JP3132622B2 - Positive photoresist composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a novel positive photoresist composition, and more particularly, to a high resolution, high sensitivity, high heat resistance, and a focus even on a substrate having irregularities or a substrate having a high reflectance. The present invention relates to a positive photoresist composition having excellent depth width characteristics, exposure latitude characteristics, and ability to form an ultrafine pattern of half a micron or less.

[0002]

2. Description of the Related Art Conventionally, as a photoresist in a process of manufacturing a semiconductor device such as an IC or an LSI or a liquid crystal device such as an LCD, a positive electrode comprising a combination of an alkali-soluble resin for forming a film and a photosensitive component comprising a compound containing a quinonediazide group is used. Type photoresist compositions are known to be suitable and have been put to practical use. As an alkali-soluble resin for forming a film, it can be dissolved in an alkali aqueous solution as a developing solution without swelling and has excellent developing characteristics, and also has excellent resistance to plasma etching as a mask at the time of etching. Novolak is useful from the point of view.

[0003] The quinonediazide group-containing compound as a photosensitive component has an effect of suppressing the alkali solubility of novolak itself, but has a function of suppressing electromagnetic waves such as ultraviolet rays (g-rays and i-rays) and far ultraviolet rays including excimer lasers. It is unique in that when it receives irradiation or drawing of a particle beam such as an electron beam, it changes to alkali-soluble and has an action of promoting the alkali-solubility of novolak. As described above, many positive photoresist compositions containing a quinonediazide group-containing compound having a large property change by receiving radiation such as electromagnetic waves and particle beams and an alkali-soluble novolak have been developed and put into practical use (for example, US Pat. No. 4377631, JP-A-62-35349
JP, JP-A-1-142548, JP-A-1-1-1
No. 79147, Japanese Patent Publication No. 3-4897).

However, in recent years, the degree of integration of semiconductor devices and liquid crystal devices has been increasing more and more, and in the production of VLSI and the like, processing of ultrafine patterns of submicron (1.0 μm or less) and half micron (0.5 μm) or less. Because high accuracy is required, the characteristics required for the positive photoresist composition to be used include high resolution,
Excellent cross-sectional shape, heating operation after dry etching or irradiation, and before development (PEB; Post Exp)
osure bake), it is possible to form a resist pattern excellent in heat resistance that does not cause thermal deformation, high sensitivity in terms of high productivity, and a resist pattern that is faithful to the mask pattern without being affected by substrate steps. It has excellent focal depth width characteristics for reproducibility, other excellent halation prevention effects, and a sufficient exposure margin.

In response to such demands for improvement in various resist properties, researches focusing on the development of photosensitive components, particularly new photosensitive components that can replace conventional polyhydroxybenzophenones, have been actively conducted in recent years. It has become. Particularly recently, various positive resist compositions containing a specific tris (hydroxyphenyl) methane-based compound as a novel photosensitive component have been recently proposed (JP-A-1-18996).
44, JP-A-3-158856, JP-A-4
-284454, JP-A-4-293050, JP-A-4-301850, JP-A-4-328
555, JP-A-5-181270, JP-A-5-188590, JP-A-5-204144, etc.).

However, for example, Japanese Patent Application Laid-Open No. H3-1588
Although tris (4-hydroxyphenyl) methane exemplified in Japanese Patent No. 56 is excellent in sensitivity, it has a narrow depth of focus and is insufficient in heat resistance and resolution. Also, JP-A-4-284454, JP-A-4-301850
JP-A-5-181270 and JP-A-5-181270
Compounds of the following formula exemplified in JP-A-188590

Embedded image as well as

Embedded image Are highly sensitive and have a resolution of 0.35 to 0.45.
Although it shows a considerable resolution of μm, it is inferior in the depth of focus characteristic. Further, compounds of the following formulas exemplified in JP-A-4-328555

Embedded image Shows good heat resistance, but has a resolution of 0.6 to 0.1.
Since the exposure margin is narrow, the line width changes greatly with respect to the exposure energy, so that it is difficult to apply to ultra-miniaturization of half a micron or less.

