattern. The development may be carried out by any method, such as a dipping method, a paddle method, a rotary spray method, etc. These may be used alone or in combination of two or more. By development, for example, the exposed portion of the photosensitive resin film is dissolved and removed, and a positive pattern can be obtained.

[0091] The type of developer is not limited, but an alkaline liquid is usually used. Examples of the developer include an inorganic alkaline aqueous solution, an organic amine aqueous solution, and a quaternary ammonium salt aqueous solution. These may be used alone or in combination of two or more. Among these, examples of solutes of inorganic alkaline aqueous solutions include sodium hydroxide, sodium carbonate, sodium silicate, ammonia, etc. Examples of solutes of organic amine aqueous solutions include ethylamine, diethylamine, triethylamine, triethanolamine, etc. Examples of solutes of quaternary ammonium salt aqueous solutions include tetramethylammonium hydroxide, tetrabutylammonium hydroxide, etc. These may be used alone or in combination of two or more. Among the above, the developer is preferably an aqueous solution of tetramethylammonium hydroxide. The concentration of tetramethylammonium hydroxide in this aqueous solution is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass.

[0092] The pattern forming method may include other steps in addition to the film forming step, the exposure step, and the development step. The other steps include a heating step for heating the photosensitive resin film, a rinsing step, etc. These steps may be used alone or in combination of two or more.

[0093] Among the above, the heating step is a step of heating the photosensitive resin film after the exposure step and before the development step (post exposure bake). The heating temperature in the heating step is not limited, but is preferably 70 to 150°C, more preferably 70 to 120°C. In addition, the heating time in the heating step is preferably 30 to 300 seconds, more preferably 60 to 180 seconds, for example, when a hot plate is used. By providing a heating step, that is, by performing post-exposure baking, the deprotection reaction can be promoted, and further high sensitivity can be achieved. On the other hand, since 1-ethoxyethyl group and 1-propoxyethyl group as acid decomposable groups are groups that are easily deprotected, sufficient deprotection is possible without providing a heating step after exposure. In other words, high sensitivity can be obtained without post-exposure baking. This leads to a reduction in the number of steps and the number of devices, and functions as a factor for improving production efficiency.

[0094] Among the above, the rinsing step is a step of cleaning the pattern and / or the substrate with a rinsing liquid after the developing step. Ultrapure water can be suitably used as the rinsing liquid.

[0095] Furthermore, by using the pattern obtained by the above-mentioned pattern forming method as a mask, electronic devices can be manufactured. Examples of the mask include a mask for dry etching, a mask for ion implantation process, a mask for metal sputtering, a mask for metal plating, etc. These may be used alone or in combination of two or more kinds. That is, the method for manufacturing an electronic device may include a dry etching step, an ion implantation process step, a metal sputtering step, a metal plating step, etc., in which the pattern obtained by the above-mentioned pattern formation method is used as a mask. These steps may be used alone or in combination of two or more.

[0096] Examples of the electronic device include a semiconductor chip, a semiconductor element, a printed wiring board, an electric circuit display device, an information and communication terminal, a light-emitting diode, a physical battery, a chemical battery, etc. In other words, the electronic device includes an element, a device, a final product, etc. to which electronic engineering technology is applied. EXAMPLES

[0097] The present invention will now be described in more detail with reference to examples. [1] Preparation of raw resin The following eight kinds of raw material resins (Examples 1-1 to 1-5, Comparative Examples 1-1 to 1-3) were prepared. The weight average molecular weight (Mw), glass transition temperature (Tg), and alkaline dissolution rate (ADR) of these raw material resins were measured. The results are shown in Table 1. The measurement methods are described below.

