JPH0736180A - Positive type resist solution - Google Patents

Abstract

PURPOSE:To provide a positive type resist soln. preventing the deposition of the photosensitive component of the resist, undergoing no change of the sensitivity and viscosity with the lapse of time, excellent in shelf stability, having high resolution, a wide defocus margin and practicality and especially suitable for use in the production of a semiconductor device. CONSTITUTION:An alkali-soluble resin (A), a compd. (B) having a quinone- diazido group and phosphorous ester (C) represented by a general formula P(OR)3 (where R is lower alkyl) are dissolved in propylene glycol monoalkyl ether acetate. The amt. of the component C is 0.001-0.1wt.% of the total amt. of the components A, B. The objective positive type resist soln. is obtd.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel positive resist solution, and more specifically, it is used effectively in the field of semiconductor device manufacture, and is free from precipitation of photosensitive components of resist and changes with time in sensitivity and viscosity, and storage. The present invention relates to a practical positive resist solution having excellent stability, high resolution, and wide defocus margin.

[0002]

2. Description of the Related Art In lithography technology used in the manufacturing process of semiconductor devices, as a positive resist having excellent resolution, a resist mainly composed of a mixture of a novolac resin and a quinonediazide group-containing compound is widely used. The contained compound has a poor compatibility with a solvent and has a drawback that it tends to precipitate in a resist composition.

Therefore, the development of positive type resists is generally directed to the enhancement of sensitivity mainly by solving such compatibility problems of the resist composition, especially the generation of foreign matters.

For example, it is known that the sensitivity is increased by increasing the degree of esterification of a quinonediazide group-containing compound which is an esterification reaction product of polyhydroxybenzophenone and naphthoquinone-1,2-diazidesulfonyl chloride. Since the quinonediazide group-containing compound lacks compatibility with a solvent, increasing the degree of esterification further lowers the solubility in the solvent.

Therefore, in order to improve such solubility, various solvents have been studied as a resist solution.

Conventionally, as a solvent for a positive resist, ethylene glycol monoethyl ether acetate has been used among the commonly used solvents. However, its solubility is insufficient. Non was proposed (JP-A-59-155838). However, this one has poor stability as a solvent,
There is a drawback that the sensitivity changes with time easily.

Alkyl monooxymonocarboxylates have also been used (Japanese Patent Application Laid-Open No. 62-123444), which has too high hygroscopicity to cause precipitation of a photosensitive component and also has storage stability. It is not good, and a combination of a cyclic ketone and an alcohol has been proposed (US Pat. No. 4,526,856), but also in this case, a photosensitive component is likely to be deposited and storage stability is poor. In addition, propylene glycol alkyl ether acetate is also known (Japanese Patent Laid-Open No. 61-7837), but this also has a large change in sensitivity and viscosity with time. As a positive resist solution, if the sensitivity and viscosity change significantly over time, it becomes difficult to control the exposure time and film thickness in the lithography process, and especially in the semiconductor device manufacturing field where high accuracy is required, the sensitivity and viscosity change slightly over time. However, it is a big problem because it affects the yield. As described above, none of the conventional solvents is practical.

Moreover, the positive resist solution using these solvents has a narrow exposure margin (defocus margin) in the exposure process and is poor in practicality.

[0009]

Under the circumstances described above, the present invention is free from the precipitation of the photosensitive component of the resist and the change in sensitivity and viscosity over time, and is excellent in solubility, storage stability and high in stability. The purpose of the present invention is to provide a practical positive resist solution having a wide defocus margin in resolution.

[0010]

Means for Solving the Problems The present inventors have conducted various studies on positive resist solutions comprising an alkali-soluble resin, a quinonediazide group-containing compound and an organic solvent, and as a result, have identified specific alkyl phosphite compounds as these components. It was found that a very stable solution can be obtained by blending the above and using propylene glycol monoalkyl ether acetate as the organic solvent, and based on this finding, the present invention has been completed.

That is, the present invention provides (A) an alkali-soluble resin, (B) a quinonediazide group-containing compound and (C).
0.001-based on the total amount of component (A) and component (B)
An amount of the phosphite represented by the general formula P- (OR) ₃ (I) (wherein R represents a lower alkyl group) in an amount in the range of 0.1% by weight is mixed with propylene glycol monoalkyl ether acetate. The present invention provides a positive resist solution prepared by dissolving in.

