Positive photosensitive resin composition, resist film, resist underlayer film, and permanent resist film

Abstract

To provide a positive photosensitive resin composition from which a resist film having high i-line transmittance, excellent developability and excellent heat resistance can be obtained, and which also exhibits good storage stability.SOLUTION: A positive photosensitive resin composition comprises the following components (A) to (C): (A) a novolac-type phenolic resin having acetal-based protecting groups and including a phenolic structural unit (a1) derived from m-cresol and / or o-cresol, an aldehyde structural unit (a2) derived from acetaldehyde, and an aldehyde structural unit (a3) derived from salicylaldehyde; (B) a photoacid generator; and (C) a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a positive photosensitive resin composition, a resist film, a resist underlayer film, and a permanent resist film. [Background technology]

[0002] In recent years, the miniaturization of electronic devices has led to an increase in the density of semiconductor packages. Conventionally, positive i-line photoresists incorporating alkali-soluble resins (e.g., novolac-type phenolic (phenol novolac) resins) and naphthoquinone diazide compound-based photosensitizers have been widely used in the manufacture of IC and LSI semiconductor packages. However, miniaturization using i-line is reaching its limits. In particular, plating resists for forming rewiring layers used in advanced semiconductor packages are required to form fine wiring in films thicker than several tens of micrometers. In thick films of several tens of micrometers, exposure treatment of conventional photosensitive resin compositions using naphthoquinone diazide compound-based photosensitizers does not allow a sufficient amount of light to reach the bottom of the film, preventing alkali dissolution of the resist layer at the bottom of the pattern, making it difficult to form high-aspect ratio patterns.

[0003] To address the above-mentioned issues, it has been considered to use chemically amplified positive photoresists, which are used in photolithography using excimer lasers such as KrF, ArF, and EUV, in photolithography using i-line, instead of using naphthoquinone diazide compound-based photosensitizers (for example, Patent Document 1). When a photosensitive resin film using chemically amplified positive photoresist is irradiated with light, acid is generated from the photoacid generator, and the generated acid (protons) acts as an acid catalyst to remove the protecting groups of the acid-decomposable resin, exposing alkali-soluble groups. With chemically amplified positive photoresist, after the protecting groups are removed, the acid is catalytically regenerated and can remove other protecting groups, making it possible to create positive patterns with high alkali solubility even with a small amount of light. This makes it possible to make the bottom of the film alkali-soluble, which was a challenge in creating thick films. However, the positive photosensitive resin composition using the m-cresol novolac phenolic resin described in Patent Document 1 still lacks sensitivity, and the problem of residual film remaining at the bottom of the pattern after development remains unresolved.

[0004] Therefore, chemically amplified positive-tone photosensitive resin compositions containing o-cresol and p-cresol in addition to m-cresol have also been investigated (for example, Patent Document 2). However, the photosensitive resin composition described in Patent Document 2 still has insufficient alkali solubility, and there are still problems such as the generation of a residual film at the bottom of the pattern after development, and low heat resistance. In addition, there are limitations to improving sensitivity due to low light transmittance at 365 nm, which is the wavelength of the i-line.

[0005] Furthermore, the development of a chemically amplified positive-type photosensitive resin composition using a hydroxyl-substituted aromatic aldehyde for the purpose of improving sensitivity has also been investigated (for example, Patent Document 3). However, although the positive-type photosensitive resin composition described in Patent Document 3 improves sensitivity, it has the problem of poor storage stability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-149816 [Patent Document 2] Japanese Patent Application Publication No. 2019-203097 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-300820 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a positive photosensitive resin composition which can give a resist film having high i-line transmittance, excellent developability and heat resistance, and which also has good storage stability. [Means for solving the problem]

[0008] As a result of intensive research to solve the above problems, the present inventors have found that a positive photosensitive resin composition containing a novolac phenolic resin having a specific structural unit and in which at least a portion of the phenolic hydroxyl groups are substituted with acetal group-based protecting groups, a photoacid generator, and a solvent has good storage stability and can produce a desired resist film, thereby completing the present invention.

[0009] That is, the present invention relates to a positive photosensitive resin composition containing the following components (A) to (C): (A) A novolak-type phenolic resin containing a phenol structural unit (a1) derived from m-cresol and / or o-cresol, an aldehyde structural unit (a2) derived from acetaldehyde, and an aldehyde structural unit (a3) ​​derived from salicylaldehyde, and having an acetal group-based protecting group. (B) Photoacid generator (C) Solvent

[0010] The present invention further relates to a photosensitive film obtained by drying the positive photosensitive resin composition. The present invention further relates to a resist film obtained from the positive photosensitive resin composition. The present invention further relates to a resist underlayer film obtained from the positive photosensitive resin composition. The present invention further relates to a permanent resist film obtained from the positive photosensitive resin composition. [Effects of the Invention]

[0011] According to the present invention, a positive photosensitive resin composition can be provided that can produce a resist film that has high i-line transmittance, excellent developability, and heat resistance, and also has good storage stability. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes the embodiments of the present invention. In this specification, "x to y" represents a numerical range of "not less than x and not more than y." The upper and lower limits of the numerical ranges can be combined in any way. Furthermore, a combination of two or more of the individual aspects of the present invention described below is also an aspect of the present invention.

[0013] [Positive-type photosensitive resin composition] A positive photosensitive resin composition according to one embodiment of the present invention contains the following components (A) to (C). (A) A novolak-type phenolic resin containing a phenol structural unit (a1) derived from m-cresol and / or o-cresol, an aldehyde structural unit (a2) derived from acetaldehyde, and an aldehyde structural unit (a3) ​​derived from salicylaldehyde, and having an acetal group-based protecting group. (B) Photoacid generator (C) Solvent

[0014] In this embodiment, the novolac phenolic resin has an acetal group-based protecting group, which produces a synergistic effect with the photoacid generator when the positive photosensitive resin composition is used as a resist film or the like. Specifically, the acetal group-based protecting group is eliminated from component (A) by the acid generated by the photoacid generator in the exposed area, whereas the acetal group-based protecting group is not eliminated from component (A) in the unexposed area. This results in a positive photosensitive resin composition that has excellent i-line transparency and, when formed into a resist film or the like, excellent developability, development contrast, and heat resistance. Furthermore, since the novolac phenolic resin contains the aldehyde structural unit (a2) derived from acetaldehyde, elimination of the acetal group-based protecting group over time is suppressed, and the storage stability of the positive photosensitive resin composition is improved.

[0015] Ingredient (A) The novolak phenolic resin, which is component (A), contains a phenol structural unit (a1) derived from m-cresol and / or o-cresol, an aldehyde structural unit (a2) derived from acetaldehyde, and an aldehyde structural unit (a3) ​​derived from salicylaldehyde, and has an acetal group-based protecting group.

[0016] The aldehyde structural unit (a3) ​​derived from salicylaldehyde can improve the alkali solubility of the novolac phenolic resin, which is the component (A).

[0017] The novolac phenolic resin as component (A) preferably has a molar ratio of phenol structural units (a1) derived from m-cresol, aldehyde structural units (a2) derived from acetaldehyde, and aldehyde structural units (a3) ​​derived from salicylaldehyde [(a1):(a2):(a3)] of 1.0:0.3-0.99:0.01-0.7.

[0018] The molar ratio of the phenol structural unit (a1) derived from m-cresol, the aldehyde structural unit (a2) derived from acetaldehyde, and the aldehyde structural unit (a3) ​​derived from salicylaldehyde contained in component (A) [(a1):(a2):(a3)] is preferably 1.0:0.4 to 0.98:0.02 to 0.6, and more preferably 1.0:0.5 to 0.95:0.05 to 0.5, from the viewpoint of obtaining a resist film or the like that has high developability and heat resistance.

