JPS6236657A - Resist composition - Google Patents

Abstract

PURPOSE:To obtain a resist composition capable of well wetting a substrate and forming a coat film uniform thickness without leaving any noncoated part, and high-precision fine processing by using the resist composition consisting of an alkali-soluble resin, a specified organic solvent, a fluorinated surfactant, and a radiation sensitive material. CONSTITUTION:The resist composition consists of (a) the alkali-soluble resin, (b) at least one kind of organic solvent selected from methyl cellosolve acetate, 'diglyme(R)', cyclopentanone, cyclic lactone, alkylene carbonate, alkyl acetate, and monooxymoncarboxylic acid, (c) the fluorinated surfactant, preferably, in an amount of 0.0005-1pt.wt. per 100pts.wt. of the alkali-soluble resin (a), and (d) the radiation sensitive material, such as quinonediazido compounds, diazo compounds, aromatic azido or diazido compounds, and polyolefinsulfones.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a resist composition, which is particularly improved in that it can form a uniform coating film without uneven coating, and is useful in the manufacture of semiconductor integrated circuits, etc. The present invention relates to a resist composition suitable as a resist for microfabrication used in.

[Conventional technology]

In the manufacture of semiconductors, semiconductor integrated circuits, etc. using various lathography techniques, in order to form highly accurate fine resist patterns that faithfully reproduce the mask, resist compositions are required to improve sensitivity to radiation such as resolution and sensitivity. In addition to being excellent in this respect, it is also required to be able to form a coating film with uniform thickness without coating unevenness.

However, conventional resist m-oxides have a problem of causing coating unevenness called striation. This striation is an uneven coating that occurs when a resist composition is applied onto a substrate by spin coating, and when visually observed, it appears as a radial striped pattern, and usually consists of wavy undulations with several hundred differences in height. I am doing it.

When this striation occurs, the linearity and reproducibility of the pattern deteriorates, resulting in a problem that a resist pattern with required accuracy cannot be formed.

Furthermore, recently, substrates such as silicon wafers have tended to have larger diameters, which causes the problem that unpainted areas tend to occur when a resist composition is applied onto the substrate.

[Problem that the invention seeks to solve]

The present invention solves the problem of conventional resist compositions, which tend to cause coating unevenness such as striation, and forms a coating film that has good wettability to the substrate and has a uniform thickness without any unpainted areas. An object of the present invention is to provide a resist composition that can achieve highly accurate microfabrication.

[Means for solving problems]

The above problem is solved by: (5) an alkali-soluble resin; (b) at least one organic solvent selected from methyl cellosolve acetate, diglyme, cyclopentanone, cyclic lactone, alkylene carbonate, acetic acid alkyl ester, and monooxymonocarboxylic acid ester; The present invention is solved by a resist composition characterized by comprising a fluorinated heterosurfactant, tel, and a radiation-sensitive substance.

That is, the resist composition of the present invention is characterized in that it is constituted by dissolving a radiation-sensitive substance together with an alkali-soluble resin in a specific organic solvent, and further uses a fluorine-based surfactant as an additive.

The present invention will be explained in detail below.

The alkali-soluble resin used in the present invention may be any resin that is soluble in the alkaline solution constituting the resist pattern developer (for example, phenol, cresol, xylenol, resorcinol, phloroglucinol, quinone). Novolac resin, p-vinylphenol, m -vinylphenol,
Vinyl phenol compounds such as 0-vinylphenol and α-methylvinylphenol, and polymers or copolymers of these halogen-substituted compounds; acrylic acid-based or methacrylic acids such as acrylic acid, methacrylic acid, hydroxyethyl acrylate, and hydroxyethyl methacrylate; Modified resins in which radiation-sensitive groups such as quinonediazide groups, naphthoquinonediazide groups, aromatic azide groups, and aromatic cinnamoyl groups are introduced through a portion of the hydroxyl groups of the various resins mentioned above. These resins can be used in combination.

