JP2003315994A - Positive photoresist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive photoresist composition having excellent sensitivity, resolution, DOF (degree of freedom), exposure latitude, and coarseness/ denseness difference in photolithography using i-line. <P>SOLUTION: The positive photoresist composition comprises (A) an alkali- soluble novokal resin obtained by condensing phenols including m-cresol and 3,4-xylenol and aldehydes and (B) a compound of formula (I) wherein D is H or 1,2-naphthoquinonediazide-5-sulfonyl. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in resist characteristics such as sensitivity, resolution, depth of focus (DOF) characteristics, exposure allowance, and density difference, and particularly an ultrafine resist pattern of 0.35 μm or less. The present invention relates to a positive photoresist composition suitable for the field of forming a film.

[0002]

2. Description of the Related Art In photolithography using i-line (365 nm), half micron or less, especially 0.35 μ
Various positive photoresist compositions containing an alkali-soluble novolac resin and a non-benzophenone-based naphthoquinonediazide group-containing compound (photosensitive component) are available as photoresist materials capable of forming a resist pattern having an ultrafine dimension of m or less. Proposed. In particular, a so-called linear type 4-having a structure in which benzene rings are linearly bonded
Esterification products (quinonediazide esterification products) of low molecular weight phenolic compounds having a 7-nucleoside phenol skeleton and 1,2-naphthoquinonediazide sulfonic acid compounds have been variously reported as photosensitive components exhibiting high resolution. Japanese Patent Laid-Open No. 6-167805, Japanese Patent Laid-Open No. 7-152152
Japanese Patent Laid-Open No. 7-159990, Japanese Patent Laid-Open No. 7-1
No. 68355, No. 8-129255, No. 8-245461, and No. 8-339079.
Japanese Patent Application Laid-Open No. 9-114093, Japanese Patent Application Laid-Open No. 12-
29208 and JP-A-12-29209).

However, in the field of forming an ultrafine resist pattern of 0.35 μm or less, which is shorter than the wavelength of i-line (365 nm), sensitivity, resolution, depth of focus (DOF) characteristic, and exposure margin are further increased. It is desired to form a resist pattern having excellent resist characteristics such as degree. Further, in the field of manufacturing a logic IC (integrated circuit) in which a dense pattern portion which is a regular resist pattern such as a line and space (L & S) pattern and an isolated pattern portion which is an irregular resist pattern are mixed. It has been desired to form a resist pattern having a small so-called "roughness difference", which enables a dense pattern and an isolated pattern to be formed in a desired shape under the same exposure conditions with good shape.
In forming a resist pattern of 0.35 μm or less, KrF (248 nm) or ArF (189 nm)
Although photolithography using short-wavelength exposure sources such as those has been proposed, a large amount of capital investment is required to construct a manufacturing line that uses these exposure sources, and it is not possible to recover the expenses spent on them. Due to problems such as difficulty, it is earnestly desired to extend the life of the i-line (365 nm) exposure process, which is currently the mainstream.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to enable formation of an ultrafine resist pattern of half micron or less, particularly 0.35 μm or less in photolithography using i-line (365 nm). , Sensitivity, resolution, depth of focus (DOF) characteristics, exposure latitude,
It is an object of the present invention to provide a positive photoresist composition having excellent resist characteristics such as difference in density.

[0005]

As a result of intensive studies to solve the above problems, a positive photoresist composition containing a specific alkali-soluble novolac resin and a specific quinonediazide ester compound (photosensitive component) is Also in the field of forming an ultrafine resist pattern of 0.35 μm or less, which is shorter than the wavelength of i-line (365 nm),
The inventors have found that it is possible to form a resist pattern excellent in various resist characteristics such as sensitivity, resolution, depth of focus (DOF) characteristics, exposure allowance, and density difference, and have completed the present invention.

That is, the present invention provides (A) an alkali-soluble novolac resin obtained by subjecting an aldehyde to a condensation reaction of phenols containing m-cresol and 3,4-xylenol, and (B) the following general formula (I) )

[0007]

[Chemical 2]

(In the formula, D independently represents a hydrogen atom or a 1,2-naphthoquinonediazide-5-sulfonyl group, and at least one is 1,2-naphthoquinonediazide-
And a quinone diazide esterified product represented by (5-sulfonyl group). The present invention also provides the positive photoresist composition as described above, wherein the phenols consist only of m-cresol and 3,4-xylenol. Further, the present invention is
The positive photoresist composition is characterized in that the aldehydes are composed of propionaldehyde and formaldehyde only. The present invention also provides the above positive photoresist composition, which further comprises (C) an alkali-soluble low molecular weight compound having a phenolic hydroxyl group having a molecular weight of 1,000 or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described below. (A) component The alkali-soluble novolac resin as the (A) component is
In the novolac resin obtained by the condensation reaction of phenols and aldehydes, as the phenols,
Since it contains m-cresol and 3,4-xylenol, the present invention can provide a positive photoresist composition excellent in compatibility between sensitivity and resolution. In addition, as the aldehydes, those containing propionaldehyde and formaldehyde are preferable, and therefore, in the present invention, further improvement in resolution is desired.

