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

Abstract

The invention provides a positive photosensitive resin composition, a resist film, a resist underlayer film, and a resist permanent film. The invention provides a positive photosensitive resin composition which is capable of obtaining a resist film with excellent developability and heat resistance and has good storage stability and thick film forming property. A positive photosensitive resin composition containing the following components (A) to (C), (A) A novolac phenolic resin having an acetal group protecting group / (B) a photoacid generator / (C) a solvent, wherein the molar ratio of a structural unit (a1) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, a structural unit (a3) derived from salicylaldehyde, and a structural unit (a4) derived from formaldehyde [(a1): (a2): (a3): (a4)] is 1.0: 0.3-0.8: 0.3-0.8: 0.01-0.2.

Description

TECHNICAL FIELD

[0001] The present application relates to a positive photosensitive resin composition, a resist film, a resist underlayer film, and a resist permanent film. BACKGROUND

[0002] In recent years, with the miniaturization of electronic devices, the high density of semiconductor packages is continuously developed. In the past, in the manufacture of semiconductor packages of IC, LSI, an i-line positive photoresist using an alkali-soluble resin (for example, a novolak type phenol formaldehyde (phenol novolak) resin) and a naphthoquinone diazide compound-based photosensitizer has been generally widely used. However, the miniaturization using i-line is approaching the limit. In particular, in plating resists and the like for forming a rewiring layer used in front-end semiconductor packages, it is required to form fine wiring with a thick film of several μm or more. In such a thick film of several μm, the conventional naphthoquinone type cannot cause a sufficient amount of light to reach the bottom of the film, and thus there is a problem that the resist layer at the bottom of the pattern does not undergo alkali dissolution, and it is difficult to form a high aspect ratio pattern.

[0003] In order to solve the above problem, instead of using a naphthoquinone diazide compound-based photosensitizer, a chemical amplification positive photoresist used in photolithography using a KrF, ArF, EUV, or the like is studied for photolithography using i-line (for example, Patent Document 1).

[0004] If a photosensitive resin film using a chemical amplification positive photoresist is irradiated with light, acid is generated from a photoacid generator, and the generated acid (proton) acts as an acid catalyst to cause a protective group of an acid-decomposable resin to be detached to expose an alkali-dissolvable group. In the chemical amplification positive photoresist, after the protective group is detached, the acid is catalytically regenerated to cause other protective groups to be detached, and thus a positive pattern having high alkali solubility can be produced even with a small amount of light. Therefore, alkali dissolution at the bottom of the film, which is a problem in thick film production, becomes possible.

[0005] However, in the positive photosensitive resin composition using the m-cresol-based phenol novolak resin described in Patent Document 1, the sensitivity is still insufficient, and the generation of residual film at the bottom of the pattern after development is not solved.

[0006] Therefore, a chemical amplification positive photosensitive resin composition composed of o-cresol and p-cresol in addition to m-cresol has been studied (for example, Patent Document 2). However, in the photosensitive resin composition described in Patent Document 2, the alkali solubility is still insufficient, and the generation of residual film at the bottom of the pattern after development still remains, and in addition, there is a problem that the storage stability and heat resistance are also low.

[0007] To improve the storage stability and heat resistance, an i-line corresponding type chemically amplified positive type resin composition using a highly aromatic phenol novolak resin has been proposed (for example, Patent Document 3). However, the positive photosensitive resin composition described in Patent Document 3, while having excellent storage stability and heat resistance, has a problem in that it is difficult to produce a thick film.

[0008] As described above, with the high densification of semiconductor packages, there is a demand for development of a photosensitive resin composition for a chemically amplified positive type photoresist that can develop a thick film pattern having a high aspect ratio without residue generation, and that has good storage stability, and high heat resistance of the obtained resist film.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2003-149816

[0012] Patent Document 2: Japanese Patent Application Publication No. 2019-203097

[0013] Patent Document 3: Japanese Patent Application Publication No. 2024-69146 SUMMARY

[0014] Problems to be Solved by the Invention

[0015] An object of the present application is to provide a positive photosensitive resin composition that can obtain a resist film having excellent developability and heat resistance, and that has good storage stability and thick film production properties.

[0016] Method for Solving the Problem

[0017] The present inventors and others conducted intensive studies in order to solve the above problem, and as a result, found that a positive photosensitive resin composition containing a novolak type phenolic resin having a specific structural unit and in which at least a portion of the phenolic hydroxyl groups is substituted with an acetal-based protecting group, a photoacid generator, and a solvent has high i-line transmittance, thereby completing the present application.

[0018] That is, the present application relates to a positive photosensitive resin composition containing the following components (A) to (C).

[0019] (A) a novolak type phenolic resin having a molar ratio [(a1):(a2):(a3):(a4)] of 1.0:0.3 to 0.8:0.3 to 0.8:0.01 to 0.2 of a structural unit (a1) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, a structural unit (a3) derived from salicylaldehyde, and a structural unit (a4) derived from formaldehyde, and having an acetal-based protecting group,

[0020] (B) a photoacid generator,

[0021] (C) a solvent.

[0022] The present application also relates to a photosensitive film obtained by drying the positive photosensitive resin composition.

[0023] The present application also relates to a resist film obtained from the positive photosensitive resin composition.

[0024] The present application also relates to a resist underlayer film obtained from the positive photosensitive resin composition.

[0025] The present application also relates to a resist permanent film obtained from the positive photosensitive resin composition.

[0026] Effects of the Invention

[0027] According to the present application, it is possible to provide a positive photosensitive resin composition which can obtain a resist film excellent in developability and heat resistance, and which is good in storage stability and thick film formability. DETAILED DESCRIPTION

[0028] Hereinafter, a mode for carrying out the present application will be described.

[0029] Note that, in the present specification, "x to y" indicates a numerical range of "x or more and y or less". The upper limit value and the lower limit value described with respect to the numerical range can be combined arbitrarily.

[0030] In addition, a mode obtained by combining two or more of the respective modes of the present application described below is also a mode of the present application.

[0031] [Positive Photosensitive Resin Composition]

[0032] The positive photosensitive resin composition of one embodiment of the present application contains the following components (A) to (C).

[0033] (A) a phenol novolak type phenol resin having a molar ratio [(al):(a2):(a3):(a4)] of 1.0:0.3 to 0.8:0.3 to 0.8:0.01 to 0.2 of a structural unit (al) derived from m-cresol, a structural unit (a2) derived from benzaldehyde, a structural unit (a3) derived from salicylaldehyde, and a structural unit (a4) derived from formaldehyde, and having a protective group of an acetal group type,

[0034] (B) a photoacid generator,

[0035] (C) a solvent.