Organic solvents used in the present invention include methyl cellosolve acetate; diglyme; cyclopentanone; cyclic lactones such as T-butyrolactone, β-propiolactone, and δ-valerolactone; alkylene carbonates such as ethylene carbonate and propylene carbonate; acetic acid Alkyl acetate esters such as isoamyl, hexyl acetate; and monooxymonocarboxylic acid esters, such as alkyl oxyacetates such as methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate, methyl methoxy acetate, ethyl methoxy acetate, butyl methoxy acetate, ethoxy Alkoxyalkyl acetates such as methyl acetate and ethyl ethoxyacetate; alkyl 3-oxypropionates such as methyl 3-oxypropionate and ethyl 3-oxypropionate; methyl 3-methoxypropionate and ethyl 3-methoxypropionate; Alkyl 3-alkoxypropionate, methyl 2-oxypropionate, ethyl 2-oxypropionate, 2
-alkyl 2-oxypropionates such as propyl oxypropionate, ethyl 2-methoxypropionate,
Alkyl 2-alkoxypropionates such as propyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, methyl 2-oxy-2-methylpropionate, 2-oxy-2-methylpropionate Alkyl 2-oxy-2-methylpropionates such as ethyl, methyl 2-methoxy-2-methylpropionate, alkyl alkoxy-2-methylpropionate such as methyl 2-ethoxy-2-methylpropionate, 2- methyl oxy-3-methylbutanoate,
Alkyl 2-oxy-3-methylbutanoates such as ethyl 2-oxy-3-methylbutanoate, 2-methoxy-3
- methyl methylbutanoate, methyl 2-ethoxy-3-methylbutanoate, ethyl 2-methoxy-3-methylbutanoate, ethyl 2-ethoxy-3-methylbutanoate, etc.
-Alkoxy-3-methylbutanoic acid alkyls can be mentioned. These organic solvents may be used alone or in combination, and may be used in combination with organic solvents other than those mentioned above. Examples of organic solvents other than those mentioned above include aromatic solvents such as toluene, xylene, and ethylbenzene;
Examples include ether solvents such as ethyl cellosolve, methyl cellosolve, and ethyl cellosolve acetate, cyclic ether solvents such as dioxane, trioxane, and tetrahydrofuran, and aliphatic solvents such as n-butyl acetate. At this time, the proportion of methyl cellosolve acetate, diglyme, cyclopentanone, cyclic lactone, alkylene carbonate, acetic acid alkyl ester, and monooxymonocarboxylic acid ester in the organic solvent is usually 60 to 100% by weight, preferably 70 to 100% by weight. %,
Particularly preferred is 80 to 100% by weight. The amount of organic solvent used varies depending on the required film thickness or coating method when applying the resist composition, but is usually 80 to 1,800 parts by weight per 100 parts by weight of the solid content of the resist composition.
Parts by weight, preferably 250 to 1300 parts by weight.

Examples of the fluorine-based surfactant used in the present invention include (meth)acrylate polymers having a fluorinated alkyl group in the side chain, preferably having a number average molecular weight of 30,000 or less in terms of standard polystyrene. , more preferably in the range of 2,000 to 10,000. If the number average molecular weight of the (meth)acrylate polymer exceeds 30,000, the effect of improving coating properties will not be sufficient.

In the (meth)acrylate polymer, the acrylate structural unit or methacrylate structural unit of the moiety having a fluorinated alkyl group in the side chain is, for example, the following general formula % formula % (wherein, R is a hydrogen atom or a methyl group, , n is 0~
20, a represents an integer of O to 2, and b represents an integer of O to 1) or the following general formula (wherein R is a hydrogen atom or a methyl group, and n is 1 to
10, m is an integer from 0 to 20, and a is an integer from θ to 2), specifically CHg CH- -cHt -CH- -CH! -CH- -CH! -CH- -CH, -CH- -CH, -CH- -CH, -CH- -CH, -CH- -CH2-CH- -CH! -CH- CHt CH- -CH, -CH- -CH, -CH- -CH, -CH- -cHz -CH- -CH2-CH- -CH, -CH- -CH, -CH- -CH, - CH- -CH, -CH- -CH, -CH- -CH, -CH- CH.

CH.

CH.

CH.

Hs CH.

