JPH1055069A - Radiation sensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve transparency to far UV and to increase adhesive strength to a substrate by incorporating a resin having a specified group as at least one terminal group of its molecular chain and having solubility to an alkali developer increased by the action of an acid and a radiation sensitive acid generating agent. SOLUTION: This radiation sensitive resin compsn. contains a resin having a group represented by the formula -X-COOH as at least one terminal group of its molecular chain and having solubility to an alkali developer increased by the action of an acid and a radiation sensitive acid generating agent. In the formula, X is a divalent group represented by -R<1> -, -S-R<1> -, -NH-R<1> - or -O-R<1> and R<1> is 1-20C divalent hydrocarbon which may have a substituent. The resin is, e.g., a resin having the terminal group and a group forming an acidic functional group such as a carboxyl or phenolic hydroxyl group when dissociated by the action of an acid generated, e.g. by exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-sensitive resin composition and, more particularly, to a chemically amplified resist useful particularly for fine processing using far ultraviolet rays such as a KrF excimer laser or an ArF excimer laser. The present invention relates to a radiation-sensitive resin composition that can be used.

[0002]

2. Description of the Related Art In the field of microfabrication represented by the manufacture of integrated circuit elements, recently, in order to obtain a higher degree of integration, a sub-half micron order (0.4 μm or less) has been used.
The development of lithography technology that enables microfabrication of silicon has been promoted, and it is said that in the near future, a microfabrication technology of a sub-quarter micron (0.20 μm or less) level will be required. In order to enable sub-quarter micron level microfabrication, the use of radiation having a shorter wavelength is being studied. Examples of such short-wavelength radiation include the emission line spectrum of a mercury lamp, deep ultraviolet rays represented by an excimer laser, X-rays, and electron beams. Of these, a KrF excimer laser or an ArF excimer is particularly preferable. Lasers are attracting attention.
Such a radiation-sensitive resin composition suitable for irradiation with an excimer laser includes a component having an acid-dissociable functional group and a radiation-sensitive acid generator that generates an acid upon irradiation with radiation (hereinafter, referred to as “exposure”). (Hereinafter referred to as "chemically amplified radiation-sensitive composition").
Many have been proposed. As such a chemically amplified radiation-sensitive composition, for example, Japanese Patent Publication No. 2-27660 discloses a polymer having a t-butyl ester group of carboxylic acid or a t-butyl carbonate group of phenol and a radiation-sensitive composition. Compositions containing an acid generator have been proposed. In this composition, the t-butyl ester group or t-butyl carbonate group present in the polymer is dissociated by the action of an acid generated by exposure, and the polymer is formed of a carboxyl group or a phenolic hydroxyl group. This makes use of the phenomenon that the exposed region of the resist film becomes easily soluble in an alkali developing solution. By the way, many of the conventional chemically amplified radiation-sensitive compositions are based on phenolic resins, but in the case of such resins, far-ultraviolet rays are absorbed due to aromatic rings, so that the There is a drawback that the irradiated radiation cannot reach the lower layer of the resist film sufficiently, so that the exposure amount is larger in the upper layer of the resist film, less in the lower layer, and the resist pattern after development becomes thinner in the upper part and lower in the lower part. There were problems such as a large trapezoidal shape, and a sufficient resolution could not be obtained. In addition, if the developed resist pattern has a trapezoidal shape,
That is, when performing etching, ion implantation, or the like, desired dimensional accuracy cannot be achieved, which has been a problem. Moreover,
If the shape of the upper part of the resist pattern is not rectangular, the rate of disappearance of the resist by dry etching is increased, and there is a problem that it is difficult to control the etching conditions.
On the other hand, the shape of the resist pattern can be improved by increasing the radiation transmittance of the radiation-sensitive resin composition. For example, a (meth) acrylate resin represented by polymethyl methacrylate is highly transparent to far ultraviolet rays and is a very preferable resin from the viewpoint of radiation transmittance. Discloses a chemically amplified radiation-sensitive resin composition using a methacrylate resin. However, although this composition is excellent in terms of fine processing performance,
Since it has no aromatic ring, it has a drawback of low dry etching resistance. In this case, it is also difficult to perform high-precision etching processing. The development of an amplified radiation-sensitive resin composition has been desired. On the other hand, in order to improve the dry etching resistance without impairing the transparency to far ultraviolet rays, a method of introducing an alicyclic group instead of an aromatic ring is known. For example, Japanese Patent Application Laid-Open No. Hei 7-234511. Has proposed a chemically amplified radiation-sensitive resin composition using a (meth) acrylate resin having an alicyclic group. By the way, the alkali solubility in the radiation-sensitive resin composition is a very important factor related to resolution and developability, but in the case of a resin having a carboxyl group in a side chain as disclosed in the publication, The alkali solubility is controlled by the content of the side chain carboxyl group, but there is a disadvantage that the developability of the radiation-sensitive resin composition containing the resin and the adhesiveness to a substrate are insufficient. There is a need for those improvements.

[0003]

The object of the present invention is to solve the problem that the solubility in an alkali developing solution is increased by the action of an acid generated by exposure to far ultraviolet rays typified by a KrF excimer laser or an ArF excimer laser. It is an object of the present invention to provide a radiation-sensitive resin composition having high transparency to far ultraviolet rays and excellent adhesion to a substrate as a chemically amplified resist used.

