JP2003295443A - Resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition excellent in transmittance to light of ≤170 nm wavelength and suitable particularly for F<SB>2</SB>excimer laser lithography. <P>SOLUTION: The resist composition comprises a resin and an acid generator, wherein the resin undergoes a chemical change and becomes alkali-soluble by the action of the acid generator after irradiation with a radiation and contains a polymerized unit represented by formula (I') and a polymerized unit represented by formula (I). In the formula (I'), R<SP>1</SP>-R<SP>4</SP>are each independently a 1-12C fluoroalkyl having at least one F atom and R<SP>5</SP>is H, halogen, cyano, a 1-3C alkyl or a 1-12C fluoroalkyl having at least one F atom. In the formula (I), R<SP>1</SP>-R<SP>4</SP>have the same meanings as the above R<SP>1</SP>-R<SP>4</SP>and R<SP>a</SP>and R<SP>b</SP>are each independently a group which is cleaved by an acid or H but at least one of R<SP>a</SP>and R<SP>b</SP>is a group which is cleaved by an acid. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resist composition used for fine processing of semiconductors.

[0002]

2. Description of the Related Art A lithography process using a resist composition is usually employed for fine processing of semiconductors. In lithography, Rayleigh is used.
As represented by the diffraction limit formula of gh), in principle, the shorter the exposure wavelength, the higher the resolution can be. The exposure light source for lithography used for manufacturing semiconductors is a g-line with a wavelength of 436 nm, an i-line with a wavelength of 365 nm, and a wavelength of 24
8nm KrF excimer laser, wavelength 193nm A
With the rF excimer laser, the wavelength has become shorter each year,
Further, as a next-generation exposure light source, an F ₂ excimer laser with a wavelength of 157 nm is considered promising. For KrF excimer laser exposure and ArF excimer laser exposure, so-called chemically amplified resists that utilize the catalytic action of acid generated by exposure are often used because of their excellent sensitivity. Also, for the F ₂ excimer laser exposure, there is a high possibility that the chemically amplified resist is used in terms of sensitivity.

Polyvinylphenol resins have been used as resists for KrF excimer laser exposure. On the other hand, the resin used for the resist for ArF excimer laser exposure does not have an aromatic ring in order to secure the transmittance of the resist, and has an alicyclic ring in place of the aromatic ring in order to have dry etching resistance. It is known that things are good.

However, the resin used in the conventional resist for KrF excimer laser exposure or ArF excimer laser exposure is sufficiently transmissive to light having a wavelength of 170 nm or less, for example, F ₂ excimer laser having a wavelength of 157 nm. No rate was shown. A low transmittance adversely affects various performances such as profile, contrast and sensitivity.

Further, German Patent No. 4207261
In the specification, a polymer containing the following polymerized units (VI) is
Considered as a positive resist. (Q¹Is the number of carbon atoms that may be substituted with a hydrogen atom or halogen
1-4 alkyl groups, Q ²~ Q^FiveAre independent hydrogen
Child or halogen atom or charcoal optionally substituted with halogen
It may be substituted with an aliphatic group having a prime number of 1 to 20 or halogen.
Substituted with an aromatic group having 6 to 14 carbon atoms or halogen
Aralkyl group having 7 to 20 carbon atoms, Q ⁶Is an acid cleavage group
Represents)

[0006]

The object of the present invention is to
Excellent transmittance for light with a wavelength of 0 nm or less, especially F ₂
It is to provide a resist composition suitable for excimer laser lithography.

[0007]

The inventors of the present invention have used a resin having a polymerized unit derived from a specific monomer as a resin constituting a resist composition so that the balance of performance and the F ₂ excimer laser of 157 nm can be obtained. The present invention has been completed by finding that the transmittance at the wavelength of can be improved.

That is, the present invention comprises a resin and an acid generator, and the resin undergoes a chemical change by the action of the acid generator after irradiation to become alkali-soluble and has the following formula (I The present invention relates to a resist composition containing a polymerized unit represented by '). (In the formula, R ¹ , R ² , R ³ , and R ⁴ each independently represent a fluoroalkyl group having at least one fluorine atom and having 1 to 12 carbon atoms, and R ⁵ is a hydrogen atom, a halogen atom, It represents a cyano group, an alkyl group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 12 carbon atoms and having at least one fluorine atom.)