CHs CHs CH3 -CH2-CH- -CHt　-CH- -CH, -CH- Hx H3 CH co Hs CH* CH- -CH, -CH- CH3 CH.

CH! 1 CH3 and the like. The (meth)acrylate polymer having a fluorinated alkyl group in the side chain preferably further has an alkylene oxide group or an alkyl group in the side chain.(meth)acrylate having a fluorinated alkyl group in the side chain As the acrylate structural unit or methacrylate structural unit of the part having an alkylene oxide group in the side chain in the polymer, for example, the following general formula (wherein R represents a hydrogen atom or a methyl group, and n is 1 to
6 and m are integers from 1 to 10), specifically, KAIYAMA 0H -CH, -CH- -cHt -CH- -CH□ -CH- SCz Ha OH Examples include CH, Hs, Hx, and CH.

In addition, as the acrylate structural unit or methacrylate structural unit of the part having an alkyl group in the side chain in the (meth)acrylate polymer having a fluorinated alkyl group in the side chain, for example, the following general formula (wherein R is a hydrogen atom or It is a methyl group, and n represents an integer of 1 to 22.) Specifically, examples thereof include the following.

Furthermore, the (meth)acrylate polymer having a fluorinated alkyl group in the side chain may have an aryl group, arylene group, etc. in the side chain. Examples of the structural unit include:

Furthermore, it has an alkyl fluoride in the side chain used in the present invention (
The meth)acrylate polymer may have structural units other than those mentioned above, such as.

Also, C? F ts COz NH-1CsF+tSO
zN <czHs> CHICOOK.

C*F 17s OtN HC5HhN (CH3)z
c 11C? F+5CONH(CH*)sN (CH
s)zczHnCOO-1C8FiffSO! N (
CzHs)CIH, (QC,Ha)sOH.

C7F IsCON HC5HhN (CHz)z(
CH2)2CO0-1Ch F r s S Otru C
zHiN” (CH2) t, CIFiffSOIN-(
CI-1x)ffN ((,Ha)zCHzCOO-
5xHq CtlF I? S Oz N HCs Hh N
+(CHs) z-CxHsO5-OzOCzHs
, CtF IsCON HC3H4N+(CHs)sc
J-1C1H.

Cs F I? S Oz N (CH3) CHx
Fluorine surfactants such as CCH=C'Ht can also be used.

Further, as the fluorine-based surfactant in the present invention, commercially available products can be used, such as Surflon rS-38J
, rs-382J, rsc-101J, rSC-102
J, rSC-103J, rSC-104J (all manufactured by Asahi Glass), Florado rFC-430'', rFC
-431J, rFC-173J (all fluorochemicals - manufactured by Sumitomo 3M), Eftonbur rEF352
J, rEF301J, rEF303” (all manufactured by Shin Akita Kasei), Schwego Fluor R 8035 J,
r8036J (both made by Schwegmann), r
Examples include BMloooJ, rBM)ooJ (both manufactured by BM Himy).

The fluorine content of the fluorine-based surfactant in the present invention is usually 5 to 80% by weight, preferably 8 to 65% by weight.

The various fluorosurfactants mentioned above can be used alone or in combination.

The fluorine-based surfactant used in the present invention is 0.00 parts by weight per 100 parts by weight of the alkali-soluble resin constituting the resist composition.
It is desirable to use it in a proportion of 0001 to 2 parts by weight, preferably o,oos to 1 part by weight, the proportion used is 0.0
If the proportion is less than 0.001 parts by weight, the effect of preventing striation will be insufficient, and if the proportion exceeds 2 parts by weight, the softening temperature of the composition will decrease.

The radiation-sensitive substance used in the present invention is mixed with the alkali-soluble resin and then exposed to radiation such as ultraviolet rays.
Any substance that can change the solubility of an alkali-soluble resin in a developer by irradiation with far ultraviolet rays, X-rays, electron beams, ion beams, molecular beams, γ-rays, laser beams, etc. may be used, and particularly preferred radiation sensitivity The following substances can be mentioned.

