JP2878150B2 - Coating solution for resist and resist material using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel resist coating solution and a resist material using the same, and more particularly, to the multiple interference of light in a photoresist film when a pattern is formed by photolithography. The present invention relates to a resist coating solution used for forming an anti-interference film capable of preventing a decrease in the precision of a resist pattern by reducing the resist pattern, and a resist material having an anti-interference film formed of this coating solution formed on the surface of a photoresist film.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a photoresist film is provided on a substrate such as a silicon wafer and selectively irradiated with active light such as ultraviolet rays, far ultraviolet rays, excimer lasers, X-rays, and electron beams. Photolithography technology is used to form a resist pattern on a substrate by exposing to light and developing. As the photoresist, a negative photoresist in which an active light-irradiated portion is dissolved and removed at the time of development and a positive photoresist in which an active light-irradiated portion is dissolved and removed at the time of development are appropriately selected and used according to the intended use. Have been.

With the improvement in the degree of integration of semiconductor devices, semiconductor device manufacturing apparatuses suitable for fine processing have been researched and developed. For example, an exposure apparatus for actinic rays is also required to use g-line, i-line, excimer laser, etc. An exposure apparatus using a wavelength has been widely used in recent years.

In the formation of a resist pattern by the photolithography, it is known that multiple interference of light occurs in the photoresist film, and that the dimension width of the resist pattern varies with the variation of the photoresist film thickness. This multiple interference of light is caused by the fact that the irradiation light of a single wavelength incident on the photoresist film formed on the substrate interferes with the reflected light from the substrate, and the amount of light energy absorbed in the thickness direction of the photoresist film differs. The variation in the thickness of the photoresist affects the dimension width of the resist pattern obtained after the development, and as a result, the dimension precision of the resist pattern is reduced. The reduction in the dimensional accuracy of the resist pattern is a serious problem particularly when a fine pattern is formed on a substrate having a step, since the photoresist film thickness is necessarily different in the uneven portions of the step.
Therefore, there is a demand for the development of a technique that eliminates the above-described interference effect and does not reduce the pattern dimensional accuracy even in a fine pattern formed on a substrate having a step.

Conventionally, as a means for reducing such an interference effect, a method of forming an antireflection film on a substrate surface (US Pat. No. 4,910,122) or a method of forming an antireflection film on a photoresist film provided on a substrate is proposed. Polysiloxane as an anti-reflection film,
A method of forming a water-soluble resin film such as polyvinyl alcohol has been proposed (Japanese Patent Publication No. 4-55323,
JP-A-3-222409, etc.). However,
The former method of forming an anti-reflection film on the substrate surface can reduce the interference effect to some extent, but when mask alignment is performed using light of the same wavelength as the exposure light, the mask alignment detection signal is also weakened by the anti-reflection film. However, there is a drawback that mask alignment is difficult. In addition, it is necessary to transfer the resist pattern to the anti-reflection film with high precision, and after the transfer, the anti-reflection film must be removed by etching or the like without affecting the element, so that the number of working steps is not increased. However, it is not necessarily applicable to all substrate processing. On the other hand, the latter method of forming an antireflection film on a photoresist film is practical without a complicated process, but has a problem that the effect of preventing interference is not sufficient. In particular, when forming a fine pattern, even a slight interference effect has a large effect on the pattern dimensional accuracy. At present, there is a strong demand for the development of anti-interference films.

Incidentally, the anti-interference film is formed on the photoresist film by applying a resist coating solution onto the photoresist film using a coating apparatus such as a spin coater. Therefore, from the viewpoint of preventing corrosion of equipment such as a coating apparatus, a resist coating liquid capable of finally adjusting the pH to neutral has been demanded. In this regard, for example, an antireflection coating comprising a water-processable film-forming fluorine-containing composition has been proposed in, for example, JP-A-5-188598,
Fluorocarbon compounds disclosed in this publication as this fluorine-containing composition include perfluoroalkyl acids and ammonium salts of perfluoroalkylsulfonic acids,
And tetramethylammonium salts. However,
Since the resist coating solution obtained using these compounds is inclined toward the acidic side (pH about 2 to 4), there is a problem that equipment such as a coating apparatus is susceptible to corrosion by acid. Even if the resist coating solution is made to be in a neutral state, the formed fluorocarbon compound salt is gelled or completely insoluble, and is precipitated.
A resist coating solution in a neutral state cannot be formed. Under these circumstances, there is a demand for the development of a resist coating solution that can maintain the effect of an antireflection film and also prevent corrosion of equipment such as a coating device.

