KR101424521B1 - Positive resist composition - Google Patents

Abstract

(A) derived from a tertiary butyl acrylate or tertiary butyl methacrylate and a polymerization unit (b) derived from a compound of the general formula (1), wherein the content of the polymerized units (a) (B) and 10 to 70 mol% of the polymer (A), 30 to 90 mol% of the polymer (B) and 50 to 300,000 in terms of polystyrene C). ≪ / RTI >

Formula 1

In the above formula (1)

R ¹ is a hydrogen atom or a methyl group,

R ² is an alkyl group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 5 to 10 carbon atoms, or a group represented by formula (2).

(2)

In the above formula (2)

R ³ is an alkylene group having 1 to 6 carbon atoms,

R ⁴ is an alkyl group having 1 to 6 carbon atoms,

n is an integer of 1 to 30;

A positive resist composition, a polymerization unit, a polymer, an acid generator, and a basic compound.

Description

[0001] The present invention relates to a positive resist composition,

The present invention relates to a positive resist composition.

The positive resist composition is used for the formation of bumps in the production of semiconductor devices, the formation of wiring patterns or thick film photoresist laminations in the production of circuit boards, and the formation of thick resist patterns in the production of semiconductor devices .

As a positive resist composition for a thick film, US Patent Publication No. 2004/038148 discloses a composition comprising a copolymer of p-hydroxystyrene, styrene and 2-benzyl-2-propyl acrylate and an acid generator, Open Patent Publication No. 2004-309775 discloses a composition comprising a copolymer of 1-ethylcyclohexyl methacrylate and 2-ethoxyethyl acrylate, a novolac resin and an acid generator.

It is an object of the present invention to provide a positive resist composition in which a pattern having good resolution and shape is obtained.

The present invention provides the following.

(1) A polymer composition comprising (a) a polymerization unit derived from tertiary butyl acrylate or tert-butyl (meth) acrylate and (b) a polymerization unit derived from a compound represented by the formula (1) (B) and 10 to 70 mol% of the polymer (A), 30 to 90 mol% of the polymer (B) and 50 to 300,000 in terms of polystyrene C). ≪ / RTI >

In the above formula (1)

R ¹ is a hydrogen atom or a methyl group,

R ² is an alkyl group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 5 to 10 carbon atoms, or a group represented by formula (2).

In the above formula (2)

R ³ is an alkylene group having 1 to 6 carbon atoms,

R ⁴ is an alkyl group having 1 to 6 carbon atoms,

n is an integer of 1 to 30;

<2> The positive resist composition according to <1>, wherein R ² is an alkyl group having 1 to 6 carbon atoms or a cyclic hydrocarbon group having 5 to 10 carbon atoms.

<3> R ^2, the positive resist composition according to a group of the formula (2) wherein the items <1>.

<4> The positive resist composition according to any one of <1> to <3>, wherein the alkali-soluble polymer is a novolac polymer.

<5> The positive resist composition according to any one of <1> to <3>, wherein the alkali-soluble polymer is a polymer containing a polymerization unit derived from hydroxystyrene.

<6> The positive resist composition according to any one of <1> to <5>, wherein the acid generator is a salt of the formula 3 or a compound of the formula 4.

In the above formulas (3) and (4)

A is an oxygen atom or a sulfur atom,

R ⁵ and R ⁶ are the same or different and are each independently a methyl group or a phenyl group,

R ⁷ and R ⁸ are each a perfluoroalkyl group having 1 to 8 carbon atoms.

<7> The positive resist composition according to any one of <1> to <6>, further comprising a basic compound.

(8) A polymer composition comprising a polymerization unit (a) derived from tertiary butyl acrylate or tertiary butyl methacrylate and a polymerization unit (b) derived from a compound represented by formula (1) , The content of the polymeric unit (b) is 30 to 90 mol%, and the weight average molecular weight in terms of polystyrene is 50,000 to 300,000.

Formula 1

In the above formula (1)

R ¹ is a hydrogen atom or a methyl group,

R ² is an alkyl group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 5 to 10 carbon atoms, or a group represented by formula (2).

(2)

In the above formula (2)

R ³ is an alkylene group having 1 to 6 carbon atoms,

R ⁴ is an alkyl group having 1 to 6 carbon atoms,

n is an integer of 1 to 30;

The use of the positive resist composition of the present invention enables a pattern having good resolution and shape to be obtained. Therefore, the positive resist composition of the present invention can be suitably used for forming a bump in the production of a semiconductor device, Formation of a thick film resist layered product, formation of a thick resist film in the production of a semiconductor device, and the like.

The polymer (A) of the positive resist composition of the present invention can be obtained by copolymerizing a polymerized unit (a) derived from tertiary butyl acrylate or tertiary butyl methacrylate and at least one polymerized unit (b) derived from the compound of formula (A) in an amount of 10 to 70 mol%, a content of a polymeric unit (b) of 30 to 90 mol%, and a weight average molecular weight in terms of polystyrene of 50,000 to 300,000 based on the total polymerized units.

Formula 1

In the above formula (1)

R ¹ is a hydrogen atom or a methyl group,

R ² is an alkyl group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 5 to 10 carbon atoms, or a group represented by formula (2).

(2)

In the above formula (2)

R ³ is an alkylene group having 1 to 6 carbon atoms,

R ⁴ is an alkyl group having 1 to 6 carbon atoms,

n is an integer of 1 to 30;

The polymerization unit (a) is a polymerization unit derived from a tertiary butyl acrylate or tertiary butyl methacrylate, and specifically a polymerization unit represented by the following formula.

The content of such a polymerized unit (a) is 10 to 70 mol% with respect to the total polymerized units of the polymer (A).

Polymeric unit (b) is at least one polymeric unit derived from the compound of formula (1). As the polymer (A), the polymer unit (b) preferably contains 1 to 3 polymerization units derived from the compound of the formula (1), more preferably 1 to 2.