As described above, the above-mentioned novel photosensitive components exhibit relatively good characteristics in resolution, sensitivity, heat resistance, etc., respectively. However, various resists required for the current ultrafine processing resist composition as described above are required. It was difficult to satisfy all the resist characteristics at the same time. In particular, the rapid increase in the degree of integration of semiconductor integrated circuits in recent years has been remarkable, and there is a strong demand for an improvement in the resolution associated therewith.
It is said that a design rule of 0.35 μm is required for 64M-DRAM after the DRAM.

To meet such required characteristics, from the viewpoint of an exposure apparatus, there is a direction in which the resolution is expected to be improved by increasing the numerical aperture of a lens. There is a problem that the width becomes narrow and it is difficult to apply it to a resist surface having a large step. As described above, at present, the conventional positive photoresist composition cannot sufficiently cope with various resist characteristics currently required.

[0009]

SUMMARY OF THE INVENTION Under these circumstances, the present invention provides a high-resolution, excellent cross-sectional shape and excellent heat resistance suitable for forming ultra-fine patterns of 64M-DRAM and thereafter. Resist pattern with high sensitivity,
In addition, the object of the present invention is to provide a positive photoresist composition having a depth of focus characteristic and a sufficient exposure margin.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a positive photoresist composition having the above-mentioned preferable properties, and have found that an alkali-soluble resin and a specific photosensitive component are used. As a result, the present inventors have found that the object can be achieved, and have completed the present invention based on this finding.

That is, the present invention provides a positive photoresist composition containing an alkali-soluble resin and a photosensitive component, wherein the photosensitive component is represented by the general formula (I):

Embedded image (Where k, l and m are an integer of 0 or 1 to 3, and n is 1 or 2) quinonediazide sulfonic acid ester of at least one aromatic polyhydroxy compound selected from the compounds represented by the following formulas: Having an esterification rate of 50
% And a diester content of 60% or more on a molar basis, and a compound represented by the general formula (II):

Embedded image (Wherein R ^{1 to} R ⁶ are a hydrogen atom, a halogen atom, a hydroxyl group,
An alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, R ⁷ and R ^{8 each} represent a hydrogen atom, a halogen atom or
To 4 alkyl groups, R ⁹ is a hydrogen atom or a methyl group,
R ¹⁰ and R ¹¹ are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), and a compound represented by the general formula (III):

Embedded image (In the formula, R ¹¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ^{12 to} R ¹⁷ are a hydrogen atom, a halogen atom,
At least one selected from a compound represented by the formula:
Quinonediazidosulfonic acid esters of an aromatic polyhydroxy compound, wherein the esterification rate is 50% or more;
An object of the present invention is to provide a positive photoresist composition characterized by being a mixture with a compound having a triester content of 85% or more on a molar basis.

In the positive photoresist composition of the present invention, an alkali-soluble resin is used as a film-forming substance. There is no particular limitation on the alkali-soluble resin, and alkali-soluble resins conventionally used as a film-forming substance in conventional positive photoresist compositions, for example, aromatic hydroxy compounds such as phenol, cresol and xylenol, and aldehydes such as formaldehyde Alternatively, a condensation reaction product with a ketone such as acetone, polyhydroxystyrene, a derivative thereof, and the like can be given.

Examples of the aromatic hydroxy compound include phenol, m-cresol, p-cresol, o-cresol, 2,3-xylenol, 2,5-xylenol, 3,5-xylenol, and 3,4-xylenol. Xylenols, m-ethylphenol, p-ethylphenol, o-ethylphenol, 2,3,5-trimethylphenol, 2,3,5-triethylphenol, 4-tert-butylphenol, 3-tert-
Butylphenol, 2-tert-butylphenol,
2-tert-butyl-4-methylphenol, 2-t
alkylphenols such as tert-butyl-5-methylphenol, alkoxyphenols such as p-methoxyphenol, m-methoxyphenol, p-ethoxyphenol, m-ethoxyphenol, p-propoxyphenol and m-propoxyphenol, o- Isopropenylphenol, p-isopropenylphenol,
2-Methyl-4-isopropenylphenol, isopropenylphenols such as 2-ethyl-4-isopropenylphenol, arylphenols such as phenylphenol, 4,4'-dihydroxybiphenyl, bisphenol A, resorcinol, hydroquinone, pyrogallol And the like. These may be used alone or 2
A combination of more than one species may be used. Among these aromatic hydroxy compounds, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, and 2,3,5-trimethylphenol are particularly preferable.