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the radiation-exposed portion of the resist film is removed by alkali development to form a positive resist. That is, in the chemically amplified positive resist, the acid or base generated from the acid generator in the irradiation part is diffused by the subsequent heat treatment (post exposure bake) to cleave the protective group such as the resin and the acid or base. Is regenerated to make the irradiated portion soluble in the alkaline aqueous solution.

In the resist composition of the present invention, a resin having a polymerized unit represented by the above formula (I ') is used as the resin. The resin in the present invention may be referred to as a binder resin. It is preferable that R ¹ , R ² , R ³ and R ^{4 in the} above formula (I ′) are all trifluoromethyl groups.

By incorporating the polymerized unit of the formula (I ') into the binder resin, the resin has excellent transmittance for light having a wavelength of 170 nm or less, for example, F ₂ excimer laser having a wavelength of 157 nm. In the resin of the present invention, an arbitrary ratio can be selected as the ratio containing the polymerized unit represented by the formula (I ′), but the resin itself is insoluble or hardly soluble in an alkali developing solution, It may be selected within a range in which it is soluble in the alkaline aqueous solution by the action of the acid generator after irradiation.

Examples of the resist composition of the present invention include compositions in which the resin contains a resin containing a polymerized unit represented by the above formula (I ') and a polymerized unit represented by the following formula (I). (In the formula, R ¹ , R ² , R ³ and R ⁴ are each independently and independently of those in the formula (I ′), a fluoroalkyl group having 1 to 12 carbon atoms and having at least one fluorine atom. the stands, R ⁵ is a hydrogen atom, a halogen atom, a cyano group,
It represents an alkyl group having 1 to 3 carbon atoms or a fluoroalkyl group having 1 to 12 carbon atoms having at least one fluorine atom. R ^a and R ^b each independently represent a group that is cleaved by an acid or a hydrogen atom. However, at least one of R ^a and R ^b represents a group that is cleaved by an acid. ) R ^a , R ^b
Is preferably a group that is cleaved by an acid.
When R ^a and R ^b in the formula (I) are groups capable of being cleaved by an acid, a group capable of inhibiting dissolution in an alkali developing solution is used. The above-mentioned resin having a group capable of being cleaved by an acid can be preferably applied as a positive resist using an acid generator.

The group cleaved by the acid is, for example,
tert-butyl group, tert-butoxycarbonyl group or tert
A group in which a quaternary carbon is bonded to an oxygen atom, such as butoxycarbonylmethyl group; tetrahydro-2-pyranyl group, tetrahydro-2-furyl group, methoxymethyl group, ethoxymethyl group, 1-adamantyloxymethyl group, t- Butoxymethyl group, i-propoxymethyl group, 1-ethoxyethyl group, 1- (2-methylpropoxy) ethyl group,
2-methoxyethoxymethyl group, 1- (2-methoxyethoxy) ethyl group, 1- (2-acetoxyethoxy) ethyl group, 1- [2- (1-adamantyloxy) ethoxy] ethyl group or 1- [2- Acetal-type groups such as (1-adamantanecarbonyloxy) ethoxy] ethyl group; 3-oxocyclohexyl group, 4-methyltetrahydro-2-pyron-4-yl group (derived from mevalonic lactone), 1- Examples thereof include a non-aromatic cyclic compound group such as an adamantyl-1-alkylalkyl group or a 2-alkyl-2-adamantyl group. These groups may be collectively referred to as an acid-cleaving group group A.

Further, as the resist composition of the present invention,
Examples thereof include a composition containing a resin containing a polymerized unit represented by the formula (I ′) and a polymerized unit represented by the following formula (II). (In the formula, R ⁶ represents a group that is cleaved by the action of an acid, and R ⁷ represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 3 carbon atoms, or a carbon number having at least one fluorine atom. It represents a fluoroalkyl group of 1 to 3.)

In the formula (II), R ⁶ includes the acid cleavage group A described above, preferably 2-alkyl-
A 2-adamantyl group may be mentioned.

In formula (II), R ⁷ is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.

Further, as the composition of the present invention, a resin is
A resin containing a polymerized unit represented by the formula (I ′) and a polymerized unit represented by the following formula (III), or a polymerized unit represented by the formula (I ′) and a polymerized unit represented by the formula (I) and formula
(III) a resin containing a polymerized unit, or a resin containing a polymerized unit represented by the formula (I ′), a polymerized unit represented by the formula (II) and a polymerized unit represented by the following formula (III) Certain compositions are included. (In the formula, R ⁸ represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 3 carbon atoms and having at least one fluorine atom.)