Examples of the alkyl group having 1 to 6 carbon atoms in the general formula (1) include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, , and n-hexyl group. Examples of the cyclic hydrocarbon group having 5 to 10 carbon atoms include a cyclopentyl group, a cyclohexyl group, and an adamantyl group.

Examples of the alkylene group having 1 to 6 carbon atoms in the general formula (2) include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group and a hexamethylene group, and a methylene group and an ethylene group are preferable. Examples of the alkyl group having 1 to 6 carbon atoms include the same ones as described above.

Specific examples of the compound of formula (1) include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, cyclopentyl acrylate, cyclopentyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, adamantyl acrylate, Ethylene glycol monomethyl ether acrylate, ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether acrylate, ethylene glycol monoethyl ether methacrylate, ethylene glycol monopropyl ether acrylate, ethylene glycol mono Ethylene glycol monobutyl ether acrylate, ethylene glycol monobutyl ether methacrylate, diethylene glycol monomethyl ether acrylate, diethylene glycol monomethyl ether methacrylate, triethylene glycol monomethyl ether acrylate Triethylene glycol monomethyl ether methacrylate, tetraethylene glycol monomethyl ether acrylate, tetraethylene glycol monomethyl ether methacrylate, pentaethylene glycol monomethyl ether acrylate, pentaethylene glycol monomethyl ether methacrylate, Hexaethylene glycol monomethyl ether acrylate, hexaethylene glycol monomethyl ether acrylate, hexaethyleneglycol monomethyl ether methacrylate, octaethyleneglycol monomethyl ether acrylate, octaethyleneglycol monomethyl ether methacrylate, nonaethylene glycol monomethyl ether acrylate, nonaethylene glycol And monomethyl ether methacrylate.

As the compound of the formula (1), commercially available ones are used.

When the polymerization unit (a) is a polymerization unit derived from tertiary butyl acrylate, R ¹ is preferably a hydrogen atom, and when the polymerization unit (a) is a polymerization unit derived from tertiary butyl methacrylate, R ¹ is preferably a methyl group.

As the polymerization unit (b), a polymerization unit in which R ² is a group represented by the formula (2) is preferable, and a polymerization unit in which R ² is a group represented by the formula (2) and n is 2 to 16 is more preferable.

The weight average molecular weight of the polymer (A) in terms of polystyrene is 50,000 to 300,000, preferably 100,000 to 250,000, and preferably 100,000 to 200,000.

The content of such a polymerized unit (b) is 30 to 90 mol% with respect to the total polymerized units of the polymer (A).

Polymer (A) can be produced by polymerizing a corresponding monomer (tertiary butyl acrylate or tertiary butyl methacrylate and at least one compound of formula (I)) in the presence of a polymerization initiator.

Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile) , 2'-azobis (2,4-dimethylvaleronitrile), and the like. The amount thereof is usually from 1 to 20 mol% based on the total monomers, and the weight average molecular weight of the obtained polymer (A) in terms of polystyrene can be adjusted by adjusting the amount of the polymerization initiator used.

The content of the polymerized units (a) and (b) in the obtained polymer (A) can be adjusted by adjusting the amount of the monomer used.

The polymerization temperature is usually 0 to 150 ° C.

The polymerization reaction is usually carried out in the presence of a solvent, and it is preferable that the solvent is a solvent which dissolves the monomers to be used, the polymerization initiator and the polymer to be obtained. Specific examples of the solvent include hydrocarbon solvents such as toluene, ether solvents such as 1,4-dioxane and tetrahydrofuran, ketone solvents such as methyl isobutyl ketone, alcohol solvents such as isopropyl alcohol, and cyclic solvents such as gamma -butyrolactone Glycol ether ester solvents such as ester solvents and propylene glycol monomethyl ether acetate, and the like. The amount thereof to be used is not particularly limited.

After completion of the reaction, the polymer (A) is precipitated, for example, by mixing the obtained reaction mixture with a solvent which does not dissolve or hardly dissolve the polymer (A), and the precipitated polymer (A) And can be taken out by separation by means.

The polymer (B) of the positive resist composition of the present invention is soluble in alkali.

As specific examples of the polymer (B), polymers containing polymerized units derived from novolac polymers and hydroxystyrene can be mentioned, and novolak polymers are preferred.

The novolak polymer can be produced, for example, by reacting a phenol compound and an aldehyde compound in the presence of an acid catalyst.

Examples of the phenol compound include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 3,4- 2,3,5-trimethylphenol, 2,3-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2,3-butylphenylmethylphenol, Phenol, 2-methyl resorcinol, 4-methyl resorcinol, 5-methyl resorcinol, 2-methoxyphenol, 3-methoxyphenol, 4-methoxyphenol, 2,3-dimethoxyphenol, 2 3-ethylphenol, 4-ethylphenol, 2,5-dimethoxyphenol, 2-methoxyphenol, 4- Diethylphenol, 3,5-diethylphenol, 2,3,5-triethylphenol, 2-naphthol, 1,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, And polyhydroxytriphenylmethane obtained by a polymerization reaction of xylanol and hydroxybenzaldehyde. These phenol compounds may be used alone or in combination of two or more. Among these, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5- , 5-trimethylphenol, 2,3-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2,3-butylphenylmethylphenol and 2,3- Do.

Examples of the aldehyde compound include aldehyde compounds such as formaldehyde, acetaldehyde, propionaldehyde, n-butylaldehyde, isobutylaldehyde, acrolein, crotonaldehyde, cyclohexanaldehyde, cyclopentanaldehyde, furfural, furacrylate, benzaldehyde, there may be mentioned m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, 2,4-dimethylbenzaldehyde, 2,5-dimethylbenzaldehyde, 3,4-dimethylbenzaldehyde, 3,5-dimethylbenzaldehyde, o-hydroxybenzaldehyde, m -Hydroxybenzaldehyde, p-hydroxybenzaldehyde, phenylacetaldehyde, cinnamaldehyde and the like. These aldehyde compounds may be used alone or in combination of two or more. Of these aldehyde compounds, formaldehyde is preferable in view of industrial availability.

