JPH1020501A - Radiation sensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation sensitive resin compsn. suppressing the generation of stationary waves and halation, excellent in resolution and pattern shape, capable of stably forming a high precision fine pattern, effectively sensitive to various radial rays such as UV, far UV, X-rays and electron beams and very effective as a chemical amplification type positive resist. SOLUTION: This radiation sensitive resin compsn. contains a radiation sensitive acid generating agent generating an acid when irradiated with active light (A), a high molecular compd. having groups which are decomposed by the action of the acid and increase solubility to an alkali developer (B) and 4-20C alkylcarboxylic acid or 4-20C fluoroalkylcarboxylic acid (C) or further contains an N-contg. basic compd. (D).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a radiation-sensitive resin composition. More specifically, radiation-sensitive suitable as a positive resist useful for ultrafine processing using various radiations such as X-rays such as KrF and ArF excimer lasers, X-rays such as synchrotron radiation, and electron beams such as electron beams. It relates to a resin composition.

[0002]

2. Description of the Related Art In the field of microfabrication represented by the manufacture of integrated circuit elements, lithography techniques that enable microfabrication on the order of sub-half micron (0.5 μm or less) have recently been used in order to obtain a higher degree of integration. Is being developed, but in the near future Quartermicron (0.1
(25 μm or less) level ultra-fine processing technology is required.
Typical resists used in conventional lithography processes are g-line (436 nm), i-line (365 nm)
However, it is said that it is theoretically extremely difficult to perform lithography at a quarter-micron level, and therefore the use of radiation having a shorter wavelength is being studied.

[0003] Examples of such radiation include the emission line spectrum of a mercury lamp, far ultraviolet rays typified by excimer laser, X-rays, and electron beams. Of these, excimer lasers have received particular attention.
As a resist suitable for such radiation irradiation (hereinafter referred to as "exposure"), a composition utilizing a chemical amplification effect obtained from a compound having an acid dissociable functional group and a radiation-sensitive acid generator is proposed. Have been.

However, in the case of a conventional resist, especially when exposed to light of a short wavelength such as an excimer laser, the reflectivity at the interface between the substrate and the resist is large, and a standing wave is generated, causing periodic fluctuations in light intensity. Then, a saw-like step is formed on the side wall of the resist pattern. Further, if there is a step on the substrate, the reflected light is not returned vertically, and the resist in the adjacent unexposed portion is exposed, so that the problem of so-called halation is likely to occur. Therefore, a method of solving the above-mentioned problem by adding an antihalation agent to the resist to reduce the light transmittance is generally adopted. However, when the anti-halation agent is added to reduce the transmittance of light, the amount of irradiation is large in the upper layer of the resist and smaller in the lower layer. The shape becomes narrower and trapezoidal as it goes to the bottom.

If the resist pattern after exposure and development has a trapezoidal shape, desired dimensional accuracy cannot be obtained in the next step, that is, etching or ion implantation, which greatly impairs semiconductor performance. In addition, when the shape of the upper portion of the resist is not rectangular when performing dry etching, the rate of disappearance of the resist at the time of etching increases, and it becomes difficult to set etching conditions. Further, for example, it is effective to increase the amount of a radiation-sensitive acid generator that generates an acid upon exposure to increase the sensitivity of a resist, but when the amount of the compound is increased, radiation is absorbed by the compound. Therefore, the amount of radiation reaching the lower part of the resist is reduced, and a large amount of acid is generated in the upper layer of the resist having a large amount of light, and a large number of acid-decomposable groups are decomposed in accordance with the amount of the acid, and the solubility in an alkaline developer is reduced. As a result, the resist pattern becomes trapezoidal as in the case where the antihalation agent is added.

[0006]

SUMMARY OF THE INVENTION In view of the above facts, the present inventors have conducted intensive studies to solve this problem. As a result, an alkylcarboxylic acid having 4 to 20 carbon atoms and an alkyl carboxylic acid having 4 to 20 carbon atoms have been studied. The addition of a compound selected from the group consisting of the following fluoroalkyl carboxylic acids improves the perpendicularity of the side walls of the resist pattern, and reduces the light transmittance or the sensitivity of the photoresist by adding an antihalation agent. The present invention has been found that a rectangular resist pattern can be obtained even when the amount of the radiation-sensitive acid generator is increased in order to increase the amount.

[0007]

That is, the present invention provides a radiation-sensitive acid generator (A) which generates an acid upon irradiation with an actinic ray, and a solubility in an alkali developing solution which is decomposed by the action of an acid. Compound (C) selected from the group consisting of a polymer compound (B) containing a group to be improved, an alkylcarboxylic acid having 4 to 20 carbon atoms and a fluoroalkylcarboxylic acid having 4 to 20 carbon atoms.
It is intended to provide a radiation-sensitive resin composition containing:

In order to bring out the effects of the present invention more remarkably, it is extremely effective to add a nitrogen-containing basic compound to the radiation-sensitive resin composition. That is, according to the present invention, a radiation-sensitive acid generator (A) that generates an acid upon irradiation with actinic rays, and a polymer containing a group that is decomposed by the action of an acid to improve the solubility in an alkali developing solution A compound (B), a compound (C) selected from the group consisting of an alkylcarboxylic acid having 4 to 20 carbon atoms and a fluoroalkylcarboxylic acid having 4 to 20 carbon atoms, and a nitrogen-containing basic compound (D) Can be provided as a preferred embodiment.

