JPH04153656A - Positive type photoresist composition and pattern forming method using same - Google Patents

Abstract

PURPOSE:To enhance resolution in the case of exposure to the i-line of 365nm wavelength by incorporating an alkali-soluble resin and an ester of 1,2- naphthoquinone-(2)-diazido-6-sulfonic acid with one of alcohols and phenols as essential components. CONSTITUTION:The photoresist composition comprises the alkali-soluble resin and the ester of 1,2-naphthoquinone-(2)-diazido-6-sulfonic acid with one of alcohols and phenols or the amido of the 1,2-naphthoquinone-(2)-diazido-6-sulfonic acid with one of organic amines as essential components, thus permitting the composition to be high in transparency to the i-line, very much in solubility difference between exposed parts and unexposed parts, to have absorption wavelength on the longer wavelength side as compared with the conventional positive type photoresists and therefore, to obtain high sensitivity to argon laser beams to be obtained.

Description

Detailed Description of the Invention <Industrial Utilization Public Funds> The present invention provides a novel positive-working photoresist composition sensitive to radiation, particularly a positive-working photoresist composition suitable for radiation irradiation of a specific wavelength, and the positive-working photoresist composition. The present invention relates to a pattern forming method using a photoresist composition.

<Prior Art> As a positive photoresist, an alkali-soluble resin and a naphthoquinonediazide compound are generally used as a dissolution inhibitor. The alkali-soluble resin mentioned above is generally a novolac resin, and a positive photoresist using the novolac resin can be made with an aqueous alkaline solution! Since it can be developed without getting wet, it has extremely high resolution, and when the generated image is used as an etching mask,
It is particularly useful because it has high resistance to plasma etching.

Recent advances in semiconductor technology have led to higher integration and miniaturization, and photoresists are now required to have a resolution of half a micron or less.

By the way, reduction projection exposure is currently mainly used for resist exposure in the formation of fine patterns in semiconductor integrated circuits and magnetic valves. The resolution R in the reduction projection exposure method is expressed by Rayleigh's equation (1), and methods for improving this resolution are as follows:
There are three methods: (1) increasing the numerical aperture of the lens expressed by NA, (1) shortening the wavelength (λ) of the exposure light, and (2) decreasing the value of a constant determined by the resist process.

In the past, improvement in resolution was mainly due to increasing the NA of the stepper and improving the resist process. However, increasing the NA of the lens causes a problem in that the depth of focus (DOF) λ DOF=±2(NA)·=(2) expressed by the following equation (2) becomes shallower.

On the other hand, shortening the wavelength^ has a high effect on the depth of focus.
In recent years, reduction projection exposure equipment that uses a shorter wavelength mercury lamp III (wavelength 365 nm) as a light source, instead of the g-line (wavelength 436 nm) of a conventional mercury lamp, and its use have been developed. A resist has been developed. Currently, the g-blocking agent for commercially available III resists is the same as for g-ray resists, 1,2-naphthoquinonediazide-4-sulfonic acid, or 1,2-naphthoquinonediazide-5-sulfonic acid and phenols. esters are mainly used.

<Problems to be Solved by the Invention> However, the above-mentioned 111 resist has problems in that the resolution for one-line exposure is insufficient and the shape of the obtained resist pattern is not very good.

This is the above-mentioned dissolution inhibitor. When esters of 1,2-naphthoquinonediazide-4-sulfonic acid or 5-sulfonic acid and phenols are used for one line, g
This is because the transmittance is lower than when used for lines, and as the light reaches the lower part of the resist, the difference in exposure between the upper and lower parts of the resist becomes large.

For this reason, the content of the dissolution inhibitor is lowered to reduce the resist's tiling.
If the transmittance to 1 is increased, the difference in dissolution rate in the developing solution between exposed and unexposed areas of the resist becomes smaller, resulting in a problem of film thinning.

Another problem with conventional Bonn type photoresists is that they cannot be used against long wavelength light emitted by argon ion lasers, etc.
The sensitivity is low. For example, when creating an optical disc master, a positive photoresist coated on a glass disk is exposed to light using an argon ion laser to create pits.
Since there is almost no absorption at the wavelength of 488 nm oscillated by the laser, there is a problem that exposure takes a long time.