Usually, an excessive amount of phenol compound is used for the aldehyde compound.

Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, perchloric acid and phosphoric acid, organic acids such as formic acid, acetic acid, oxalic acid, trichloroacetic acid and p-toluenesulfonic acid, and divalent metal salts such as zinc acetate, zinc chloride and magnesium acetate. . These acid catalysts may be used alone or in combination of two or more. The amount of such an acid catalyst to be used is usually 0.01 to 1 mol times, based on 1 mol of the aldehyde compound.

The reaction of the phenol compound and the aldehyde compound can be carried out according to a known method for producing a novolac polymer. The reaction temperature is usually 60 to 120 ° C, and the reaction time is usually about 2 to 30 hours. The reaction is usually carried out in a solvent inert to the reaction.

After completion of the reaction, the novolak polymer can be taken out, for example, by adding an insoluble organic solvent to the reaction mixture, if necessary, and washing the reaction mixture with water and concentrating.

Examples of the polymer containing polymerized units derived from hydroxystyrene include poly (o-hydroxystyrene), poly (m-hydroxystyrene), poly (p-hydroxystyrene) , A polymer containing a polymerization unit represented by the general formula (12) and a general formula (13), and the like.

In the above formulas (11) to (13)

R ¹⁰ is an alkyl group having 1 to 4 carbon atoms,

R ¹¹ is an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 5 to 7 carbon atoms,

R ¹⁰ and R ¹¹ may combine to form a trimethylene group or a tetramethylene group.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ¹⁰ include a linear or branched alkyl group having 1 to 4 carbon atoms such as a methyl group, ethyl group, n-propyl group, isopropyl group and n-butyl group, . Examples of the alkyl group having 1 to 6 carbon atoms represented by R ¹¹ include linear or branched alkyl groups having 1 to 6 carbon atoms such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, n- Examples of the cycloalkyl group having 5 to 7 carbon atoms include a cyclopentyl group, a cyclohexyl group and a cycloheptyl group, preferably an ethyl group, an n-propyl group and a cyclohexyl group, and a cyclohexyl group is more preferable Do.

The polymer containing the polymerization units of the above formulas (2) and (3) has an acetal structure.

In the polymer containing the polymeric units of the above formulas (2) and (3), the proportion of the polymeric units of the general formula (3) is usually 10 to 90 mol% based on the total polymerized units.

Polymers containing polymerized units derived from hydroxystyrene can be prepared by polymerizing the corresponding monomers in the presence of an acid catalyst.

Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, perchloric acid and phosphoric acid, and organic acids such as formic acid, acetic acid, oxalic acid, trichloroacetic acid and p-toluenesulfonic acid. The amount of such an acid catalyst to be used is usually 0.0001 to 1% by weight based on the sum of hydroxystyrene and styrene.

Such a polymerization reaction is usually carried out in the presence of a solvent, and the solvent is not particularly limited as long as it is a solvent inert to the reaction. The reaction temperature is usually 0 to 100 占 폚, and the reaction time is usually about 0.5 to 48 hours.

After completion of the reaction, for example, an organic solvent insoluble in water is added to the reaction mixture, if necessary, and a basic substance such as triethylamine is added to the reaction mixture if necessary, followed by washing with water and concentration, Polymers containing polymerized units derived from styrene may be withdrawn.

The acid generator (C) of the positive resist composition of the present invention is not particularly limited as long as it is a compound which decomposes upon irradiation with light or radiation to generate an acid. The acid generated from the acid generator acts on the polymer in the positive resist composition and the cleavage reaction of the unstable group in the acid existing in the polymer progresses so that the polymer becomes soluble in the aqueous alkali solution.

As the acid generator, there may be mentioned at least one compound selected from the group consisting of an onium salt, a halogen-containing compound, a diazoketone compound, a sulfon compound and a sulfonic acid compound, and onium salt or sulfonic acid compound is preferable.

Specific examples of onium salts include salts of the formula (5a), salts of the formula (5b), salts of the formula (5c), salts of the formula (3) and salts of the formula (4).

(3)

Formula 4

In the above formulas (5a), (5b), (5c), (3) and (4)

P ¹ , P ² and P ³ independently represent a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms,

a, b and c are, independently, an integer from 0 to 3, if A is a case of 2 or 3, a plurality of P ¹ is, may be the same or different, b is 2 or 3, a plurality of P ² And when c is 2 or 3, the plurality of P &lt; ³ &gt; may be the same as or different from each other,

Z ^- is an organic counterion,

P ⁴ and P ⁵ independently represent a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms,

d and e are, independently, 0 or 1,

P ⁶ and P ⁷ are independently an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 10 carbon atoms or a combination of P ⁶ and P ⁷ to form a divalent aliphatic hydrocarbon group having 3 to 7 carbon atoms, one or more of -CH ₂ - may be substituted with a carbonyl group, an oxygen atom or a sulfur atom), and form a ring together with the adjacent S ⁺ a,

P ⁸ is a hydrogen atom,

P ⁹ is an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aromatic ring group which may be substituted,

P ⁸ and P ⁹ combine to form a divalent aliphatic hydrocarbon group or form a ring together with adjacent -CHCO-,

A is an oxygen atom or a sulfur atom,

R ⁵ and R ⁶ are, independently, a methyl group or a phenyl group,

R ⁷ and R ⁸ are each a perfluoroalkyl group having 1 to 8 carbon atoms.

In the ^{P 1, P 2, P 3} , P 4 and P ^5, Specific examples of the alkyl group having 1 to 6 carbon atoms, methyl group, ethyl group, n- propyl group, isopropyl group, n- butyl group, a tert-butyl group, pentyl group, n-hexyl group and the like. Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, n-propoxy group, isopropoxy group and n-butoxy group .

