Phenolic hydroxyl group-containing resin, photosensitive resin composition, curable composition and resist film

Abstract

To provide a photosensitive resin composition which has excellent solubility in a weakly alkaline developer and a high affinity for a photosensitizer and does not use formaldehyde.SOLUTION: A phenolic hydroxyl group-containing resin contains a structural unit (a) derived from a phenol compound, a structural unit (b) derived from an aliphatic aldehyde compound having a carboxyl group, and a structural unit (c) derived from an aromatic aldehyde compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a phenolic hydroxyl group-containing resin, and a photosensitive resin composition, a curable composition, and a resist film each using the same. [Background technology]

[0002] Positive photosensitive resin compositions containing alkali-soluble resins and photosensitizers such as 1,2-naphthoquinone diazide compounds are known as resists used in the manufacture of semiconductors such as ICs and LSIs, display devices such as LCDs, and printing original plates. In the field of photoresists, a wide variety of resist pattern formation methods, each subdivided according to application and function, are being developed one after another, and as a result, the performance requirements for resist resin materials are becoming more sophisticated and diversified.

[0003] Although tetramethylammonium hydroxide is widely used as a developer for positive-type photosensitive resin compositions, it is highly toxic and has a large environmental impact. In recent years, in order to reduce the environmental impact, there has been a demand for positive-type photosensitive resin compositions that can be developed with weakly alkaline developers with low environmental impact, such as sodium carbonate or sodium bicarbonate, and that do not contain environmentally hazardous substances such as formaldehyde. Furthermore, with the increasing integration density of semiconductors and the trend toward thinner patterns, there is a demand for better sensitivity.

[0004] To address the above-mentioned problems, for example, Patent Document 1 discloses a positive photosensitive resin composition that can be developed with a weak alkaline developer, which is a combination of a phenolic resin having a carboxylic acid and a naphthoquinone diazide photosensitizer.

[0005] On the other hand, a known method for producing an electrode pattern made of a transparent conductive film on a transparent substrate is to form a photosensitive layer containing a positive photosensitive resin composition on a transparent conductive film formed on a substrate, expose the photosensitive layer through a mask, and develop the photosensitive layer to remove the photosensitive layer in the exposed areas, etch the exposed transparent conductive film, and remove the remaining photosensitive layer.

[0006] In recent years, due to the depletion of In, the use of ZnO or ZnO with metals added (hereinafter referred to as "ZnO-based films") has been considered in place of ITO in the transparent conductive films used in electrodes. It is known that ZnO-based films are damaged by strong alkalis, and therefore practical electrode patterns cannot be produced using conventional strong alkaline developers. For this reason, the development of positive-type photosensitive resin compositions that can produce fine electrode patterns using weak alkaline developers such as sodium carbonate or sodium bicarbonate, which do not damage ZnO-based films, has also been considered (e.g., Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-114853 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-112134 Summary of the Invention [Problem to be solved by the invention]

[0008] The positive photosensitive resin composition described in Patent Document 1 does not provide a sufficient dissolution rate in a weak alkaline developer, and does not provide sensitivity suitable for miniaturization. Furthermore, since various heat treatments are performed in the manufacturing process of semiconductors and the like, high heat resistance is also required, but the positive photosensitive resin composition described in Patent Document 1 has the problem of not having sufficient heat resistance. The positive photosensitive resin composition described in Patent Document 2 does not provide a sufficient dissolution rate in a weak alkaline developer, and has poor affinity with photosensitizers, making it unsuitable for drawing fine patterns. The positive photosensitive resin compositions described in Patent Documents 1 and 2 both have the problem of using formaldehyde, an environmentally hazardous substance.

[0009] As described above, from the viewpoint of reducing the environmental load and for fabricating fine electrode patterns on ZnO-based films, there is a need for the development of a positive-tone photosensitive resin composition that exhibits excellent solubility in a weak alkaline developer, has high affinity with photosensitizers, has high heat resistance, and does not contain environmentally hazardous substances such as formaldehyde.

[0010] An object of the present invention is to provide a photosensitive resin composition which has excellent solubility in a weak alkaline developer and high affinity with a photosensitizer, and which does not contain formaldehyde. Another object of the present invention is to provide a curable material that can give a resist film having high heat resistance. [Means for solving the problem]

[0011] The present inventors conducted extensive research to solve the above problems and discovered that a composition using a phenolic hydroxyl group-containing resin containing a structural unit (a) derived from a phenolic compound, a structural unit (b) derived from an aliphatic aldehyde compound having a carboxyl group, and a structural unit (c) derived from an aromatic aldehyde compound has excellent solubility in weak alkaline developers and high affinity with photosensitizers, thereby completing the present invention. The phenolic hydroxyl group-containing resin is synthesized without using formaldehyde.

