JPH03142468A - Positive type resist composition - Google Patents

Abstract

PURPOSE:To prevent pattern peeling phenomenon by using novolak resin having a specified structure in a resist compsn. CONSTITUTION:Resin (I) is synthesized by condensing m-cresol and 2-tert-butyl-6- methylphenol with aldehydes in the presence of an acid catalyst. Formaldehyde, acetoaldehyde and glyoxal may be used as the aldehydes. An org. or inorg. acid or a divalent metallic salt may be used as the catalyst. The molar ratio between the m-cresol and the 2-tert-butyl-6-methylphenol is 95:5-60:40, preferably 95:5-70:30. When a positive type resist compsn. is obtd. by using a compd. represented by the formula as alkali-soluble resin in the case where the area of a part having <=6,000mol.wt. (expressed in terms of polystyrene) in the resin I is regulated to <=65% of the total area of a GPC pattern and the area of a part having <=900mol.wt. to <=30%, pattern peeling phenomenon is prevented. In the formula, each of R1-R3 is 1-5C alkyl or alkoxy, each of l-n is an integer of 0-3 and R' is H.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a positive resist composition that is sensitive to radiation such as ultraviolet rays, deep ultraviolet rays (including excimer radiation, etc.), electron beams, ion beams, and X-rays. It is about things.

<Prior art and problems with the invention> In recent years, integrated circuits have become increasingly finer due to higher integration.
Submicron pattern formation is now required, and positive resists with excellent resolution are required.

Traditionally, a mask contact method has been used to form integrated circuits, but this method is said to have a limit of 2 μm.
As an alternative to this, a reduction projection exposure method is attracting attention. This method is a method in which the pattern of a master mask (reticle) is reduced and projected using a lens system for exposure, and the resolution can be down to submicrons. However, one of the problems with this reduction projection exposure method is that the throughput is low. That is, unlike the conventional batch exposure method such as the mask contact method, the reduction projection exposure method uses divided and repeated exposure, resulting in a problem that the total exposure time per wafer becomes long.

The most important way to solve this problem is to improve the sensitivity of the resist used, as well as improving the equipment. If exposure time can be shortened by increasing sensitivity, throughput and yield can be improved. On the other hand, L.S.
As the integration degree of I increases, the width of wiring becomes finer, and therefore dry etching has become mainstream instead of conventional wet etching. Because of this dry etching, heat resistance of the resist has become more required than before.

Looking at the positive resists currently used from this point of view, they are not necessarily satisfactory in terms of sensitivity, resolution, and heat resistance. -Positive resists have lower sensitivity than negative resists, and improvements are desired.

For example, in order to achieve high sensitivity, the simplest method is to lower the molecular weight of the novolak resin used in positive resists, which increases the rate of dissolution in alkaline developers and increases the apparent sensitivity of the resist. . However, with this method, film loss in non-exposed areas increases (so-called reduction in residual film rate), pattern shape deteriorates, and the difference in dissolution rate in developer between exposed and non-exposed areas becomes small. In addition to problems such as a decrease in the so-called γ value (deterioration in resolution), this also causes a very serious disadvantage in that the heat resistance of the resist decreases. That is, at present, there is no positive resist that has all of sensitivity, resolution, and heat resistance, and we are in an extremely disadvantageous situation in which an attempt to improve one will worsen the other.

In addition, conventional resist compositions have poor adhesion to substrates used for integrated circuit devices, such as silicon dioxide, silicic acid glass, silicon nitride, and aluminum. When exposed to light, some parts of the exposed pattern may disappear.

An object of the present invention is to solve the problems of the prior art for use in the production of integrated circuits, and to provide a positive resist composition that has a good balance of sensitivity, resolution, and heat resistance, and in particular does not cause pattern peeling. It's about doing.

<Specific Means for Solving the Problems> The present inventors have completed the present invention by discovering that the above problems can be solved by using a novolac resin having a specific structure in a resist composition. The present invention is characterized in that it contains an alkali-soluble resin whose essential component is a resin (I) obtained by condensing m-cresol and 2-tert-butyl-6-methylphenol with an aldehyde, and a 1,2-quinonediazide compound. The present invention provides a positive resist composition.

Resin (1) is synthesized by condensing m-cresol and 2-tert-butyl-6-methylphenol with aldehydes in the presence of an acid catalyst.

This condensation reaction is usually carried out at 60 to 120°C for 2 to 30 hours.