Examples of the alkali-soluble resin as the component (A) used in the solution of the present invention include novolac resins, acrylic resins, copolymers of styrene and acrylic acid, polymers of hydroxystyrene, polyvinylphenol, poly-α-methylvinyl. Examples thereof include phenol, and among them, alkali-soluble novolac resin is particularly preferable. The alkali-soluble novolak resin is not particularly limited, and those conventionally used as a film-forming substance in a positive resist solution, for example, an aromatic hydroxy compound such as phenol, cresol, or xylenol and an aldehyde such as formaldehyde are acidified. Those condensed in the presence of a catalyst are used. The alkali-soluble novolac resin has a weight average molecular weight of 2,000 to 20,000, preferably 5,000 to 15 with the low molecular weight region cut.
The range of 000 is preferable.

In the solution of the present invention, the photosensitive component (B)
As the compound, a quinonediazide group-containing compound is used. Examples of the quinonediazide group-containing compound include compounds having a sulfonic acid of quinonediazides such as orthobenzoquinonediazide, orthonaphthoquinonediazide, orthoanthraquinonediazide or a functional derivative thereof (for example, sulfonic acid chloride) and a phenolic hydroxyl group or an amino group. Partial or complete esterification of or and partial or complete amidation are mentioned.

Examples of the compound having a phenolic hydroxyl group or an amino group include (1) 2,3,4-trihydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3,4, and Polyhydroxybenzophenones such as 4'-tetrahydroxybenzophenone, (2) 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, (3 ) Tris (4-
Hydroxyphenyl) methane, bis (4-hydroxy-)
3,5-Dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -4-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -2- Tris (hydroxyphenyl) methanes such as hydroxyphenylmethane and bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, or their methyl-substituted products, (4) bis (3-cyclohexyl-4-hydroxy) Phenyl) -3-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl)-
2-hydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxyphenyl) -4-hydroxyphenylmethane, bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -2-hydroxyphenylmethane, bis (5- Cyclohexyl-4-hydroxy-2
-Methylphenyl) -3-hydroxyphenylmethane,
Bis (5-cyclohexyl-4-hydroxy-2-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -3
-Hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl-2-hydroxyphenyl) -2-hydroxyphenylmethane, bis (5
-Cyclohexyl-2-hydroxy-4-methylphenyl) -2-hydroxyphenylmethane, bis (5-cyclohexyl-2-hydroxy-4-methylphenyl)-
Tris (cyclohexylhydroxyphenyl) methanes such as 4-hydroxyphenylmethane or its methyl-substituted compounds, (5) other compounds having a hydroxyl group or an amino group, such as phenol, phenol resin, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, polyhydroxydiphenylalkane, polyhydroxydiphenylalkene, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether, pyrogallol Examples thereof include -1,3-dimethyl ether, gallic acid, esterified or etherified gallic acid with some hydroxyl groups remaining, aniline, and p-aminodiphenylamine.

Particularly preferred quinonediazide group-containing compounds are polyhydroxybenzophenone and naphthoquinone-
1,2-diazide-5-sulfonic acid or naphthoquinone-
It is a complete esterified product or a partial esterified product with 1,2-diazide-4-sulfonic acid, and particularly, one having an average degree of esterification of 70% or more is preferable.

The solution of the present invention may contain, as the photosensitive component, one type of the above-mentioned quinonediazide group-containing compound or two or more types thereof.

This quinonediazide group-containing compound can be obtained by using, for example, the above-mentioned polyhydroxybenzophenone, naphthoquinone-1,2-diazide-5-sulfonyl chloride or naphthoquinone-1,2-diazide-4-sulfonyl chloride in a suitable solvent such as dioxane. It can be produced by condensing in the presence of an alkali such as triethanolamine, an alkali carbonate or an alkali hydrogencarbonate to complete esterification or partial esterification.

In the solution of the present invention, as the component (C), that is, the phosphite ester of the above-mentioned general formula (I), which is blended with the main agent comprising (A) an alkali-soluble resin and (B) a quinonediazide group-containing compound, for example, Examples thereof include trimethyl phosphate, triethyl phosphite, and tripropyl phosphite, with triethyl phosphite being particularly preferred. These may be used alone or in combination of two or more.

The compounding amount of this phosphite is (A)
It is selected in the range of 0.001 to 0.1% by weight, preferably 0.005 to 0.05% by weight, based on the total amount of the alkali-soluble resin and the (B) quinonediazide group-containing compound. If it deviates from this range, a practical positive resist solution with little change in sensitivity and viscosity with time cannot be obtained.