Formula (I '), Formula (I), Formula (II),
Some typical examples of the binder resin in which any of the polymerized units represented by the formula (III) is incorporated and undergoes a chemical change by the action of the acid generator after irradiation to become soluble in an alkaline aqueous solution will be given. And a resin having a polymerized unit as shown below.

Resin (a) having the following polymerized units

Resin (b) having the following polymerized units

Resin (c) having the following polymerized units

Resin (d) having the following polymerized units

Resin (e) having the following polymerized units

Resin (f) having the following polymerized units

Resin (g) having the following polymerized units

Resin (h) having the following polymerized units

Resin (i) having the following polymerized units

Resin (j) having the following polymerized units

Resin (k) having the following polymerized units

Resin (l) having the following polymerized units

Resin (m) having the following polymerized units

Resin (n) having the following polymerized units

Resin (o) having the following polymerized units

Resin (p) having the following polymerized units

The resin used in the present invention can be used as a mixture with another binder resin. Examples of the binder resin include a fluorine-containing norbornene polymer having a polymerized unit represented by the following formula (IV). (In the formula, R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 14 carbon atoms, an alicyclic ring or a lactone ring.
It may be substituted with a halogen atom, a hydroxyl group or an alicyclic ring. The alicyclic ring and lactone ring which are R ⁹ , R ¹⁰ or R ¹¹ may be independently substituted with a halogen atom, a hydroxyl group or an alkyl group. R ^c represents a group that is cleaved by an acid. )

Examples of R ^C in the formula (IV) include the groups of the aforementioned acid cleaving group A group.

As another binder resin which can be mixed and used, a polymer having fluorine in the main chain represented by the following formula (V) is also mentioned. (In the formula, n represents an integer of 0 to 1. R ^d represents a group that is cleaved by an acid.)

Examples of R ^d in the formula (V) include the groups of the above-mentioned acid cleaving group A group.

The resist composition of the present invention contains the above-mentioned alkali-soluble resin as a binder resin and further contains an acid generator which is decomposed by the action of radiation. Examples of the acid generator include various compounds that generate an acid by irradiating the substance itself or a resist composition containing the substance with radiation. Examples thereof include onium salts, halogenated alkyltriazine compounds, disulfone compounds, compounds having a diazomethanesulfonyl skeleton, and sulfonate compounds. Specific examples of such an acid generator are shown below.

Onium salts: diphenyliodonium trifluoromethanesulfonate, 4-methoxyphenylphenyliodonium hexafluoroantimonate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium tetrafluoroborate, bis (4 -Tert-butylphenyl) iodonium hexafluorophosphate, bis (4-tert-butylphenyl) iodonium hexafluoroantimonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyliodonium camphor Sulfonate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroan Zimonate,
Triphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium hexafluoroantimonate, 4-methoxyphenyldiphenylsulfonium trifluoromethanesulfonate, p-tolyldiphenylsulfonium trifluoromethanesulfonate, 2,4,6-trimethylphenyldiphenylsulfonium trifluoromethanesulfonate , 4-tert-butylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-phenylthiophenyldiphenylsulfonium hexafluorophosphate, 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, 1-
(2-naphthoylmethyl) thioranium hexafluoroantimonate, 1- (2-naphthoylmethyl) thioranium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium hexafluoroantimonate, 4-hydroxy-1-naphthyldimethylsulfonium Trifluoromethane sulfonate etc.

Halogenated alkyltriazine compounds:
2-methyl-4,6-bis (trichloromethyl) -1,
3,5-triazine, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-
4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-chlorophenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4
-Methoxyphenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxy-
1-naphthyl) -4,6-bis (trichloromethyl)-
1,3,5-triazine, 2- (benzo [d] [1,
3] Dioxolan-5-yl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxystyryl) -4,6-bis (trichloromethyl)-
1,3,5-triazine, 2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl)-
1,3,5-triazine, 2- (3,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,
3,5-triazine, 2- (2,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5
-Triazine, 2- (2-methoxystyryl) -4,6
-Bis (trichloromethyl) -1,3,5-triazine,
2- (4-butoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-pentyloxystyryl) -4,6-bis (trichloromethyl) -1,3 , 5-triazine and the like.