In view of the above-mentioned circumstances, the present invention provides a positive photoresist composition that has a high transmittance for one line and a large difference in solubility in a developing solution between exposed and unexposed areas, and pattern formation using the composition. The purpose is to provide a method.

Another object of the present invention is to provide a positive photoresist composition that is highly sensitive to light oscillated by an argon ion laser and a pattern forming method using the composition.

Means for Solving the Problems> In order to achieve the above object, the present inventors have conducted intensive research and found that by using an alkali-soluble resin and a quinonediazide compound having a specific structure, the present inventors have achieved a method that is transparent to IIB. The dissolution rate difference between exposed and unexposed areas in the developing solution is very large, and the absorption wavelength is on the longer wavelength side than conventional positive photoresists, so it has high sensitivity to argon ion laser exposure. It has been found that a positive-working photoresist composition can be obtained having the following properties.

The composition of the positive photoresist composition of the present invention based on this knowledge is: (,) an alkali-soluble resin, (bll, an ester of 2-naphthoquinone-(2)-diazide 6-sulfonic acid and an alcohol or a phenol), It is also characterized by containing 1!1.2-naphthoquinone-(2)-diazide-6-sulfonic acid and a sulfonamide of organic amines as essential components.

On the other hand, a pattern forming method using a positive photoresist composition is as follows: (a) an alkali-soluble resin and (bl 1,
Esters of 2-naphthoquinone-(2)-diazido-6-sulfonic acid and alcohols or phenols, or sulfoleamides of 1,2-naphthoquinone-(2)-diazido-6-sulfonic acid and organic amines. (1) forming a positive photoresist layer on a substrate using a positive photoresist composition containing as an essential component; (2) exposing the positive photoresist layer to light according to a predetermined pattern; Develop the layer with an alkaline developer.

It is characterized by

The present invention has surprisingly found that the above-mentioned problems can be solved by using the above-mentioned quinonediazide ester or amide as a dissolution inhibitor. This is because the positive photoresist composition of the present invention has 1) higher transmittance in l and wI, 2) absorption on the long wavelength side, and 2) lower dissolution inhibition ability than conventional positive photoresist compositions. This is because it has the property of being extremely large.

The present invention will be explained in detail below.

In the present invention, examples of the alkali-soluble resin include novolak resin, poly(hydroxylestyrene) or its derivatives, and copolymers having repeating units having a structure represented by the following general formula (2).

(In the formula, R1 represents hydrogen, an alkyl group, or an aryl group, R2 represents hydrogen, a halogen, an alkyl group, or an alkoxy group, and n represents an integer of 0 to 6.) The novolac resin contains phenols and ketones. It can be obtained by condensation of the above in the presence of an acid catalyst.

Examples of phenols used in this case include phenol, 0-cresol, m-cresol, p-cresol, 0-ethylphenol, m-ethylphenol,
p-ethylphenol, 0-butylphenol, m-butylphenol, p-butylphenol, 2.3-xylenol, 2,4-xylenol, 2.5-xylenol, 3,4-xylenol, 3.5-xylenol, p
-7enylphenol, hydroquinone, catechol, resorcinol, pyrogallol, α-naphthol, β-naphthol, bisphenol A, and the like. These phenols may be used alone or in combination of two or more.

Examples of ketones include formaldehyde, paraformaldehyde, acetaldehyde, tetrapionaldehyde, benzaldehyde, acetone, and methyl ethyl ketone. These ketones can be used alone or in combination with L.

Poly(hydroxystyrene) and its derivatives are obtained by copolymerizing hydroxystyrenes, Ml, 211Jl, with the above or other acrylic monomers. Examples of the hydroxystyrenes include 0-hydroxystyrene, m-hydroxystyrene, p-bitroxystyrene, 3-methyl-4-hydroxystyrene, 3,
5-dimethyl-4- and droxystyrene, α-methyl-
Can you name 〇-hydroquinestyrene, a-methyl-m-hydroxystyrene, and a-methyl-p-hydroxystyrene? Examples of the acrylic monomer as a copolymerization component include acrylic ester, methacrylic ester, acrylic amide, methacrylic amide, and acrylonitrile.

In addition, copolymers having repeating units of maleimide conductors represented by the general formula are examples or JP-A No. 61-16
It is disclosed in JP-A No. 2039, JP-A-62-151408, JP-A-62151-409, and the like.

