JPH02173748A - Radiation sensitive resin composition - Google Patents

Abstract

PURPOSE:To improve heat resistance and dry etching resistance and to obtain the resin compsn. which is adequate as a positive type resist having high resolution and high sensitivity by incorporating an alkaline soluble novolak resin having sulfonic acid or sulfonate and a 1, 2-quinone diazide compd. into the compsn. CONSTITUTION:This compsn. contains the alkaline soluble novolak resin having the sulfonic acid or sulfonate and the 1, 2-quinone diazide compd. The alkaline soluble novolak resin having the sulfonic acid or sulfonate used for this resin compsn. is obtd. by bringing a phenolic compd. contg. a sulfonated phenolic compd. as its essential component and a carbonyl compd. into poly-condensation. The high sensitivity as the positive type resist is obtd. in this way and the resist patterns having the high resolution are formed. In addition, the resulted resist patterns are excellent in heat resistance and dry etching resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radiation-sensitive resin composition, and particularly to a radiation-sensitive resin composition suitable as a positive resist for producing integrated circuits.

(Prior Art) Conventionally, resists used to fabricate integrated circuits include negative resists made of cyclized rubber mixed with a bisazide compound, and alkali-soluble novolak resin mixed with a 1.2-
A positive resist containing a quinonediazide compound is known.

In negative resists, the radiation-irradiated areas become insoluble in the developer and remain, forming a resist pattern, but the resist pattern swells significantly in the developer made of organic solvent, resulting in low resolution of the resist pattern. It has the following drawback.

On the other hand, in a positive resist, a pattern is formed by the radiation-exposed area being solubilized in a developer and the non-irradiated area remaining, but in general, a positive resist is made of an alkali-insoluble novolak resin. 1
．． Since it contains a 2-quinonediazide compound, it is difficult to dissolve in a developer consisting of an alkaline aqueous solution, and the formed pattern hardly swells. Therefore, there is an advantage that the non-irradiated portion, which becomes the resist pattern, is faithful to the pattern of the mask and high resolution can be achieved.

Now, in recent years, there has been a demand for further improvement in the degree of integration of integrated circuits, and positive resists with excellent resolution have come to be used frequently. Furthermore, efforts to increase the degree of integration of integrated circuits are not limited to improvements in resist materials, but are also being made in methods of etching substrates through resist patterns. As a link to this, the etching method has been changed from the conventionally mainstream wet etching method to a dry etching method.

[Problem to be solved by the invention]

However, since the dry etching method etches the substrate with reactive ions, the temperature of the substrate rises, causing thermal deformation of the resist pattern and reducing dimensional accuracy. It is known that it can be damaged by ions, etc. In this regard, although the conventional positive resists are evaluated to have higher heat resistance and dry etching resistance than other resists, they are still not fully satisfactory. is expected to improve. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a radiation-sensitive resin composition suitable for use as a positive resist, which has further improved heat resistance and dry etching resistance, and has high resolution and high sensitivity.

[Means to solve the problem]

The present invention solves the above-mentioned problems by providing a radiation-sensitive resin composition (hereinafter referred to as "resin composition).

The alkali-soluble novolak resin containing sulfonic acid or sulfonate (hereinafter referred to as "sulfonated novolac") used in the resin composition of the present invention is preferably (A
) It is obtained by a method of polycondensing a phenol compound containing a sulfonated phenol compound as an essential component and (B) a carbonyl compound. According to this method, the content of sulfonic acid or sulfonate can be easily adjusted.

The phenol compound as component (A) used in the above method contains a sulfonated phenol compound as an essential component, but it must be a mixture of the sulfonated phenol compound and a phenol compound that does not have sulfonic acid or sulfonate. is preferred.

Examples of the sulfonated phenol compound include compounds represented by the following general formulas (1) and (I[).