Disulfone compounds: diphenyl disulfone, di-p-tolyl disulfone, phenyl p-tolyl disulfone, phenyl p-methoxyphenyl
Such as disulfone.

Compounds having a diazomethanesulfonyl skeleton: bis (phenylsulfonyl) diazomethane, bis (4-chlorophenylsulfonyl) diazomethane, bis (p-tolylsulfonyl) diazomethane, bis (4-te)
rt-Butylphenylsulfonyl) diazomethane, bis (2,4-xylylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane, (benzoyl) (phenylsulfonyl) diazomethane and the like.

Sulfonate compounds: 1-benzoyl-1-phenylmethyl p-toluenesulfonate (commonly called benzointosylate), 2-benzoyl-2-
Hydroxy-2-phenylethyl p-toluenesulfonate (commonly known as α-methylolbenzointosylate),
1,2,3-benzenetriyl trismethane sulfonate, 2,6-dinitrobenzyl p-toluene sulfonate, 2-nitrobenzyl p-toluene sulfonate, 4-nitrobenzyl p-toluene sulfonate,
N- (phenylsulfonyloxy) succinimide, N
-(P-tolylsulfonyloxy) succinimide, N
-(Trifluoromethylsulfonyloxy) succinimide, N- (isopropylsulfonyloxy) succinimide N- (n-butylsulfonyloxy) succinimide, N- (n-hexylsulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) succinimide , N- (trifluoromethylsulfonyloxy) phthalimide, N- (trifluoromethylsulfonyloxy) -5-norbornene-2,3-dicarboximide, N- (trifluoromethylsulfonyloxy) naphthalimide, N- (10 -Camphorsulfonyloxy) naphthalimide and the like.

In the composition of the present invention, by adding an organic base compound, particularly a nitrogen-containing basic organic compound, it is possible to improve the performance deterioration due to the deactivation of the acid accompanying the storage after exposure. The organic base compound may be hereinafter referred to as a quencher. Specific examples of such a nitrogen-containing basic organic compound include amines represented by the following formulas.

[0046]

In the formula, R ¹² , R ¹³ and R ¹⁸ each independently represent hydrogen, alkyl, cycloalkyl or aryl. The alkyl, cycloalkyl or aryl may be each independently substituted with a hydroxyl group, an amino group or an alkoxy group having 1 to 6 carbon atoms. The amino group is
It may be substituted with an alkyl group having 1 to 4 carbon atoms. The alkyl preferably has about 1 to 6 carbon atoms, the cycloalkyl preferably has about 5 to 10 carbon atoms, and the aryl preferably has about 6 to 10 carbon atoms. R ¹⁴ , R ¹⁵
And R ¹⁶ each independently represent hydrogen, alkyl, cycloalkyl, aryl or alkoxy. The alkyl, cycloalkyl, aryl or alkoxy may be each independently substituted with a hydroxyl group, an amino group or an alkoxy group having 1 to 6 carbon atoms. The amino group may be substituted with an alkyl group having 1 to 4 carbon atoms. The alkyl preferably has about 1 to 6 carbon atoms, the cycloalkyl preferably has about 5 to 10 carbon atoms, the aryl preferably has about 6 to 10 carbon atoms, and the alkoxy has 1 to 6 carbon atoms. About 6 is preferable. R ¹⁷ is
Represents alkyl or cycloalkyl. The alkyl or cycloalkyl each independently represents a hydroxyl group, an amino group,
It may be substituted with an alkoxy group having 1 to 6 carbon atoms. The amino group may be substituted with an alkyl group having 1 to 4 carbon atoms. The alkyl preferably has about 1 to 6 carbon atoms, and the cycloalkyl preferably has about 5 to 10 carbon atoms. A represents alkylene, carbonyl, imino, sulfide or disulfide. The alkylene preferably has about 2 to 6 carbon atoms. Also, R
Any of ^{12 to} R ¹⁸ may have both a linear structure and a branched structure.