(81 Quinonediazide compounds such as benzoquinonediazide sulfonic acid ester, naphthoquinonediazide sulfonic acid ester, benzoquinonediazide sulfonic acid amide, naphthoquinonediazide sulfonic acid amide, etc., and known quinonediazide compounds can be used as they are.More specifically, J
, by Kosar” Light-3intensive
Systems” 339-3352. (1965
LJohn Wtley & 5ons Company CNew Y
Ork), W, S, 口eFores, author ``Pho
toresist” 50. (1975), Me G
quinonediazide compounds described by RawHi)+ Inc., (New York). That is, 1,2-penzoquinonediazide-4-sulfonic acid phenyl ester, di(11,2''-benzoquinonediazide-42-sulfonyl)-4,4'-dihydroxybiphenyl, 1,2-benzoquinonediazide-4-
(N-ethyl-N-β-naphthyl)-sulfonamide,
1,2-naphthoquinonediazide-5-sulfonic acid cyclohexyl ester, 1-(1',2'-naphthoquinonediazide-5-sulfonyl)-3,5-dimethylpyrazole, 1,2-naphthoquinonediazide-5-sulfonic acid- 4'-Hydroxydiphenyl-4'-azo-β-naphthol ester, N,N-di(1,2-naphthoquinonediazide-5-sulfonyl)-aniline, 2-(1°
, 2°-naphthoquinonediazide-5°-sulfonyloxy)-1-hydroxy-anthraquinone, condensate of 2 moles of 1.2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mole of 4.4°-diaminobenzophenone, 1 .A condensate of 2 moles of 2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mole of 4.4°-dihydroxy-1,1゛-diphenylsulfone, and 1 mole of 1,2-naphthoquinonediazide-5-sulfonic acid chloride. Examples include a condensate with 1 mol of purbrogalin, 1,2-naphthoquinonediazide-5-(N-dihydroabiethyl)sulfonamino, and the like.

Also, Japanese Patent Publication No. 37-1953, Publication No. 37-3627, Publication No. 37-13109, Publication No. 40-26126
Publication No. 40-3801, Publication No. 45-5,604
No. 45-27.345, No. 51-13,
No. 013, JP-A No. 48-96.575, No. 4
No. 8-63,802, No. 48-63.803, No. 5B-75,149, No. 58-17, 112
It is also possible to use quinonediazide compounds described in Japanese Patent Publication No. 59-165,053 and the like.

Furthermore, naphthoquinone-(1,2)-diazide-(2
)-ester of sulfonic acid chloride and novolac resin, ester of pyrogallol-acetone resin and naphthoquinonediazide sulfonic acid chloride described in U.S. Pat. No. 3,635,700, JP-A-55-76
．． No. 346, No. 56-1,044, and No. 56-1
．． Ester of polyhydroxyphenyl resin and naphthoquinonediazide sulfonic acid chloride described in each publication of No. 045, homopolymer of p-hydroxystyrene described in JP-A-50-113,305, or this and other A copolymer with a copolymerizable monomer is subjected to an ester reaction with naphthoquinonediazide sulfonic acid chloride, and a reaction between a polymer product of a styrene monomer and a phenol derivative and quinonediazide sulfonic acid described in Japanese Patent Publication No. 49-17481 Products such as esters of polyhydroxybenzophenone and naphthoquinonediazide sulfonic acid chloride can also be used. The blending ratio when using the quinonediazide compound is as follows:
Usually, it is 5 to 50 parts by weight, preferably 10 to 40 parts by weight.

(b) Diazo resins Suitable diazo resins include salts of condensates of p-diazodiphenylamine and formaldehyde or acetaldehyde, such as hexafluorophosphates, tetrafluoroborates, perchlorates or periodates. Diazo resin inorganic salts which are reaction products with said condensates, as described in U.S. Pat. No. 3,300,309;
Examples include diazo resin organic salts which are reaction products of the above condensates and sulfonic acids. The blending ratio when using these diazo resins is usually 2 to 30 parts by weight based on 100 parts by weight of the alkali-soluble resin in the resist composition.
Preferably it is 5 to 20 parts by weight.

