JPH09160244A - Radiation sensitive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compsn. effectively sensitive to various radiations, having satisfactory resolution, pattern shape and PED stability and low dependency on baking temp., excellent also in process stability and useful as a chemically amplified positive resist by incorporating a polymer having substituents each having a t-butyl group cleavable by an acid, a polymer having acetal or ketal groups and a radiation sensitive acid generating agent. SOLUTION: This compsn. contains a polymer having substituents each having a t-butyl group cleavable by an acid, a compd. having acetal or ketal groups decomposable by the acid and a radiation sensitive acid generating agent. This compsn. is excellent in PED stability as well as excellent especially in resolution and pattern shape, has low dependency on baking temp., is excellent in process stability and can stably form a high precision fine pattern.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a radiation-sensitive composition. More specifically, it relates to a radiation-sensitive composition useful as a resist suitable for fine processing using various radiations such as ultraviolet rays, far ultraviolet rays, X-rays, and charged particle beams.

[0002]

2. Description of the Related Art In the field of microfabrication represented by the manufacture of integrated circuit devices, miniaturization of design rules in lithography is rapidly progressing in order to obtain higher integration of integrated circuits. The development of a lithography process capable of stably performing high-precision fine processing with a line width of 0.5 μm or less is strongly promoted.
However, conventional visible light (wavelength 700-400n
It is difficult to form such a fine pattern with high accuracy by the method using m) or near-ultraviolet light (wavelength 400 to 300 nm). Therefore, it is possible to achieve a wider depth of focus, and it is effective for the miniaturization of design rules. Short wavelength (wavelength 3
A lithography process using radiation of less than or equal to 00 nm has been proposed.

Examples of the lithography process using such short-wavelength radiation include deep ultraviolet rays such as KrF excimer laser (wavelength 248 nm) and ArF excimer laser (wavelength 193 nm), X-rays such as synchrotron radiation, and electron beams. Methods using charged particle beams have been proposed. And as a high-resolution resist corresponding to these short wavelength radiation,
A "chemical amplification type resist" has been proposed by Business Machines (IBM), and at present, improvement of this chemical amplification type resist is energetically advanced.

In such a chemically amplified resist, an acid is generated by irradiating a radiation-sensitive acid generator contained therein with radiation (hereinafter referred to as "exposure"), and the resist film is formed by the catalytic action of this acid. In this, a pattern is formed by utilizing a phenomenon in which a chemical reaction (for example, change in polarity, decomposition of chemical bond, cross-linking reaction, etc.) is caused and solubility in a developing solution is changed in an exposed portion.

Among the conventional chemically amplified resists having relatively good resist performance, the alkali-affinity group in the alkali-soluble resin is a t-butyl ester group or a t-butoxycarbonyl group as a resin component. Contains a protected resin (see JP-B-2-27660), a resin in which an alkali-affinity group in an alkali-soluble resin is protected with a silyl group (see JP-B-3-44290), and a (meth) acrylic acid component. Resin (see Japanese Patent Publication No. 4-39665), a resin component in which an alkali-affinity group in an alkali-soluble resin is protected with a ketal group (Japanese Patent Laid-Open No. 7-18753).
-140666), a resin protected with an acetal group (JP-A-2-161436 and JP-A-5-161436).
A resist using 249682) is known.

However, it has been pointed out that each of these chemically amplified resists has its own problems, and various difficulties are involved in putting it into practical use.

A major problem is that the line width of the resist pattern may change or the T-shape may be formed depending on the leaving time from exposure to post bake (hereinafter referred to as "PED"). To be Further, in addition to the pattern shape, the line width change of the resist pattern due to PED, etc., the resolution, the baking temperature dependency, etc. are large, the process stability is insufficient, and further improvement is required from the viewpoint of overall characteristics as a chemically amplified resist. Has been.

[0008]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention has been made as a result of further detailed study of a polymer component constituting a chemically amplified resist. That is, the object of the present invention is ultraviolet rays, far ultraviolet rays,
Effectively sensitive to various kinds of radiation such as X-rays or valence electrons, and excellent in resolution, pattern shape, PED stability, etc.
It is an object of the present invention to provide a radiation-sensitive composition useful as a chemically amplified positive resist, which has a small baking temperature dependency and an excellent process stability.

[0009]

According to the present invention, the object is to provide a polymer (A) having a substituent having a t-butyl group which can be cleaved by an acid (hereinafter referred to as "polymer (A)"). And (B) a compound having an acetal group or a ketal group that can be decomposed by an acid (hereinafter referred to as “polymer (B)”) and (C) a radiation-sensitive resin composition containing a radiation-sensitive acid generator. To be done. BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below, which will clarify the objects, configurations and effects of the present invention.

The substituent having a t-butyl group which can be decomposed by the polymer (A) acid is, for example, --C (CH ₃ ) ₃ or --C (═O)-OC (CH.
_{3) 3, -CH 2 C (} = O) -OC (CH 3) 3, -C (-
_{CH 3) H-C (=} O) OC (CH 3) 3, -C (CH 3)
_{2 -C (= O) O (} CH 3) 3 and the like.

As such a polymer (A), for example, the following formula (1)

[0012]

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Here, R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom or a methyl group, R ₅ is a substituent having a t-butyl group which can be decomposed by an acid, R ₆
Is a hydrogen atom, a methyl group, an ethyl group, a substituent having an acid-decomposable t-butyl group, a cycloalkyl group, a haloalkyl group, a (poly) oxyalkylene group, an aryl group or an aralkyl group, and R ₇ is halogen. An atom, a hydroxyl group, a linear or branched alkyl group having 1 to 12 carbon atoms or an aryl group, and R ₈ is a hydrogen atom or-
A group represented by CO ₂ R ₆ , wherein 0 ≦ l ≦ 100, 0 ≦
n ≦ 100, 0 ≦ m <100 and 0 ≦ o <100. However, l and n are not 0 at the same time, and usually l
+ N ≧ 5, preferably l + n ≧ 10, and l + n + m
When + o = 100 and l is 0, R ₆ is a substituent having an acid-decomposable butyl group,

Examples thereof include polymers having at least one repeating unit represented by the formula (1):
A polymer in which at least two kinds of repeating units represented by are randomly bonded is preferable.

In the above formula (1), specific examples of the substituent having a t-butyl group which can be decomposed by the acid of R ₅ and R ₆ are -C (CH ₃ ) ₃ and -C (= O) OC. (C
_{H 3) 3, -CH 2 CO} 2 C (CH 3) 3, -CH (CH 3)
_{CO 2 C (CH 3) 3} , -C (CH 3) 2 CO 2 C (CH 3) 3
Can be mentioned. Of these, R ₅ is-
C (= O) OC (CH 3) 3 is preferable, as R ₆ -
C (CH ₃ ) ₃ is preferred.

In the above formula (1), examples of the cycloalkyl group of R ₆ include cyclohexyl group and isobornyl group, and examples of the haloalkyl group of R ₆ include trifluoroethyl group and hexafluoropropyl group. , A heptadecafluorodecyl group and the like, and the (poly) oxyalkylene group of R ₆ includes
Examples thereof include a phenoxy polyethylene glycol group and a phenoxy ethylene glycol group. Examples of the aryl group of R ₆ include phenyl group and tolyl group. Examples of the aralkyl group of R ₆ include benzyl group, Examples thereof include a phenethyl group.
Of these, R ₆ is preferably a substituent having a t-butyl group.