As the above-mentioned phenols, phenols other than m-cresol and 3,4-xylenol can be used, but preferably 50-m-cresol and 3,4-xylenol are used among the phenols used.
It is most preferable that it is composed only of mol% or more, and more preferably only m-cresol and 3,4-xylenol, from the viewpoint that the effect of the present invention can be sufficiently obtained. Similarly, as the aldehyde, propionaldehyde, aldehydes other than formaldehyde, and ketones can be used, but preferably, propionaldehyde and formaldehyde are 80 mol% or more in the aldehydes used, It is most preferable that it consists of propionaldehyde and formaldehyde alone in order to sufficiently obtain the effects of the present invention.

The preferred method for synthesizing the component (A) is to compound (I) an acid catalyst in an amount of 0.1 to 0.5 mole times as much propionaldehyde as 1 mole of m-cresol. A primary reaction is performed to synthesize a polymer, and (II) the polymer is added in an amount of 0.1 to 1 mol of m-cresol.
This is a method of synthesizing a novolak resin by blending 0.5 mol amount of 3,4-xylenol and 1 mol amount of formaldehyde with respect to 1 mol of propionaldehyde and performing a secondary reaction.

In the step (I), 3,4-xylenol is used instead of m-cresol, and in the step (II), novolak synthesized by using m-cresol instead of 3,4-xylenol. Although the resin has high sensitivity, the film loss after development tends to be large. Further, the novolak resin synthesized by simultaneously reacting mixed phenols containing m-cresol and 3,4-xylenol with mixed aldehydes containing formaldehyde and propionaldehyde is slightly inferior in sensitivity and resolution. Tend.

The amount of propionaldehyde compounded in step (I) is 1 mol of m-cresol.
It is preferably 0.1 to 0.5 mol, and particularly preferably 0.2 to 0.4 mol. When it is less than this range, resolution tends to be lowered, and when it is more than this range, sensitivity is lowered and the pattern is reduced. It is not preferable because it tends to cause deterioration of shape (poor verticality).

As the acid catalyst used in the step (I), those commonly used in the synthesis of novolak resins can be used, but p-toluenesulfonic acid and the like are particularly preferable in that the reaction rate is high. The amount of the acid catalyst blended is
It is preferably in the range of 0.1 mmol% to 100 mmol%, particularly 1 mmol% to 10 mmol%, based on the total number of moles of all phenolic monomers used for the synthesis of the component (A). In addition, the reaction is preferably performed in an organic solvent such as γ-butyrolactone.

The polymer thus synthesized has a dispersity (Mw / Mn) of 1.7 or less and an Mw of 200 to.
It is preferably 500, particularly about 200 to 300, from the viewpoint of being suitable for preparation of a high-sensitivity, high-resolution positive photoresist composition. The average molecular weight (Mw, Mn) in the present invention means a polystyrene-equivalent molecular weight measured by GPC (gel permeation chromatography).

3,4-to be blended in the step (II)
The amount of xylenol is preferably 0.1 to 0.5 mol, particularly preferably 0.1 to 0.3 mol, when the compounding amount of m-cresol used in the step (I) is 1 mol. If it is lower than this range, it is difficult to obtain a high-resolution positive photoresist composition, and if it is higher than this range, it is unfavorable since sensitivity tends to deteriorate and verticality of the pattern shape tends to deteriorate.

The amount of formaldehyde blended in the step (II) is 1 to 6 moles, especially 2 to 4 moles, when the amount of propionaldehyde used in the step (I) is 1 mole. If it is lower than this range, it is difficult to obtain a high-resolution positive photoresist composition, and if it is higher than this range, it is difficult to obtain a high-sensitivity positive photoresist composition.

In the reaction (first reaction) of m-cresol and propionaldehyde in the step (I), the reaction time is preferably 2 hours or more. If the time is less than 2 hours, the molecular weight distribution of the core (polymer) produced from m-cresol + propionaldehyde is wide, so the dispersity is large, and the characteristics of the novolak resin synthesized in the subsequent (II) step are inferior. It is difficult to obtain satisfactory effects in terms of total performance such as sensitivity, resolution, DOF characteristics, exposure allowance and difference in density of the positive photoresist composition using The reaction time in the primary reaction is preferably about 4 hours to 8 hours for the sake of industrial productivity.

