JPS61226746A - Radiation sensitive composition - Google Patents

Abstract

PURPOSE:To form a coat film uniform in thickness by incorporating an acrylate type polymer having alkyl groups and fluoroalkyl groups on the side chains and/or such a methacrylate type polymer. CONSTITUTION:The (meth)acrylate type polymer to be used has alkyl groups and fluoroalkyl groups on the side chains and a number average mol.wt. of <=30,000 in terms of the standard polystyrene, and usually, an F-content of 5-80wt%, and it is prepared by copolymerizing a (meth)acrylate monomer having an alkyl group with a (meth)acrylate monomer having a fluoroalkyl group. The polymer is used in an amt. of 0.0001-2wt% of the total solid components of the radiation sensitive compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a radiation-sensitive composition, which is improved in that it can form a uniform coating film with no uneven coating, and
The present invention relates to a radiation-sensitive composition suitable as a resist for microfabrication used, for example, in the manufacture of semiconductor integrated circuits.

[Conventional technology]

In the manufacture of semiconductors, semiconductor integrated circuits, etc. using various phosphorography techniques, in order to form highly accurate fine resist patterns that faithfully reproduce the mask, resist compositions are required to have sensitive characteristics to radiation such as resolution and sensitivity. It is required not only to be excellent in terms of the following, but also to be able to form a coating film having a uniform thickness without coating unevenness.

However, conventional resist compositions have a problem of causing coating unevenness called striation. This striation is a coating unevenness 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 is usually a wave-like undulation with a height difference of several hundred λ. is doing.

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, in recent years, substrates such as silicon wafers have tended to have large diameters, which causes a problem in that uncoated areas tend to occur when a resist composition is applied onto a substrate.

[Problems to be Solved by the Invention and Problem 5] The present invention solves the problem of conventional radiation-sensitive compositions, which tend to cause coating unevenness such as striations, and has good turbidity on the substrate. The object of the present invention is to provide a radiation-sensitive composition suitable as a resist, which can form a film having a uniform thickness without any residual coating, and can achieve highly accurate microfabrication.

[Means for solving problems]

The above problem can be solved by using acrylate polymers and/or methacrylate polymers (hereinafter simply "(meth)acrylate 1
The present invention is solved by a radiation-sensitive composition characterized in that it contains a compound (hereinafter referred to as "coalescence").

That is, one aspect of the present invention is that the radiation Im! In a radiation-sensitive composition formed by dissolving a IIi-responsive substance in a solvent together with a binder and other additives added as necessary, #& additives having a specific group in the side chain (meth) It is characterized by the use of acrylate polymer.

Hereinafter, one aspect of the present invention will be explained in detail.

As the (meth)acrylate electrolyte in the present invention,
aa has an alkyl group and an alkyl heptadide Xt-, and further has a standard polystyrene equivalent number average molecular weight of preferably 3
0,000 or less, more preferably 2,000 to 30,
A value in the range of 000 is used. The number average molecular plate of (meth)acrylate polymer is 30. If it exceeds OOO't', the viscosity of the composition will increase and the coating properties will be insufficient.

As the acrylate structural unit or methacrylate structural unit having an alkyl group in the side chain in the above (meth)acrylate polymer, for example, the following general formula % formula % (wherein R is a hydrogen atom or a methyl group, and n is 1 to
22 integer gold is shown. ), specifically, Nayama 3 o-c2as α(3H
7Q-13CH3G (3 0C7H1s 0-c881?
In addition, as the acrylate structural unit or methacrylate structural unit having a fluorinated alkyl group in the side chain in the (meth)acrylate polymer, for example, the following general formula % formula % (in the formula , R is a hydrogen atom or a methyl group, and n is θ~
Indicates an integer of 20. ) or the following general formula -CH2-C- (wherein, R is a hydrogen atom or a methyl group, and n is 1 to
IO is an integer, and m is an integer from θ to 20. ), and specific examples include C=00-CH2(CF2)2CF3.In addition, the above (meth)acrylate and polymer have a fullylene oxide group in the side chain. , an acrylate structural unit or a methacrylate structural unit having an aryl group, an arylene group, etc., such as the following general formula R -CH2-C- C=0 0- (Cn HZ n O) m H (wherein, R is a hydrogen atom or is a methyl group, n is an integer of 1 to 6, m
represents an integer from 1 to 1o. ), specifically 0-C4H8()1(0-(C2H40)29-CH2
-CH--Gh-CH- etc., and -Cki2-CH--CHz-C)i-(:=□
c=.

It may have a structural unit represented by the following.

Furthermore, the methacrylate polymer used in the present invention is
Structural units other than the above, such as -CH2-CH--CH? CH- R -CF2-CF)i-, -CF2-CF2-, -C
H2-CM-.

OOH It may also have the following.