Next, as the solvent in the solution of the present invention,
It is necessary to use propylene glycol monoalkyl ether acetate, and a stable solution cannot be obtained with other solvents. As the propylene glycol monoalkyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate and the like are preferable. These may be used alone or in combination of two or more.

In the solution of the present invention, if desired, other organic solvents can be used in combination so long as the effects of the present invention are not affected. In this case, examples of the organic solvent which can be used in combination include acid ester solvents, particularly fatty acid alkyl esters, or monoalkyl ethers of alkylene glycols, acetic acid esters thereof, other benzyl ethyl ether, dihexyl ether, cyclohexanone, diisobutyl ketone, toluene, xylene, etc. Can be mentioned. Examples of the fatty acid alkyl ester include methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and the like of alkylene glycol. Examples of monoalkyl ethers or acetic acid esters thereof include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether,
Examples thereof include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monomethyl ether acetate. These may be used alone or in combination of two or more.

When the quinonediazide group-containing compound is an ester having a high degree of esterification, or when it is an amidated product other than the ester, a solvent conventionally used as a solvent for a positive resist is used. It is preferable to use in combination with such an extent that it does not affect, but examples of the solvent that can be used in this case include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
Examples thereof include ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, benzyl ethyl ether and dihexyl ether, ketones such as cyclohexanone and diisobutyl ketone, and aromatic hydrocarbons such as toluene and xylene.

In the present invention, when the above-mentioned propylene glycol monoalkyl ether acetate is used in combination with the above organic solvent, the amount thereof is 50% by weight or less, preferably 30% by weight or less, based on propylene glycol monoalkyl ether acetate. Selected in a range.

In the solution of the present invention, the quinonediazide group-containing compound is usually 10 to 40 parts by weight, preferably 18 to 3 parts by weight, based on 100 parts by weight of the alkali-soluble resin.
Used in the range of 0 parts by weight. If the amount of this quinonediazide group-containing compound is too small, it is difficult to obtain a resist pattern having a practical shape, and if it is too large, the sensitivity decreases.

The organic solvent used in the present invention is for dissolving the solid soluble alkali-soluble resin and the quinonediazide group-containing compound, and the amount used is not particularly limited as long as these components can be completely dissolved. However, the range that gives a good coating property and obtains a coating film having a desired film thickness is usually 50 to 200 per 100 parts by weight of the total amount of the alkali-soluble resin and the quinonediazide group-containing compound.
A range of 0 parts by weight, preferably 100 to 1000 parts by weight is suitable. If this amount is less than 50 parts by weight, the viscosity becomes high and it becomes difficult to handle, and if it exceeds 2000 parts by weight, the concentration becomes low and it takes time to adjust the coating amount and dry, and the workability deteriorates.

In the solution of the present invention, if necessary, compatible additives such as an additional resin, a plasticizer, a stabilizer for improving the performance of the resist film, or a pattern obtained by development is added. A colorant for making it more visible, and a conventional component such as a sensitizer for improving the sensitizing effect and a contrast improving agent may be added and contained.

The solution of the present invention is prepared by dissolving the alkali-soluble resin, the quinonediazide group-containing compound, the phosphite ester, and the optional components used as necessary in the organic solvent in the required amounts.

As an example of the use mode of the solution of the present invention, first, on a support such as a silicon wafer, the above-mentioned alkali-soluble resin, quinonediazide group-containing compound and phosphite ester are mixed with propylene glycol monoalkyl ether acetate. A solution obtained by dissolving it in an organic solvent containing as a main component is applied by a spinner or the like to form a photosensitive layer by drying, and then a light source which emits ultraviolet rays, for example, a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, an arc lamp, Exposure is performed through a required mask pattern using a xenon lamp or the like, exposure is performed with a reduction projection exposure apparatus, excimer laser or X-ray irradiation is performed through the mask pattern, or irradiation is performed while scanning an electron beam. Next, when this is dipped in a developing solution, for example, an alkaline aqueous solution such as a 1-10 wt% tetramethylammonium hydroxide aqueous solution, the portion solubilized by exposure is selectively dissolved and removed, and an image faithful to the mask pattern is obtained. Can be obtained.

Such a pattern is not limited to semiconductor processing, but is applied in fields where lithography is used, such as LC.
The same excellent effect can be obtained for D, TAB, PCB, chemical milling, printing and the like.

