JPH05333540A - Positive resist composition - Google Patents

Abstract

PURPOSE:To obtain a composition having balanced sensitivity, residual film rate, resolution, dimensional controllability, etc., by incorporating an alkali- soluble phenol resin, a quinone diazide sulfonic ester photosensitive agent and a specified monohydroxy compd. CONSTITUTION:The composition contains an alkali-soluble resin, a quinone diazide sulfonic ester photosensitive agent and a monohydroxy compd. shown by the formula. In the formula, R1...R5 are selected from hydrogen atom, halogen atom, 1-8C alkyls and 2-5C alkenyls, X is a single bond, -C(=O)-, -CO-, -C(-R7)(-R8)or -CH2O-, and R7 and R8 are selected from hydrogen atom and 1-4C alkyls. The composition consists preferably of 1000 pts.wt. of the phenol resin, 1-1000 pts.wt. of the photosensitive resin, 1-100 pts.wt. of the compd. and a solvent sufficient to dissolve the components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist composition, and more particularly to a positive resist composition for microfabrication required for manufacturing semiconductor devices, magnetic bubble memory devices, integrated circuits and the like. ..

[0002]

2. Description of the Related Art A method of forming a fine pattern using a photoresist is generally a method in which a solution containing a photosensitive material is applied on a substrate and dried to form a photosensitive film, which is then activated through a mask pattern. It is irradiated with light rays to form a latent image, which is then developed to form a negative or positive image. In the case of a positive resist, the exposed area has a higher solubility in the developing solution than in the non-irradiated area to give a positive image, whereas in the negative resist, the solubility of the exposed area in the developing solution decreases, and the negative area is negative. Give a pattern.

When a semiconductor element is manufactured by fine processing using a resist, a silicon wafer is used as a substrate, a negative or positive image is formed by the above method, and then the resist remaining on the substrate is used as a protective film for etching. After that, the resist film is removed.

In recent years, as ICs, LSIs, and VLSIs have become highly integrated, highly densified, and miniaturized, a technique for forming finer patterns has been required.
Demand for positive resists is increasing due to their high resolution and non-swelling properties. Currently, a positive resist generally used in this field is a resist composition containing an alkali-soluble resin such as a novolac resin and a quinonediazide compound, and uses an alkaline aqueous solution as a developer. Recently, the resolution has been improved and the formation of fine patterns of 1 μm or less has become possible by improving the performance of positive resists and improving the performance of exposure machines.

By the way, in forming a fine pattern of 1 μm or less, it is necessary to more strictly control the size of the pattern formed by the resist. However, satisfactory results have not always been obtained with conventional positive resists, and there has been a strong demand for positive resist compositions having good dimensional controllability.

[0006]

The object of the present invention is to have an excellent balance of various characteristics such as sensitivity, residual film ratio, and resolution, and particularly in the fine processing for forming a fine pattern of 1 μm or less, the exposure amount. Dimensional change is small,
It is to provide a positive resist composition having an excellent so-called exposure margin (exposure latitude).

The present inventors have conducted extensive studies to overcome the above-mentioned problems of the prior art, and as a result, in a positive resist composition containing an alkali-soluble phenol resin and a quinonediazide sulfonic acid ester type photosensitizer, a more specific It was found that the above object can be achieved by containing a monohydroxy compound having a structure, and the present invention has been completed based on the findings.

[0008]

Thus, according to the present invention, (a) an alkali-soluble phenol resin, (b) a quinonediazidesulfonic acid ester photosensitizer, and (c) a monohydroxy compound represented by the following general formula [I]: Provided is a positive resist composition containing a compound.

[0009]

[Chemical 2] R _{1 to} R ₅ : each independently a hydrogen atom, a halogen atom,
It is selected from an alkyl group having 1 to 8 carbon atoms and an alkenyl group having 2 to 5 carbon atoms.

[0010] R ₇ and R ₈ are each independently a hydrogen atom and a carbon number of 1 to
4 alkyl groups. Each of these components is usually used by uniformly dissolving it in a solvent.

The present invention will be described in detail below. (Alkali-soluble phenol resin) Examples of the alkali-soluble phenol resin used in the present invention include condensation reaction products of phenols and aldehydes,
Examples thereof include condensation reaction products of phenols and ketones, vinylphenol polymers, isopropenylphenol polymers, hydrogenation reaction products of these phenol resins, and the like.