In the step (II), the solution containing the core (polymer) synthesized in the step (I) as the main component is added to 3,4
-The reaction (secondary reaction) is started by adding xylenol and then formalin (aqueous solution of formaldehyde) at high temperature. The reaction time in the secondary reaction is 2
It is desirable that the time is from 4 hours to 4 hours, and the novolak resin which has reached the target molecular weight by this has sensitivity, resolution,
It is suitable for preparing a positive photoresist composition having excellent DOF characteristics, exposure latitude, and difference in density. The secondary reaction may be carried out for a reaction time of more than 4 hours, but it is not preferable that it is too long for the sake of productivity.

The second reaction may be started by adding 3,4-xylenol and dropping formalin immediately after the completion of the first reaction, but after the completion of the first reaction, the reaction temperature is lowered to about room temperature. , After stopping stirring, 3,4-
Xylenol may be added and then formalin may be added dropwise to start. For example, after the completion of the primary reaction, while the solution is still in a high temperature state, 3,4-xylenol is added, then the temperature is lowered, and the stirring is once stopped. Then, the temperature can be raised again and formalin can be added dropwise to carry out polymerization (secondary reaction). In addition, for example, the temperature of the solution after the primary reaction is lowered, 3,4-xylenol is added, and then the temperature is raised again, and formalin is added dropwise to conduct polymerization (2
The following reaction) can also be performed. At the start of the secondary reaction, it is preferable to add formalin dropwise to the reaction system having a sufficiently elevated temperature in order to prevent the formalin from condensing alone.

The reaction temperature for both the primary reaction and the secondary reaction is 9
It is preferable to carry out at about 0 to 100 ° C., but since the boiling point of propionaldehyde is around 47 ° C., at the time of the primary reaction, first, after carrying out the reaction at the reaction temperature of 40 to 50 ° C. for 0.5 to 1 hour, It is preferable to raise the temperature to 90 to 100 ° C. to carry out the reaction in terms of production safety. In addition, from the beginning 90-1
Even if the reaction is performed at 00 ° C, there is no significant difference in the properties of the synthesized resin. The reaction solution concentration is preferably adjusted by using an organic solvent such as γ-butyrolactone so that the monomer mass of all phenols is 10 to 60% (mass% concentration) in both the primary reaction and the secondary reaction. . 10 mass%
If it is less than 60% by weight, the reaction time until reaching the target molecular weight becomes long, and the purification process such as removal of the reaction solvent becomes difficult, which is not preferable, and if it exceeds 60% by weight, the piping becomes clogged due to sampling or transfer and the work becomes difficult. Therefore, it is not preferable. The component (A) can be synthesized by the “bulk polymerization method” without using an organic solvent such as γ-butyrolactone, but the reaction is carried out uniformly and the amount of by-products is small in the above-mentioned organic solvent. It is preferable to use the above-mentioned polymerization method.

The component (A) thus synthesized is M
w is in the range of 1000 to 20000, particularly 2000 to
The range of 15,000 is preferable from the viewpoint of being suitable for preparation of the positive photoresist composition excellent in the above various resist characteristics.

If desired, the synthesized component (A) is subjected to known operations such as purification and fractionation to remove unreacted substances and low-molecular-weight substances, thereby producing a high-molecular-weight, narrow-dispersion novolak. It is preferably a resin. The method for removing unreacted substances and low molecular weight substances is not particularly limited, but the following method is preferable, for example. First, the novolac resin solution is dissolved in methyl amyl ketone (MAK) and washed with water to remove the catalyst and unreacted materials. Then
To this, a poor solvent such as hexane or heptane, or a hexane-MAK mixed solvent or a heptane-MAK mixed solvent is added and stirred, and then allowed to stand. , The high molecular weight substance is separated into the lower layer. Therefore, by extracting the lower layer, a high molecular weight novolak resin can be obtained.

As the alkali-soluble resin, other alkali-soluble resins may be used in combination with the above-mentioned component (A) within a range not impairing the object of the present invention. For example, a condensation reaction product of an aromatic hydroxy compound and an aldehyde or a ketone, polyhydroxystyrene and a derivative thereof, and the like can be mentioned. However, the amount of these other alkali-soluble resins used is preferably 80% by mass or less, particularly 50% by mass or less, based on the total amount of the alkali-soluble resins, from the viewpoint of not impairing the effects of the present invention.