The radiation-sensitive acid generator (A) used in the present invention is a compound that generates an acid upon exposure to light, and specific examples thereof include an onium salt, a sulfone compound,
Sulfonic acid ester compounds, sulfonimide compounds,
Examples thereof include 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, and pyridinium salts. Specific examples of the onium salt compound include diphenyliodonium triflate, diphenyliodonium pyrene sulfonate, diphenyliodonium dodecylbenzenesulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium hexafluoroantimonate, and triphenylsulfonium naphthalene. Sulfonate, triphenylsulfonium camphorsulfonate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate 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, and 4-trisphenacylsulfone.

Sulfonic acid ester compound: Examples of the sulfonic acid ester compound include alkylsulfonic acid esters, haloalkylsulfonic acid esters, arylsulfonic acid esters, and iminosulfonates. Specific examples of the sulfonic acid ester compound include benzoin tosylate, pyrogallol tris triflate, pyrogallol methanesulfonic acid triester,
Nitrobenzyl-9,10-diethoxyanthracene-
Examples thereof include 2-sulfonate, α-methylol benzoin tosylate, α-methylol benzoin octane sulfonate, α-methylol benzoin trifluoromethane sulfonate, and α-methylol benzoindodecyl sulfonate.

Sulfonimide compound: As the sulfonimide compound, for example, the following formula (1)

[0014]

Embedded image

Here, X ¹ represents a divalent group such as an alkylene group, an arylene group, or an alkoxylene group, and R ₁ represents 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- (camphorsulfonyl) Oxy) 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-dicarboximide,
N- (camphorsulfonyloxy) naphthylimide,
N- (camphorsulfonyloxy) bicyclo [2.2.
1] heptane-5,6-oxy-2,3-dicarboximide;

N- (4-methylphenylsulfonyloxy) succinimide, N- (camphor-sulfonyloxy) 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-trifluoromethylphenylsulfonyloxy) 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-fluorophenylsulfonyloxy) naphthyldicarboximide and the like.

Diazomethane compound: As the diazomethane compound, for example, the following formula (2)

[0019]

Embedded image

Here, R ₂ and R ₃ may be the same or different and each represents a monovalent group such as an alkyl group, an aryl group, a halogen-substituted alkyl group and 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, and methylsulfonyl-p.
-Toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane and the like.

Among the above-mentioned radiation-sensitive acid generators, onium salts, sulfonic acid ester compounds, sulfonimide compounds and diazomethane compounds are preferred, particularly triphenylsulfonium triflate, α-methylol benzoin tosylate, α-methylol benzoin octane sulfone. Acid ester, α-methylolbenzoin trifluoromethanesulfonic acid ester, α-methylolbenzoindodecylsulfonic acid ester, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1]
Hept-5-ene-2,3-dicarboximide, N-
(Camphor-sulfonyloxy) bicyclo [2.2.1]
Hept-5-ene-2,3-dicarboximide, N-
(Camphor-sulfonyloxy) naphthyldicarboximide, bis (cyclohexylsulfonyl) diazomethane and the like are preferred. These radiation-sensitive acid generators can be used alone or in combination of two or more. However, from the viewpoint of maintaining sensitivity and developability, the amount of the radiation-sensitive acid generator is reduced by the action of an acid to an alkali developing solution. The amount is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the polymer compound (B) containing a group having improved solubility.

The polymer compound (B) containing a group which is decomposed by the action of an acid contained in the composition of the present invention to improve the solubility in an alkaline developer (hereinafter simply referred to as "polymer compound (B)") A polymer containing a repeating unit derived from t-butyl (meth) acrylate; a polymer containing a repeating unit derived from a compound in which a phenolic hydroxyl group of hydroxystyrene is substituted with a t-butoxycarbonyloxy group; A polymer containing a repeating unit derived from a compound in which a phenolic hydroxyl group of styrene is substituted with a t-butoxy group, and a polymer containing a repeating unit derived from a compound in which a phenolic hydroxyl group of hydroxystyrene is substituted with a t-butoxycarbonylmethoxy group The phenolic hydroxyl group of hydroxystyrene is 1-alkoxyalkyl Polymer containing a repeating unit derived from a compound obtained by replacing at sheet group, and the like.

Examples of the polymer containing a repeating unit derived from t-butyl (meth) acrylate include t-butyl (meth) acrylate.
Butyl (meth) acrylate / isopropenylphenol copolymer, t-butyl (meth) acrylate / isopropenylphenol / styrene copolymer, t-butyl (meth) acrylate / vinylphenol copolymer, t
-Butyl (meth) acrylate / vinylphenol / styrene copolymer, t-butyl (meth) acrylate / maleic anhydride copolymer, t-butyl (meth) acrylate / cyclohexyl (meth) acrylate copolymer, t
-Butyl (meth) acrylate / adamantyl (meth)
Acrylate copolymer, t-butyl (meth) acrylate / norbornyl (meth) acrylate copolymer, t-
Butyl (meth) acrylate / naphthyl (meth) acrylate copolymer and the like can be mentioned.