The aldehydes include, for example, formaldehyde, paraformaldehyde, trioxane,
Acetaldehyde, propionaldehyde, butyraldehyde, trimethylacetaldehyde, acrolein,
Crotonaldehyde, cyclohexanealdehyde, furfural, furylacrolein, benzaldehyde, terephthalaldehyde, phenylacetaldehyde, α-
Phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-
Chlorobenzaldehyde, cinnamic aldehyde and the like can be mentioned. These may be used alone or in combination of two or more. Among these aldehydes, formaldehyde is preferred from the viewpoint of availability, and hydroxybenzaldehyde is particularly preferred for improving heat resistance.

Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone and diphenyl ketone. These may be used alone or in combination of two or more. In a combination of an aromatic hydroxy compound and a ketone, that of pyrogallol and acetone is preferred.

The condensation reaction product of the aromatic hydroxy compound and the aldehyde or ketone can be produced by a known method in the presence of an acidic catalyst. Hydrochloric acid, sulfuric acid, formic acid, acetic acid, oxalic acid, p-toluenesulfonic acid and the like can be used as the acidic catalyst at that time. The condensation product obtained in this manner is preferably one obtained by cutting a low-molecular-weight region by subjecting it to a treatment such as fractionation, because it has excellent heat resistance. Treatment such as fractionation, the resin obtained by the condensation reaction is a good solvent, for example, methyl alcohol,
It is carried out by a method of dissolving in alcohol such as ethyl alcohol, ketone such as acetone or methyl ethyl ketone, ethylene glycol monoethyl ether acetate, tetrahydrofuran, etc., and then pouring into water to precipitate. The preferred weight average molecular weight of the condensation reaction product is 2
000-25000, preferably 2500-20000
Is selected in the range. Here, the weight average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography.

Examples of the polyhydroxystyrene and its derivative include a homopolymer of vinylphenol and a copolymer of vinylphenol and a comonomer copolymerizable therewith. Examples of the comonomer include acrylic acid derivatives, acrylonitrile, methacrylic acid derivatives, methacrylonitrile, styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene and p-methylstyrene.
Styrene derivatives such as methoxystyrene and p-chlorostyrene are exemplified.

In the composition of the present invention, a quinonediazidesulfonic acid ester of a specific aromatic polyhydroxy compound is used as a photosensitive component. As the specific aromatic polyhydroxy compound, a mixture of the compound of the general formula (I) and the compounds of the general formulas (II) and / or (III) is used.

Further, the ester has an esterification ratio of the aromatic polyhydroxy compound of 50% or more, preferably 60% or more, more preferably 80% or more, and the aromatic polyhydroxy compound of the general formula (I). , The diester content therein is at least 60%, preferably at least 70% on a molar basis, and for the aromatic polyhydroxy compound of the general formula (II) and / or (III), It is necessary that the content of the triester in the ester is 85% or more, preferably 90% or more on a molar basis. The esterification rate, diester content and triester content mean those determined by the following formulas.

[0020]

(Equation 1)

[0021]

(Equation 2)

[0022]

(Equation 3)

The term "total number of moles of the esterified product" means the total number of molecules (monoester, diester, triester, and possibly tetraester of an aromatic polyhydroxy compound) constituting the esterified product on a molar basis. It is.

The quinonediazide sulfonic acid includes
Benzoquinone-1,2-diazide-4-sulfonic acid, naphthoquinone-1,2-diazide-4-sulfonic acid, naphthoquinone-1,2-diazide-5-sulfonic acid, naphthoquinone-1,2-diazide-6-sulfone O-quinonediazidosulfonic acid such as naphthoquinone-1,2-diazidosulfonic acid, orthobenzoquinonediazidesulfonic acid, orthoanthraquinonediazidosulfonic acid such as acid, and particularly naphthoquinone-1,2-diazide-5-
Sulfonic acid is preferred.