[0004]

Means for Solving the Problems According to the present invention, (A) at least one terminal of the molecular chain has the following structural formula (1) -X-COOH ... (1) [Structural formula (1) )), X represents -R ^1- , -SR ^1- , -NH-R ¹
-Or -OR ^1- represents a divalent group, and R ¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms which can have a substituent. A radiation-sensitive resin composition comprising: a resin having a group represented by formula (I) and having an increased solubility in an alkaline developer by the action of an acid; and (B) a radiation-sensitive acid generator. , Is achieved.

Hereinafter, the present invention will be described in detail. Resin (A) Resin which is the component (A) of the present invention (hereinafter referred to as “resin (A)”)
That. ) Is a resin having a group represented by the structural formula (1) at one or both ends of its molecular chain, and having increased solubility in an alkali developing solution by the action of an acid. As such a resin (A), for example, an acid functional group such as a carboxyl group or a phenolic hydroxyl group is dissociated by a group represented by the structural formula (1) and an acid, for example, an acid generated by exposure. And a resin having a group that yields The carboxyl group in the resin (A) has a greater effect on the alkali dissolution rate than the carboxyl group present on the side chain of the molecular chain, and the slight change in the carboxyl group content causes the alkali dissolution rate of the resin composition to change. Can be controlled. Moreover, there is a close correlation between the carboxyl group content in the resin and the adhesiveness to the substrate, and reducing the carboxyl group content in the resin is necessary to improve the adhesiveness to the substrate. It is effective. As a result, a radiation-sensitive resin composition containing a resin in which the carboxyl group on the side chain is reduced as much as possible has extremely excellent properties as a chemically amplified resist.

In the structural formula (1), R ¹ has 1 to 2 carbon atoms.
Examples of the divalent hydrocarbon group of 0 include a methylene group,
Ethylene group, trimethylene group, propylene group, tetramethylene group, 1,2-butylene group, 1,3-butylene group,
Alkylene groups such as 2,3-butylene group, pentamethylene group and hexamethylene group; alkylidene groups such as ethylidene group, propylidene group, i-propylidene group, butylidene group, pentylidene group and hexylidene group; 1,2-cyclopentylene Group, 1,3-cyclopentylene group, 1,2
-Cyclohexylene group, 1,3-cyclohexylene group,
Cycloalkylene groups such as 1,4-cyclohexylene group, 1,2-cycloheptylene group, 1,3-cycloheptylene group, 1,4-cycloheptylene group; 1,2-phenylene group, 1,3-phenylene group, 4-phenylene group,
Arylene groups such as 2,3-tolylene group, 2,4-tolylene group, 2,5-tolylene group, 1,4-naphthylene group; o
And aralkylene groups such as -xylylene group, m-xylylene group and p-xylylene group. Further, as a substituent for these hydrocarbon groups, for example, -C
N, -OH, -C (= O ) R 2 ( In the formula, R ² is an alkyl group having 1 to 4 carbon atoms.), - OR ³ (wherein, R ³ is alkyl of 1 to 4 carbon atoms Represents a group). Where R ²
Alternatively, examples of the alkyl group having 1 to 4 carbon atoms of R ³ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, and a t-butyl group. A butyl group and the like can be mentioned. These substituents can be present at appropriate positions on the hydrocarbon group.

The resin (A) in the present invention includes a resin represented by the following formula (2) (hereinafter referred to as “resin (A1)”) and a resin represented by the following formula (3) (hereinafter referred to as “resin (A1)”). Resin (A2) ”).

[0008]

Embedded image

[0009]

Embedded image

[In the formulas (1) and (2), R ⁴ represents an alicyclic group having 1 to 20 carbon atoms or a substituted derivative of these groups, and R ⁵ represents a 1-carbon atom dissociated by the action of an acid. -10
Shows the acid-dissociable group, R ⁶ is R ⁴ and R ⁵ other than 1 carbon atoms
R ⁷ , R ⁸ and R ⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and X represents X in the structural formula (1) Y is a residue (e.g., a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, etc.) resulting from a polymerization initiation reaction or a polymerization termination reaction; j and k indicate the number of repeating units, i and j are positive integers, and k is 0 or a positive integer. R ⁴ and R ⁵ in the formulas (1) and (2) each have a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom, or a halogen atom in their main chain and / or side chain. And the substituted alkyl group for R ⁶ can have a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom, and a halogen atom. The resin (A1) and the resin (A2) each have a repeating unit (hereinafter, referred to as a repeating unit) composed of an alicyclic group-containing acrylate derivative having a repeating unit number i.
It is called "repeating unit (I)". ) And the number of repeating units j
A repeating unit comprising an acid-labile group-containing acrylate derivative having the following formula (hereinafter referred to as “repeating unit (J)”) as an essential unit, and in some cases, a repeating unit comprising another acrylate derivative having the number k of repeating units. (Less than,
It is called "repeating unit (K)". ). However, the repeating unit (I), the repeating unit (J) and the repeating unit (K) in the resin (A1) and the resin (A2) may be arranged at random in the molecular chain of each resin, or One or more repeating units may be at least partially arranged in a block, and the -X-COOH group and the Y group located at the end of each molecular chain can be bonded to any repeating unit.