(C1 Aromatic azide compounds or aromatic diazide compounds such as azidochalcones as described in JP-A-58-203438, diazidobenzalmethylcyclohexanones and azidocinnamylidene acetophenones, Journal of the Chemical Society of Japan ( 1112, 1708-17
14.1983), aromatic azide compounds and aromatic diazide compounds. When using these aromatic azide compounds or aromatic diazide compounds, the blending ratio is usually 1 to 40 parts by weight, preferably 2 to 35 parts by weight, based on 100 parts by weight of the alkali-soluble resin of the resist composition. be.

(dl poly (olefin sulfones) such as JP-A-5
Examples include poly(olefin sulfone) II such as poly(2-methylpentene-1-sulfone) and poly(butene-sulfone) as described in Japanese Patent No. 9-152.

When using these poly(olefin sulfone) resins, the blending ratio is 10 parts alkali-soluble resin in the resist composition.
It is usually 2 to 35 parts by weight, preferably 3 to 30 parts by weight relative to 0 parts by weight.

The above-mentioned various radiation-sensitive substances can be selected and used in combination. The resist composition of the present invention is prepared by mixing the above-mentioned alkali-soluble resin, fluorine-based surfactant, and radiation-sensitive substance in an organic solvent. used.

Furthermore, storage stabilizers, dyes, pigments, stimulants, adhesion aids, non-fluorinated surfactants, and the like can be added to the resist composition of the present invention, if necessary.

Furthermore, in order to improve the adhesion between the coating film of the resist composition of the present invention and a substrate such as a silicon oxide film, hexamethyldisilazane, chloromethylsilane, or the like can be applied to the coated substrate in advance.

Various methods can be used to apply the resist composition of the present invention, such as spin coating, roll coating, dip coating, spray coating, and blade coating. Obtainable.

Examples of the developer for developing the resist coating film formed by the resist composition of the present invention include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia. , primary amines such as ethylamine and n-propylamine, tertiary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine, and alcohols such as dimethylethanolamine and triethanolamine. Amines, quaternary ammonium salts such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, or pyrrole, piperidine, 1,8-diazabicyclo[5.4.0]-7-undecene, 1.5-diazabicyclo[4]・An alkali solution of cyclic amines such as 3.0]-5-nothine, generally an aqueous solution is used,
When manufacturing integrated circuits where the use of metal-containing developers is a problem, it is preferable to use solutions of quaternary ammonium salts or cyclic amines. In addition, a solution obtained by adding an appropriate amount of a surfactant to the above alkali solution can also be used as a developer.Furthermore, when using the above aqueous alkali solution, a water-soluble organic solvent such as methanol or ethanol may be added. You can also do it.

〔Example〕

Examples of the present invention will be described below, but the present invention is not limited thereto.

Example 1 2.3.4-) 26.5 g of a condensate of lyhydroxybenzophenone and 0-naphthoquinonediazide-5-sulfonyl chloride, and 100 g of a novolac resin obtained by condensing cresol and formaldehyde were mixed with methyl cellosolve. A solution was prepared by dissolving it in 336 g of acetate, and a fluorine-based surfactant "S-382J (manufactured by Asahi Glass) was added thereto at a concentration of 5 pp- based on the solid content in the solution to prepare a resist composition. .

This resist composition was applied onto a silicon wafer with a diameter of 4 inches by spin coating at a rotation speed of 3.000 rpm.
After coating, the resist film was dried by heating for 25 minutes in an air circulation type open chamber kept at 90° C. to obtain a silicon wafer having a resist film with a thickness of 1.5 μm. The silicon wafer used here has a 0.7 μm thick silicon dioxide film formed by thermal oxidation on its surface.

Evaluation tests were conducted on the silicon wafer having a resist film (hereinafter referred to as "sample") obtained as described above with respect to the following items. The result is the first
Shown in the table.

(1) The resist film surface of the striation sample was examined using an optical microscope at a magnification of 1
Observation was made at 00x magnification to examine the occurrence of striations. The evaluation is expressed as "O" if no striation is observed, "Δ" if it is slightly observed, and "x" if it is clearly observed.

Furthermore, the surface roughness of the resist film was measured using a surface roughness meter "Kristetsub" (manufactured by Rank Taylor Hopson).