Examples of the aldehydes used here include formaldehyde, paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β
-Phenylpropylaldehyde, O-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, glutaraldehyde, glyoxal, 0-methylbenzaldehyde, p-methylbenzaldehyde, etc. Among these compounds, formaldehyde is especially industrially This is preferable because it is easy to handle. These aldehydes can be used alone or in combination with
Can be used in combination of more than one species.

As the catalyst, organic or inorganic acids, divalent metal salts, etc. are used. Specific examples include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid, p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, formic acid, zinc acetate, magnesium acetate, and the like.

Further, the reaction may be carried out in bulk or an appropriate solvent may be used. The molar ratio of m-cresol and 2-tert-butyl-6-methylphenol is preferably 95:5 to 60:40, more preferably 95:5 to 70:30. If the molar ratio of m-cresol exceeds 95%, it will be easily soluble in a developer, making buttering difficult; if it is less than 60%, the solubility in the developer will decrease, making development difficult.

An alkali-soluble resin other than resin (I) can be added to the alkali-soluble resin as long as it does not impair the characteristics of the present invention. In this case, the other alkali-soluble resin used is, for example, polyvinylphenol or novolak. etc. Novolak means, for example, phenol, 0
-cresol, m-cresol, p-cresol, 2.
5-xylenol, 3.5-xylenol, 3.4-xylenol, 2,3.5-)trimethylphenol 4-t
-butylphenol, 2-t-butylphenol, 3-
Phenols such as t-butylphenol, 3-ethylphenol, 2-ethylphenol, 4-ethylphenol, 2-naphthol, 1,3-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, etc. alone or Examples include resins in which two or more types are combined and condensed with formalin by a conventional method.

In particular, the resin (1) is one whose area ratio of polystyrene equivalent molecular weight of 6000 or less to the total area of the GPC pattern is 65% or less, and the area ratio of 900 or less to 30% or less by fractionation after condensation reaction as resin (1). When using, it is preferable to use a compound of formula (n) or a low molecular weight novolac having a polystyrene equivalent weight average molecular weight of 2000 to 200 as the alkali-soluble resin.

R' (R3)ノOH (wherein R+, Rz, Rs represent an alkyl group of C+ to Cs or an alkoxy group of C, -CS, and j!,
mn is an integer from 0 to 3, and R' represents a hydrogen atom or a Cl-C5 alkyl group. ) As the compound represented by formula (II), a compound represented by the following formula is preferably used.

H 0H The polyphenol compound of general formula (n) is synthesized by condensing a phenol compound with a carbonyl compound in the presence of an acid catalyst.

Examples of the phenolic compounds used here include:
Phenol, 0-cresol, m-cresol, p-cresol, 3.5-xylenol 2.5-xylenol, 2.3-xylenol 2.4-xylenol, 2,6
-xylenol 3.4-xylenol, 2,3.5-)
Limethylphenol, 4-t-butylphenol, 2-
t-butylphenol, 3-t-butylphenol, 4
-methoxyphenol, 3-methoxyphenol, 2-
Methoxyphenol, 2,3-dimethoxyphenol,
2.5-dimethoxyphenol, 3.5-dimethoxyphenol, 3-ethylphenol, 2-ethylphenol, 4-ethylphenol, 2.3.5-triethylphenol 3.5-diethylphenol, 2.5-diethylphenol , 2. Examples include 3-diethylphenol. These compounds may be used alone or in combination of two or more.

Examples of the carbonyl compound used in this condensation reaction include benzophenones such as benzaldehyde, O-hydroxybenzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, 3-methoxy-4-hydroxybenzaldehyde, and O-hydroxybenzaldehyde.
Examples include acetophenones such as hydroxyacetophenone, m-hydroxyacetophenone, and p-hydroxyacetophenone.

Further, examples of the acid catalyst used in this condensation reaction include organic acids, inorganic acids, and divalent metal salts.

Specific examples include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid, p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, formic acid, zinc acetate, zinc chloride, and magnesium acetate.

The amount of the carbonyl compound used is preferably 0.02 to 3 mol per mol of the phenol compound, and the amount of the acid catalyst used is preferably 0.01 to 067 mol per mol of the carbonyl compound. The condensation reaction is usually carried out at 30 to 250°C for 2 to 30 hours. Further, the reaction may be carried out in bulk or an appropriate solvent may be used. Examples of the solvent used in this case include water, alcohols, ethyl cellosolve acetate, ethyl cellosolve, ethyl cellosolve, methyl isobutyl ketone, methyl ethyl ketone, hexane, cyclohexane, heftane, benzene, toluene, xylene, and the like. The amount of these solvents is preferably 10 to 500 parts by weight per 100 parts by weight of the total N of the phenolic compound and carbonyl compound.