Hereinafter, the resin (A1) and the resin (A2) will be described in detail. Preferred monomers that give the repeating unit (I) include, for example, adamantyl (meth) acrylate, adamantyl methyl (meth) acrylate, methyl adamantyl (meth) acrylate, dimethyl adamantyl (meth) acrylate, tricyclodecanyl (meth) ) Acrylate, norbornyl (meth) acrylate, isobornyl (meth) acrylate, the following formula (4)

[0012]

Embedded image

[In the formula, R ¹⁰ is a hydrogen atom or a group having 1 to 1 carbon atoms.
5 represents an alkyl group, R ¹¹ , R ¹² , R ¹³ and R ¹⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, —C
N or -COOR ¹⁵ (where R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), or R ¹¹
And R ¹³ or R ¹⁴ are combined

[0014]

Embedded image Or R ¹² and R ¹³ or R ¹⁴ are bonded

[0015]

Embedded image A bicyclo [2.2.1]
Heptyl (alkyl) acrylate, the following formula (5)

[0016]

Embedded image

Wherein R ¹⁶ is a hydrogen atom or a group having 1 to 1 carbon atoms.
And R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, —C
N or -COOR ²¹ (where R ²¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), or R ¹⁷
And R ¹⁹ or R ²⁰ are combined

[0018]

Shows that R ¹⁸ is bound to R ¹⁹ or R ²⁰

[0019]

Embedded image And the like, tetracyclododecyl (alkyl) acrylate and the like.

Specific examples of the monomer represented by the above formula (4) include bicyclo [2.2.1] heptyl (meth) acrylate and 5-cyanobicyclo [2.2.1] heptyl (meth). Acrylate, 5-methylbicyclo [2.2.
1] Heptyl (meth) acrylate, 5-methoxycarbonylbicyclo [2.2.1] Heptyl (meth) acrylate, 5-carboxybicyclo [2.2.1] Heptyl (meth) acrylate, 5-ethoxycarbonylbicyclo [2 2.2.1] heptyl (meth) acrylate, 5
-N-propoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5-isopropoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5-n-butoxycarbonylbicyclo [2.
2.1] Heptyl (meth) acrylate, 5-sec-
Butoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5-t-butoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate,
5-cyclohexyloxycarboxybicyclo [2.
2.1] Heptyl (meth) acrylate, 5-methyl-
5-cyanobicyclo [2.2.1] heptyl (meth) acrylate, 5-methyl-5-methoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5
-Methyl-5-ethoxycarbonylbicyclo [2.2.
1] heptyl (meth) acrylate, 5-methyl-5
n-propoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5-methyl-5-isopropoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5-methyl-5-n-butoxy Carbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5-methyl-5-sec-butoxycarbonylbicyclo [2.2.1] heptyl (meth) acrylate, 5-methyl-5-t-butoxycarbonylbicyclo
[2.2.1] heptyl (meth) acrylate, 5-methyl-5-cyclohexyloxycarboxybicyclo [
2.2.1] Heptyl (meth) acrylate, 5,6-
Dimethylbicyclo [2.2.1] heptyl (meth) acrylate, 5,6-dicyanobicyclo [2.2.1] heptyl (meth) acrylate, 5,6-dicarboxibicyclo [2.2.1] heptyl ( Meth) acrylates,
5,6-di (methoxycarbonyl) bicyclo [2.2.
1] Heptyl (meth) acrylate, 5,6-di (ethoxycarbonyl) bicyclo [2.2.1] Heptyl (meth) acrylate, 5,6-di (n-propoxycarbonyl) bicyclo [2.2.1] Heptyl (meth) acrylate, 5,6-di (isopropoxycarbonyl) bicyclo [2.2.1] heptyl (meth) acrylate,
5,6-di (n-butoxycarbonyl) bicyclo [2.
2.1] Heptyl (meth) acrylate, 5,6-di (sec-butoxycarbonyl) bicyclo [2.2.
1] heptyl (meth) acrylate, 5,6-di (t-
Butoxycarbonyl) bicyclo [2.2.1] heptyl (meth) acrylate, 5,6-di (cyclohexyloxy) bicyclo [2.2.1] heptyl (meth) acrylate, 5,6-dicarboxybicyclo [2. 2.1]
Heptyl (meth) acrylate anhydride and the like can be mentioned.

A specific example of the monomer represented by the above formula (5) is tetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] dodecyl (meth) acrylate, 8-cyanotetracyclo [4.4.0.1 ^2,5 . [ ^7,10 ] dodecyl (meth) acrylate, 8-methyltetracyclo [4.4.
0.1 ^2,5 . 1 ^7,10 ] dodecyl (meth) acrylate,
8-carboxytetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] dodecyl (meth) acrylate, 8-methyl-8
-Cyanotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ]
Dodecyl (meth) acrylate, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] dodecyl (meth) acrylate, 8-methyl-8
-Ethoxycarbonyltetracyclo [4.4.0.1
^2,5 . 1 ^7,10 ] dodecyl (meth) acrylate, 8-methyl-8-n-propoxycarbonyltetracyclo
[4.4.0.1 ^2,5 . 1 ^7,10] dodecyl (meth) acrylate, 8-methyl-8-isopropoxycarbonyl tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10] dodecyl (meth) acrylate, 8-methyl -8-n-butoxycarbonyl tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10
] Dodecyl (meth) acrylate, 8-methyl-8-s
ec-butoxycarbonyltetracyclo [4.4.0.
^12.5 . 1 ^7,10 ] dodecyl (meth) acrylate, 8-
Methyl-8-t-butoxycarbonyltetracyclo
[4.4.0.1 ^2,5 . 1 ^7,10] dodecyl (meth) acrylate, 8-methyl -8-n-pentyloxycarbonyl tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10] dodecyl (meth) acrylate, 8-methyl-8-isopentyloxy carbonyl tetracyclo [4.4.0.1
^2,5 . [ ^1,7,10 ] dodecyl (meth) acrylate, 8,9
-Dicarboxytetracyclo [4.4.0.1 ^2,5 . 1
^7,10 ] dodecyl (meth) acrylate ^anhydride . These monomers giving the repeating unit (I) can be used alone or in combination of two or more.