In the interference prevention film formed on the photoresist film, in addition to the above-described reduction of the multiple interference of light in the photoresist film, the interference prevention film is formed in order to prevent a decrease in the resist pattern dimensional accuracy. It is necessary to achieve uniformity of the coating film and to eliminate coating unevenness. A conventional resist coating solution, for example, in the case of using a water-soluble film forming component and a fluorine-based surfactant, is usually substantially two
Those consisting only of components were used. However, when these two-component resist coating liquids are applied on a photoresist to form an interference prevention film, the uniformity of the coating film is poor,
There is a problem that coating unevenness is likely to occur. When such coating unevenness occurs, the formed resist pattern becomes a worm-eating state at a portion where the coating unevenness has occurred, and therefore, there is a problem that a resist pattern as a mask pattern cannot be obtained.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances.
To provide a resist coating solution that can prevent corrosion of equipment such as a coating device while maintaining the effect of an antireflection film that can sufficiently cope with miniaturization of processing dimensions in the field of semiconductor device manufacturing in recent years, or In addition, the present invention provides a resist coating solution capable of forming an interference preventing film without coating unevenness by achieving uniformity of the interference preventing film and obtaining a resist pattern according to a mask pattern, and a resist material using these resist coating solutions. Is to provide.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a resist coating solution comprising a water-soluble film-forming component and a specific fluorine-based surfactant or a water-soluble film is used. A resist coating solution comprising a forming component, an optional fluorinated surfactant and an anionic surfactant represented by a specific chemical formula, and a resist obtained by further adding N-alkyl-2-pyrrolidone thereto That the above object can be achieved by the coating solution for the resist, and that the object can be achieved by a double-layered resist material formed by forming an anti-interference film comprising the coating solution for the resist on the surface of the photoresist film. The present inventors have completed the present invention based on these findings.

That is, according to the present invention, in a resist coating solution containing a water-soluble film-forming component and a fluorine-based surfactant, the fluorine-based surfactant has the general formula (I)

[0011]

Embedded image (Wherein, Rf is a fluorinated hydrocarbon group in which some or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms) A salt with an alkanolamine, and a compound of the general formula (I
I)

[0012]

Embedded image (In the formula, R′f is a fluorinated hydrocarbon group in which some or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms.) There is provided a resist coating solution characterized by at least one selected from salts of a compound and an alkanolamine (hereinafter, referred to as “first resist coating solution” for convenience).

Further, according to the present invention, a resist coating solution containing a water-soluble film-forming component and a fluorine-containing surfactant is further provided with a compound represented by the general formula (III):

[0014]

Embedded image (Wherein at least one of R ₁ and R ₂ has 5 to 18 carbon atoms)
Is an alkyl or alkoxy group, the remainder being a hydrogen atom,
An alkyl group or an alkoxy group having 5 to 18 carbon atoms; at least one of R ₃ , R ₄ and R ₅ is an ammonium sulfonate group or a sulfonate-substituted ammonium group, and the remainder is a hydrogen atom, an ammonium sulfonate group or a sulfonate group; A resist coating solution (hereinafter referred to as a “second resist coating solution” for convenience) characterized by adding at least one selected from anionic surfactants represented by substituted ammonium groups). ").

Further, according to the present invention, a resist coating solution containing a water-soluble film-forming component and a fluorine-containing surfactant is further added to the above-mentioned general formula (III)

[0016]

Embedded image (Wherein R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are as defined above) and at least one selected from anionic surfactants represented by the following general formula ( VI)

[0017]

Embedded image (Wherein, R ₁₀ represents an alkyl group having 6 to 20 carbon atoms), and a resist coating solution (hereinafter referred to as “third compound” for convenience) characterized by adding N-alkyl-2-pyrrolidone represented by the following formula: Hereinafter referred to as “resist coating liquid”).