Specific examples of the alkyl group having 1 to 6 carbon atoms in P ⁶ , P ⁷ and P ⁹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, And hexyl group. Examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

Examples of the divalent aliphatic hydrocarbon group having 3 to 7 carbon atoms formed by combining P ⁶ and P ⁷ include a trimethylene group, a tetramethylene group, and a pentamethylene group. P ⁶ and P ⁷ are bonded to each other to form an adjacent Specific examples of the ring formed by S ^{&lt; +} &gt; include pentamethylene sulfonyl group, tetramethylene sulfonyl group, oxybisethylene sulfonyl group and the like.

In P ⁹ , examples of the aromatic ring group which may be substituted with carbon include a phenyl group, a tolyl group, a xylyl group and a naphthyl group. Examples of the divalent aliphatic hydrocarbon group formed by combining P ⁸ and P ⁹ include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group and a pentamethylene group. P ⁸ and P ⁹ are bonded to each other to form a Examples of the ring formed together with -CHCO- include a 2-oxocyclohexyl group and a 2-oxocyclopentyl group.

Examples of the perfluoroalkyl group having 1 to 8 carbon atoms in the general formulas (3) and (4) include a perfluoromethyl group, a perfluoroethyl group, a perfluoro-n-propyl group, a perfluoroisopropyl group, butyl group, a perfluoro-n-pentyl group, a perfluoro-n-hexyl group, a perfluoro-n-pentyl group, N-heptyl group, perfluoro-n-octyl group and the like, and a perfluoroalkyl group having 1 to 4 carbon atoms is preferable.

Specific examples of the cations in the salts of the formulas (5a), (5b) and (5c) include the following cations.

Specific examples of the cation in the salt of the formula (3) include the following cations.

Examples of the organic counter ion Z &lt; ^- &gt; include an anion of the formula (6).

In the above formula (6)

Q ¹ , Q ² , Q ³ , Q ⁴ and Q ⁵ are each independently a hydrogen atom, a halogen atom, an aldehyde group, a straight or branched alkyl group having 1 to 16 carbon atoms, a straight or branched alkoxy group having 1 to 16 carbon atoms, A halogenated alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, a cyano group, an alkylthio group having 1 to 4 carbon atoms, an alkylsulfonyl group having 1 to 4 carbon atoms, Or a group of formula (7).

In the above formula (7)

X is a straight chain alkylene group which may contain an oxygen atom or a sulfur atom,

Cy ¹ is an alicyclic hydrocarbon group having 3 to 20 carbon atoms.

Examples of the straight or branched chain alkyl group having 1 to 16 carbon atoms represented by the formula (6) include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, a tertiary butyl group, Octyl group, n-decyl group, n-dodecyl group, and n-hexadecyl group.

Examples of the straight or branched chain alkoxy group having 1 to 16 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, a n-butoxy group, a tert- An isopentyloxy group, an n-decyloxy group, an n-dodecyloxy group, and an n-hexadecyloxy group.

Examples of the halogenated alkyl group having 1 to 8 carbon atoms include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, and a perfluorobutyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a methoxyphenyl group, and a naphthyl group. Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, a chlorobenzyl group, and a methoxybenzyl group. Examples of the alkylthio group having 1 to 4 carbon atoms include a methylthio group, an ethylthio group, a propylthio group, an isopropylthio group, and a butylthio group. Examples of the alkylsulfonyl group having 1 to 4 carbon atoms include a methylsulfonyl group, an ethylsulfonyl group, an n-propylsulfonyl group, an isopropylsulfonyl group and an n-butylsulfonyl group.

When at least ^two of Q ¹ , Q ² , Q ³ , Q ⁴ and Q ⁵ in the general formula (6) are a group of the general formula (7), X and Cy ¹ of the corresponding group may be independently selected.

X is a group shown below, and a straight chain alkylene group having 1 to 7 carbon atoms represented by the following (a-1) to (a-15) is preferable.

As Cy ¹ , the following groups may be mentioned, and examples thereof include a cyclohexyl group (b-4), a 2-norbornyl group (b-21), a 2- adamantyl group -24).

As the organic counter ion Z &lt; ^{- &} gt ;, an anion represented by the following formula may also be used.

The organic counter ion Z &lt; ^- &gt; may also be an anion of the following general formula (8a).

In the above formula (8a)

Q ⁶ is a perfluoroalkyl group having 1 to 20 carbon atoms, a naphthyl group which may be substituted or an anthryl group which may be substituted.

Specific examples of the anion of formula (8a) include the following.

As an organic counter ion Z &lt; ^{- &} gt ;, an anion of the following formula (8b) may also be mentioned.

In the above formula (8b)

Q ⁷ and Q ⁸ are independently a perfluoroalkyl group having 1 to 20 carbon atoms or an aromatic ring group having 6 to 20 carbon atoms which may be substituted.

Specific examples of the anion of formula (8b) include the following.

Examples of the salt of the formula (4) include N-trifluoromethylsulfonyloxy-1,8-naphthalimide, N-nonafluorobutylsulfonyloxy-1,8-naphthalimide and the like.

Among these acid generators, the salt of the formula (3) or the compound of the formula (4) is preferred, and the compound of the formula (4) is more preferable.

The weight ratio of the polymer (A) to the polymer (B) (polymer (A) / polymer (B)) in the positive resist composition of the present invention is usually 7/3 to 5/5.

The positive resist composition of the present invention usually contains 95 to 99% by weight of a polymer component and 1 to 5% by weight of an acid generator (C) based on the total solid content of the positive resist composition. In the present invention, the total solids content means the whole amount excluding the solvent.

The positive resist composition of the present invention may contain other polymer besides the polymer (A), the polymer (B) and the acid generator (C).

The other polymer is preferably a polymer which has an acid-labile group and is itself insoluble or sparingly soluble in an aqueous alkali solution but is soluble in an aqueous alkaline solution by the action of an acid.