After the condensation product is demetallized, it can be purified by recrystallization or reprecipitation.

Demetallization can be carried out by dissolving the product in an organic solvent that is separated by mixing it with water, and washing with ion-exchanged water. Examples of the organic solvent include methyl in butyl ketone, ethyl cellosolve acetate, ethyl acetate, and the like.

Demetallization can also be carried out by mixing the product with water, separating the product, dissolving it in an organic solvent, and charging it into ion-exchanged water (re-precipitation). Here, examples of the organic solvent include methanol, ethanol, acetone, and the like. This method is preferable because demetal ionization and purification can be performed simultaneously.

The low molecular weight novolac (III) used in the present invention is synthesized by condensing a phenolic compound with an aldehyde in the presence of an acid catalyst.

Examples of the phenolic compounds used here include:
Phenol, 0-cresol, m-cresol, p-cresol, 3.5-xylenol 2.5-xylenol, 2.3-xylenol 2.4-xylenol, 216
-xylenol 3.4-xylenol, 2.3.5-)
Limethylphenol, resorcinol, etc. are mentioned.

Among them, cresol is preferred. These compounds may be used alone or in combination of two or more, taking into consideration the solubility in an alkaline developer.

Examples of the aldehydes used in this condensation reaction include formalin, paraformaldehyde, acetaldehyde, and glyoxal. Among these, formalin is particularly preferred because it is easily available industrially as a 37% aqueous solution.

As the acid catalyst used in this condensation reaction, organic acids, inorganic acids, divalent metal salts, etc. are used.

Specific examples include oxalic acid, hydrochloric acid, sulfuric acid, perchloric acid, p-)
Examples include luenesulfonic acid, trichloroacetic acid, phosphoric acid, formic acid, zinc acetate, and magnesium acetate. The condensation reaction is usually carried out at 30 to 250°C for 2 to 30 hours. Further, the reaction may be carried out in bulk or an appropriate solvent may be used.

The molecular weight of the low molecular weight novolac (DI) is 2000 to 200, more preferably 1000 to 200, in terms of polystyrene equivalent weight average molecular weight. When the molecular weight exceeds 2000, the sensitivity of the resist composition decreases. Furthermore, if the molecular weight is lower than 200, the adhesion to the substrate, heat resistance, etc. will deteriorate, which is not preferable.

The molecular weight of the low molecular weight novolac (III) can be easily adjusted by adjusting the molar ratio of aldehydes to phenolic compounds. In order to synthesize the above-mentioned novolak having a weight average molecular weight of 2000 to 200 in terms of polystyrene, for example, in the case of m-cresol-formaldehyde resin, the molar ratio of formaldehyde to m-cresol is set to 0.65 to 0.05, and the condensation reaction is performed. You can get it by doing. Further, after performing the condensation reaction, it is more preferable to remove residual monomers by distillation or the like.

Polyphenol compound (II) or low molecular weight novola
The total amount of alkali-soluble resin, i.e., the total amount of resin (I), polyphenol (n) or low molecular weight novolak (III), and other alkali-soluble resins, is 1.
00 parts by weight, preferably 4 to 50 parts by weight. Polyphenol compound (II) or low molecular weight/borac (I
If II) is less than 4 parts by weight, the solubility in a developer consisting of an alkaline aqueous solution will be reduced, making development difficult; if it exceeds 50 parts by weight, even areas not exposed to radiation will be easily dissolved in the developer. Buttering becomes difficult.

The resin (1) having a polystyrene equivalent molecular weight of 6000 or less can be obtained by fractionation or the like.

As for the separation method, the synthesized novolak resin is used as a good solvent, such as alcohols (methanol, ethanol, etc.).
Ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ethylene glycol and its ethers, ether esters (ethyl cellosol, ethyl cellosolve acetate, etc.), a method of dissolving in tetrahydrofuran, etc., and then adding water to precipitate, or heptane. There is a method of separating the resin by placing it in hexane, pentane, cyclohexane, etc. The weight average molecular weight of the resin thus obtained is preferably 20,000 to 3,000 in terms of polystyrene.