Specific examples of the phenols used here include monovalent phenols such as phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol, and phenylphenol; resorcinol, pyrocatechol, hydroquinone, bisphenol A, pyrogallol, etc. And the like. Specific examples of the aldehydes include formaldehyde, acetaldehyde, benzaldehyde, terephthalaldehyde and the like. Specific examples of the ketones include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone and the like. These condensation reactions can be carried out according to conventional methods such as bulk polymerization and solution polymerization.

The vinylphenol polymer is selected from a homopolymer of vinylphenol and a copolymer of vinylphenol and a copolymerizable component. Specific examples of the copolymerizable component include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, vinyl acetate, acrylonitrile, and derivatives thereof.

The isopropenylphenol polymer is selected from isopropenylphenol homopolymers and copolymers with isopropenylphenol-copolymerizable components. Specific examples of the copolymerizable component include acrylic acid, methacrylic acid, styrene, maleic anhydride, maleic imide, vinyl acetate, acrylonitrile, and derivatives thereof.

When a hydrogenation reaction product of a phenolic resin is used, the product can be produced by any known method. For example, it is achieved by dissolving a phenol resin in an organic solvent and introducing hydrogen in the presence of a homogeneous or heterogeneous hydrogenation catalyst. The hydrogenation rate is usually 0.1 to 70%, preferably 1 to 50%.
%, And more preferably 3 to 40%.

These alkali-soluble phenolic resins may be used as they are, but those having a controlled molecular weight and a controlled molecular weight distribution may be used. Examples of the method for fractionation for controlling the molecular weight and the molecular weight distribution include a method of pulverizing an alkali-soluble resin or dissolving it in a suitable good solvent, and performing solid-liquid or liquid-liquid extraction with an organic solvent having an appropriate solubility. Be done. These alkali-soluble phenolic resins may be used alone or in combination of two or more.

(Quinonediazidesulfonic acid ester photosensitizer) The photosensitizer used in the present invention is not particularly limited as long as it is a quinonediazidesulfonic acid ester. The quinonediazidesulfonic acid ester can be generally synthesized by an esterification reaction between a compound having an —OH group and a quinonediazidesulfonic acid compound.For example, quinonediazidesulfonic acid is converted into sulfonyl chloride with chlorosulfonic acid according to a conventional method, It can be obtained by subjecting the obtained quinone diazide sulfonyl chloride and a compound having an —OH group to a condensation reaction.

For example, a compound having a --OH group and 1,2-
Dissolve a predetermined amount of naphthoquinonediazide-5-sulfonyl chloride in a solvent such as dioxane, acetone, or tetrahydrofuran, and add a basic catalyst such as triethylamine, pyridine, sodium carbonate, sodium hydrogen carbonate, sodium hydroxide, or potassium hydroxide. The resulting product can be prepared by washing with water and drying.

The compound having an --OH group used here is not particularly limited, and for example, a known compound having a phenolic hydroxyl group can be preferably used. As a typical example,
2,3,4-trihydroxybenzophenone, 2,4
4'-trihydroxybenzophenone, 2,3,4
4'-tetrahydroxybenzophenone, 2,4
2 ', 4'-tetrahydroxybenzophenone, 2,
Polyhydroxybenzophenones such as 3,4,2 ′, 4′-pentahydroxybenzophenone; gallic acid esters such as methyl gallate, ethyl gallate, propyl gallate; 2,2-bis (4-hydroxyphenyl) propane , Polyhydroxybisphenylalkanes such as 2,2-bis (2,4-dihydroxyphenyl) propane; tris (4-hydroxyphenyl) methane, tris (3-methyl-4-hydroxyphenyl) methane, 1,
1,1-tris (4-hydroxyphenyl) ethane,
Polyhydroxytrisphenylalkanes such as [1,1-bis (3-methyl-4-hydroxyphenyl) -1- (4-hydroxyphenyl)] ethane; 1,1,2,
2-tetrakis (4-hydroxyphenyl) ethane,
Polyhydroxytetrakisphenylalkanes such as 1,1,2,2-tetrakis (3-methyl-4-hydroxyphenyl) ethane and 1,1,3,3-tetrakis (4-hydroxyphenylpropane); α, α, α ′, Α′−
Tetrakis (4-hydroxyphenyl) -3-xylene, α, α, α ′, α′-tetrakis (4-hydroxyphenyl) -4-xylene, α, α, α ′, α′-tetrakis (3-methyl-) 4-hydroxyphenyl) -4-
Polyhydroxytetrakisphenyl xylenes such as xylene; cresol novolac resin, resorcin-acetone resin, pyrogallol-acetone resin, polyvinylphenol resin, vinylphenol copolymer, and the like.