[Here, R1 is a hydrogen atom, a halogen atom, a hydroxyl group,
Hydrocarbon group, alkoxy group, alkoxycarbonyl group,
Arylcarbonyl group, alkyloxy group, arylcarbonyl group, alkyloxy group, arylcarbonyl group, alkyloxy group,
loyloxy group, acyl group, cyano group or nitro group,
X means a hydrogen atom, ammonium ion] H [Here, R1 and X are as described above] Specific examples of R1 in general formulas (I) and (II) include a hydrogen atom, a hydroxyl group, a cyano group and In addition to nitro groups, halogen atoms such as chlorine atoms, fluorine atoms, and bromine atoms;
Alkyl groups such as methyl group, ethyl group, propyl group, butyl group, aryl groups such as phenyl group, toluene group, cumenyl group, alkenyl groups such as vinyl group, propenyl group, allyl group, butenyl group, benzyl group, phenethyl group , a hydrocarbon group such as an aralkyl group such as a cumyl group; a methoxy group,
Examples include alkoxy groups such as ethoxy, propoxy, and butoxy; acyl groups such as acetyl, propionyl, butyryl, and valeryl.

Among the sulfonated phenol compounds represented by general formulas (1) and (I[), particularly preferred are those in which R1 is a hydrogen atom, an alkyl group, or an aryl group.

Specific examples of the sulfonated phenol compound represented by the above general formula (1) include 0-phenolsulfonic acid, m
-phenolsulfonic acid, p-phenolsulfonic acid,
2-methylphenol 4-sulfonate, 3-methylphenol 4-sulfonate, 2-ethylphenol 4-sulfonate, 3-ethylphenol 4-sulfonate, 2-7' 4-sulfonate Examples include phenol, 4-sulfonic acid-3-butylphenol, ammonium 0-phenolsulfonate, ammonium m-phenolsulfonate, ammonium p-phenolsulfonate, and the like. Specific examples of the sulfonated phenol represented by formula (■) include 2-sulfonic acid-1-naphthol, 3-sulfonic acid-1-naphthol, 4-sulfonic acid-1-naphthol, and 5-sulfonic acid-1-naphthol. Acid-1-naphthol, 2-methyl-5-sulfonic acid-1-naphthol, 2-
Methyl-4-sulfonic acid-1-naphthol, 2-ethyl-
4-sulfonic acid-1-naphthol, 2-butyl-4-sulfonic acid-1-naphthol, 2-acetoxy-4-sulfonic acid-1-naphthol, 1-acetoxy-4-sulfonic acid-2-naphthol, 2- Methoxy-4-sulfonic acid-1-naphthol, 1-methoxy-4-sulfonic acid-2
-Naphthol, 2-methoxycarbonyl-4-sulfonic acid-1-naphthol, 2-acetyl-4-sulfonic acid-
1-naphthol, 2-ammonium sulfonate-1-naphthol, 3-ammonium sulfonate-1-naphthol, 4-ammonium sulfonate-1-naphthol, 5
-Ammonium sulfonate-1-naphthol, 2-methyl-5-ammonium sulfonate-1-naphthol, 2
-Methyl-4-ammonium-1-naphthol sulfonate, ammonium-1-naphthol 2-ethyl-4-sulfonate, and the like. Among these, preferred are P-phenolsulfonic acid, m-phenolsulfone, ammonium 10-phenolsulfonate, and m-phenolsulfonic acid.
Ammonium phenolsulfonate, ammonium p-phenolsulfonate, 2-methyl-4-sulfonic acid-
1-naphthol, 2-methyl-5-sulfonic acid-1-naphthol, 2-methoxy-4-sulfonic acid-1-naphthol, ammonium 2-sulfonate-1-naphthol,
Examples thereof include 3-ammonium sulfonate-1-naphthol, 4-ammonium sulfonate-1-naphthol, and 5-ammonium sulfonate-1-naphthol.

These sulfonated phenol compounds alone have 2
Can be used in combination of more than one species.

Furthermore, in order to improve the polymerization conversion rate, these sulfonated phenol compounds are preferably used in the form of sulfonate salts.

Further, examples of the phenol compound having no sulfonic acid or sulfonic acid salt include compounds represented by the following general formulas (III) and (IV).

