JP2000338661A - Positive type resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance resolution without considerable sacrificing other various resist performances by incorporating an alkali-soluble resin, a radiation sensitive component and a low molecular weight alkali-soluble component selected from a specified polyphenol compound and an oligomer containing the polyphenol compound and having a specified weight average molecular weight or below. SOLUTION: The positive type resist composition contains an alkali-soluble resin, a radiation sensitive component and a low molecular weight alkali-soluble component selected from a polyphenol compound of the formula having a molecular weight of <=1,000 and an oligomer containing the polyphenol compound and having a weight average molecular weight of <=1,000. In the formula, R1-R8 are each H, an alkyl or an alkoxy, Q1 and Q2 are each H or an alkyl, (a) and (b) are each 1, 2 or 3, (c) and (d) are each 1 or 2 and (m) and (n) are each an integer of >=1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet ray, a far ultraviolet ray (including an excimer laser, etc.), an electron beam, an ion beam, and an X-ray containing an alkali-soluble resin and a radiation-sensitive component.
The present invention relates to a positive-type radiation-sensitive resist composition suitably used for fine processing of a semiconductor integrated circuit in response to radiation such as radiation.

[0002]

2. Description of the Related Art A lithography process using a resist composition is usually employed for fine processing of a semiconductor integrated circuit.
Generally, it is often used because of its excellent resolution.
Positive resists generally contain an alkali-soluble component and a radiation-sensitive component. Specifically, a novolak resin containing an alkali-soluble novolak resin and a radiation-sensitive quinonediazide compound, which utilizes the fact that the alkali-insoluble quinonediazide compound is decomposed by the action of radiation to generate a carboxyl group and becomes alkali-soluble.
A quinonediazide-based resist is known.

[0003] In recent years, integrated circuits have been miniaturized with higher integration, and submicron pattern formation has been required. As a result, a positive resist composition exhibiting even better resolution is required. For such pattern miniaturization, so-called chemically amplified resists utilizing the chemical amplification effect of an acid generator have been partially adopted, but the demand for novolak / quinonediazide-based resists is still strong.

In order to increase the resolution of the novolak / quinonediazide-based positive resist, it is conceivable to increase the amount of the radiation-sensitive quinonediazide compound. There is a limit that the profile deteriorates and a rectangular pattern shape cannot be obtained. Japanese Patent Application Laid-Open No. 1-105243 discloses that the sensitivity and heat resistance of a resist can be improved by mixing a low molecular weight novolak oligomer obtained by condensing m-cresol with formaldehyde into a novolak resin having a high molecular weight by separation. Examples are shown (Examples 5 and 8 of the publication), and further Japanese Patent Application Laid-Open Nos. 2-2560 and 2-200253.
JP-A Nos. 3-259149 and 5-204144 disclose the sensitivity and resolution by blending a novolak-based trinuclear polyhydric phenol compound with a novolak / quinonediazide-based resist. Improvements are described.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the resolution of a positive resist containing an alkali-soluble resin and a radiation-sensitive component without sacrificing other resist properties. is there. As a result of research, they have found that the resolution can be further improved by adding a certain compound to a positive-working radiation-sensitive resist composition containing an alkali-soluble resin and a radiation-sensitive component, and completed the present invention.

[0006]

That is, the present invention comprises an alkali-soluble resin and a radiation-sensitive component.

[0007]

Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ ,
R ⁶ , R ⁷ and R ⁸ each independently represent hydrogen, alkyl or alkoxy, Q ¹ and Q ² each independently represent hydrogen or alkyl, a and b each independently represent 1,
Represents 2 or 3, c and d each independently represents 1 or 2, m and n each independently represents an integer of 1 or more;
The structure of each of the (m + n) units may be the same or different) and a weight-average molecular weight of 1,000 containing the polyhydric phenol compound having a molecular weight of 1,000 or less and the polyhydric phenol compound represented by the above formula (I). Positive-type composition containing a low-molecular-weight alkali-soluble component selected from the following oligomers (however, the low-molecular-weight alkali-soluble component is not only a compound or oligomer obtained by condensing only m-cresol with formaldehyde): It is intended to provide a radiation resist composition. The weight average molecular weight mentioned here is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the above formula (I), R ¹ , R
² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each hydrogen, alkyl or alkoxy, and Q ¹ and Q ²
Is hydrogen or alkyl, respectively. Here, the alkyl and alkoxy may each have about 1 to 5 carbon atoms, and the alkoxy has 1 to 3 carbon atoms.
A degree is enough. A particularly preferred alkyl is methyl and a particularly preferred alkoxy is methoxy. It is advantageous that Q ¹ and Q ² are each hydrogen from the viewpoint of the raw material.