When n = 2, the compound of the general formula (I) has the general formula (Ia)

Embedded image And when n = 1, the general formula (Ib)

Embedded image The compounds of the general formula (Ia) include, for example, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane, bis (5-cyclohexyl-4) -Hydroxy-2-methylphenyl) -3,5-dihydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2,4-dihydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy) -2-methylphenyl) -2,5-dihydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxyphenyl) -3,4-dihydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxy-5-methylphenylmethane, (5- Kurohekishiru -4-hydroxy-2
-Methylphenyl), (5'-cyclohexyl-4'-
(Hydroxyphenyl) -3,4-dihydroxyphenylmethane, etc., and bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane is particularly preferred.

Examples of the compound of the general formula (Ib) include bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy- 2-
Methylphenyl) -3-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxyphenyl)-
4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxyphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxy-4-methylphenylmethane, Bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-hydroxy-5
-Methylphenylmethane, (5-cyclohexyl-4-
Hydroxy-2-methylphenyl), (5'-cyclohexyl-4'-hydroxyphenyl) -2-hydroxyphenylmethane and the like, especially bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2
-Hydroxyphenylmethane is preferred.

The compound of the general formula (I) is, for example,

Embedded image Wherein m is 0 or an integer of 1 to 3, n is 1 or 2, and a compound represented by the general formula:

Embedded image (Where k is an integer of 0 or 1 to 3) in the presence of an acidic catalyst (see, for example,
No. 275955).

The compound of the above general formula (II) includes, for example,

Embedded image

Embedded image

Embedded image

Embedded image

Embedded image And the compound represented by the formula (IV) is particularly preferable.

The compound of the general formula (III) includes
For example, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-3,5-dimethylphenyl) -4-
Hydroxyphenylmethane, bis (4-hydroxy-
3,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4- Hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2
Tris (hydroxyphenyl) methanes such as -hydroxyphenylmethane and bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane.

The compound of the general formula (II) can be prepared by the same method as disclosed in, for example, JP-A-62-84035, by substituting a substituted or unsubstituted phenol with a substituted or unsubstituted benzaldehyde or alkyl. It is obtained by condensing phenyl ketones in the presence of an acidic catalyst.

The compound of the general formula (III) is, for example,

Embedded image (In the formula, R ¹¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ¹⁶ and R ¹⁷ are a hydrogen atom, a halogen atom, and 1 to 4 carbon atoms.
Which is an alkyl group having 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms) and a general formula

Embedded image (Wherein R ¹² and R ¹³ in the formula are a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms) by a condensation reaction in the presence of an acidic catalyst. can get.

The esterified product as a photosensitive component in the composition of the present invention is usually obtained by completely or partially esterifying a predetermined aromatic polyhydroxy compound with a corresponding quinonediazidesulfonic acid halide. This esterification reaction is carried out in a solvent usually used for this type of reaction, for example, dioxane, in the presence of a basic condensing agent such as triethanolamine, alkali carbonate or alkali hydrogen carbonate.

The preferred aromatic polyhydroxy compound used in this case is 2: 1 to 1: 3 based on the molar ratio of the compound of the formula (Ia) to the compound of the formula (Ib). Or 5: 1: 2 based on the molar ratio of the compound of the general formula (Ia) to the compound of the general formula (Ib) and the compound of the general formula (II) and / or the compound of the general formula (III).
Or a mixture in the vicinity.

In the present invention, other quinonediazide group-containing compounds such as orthobenzoquinonediazide, orthonaphthoquinonediazide, and orthoquinonediazide such as orthoanthraquinonediazide may be used as the photosensitive component, if necessary, as long as the object is not impaired. A reaction product of a sulfonic acid halide and a compound having a hydroxyl group or an amino group or the like can be used in combination. The compound having a hydroxyl group or an amino group includes the following (a) to (a)
The compound (d) is preferred.