Examples of the aromatic hydroxy compounds include cresols such as phenol, p-cresol and o-cresol; 2,3-xylenol, 2,5-xylenol, 3,5-xylenol, 2,3,5- Xylenol such as xylenol; m-ethylphenol, p-
Ethylphenol, o-ethylphenol, 2,3,5
-Trimethylphenol, 2,3,5-triethylphenol, 4-tert-butylphenol, 3-ter
t-butylphenol, 2-tert-butylphenol, 2-tert-butyl-4-methylphenol, 2
Alkylphenols such as -tert-butyl-5-methylphenol; alkoxyphenols such as p-methoxyphenol, m-methoxyphenol, p-ethoxyphenol, m-ethoxyphenol, p-propoxyphenol, m-propoxyphenol; o -Isopropenylphenol, p-isopropenylphenol,
Isopropenylphenols such as 2-methyl-4-isopropenylphenol and 2-ethyl-4-isopropenylphenol; arylphenols such as phenylphenol; 4,4'-dihydroxybiphenyl, bisphenol A, resorcinol, hydroquinone, pyrogallol Examples of the polyaldehydes such as polyhydroxyphenols, and the aldehydes include, for example, paraformaldehyde, trioxane, acetaldehyde, butyraldehyde, trimethylacetaldehyde, acrolein, crotonaldehyde, cyclohexanaldehyde, furfural, furylacrolein, benzaldehyde, terephthalaldehyde, Phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxy Benzaldehyde, m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, cinnamic aldehyde and the like. Examples of the above-mentioned ketones include acetone, methyl ethyl ketone, diethyl ketone, diphenyl ketone, and the like, and these can be used alone or in combination of two or more kinds. The condensation reaction product of the aromatic hydroxy compound and the aldehyde or ketone can be produced by a known method in the presence of an acidic catalyst. Examples of the polyhydroxystyrene and its derivatives include homopolymers of vinylphenol, copolymers of vinylphenol and a comonomer copolymerizable therewith, and examples of the comonomers include acrylic acid derivatives and acrylonitrile. , Methacrylic acid derivatives, methacrylonitrile, styrene, α-methylstyrene, p-methylstyrene, o-methylstyrene, p
Examples thereof include styrene derivatives such as -methoxystyrene and p-chlorostyrene.

Component (B) The present invention is also applicable to the field of forming an ultrafine resist pattern of 0.35 μm or less by using the quinonediazide ester compound represented by the general formula (I).
It is possible to form a resist pattern having excellent resist characteristics as described above. The average esterification rate of the esterified product is 40 to 90%, preferably 45 to 75%,
If it is less than 40%, the residual film ratio and resolution are lowered, and if it exceeds 90%, the sensitivity is remarkably lowered, and the development residue (scum) is also decreased.
Is increased, which is not preferable.

As the quinonediazide ester compound, other quinonediazide ester compounds can be used in addition to the component (B). However, the amount of these other quinonediazide ester compounds used is not more than 80% by mass, particularly 50% by mass, based on the total quinonediazide ester compounds.
It is preferably not more than mass% from the viewpoint of not impairing the effects of the present invention.

Other quinonediazide ester compounds include those having a benzophenone skeleton and the following general formula (II)

[0029]

[Chemical 3]

[Wherein, R ^{1 to} R ⁸ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms,
Alkoxy group having 1 to 6 carbon atoms, or 3 carbon atoms
R ^{9 to} R ¹¹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Q is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R ⁹ A cycloalkyl group having 3 to 6 carbon atoms or a residue represented by the following chemical formula (III)

[0031]

[Chemical 4]