Next, preferred monomers that give the repeating unit (J) include, for example, tetrahydropyranyl (meth) acrylate, tetrahydrofuranyl (meth) acrylate, t-butyl (meth) acrylate, 3-oxocyclohexyl ( (Meth) acrylate, methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, methylthiomethyl (meth) acrylate, ethylthiomethyl (meth) acrylate, methoxyethoxy (meth) acrylate, ethoxyethoxy (meth) acrylate, cyclopentyl (meth) ) Acrylate, cyclohexyl (meth) acrylate, St-butyl (meth) acrylate, S-cyclopentyl (meth) acrylate, S-cyclohexyl (meth) acrylate, isobornyl (meth) Mention may be made of acrylate, and the like. These monomers giving the repeating unit (J) can be used alone or in combination of two or more.

Further, preferable monomers for giving the repeating unit (K) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate and n-butyl. (Meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-decyl (meth) acrylate , Isodecyl, lauryl (meth) acrylate, n-tridecyl (meth) acrylate, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol mono (meth) acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, Examples thereof include tetraethylene glycol mono (meth) acrylate, glycidyl (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate. These monomers giving the repeating unit (K) can be used alone or in combination of two or more.

In resin (A1) and resin (A2), i / (i + j + k), j / (i + j + k) and k /
The range of (i + j + k) is preferably a region surrounded by the thick solid line of the triangular coordinates in FIG. 1 (including the boundary), and a more preferable range is a region surrounded by the dashed line (however,
Including on the border. ). That is, the preferable content (i / (i + j + k)) of the repeating unit (I) is 30 to 70.
Mol%, more preferably 40 to 60 mol%. When the content of the repeating unit (I) is less than 30 mol%, the dry etching resistance as a resist tends to decrease,
On the other hand, if it exceeds 70 mol%, the alkali dissolution rate of the resin composition becomes slow, and the alkali developability of the exposed portion tends to decrease. Further, the preferable content (j / (i + j + k)) of the repeating unit (J) is from 10 to 60 mol%, more preferably from 20 to 50 mol%. When the content of the repeating unit (J) is less than 10 mol%, the difference in the alkali dissolution rate between the exposed and unexposed parts tends to be small, and the resolution tends to be reduced. The sensitivity tends to decrease due to too many functional groups. The weight average molecular weight in terms of polystyrene (hereinafter, referred to as “Mw”) of the resin (A1) and the resin (A2) determined by gel permeation chromatography (GPC) is preferably 3,000.
0-100,000, more preferably 5,000-5
It is 0000. M of resin (1) and resin (A2)
When w is less than 3,000, the difference in the alkali dissolution rate between the exposed and unexposed areas becomes small, and the resolution tends to decrease. On the other hand, when w exceeds 100,000, the alkali dissolution rate in the exposed areas decreases. Therefore, the sensitivity tends to decrease.
The ratio (Mw / Mn) of Mw of the resin (A1) and the resin (A2) determined by gel permeation chromatography (GPC) to the number average molecular weight in terms of polystyrene (hereinafter, referred to as “Mn”) is as follows: Preferably 1 to 6,
More preferably, it is 1-4. When Mw / Mn of the resin (A1) and the resin (A2) is out of the range of 1 to 6,
Developability and resolution tend to decrease.

The resin (A1) and the resin (A2) are each composed of a monomer giving the repeating unit (I) and a monomer giving the repeating unit (J), and optionally a monomer giving the repeating unit (K). In addition, it can be produced by copolymerization by radical polymerization, anion polymerization, group transfer polymerization (GTP) or the like. Examples of the production of the resin (A1) and the resin (A2) include, for example, the following (A) to (A).
Method (h) can be mentioned. However, (a) ~
In the following reaction examples in the method (h), M means any monomer that gives the repeating units (I) to (K),
^* Means a repeating unit consisting of monomer M, and n is an integer representing the number of M and M ^* . (A) 1) A method of copolymerizing using a radical initiator having a -X-COOH group. A reaction example of this method is shown in the following formula.

[0026]

Embedded image

(B) 1) A method in which radical copolymerization is carried out in the presence of a chain transfer agent having an -X-COOH group. A reaction example of this method is shown in the following formula.

[0028]

Embedded image

(C) In radical copolymerization, 1) -X-CO
A method in which a radical terminator having an OH group is added at an appropriate polymerization stage. A reaction example of this method is shown in the following formula.

[0030]

Embedded image

(D) 1) After copolymerization using an anionic polymerization initiator having a -X-COOR 'group (R' represents a hydrolyzable group such as a t-butyl group), 2) ) A method of terminating polymerization with an alcohol, and then 3) hydrolyzing with an acid. A reaction example of this method is shown in the following formula.

[0032]

Embedded image

[0033]

Embedded image

(E) 1) After anionic copolymerization, 2) -X-
Polymerization is terminated by a polymerization terminator having a COOR 'group (wherein R' represents a hydrolyzable group such as a t-butyl group);
Next, 3) a method of hydrolysis with an acid. A reaction example of this method is shown in the following formula.