In the formula (I), a, b, c and d
Represents the number of hydroxyl groups located on each benzene ring, and a and b represent the number of hydroxyl groups located on the benzene rings at both ends.
Can each be 1 to 3, and c and d represent the number of each hydroxyl group located on a plurality of benzene rings at the center.
Can each be 1 or 2, but in general it is advantageous to have one hydroxyl group on each benzene ring, ie a, b, c and d are each 1 .

In the present invention, the polyhydric phenol compound represented by the formula (I) having a molecular weight of 1,000 or less is used as a low molecular weight alkali-soluble component, or the polyhydric phenol represented by the formula (I) is used. An oligomer containing a compound and having a weight average molecular weight of 1,000 or less is used as a low molecular weight alkali-soluble component. Of course, it is also possible to use the polyhydric phenol compound itself and the oligomer together.

First, an embodiment in which the polyhydric phenol compound represented by the formula (I) itself is used as a low molecular weight alkali-soluble component will be described.
It may have four or more benzene rings, ie, tetranuclear or more, but is generally preferably a tetranuclear or pentanuclear compound, ie, a compound in which m + n is 2 or 3. . Particularly advantageous tetranuclear and pentanuclear polyhydric phenol compounds can be represented by the following formulas (II) and (III), respectively.

[0013]

Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R
^6, R ⁷ and R ⁸ are as defined above.

The tetranuclear polyhydric phenol compound represented by the formula (II) includes, for example, 4,4 having a structure of the following formula (IIa):
4'-methylenebis [2- (2-hydroxy-5-methylbenzyl) -3,6-dimethylphenol] and the following formula
4,4'-methylenebis [2-
(4-hydroxybenzyl) -3,6-dimethylphenol] and the like.

[0016]

Further, pentanuclear polyhydric phenol compounds represented by the formula (III) include, for example, 2,6-bis [4-hydroxy-3- (2-hydroxy-) having a structure of the following formula (IIIa): 5-methylbenzyl) -2,5-dimethylbenzyl] -4-methylphenol and the like.

[0018]

Among them, polynuclear phenol compounds having a phenol nucleus derived from p-cresol at both ends,
In particular, p-cresol and xylenol, especially 2,5
Compounds having a structure in which -xylenol is bonded to methylene are advantageous. 4,4'-methylenebis [2- (2-hydroxy-5-methylbenzyl) -3,6-dimethylphenol] having the structure of the above formula (IIa) or the above formula (IIIa)
2,6-bis [4-hydroxy-3- having the structure of
(2-Hydroxy-5-methylbenzyl) -2,5-dimethylbenzyl] -4-methylphenol is one such advantageous compound.

The polyhydric phenol compounds represented by the formula (I) are described, for example, in JP-A-6-167805 and JP-A-9-11409.
It can be manufactured by the method described below according to the description in Japanese Patent Publication No. 3 and the like. That is, the following formula (IV)

[0021]

(Wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ , Q ¹ ,
Q ² , c, d, m and n are as defined above.
And a dihydric alcohol represented by the following formulas (V) and (VI)

[0023]

(Wherein R ¹ , R ² , R ³ , R ⁴ , a and b are as defined above), a method of condensing with a mononuclear phenol compound represented by the following formula (VII):

[0025]

(Wherein R ⁵ , R ⁶ , R ⁷ , R ⁸ , Q ² ,
c, d and m are as defined above) and the following formulas (VIII) and (IX)

[0027]

(Wherein R ¹ , R ² , R ³ , R ⁴ , Q ¹ , a and b are as defined above) by a method of condensing with a monohydric alcohol represented by the formula (I) ) Can be produced. These condensation reactions are usually performed in the presence of an acidic catalyst such as p-toluenesulfonic acid, sulfuric acid, and oxalic acid.