H [In C, the plurality of R1s may be the same or different, as described above] In the general formulas (III) and (IV), R1 is preferably a hydrogen atom, a hydroxyl group, an alkyl group, an aryl group,
These include an alkoxycarbonyl group or an acyl group.

Specific examples of the phenolic compound having no sulfonic acid or sulfonate represented by the general formula (I[I) and the formula (IV) include α-naphthol, β-naphtholphenol, 0-cresol, m-cresol , p-cresol, 0-ethylphenol, m-ethylphenol, p-ethylphenol, 0-butylphenol, m-
Butylphenol, p-butylphenol, 3,5-xylenol, 2.4-xylenol, 2.5-xylenol, 3.4-xylenol, 2,3.5-trimethylphenol, 0-phenylphenol, p-phenylphenol , isopropenylphenol, 0-tolylphenol, p-)ruylphenol, 0-styrylphenol, p-styrylphenol, O-cinnamylphenol, p-cinnamylphenol, 0-acetoxyphenol, m-acetoxyphenol, p-acetoxy Phenol, 〇-benzoyloxyphenol, m-benzoyloxyphenol, P-benzoyloxyphenol,
〇-methoxyphenol, m-methoxyphenol, p
-methoxyphenol, 0-methoxycarbonylphenol, m-methoxycarbonylphenol, P-methoxycarbonylphenol, 0-acetylphenol, m
-acetylphenol, p-acetylphenol, p-
Examples include hydroxydiphenyl. Among these, preferred are phenol, 0-cresol, m
-Cresol, P-cresol, 2,5-xylenol, 34-xylenol, 3,5-xylenol, 2,3
．． Examples thereof include 5-trimethylphenol, ot-butylphenol, m-t-stilphenol, pt,-butylphenol, p-hydroxydiphenyl, and the like.

These phenolic compounds without sulfonic acid or sulfonate can be used alone or in combination of two or more.

When a sulfonated phenol compound and a phenol compound without a sulfonic acid or sulfonate are used together, the molar ratio of sulfonated phenol compound/phenol compound without a sulfonic acid or sulfonate is 1/ 99-50150 is preferable, especially 1/99-50150
40/60 is preferred. If this ratio is less than 1/99, the dry etching resistance, resolution and heat resistance of the resulting resin composition will not be sufficiently improved.

Examples of the carbonyl compound used as the component (B) in the above method for producing a sulfonated novolac include a compound represented by the following formula (V).

[Here, the plurality of R2s may be the same or different, and mean a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, or an aralkyl group. ] Specific examples of the alkyl group, aryl group, alkenyl group, and aralkyl group represented by R2 in general formula V) include those exemplified for R1 in formula (1).

- Examples of the carbonyl compound represented by formula (V) include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde,
Phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, tolylbenzaldehyde, mesitylbenzaldehyde, phenethylbenzaldehyde, 0-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, 0-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde,
0-nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, 0-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, p-
Aldehydes such as n-7' tylbenzaldehyde, acrolein, crotonaldehyde, cinnamaldehyde;
Examples include ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl phenyl ketone, and methyl benzyl ketone.

Among these, formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, acrolein, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, methyl phenyl ketone, methyl benzyl ketone and the like are preferred.

These carbonyl compounds can be used singly or in combination of two or more.

The carbonyl compound as component (B) is preferably used in an amount of 0.7 to 2 moles, particularly preferably 0.7 to 1.5 moles, per mole of the phenol compound as component (A). When this ratio is less than 0.7 mol, the remaining amount of unreacted phenol compound increases, resulting in a low softening point of the resulting sulfonated novolak, and when it exceeds 2 mol, the sulfonated novolac tends to gel.

The polycondensation of the phenol compound as component (A) and the carbonyl compound as component (B) is usually carried out using an acid catalyst. Examples of the acid catalyst include inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid, and organic acids such as formic acid, oxalic acid, and acetic acid. The amount of this acid catalyst used is usually I X 10-7 to 5 X 10-7 per mole of the phenol compound of component (A).
'mole, preferably 1X10-' to 5 x 10 moles.