Specific examples of such a compound include hexylamine, heptylamine, octylamine, nonylamine, decylamine, aniline, 2-, 3- or 4
-Methylaniline, 4-nitroaniline, 1- or 2-
Naphthylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-
3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, N-methylaniline, piperidine, Diphenylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine,
Methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldiethyl Nonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2
-(2-Methoxyethoxy) ethyl] amine, triisopropanolamine, N, N-dimethylaniline, 2,
6-isopropylaniline, imidazole, pyridine,
4-methylpyridine, 4-methylimidazole, bipyridine, 2,2'-dipyridylamine, di-2-pyridylketone, 1,2-di (2-pyridyl) ethane, 1,2-
Di (4-pyridyl) ethane, 1,3-di (4-pyridyl) propane, 1,2-bis (2-pyridyl) ethylene, 1,2-bis (4-pyridyl) ethylene, 1,2-
Bis (4-pyridyloxy) ethane, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide,
1,2-bis (4-pyridyl) ethylene, 2,2'-dipicolylamine, 3,3'-dipicolylamine, tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetra- n-hexyl ammonium hydroxide, tetra-n-octyl ammonium hydroxide, phenyltrimethyl ammonium hydroxide,
3- (trifluoromethyl) phenyl trimethyl ammonium hydroxide, choline, etc. can be mentioned.

Further, a hindered amine compound having a piperidine skeleton as disclosed in JP-A No. 11-52575 can be used.

The resist composition of the present invention may contain the resin in an amount of 60 to 99.9% by weight and the acid generator in an amount of 40 to 0.1% by weight based on the total weight of the resin and the acid generator. It is more preferable to contain the binder resin in the range of 80 to 99.9% by weight and the acid generator in the range of 20 to 0.1% by weight.

When a basic compound is used in the composition of the present invention, it is preferably contained in an amount of about 0.01 to 1 part by weight based on 100 parts by weight of the binder resin. Further, the composition of the present invention, if necessary,
A small amount of various additives such as sensitizers, other resins, surfactants, stabilizers and dyes may be contained.

The resist composition of the present invention usually becomes a liquid resist composition in a state where each of the above components is dissolved in a solvent and is applied onto a substrate such as a silicon wafer by a conventional method such as spin coating. . The solvent used here may be any solvent that dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after the solvent evaporates. Solvents generally used in this field are used. You can.

For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate or propylene glycol monomethyl ether acetate; ethers such as diethylene glycol dimethyl ether; esters such as ethyl lactate, butyl acetate, amyl acetate or ethyl pyruvate. Ketones such as acetone, methyl isobutyl ketone, 2-heptanone or cyclohexanone; or γ
-Cyclic esters such as butyrolactone may be mentioned. These solvents may be used alone or in combination of two or more.

The resist film coated and dried on the substrate is subjected to an exposure treatment for patterning, and then a heat treatment for accelerating a deprotecting group reaction or a crosslinking reaction, followed by an alkali developing solution. To be developed. The alkaline developer used here can be various alkaline aqueous solutions used in this field, but in general, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline) is used. Often used. In the above,
Although the embodiments of the present invention have been described, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the invention is indicated by the claims,
Further, the meaning equivalent to the description of the claims and all modifications within the scope are included.

[0055]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Parts in the examples are by weight unless otherwise specified. The weight average molecular weight is a value determined by gel permeation chromatography using polystyrene as a standard product.

(1a) Synthesis of 3,5-bis (2-hydroxyhexafluoroisopropyl) styrene polymer 50 equipped with magnetic stirrer, cooling tube, thermometer, nitrogen introducing tube
A 2-mL 3-necked flask was charged with 2.25 g of 3,5-bis (2-hydroxyhexafluoroisopropyl) styrene and 2.25 g of methyl isobutyl ketone, heated to 75 ° C., and 0.025 g of azobisisobutyronitrile. 2.
A solution dissolved in 25 g of methyl isobutyl ketone was added. After that, it is kept warm for 10 hours, cooled to room temperature, and then N-
The reaction solution was poured into 67.5 g of heptane, and the precipitated resin was taken out by decantation. The amount of the resin obtained was 1.45 g and its weight average molecular weight was 1090.
1, the dispersion was 1.7. This resin is designated as A.