[0012] That is, the present invention relates to a phenolic hydroxyl group-containing resin comprising a structural unit (a) derived from a phenol compound, a structural unit (b) derived from an aliphatic aldehyde compound having a carboxyl group, and a structural unit (c) derived from an aromatic aldehyde compound. The present invention also relates to a photosensitive resin composition containing the phenolic hydroxyl group-containing resin and a quinone diazide photosensitizer. The present invention also relates to a resist film obtained from the photosensitive resin composition. The present invention also relates to a curable composition containing the phenolic hydroxyl group-containing resin and a curing agent. The present invention also relates to a cured product of the curable composition. The present invention also relates to a method for producing a resist pattern, comprising: a coating film forming step of forming a coating film made of the photosensitive resin composition on a substrate; an exposure step of exposing the coating film to light; and a development step of developing the coating film after the exposure step with a dilute, weakly alkaline developer. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a photosensitive resin composition which has excellent solubility in a weak alkaline developer, high affinity with a photosensitizer, and does not contain formaldehyde. Furthermore, it is possible to provide a curable material that can give a resist film having high heat resistance. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a GPC chart of the phenolic hydroxyl group-containing resin obtained in Example 1. [Figure 2] 1 is a C-NMR chart of the phenolic hydroxyl group-containing resin obtained in Example 1. [Figure 3] 1 is a GPC chart of the phenolic hydroxyl group-containing resin obtained in Example 2. [Figure 4] 1 is a C-NMR chart of the phenolic hydroxyl group-containing resin obtained in Example 2. [Figure 5] 1 is a C-NMR chart of the phenolic hydroxyl group-containing resin obtained in Comparative Synthesis Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[0016] [Phenol hydroxyl group-containing resin] A phenolic hydroxyl group-containing resin according to one embodiment of the present invention contains the following structural units (a) to (c). Structural unit (a): A structural unit derived from a phenolic compound Structural unit (b): a structural unit derived from an aliphatic aldehyde compound having a carboxyl group Structural unit (c): a structural unit derived from an aromatic aldehyde compound (having no carboxyl group)

[0017] The structural unit (a) contributes to the affinity and heat resistance of the photosensitizer, the structural unit (b) contributes to the solubility in a weak alkaline developer and heat resistance, and the structural unit (c) contributes to the affinity and heat resistance of the photosensitizer.

[0018] In this embodiment, the abundance ratio of the structural units (a), (b), and (c) (molar ratio, structural units (a):structural units (b):structural units (c)) is preferably 0.5-1.5:0.05-1.0:0.1-1.5, more preferably 1.0:0.05-1.0:0.1-1.5, and particularly preferably 1.0:0.1-0.6:0.3-1.2. The ratio of the components can be adjusted by adjusting the ratio of the raw material compounds.

[0019] Regarding the structural unit (a), the phenol compound is preferably a compound represented by the following formula (1). [ka] (In formula (1), R1 represents an aliphatic hydrocarbon group, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom. 1 represents an integer of 0 to 2, and m represents 1 or 2.)

[0020] The aliphatic hydrocarbon group of R1 in the above formula (1) includes alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and cyclohexyl groups. The number of carbon atoms is preferably 1 to 9. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and a cyclohexyloxy group.The number of carbon atoms is preferably 1 to 9, for example.

[0021] Examples of aryl groups include those having 6 to 14 carbon atoms forming a ring. The aryl group may have a substituent such as the above-mentioned alkyl group, alkoxy group, or hydroxy group. Specific examples include a phenyl group, a hydroxyphenyl group, a dihydroxyphenyl group, a hydroxyalkoxyphenyl group, an alkoxyphenyl group, a tolyl group, a xylyl group, a naphthyl group, a hydroxynaphthyl group, and a dihydroxynaphthyl group.

[0022] 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 above-mentioned alkyl group and alkoxy group, or a hydroxy group. Specific examples include a phenylmethyl group, a hydroxyphenylmethyl group, a dihydroxyphenylmethyl 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. Examples of halogen atoms include fluorine atoms, chlorine atoms, and bromine atoms.

[0023] In one embodiment, R1 is an aliphatic hydrocarbon group having 1 to 4 carbon atoms, preferably a methyl group. Furthermore, l is preferably 1.

[0024] Specific examples include monoalkylphenols such as o-cresol, m-cresol, p-cresol, o-ethylphenol, m-ethylphenol, p-ethylphenol, p-octylphenol, pt-butylphenol, o-cyclohexylphenol, m-cyclohexylphenol, and p-cyclohexylphenol; and dialkylphenols such as 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, 2,4-xylenol, and 2,6-xylenol. Of these, monoalkylphenols are preferred, and o-cresol, m-cresol, and p-cresol are more preferred.

[0025] The phenol compound may be a single compound having the same structure, or a plurality of compounds having different molecular structures may be used.

[0026] Regarding the structural unit (b), the aliphatic aldehyde compound having a carboxyl group is preferably a compound represented by the following formula (2). [ka] (In formula (2), R is a single bond or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.)

[0027] In formula (2), the alkylene group having 1 to 20 carbon atoms may be linear or branched. The alkylene group may have a substituent, provided that the effect of the present invention is not impaired. Examples of the substituent include a halogen atom, an alkoxy group, an aryl group, an arylalkyl group, a silyl group, an acyl group, an acyloxy group, a carboxy group, a sulfo group, a cyano group, a nitro group, a hydroxy group, a mercapto group, an alkylthio group, and an oxo group.