[0019] Component (A) may contain structural units other than the phenol structural unit (a1) derived from m-cresol and / or o-cresol, the aldehyde structural unit (a2) derived from acetaldehyde, and the aldehyde structural unit (a3) ​​derived from salicylaldehyde. Examples of structural units other than (a1) to (a3) ​​include structural units derived from phenols or aldehydes other than m-cresol, o-cresol, acetaldehyde, and salicylaldehyde.

[0020] Examples of the phenols include phenol, p-cresol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, and 3,4,5-trimethylphenol.

[0021] Examples of the aldehydes include propionaldehyde, butanal, pentanal, hexanal, chloroacetaldehyde, benzaldehyde, 4-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 2-methoxybenzaldehyde, 3-nitrobenzaldehyde, phenylaldehyde, cinnamaldehyde, 1-naphthaldehyde, 2-naphthaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, and 4-biphenylaldehyde.

[0022] Regarding the above aldehydes, when the novolac phenolic resin as component (A) contains an aldehyde structural unit (a4) derived from formaldehyde, the content of the aldehyde structural unit (a4) derived from formaldehyde is preferably 10 mass % or less, more preferably 5 mass % or less, and even more preferably 3 mass % or less of the total amount of repeating units of the novolac phenolic resin. The novolak phenolic resin that is the component (A) preferably does not contain an aldehyde structural unit (a4) derived from formaldehyde.

[0023] Regarding the above aldehydes, the novolak type phenolic resin, which is component (A), preferably further contains an aldehyde structural unit (a5) derived from benzaldehyde. When the novolac phenolic resin as component (A) contains the aldehyde structural unit (a5) derived from benzaldehyde, the content of the aldehyde structural unit (a5) derived from benzaldehyde is preferably in the range of 5 to 50 mol % of the total amount of repeating units of the novolac phenolic resin, more preferably in the range of 5 to 30 mol %, and even more preferably in the range of 5 to 20 mol % of the total amount of repeating units of the novolac phenolic resin.

[0024] In the repeating units of the novolac phenolic resin, which is component (A), the total content of the structural units (a1), (a2), (a3) ​​and optional (a5) is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The total content of the structural units (a1), (a2), (a3) ​​and optional (a5) may be substantially 100% by mass, which also includes the unavoidable inclusion of structural units other than the structural units (a1), (a2), (a3) ​​and optional (a5).

[0025] The acetal group-based protecting group contained in component (A) is preferably a group represented by the following formula (1). [ka] (In the formula, R1 and R2 each independently represent a hydrogen atom, a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R3 is a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. R3 may be bonded to R1 or R2 to form a ring. * is bonded to the benzene ring that constitutes the main chain of the novolac phenolic resin.)

[0026] In component (A), at least a portion of the phenolic hydroxyl groups of the novolac phenolic resin are protected with an acetal group-based protecting group represented by the above formula (1). The acetal group-based protecting group can be removed by the acid generated from the photoacid generator. The fact that component (A) has an acetal group-based protecting group means that: 13 This can be confirmed by C-NMR.

[0027] In the formula (1), examples of the linear alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Examples of the branched alkyl group having 3 to 20 carbon atoms include an isopropyl group, a sec-butyl group, a tert-butyl group, a neopentyl group, an isopentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 2,3-dimethylbutyl group. Examples of the cyclic alkyl group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, etc. The cyclic alkyl group may have a substituent such as the linear alkyl group described above. Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a naphthyl group, an anthracenyl group, etc. The aryl group may have a substituent such as the alkyl group described above.

[0028] Aralkyl groups are alkyl groups (C n H 2n+1 ) means an alkyl group in which one or more hydrogen atoms are substituted with an aryl group. The aryl group may have a substituent such as the alkyl group described above. Specific examples include a phenylmethyl group, a tolylmethyl group, a xylylmethyl group, a naphthylmethyl group, a hydroxynaphthylmethyl group, a dihydroxynaphthylmethyl group, a phenylethyl group, a hydroxyphenylethyl group, a dihydroxyphenylethyl group, a tolylethyl group, a xylylethyl group, a naphthylethyl group, a hydroxynaphthylethyl group, and a dihydroxynaphthylethyl group. The number of carbon atoms is preferably 7 to 15, for example.

[0029] R3 may combine with R1 or R2 to form a ring, examples of which include oxygen-containing heterocycles such as a furan ring and a pyran ring.

[0030] Specific examples of the acetal group-based protecting group represented by the above formula (1) include a 1-methoxyethoxy group, a 1-ethoxyethoxy group, a 1-propoxyethoxy group, a 1-butoxyethoxy group, a 2-methoxypropoxy group, a 2-ethoxypropoxy group, a 1-(2-methylpropoxy)ethoxy group, a 1-(1-propoxy)propoxy group, a 1-ethoxybutoxy group, a 1-(2-methoxyethoxy)ethoxy group, a 1-(2-acetoxyethoxy)ethoxy group, a tetrahydrofuran-2-yl group, a 1-[(1-adamantyloxy)ethoxy]ethyl group, a 1-[2-(1-adamantanecarbonyloxy)ethoxy]ethyl group, a tetrahydro-2-pyranyl group, a tetrahydro-2-furyl group, a 1-(cyclohexyloxy)ethoxy ... oxy group, 1-phenoxyethoxy group, 1-(2-cyclohexyl)ethoxyethoxy group, (1-adamantyloxy)ethoxy group, (2-adamantyloxy)ethoxy group, (1-adamantylmethoxy)ethoxy group, (2-adamantylethoxy)ethoxy group, 1-(1-bicyclo[2.2.1]heptyloxy)ethoxy group, 1-(2-bicyclo[2.2.1]heptyloxy)ethoxy group, 1-(1-bicyclo[2.2.1]heptylmethoxy)ethoxy group, 1-(2-bicyclo[2.2.1]heptylmethoxy)ethoxy group, 2-(1,7,7-trimethylbicyclo[2.2.1]heptyloxy)ethoxy group, 2-(1-isopropyl-4-methylcyclohexyloxy)ethoxy group, and the like. The protecting group represented by the above formula (1) is preferably a 1-propoxyethoxy group.

[0031] The acetal group-based protecting group is not limited to those represented by the above formula (1), and may be, for example, a group derived from a compound that forms a crosslinkable protecting group, which will be described later.

[0032] The protection rate of phenolic hydroxyl groups in the novolac phenolic resin in component (A) (the ratio of bonds of acetal group-based protecting groups to the total number of phenolic hydroxyl groups in the novolac phenolic resin) is 1 to 50 mol %, preferably 2 to 40 mol %, more preferably 5 to 25 mol %, and even more preferably 7.5 to 15 mol %, from the viewpoint of ensuring an appropriate dissolution rate in an alkaline developer.

[0033] The weight-average molecular weight of the novolac phenolic resin, component (A), is preferably 1,000 or more, more preferably 1,500 or more. It is also preferably 10,000 or less, more preferably 6,000 or less, and even more preferably 3,000 or less. A weight-average molecular weight of 1,000 or more is preferred because it provides high heat resistance. On the other hand, a weight-average molecular weight of 10,000 or less is preferred because it provides high sensitivity. In this specification, the weight-average molecular weight is measured according to the conditions described in the Examples.