(1b) Synthesis of partially ethoxymethylated 3,5-bis (2-hydroxyhexafluoroisopropyl) styrene polymer 50 equipped with a magnetic stirrer, cooling tube, thermometer, nitrogen introducing tube
In a mL three-necked flask, 0.8 g of Resin A, 8.0 g of methyl isobutyl ketone, and 0.9 g of diisopropylethylamine.
Charge 33 g and add ethoxymethyl chloride to 0.12
g was added. After stirring at room temperature for 4 hours, methyl isobutyl ketone was added, and the oil layer was washed 8 times with ion-exchanged water. The obtained oil layer was concentrated, poured into normal heptane, and the precipitated resin was taken out by decantation. Then, it was dried under reduced pressure to obtain a resin. The amount of resin obtained is 0.77.
The weight average molecular weight was 11805, and the dispersion was 1.6. Moreover, ethoxymethylation was 29% with respect to all the hydroxyl groups. This resin is designated as B.

(2a) A resin was obtained in the same manner as the synthetic resin A of 3,5-bis (2-hydroxyhexafluoroisopropyl) styrene polymer. The amount of the obtained resin was 1.56 g, the weight average molecular weight was 9798, and the dispersion was 1.7. This resin is designated as C.

(2b) Synthesis of partially ethoxymethylated 3,5-bis (2-hydroxyhexafluoroisopropyl) styrene polymer 50 equipped with a magnetic stirrer, cooling tube, thermometer, nitrogen introducing tube
In a mL three-necked flask, 0.8 g of Resin A, 8.0 g of methyl isobutyl ketone, and 0.6 g of diisopropylethylamine.
Charge 6g, 0.18g ethoxymethyl chloride
added. After stirring at room temperature for 3 hours, 0.03 g of ethoxymethyl chloride was further added, and the mixture was stirred for 2 hours. afterwards,
Methyl isobutyl ketone was added, and the oil layer was washed 8 times with ion-exchanged water. The obtained oil layer was concentrated, poured into normal heptane, and the precipitated resin was taken out by decantation. Then, it was dried under reduced pressure to obtain a resin. The amount of resin obtained is 0.34 g and the ethoxymethylation is
It was 45% based on all hydroxyl groups. This resin is designated as D.

Example 1 Next, in addition to the resin B obtained as in Synthesis Example, a resist composition was prepared using the following acid generator and quencher, and the transmittance was measured. The resist was prepared by mixing and dissolving the following components and further filtering with a fluororesin filter having a pore size of 0.2 μm.

[0061] Resin B: 10 parts Acid generator: p-tolyldiphenylsulfonium perfluorooctanesulfone 0.2 parts Quencher: Tetrabutylammonium hydroxide 0.0075 parts solvent:   Propylene glycol monomethyl ether acetate 95 parts   γ-butyrolactone 5 parts

On the other hand, on the magnesium fluoride wafer, the film thickness after drying the resist solution prepared as described above is 0.
It was applied to have a thickness of 1 μm and prebaked on a direct hot plate under the conditions of 110 ° C. for 60 seconds to form a resist film. The transmittance of the resist film thus formed at a wavelength of 157 nm was measured using a vacuum ultraviolet spectrophotometer (manufactured by JASCO Corporation).
%Met.

A resin film was formed not only on the resist composition but also on the solution in which only the resin A was dissolved in a solvent, and the transmittance at 157 nm was measured by a vacuum ultraviolet spectrophotometer (manufactured by JASCO Corporation). When measured using 65
%Met.

Comparative Example 1 A resin film was formed on a solution prepared by synthesizing a 4- (2-hydroxyhexafluoroisopropyl) styrene polymer and dissolving it in a solvent, and the transmittance at 157 nm was calculated as follows.
It was 46% when measured using a vacuum ultraviolet spectrophotometer (manufactured by JASCO Corporation).

[0065]

The resist composition of the present invention has a thickness of 170 nm.
In the exposure using a light source having the following wavelength, for example, a F ₂ excimer laser having a wavelength of 157 nm, a high transmittance is exhibited,
Excellent performance can be exhibited as a resist composition using a light source having a wavelength of 170 nm or less.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08F 236/20 C08F 236/20 H01L 21/027 H01L 21/30 502R (72) Inventor Yoshiharu Toishi Kasuga, Konohana-ku, Osaka Idemaka 3-chome 1-98 Sumitomo Chemical Co., Ltd. F-term (reference) 2H025 AA02 AA03 AB16 AC04 AD03 BE00 BE10 BG00 CB08 CB14 CB16 CB41 CB45 CC20 FA17 4J100 AB07P AB10P AL03Q AL08Q AL29Q AM02Q AM02R AR11P0302 BA02S02B02S02B02S BB07T BB18P BB18Q BB18S BB18T BC09Q CA01 CA03 CA04 CA05 CA06 JA38