[0036] In the present embodiment, the novolak-type phenolic resin has an acetal group-based protecting group, thereby producing a synergistic effect with a photoacid generator when the positive photosensitive resin composition is made into a resist film or the like. Specifically, in the exposed portion, the acetal group-based protecting group is detached from component (A) by the acid generated from the photoacid generator, but on the other hand, the acetal group-based protecting group is not detached from component (A) in the unexposed portion. Thus, a positive photosensitive resin composition which is excellent in i-line transmittance, and which is excellent in developability, development contrast, and heat resistance when made into a resist film or the like can be obtained. In addition, in the present embodiment, the novolak-type phenolic resin has a small amount of a structural unit (a4) derived from formaldehyde in addition to the structural unit (al) derived from m-cresol, the structural unit (a2) derived from benzaldehyde, and the structural unit (a3) derived from salicylaldehyde. Thus, it is possible to impart moderate flexibility to the novolak-type phenolic resin which is high in rigidity, and as a result, the thick film formability is improved.

[0037] • Component (A)

[0038] In the novolak-type phenolic resin of component (A), the molar ratio [(al):(a2):(a3):(a4)] of the structural unit (al) derived from m-cresol, the structural unit (a2) derived from benzaldehyde, the structural unit (a3) derived from salicylaldehyde, and the structural unit (a4) derived from formaldehyde is 1.0:0.3-0.8:0.3-0.8:0.01-0.2, and the novolak-type phenolic resin has an acetal group-based protecting group.

[0039] From the viewpoint of obtaining a resist film or the like which is higher in developability and higher in heat resistance, and from the viewpoint of obtaining a composition which has thick film formability, the molar ratio [(al):(a2):(a3):(a4)] is preferably 1.0:0.35-0.75:0.35-0.75:0.05-0.2, more preferably 1.0:0.4-0.65:0.4-0.65:0.05-0.1.

[0040] Component (A) can include a structural unit other than the structural unit (al) derived from m-cresol, the structural unit (a2) derived from benzaldehyde, the structural unit (a3) derived from salicylaldehyde, and the structural unit (a4) derived from formaldehyde. As the structural unit other than (al) to (a4), a structural unit derived from a phenol other than m-cresol, benzaldehyde, salicylaldehyde, and formaldehyde can be mentioned.

[0041] As the above phenol, phenol, o-cresol, p-cresol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, and the like can be mentioned.

[0042] As the above-mentioned aldehyde, acetaldehyde, chloroacetaldehyde, 4-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, and the like can be given.

[0043] The total content of the above-mentioned structural units (al), (a2), (a3), and (a4) in the component (A) is preferably 30% by mass or more, more preferably 50% by mass or more, and further preferably 90% by mass or more.

[0044] The total content of the above-mentioned structural units (al), (a2), (a3), and (a4) can be substantially 100% by mass. Note that substantially 100% by mass means a case where a structural unit other than the above-mentioned structural units (al), (a2), (a3), and (a4) is inevitably contained.

[0045] The acetal-based protecting group possessed by the component (A) is preferably a group represented by the following formula (1).

[0046]

[0047] (In the formula, R1and R2are each independently a hydrogen atom, a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, or an aryl group having a carbon number of 6 to 20.

[0048] R3is a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 20, or an aralkyl group having a carbon number of 7 to 20. R3may combine with R1or R2to form a ring.

[0049] *binds to a benzene ring constituting a main chain of the novolak-type phenol-aldehyde resin.

[0050] In the component (A), at least a part of the phenolic hydroxyl groups of the novolak-type phenol-aldehyde resin is protected by the acetal-based protecting group represented by the above-mentioned formula (1). The acetal-based protecting group can be detached by an acid generated from a photo-acid generator.

[0051] The fact that the component (A) has the acetal-based protecting group can be confirmed by C 13 -NMR.

[0052] In the formula (1), as the linear alkyl group having a carbon number of 1 to 20, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and the like can be given.

[0053] As the branched alkyl group having a carbon number of 3 to 20, an isopropyl group, a sec-butyl group, a tert-butyl group, a neopentyl group, an isoamyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,3-dimethylbutyl group, and the like can be given.

[0054] Examples of cyclic alkyl groups having 3 to 20 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and adamantyl. Cyclic alkyl groups may have substituents such as the aforementioned straight-chain alkyl groups.

[0055] Examples of aryl groups with 6 to 20 carbon atoms include phenyl, naphthyl, and anthracene. Aryl groups may have substituents such as alkyl groups.

[0056] Arane refers to alkyl (C n H 2n+1 An alkyl group in which one or more hydrogen atoms are replaced by an aryl group. The aryl group may have the aforementioned alkyl or other substituents. Specifically, examples include phenylmethyl, tolylmethyl, xylmethyl, naphthylmethyl, hydroxynaphthylmethyl, dihydroxynaphthylmethyl, phenylethyl, hydroxyphenylethyl, dihydroxyphenylethyl, tolylethyl, xylethyl, naphthylethyl, hydroxynaphthylethyl, and dihydroxynaphthylethyl. The number of carbon atoms is preferably, for example, 7 to 15.

[0057] R3 can combine with R1 or R2 to form a ring. Examples of rings include oxygen-containing heterocycles such as furan rings and pyran rings.

[0058] Examples of acetal-based protecting groups represented by formula (1) above include, specifically, 1-methoxyethoxy, 1-ethoxyethoxy, 1-propoxyethoxy, 1-butoxyethoxy, 2-methoxypropoxy, 2-ethoxypropoxy, 1-(2-methylpropoxy)ethoxy, 1-(1-propoxy)propoxy, 1-ethoxybutoxy, 1-(2-methoxyethoxy)ethoxy, 1-(2-acetoxyethoxy)ethoxy, tetrahydrofuran-2-yl, 1-[(1-adamantoxy)ethoxy]ethyl, 1-[2-(1-adamantoxycarbonyloxy)ethoxy]ethyl, tetrahydro-2-pyranyl, tetrahydro-2-furanyl, 1-(cyclohexyloxy) 1-(2-cyclohexyl)ethoxy, 1-phenoxyethoxy, 1-(2-cyclohexyl)ethoxyethoxy, (1-adamantoxy)ethoxy, (2-adamantoxy)ethoxy, (1-adamantylmethoxy)ethoxy, (2-adamantylethoxy)ethoxy, 1-(1-bicyclo[2.2.1]heptoxy)ethoxy, 1-(2-bicyclo[2.2.1]heptoxy)ethoxy, 1-(1-bicyclo[2.2.1]heptoxy)ethoxy, 1-(2-bicyclo[2.2.1]heptoxymethoxy)ethoxy, 2-(1,7,7-trimethylbicyclo[2.2.1]heptoxy)ethoxy, 2-(1-isopropyl-4-methylcyclohexyl)ethoxy, etc.