[0035]

Embedded image

(F) 1) Anionic copolymerization, 2) termination of polymerization with carbon dioxide, and 3) hydrolysis. A reaction example of this method is shown in the following formula.

[0037]

Embedded image

(G) Group transfer polymerization (GT)
In P), 1) after copolymerization using an enolate initiator in which two hydroxyl groups are protected with a trialkylsilyl group,
2) Hydrolysis method. A reaction example of this method is shown in the following formula.

[0039]

Embedded image

(H) A method in which a -X-COOH group is introduced by a polymer reaction using a modifiable functional group (for example, -NH ₂ , -OH, etc.) at the terminal of the resin molecular chain. A reaction example of this method is shown by the following formula (where Z represents an appropriate divalent group).

[0041]

Embedded image

[0042]

Embedded image

The performance of the radiation-sensitive resin composition of the present invention is not inferior to any of the above methods (a) to (h). In the present invention, the method for introducing the -X-COOH group into the resin (A) is not particularly limited as long as the group is present at the terminal of the molecular chain. The method described above can also be adopted.

Radiation-Sensitive Acid Generator The radiation-sensitive acid generator used in the present invention is a compound that generates an acid upon exposure, and the action of this acid causes a specific group present in the resin (A) to be formed. As a result, the exposed portion of the resist film becomes easily soluble in the alkali developing solution, and a positive resist pattern can be formed. Such a radiation-sensitive acid generator is disclosed in
0-115,932, JP-A-60-37549, JP-A-60-52845, JP-A-63-29
Compounds disclosed in JP-A-2128 and JP-A-1-293339, for example, onium salts, halogen-containing compounds, diazoketone compounds, sulfone compounds, sulfonic acid compounds and the like can be mentioned. Specific examples of these radiation-sensitive acid generators include the following. Onium salt Examples of the onium salt include an iodonium salt, a sulfonium salt, a phosphonium salt, a diazonium salt, a pyridinium salt and the like. Specific examples of preferred onium salts include diphenyliodonium triflate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzenesulfonate, bis (4-t-butylphenyl) iodonium triflate, and bis (4-t-butylphenyl) iodonium dodecylbenzene. Sulfonate, bis (4-t-butylphenyl) iodonium naphthalene sulfonate, bis (4
-T-butylphenyl) iodonium hexafluoroantimonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalene sulfonate, (hydroxyphenyl) benzenemethylsulfonium toluenesulfonate, 1- (naphthylacetomethyl) thiola Triflate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium triflate, dicyclohexyl (2-oxocyclohexyl) sulfonium triflate, dimethyl (2-oxocyclohexyl) sulfonium triflate, 4-hydroxynaphthyldimethylsulfonium triflate and the like. Can be. Halogen-containing compound Examples of the halogen-containing compound include a haloalkyl group-containing hydrocarbon compound and a haloalkyl group-containing heterocyclic compound. Specific examples of preferred halogen-containing compounds include 1,1-bis (4-chlorophenyl) -2,2,2-trichloroethane, phenyl-bis (trichloromethyl) -s-triazine, and methoxyphenyl-bis (trichloromethyl)- Examples include s-triazine, naphthyl-bis (trichloromethyl) -s-triazine and the like. Diazoketone Compound Examples of the diazoketone compound include a 1,3-diketo-2-diazo compound, a diazobenzoquinone compound, and a diazonaphthoquinone compound. Specific examples of preferred diazoketones include 1,2-naphthoquinonediazide-4-sulfonyl chloride, 2,3,4,
1,2-naphthoquinonediazide-4-sulfonic acid ester of 4′-tetrahydroxybenzophenone, 1,1,
1,2-tris (4-hydroxyphenyl) ethane 1,2
-Naphthoquinonediazide-4-sulfonic acid ester; Sulfone compound As the sulfone compound, for example, β-ketosulfone,
β-sulfonyl sulfone and the like can be mentioned. Specific examples of preferable sulfone compounds include 4-trisphenacylsulfone, mesitylphenacylsulfone, and bis (phenylsulfonyl) methane. Sulfonic acid compound Examples of the sulfonic acid compound include alkylsulfonic acid esters, alkylsulfonic acid imides, haloalkylsulfonic acid esters, arylsulfonic acid esters, and iminosulfonates. Specific examples of preferred sulfonic acid compounds include benzoin tosylate, tris triflate of pyrogallol, nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2.
2.1] Hept-5-ene-2,3-dicarboximide, N-hydroxysuccinimide triflate,
8-Naphthalenedicarboximide triflate and the like can be mentioned. Of these radiation-sensitive acid generators,
In particular, diphenyliodonium triflate, bis (4
-T-butylphenyl) iodonium triflate, triphenylsulfonium triflate, cyclohexylmethyl (2-oxocyclohexyl) sulfonium triflate, dicyclohexyl (2-oxocyclohexyl) sulfonium triflate, dimethyl (2-oxocyclohexyl) sulfonium triflate, 1- (naphthyl acetomethyl) thiolanium triflate, 4-
Hydroxynaphthyldimethylsulfonium triflate, trifluoromethanesulfonylbicyclo [2.2.
1] Hept-5-ene-2,3-dicarboximide, N
-Hydroxysuccinimide triflate, 1,8-naphthalenedicarboximide triflate and the like are preferred.
The radiation-sensitive acid generators can be used alone or in combination of two or more. The amount of the radiation-sensitive acid generator to be used is usually from 100 parts by weight of the resin (A) from the viewpoint of securing the sensitivity and developability as a resist.
0.1 to 10 parts by weight, preferably 0.5 to 7 parts by weight. If the amount of the radiation-sensitive acid generator is less than 0.1 part by weight, the sensitivity and developability decrease, and if it exceeds 10 parts by weight, the transmittance of radiation decreases and a rectangular resist pattern can be obtained. Tends to be difficult.