The above copolymer is obtained by subjecting the corresponding monomer to radical polymerization using azobisisobutyronitrile as an initiator or ionic polymerization such as anionic polymerization or cationic polymerization. The preferred molecular weight of the copolymer is 3,000 to 100, in terms of polystyrene equivalent weight average molecular weight (hereinafter referred to as “Mw”).
000, more preferably 5,000 to 50,000, even more preferably 8,000 to 30,000. When Mw is less than 3,000, the difference between the dissolution rates of the exposed portion and the unexposed portion of the resist in an alkaline developer is small, and the resolution tends to be poor. When Mw exceeds 100,000, the viscosity of the resist solution tends to be high, and it tends to be difficult to apply the resist uniformly on a silicon wafer.

The preferred copolymerization ratio of t-butyl (meth) acrylate in the above copolymer is 20 to 70 mol%, more preferably 25 to 60 mol%, and further preferably 30 to 70 mol%.
55 mol%. When the copolymerization ratio of t-butyl (meth) acrylate is less than 20 mol%, the difference in the dissolution rate of the exposed part and the unexposed part of the resist in an alkaline developer tends to be small, resulting in poor resolution. On the other hand, when the copolymerization ratio of t-butyl (meth) acrylate exceeds 70 mol%, the heat resistance of the resist tends to decrease.

As the polymer containing a repeating unit derived from the above-mentioned compound in which the phenolic hydroxyl group of hydroxystyrene is substituted with a t-butoxycarbonyloxy group, a part of the phenolic hydroxyl group of the hydroxystyrene (co) polymer may be replaced with t-butoxycarbonyloxy. A copolymer substituted with a -butoxycarbonyloxy group. The copolymer can be obtained, for example, by a method of reacting di-t-butyl dicarbonate with a part of hydroxyl groups of a hydroxystyrene (co) polymer or a method of copolymerizing hydroxystyrene and t-butoxycarbonyloxystyrene. Can be The hydroxystyrene (co) polymer is prepared by a known method, that is, radical polymerization, anion polymerization, or cationic polymerization using t-butoxystyrene and optionally another vinyl monomer, for example, azobisisobutyronitrile as an initiator. A phenolic hydroxyl group can be regenerated by subjecting to such ionic polymerization and then removing the t-butyl group with a strong acid such as dilute sulfuric acid, sulfonic acid, or hydrochloric acid. Other methods include (co) polymerizing a vinylphenol monomer and another vinyl monomer as necessary, and (co) polymerizing acetoxystyrene and another vinyl monomer as necessary, for example, using ammonia water. It can also be produced by a method of regenerating a phenolic hydroxyl group by hydrolysis with an aqueous solution of such a basic substance.

The preferred Mw of the above copolymer is 3,00
0 to 10,000, more preferably 5,000 to 50,
000, more preferably 5,000 to 25,000. When Mw is less than 3,000, the rectangularity of the upper portion in the cross section of the resist pattern tends to be inferior. Mw is 10
If it exceeds 000, the dissolution rate of the exposed portion of the resist in an alkaline developer tends to be small, and the sensitivity tends to be poor.
The preferred copolymerization rate of the compound in which the phenolic hydroxyl group is substituted with a t-butoxycarbonyloxy group in the above copolymer is 15 to 70 mol%, more preferably 20 to 50 mol%, and still more preferably 20 to 40 mol%. It is. When the copolymerization ratio is less than 15 mol%, the solubility of the unexposed portion in an alkaline developer is high, and the residual film ratio after development tends to decrease. When the substitution rate exceeds 70 mol%, the sensitivity tends to be poor because the amount of acid-decomposable groups to be acid-decomposed is too large to make the dissolution rate in an alkaline developer a practical value.

As the polymer containing a repeating unit derived from the above-mentioned compound in which the phenolic hydroxyl group of hydroxystyrene is substituted with a t-butoxy group, a part of the phenolic hydroxyl group of the hydroxystyrene (co) polymer may be replaced with t-butoxy group. And a copolymer substituted with a group. This copolymer is obtained by (co) polymerizing t-butoxystyrene and other monomers as necessary, and then removing the t-butyl group partially with a strong acid such as dilute sulfuric acid, sulfonic acid, or hydrochloric acid to form a phenol. A method of regenerating a phenolic hydroxyl group, by copolymerizing t-butoxystyrene, acetoxystyrene and other monomers as required, and then hydrolyzing with an aqueous solution of a basic substance such as ammonia water to regenerate a phenolic hydroxyl group Or a method of copolymerizing t-butoxystyrene, paravinylphenol and, if necessary, other monomers.

The preferred Mw of the above copolymer is 3,00
0-10,000, more preferably 4,000-50,
000, and more preferably 6,000 to 30,000. When Mw is less than 3,000, the heat resistance of the resist tends to decrease. On the other hand, if Mw exceeds 100,000, the dissolution rate of the exposed portion of the resist in an alkaline developer tends to be small and the sensitivity tends to be poor. The preferred copolymerization rate of the compound in which the phenolic hydroxyl group is substituted with a t-butoxy group in the copolymer is 10 to 50 mol%, more preferably 10 to 40 mol%, and further preferably 15 to 35 mol%.
Mol%. When the copolymerization ratio is less than 10 mol%, the residual film ratio after development tends to decrease. The copolymerization rate is 5
If it exceeds 0 mol%, the heat resistance of the resist tends to decrease.