Examples of the quinonediazidesulfonic acid ester of the photosensitizer used in the present invention include 1,2-benzoquinonediazide-4-sulfonic acid ester and 1,2-
Naphthoquinonediazide-4-sulfonic acid ester, 1,
2-naphthoquinonediazide-5-sulfonic acid ester,
Examples thereof include o-quinonediazide sulfonic acid esters such as 2,1-naphthoquinonediazide-4-sulfonic acid ester and 2,1-naphthoquinonediazide-5-sulfonic acid ester.

The photosensitizers used in the present invention may be used alone or in admixture of two or more. The compounding amount of the photosensitizer is usually 1 to 100 parts by weight, preferably 3 to 40 parts by weight, based on 100 parts by weight of the alkali-soluble phenol resin. If the amount is less than 1 part by weight, it becomes difficult to form a pattern. If the amount is more than 100 parts by weight, the sensitivity is lowered and the undeveloped portion is liable to occur.

(Monohydroxy Compound) The monohydroxy compound used in the present invention is a compound represented by the above general formula [I], and specific examples thereof include compounds having the following chemical formulas.

[0023]

[Chemical 3]

[0024]

[Chemical 4]

[0025]

[Chemical 5]

[0026]

[Chemical 6]

[0027]

[Chemical 7]

[0028]

[Chemical 8]

[0029]

[Chemical 9]

[0030]

[Chemical 10]

[0031]

[Chemical 11]

[0032]

[Chemical formula 12]

[0033]

[Chemical 13]

[0034]

[Chemical 14]

[0035]

[Chemical 15]

[0036]

[Chemical 16]

[0037]

[Chemical 17]

[0038]

[Chemical 18]

[0039]

[Chemical 19]

By using the hydroxy compound represented by the general formula [I], the exposure margin (exposure latitude) is particularly improved, and a positive resist having a small dimensional change with respect to the exposure amount can be obtained. Also, the balance of sensitivity, remaining film rate, resolution, etc. becomes good.

In the present invention, the compounding amount of the above monohydroxy compound is usually in the range of 1 to 100 parts by weight with respect to 100 parts by weight of the alkali-soluble phenolic resin, and the preferable compounding amount is the composition of the alkali-soluble phenolic resin or Although it varies depending on the molecular weight, the molecular weight distribution, or the type of the photosensitizer, a range of about 3 to 60 parts by weight is suitable. If this blending amount is too small, the effect of the present invention will be insufficient, and conversely, if it is too large, the resolution and heat resistance may decrease.

(Other Components) The resist composition of the present invention is usually used by uniformly dissolving it in a solvent in order to apply it to a substrate to form a resist film. Examples of the solvent include ketones such as acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, cycloheptanone, butyrolactone; alcohols such as n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, t-butyl alcohol; ethylene glycol. Ethers such as dimethyl ether, ethylene glycol diethyl ether, dioxane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Alcohol ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether; esters such as propyl formate, butyl formate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate; 2-oxypropion Methyl acid, ethyl 2-oxypropionate, 2
-Monooxycarboxylic acid esters such as methyl methoxypropionate and ethyl 2-methoxypropionate; cellosolve esters such as cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate; propylene glycol, propylene glycol monomethyl Propylene glycols such as ether, propylene glycol monomethyl ethyl acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol Halogenated hydrocarbons such as trichlorethylene; diethylene glycol such as methyl ethyl ether, toluene, aromatic hydrocarbons such as xylene; dimethylacetamide, dimethyl formamide, N
-Methyl acetamide, polar solvent such as N-methylpyrrolidone; and the like. You may use these individually or in mixture of 2 or more types.

In the resist composition of the present invention, in order to improve developability, storage stability, heat resistance, etc., if necessary, for example, a copolymer of styrene and acrylic acid, methacrylic acid or maleic anhydride is used. Coalescence, copolymers of alkenes and maleic anhydride, vinyl alcohol polymers, vinylpyrrolidone polymers, rosin, shellac and the like can be added. Further, compatible additives such as dyes, surfactants, sensitizers, anti-striation agents, and plasticizers may be contained.