Note that the fluorine content of the (meth)acrylate polymer in the present invention is usually 5 to 80 wt*, preferably 8 to 6
It is 5 layers 1*.

Such a (meth)acrylate polymer can be obtained, for example, by copolymerizing an acrylate monomer or methacrylate monomer having an alkyl group and an acrylate monomer or methacrylate monomer having a fluorinated alkyl group.

The (meth)acrylate polymer used in the present invention is commercially available as a fluorosurfactant, and specific examples include "8C-1014,""5c-102,""5C-
103'' and ``5C-1044 (both manufactured by Asahi Glass ■).

The (meth)acrylate polymer in the present invention is 0.0001 to 0.0001 to the solid content constituting the radiation sensitive composition.
It is desirable to use it in a proportion of 1% by weight, preferably 0.0005 to 1% by weight. Usage rate is 0.000
If the amount is less than 1% by weight, the effect of preventing striation is insufficient, and if the amount used exceeds 2% by weight, the softening temperature of the composition will be lowered.

The radiation-sensitive substance constituting the radiation-sensitive composition of the present invention includes radiation such as ultraviolet rays, far-ultraviolet wind X-rays, electron beams,
Any substance whose solubility in a developer changes upon irradiation with ion beams, molecular beams, r-rays, etc. (particularly preferred radiation-sensitive substances include the following.

Quinonediazide compounds such as benzoquinonediazide sulfonic acid ester, naphthoquinonediazide sulfonic acid ester, benzoquinonediazide sulfonic acid amide, and naphthoquinonediazide sulfonic acid amide, and known quinonediazide compounds can be used as they are. Furthermore, the specific busyness is J,
Written by KosBr” Lj ght-8en S 1 t
I Ve sy S t eml! ” 3
39=3352*(1965), John Wile
y & 5ons (New York), W.
Written by S @ De Forest +1 photo
oreaist” 5 (L (1975), Mc Gr.
and quinonediazide compounds described by aW Hill, Inc. (New York). That is, 1,2-benzoquinonediazide-4-sulfonic acid phenyl ester, cy++ (l II.

2 II-/<Nzoquinonediazide-41-sulfonyl)-4,400-dihydroxybiphenyl, 1,2-benzoquinonediazide-4-(N-ethyl-N-, SL7thyl)-sulfonamide, 192- thia) quinonediazide-5-sulfonic acid cyclohexyl ester, 1-(
11,2'-naphthoquinonediazide-51-sulfonyl)-3,s-dimethylpyrazole, 1,2-7toquinonediazide-5-sulfonic acid-4f-hydroxydiphenyl-41+-azo-β-naphthol ester, N, N
-di(l,2-su7toquinonediazide-5-sulfonyl)-aniline, 2-(lf,2'-naphthoquinonediazide-51-sulfonyloxy)-1-hydroxy-anthraquinone, 1,2-naphthoquinonediazide-5 - Condensation product of 2 moles of sulfonic acid chloride and 1 mole of 4゜41-diaminobenzophenone, 2 moles of 1.2-su7toquinonediazide 5-sulfonic acid chloride and 1 mole of 4.4+-dihydroxy-1゜31-diphenylsulfone Molto-condensate, 1
．． Examples include 2-su7toquinone diazide 5-(N-dihydroabiethyl)-sulfonamino.

Also, Japanese Patent Publication No. 37-1953, Publication No. 37-3627, Publication No. 37-13109, Publication No. 40-26326
- No. 40-3801, No. 45-5604
No. 45-27345, No. 51=1301
Publication No. 3, JP-A-48-96575, JP-A-48-6
Publication No. 3802, Publication No. 48-63803, Japanese Unexamined Patent Publication No. 1973
Quinonediazide compounds described in US Pat. No. 8-75149, US Pat. No. 58-17112, US Pat. 1,2)-Diazido-(2)-sulfonic acid chloride esters with 7-enol or cresol-formaldehyde resins, esters of pyrogallol-acetone resins and naphthoquinonediazide sulfonic acid chlorides as described in U.S. Pat. No. 3,635,700. , esters of polyhydroxyphenyl resin and naphthoquinonediazide sulfonic acid chloride described in JP-A-55-76346, JP-A-56-1044, and JP-A-56-1045, JP-A-50-113305 A product prepared by subjecting a homopolymer of p-hydroxystyrene or a copolymer thereof with other copolymerizable monomers to an ester reaction with naphthoquinonediazide sulfonic acid chloride, as described in Japanese Patent Publication No. 17481-1981
The reaction product of a polymer product of a styrene monomer and a phenol derivative and quinonediazide sulfonic acid, the ester of polyhydroxybenzophenone and naphthoquinonediazide sulfonic acid chloride, etc. described in the above publication can also be used.

