JPH0654381B2 - Positive resist for integrated circuit fabrication - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to ultraviolet rays, deep ultraviolet rays, X-rays, electron beams, molecular beams,
The present invention relates to a positive resist for manufacturing integrated circuits, which is sensitive to radiation such as γ rays, synchrotron radiation, and proton beam.

(Prior Art) Since a positive resist for producing an integrated circuit contains an alkali-insoluble 1,2-quinonediazide compound in an alkali-soluble resin, it hardly dissolves in a developing solution composed of an alkaline aqueous solution and hardly swells. That is, even if the 1,2-quinonediazide compound in the UV-irradiated portion is changed to indenecarboxylic acid and developed in a developer containing an alkaline aqueous solution, the unirradiated portion to be the resist pattern has extremely little change. A faithful and high-resolution resist pattern can be obtained. Therefore, in recent years, when high integration of integrated circuits is required, positive resists having excellent resolution are often used, but there is a limit because the integration of high integration is rapidly increasing. It is desired to improve the resolution of the positive resist in line with the speed at which the degree increases year by year. When the degree of integration is not as high as it is now, that is, in the case of the conventional degree of integration, the interval between the resist patterns to be formed is wide and no problem occurs in resolution. Is less than 1 μm, the developability of the hem portion of the resist pattern is large and the resolution is affected.

Therefore, at the present time when a high degree of integration is required, there is a strong demand for development of a positive resist which has good developability and can resolve a resist pattern having a line width of 1 μm or less.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a positive resist for producing an integrated circuit with high integration.

(Means for Solving Problems) The present invention provides m-cresol and a significant amount of p-cresol,
2,3-xylenol, 2,4-xylenol, 2,5
-At least one phenol selected from xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, resorcinol and 2-methylresorcinol in the presence of an acid catalyst. Alkali-soluble novolac resin synthesized by addition condensation (hereinafter referred to as "specific novolac resin")
For 100 parts by weight, the following (I) (In the formula, R _{1 to} R ₁₀ are the same or different, a hydroxyl group,
The presence of a basic catalyst, a polyhydroxy compound represented by a hydrogen atom or a methyl group and having the number of hydroxyl groups in the formula is 5 ≦ l ≦ 10) and 1,2-quinonediazide sulfonic acid halide 1,2-quinonediazide compound obtained by reacting below (hereinafter referred to as "specific 1,2-quinonediazide compound") 5 to 100
It is intended to provide a positive resist for producing an integrated circuit, which is characterized by being mixed with parts by weight.

In the positive resist of the present invention, the specific 1,2-quinonediazide compound used as a photosensitizer is a polyhydroxy compound represented by the formula (I) and a 1,2-quinonediazidesulfonic acid halide in the presence of a basic catalyst. It is obtained by reacting below.

Examples of the polyhydroxy compound of the above formula (I) include 2,3,4,2 ', 4'-pentahydroxybenzophenone, 2,3,4,2', 5'-pentahydroxybenzophenone and 2,3,4. , 2 ', 6'-pentahydroxybenzophenone, 2,3,4,3', 4'-pentahydroxybenzophenone, 2,3,4,3 ', 5'-pentahydroxybenzophenone, 2,3,4,2 ′,
3 ', 4'-hexahydroxybenzophenone, 2,
3,4,3 ', 4', 5'-hexahydroxybenzophenone, 2,3,4,2 ', 4', 6'-hexahydroxybenzophenone, 2,4,6,2 ', 4'-pentahydroxy Benzophenone, 2,4,6,2 ', 5'-
Pentahydroxybenzophenone, 2,4,6,2 ',
6'-pentahydroxybenzophenone, 2,4,6
3 ', 4'-pentahydroxybenzophenone, 2,
4,6,3 ', 5'-pentahydroxybenzophenone, 2,4,6,3', 4 ', 5'-hexahydroxybenzophenone, 2,4,6,2', 4 ', 6'-hexahydroxy Benzophenone, 2,3,4,5,2'-
Pentahydroxybenzophenone, 2, 3, 4, 5,
3'-pentahydroxybenzophenone, 2,3,4
5,4'-pentahydroxybenzophenone, 2,3
4,5,2 ', 4'-hexahydroxybenzophenone, 2,3,4,5,2', 5'-hexahydroxybenzophenone, 2,3,4,5,2 ', 6'-hexahydroxybenzophenone, 2,3,4,5,3 ', 4'
-Hexahydroxybenzophenone, 2,3,4,5
3 ', 5'-hexahydroxybenzophenone, 2,
3,4,5,2 ', 3', 4'-heptahydroxybenzophenone, 2,3,4,5,3 ', 4', 5'-heptahydroxybenzophenone, 2,3,4,5,2 ' ，
4 ', 6'-heptahydroxybenzophenone, 2,
3,4,2 ', 4'-pentahydroxy-5-methylbenzophenone, 2,3,4,2', 5'-pentahydroxy-5-methylbenzophenone, 2,3,4,2 ',
6'-pentahydroxy-5-methylbenzophenone,
2,3,4,3 ', 4'-pentahydroxy-5-methylbenzophenone, 2,3,4,3', 5'-pentahydroxy-5-methylbenzophenone, 2,3,4
2 ', 3', 4'-hexahydroxy-5-methylbenzophenone, 2,3,4,3 ', 4', 5'-hexahydroxy-5-methylbenzophenone, 2,3,4
2 ', 4', 6'-hexahydroxy-5-methylbenzophenone and the like can be mentioned. These polyhydroxy compounds may be used alone or in combination of two or more.