As the polynuclear phenol compound represented by the formula (VII), if there is a commercially available product, it can be used as it is. For example, a mononuclear phenol compound is reacted with an aldehyde, and the mononuclear phenol compound is sequentially connected. Can also be synthesized. Examples of the mononuclear phenol compound as a starting material include phenol, resorcinol, catechol, cresol, xylenol, 2,3,
5-trimethylphenol, methoxyphenol, ethylphenol, 2-methylresorcinol and the like can be mentioned. These can be the mononuclear phenol compounds of the formula (V) or the formula (VI), which are led to the terminal phenol nucleus of the polyhydric phenol compound represented by the formula (I), but may also be trivalent phenols such as pyrogallol. The compound can also be a mononuclear phenol compound corresponding to Formula (V) or Formula (VI). Furthermore, the dihydric alcohol represented by the formula (IV) can be produced by reacting the polynuclear phenol compound represented by the formula (VII) with an aldehyde. Various tetranuclear, pentanuclear, or hexanuclear polyhydric phenol compounds described in JP-A-6-167805 and JP-A-9-114093 are used as low-molecular-weight alkali-soluble components in the present invention. Can be used.

Next, an embodiment in which an oligomer having a weight average molecular weight of 1,000 or less containing the polyhydric phenol compound of the above formula (I) is used as a low molecular weight alkali-soluble component will be described. It can be produced by condensing a mononuclear phenol compound exemplified as a starting material of the polyhydric phenol compound of (I) with an aldehyde, particularly formaldehyde, in the presence of an acid catalyst such as oxalic acid. The reaction conditions at this time are basically the same as those for producing a general novolak resin,
A low-molecular-weight oligomer is obtained by using a small amount of an acid catalyst, for example, about 0.001 to 0.01 mol times based on a mononuclear phenol compound, and shortening the reaction time, for example, to about 1 to 5 hours. be able to.

As the oligomer-type low molecular weight alkali-soluble component in the present invention, it is preferable to use at least two kinds of mononuclear phenol compounds and to condense these with formaldehyde. Above all, it is advantageous that the raw material mononuclear phenol compound contains m- or p-cresol, for example, a combination of m-cresol and p-cresol, m- or p-cresol, 2,3-, 2,5
Combinations with xylenol, such as-, 3,4- or 3,5-xylenol. Particularly preferred are p-cresol and xylenol, especially 2,5
-Combinations with xylenol are included.

The resist composition of the present invention contains the low-molecular weight alkali-soluble component as described above in addition to the alkali-soluble resin and the radiation-sensitive component. What is generally used in this field may be used. Examples of the alkali-soluble resin include polyvinylphenol and novolak resin, and in particular, novolak resin is suitably used. The novolak resin is obtained by condensing a phenolic compound and an aldehyde in the presence of an acid catalyst.

The phenolic compound used for producing the novolak resin includes, for example, phenol, o-, m-
-Or p-cresol, 2,3-, 2,5-, 3,4-
Or 3,5-xylenol, 2,3,5-trimethylphenol, 2-, 3- or 4-tert-butylphenol, 2-tert-butyl-4- or -5-methylphenol, 2-, 4- or 5 -Methylresorcinol, 2-,
3- or 4-methoxyphenol, 2,3-, 2,5-
Or 3,5-dimethoxyphenol, 2-methoxyresorcinol, 4-tert-butylcatechol, 2-, 3-
Or 4-ethylphenol, 2,5- or 3,5-diethylphenol, 2,3,5-triethylphenol,
Polyhydroxytriphenylmethane-based compounds obtained by condensation of xylenol and hydroxybenzaldehyde are exemplified. These phenolic compounds are
Each can be used alone or in combination of two or more.

Aldehydes used in the production of novolak resins include, for example, aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, pivalaldehyde and hexylaldehyde, cyclohexanealdehyde, cyclopentanaldehyde and Cycloaliphatic aldehydes such as furfural, benzaldehyde, o
-, M- or p-methylbenzaldehyde, p-ethylbenzaldehyde, 2,4-, 2,5-, 3,4- or 3,5-dimethylbenzaldehyde, o-, m- or p
-Hydroxybenzaldehyde and o-, m- or p-
Examples include aromatic aldehydes such as anisaldehyde, and araliphatic aldehydes such as phenylacetaldehyde. These aldehydes can also be used alone or in combination of two or more, if desired. Among these aldehydes, formaldehyde is preferably used because it is industrially easily available.