Acid-unstable group &quot; of the polymer that is insoluble or sparingly soluble in an aqueous alkali solution but becomes soluble in an aqueous alkali solution by the action of an acid is not limited to an alkyl group having a carbon atom adjacent to the oxygen atom An ester group, an ester of a carboxylic acid such as an alicyclic ester group in which a carbon atom adjacent to an oxygen atom is a quaternary carbon atom, and a lactone ester group in which a carbon atom adjacent to an oxygen atom is a quaternary carbon atom. In the present specification, the "ester group" means a structure having an ester of a carboxylic acid. Specifically, the "tertiary butyl ester group" means "a structure having a tertiary butyl ester of a carboxylic acid" and may be described as "-COOC (CH ₃ ) ₃ ". In addition, the "quaternary carbon atom" means a "carbon atom bonded to four substituents other than a hydrogen atom".

Examples of the acid-unstable group include alkyl ester groups: methoxymethyl ester group, ethoxymethyl ester group, 1-ethoxyethyl ester group, 1- Ethoxypropyl ester group, a 1- (2-methoxyethoxy) ethyl ester group, a 1- (2-acetoxyethoxy) ethyl ester group , 1- [2- (1-adamantyloxy) ethoxy] ethyl ester group, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl ester group, tetrahydro- , Acetal-type ester groups such as tetrahydro-2-pyranyl ester group; A carbon atom adjacent to an oxygen atom such as an isobornyl ester group, a 1-alkylcycloalkyl ester group, a 2-alkyl-2-adamantyl ester group and a 1- (1-adamantyl) And alicyclic ester groups which are self-quaternary carbon atoms.

Examples of polymers which are unstable in acid and which are insoluble or hardly soluble in an aqueous alkali solution but which are soluble in an aqueous alkali solution by the action of an acid include polymers having structural units derived from esters of acrylic acid having an acid labile group, Polymers having structural units derived from esters of methacrylic acid having an unstable group are preferred.

Specific examples of the polymer which is unstable in acid and which itself is insoluble or hardly soluble in an aqueous alkali solution but which is soluble in an alkali aqueous solution by the action of an acid include methoxymethyl acrylate, methoxymethyl methacrylate, ethoxymethyl acrylate Methoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-isobutoxyethyl acrylate, 1-isobutoxyethyl methacrylate, 1- Methacryloxypropyl methacrylate, 1-ethoxypropyl methacrylate, 1-ethoxypropyl methacrylate, 1- (2-methoxyethoxy) ethyl acrylate, 1- Ethyl methacrylate, 1- [2- (1-adamantyloxy) ethyl methacrylate, 1- (2-acetoxyethoxy) Ethoxy] ethyl acrylate, 1- [2- (1-adamantyloxy) Ethyl methacrylate, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl acrylate, 1- [2- (1-adamantanecarbonyloxy) ethoxy] ethyl methacrylate Tetrahydro-2-furyl methacrylate, tetrahydro-2-pyranyl acrylate, tetrahydro-2-pyranyl methacrylate, isobornyl acrylate, isoboron Alkyl-2-adamantyl acrylate, 2-alkyl-2-adamantyl methacrylate, 1- ( 1-adamantyl) -1-alkyl alkyl acrylate, and 1- (1-adamantyl) -1-alkyl alkyl methacrylate.

Among them, polymerization units derived from 3-hydroxy-1-adamantyl acrylate, polymerization units derived from methacrylic acid 3-hydroxy-1-adamantyl, acrylic acid 3,5-dihydroxy- A polymer comprising a polymerization unit derived from adamantyl, a polymerization unit derived from 3,5-dihydroxy-1-adamantyl methacrylate, a polymerization unit represented by the following formula (a) or a polymerization unit represented by the following formula desirable.

Wherein R ²¹ and R ²² are independently a hydrogen atom or a methyl group; R ²³ and R ²⁴ are, independently, a methyl group, a trifluoromethyl group or a halogen atom; p and q are integers of 0 to 3, and when p is 2 or 3, R ³ may be different from each other, and when q is 2 or 3, R ²⁴ may be different from each other]

Acrylate, 3-hydroxy-1-adamantyl acrylate, 3-hydroxy-1-adamantyl methacrylate and the like can be used. Commercially available monomers such as acrylic acid, methacrylic With an acid or a halide thereof, may be used.

Examples of the monomer giving the polymeric units of the formulas (a) and (b) include acrylic acid esters or methacrylic acid esters of alicyclic lactones having a hydroxyl group shown below, and mixtures thereof. Such esters can be produced by reacting an alicyclic lactone having a corresponding hydroxyl group with acrylic acid, methacrylic acid, etc. (Japanese Patent Application Laid-Open No. 2000-26446).

Examples of other polymers include acryloyloxy- gamma -butyrolactone, methacryloyloxy- gamma -butyrolactone, and specific examples thereof include alpha -acryloyloxy- gamma -butyrolactone, alpha -Methacryloyloxy- gamma -butyrolactone,? -Acryloyloxy-?,? -Dimethyl-? -Butyrolactone,? -Methacryloyloxy- ?,? -Dimethyl-? -Butyro Lactone,? -Acryloyloxy-? -Methyl-? -Butyrolactone,? -Methacryloyloxy-? -Methyl-? -Butyrolactone,? -Acryloyloxy-? -Butyrolactone, ? -methacryloyloxy-? -butyrolactone,? -methacryloyloxy-? -methyl-? -butyrolactone, and the like.

The content of such another polymer is preferably 0 to 50% by weight based on the total amount of the polymer (A), the polymer (B) and the other polymer.