[0098] [Example 1-1] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 270 parts by mass of o-cresol as a phenolic compound, 229 parts by mass of 4,4'-dihydroxy-3,3'-dimethylbiphenyl, 119 parts by mass of formaldehyde as an aldehyde compound, and an acid catalyst were added and reacted at 100°C for 5 hours, and then a purification operation was performed to obtain a raw material resin of Example 1-1. The weight average molecular weight (Mw) of the obtained raw material resin of Example 1-1 was 3809, the glass transition temperature (Tg) was 119°C, and the alkaline dissolution rate (ADR) was 4073 Å / s.

[0099] [Example 1-2] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 270 parts by mass of o-cresol as a phenolic compound, 229 parts by mass of 4,4'-dihydroxy-3,3'-dimethylbiphenyl, 133 parts by mass of formaldehyde as an aldehyde compound, and an acid catalyst were added and reacted at 100°C for 5 hours, and then a purification operation was performed to obtain a raw material resin of Example 1-2. The weight average molecular weight (Mw) of the obtained raw material resin of Example 1-2 was 6997, the glass transition temperature (Tg) was 157°C, and the alkaline dissolution rate (ADR) was 1662 Å / s.

[0100] [Examples 1-3] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 500 parts by mass of 4,4'-dihydroxy-3,3'-dimethylbiphenyl as a phenolic compound, 227 parts by mass of formaldehyde as an aldehyde compound, an acidic catalyst, and a reaction solvent were each charged and reacted at 100°C for 10 hours, and then a purification operation was performed to obtain a raw material resin of Example 1-3. The weight average molecular weight (Mw) of the obtained raw material resin of Example 1-3 was 11576, the glass transition temperature (Tg) was 197°C, and the alkaline dissolution rate (ADR) was 6855 Å / s.

[0101] [Examples 1-4] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 500 parts by mass of 4,4'-dihydroxy-3,3'-dimethylbiphenyl as a phenolic compound, 227 parts by mass of formaldehyde as an aldehyde compound, an acidic catalyst, and a reaction solvent were added and reacted at 100°C for 14.5 hours, and then a purification operation was performed to obtain a raw material resin of Example 1-4. The weight average molecular weight (Mw) of the obtained raw material resin of Example 1-4 was 14260, the glass transition temperature (Tg) was 199°C, and the alkaline dissolution rate (ADR) was 6299 Å / s.

[0102] [Comparative Example 1-1] 500 parts by mass of o-cresol as a phenolic compound, 158 parts by mass of formaldehyde as an aldehyde compound, and an acid catalyst were added to a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, and reacted at 100°C for 5 hours, and then purified to obtain a raw material resin of Comparative Example 1-1. The weight average molecular weight (Mw) of the obtained raw material resin of Comparative Example 1-1 was 3795, the glass transition temperature (Tg) was 95°C, and the alkaline dissolution rate (ADR) was 1799 Å / s.

[0103] [Comparative Example 1-2] 500 parts by mass of o-cresol as a phenolic compound, 166 parts by mass of formaldehyde as an aldehyde compound, and an acid catalyst were added to a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, and reacted at 100°C for 5 hours, and then purified to obtain a raw material resin of Comparative Example 1-2. The weight average molecular weight (Mw) of the obtained raw material resin of Comparative Example 1-2 was 4336, the glass transition temperature (Tg) was 102°C, and the alkaline dissolution rate (ADR) was 127 Å / s.

[0104] [Comparative Example 1-3] 500 parts by mass of o-cresol as a phenolic compound, 169 parts by mass of formaldehyde as an aldehyde compound, and an acid catalyst were added to a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, and reacted at 100°C for 5 hours, and then purified to obtain a raw material resin of Comparative Example 1-3. The weight average molecular weight (Mw) of the obtained raw material resin of Comparative Example 1-3 was 6828, the glass transition temperature (Tg) was 108°C, and the alkaline dissolution rate (ADR) was 575 Å / s.

[0105] [Table 1]

[0106] [2] Preparation of acid-decomposable resin The following seven types of acid-decomposable resins (Examples 2-1 to 2-4, Comparative Examples 2-1 to 2-3) were prepared. The modification rate (%), weight average molecular weight (Mw), and glass transition temperature (Tg) of these acid-decomposable resins were measured. The results are shown in Table 2. The measurement methods are described below.