Further, according to the present invention, there is provided a resist material characterized in that an anti-interference film formed of any of the first, second and third resist coating solutions is formed on the surface of a photoresist film. .

The resist coating solution of the present invention and a resist material using the same will be described in detail below.

First, the water-soluble film-forming component used in any of the first, second and third resist coating solutions of the present invention has water solubility and transparency to irradiation light. Any may be used as long as it has, but is not particularly limited, for example, a uniform coating film can be formed by a conventional coating means such as a spin coating method, even when coated on a photoresist film, It is preferable to use a material having characteristics such as not forming a deteriorated layer between the photoresist film and the film, transmitting actinic light sufficiently, and forming a highly transparent film having a small absorption coefficient.

Examples of such a water-soluble film-forming component include hydroxypropyl methylcellulose phthalate,
Cellulose-based polymers such as hydroxypropylmethylcellulose acetate phthalate, hydroxypropylmethylcellulose acetate succinate, hydroxypropylmethylcellulose hexahydrophthalate, hydroxypropylmethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, cellulose acetate hexahydrophthalate, carboxymethylcellulose, ethylcellulose and methylcellulose; N,
N-dimethylacrylamide, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylaminopropylacrylamide, N-methylacrylamide, diacetone acrylamide, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, Acrylic polymers based on N, N-dimethylaminoethyl acrylate, acryloylmorpholine, acrylic acid and the like; vinyl polymers such as polyvinyl alcohol and polyvinylpyrrolidone; and the like. Among these, an acrylic acid-based polymer or polyvinylpyrrolidone, which is a water-soluble polymer having no hydroxyl group in the molecule, is preferable, and polyvinylpyrrolidone is most preferably used. These water-soluble film-forming components may be used alone or in combination of two or more.

In the first resist coating solution of the present invention, in addition to the water-soluble film-forming component, a salt of the compound represented by the general formula (I) with an alkanolamine may be used as a fluorinated surfactant. And at least one selected from salts of the compound represented by the general formula (II) and an alkanolamine as an essential component.

Here, examples of the compound represented by the general formula (I) include perfluoroheptanoic acid and perfluorooctanoic acid, and examples of the compound represented by the general formula (II) include perfluoropropyl Sulfonic acid, perfluorooctyl sulfonic acid, perfluorodecyl sulfonic acid and the like can be mentioned. Specifically, for example, perfluoroheptanoic acid is commercially available as EF-201 and the like, and perfluorooctylsulfonic acid is commercially available as EF-101 and the like (all manufactured by Tochem Products Co., Ltd.). Can be. Among these compounds, perfluorooctyl sulfonic acid is particularly preferred from the viewpoints of interference prevention effect, solubility in water, ease of pH adjustment, and the like.

Examples of the alkanolamine include, for example, monoethanolamine, N-methylethanolamine, N-
Ethylethanolamine, diethanolamine, triethanolamine and the like can be mentioned, and among them, monoethanolamine and the like are preferably used.

As described above, the above-mentioned water-soluble film-forming component includes a salt of the compound represented by the general formula (I) with an alkanolamine and a salt of the compound represented by the general formula (II) with an alkanolamine. Since the pH of the finally obtained resist coating solution can be adjusted to neutral by containing at least one selected from the group consisting of: Can be effectively prevented.

The first resist coating solution of the present invention comprises:
It is usually used in the form of an aqueous solution, and the content of the water-soluble film-forming component is preferably 0.5 to 10.0% by weight.
The content of at least one selected from the salt of the compound represented by the general formula (I) and the alkanolamine and the salt of the compound represented by the general formula (II) and the alkanolamine is 1.0%. Preferably it is 〜15.0% by weight.

