JPH0934116A - Water-soluble pattern forming material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of microbubbles owing to superior defoaming property and to prevent the occurrence of pattern defects in a formed water-soluble film by adding one or more kinds of specified water-soluble compds. SOLUTION: One or more kinds of water-soluble compds. selected from among polyhydric alcohol, monoalkyl ether of polyhydric alcohol, alkylene oxide adduct of monoalkyl ether of polyhydric alcohol, hydroxycarboxylic acid and alkyl ester of hydroxycarboxylic acid are added by 0.00001-30 pts.wt., especially 0.001-10 pts.wt. based on 100 pts.wt. water. In order to improve film forming property, various water-soluble high molecular compds. as well as an acetylene alcohol compd. are preferably added. The high molecular compds. include PVA, its ether deriv., polyacrylic acid and its ester deriv.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pattern forming material for photolithography using a photoresist film, and more particularly to a water-soluble pattern forming material used in a process of forming a water-soluble film on an upper layer of a photoresist film. .

[0002]

2. Description of the Related Art As semiconductor integrated circuits have become highly integrated and highly densified, it has become necessary to improve the precision of various strict pattern dimensions in the pattern forming process.

As is well known, a method generally called photolithography is used for forming various fine patterns. In this method, a photoresist film is formed on a substrate by a method such as spin coating, a mask pattern is transferred to the photoresist film by a subsequent exposure step and a development step, and then a pattern is formed on the substrate by an etching step. is there. As an exposure machine used in this method, a reduction projection exposure machine (stepper) is generally used in order to reduce the pattern size and increase the accuracy of the pattern size in the pattern forming process.

However, in the method using only the photoresist film as described above, it becomes difficult to maintain satisfactory dimensional stability as the pattern dimension is reduced and the accuracy is increased. One of the causes is the problem of a decrease in the depth of focus due to the reduction of the pattern size. In order to solve this problem, there is a method of providing a contrast enhancing film on a photoresist film, and this method is a contrast enhancing photolithography (CEL: Contras) method.
t Enhancement Lithography
Or Contrast Enhancement La
known as yer). The contrast enhancing film used here is disclosed in European Patent Publication Nos. 361627 and 3
As disclosed in US Pat. No. 55,934, U.S. Pat. No. 4,702,996, etc., it contains a photobleaching compound such as an aryl nitrone compound and a polymerizing binder, and discolors by light.

As another cause, in the method using only the photoresist film, light exposure, that is, standing wave occurs in the photoresist film because the exposure is performed with a single wavelength in the exposure process. That can be mentioned.
In other words, the light in the exposure process first enters the photoresist film, is then reflected from the substrate, and is further reflected / passed at the interface between the photoresist film and the air. When the thickness changes, the reflectance at the interface between the photoresist film and air changes. At the step of the reflectivity, the film thickness of the photolithography fluctuates, and thus the fluctuation of the film thickness changes the exposure amount, and the fluctuation of the pattern size lowers the dimensional accuracy.

As a method for solving these problems caused by the unevenness of the substrate surface and performing good patterning, a transmissive antireflection film ARCOR: Anti Reflect
live Coat On Resist (Japanese Patent Laid-Open No. 62-
No. 62520) has been proposed. This method is a method of providing a predetermined film on the upper layer of the photoresist film. In this case, if the mixing layer with the photoresist film is not formed and the conventional equipment can be used, the photoresist film It is desirable that the predetermined film of the upper layer is formed of a water-soluble pattern forming material.

Further, in place of the novolak resin or naphthoquinone diazide photosensitizer type resist material used for i-line exposure in the photoresist film, a chemically amplified resist material used for far ultraviolet ray exposure such as KrF excimer laser is used. When formed, if the exposure time after exposure to post-exposure bake (PEB) becomes long,
There is also a problem that a refractory layer is generated on the surface of the resist film which is in contact with air, and an eaves is generated in the resist profile after development.