[0034] Component (A) is preferably obtained by polycondensing m-cresol and / or o-cresol, acetaldehyde, and salicylaldehyde in an organic solvent using an acid catalyst in a molar ratio (m-cresol and / or o-cresol:acetaldehyde:salicylaldehyde) of 1.0:0.3 to 0.99:0.01 to 0.7 to obtain a novolak phenolic resin (a), and then reacting the resulting resin with a compound that forms an acetal group-based protecting group. The synthesis of the novolac phenolic resin (a) and the introduction of an acetal group-based protecting group will be described below.

[0035] (Synthesis of novolac-type phenolic resin (a)) The novolac type phenolic resin (a) can be obtained, for example, by dissolving raw material compounds in a reaction solvent and carrying out a synthesis reaction using an acid catalyst according to a conventional method.

[0036] Examples of reaction solvents used in producing the novolac phenolic resin (a) include methanol, ethanol, 1-propanol, 2-propanol, butanol, hexanol, ethylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, methyl ethyl ketone, methyl isobutyl ketone, and toluene. Among these, one or more selected from ethanol, 1-propanol, and 2-propanol are preferred, and ethanol or methyl isobutyl ketone is more preferred.

[0037] The molar ratio of m-cresol and / or o-cresol, acetaldehyde, and salicylaldehyde in the reaction solvent (m-cresol and / or o-cresol:acetaldehyde:salicylaldehyde) is preferably 1.0:0.4-0.98:0.02-0.6, and more preferably 1.0:0.5-0.95:0.05-0.5, from the viewpoint of obtaining a resist film or the like that not only has high sensitivity but also exhibits low-temperature curing and chemical resistance.

[0038] In the novolak phenolic resin (a), the monomers (starting compounds) constituting the phenol structural unit (a1) derived from m-cresol, the aldehyde structural unit (a2) derived from acetaldehyde, and the aldehyde structural unit (a3) ​​derived from salicylaldehyde are not limited to m-cresol, o-cresol, acetaldehyde, and salicylaldehyde. For example, paraldehyde (acetaldehyde trimer) may be used as the compound constituting the aldehyde structural unit (a2) derived from acetaldehyde.

[0039] When m-cresol and / or o-cresol, acetaldehyde, and salicylaldehyde are polycondensed in an organic solvent to obtain the novolak phenolic resin (a), the organic solvent may contain phenols and aldehydes other than m-cresol, o-cresol, acetaldehyde, and salicylaldehyde, as described above. As the other aldehydes, benzaldehyde is preferred.

[0040] In order to obtain a resist film that not only has high sensitivity but also exhibits heat resistance upon low-temperature curing, the proportion by total mass of m-cresol and / or o-cresol, acetaldehyde, salicylaldehyde, and optional benzaldehyde in the reaction solvent relative to the total mass of all starting materials that can become structural units constituting component (A) is preferably 50 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more, in that order, and more preferably substantially 100 mass%.

[0041] From the viewpoint of uniformity of the reaction, the amount of the reaction solvent used is preferably 20 parts by mass or more, more preferably 50 parts by mass or more, per 100 parts by mass of the raw materials from which the structural units constituting component (A) are derived, and is preferably 500 parts by mass or less, more preferably 300 parts by mass or less.

[0042] Examples of the acid catalyst used in producing the novolac phenolic resin (a) include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and boric acid, and organic acids such as oxalic acid, acetic acid, and paratoluenesulfonic acid. Among these, inorganic acids and paratoluenesulfonic acid are preferred, and paratoluenesulfonic acid is more preferred, in order to further promote the reaction. The amount of acid catalyst added is not particularly limited, but is preferably at least 5 parts by mass, more preferably at least 20 parts by mass, per 100 parts by mass of the raw materials from which the structural units constituting component (A) are derived, and is preferably at most 150 parts by mass, more preferably at most 100 parts by mass.

[0043] The reaction temperature during polycondensation of the raw materials for the novolac phenolic resin (a) is preferably 30° C. or higher, more preferably 40° C. or higher, in order to promote the reaction and efficiently increase the molecular weight, and is preferably 100° C. or lower, more preferably 80° C. or lower. The reaction time is preferably 4 hours or more, more preferably 12 hours or more, and is preferably 32 hours or less, more preferably 24 hours or less.

[0044] (Introduction of an acetal-based protecting group) The method for introducing the acetal group-based protecting group is not particularly limited, and examples thereof include a method in which the novolak resin (a) and a compound that forms an acetal group-based protecting group are added to a reaction solvent and reacted using an acid catalyst. The acetal group-based protecting group is generated by reacting the phenolic hydroxyl group in the novolac phenolic resin (a) with a compound that forms an acetal group-based protecting group in an acid catalyst, and protects the phenolic hydroxyl group in the novolac phenolic resin (a).

[0045] The reaction solvent used in the synthesis of the novolak phenolic resin (a) can be suitably used as the reaction solvent for introducing the acetal group-based protecting group. Methyl isobutyl ketone is preferred as the reaction solvent for introducing the acetal group-based protecting group.

[0046] The acid catalyst used in the introduction of the acetal group-based protecting group can be the same as that used in the synthesis of the novolak phenolic resin (a). Among these, inorganic acids and paratoluenesulfonic acid are preferred, and paratoluenesulfonic acid is more preferred, in order to further promote the reaction.

[0047] When introducing an acetal-based protecting group, the reaction time is preferably 1 hour or longer, more preferably 2 hours or longer, and preferably 10 hours or shorter, more preferably 6 hours or shorter. When introducing an acetal group-based protecting group, the reaction temperature can be the same as that used in the synthesis of the novolak-type phenolic resin (a) above.

[0048] In this embodiment, the compound that forms an acetal group-based protecting group is preferably a compound represented by the following formula (2). [ka] (In the formula, R3 is a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. R4 to R6 are each independently a hydrogen atom, a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0049] In formula (2), specific examples of the linear alkyl group having 1 to 20 carbon atoms, the branched alkyl group having 3 to 20 carbon atoms, the cyclic alkyl group having 3 to 20 carbon atoms, the aryl group having 6 to 20 carbon atoms, and the aralkyl group having 7 to 20 carbon atoms are the same as those in formula (1) above. Any two of R3, R4, R5 and R6 may be bonded to form a ring, for example, R3 and R6 may be bonded to form a cyclic ether.

[0050] Examples of compounds that form the acetal group-based protecting group represented by the above formula (2) include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, phenyl vinyl ether, benzyl vinyl ether, phenethyl vinyl ether, menthyl vinyl ether, 1-adamantyl vinyl ether, 2-adamantyl vinyl ether, [(adamantan-1-yl)methyl] vinyl ether, [(adamantan-1-yl)methyl] vinyl ether, Examples of vinyl ether include vinyl ether, vinyl ether (vinyloxymethyl) damantan-2-yl), ...ethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2-yl), vinyl ether (vinyloxyethyl) damantan-2

[0051] In the present embodiment, the compound represented by the formula (2) is preferably blended in an amount of 1 part by mass or more, more preferably 5 parts by mass or more, relative to 100 parts by mass of the novolac phenolic resin (a), since good developability (sensitivity) and development contrast can be obtained, and is preferably blended in an amount of 20 parts by mass or less, more preferably 15 parts by mass or less.

[0052] Compounds other than the compound represented by formula (2) may be used as compounds that form acetal group-based protecting groups. For example, compounds that form crosslinkable protecting groups can be used. Examples of compounds that form crosslinkable protecting groups include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,3-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, trimethylolethane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, and cyclohexanedimethanol divinyl ether.