[0107] [Example 2-1] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 120 parts by mass of the raw resin obtained in Example 1-1, an acid catalyst, and a reaction solvent were each added, and then 30 parts by mass of 1-propyl vinyl ether was further added and reacted at 40°C for 3 hours, followed by purification to obtain an acid-decomposable resin of Example 2-1. The acid-modified group of the obtained acid-decomposable resin of Example 2-1 was 1-propoxyethyl, and the modification rate (%) was 31%. Furthermore, the weight average molecular weight (Mw) was 4152, and the glass transition temperature (Tg) was 71°C.

[0108] [Example 2-2] In a reaction vessel equipped with a thermometer, a stirrer and a reflux condenser, 120 parts by mass of the raw resin obtained in Example 1-2, an acid catalyst and a reaction solvent were added, and then 24 parts by mass of 1-propyl vinyl ether was added and reacted at 40°C for 3 hours, followed by purification to obtain an acid-decomposable resin of Example 2-2. The acid-modified group of the acid-decomposable resin of Example 2-2 obtained was 1-propoxyethyl, and the modification rate (%) was 22%. Furthermore, the weight average molecular weight (Mw) was 8003 and the glass transition temperature (Tg) was 97°C.

[0109] [Example 2-3] In a reaction vessel equipped with a thermometer, a stirrer and a reflux condenser, 120 parts by mass of the raw resin obtained in Example 1-3, an acid catalyst and a reaction solvent were added, and then 34 parts by mass of 1-propyl vinyl ether was added and reacted at 40°C for 3 hours, followed by purification to obtain an acid-decomposable resin of Example 2-3. The acid-modified group of the acid-decomposable resin of Example 2-3 obtained was 1-propoxyethyl, and the modification rate (%) was 42%. Furthermore, the weight average molecular weight (Mw) was 11921 and the glass transition temperature (Tg) was 98°C.

[0110] [Example 2-4] In a reaction vessel equipped with a thermometer, a stirrer and a reflux condenser, 120 parts by mass of the raw resin obtained in Example 1-3, an acid catalyst and a reaction solvent were added, and then 34 parts by mass of 2-propyl vinyl ether was added and reacted at 40°C for 3 hours, followed by purification to obtain an acid-decomposable resin of Example 2-4. The acid-modified group of the acid-decomposable resin of Example 2-4 obtained was 2-propoxyethyl, and the modification rate (%) was 38%. Furthermore, the weight average molecular weight (Mw) was 11980 and the glass transition temperature (Tg) was 99°C.

[0111] [Comparative Example 2-1] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 120 parts by mass of the raw resin obtained as Comparative Example 1-1, an acid catalyst, and a reaction solvent were each added, and then 24 parts by mass of 1-propyl vinyl ether was further added and reacted at 40°C for 3 hours, followed by purification to obtain an acid-decomposable resin of Comparative Example 2-1. The acid-modified group of the obtained acid-decomposable resin of Comparative Example 2-1 was 1-propoxyethyl, and the modification rate (%) was 30%. Furthermore, the weight average molecular weight (Mw) was 4152, and the glass transition temperature (Tg) was less than 36°C.

[0112] [Comparative Example 2-2] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 120 parts by mass of the raw resin obtained as Comparative Example 1-2, an acid catalyst, and a reaction solvent were each added, and then 24 parts by mass of 1-propyl vinyl ether was further added and reacted at 40°C for 3 hours, and then a purification operation was performed to obtain an acid-decomposable resin of Comparative Example 2-2. The acid-modified group of the obtained acid-decomposable resin of Comparative Example 2-2 was 1-propoxyethyl, and the modification rate (%) was 19%. Furthermore, the weight average molecular weight (Mw) was 4741, and the glass transition temperature (Tg) was 42°C.