Further, in the above formula (1), examples of the halogen atom for R ₇ include fluorine, chlorine, bromine, etc., and a straight or branched chain of R ₇ having 1 to 12 carbon atoms. Examples of the alkyl group include a methyl group, a t-butyl group, an isobutyl group, a pentyl group, an octyl group, a dodecyl group, a cetyl group, and a stearyl group. Examples of the aryl group of R ₇ include phenyl. Group, tolyl group and the like. Of these, a phenyl group is preferred as R ₇ .

The polymer having at least one repeating unit represented by the above formula (1) can be produced, for example, as follows. (I) The following formula (1) -a

[0019]

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The definition of R ₂ is the same as in the above formula (1), and a polymer of a monomer represented by, for example, poly (p
-Hydroxystyrene), poly (p-isopropenylphenol) and the like, or a compound which converts all or a part of hydroxyl groups into a substituent having a t-butyl group which can be decomposed by an acid,
For example, by reacting with t-butyl bromoacetate, di-t-butyl carbonate, etc., the repeating unit having R ₁ and R ₂
A polymer consisting of repeating units having

(Ii) A monomer represented by the above formula (1) -a, for example, p-hydroxystyrene, p-isopropenylphenol, etc., is added to the following formula (1) -b.

[0022]

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The definitions of R ₃ , R ₆ and R ₈ are the same as those in the above formula (1), for example, t-butyl acrylate, fumaric acid (t-butyl), isobornyl acrylate and / Or the following formula (1) -c

[0024]

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Here, R ₁ and R ₅ are defined by the above formula (1).
Which is the same, a compound represented by, for example t- butoxystyrene and by copolymerizing, consisting of repeating units and / or repeating units having the R ₁ having the R ₃ and repeating units having the R ₂ A polymer is produced.

(Iii) In the above (i), the formula (1)
The following formula (1) -d is used during the production of the polymer of the monomer of -a or during the polymerization of (ii) above.

[0027]

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Here, the definitions of R ₄ and R ₇ are defined by the above formula (1).
Is copolymerized with a compound represented by the formula (1) to produce a polymer further containing the repeating unit having R ₄ .
The polystyrene reduced weight average molecular weight (hereinafter referred to as “Mw”) of the polymer (A) produced as described above is usually 1,000 to 100,000, and preferably 3.0.
The number average molecular weight in terms of Mw / polystyrene (hereinafter referred to as "Mn") is usually 1 to 3, and preferably 1 to 2.5. These polymers (A) may be used alone or in admixture of two or more.

Examples of the acetal group which can be decomposed by the polymer (B) acid include groups represented by the following formula (2) or the following formula (3).

[0030]

[Chemical 6]

In the formula (2), X ₁ and X ₂ are a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or 7 to 7 carbon atoms. 11 represents an aralkyl group, at least one of X ₁ and X ₂ is a hydrogen atom, and X ₃ has 1 carbon atom.
It represents an alkyl group having 10 to 10, an aryl group having 6 to 10 carbons, or an aralkyl group having 7 to 11 carbons.

[0032]

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In the formula (3), X ₄ and X ₅ represent a hydrogen atom, an alkoxy group having 1 to 3 carbon atoms or an alkyl group having 1 to 6 carbon atoms. Examples of the ketal group that can be decomposed by an acid include groups represented by the following formula (4) or the following formula (5).

[0034]

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In the formula (4), Y ₁ and Y ₂ may be the same or different, and are an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and 6 to 1 carbon atoms.
0 represents an aryl group or an aralkyl group having 7 to 11 carbon atoms, or Y ₁ and Y ₂ are bonded to each other to form a 3 to 7 membered ring together with the carbon atom to which they are bonded. May be. Y ₃ represents an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 6 to 10 carbon atoms.

[0036]

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In the formula (5), Y ₄ and Y ₅ represent a hydrogen atom, an alkoxy group having 1 to 3 carbon atoms or an alkyl group having 1 to ₆ carbon atoms, Y ₆ is an alkyl group having 1 to ₆ carbon atoms, Aryl group having 6 to 10 carbon atoms or 6 to 10 carbon atoms
Represents an aralkyl group of.

Examples of the alkyl group having 1 to 10 carbon atoms of X ₁ and X ₂ in the above formula (2) include methyl group, ethyl group, propyl group, isopropyl group, isobutyl group, pentyl group, hexyl group, heptyl group, Examples thereof include an octyl group, a 2-ethylhexyl group and a neopentyl group. Examples of the cycloalkyl group having 3 to 10 carbon atoms for X ₁ and X ₂ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a norbornyl group and an isobornyl group. Examples of the aryl group having 6 to 10 carbon atoms for X ₁ and X ₂ include a phenyl group, a tolyl group, a xylyl group and a naphthyl group. 7 to 11 carbon atoms of X ₁ and X ₂
The aralkyl group of is a benzyl group, a phenethyl group,
A naphthomethyl group etc. can be mentioned.

1 to 1 carbon atoms of X ₃ in the above formula (2)
As the alkyl group having 0, the aryl group having 6 to 10 carbon atoms or the aralkyl group having 7 to 11 carbon atoms, the same groups as those mentioned for X ₁ and X ₂ can be mentioned as specific examples.

Examples of the alkoxy group having 1 to 3 carbon atoms of X ₄ and X ₅ in the above formula (3) include a methoxy group, an ethoxy group and a propoxy group, and an alkyl group having 1 to 6 carbon atoms is methyl. Group, ethyl group, propyl group, isopropyl group, butyl group, pentyl group, hexyl group and the like.

In the above formula (4), Y ₁ and Y _{2 have} an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or 7 to 7 carbon atoms.
As the aralkyl group of 10, the same groups as those mentioned for X ₁ and X ₂ can be mentioned as specific examples.

1 to 1 carbon atoms of Y ₃ in the above formula (4)
As the alkyl group having 0, the aryl group having 6 to 10 carbon atoms or the aralkyl group having 7 to 11 carbon atoms, the same groups as those mentioned for X ₁ and X ₂ can be mentioned as specific examples.

As the alkyl group having 1 to 6 carbon atoms or the alkoxy group having 1 to 3 carbon atoms of Y ₄ and Y ₅ in the above formula (5), the same groups as those mentioned for X ₄ and X ₅ are mentioned as specific examples. be able to.

Y in the above equation (6)₆1 to 6 carbon atoms
The alkyl group of is X_FourAnd X _FiveSame as listed in
The same group can be mentioned as a specific example. Formula (6) above
At Y₆An aryl group having 6 to 10 carbon atoms or carbon
Examples of the aralkyl group of the formulas 6 to 10 include X₁And
And X_TwoSpecific examples of the same groups listed in
Can be.

Examples of the acetal group include methoxymethoxy group, ethoxymethoxy group, 1-methoxyethoxy group, 1-ethoxyethoxy group, 1-propoxyethoxy group, 1-isopropoxyethoxy group, benzyloxymethoxy group, 1- Examples thereof include a benzyloxymethoxy group, a phenethyloxymethoxy group, a 1-phenethyloxyethoxy group, a 2-tetrahydrofuranyloxy group and a 2-tetrahydropyranyloxy group.