(In the formula, R ¹² and R ¹³ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 3 to 6 carbon atoms. Represents a cycloalkyl group; c represents an integer of 1 to 3); D represents a hydrogen atom,
1,2-naphthoquinonediazide-5-sulfonyl group, at least one of which is 1,2-naphthoquinonediazide-
Represents a 5-sulfonyl group; a and b represent an integer of 1 to 3; d represents an integer of 0 to 3; n represents an integer of 0 to 3. ] A quinonediazide ester compound represented by the formula (however, the compound represented by the general formula (I) is excluded), and specifically, 2,4-bis (3,5-dimethyl-4-)
Hydroxybenzyl) -5-hydroxyphenol,
Linear trinuclear compounds such as 2,6-bis (2,5-dimethyl-4-hydroxybenzyl) -4-methylphenol; bis [2,5-dimethyl-3- (4-hydroxy-)
5-methylbenzyl) -4-hydroxyphenyl] methane, bis [2,5-dimethyl-3- (4-hydroxybenzyl) -4-hydroxyphenyl] methane, bis [3
-(3,5-Dimethyl-4-hydroxybenzyl) -4
-Hydroxy-5-methylphenyl] methane, bis [3
-(3,5-Dimethyl-4-hydroxybenzyl) -4
-Hydroxy-5-ethylphenyl] methane, bis [3
-(3,5-diethyl-4-hydroxybenzyl) -4
-Hydroxy-5-methylphenyl] methane, bis [3
-(3,5-diethyl-4-hydroxybenzyl) -4
-Hydroxy-5-ethylphenyl] methane, bis [2
-Hydroxy-3- (3,5-dimethyl-4-hydroxybenzyl) -5-methylphenyl] methane, bis [2
-Hydroxy-3- (2-hydroxy-5-methylbenzyl) -5-methylphenyl] methane, bis [4-hydroxy-3- (2-hydroxy-5-methylbenzyl)
Linear 4-nuclear compound such as -5-methylphenyl] methane; 2,4-bis [2-hydroxy-3- (4-hydroxybenzyl) -5-methylbenzyl] -6-cyclohexylphenol, 2,4- Bis [4-hydroxy-3
-(4-Hydroxybenzyl) -5-methylbenzyl]
Linear polyphenol compounds such as linear pentanuclear compounds such as -6-cyclohexylphenol, tris (4-
Hydroxyphenyl) methane, bis (4-hydroxy-)
3,5-Dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2- Hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3
-Hydroxyphenylmethane, bis (4-hydroxy-
2,5-Dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl)- Three
4-dihydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2,4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2,4-dihydroxyphenylmethane, Bis (4-hydroxyphenyl) -3-methoxy-
4-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -3-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-4-) Hydroxyphenyl) -4
-Hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-4)
-Hydroxy-6-methylphenyl) -3-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (2-methyl-4-hydroxy-5-cyclohexyl) Phenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxyphenyl) -3-hydroxyphenylmethane, bis (3
-Cyclohexyl-6-hydroxyphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-
6-hydroxyphenyl) -2-hydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxy-4)
-Methylphenyl) -2-hydroxyphenylmethane,
Bis (3-cyclohexyl-6-hydroxy-4-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-6-hydroxy-4-methylphenyl) -3,4-dihydroxyphenylmethane, bis (4- Hydroxy-2,3,5-trimethylphenyl)
2-hydroxyphenylmethane, bis (4-hydroxy-2,3,5-trimethylphenyl) -3-hydroxyphenylmethane, bis (4-hydroxy-2,3,5)
-Trimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,3,5-trimethylphenyl) -3,4-dihydroxyphenylmethane, bis (4-hydroxy-2,3,5-trimethylphenyl)
Examples thereof include quinonediazide ester compounds such as trisphenolic polyphenol compounds such as -4-hydroxy-3-methoxyphenylmethane.

In the composition of the present invention, the amount of the quinonediazide ester compounded is 10 to 60% by mass with respect to the total amount of the mass of the alkali-soluble resin and the mass of the following component (C) added as desired. , Preferably 25 to 45% by mass. If the blending amount of the quinonediazide ester compound is less than the above range, an image faithful to the pattern cannot be obtained, and the transferability also deteriorates. On the other hand, if the amount of the quinonediazide ester compound exceeds the above range, the sensitivity is deteriorated and the homogeneity of the formed resist film is deteriorated, and the resolution is deteriorated.