In the polycondensation of component (A) and component (B), no reaction medium may be used, but water, a hydrophilic solvent, etc., can also be used as the reaction medium. Examples of hydrophilic solvents used in this case include alcohols such as methanol, ethanol, propatool, and butanol, ethers such as tetrahydrofuran, dioxane, and diglyme, esters such as ethyl acetate, propyl acetate, and butyl acetate, or acetonitrile. Nitriles such as propionitrile and butyronitrile are mentioned. The amount of these reaction media to be used is usually 1 to 1 of the phenol compound of component (A).
5000 parts by weight or less, preferably 10 parts by weight per 00 parts by weight
~1000 parts by weight.

If it exceeds 5000 parts by weight, the reaction will be slow.

The reaction temperature in polycondensation is appropriately selected depending on the reaction raw materials, but is usually 10 to 200"C1, preferably 60 to 1
It is 60°C. If the reaction temperature is less than 10°C, the reaction is slow, and if it exceeds 200°C, the resulting sulfonated novolac tends to gel.

The polycondensation of component (A) and component (B) is preferably carried out under pressure in a closed system filled with an inert gas, such as nitrogen gas, helium gas, argon gas, etc., and is usually carried out under pressure. The difference is 1-50 kg/c+Il, preferably 3-25 kg/c-.

After the completion of polycondensation, in order to remove unreacted raw materials, acid catalyst, and reaction medium present in the system,
The temperature is increased to ~230"C and the volatiles are removed under reduced pressure to recover the sulfonated novolak.

Furthermore, after the completion of polycondensation, the reaction product can be precipitated by dissolving the reaction system in the hydrophilic solvent and adding it to a large amount of a precipitant such as water, n-hexane, petroleum ether, or n-hebutane. , sulfonated novolacs can also be recovered.

The sulfonated novolac used in the present invention may be a sulfonated novolac resin obtained by condensing the carbonyl compound with the phenol compound that does not have the sulfonic acid or sulfonate salt.

Furthermore, the resin composition of the present invention may also contain a novolac resin obtained by condensing the carbonyl compound with the phenol compound that does not have the sulfonic acid or sulfonate salt.

Hereinafter, the sulfonated novolak and other novolak resins that can be used in combination with the sulfonated novolak will be collectively referred to as alkali-soluble novolak resins.

The content of sulfonic acid or sulfonate in the alkali-soluble novolak resin is preferably 1 to 2.
0% by weight, particularly preferably 1 to 15% by weight.