Further, to the radiation-sensitive resin composition of the present invention, a compound which acts as a Lewis base for an acid generated from the radiation-sensitive acid generator (hereinafter referred to as "Lewis base compound") is added. Thereby, the verticality of the side wall of the resist pattern can be more effectively improved. Examples of such a Lewis base compound include a nitrogen-containing basic compound, salts of the nitrogen-containing basic compound, carboxylic acids, and alcohols, and a nitrogen-containing basic compound is preferable. Specific examples of the nitrogen-containing basic compound include triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, tri-n-hexylamine, triethanolamine,
Triphenylamine, aniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-
Amine compounds such as methylaniline, 4-nitroaniline, 1-naphthylamine, 2-naphthylamine, diphenylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, pyrrolidine and piperidine;
Imidazole, 4-methylimidazole, 4-methyl-
Imidazole compounds such as 2-phenylimidazole and thiabendazole; pyridine, 2-methylpyridine, 4-
Ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, nicotinic acid, nicotinamide, quinoline,
Pyridine compounds such as acridine; purines, 1,3,5-
Triazine, triphenyl-1,3,5-triazine,
Other nitrogen-containing heterocyclic compounds such as 1,2,3-triazole, 1,2,4-triazole and urazole can be exemplified. These nitrogen-containing basic compounds can be used alone or in combination of two or more. The amount of the Lewis base compound to be used is generally 1 mol or less, preferably 0.05 to 1 mol, per 1 mol of the radiation-sensitive acid generator. If the amount of the Lewis base compound exceeds 1 mol, the sensitivity as a resist tends to decrease.

Further, various additives can be further added to the radiation-sensitive resin composition of the present invention, if necessary. Such additives include, for example,
Examples of the surfactant include a surfactant having an effect of improving developability. Examples of such a surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether,
In addition to nonionic surfactants such as polyoxyethylene nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate, commercially available products such as KP341 (all manufactured by Shin-Etsu Chemical Co., Ltd.) and Polyflow No. 75; 95 (all manufactured by Kyoeisha Yushi Kagaku Kogyo), F-top EF301, EF-301
303, EF352 (all, manufactured by Shin-Akita Kasei), Megafax F171, F173 (all, manufactured by Dainippon Ink & Chemicals), Florard FC430, FC431 (all, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S- 382, SC-101, SC-10
2, SC-103, SC-104, SC-10
5, SC-106 (all manufactured by Asahi Glass) and the like. The amount of the surfactant used is usually based on 100 parts by weight of the total of the resin (A) and the radiation-sensitive acid generator.
Not more than 2 parts by weight. Also, as other additives,
Examples include antihalation agents, adhesion aids, storage stabilizers, and antifoaming agents.

The radiation-sensitive resin composition of the present invention contains the resin (A) and the radiation-sensitive acid generator as essential components, and optionally contains a Lewis base compound and various additives. In doing so, the concentration of all solids
After dissolving in a solvent so as to have a concentration of, for example, 5 to 50% by weight, the composition is usually prepared as a composition solution by filtering with, for example, a filter having a pore size of about 0.2 μm. As the solvent used for preparing the composition solution, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-
n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Acetate, propylene glycol mono-n-propyl ether acetate, toluene,
Xylene, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, 2-heptanone, 3-
Heptanone, 4-heptanone, cyclohexanone, 2-
Methyl hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutyrate, 3-methoxybutyl acetate, 3-methyl -3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, methyl acetoacetate, Ethyl acetoacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide and the like can be mentioned. . These solvents are used alone or in combination of two or more. Further, the solvent, if necessary, benzyl ethyl ether, dihexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonylacetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, One or more high-boiling solvents such as benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, and phenyl cellosolve acetate can be used in combination.