[0028] Examples of the alkylene group having 1 to 20 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an ethylpropylene group, an n-butylene group, an isobutylene group, an ethylbutylene group, an n-pentylene group, an isopentylene group, an ethylpentylene group, an n-hexylene group, an isohexylene group, and an ethylhexylene group. R is preferably a single bond or an unsubstituted alkylene group having 1 to 20 carbon atoms, and more preferably a single bond or an unsubstituted alkylene group having 1 to 10 carbon atoms.

[0029] Specific examples of the compound represented by formula (2) include glyoxylic acid (R is a single bond), 2-formylacetic acid, 2-formylpropionic acid, 4-oxobutyric acid, 5-oxovaleric acid, etc. Among these, glyoxylic acid is preferred. The aliphatic aldehyde having a carboxyl group may be used alone or in combination of two or more kinds.

[0030] Regarding the structural unit (c), in this embodiment, the aromatic aldehyde compound is preferably a compound represented by the following formula (3). [ka] (In formula (3), R3 is a group selected from the group consisting of an aliphatic hydrocarbon group, an alkoxy group, a halogen atom, a cyano group, and a nitro group, n is an integer of 0 to 3, and p is an integer of 0 to 2.)

[0031] The aliphatic hydrocarbon group of R3 in the above formula (3) includes alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and cyclohexyl groups. The number of carbon atoms is preferably 1 to 9, and more preferably 1 to 5. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propyloxy group, a butoxy group, a pentyloxy group, a hexyloxy group, and a cyclohexyloxy group. The number of carbon atoms is preferably 1 to 9, and more preferably 1 to 5.

[0032] n is an integer of 0 to 3, with 0 or 1 being preferred. p is an integer of 0 to 2, and 0 or 1 is preferred.

[0033] Examples of aromatic aldehydes include salicylaldehyde, benzaldehyde, 2-chlorobenzaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 2-methoxybenzaldehyde, and 3-nitrobenzaldehyde. The aromatic aldehyde is preferably salicylaldehyde or benzaldehyde. One type of aromatic aldehyde may be used alone, or two or more types may be used in combination. In one embodiment, the aromatic aldehyde preferably has a hydroxyl group in the ortho position relative to the carbonyl group.

[0034] In the phenolic hydroxyl group-containing resin according to this embodiment, the total content of the structural units (a), (b), and (c) is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 90% by mass or more, in view of excellent solubility in a weak alkaline developer and high affinity with the photosensitizer. The total content of the structural units (a), (b), and (c) may be substantially 100% by mass, which means that structural units other than the structural units (a), (b), and (c) are inevitably contained.

[0035] The weight-average molecular weight of the phenolic hydroxyl group-containing resin according to this embodiment is preferably 1,000 or more, more preferably 1,500 or more. It is also preferably 10,000 or less, more preferably 9,000 or less, and even more preferably 8,000 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 8,000 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.

[0036] The phenolic hydroxyl group-containing resin according to this embodiment can be obtained by polycondensing the above-mentioned phenol compound, aliphatic aldehyde compound having a carboxyl group, and aromatic aldehyde compound in a solvent using an acid catalyst.

[0037] The molar ratio of the phenol compound, the aliphatic aldehyde compound having a carboxyl group, and the aromatic aldehyde compound in the solvent (phenol compound:aliphatic aldehyde compound having a carboxyl group:aromatic aldehyde compound) is preferably in the range of 1.0:0.05 to 1.0:0.1 to 1.5, and more preferably 1.0:0.1 to 0.6:0.3 to 1.2, from the viewpoint of obtaining a cured film having excellent solubility in a weak alkaline developer and heat resistance.

[0038] The ratio of the total mass of the phenol compound, the aliphatic aldehyde compound having a carboxyl group, and the aromatic aldehyde compound in the solvent to the total mass of the starting materials for the phenolic hydroxyl group-containing resin is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably substantially 100% by mass, from the viewpoint of obtaining a cured film that is heat resistant in addition to being soluble in a weak alkaline developer.

[0039] Examples of acid catalysts include acetic acid, oxalic acid, sulfuric acid, hydrochloric acid, phenolsulfonic acid, paratoluenesulfonic acid, zinc acetate, and manganese acetate. These acid catalysts can be used alone or in combination of two or more. Sulfuric acid and paratoluenesulfonic acid are preferred because of their excellent activity. The acid catalyst may be added before or during the reaction.

[0040] Examples of solvents used in the production of phenolic hydroxyl group-containing resins include carboxylic acid compounds such as formic acid, acetic acid, propionic acid, butyric acid, and valeric acid; glycol ether compounds such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl methyl ether, and ethylene glycol monophenyl ether; cyclic ether compounds such as 1,3-dioxane and 1,4-dioxane; glycol ester compounds such as ethylene glycol acetate; ketone compounds such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and aromatic hydrocarbons such as toluene and xylene. These solvents can be used alone or in combination. Acetic acid is preferred because of its excellent solubility in the resulting compound.

[0041] From the viewpoint of uniformity of the reaction, the amount of the 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 material for the phenolic hydroxyl group-containing resin, and is preferably 500 parts by mass or less, more preferably 300 parts by mass or less.