Examples of the 1,2-quinonediazide compound which is the second essential component used in the resin composition of the present invention include (poly) such as P-cresol, resorcinol, and pyrogallol.
1,2-penzoquinonediazide of hydroxybenzene
4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, or 1,2-naphthoquinonediazide-5-sulfonic acid ester; 214-dihydroxyphenyl-propyl ketone, to 2,4-dihydroxyphenyl-n- xyl ketone, 2.4-dihydroxybenzophenone, 2,3.4-) lyhydroxyphenyl-n-hexyl ketone, 2.3.4-) lyhydroxybenzophenone, 2.3.6-1-lyhydroxybenzophenone, 2.2', 4.4'-tetrahydroxybenzophenone, 2,3.4.4'-tetrahydroxybenzophenone, 2.2', 3.4.6'
-pentahydroxybenzophenone, 2.3.3',
1 of (poly)hydroxyphenylalkyl ketones or (poly)hydroxyphenylaryl ketones such as 4.4', 5'-hexahydroxybenzophenone, 2.2', 3.4.4'6'-hexahydroxybenzophenone, etc. , 2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester or l,2-naphthoquinonediazide-5-
Sulfonic acid ester; bis(p-hydroxyphenyl)
Methane, bis(2,4-dihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)methane, 2,2-bis(p-hydroxyphenyl)propane,
2.2-bis(2,4-dihydroxyphenyl)propane, 2.2-bis(2,3,4=trihydroxyphenyl)propane and other bis[(poly)hydroxyphenyl coalkanes such as 1,2- Benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-
Sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester; 3,5-dihydroxybenzoic acid lauryl, 2,3.4-1-lihydroxybenzoic acid M phenyl, 3,4.5-)lihydroxybenzoic acid 1 of (poly)hydroxybenzoic acid alkyl esters or (poly)hydroxybenzoic acid aryl esters such as propyl acid, 3.4.5-phenyl trihydroxybenzoate
．． 2-benzoquinonediazide-4-sulfonic acid ester, 1.2-naphthoquinonediazide-4-sulfonic acid ester or 1. 2-naphthoquinonediazide-5-sulfonic acid ester; bis(2,5-dihydroxybenzoyl)methane, bis(2,3,4-)dihydroxybenzoyl)methane, bis(2,4,6-trihydroxybenzoyl)methane, Bis[(polymer) such as p-bis(2,5-dihydroxybenzoyl)benzene, p-bis(2,3,4-trihydroxybenzoyl)benzene, )
bitroxybenzoyl corekane or bis[(poly)
1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester or 1,2-benzoquinonediazide-4-sulfonic acid ester of benzene (bitroxybenzoyl)
- Naphthoquinone diazide-5-sulfonic acid ester: (poly)ethylene glycol rouge such as ethylene glycol (3,5-dihydroxybenzoate), polyethylene glycol rouge (3,4,5-1-dihydroxybenzoate) [(poly)hydroxybenzoate ] No. 1.
2-benzoquinonediazide-4-sulfonic acid ester,
1,2-naphthoquinonediazide-4-sulfonic acid ester or 1,2-naphthoquinonediazide-5-sulfonic acid ester; furthermore, "Light" by J. Kosar.
-Sensitive Systems” 339~
352 (1965), John Wiley & 5
ons (New York), W, S, De For
est author “Photoesist” 50 (1975
), MeGraw-1 (ill, Inc, (New
York), and 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, on the hydroxyl group of an alkali-soluble novolac resin, as described in JP-A-58-17112. 1.2-naphthoquinonediazide-4-sulfonyl chloride or 1.2-benzoquinonediazide-4
Examples include resins in which -sulfonyl chloride is condensed at an equivalent ratio of 0.001 to 0.5.

These 1,2-quinonediazide compounds may be used alone or in combination of two or more.

In the resin composition of the present invention, this 1,2-quinonediazide compound is added to the alkali-soluble novolank resin 100
Usually 5 to 100 parts by weight, preferably 1 part by weight
0 to 50 parts by weight are used.

When the amount is less than 5 parts by weight or more than 100 parts by weight, it becomes difficult to form a resist pattern by radiation irradiation and development.

The resin composition of the present invention is prepared, for example, by dissolving the alkali-soluble novolac resin and the 1,2-quinonediazide compound in required amounts in a suitable solvent and mixing them.

Examples of solvents used in this case include glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, cellosolve esters such as metal cellosolve acetate and ethyl cellosolve acetate, ketones such as methyl ethyl ketone and cyclohexanone, or ethyl acetate. , butyl acetate, methyl lactate, ethyl lactate, and other esters. These solvents can be used alone or in combination of two or more. Furthermore, aromatic hydrocarbons such as toluene and xylene, ethers such as benzyl alcohol and dihexyl ether, glycol ethers such as diethylene glycol monomethyl ether and diethylene glycol monomethyl ether, ketones such as acetonyl acetone and isophorone, caproic acid, Fatty acids such as caprylic acid, alcohols such as 1-octatool, 1-nonanol, and benzyl alcohol, esters such as benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, ethylene carbonate, propylene carbonate, and phenyl cellosolve acetate. Alternatively, a high boiling point solvent such as lactones such as T-butyrolactone and δ-valerolactone may be added.

When the resin composition of the present invention is used, for example, as a resist, the resin composition prepared as described above is applied to a substrate such as a silicon wafer by spin coating,
It is applied by methods such as flow coating and roll coating.