Examples of the acid catalyst used for the condensation of the phenol compound with the aldehyde include inorganic acids such as hydrochloric acid, sulfuric acid, perchloric acid and phosphoric acid, formic acid, acetic acid, oxalic acid, trichloroacetic acid and p-toluenesulfonic acid. Organic acids, such as
And divalent metal salts such as zinc acetate, zinc chloride and magnesium acetate. These acid catalysts can also be used alone or in combination of two or more. The condensation reaction is performed according to a conventional method, for example, at 60 to 120 ° C.
For about 2 to 30 hours.

The novolak resin obtained by condensation is preferably subjected to an operation such as fractionation to reduce the amount of low molecular weight resin. Specifically, the novolak resin is GP
When analyzed by C, the area ratio in the range of molecular weight of 1,000 or less should be 25% or less, and more preferably 20% or less, based on the entire pattern area excluding unreacted phenolic compounds. preferable. Here, the pattern area is 2
It means a value measured using a 54 nm UV detector, and the molecular weight is a value using polystyrene as a standard. When performing separation, a novolak resin is used as a good solvent, for example, alcohols such as methanol and ethanol, acetone and methyl ethyl ketone, ketones such as methyl isobutyl ketone, glycol ethers such as ethyl cellosolve, and ethyl cellosolve acetate. Such as glycol ether esters or ethers such as tetrahydrofuran, and then pouring this solution into water to precipitate high molecular weight components, or mixing this solution with a poor solvent such as pentane, hexane, or heptane. Then, a method of performing liquid separation can be adopted.

As the radiation-sensitive component, a quinonediazide compound, specifically, an o-quinonediazidesulfonic acid ester of a compound having a phenolic hydroxyl group is used. Preferred are 1,2-naphthoquinonediazide-5- or -4-sulfonic acid esters or 1,2-benzoquinonediazide-4-sulfonic acid esters of polyhydroxy compounds having at least three phenolic hydroxyl groups. Such radiation-sensitive quinonediazide compounds can be used alone or in combination of two or more.

These esters can be produced by reacting the above compound having a phenolic hydroxyl group with o-quinonediazidesulfonic acid halide in a suitable solvent in the presence of a base such as triethylamine. After the reaction, an appropriate quinonediazidesulfonic acid ester can be obtained by performing an appropriate post-treatment. For example, a method in which a reaction mass is mixed with water to precipitate a target substance, filtration, and a method of obtaining in powder form by drying, or a resist solvent such as 2-heptanone is added to the reaction mass, washed with water, and separated, There is a method of removing the reaction solvent by distillation or equilibrium flash distillation to obtain a resist solvent solution. Equilibrium flash distillation is a type of continuous distillation operation in which a part of a liquid mixture is evaporated, the generated vapor phase and the liquid phase are brought into sufficient contact, and when equilibrium is reached, a gas is formed. This is a distillation method that separates liquids. Evaporation efficiency is very good, evaporation occurs almost instantaneously, and the gas phase and the liquid phase reach an equilibrium state immediately. Because it requires less time, it is suitable for concentrating heat-sensitive substances.

In the present invention, the polyhydric phenol compound represented by the above formula (I) and / or the oligomer containing the polyhydric phenol compound in addition to the alkali-soluble resin and the radiation-sensitive component as described above, It is blended as a molecular weight alkali-soluble component. In particular, as described above, a high effect is exhibited by using a novolak resin reduced in low molecular weight as an alkali-soluble resin and adding the low molecular weight alkali-soluble component according to the present invention to this. In addition to the low-molecular-weight alkali-soluble component specified in the present invention, an alkali-soluble phenolic compound having a molecular weight of 1,000 or less can be used in combination as an additional low-molecular-weight alkali-soluble component. The alkali-soluble phenolic compound used in combination preferably has at least two phenolic hydroxyl groups in the molecular structure. For example, JP-A-2-75955, JP-A-2-2-2560, JP-A-3-191351 The ones described in the gazette are exemplified. Further, it is of course possible to use a low molecular weight compound or oligomer obtained by condensing only m-cresol, which is excluded from the essential components of the present invention, with formaldehyde as an additional low molecular weight alkali-soluble component.