Examples of the 1,2-quinonediazide sulfonic acid halide include 1,2-naphthoquinonediazide-5-sulfonic acid chloride, 1,2-naphthoquinonediazide-4-sulfonic acid chloride and 1,2-benzoquinonediazide-4.
-Sulfonic acid chloride and the like can be mentioned. These 1, 2
-Quinonediazide sulfonic acid halides alone or
Used in combination of more than one species.

The amount of 1,2-quinonediazide sulfonic acid halide used with respect to the compound of formula (I) is appropriately adjusted depending on the number of hydroxyl groups in the compound of formula (I) and is not particularly limited. 0.1 to 1 mol per 1 equivalent of the hydroxyl group of the compound).

As the basic catalyst, amines such as trimethylamine, triethylamine, tripropylamine, pyridine and tetramethylammonium hydroxy, or inorganic alkalis such as sodium hydroxide, potassium hydroxide and sodium carbonate are used.

The amount of these basic catalysts used is usually 0.8 to 1 per mol of 1,2-quinonediazidesulfonic acid halide.
It is 2.0 mol, preferably 1.0 to 1.5 mol.

In the above-mentioned reaction, usually, as a reaction medium, for example, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, cyclic ethers such as dioxane and tetrahydrofuran, cyclic ketones such as cyclopentanone and cyclohexanone, N, N-dimethylformamide, N, N
-Amides such as dimethylacetamide, γ-butyrolactone, esters such as ethylene carbonate and propylene carbonate,
Pyrrolidone, N-methylpyrrolidone or water is used. The amount of these reaction media used depends on the amount of compound 1 of formula (I).
It is usually 100 to 1000 parts by weight with respect to 00 parts by weight. The reaction temperature of this reaction is usually -30 to 6
It is 0 ° C, preferably 0 to 40 ° C.

In the composition of the present invention, the compounding amount of the specific 1,2-quinonediazide compound is 5 to 100 parts by weight, preferably 10 to 5 parts by weight, relative to 100 parts by weight of the specific novolac resin.
0 parts by weight. When the amount is less than 5 parts by weight, the specific 1,2-quinonediazide compound has a small amount of carboxylic acid generated by absorbing radiation, and thus patterning is difficult. When the amount exceeds 100 parts by weight, Irradiation for a short time cannot decompose all of the added specific 1,2-quinonediazide compound, making it difficult to develop with a developer containing an alkaline aqueous solution.

In the positive resist of the present invention, another 1,2-quinonediazide compound may be added in an amount that does not impair the performance. Examples of these 1,2-quinonediazide compounds include (poly) hydroxybenzene 1,2
-Quinonediazide sulfonic acid esters, (poly) hydroxyphenylalkylketones or (poly) hydroxyphenylarylketone 1,2-quinonediazidesulfonic acid esters, bis [(poly) hydroxyphenyl] alkanes 1,2-quinonediazidesulfonic acid Esters and the like can be mentioned.

The specific novolac resin used in the positive resist of the present invention is synthesized by polycondensing specific phenols and aldehydes in the presence of an acid catalyst.