Examples of the polymer containing a repeating unit derived from a compound in which the phenolic hydroxyl group of hydroxystyrene is substituted with a t-butoxycarbonylmethoxy group include:
A copolymer in which a part of the phenolic hydroxyl group of the hydroxystyrene (co) polymer is substituted with a t-butoxycarbonylmethoxy group is exemplified. This copolymer is obtained by adding bromoacetic acid-t- to some of the hydroxyl groups of the hydroxystyrene (co) polymer.
It can be obtained by a method of reacting butyl or a method of copolymerizing hydroxystyrene and t-butoxycarbonylmethoxystyrene. The hydroxystyrene (co) polymer is prepared by a known method, that is, radical polymerization, anion polymerization, or cationic polymerization using t-butoxystyrene and optionally another vinyl monomer, for example, azobisisobutyronitrile as an initiator. A phenolic hydroxyl group can be regenerated by subjecting to such ionic polymerization and then removing the t-butyl group with a strong acid such as dilute sulfuric acid, sulfonic acid, or hydrochloric acid. Another method is to (co) polymerize a vinylphenol monomer and another vinyl monomer as needed, and after (co) polymerizing acetoxystyrene and another vinyl monomer as needed,
For example, it can be produced by a method of regenerating a phenolic hydroxyl group by hydrolysis with an aqueous solution of a basic substance such as aqueous ammonia.

The preferred Mw of the above copolymer is 3,00
0-100,000, more preferably 5,000-50,
000. When Mw is less than 3,000, the difference between the dissolution rates of the exposed portion and the unexposed portion of the resist in an alkaline developer is small, and the resolution tends to be poor. On the other hand, if Mw exceeds 100,000, the dissolution rate of the exposed portion of the resist in an alkaline developer tends to be small and the sensitivity tends to be poor. The preferred copolymerization rate of the compound obtained by substituting the phenolic hydroxyl group with a t-butoxycarbonylmethoxy group in the copolymer is 20 to 70 mol%, more preferably 25 to 5 mol%.
0 mol%. When the copolymerization ratio is less than 20 mol%, the difference in the dissolution rate between the exposed and unexposed portions of the resist in an alkaline developer tends to be small, and the resolution tends to be poor. Also,
When the copolymerization ratio exceeds 70 mol%, the sensitivity is inferior due to too many acid-decomposable groups to be acid-decomposed to make the dissolution rate in an alkaline developer a practical value.

As the polymer containing a repeating unit derived from the above-mentioned compound in which the phenolic hydroxyl group of hydroxystyrene is substituted with a 1-alkoxyalkyloxy group, a part of the phenolic hydroxyl group of the hydroxystyrene (co) polymer may be one part. -A copolymer substituted with an alkoxyalkyloxy group. This copolymer is obtained by a method in which a vinyl ether compound is added to a part of the hydroxyl group of the hydroxystyrene (co) polymer. The preferred Mw of the copolymer is 3,000 to 100,000, more preferably 4,000 to 50,000, and still more preferably 5,000 to 25,000. When Mw is less than 3,000, the heat resistance of the resist tends to decrease. When Mw exceeds 100,000, developability tends to deteriorate. 1 phenolic hydroxyl group in the above copolymer
-The copolymerization ratio of the compound substituted with an alkoxyalkyloxy group is preferably 20 to 60 mol%, more preferably 20 to 50 mol%, and still more preferably 25 to 40 mol%.
It is. When the copolymerization ratio is less than 20 mol%, the residual film ratio tends to decrease. When the copolymerization ratio exceeds 50 mol%, heat resistance tends to decrease. The above-mentioned various polymers can be used in combination of two or more as necessary. In addition, two or more acid-dissociable groups as described above are contained in the same molecule.
It can also be used as a polymer containing more than one kind.

The carbon number used in the present invention is 4 or more and 2
0 or less alkylcarboxylic acid and 4 to 20 carbon atoms
Specific examples of the compound (C) selected from the group consisting of the following fluoroalkylcarboxylic acids (hereinafter, simply referred to as “compound (C)”) include hexanoic acid, octanoic acid, decanoic acid, lauric acid, myristic acid, hexadecane Preferred are alkylcarboxylic acids such as acids and stearic acids; and fluoroalkylcarboxylic acids such as perfluorobutyric acid, perfluorooctanoic acid and perfluorodecanoic acid. When the number of carbon atoms of the alkylcarboxylic acid or the fluoroalkylcarboxylic acid is less than 4, the effect of improving the verticality of the pattern side wall is unpreferably low. On the other hand, if the number of carbon atoms exceeds 20, the solubility of the alkyl carboxylic acid or fluoroalkyl carboxylic acid in the resist solution is reduced, and phase separation is apt to occur.
The carbon number of these compounds (C) is more preferably from 6 to
18, more preferably 8 to 16.