[0059] The preferred protecting group, as represented by the above formula (1), is 1-propoxyethoxy.

[0060] The protection ratio of the phenolic hydroxyl group in the novolak-type phenol resin in component (A) (the proportion of the bond of the acetal-based protecting group with respect to the total amount of the phenolic hydroxyl group in the novolak-type phenol resin) is preferably 1 to 50 mol%, more preferably 2 to 40 mol%, even more preferably 5 to 25 mol%, and further preferably 7.5 to 15 mol% from the viewpoint of making the dissolution rate with respect to an alkali developer appropriate or the like.

[0061] The weight average molecular weight of the novolak-type phenol resin as component (A) is preferably 1,000 or more, and more preferably 1,500 or more. In addition, it is preferably 30,000 or less, and more preferably 20,000 or less, and even more preferably 15,000 or less. If the weight average molecular weight is 1,000 or more, it is high in heat resistance, and thus is preferred. On the other hand, if the weight average molecular weight is 30,000 or less, it is high in sensitivity, and thus is preferred. Note that in the present specification, the weight average molecular weight is measured under the conditions described in the Examples.

[0062] Component (A) is obtained by subjecting m-cresol, benzaldehyde, salicylaldehyde, and formaldehyde to condensation polymerization in an organic solvent at a molar ratio (m-cresol:benzaldehyde:salicylaldehyde:formaldehyde) of 1.0:0.3 to 0.8:0.3 to 0.8:0.01 to 0.2 using an acid catalyst to obtain a novolak-type phenol resin (a), and further reacting with a compound that forms an acetal-based protecting group. Note that, for example, a compound such as paraformaldehyde, which becomes formaldehyde by heating, can be used as a starting material.

[0063] Next, the synthesis of the novolak-type phenol resin (a) and the introduction of the acetal-based protecting group will be described.

[0064] (Synthesis of the novolak-type phenol resin (a))

[0065] The novolak-type phenol resin (a) can be obtained, for example, by dissolving the raw material compounds in a reaction solvent and performing a synthesis reaction using an acid catalyst according to a conventional method.

[0066] As the reaction solvent used in the production of the novolak-type phenol resin (a), for example, methanol, ethanol, 1-propanol, 2-propanol, butanol, hexanol, ethylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, methyl ethyl ketone, methyl isobutyl ketone, toluene, or the like can be given, of which one or more selected from the group consisting of ethanol, 1-propanol, and 2-propanol is preferred, and ethanol or methyl isobutyl ketone is more preferred.

[0067] The molar ratio of m-cresol, benzaldehyde, salicylaldehyde and formaldehyde in the reaction solvent (m-cresol: benzaldehyde: salicylaldehyde: formaldehyde) is preferably 1.0: 0.35 to 0.75: 0.35 to 0.75: 0.05 to 0.2, more preferably 1.0: 0.4 to 0.65: 0.4 to 0.65: 0.05 to 0.1, from the viewpoint of obtaining a resist film having higher developability and higher heat resistance, and from the viewpoint of obtaining a composition having thick film film-forming properties.

[0068] In the condensation of m-cresol, benzaldehyde, salicylaldehyde and formaldehyde in an organic solvent to obtain the novolak type phenolic resin (a), as described above, a phenol and an aldehyde other than m-cresol, benzaldehyde, salicylaldehyde and formaldehyde can be contained in the organic solvent.

[0069] The proportion of the total mass of m-cresol, benzaldehyde, salicylaldehyde and formaldehyde in the reaction solvent, relative to the total mass of the starting materials that can become the constituent structural units of component (A), is preferably 30 mass% or more, more preferably 50 mass% or more, and further preferably substantially 100 mass%, from the viewpoint of obtaining a resist film having heat resistance even at low temperature curing in addition to high sensitivity.

[0070] The amount of use of the above reaction solvent is preferably 20 parts by mass or more, more preferably 50 parts by mass or more, relative to 100 parts by mass of the starting material for the derivation of the constituent structural units of component (A), from the viewpoint of reaction uniformity. In addition, it is preferably 500 parts by mass or less, more preferably 300 parts by mass or less.

[0071] As the acid catalyst used in the production of the novolak type phenolic resin (a), inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid; organic acids such as oxalic acid, acetic acid, p-toluenesulfonic acid, and the like can be exemplified. Among these, in order to further promote the reaction, inorganic acids, p-toluenesulfonic acid are preferred, and p-toluenesulfonic acid is more preferred.

[0072] The amount of addition of the acid catalyst is not particularly limited, and is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, relative to 100 parts by mass of the starting material for the derivation of the constituent structural units of component (A). In addition, it is preferably 150 parts by mass or less, more preferably 100 parts by mass or less.

[0073] The reaction temperature at the time of condensation of the starting materials of the novolak type phenolic resin (a) is preferably 30°C or more, more preferably 40°C or more, from the aspect of promoting the reaction and efficiently increasing the molecular weight. In addition, it is preferably 100°C or less, more preferably 80°C or less.

[0074] The reaction time is preferably 4 hours or more, more preferably 12 hours or more. In addition, it is preferably 32 hours or less, more preferably 24 hours or less.

[0075] (Introduction of acetal-based protecting group)

[0076] The method of introducing the acetal-based protecting group is not particularly limited. For example, a method can be cited in which the novolak-type phenolic resin (a) and a compound forming an acetal-based protecting group are put into a reaction solvent, and a reaction is performed using an acid catalyst.

[0077] The acetal-based protecting group is generated by reacting the phenolic hydroxyl group in the novolak-type phenolic resin (a) with a compound forming an acetal-based protecting group in an acid catalyst, and it protects the phenolic hydroxyl group in the novolak-type phenolic resin (a).

[0078] As the reaction solvent used when the acetal-based protecting group is introduced, the reaction solvent used in the synthesis of the above-described novolak-type phenolic resin (a) can be appropriately used. As the reaction solvent used when the acetal-based protecting group is introduced, methyl isobutyl ketone is preferable.

[0079] The acid catalyst used when the acetal-based protecting group is introduced can be appropriately used from among the acid catalysts used in the synthesis of the above-described novolak-type phenolic resin (a). Among them, in order to further promote the reaction, an inorganic acid, p-toluenesulfonic acid is preferable, and p-toluenesulfonic acid is more preferable.

[0080] When the acetal-based protecting group is introduced, the reaction time is preferably 1 hour or more, and more preferably 2 hours or more. In addition, it is preferably 10 hours or less, and more preferably 6 hours or less.

[0081] When the acetal-based protecting group is introduced, the reaction temperature can be set to the same reaction temperature as in the synthesis of the above-described novolak-type phenolic resin (a).

[0082] In the present embodiment, the compound forming an acetal-based protecting group is preferably a compound represented by the following formula (2).