Specific phenols used at this time are m-cresol, p-cresol, 2,3-xylenol, 2,4-
It is at least one phenol selected from xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol, 2,3,5-trimethylphenol, resorcinol and 2-methylresorcinol. Here, the amount of the other phenols used relative to the total amount of m-cresol and the other phenols is a significant amount,
That is, it is an amount that causes a significant difference when used in combination, and can be, for example, 30 mol% or more.

The other phenols may be used alone or in combination of two or more.

Examples of aldehydes include formaldehyde,
Paraformaldehyde, acetaldehyde, propylaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropylaldehyde, β-phenylpropylaldehyde, o-hydroxybenzaldehyde,
m-hydroxybenzaldehyde, p-hydroxybenzaldehyde, o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o
-Nitrobenzaldehyde, m-nitrobenzaldehyde, p-nitrobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, pn
-Butylbenzaldehyde and the like. Of these compounds, formaldehyde, acetaldehyde, benzaldehyde and the like are preferable. These aldehydes are
They may be used alone or in combination of two or more. The amount of aldehyde used is preferably 0.7 to 3 mol, and particularly preferably 0.7 to 2 mol, per 1 mol of the specific phenol.

As the acid catalyst, inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid, or organic acids such as formic acid, oxalic acid and acetic acid are used. The amount of these acid catalysts used is preferably 1 × 10 ^{−4 to} 5 × 10 ⁻¹ mol per mol of phenols.

In the polycondensation, water is usually used as the reaction medium, but when the phenols used in the polycondensation do not dissolve in the aqueous solution of aldehydes and become a heterogeneous system from the initial stage of the reaction, a hydrophilic solvent is used as the reaction medium. Can also be used. Examples of the hydrophilic solvent used at this time include alcohols such as methanol, ethanol, propanol and butanol, and cyclic ethers such as tetrahydrofuran and dioxane.

The amount of these reaction media used is preferably the reaction raw material 10.
It is 20 to 1000 parts by weight per 0 parts by weight.

The reaction temperature of polycondensation can be appropriately adjusted depending on the reactivity of the reaction raw materials, but is usually 10 to 200 ° C, preferably 70 to 150 ° C.

After completion of the polycondensation, in order to remove the unreacted raw materials, the acid catalyst and the reaction medium existing in the system, the internal temperature is generally set to 130 to
The temperature is raised to 230 ° C., the volatile matter is distilled off under reduced pressure, and then the molten specific novolac resin is drowned on a steel belt or the like and collected.

After completion of polycondensation, the reaction mixture is dissolved in the hydrophilic solvent and added to a precipitating agent such as water, n-hexane or n-heptane to precipitate a specific novolac resin, and the precipitate is separated and dried by heating. It can also be collected by a method.

These specific novolac resins are used alone or in combination of two or more.

When the resist of the present invention is applied to a substrate, the resist of the present invention is dissolved in a suitable solvent so that the concentration is, for example, 5 to 50% by weight, and the resist is spin-coated, flow-coated, roll-coated, or the like to form a silicon film. Apply to wafers, etc. As the solvent used at this time, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, methyl 2-oxypropionate, 2-
Examples thereof include ethyl oxypropionate, toluene, xylene, methyl ethyl ketone, cyclohexanone, ethyl acetate and butyl acetate. These solvents can be used alone or
Used in combination of more than one species. If necessary, benzyl ethyl ether, dihexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonylacetone, isophorone,
Caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-
A high boiling point solvent such as butyrolactone, ethylene carbonate, propylene carbonate or phenyl cellosolve acetate can be added.

A sensitizer may be added to the resist of the present invention in order to improve sensitivity.

Further, the resist of the present invention may contain a surfactant or the like in order to improve coatability, for example, developability of a radiation irradiated portion after striation or formation of a dry coating film.

In addition, the resist of the present invention contains a colorant for visualizing a latent image in a radiation-irradiated portion and a colorant for reducing the effect of halation during radiation irradiation, and an adhesion aid for improving adhesiveness. You can also

Further, the resist of the present invention may contain a storage stabilizer, a defoaming agent, etc., if necessary.

The resist of the present invention is prepared by dissolving a specific novolac resin, a specific 1,2-quinonediazide compound and various compounding agents in a predetermined amount in a solvent and filtering the solution with a filter having a pore size of about 0.2 μm.

Examples of the developer for the resist of the present invention include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, Methyldiethylamine, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, 1,8-diazabicyclo (5,4,0) -7-undecene, 1,5-diazabicyclo (4 , 3,0) -5-
An alkaline aqueous solution prepared by dissolving nonane or the like is used.