(A) 2,3,4-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,
3,4,4'-tetrahydroxybenzophenone, 2,
2 ', 4,4'-tetrahydroxybenzophenone,
2,3 ', 4,4', 6-pentahydroxybenzophenone, 2,2 ', 3,4,4'-pentahydroxybenzophenone, 2,2', 3,4,5'-pentahydroxybenzophenone, 2, 3 ', 4,5,5'-pentahydroxybenzophenone, 2,3,3', 4,4 ',
Polyhydroxybenzophenones such as 5'-hexahydroxybenzophenone;

(B) bis (3-cyclohexyl-6-hydroxyphenyl) -3-hydroxyphenylmethane,
Bis (3-cyclohexyl-6-hydroxyphenyl)
-4-hydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxyphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl) -2-hydroxyphenylmethane, bis (5 -Cyclohexyl-2-hydroxy-
Bis (cyclohexylhydroxyphenyl) -hydroxyphenylmethanes such as 4-methylphenyl) -4-hydroxyphenylmethane.

(C) 2- (2,3,4-trihydroxyphenyl) -2- (2 ', 3', 4'-trihydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2 -(2 ', 4'-dihydroxyphenyl) propane, 2- (4-hydroxyphenyl) -2- (4'
-Hydroxyphenyl) propane, bis (2,3,4-
[(Poly) hydroxyphenyl] alkanes such as trihydroxyphenyl) methane and bis (2,4-dihydroxyphenyl) methane.

(D) Phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, naphthol, pyrocatechol, pyrogallol monomethyl ether, pyrogallol-1,3-dimethylether, gallic acid, partially esterified or partially etherified gallic acid Such compounds having a hydroxyl group.

The blending amount of the photosensitive component is represented by the alkali-soluble resin or a polyhydroxy compound optionally used with the alkali-soluble resin, for example, general formula (II), and general formulas (V) and (VI) described below. It is preferably selected in the range of 5 to 100% by weight, preferably 10 to 50% by weight, based on the total amount of the compound and the compound. If the amount is less than 5% by weight, an image faithful to the pattern cannot be obtained, and the transferability decreases. If the amount exceeds 100 parts by weight, the uniformity of the formed resist film decreases and the resolution deteriorates. I do.

The composition of the present invention may contain the following additional components, if necessary, as long as the object of the present invention is not impaired. For increasing the depth of focus or enhancing the sensitizing effect at a high numerical aperture, 4,4'-bis (dialkylamino) benzophenone such as 4,4'-bis (dialkylamino) benzophenone
4'-bis (dimethylamino) benzophenone, 4,
4'-bis (diethylamino) benzophenone, 4,
4'-bis (di-n-propylamino) benzophenone, 4,4'-bis (di-isopropylamino) benzophenone, 4,4'-bis (dibutylamino) benzophenone, 4-dimethylamino-4'-diethylaminobenzophenone , 4- (N-methyl-ethylamino)-
Examples include aminobenzophenones such as 4 '-(N-methyl-ethylamino) benzophenone, which may be used alone or in combination of two or more. Among these, 4,4'-bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone are particularly preferred.

Such aminobenzophenones are used in an amount of 0.1 to 1.0% by weight, preferably 0.1 to 0.5% by weight, more preferably 0.1 to 0.5% by weight, based on the total solids of the composition excluding the aminobenzophenones. It is selected in the range of 1 to 0.3% by weight. If the amount is less than 0.1% by weight, the effect of the addition is insufficient, and if it exceeds 1.0% by weight, the resolution and sensitivity tend to deteriorate.

Compounds which enhance the sensitizing effect include compounds represented by the general formula (II),

Embedded image (In the formula, R ¹¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ^{12 to} R ¹⁷ are a hydrogen atom, a halogen atom,
An alkyl group of 4 or an alkoxy group having 1 to 4 carbon atoms, p,
q and r are integers of 1 to 3), and

Embedded image (R ^{1 to} R ⁴ in the formula are a hydrogen atom, a halogen atom, a hydroxyl group,
An alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, R ⁷ is a hydrogen atom, a halogen atom or a carbon atom having 1 to 4 carbon atoms;
R ¹⁰ , R ¹¹ , R ¹⁸ , R ¹⁹ are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, 1 is an integer of 0 or 1 to 3,
and p is an integer of 1 to 3). These may be used alone or in combination of two or more. The compounding amount of these compounds is preferably selected in the range of 5 to 50% by weight, more preferably 10 to 35% by weight, based on the alkali-soluble resin.