The first resist coating solution of the present invention is usually used in the form of an aqueous solution as described above.
When an alcohol-based organic solvent such as isopropyl alcohol is contained, the solubility of the fluorine-based surfactant is improved and the uniformity of the coating film is improved. Therefore, an alcohol-based organic solvent may be added as necessary. The addition amount of the alcohol-based organic solvent is preferably selected within a range of up to 20% by weight based on the total amount of the coating solution. Further, various additives for improving the properties of the coating film can be added to the first resist coating solution of the present invention as desired, as long as the object of the present invention is not impaired.

In the second resist coating solution of the present invention, in addition to the water-soluble film-forming component, any fluorine-based surfactant and an anionic surfactant represented by the above general formula (III) At least one selected from agents is contained as an essential component.

The fluorine-based surfactant used in the resist coating solution is not particularly limited, and any commonly used fluorine-containing surfactant can be used. Is particularly preferably used. As the anionic non-metallic fluorinated surfactant, general formula (IV)

[0030]

Embedded image In the formula, Rf is a fluorinated hydrocarbon group in which part or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms; M is a hydrogen atom or NR ₆ R ₇ R ₈ R ₉ (where R ₆ , R ₇ , R
₈ and R ₉ each independently represent a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms having a hydroxyl group, or a lower alkyl group having 1 to 4 carbon atoms.) Or the general formula (V)

[0031]

Embedded image In the formula, R′f is a fluorinated hydrocarbon group in which part or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms; M is a hydrogen atom or NR ₆ R ₇ R ₈ R ₉ (where R ₆ , R ₇ , R
₈ and R ₉ each independently represent a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms having a hydroxyl group, or a lower alkyl group having 1 to 4 carbon atoms.) Those containing at least one kind can be mentioned. These fluorine atom-containing compounds include, for example, perfluoropropylsulfonic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorooctylsulfonic acid, perfluorodecylsulfonic acid, perfluoroheptanoic acid-ammonium salt, perfluorooctanoic acid- Ammonium salt, perfluorooctylsulfonic acid-ammonium salt, perfluoropropylsulfonic acid-tetramethylammonium salt, perfluoroheptanoic acid-tetramethylammonium salt, perfluorooctylsulfonic acid-tetramethylammonium salt, perfluorodecylsulfonic acid- Tetramethylammonium salt, perfluoropropylsulfonic acid-monoethanolamine salt, perfluorooctanoic acid-monoethanolamine salt, perfluorooctyl Sulfonic acid - monoethanolamine salt, perfluoro decyl acid - monoethanolamine salt and the like. Specifically, for example, perfluorooctylsulfonic acid-ammonium salt is E
Perfluoroheptanoic acid-ammonium salts are commercially available as F-104, Fc-93, etc., EF-204, Fc-143, etc., and perfluorodecylsulfonic acid-ammonium salts, Fc-120, etc., respectively.
EF-104 and EF-204 are manufactured by Tochem Products Co., Ltd., and Fc-93, Fc-143, and Fc-120 are manufactured by Sumitomo 3M Limited. As described above, commercially available products may be used, or they may be easily prepared and obtained.

Among these fluorine atom-containing compounds, compounds represented by the above general formula (I) (here, Rf
Is selected from salts of alkanolamines with alkanolamines, and salts of compounds represented by general formula (II) (where R'f is as defined above) with alkanolamines. At least one of these is preferable because corrosion of equipment such as a coating apparatus can be prevented. Examples of the compound represented by the general formula (I) or (II) include those exemplified in the description of the first resist coating solution.
Perfluorooctylsulfonic acid is particularly preferred because of its solubility in water and ease of pH adjustment. In addition, the alkanolamine also includes those exemplified above, and can be used without any particular limitation. However, monoethanolamine is particularly preferable.

The anionic surfactant is represented by the general formula (I)
II) (wherein R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are as defined above) are selected from diphenyl ether derivatives. In formula (III), at least one of R ₃ , R ₄ and R ₅ is an ammonium sulfonate group or a sulfonate-substituted ammonium group, and the sulfonate-substituted ammonium group is mono-substituted, di-substituted, may be any of trisubstituted and tetrasubstituted ammonium group, examples of the substituent, for example _{-CH 3, -C 2 H 5,} -CH 2 OH, -C 2 H 4 OH
And the like. In the case of a polysubstituted ammonium group, the substituents may be the same or different.