Further, a water-soluble organic solvent such as methanol,
An aqueous solution containing an appropriate amount of alcohol such as ethanol or a surfactant may be used as the developing solution.

(Examples) The present invention will be described in detail below with reference to Examples.

Example 1 (1) In a 500 ml separable flask equipped with a stirrer, a dropping funnel and a thermometer, 2, 3, 4, 2 ', 6'in the dark.
-Pentahydroxybenzophenone 11.2 g and 1,2-naphthoquinone diazide-5-sulfonic acid chloride (hereinafter referred to as "NQD") 34.5 g were charged at a molar ratio of 1: 3, and further 240 g of dioxane was added to this solution.
Was added and dissolved by stirring. Separately, 14.3 g of triethylamine was charged into the dropping funnel. The separable flask was immersed in a water bath adjusted to 30 ° C., and when the internal temperature became constant at 30 ° C., triethylamine was added to this solution at an internal temperature of 3
It was slowly added dropwise so as not to exceed 5 ° C. Then, the precipitated triethylamine hydrochloride was removed by filtration, and the filtrate was poured into a large amount of dilute hydrochloric acid to give 2,3,4,2 ′,
6'-Pentahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid triester was precipitated. The 1,2-quinonediazide compound collected by filtration was dried overnight in a vacuum dryer adjusted to 40 ° C.
The yield was 98%.

(2) m-cresol / p-cresol = 6/4 (molar ratio) in a 300 ml separable flask equipped with a stirrer and protected from light.
20 g of the novolak resin obtained by polycondensing mixed cresol of 1. with formaldehyde, the above 2, 3, 4, 2 ',
6'-pentahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid triester 5 g,
60 g of ethyl cellosolve acetate and 15 g of γ-butyrolactone were added and well dissolved at room temperature with stirring. After dissolution, the mixture was filtered through a membrane filter having a pore size of 0.2 μm to prepare a solution of the composition of the present invention. This solution was spin-coated on a silicon oxide film wafer with a spinner, then at 90 ° C for 2
It was prebaked for a minute to form a resist layer having a thickness of 1.2 μm. Then, it was exposed for 0.45 seconds through a pattern mask using a stepper, and developed for 60 seconds with a 2.2 wt% aqueous solution of tetramethylammonium hydroxide (hereinafter referred to as "TMA"). When the obtained resist pattern was observed with a scanning electron microscope, a portion that could not be completely developed, that is, an undeveloped portion was not observed at the joint between the substrate and the resist pattern, and a resist pattern having a line width of 0.8 μm could be resolved.

Comparative Example 1 2,3,4,4′-tetrahydroxybenzophenone-1 was used instead of 2,3,4,2 ′, 6′-pentahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid triester. A solution of the resist composition was prepared in the same manner as in Example 1 (2) except that 2,2-naphthoquinonediazide-5-sulfonic acid triester was used. Using this solution, exposure was performed for 0.65 seconds through a pattern mask using a stepper in the same manner as in Example 1 (2), and TM
It was developed for 60 seconds with an A2.4% by weight aqueous solution. When the obtained resist pattern was observed with a scanning electron microscope, it was possible to resolve a line width up to 1.0 μm, but residual development was observed at the portion where the resist pattern and the substrate were in contact.

Comparative Example 2 Instead of 2,3,4,2 ′, 6′-pentahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid triester in Example 1 (2),
2,3,4,2 ', 4'-pentahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid triester was used, and m-cresol / p-cresol = 6/4 (molar ratio) was mixed. Instead of the novolak resin obtained by polycondensing cresol with formaldehyde, m
-A solution of the composition of the present invention was prepared in the same manner as in Example 1 (2) except that a novolak resin obtained by polycondensing cresol with formaldehyde was used.

This solution was exposed through a pattern mask using a stepper in the same manner as in Example 1 (2) for the exposure time shown in Table 2, and developed with a 2.4% by weight aqueous solution of TMA. When the obtained resist pattern was observed with a scanning electron microscope, it was possible to resolve a line width up to 1.2 μm, but residual development was observed at the portion where the resist pattern and the substrate were in contact.