In order to improve the resolution and the remaining film ratio, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3 , 5-Tris (4-tert-butyl-3-hydroxy-2,6-diethylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-te
Isocyanurate compounds such as (rt-butyl-4-hydroxybenzyl) isocyanurate are used. These may be used alone or in combination of two or more. The mixing ratio is preferably 0.5 to 1 with respect to 100 parts by weight of the alkali-soluble novolak resin.
5 parts by weight, more preferably in the range of 1.0 to 10 parts by weight.

The composition of the present invention may further contain, if necessary, a compatible additive such as an additional resin, a plasticizer, a stabilizer or a developed image for improving the performance of the resist film. A commonly used material such as a coloring agent for visualization can be added and contained.

The composition of the present invention is preferably used in the form of a solution obtained by dissolving the alkali-soluble resin, the photosensitive component and various optional components used as desired in a suitable solvent. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone; ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, and monomethyl ethers thereof. , Polyethyl alcohols such as monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate , Ethyl pyruvate, methyl methoxypropionate,
Esters such as ethyl ethoxypropionate can be mentioned. These may be used alone or as a mixture of two or more.

About the preferred method of using the composition of the present invention,
For example, first, on a support such as a silicon wafer, necessary components and additional components used as needed are dissolved in the above-described appropriate solvent to form a solution, which is coated with a spinner or the like, and dried. A light source that forms a photosensitive layer and then emits ultraviolet light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp,
Using ultra-high pressure mercury lamps, arc lamps, xenon lamps, etc.
Exposure is performed through a required mask pattern, or irradiation is performed while scanning an electron beam. Next, when this is immersed in a developing solution, for example, a weakly alkaline aqueous solution such as a 1 to 10% by weight aqueous solution of tetramethylammonium hydroxide,
The exposed portion is dissolved and removed, and an image faithful to the mask pattern can be obtained.

[0047]

As described above, the positive photoresist composition of the present invention comprises:
It can form a resist pattern with high resolution, excellent cross-sectional shape and heat resistance, and has high sensitivity, excellent focus depth width characteristics and halation prevention effect, and has a sufficient exposure margin, It is suitable for use as a substrate having a high reflectance or a substrate having high reflectivity, and is particularly suitably used as a resist for ultrafine processing useful for forming an ultrafine pattern of 64M-DRAM and thereafter.

[0048]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

The physical properties of the photoresist composition were determined as follows. (1) Sensitivity: The sample was applied on a silicon wafer using a spinner and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 1.05 μm. A reduction projection exposure apparatus NSR-1755i7B (manufactured by Nikon Corporation, NA =
0.54), and then exposed on a hot plate at 110 ° C. for 90 seconds, and then exposed to a 2.38% by weight aqueous solution of tetramethylammonium hydroxide at 23 ° C. When the film was developed for 1 minute, washed with water for 30 seconds and dried, the minimum exposure time at which the film thickness of the exposed portion after development became 0 was measured in milliseconds (ms) as the sensitivity.

(2) Resolution: The resolution was shown as the limit resolution at the exposure dose for reproducing a 0.40 μm mask pattern.

(3) Heat resistance: A resist pattern having a pattern line width of 5 μm formed on a silicon wafer was formed at 125 ° C., 130 ° C., 135
When baked on a hot plate at a temperature of 140 ° C. or 140 ° C. for 5 minutes, the temperature at which the resist pattern was deformed was shown.

(4) Pattern shape: The cross-sectional shape of the resist pattern having a width of 0.40 μm was determined by SEM.
(Scanning electron microscope) Observed by a photograph, a rectangular shape was designated as A, a slightly trapezoidal shape was designated as B, and a resist pattern having a rounded and tapered top was designated as C. .

(5) Depth of focus width: Using a reduction projection exposure apparatus NSR-1755i7B (manufactured by Nikon Corporation, NA = 0.54), Eop (0.40 μm
SEM photograph of a resist pattern obtained by performing exposure and development by appropriately shifting the focus at the exposure amount up and down, assuming that the exposure amount required to form a line-and-space is one-to-one. Was observed. The SE
The maximum value (μm) of defocus at which a 0.40 μm rectangular resist pattern was obtained from the M photograph was defined as the depth of focus.