Furthermore, a sensitizer can be added to the resin composition of the present invention in order to improve the sensitivity as a resist. Examples of this sensitizer include 2H-pyrido(3,2-b)
-1,4-oxazine-3[4H3ones, 101(-
Pyrido(3,2-b) (1,4]-benzothiazines, urazoles, hydantoins, barbyls,
Glycine anhydride 1 1Hydroxybenzotriazurs, alloxanes, maleimides, etc. can be mentioned. The amount of the sensitizer blended is usually 100 parts by weight or less per 100 parts by weight of the 1,2-quinonediazide compound.

Furthermore, the resin composition of the present invention may contain a surfactant. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; Nonionic surfactants such as oxyethylene alkyl phenyl ethers and polyethylene glycol dialkyl esters such as polyethylene glycol dilaurate and polyethylene glycol distearate, FTOP EF30 L
EF303, EF352 (product name manufactured by Shinjuyo Kasei Co., Ltd.),
Megafac F171, F172, F173 (product name manufactured by Dainippon Ink Co., Ltd.), Florado FC430, FC4
31 (product name manufactured by Jujutsu 3M), Asahi Guard AG
710, Surf +: +7sc 10h SCI O2,
5C103, 5C104, 5C105, 5C106, S
Fluorine surfactants such as -382 (trade name manufactured by Asahi Glass Co., Ltd.), organosiloxane polymer KP341 (trade name manufactured by Shin-Etsu Chemical Co., Ltd.), and acrylic acid or methacrylic acid type (co-)
Examples include polymers o-No., 75, No. 95 (trade name, manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.). The blending amount of these surfactants is usually 2 parts by weight or less per 100 parts by weight of the solid content of the resin composition of the present invention.

Furthermore, the resin composition of the present invention may also contain storage stabilizers, colorants, etc., if necessary.

In addition, in order to improve the adhesive strength between the coating film of the resin composition of the present invention and the substrate, hexamethyldisilazane, chloromethylsilane, etc. can be applied to the substrate in advance.

When using the resin composition of the present invention as a positive resist, e.g., sodium hydroxide, potassium hydroxide, sodium carbonate J1, sodium silicate, sodium metasilicate, aqueous ammonia, etc. inorganic alkalis, primary amines such as ethylamine and n-propylamine, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and methyldiethylamine, and dimetal ethanol. Alcohol amines such as amines and triethanolamine,
- Quaternary ammonium salts such as methylammonium hydroxide, choline, pyrrole, piperidine, 1.
An alkaline aqueous solution in which cyclic amines such as 8-diazabicyclo(5,4,0)-7-undecene and 1,5-diazabicyclo(4,3,0)-5-nonane are dissolved is used. Furthermore, methanol is added to the alkaline aqueous solution.
An aqueous solution containing an appropriate amount of a water-soluble organic solvent such as ethanol or acetone or a surfactant can also be used as the developer.

After developing with the developer, the film is rinsed with water and dried.

[Example] Synthesis Example 1 In a flask, 127 g of phenol, 54 g of p-t-butylphenol, and 1 portion of ammonium p-phenolsulfonate
7g, (phenol/pt, -butylphenol/p
-Ammonium phenolsulfonate = 75/2015
(molar ratio)], 131 g of a 337% by weight aqueous formaldehyde solution, and 0.08 g of oxalic acid, and while stirring, the flask was placed in an oil bath and reacted for 4 hours while maintaining the internal temperature at 100°C.

Thereafter, the oil bath temperature was raised to 150° C., and at the same time the pressure inside the flask was reduced to remove unreacted phenol, pt-7′ tilphenol, ammonium P-phenolsulfonate and formaldehyde, as well as water and oxalic acid.

The molten sulfonated novolac was then returned to room temperature and recovered.

The yield of the sulfonated novolanc was 202 g, and the amount of polycondensation of p-phenolsulfonic acid was 8.6% by weight.