In order to solve this problem, a method of forming a protective film on the resist film has been proposed (Japanese Patent Laid-Open No. Hei 4 (1999) -411).
-221814). In the case of this method, for example, in order to peel off the CEL film, the antireflection film or the upper protective film without adding a conventional device, it is most preferable to peel off using a developing unit. In this case, since the solution used in the developing unit for the positive type photoresist film is the alkaline aqueous solution which is the developing solution and the pure water which is the rinse solution, the CEL film material and the antireflection film material which can be easily peeled by these solutions. And an upper protective film material is desirable. As such a material, for example, an aqueous alkaline solution-soluble nitrone-containing water-soluble contrast enhancing film described in JP-A-5-208949, an antireflection film described in JP-A-6-51523, and JP-A-4-221814 are disclosed. A water-soluble pattern forming material such as a resist upper protective film described in the publication has been proposed.

However, a common drawback of these water-soluble pattern forming materials is that bubbles are generated, and when the water-soluble pattern forming material is spin-coated to form a film, the bubbles burst and cause striation. Or, bubbles may be trapped in the formed water-soluble film and cause circular pattern defects. Such bubbles can be classified into bubbles generated on the surface of the aqueous solution and bubbles generated in the aqueous solution, but in this case, the problem is bubbles, especially microbubbles of micron order size, which are defoamed. However, it is very important to suppress the occurrence thereof in reducing pattern defects.

As defoaming agents for general aqueous solutions, natural oils and fats such as soybean oil, corn oil, olive oil, linseed oil, castor oil and lard oil, long chain alcohols such as amyl alcohol and octyl alcohol, silicone resin Classes and the like are known, but these have low hydration property or do not hydrate at all. Therefore, when the water-soluble pattern forming material containing the above defoaming agent is spin-coated, coating unevenness occurs and a uniform film cannot be formed. Therefore, there is a demand for an antifoaming agent having a high hydration property and capable of forming a uniform film by spin coating even when added to a water-soluble pattern forming material.

The present invention has been made in view of the above circumstances, and suppresses the generation of microbubbles due to its excellent defoaming property, and has a high hydratability, and is well dissolved in water or an aqueous solution such as a water-soluble polymer aqueous solution. An antifoaming agent capable of suppressing the occurrence of striation and coating unevenness after spin coating is added, and an object thereof is to provide a water-soluble pattern forming material that prevents the occurrence of pattern defects in the formed water-soluble film. To do.

[0012]

Means for Solving the Problems and Modes for Carrying Out the Invention The present inventor has conducted extensive studies to achieve the above-mentioned object, and found that polyhydric alcohol, monoalkyl ether of polyhydric alcohol, polyhydric alcohol or monoalkyl thereof. Alkylene oxide adduct of ether, hydroxycarboxylic acid,
In addition, it is found that a water-soluble compound selected from hydroxycarboxylic acid alkyl esters has a sufficient effect also on the defoaming of bubbles, particularly microbubbles having a size of submicron to several microns, and these water-soluble compounds are In particular, it has high hydration property, dissolves well in water or water-soluble polymer aqueous solution, and if this is added to the water-soluble pattern forming material, the occurrence of striations and coating unevenness after spin coating is suppressed, and pattern defects are generated. It was discovered that the above can be prevented, and the present invention has been completed.

The present invention will be described in more detail below. The water-soluble pattern forming material of the present invention is a polyhydric alcohol, a polyalkyl alcohol monoalkyl ether, a polyhydric alcohol or an alkylene oxide adduct of the monoalkyl ether, One or two or more water-soluble compounds selected from hydroxycarboxylic acids and hydroxycarboxylic acid alkyl esters are added.

Here, as the polyhydric alcohol, dihydric alcohols such as ethylene glycol, 1,2-propanediol and 1,3-propanediol, glycerin, 1,
Trihydric alcohols such as 2,4-butanetriol are mentioned, and those having no aliphatic unsaturated bond are preferably used. Examples of monoalkyl ethers of polyhydric alcohols include monoalkyl ethers of the above polyhydric alcohols having 1 to 8 carbon atoms, such as propylene glycol monoethyl ether (ethoxypropanol) and ethylene glycol monomethyl ether. Examples of these alkylene oxide adducts include ethylene oxide and / or propylene oxide adducts, in which case the alkylene oxide addition mole number is 1 to 3
It is preferably 0, particularly preferably 1 to 10. Furthermore, examples of the hydroxycarboxylic acid and its alkyl ester include lactic acid, oxylactic acid, and the like, and alkyl esters thereof having 1 to 8 carbon atoms, such as ethyl lactate.