[0053] ·Component (B) The photoacid generator, component (B), is a compound that generates an acid by bond cleavage upon exposure. By incorporating a photoacid generator, the acetal group-based protecting group is cleaved from component (A) in the exposed area due to the acid generated by the photoacid generator. This reaction exposes the phenolic hydroxyl groups of the novolac phenolic resin, creating a difference in alkali solubility between the unexposed and exposed areas. This improves the developability (sensitivity) and development contrast when the positive photosensitive resin composition is used to form a resist film.

[0054] The photoacid generator is not particularly limited, and known photoacid generators can be used, such as organic halogen compounds, sulfonate esters, onium salts (phosphonium salts, sulfonium salts, iodonium salts, etc.), diazonium salts, diazomethane compounds, nitrobenzyl compounds, disulfone compounds, and triazine-based photoacid generators. In one embodiment, the photoacid generator is not a naphthoquinone diazide compound.

[0055] Specific examples of the photoacid generator include the following. haloalkyl group-containing s-triazine derivatives such as tris(trichloromethyl)-s-triazine, tris(tribromomethyl)-s-triazine, tris(dibromomethyl)-s-triazine, 2,4-bis(tribromomethyl)-6-p-methoxyphenyl-s-triazine, and (2-[2-(5-methylfuran-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine);

[0056] Halogen-substituted paraffin hydrocarbon compounds such as 1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon tetrabromide, and iodoform; halogen-substituted cycloparaffin hydrocarbon compounds such as hexabromocyclohexane, hexachlorocyclohexane, and hexabromocyclododecane;

[0057] Benzene derivatives containing haloalkyl groups, such as bis(trichloromethyl)benzene and bis(tribromomethyl)benzene; sulfone compounds containing haloalkyl groups, such as tribromomethyl phenyl sulfone and trichloromethyl phenyl sulfone; halogen-containing sulfolane compounds, such as 2,3-dibromosulfolane; isocyanurate compounds containing haloalkyl groups, such as tris(2,3-dibromopropyl)isocyanurate;

[0058] sulfonium salts such as triphenylsulfonium chloride, diphenyl-4-methylphenylsulfonium trifluoromethanesulfonate, diphenyl[4-(phenylthio)phenyl]sulfonium trifluoromethanesulfonate, triphenylsulfonium methanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate, and triphenylsulfonium hexafluorophosphonate;

[0059] iodonium salts such as diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroarsenate, and diphenyliodonium hexafluorophosphonate;

[0060] Methyl p-toluenesulfonate, Ethyl p-toluenesulfonate, p-toluenesulfonate sulfonate compounds such as butyl methanesulfonate, phenyl p-toluenesulfonate, 1,2,3-tris(p-toluenesulfonyloxy)benzene, p-toluenesulfonic acid benzoin ester, methyl methanesulfonate, ethyl methanesulfonate, butyl methanesulfonate, 1,2,3-tris(methanesulfonyloxy)benzene, phenyl methanesulfonate, methanesulfonic acid benzoin ester, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, butyl trifluoromethanesulfonate, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, phenyl trifluoromethanesulfonate, and trifluoromethanesulfonic acid benzoin ester; disulfone compounds such as diphenyl disulfone;

[0061] Bis(phenylsulfonyl)diazomethane, bis(2,4-dimethylphenylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, cyclohexylsulfonyl-(2-methoxyphenylsulfonyl)diazomethane, cyclohexylsulfonyl-(3-methoxyphenylsulfonyl)diazomethane, cyclohexylsulfonyl-(4-methoxyphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(2-methoxyphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(3-methoxyphenylsulfonyl) phenyl)diazomethane, cyclopentylsulfonyl-(4-methoxyphenylsulfonyl)diazomethane, cyclohexylsulfonyl-(2-fluorophenylsulfonyl)diazomethane, cyclohexylsulfonyl-(3-fluorophenylsulfonyl)diazomethane, cyclohexylsulfonyl-(4-fluorophenylsulfonyl)diazomethane, cyclopentylsulfonyl-(2-fluorophenylsulfonyl)diazomethane, cyclopentylsulfonyl-(3-fluorophenylsulfonyl)diazomethane, cyclopentylsulfonyl- (4-Fluorophenylsulfonyl)diazomethane, cyclohexylsulfonyl-(2-chlorophenylsulfonyl)diazomethane, cyclohexylsulfonyl-(3-chlorophenylsulfonyl)diazomethane, cyclohexylsulfonyl-(4-chlorophenylsulfonyl)diazomethane, cyclopentylsulfonyl-(2-chlorophenylsulfonyl)diazomethane, cyclopentylsulfonyl-(3-chlorophenylsulfonyl)diazomethane, cyclopentylsulfonyl-(4-chlorophenylsulfonyl)diazomethane, cyclohexyl cyclohexylsulfonyl-(2-trifluoromethylphenylsulfonyl)diazomethane, cyclohexylsulfonyl-(3-trifluoromethylphenylsulfonyl)diazomethane, cyclohexylsulfonyl-(4-trifluoromethylphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(2-trifluoromethylphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(3-trifluoromethylphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(4-trifluoromethylphenylsulfonyl)diazomethane,Cyclohexylsulfonyl-(2-trifluoromethoxyphenylsulfonyl)diazomethane, cyclohexylsulfonyl-(3-trifluoromethoxyphenylsulfonyl)diazomethane, cyclohexylsulfonyl-(4-trifluoromethoxyphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(2-trifluoromethoxyphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(3-trifluoromethoxyphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(4-trifluoromethoxyphenyl) Cyclohexylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane, Cyclohexylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane, Cyclohexylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane, Cyclohexylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane, Cyclopentylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane, Cyclopentylsulfonyl-(2,3,4- (trimethylphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane, cyclopentylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane, phenylsulfonyl-(2-methoxyphenylsulfonyl)diazomethane, phenylsulfonyl-(3-methoxyphenylsulfonyl)diazomethane, phenylsulfonyl-(4-methoxyphenylsulfonyl)diazomethane, bis(2-methoxyphenylsulfonyl)diazomethane, bis(3-methoxyphenylsulfonyl) phenylsulfonyl)diazomethane, bis(4-methoxyphenylsulfonyl)diazomethane, phenylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane, phenylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane, phenylsulfonyl-(2,4,6-triethylphenylsulfonyl)diazomethane, phenylsulfonyl-(2,3,4-triethylphenylsulfonyl)diazomethane, 2,4-dimethylphenylsulfonyl-(2,4,6-trimethylphenylsulfonyl)diazomethane,Sulfone diazide compounds such as 2,4-dimethylphenylsulfonyl-(2,3,4-trimethylphenylsulfonyl)diazomethane, phenylsulfonyl-(2-fluorophenylsulfonyl)diazomethane, phenylsulfonyl-(3-fluorophenylsulfonyl)diazomethane, and phenylsulfonyl-(4-fluorophenylsulfonyl)diazomethane;

[0062] o-Nitrobenzyl ester compounds such as o-nitrobenzyl-p-toluenesulfonate; sulfonhydrazide compounds such as N,N'-di(phenylsulfonyl)hydrazide; sulfonium salts, which are salts of sulfonium cations such as triarylsulfonium and triaralkylsulfonium with sulfonates such as fluoroalkanesulfonates, arenesulfonates and alkanesulfonates;

[0063] iodonium salts, which are salts of iodonium cations such as diaryliodonium and sulfonates such as fluoroalkanesulfonates, arenesulfonates, and alkanesulfonates; bissulfonyldiazomethane compounds such as bis(alkylsulfonyl)diazomethane, bis(cycloalkylsulfonyl)diazomethane, bis(perfluoroalkylsulfonyl)diazomethane, bis(arylsulfonyl)diazomethane, and bis(aralkylsulfonyl)diazomethane;