The preferable addition amount of the above-mentioned alkylcarboxylic acid is preferably 0.1 to 100 parts by weight of the resin component.
To 20 parts by weight, more preferably 0.3 to 10 parts by weight, most preferably 0.5 to 5 parts by weight. If the addition amount is less than 0.1 part by weight, the effect of improving the pattern perpendicularity tends to be low, and if the addition amount exceeds 20 parts by weight, the alkali solubility of the resist becomes too high and the resolution is lowered and the pattern shape is reduced. Tends to deteriorate. The preferable addition amount of the fluoroalkylcarboxylic acid is 0.01 to 100 parts by weight of the polymer compound (B).
It is 2 parts by weight, more preferably 0.03 to 1.5 parts by weight, most preferably 0.05 to 1 part by weight. Addition amount is 0.01
If the amount is less than 2 parts by weight, the effect of improving the pattern perpendicularity tends to be low, and if the amount exceeds 2 parts by weight, the resist profile tends to have a reverse taper.

Further, by adding the nitrogen-containing basic compound (D) to the composition of the present invention, the storage stability of the composition can be further improved, and the process stability can be further improved. As the nitrogen-containing basic compound (D), a nitrogen-containing organic compound whose basicity is not changed by exposure or baking is preferable, and specific examples thereof include a compound represented by the general formula R ₄ R ₅ R ₆ N
Wherein R ₄ , R ₅ and R ₆ may be the same or different and each represent a hydrogen atom, an alkyl group, an aryl group or an aralkyl group;
₇ R ₈ R ₉ NRNR ₁₀ R ₁₁ R ₁₂ (R ₇ , R ₈ , R ₉ , R ₁₀ , R
₁₁ and R ₁₂ may be the same or different,
A hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and R represents an alkylene group, an arylene group, an aralkylene group or an alkyleneoxy group); a diamino compound containing an amino group in the main chain or side chain Other polyamino compounds (hereinafter, simply referred to as "polyamino compound"); amide group-containing compounds; urea compounds; nitrogen-containing heterocyclic compounds, and the like.

As the above monoamino compound, for example, n
Alkylamines such as hexylamine, n-heptylamine, n-octylamine, n-nonylamine and n-decylamine; di-n-butylamine, di-n-pentylamine, di-n-hexylamine and di-n-heptyl Dialkylamines such as amine, di-n-octylamine, di-n-nonylamine and di-n-decylamine; triethylamine, tri-n-propylamine, tri-n
-Butylamine, tri-n-pentylamine, tri-n
-Hexylamine, tri-n-heptylamine, tri-
n-octylamine, tri-n-nonylamine, tri-
trialkylamines such as n-decylamine; aniline, N-methylaniline, N, N-dimethylaniline,
Aromatic amines such as 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, and naphthylamine; pyrrolidine, piperidine, morpholine, 4-methylmorpholine, piperazine, and 1,4- And cyclic amines such as dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane.

Examples of the diamino compound include ethylenediamine, N, N, N ', N'-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane,
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,
Examples thereof include 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene and 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene.

Examples of the polyamino compound include polyethyleneimine, polyallylamine, and dimethylaminoethylacrylamide polymers. Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, and the like. No. Examples of the urea compound include urea, methylurea,
1,1-dimethylurea, 1,3-dimethylurea, 1,
Examples thereof include 1,3,3-tetramethylurea, 1,3-diphenylurea, and tributylthiourea. Examples of the nitrogen-containing heterocyclic compound include imidazole compounds such as imidazole, benzimidazole, 4-methylimidazole and 4-methyl-2-phenylimidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, N-methyl-
Pyridine compounds such as 4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, and acridine; pyrazine, pyrazole, pyridazine, quinosaline, and purine. Among these nitrogen-containing compounds, a monoamino compound and a nitrogen-containing heterocyclic compound are preferred. Also, among the amino compounds, trialkylamines are particularly preferable, and among the nitrogen-containing heterocyclic compounds, pyridine compounds are particularly preferable.

Further, by adding an antihalation agent to the composition of the present invention, scuffing of a pattern and fluctuation of a line width on a stepped substrate can be further suppressed,
Further, the influence of the standing wave can be reduced. As such an antihalation agent, a compound that efficiently absorbs irradiation radiation is preferable. When KrF excimer light having a wavelength of 248 nm is used as the radiation, for example, 2,4-pentadiene is used as a compound that absorbs this radiation. Conjugated polyene compounds such as acid, sorbic acid, 2,4-hexadien-1-ol, 2,4-hexadienal, mesityl oxide; benzonitrile, nitrophenyl, biphenyl, p-terphenyl, stilbene, cinnamic acid Substituted benzene compounds such as, cinnamate, vinylphenol, nitrophenol, isopropylphenol, fluorene, fluorenone, benzophenone;
Naphthalene, naphthol, naphthoic acid, anthracene,
Examples include polycyclic aromatic compounds such as 9-cyanoanthracene, anthracene-9-methanol, phenanthrene, phenanthrene-9-carbaldehyde, 9-phenanthrol, berylene and azylene. Among them, polycyclic aromatic compounds are preferred because of their high absorption coefficient. These antihalation agents have a transmittance of radiation used for exposure of 2 in the thickness of the resist film before exposure.
It is preferably adjusted and blended so as to be 0 to 60%, preferably 30 to 50%, more preferably 35 to 45%.