Component (C) (Sensitivity Improver) In the composition of the present invention, the component (C) has a molecular weight of 100.
It is preferable to add an alkali-soluble low-molecular compound (sensitivity improver) having a phenolic hydroxyl group of 0 or less, since the sensitivity improving effect can be obtained. The component (C) is not particularly limited, and examples thereof include a phenol compound that has been conventionally used for the purpose of improving sensitivity in an i-ray positive photoresist composition. For example, polyphenol compounds exemplified in JP-A-3-191351 and polyphenol compounds represented by the general formula (II) (wherein D is replaced with H)
Can be used, and more specifically, 4- (3-hydroxyspiro [5,6,7,8,10a, 8a-hexahydroxanthene-9,1′-cyclohexane] -1
0a-yl) benzene-1,3-diol, 1- [1,
1-bis (4-methylphenyl) ethyl] -4- [1-
(4-hydroxyphenyl) isopropyl] benzene,
Bis (4-hydroxy-2,3,5-trimethylphenyl) -2-hydroxyphenylmethane, 1,4-bis [1- (3,5-dimethyl-4-hydroxyphenyl)
Isopropyl] benzene, 2,4-bis (3,5-dimethyl-4-hydroxyphenylmethyl) -6-methylphenol, bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis ( 4-
Hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-
Dimethylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (3-methyl-4-hydroxyphenyl) isopropyl] -4- [1,1-bis (3-methyl-4-hydroxyphenyl) ethyl] Benzene, 2,6
-Bis [1- (2,4-dihydroxyphenyl) isopropyl] -4-methylphenol, 4,6-bis [1-
(4-Hydroxyphenyl) isopropyl] resorcin, 4,6-bis (3,5-dimethoxy-4-hydroxyphenylmethyl) pyrogallol, 4,6-bis (3,4
5-dimethyl-4-hydroxyphenylmethyl) pyrogallol, 2,6-bis (3-methyl-4,6-dihydroxyphenylmethyl) -4-methylphenol, 2,6
-Bis (2,3,4-trihydroxyphenylmethyl)
-4-Methylphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane and the like are preferred. Among them, 4- (3-hydroxyspiro [5,
6,7,8,10a, 8a-hexahydroxanthene-
9,1′-Cyclohexane] -10a-yl) benzene-1,3-diol, 1- [1,1-bis (4-methylphenyl) ethyl] -4- [1- (4-hydroxyphenyl) isopropyl] Benzene, bis (4-hydroxy-
2,3,5-trimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3,4-dihydroxyphenylmethane,
2,4-bis (3,5-dimethyl-4-hydroxyphenylmethyl) -6-methylphenol and 4,6-bis [1- (4-hydroxyphenyl) isopropyl] resorcin are particularly preferred.

When the component (C) is added to the composition of the present invention, its content is 10 to 6 relative to the alkali-soluble resin.
It is selected in the range of 0% by mass, preferably 20 to 50% by mass.

The composition of the present invention may further contain compatible additives, ultraviolet absorbers for preventing halation such as 2,2 ', 4,4'-tetrahydroxybenzophenone, and 4 if necessary. -Dimethylamino-2 ', 4'
-Dihydroxybenzophenone, 5-amino-3-methyl-1-phenyl-4- (4-hydroxyphenylazo) pyrazole, 4-dimethylamino-4'-hydroxyazobenzene, 4-diethylamino-4'-ethoxyazobenzene, 4- Diethylaminoazobenzene, curcumin, etc., and a surfactant for preventing striation, for example, Florard FC-430, FC431 (trade name, manufactured by Sumitomo 3M Ltd.), F-top EF122A,
A fluorinated surfactant such as EF122B, EF122C, EF126 (trade name, manufactured by Tochem Products Co., Ltd.) and the like can be added and contained within a range that does not hinder the purpose of the present invention.

Further, the composition of the present invention is preferably used in the form of a solution by dissolving the components (A) to (C) and various additives in a suitable solvent. Examples of such a solvent include solvents used in conventional positive photoresist compositions, such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2
-Ketones such as heptanone; ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, or their monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether, etc. Polyhydric alcohols and their derivatives; cyclic ethers such as dioxane; and ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc. Esters can be mentioned. These may be used alone or in combination of two or more. Particularly, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc. Esters are preferred.

An example of a preferred method of using the composition of the present invention will be described. First, the component (A), the component (B), and the component (C) and various components which are optionally added are described above. It is dissolved in a suitable solvent such as the above, coated on a silicone wafer or a support having an antireflection film formed thereon with a spinner, etc., and dried to form a photosensitive layer. Line exposure. Next, this is immersed in a developing solution, for example, an alkaline aqueous solution such as a 1 to 10 wt% tetramethylammonium hydroxide (TMAH) aqueous solution, whereby the exposed portion is dissolved and removed, and an image faithful to the mask pattern can be obtained.

[0039]

EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples. [Synthesis Example 1] (m-cresol / 3,4-xylenol = molar ratio 8 /
Synthesis of resin No. 2) (Primary reaction) Mechanical stirrer, cooler, 300 m
l dripping funnel, 1 liter 4 equipped with nitrogen gas inlet tube
A 2-necked flask was charged with m-cresol 86.4 g (0.8 mol), p-toluenesulfonic acid 2.0 g, and γ-butyrolactone 86.4 g, and the reaction solution concentration was 50.
It was adjusted so as to be mass%. Then, while flowing nitrogen gas, the flask was heated in an oil bath stirred by a magnetic stirrer so that the internal temperature of the reaction solution became 1
When the temperature reached 00 ° C., 12.22 g (0.2 mol) of 95% by mass aqueous propionaldehyde solution was slowly added dropwise from the dropping funnel over 30 minutes, and after the addition, the reaction was carried out for 4 hours. The obtained reaction product was sampled and found to have a polystyrene equivalent weight average molecular weight (Mw) of 25.
0, Mw / Mn (number average molecular weight) was 1.65. (Secondary reaction) Next, 24.4 g of 3,4-xylenol
A solution prepared by dissolving (0.2 mol) in 24.4 g of γ-butyrolactone was charged into the reaction solution after the above primary reaction, and then 40.9 g of 37% by mass aqueous formaldehyde solution.
(0.5 mol) slowly added dropwise over 30 minutes,
After the dropping, the reaction was performed for 10 hours. After completion of the reaction, the reaction vessel was cooled to room temperature sufficiently, and then the reaction solution was adjusted to a 20 mass% concentration solution using MAK (methyl amyl ketone), washed 3 times with a 3 liter separating funnel, and then evaporated. Concentrated in. Then, it is diluted with MAK and methanol to obtain MAK / methanol having a concentration of 15% by mass = 4 /
The solution was adjusted to 1 (mass ratio). The solution was put in a 3 liter separating funnel, and n-heptane was added thereto to remove a low molecular weight monomer-containing monomer, thereby obtaining an alkali-soluble novolak resin (Mw = 5000) as the target component (A).

[Synthesis Examples 2 to 5] and [Comparative Synthesis Examples 1 to 4] The types and blending amounts of the phenols and the aldehydes and their blending amounts used in Synthesis Example 1 are shown in Table 1 below.
Each of the alkali-soluble novolac resins was synthesized in the same manner as in Synthesis Example 1 except that the one described in 1 was used.

[0041]

[Table 1]

[Example 1] Alkali-soluble resin: [Alkali-soluble novolak resin synthesized in Synthesis Example 1] 100 parts by mass Quinone diazide ester compound: (b1) / (b2) = 10/1 (mass ratio) 40 parts by mass [ (B1): 1 mol of 1,1-bis [3- (2-hydroxy-5-methylbenzyl) -4-hydroxy-5-cyclohexylphenyl] isopropane and 2 mol of 5-NQD (1,2-naphtho) Esterification product with quinonediazide-5-sulfonic acid chloride) (esterification rate 50%), (b2): Esterification product with 1 mol of methyl gallate and 3 mols of 5-NQD (esterification ratio 100%)] ( Component C: 30 parts by mass of sensitivity improver [4- (3-hydroxyspiro [5,6,7,8,10]
a, 8a-Hexahydroxanthene-9,1'-cyclohexane] -10a-yl) benzene-1,3-diol]

2-heptanone (MAK)
After dissolving in 480 parts by mass, this was filtered using a membrane filter having a pore size of 0.2 μm to prepare a positive photoresist composition. The following evaluation items (1) to (5) were evaluated for the positive photoresist composition, and the results are shown in Table 3.

[Examples 2 to 8], [Comparative Examples 1 to 8] Each positive photoresist was prepared in the same manner as in Example 1 except that the alkali-soluble resin and the quinonediazide ester compound were replaced with those shown in Table 2 below. A composition was prepared.
The following evaluation items (1) to (5) were evaluated for the positive photoresist composition, and the results are shown in Table 3. The symbol "-" in Table 3 means that a resist pattern of 0.35 μm (line and space width 1: 1) could not be formed.