In order to achieve the object of the present invention, the amount of the water-soluble compound added is 0.000 with respect to 100 parts by weight of water.
It is from 01 to 30 parts by weight, particularly from 0.001 to 10 parts by weight. The water used is preferably pure water or distilled water.

In order to improve the film-forming property of the water-soluble pattern forming material of the present invention, it is preferable to add various water-soluble polymer compounds in addition to the above acetylene alcohol compound. Examples of such water-soluble polymer compounds include polyvinyl alcohol and its ether derivatives, polyacrylic acid and its ester derivatives, polymethacrylic acid and its ester derivatives, polyvinylpyrrolidone, polyethylene oxide, amylose, dextran, cellulose and pullulan. These can be added alone or as a mixture containing two or more kinds in an arbitrary ratio or as a copolymer containing two or more kinds in an arbitrary ratio. Even with 0.1 to 30 parts by weight with respect to 100 parts by weight of water
It is suitable to set it as a weight part, Preferably it is 0.5-10 weight part. Outside the above range, it may not be possible to form a uniform film.

The water-soluble pattern forming material of the present invention may optionally be added with various surfactants in order to improve the film-forming property by further improving the wettability and the leveling property. As such a surfactant, it is desirable that the hydrophobic group is made of fluorine carbide. This is because the surfactant having a hydrophobic group made of fluorocarbon has a larger effect of reducing the surface tension and improving the leveling property in the water-soluble pattern forming material than the surfactant having a hydrophobic group made of hydrocarbon or organopolysiloxane. In addition, JP-A-6-51
As described in Japanese Laid-Open Patent Publication No. 523/523, by incorporating a fluorine-based surfactant, its refractive index can be lowered and the antireflection effect can be enhanced. The amount of these surfactants added is 0.00001 to 100 parts by weight of water.
20 parts by weight, preferably 0.001 to 10 parts by weight is suitable. If the addition amount is less than 0.00001 parts by weight, wettability and leveling property may not be improved, and if the addition amount exceeds 20 parts by weight, mixing with other layers (for example, resist film) may occur, and development may be difficult. Later patterns may be distorted or cause pattern defects.

When the water-soluble pattern forming material of the present invention is used as a material for a contrast enhancing film, an alkaline aqueous solution soluble aryl nitrone compound represented by the following general formula (1) is added to water 100 in addition to the above additives. It is preferable to add 1 to 30 parts by weight to parts by weight. If it is less than 1 part by weight, the contrast enhancing effect may be extremely small, and if it exceeds 30 parts by weight, it may be difficult to form a uniform film.

[0019]

Embedded image (Wherein R ¹ , R ² and R ³ are the same or different alkyl groups, aryl groups or hydrogen atoms, R ⁴ , R ⁵ ,
R ⁶ , R ⁷ and R ⁸ are the same or different alkyl groups,
Is a hydrogen atom or -COOH, at least one of R ⁴ to R ⁸ is -COOH. X is an alkoxy group, R ¹¹ dialkylamino group or a hydrogen atom represented by R ¹² N-represented by R ¹⁰ O-, R ¹⁰ is an alkyl group, R ¹¹ and R ¹²
Are the same or different alkyl groups. q is 0, 1
Or 2. )

Here, each of the above alkyl groups has 1 to 1 carbon atoms.
8, especially 1 to 4 are preferable, and the same applies to the alkyl group of the dialkylamino group. Aryl group has 6 to 1 carbon atoms
0, especially 6-8 are preferable, and the alkoxy group has 1-8 carbon atoms, especially 1-4 carbon atoms.