Here, in the general formula (III), R
₁ is an alkyl group or an alkoxy group having a carbon number of 5 to 18; R ₂ is hydrogen atom or an alkyl group or an alkoxy group having a carbon number of 5 to 18; R ₃ is the formula -
SO ₃ NZ ₄ (wherein Z is each independently a hydrogen atom,
An alkyl group having 1 to 2 carbon atoms or 1 to 2 carbon atoms
Or a substituted or unsubstituted ammonium sulfonate group represented by the formula: wherein R ₄ and R ₅ are each a hydrogen atom or a general formula —SO ₃ NZ
₄ (where Z is as defined above)
Preferred is a substituted or unsubstituted ammonium sulfonate group.

Specific examples of the anionic surfactant represented by the general formula (III) include ammonium alkyl diphenyl ether sulfonate, tetramethyl ammonium alkyl diphenyl ether sulfonate, trimethyl ethanol ammonium alkyl diphenyl ether sulfonate, and alkyl diphenyl ether sulfonate. Examples include, but are not limited to, triethylammonium, ammonium alkyldiphenylether disulfonate, diethanolammonium alkyldiphenyletherdisulfonate, tetramethylammonium alkyldiphenyletherdisulfonate. The alkyl group in the above compound has 5 to 18 carbon atoms, and may be replaced with an alkoxy group having 5 to 18 carbon atoms. Specific examples of these compounds of the general formula (III) include the following general formulas (VII) to (X)
IX) and the like.

[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048]

Embedded image Among the anionic surfactants represented by the general formula (III), R ₁ is a C ₅ -C ₁₈ alkyl group,
₂ is a hydrogen atom, and R ₃ and R ₄ are each —SO ₃ N
Ammonium alkyl diphenyl ether disulfonate in which H ₄ is R ₅ and R ₅ is a hydrogen atom is preferred, and those represented by formula (XII) are particularly preferred. These anionic surfactants may be used alone,
Alternatively, two or more kinds may be used in combination.

As described above, the composition contains the water-soluble film-forming component and the fluorinated surfactant, and further contains the compound represented by the general formula (II)
By adding the anionic surfactant represented by the formula (I) to form a coating solution for a resist, the uniformity of the coating of the anti-interference film can be more effectively prevented and the coating unevenness can be eliminated. Can be obtained.

The second resist coating solution of the present invention comprises:
Usually used in the form of an aqueous solution, the content of the water-soluble film-forming component is preferably 0.5 to 10.0% by weight, and the content of the fluorine-based surfactant is 1.0 to 15.0% by weight. Is preferably within the range. The amount of the anionic surfactant represented by the general formula (III) is 500 to 10000 ppm, preferably 1000 ppm, based on the resist coating solution in which the water-soluble film-forming component and the fluorine-based surfactant are dissolved.
〜5000 ppm.

The third resist coating solution of the present invention is obtained by adding the above-mentioned second coating solution to the general formula (VI)

[0052]

Embedded image (In the formula, R ₁₀ represents an alkyl group having 6 to 20 carbon atoms.) N-alkyl-2-pyrrolidone represented by the formula is blended, whereby the coatability is further improved, and even to the substrate edge. It is preferable because a coating film can be obtained with a small coating amount.

Specific examples of the compound represented by the general formula (VI) include N-hexyl-2-pyrrolidone, N-heptyl-2-pyrrolidone, N-octyl-2-pyrrolidone, N-nonyl-2-pyrrolidone. Pyrrolidone, N-decyl-2-pyrrolidone, N-undecyl-2-pyrrolidone, N-dodecyl-2-pyrrolidone, N-tridecyl-2-pyrrolidone, N-tetradecyl-2-pyrrolidone, N-pentadecyl-2-pyrrolidone, N-hexadecyl-2-pyrrolidone, N-heptadecyl-2-pyrrolidone, N-octadecyl-2-pyrrolidone and the like can be mentioned. Among these, N-octyl-2-pyrrolidone and N-dodecyl-2-pyrrolidone are referred to as “SURFADONE LP10”, respectively.
0 "and" SURFADONE LP300 "are commercially available from ASP Japan Co., Ltd., and can be easily obtained and are preferable.