(2) Residual coating (wettability) The resist film surface of the sample was visually observed to determine whether there was any residual coating. The evaluation is expressed as "O" if no unpainted residue occurred, "Δ" if it occurred in a small part of the periphery of the sample, and "×" if it occurred in a part of the periphery of the sample. .

(3) Side etching (wet etching resistance) sample with contact aligner rPLA501FJ
(manufactured by Canon), was exposed to ultraviolet light through a mask with a line width of 2 μm, developed for 60 seconds using a 2.4% by weight aqueous solution of tetramethylammonium hydroxide, and then exposed for 20 seconds under running water. After rinsing and obtaining a resist pattern with a line width of 2 μm, the sample on which this resist pattern had been formed was post-baked for 30 minutes in an air circulating open tank maintained at 130°C, and then treated with a 49% by weight hydrogen fluoride aqueous solution/ 40% by weight ammonium fluoride aqueous solution (
Etching was carried out for 6 minutes using an etchant consisting of 1/1 weight ratio, and the resist pattern was peeled off. Side etch was measured for the etched portion of the wafer thus obtained. As shown in FIG. 1, the side etch is defined as the width A at the top surface of the pattern section 1 formed by etching the silicon dioxide film, and the width A at the bottom surface of the pattern section 1 (the boundary between the silicon dioxide film and the silicon layer 2). surface)
When the width at is B, it is obtained by the following equation.

-A Side etch-□ (μm) Examples 2 to 19, Comparative Examples 1 to 7 Table 1 shows the type and amount of fluorosurfactant and the organic solvent used to prepare the resist composition. A resist composition was prepared in the same manner as in Example 1, except that the resist composition was used to form a resist film on a silicon wafer in the same manner as in Example 1, and a total of 18 types of samples were prepared. Obtained.

In addition, as a comparative example, a resist composition was prepared in the same manner as in Examples 1 to 19 except that no fluorine-based surfactant was used for each organic solvent. A resist film was formed on the wafer, and a total of H1 samples were obtained. Evaluation tests were conducted on the same items as described in Example 1 for each of these 25 samples. The results are shown in Table 1.

Example 20 9 g of a novolak resin obtained by condensing 1 g of poly(2-methyl-1-pentene) sulfone, cresol (equal mixture of m-cresol and p-cresol), and formaldehyde was dissolved in 60 g of isoamyl acetate. A resist composition was prepared by adding a fluorine-based surfactant rS-382J (manufactured by Asahi Glass Co., Ltd.) to the solution at a concentration of 10 pp- based on the solid content in the solution.

This resist composition was applied onto a silicon wafer with a thermally oxidized film in the same manner as in Example 1 so that the film thickness after drying was 1 μm. When this sample was observed for the presence or absence of striations, no striations were observed, and 40 mackerel had rough surfaces.

〔Effect of the invention〕

The resist composition of the present invention contains a specific organic solvent and a fluorosurfactant, and has the following effects.

(1) When forming a coating film by spin coating, it is possible to form a resist film that has excellent coating properties such as almost no striations and has an extremely smooth surface.

(2) The resist 11 composition has good wettability with respect to the substrate, and does not leave any unpainted area, making it possible to form a uniform and complete resist film.

(3) To form a resist film that has good adhesion to the substrate, is resistant to side etching phenomenon, that is, a phenomenon in which etchant permeates under the resist pattern area and is etched, and has excellent wet etching resistance. I can do it.

Since the resist composition of the present invention has the above-mentioned characteristics, it is possible to achieve highly accurate lamination lithography.
For example, it can be suitably used as a resist used in the manufacture of semiconductor integrated circuits, printed circuit boards, television shadow masks, optical integrated circuits, and the like.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a method for measuring side etching in an example.

Claims (1)

[Scope of Claims] 1) (a) an alkali-soluble resin, (b) at least one member selected from methyl cellosolve acetate, diglyme, cyclopentanone, cyclic lactone, alkylene carbonate, acetic acid alkyl ester, and monooxymonocarboxylic acid ester 1. A resist composition comprising: (c) a fluorine-based surfactant; and (d) a radiation-sensitive substance.