[0042] The reaction temperature during polycondensation of the raw materials for the phenolic hydroxyl group-containing resin 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.

[0043] After the reaction is completed, the product is recovered, for example, by reprecipitation, to obtain a phenolic hydroxyl group-containing resin. Examples of poor solvents used in the reprecipitation operation include water, monoalcohols such as methanol, ethanol, and propanol, aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, and cyclohexane, and aromatic hydrocarbons such as toluene and xylene. Among these poor solvents, water and methanol are preferred because they allow efficient removal of the acid catalyst at the same time.

[0044] In order to increase the purity of the phenolic hydroxyl group-containing resin, the reprecipitation operation may be carried out two or more times. In this case, examples of the solvent for dissolving the phenolic hydroxyl group-containing resin include monoalcohols such as methanol, ethanol, and propanol; polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, trimethylene glycol, diethylene glycol, polyethylene glycol, and glycerin; glycol ethers such as 2-ethoxyethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl methyl ether, and ethylene glycol monophenyl ether; cyclic ethers such as 1,3-dioxane and 1,4-dioxane; glycol esters such as ethylene glycol acetate; and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. When water is used as the poor solvent, the solvent for redissolving is preferably acetone. The poor solvent and the solvent may each be used alone or in combination of two or more kinds.

[0045] The phenolic hydroxyl group-containing resin of the present invention can be used in a variety of electrical and electronic materials such as adhesives, paints, photoresists, and printed wiring boards.

[0046] [Photosensitive resin composition] A photosensitive resin composition according to one embodiment of the present invention contains the phenolic hydroxyl group-containing resin of the present invention (hereinafter sometimes referred to as phenolic hydroxyl group-containing resin (A)) and a quinone diazide-based photosensitizer (hereinafter sometimes referred to as photosensitizer (B)). The phenolic hydroxyl group-containing resin (A) has high affinity with the quinone diazide-based photosensitizer, resulting in a highly sensitive photosensitive resin composition.

[0047] The amount of the phenolic hydroxyl group-containing resin (A) in the photosensitive resin composition of this embodiment is preferably in the range of 50 to 99 mass %, more preferably in the range of 60 to 95 mass %, and even more preferably in the range of 70 to 90 mass %, based on the total resin solid content of the photosensitive resin composition.

[0048] The quinone diazide photosensitizer (B) includes a compound having a quinone diazide group. Specific examples of the compound having a quinone diazide group include a complete ester compound, a partial ester compound, an amidation product, or a partial amidation product of an aromatic (poly)hydroxy compound and a sulfonic acid having a quinone diazide group, such as naphthoquinone-1,2-diazide-5-sulfonic acid, naphthoquinone-1,2-diazide-4-sulfonic acid, or orthoanthraquinone diazide sulfonic acid.

[0049] Examples of aromatic (poly)hydroxy compounds include polyhydroxybenzophenone compounds such as 2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,3,6-trihydroxybenzophenone, 2,3,4-trihydroxy-2'-methylbenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,3',4,4',6-pentahydroxybenzophenone, 2,2',3,4,4'-pentahydroxybenzophenone, 2,2',3,4,5-pentahydroxybenzophenone, 2,3',4,4',5',6-hexahydroxybenzophenone, and 2,3,3',4,4',5'-hexahydroxybenzophenone;

[0050] bis[(poly)hydroxyphenyl]alkane compounds such as bis(2,4-dihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)methane, 2-(4-hydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(2',4'-dihydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(2',3',4'-trihydroxyphenyl)propane, 4,4'-{1-[4-[2-(4-hydroxyphenyl)-2-propyl]phenyl]ethylidene}bisphenol, and 3,3'-dimethyl-{1-[4-[2-(3-methyl-4-hydroxyphenyl)-2-propyl]phenyl]ethylidene}bisphenol;

[0051] tris(hydroxyphenyl)methane compounds or methyl-substituted compounds thereof, such as tris(4-hydroxyphenyl)methane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, and bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane;

[0052] Bis(3-cyclohexyl-4-hydroxyphenyl)-3-hydroxyphenylmethane, Bis(3-cyclohexyl-4-hydroxyphenyl)-2-hydroxyphenylmethane, Bis(3-cyclohexyl-4-hydroxyphenyl)-4-hydroxyphenylmethane, Bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-2-hydroxyphenylmethane, Bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-3-hydroxyphenylmethane, Bis(5-cyclohexyl-4-hydroxy-2 -methylphenyl)-4-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-3-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-4-hydroxy phenylmethane, bis(3-cyclohexyl-2-hydroxyphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-2-hydroxy-4-methylphenyl)-4-hydroxyphenylmethane, and the like, and bis(cyclohexylhydroxyphenyl)(hydroxyphenyl)methane compounds and methyl-substituted derivatives thereof. These photosensitizers may be used alone or in combination of two or more.

[0053] The amount of the photosensitizer (B) in the photosensitive resin composition of this embodiment is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total resin solid content of the photosensitive resin composition, in order to obtain a photosensitive resin composition with excellent photosensitivity, and is preferably 50% by mass or less, more preferably 30% by mass or less.