(Developer) An alkaline aqueous solution is used as a developer for the resist composition of the present invention.
Inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, ammonia; ethylamine,
Primary amines such as propylamine; diethylamine,
Secondary amines such as dipropylamine; tertiary amines such as trimethylamine and triethylamine; alcohol amines such as diethylethanolamine and triethanolamine; tetramethylammonium hydroxide,
Quaternary ammonium salts such as tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide; and the like. Furthermore, if necessary, an appropriate amount of a water-soluble organic solvent such as methanol, ethanol, propanol, or ethylene glycol, a surfactant, a storage stabilizer, a resin dissolution inhibitor, or the like can be added to the alkaline aqueous solution.

(Positive Resist Composition) The resist composition of the present invention is applied to the surface of a substrate such as a silicon wafer by a conventional method using the solvent solution thereof, and then the solvent is dried and removed to form a resist film. Can be formed.
As the coating method, spin coating is particularly preferred.

The exposure is performed by a deep ultraviolet irradiation device or krypton /
A fine pattern can be formed by irradiating short wavelength ultraviolet rays or KrF excimer laser light using an excimer laser device in which fluorine gas is sealed. By performing heat treatment (post-exposure bake) after light irradiation, the resolution can be further increased.

[0047]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The parts and% in the examples are by weight unless otherwise specified.

[Synthesis Example 1] Synthesis of novolak resin (A-1) In a 2 liter flask equipped with a cooling tube and a stirrer,
356 g of m-cresol, 356 g of p-cresol, 3
348 g of 7% formalin and 2.4 oxalic acid dihydrate
9 g was charged, and the reaction was performed for 2 hours while maintaining the temperature at 95 to 100 ° C. After that, water is distilled off at 100 to 105 ° C. for 2 hours, and the temperature is further raised to 180 ° C. for 10 to 3
After the pressure was reduced to 0 mmHg to remove unreacted monomer and water, the molten resin was returned to room temperature and recovered to obtain 530 g of novolak resin (A-1). The polystyrene-converted weight average molecular weight of the obtained novolak resin (A-1) by GPC (gel permeation chromatography) is
It was 6900.

Synthesis Example 2 Synthesis of Novolac Resin (A-2) In a 2 liter flask equipped with a cooling tube and a stirrer,
m-cresol 392g, p-cresol 320g, 3
380 g of 7% formalin, and oxalic acid dihydrate 2.4
9 g was charged, and the reaction was performed for 2 hours while maintaining the temperature at 95 to 100 ° C. After this, water is distilled off at 100 to 105 ° C. for 2 hours, and the temperature is further raised to 180 ° C. for 10 to 3
The pressure was reduced to 0 mmHg to remove unreacted monomer and water. After returning to room temperature, 540 g of novolak resin was obtained.
This resin was dissolved by adding 400 g of ethyl cellosolve acetate. Attach the dropping funnel to the flask and adjust the temperature to 80.
Toluene 27 from the dropping funnel while controlling at ~ 90 ° C.
00 g was added dropwise and heating was continued for another hour. The mixture was gradually cooled to room temperature and left standing for 1 hour to precipitate a resin component. The supernatant was removed by decantation, 500 g of ethyl cellosolve acetate was added, and 100 at 100 mmHg.
Residual toluene was removed by heating to ° C to obtain a solution of novolak resin (A-2) in ethyl cellosolve acetate.
The polystyrene reduced weight average molecular weight of this novolak resin (A-2) by GPC was 9,800.

[Synthesis Example 3] Synthesis of Photosensitizer (B-1) 2,3,4,4'-tetrahydroxybenzophenone was used as a compound having an -OH group, and its -OH group was 85.
1,2-naphthoquinonediazide in an amount corresponding to mol%
Dissolve 5-sulfonic acid chloride in dioxane and
It was a 0% solution. While controlling the temperature at 20 to 25 ° C., 1.2 equivalents of triethylamine of 1,2-naphthoquinonediazide-5-sulfonic acid chloride was added dropwise over 30 minutes, and the reaction was completed by maintaining the temperature for 4 hours. ..
The salt that has precipitated is filtered off, and 0.2 times 10 times the amount of the reaction solution.
% Oxalic acid aqueous solution. The precipitated solid content was filtered, washed with ion-exchanged water, and dried to obtain a quinonediazidesulfonic acid ester-based photosensitizer (B-1).