(6) Exposure margin: Eop (line and space of 0.40 μm is one-to-one)
(Eop), which is the minimum exposure required to be formed on the substrate, is divided by Eth (the exposure at which the film thickness of the exposed portion after development becomes 0) (Eop).
/ Eth) was taken as the exposure margin. The higher this value, the more
The width of exposure latitude is wide and is preferable.

Production Example 1 1.0 mol of bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane and 2.0 mol of naphthoquinone-1,2-diazido-5-sulfonyl chloride Was added to 2700 g of dioxane, and the mixture was stirred and dissolved at room temperature for 60 minutes. A catalyst solution obtained by dissolving 4 mol of triethylamine in 1214 g of dioxane was added dropwise while controlling the addition rate so that the temperature rise due to the heat of reaction did not exceed 20 ° C. Then 1 at room temperature
After stirring for an hour, a mixed solution of hydrochloric acid and dioxane (weight ratio of 1:
1) was added dropwise until the reaction solution became acidic.
After stirring for 0 minutes, the generated precipitate was separated by filtration, and the filtrate was added to a large amount of pure water to precipitate crystals. The precipitated crystals were dehydrated by a centrifugal dehydrator and dried, then dissolved in dioxane, added to pure water and recrystallized for purification. This purification operation was repeated several times, and hydrochloric acid incorporated in the crystals,
Unreacted substances and the like were completely removed. afterwards. It was dried sufficiently in a vacuum freeze dryer.

The thus obtained crystals were analyzed by liquid chromatography (LPC), UV spectrum analysis,
As a result of IR analysis and gel permeation chromatography (GPC) analysis, it was found that the esterified product (a) had an esterification ratio of 56% and a diester content of 77% on a molar basis.

Production Example 2 Bis (5-cyclohexyl-4-hydroxy-2-hydroxy-2) instead of bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane
(Methylphenyl) -2-hydroxyphenylmethane except that an esterification ratio of 70 was obtained in the same manner as in Example 1.
%, And an esterified product (b) having a diester content of 73% on a molar basis was obtained.

Production Example 3 Bis (4-hydroxyphenyl) -3-methoxy-4-
1 mole of hydroxyphenylmethane and naphthoquinone-1,
3.0 mol of 2-diazide-5-sulfonyl chloride was added to 4000 g of dioxane, and the mixture was stirred and dissolved at room temperature for 60 minutes. 6 mol of triethylamine is added to dioxane 18
The catalyst solution dissolved in 00 g was dropped while adjusting the dropping rate so that the temperature rise due to the heat of reaction did not exceed 20 ° C. Next, the same operation as in Example 1 was performed to obtain an esterified product (c) having an esterification ratio of 98%, a diester content of 4% on a molar basis, and a triester content of 94% on a molar basis.

Comparative Production Example 1 Bis (4-hydroxyphenyl) -3-methoxy-4-
Bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3 instead of hydroxyphenylmethane
An esterified product (d) having an esterification rate of 81%, a diester content of 15% on a molar basis, and a triester content of 46% on a molar basis in the same manner as in Production Example 3 except that 4-dihydroxyphenylmethane was used. ) Got.

Comparative Production Example 2 Bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxy was used instead of bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane An esterified product (e) having an esterification ratio of 66% and a diester content of 55% on a molar basis was obtained in the same manner as in Production Example 1 except that phenylmethane was used.

Reference Example 1 m-cresol and p-cresol were added in a weight ratio of 40:60.
Of cresol novolak resin obtained by condensation in a conventional manner using an oxalic acid catalyst, and the low molecular weight region was cut to obtain a weight average molecular weight of 3,000 to 4,000. Cresol novolak resin was prepared. Resin 1 thus obtained
00 parts by weight, 35 parts by weight of the photosensitive component (a) obtained in Production Example 1, and bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane 25 as a sensitizer
After dissolving parts by weight in ethyl lactate, this was filtered using a membrane filter having a pore size of 0.2 μm to prepare a photoresist composition. Table 1 shows the sensitivity, resolution, heat resistance, exposure allowance, depth of focus, and physical properties of the pattern shape of this film.