[0054] The photosensitive resin composition of the present embodiment preferably further contains a phenolic resin having a calix structure containing a structural unit (a) derived from a phenolic compound and a structural unit (b) derived from an aliphatic aldehyde compound having a carboxyl group (hereinafter, sometimes referred to as a phenolic hydroxyl group-containing resin (C)).

[0055] The phenolic hydroxyl group-containing resin (C) is a phenolic hydroxyl group-containing resin represented by the following general formula (C).

[0056] [ka] (In the general formula (C), R 21 is an alkyl group, an alkoxy group, or an aryl group, R 22 is a carboxyl group or an alkyl group having 1 to 20 carbon atoms and having a carboxyl group, p is an integer of 1 to 3, and q is an integer of 2 to 15. If p is 2 or more, multiple R 21 may be the same or different.)

[0057] The phenolic hydroxyl group-containing resin (C) can be obtained by polycondensing the phenolic compound and the aliphatic aldehyde compound having a carboxyl group described in the phenolic hydroxyl group-containing resin (A) in a solvent using an acid catalyst.

[0058] The weight average molecular weight of the phenolic hydroxyl group-containing resin (C) is preferably 1,000 or more, more preferably 1,500 or more, and preferably 25,000 or less, more preferably 20,000 or less, and even more preferably 10,000 or less.

[0059] The amount of the phenolic hydroxyl group-containing resin (C) in the photosensitive resin composition of this embodiment is, for example, in the range of 5 to 20 mass %, preferably in the range of 5 to 15 mass %, more preferably in the range of 7 to 15 mass %, and even more preferably in the range of 10 to 13 mass %, relative to the total resin solid content of the photosensitive resin composition.

[0060] When the photosensitive resin composition of this embodiment is used for photoresist applications, a resist resin composition can be prepared by adding various additives, such as other phenolic hydroxyl group-containing compounds, pigments, dyes, surfactants such as leveling agents, fillers, crosslinking agents, dissolution promoters, curing agents, and curing accelerators, as needed, in addition to the phenolic hydroxyl group-containing resin (A), photosensitizer (B), and optional phenolic hydroxyl group-containing resin (C), and dissolving them in an organic solvent. The resist resin composition may be used directly as a positive resist solution, or the resist resin composition may be applied to a film and then desolvated to be used as a positive resist film. Examples of the support film used as a resist film include synthetic resin films such as polyethylene, polypropylene, polycarbonate, and polyethylene terephthalate. The support film may be a single-layer film or a laminate film. The surface of the support film may be corona-treated or coated with a release agent.

[0061] Examples of organic solvents 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 organic solvents can be used alone or in combination of two or more.

[0062] The content of the organic solvent in the photosensitive resin composition is preferably adjusted so that the solid content in the composition is 5% by mass or more and 65% by mass or less, which provides sufficient fluidity for the photosensitive resin composition and allows a uniform coating film to be obtained by a coating method such as spin coating.

[0063] The other phenolic hydroxyl group-containing compound may be any phenolic hydroxyl group-containing compound other than the phenolic hydroxyl group-containing resin (A) and the phenolic hydroxyl group-containing resin (C). Examples of other phenolic hydroxyl group-containing compounds include phenolic hydroxyl group-containing compounds such as phenol, cresol, naphthol, biphenol, bisphenol, and triphenylmethane, and phenolic resins such as phenol novolac resin, cresol novolac resin, and bisphenol novolac. These may be used alone or in combination.

[0064] The proportion of the phenolic hydroxyl group-containing resin (A) to the total of the phenolic hydroxyl group-containing resin (A), the phenolic hydroxyl group-containing resin (C), and the other phenolic hydroxyl group-containing compound is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0065] The photosensitive resin composition of the present embodiment can be prepared by stirring and mixing the phenolic hydroxyl group-containing resin (A), the photosensitizer (B), and the organic solvent, and further adding various additives as needed, in a conventional manner to form a homogeneous liquid.

[0066] When solid materials such as fillers and pigments are blended into the photosensitive resin 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.

[0067] [Curable composition] A curable composition according to one embodiment of the present invention contains the above-described phenolic hydroxyl group-containing resin (A) of the present invention and a curing agent. The curing agent used in this embodiment is not particularly limited as long as it is a compound that can undergo a curing reaction with the phenolic hydroxyl group-containing resin of the present invention, and various compounds can be used. Furthermore, the curing method for the curable composition is not particularly limited, and curing can be performed by an appropriate method, such as thermal curing or photocuring, depending on the type of curing agent and the type of curing accelerator. The curing conditions, such as the heating temperature and time for thermal curing and the type of light and exposure time for photocuring, are appropriately adjusted depending on the type of curing agent and the type of curing accelerator, which will be described later.

[0068] Examples of the curing agent used in this embodiment include urea resin, melamine resin, furan resin, xylene resin, epoxy resin, unsaturated polyester resin, thermosetting polyimide, and thermosetting polyamideimide. In one embodiment, a curing accelerator may be blended together with the curing agent. A known or commonly used curing accelerator capable of accelerating the curing reaction can be used depending on the curing agent used. When such a curing agent or curing accelerator is used, a resist film with higher heat resistance can be obtained by forming a resist pattern by the method described below and then heating the resist film.