In the resist composition of the present invention, although it depends on the type of the resist, generally, the radiation-sensitive composition is used for 100 parts by weight of the alkali-soluble component, that is, the alkali-soluble resin and the low-molecular-weight alkali-soluble component in total. The components are used in a range of about 10 to 100 parts by weight. The preferred content of the radiation-sensitive component is about 10 to 50 parts by weight based on 100 parts by weight of the alkali-soluble component. The low-molecular-weight alkali-soluble component is 3% based on the total amount of the alkali-soluble resin and the low-molecular-weight alkali-soluble component.
It is preferred to be present in the range of 〜40% by weight. Furthermore, it is advantageous that the polyhydric phenol compound of the formula (I) or the oligomer containing the same as defined in the present invention accounts for at least 10% by weight of the low molecular weight alkali-soluble component.

The resist composition of the present invention essentially contains the alkali-soluble resin, the radiation-sensitive component and the low-molecular-weight alkali-soluble component described above, but if necessary, a resin other than the alkali-soluble resin. Also, a small amount of various additives commonly used in this field, such as a dye and a surfactant, may be contained. It is also effective to add an alkali-decomposable compound, for example, an acid generator which is decomposed by the action of an alkali developer to generate an acid as proposed in JP-A-10-213905. The inclusion of such an alkali-decomposable compound can contribute to the improvement of the pattern profile.

Each of the above components is dissolved in a solvent to form a resist solution, and is applied to a substrate such as a silicon wafer by a method such as spin coating according to a conventional method. The solvent used here may be any as long as it dissolves each component, has an appropriate drying rate, and gives a uniform and smooth coating film after evaporation of the solvent, and is commonly used in this field. be able to. For example, glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, glycols such as ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether and propylene glycol monoethyl ether. Ethers, esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate, acetone,
Examples include ketones such as methyl isobutyl ketone, 2-heptanone and cyclohexanone, and cyclic esters such as γ-butyrolactone. These solvents are
Each can be used alone or in combination of two or more.

The resist film applied and dried on the substrate is irradiated with radiation for patterning and, if necessary, subjected to post-exposure baking.
Developed with an alkaline developer. The alkaline developer used here may be any of various alkaline aqueous solutions known in the art, but generally, tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline )) Is often used.

[0044]

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, percentages, parts and ratios representing the content or the use amount are based on weight unless otherwise specified. The weight average molecular weight is a value measured by GPC using polystyrene as a standard.

Reference Example 1 (Production of Novolak Resin) A 5-liter four-necked flask equipped with a reflux tube, a stirrer and a thermometer was charged with m- / p having an m-cresol content of 61.6%.
702.1 g of mixed cresol, 379.p-cresol.
2 g, oxalic acid dihydrate 25.5 g, 90% acetic acid aqueous solution 33
7.9 g, 1,008 g of methyl isobutyl ketone and water 1
23 g was charged and the temperature was raised to 80 ° C., and 492.9 g of a 37% aqueous formaldehyde solution was added dropwise over 1 hour. Thereafter, the temperature was raised to the reflux temperature, and in this state, the temperature was maintained for 12 hours. The obtained reaction solution was diluted with methyl isobutyl ketone, washed with water and dehydrated to obtain a novolak resin of 40.
A methyl isobutyl ketone solution containing 1% was obtained. 200 g of this resin solution was charged into a 5-liter bottomed flask,
The mixture was diluted with 335 g of methyl isobutyl ketone, further charged with 412 g of heptane, stirred at 60 ° C., allowed to stand, and separated. The lower novolak resin solution was diluted with 2-heptanone and then concentrated to obtain a solution containing 26.0% of novolak resin.
A heptanone solution was obtained. This novolak resin is referred to as resin A1. The weight average molecular weight of this resin is about 9,800, GP
The area ratio in the range of the molecular weight of 1,000 or less in the C pattern was about 3.8%.

Reference Example 2 (Production of Another Novolak Resin) A 5-liter four-necked flask equipped with a reflux tube, a stirrer and a thermometer was charged with m- / p having an m-cresol content of 61.6%.
1,448.3 g mixed cresol, p-cresol 3
8.62 g, 35.11 g of oxalic acid dihydrate, 464.4 g of a 90% aqueous acetic acid solution, 1,386 g of methyl isobutyl ketone and 169.23 g of water were charged, and the temperature was raised to 80 ° C., where 711. 2 g was added dropwise over 1 hour. Thereafter, the temperature was raised to the reflux temperature, and in this state, the temperature was maintained for 12 hours. The obtained reaction solution was diluted with methyl isobutyl ketone, washed with water and dehydrated to obtain a methyl isobutyl ketone solution containing 43.3% of a novolak resin. 2,487.4 g of this resin solution was charged into a bottomed container, diluted with 6,129.0 g of methyl isobutyl ketone,
Further, 5,572.5 g of heptane was charged and the mixture was stirred at 60 ° C., allowed to stand still, and separated. The lower layer novolak resin solution was
After diluting with heptanone and concentrating, novolak resin was
A 2-heptanone solution containing 3.82% was obtained. This novolak resin is referred to as resin A2. The weight average molecular weight of this resin is about 7,900, and the molecular weight in the GPC pattern is 1,000.
The area ratio in the following range was about 4.5%.