[0113] [Comparative Example 2-3] In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, 120 parts by mass of the raw resin obtained as Comparative Example 1-3, an acid catalyst, and a reaction solvent were each added, and then 24 parts by mass of 1-propyl vinyl ether was further added and reacted at 40°C for 3 hours, followed by purification to obtain an acid-decomposable resin of Comparative Example 2-3. The acid-modified group of the obtained acid-decomposable resin of Comparative Example 2-3 was 1-propoxyethyl, and the modification rate (%) was 25%. Furthermore, the weight average molecular weight (Mw) was 7228, and the glass transition temperature (Tg) was 47°C.

[0114] [Table 2]

[0115] (1) Weight average molecular weight (Mw) The weight average molecular weight was measured under the following conditions using a high-speed GPC device (manufactured by Tosoh Corporation, model number "HCL-8320GPC") and a column compatible with the high-speed GPC device (manufactured by Tosoh Corporation, product names "TSKGel G2000HXL, G4000HXL"), and was converted using a calibration curve of standard polystyrene (manufactured by Tosoh Corporation, product names "F-40, F-20, F-10, F-4, F-2, F-1, A5000, A2500, A1000", manufactured by Tokyo Chemical Industry Co., Ltd., product name "2,2-methylenebis(4-methylphenol)", and manufactured by Kanto Chemical Co., Ltd., product name "p-cresol"). Solvent: Tetrahydrofuran (THF) Measurement temperature: 40℃ Flow rate: 1mL / min Sample concentration: Example: 3 mg / THF 5 mL, Comparative Example: 30 mg / THF 5 mL Injection volume: 100μL

[0116] (2) Glass transition temperature (Tg) The glass transition temperature was measured using a differential scanning calorimeter (Rigaku Corporation, model "Thermo plus EVO2 DSC8231"). In this case, the DSC chart was obtained by heating at a heating rate of 5°C / min in the range of 25 to 250°C for the raw material resin and in the range of 25 to 180°C for the acid-decomposable resin, cooling, and then heating again. The glass transition temperature was read as the inflection point (based on the glass transition) of the baseline in the obtained DSC chart. For measurement objects containing solvent, the solvent was removed before measurement.

[0117] (3) Alkaline Dissolution Rate (ADR) The alkaline dissolution rate was measured by the following method. That is, the raw resin solution obtained as described above by adding a solvent (ethyl cellosolve acetate) to each raw resin to adjust the viscosity was applied to the surface of a silicon wafer using a spin coater, and then heated at 100°C for 90 seconds to obtain a coating film. The thickness D (Å) of the obtained coating film was measured using a reflection spectroscopic film thickness meter (manufactured by Otsuka Electronics Co., Ltd., model "FE-3000"). Then, the silicon wafer having the coating film was immersed in a tetramethylammonium hydroxide solution with a concentration of 2.38 mass%, and the dissolution time T (seconds) until the coating film was dissolved was measured. Then, the value obtained by dividing the film thickness D by the dissolution time T was calculated as the alkaline dissolution rate (ADR).

[0118] (4) Modification rate of acid-decomposable groups (%) The modification rate of acid-decomposable groups was measured using a nuclear magnetic resonance apparatus (manufactured by JEOL Ltd., model number "JNM-ECZ400S"). 13 Measured by C-NMR (observed nuclei: 13 C, solvent: dimethylsulfoxide-d6, standard substance: tetramethylsilane, number of integrations: 10240). Specifically, it was calculated as the ratio of the integral value of the peaks (156 to 148 ppm) attributable to the hydroxyl groups of the acid-decomposable resin or aromatic carbons to which acid-dissociable groups are bonded to the integral value of the peaks attributable to the acid-decomposable groups (1-propoxyethyl: 105 to 98 ppm, 2-propoxyethyl: 105 to 98 ppm).