Method for Forming Resist Pattern When a resist pattern is formed using the radiation-sensitive resin composition of the present invention, the composition solution prepared as described above is spin-coated, cast-coated, and roll-coated. By a suitable coating means such as coating, for example, a silicon wafer, by coating on a substrate such as a wafer coated with aluminum, to form a resist coating, optionally after pre-baking, and then a predetermined resist pattern The resist coating is exposed to form. As the radiation used at that time, far ultraviolet rays such as a KrF excimer laser (wavelength 248 nm) or an ArF excimer laser (wavelength 193 nm) are preferably used. In the present invention, it is preferable to perform a heat treatment (hereinafter, referred to as “post-exposure bake”) after the exposure. By the post-exposure bake, the dissociation of the acid-dissociable group contained in the resin (A), that is, the reaction of forming a carboxyl group proceeds smoothly in the resist film. The heating temperature varies depending on the composition of the radiation-sensitive resin composition, but is usually 30 to 200.
° C, preferably 50 to 170 ° C. In the present invention, in order to maximize the potential of the radiation-sensitive resin composition, for example, as disclosed in Japanese Patent Publication No. 6-12452, etc., an organic or inorganic based An anti-reflection film can be formed, and in order to prevent the influence of basic impurities contained in the environmental atmosphere, as described in, for example, JP-A-5-188598, a resist film is formed on the resist film. A protective film can be provided, or these techniques can be used in combination.
Next, a predetermined resist pattern is formed by developing the exposed resist film. As the developer for the radiation-sensitive resin composition of the present invention, for example,
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine , Choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene Is preferred. The concentration of the alkaline aqueous solution is usually 1
0% by weight or less. If the concentration of the alkaline aqueous solution exceeds 10% by weight, unexposed portions may be dissolved in the developer, which is not preferable. Further, for example, an organic solvent can be added to the developer composed of the alkaline aqueous solution. As the organic solvent, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, 3-methyl-2-cyclopentanone,
Ketones such as 2,6-dimethylcyclohexanone; methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, , 4-
Alcohols such as hexane dimethylol; ethers such as tetrahydrofuran and dioxane; esters such as ethyl acetate, isopropyl acetate, n-propyl acetate, n-butyl acetate and isoamyl acetate; aromatic hydrocarbons such as toluene and xylene; , Phenol, acetonylacetone, N, N-dimethylformamide and the like. These organic solvents can be used alone or in combination of two or more. The amount of the organic solvent used is preferably 100% by volume or less based on the alkaline aqueous solution. If the amount of the organic solvent used exceeds 100% by volume, the developability may be reduced and the undeveloped portion of the exposed area may be increased. In addition, an appropriate amount of a surfactant or the like can be added to a developer composed of an alkaline aqueous solution. After development with a developing solution composed of an alkaline aqueous solution, it is generally washed with water and dried.

[0049]

Embodiments of the present invention will be described below more specifically with reference to examples. However, the present invention is not limited to these embodiments. Exposure in Examples and Comparative Examples was performed by Nikon Corporation
F excimer laser exposure device (lens numerical aperture 0.55,
Exposure wavelength: 193 μm) or KrF excimer laser stepper NSR-EX8A manufactured by Nikon Corporation (lens numerical aperture: 0.50, exposure wavelength: 248 μm).
In addition, each measurement in Examples and Comparative Examples was performed in the following manner. Mw and Mw / Mn GPC columns manufactured by Tosoh Corporation (2 G2000H _XL , G3
000H _XL, one G4000H _XL ), gel permeation chromatography (GPC) with a flow rate of 1.0 ml / min, elution solvent of tetrahydrofuran, column temperature of 40 ° C. and monodisperse polystyrene as standard. It was measured. A positive line-and-space pattern (1L1S) having a line width of 0.30 μm formed by developing and then washing with water and drying the substrate.
Regarding the above, the degree of peeling of the pattern and the like was observed with an electron microscope, and the result was evaluated as “good” when no problem was observed in the adhesion to the substrate, and was judged as “bad” when a problem was observed in the adhesion to the substrate. Radiation transmissivity About a 1.0 μm-thick resist film formed by applying the radiation-sensitive resin composition on a quartz glass by spin coating,
When using an ArF excimer laser for exposure, a wavelength of 19
The transmittance was calculated from the absorbance at 3 nm, or from the absorbance at a wavelength of 248 nm when a KrF excimer laser was used for exposure, and used as a measure of transparency in the deep ultraviolet region. Sensitivity Each composition solution was coated by spin coating on a silicon wafer on a hot plate maintained at 110 ° C., and for 1 minute prebake to form a resist film having a film thickness of 0.6 .mu.m. This resist film was exposed through a mask pattern. Next, after baking for 1 minute on a hot plate kept at 90 ° C., baking was performed, followed by development with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide at 25 ° C. for 1 minute, washing with water,
After drying, a positive resist pattern was formed. At this time, an exposure amount that generates a line-and-space pattern (1L1S) having a line width of 0.35 μm in a one-to-one width was set as an optimum exposure amount, and the optimum exposure amount was set as a sensitivity. Resolution The dimension of the smallest resist pattern that was resolved when exposed at the optimum exposure amount was defined as the resolution. The degree of developable scum and the amount of undeveloped residue were observed with a scanning electron microscope.

Synthesis Example 1 Tricyclodecanyl acrylate 11.46 g (0.0
555 mol), tetrahydropyranyl acrylate6.
94 g (0.0444 mol) and 6.94 g (0.0111 mol) of 2-hydroxypropyl methacrylate
Was dissolved in 70 g of tetrahydrofuran to obtain a homogeneous solution. 0.4 g of 4,4′-azobis (4-cyanovaleric acid) having a purity of 75% by weight as a polymerization initiator was added to this solution.
(1.9 × 10 ⁻³ mol) was dissolved, and the solution temperature was increased to 70 ° C. to perform radical polymerization. After the polymerization, the reaction solution was cooled to room temperature, poured into 2 liters of hexane to cause reaggregation and precipitation of the polymer, and the precipitate was filtered. Further, the operation of re-dissolving the precipitate in 50 g of tetrahydrofuran and re-aggregating and precipitating with 2 liters of hexane was repeated twice, followed by drying under reduced pressure at 45 ° C. for 12 hours.
A white polymer having a molecular weight of 16,000 and Mw / Mn = 2.3 was obtained. This polymer is referred to as a resin (A-1).