The addition amount of these compounds is 100 to the coating solution in which the water-soluble film-forming component and the fluorinated surfactant are dissolved.
-10,000 ppm, preferably 150-5000 pp
m.

The second and third resist coating solutions of the present invention are usually used in the form of an aqueous solution as described above.
When an alcohol-based organic solvent such as isopropyl alcohol is contained, the solubility of the fluorine-based surfactant is improved and the uniformity of the coating film is improved. Therefore, an alcohol-based organic solvent may be added as necessary. In this case, the addition amount of the alcohol-based organic solvent is preferably selected within a range of up to 20% by weight based on the total amount of the coating solution. Further, in the resist coating solution of the present invention,
Various additives for improving the properties of the coating film may be added as desired within a range that does not impair the purpose of the present invention.

The resist material of the present invention comprises the first and second resists.
And a two-layer structure in which an interference prevention film made of any one of the third resist coating liquid is formed on the surface of the photoresist film. The photoresist used for the resist material is not particularly limited, and can be arbitrarily selected from commonly used photoresists,
Any negative type can be used arbitrarily. In particular, a negative type which is composed of a photosensitive substance and a film-forming substance and which can be developed with an alkaline aqueous solution is preferably used.

Particularly advantageous resists are positive-acting and negative-acting photoresists having the required characteristics that can be adequately adapted to recent microfabrication. Examples of the positive photoresist include a photoresist comprising a composition containing a quinonediazide-based photosensitive substance and a film-forming substance.

Examples of the quinone azide-based photosensitive material include quinone azide group-containing compounds such as sulfonic acids of quinonediazides such as orthobenzoquinonediazide, orthonaphthoquinonediazide and orthoanthraquinonediazide;
Partial or complete esterification, or partial or complete amidation of a compound having a phenolic hydroxyl group or an amino group may be mentioned. Here, as the compound having a phenolic hydroxyl group or an amino group,
For example, 2,3,4-trihydroxybenzophenone,
2,3,4,4′-tetrahydroxybenzophenone,
Polyhydroxybenzophenones such as 2,2 ', 4,4'-tetrahydroxybenzophenone, aryl gallate, phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether; Pyrogallol-1,3-dimethyl ether, gallic acid, gallic acid esterified or etherified leaving a part of the hydroxyl group, aniline, p-aminodiphenylamine and the like. Particularly preferred quinonediazide group-containing compounds are the above-mentioned polyhydroxybenzophenone and naphthoquinone-1,2-diazido-5-
A completely esterified product or a partially esterified product with sulfonyl chloride or naphthoquinone-1,2-diazide-4-sulfonyl chloride is preferred.

Examples of the film-forming substance include novolak resins obtained from phenols, cresols, xylenols and the like and aldehydes, acrylic resins, copolymers of styrene and acrylic acid, polymers of hydroxystyrene, polyvinylhydroxy Alkali-soluble resins such as benzoate and polyvinylhydroxybenzal are effective. Particularly preferred positive photoresists are those using novolak resins synthesized from aldehydes and cresols or xylenols alone or as a film-forming substance, and having a weight-average molecular weight of 2000 to 20,000 obtained by cutting the low molecular weight region. Preferably 5000 to
A range of 15,000 is preferred. In this positive photoresist, the photosensitive substance is converted to a film-forming substance 1
10 to 40 parts by weight, preferably 15 to 100 parts by weight
Those blended in the range of 30 to 30 parts by weight are suitably used.

Other positive resists include chemically amplified resists whose alkali solubility increases due to the catalytic action of an acid generated by exposure.

The negative photoresist is not particularly limited, and any known negative photoresist can be used. However, a crosslinking agent, an acid generator and a base used as a negative resist for forming fine patterns can be used. Particularly preferred is a chemically amplified negative resist containing three components of a polymer.