Examples of the ketal group include 1-methoxy-1-methylethoxy group, 1-phenyl-1-methoxyethoxy group, 1-phenyl-1-ethoxyethoxy group, 1-benzyl-1-methoxyethoxy group, 2- (2
-Methyl-tetrahydropyranyl) oxy group, 2- (2
-Methyl-tetrahydrofuranyl) oxy group, 1- (1
Examples include -methoxy-cyclohexyl) oxy group and 1-phenoxy-1-phenylethoxy group.

As the polymer (B), for example, the following formula (6) is used.

[0048]

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Where R ₉ , R ₁₀ , R ₁₁ and R ₁₂ are
Independently of each other, a hydrogen atom or a methyl group, R ₁₃ is an acetal group or a ketal group, R ₁₄ is a hydrogen atom, a methyl group, an ethyl group, an acetal group, a ketal group,
A cycloalkyl group, a haloalkyl group, a (poly) oxyalkylene group, an aryl group or an aralkyl group, and R
The definitions of ₁₅ and R ₁₆ are the same as the definitions of R ₆ , R ₇ and R ₈ , respectively, and 0 ≦ p ≦ 100, 0 ≦ r ≦ 100, 0
≦ q <100 and 0 ≦ s <100. Where p and r
Are not 0 at the same time, usually p + r ≧ 10, preferably p + r ≧ 25, and p + r + q + s = 1
00, and when p is 0, R ₁₄ is an acetal group or a ketal group.
Examples thereof include a polymer having two kinds of repeating units, and a polymer in which at least two kinds of repeating units represented by the above formula (6) are randomly bonded is particularly preferable.

In the above formula (6), as the acetal group or ketal group of R ₁₃ , the same groups as those mentioned above can be exemplified, and the respective specific examples of R ₁₄ , R ₁₅ and R ₁₆ are also the above. It will be clear from the examples of R ₆ , R ₇ and R _{8 mentioned above} .

The polymer having at least one repeating unit represented by the above formula (6) can be produced, for example, as follows. (I) Polymers of monomers represented by the above formula (1) -a, such as poly (p-hydroxystyrene) and poly (p
-Isopropenylphenol) and the like, and all or a part of the hydroxyl groups thereof, such as ethyl vinyl ether,
Etherifying by reacting with a compound such as 2,3-dihydropyran, 4-methoxy-5,6-dihydro-2H-pyran or 2-methoxypropylene, and repeating unit having the above R ₉ and repeating unit having the above R _10. To produce a polymer consisting of

(Ii) In the above (i), the formula (1)-
In producing a polymer of the monomer represented by a, a compound represented by the following formula (6) and / or the formula (1) -d is copolymerized to give a repeating unit having the above R ₁₁ and / or the above A polymer is prepared which further contains repeating units with R ₁₂ .

Polymer (B) produced as described above
Mw is usually 1,000 to 100,000, preferably 3,000 to 40,000, and Mw / Mn is
It is usually 1 to 3, preferably 1 to 2.5. These polymers (B) may be used alone or in admixture of two or more.

In the present invention, the ratio of the polymer (A) to the polymer (B) used is preferably such that the weight ratio of the polymer (A) to the polymer (B) is 1/99 to 99/1. , 50 /
It is more preferably 50 to 10/90.

Radiation-sensitive acid generator The radiation-sensitive acid generator is a compound that generates an acid upon exposure. Examples of the radiation-sensitive acid generator used in the present invention include onium salts, halogen-containing compounds,
Examples thereof include a sulfone compound, a sulfonic acid ester compound, a quinonediazide compound, a sulfonimide compound, and a diazomethane compound. Examples of these radiation-sensitive acid generators are shown below.

Onium salts: Examples of onium salts include iodonium salts, sulfonium salts, phosphonium salts,
Examples thereof include diazonium salts, ammonium salts, pyridinium salts and the like. Specific examples of the onium salt compound include diphenyliodonium triflate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium hexafluoroantimonate, triphenylsulfonium naphthalene Sulfonate, triphenylsulfonium camphorsulfonate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate and the like can be mentioned.

Halogen-containing compound: Examples of the halogen-containing compound include haloalkyl group-containing hydrocarbon compounds and haloalkyl group-containing heterocyclic compounds. Specific examples of the halogen-containing compound include (poly) such as phenyl-bis (trichloromethyl) -s-triazine, methoxyphenyl-bis (trichloromethyl) -s-triazine, and naphthyl-bis (trichloromethyl) -s-triazine. Trichloromethyl-s-triazine derivative, 1,1-bis (4-chlorophenyl) -2,
2,2-trichloroethane and the like can be mentioned.

Sulfone compound: Examples of the sulfone compound include β-ketosulfone, β-sulfonylsulfone, and α-diazo compounds thereof. Specific examples of the sulfone compound include phenacylphenylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane, 4-trisphenacylsulfone, and the like.

Sulfonic acid ester compound: Examples of the sulfonic acid ester compound include alkyl sulfonic acid ester, haloalkyl sulfonic acid ester, aryl sulfonic acid ester, imino sulfonate and the like. Specific examples of the sulfonic acid ester compound include benzoin tosylate, pyrogallol tris triflate, pyrogallol methanesulfonic acid triester,
Nitrobenzyl-9,10-diethoxyanthracene-
2-sulfonate etc. can be mentioned.

Quinonediazide compound: As the quinonediazide compound, 1,2-benzoquinonediazide-4-
Compounds having 1,2-quinonediazidesulfonyl group such as sulfonyl group, 1,2-naphthoquinonediazide-4-sulfonyl group, 1,2-naphthoquinonediazide-5-sulfonyl group, 1,2-naphthoquinonediazide-6-sulfonyl group And a compound having a 1,2-naphthoquinonediazide-4-sulfonyl group is particularly preferable.