[0083]

[0084] (In the formula, R3is a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 20, or an aralkyl group having a carbon number of 7 to 20.

[0085] R4to R6are each independently a hydrogen atom, a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, or an aryl group having a carbon number of 6 to 20.)

[0086] In formula (2), specific examples of the linear alkyl group having a carbon number of 1 to 20, the branched alkyl group having a carbon number of 3 to 20, the cyclic alkyl group having a carbon number of 3 to 20, the aryl group having a carbon number of 6 to 20, and the aralkyl group having a carbon number of 7 to 20 are the same as in the above-described formula (1).

[0087] Any two of R3, R4, R5, and R6may combine to form a ring, for example, R3and R6may combine to form a cyclic ether.

[0088] As the compound forming the acetal group-based protecting group represented by the above formula (2), there can be mentioned 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, [(adamantane-1-yl)methyl] vinyl ether, [(adamantane-2-yl)methyl] vinyl ether, 1-methoxypropene, 2-methoxy-2-butene, 2-methoxy-3-methyl-2-butene, 2-(vinyloxy)bicyclo[2.2.1]heptane, 2-(vinyloxy)-1,7,7-trimethylbicyclo[2.2.1]heptane, 2-[(vinyloxy)methyl]bicyclo[2.2.1]heptane, 2-[(vinyloxy)ethyl]bicyclo[2.2.1]heptane, 3-(vinyloxy)-1,1-bicyclohexane, 3,4-dihydropyran, and the like. Of these, propyl vinyl ether is preferred.

[0089] In the present embodiment, from the viewpoint of obtaining good developability (sensitivity) and development contrast, the blending amount of the compound represented by the above formula (2) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, relative to 100 parts by mass of the novolak-type phenol resin (a). In addition, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less.

[0090] • Component (B)

[0091] The photoacid generator as the component (B) refers to a compound that generates an acid by bond cleavage due to exposure. By containing a photoacid generator, in the exposed portion, the acetal group-based protecting group is detached from the component (A) using the acid generated from the photoacid generator. By this reaction, the phenolic hydroxyl group of the novolak-type phenol resin is exposed, and thus it is possible to produce a difference in alkali solubility between the unexposed portion and the exposed portion, and to improve developability (sensitivity) and development contrast when the positive-working photosensitive resin composition is made into a resist film.

[0092] The photoacid generator is not particularly limited, and a publicly known photoacid generator can be used. For example, there can be mentioned organic halogen compounds, sulfonic acid esters, onium salts (sulfonium salts, phosphonium salts, iodonium salts, and the like), diazonium salts, diazomethane compounds, nitrobenzyl compounds, disulfone compounds, triazine-based photoacid generators, and the like.

[0093] In one embodiment, the photoacid generator is not a naphthoquinone diazide compound.

[0094] As specific examples of the photoacid generator, the following can be given.

[0095] halogen-substituted paraffin hydrocarbon compounds such as 1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon tetrabromide, iodoform, and the like;

[0096] halogen-substituted paraffin hydrocarbon compounds such as 1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon tetrabromide, iodoform, and the like;

[0097] halogen-substituted paraffin hydrocarbon compounds such as 1,2,3,4-tetrabromobutane, 1,1,2,2-tetrabromoethane, carbon tetrabromide, iodoform, and the like;

[0098] sulfone compounds such as diphenyl disulfone, and the like;

[0099] sulfone compounds such as diphenyl disulfone, and the like;

[0100] sulfone compounds such as diphenyl disulfone, and the like;

[0101] 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)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, 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-trifluoromethoxyphenylsulfonyl)diazomethane, 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) 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, 2,4-dimethylphenylsulfonyl-(2,3,4-trimethylphenylsulfonyl) diazomethane, phenylsulfonyl-(2-fluorophenylsulfonyl) diazomethane, phenylsulfonyl-(3-fluorophenylsulfonyl) diazomethane, phenylsulfonyl-(4-fluorophenylsulfonyl) diazomethane, and the like sulfonyl diazomethane compounds;

[0102] o-nitrobenzyl-p-toluenesulfonate and the like o-nitrobenzyl ester compounds;

[0103] N,N'-di(phenylsulfonyl)hydrazide and the like sulfonyl hydrazide compounds;

[0104] sulfonium cations such as triarylsulfonium, triarylamylsulfonium and the like and sulfonic acid salts such as fluoroalkanesulfonate, arenesulfonate, alkanesulfonate and the like, namely sulfonium salts;

[0105] iodonium cations such as diaryliodonium and the like and sulfonic acid salts such as fluoroalkanesulfonate, arenesulfonate, alkanesulfonate and the like, namely iodonium salts;

[0106] bis(alkylsulfonyl) diazomethane, bis(cycloalkylsulfonyl) diazomethane, bis(perfluoroalkylsulfonyl) diazomethane, bis(arylsulfonyl) diazomethane, bis(aralkylsulfonyl) diazomethane and the like bis-sulfonyl diazomethane compounds;

[0107] N-sulfonyloxy imide compounds composed of combinations of dicarboxylic acid imide compounds and sulfonic acid salts such as fluoroalkanesulfonate, arenesulfonate, alkanesulfonate and the like;

[0108] benzoin tosylate, benzoin mesylate, benzoin butane sulfonate and the like benzoin sulfonic acid salt compounds;

[0109] polyhydroxy arene sulfonic acid salt compounds obtained by substituting all of the hydroxyl groups of polyhydroxy arene compounds with sulfonic acid salts such as fluoroalkanesulfonate, arenesulfonate, alkanesulfonate and the like;

[0110] a fluorinated alkane sulfonic acid (poly)nitrobenzyl ester, an aromatic sulfonic acid (poly)nitrobenzyl ester, an alkane sulfonic acid (poly)nitrobenzyl ester, and the like;

[0111] a fluorinated alkane sulfonic acid (poly)fluoroalkyl benzyl ester, an aromatic sulfonic acid (poly)fluoroalkyl benzyl ester, an alkane sulfonic acid (poly)fluoroalkyl benzyl ester, and the like;

[0112] a bis(aryl sulfonyl) alkane compound;