Reference Examples 2 and 3, Examples 1 to 3 and Comparative Examples 1 to
2 A positive photoresist composition was obtained in the same manner as in Example 1 except that the photosensitive components were changed as shown in Table 1. Table 1 shows the sensitivity, resolution, heat resistance, exposure allowance, depth of focus, and physical properties of the pattern shape of this film.

[0063]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuo Tokutake 150 Nakamurako Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Tokyo Oka Kogyo Co., Ltd. (72) Inventor Hidekatsu Ohara 150 Nakamaruko Nakahara-ku Kawasaki-shi Kanagawa Prefecture Tokyo Oka Kogyo Co., Ltd. (72) Inventor Toshimasa Nakayama 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Within Tokyo Ohka Kogyo Co., Ltd. (56) References JP-A-6-301203 (JP, A) (58) Fields surveyed (Int .Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (9)

(57) [Claims] 1. A positive photoresist composition containing an alkali-soluble resin and a photosensitive component, wherein the photosensitive component has a general formula: (Where k, l and m are an integer of 0 or 1 to 3, and n is 1 or 2) quinonediazide sulfonic acid ester of at least one aromatic polyhydroxy compound selected from the compounds represented by the following formulas: Having an esterification rate of 50
% And a diester content of 60% or more on a molar basis, and a compound represented by the general formula: (Wherein R ^{1 to} R ⁶ are a hydrogen atom, a halogen atom, a hydroxyl group,
An alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, R ⁷ and R ^{8 each} represent a hydrogen atom, a halogen atom or
To 4 alkyl groups, R ⁹ is a hydrogen atom or a methyl group,
R ¹⁰ and R ¹¹ are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms) and a compound represented by the general formula: (In the formula, R ¹¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ^{12 to} R ¹⁷ are a hydrogen atom, a halogen atom,
At least one selected from a compound represented by the formula:
Quinonediazidosulfonic acid esters of an aromatic polyhydroxy compound, wherein the esterification rate is 50% or more;
A positive photoresist composition, which is a mixture with a triester content of 85% or more on a molar basis. 2. A compound of the general formula (Where k, l and m are 0 or an integer of 1 to 3, and n is 1 or 2) is a compound represented by the general formula: 2. The positive photoresist composition according to claim 1, wherein k, l and m in the formula are compounds represented by 0 or an integer of 1 to 3. 3. A compound of the general formula (Where k, l and m are 0 or an integer of 1 to 3, and n is 1 or 2). 2. The positive photoresist composition according to claim 1, wherein k, l and m in the formula are compounds represented by 0 or an integer of 1 to 3. 4. A compound of the general formula (Where k, l and m are each an integer of 0 or 1 to 3, and n is 1 or 2). (Where k, l and m are 0 or an integer of 1 to 3) and a compound represented by the general formula: The positive photoresist composition according to claim 1, wherein the composition is a mixture with a compound represented by the formula (where k, l and m are 0 or an integer of 1 to 3). 5. A compound of the general formula The compound represented by the formula (where k, l and m are 0 or an integer of 1 to 3) is bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -3,4-dihydroxyphenylmethane. 5. The positive photoresist composition according to 2 or 4. 6. A compound of the general formula The compound represented by the formula (where k, l and m are 0 or an integer of 1 to 3) is bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane. 5. The positive photoresist composition according to item 4. 7. The positive photoresist composition according to claim 1, wherein the quinonediazidesulfonic acid is naphthoquinone-1,2-diazidosulfonic acid. 8. The positive photoresist composition according to claim 1, wherein the alkali-soluble resin is an alkali-soluble novolak resin. 9. A compound of the general formula (In the formula, R ¹¹ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ^{12 to} R ¹⁷ are a hydrogen atom, a halogen atom,
9. The compound represented by formula (1), which is an alkyl group having 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms) is bis (4-hydroxyphenyl) -3-methoxy-4-hydroxyphenylmethane. A positive photoresist composition.