Examples 2-5 2,4,6,3 ', 4', 5'-hexahydroxybenzophenone, 2,3,4,3 ', 4', 5'-hexahydroxybenzophenone, 2,3,4,5 , 4'-pentahydroxybenzophenone or 2,3,4,3 ',
4 ', 5'-hexahydroxy-5-methylbenzophenone, NQD, triethylamine and dioxane are shown in Table 1 in the same manner as in Example 1 (1).
A quinonediazide compound was synthesized. Then these 1,
A 2-quinonediazide compound and a novolak resin obtained by polycondensing mixed cresol of m-cresol / p-cresol = 4/6 (molar ratio) with formaldehyde were used. Others were the same as in Example 1 (2). To prepare a solution of the composition of the present invention.

Using this solution, a stepper was used through a pattern mask in the same manner as in Example 1 (2) to perform exposure for the number of exposure seconds shown in Table 1, and development was performed for 60 seconds with a TMA 2.4 wt% aqueous solution.
When the obtained resist pattern was observed with a scanning electron microscope, the resolution of the resist pattern was high as shown in Table 1, and no residual development was observed.

Examples 9 to 17 In Example 1 (2), instead of the novolac resin obtained by polycondensing mixed cresol of m-cresol / p-cresol = 6/4 (molar ratio) with formaldehyde, the results are shown in Table 2. Using a novolac resin obtained by polycondensing mixed cresol of the mixing ratio shown with formaldehyde,
Otherwise in the same manner as in Example 1 (2), a solution of the composition of the present invention was prepared. Using this solution, a stepper was used in the same manner as in Example 1 (2) through a pattern mask to perform exposure for the number of exposure seconds shown in Table 2, and a TMA 2.4 wt% aqueous solution was used for 60 seconds.
Developed for seconds. When the obtained resist pattern was observed with a scanning electron microscope, the resolution of the resist pattern was high as shown in Table 2, and no development residue was observed.

Examples 18 to 20 In a 500 ml separable flask equipped with a stirrer, a dropping funnel and a thermometer, protected from light with 2, 3, 4, 3 ', 4',
5'-hexahydroxybenzophenone (hereinafter "HHB
P ”. ), NQD, triethylamine and dioxane were used in the proportions shown in Table 3, respectively, and the 1,2-quinonediazide compound was synthesized in the same manner as in Example 1 (1). Then, these 1,2-quinonediazide compounds and m-cresol / p-cresol = 4/6
A solution of the composition of the present invention was prepared in the same manner as in Example 1 (2), except that a novolak resin obtained by polycondensing mixed cresol (molar ratio) with formaldehyde was used. This solution was exposed through a pattern mask using a stepper in the same manner as in Example 1 (2) for the number of exposure seconds shown in Table 3, and developed with an aqueous TMA solution having each concentration shown in Table 3 for 60 seconds. When the obtained resist pattern was observed with a scanning electron microscope, the resolution of the resist pattern was high as shown in Table 3, and no residual development was observed.

(Effects of the Invention) The positive resist for producing an integrated circuit of the present invention is one in which a specific novolac resin and a specific 1,2-quinonediazide compound are blended, whereby a resist having good developability and a line width of 1 μm or less is obtained. It is possible to achieve high resolution capable of resolving patterns.

The positive resist for producing an integrated circuit of the present invention is highly sensitive to ultraviolet rays, far ultraviolet rays, X-rays, electron beams, molecular beams, γ rays, synchrotron radiation, and proton beam rays, and has a high degree of integration. It is suitable for production.

Front Page Continuation (72) Inventor Yoshiyuki Harada 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (56) Reference JP-A-58-150948 (JP, A) JP-A-58 -17112 (JP, A)

Claims (1)

[Claims] 1. M-cresol and a significant amount of p-cresol, 2,3-xylenol, 2,4-xylenol,
2,5-xylenol, 3,4-xylenol, 3,5
-Xylenol, 2,3,5-trimethylphenol,
The following formula (I) is used for 100 parts by weight of an alkali-soluble novolac resin synthesized by polycondensing at least one phenols selected from resorcinol and 2-methylresorcinol and aldehydes in the presence of an acid catalyst. (In the formula, R _{1 to} R ₁₀ are the same or different, a hydroxyl group,
A hydrogen atom or a methyl group, and the number of hydroxyl groups in the formula is 5 ≦≦ 10) and a 1,2-quinonediazide sulfonic acid halide in the presence of a basic catalyst. A positive resist for producing an integrated circuit, comprising 5 to 100 parts by weight of a 1,2-quinonediazide compound obtained by reacting.