As described above, when the water-soluble pattern forming material of the present invention is used as a material for a contrast enhancing film, in order to improve the solubility of the above-mentioned alkaline aqueous solution soluble aryl nitrone compound in water, various kinds of materials are further added. An organic base can be added, and as such an organic base, for example, tris (hydroxymethyl) aminomethane, pyridine, triethylamine, tetramethylammonium hydroxide solution, tetraethylammonium hydroxide solution, 2,
2 ′, 2 ″ -nitrotriethanol, triethylenediamine (DABCO) and the like can be mentioned. These can be added alone or in combination of two or more, and the water-soluble pattern formation of the present invention can be performed. The amount of the organic base added to the material is preferably 1 to 30 parts by weight with respect to 100 parts by weight of water. If it exceeds, the pattern shape after development may deteriorate due to mixing with the surface of the photoresist film.

The method for preparing the water-soluble pattern forming material of the present invention is not particularly limited as long as it can uniformly dissolve each of the above components in water, preferably pure water, and it is prepared by a conventional method. be able to.

The water-soluble pattern forming material of the present invention is preferably used as a material used in the process of forming a water-soluble film as a protective film on the upper layer of a photoresist film, and is particularly excellent in defoaming property. Moreover, due to its high hydration property, not only the generation of micro bubbles during spin coating is suppressed, but also striations and uneven coating after spin coating are also suppressed, effectively preventing the occurrence of pattern defects. can do.

[0024]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 5 parts by weight of polyvinyl alcohol having an average molecular weight of 1000 and a saponification degree of 88% was added to 100 parts of pure water.
0.1 parts by weight of a fluorine-based surfactant represented by the following formula (2) and 0.1 parts by weight of ethyl lactate were added to prepare an aqueous solution for resist overcoating.
It was filtered with a Teflon filter having a diameter of 5 μm and left for one day.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

[0027] _{CF 3 - (CF 2) 8} -COO - (CH 3) 4 NH + ... (2)

Example 2 5 parts by weight of polyvinyl alcohol having an average molecular weight of 1000 and a saponification degree of 88% was added to 100 parts of pure water.
0.1 parts by weight of the fluorine-based surfactant represented by the above formula (2) and 0.1 parts by weight of ethylene glycol were added to prepare an aqueous solution for resist overcoating, and the solution having a diameter of 0.05 μm was prepared. Filter with Teflon filter, 1
I left it all day and night.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

Example 3 5 parts by weight of polyvinyl alcohol having an average molecular weight of 1000 and a saponification degree of 88% was added to 100 parts of pure water.
0.1 parts by weight of a fluorine-based surfactant represented by the above formula (2) and 0.1 parts by weight of ethylene glycol monomethyl ether were added to prepare a resist overcoat aqueous solution having a concentration of 0.05 μm. It was filtered with a Teflon filter of the same diameter and left for one day.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

Example 4 5 parts by weight of polyvinyl alcohol having an average molecular weight of 1000 and a saponification degree of 88% was added to 100 parts of pure water.
0.1 parts by weight of the fluorine-containing surfactant represented by the above formula (2) and 0.1 parts by weight of glycerin were added to prepare a resist overcoating aqueous solution.
It was filtered with a Teflon filter having a diameter of 5 μm and left for one day.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

Example 5 4.5 parts by weight of aryl nitrone represented by the formula (3) and tris (hydroxymethyl) aminomethane represented by the formula (OHCH ₂ ) ₃ CNH ₂ 2.0
Luvi is a copolymer of 60 parts by weight of polyvinylpyrrolidone and 40% of ethyl polyacrylate.
3.5 parts by weight of scolVA-64 (manufactured by BASF) and 0.1 parts by weight of the fluorine-containing surfactant represented by the above formula (2) were dissolved in 90 parts by weight of pure water to prepare ethyl lactate 0.1%.
By adding 1 part by weight, an aqueous solution for a water-soluble contrast enhancing film was prepared, filtered with a Teflon filter having a diameter of 0.05 μm, and left standing overnight.