[0119] [3] Effects of the embodiment The raw material resin of Comparative Example 1-1 in Table 1 has all first units, and the raw material resin of Example 1-1 in Table 1 has 70% first units and 30% second units of all units. Both have almost the same Mw of 3795 and 3809, but the Tg of Example 1-1 is 25% higher and the ADR is 2.26 times larger than those of Comparative Example 1-1. In the raw material resin of Comparative Example 1-3 in Table 1, all units are first units, and in the raw material resin of Example 1-2 in Table 1, 70% of all units are first units and 30% are second units. Both have almost the same Mw of 6828 and 6997, but the Tg of Example 1-2 is 45% higher and the ADR is 2.89 times larger than those of Comparative Example 1-3. An ADR of 1662 Å / s, which is almost the same as the ADR of 1799 Å / s obtained from the raw material resin of Comparative Example 1-1, can be obtained from Example 1-2, but the Tg of Example 1-2 is 65% higher than that of Comparative Example 1-1. Therefore, compared to conventional raw material resins, it is possible to realize a significantly superior heat resistance temperature and a superior dissolution rate, which can be controlled over a wide range.

[0120] It is clear from Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-3 that Tg tends to decrease with an increase in the modification rate of the acid-decomposable group. In Comparative Example 2-2, an acid-decomposable group was introduced at a modification rate of 19% into the raw material resin of Comparative Example 1-2 (Tg = 102°C), resulting in a 58.8% decrease in Tg. In Comparative Example 2-3, an acid-decomposable group was introduced at a modification rate of 25% into the raw material resin of Comparative Example 1-3 (Tg = 108°C), resulting in a 56.5% decrease in Tg. In Comparative Example 2-1, an acid-decomposable group was introduced at a modification rate of 30% into the raw material resin of Comparative Example 1-1 (Tg = 95°C), resulting in a 61.5% decrease in Tg. In Example 2-2, an acid-decomposable group was introduced into the raw material resin of Example 2-2 (Tg = 157°C) at a modification rate of 22%, resulting in a 38.2% decrease in Tg. In Example 2-1, an acid-decomposable group was introduced into the raw material resin of Example 1-1 (Tg = 119°C) at a modification rate of 31%, resulting in a 40.3% decrease in Tg. In Example 2-4, an acid-decomposable group was introduced into the raw material resin of Example 1-3 (Tg = 197°C) at a modification rate of 38%, resulting in a 50.9% decrease in Tg. In Example 2-3, an acid-decomposable group was introduced into the raw material resin of Example 1-3 (Tg = 197°C) at a modification rate of 42%, resulting in a 50.3% decrease in Tg. Therefore, it is understood that, in comparison with the comparative example, in the examples, the decrease in Tg is suppressed to a smaller extent even when the modification rate is increased.

Claims

1. A raw material resin that becomes an acid-decomposable resin by introducing an acid-decomposable group, The raw material resin has units connected to each other via methylene groups, The unit includes a first unit represented by the following formula (1) and at least the second unit represented by the following formula (2): 【Chemistry 1】 R in the formula (1) １１ , R in the formula (2) ２１ , R in the formula (2) ３１ is at least partially a monovalent substituent, The raw material resin is characterized in that the monovalent substituent is selected from the group consisting of alkyl groups and aryl groups having 1 to 5 carbon atoms.

2. 2. The raw material resin according to claim 1, wherein, when the number of the first units is n and the number of the second units is m, 0.05≦m / (n+m)≦1 is satisfied.

3. 2. The raw material resin according to claim 1, which has a weight average molecular weight of 2,500 or more.

4. 2. The raw material resin according to claim 1, which has a glass transition temperature of 85° C. or higher.

5. 2. An acid-decomposable resin, comprising: at least a portion of hydrogen atoms constituting hydroxyl groups constituting the raw material resin according to claim 1 substituted with monovalent acid-decomposable groups.

6. 6. The acid-decomposable resin according to claim 5, wherein the modification rate with the acid-decomposable group is 10% or more.

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