Such a 7-toquinone diazide compound is used together with a binder if necessary. Suitable binders include novolak resins that are soluble in alkaline aqueous solutions. As for such Novolak m7J,
Phenol-formaldehyde 2-ink resin, cresol-formaldehyde novolac resin, p-tert
Typical examples include -butylphenol-formaldehyde novolac resin. -The blending ratio of the medium nondiazide compound in the entire composition is usually 1
0 to 50% by weight, preferably 20 to 40% by weight 1*. Further, the blending ratio of the binder is usually 45 to 80% by weight and 11% by weight of the total composition, preferably 50 to 70% by weight.
It's heavy duty.

Diazo resins Suitable diazo resins include salts of condensates of p-diazodiphenylamine and formaldehyde or acetaldehyde, such as hexafluorophosphates, tetrafluoroborates, perchlorates or periodates. Examples include diazo resin inorganic salts which are the reaction products of the above-mentioned conjugates and the sulfonic acids, and diazo resin organic salts which are the reaction products of the conjugates and sulfonic acids as described in US Pat. No. 3,300,309. It will be done.

These diazo resins are preferably used together with a binder. Various polymeric compounds can be used as such a binder, but preferably aromatic hydroxyl-based monomers such as those described in JP-A-54-98613, such as N-(4 -hydroxyphenyl)acrylamide, N-(4-hydroxyphenyl)methacrylamide)", o-.

Copolymers of m- or p-hydroxystyrene, o-, m- or p-hydroxyphenyl methacrylic acid donor with other monomers, hydroxy as described in U.S. Pat. No. 4,123,276. Polymers containing ethyl acrylate units or hydroxyethyl methacrylate units as the main repeating unit, natural resins such as shellac and rosin, polyvinyl alcohol, U.S. Pat.
751,257, linear polyurethane resins as described in U.S. Pat. No. 3,660,097, phthalated resins of polyvinyl alcohol, epoxy resins condensed from bisphenol A and epichlorohydrin, cellulose to cellulose acetate. Included are celluloses such as acetate 7-talate.

(-CH=C as a photosensitive group in the main chain or side chain of the polymer)
Radiation-sensitive resins such as H-C-1-containing polyesters, polyamides, and polycarbonates, such as those described in JP-A No. 55-404]5,
Photosensitive polyester obtained by condensation of phenylene diethyl acrylate with hydrogenated bisphenol A and triethylene glycol, US Pat. No. 2,956,878
Photosensitive polyesters derived from (2-probeliden) malonic acid compounds such as cinnamylidene malonic acid and difunctional glycols, etc., which are described in the specification of the above patent, can be mentioned.

(Φ Aromatic azide compounds or aromatic azide sulfonyl compounds such as azidochalcones, diazidobenzalmethyl microhexanones, and/or azidocinnamylidene acetophenone described in JP-A-58-203438) and a p-vinylphenol polymer and/or a novolak resin,
Journal of the Chemical Society of Japan, Nθ12 p1708-1714 19
Aromatic azide compounds described in 1983, and/
Alternatively, a photosensitive composition comprising an aromatic diazide compound and an 0-vinylphenol polymer may be mentioned.

(e) Poly(olefin sulfones) such as poly(2-
Examples include radiation-sensitive compositions consisting of poly(olefin sulfones) such as methylpentene-1-sulfone] and poly(butene sulfone), and novolac resins containing m-cresol and p-cresol as main components. .

The radiation-sensitive composition of the present invention can be obtained by dissolving the above components in an organic solvent.

Examples of organic solvents used in this case include glycol ethers such as ethyl glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol diptyl ether, and diethylene glycol dimethyl ether, methyl cellosolve acetate, and ethyl cellosolve acetate. , cellosolve esters such as butyl cellosolve acetate, aromatic hydrocarbons such as toluene and xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 5/clopentanone, acetonyl acetone,
Ketones such as acetophenone and isophoronato, ethers such as benzyl ethyl ether, 1゜2-dibutoxyethane and dihexyl ether, fatty acids such as caproic acid and caprylic acid, 1-octatool, 1-nonanol,
1-decanol, benzyl alcohol nato alcohols, ethyl acetate, butyl acetate, 2-ethylhexyl acetate, benzyl acetate, benzyl benzoate, diethyl oxalate, diptyl oxalate, diethyl malonate, dimethyl maleate, diethyl maleate, diptyl maleate , esters such as dimethyl phthalate, ethylene carbonate, propylene carbonate, and cyclic lactones such as r-butyrolactone. These organic solvents may be used alone or in combination of two or more.

The amount of this organic solvent used varies depending on the required film thickness when applying the composition solution, but in general, the amount of the composition 100!
[100 to 2,000 parts by weight, preferably 300 to 1,500 parts by weight, based on parts of ffi.