Specific examples of the quinonediazide compound include:
2,3,4-trihydroxybenzophenone, 2,4,6-
Trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2 ', 3,4-tetrahydroxybenzophenone, 3'-methoxy-2,3,
4,4'-tetrahydroxybenzophenone, 2,2 ',
4,4'-tetrahydroxybenzophenone, 2,2 ',
3,4,4'-Petanehydroxybenzophenone, 2,
2 ', 3,4,6'-pentahydroxybenzophenone,
1,2 of (poly) hydroxyphenyl aryl ketones such as 2,3,3 ', 4,4', 5'-hexahydroxybenzophenone, 2,3 ', 4,4', 5 ', 6-hexahydroxybenzophenone -Quinone diazide sulfonic acid esters; bis (4-hydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) methane, bis (2,
3,4-trihydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (2,4-dihydroxyphenyl) propane, 2,2-bis (2,3,4-) 1,2 of bis [(poly) hydroxyphenyl] alkanes such as trihydroxyphenyl) propane
-Quinonediazide sulfonic acid esters; 4,4'-dihydroxytriphenylmethane, 4,4 ', 4 "-trihydroxytriphenylmethane, 2,2', 5,5'-tetramethyl-2", 4,4 '-Trihydroxytriphenylmethane, 3,3', 5,5'-tetramethyl-2 ", 4,
4'-trihydroxytriphenylmethane, 4,4 ',
5,5'-tetramethyl-2,2 ', 2 "-trihydroxytriphenylmethane, 2,2', 5,5'-tetramethyl-4,4 ', 4" -trihydroxytriphenylmethane, 1 , 1,1-Tris (4-hydroxytriphenyl)
Ethane, 1,1-bis (4-hydroxyphenyl) -1
-Phenylethane, 1,1-bis (4-hydroxyphenyl) -1- [4- {1- (4-hydroxyphenyl)
-1-Methylethyl} phenyl] ethane, 1,1,3-tris (2.5-dimethyl-4-hydroxyphenyl) propane, 1,1,3-tris (2.5-dimethyl-4-hydroxyphenyl) 1,2-quinonediazide sulfonic acid esters of (poly) hydroxytriphenylalkanes such as butane, 1,3,3-tris (4-hydroxyphenyl) butane; 2,4,4-trimethyl-2 ′, 4 ′, 7-trihydroxy-2-phenylflavan, 2,4,4-trimethyl-2 ', 4', 5 ', 6', 7-pentahydroxy-
Examples thereof include 1,2-quinonediazide sulfonic acid esters of (poly) hydroxyphenyl flavan such as 2-phenyl flavan.

Sulfonimide compound: As the sulfonimide compound, for example, the following formula (3)

[0063]

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Here, X represents a divalent group such as an alkylene group, an arylene group or an alkoxylene group, and R ₁₆ is a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group or a halogen-substituted aryl group. And a compound represented by.

Specific examples of the sulfonimide compound include:
N- (trifluoromethylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy)
Phthalimide, N- (trifluoromethylsulfonyloxy) diphenylmaleimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5
-Ene-2,3-dicarboximide, N- (trifluoromethylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (tri Fluoromethylsulfonyloxy) naphthylimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide, N- (camphorsulfonyloxy) succinimide, N- (camphorsulfonyloxy) phthalimide, N- (camphorsulfonyloxy) diphenylmaleimide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (Camphorsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarbo Shimido, N- (camphor-sulfonyloxy) naphthylimide, N- (camphorsulfonyloxy oxy) bicyclo [2.2.1] heptane-5,6-oxy-2,3-dicarboximide,

N- (4-methylphenylsulfonyloxy) succinimide, N- (camphanylsulfonyloxy) naphthyldicarboximide, N- (4-methylphenylsulfonyloxy) phthalimide, N- (4-methylphenylsulfonyloxy) Diphenylmaleimide, N- (4-methylphenylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (4-methylphenylsulfonyloxy) -7-oxabicyclo [2.2.1] Hept-5-ene-2,3-dicarboximide, N- (4-methylphenylsulfonyloxy) naphthylimide, N- (4-methylphenylsulfonyloxy) bicyclo [2.2. 1]
Heptane-5,6-oxy-2,3-dicarboximide,
N- (2-trifluoromethylphenylsulfonyloxy) succinimide, N- (2-trifluoromethylphenylsulfonyloxy) phthalimide, N- (2-trifluoromethylphenylsulfonyloxy) diphenylmaleimide, N- (2-trifluoro Methylphenylsulfonyloxy) bicyclo [2.2.1] hept-5-
Ene-2,3-dicarboximide, N- (2-trifluoromethylphenylsulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (2-Trifluoromethylphenylsulfonyloxy) naphthylimide, N- (2-trifluoromethylphenylsulfonyloxy) bicyclo [2.
2.1] Heptane-5,6-oxy-2,3-dicarboximide, N- (2-trifluoromethylphenylsulfonyloxy) naphthylimide, N- (4-fluorophenylsulfonyloxy) succinimide, N- ( 2-fluorophenyl) phthalimide, N- (4-fluorophenylsulfonyloxy) diphenylmaleimide, N-
(4-Fluorophenylsulfonyloxy) bicyclo [2.1.1] hept-5-ene-2,3-dicarboximide, N- (trifluoromethylsulfonyloxy)-
7-oxabicyclo [2.1.1] hept-5-ene-
2,3-dicarboximide, N- (4-fluorophenylsulfonyloxy) bicyclo [2.1.1] heptane-
5,6-oxy-2,3-dicarboximide, N- (4-
Examples thereof include fluorophenylsulfonyloxy) naphthyldicarboximide.

Diazomethane compound: Examples of the diazomethane compound include those represented by the following formula (4)

[0068]

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Here, R ₁₇ and R _{18, which} may be the same or different, each represents a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group or a halogen-substituted aryl group. Can be mentioned.

Specific examples of the diazomethane compound include bis (trifluoromethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, bis (phenylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, methylsulfonyl-p.
-Toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane and the like.

Among the above radiation-sensitive acid generators, onium salts, sulfonic acid ester compounds, sulfonimide compounds and diazomethane compounds are preferable, and particularly triphenylsulfonium triflate, pyrogallol methanesulfonic acid triester, N- (trifluoromethyl). Sulfonyloxy) bicyclo [2.2.1] hept-5
-Ene-2,3-dicarboximide, N- (camphanylsulfonyloxy) bicyclo [2.2.1] hept-5
-Ene-2,3-dicarboximide, N- (camphanylsulfonyloxy) naphthyldicarboximide, bis (cyclohexylsulfonyl) diazomethane and the like are preferable.

In the present invention, the above-mentioned radiation-sensitive acid generator is usually used in a total amount of 1 of the polymer (A) and the polymer (B).
It is used in a proportion of 0.1 to 20 parts by weight, particularly preferably 0.5 to 10 parts by weight, per 00 parts by weight. These radiation-sensitive acid generators are used alone or in combination of two or more.

Alkali-Soluble Resin In the present invention, an alkali-soluble resin other than the polymer (A) and the polymer (B) can be added if necessary. The alkali-soluble resin is a resin that is soluble in an alkali developer and has at least one kind of a functional group having an affinity for an alkali developer, such as a phenolic hydroxyl group or a carboxyl group. The use of such an alkali-soluble resin makes it easier to control the dissolution rate of the resist film of the composition of the present invention in an alkali developing solution, and as a result, the developability can be further improved.

Such an alkali-soluble resin is not particularly limited as long as it is soluble in an alkali developing solution, but preferable alkali-soluble resins include, for example, hydroxystyrene, isopropenylphenol, vinyl benzoic acid and carboxymethyl. Polymerizable double bond of at least one monomer having an acidic functional group such as styrene, carboxymethoxystyrene, (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, and cinnamic acid. Examples thereof include addition polymerization type resins containing a repeating unit in which a part is cleaved, polycondensation type resins containing a condensation type repeating unit having an acidic functional group represented by a novolak resin.

The alkali-soluble resin composed of the addition-polymerization resin may be composed of only repeating units in which the polymerizable double bond portion of the monomer having an acidic functional group is cleaved. As long as it is soluble in a liquid, it may further contain one or more other repeating units. Such other repeating units include:
For example, styrene, α-methylstyrene, vinyltoluene, maleic anhydride, (meth) acrylonitrile, crotonitrile, maleinitrile, fumaronitrile, mesaconitrile, citraconitrile, itaconitrile, (meth) acrylamide, crotonamide, maleamide, fumamide , Repeating units in which the polymerizable double bond portion of a monomer such as mesaconamide, citraconamide, itaconamide, vinylaniline, vinylpyridine, N-vinyl-ε-caprolactam, N-vinylpyrrolidone, or N-vinylimidazole is cleaved. Can be.