In the positive resist composition of the present invention, deterioration in performance due to deactivation of an acid with the passage of time after exposure can be improved by adding an organic basic compound, particularly a nitrogen-containing basic organic compound, as a quencher. Specific examples of such nitrogen-containing basic organic compounds include amine compounds

T ¹ and T ² are independently a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, and the alkyl group, the cycloalkyl group and the aryl group may be substituted with a hydroxyl group, an alkyl group having 1 to 4 carbon atoms An amino group, and an alkoxy group having 1 to 6 carbon atoms which may be substituted with an alkoxy group having 1 to 6 carbon atoms; T ³ and T ⁴ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an alkoxy group, and the alkyl group, the cycloalkyl group, the aryl group and the alkoxy group may be substituted with a hydroxyl group or an alkyl group having 1 to 4 carbon atoms An amino group which may be substituted, and an alkoxy group having 1 to 6 carbon atoms, and T ³ and T ⁴ may combine to form an aromatic ring together with the bonding carbon atoms thereof; T ⁵ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group or a nitro group, and the alkyl group, the cycloalkyl group, the aryl group and the alkoxy group may be substituted with a hydroxyl group or an alkyl group having 1 to 4 carbon atoms An amino group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms; T ⁶ is an alkyl group or a cycloalkyl group, and the alkyl group and the cycloalkyl group may be substituted with a hydroxyl group, an amino group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and an amino group with 1 to 6 carbon atoms which may be substituted with an alkoxy group having 1 to 6 carbon atoms Lt; / RTI &gt; alkoxy group; A ¹ is -CO-, -NH-, -S-, -SS-, an alkylene group or an alkenylene group, and the alkylene group and at least one methylene group of the alkenylene group may be substituted with -O-]

의 수산화 4급 암모늄[여기서, T¹, T² 및 T⁶은 위에서 정의한 바와 같고; T⁷은 수소원자, 알킬기, 사이클로알킬기 또는 아릴기이고, 당해 알킬기, 당해 사이클로알킬기는, 하이드록실기, 탄소수 1 내지 4의 알킬기로 치환될 수 있는 아미노기 및 탄소수 1 내지 6의 알콕시기로 이루어진 그룹으로부터 선택된 하나 이상의 기로 치환될 수 있으며, 당해 아릴기는 하이드록실기, 탄소수 1 내지 4의 알킬기로 치환될 수 있는 아미노기, 탄소수 1 내지 6의 알콕시기 및 탄소수 1 내지 4의 퍼플루오로알킬기로 이루어진 그룹으로부터 선택된 하나 이상의 기로 치환될 수 있다]을 들 수 있다. And formula

Quaternary ammonium hydroxide, wherein T ¹ , T ² and T ⁶ are as defined above; T ⁷ represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, and the alkyl group, the cycloalkyl group may be substituted with a group selected from the group consisting of a hydroxyl group, an amino group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms The aryl group may be substituted with one or more selected from the group consisting of a hydroxyl group, an amino group which may be substituted with an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms and a perfluoroalkyl group having from 1 to 4 carbon atoms Which may be substituted with one or more selected groups.

The alkyl group in T ¹ , T ² , T ³ , T ⁴ , T ⁵ , T ⁶ and T ⁷ preferably has about 1 to 10 carbon atoms and more preferably about 1 to 6 carbon atoms.

Examples of the amino group which may be substituted with an alkyl group having 1 to 4 carbon atoms include an amino group, a methylamino group, an ethylamino group, an n-butylamino group, a dimethylamino group and a diethylamino group.

Examples of the alkoxy group having 1 to 6 carbon atoms which may be substituted with an alkoxy group having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, N-hexyloxy group, 2-methoxyethoxy group and the like.

An alkyl group which may be substituted with at least one group selected from the group consisting of a hydroxyl group, an amino group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms which may be substituted with an alkoxy group having 1 to 6 carbon atoms Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tertiary butyl group, an n-pentyl group, , A 2- (2-methoxyethoxy) ethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 2-aminoethyl group, a 4-aminobutyl group and a 6-aminohexyl group.

The cycloalkyl group in T ¹ , T ² , T ³ , T ⁴ , T ⁵ , T ⁶ and T ⁷ preferably has about 5 to 10 carbon atoms. A cycloalkyl group which may be substituted with at least one group selected from the group consisting of a hydroxyl group, an amino group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms which may be substituted with an alkoxy group having 1 to 6 carbon atoms , Specific examples thereof include a cyclopentyl group, a cyclohexyl group, a cyclopentyl group, and a cyclooctyl group.

The aryl group in T ¹ , T ² , T ³ , T ⁴ and T ⁵ preferably has about 6 to 10 carbon atoms. An aryl group which may be substituted with at least one group selected from the group consisting of a hydroxyl group, an amino group which may be substituted with an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms which may be substituted with an alkoxy group having 1 to 6 carbon atoms Is a phenyl group, a naphthyl group, or the like.

T ⁷ aryl group is preferably about 6 to 10 carbon atoms in the. Specific examples of the aryl group which may be substituted with at least one group selected from the group consisting of a hydroxyl group, an amino group which may be substituted with an alkyl group having from 1 to 4 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms and a perfluoroalkyl group having from 1 to 4 carbon atoms Examples include a phenyl group, a naphthyl group, and a 3-trifluoromethylphenyl group.

The alkoxy group in T ³ , T ⁴ and T ⁵ is preferably about 1 to 6 carbon atoms, and specific examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, Tert-butoxy group, n-pentyloxy group, n-hexyloxy group and the like.

The alkylene group and alkenylene group in A ¹ preferably have 2 to 6 carbon atoms. Specific examples of the alkylene group include an ethylene group, a trimethylene group, a tetramethylene group, a methylenedioxy group, an ethylene-1,2-dioxy group and the like. Specific examples of the alkenylene group include an ethene-1,2-diyl group, Propene-1,3-diyl group, 2-butene-1,4-diyl group and the like.

Specific examples of such amine compounds include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 1-naphthylamine , 2-naphthylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenyl Methane, 4,4'-diamino-3,3'-diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, -Methylaniline, piperidine, diphenylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine , Methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonyl There may be mentioned, for example, aliphatic amines such as dimethylamine, diethylamine, diethylamine, diethylamine, diethylamine, diethylamine, diethylamine, diethylamine, diethylamine, diethylamine, diethylamine, (2-methoxyethoxy) ethylamine, triisopropanolamine, N, N-dimethylaniline, 2,6-isopropylaniline, imidazole, pyridine, 4-methylpyridine, Di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,3 Di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2- 4,4'-dipyridyl disulfide, 4,4'-dipyridyl disulfide, 1,2-bis (4-pyridyl) ethylene, 2,2'- Picolylamine and the like.