[0064] N-sulfonyloxyimide compounds comprising a combination of a dicarboxylic acid imide compound and a sulfonate such as a fluoroalkanesulfonate, an arenesulfonate, or an alkanesulfonate; benzoin sulfonate compounds such as benzoin tosylate, benzoin mesylate, and benzoin butanesulfonate; Polyhydroxyarene sulfonate compounds in which all of the hydroxy groups of a polyhydroxyarene compound have been substituted with sulfonates such as fluoroalkanesulfonates, arenesulfonates, and alkanesulfonates;

[0065] Nitrobenzyl sulfonate compounds such as (poly)nitrobenzyl fluoroalkanesulfonate, (poly)nitrobenzyl arenesulfonate, and (poly)nitrobenzyl alkanesulfonate; Fluoroalkanebenzyl sulfonate compounds such as (poly)fluoroalkanebenzyl fluoroalkanesulfonate, (poly)fluoroalkanebenzyl arenesulfonate, and (poly)fluoroalkanebenzyl alkanesulfonate;

[0066] Bis(arylsulfonyl)alkane compounds; bis-O-(arylsulfonyl)-α-dialkylglyoximes, bis-O-(arylsulfonyl)-α-dicycloalkylglyoximes, bis-O-(arylsulfonyl)-α-diarylglyoximes, bis-O-(alkylsulfonyl)-α-dialkylglyoximes, bis-O-(alkylsulfonyl)-α-dicycloalkylglyoximes, bis-O-(alkylsulfonyl)-α-diarylglyoximes, bis-O-(fluoroalkylsulfonyl)-α-dialkylglyoximes, bis-O-(fluoroalkylsulfonyl)-α-dicycloalkylglyoximes, bis-O-(fluoroalkylsulfonyl)-α-diarylglyoximes, oxime compounds such as bis-O-(arylsulfonyl)-α-dialkyldioximes, bis-O-(arylsulfonyl)-α-dicycloalkyldioximes, bis-O-(arylsulfonyl)-α-diaryldioximes, bis-O-(alkylsulfonyl)-α-dialkyldioximes, bis-O-(alkylsulfonyl)-α-dicycloalkyldioximes, bis-O-(alkylsulfonyl)-α-diaryldioximes, bis-O-(fluoroalkylsulfonyl)-α-dialkyldioximes, bis-O-(fluoroalkylsulfonyl)-α-dicycloalkyldioximes, and bis-O-(fluoroalkylsulfonyl)-α-diaryldioximes;

[0067] Modified oxime compounds such as arylsulfonyloxyiminoarylacetonitrile, alkylsulfonyloxyiminoarylacetonitrile, fluoroalkylsulfonyloxyiminoarylacetonitrile, ((arylsulfonyl)oxyimino-thiophen-ylidene)arylacetonitrile, ((alkylsulfonyl)oxyimino-thiophen-ylidene)arylacetonitrile, ((fluoroalkylsulfonyl)oxyimino-thiophen-ylidene)arylacetonitrile, bis(arylsulfonyloxyimino)arylenediacetonitrile, bis(alkylsulfonyloxyimino)arylenediacetonitrile, bis(fluoroalkylsulfonyloxyimino)arylenediacetonitrile, arylfluoroalkanone-O-(alkylsulfonyl)oxime, arylfluoroalkanone-O-(arylsulfonyl)oxime, and arylfluoroalkanone-O-(fluoroalkylsulfonyl)oxime.

[0068] The photoacid generator may be used alone or in combination of two or more kinds. The amount of the photoacid generator to be added is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, relative to 100 parts by mass of component (A), from the viewpoints of ensuring good i-line transmittance of the positive photosensitive resin composition and obtaining good developability (sensitivity) and heat resistance when the positive photosensitive resin composition is formed into a resist film, etc. Also, the amount is preferably 20 parts by mass or less, more preferably 5 parts by mass or less.

[0069] ·Component (C) Examples of the solvent as component (C) include polar aprotic solvents such as N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, propylene glycol monomethyl ether, and propylene glycol monoethyl ether, ketones such as acetone, methyl ethyl ketone, and diisobutyl ketone, esters such as ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, propylene glycol monomethyl ether acetate, and 3-methyl-3-methoxybutyl acetate, alcohols such as ethyl lactate, methyl lactate, diacetone alcohol, and 3-methyl-3-methoxybutanol, and aromatic hydrocarbons such as toluene and xylene. These solvents may be used alone or in combination of two or more.

[0070] The amount of solvent blended in the positive photosensitive resin composition of this embodiment is such that the solids concentration in the composition is preferably 5% by mass or more, and more preferably 65% ​​by mass or less, because the fluidity of the composition allows a uniform coating film to be obtained by a coating method such as spin coating.

[0071] Other ingredients In one embodiment, the positive photosensitive resin composition may contain various additives in addition to the above-described components (A) to (C) within the range that does not impair the effects of the present invention. Examples of additives include fillers, pigments, surfactants such as leveling agents, adhesion improvers, and dissolution promoters.

[0072] The positive photosensitive resin composition of this embodiment can be prepared by stirring and mixing the above-mentioned components (A) to (C), and various additives as needed, in a conventional manner to form a homogeneous liquid. When solid materials such as fillers and pigments are blended into the composition, they are preferably dispersed and mixed using a dispersing device such as a dissolver, homogenizer, triple roll mill, etc. The composition can also be filtered using a mesh filter, membrane filter, etc. to remove coarse particles and impurities.

[0073] The positive photosensitive resin composition of this embodiment can be suitably used for applications such as resist films, resist underlayer films, and permanent resist films.

[0074] The positive photosensitive resin composition of the present invention can be used in the same manner as a general positive photosensitive resin composition to form a resist film, a resist underlayer film, and a permanent resist film (hereinafter, the resist film, the resist underlayer film, and the permanent resist film may be collectively referred to as a resist film, etc.). Specifically, the positive photosensitive resin composition of the present invention is applied to an object to be subjected to photolithography, and then prebaked to obtain a film of the photosensitive resin composition (photosensitive film) from which the solvent has been removed.

[0075] Examples of application methods include spin coating, roll coating, flow coating, dip coating, spray coating, and doctor blade coating. Pre-baking may involve heating at a temperature of 60°C to 150°C for 30 to 600 seconds. The positive photosensitive resin composition of the present invention can be applied to a substrate appropriately selected from glass substrates, silicon substrates, aluminum substrates, silicon carbide substrates, silicon nitride substrates, gallium nitride substrates, transparent conductive films, copper substrates, copper-plated substrates, and the like.

[0076] Exposure of the photosensitive film to an acid generates a catalytic reaction, which causes an elimination reaction of the acetal group-based protecting group from component (A), significantly increasing the solubility of the exposed area in an alkaline developer. Examples of light sources used for exposure include infrared light, visible light, ultraviolet light, far-ultraviolet light, X-rays, and electron beams. Among these light sources, ultraviolet light is preferred, and the g-line (wavelength 436 nm) and i-line (wavelength 365 nm) of a high-pressure mercury lamp are suitable. After exposure, the film may be subjected to a heat treatment at about 100°C to 150°C in order to promote the elimination reaction of the acetal group-based protecting group from component (A).

[0077] The photosensitive film obtained from the positive photosensitive resin composition of the present invention has high alkali solubility in the exposed area and a large difference in alkali solubility between the exposed area and the unexposed area, allowing for high-resolution patterning. Therefore, the composition can be suitably used as a resist film, etc. In this application, the term "resist film, etc." includes both a photosensitive film before exposure and a non-photosensitive film after exposure.