Various physical properties of the positive photoresist composition were determined as follows. (1) Sensitivity: A sample was coated on a silicon wafer using a spinner, and this was coated on a hot plate at 90 ° C. for 90
After drying for 2 seconds, a resist film having a film thickness of 1.05 μm was obtained. 0.35 μm with 1: 1 line and space width
Using a reduction projection exposure apparatus NSR-2005i10D (manufactured by Nikon Corporation, NA = 0.57) through a mask (reticle) corresponding to a resist pattern, 0.1 seconds to 0.01
After exposing every second, PEB at 110 ℃ for 90 seconds
(Post-exposure heating) treatment is performed, and then treated with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution.
It was developed at 60 ° C. for 60 seconds, washed with water for 30 seconds and dried. At that time, the optimum exposure time (Eop) at which the line and space width of the 0.35 μm resist pattern is formed to 1: 1
Is expressed as a sensitivity in milliseconds (ms). (2) Resolution: The limit resolution at the exposure dose for reproducing a 0.35 μm mask pattern was shown. (3) DOF characteristics: reduction projection exposure apparatus NSR-2005
Using i10D (manufactured by Nikon Corporation, NA = 0.57), E
op (line and space width of 0.35 μm is 1: 1
The exposure amount required to form the film was used as the reference exposure amount, and the SEM photograph of the resist pattern obtained by performing the exposure and development by appropriately shifting the focus up and down in the exposure amount was observed. The maximum value of defocus (μm) that can obtain a 0.35 μm rectangular resist pattern from the SEM photograph
Is the DOF (depth of focus width) characteristic. (4) Underexposure margin: The sample was applied onto a silicon wafer using a spinner and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film with a thickness of 1.05 μm. Line and space width of this film is 1: 1
Reduction projection exposure apparatus NSR-2005i10 through a mask (reticle) corresponding to the 0.35 μm resist pattern
D (manufactured by Nikon Corporation, NA = 0.57) was used for exposure at intervals of 0.1 seconds to 0.01 seconds, and then PEB (post-exposure heating) treatment was performed at 110 ° C. for 90 seconds to 2.38. mass%
It was developed with an aqueous TMAH solution at 23 ° C. for 60 seconds, washed with water for 30 seconds and dried. At that time, the minimum exposure amount (Es) capable of forming a separation pattern after development is set to milliseconds (m).
The underexposure margin is expressed as Eop-Es. (5) Evaluation of difference in density: Eop (exposure amount required to form a line-and-space width of 0.35 μm at 1: 1)
Is used as a reference exposure amount, the dimension (X) of the actually obtained isolated pattern is measured when the isolated resist pattern is formed using a mask corresponding to the isolated (Iso) pattern of 0.35 μm, and the ideal Pattern size (0.35μ
The absolute value of the dimensional difference from m) was expressed as "roughness difference". Density difference = | 0.35-X | (where X is the size of the actual isolated pattern)

[0046]

[Table 2]

(B1): 1 mol of 1,1-bis [3-
(2-hydroxy-5-methylbenzyl) -4-hydroxy-5-cyclohexylphenyl] isopropane and 2
Molar 5-NQD (1,2-naphthoquinonediazide-5
-Esterification product with sulfonic acid chloride) (esterification rate 50%) (b2): 1 mol of methyl gallate and 3 mol of 5-NQ
Esterification product with D (esterification rate 100%) (b3): 1 mol of bis (2-methyl-4-hydroxy-5-cyclohexylphenyl) -3,4-dihydroxyphenylmethane and 2 mol of 5-NQD (Esterification rate of 50%) (b4): 1 mol of bis (4-hydroxy-3,5-dimethylphenyl) -2-hydroxyphenylmethane and 2
Esterified product with 5 mol of 5-NQD (esterification ratio 66
%) (B5): 1 mol of bis [2-hydroxy-3- (2-
Hydroxy-5-methylbenzyl) -5-methylphenyl] methane esterified with 2 mol of 5-NQD (esterification rate 50%) (b6): 1 mol of bis [2,5-dimethyl-3- ( Four
-Hydroxy-5-methylbenzyl) -4-hydroxyphenyl] methane with 2 mol of 5-NQD (esterification rate 50%)

[0048]

[Table 3]

[0049]

According to the present invention, in photolithography using i-line (365 nm), it is possible to form a resist pattern having an ultrafine dimension of half micron or less, particularly 0.35 μm or less, and sensitivity and resolution can be formed. Provided is a positive photoresist composition which is excellent in various resist characteristics such as property, depth of focus (DOF) characteristics, exposure latitude, and density difference.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuhiko Nakayama             150 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa East             Within Kyoka Kogyo Co., Ltd. F term (reference) 2H025 AA01 AA02 AB16 AC01 AC04                       AC08 AD03 BE01 CB29 CB52                       CC20 FA03 FA17

Claims (4)

[Claims] 1. An alkali-soluble novolak resin obtained by (A) a condensation reaction of phenols containing m-cresol and 3,4-xylenol with aldehydes, and (B) the following general formula (I): 1] (In the formula, D independently represents a hydrogen atom or a 1,2-naphthoquinonediazide-5-sulfonyl group, and at least one represents a 1,2-naphthoquinonediazide-5-sulfonyl group). A positive photoresist composition containing an esterified product. 2. The positive photoresist composition according to claim 1, wherein the phenols consist only of m-cresol and 3,4-xylenol. 3. The positive photoresist composition according to claim 1, wherein the aldehydes are composed of propionaldehyde and formaldehyde only. 4. The positive photoresist composition according to claim 1, further comprising (C) an alkali-soluble low-molecular compound having a phenolic hydroxyl group having a molecular weight of 1,000 or less.