Synthesis Example 2 158 g of rn-cresol, 18 g of p-cresol in a flask [m-cresol/p-cresol = 89.8
/10.2C molar ratio)], 12'5 g of a 337% by weight aqueous formaldehyde solution, and 0.06 g of oxalic acid, and while stirring, the internal temperature was maintained at 100°C and reacted for 3 hours. After the reaction is complete, pour the reaction system into a large amount of water,
The reaction product was precipitated. Then, the precipitate was collected and 4
Vacuum drying was performed at 0°C for 24 hours to obtain a novolak resin.

The yield of the novola-ink resin was 180 g.

Example 1 10 g of sulfonated novolak obtained in Synthesis Example 1 and (2
,4-dihydroxyphenyl)methane-1゜2-naphthoquinonediazide-5-sulfonic acid tetraester 2.5
g was dissolved in 37.5 g of propylene glycol monoethyl ether acetate) and filtered through a filter with a pore size of 0.2 μm to prepare a solution of the resin composition of the present invention.

The obtained solution was spin-coated onto a siliran wafer having a silicon oxide film using a spinner, and then prebaked at 90° C. for 2 minutes to form a resist film with a thickness of 1.0 μm.

Next, wavelength 43 is transmitted through a pattern mask for resolution testing.
After irradiation with ultraviolet rays mainly 6nn+, development was performed for 60 seconds with a 1% by weight tetramethylammonium hydroxide aqueous solution and rinsed with water to form a resist pattern.

As a second result, the resist pattern with a line width of 0.8 μm faithfully reproduced the pattern mask, and the resolution was good.

The silicon wafer having this resist pattern was placed on a real plate for 5 minutes, and the temperature of the real plate and the state of thermal deformation of the resist pattern were observed. When the maximum temperature at which the resist pattern does not deform is defined as the heat resistance temperature, the heat resistance temperature of this product was 150°C, indicating extremely good heat resistance.

Furthermore, the silicon wafer having a resist pattern was attached to a parallel plate type plasma etching apparatus (electrode spacing 40 mm), and the output was 100 W, tetrafluoromethane/oxygen [
9515 (capacity ratio)] and a gas pressure of 15 pa, the dry etching resistance of the resist pattern was examined. As a result, the selectivity ratio of the resist pattern (the ratio of the rate at which the silicon oxide film is etched to the rate at which the resist pattern is etched) was as high as 4.0, and the dry etching resistance was excellent. .

Comparative Example 1 Using the novolac resin obtained in Synthesis Example 2, a solution of a resin composition was prepared in the same manner as in Example 1 except for the above. Using this solution, a resist pattern was formed in the same manner as in Example 1, except that development was performed for 60 seconds with a 2% by weight tetramethylammonium hydroxide aqueous solution. As a result, the minimum line width of the resist pattern that faithfully reproduced the pattern mask was 1.2 μm. Furthermore, the heat resistance temperature of the obtained resist pattern was as low as 110°C.

Examples 2 to 5 Sulfonated novolaks were obtained in the same manner as in Example 1 except that the phenol compound having no sulfonic acid group, the sulfonated phenol compound, and the carbonyl compound shown in Table 1 were used, and the other conditions were the same as in Synthesis Example 1. A solution of the resin composition of the present invention was prepared. A resist L-pattern was formed using this solution in the same manner as in Example 1, and then the resist pattern was examined for its heat resistance, resolution, and dry etching resistance. The results are shown in Table 1.

[Effects of the Invention] The resin composition of the present invention has high sensitivity as a positive resist and can form a high-resolution resist I pattern, and the resulting resist pattern has good heat resistance and dry etching resistance. It is excellent. Therefore, the resin composition of the present invention can be used in a highly efficient manner using radiation such as electron beams, molecular beams, X-rays, gamma rays, ultraviolet rays with a wavelength of 365 nm, ultraviolet rays with a wavelength of 436 mm, deep ultraviolet rays, synchrotron radiation, proton beams, excimer lasers, etc. It is suitable for microfabrication of microprocessors, and can meet the recent demands for further integration of integrated circuits.

Claims (1)

[Claims] A radiation-sensitive resin composition comprising an alkali-soluble novolac resin having a sulfonic acid or a sulfonic acid salt and a 1,2-quinonediazide compound.