Among the above addition-polymerization resins, poly (hydroxystyrene) and isopropenylphenol copolymers are particularly preferable from the viewpoints of high radiation transmission when used as a resist film and excellent dry etching resistance. . Further, the alkali-soluble resin consisting of the polycondensation resin may be composed only of polycondensation repeating units having an acidic functional group, as long as the produced resin is soluble in an alkali developing solution, other It may further contain a repeating unit of. Such a polycondensation resin is, for example, one or more phenols and one or more aldehydes, optionally together with a polycondensation component capable of forming another polycondensation repeating unit, in the presence of an acidic catalyst. It can be produced by (co) polycondensation in an aqueous medium or in a mixed medium of water and a hydrophilic solvent.

Examples of the phenols include o-cresol, m-cresol, p-cresol and 2,3-
Xylenol, 2,4-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol,
2,3,5-trimethylphenol, 3,4,5-trimethylphenol and the like can be mentioned, and the aldehydes include, for example, formaldehyde, trioxane, paraformaldehyde, benzaldehyde, acetaldehyde, propylaldehyde, phenylacetaldehyde and the like. Can be mentioned. The alkali-soluble resins can be used alone or in combination of two or more. The amount of the alkali-soluble resin used in the present invention is usually 200 parts by weight or less per 100 parts by weight of the total of the polymer (A) and the polymer (B).

Acid Diffusion Control Agent An acid diffusion control agent can be added to the composition of the present invention.
This acid diffusion control agent has a function of controlling a diffusion phenomenon of an acid generated from a radiation-sensitive acid generator by exposure in a resist film, and suppressing an undesired chemical reaction in an unexposed region, By using the acid diffusion controller, it is possible to further improve the degree of generation of T-shape in the pattern shape of the composition of the present invention, the dimensional fidelity to the mask dimension, and the like.

As such an acid diffusion control agent, a nitrogen-containing organic compound whose basicity does not change by exposure or heating is preferable, and specific examples thereof include ammonia, hexylamine, heptylamine, octylamine, nonylamine,
Decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine,
Triheptylamine, trioctylamine, trinonylamine, tridecylamine, aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 1-naphthylamine, 2-naphthylamine, diphenylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, pyrrolidone,
Piperidine, imidazole, 4-methylimidazole,
4-methyl-2-phenylimidazole, thiabendazole, pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 1-
Methyl-4-phenylpyridine, 2- (1-ethylpropyl) pyridine, nicotinamide, dibenzoylthiamine, riboflavin tetrabutyrate, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,
4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4 -Aminophenyl)-
2- (3-hydroxyphenyl) propane, 2- (4-
Aminophenyl) -2- (4-hydroxyphenyl) propane, 1,4-bis [1- (4-aminophenyl)-
1-methylethyl] benzene, 1,3-bis [1- (4
-Aminophenyl) -1-methylethyl] benzene, dimethyl succinate-1- (2-hydroxyethyl) -4-
Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl } {(2,2,6,6-Tetramethyl-4-piperidiyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidiyl) imino}], 2- (3,5
-Di-t-butyl-4-hydroxybenzyl) -2-n
Bis (1,2,2,6,6-pentamethyl-4-piperidiyl) -butylmalonate and the like can be mentioned.

These acid diffusion control agents may be used alone or
A mixture of more than one species can be used. The blending ratio of the acid diffusion inhibitor in the present invention is usually 0.001-1 based on 100 parts by weight of the total of the polymer (A) and the polymer (B).
It is 0 part by weight, preferably 0.005 to 5 parts by weight. In this case, if the amount of the acid diffusion controlling agent used is less than 0.001 part by weight, the pattern shape and dimensional fidelity as a resist may be lowered depending on process conditions.
If it exceeds 0 parts by weight, the sensitivity as a resist and the developability of the exposed area tend to be lowered.

Surfactant As the surfactant to which the surfactant of the present invention can be added, there are polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether. , Polyoxyethylene nonylphenol ether, polyethylene glycol dilaurate, polyethylene glycol distearate. Examples of commercially available products include Ftop EF3.
01, EF303, EF352 (manufactured by Tochem Products), Megafax F171, F173 (manufactured by Dainippon Ink and Chemicals, Inc.), Florard FC430, FC431
(Manufactured by Sumitomo 3M Limited), Asahi Guard AG71
0, Surflon S-382, SC101, SC102,
SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer KP34
1 (manufactured by Shin-Etsu Chemical Co., Ltd.), an acrylic acid-based or methacrylic acid-based (co) polymer, Polyflow No. 75, N
O.95 (trade name, manufactured by Kyoeisha Oil and Fat Chemical Co., Ltd.) and the like are used.

The blending amount of the surfactant is 100 in total with the polymer (A), the polymer (B) and the radiation-sensitive acid generator.
It is usually 2 parts by weight or less per part by weight.

Sensitizer A sensitizer can be added to the composition of the present invention. This sensitizer has the function of absorbing the energy of radiation and transmitting the energy to the radiation-sensitive acid generator, thereby increasing the amount of acid produced, and is formed by the resin composition of the present invention. It has the effect of improving the apparent sensitivity of the resist. Examples of preferred sensitizers include acetone, benzene, acetophenones, benzophenones,
Examples thereof include naphthalene, biacetyl, eosin, rose bengal, pyrene, anthracene, and phenothiazine. These sensitizers can be used alone or in admixture of two or more, and the compounding amount thereof is usually 50 per 100 parts by weight of the total solid content in the composition.
It is not more than 30 parts by weight, preferably not more than 30 parts by weight.

Other Additives In the composition of the present invention, by blending a dye and / or a pigment, the latent image in the exposed area can be visualized to mitigate the effect of halation during exposure, and an adhesion aid is blended. Thereby, the adhesiveness with the substrate can be further improved.
Further, as other additives, an antihalation agent such as 4-hydroxy-4′-methylchalcone, a shape improving agent, a storage stabilizer, an antifoaming agent and the like can be added.

Solvent The composition of the present invention, when used, is uniformly dissolved in the solvent so that the concentration of the total solid content is, for example, 5 to 50% by weight, preferably 15 to 40% by weight. By filtering with a filter of about 0.2 μm,
Prepared as a composition solution.