Next, 1 and 2 used in the positive resist composition of the present invention
- The quinonediazide compound is not particularly limited, but for example, 1,2-benzoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-4-sulfonic acid ester, 1,2-naphthoquinonediazide-5-sulfonic acid ester, etc. can be mentioned. These esters can be obtained by a known method, for example, by condensing 1,2-naphthoquinonediazide sulfonic acid chloride or benzoquinonediazide sulfonic acid chloride with a compound having a hydroxyl group in the presence of a weak alkali.

Examples of compounds having a hydroxyl group include hydroquinone, resorcinol, phloroglycin, 2.4-
Dihydroxybenzophenone, 2゜3.4-) dihydroxybenzophenone, 2,34.4゛-tetrahydroxybenzophenone, 2.2',4.4'-tetrahydro5, xybenzophenone, bis(p-hydroxyphenyl)methane, bis (2,4-dihydroxyphenyl>methane, bis(2,3,4-)dihydroxyphenyl)methane, 2,2-bis(p-hydroxyphenyl)
Examples include propane, 2,2-bis(2,4-dihydroxyphenyl)propane, 2,2-bis(2,3°4-trihydroxyphenyl)propane, and oxyflavans. Among them, 1,2-quinonediazide compound has 2.3
．． 4.4°-tetrahydroxybenzophenone or oxyfura (where q represents a number from 0 to 4, r represents a number from 1 to 5, and q+r is 2 or more. R1, R3, R6 are Representing a hydrogen atom, an alkyl group, an alkenyl group, a cyclohexyl group, or an aryl group), a 1,2-naphthoquinonediazide-5-sulfonic acid ester in which an average of two or more hydroxyl groups are esterified is preferably used. . These 1,2-quinonediazide compounds may be used alone or in combination of two or more. A positive resist composition is prepared by adding the 1,2-quinonediazide compound and resin (I) and optionally a polyphenol compound (II) or a low molecular weight novolak (I).
This is carried out by mixing and dissolving an alkali-soluble resin containing II) etc. in an appropriate solvent. The ratio of the alkali-soluble resin to the 1,2-quinonediazide compound is usually 5 to 100 parts by weight, preferably 10 to 50 parts by weight, per 100 parts by weight of the alkali-soluble resin.

If this amount is less than 5 parts by weight, it will easily dissolve in a developer consisting of an alkaline aqueous solution, making buttering difficult. If it exceeds 100 parts by weight, short-term radiation irradiation will cause the added 1,2-quinonediazide compound to become soluble. It is not possible to decompose everything, and as a result, the amount of radiation irradiation must be increased, resulting in a decrease in sensitivity. The solvent used is preferably one that evaporates at an appropriate drying rate and provides a uniform and smooth coating film. Such are: ethyl cellosolve acetate, methyl cellosolve acetate, ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether acetate, butyl acetate,
Examples include methyl isobutyl ketone and xylene. These solvents may be used alone or in combination of two or more. The positive resist composition obtained by the above method (in addition, a small amount of resin, dye, etc. may be added as an additive if necessary).

<Effects of the Invention> The positive resist composition of the present invention has a better balance of performance than existing resist compositions, and in particular does not cause the phenomenon of pattern disappearance during exposure.

<Examples> Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Synthesis Example 1 In a Mitsuro flask with an internal volume of 1000 rn1, 229.8 g of m-cresol, 61.6 g of 2-tert-butyl-6-methylphenol (molar ratio 85/15), 252 g of ethyl cellosolve acetate, and 30.0 g of 5% oxalic acid.
Add 4 g and heat in a 100℃ oil bath while stirring.
Formalin aqueous solution (37.0%) 180.2 g 40
The mixture was added dropwise over several minutes, and then the reaction was continued with stirring for 14 hours. Thereafter, the mixture was neutralized, washed with water, and dehydrated to obtain a solution of novolak resin in ethyl cellosolve acetate. The weight average molecular weight in terms of polystyrene determined by GPC was 4,100.

Synthesis Example 2 The same procedure as Synthesis Example 1 was performed except that the reaction time was changed.
An ethyl cellosolve acetate solution of novolac resin was obtained. The weight average molecular weight in terms of polystyrene by GPC is 2
It was 850.