[0113] a bis-O-(aryl sulfonyl)-α-dialkyl glyoxime, a bis-O-(aryl sulfonyl)-α-dicycloalkyl glyoxime, a bis-O-(aryl sulfonyl)-α-diaryl glyoxime, a bis-O-(alkyl sulfonyl)-α-dialkyl glyoxime, a bis-O-(alkyl sulfonyl)-α-dicycloalkyl glyoxime, a bis-O-(alkyl sulfonyl)-α-diaryl glyoxime, a bis-O-(fluoroalkyl sulfonyl)-α-dialkyl glyoxime, a bis-O-(fluoroalkyl sulfonyl)-α-dicycloalkyl glyoxime, a bis-O-(fluoroalkyl sulfonyl)-α-diaryl glyoxime, a bis-O-(aryl sulfonyl)-α-dialkyl 1,2-cyclohexanedionenioxime, a bis-O-(aryl sulfonyl)-α-dicycloalkyl 1,2-cyclohexanedionenioxime, a bis-O-(aryl sulfonyl)-α-diaryl 1,2-cyclohexanedionenioxime, a bis-O-(alkyl sulfonyl)-α-dialkyl 1,2-cyclohexanedionenioxime, a bis-O-(alkyl sulfonyl)-α-dicycloalkyl 1,2-cyclohexanedionenioxime, a bis-O-(alkyl sulfonyl)-α-diaryl 1,2-cyclohexanedionenioxime, a bis-O-(fluoroalkyl sulfonyl)-α-dialkyl 1,2-cyclohexanedionenioxime, a bis-O-(fluoroalkyl sulfonyl)-α-dicycloalkyl 1,2-cyclohexanedionenioxime, a bis-O-(fluoroalkyl sulfonyl)-α-diaryl 1,2-cyclohexanedionenioxime, and the like;

[0114] an aryl sulfonyloxy imino aryl acetonitrile, an alkyl sulfonyloxy imino aryl acetonitrile, a fluoroalkyl sulfonyloxy imino aryl acetonitrile, a ((aryl sulfonyl)oxy imino-thiophene-ylidene) aryl acetonitrile, a ((alkyl sulfonyl)oxy imino-thiophene-ylidene) aryl acetonitrile, a ((fluoroalkyl sulfonyl)oxy imino-thiophene-ylidene) aryl acetonitrile, a bis(aryl sulfonyloxy imino) arylene diacetonitrile, a bis(alkyl sulfonyloxy imino) arylene diacetonitrile, a bis(fluoroalkyl sulfonyloxy imino) arylene diacetonitrile, an aryl fluoroalkanone-O-(alkyl sulfonyl) oxime, an aryl fluoroalkanone-O-(aryl sulfonyl) oxime, an aryl fluoroalkanone-O-(fluoroalkyl sulfonyl) oxime, and the like modified oxime compound.

[0115] The photoacid generator can be used alone as one kind, or two or more kinds can be used in combination.

[0116] From the viewpoint of obtaining good i-line transmittance, good developability (sensitivity), heat resistance when the positive photosensitive resin composition is made into a resist film or the like, 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 the component (A). In addition, it is preferably 20 parts by mass or less, more preferably 5 parts by mass or less.

[0117] • Component (C)

[0118] As the component (C), i.e., the solvent, polar aprotic solvents such as N-methyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ketones such as acetone, methyl ethyl ketone, diisobutyl ketone, esters such as ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, propylene glycol monomethyl ether acetate, 3-methyl-3-methoxybutyl acetate, alcohols such as ethyl lactate, methyl lactate, diacetone alcohol, 3-methyl-3-methoxybutanol, and aromatic hydrocarbons such as toluene, xylene, and the like can be given. These solvents can be used alone or two or more kinds thereof can be used in combination.

[0119] From the viewpoint of the flowability of the composition and the uniformity of the coating film obtained by a coating method such as spin coating, the amount of the solvent to be added in the positive photosensitive resin composition of the present embodiment is preferably an amount in which the solid content concentration of the composition becomes 5% by mass or more. In addition, it is preferably an amount in which it becomes 65% by mass or less.

[0120] • Other Components

[0121] In one embodiment, in the positive photosensitive resin composition, in addition to the above components (A) to (C), various additives can be added within a range not impairing the effects of the present application. As the additives, fillers, pigments, surfactants such as leveling agents, adhesion improvers, dissolution accelerators, and the like can be given.

[0122] The positive photosensitive resin composition of the present embodiment can be prepared by stirring and mixing the above components (A) to (C) and various additives as needed by a usual method to make a uniform liquid.

[0123] When a solid substance such as a filler or a pigment is added to the composition, it is preferable to use a dispersing device such as a dissolver, a homogenizer, or a three-roll mill to disperse and mix. In addition, in order to remove coarse particles and impurities, the composition can be filtered using a screen filter, a membrane filter, or the like.

[0124] The positive photosensitive resin composition of the present embodiment can be suitably used for applications such as resist films, resist underlayer films, and resist permanent films.

[0125] The positive photosensitive resin composition of the present application can be made into a resist film, a resist underlayer film, and a resist permanent film (hereinafter, sometimes collectively referred to as a resist film or the like) by the same use method as that of a general positive photosensitive resin composition.

[0126] Specifically, by applying the positive photosensitive resin composition of the present application on an object to be subjected to photolithography and performing pre-baking, a film of the photosensitive resin composition from which the solvent has been removed (a photosensitive film) can be obtained.

[0127] As the application method, spin coating, roll coating, flow coating, dip coating, spray coating, doctor blade coating, and the like can be given. The pre-baking can be performed, for example, by heating at a temperature of 60°C or higher and 150°C or lower for a time of 30 seconds or more and 600 seconds or less. In addition, the positive photosensitive resin composition of the present application can be applied to a glass substrate, a silicon substrate, an aluminum substrate, a silicon carbide substrate, a silicon nitride substrate, a gallium nitride substrate, a transparent conductive film, a copper substrate, a copper-plated substrate, and the like as an object to be coated.

[0128] By the catalytic reaction of the acid generated by the exposure of the photosensitive film, the acetal-based protecting group is detached from the component (A), and the solubility of the exposed portion in the alkali developer is greatly increased. As the light source used in the exposure, for example, infrared light, visible light, ultraviolet light, far ultraviolet light, X-rays, and an electron beam can be given. Among these light sources, ultraviolet light is preferred, and the g-line (wavelength: 436 nm) and the i-line (wavelength: 365 nm) of a high-pressure mercury lamp are suitable.

[0129] After the exposure, in order to promote the detachment of the acetal-based protecting group from the component (A), a heating treatment can be performed at around 100°C to 150°C.

[0130] The photosensitive film obtained from the positive photosensitive resin composition of the present application has high alkali solubility in the exposed portion, and the difference in the alkali solubility from the unexposed portion is large, and thus patterning can be performed at high resolution. Therefore, it can be suitably used as a resist film or the like. Note that, in the present application, the resist film or the like also includes any one of the photosensitive film before the exposure and the non-photosensitive film after the exposure.

[0131] As the alkali developer used in the development after the exposure, an aqueous alkali solution of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, and the like; 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 dimethyl ethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; cyclic amines such as pyrrole and piperidine; and the like can be given.

[0132] An alkali developer can also be used by adding, as necessary, an alcohol, a surfactant, or the like. The alkali concentration of the alkali developer is preferably in the range of 2 to 5% by mass, and an aqueous solution of tetramethylammonium hydroxide at 2.38% by mass is generally used.