Reference Example 3 (Production of m-cresol / formaldehyde novolak oligomer) In a 3-liter four-necked flask equipped with a reflux tube, a stirrer, and a thermometer, 1.081 g of m-cresol and oxalic acid dihydrate 2 were placed. After charging 0.52 g, the temperature was raised to 80 ° C., and 242.2 g of 37% aqueous formaldehyde solution was added dropwise over 1 hour. Thereafter, the temperature was raised to the reflux temperature, and the temperature was maintained for 3 hours in this state. The resulting reaction solution was concentrated by heating to 110 ° C. under a reduced pressure of 200 torr.
The mixture was heated to 145 ° C under reduced pressure and concentrated. This is 2-
After dilution with heptanone, washing and concentration, a 2-heptanone solution containing 36.1% of a novolak oligomer was obtained. This oligomer had the following structure (where p represents the number of repetitions commensurate with the degree of polymerization), and had a weight average molecular weight of about 510. This is designated as oligomer BX.

[0048]

Reference Example 4 (Production of p-cresol / 2,5-xylenol / formaldehyde novolak oligomer) p-cresol 73.0 was placed in a 200 ml four-necked flask.
g, 2,5-xylenol 27.26 g and oxalic acid dihydrate 0.227 g were charged, and the temperature was raised to 60 ° C. while stirring. There was a 36% 53% formaldehyde aqueous solution.
g was added dropwise over 20 minutes, the temperature was further raised to the reflux state, and the temperature was maintained for 4 hours. The obtained reaction solution was concentrated by heating to 110 ° C. under a reduced pressure of 200 torr.
The mixture was heated to 145 ° C under reduced pressure and concentrated. 120 g of 2-heptanone was charged and dissolved in the concentrated mass at room temperature, and washed with 60 g of ion-exchanged water four times. 40 squares after washing
The pressure was reduced to torr, the temperature was raised to 80 ° C., and dehydration was performed. As a result, 104.11 g of a 2-heptanone solution containing 58.12% of a novolak oligomer was obtained. This oligomer is
Each unit of the following formula is bonded with methylene, and the terminal is p-cresol or 2,5-xylenol unit,
Its weight average molecular weight was about 750. This is designated as oligomer B1.

[0050]

Reference Example 5 (Production of m-cresol / p-cresol / formaldehyde novolak oligomer) In a 200 ml four-necked flask, m-cresol 73.
0 g, p-cresol 73.0 g and oxalic acid dihydrate 0.3
4 g was charged and heated to 60 ° C. while stirring. 32.84 g of a 38% formaldehyde aqueous solution was added dropwise thereto over 1 hour, and the temperature was further raised to a reflux state and maintained for 4.5 hours. Thereafter, post-processing is performed in the same manner as in Reference Example 4,
92.46 g of a 2-heptanone solution containing 60.59% of a novolak oligomer was obtained. In this oligomer, each unit of the following formula was bonded with methylene, and the terminal was an m-cresol or p-cresol unit, and the weight average molecular weight was about 680. This is designated as oligomer B2.

[0052]

Reference Example 6 (Production of m-cresol / 2,5-xylenol / formaldehyde novolak oligomer) In a 200 ml four-necked flask, 73.0 m-cresol was added.
g, 2,5-xylenol 27.26 g and oxalic acid dihydrate 0.227 g, and the temperature was raised to 60 ° C. while stirring. There was a 21.92% aqueous 39% formaldehyde solution.
g was added dropwise over 30 minutes, the temperature was further raised to the reflux state, and the temperature was maintained for 4.5 hours. Thereafter, post-treatment was carried out in the same manner as in Reference Example 4 to obtain a solution containing 57.16% of a novolak oligomer 2
74.80 g of heptanone solution were obtained. In this oligomer, each unit of the following formula was bonded with methylene, and the terminal became m-cresol or 2,5-xylenol unit, and the weight average molecular weight was about 490. This is designated as oligomer B3.