Specific examples of such quaternary ammonium hydroxide include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra-n-hexylammonium hydroxide, tetra-n-octylammonium hydroxide, phenyltrimethylammonium hydroxide, Trifluoromethyl) phenyltrimethylammonium hydroxide, (2-hydroxyethyl) trimethylammonium hydroxide (so-called choline), and the like.

Also, a hindered amine compound having a piperidine skeleton as disclosed in Japanese Patent Application Laid-Open No. 11-52575 may be used as a quencher.

The positive resist composition of the present invention preferably contains a quencher in an amount of 0.001 to 1% by weight based on the total solids content.

The positive resist composition of the present invention may contain a small amount of various additives such as a sensitizer, a dissolution inhibiting agent, a surfactant, a stabilizer, and a dye, as needed, so long as the effect of the present invention is not impaired.

The positive resist composition of the present invention is usually used in the form of a resist solution composition in which each of the above components is dissolved in a solvent. The resist solution composition is applied onto a substrate such as a silicon wafer by a conventional method such as spin coating do. As the solvent to be used, it is possible to dissolve each of the above-mentioned components to provide a uniform and smooth coating film having a proper drying rate and evaporating the solvent. A solvent commonly used in this field can be used.

Examples of such a solvent include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; Acyclic esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; And cyclic esters such as ketone: gamma -butyrolactone such as acetone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone. These solvents may be used alone or in combination of two or more.

The resist film which is applied on the substrate and then dried is subjected to an exposure treatment for patterning, followed by a heat treatment for promoting the reaction of the deprotection, followed by development with an alkaline developer. The alkali developing solution to be used may be any one of various alkaline aqueous solutions used in this field. In general, aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly referred to as choline) are often used.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In the examples,% and parts representing the content or amount are based on weight unless otherwise specified. The weight average molecular weight of the obtained resin was determined by gel permeation chromatography (apparatus: HLC-8120GPC manufactured by TOSOH CORPORATION; column: Multipore HXL-M manufactured by TOSOH CORPORATION) using polystyrene as a standard product.

Synthesis Example 1 <Synthesis of Polymer R1>

(LIGHT-ESTER) 130MA (R ¹ is a methyl group, R ² is a group of the formula (2), R ³ is an ethylene group, 29.8 g of a compound represented by the general formula (1) wherein R ⁴ is a methyl group and n is about 9, 45.2 g of diethylene glycol monomethyl ether methacrylate and 0.4 g of 2,2'-azobisisobutyronitrile are dissolved in 59 g of dioxane And dissolved to obtain a solution.

A four-necked flask equipped with a stirrer, a reflux condenser and a thermometer was charged with 118 g of dioxane, and the mixture was adjusted to 77 DEG C, and then the solution was added dropwise over 1 hour. The resulting mixture was stirred at the same temperature for a further 10 hours. After the obtained reaction mixture was cooled, 130 g of dioxane was added, and the obtained mixture was poured into a mixed solution of 600 g of methanol and 900 g of water. The precipitated polymer was taken out and dissolved in propylene glycol monomethyl ether acetate. The obtained solution was concentrated to obtain a polymer solution having a solid content of 40%. The weight average molecular weight of the obtained polymer was 160,000. The resulting polymer is referred to as polymer R1.

Synthesis Example 2 < Synthesis of Polymer R2 >

A polymer having a weight average molecular weight of 160,000 was obtained in the same manner as in Synthesis Example 1 except that 54.7 g of 1-ethylcyclopentyl methacrylate was used instead of 42.7 g of tert-butyl methacrylate. The resulting polymer is referred to as polymer R2.

Synthesis Example 3 < Synthesis of Polymer R3 >

A polymer having a weight average molecular weight of 51,000 was obtained in the same manner as in Synthesis Example 1, except that 74.5 g of 2-ethyl-2-adamantyl methacrylate was used instead of 42.7 g of tert-butyl methacrylate. . The resulting polymer is abbreviated as polymer R3.

Synthesis Example 4 < Synthesis of Polymer R4 >

A four-necked flask equipped with a stirrer, a reflux condenser and a thermometer was charged with 413.5 g of 2,5-xylenol, 103.4 g of o-hydroxybenzaldehyde, 20.1 g of p-toluenesulfonic acid and 826.9 g of methanol, Was refluxed for 4 hours. After cooling the reaction mixture, 1320 g of methyl isobutyl ketone was added. Under atmospheric pressure, the obtained mixture was concentrated, and 1075 g of methyl isobutyl ketone was distilled off. To the obtained concentrated solution, 762.7 g of m-cresol and 29.0 g of tert-butyl-5-methylphenol were added and the temperature was raised to 65 ° C. To the obtained mixture, 678 g of 37% formalin was added dropwise over 1.5 hours while adjusting the temperature to 87 캜 at the end of the dropwise addition, and the mixture was kept at 87 캜 for 10 hours. To the reaction mixture, 1115 g of methyl isobutyl ketone was added and the mixture was washed three times with ion-exchanged water. To the resulting polymer solution, 500 g of methyl isobutyl ketone was added and the mixture was concentrated under a current pressure to obtain 3435 g of a concentrated solution. To the obtained concentrated solution, 3796 g of methyl isobutyl ketone and 4990 g of n-heptane were added, and the mixture was stirred at 60 ° C for 1 hour. After standing, the polymer-containing layer in the lower layer was separated. The polymer-containing layer was diluted with 3500 g of propylene glycol monomethyl ether acetate and then concentrated to obtain 1690 g of a novolac polymer-containing solution. The weight average molecular weight of the obtained novolak polymer was 7,000. The resultant novolak polymer is abbreviated as polymer R4.

Synthesis Example 5 < Synthesis of Polymer R5 >

A polymer solution having a solid content of 38% was obtained in the same manner as in Synthesis Example 1 except that the amount of 2,2'-azobisisobutyronitrile used was changed to 0.25 g. The weight average molecular weight of the obtained polymer was 250,000. The resulting polymer is abbreviated as Polymer R5.