Examples of the solvent used for preparing the composition solution include ethylene glycol such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether. Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate Diethylene glycol dimethyl ether,
Diethylene glycol dialkyl ethers such as diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether; propylene glycol monomethyl ether,
Propylene glycol monoalkyl ethers such as propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether; propylene glycol dimethyl ether
Propylene glycol dialkyl ethers such as ter, propylene glycol diethyl ether, propylene glycol dipropyl ether, propylene glycol dibutyl ether;

Propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, and other propylene glycol monoalkyl ether acetates; lactic acid Methyl, ethyl lactate, lactate n
-Lactic acid esters such as propyl, isopropyl lactate, n-butyl lactate, isobutyl lactate; methyl formate, ethyl formate, n-propyl formate, isopropyl formate, n-butyl formate, isobutyl formate, n-amyl formate, isoamyl formate, acetic acid Methyl, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, n-hexyl acetate, methyl propionate, ethyl propionate, n-propionate
-Propyl, isopropyl propionate, n-butyl propionate, isobutyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, n-butyl butyrate, isobutyl butyrate and other aliphatic carboxylic acid esters;

Ethyl hydroxyacetate, 2-hydroxy-
Ethyl 2-methylpropionate, 2-hydroxy-3-
Methyl methylbutyrate, ethyl methoxyacetate, ethyl ethoxyacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 3-methoxybutylacetate, 3-methyl- 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, methyl acetoacetate, ethyl acetoacetate, methyl pyruvate,
Other esters such as ethyl pyruvate; aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone; N -Methylformamide, N, N-dimethylformamide, N-methylacetamide, N, N
Amides such as -dimethylacetamide and N-methylpyrrolidone; and laclones such as γ-butyrolactone.

These solvents can be used alone or in admixture of two or more, and the compounding amount thereof is usually 20 to 3, per 100 parts by weight of the total solid content in the composition of the present invention.
000 parts by weight, preferably 50 to 3,000 parts by weight, more preferably 100 to 2,000 parts by weight.

Formation of Resist Pattern When forming a resist pattern from the composition of the present invention,
The composition solution prepared as described above, spin coating, cast coating, by a suitable coating means such as roll coating, for example, a silicon wafer, by coating on a substrate such as a wafer coated with aluminum, A resist film is formed and, if necessary, a heat treatment (hereinafter referred to as "prebaking") is performed in advance, and then exposure is performed through a predetermined mask pattern. The radiation used at that time is, for example, ultraviolet rays such as i-line (wavelength 365 nm); ArF excimer laser (wavelength 193 nm), KrF excimer laser (wavelength 248 nm), etc. depending on the type of the radiation-sensitive acid generator. Far ultraviolet rays; X-rays such as synchrotron radiation; charged particle beams such as electron beams are appropriately selected for use.
The exposure conditions such as the exposure dose are appropriately selected according to the composition of the composition of the present invention, the type of each additive, and the like.

In the present invention, in order to improve the apparent sensitivity of the resist film, a heat treatment after exposure (hereinafter, referred to as
It is called "post-exposure bake". ) Is preferable. The heating condition varies depending on the composition of the composition of the present invention, the type of each additive, and the like, but is usually 30 to 200 ° C, preferably 40 to 150 ° C. Next, the exposed resist film is subjected to alkali development with an alkali developer,
A predetermined resist pattern is formed.

Examples of the alkaline developer include alkali metal hydroxides; ammonia water; mono-, di- or tri-alkylamines; mono-, di- or tri-alkanolamines; heterocyclic amines; Tetraalkylammonium hydroxides; choline; 1,8-
Diazabicyclo- [5.4.0] -7-undecene, 1,
An alkaline aqueous solution in which an alkaline compound such as 5-diazabicyclo- [4.3.0] -5-nonene is dissolved to a concentration of usually 1 to 10% by weight, preferably 1 to 5% by weight is used. . These alkaline compounds can be used alone or in combination of two or more. In addition, a water-soluble organic solvent such as methanol or ethanol, or a surfactant may be appropriately added to the developer containing the alkaline aqueous solution. When a developer composed of an alkaline aqueous solution is used, washing is generally performed after development. In forming the resist pattern, a protective film may be provided on the resist film in order to prevent the influence of basic impurities and the like contained in the environmental atmosphere.

[0093]

The present invention will be described below more specifically with reference to examples and comparative examples. However, the present invention is not limited to these embodiments. Here, the measurement of Mw and Mn (Mw / Mn) and the evaluation of each resist were performed as follows.

Mw and Mw / Mn Tosoh Corp. GPC column (G2000HXL 2 pieces,
G3000HXL 1 piece, G4000HXL 1 piece),
The flow rate was 1.0 ml / min, the elution solvent was tetrahydrofuran, and the column temperature was 40 ° C.

Sensitivity A resist film formed on a silicon wafer was exposed, and immediately after-exposure baking was performed, followed by alkali development, followed by washing with water and drying to form a resist pattern. The exposure amount for forming a line-and-space pattern (1L1S) with a line width of 1: 1 was taken as the optimum exposure amount, and the sensitivity was evaluated by this optimum exposure amount.

Resolution The minimum dimension (μm) of the resist pattern resolved when exposed with the optimum exposure amount was taken as the resolution.

In the line-and-space pattern having a pattern shape of 0.3 μm, the line width of the upper part of the pattern is La and the line width of the lower part of the pattern is Lb, and 0.9 × Lb <La <1.1 × Lb is preferable. , 0.9 × Lb ≧ La, round top, La
The case of ≧ 1.1 × Lb was represented as T-type.

PED Stability The line width of the lower part of the pattern when PED is 0 hour is X _0, and the line width of the lower part of the pattern when PED is 1 hour is X ₁
Then, the line width change rate represented by the following formula was determined. The closer the value is to 0, the better the PED stability.

[0099]

[Equation 1]

Synthesis of Polymer (A) Synthesis Example 1 Poly (p-hydroxystyrene) 24 g was added to acetone 96
After dissolving in milliliter, t-butyl bromoacetate (9.7 g) and potassium carbonate (7.6 g) were added, and the mixture was reacted under reflux with stirring for 8 hours. Then, the reaction solution was extracted with ethyl acetate, washed with a 5% by weight aqueous acetic acid solution and water, and then ethyl acetate and the like were distilled off under reduced pressure, redissolved in acetone and added dropwise to water to obtain a polymer. Allowed to settle.
The polymer was dried overnight in a vacuum oven at 50 ° C. The obtained polymer has Mw of 12,000 and Mw / Mn of 1.
As a result of ¹³ C-NMR measurement, it was found that 23% of the hydrogen atoms of the phenolic hydroxyl group had a structure in which t-butoxycarbonylmethyl group was substituted. This polymer is referred to as polymer A-1.

Synthesis Example 2 300 g of poly (p-hydroxystyrene) was dissolved in 1,200 ml of tetrahydrofuran, 650 g of triethylamine was added, and 200 g of di-t-butyl dicarbonate was added at 0 ° C. with stirring to give 6 Reacted for hours. Then, the reaction solution was dropped into water to precipitate a polymer. The polymer was dried overnight in a vacuum dryer at 50 ° C. to obtain an acid dissociable group-containing polymer. The resulting polymer, Mw is 7,000, Mw / Mn is 1.7, ¹³ C
As a result of NMR measurement, it was found that 25% of the hydrogen atoms of the phenolic hydroxyl group had a structure in which t-butoxycarbonyl group was substituted. This polymer is referred to as polymer A-2.