[Synthesis Example 4] Synthesis of Photosensitizer (B-2) Tris (4-hydroxyphenyl) methane was used as a compound having an -OH group, and 1,2-mol corresponding to 85 mol% of the -OH group was used. Naphthoquinone diazide-5-sulfonic acid chloride was dissolved in dioxane to give a 10% solution. After this, the sensitizer (B
-2) was obtained.

[Synthesis Example 5] Synthesis of Photosensitizer (B-3) α, α, α ', α'-tetrakis (p-hydroxyphenyl) -p-xylene was used as a compound having an -OH group. 1,2-naphthoquinonediazide-5-sulfonic acid chloride corresponding to 75 mol% of -OH groups was dissolved in dioxane to obtain a 10% solution. Thereafter, a photosensitizer (B-3) was obtained by the same formulation as in Synthesis Example 3.

Examples 1 to 10 The alkali-soluble phenolic resin having the composition shown in Table 1, the photosensitizer, and the monohydroxy compound were dissolved in ethyl cellosolve acetate,
The amount of solvent used was adjusted so that the coating could be applied to a film thickness of 1.2 μm. In the case of using the novolac resin (A-2), the solid content concentration of the resin solution was measured in advance, and the resin solution was blended and prepared based on the solid content. Pore size 0.1μm
A resist solution was prepared by filtering with a polytetrafluoroethylene filter.

After coating the above resist solution on a silicon wafer with a coater, prebaking was performed at 90 ° C. for 90 seconds to form a resist film having a thickness of 1.17 μm. An i-line stepper NSR1755i7A (manufactured by Nikon Corporation, NA = 0.5) was formed on the silicon wafer on which this resist film was formed.
0) and the test reticle, the exposure was performed while varying the exposure time, and then the post exposure baking was performed at 110 ° C. for 60 seconds. Next, it was developed by a paddle method at 23 ° C. for 1 minute with a 2.38% tetramethylammonium hydroxide aqueous solution to form a positive pattern.

The silicon wafer on which this positive pattern was formed was taken out and observed with an electron microscope to measure the resolution, pattern dimensions, etc., and the resist was evaluated. The results are shown in Table 1. The film thickness of the pattern was measured using a film thickness meter Alpha Step 200 (manufactured by Tenko Co., Ltd.).

The methods of measuring sensitivity, residual film rate, resolution and exposure margin are as follows. <Sensitivity> The exposure time for which a 1: 1 line & space pattern of 0.60 μm can be formed as designed. <Resolution> This represents the limit resolution under the above exposure conditions. <Remaining film ratio> Indicates the ratio of resist film thickness before and after development. <Exposure margin> The relationship between the exposure time and the pattern dimension of 0.60 μm was graphed, the variation of the exposure time that the variation of the pattern dimension could be maintained within the design dimension ± 5% was obtained, and this variation was divided by the sensitivity. It is a value.

[Comparative Examples 1 and 2] Resist solutions were prepared and evaluated in the same manner as in Examples, except that the monohydroxy compound of the present invention was not used. Table 1 shows the composition of the resist and the evaluation results.

[0058]

[Table 1]

[0059]

According to the present invention, a positive resist composition having an excellent balance of various properties such as sensitivity, residual film ratio, resolution and dimensional controllability is provided.

The positive resist composition of the present invention is
It is excellent in so-called exposure margin (exposure latitude), which has a small dimensional change with respect to the exposure amount in fine processing of 1 μm or less.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Fujii 1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa Inside Zeon Corporation R & D Center

Claims (2)

[Claims] 1. (a) Alkali-soluble phenolic resin,
A positive resist composition comprising (b) a quinonediazide sulfonate ester photosensitizer, and (c) a monohydroxy compound represented by the following general formula [I]. [Chemical 1] R _{1 to} R ₅ : each independently a hydrogen atom, a halogen atom,
It is selected from an alkyl group having 1 to 8 carbon atoms and an alkenyl group having 2 to 5 carbon atoms. R ₇ and R ₈ are each independently a hydrogen atom and a carbon number of 1 to
4 alkyl groups. 2. (a) Alkali-soluble phenolic resin 1
00 parts by weight, (b) 1 to 100 parts by weight of a quinonediazide sulfonic acid ester photosensitizer, (c) 1 to 100 parts by weight of the monohydroxy compound represented by the general formula [I], and (d) the above components are dissolved. The positive resist composition according to claim 1, which contains a sufficient amount of a solvent.