[0133] In the case where the positive photosensitive resin composition of the present application is used for the application of an underlayer film for a resist (BARC film), the positive photosensitive resin composition of the present application can be directly used as a composition for an underlayer film for a resist, or various additives such as other resin components, surfactants, dyes, fillers, crosslinking agents, and dissolution promoters can be added as necessary.

[0134] As the other resin components, for example, various novolak resins, polyaddition resins of alicyclic diene compounds such as dicyclopentadiene and phenolic compounds, modified novolak resins containing phenolic hydroxyl compounds and alkoxyl aromatic compounds, phenol aralkyl resins (Xylok resins), naphthol aralkyl resins, trimethylolmethane resins, tetraphenol ethane resins, biphenyl-modified phenol resins, biphenyl-modified naphthol resins, aminotriazine-modified phenol resins, and various vinyl polymers can be mentioned.

[0135] In the case where the other resin components are used, the blending ratio of the positive photosensitive resin composition of the present application and the other resin can be arbitrarily set depending on the application. For example, it is preferable that the other resin be in the range of 0.5 to 100 parts by mass relative to 100 parts by mass of the component (A).

[0136] The composition for an underlayer film for a resist can be prepared by mixing the above components by using a blender or the like. In the case where the composition for an underlayer film for a resist contains fillers or pigments, it can be prepared by dispersing or mixing using a dispersing device such as a dissolver, a homogenizer, or a three-roll mill.

[0137] In order to form an underlayer film for a resist from the composition for an underlayer film for a resist, for example, the above composition for an underlayer film for a resist is applied to an object to be subjected to photolithography such as a silicon substrate, and is dried at a temperature in the range of 100 to 200°C, and is further heat-cured at a temperature in the range of 250 to 400°C. Subsequently, a resist pattern is formed by performing a usual photolithography operation on the underlayer film, and dry etching treatment is performed using a halogen plasma gas or the like, whereby a resist pattern based on a multilayer resist method can be formed.

[0138] In the case where the positive photosensitive resin composition of the present application is used for the application of a permanent film for a resist, other resins, surfactants, dyes, fillers, crosslinking agents, dissolution promoters, and the like can be further added as necessary in addition to the components (A) to (C) of the present application. As the other resins used here, the same resins as those which can be used in the composition for an underlayer film for a resist can be mentioned.

[0139] As to the method of the photolithography using the resist permanent film composition, for example, the other resin component and the additive component are dissolved and dispersed in the positive photosensitive resin composition of the present application, coated on the object to be subjected to the photolithography, and subjected to pre-baking at a temperature of 60 to 150°C. The coating method at this time can be any of spin coating, roll coating, flow coating, dip coating, spray coating, doctor blade coating, and the like. Next, the target resist pattern is exposed through a predetermined mask, and the exposed portions are dissolved with an alkali developer, whereby a resist pattern is formed.

[0140] The resist permanent film of the present embodiment is suitably used for, for example, in semiconductor device-related applications, a solder resist, a packaging material, an underfill material, a packaging adhesive layer of a circuit element, an adhesive layer of an integrated circuit element and a circuit substrate, and in thin display-related applications typified by an LCD and an OLED, a thin film transistor protective film, a liquid crystal color filter protective film, a black matrix, a spacer, and the like.

[0141] [Examples]

[0142] Hereinafter, the present application will be further explained in detail by citing specific examples. Note that the weight average molecular weight (Mw) of the synthesized resin is measured under the following GPC measurement conditions.

[0143] [GPC Measurement Conditions]

[0144] Measurement device: "HLC-8220 GPC" manufactured by Tosoh Corporation

[0145] Column: "Shodex KF802" manufactured by Showa Denko K.K.: 8.0 mmΦ x 300 mm

[0146] + "Shodex KF802" manufactured by Showa Denko K.K.: 8.0 mmΦ x 300 mm

[0147] + "Shodex KF803" manufactured by Showa Denko K.K.: 8.0 mmΦ x 300 mm

[0148] + "Shodex KF804" manufactured by Showa Denko K.K.: 8.0 mmΦ x 300 mm

[0149] Column temperature: 40°C

[0150] Detector: RI (differential refractometer)

[0151] Data processing: "GPC-8020 Model II Version 4.30" manufactured by Tosoh Corporation

[0152] Elution solvent: tetrahydrofuran

[0153] Flow rate: 1.0 mL / min

[0154] Sample: A sample obtained by filtering a tetrahydrofuran solution of 0.5 mass% of the resin solid content with a microfilter

[0155] Injection amount: 0.1 mL

[0156] Standard sample: The following monodisperse polystyrene

[0157] (Standard sample: monodisperse polystyrene)

[0158] "A-500" manufactured by DOW CORP.

[0159] "A-2500" manufactured by DOW CORP.

[0160] "A-5000" manufactured by DOW CORP.

[0161] "F-1" manufactured by DOW CORP.

[0162] "F-2" manufactured by DOW CORP.

[0163] "F-4" manufactured by DOW CORP.

[0164] "F-10" manufactured by DOW CORP.

[0165] "F-20" manufactured by DOW CORP.

[0166] Synthesis Example 1 (Synthesis of Novolak-type phenolic resin (A-1) having an acetal group-based protecting group)

[0167] Into a 2000 ml four-necked flask equipped with a condenser tube, 164 g (1.52 mol) of m-cresol, 95.5 g (0.90 mol) of benzaldehyde, 73 g (0.60 mol) of salicylaldehyde, 2.3 g (0.08 mol) of paraformaldehyde, and 8 g of p-toluenesulfonic acid were charged, and dissolved in 300 g of ethanol as a reaction solvent. Then, the reaction was carried out by heating with a mantle heater and stirring at 80°C under reflux for 16 hours. After the reaction, ethyl acetate and water were added, and the liquid was washed 5 times. After removing the solvent from the residual resin solution by distillation under reduced pressure, vacuum drying was performed, and 289 g of a light red powder of the novolak-type phenolic resin (A-1) was obtained.

[0168] Next, in a 500 ml four-necked flask, 80 g of the obtained novolak-type phenolic resin powder (a-1), 8 g of propyl vinyl ether, and 0.1 g of p-toluenesulfonic acid were dissolved in 120 g of methyl isobutyl ketone. The reaction was carried out by heating to 40°C with a sheathed resistance heater and stirring for 4 hours. After the reaction, 0.4 g of dimethylaminoethanol was added, and after sufficient stirring, ethyl acetate and water were added and washed 5 times. After removing the solvent from the residual resin solution by distillation under reduced pressure, vacuum drying was carried out, and 79 g of a light red powder of novolak-type phenolic resin (A-1) was obtained. The weight average molecular weight (Mw) of the novolak-type phenolic resin (A-1) was 3,290, and the number average molecular weight (Mn) was 1,030, as determined by GPC. 13 C-NMR confirmed that the novolak-type phenolic resin (A-1) had an acetal group-based protecting group.