[0069] The amount of the curing agent in the curable composition of the present embodiment is preferably 0.5 to 50 parts by mass per 100 parts by mass of the total of the phenolic hydroxyl group-containing resin of the present invention and the other resin (X) described below, in order to obtain a composition with excellent curability.

[0070] In addition to the phenolic hydroxyl group-containing resin (A) and the curing agent, the curable composition of this embodiment may contain, as needed, the photosensitizer (B) described above in connection with the photosensitive resin composition of the present invention, other phenolic hydroxyl group-containing compounds, pigments, dyes, surfactants such as leveling agents, various additives such as fillers, crosslinking agents, and dissolution promoters, and organic solvents. Examples of the various additives and organic solvents are the same as those for the photosensitive resin composition described above.

[0071] In one embodiment, the curable composition may contain, in addition to the phenolic hydroxyl group-containing resin of the present invention, another resin (X). Examples of the resin (X) 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 (Xylok resins), naphthol aralkyl resins, trimethylolmethane resins, tetraphenylolethane resins, biphenyl-modified phenolic resins, biphenyl-modified naphthol resins, aminotriazine-modified phenolic resins, and various vinyl polymers.

[0072] When other resin (X) is used, the blending ratio of the phenolic hydroxyl group-containing resin of the present invention to the resin (X) can be set arbitrarily depending on the application. For example, the blending ratio of the resin (X) is preferably 0.5 to 100 parts by mass per 100 parts by mass of the phenolic hydroxyl group-containing resin of the present invention.

[0073] The curable composition of the present embodiment can be prepared by stirring and mixing the phenolic hydroxyl group-containing resin (A), the curing agent, the organic solvent, and various additives added as needed, in a conventional manner to form a homogeneous liquid.

[0074] To form a cured film from the curable composition of the present embodiment, for example, the curable 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 heated and cured at a temperature of 250 to 400°C. A resist pattern is formed on the cured film by performing a normal photolithography operation, and then dry etching is performed using a halogen-based plasma gas or the like, thereby forming a resist pattern by a multilayer resist method.

[0075] [Method of manufacturing resist pattern] A method for producing a resist pattern according to one embodiment of the present invention includes a coating film forming step of forming a coating film comprising the photosensitive resin composition of the present invention on a substrate, an exposure step of exposing the coating film to light, and a development step of developing the coating film after the exposure step with a dilute weak alkaline developer.

[0076] (1) Paint film formation process The coating film forming step is a step of forming a coating film on a substrate. Examples of the substrate include a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, etc. In this embodiment, a dilute weak alkaline developer is used, so even if the substrate has a transparent conductive film made of a ZnO-based film, a fine resist pattern with high heat resistance can be obtained. The coating film can be formed by applying a photosensitive resin composition (resist resin composition) onto an object such as a substrate on which photolithography is to be performed, and pre-baking at a temperature of 60 to 150° C. Examples of the coating method include spin coating, roll coating, flow coating, dip coating, spray coating, and doctor blade coating.

[0077] (2) Exposure process The exposure step is a step of exposing the coating film to light through a mask on which a pattern is drawn. Examples of light sources for exposing the coating film 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.

[0078] (3)Developing process The development process involves developing the coating film after the exposure process with a dilute, weakly alkaline developer. In the development process, a resist pattern is formed by developing the coating film after the exposure process with a dilute, weakly alkaline developer. The phenolic hydroxyl group-containing resin (A) contained in the coating film has excellent alkaline solubility, making it possible to fully develop the film even when using a dilute, weakly alkaline developer. At the same time, the phenolic hydroxyl group-containing resin (A) has excellent compatibility with the photosensitizer (B), resulting in extremely high resistance to alkaline solubility in the unexposed areas. As a result, the contrast between the exposed and unexposed areas in photolithography is high, enabling the drawing of fine patterns. Furthermore, by using a dilute, weakly alkaline developer in the development process, the resist pattern can be developed while suppressing damage to the ZnO-based film.

[0079] In this specification, the term "dilute weakly alkaline developer" refers to a 0.1 to 10% by mass aqueous solution of an inorganic salt of an acid having a pKa in the range of 6.0 to 12.0 in H2O at 23°C. Examples of inorganic acids include sodium carbonate and sodium bicarbonate. The pH of the dilute weakly alkaline developer used in the development step is preferably 8.0 or more and 12.0 or less.