Further, various additives may be further added to the composition of the present invention, if necessary. Such additives include, for example, surfactants that have the effect of improving coatability, developability, and the like. Examples of such a surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyethylene glycol dilaurate,
Nonionic surfactants such as polyethylene glycol distearate, as commercial products, for example, KP341 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, No.
95 (trade name, manufactured by Kyoeisha Yushi Kagaku Kogyo), F-Top EF301, EF303, EF352 (all manufactured by Shin-Akita Kasei), Megafac F171, F173 (all manufactured by Dainippon Ink), Florard FC430, the same FC
431 (Sumitomo 3M), Asahi Guard AG
710, Surflon S-382, SC-101, S
C-102, SC-103, SC-104, SC
-105 and SC-106 (all manufactured by Asahi Glass). The amount of the surfactant is preferably not more than 2 parts by weight per 100 parts by weight of the total of the radiation-sensitive acid generator (A) and the polymer compound (B). Other additives include an adhesion aid, a storage stabilizer, and an antifoaming agent.

The composition of the present invention comprises the aforementioned radiation-sensitive acid generator (A), polymer compound (B), and a compound having 4 to 2 carbon atoms.
0 or less alkylcarboxylic acid and 4 to 20 carbon atoms
It comprises a compound (C) selected from the group consisting of the following fluoroalkylcarboxylic acids, and, if necessary, a nitrogen-containing basic compound (D), an antihalation agent, and various additives. 5 min concentration
After being dissolved in a solvent so as to have a concentration of about 50% by weight, it is usually prepared as a solution by filtration through a filter having a pore size of about 0.2 μm.

In the present invention, the solvent used for preparing the solution includes, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Acetate, propylene glycol monopropyl ether acetate, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, 3-heptanone, 4-heptanone, cyclohexanone, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, 2-hydroxy -2-meth Ethyl propionate, ethoxyethyl acetate, hydroxyethyl acetate, 2-hydroxy-3-
Methyl methylbutyrate, 3-methoxybutyl acetate, 3
-Methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, pyruvate Methyl, ethyl pyruvate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-
Dimethylacetamide and the like.

The solvent may be, if necessary, benzyl ethyl ether, dihexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonylacetone, isophorone,
With high boiling solvents such as caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, and phenyl cellosolve acetate. They can be used together.

[0045] When the composition of the formation the present invention of a resist pattern to form a resist pattern, the composition solution prepared as described above, rotational coating, cast coating, an appropriate application method such as roll coating For example, a resist film is formed by coating on a substrate such as a silicon wafer or a wafer coated with aluminum, and a heat treatment (hereinafter referred to as
After that, exposure is performed through a predetermined mask pattern. The radiation used at that time may be, for example, i depending on the type of the radiation-sensitive acid generator.
Ultraviolet rays such as X-ray (wavelength 365 nm); Far ultraviolet rays such as ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm); X-rays such as synchrotron radiation; I do. Among them, ArF excimer laser, K
An rF excimer laser and an electron beam are preferably used. Exposure conditions such as the exposure amount 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, it is preferable to perform a heat treatment after exposure (hereinafter, referred to as “post-exposure bake”). The heating conditions vary depending on the composition of the composition of the present invention, the type of each additive, and the like.
° C, preferably 40 to 150 ° C. Next, a predetermined resist pattern is formed by subjecting the exposed resist film to alkali development with an alkali developer. Examples of the alkali developer include mono-, di- or tri-alkylamines; mono-, di- or tri-
Alkanolamines; heterocyclic amines, tetraalkylammonium hydroxide, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-
Alkaline compounds such as diazabicyclo- [4.3.0] -5-nonene are usually added in an amount of 1 to 10% by weight, preferably 1 to 10% by weight.
An alkaline aqueous solution dissolved to a concentration of about 5% by weight is used. In addition, a water-soluble organic solvent such as methanol or ethanol or a surfactant can be appropriately added to the developer composed of 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.

[0047]

The embodiments of the present invention will be described more specifically below with reference to examples and comparative examples. However, the present invention is not limited to these embodiments. Measurement of Mw, number average molecular weight in terms of polystyrene (hereinafter, referred to as “Mn”) and Mw / Mn, measurement of light transmittance, and evaluation of each resist in Examples and Comparative Examples were performed in the following manner. Mw and Mn (Mw / Mn) GPC columns manufactured by Tosoh Corporation (2 G2000H _XL ,
G3000H _XL one, G4000H _XL one)
The measurement was carried out by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under the analysis conditions of a flow rate of 1.0 ml / min, an elution solvent of tetrahydrofuran, and a column temperature of 40 ° C. After exposing the resist film formed on a resolution silicon wafer, is performed immediately post-exposure bake, and then developed with an alkali developer, and washed with water and dried, when forming a resist pattern, the line width of 0.26μm reticle Use line width 0.
26 μm line and space pattern (1L1
The exposure amount for forming S) is 0.26Eop, and 0.26Eop
The minimum dimension (μm) of the resist pattern resolved when exposed in op was defined as the resolution.