Synthesis Example 3 20% by weight of p-hydroxystyrene, 65% by weight of p-ethylphenol and 15% by weight of other components contained as impurities (breakdown: water 10% by weight, p-cresol 4)
Wt%, 1 wt% phenol) 120g of a mixture of the composition
Was mixed with 17 g of t-butyl acrylate and 50 g of propylene glycol monomethyl ether to give a uniform solution. After bubbling this solution for 30 minutes, 2,2 '
-1.9 g of azobis (4-methoxy-2,4-dimethylvaleronitrile) was added, and while continuing the bubbling with nitrogen gas, the reaction temperature was maintained at 40 ° C and copolymerization was carried out for 7 hours. After the completion of the copolymerization, the reaction solution was mixed with a large amount of hexane to solidify the produced polymer. Then, after redissolving the polymer in acetone, hexane again,
The operation of solidifying was repeated several times to completely remove the unreacted monomer, and the solid was dried under reduced pressure at 50 ° C. to obtain a white polymer (yield 55%). The polymer obtained has an Mw of 3
1,000, Mw / Mn was 2.0, and as a result of ¹³ C-NMR measurement, the copolymerization molar ratio of p-hydroxystyrene and t-butyl acrylate was 60:40. This polymer is referred to as a polymer A-3.

Synthesis Example 4 67 g of p-isopropenylphenol and t-acrylic acid
After dissolving 64 g of butyl in 131 g of propylene glycol monomethyl ether, 8 g of azobisbutyronitrile was added, and the mixture was polymerized at 60 ° C. for 10 hours in a nitrogen atmosphere. After completion of the polymerization, the reaction solution was dropped into 5 liters of hexane to solidify the produced polymer. This polymer was redissolved in acetone, then dropped into a large amount of water and re-solidified to obtain 85 g of a white polymer. The obtained polymer had Mw of 12,400 and Mw / Mn of 1.8, ¹³
As a result of C-NMR measurement, the copolymerization molar ratio of p-isopropenylphenol and t-butyl acrylate was 49.5:
It was 50.5. This polymer is referred to as polymer A-4.

Synthesis Example 5 20% by weight of p-hydroxystyrene, 65% by weight of p-ethylphenol and 15% by weight of other components contained as impurities (breakdown: water 10% by weight, p-cresol 4)
Wt%, 1 wt% phenol) 120g of a mixture of the composition
Was mixed with 12.5 g of t-butoxystyrene and 50 g of propylene glycol monomethyl ether to give a uniform solution. After bubbling this solution for 30 minutes,
3.0 g of 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) was added, and the reaction temperature was kept at 40 ° C. for 7 hours for copolymerization while continuing the bubbling with nitrogen gas. After the polymerization was completed, the reaction solution was mixed with a large amount of hexane to solidify the produced polymer. Then
After re-dissolving the polymer in acetone, coagulation with hexane was repeated several times to completely remove the unreacted monomer, followed by drying under reduced pressure at 50 ° C. to give a white polymer (yield 55 %) Was obtained. The polymer obtained has an Mw of 1.
8,000, Mw / Mn was 1.9, and as a result of ¹³ C-NMR measurement, the copolymerization molar ratio of p-hydroxystyrene and t-butoxystyrene was 70:30. This polymer is referred to as polymer A-5.

Synthesis Example 6 White polymer 10 was prepared in the same manner as in Synthesis Example 4 except that 84 g of p-hydroxystyrene and 74.4 g of di (t-butyl) fumarate were dissolved in 150 ml of dioxane.
3 g were obtained. The obtained polymer has a Mw of 26,000,
Mw / Mn is 2.3, and the result of ¹³ C-NMR measurement is
The polymerization molar ratio of p-hydroxystyrene and di (t-butyl fumarate) was 69:31. This polymer is referred to as a polymer A-6.

Synthesis Example 7 20% by weight of p-hydroxystyrene, 65% by weight of p-ethylphenol and 15% by weight of other components contained as impurities (breakdown: water 10% by weight, p-cresol 4)
Wt%, 1 wt% phenol) 120g of a mixture of the composition
Was mixed with 13 g of t-butyl acrylate, 6.8 g of isobornyl acrylate and 50 g of propylene glycol monomethyl ether to give a uniform solution. This solution is
After bubbling for 0 minutes, 1.9 g of 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) was added, and while bubbling with nitrogen gas was continued, the reaction temperature was maintained at 40 ° C. Polymerized for hours. After polymerization,
The reaction solution was mixed with a large amount of hexane to solidify the produced polymer. Then, the polymer is redissolved in acetone and then coagulated again with hexane several times to completely remove the unreacted monomer and dried under reduced pressure at 50 ° C. to give a white polymer (collected). Rate 45%) was obtained. The obtained polymer has Mw of 28,000 and Mw / Mn of 1.4.
As a result of ¹³ C-NMR measurement, the copolymerization molar ratio of p-vinylphenol, t-butyl acrylate and isobornyl acrylate was 60:29:11. This polymer is referred to as a polymer A-7.

Synthesis of Polymer (B) Synthesis Example 8 Poly (p-hydroxystyrene) (Mw 12,000)
After 24 g was dissolved in 100 milliliter of dioxane, nitrogen was bubbled for 30 minutes. 8 g of ethyl vinyl ether and 1 g of p-toluenesulfonic acid pyridinium salt as a catalyst were added to this solution, and they were reacted for 12 hours. The reaction solution was added dropwise to a 1% by weight aqueous ammonia solution to precipitate a polymer. The polymer was dried overnight in a vacuum oven at 50 ° C. The polymer obtained has an Mw of 1.
2,000, Mw / Mn was 1.6, and as a result of ¹³ C-NMR measurement, 45% of hydrogen atoms of the phenolic hydroxyl group was 1
-An ethoxyethyl group-substituted structure. This polymer is referred to as a polymer B-1.

Synthesis Example 9 Poly (p-hydroxystyrene) (Mw 8,000) 2
After dissolving 4 g in 100 ml of dioxane,
Bubbled with nitrogen for 30 minutes. A few in this solution
-7.5 g of dihydropyran and 0.4 g of p-toluenesulfonic acid as a catalyst were added and reacted for 6 hours. The reaction solution was added dropwise to a 1% aqueous ammonia solution to precipitate the polymer. The polymer was dried overnight in a vacuum oven at 50 ° C. The obtained polymer has Mw of 10,000 and Mw
/ Mn was 1.8, and as a result of ¹³ C-NMR measurement, it had a structure in which 42% of the hydrogen atoms of the phenolic hydroxyl group were substituted with a tetrahydropyranyl group. This polymer is referred to as a polymer B-2.

Synthesis Example 10 Poly (p-hydroxystyrene) (Mw 24,000)
After 48 g was dissolved in 100 millilitre of dioxane, nitrogen was bubbled for 30 minutes. 7.5 g of 2,3-dihydropyran and 0.4 g of p-toluenesulfonic acid pyridinium salt as a catalyst were added to this solution, and the mixture was reacted for 6 hours. The reaction solution was added dropwise to a 1% aqueous ammonia solution to precipitate the polymer. The polymer was dried overnight in a vacuum oven at 50 ° C. The obtained polymer had Mw of 31,000 and Mw / Mn of 2.1, and ¹³ C-NMR
As a result of the measurement, it was found that 42% of the hydrogen atoms of the phenolic hydroxyl group had a structure in which a tetrahydropyranyl group was substituted. This polymer is referred to as a polymer B-3.