The quinone diazi F compound which is the dissolution inhibitor in the present invention is represented by the following formula (I): 1,2-naphthoquinone-(
It can be obtained by reacting 21-diazide-6-sulfonyl halide with an alcohol, phenol, or a primary or secondary organic amine in the presence of a dehydrohalogenating agent.

(In the formula, X represents chlorine or bromine.) Alcohols, phenols, or primary or secondary organic amines used in the above reaction include: ``Li'' by J. Kosai.
ght-Sensitive SystemsJohn
Wily & 5ons, Inc., N
ew York, 1965. Examples include compounds described in pp. 339 to 357. In addition, for example,
USP-3,048,120, USP-3,048,
No. 121, USP-3,061,430, USP-3
, No. 102,809, USP3, No. 106.465, U.
SP-3,180,733, USP-3,184,3
No. 10, USP-3,201,239, U.S.P.
-163a No. 705, JP-A-58-X50948,
JP-A-58-17112, JP-A-58-182632
No., JP-A-59-165053, JP-A-80-134
No. 235, JP-A-60-146234, JP-A-80-
154249, JP 60-163043, JP 61-97278, JP 61-209439, JP 62-10645, JP 62-10646,
JP 62-36663, JP 63-24244, JP 63-110446, JP 63-1194
No. 50, JP-A-63-178229, JP-A-63-1
No. 80947, JP-A-63-208840, JP-A-6
3-279248, JP 63-305348, JP 64-17049, JP 1-147538,
JP-A-1-177031, JP-A-1-189644, JP-A-1-291240, JP-A-1-291241
No., JP-A No. 1-291242, JP-A No. 1-29124
No. 3, JP-A No. 2-309052, JP-A No. 2-3235
No. 1, JP-A No. 2-32352, JP-A No. 2-40352
Alcohols, phenols [and Examples include amines.

Among the above-mentioned alcohols, phenols, and organic amines, polyhydric phenols can be cited as phenols that have particularly good stability over time and a large ability to prevent dissolution in alkali-soluble resins.

A conventional method is used for the reaction of 1.2-7toquinone-(2)-diazide-6-sulfonyl halide with alcohols, phenols, or primary or secondary organic amines. That is, alcohols, phenol l [also +! 1
m or secondary organic amines, 1,2-naphthoquinone (21-diazido-6-sulfonyl halide, and acetone, methyl ethyl ketone dioxane, tetrahydrofuran, acetonitrile.

Solvents such as pyridine, methyl cellosolve acetate, γ-butyrolactone, γ-valerolactone, dimethylimidazolidinone, N-methylpyrrolidone, acetonylacetone, and sulfolane are charged into a reaction vessel, and a basic catalyst, which is a dehydrohalogenating agent, is charged. , for example, sodium hydroxide, potassium hydroxide, sodium carbonate.

Non-metallic salts such as potassium carbonate and sodium hydrogen carbonate, diethylamine, jetanolamine, triethylamine, triethanolamine, N-n-butylgetanolamine, tri-n-butylamine, pyridine.

Condensation is carried out by dropping an organic basic catalyst such as picoline.

In addition, when reacting using polyalcohols, polyhydroxyphenols, and polyamines, a mixture of compounds with widely different esterification or amidation numbers and esterification or amidation positions is obtained, and usually a mixture of compounds is obtained. Please be used as is.

The positive photoresist composition of the present invention is prepared by dissolving the above-mentioned specific quinonediazide compound and an alkali-soluble resin in a suitable solvent, and filtering the solution through a filter with a pore size of about 0.2 μm, for example.

Examples of the solvent used here include ethers such as dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, and propylene glycol diethyl ether; ethylene glycol monomethyl ether;
Glycol monoethers such as ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; Ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone; ethyl acetate, butyl acetate, methyl cellosolve acetate, Ethyl cellosolve acetate, methoxypropyl acetate,
Esters such as ethoxypropyl acetate, dimethyl oxalate, methyl lactate, and ethyl lactate; Amides such as N, N-dimethylformamide, N, N-remethylacetamide; Pyrrolidones such as N-zotylpyrrolidone;
Examples include lactones such as γ-butyrolactone; and sulfoxides such as dimethyl sulfoxide. Note that these solvents may be used alone or in combination of 2a1 or more. The concentration of the above components (total solid content including additives) is suitably 2 to 50% by weight.