[0169] Synthesis Example 2 (Synthesis of novolak-type phenolic resin (A-2))

[0170] The input amounts of the starting materials were set to m-cresol 164 g (1.52 mol), benzaldehyde 80 g (0.75 mol), salicylaldehyde 92 g (0.75 mol), and paraformaldehyde 2.3 g (0.08 mol), and otherwise the same operations as in Synthesis Example 1 were performed, and 77 g of a novolak-type phenolic resin powder (A-2) having an acetal group-based protecting group was obtained. The Mw of the novolak-type phenolic resin (A-2) was 3,430.

[0171] Synthesis Example 3 (Synthesis of novolak-type phenolic resin (A-3))

[0172] The input amounts of the starting materials were set to m-cresol 164 g (1.52 mol), benzaldehyde 64 g (0.60 mol), salicylaldehyde 110 g (0.90 mol), and paraformaldehyde 2.3 g (0.08 mol), and otherwise the same operations as in Synthesis Example 1 were performed, and 81 g of a novolak-type phenolic resin powder (A-3) having an acetal group-based protecting group was obtained. The Mw of the novolak-type phenolic resin (A-3) was 3,270.

[0173] Synthesis Example 4 (Synthesis of novolak-type phenolic resin (A-4))

[0174] The input amounts of the starting materials were set to m-cresol 164 g (1.52 mol), benzaldehyde 48 g (0.45 mol), salicylaldehyde 128 g (1.05 mol), and paraformaldehyde 2.3 g (0.08 mol), and otherwise the same operations as in Synthesis Example 1 were performed, and 81 g of a novolak-type phenolic resin powder (A-4) having an acetal group-based protecting group was obtained. The Mw of the novolak-type phenolic resin (A-4) was 4,350.

[0175] Synthesis Example 5 (Synthesis of novolak-type phenolic resin (A-5))

[0176] The reaction solvent was changed to methanol, and the reaction temperature was set to 65°C, and otherwise the same procedure as in Synthesis Example 1 was followed to obtain a novolak-type phenolic resin powder having an acetal group-based protecting group (A-5) 82 g. The Mw of the novolak-type phenolic resin (A-5) was 12,170.

[0177] Synthesis Example 6 (Synthesis of a novolak-type phenolic resin (A-6))

[0178] The input amount of the starting material was set to m-cresol 164 g (1.52 mol), benzaldehyde 95.5 g (0.90 mol), salicylaldehyde 73 g (0.60 mol), and paraformaldehyde 0.46 g (0.015 mol), and otherwise the same procedure as in Synthesis Example 1 was followed to obtain a novolak-type phenolic resin powder having an acetal group-based protecting group (A-6) 81 g. The Mw of the novolak-type phenolic resin (A-6) was 3,020.

[0179] Synthesis Example 7 (Synthesis of a novolak-type phenolic resin (A-7))

[0180] The input amount of the starting material was set to m-cresol 164 g (1.52 mol), benzaldehyde 95.5 g (0.90 mol), salicylaldehyde 73 g (0.60 mol), and paraformaldehyde 4.6 g (0.15 mol), and otherwise the same procedure as in Synthesis Example 1 was followed to obtain a novolak-type phenolic resin powder having an acetal group-based protecting group (A-7) 81 g. The Mw of the novolak-type phenolic resin (A-7) was 3,420.

[0181] Synthesis Example 8 (Synthesis of a novolak-type phenolic resin (A-8))

[0182] The input amount of the starting material was set to m-cresol 164 g (1.52 mol), benzaldehyde 95.5 g (0.90 mol), salicylaldehyde 73 g (0.60 mol), and paraformaldehyde 9.2 g (0.31 mol), and otherwise the same procedure as in Synthesis Example 1 was followed to obtain a novolak-type phenolic resin powder having an acetal group-based protecting group (A-8) 83 g. The Mw of the novolak-type phenolic resin (A-8) was 3,720.

[0183] Comparative Synthesis Example 1 (Synthesis of a novolak-type phenolic resin (A-9))

[0184] The starting materials were charged so as to be m-cresol 164 g (1.52 mol), benzaldehyde 95.5 g (0.90 mol), and salicylaldehyde 73 g (0.60 mol), and the same operation as in Synthesis Example 1 was performed except for this to obtain a phenol novolak-type phenol formaldehyde resin powder (A-9) 83 g having an acetal group-based protecting group. The Mw of the phenol novolak-type phenol formaldehyde resin (A-9) was 2,990.

[0185] Comparative Synthesis Example 2 (synthesis of a phenol novolak-type phenol formaldehyde resin (A-10))

[0186] The starting materials were charged so as to be m-cresol 164 g (1.52 mol), benzaldehyde 95.5 g (0.90 mol), salicylaldehyde 73 g (0.60 mol), and paraformaldehyde 13.8 g (0.46 mol), and the same operation as in Synthesis Example 1 was performed except for this to obtain a phenol novolak-type phenol formaldehyde resin (A-10) powder 82 g having an acetal group-based protecting group. The Mw of the phenol novolak-type phenol formaldehyde resin (A-10) was 3,690.

[0187] [Positive photosensitive resin composition]

[0188] Example 1

[0189] A phenol novolak-type phenol formaldehyde resin (A-1) powder 1.98 g obtained in Synthesis Example 1, a photoacid generator (San-Apro Co., Ltd.: CPI-110TF) 0.02 g were dissolved in propylene glycol monomethyl ether (PGME) 8 g, and a 0.1 μm PTFE disk filter was used to perform precision filtration, to obtain a positive photosensitive resin composition (solid content concentration 20%).

[0190] Examples 2 to 8, Comparative Examples 1 and 2

[0191] A positive photosensitive resin composition was prepared using the phenol novolak-type phenol formaldehyde resin shown in Table 1 as component (A), and the same operation as in Example 1 was performed except for this.

[0192] [Evaluation]

[0193] A resist film was produced using the positive photosensitive resin composition prepared in the examples and comparative examples, and the alkali solubility, development contrast, and heat resistance of the resist film were evaluated. Furthermore, the storage stability and thick film formability of the positive photosensitive resin composition were evaluated. The results are shown in Table 1.