Various methods can be used to apply the radiation-sensitive composition of the present invention, such as spin coating, roll coating, dip coating, spray coating, and blade coating. You can get the full effect of

〔·Example〕

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

Example 2 I 3e 4-) 'J 26.5 g of a condensate of hydroxybenzophenone and 0-naphthoquinonediazide-5-sulfonyl chloride and 100 g of cresol-formaldehyde novolac resin were dissolved in 336 g of cellosolve acetate to form a solution. A resist solution was prepared by adding this K (meth)acrylate polymer "5c-101J (manufactured by Asahi Glass Co., Ltd.) at a concentration of sppm to the solid content. This resist solution was applied to a silicon wafer with a diameter of 4 inches. After coating by spin coating at a rotation speed of 3.0QQrpm, it was coated in an air circulating oven kept at 90°C for 2 hours.
It was dried by heating for 5 minutes to obtain a silicon wafer having a resist film with a film thickness of 1.5 μm.

Note that the silicon wafer used here has one surface with
It has a silicon dioxide film with a thickness of 0.7 μm formed by thermal acidification.

The silicon wafer (hereinafter referred to as "sample") having a resist film obtained as described above was evaluated with respect to the following items. The results are shown in Table 1.

0) The resist film surface of the striation sample was magnified by 4N using an optical microscope.
Observation was made at a magnification of 0.0 magnification to examine the state of striae formation. The evaluation is as follows: t rOJ where the occurrence of IJ anyon is not observed, "Δ" where it is slightly observed, and 't' rxJ where it is clearly observed.

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

Q) Remaining coating (wettability) The resist film surface of the sample was examined using an optical microscope at a magnification of 1.
Observation was made at a magnification of 0.00 to check for the occurrence of unpainted areas. The evaluation is expressed as 'trOJ' if no unpainted residue occurred, 'Δ' if it occurred in a small part of the periphery of the sample, and 'x' if it occurred in a part of the periphery of the sample. .

0) Side etching (wet etching resistance) Sample with contact aligner-1” PLA501FJ
(manufactured by Canon Corporation) and exposed to ultraviolet rays through a mask with a line width of 2 μm.

Incubate for 60 seconds using a 2.4 wt s aqueous solution of tetramethylammonium hydroxide, rinse for 20 seconds under running water,
A resist pattern with a line width of 2 μm was obtained.

Next sample with this resist pattern formed? 13
After post-baking for 30 minutes in an air-circulation type open air chamber maintained at 0CK, a 49-tS fuf hydrogen aqueous solution/40
Ammonium fluoride aqueous solution of heavy ILLs (superposition ratio 1:1
) After etching for 6 minutes using an etchant, the resist pattern was peeled off. Side etch was measured for the etched portion of the wafer thus obtained. In the side etching, as shown in FIG. When the width at the plane) is 7B, it is obtained by the following formula.

-A side etch = (μm) Examples 2 to 16 Type of (meth)acrylate polymer and addition tt - A resist solution was prepared in the same manner as in Example 1, except that it was as shown in Table 1, and A resist film was formed on a silicon wafer using this resist solution, and a total of 15 types of samples were obtained. For each of these 15 samples,
An evaluation test was conducted on the same items as described in Example. The results are shown in Table 1.

Comparative Example 1 (A resist solution was prepared in the same manner as in Example 1 except that no metacoacrylate polymer was added, and a resist film was formed on a silicon wafer using this resist solution to obtain a comparative sample.

This sample was evaluated with respect to the same items as described in Example 1. The results are shown in Table 1.

As is clear from the above results, the example of the present invention was superior in all items compared to the comparative example in which no (meth)acrylate polymer was added. The effect has been confirmed. α) When forming a coating film by spin coating, there is almost no striation, and a resist film with an extremely smooth surface can be formed.

(2) The wettability of the resist solution to the substrate (silicon wafer S) is good, and a uniform and complete resist film can be formed without leaving any unpainted areas.

6) It is possible to form a resist film that has good adhesion to the substrate and has excellent wet etching resistance without causing the side etching phenomenon, that is, the phenomenon in which etchant penetrates under the resist pattern area and causes etching. can.

〔Effect of the invention〕

The radiation-sensitive composition of the present invention contains a specific (meth)acrylate polymer and has the following effects.

0) Less likely to cause uneven coating such as striations (,
It is possible to form a coating film with a smooth and uniform thickness (It has excellent wettability to the two substrates, and can form a coating film in a perfect state with no leftover coating.

0) The radiation-sensitive composition of the present invention has the above-mentioned characteristics. Therefore, highly accurate phosphorography can be achieved, and it can be suitably used as a resist used, for example, in the manufacture of semiconductor integrated circuits, printed circuit boards, television shadow masks, optical integrated circuits, etc.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view schematically showing an etched silicon wafer.

Claims (1)

[Claims] 1) A radiation-sensitive composition containing an acrylate polymer and/or a methacrylate polymer having an alkyl group and a fluorinated alkyl group in the side chain.