Synthesis Example 11 Poly (p-hydroxystyrene) (Mw 24,000)
After 48 g was dissolved in 100 millilitre of dioxane, nitrogen was bubbled for 30 minutes. 14 g of methyl vinyl ether and 0.4 g of p-toluenesulfonic acid pyridinium salt as a catalyst were added to this solution, and the reaction was carried out for 10 hours. The reaction solution was added dropwise to a 1% aqueous ammonia solution to precipitate the polymer. The polymer was dried overnight in a vacuum oven at 50 ° C. The polymer obtained has an Mw of 2
9000, Mw / Mn was 2.0, and as a result of ¹³ C-NMR measurement, it had a structure in which 53% of the hydrogen atoms of the phenolic hydroxyl group were substituted with a methoxymethyl group. This polymer is referred to as a polymer B-4.

Synthesis Example 12 20% by weight of p-hydroxystyrene, 65% by weight of p-ethylphenol and 15% by weight of other components contained as impurities (breakdown: water 10% by weight, p-cresol 4)
Wt%, 1 wt% phenol) 120g of a mixture of the composition
Was mixed with 19 g of tetrahydrofurfuryl acrylate and 50 g of dioxane to form a uniform solution. After bubbling this solution for 30 minutes, 2,2'-azobis (4
-Methoxy-2,4-dimethylvaleronitrile) 1.9 g
Was added, and while continuing the bubbling with nitrogen gas, the reaction temperature was maintained at 40 ° C. and copolymerization was carried out for 7 hours. After the polymerization was completed, the reaction solution was mixed with a large amount of hexane to solidify the produced polymer. Then, the polymer was redissolved in dioxane, and the procedure of coagulating again with hexane was repeated several times to completely remove the unreacted monomer.
After drying under reduced pressure at ℃, a white polymer (yield 52%) was obtained. The obtained polymer has Mw of 27,000 and Mw / M.
n was 2.1, and as a result of ¹³ C-NMR measurement, the copolymerization molar ratio of p-hydroxystyrene and tetrahydrofurfuryl acrylate was 62:38. This polymer is referred to as a polymer B-5.

Synthesis Example 13 Poly (p-hydroxystyrene) (Mw 12,000)
After 24 g was dissolved in 100 milliliter of dioxane, nitrogen was bubbled for 30 minutes. 4
15 g of -methoxy-5,6-dihydro-2H-pyran and 0.5 g of p-toluenesulfonic acid pyridinium salt as a catalyst were added and reacted for 12 hours. The reaction solution was added dropwise to a 1% by weight aqueous ammonia solution to precipitate a polymer. The polymer was dried overnight in a vacuum oven at 50 ° C. The obtained polymer has Mw of 15,000 and Mw
/ Mn is 1.8, and as a result of ¹³ C-NMR measurement, it has a structure in which 40% of the hydrogen atoms of the phenolic hydroxyl group are substituted with a methoxytetrahydropyranyl group,
From 13 C-NMR, 7% had a cyclohexanol structure. This polymer is referred to as a polymer B-6.

Synthesis Example 14 Poly (p-hydroxystyrene) (Mw 12,000)
After 24 g was dissolved in 100 milliliter of dioxane, nitrogen was bubbled for 30 minutes. 1 in this solution
-Methoxycyclohexene 12 g and p-toluenesulfonic acid pyridinium salt 0.7 g as a catalyst were added, and 24
Allowed to react for hours. The reaction solution was added dropwise to a 1% aqueous ammonia solution to precipitate the polymer. This polymer at 50 ° C
Overnight in a vacuum oven. The polymer obtained is M
w is 14,000, Mw / Mn is 2.0, and ¹³ C-N
As a result of the MR measurement, the number of hydrogen atoms of the phenolic hydroxyl group was 40
% Had a structure in which 1-methoxycyclohexyl group was substituted. This polymer is referred to as a polymer B-7.

Synthesis Example 15 Poly (p-hydroxystyrene) (Mw 12,000)
After 24 g was dissolved in 100 milliliter of dioxane, nitrogen was bubbled for 30 minutes. 2 in this solution
-Methoxypropylene 8 g and p-toluenesulfonic acid pyridinium salt 0.9 g as a catalyst were added and reacted for 18 hours. The reaction solution was added dropwise to a 1% aqueous ammonia solution to precipitate the polymer. The polymer was dried overnight in a vacuum oven at 50 ° C. The polymer obtained has an Mw of 1.
5,000, Mw / Mn was 1.8, and as a result of ¹³ C-NMR measurement, it was found that 59% of the hydrogen atoms of the phenolic hydroxyl group had a structure in which a methoxypropyl group was substituted. This polymer is referred to as a polymer B-8.

Examples 1 to 15 The respective components shown in Table 1 (however, parts are based on weight) were mixed to form a uniform solution, which was then filtered through a membrane filter having a pore size of 0.2 μm to give a composition solution. Prepared. After that, each composition solution was spin-coated on a silicon wafer, and then prebaked at 90 ° C. for 120 seconds to form a resist film having a film thickness of 1.0 μm. Then, exposure under the conditions shown in Table 2 (Stepper NSR-2005 E manufactured by Nikon Corporation in the case of exposure with KrF excimer laser)
When using X8A and electron beam exposure, acceleration voltage is 50K
V, current density 10 A / cm ² , variable shaped beam (HL-
800D)) and post-exposure bake,
Using a 2.38 wt% tetramethylammonium hydroxide aqueous solution, alkali development was performed by a dipping method at 23 ° C. for 1 minute, followed by washing with pure water and drying to form a resist pattern. Table 2 shows the evaluation results of each resist.

[0116]

[Table 1]

[0117]

[Table 2]

Here, the radiation-sensitive acid generator, the acid diffusion controller and the solvent in each Example and Comparative Example are as follows. Radiation-sensitive acid generator (acid generator) a): triphenylsulfonium triflate b): N- (camphanylsulfonyloxy) naphthyldicarboximide c): pyrogallol methanesulfonic acid triester d): N- (tri Fluoromethylsulfonyloxy) bicyclo- [2.2.1] hept-5-ene-2,3-dicarboximidopho): bis (cyclohexylsulfonyl) diazomethane
Acid diffusion control agent f): Nicotinic acid amide): Trioctylamine solvent EL: Methyl lactate MMP: Methyl 3-methoxypropionate PGMEA: Propylene glycol monomethyl ether acetate

[0119]

INDUSTRIAL APPLICABILITY The radiation-sensitive composition of the present invention is particularly excellent in resolution and pattern shape, excellent in PED stability, small in baking temperature dependency, excellent in process stability, and highly precise fine pattern. Can be stably formed. Moreover, the radiation-sensitive composition of the present invention,
It is effectively sensitive to various radiations such as ultraviolet rays, far ultraviolet rays, X-rays and valence electrons, and is extremely useful as a chemically amplified positive resist. Therefore, the radiation-sensitive composition of the present invention can be suitably used for manufacturing semiconductor devices, which are expected to be further miniaturized in the future.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kiji Yukimoto 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside Nippon Gosei Rubber Co., Ltd.

Claims (1)

[Claims] 1. A polymer having a substituent having a t-butyl group which can be decomposed by an acid (A), a polymer having an acetal group or a ketal group which can be decomposed by an acid (B), and (C) a radiation-sensitive polymer. A radiation-sensitive composition containing an acid generator.