[0054]

Examples 1 to 6 and Comparative Example 1 Novolak resin A1 obtained as in Reference Examples 1 and 2
And A2 in a solids ratio of 5/95 or 2.5 / 97.
Resin A11 and Resin A1 having the following physical properties
Each solution of No. 2 was used.

Resin A11: A1 / A2 = 5/95, weight average molecular weight of about 7,950, and area ratio of about 4.4% in a GPC pattern having a molecular weight of 1,000 or less. Resin A12: A1 / A2 = 2.5 / 97.5, weight average molecular weight about
7,930, about 4.5% area ratio in the range of molecular weight 1,000 or less in GPC pattern.

As the radiation-sensitive component, the following formula

[0058]

4- (7-hydroxy-) having the structure
A condensate of (2,4,4-trimethyl-2-chromanyl) resorcinol and 1,2-naphthoquinonediazide-5-sulfonic acid chloride in a molar ratio of 1: 2.6 was used.

Further, as the low molecular weight alkali-soluble component (1), the oligomer BX, which is obtained in Reference Examples 3 to 6 and which will be described again below,
And B1 to B3, and polynuclear polyhydric phenol compounds C1 to C3 shown below were used.

BX: m-cresol / formaldehyde novolak oligomer obtained in Reference Example 3 (weight average molecular weight: about 510). B1: p-cresol / 2,5-xylenol / formaldehyde novolak oligomer obtained in Reference Example 4 (weight average molecular weight: about 750). B2: m-cresol / p-cresol / formaldehyde novolak oligomer obtained in Reference Example 5 (weight average molecular weight: about 680). B3: m-cresol / 2,5-xylenol / formaldehyde novolak oligomer obtained in Reference Example 6 (weight average molecular weight: about 490). C1: 4,4'-methylenebis [2- (2-hydroxy-5-methylbenzyl)-having the structure of the above formula (IIa)
3,6-dimethylphenol]. C2: 2,6-bis [4- having the structure of the above formula (IIIa)
Hydroxy-3- (2-hydroxy-5-methylbenzyl) -2,5-dimethylbenzyl] -4-methylphenol. C3: 4,4'-methylenebis [2- (4-hydroxybenzyl) -3,6-dimethylphenol] having the structure of the above formula (IIb).

Further, as another low molecular weight alkali-soluble component (2), the following formula

[0063]

4- (1 ', 2', 3 ',
4 ', 4'a, 9'a-Hexahydro-6'-hydroxyspiro [cyclohexane-1,9'-xanthene]-
4'a-yl) resorcinol was used.

Each of these components was mixed with a solvent in the following composition and dissolved.

Novolak resin (solid content and type are described in Table 1) 9.73 parts Radiation-sensitive component 3.5 parts Low molecular weight alkali-soluble component (1) (solid content and type are described in Table 1) 1.0 part Low molecular weight alkali soluble component (2) 3.6 parts solvent: 2-heptanone 25.5 parts ^* ethyl lactate 25.5 parts ^* 2-heptanone comprises bringing component from the resin solution and oligomer solution.

Each solution was filtered through a fluororesin filter to prepare a resist solution, and the resist solution was spin-coated on a silicon wafer treated with hexamethyldisilazane, and placed on a direct hot plate at 90 ° C. for 60 seconds. Was performed to form a resist film having a thickness of 1.06 μm. An i-line stepper [NSR-20 manufactured by Nikon Co., Ltd.]
05 i9C ”, NA = 0.57, σ = 0.60], and the line and space pattern was exposed by changing the exposure stepwise. Then, the post-exposure was performed on a hot plate at 110 ° C. for 60 seconds. 2.38 after jar bake
60% aqueous solution of tetramethylammonium hydroxide
Second paddle development was performed. The pattern after development was observed with a scanning electron microscope, and the effective sensitivity and resolution of each pattern were evaluated as follows. The results are shown in Table 1.

Effective sensitivity: 1.00 μm The line and space pattern was displayed at an exposure amount at which the sectional width became 1: 1.

Resolution: The minimum line width of the line and space pattern separated by the exposure amount of the effective sensitivity was displayed.