Synthesis Example 3 An ethyl cellosolve acetate solution of novolac resin was obtained by carrying out the same operation as in Synthesis Example 1 except that the molar ratio of m-cresol and 2-tert-butyl-6-methylphenol was 90:10. The weight average molecular weight in terms of polystyrene by GPC was 5950, the surface orientation with a polystyrene equivalent molecular weight of 6000 or less was 65.7%, and the surface orientation with a polystyrene equivalent molecular weight of 900 or less was 25°5%.

Synthesis Example 4 The same procedure as Synthesis Example 1 was carried out except that the molar ratio of m-cresol and 2-tert-butyl-6-methylphenol was changed to 87.5:12.5, and a solution of novolac resin in ethyl cellosolve acetate was prepared. Obtained. The weight average molecular weight in terms of polystyrene determined by GPC was 8,000.

Synthesis Example 5 Ethyl cellosolve acetate solution of the novolac resin obtained in Synthesis Example 1 (novolac resin content 41.94%)
) 155.3g into a bottomless separable flask of IF, and then add 170.4g of ethyl cellosolve acetate.
g and 1 g of normal heptane at 20°C.
After stirring for 0 minutes, the mixture was allowed to stand and the liquid was separated. Normal heptane in the lower layer obtained by liquid separation is removed using an evaporator,
An ethyl cellosolve acetate solution of novolac resin was obtained.

Polystyrene equivalent weight average molecular weight by GPC is 580
0, the surface orientation with a polystyrene equivalent molecular weight of 6000 or less is 59.3%, and the surface orientation with a polystyrene equivalent molecular weight of 900 or less is 19.0
%Met.

Synthesis Examples 6 to 8 Almost the same operations as in Synthesis Example 5 were performed to obtain the resins shown in Table 1 in some cases.

Table 1 Synthesis Example 9 5 equipped with a stirrer, cooling tube, water separator, and thermometer
00mf! 2.5-xylenol 1 in a Mitsuro flask
34.0 g, salicylaldehyde, 33.7 gp-)) toluenesulfonic acid, 0.83 g, and) toluene, 268 g, were charged, and the mixture was reacted for 16 hours at 115° C. with heating and stirring in an oil bath while removing condensed water. By filtering the reaction mixture at 50 to 60°C, a crude cake of the triphenylmethane derivative represented by the following formula (a) is obtained. The crude cake was melted in 580 g of methanol at 20 to 25 DEG C., charged to 1450 g of an ion exchange resin, filtered and dried to obtain 89.3 g of a fine cake of the following formula (a). Yield 93.0% (based on salicylaldehyde).

Melting point 274-275°C Synthesis Example 1O m-cresol 2 in a Mitsuro flask with an internal volume of 1000-
70 g of 1% oxalic acid and 48.7 g of formalin aqueous solution (37.0%
) 60.8 g was added dropwise over 40 minutes, and the reaction was further carried out with stirring for 2 hours. Thereafter, the mixture was neutralized, washed with water, and dehydrated to obtain a solution of novolak resin in ethyl cellosolve acetate.

Polystyrene equivalent weight average molecular weight by GPC is 330
Met.

Synthesis Example 11 149 g of m-cresol, 121 g of 5p-cresol, 252 g of ethyl cellosolve acetate, and 30.4 g of 5% oxalic acid were placed in a Mitsuro flask with an internal volume of 1000 rni, and while heating and stirring in an oil bath at 90°C, a formalin aqueous solution (37.0 %) was added dropwise over 40 minutes, and the reaction was further carried out with stirring for 7 hours. Thereafter, the solution was neutralized, washed with water, and dehydrated to obtain a solution of 2 liters of novolac in ethyl cellosolve acetate. The weight average molecular weight in terms of polystyrene determined by GPC was 9,600.

Synthesis Example 12 Ethyl cellosolve acetate solution of the novolac resin obtained in Synthesis Example 11 (novolac resin content 41.2%)
) into a 311 bottomless separable flask, and then add 868.8 g of ethyl cellosolve acetate.
and 544.6g of normal heptane and heated to 30℃ at 20℃.
After stirring for a minute, the mixture was allowed to stand and the liquid was separated. Normal heptane in the lower layer obtained by liquid separation was removed using an evaporator to obtain a solution of novolak resin in ethyl cellosolve acetate. The weight average molecular weight in terms of polystyrene by GPC is 15
It was 500. By this fractionation method, 7% of the polystyrene equivalent molecular weight was 900 or less.