[0080] When a mixed solution of an aqueous sodium carbonate solution and an aqueous sodium bicarbonate solution is used as the diluted weak alkaline developer, the blending ratio of the two is not particularly limited and can be any ratio. In particular, the mass ratio of the two [(aqueous sodium carbonate solution) / (aqueous sodium bicarbonate solution)] is preferably in the range of 80 / 20 to 20 / 80, and more preferably in the range of 80 / 20 to 60 / 40, because particularly high contrast can be obtained. [Example]

[0081] The present invention will be described in more detail below with reference to specific examples. The number average molecular weight (Mn), weight average molecular weight (Mw), and polydispersity (Mw / Mn) of the synthesized resins were measured under the following GPC measurement conditions. [GPC measurement conditions] Measuring device: Tosoh Corporation "HLC-8220 GPC" Column: Showa Denko KF802 (8.0mmΦ x 300mm) +Showa Denko KF802 (8.0mmΦ×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

[0082] Also, 13 The measurement conditions for C-NMR are as follows: [ 13 C-NMR measurement conditions] Equipment: JEOL Ltd. JNM-ECA500 Measurement mode: Decoupling with inverse gate Solvent: deuterated dimethyl sulfoxide Pulse angle: 30° pulse Sample concentration: 30% by mass Accumulation count: 4000 times Chemical shift standard: Dimethyl sulfoxide peak: 39.5 ppm

[0083] [Phenol hydroxyl group-containing resin] Example 1 A 250 mL four-neck flask equipped with a condenser was charged with 18.3 g of m-cresol, 4.9 g of glyoxylic acid, and 15.7 g of salicylaldehyde, and dissolved in 60 g of acetic acid. While cooling in an ice bath, 2 mL of sulfuric acid was added. The mixture was heated to 90°C in an oil bath, and then heated and stirred for 4 hours to allow the reaction to proceed. After the reaction, the resulting solution was reprecipitated with water to obtain a crude product. The crude product was redissolved in acetone and further reprecipitated with water. The resulting product was filtered and vacuum dried to obtain 34.1 g of an orange powder of a phenolic hydroxyl group-containing resin (novolac resin) (A-1). As a result of GPC measurement, the number average molecular weight (Mn) of resin (A-1) was 1275, the weight average molecular weight (Mw) was 4425, and the polydispersity (Mw / Mn) was 3.47. 13 It was confirmed by C-NMR that it contained a carboxyl group (172 to 178 ppm). The GPC chart is shown in Figure 1. 13The C-NMR chart is shown in Figure 2. The abundance ratio (a:b:c, molar ratio) of the structural unit (a) derived from m-cresol, the structural unit (b) derived from glyoxylic acid, and the structural unit (c) derived from salicylaldehyde was 1.00:0.34:0.76.

[0084] Example 2 The procedure of Example 1 was repeated except that the amount of glyoxylic acid was changed to 9.9 g and the amount of salicylaldehyde was changed to 10.5 g, and 32.9 g of a phenolic hydroxyl group-containing resin (A-2) powder was obtained. The Mn of the resin (A-2) was 1273, the Mw was 3299, and the Mw / Mn was 2.59. 13 C-NMR confirmed that the product contained carboxyl groups (172-178 ppm). The GPC chart is shown in Figure 3. 13 The C-NMR chart is shown in Figure 4. The abundance ratio (a:b:c, molar ratio) of the structural unit (a) derived from m-cresol, the structural unit (b) derived from glyoxylic acid, and the structural unit (c) derived from salicylaldehyde was 1.00:0.55:0.55.

[0085] Comparative synthesis example 1 A reactor equipped with a stirrer, reflux condenser, and thermometer was charged with 108 g of o-cresol, 100 g of an aqueous glyoxylic acid solution (glyoxylic acid content: 40%), 140 g of diethylene glycol dimethyl ether, and 2.2 g of p-toluenesulfonic acid, and the mixture was reacted at 100°C with stirring. Next, 108 g of o-cresol and 120 g of diethylene glycol dimethyl ether were added, and 102.2 g of an aqueous formalin solution (formaldehyde content: 37%) was added dropwise with stirring at 90°C. The mixture was refluxed for 6 hours, and then heated to 150°C to react. After the reaction was completed, the resulting solution was washed with water to remove the p-toluenesulfonic acid, and the water was distilled off under reduced pressure to obtain 216 g of a phenolic hydroxyl group-containing novolak resin powder (A-3).

[0086] Comparative synthesis example 2 The same procedure as in Example 1 was carried out except that glyoxylic acid was not used and the amount of salicylaldehyde was changed to 20.9 g, to obtain 31.2 g of a powder of a novolak resin (A-4) containing a phenolic hydroxyl group. 13 It was confirmed by C-NMR that the compound did not contain a carboxyl group (166 to 168 ppm). 13 The C-NMR chart is shown in Figure 5.

[0087] [Resist resin composition] Examples 3 and 4 Comparative Examples 1 and 2 20 g of the phenolic hydroxyl group-containing resin powder synthesized in the Examples and Comparative Synthesis Examples shown in Table 1 was dissolved in 80 g of propylene glycol monomethyl ether acetate (PGMEA) to obtain a resist resin composition.