There is no particular restriction on the blending ratio of the alkali-soluble resin and the quinone rarecite compound in the positive-working photoresist composition of the present invention.
parts by weight, preferably 5 to 50 parts by weight.

If this amount is less than 2 parts by weight, the resolution of the resist pattern is poor, and the current (
This is probably because the filtration film decreases and becomes larger in the unexposed area after tiring.On the other hand, if this amount exceeds 80 parts by weight, it is impossible to obtain a composition with high sensitivity. Composition: A quinodidiazide compound other than the specific quinonediand compound, such as a 1,2-naphthoquifury(2]-diazide-4-sulfonic acid ester or ester) is a 1,2-naphthokifle-(2+-i) and-5-sulfonic acid ester can be blended, for example, at a ratio of 50 parts by weight, preferably 20 parts by weight, per 100 parts by weight of the alkali-soluble resin. If necessary, in order to improve developability, film strength, or storage stability of the composition, 50 parts by weight, preferably 20 parts by weight of a known polymer compound is added to 100 parts by weight of the alkali-soluble resin. It can also be additionally contained in a proportion of parts by weight or less. Examples of such polymer compounds include natural polymer compounds such as rosin and silk, polyvinyl formal resin, polyvinyl butyral resin, polyvinyl acetal resin, polyester resin, and epoxy resin. , alkyd resins, polyurethane ia! resins, polyamide resins, copolymers of styrene and maleic anhydride, acrylic ester polymers, styrene and acrylic acid, methacrylic acid, ζ, these alkyl ester copolymers, and polyvinylpyrrolidone. Synthetic polymer compounds such as

If necessary, the positive photoresist composition of the present invention may further include a printout agent for forming a visible image, an antihalation agent such as a dye or pigment to reduce the effect of halation, and a substrate. It is possible to contain an adhesion aid such as a silane coupling agent to improve adhesion to the resist layer, a surfactant to improve coating properties, and the like.

It is effective to use the positive photoresist composition of the present invention by coating it on a substrate, drying it to form a positive photoresist layer, exposing it to light according to a predetermined pattern, and then developing it with an alkaline developer to form a pattern. be.

Next, an example of the pattern forming method of the present invention will be described.

First, the resin composition of the present invention is applied onto a substrate and dried to form a radiation-sensitive resin layer.

Depending on the purpose, the substrate may be silicon, silicon dioxide, silicon nitride, polysilicon, ceramics, aluminum, copper, aluminum oxide, glass, TO,
Use plastic film, paper, etc.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, and curtain coating can be used.

After applying the resin composition to the substrate, the coated substrate is heat-treated at about 20°C to 150°C.

This heat treatment is performed to reduce the concentration of the solvent in the resin composition, and the preferred range of heat treatment is 5.
The temperature is 0 to 150°C for 10 seconds to 30 minutes. This heat treatment is preferably carried out until the rate of change in solvent removal becomes relatively small, and the temperature and time are determined depending on the properties of the resin composition.
Set as appropriate depending on the order of solvent application, amount of application, etc.

Next, exposure is performed according to a predetermined pattern, and visible light, ultraviolet light, XS, electron beam, etc. can be used as the light to be irradiated. Examples of these light sources include fluorescent lamps, carbon arc lamps, mercury lamps, chemical lamps, xenon lamps, metal halide lamps, and argon ion lasers.
Visible and ultraviolet sources such as F-excimer laser, XeC1 excimer laser, ArF-excimer laser,
X-ray sources such as electron beam excitation, plasma radiation and synchrotron radiation, and electron beam sources such as thermionic radiation and field radiation can be mentioned, but in particular, it is preferable to use a single ray from a mercury lamp or light from an argon ion laser. suitable.

A pattern is then formed by developing the positive photoresist layer with an alkaline 3 developer. Examples of alkaline developers used here include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate,
Inorganic alkalis such as sodium silicate, sodium metasilicate, and aqueous ammonia; Primary amines such as ethylamine and n-propylamine; Diethyla 2'J1-
Secondary amines such as propylamine; Tertiary amines such as triethylamine and methyldiethylamine; Alcohols such as dimethylethanolamine and triethanolamine; Tetramethylammonium hydroxide, tetraethylammonium hydroxide, and hydroxyethyltrimethylammonium hydroxy 4th such as do
alkylamines such as cyclic amines such as pyrrole, piperidine, and morpholine; alcohol amines such as jetanolamine and triethanolamine; tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethyl(2- Examples include aqueous solutions of quaternary ammonium salts such as hydroxyethyl) ammonium hydroxide, and cyclic amines such as pyrrole and piperidine.