Synthesis Example 2 Tricyclodecanyl acrylate 11.46 g (0.0
555 mol), tetrahydropyranyl acrylate6.
94 g (0.0444 mol) and 6.94 g (0.0111 mol) of 2-hydroxypropyl methacrylate
Was dissolved in 50 g of tetrahydrofuran to obtain a homogeneous solution. 0.4 g of 4,4′-azobis (4-cyanovaleric acid) having a purity of 75% by weight as a polymerization initiator was added to this solution.
After dissolving (1.9 × 10 ⁻³ mol), a white polymer having Mw = 30,000 and Mw / Mn = 3.3 was obtained in the same manner as in Synthesis Example 1. This polymer is converted into a resin (A-2)
And

Synthesis Example 3 12.15 g of tricyclodecanyl acrylate (0.0
589 mol), tetrahydropyranyl acrylate5.
51 g (0.0352 mol) and 2.36 g (0.0236 mol) of methyl methacrylate were mixed with 50 g of propylene glycol monoethyl ether acetate and 50 g of water.
Was dissolved in a mixed solvent of the above to form a homogeneous solution. In this solution,
0.4 g (1.9 × 10 ⁻³ mol) of 4,4′-azobis (4-cyanovaleric acid) having a purity of 75% by weight as a polymerization initiator
Was dissolved, and Mw = 23,
000, Mw / Mn = 1.8 to obtain a white polymer. This polymer is referred to as a resin (A-3).

Synthesis Example 4 12.15 g of tricyclodecanyl acrylate (0.0
589 mol), 5.51 g of t-butyl methacrylate
(0.0387 mol) and methyl methacrylate2.
36 g (0.0236 mol) was dissolved in 50 g of propylene glycol monoethyl ether acetate to obtain a homogeneous solution. 0.4 g of 4,4′-azobis (4-cyanovaleric acid) having a purity of 75% by weight as a polymerization initiator was added to this solution.
(1.9 × 10 ⁻³ mol) and 0.1 g (9.42 × 10 ⁻⁴ mol) of 3-mercaptopropionic acid as a chain transfer agent were dissolved, and Mw = 1 in the same manner as in Synthesis Example 1.
A white polymer having a molecular weight of 5,000 and Mw / Mn = 2.7 was obtained. This polymer is referred to as a resin (A-4).

Comparative Synthesis Example 1 12.15 g of tricyclodecanyl acrylate (0.0
589 mol), 5.51 g of t-butyl methacrylate
(0.0387 mol) and methyl methacrylate2.
36 g (0.0236 mol) of tetrahydrofuran 5
0 g to obtain a homogeneous solution. In this solution, 4,4′-azobis (isobutyronitrile) is used as a polymerization initiator.
After dissolving 0.4 g (2.44 × 10 ⁻³ mol), Mw = 27,000 and Mw / Mn in the same manner as in Synthesis Example 1.
= 2.8 was obtained. This polymer is referred to as a resin (a-1).

Comparative Synthesis Example 2 12.15 g of tricyclodecanyl acrylate (0.0
589 mol), 5.51 g of t-butyl methacrylate
(0.0387 mol) and 2.03 g of methacrylic acid
(0.0236 mol) was dissolved in 50 g of propylene glycol monoethyl ether acetate to form a homogeneous solution. After dissolving 0.4 g (2.44 × 10 ⁻³ mol) of 4,4′-azobis (isobutyronitrile) as a polymerization initiator in this solution, Mw = 2 in the same manner as in Synthesis Example 1.
A white polymer having a molecular weight of 6,000 and Mw / Mn = 2.4 was obtained. This polymer is referred to as a resin (a-2).

[0056]

【Example】

Examples 1-4 and Comparative Examples 1-2 Each resin obtained in Synthetic Examples 1-4 and Comparative Synthetic Examples 1-2,
After mixing the following radiation-sensitive acid generator, Lewis base compound and solvent to form a homogeneous solution, the pore size is 0.2 μm
To prepare a composition solution shown in Table 1 (parts are based on weight). An ArF excimer laser or K
Exposure was performed with an rF excimer laser, and various evaluations were performed. Table 2 shows the evaluation results. Radiation-sensitive acid generator (B-1) cyclohexyl (2-oxocyclohexyl) sulfonium triflate (B-2) trifluoromethanesulfonylbicyclo [
2.2.1] Hept-5-ene-2,3-dicarboximide (B-3) 1,8-naphthalenedicarboximide triflate Lewis base compound (C-1) tri-n-butylamine (C- 2) 2-hydroxypyridine solvent (D-1) ethyl 2-hydroxypropionate (D-2) n-butyl acetate (D-3) ethyl 3-ethoxypropionate

[0057]

[Table 1]

[0058]

[Table 2]

[0059]

The radiation-sensitive resin composition of the present invention has particularly high transparency to far ultraviolet rays, excellent adhesion to a substrate, and excellent sensitivity, resolution and developability.
Therefore, the radiation-sensitive resin composition of the present invention can be used very suitably, particularly as a chemically amplified resist using far-ultraviolet light, for the production of integrated circuit elements whose miniaturization is expected to further advance in the future.

[Brief description of the drawings]

FIG. 1 shows i / O ratios of resin (A1) and resin (A2).
(I + j + k), j / (i + j + k) and k / (i +
FIG. 9 is a diagram illustrating a preferable range of (j + k).

Claims (1)

[Claims] (A) At least one terminal of a molecular chain has the following structural formula: -X-COOH (where X is -R ^1- , -SR ^1- , -NH-R ¹ -or -OR ^1- And R ¹ represents a divalent hydrocarbon group having 1 to 20 carbon atoms which can have a substituent.) And the action of an acid A radiation-sensitive resin composition comprising: a resin having increased solubility in an alkali developing solution, and (B) a radiation-sensitive acid generator.