[0088] The resist resin compositions obtained in the examples and comparative examples were evaluated for the following items. The results are shown in Table 1. (1) Heat resistance The resist 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 thin film with a thickness of 1 μm. 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 300°C and a heating rate of 10°C / min. The evaluation criteria are as follows: ○: Tg is 150℃ or higher ×: Tg is less than 150°C

[0089] (2) Alkali solubility The resist resin composition was applied to a 5-inch silicon wafer using a spin coater to a thickness of approximately 1 μm and then dried on a hot plate at 110°C for 60 seconds. The resulting wafer was immersed in developer (D-1) "1% aqueous sodium carbonate solution (pH 12)" or developer (D-2) "1% aqueous sodium bicarbonate solution (pH 8)" for 60 seconds. After immersion, the wafer was dried on a hot plate at 100°C for 60 seconds. The film thickness was measured before and after immersion in the developer, and the difference was divided by 60 to calculate the value (ADR: Å / s) to evaluate alkaline solubility. ADR1 is the ADR value for developer (D-1), and ADR2 is the ADR value for developer (D-2). The evaluation criteria are as follows: 〇: ADR is 100 or more ×: ADR is less than 100

[0090] (3) Environmental impact When synthesizing phenolic hydroxyl group-containing resins, no formaldehyde is used, and Cases where formaldehyde was used during resin synthesis were marked as x.

[0091] [Table 1]

[0092] The results in Table 1 show that the resist resin composition using the phenolic hydroxyl group-containing resin of the present invention has a high Tg and also has high solubility in a weakly alkaline developer.

[0093] [Positive-type photosensitive resin composition] Examples 5 and 6 Comparative Examples 3 and 4 20 g of powder of the phenolic hydroxyl group-containing resin synthesized in the example shown in Table 2 and 5 g of powder of 1,2-naphthoquinone diazide (P-200: manufactured by Toyo Gosei Co., Ltd.) were dissolved in 75 g of propylene glycol monomethyl ether acetate (PGMEA) to obtain a positive photosensitive resin composition.

[0094] The positive photosensitive resin compositions obtained in the examples and comparative examples were evaluated for development contrast. The development contrast was defined as the ratio (ADR1 / ADR3, ADR2 / ADR4) of the alkali-solubility ADR1 and ADR2 (Å / s) of the resist resin composition not containing a photosensitizer (Examples 3 and 4 and Comparative Examples 1 and 2) to the alkali-solubility ADR3 and ADR4 (Å / s) of the positive-type photosensitive resin composition containing a photosensitizer (Examples 5 and 6 and Comparative Examples 3 and 4). ADR3 and ADR4 were determined in the same manner as ADR1 and ADR2, respectively. Evaluations were made as follows. The results are shown in Table 2. ○: Development contrast is 10 or more ×: Development contrast is less than 10

[0095] [Table 2]

[0096] The results in Table 2 show that the positive-type photosensitive resin composition using the phenolic hydroxyl group-containing resin of the present invention has a high affinity with the photosensitizer because the addition of the photosensitizer has a large dissolution suppression effect, and therefore the sensitivity is also high.

Claims

1. A structural unit (a) derived from a phenol compound; a structural unit (b) derived from an aliphatic aldehyde compound having a carboxyl group; and and a structural unit (c) derived from an aromatic aldehyde compound, The phenolic hydroxyl group-containing resin, wherein the aromatic aldehyde compound is a compound represented by the following formula (3): 【Chemistry 5】 (In formula (3), R 3 is a group selected from the group consisting of an aliphatic hydrocarbon group, an alkoxy group, a halogen atom, a cyano group, and a nitro group, n is an integer of 0 to 3, and p is an integer of 0 to 2.)

2. 2. The phenolic hydroxyl group-containing resin according to claim 1, wherein the phenol compound is a compound represented by the following formula (1): 【Chemistry 6】 (In formula (1), R １ is an aliphatic hydrocarbon group, an alkoxy group, an aryl group, an aralkyl group, or a halogen atom; l is an integer of 0 to 2, and m is 1 or 2.

3. 3. The phenolic hydroxyl group-containing resin according to claim 1, wherein the aliphatic aldehyde compound having a carboxyl group is a compound represented by the following formula (2): 【Chemistry 7】 (In formula (2), R is a single bond or a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.)

4. 3. The phenolic hydroxyl group-containing resin according to claim 1, wherein the molar ratio of the structural unit (a), the structural unit (b), and the structural unit (c) (structural unit (a):structural unit (b):structural unit (c)) is 1.0:0.05 to 1.0:0.1 to 1.

5.

5. A photosensitive resin composition comprising the phenolic hydroxyl group-containing resin according to claim 1 or 2 and a quinone diazide photosensitizer.

6. 6. The photosensitive resin composition according to claim 5, further comprising a phenolic resin having a calix structure including a structural unit (a) derived from a phenolic compound and a structural unit (b) derived from an aliphatic aldehyde compound having a carboxyl group.

7. The photosensitive resin composition according to claim 5 , wherein the quinone diazide photosensitizer comprises a naphthoquinone diazide compound.

8. A resist film obtained from the photosensitive resin composition according to claim 5.

9. A curable composition comprising the phenolic hydroxyl group-containing resin according to claim 1 or 2 and a curing agent.

10. A cured product of the curable composition according to claim 9.

11. a coating film forming step of forming a coating film comprising the photosensitive resin composition according to claim 5 on a substrate; an exposure step of exposing the coating film to light; a developing step of developing the coating film after the exposure step with a 0.1 to 10 mass % aqueous solution of one or more compounds selected from sodium carbonate and sodium bicarbonate.

12. The method for producing a resist pattern according to claim 11, wherein the pH of the aqueous solution is 8.0 or more and 12.0 or less.

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