Further, other additives such as surfactants, wetting agents, stabilizers, and small amounts of organic solvents can be added to the developer as necessary.

After exposure, bake at approximately 80 to 150°C (P
EB: post-exposure-bake) may be performed. The PEB causes diffusion of the photosensitizer, reduces the influence of standing waves, and provides a good pattern.

Example of implementation Next, the present invention will be explained in more detail with reference to Examples.

(Synthesis example) Synthesis example 1 Synthesis of naphthoquinonediazide compound A 4.67 g (0,016 mol) of 4,4',4'-trihydroxytriphenylmethane and 1,2-naphthoquinone-(2)-diazide-6 -sulfonyl chloride
10.75 g (0,040 mol) and dioxane 20
0 g was placed in a 300 mj' 3-tube flask and stirred to dissolve.

4.45 g of triethylamine was then added to this mixture.
(0,040 mol) was added dropwise at 20 to 25°C over 30 minutes. After completion of the dropwise addition, the mixture was reacted at 30° C. for 4 hours.

The reaction mixture was poured into 11 ml of ion-exchanged water, and the resulting precipitate was dried separately to yield 4.4'.

1゜2-naphthoquinone-(21-diazide-6-sulfonic acid ester (naphthoquinonediazide compound A) 13.29 g of 4'-trihydroxytriphenylmethane!e
4.

Synthesis Example 2 Synthesis of Naphthoquinone Diazide Compound B 2.2-bis(2,4-dihydroxyphenyl)propane 3.47 g (0,0133 mol) 1,2 Naphthoquinone-<21-diazide-6-sulfonyl chloride Z0
．． 75g (0,040 mol) and 200g dioxane
was charged into a 300 mj 3-tube flask and dissolved with stirring.

Then 4.45 g of trimethylamine (0,
044 mol) was added dropwise at 20 to 25°C over 30 minutes.

After completion of the dropwise addition, the mixture was reacted at 30° C. for 4 hours.

The reaction mixture was poured into 1 liter of ion-exchanged water, and the resulting precipitate was dried separately.
2) 12.87 g of -diazide-6=sulfonic acid ester (naphthoquinonediazide compound B) was obtained.

Synthesis Examples 3 and 4 Naphthoquinonediazide Compounds C and D (Comparative Example) In Synthesis Examples 1 and 2, 1,2-naphthoquinone-(2
)-diazide-6-sulfonyl chloride, 1,
Synthesized in exactly the same manner except for using 2-naphthoquinone-(2)-diazide-5-sulfonyl chloride,
4.4', 1,2-nafdoquinone-(2)-diazide-5-sulfonic acid ester of 4' trihydroxytriphenylmethane (naphthoquinonediazide compound C) and 2
, 1,2-naphthoquinone-[2)-diazide-5-sulfonic acid ester of 2-bis(2,4-dihydroxyphenyl)furopane (naphthoquinonediazide compound D) was obtained.

Synthesis Example 5 Synthesis of novolac resin 60 g of m-cresol 40 g of p-cresol 55 g of a 37% by weight formalin aqueous solution and 0.05 g of oxalic acid
The mixture was placed in a 0 mj 3 flask and reacted for 5 hours in an oil bath at 100° C. while stirring. After the reaction, the pressure was reduced after cooling.

Then, the temperature was gradually raised to 150°C to remove water and monomers.

The weight average molecular weight of the obtained novolac resin in terms of polystyrene was 8,200.

(Example) Examples 1 to 2 and Comparative Examples 1 to 4 The photosensitizer and alkali-soluble resin shown in Table 1 below were dissolved in ethyl cellosolve acetate so that the solid content was 30% by weight. A photoresist composition was prepared by filtration using a membrane filter.

These photoresist compositions were coated on a quartz plate, and
After drying at °C for 30 minutes, one line was exposed and the A and B parameters used in the Dllll model were measured.