Claims (14)

[Claims] 1. A resin containing an acid generator and the resin which undergoes a chemical change by the action of the acid generator after irradiation to become alkali-soluble and is represented by the following formula (I ′): A resist composition comprising a polymerized unit as described above. (In the formula, R ¹ , R ² , R ³ , and R ⁴ each independently represent a fluoroalkyl group having at least one fluorine atom and having 1 to 12 carbon atoms, and R ⁵ is a hydrogen atom, a halogen atom, It represents a cyano group, an alkyl group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 12 carbon atoms and having at least one fluorine atom.) 2. R ¹ , R ² , R ³ and R ^{4 in the} formula (I ′) are
The composition according to claim 1, wherein both are trifluoromethyl groups. 3. The composition according to claim 1, wherein the resin is a resin containing a polymerized unit represented by the formula (I ′) and a polymerized unit represented by the following formula (I). (In the formula, R ¹ , R ² , R ³ and R ⁴ are each independently and independently of those in the formula (I ′), a fluoroalkyl group having 1 to 12 carbon atoms and having at least one fluorine atom. the stands, R ⁵ is a hydrogen atom, a halogen atom, a cyano group,
It represents an alkyl group having 1 to 3 carbon atoms or a fluoroalkyl group having 1 to 12 carbon atoms having at least one fluorine atom. R ^a and R ^b each independently represent a group that is cleaved by an acid or a hydrogen atom. However, at least one of R ^a and R ^b represents a group that is cleaved by an acid. ) 4. The composition according to claim 3, wherein R ^a and R ^b in the formula (I) are both groups capable of being cleaved by an acid. 5. The composition according to claim 1, wherein the resin contains a polymerized unit represented by the formula (I ′) and a polymerized unit represented by the following formula (II). (In the formula, R ⁶ represents a group that is cleaved by the action of an acid, and R ⁷ represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 3 carbon atoms, or a carbon number having at least one fluorine atom. It represents a fluoroalkyl group of 1 to 3.) 6. The composition according to claim 5, wherein in the formula (II), R ⁶ is a 2-alkyl-2-adamantyl group. 7. A compound represented by the formula (II) wherein R ⁷ is a hydrogen atom, a methyl group or a trifluoromethyl group.
Or the composition according to 6. 8. A resin containing a polymerized unit represented by the formula (I ′) and a polymerized unit represented by the following formula (III), or a polymerized unit represented by the formula (I ′) and a formula (I) ) And a polymer unit having a polymer unit represented by the following formula (III), or a polymer unit represented by the formula (I ′) and a polymer unit represented by the formula (II) and the following formula (III) The composition according to any one of claims 1 to 7, which is a resin containing the polymerized unit shown. (In the formula, R ⁸ represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 3 carbon atoms, or a fluoroalkyl group having 1 to 3 carbon atoms and having at least one fluorine atom.) 9. The composition according to claim 1, further comprising a resin containing a polymerized unit represented by the following formula (IV). (In the formula, R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 14 carbon atoms, an alicyclic ring or a lactone ring.
It may be substituted with a halogen atom, a hydroxyl group or an alicyclic ring. The alicyclic ring and lactone ring which are R ⁹ , R ¹⁰ or R ¹¹ may be independently substituted with a halogen atom, a hydroxyl group or an alkyl group. R ^c represents a group that is cleaved by an acid. ) 10. The composition according to claim 1, further comprising a resin containing a polymerized unit represented by the following formula (V). (In the formula, n represents an integer of 0 to 1. R ^d represents a group that is cleaved by an acid.) 11. The acid generator is an active compound which generates an acid by the action of radiation, and acts positively.
11. The composition according to any one of 10. 12. The resin according to claim 1, which contains 60 to 99.9% by weight of the resin and 40 to 0.1% by weight of the acid generator based on the total weight of the resin and the acid generator. The composition according to claim 1. 13. The composition according to claim 1, which further comprises a basic compound. 14. The basic compound is in the range of 0.001 to 1 part by weight based on 100 parts by weight of the resin.
The composition as described.