[0035]

Embedded image

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

Example 6 4.5 parts by weight of the aryl nitrone represented by the above formula (3) and the formula (OHCH ₂ ) ₃ CNH ₂
2.0 parts by weight of tris (hydroxymethyl) aminomethane represented by formula (3), 3.5 parts by weight of pullulan having an average molecular weight of 2000, and the fluorine-based surfactant represented by the formula (2):
1 part by weight is well dissolved in 90 parts by weight of pure water, 0.1 part by weight of ethylene glycol is added to prepare an aqueous solution for a water-soluble contrast enhancing film, which is filtered with a Teflon filter having a diameter of 0.05 μm and left for one day. I left it.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

Comparative Example 1 5 parts by weight of polyvinyl alcohol having an average molecular weight of 1000 and a saponification degree of 88% was added to 100 parts of pure water.
It is dissolved in 1 part by weight, 0.1 part by weight of the fluorine-containing surfactant represented by the above formula (2) is added to prepare an aqueous solution for resist overcoat, and the solution is filtered through a Teflon filter with a diameter of 0.05 μm. I left it.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

[Comparative Example 2] 5 parts by weight of polyacrylic acid having an average molecular weight of 2000 and 5 parts by weight of tetramethylammonium perfluorooctanoate were dissolved in 100 parts by weight of pure water to prepare an aqueous solution for antireflection film. It was filtered with a Teflon filter having a diameter of 0.05 μm and left for one day.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

[Comparative Example 3] 4.5 parts by weight of the aryl nitrone represented by the above formula (3) and the formula (OHCH ₂ ) ₃ CNH ₂
Trade name L which is a copolymer of 2.0 parts by weight of tris (hydroxymethyl) aminomethane, 60% of polyvinylpyrrolidone and 40% of ethyl polyacrylate.
3.5 parts by weight of uviscol VA-64 (manufactured by BASF), and a fluorosurfactant 0.1 represented by the above formula (2).
By dissolving 90 parts by weight of pure water in 90 parts by weight of water, an aqueous solution for a water-soluble contrast enhancing film was prepared, filtered through a Teflon filter having a diameter of 0.05 μm, and allowed to stand overnight.

Then, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor.

[Comparative Example 4] 4.5 parts by weight of the aryl nitrone represented by the above formula (3) and the formula (OHCH ₂ ) ₃ CNH ₂
2.0 parts by weight of tris (hydroxymethyl) aminomethane represented by formula (3), 3.5 parts by weight of pullulan having an average molecular weight of 2000, and the fluorine-based surfactant represented by the formula (2):
1 part by weight was well dissolved in 90 parts by weight of pure water to prepare an aqueous solution for a water-soluble contrast enhancing film, which was filtered through a Teflon filter having a diameter of 0.05 μm and left for one day.

After that, microbubbles were measured with an in-liquid particle counter: KL-22 manufactured by Rion. Also,
Dispense on a silicon wafer in a clean atmosphere of class 100 or less, and 1000 rpm for 5 seconds, 2000
Spin coating was performed for 30 seconds at rpm, and defect measurement was performed using Surfscan 4500 manufactured by Tencor. The above results are shown in Tables 1 and 2.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

INDUSTRIAL APPLICABILITY The water-soluble pattern forming material of the present invention is useful as a material for forming a protective film as an upper layer of a photoresist film in pattern formation by a photolithography method using a photoresist film, and particularly, its excellent defoaming property. Property and high hydration property, it is possible to prevent the occurrence of pattern defects, and it becomes possible to easily form a fine pattern without adding conventional equipment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshinobu Ishihara 28-1, Nishi-Fukushima, Chugiki-mura, Nakakubiki-gun, Niigata Prefecture Synthetic Technology Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Satoshi Okazaki Matsuida-cho, Usui-gun, Gunma Hitomi No. 1 10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Mitsuo Umemura Osamu Matsuida Town, Usui District, Gunma Prefecture Hitomi No. 1 10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (2)

[Claims] 1. One of water-soluble compounds selected from polyhydric alcohols, monoalkyl ethers of polyhydric alcohols, alkylene oxide adducts of polyhydric alcohols or monoalkyl ethers thereof, hydroxycarboxylic acids, and hydroxycarboxylic acid alkyl esters. Or 2 or more kinds of water 1
A water-soluble pattern forming material, wherein 0.00001 to 30 parts by weight is added to 100 parts by weight. 2. The water-soluble pattern forming material according to claim 1, further comprising a water-soluble polymer compound.