[0078] Examples of alkaline developers used for development after exposure include alkaline aqueous solutions of inorganic alkaline substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldiethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; and cyclic amines such as pyrrole and piheridine. The alkaline developer may be used by adding alcohol, surfactant, etc. as needed. The alkaline concentration of the alkaline developer is usually preferably in the range of 2 to 5% by mass, and a 2.38% by mass aqueous solution of tetramethylammonium hydroxide is generally used.

[0079] When the positive photosensitive resin composition of the present invention is used for a resist underlayer film (BARC film), the positive photosensitive resin composition of the present invention may be used as it is as a composition for a resist underlayer film, or various additives such as other resin components, surfactants, dyes, fillers, crosslinking agents, and dissolution promoters may be added, if necessary.

[0080] Examples of other resin components include various novolak resins, addition polymerization resins of alicyclic diene compounds such as dicyclopentadiene and phenolic compounds, modified novolak resins of phenolic hydroxyl group-containing compounds and alkoxy group-containing aromatic compounds, phenol aralkyl resins (Zylok resins), naphthol aralkyl resins, trimethylolmethane resins, tetraphenylolethane resins, biphenyl-modified phenolic resins, biphenyl-modified naphthol resins, aminotriazine-modified phenolic resins, and various vinyl polymers. When other resin components are used, the blending ratio of the positive photosensitive resin composition of the present invention to the other resins can be set as desired depending on the application. For example, the blending ratio is preferably 0.5 to 100 parts by mass of the other resins per 100 parts by mass of component (A).

[0081] The composition for a resist underlayer film can be prepared by blending the above-mentioned components and mixing them using a stirrer, etc. Furthermore, when the composition for a resist underlayer film contains a filler or a pigment, it can be prepared by dispersing or mixing using a dispersing device such as a dissolver, a homogenizer, or a three-roll mill.

[0082] To form a resist underlayer film from the resist underlayer film composition, for example, the above-described resist underlayer film composition is applied to an object to be photolithographed, such as a silicon substrate, dried at a temperature of 100 to 200° C., and then further cured by heating at a temperature of 250 to 400° C. Next, a resist pattern is formed on this underlayer film by performing a normal photolithography operation, and a dry etching treatment is performed with a halogen-based plasma gas or the like, thereby forming a resist pattern by a multilayer resist method.

[0083] When the positive photosensitive resin composition of the present invention is used for a permanent resist film, in addition to the components (A) to (C) of the present invention, additives such as other resins, surfactants, dyes, fillers, crosslinking agents, dissolution promoters, etc. Examples of other resins used here include the same resins that can be used in compositions for resist underlayer films.

[0084] In a photolithography method using a composition for a permanent resist film, for example, other resin components and additive components are dissolved or dispersed in the positive photosensitive resin composition of the present invention, and the composition is applied to an object to be photolithographed, followed by pre-baking at a temperature of 60 to 150° C. The application method may be any of spin coating, roll coating, flow coating, dip coating, spray coating, doctor blade coating, etc. Next, the desired resist pattern is exposed through a predetermined mask, and the exposed areas are dissolved in an alkaline developer to form a resist pattern.

[0085] The permanent resist film of this embodiment can be suitably used, for example, in semiconductor devices, as solder resist, packaging material, underfill material, package adhesive layer for circuit elements, and adhesive layer between integrated circuit elements and circuit boards, and in thin-film displays such as LCDs and OLEDs, as thin-film transistor protective films, liquid crystal color filter protective films, black matrices, spacers, and the like. [Example]

[0086] The present invention will be described in more detail below with reference to specific examples. The weight average molecular weight (Mw) of the synthesized resin was measured under the following GPC measurement conditions. [GPC measurement conditions] Measuring device: Tosoh Corporation "HLC-8220 GPC" Column: Showa Denko K.K. "Shodex KF802": 8.0mmΦ x 300mm +Showa Denko KF802: 8.0mmΦ x 300mm +Showa Denko KF803: 8.0mmΦ x 300mm +Showa Denko KF804: 8.0mmΦ x 300mm Column temperature: 40℃ Detector: RI (differential refractometer) Data processing: Tosoh Corporation "GPC-8020 Model II Version 4.30" Developing solvent: tetrahydrofuran Flow rate: 1.0mL / min Sample: 0.5% by mass of tetrahydrofuran solution converted to resin solids filtered through a microfilter Injection volume: 0.1mL Standard sample: monodisperse polystyrene as follows (Standard sample: monodisperse polystyrene) Tosoh Corporation "A-500" Tosoh Corporation "A-2500" Tosoh Corporation "A-5000" "F-1" manufactured by Tosoh Corporation "F-2" manufactured by Tosoh Corporation "F-4" manufactured by Tosoh Corporation "F-10" manufactured by Tosoh Corporation "F-20" manufactured by Tosoh Corporation

[0087] Synthesis Example 1 (Synthesis of Novolak-Type Phenol Resin (A-1) Having Acetal Group-Based Protecting Group) A 2000ml four-neck flask equipped with a condenser was charged with 164g (1.52mol) of m-cresol, 40g (0.30mol) of paraaldehyde, 73g (0.60mol) of salicylaldehyde, and 8g of paratoluenesulfonic acid, which were then dissolved in 300g of ethanol as the reaction solvent. The mixture was heated in a mantle heater and stirred at 80°C under reflux for 16 hours to allow the reaction to proceed. After the reaction, ethyl acetate and water were added and the mixture was washed five times with separation. The solvent was removed from the remaining resin solution by distillation under reduced pressure, and the resulting mixture was then vacuum dried, yielding 243g of a pale red novolac phenolic resin powder (a-1). Next, 80 g of novolac-type phenolic resin powder (a-1), 12 g of propyl vinyl ether, and 0.1 g of paratoluenesulfonic acid were placed in a 500 ml four-neck flask and dissolved in 120 g of methyl isobutyl ketone as a reaction solvent. The mixture was heated using a mantle heater and stirred at 40°C for 4 hours to allow the reaction to proceed. After the reaction, 0.4 g of dimethylaminoethanol was added, and the mixture was thoroughly stirred. Five separate washings were performed using ethyl acetate and water. The solvent was removed from the remaining resin solution by distillation under reduced pressure, followed by vacuum drying, yielding 55 g of pale red novolac-type phenolic resin powder (A-1). 13 C-NMR confirmed that the novolak phenolic resin (A-1) had an acetal-based protecting group. The weight-average molecular weight (Mw) of the novolak phenolic resin (A-1) was 2,430.

[0088] Synthesis Example 2 (Synthesis of Novolak-Type Phenol Resin (A-2) Having Acetal Group-Based Protecting Group) Except for changing the amounts of starting materials to 164 g (1.52 mol) of m-cresol, 46 g (0.35 mol) of paraldehyde, and 55 g (0.45 mol) of salicylic aldehyde, 56 g of novolac phenolic resin powder (A-2) was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac phenolic resin (A-2) was 2,420.

[0089] Synthesis Example 3 (Synthesis of Novolak-Type Phenol Resin (A-3) Having Acetal Group-Based Protecting Group) Except for changing the amounts of starting materials to 164 g (1.52 mol) of m-cresol, 53 g (0.40 mol) of paraldehyde, and 37 g (0.30 mol) of salicylaldehyde, 58 g of novolac phenolic resin powder (A-3) was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac phenolic resin (A-3) was 2,380.