Synthesis Example 6 <Synthesis of Polymer R6>

A polymer solution having a solid content of 33% was obtained in the same manner as in Synthesis Example 1 except that the amount of 2,2'-azobisisobutyronitrile used in Synthesis Example 1 was changed to 0.74 g. The weight average molecular weight of the obtained polymer was 80,000. The resulting polymer is abbreviated as Polymer R6.

Synthesis Example 7 <Synthesis of Polymer R7>

20.5 g of tert-butyl methacrylate, 47.7 g of the same LIGHT-ESTER 130MA as used in Synthesis Example 1, 45.2 g of diethylene glycol monomethyl ether methacrylate, and 20 g of 2,2'-azobisisobutylo 0.32 g of nitrile was dissolved in 59 g of dioxane to obtain a solution.

A four-necked flask equipped with a stirrer, a reflux condenser and a thermometer was charged with 118 g of dioxane, and the mixture was adjusted to 77 DEG C, and then the solution was added dropwise over 1 hour. The resulting mixture was stirred at the same temperature for a further 10 hours. After the obtained reaction mixture was cooled, 130 g of dioxane was added, and the obtained mixture was poured into a mixed solution of 600 g of methanol and 1600 g of water. The precipitated polymer was taken out and dissolved in propylene glycol monomethyl ether acetate. The obtained solution was concentrated to obtain a polymer solution having a solid content of 38%. The weight average molecular weight of the obtained polymer was 150,000. The obtained polymer is abbreviated as polymer R7.

Examples 1 to 3 and Comparative Examples 1 to 3

Next, examples in which a resist composition is prepared using each of the polymers, acid generators and quenchers shown below, and evaluation is shown.

<Acid Generator>

S1: N-trifluoromethylsulfonyloxy-1,8-naphthalimide

S2: (2- (4-methylphenyl) sulfonyloxyimino-2H-thiophen-3-ylidene) - (2- methylphenyl) acetonitrile

<Kenter>

Q: Dicyclohexylmethylamine

<Solvent>

Propylene glycol monomethyl ether acetate 25 parts

The following components were mixed and dissolved, and the resulting solution was filtered through a fluororesin filter having a pore diameter of 5 탆 to prepare a resist solution.

The polymer (type and amount used are listed in Table 1)

The acid generator (type and amount used are listed in Table 1)

Kinder (type and amount used are listed in Table 1)

The prepared resist solution was spin-coated on a silicon wafer so that the film thickness after drying was 20 占 퐉. After the resist solution was applied, it was prebaked on a hot plate at 130 DEG C for 5 minutes. Each wafer on which a resist film was formed in this manner was exposed to a line-and-space pattern by changing the exposure amount stepwise by using an i-line stepper "NSR 1755i7A" (NA = 0.5) manufactured by Nikon Corporation.

After exposure, post exposure baking was performed on a hot plate at 100 DEG C for 5 minutes, and paddle development was further performed three times with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 100 seconds.

The dark field pattern after development was observed with a scanning electron microscope, and the results are shown in Table 2. The dark field pattern referred to herein is obtained by exposure and development through a reticle in which a glass layer (light-transmitting layer) is formed in a line on the outer side with a chromium layer (light-shielding portion) as a base, A pattern in which the resist layer around the line and space pattern is left.

Effective sensitivity: Represented by an exposure dose at which a line-and-space pattern of 20 탆 was 1: 1.

Resolution: A line-and-space pattern of 4 m was not resolved at an exposure amount of 1: 1 in a line-and-space pattern of 20 m, and X was resolved.

Pattern profile: In a line and space pattern of 20 占 퐉, the top portion of the line portion was?, The top portion was rounded, and the top portion was rounded?.

Claims (8)

(A) derived from a tertiary butyl acrylate or tertiary butyl methacrylate and a polymerization unit (b) derived from a compound of the general formula (1), wherein the content of the polymerized units (a) (A), the polymer (B) soluble in alkali, and the acid generator (C) in an amount of 70 to 70 mol%, the content of the polymerized unit (b) is 30 to 90 mol%, the weight average molecular weight in terms of polystyrene is 50,000 to 300,000 Wherein the photoresist composition is a positive resist composition. Formula 1

In the above formula (1) R ¹ is a hydrogen atom or a methyl group, R ² is a group of formula (2). (2)

In the above formula (2) R ³ is an alkylene group having 1 to 6 carbon atoms, R ⁴ is an alkyl group having 1 to 6 carbon atoms, n is an integer of 1 to 30; delete delete The positive resist composition according to claim 1, wherein the alkali-soluble polymer is a novolac polymer. The positive resist composition according to claim 1, wherein the alkali-soluble polymer is a polymer containing a polymerized unit derived from hydroxystyrene. The positive resist composition according to claim 1, wherein the acid generator is a salt of the formula (3) or a compound of the formula (4). (3)

Formula 4

In the above formulas (3) and (4) A is an oxygen atom or a sulfur atom, R ⁵ and R ⁶ are the same or different and are each independently a methyl group or a phenyl group, R ⁷ and R ⁸ are each a perfluoroalkyl group having 1 to 8 carbon atoms. The positive resist composition according to claim 1, further comprising a basic compound. (A) derived from a tertiary butyl acrylate or tertiary butyl methacrylate and a polymerization unit (b) derived from a compound of the general formula (1), wherein the content of the polymerized units (a) , The content of the polymeric unit (b) is 30 to 90 mol%, and the weight average molecular weight in terms of polystyrene is 50,000 to 300,000. Formula 1

In the above formula (1) R ¹ is a hydrogen atom or a methyl group, R ² is a group of formula (2). (2)

In the above formula (2) R ³ is an alkylene group having 1 to 6 carbon atoms, R ⁴ is an alkyl group having 1 to 6 carbon atoms, n is an integer of 1 to 30;