Further, the above photoresist composition was coated on a silicon wafer to a film thickness of about 1.2 μm, and the photoresist composition was coated at 80° C. for 30 minutes.
Dry for a minute. M light t&, 2.38% tetramethylammonium hydroxide aqueous solution w! ! After developing the photoresist by dipping it in NMD-3 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 25° C. for 60 seconds, the residual film rate, relative sensitivity, and γ value of the photoresist were determined.

These results are shown in Table 2.

*In the modeling of the exposure process proposed by ID1ll, each parameter is expressed by the following formula (TEEE
Trans, , Electron Devlees
, ED-22,7, p445-452, Suka).

Here, Tr: resist film thickness T(0):! ! Transmittance T of previous resist (oo)
: Transmittance of resist after exposure book 2 Nikkei Microdevice (published by Nihon Keizai Shimbun) November 1989 issue 178
From Table 1 of the numerical values listed on pages 178 and 178, the relative values of the exposure seconds that allow the M element to pass through, the photoresist layer according to this example has an A value that represents the ratio of transmittance before and after exposure; It can be seen that both the B value, which indicates the transparency after exposure, is small, and the transparency is high both before and after exposure.

Further, from Table 2, the photosensitizer in the photoresist according to this example has a much higher insolubilization ability than the photosensitizer of the reference example.

Therefore, it can be seen that the photoresist of the present invention has a high residual film rate and a high γ value even if it contains only a small amount of photosensitizer component.

Example 3 and Comparative Example 5 The photoresist composition of Example 1-■ was applied to a silicon wafer using a spinner so that the film thickness was 2 μm.
Dry in oven at 80°C for 30 minutes.

As a comparative example, positive photoresist 0F manufactured by Tokyo Ohka Kogyo Department
A resist film was formed on a silicon wafer in exactly the same manner using PR-800 (trade name).

These were irradiated with 488 nm light using an argon ion laser, and then deep developed in a 2.38% tetramethylammonium hydroxide aqueous solution (NMD-3. trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 25°C for 60 seconds. The rate and relative sensitivity were measured.

These results are shown in Table 3.

From Table 3, it can be seen that the photoresist composition of this example has high sensitivity to argon ion laser and a high residual film rate.

Example 4 The positive photoresist composition of Example 1 (1) was applied onto a silicon wafer to a thickness of 1.1 μm using a spinner, and then dried on a hot plate at 110° C. for 90 seconds. Next, i11Bm small projection exposure system [; NSR15
05i 6A'7 Eher stepper, Konsha m, NA=0
．． 45)! Using 38% tetramethylammonium hydroxide in water after exposure through a test chart mask? ! ! (manufactured by Tokyo Ohka Kogyo Co., Ltd., NMD3; product name)
The film was developed for 60 seconds at 25°C.

When the obtained pattern was observed with an electron II microscope, it was found that 0.
It was confirmed that a 4 μm l/s pattern was formed in a rectangular shape without film loss.

<Effects of the Invention> As described above in detail with Examples, the present invention provides a positive photoresist composition that has high transparency to +i@ and a large difference in solubility in a developer between exposed and unexposed areas. It is possible to provide a pattern forming method capable of forming a good pattern using a material and a composition thereof.

Therefore, the positive-working photoresist composition and pattern forming method according to the present invention are suitable for use in forming fine patterns in, for example, semiconductor integrated circuits and magnetic valves.

Furthermore, the present invention can provide a positive photoresist composition that is highly sensitive to light oscillated by an argon laser and has a high residual film, and a pattern forming method using the same, which is particularly suitable for, for example, the production of disk masters. Become.

Claims (1)

[Claims] 1) (a) an alkali-soluble resin; (b) 1,2-naphthoquinone-(2)-diazide-6-
It is characterized by containing as an essential component an ester of sulfonic acid and alcohol or phenol, or a sulfonamide of 1,2-naphthoquinone-(2)-diazide-6-sulfonic acid and organic amines. Positive photoresist composition. 2) (1) forming a positive photoresist layer on a substrate using the positive photoresist composition according to claim 1; (2) exposing the positive photoresist layer to light according to a predetermined pattern; (3) then . A pattern forming method using a positive photoresist composition, characterized in that the positive photoresist layer is developed with an alkaline developer. 3) A pattern forming method using a positive photoresist composition according to claim 2, wherein the positive photoresist layer is exposed to i-line from a mercury lamp. . 4) A pattern forming method using a positive photoresist composition according to claim 2, wherein the positive photoresist layer is exposed to an argon ion laser beam.