[0070]

[Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example No. Resin Low molecular weight alkali-soluble component (1) Effective sensitivity Resolution ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 1 A11 C1 0.5 part + BX 0.5 part 65 msec 0.50 μm 〃 2 A11 C2 0.5 part + BX 0.5 part 70 msec 0.475 μm 〃 3 A11 C3 0.5 part + BX 0.5 part 60 msec 0.525 μm 〃 4 A12 B1 1.0 part 51 msec 0.55 μm 〃 5 A12 B2 1.0 part 48 msec 0.55 μm ６ 6 A12 B3 1.0 part 48 msec 0.525μm ─────────────────────────────── Comparative example A11 BX 1.0 part 50 msec 0.575μm ━━━━━━━ ━━━━━━━━━━━━━━━━━━━━━━━━

As shown in Table 1, the resolution of the embodiment is higher than that of the comparative example.

[0072]

As described above, the positive resist composition of the present invention is excellent in resolution and in balance of various resist properties such as profile, sensitivity, heat resistance and depth of focus.
Therefore, this composition is effective for further miniaturization of a semiconductor integrated circuit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Li Saho, 3-1-198 Kasuganaka, Konohana-ku, Osaka Sumitomo Chemical Co., Ltd. F-term (reference) 2H025 AA02 AB16 AC01 AC04 AC05 AC06 AC07 AC08 AD03 BE00 BE01 CB29 CB45 CB52 CB55 CC20 4J002 CC051 CC061 EQ036 EV246 FD206 GP03 GQ05 4J033 CA01 CA02 CA12 CA29 HA02 HA07 HA08 HA12 HB10

Claims (12)

[Claims] (1) The composition contains an alkali-soluble resin and a radiation-sensitive component, and further comprises the following formula (I) (Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent hydrogen, alkyl or alkoxy, and Q ¹ and Q ² each independently A and b each independently represent 1, 2 or 3, c and d each independently represent 1 or 2, m and n each independently represent 1 or 2 And the structure of each of the (m + n) units may be the same or different), and a polyhydric phenol compound having a molecular weight of 1,000 or less and a polyhydric phenol compound represented by the above formula (I) Low molecular weight alkali-soluble component selected from oligomers having a weight average molecular weight of 1,000 or less (however, the low molecular weight alkali-soluble component is not only a compound or oligomer obtained by condensing only m-cresol with formaldehyde) Specially containing A positive-type radiation-sensitive resist composition. 2. The composition according to claim 1, wherein Q ¹ and Q ² in the formula (I) are each hydrogen. 3. The composition according to claim 1, wherein a, b, c and d in the formula (I) are each 1. 4. The composition according to claim 1, wherein the low-molecular-weight alkali-soluble component contains a polyhydric phenol compound wherein m + n in the formula (I) is 2 or 3. 5. The low-molecular-weight alkali-soluble component is represented by the following formula (II):
Or (III) (Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are as defined in claim 1). The composition according to claim 1, comprising a phenol compound. 6. A polyhydric phenol compound having a structure in which p-cresol and xylenol are bonded with methylene,
The composition according to claim 5, which has a phenol nucleus derived from cresol at both ends. 7. The polyhydric phenol compound is 4,4'-methylenebis [2- (2-hydroxy-5-methylbenzyl) -3,6-dimethylphenol] or 2,6-bis [4-hydroxy-3 The composition according to claim 5, which is-(2-hydroxy-5-methylbenzyl) -2,5-dimethylbenzyl] -4-methylphenol. 8. The composition according to claim 1, wherein the low-molecular-weight alkali-soluble component contains an oligomer obtained by condensing at least two kinds of mononuclear phenol compounds with formaldehyde. 9. The composition according to claim 8, wherein the mononuclear phenol compound as a raw material of the oligomer contains m- or p-cresol. 10. The composition according to claim 9, wherein the mononuclear phenol compound is m-cresol and p-cresol. (11) the mononuclear phenol compound is m- or p-
The composition according to claim 9, which is cresol and xylenol. 12. The alkali-soluble resin is a novolak resin, and when analyzed by gel permeation chromatography, it has a molecular weight of 1,000 based on polystyrene as a standard.
The composition according to any one of claims 1 to 11, wherein the area ratio in the following range is 25% or less based on the total pattern area excluding the unreacted raw material phenolic compound.