[0030]

EFFECTS OF THE INVENTION The positive resist solution of the present invention contains the alkyl phosphite ester of the general formula (I), and is not stored with precipitation of the photosensitive component of the resist or change with time in sensitivity and viscosity. Since it is excellent in stability and can widen the defocus margin with high resolution, it can be extremely practically used particularly in the field of semiconductor device manufacturing such as ULSI requiring a fine processing degree of half micron.

[0031]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

The physical properties in each example are obtained by the following methods. (1) Sensitivity A positive resist solution was applied on a silicon wafer by a spinner and dried on a hot plate at 110 ° C. for 90 seconds to form a resist film having a film thickness of 1.3 μm. The reduced projection exposure apparatus NSR- 1505G-4D (manufactured by Nikon Corporation) is used for 0.1 seconds to 0.1% through a predetermined mask.
After exposure at intervals of 2 seconds, development with a 2.38 wt% tetramethylammonium hydroxide aqueous solution for 1 minute was performed.
The minimum exposure time required for forming a pattern by washing with water for 2 seconds and drying was measured as the sensitivity.

(2) Resolution The limit resolution at the exposure dose for reproducing a 1.0 μm mask pattern is shown.

(3) Defocus margin The depth of focus of a 0.5 μm resist pattern at an exposure dose that allows a 0.5 μm mask pattern to be accurately reproduced is shown.

(4) Storage stability (presence or absence of precipitates) The prepared positive resist solution was filtered through a 0.2 μm membrane filter and then allowed to stand at 40 ° C. for 3 months, and then the presence or absence of precipitates in the solution. Was observed. Those with no precipitate were evaluated as no, and those with precipitate were evaluated as being.

(5) Storage Stability (Change in Sensitivity) The prepared positive resist solution was allowed to stand at room temperature for 3 months, the sensitivity was measured, and the change from the sensitivity immediately after preparation was observed. The sensitivity change rate of 25% or less was evaluated as ◯, and the sensitivity change rate of more than 25% was evaluated as x.

(6) Storage stability (change in viscosity) The prepared positive resist solution was allowed to stand at room temperature for 3 months, the viscosity was measured with a Canon Fenske viscometer, and the viscosity of the one immediately after preparation was compared. The change was observed. The case where the amount of change in viscosity was 0.5 cP or less was evaluated as ◯, and the case where it exceeded 0.5 cP was evaluated as x.

Examples 1 to 6 m-cresol and p-cresol in a weight ratio of 60: 4
100 parts by weight of cresol novolac resin obtained by mixing at a ratio of 0, adding formalin to this and conducting a condensation reaction by an ordinary method using an oxalic acid catalyst, 2,3,4,4'-
Based on 25 parts by weight of a reaction product of 1 mol of tetrahydroxybenzophenone and 2.5 mol of naphthoquinone-1,2-diazide-5-sulfonyl chloride, based on the total amount thereof,
0.002% by weight, 0.005% by weight, 0.01% by weight, 0.03% by weight, 0.05% by weight or 0.09% by weight of triethyl phosphite was added, and this was mixed with propylene glycol monomethyl ether. After dissolving in 390 parts by weight of acetate, the mixture was filtered using a 0.2 μm membrane filter to prepare a positive resist solution. The physical properties of this positive resist solution were examined, and the results are shown in Table 1.

Comparative Example A positive resist solution was prepared in the same manner as in Example except that propylene glycol monomethyl ether acetate containing no triethyl phosphite was used.
Table 1 shows the physical properties of this solution.

[0040]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuo Tokutake 150 Nakamaruko, Nakahara-ku, Kawasaki, Kanagawa Tokyo Ohka Kogyo Co., Ltd. (72) Hidekatsu Ohara 150 Nakamaruko, Nakahara-ku, Kawasaki, Kanagawa Tokyo Ohka Kogyo Co., Ltd. (72) Inventor Hisasa Nakayama 150 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Tokyo Ohka Kogyo Co., Ltd.

Claims (2)

[Claims] 1. An (A) alkali-soluble resin, (B) quinonediazide group-containing compound, and (C) (A) component and (B)
An amount of the phosphite represented by the general formula P- (OR) ₃ (wherein R represents a lower alkyl group) in the range of 0.001 to 0.1% by weight based on the total amount of the components. A positive resist solution prepared by dissolving propylene glycol monoalkyl ether acetate. 2. The positive resist solution according to claim 1, wherein the phosphite is triethyl phosphite.