[0090] Synthesis Example 4 (Synthesis of Novolak-Type Phenol Resin (A-4) Having Acetal Group-Based Protecting Group) Except for changing the amounts of starting materials to 164 g (1.52 mol) of m-cresol, 60 g (0.45 mol) of paraldehyde, and 18 g (0.15 mol) of salicylaldehyde, 56 g of a novolac phenolic resin powder (A-4) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac phenolic resin (A-4) was 2,330.

[0091] Synthesis Example 5 (Synthesis of Novolak-Type Phenol Resin (A-5) Having Acetal Group-Based Protecting Groups) Except for changing the amounts of starting materials to 164 g (1.52 mol) of m-cresol, 20 g (0.15 mol) of paraldehyde, and 128 g (1.05 mol) of salicylaldehyde, 55 g of a novolac phenolic resin powder (A-5) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac phenolic resin (A-5) was 2,480.

[0092] Synthesis Example 6 (Synthesis of Novolak-Type Phenol Resin (A-6) Having Acetal Group-Based Protecting Group) Except for using o-cresol instead of m-cresol, 59 g of a novolak phenolic resin powder (A-6) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolak phenolic resin (A-6) was 2,320.

[0093] Synthesis Example 7 (Synthesis of Novolak-Type Phenol Resin (A-7) Having Acetal Group-Based Protecting Groups) 80 g of the novolac phenolic resin powder (a-1) obtained in Synthesis Example 1 was dissolved in 120 g of methyl isobutyl ketone. The mixture was heated to 100°C with stirring using a mantle heater. 6 g of cyclohexanedimethanol divinyl ether was then added, and the mixture was allowed to react for 24 hours. After the reaction, the methyl isobutyl ketone was distilled off under reduced pressure, followed by vacuum drying to obtain 82 g of a pale red powder of novolac phenolic resin (A-7). The Mw of the novolac phenolic resin (A-7) was 9,140.

[0094] Synthesis Example 8 (Synthesis of Novolak-Type Phenol Resin (A-8) Having Acetal Group-Based Protecting Group) Except for changing the amounts of starting materials to 164 g (1.52 mol) of m-cresol, 20 g (0.15 mol) of paraldehyde, 73 g (0.60 mol) of salicylaldehyde, and 48 g (0.45 mol) of benzaldehyde, 58 g of a novolac phenolic resin powder (A-8) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac phenolic resin (A-8) was 2,650.

[0095] Comparative Synthesis Example 1 (Synthesis of Novolak-Type Phenol Resin (A-9) Having Acetal Group-Based Protecting Groups) Under a dry nitrogen stream, a 2000 ml four-neck flask equipped with a condenser was charged with 140 g (1.30 mol) of m-cresol, 76 g (0.7 mol) of p-cresol, 151 g of 37 wt % formaldehyde aqueous solution (1.86 mol of formaldehyde), and 1 g (0.01 mol) of oxalic acid dihydrate, which were then dissolved in 528 g of methyl isobutyl ketone. The mixture was heated with a mantle heater and stirred under reflux for 4 hours. After the reaction, water was added and the mixture was washed five times with separation. The methyl isobutyl ketone was removed under reduced pressure at 60°C using an evaporator, and the mixture was then dried in vacuo to obtain 212 g of a pale red powder of novolac-type phenolic resin (a-9). Next, 80 g of the obtained novolac-type phenolic resin powder (a-9), 8 g of ethyl vinyl ether, and 0.1 g of paratoluenesulfonic acid were placed in a 500 ml four-neck flask and dissolved in 120 g of methyl isobutyl ketone as a reaction solvent. The mixture was heated using a mantle heater and stirred at 40°C for 4 hours to allow the reaction to proceed. After the reaction, 0.4 g of dimethylaminoethanol was added, and the mixture was thoroughly stirred. Then, ethyl acetate and water were added and the mixture was washed five times by separation. The solvent was removed from the remaining resin solution by distillation under reduced pressure, and the mixture was then vacuum-dried to obtain 58 g of a pale red powder of novolac-type phenolic resin powder (A-9). The Mw of the novolac phenolic resin (A-9) was 3,600.

[0096] Comparative Synthesis Example 2 (Synthesis of Novolak-Type Phenol Resin (A-10) Having Acetal Group-Based Protecting Groups) A gel-like resin (A-10) was obtained by synthesis in the same manner as in Synthesis Example 1, except that phenol was used instead of m-cresol. Resin (A-10) was insoluble in the solvent and could not be evaluated.

[0097] Comparative Synthesis Example 3 (Synthesis of Novolak-Type Phenol Resin (A-11) Having Acetal Group-Based Protecting Groups) A suspension resin (A-11) was obtained by synthesis in the same manner as in Synthesis Example 1, except that m-cresol was replaced with 2,5-xylenol. Resin (A-11) had poor solvent solubility and could not be evaluated.

[0098] Comparative Synthesis Example 4 (Synthesis of Novolak-Type Phenol Resin (A-12) Having Acetal Group-Based Protecting Groups) Except for using catechol instead of m-cresol, 55 g of a novolak phenolic resin powder (A-12) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolak phenolic resin (A-12) was 9,690.

[0099] Comparative Synthesis Example 5 (Synthesis of Novolac Phenolic Resin (A-13)) Except for using 30 g (0.90 mol) of paraformaldehyde instead of 40 g (0.30 mol) of paraaldehyde, 53 g of a novolak phenolic resin powder (A-13) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolak phenolic resin (A-13) was 4,730.

[0100] Comparative Synthesis Example 6 (Synthesis of Novolac Phenolic Resin (A-14)) Except for using 52.3 g (0.90 mol) of propionaldehyde instead of 40 g (0.3 mol) of paraldehyde, 55 g of a novolac phenolic resin powder (A-14) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolac phenolic resin (A-14) was 960.

[0101] Comparative Synthesis Example 7 (Synthesis of Novolak-Type Phenol Resin (A-15) Having Acetal Group-Based Protecting Groups) Except for using paraldehyde instead of salicylaldehyde, 54 g of a novolak phenolic resin powder (A-15) having an acetal group-based protecting group was obtained in the same manner as in Synthesis Example 1. The Mw of the novolak phenolic resin (A-15) was 2,210.

[0102] [Positive-type photosensitive resin composition] Example 1 1.98 g of the novolac phenolic resin (A-1) powder obtained in Synthesis Example 1, 0.02 g of a photoacid generator (manufactured by San-Apro Co., Ltd.: CPI-110TF), and 8 g of propylene glycol monomethyl ether (PGME) were dissolved, and the solution was microfiltered through a 0.1 μm PTFE disk filter to obtain a positive photosensitive resin composition.

[0103] Examples 2 to 8, Comparative Examples 1 to 5 Positive photosensitive resin compositions were prepared in the same manner as in Example 1, except that the novolac phenolic resins shown in Tables 1 and 2 were used as component (A).

[0104] [evaluation] The i-line transmittance of the positive-type photosensitive resin compositions prepared in Examples and Comparative Examples was evaluated. Resist films were prepared using the positive-type photosensitive resin compositions, and the alkali solubility, development contrast, and heat resistance of the resist films were evaluated. Furthermore, the storage stability of the positive-type photosensitive resin compositions was evaluated.

[0105] (1)I-ray transparency The positive-type photosensitive resin composition was diluted with propylene glycol monomethyl ether (PGME) to a solids content of 1% (parts by mass). The transmittance of the resulting 1% diluted positive-type photosensitive resin composition at i-line wavelength (365 nm) was evaluated using a UV-vis absorption spectrophotometer (Shimadzu Corporation: SolidSpec-3700 DUV). The evaluation criteria were as follows: ○: Transmittance (%) is 40% or more ×: Transmittance (%) is less than 40% The evaluation results are shown in Tables 1 and 2. The values ​​in parentheses in Tables 1 and 2 are transmittance values.