1 L of 0.26 μm line width formed on a pattern-shaped silicon wafer
The lower side dimension La and the upper side dimension Lb of the 1S pattern section were measured with a scanning electron microscope, and 0.8 <Lb / L
When a <1.2, the pattern shape is good; 0.8 ≧ Lb /
When La, the pattern shape is forward tapered; Lb / La ≧
At the time of 1.2, the pattern shape was evaluated as a reverse taper. Measurement of light transmittance The composition solution was spin-coated on a 2-inch diameter quartz wafer and baked at 90 ° C. for 120 seconds using a hot plate to obtain a resist film having a thickness of 0.7 μm. Hitachi, Ltd. The transmittance of the coating film at a wavelength of 248 nm was measured using an ultraviolet spectrometer U3210 manufactured by U.S.A.

Production Example 1 of Polymer Compound (B) Synthesis Example 1 (t-butyl acrylate / isopropenylphenol copolymer) 67 g (0.5 mol) of p-isopropenylphenol and 64 g (0.5 mol) of t-butyl acrylate ) Is dissolved in 131 g of propylene glycol monomethyl ether, and azobisisobutyronitrile (hereinafter, “AIBN”) is dissolved.
After the addition of 8 g, polymerization was carried out for 10 hours while maintaining the reaction temperature at 60 ° C. under a nitrogen atmosphere. After the polymerization, the reaction solution was dropped into 5 liters of hexane and solidified to obtain a white polymer compound (B-1). This copolymer has M
w = 12400, Mw / Mn = 1.66 (all converted to polystyrene; the same applies hereinafter). As a result of analysis by ¹³ C-NMR, the copolymerization ratio (molar ratio) of p-isopropenylphenol and t-butyl acrylate was determined. ) Was 50:50.

Synthesis Example 2 (p-hydroxystyrene / pt-butoxycarbonyloxystyrene copolymer) 500 g of pt-butoxystyrene and 500 g of propylene glycol monomethyl ether were placed in a 2-liter separable flask, and 25 g of AIBN was added. 2.5 g of t-dodecyl mercaptan was added and polymerized at 75 ° C. for 8 hours. After the polymerization, the reaction solution was washed with a mixed solution of hexane, methanol and water to remove low molecular components of the polymer. Next, a 10% by weight aqueous sulfuric acid solution was added to the polymer solution in which the solvent was replaced with propylene glycol monomethyl ether, and 90 ° C.
For 6 hours to remove the t-butyl group in the polymer to obtain polyhydroxystyrene. After the polyhydroxystyrene was washed with water to remove the acid, the solvent was replaced with ethyl acetate. To a solution of polyhydroxystyrene in ethyl acetate, 30 mol% of di-t-butyl dicarbonate and 33 mol% of triethylamine based on hydroxyl groups in polyhydroxystyrene were added, and reacted at 60 ° C. for 6 hours. After washing the excess amine with water, the solvent was replaced with ethyl lactate to obtain a solution of the polymer compound (B-2). The obtained polymer compound had Mw = 11,400 and Mw / Mn = 1.48. When the obtained polymer compound was measured by ¹³ C-NMR, 29.7 mol% of the hydroxyl groups in the copolymer had been chemically modified.

Synthesis Example 3 (p-hydroxystyrene / pt-butoxystyrene copolymer) 176 g (1.0 mol) of pt-butoxystyrene and p
-324 g (2.0 mol) of acetoxystyrene and 500 g of propylene glycol monomethyl ether are placed in a 2-liter separable flask, and 25 g of AIBN and t
Add 2.5 g of dodecyl mercaptan and add 7 g at 75 ° C.
Polymerized for hours. After the polymerization, the reaction solution was dropped into 10 liters of hexane and solidified to give a white copolymer (yield 7).
7%). This copolymer was dissolved in methanol, 1% by weight aqueous ammonia containing twice the amount of ammonia of the acetoxy group in the copolymer was added, and the mixture was stirred at 50 ° C. for 3 hours. Thereafter, the polymer compound solution was poured into a large amount of water, and reprecipitation, filtration, and water washing were performed to obtain a solid polymer compound. GPC measurement of the obtained polymer compound showed that Mw = 1.
5,500, Mw / Mn = 1.53. When the obtained resin was measured by an infrared spectrometer, the acetoxy group was 100% decomposed. The composition ratio of p-hydroxystyrene and pt-butoxystyrene in the present polymer compound is
It was 68:32 as measured by ¹³ C-NMR. The polymer (B-
A solution of 3) was obtained.

Synthesis Example 4 (p-hydroxystyrene / pt-butoxycarbonylmethoxystyrene copolymer) Same as Synthesis Example 2 except that the amount of AIBN was changed to 8.7 g and t-dodecylmercaptan was changed to 1.25 g. By the operation described above, an ethyl acetate solution of polyhydroxystyrene was obtained. In a solution of the polymer in ethyl acetate, add 3
0 mol% of t-butyl bromoacetate was added, ion-exchanged water having the same weight as the solution of the polymer in ethyl acetate, and 102 mol% of potassium carbonate of t-butyl bromoacetate,
Then, 10 parts by weight of tetrabutylammonium bromide of tert-butyl bromoacetate was added and reacted at 70 ° C. for 7 hours. The reaction solution was washed with water, and the solvent was replaced with ethyl lactate to obtain a solution of the polymer compound (B-4). GPC measurement of the obtained polymer compound showed that Mw = 23,40.
0, Mw / Mn = 1.67. The obtained resin by ¹ H
As measured by -NMR, 29.4 mol% of the hydroxyl groups in the resin were chemically modified.