Examples 1 to 5 and Comparative Examples 1 to 2 The novolak resins obtained in Synthesis Examples 1 to 8 and 11.12 were combined with a photosensitizer and optionally the compound obtained in Synthesis Example 9 or the compound obtained in Synthesis Example 10. A resist solution was prepared by dissolving a low molecular weight novolak in ethyl cellosolve acetate with the composition shown in Table 2.

The amount of solvent was adjusted to give a film thickness of 1.28 μm under the coating conditions shown below. Each of these compositions was filtered through a 0.2 μm Teflon filter to prepare a resist solution.

This was coated on a silicon wafer cleaned by a conventional method using a spin coater at 4000 r/p/rn. Next, this silicon wafer was baked for 1 minute on a vacuum adsorption type hot plate at 100°C. Thereafter, using a reduction projection exposure apparatus using a 350 W ultra-high pressure mercury lamp as a light source, exposure was performed by changing the exposure time step by step for each shot. After exposure, it was observed using an optical microscope whether part of the pattern had disappeared. Then, development was performed using developer 5OPD (trade name, manufactured by Sumitomo Chemical Co., Ltd.). After rinsing and drying, the amount of film loss and exposure time for each shot was plotted to determine the sensitivity. Further, the remaining film rate was determined from the remaining film thickness of the unexposed area.

In addition, silicon wafers with resist patterns after development were placed in a clean oven set at various temperatures for 30 minutes.
The resist pattern was left in an air atmosphere for 1 minute, and then the resist pattern was observed with a scanning electron microscope to evaluate heat resistance.

These results are summarized in Table 2. As is clear from Table 2, the performance balance of the examples was good, and in particular, no phenomena such as pattern disappearance during exposure (decrease in pattern fidelity to the mask) were observed.

Table 6 hydroxyl groups are esterified) (2) naphthoquinone-(1,2)-diazide-(2)-5-sulfonic acid chloride and 2, 3. 4. Condensation product of 4'-tetrahydroxybenzophenone (2.5 hydroxyl groups on average are esterified) (3) Temperature inside the clean open when the resist pattern begins to sag (4) Resolving lines and spaces Minimum line width (5) After exposure, fidelity of the pattern against the mask using an optical microscope ○...Good Δ...Possible ×...Possible (below, margins)

Claims (9)

[Claims] (1) A resin made by condensing m-cresol and 2-tert-butyl-6-methylphenol with aldehydes (
) and a 1,2-quinonediazide compound. (2) In resin (I), m-cresol and 2-t
The molar ratio of ert-butyl-6-methylphenol is 95
2. The positive resist composition according to claim 1, wherein the composition ratio is from :5 to 60:40. (3) In the resin (I), its GPC (detector UV
-254 nm) The area ratio of the polystyrene equivalent molecular weight of 6000 or less to the total area of the pattern is 65
% or less, and the area ratio in the range of 900 or less is 30% or less, and the positive resist composition according to Item 1 or 2, wherein the alkali-soluble resin and the resin (I) have the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R_1, R_2, R_3 represent C_1 to C_5 alkyl groups or C_1 to C_5 alkoxy groups,
l and mn are numbers from 0 to 3, and R' represents a hydrogen atom or an alkyl group of C_1 to C_3. ) (4) R_1 and R_2 are methyl groups, m and n are 2, l
is 0, and R' is a hydrogen atom.
positive resist composition. (5) The positive resist composition according to claim 3 or 4, wherein the content of the compound represented by general formula (II) is 4 to 50 parts by weight based on 100 parts of the total amount of the alkali-soluble resin. (6) In the resin (I), its GPC (detector UV
-254 nm) The area ratio of the polystyrene equivalent molecular weight of 6000 or less to the total area of the pattern is 65
% or less, and the area ratio in the range of 900 or less is 30% or less, and the alkali-soluble resin has a polystyrene equivalent weight average molecular weight of 2000 to 200 by GPC with the resin (I). Novolac (
The positive resist composition according to claim 1 or 2, characterized in that it contains III). (7) The positive resist composition according to claim 6, wherein the content of the low molecular weight novolak (III) is 4 to 50 parts by weight based on 100 parts of the total amount of the alkali-soluble resin. (8) The positive resist composition according to claim 6 or 7, wherein the low molecular weight novolac (III) has a polystyrene equivalent weight average molecular weight of 1000 to 200 by GPC. (9) The positive resist composition according to claim 6, 7 or 8, wherein the low molecular weight novolac (III) is a condensate of cresol and formalin.