[0106] (2) Alkaline developability The positive photosensitive resin composition was applied to a 5-inch silicon wafer to a thickness of approximately 1 μm using a spin coater and dried on a hot plate at 110°C for 60 seconds to obtain a resist film. The resist film was then exposed to 200 mJ / cm using a UV exposure device (UVE-1001SD, manufactured by Minaga Electric Mfg. Co., Ltd.). 2 After exposure, the wafer was subjected to post-exposure baking (PEB) for 90 seconds on a hot plate at 130°C. The resulting wafer with the resist film was immersed in a developer (2.38% aqueous tetramethylammonium hydroxide solution) for 60 seconds and then dried on a hot plate at 110°C for 60 seconds. The resist film thickness was measured before and after immersion in the developer, and the difference was divided by 60 to obtain the alkali solubility ADR1 (Å / s). The evaluation criteria are as follows: ◎: ADR1 is 1000 or more 〇: ADR1 is 500 or more and less than 1000 ×: ADR1 is less than 500 The evaluation results are shown in Tables 1 and 2. The values ​​in brackets in Tables 1 and 2 are the values ​​for ADR1.

[0107] (3) Development contrast In the above (2), the value measured in the same manner without exposing the resist film was taken as ADR2 (Å / s), and the value of ADR1 / ADR2 was taken as the development contrast. The evaluation criteria were as follows: ○: Development contrast is 50 or more ×: Development contrast is less than 50 The evaluation results are shown in Tables 1 and 2. The values ​​in brackets in Tables 1 and 2 are the ADR1 / ADR2 values.

[0108] (4) Storage stability The storage stability was evaluated by the rate of change in ADR2 (2) above. In a positive-type photosensitive resin composition with poor storage stability, the elimination of the protecting group proceeds, resulting in a rapid ADR2. Specifically, the positive-type photosensitive resin composition was stored at room temperature for one month, and the storage stability was evaluated from the ADR2 before and after storage using the following formula. ADR2 change rate = (ADR2 after storage / ADR2 before storage) x 100 The evaluation criteria are as follows: 〇: ADR2 change rate is less than 150% ×: ADR2 change rate is 150% or more The evaluation results are shown in Tables 1 and 2. The values ​​in brackets in Tables 1 and 2 are the ADR2 change rates.

[0109] (5) Heat resistance The positive photosensitive resin composition was applied to a 5-inch diameter silicon wafer using a spin coater and then dried at 110°C for 60 seconds to obtain a 1 μm-thick thin film. This thin film was scraped off and the glass transition temperature (hereinafter abbreviated as "Tg") was measured. Tg was measured using a differential scanning calorimeter (TA Instruments Corporation: Differential Scanning Calorimeter (DSC) Q100) in a nitrogen atmosphere at a temperature range of -100 to 200°C and a heating rate of 10°C / min. The evaluation criteria are as follows: ◎: Tg is 140℃ or higher ○: Tg is 130℃ or higher and less than 140℃ ×: Tg is less than 130°C The evaluation results are shown in Tables 1 and 2. The values ​​in brackets in Tables 1 and 2 are Tg values.

[0110] [Table 1]

[0111] [Table 2]

[0112] In Tables 1 and 2, "Cr" means cresol, "SA" means salicylaldehyde, "BA" means benzaldehyde, "AA" means acetaldehyde, "HA" means formaldehyde, "PA" means propionaldehyde, and "CC" means catechol. In addition, in Tables 1 and 2, "PVE" means propyl vinyl ether, and "CyHDMDVE" means cyclohexanedimethanol divinyl ether.

[0113] For example, the "m-Cr / AA / SA" ratio of "1 / 0.59 / 0.4" in Example 1 means that the novolak phenolic resin, which is component (A) in Example 1, is composed of units derived from m-cresol, units derived from acetaldehyde, and units derived from salicylaldehyde, with a molar ratio of m-cresol:units derived from acetaldehyde:units derived from salicylaldehyde of 1:0.59:0.4.

[0114] The results in Tables 1 and 2 show that the positive photosensitive resin composition of the present invention has excellent i-line transparency and storage stability, and that the resist film using the positive photosensitive resin composition of the present invention has excellent alkali solubility, development contrast, and heat resistance.

Claims

1. A positive photosensitive resin composition comprising the following components (A) to (C): (A) A novolak-type phenolic resin containing a phenol structural unit (a1) derived from m-cresol and / or o-cresol, an aldehyde structural unit (a2) derived from acetaldehyde, and an aldehyde structural unit (a3) ​​derived from salicylaldehyde, and having an acetal group-based protecting group. (B) Photoacid generator (C) Solvent

2. 2. The positive photosensitive resin composition according to claim 1, wherein the content of the aldehyde structural unit (a4) derived from formaldehyde in the component (A) is 10% by mass or less.

3. 3. The positive photosensitive resin composition according to claim 1, wherein the molar ratio [(a1):(a2):(a3)] of the phenol structural unit (a1) derived from m-cresol, the aldehyde structural unit (a2) derived from acetaldehyde, and the aldehyde structural unit (a3) ​​derived from salicylaldehyde in the component (A) satisfies 1.0:0.3-0.99:0.01-0.

7.

4. 3. The positive photosensitive resin composition according to claim 1, wherein the component (A) further comprises an aldehyde structural unit (a5) derived from benzaldehyde.

5. 3. The positive photosensitive resin composition according to claim 1, wherein the acetal group-based protecting group is a group represented by the following formula (1): 【Chemistry 3】 (In the formula, R １ and R ２ are each independently a hydrogen atom, a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R ３ is a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. ３ is R １ or R ２ may be bonded to form a ring. * is bonded to the benzene ring that constitutes the main chain of the novolac phenolic resin.)

6. 3. The positive photosensitive resin composition according to claim 1, wherein component (A) is obtained by reacting a novolak phenolic resin obtained by polycondensing m-cresol, acetaldehyde, and salicylaldehyde in an organic solvent in a molar ratio of m-cresol:acetaldehyde:salicylaldehyde = 1.0:0.3 to 0.99:0.01 to 0.7 using an acid catalyst, with a compound that forms an acetal group-based protecting group.

7. 7. The positive photosensitive resin composition according to claim 6, wherein the compound forming the acetal group-based protecting group is a compound represented by the following formula (2): 【Chemistry 4】 (In the formula, R ３ is a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. R ４ ~R ６ are each independently a hydrogen atom, a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 3 to 20 carbon atoms, a cyclic alkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

8. 7. The positive photosensitive resin composition according to claim 6, wherein the compound forming the acetal group-based protecting group is propyl vinyl ether.

9. 5. The positive photosensitive resin composition according to claim 1, wherein the total content of the phenol structural unit (a1) derived from m-cresol, the aldehyde structural unit (a2) derived from acetaldehyde, the aldehyde structural unit (a3) ​​derived from salicylaldehyde, and the aldehyde structural unit (a5) derived from benzaldehyde in the component (A) is 50% by mass or more.

10. A photosensitive film obtained by drying the positive photosensitive resin composition according to claim 1 or 2.

11. A resist film obtained from the positive photosensitive resin composition according to claim 1 or 2.

12. A resist underlayer film obtained from the positive photosensitive resin composition according to claim 1 or 2.

13. A permanent resist film obtained from the positive photosensitive resin composition according to claim 1 or 2.

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