[0194] (1) Alkali development property

[0195] A positive photosensitive resin composition was applied to a 5-inch silicon wafer with a spin coater at a thickness of about 1 μm, dried on a hot plate at 110°C for 60 seconds to obtain a resist film. Then, the resist film was exposed to 200 mJ / cm2using a UV exposure device (San-Ei Electric Co., Ltd.: UV E-1001SD), and after exposure, post-exposure baking (PEB) was performed on a hot plate at 130°C for 90 seconds. The obtained 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 film thickness of the resist film before and after immersion in the developer was measured, and the value obtained by dividing the difference by 60 was taken as the alkali solubility ADR1 2 The evaluation criteria are described below. The evaluation criteria are described below.

[0196] O: ADR1 is 200 or more

[0197] X: ADR1 is less than 200

[0198] In Table 1, the values in parentheses are the values of ADR1.

[0199] (2) Development contrast

[0200] In the above (1), the value measured similarly without performing exposure of the resist film was taken as ADR2 The value of ADR1 / ADR2 was taken as the development contrast. The evaluation criteria are described below.

[0201] O: Development contrast is 50 or more

[0202] X: Development contrast is less than 50

[0203] In Table 1, the values in parentheses are the values of ADR1 / ADR2.

[0204] (3) Heat resistance

[0205] A positive photosensitive resin composition was applied to a 5-inch silicon wafer using a spin coater, and dried at 110°C for 60 seconds to obtain a 1-μm-thick film. The film was scraped off, and the glass transition temperature (hereinafter abbreviated as "Tg") was measured. Note that, for the measurement of Tg, a differential scanning calorimeter (TA Instruments, Inc.: differential scanning calorimeter (DSC) Q100) was used under the conditions of a nitrogen atmosphere, a temperature range of -100 to 200°C, and a temperature increase rate of 10°C / minute.

[0206] The evaluation criteria are described below.

[0207] O: Tg is 140°C or more

[0208] X: Tg is less than 140°C

[0209] In Table 1, the values in parentheses are values of Tg.

[0210] (4) Storage stability

[0211] The change rate of ADR2 in the above (2) was evaluated. The positive photosensitive resin composition having poor storage stability has a rapid change in ADR2 due to the progress of the dissociation of the protective group. Specifically, the positive photosensitive resin composition was stored at ordinary temperature for one month, and the storage stability was evaluated using the following formula based on ADR2 before and after storage.

[0212] ADR2 change rate = (ADR2 after storage / ADR2 before storage) x 100

[0213] The evaluation criteria are described below.

[0214] ◎: ADR2 change rate is less than 150%

[0215] O: ADR2 change rate is less than 200%

[0216] X: ADR2 change rate is 200% or more

[0217] In Table 1, the values in parentheses are values of ADR2 change rate (%).

[0218] (5) Thick film formability

[0219] A positive photosensitive resin composition was applied to a 5-inch silicon wafer at a thickness of about 5 μm using a spin coater, and dried on a hot plate at 110°C for 60 seconds to form a resist film. The resist film was observed using an optical microscope, and the formability was evaluated based on the presence or absence of cracks.

[0220] The evaluation criteria are described below.

[0221] O: No cracks

[0222] X: Cracks are present [Table 1]

[0223]

[0224] *In Examples 1 and 5, the solvent used in the synthesis of component (A) was different.

[0225] In Table 1, "Cr" means cresol, "SA" means salicylaldehyde, "BA" means benzaldehyde, and "FA" means formaldehyde.

[0226] For example, "m-Cr / BA / SA / FA" of Example 1, which is "1 / 0.59 / 0.4 / 0.05", means that the novolak type phenol-aldehyde resin of Example 1 as the (A) component is composed of units derived from m-cresol, units derived from benzaldehyde, units derived from salicylaldehyde, and units derived from formaldehyde, and the molar ratio (units derived from m-cresol: units derived from benzaldehyde: units derived from salicylaldehyde: units derived from formaldehyde) satisfies 1:0.59:0.4:0.05.

[0227] As shown in Table 1, the positive photosensitive resin composition of the present application is excellent in storage stability and thick film formability. In addition, it is known that the resist film using the positive photosensitive resin composition of the present application is excellent in alkali solubility, development contrast, and heat resistance.

Claims

1. A positive photosensitive resin composition comprising the following components (A) to (C), (A) a phenol novolak type phenol resin having a molar ratio of structural units derived from m-cresol (al), structural units derived from benzaldehyde (a2), structural units derived from salicylaldehyde (a3), and structural units derived from formaldehyde (a4), i.e., (al):(a2):(a3):(a4) = 1.0:0.3 to 0.8:0.3 to 0.8:0.01 to 0.2, and an acetal-based protecting group, (B) a photo-acid generator, (C) a solvent.

2. The positive photosensitive resin composition according to claim 1, wherein the acetal-based protecting group is a group represented by the following formula (1), in the formula, R1 and R2 are each independently a hydrogen atom, a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, or an aryl group having a carbon number of 6 to 20, R3 is a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 20, or an aralkyl group having a carbon number of 7 to 20, and R3 can combine with R1 or R2 to form a ring, * which binds to a benzene ring constituting a main chain of the phenol novolak type phenol resin.

3. The positive photosensitive resin composition according to claim 1, wherein the component (A) is obtained by reacting a phenol novolak type phenol resin obtained by polycondensing m-cresol, benzaldehyde, salicylaldehyde, and formaldehyde in an organic solvent in a molar ratio of m-cresol:benzaldehyde:salicylaldehyde:formaldehyde = 1.0:0.3 to 0.8:0.3 to 0.8:0.01 to 0.2 with an acid catalyst, with a compound forming an acetal-based protecting group.

4. The positive photosensitive resin composition according to claim 3, wherein the compound forming the acetal-based protecting group is a compound represented by the following formula (2), in the formula, R3 is a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, an aryl group having a carbon number of 6 to 20, or an aralkyl group having a carbon number of 7 to 20, R4 to R6 are each independently a hydrogen atom, a linear alkyl group having a carbon number of 1 to 20, a branched alkyl group having a carbon number of 3 to 20, a cyclic alkyl group having a carbon number of 3 to 20, or an aryl group having a carbon number of 6 to 20.

5. The positive photosensitive resin composition according to claim 3, wherein the compound forming the acetal-based protecting group is propyl vinyl ether.

6. The positive photosensitive resin composition according to claim 1, wherein the content of the structural units derived from m-cresol (al), the structural units derived from benzaldehyde (a2), the structural units derived from salicylaldehyde (a3), and the structural units derived from formaldehyde (a4) in the component (A) is 30 mass% or more in total.

7. A photosensitive film obtained by drying the positive photosensitive resin composition according to any one of claims 1 to 6.

8. A resist film obtained from the positive photosensitive resin composition according to any one of claims 1 to 6.

9. A resist underlayer film obtained from the positive photosensitive resin composition according to any one of claims 1 to 6.

10. A resist permanent film obtained from the positive photosensitive resin composition according to any one of claims 1 to 6.

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