Synthesis Example 5 (p-hydroxystyrene / p-1-ethoxyethoxystyrene copolymer) 500 g (1.0 mol) of pt-butoxystyrene and 500 g of tetrahydrofuran were put into a 2-liter separable flask. After cooling to −15 ° C. and polymerizing for 1 hour using n-butyllithium as a polymerization initiator, methanol was added to terminate the reaction. Thereafter, the obtained polymerization solution was treated in the same manner as in Synthesis Example 2 to remove the t-butyl group in the polymer to obtain poly (p-hydroxystyrene), which was then dropped into a large amount of water to produce a solid. The polymer was filtered and dried to obtain a polymer powder. After dissolving 24 g of this polymer powder in 100 ml of dioxane, bubbling was performed with nitrogen for 30 minutes. To this solution, 6 g of ethyl vinyl ether and 1 g of pyridinium p-toluenesulfonate as a catalyst were added and reacted for 12 hours. After the reaction, 1 part by weight of aqueous ammonia was added dropwise, and the formed precipitate was filtered and dried in a vacuum dryer at 50 ° C. overnight to obtain a polymer compound (B-5) powder. GPC measurement of the obtained polymer compound showed that Mw = 19,000 and Mw /
Mn was 1.10. When the obtained resin was measured by ¹ H-NMR, 39.0 mol% of the hydroxyl groups in the resin were chemically modified.

Example 1 Using the polymer compound (B-1) obtained in Synthesis Example 1, 1.5 parts by weight of triphenylsulfonium triflate and 2 parts by weight of lauric acid per 100 parts by weight of solids of the polymer compound Of trioctylamine and 0.1 part by weight of trioctylamine, and diluted with ethyl lactate so that the solid concentration of the polymer compound became 20%. This was mixed with 1 part by weight of anthracene methanol to obtain a composition. The light transmittance of this composition was 40%. This composition was spin-coated on a silicon wafer, and baked at 90 ° C. for 120 seconds using a hot plate to form a resist film having a thickness of 0.7 μm. Using this as the light source of a KrF excimer laser, NA =
0.50 stepper (Nikon stepper NS)
R-2005EX08), using a hot plate, exposing at 110 ° C. for 120 seconds, baking, developing with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide, rinsing with ultrapure water, and rinsing. Width 0.
A 26 μm line-and-space positive pattern (1L1S) was obtained. The results are shown in Table 1.

Examples 2 to 6 Using the polymer compounds (B1 to B5) obtained in Synthesis Examples 1 to 5 and adding the additives shown in Table 1, a composition was obtained in the same manner as in Example 1. Was. Each of these compositions had a light transmittance of 40%. Using this, a resist pattern was obtained in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 As shown in Table 1, a composition was prepared in the same composition as in Example 1 except that lauric acid was not added. Using this, a resist pattern was obtained in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 2 As shown in Table 1, a polymer compound (B-1) was used.
A composition was prepared by adding 3 parts by weight of propionic acid to 100 parts by weight of the polymer compound solids. Using this, a resist pattern was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0058]

[Table 1]

[0059]

[Table 2]

Here, the radiation-sensitive acid generator (acid generator), nitrogen-containing basic compound (nitrogen compound), alkylcarboxylic acid or fluoroalkylcarboxylic acid (carboxylic acids) and the solvent in each of Examples and Comparative Examples are as follows. , As follows. Acid generator A-1: triphenylsulfonium triflate A-2: N- (camphorsulfonyloxy) naphthyldicarboximide A-3: bis (cyclohexylsulfonyl) diazomethane carboxylic acids C-1: lauric acid C-2: par Fluorooctanoic acid C-3: Propionic acid nitrogen compound D-1: Nicotinamide D-2: Trioctylamine Antihalation agent H-1: Anthracene methanol Solvent EL: Ethyl lactate PGMEA: Propylene glycol monomethyl ether acetate

[0061]

According to the radiation-sensitive resin composition of the present invention, the verticality of the side wall of the resist pattern is improved, and the anti-halation agent is added to reduce the light transmittance or to increase the sensitivity of the photoresist. Even when the amount of the radiation-sensitive acid generator is increased, a rectangular resist pattern can be obtained. In addition, the radiation-sensitive resin composition of the present invention effectively responds to various kinds of radiation such as ultraviolet rays, far ultraviolet rays, X-rays, and electron beams, and is extremely useful as a chemically amplified positive resist. Therefore, the radiation-sensitive resin composition of the present invention can be suitably used for manufacturing semiconductor devices, which are expected to be further miniaturized in the future.

Claims (1)

[Claims] 1. A high-molecular-weight composition containing (A) a radiation-sensitive acid generator that generates an acid upon irradiation with actinic rays, and (B) a group that improves the solubility in an alkali developing solution by being decomposed by the action of an acid. Molecular compound and (C) carbon number 4
A radiation-sensitive resin composition comprising a compound selected from the group consisting of alkyl carboxylic acids having at least 20 or less and fluoroalkyl carboxylic acids having at least 4 and at most 20 carbon atoms.