Next, an example of a method for preparing and using the resist material of the present invention will be described. First, after a photoresist film is formed on a substrate such as a silicon wafer, the resist coating solution of the present invention is applied on the photoresist film by a spinner method, and then subjected to heat treatment to form an interference prevention film on the photoresist film, A two-layer resist material of the present invention is prepared. Note that heat treatment is not necessarily required, and when a good coating film having excellent uniformity can be obtained only by coating, heating is not necessary.

Then, the photoresist film is selectively irradiated with actinic rays such as ultraviolet rays and far ultraviolet rays (including excimer laser) through an anti-interference film using an exposure device, and then developed, and the silicon wafer is developed. A resist pattern is formed.

The anti-interference film has an optimum film thickness for effectively reducing the interference effect of actinic rays, and this optimum film thickness is λ / 4n (where λ is the wavelength of the actinic ray to be used,
n is an odd number multiple of the refractive index of the anti-interference film). For example, in the case of an interference prevention film having a refractive index of 1.41, ultraviolet rays (g
The optimum film thickness for the actinic ray is an odd multiple of 77 nm for X-ray, an odd multiple of 65 nm for ultraviolet (i-line), and an odd multiple of 44 nm for far ultraviolet (excimer laser). ± 5n of each optimum film thickness
It is preferably in the range of m.

Further, it is preferable to form the anti-interference film on a chemically amplified negative or positive resist because it has the effect of improving the resist pattern shape in addition to the effect of preventing interference. Usually, a chemically amplified resist is N-methyl-2-pyrrolidone present in the air of a semiconductor manufacturing line,
Under the action of organic alkali vapors such as ammonia, pyridine, and triethylamine, the surface of the resist film becomes acid deficient.In the case of a negative resist, the top of the resist pattern tends to be rounded, and in the case of a positive resist, The resist pattern may be connected like an eaves. The effect of improving the shape of the resist pattern is to eliminate such a phenomenon and obtain a rectangular pattern shape. As described above, the anti-interference film of the present invention can be suitably used as a protective film material for a chemically amplified resist.

The anti-interference film may be removed at the same time as the development of the photoresist film. However, in order to completely remove the anti-interference film, it is preferable to remove the interference prevention film before the development. This peeling treatment can be performed, for example, by rotating the silicon wafer with a spinner and applying a solvent for dissolving and removing the interference prevention film to completely remove only the interference prevention film. As a solvent for removing the interference preventing film, an aqueous solution containing a surfactant can be used.

[0067]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Example 1 THMR-, a positive photoresist containing a cresol novolak resin and a naphthoquinonediazide compound
iP3000 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied onto eight 6-inch silicon wafers at different rotation speeds by a spinner method, and the resultant was applied on a hot plate at 90 rpm.
It dried at 90 degreeC and 90 second, and obtained the silicon wafer in which the film thickness of 1.19-1.31 micrometer was formed.

On the other hand, 500 g of a 20% by weight aqueous solution of EF-101 (manufactured by Tochem Products Co., Ltd.) which is perfluorooctylsulfonic acid (C ₈ F ₁₇ SO ₃ H) and 80 g of a 20% by weight aqueous solution of monoethanolamine were added. Mixed. 25 g of the mixed solution was added to 20 g of a 10% by weight aqueous solution of polyvinylpyrrolidone, and pure water was added to the obtained aqueous solution to make the whole 200 g, thereby preparing a resist coating solution. The pH of the resist coating solution was 7.0.

Next, a resist coating solution was applied on the photoresist film formed on the eight silicon wafers and dried at 90 ° C. for 90 seconds to form an anti-interference film having a thickness of about 65 nm. Then, after irradiating with an i-line through a mask pattern using a reduction projection exposure apparatus NSR-1755i7A (manufactured by Nikon Corporation), baking treatment was performed at 110 ° C. for 90 seconds on a hot plate, and 2. 3
8% by weight tetramethylammonium hydroxide (TM
AH) Paddle development with an aqueous solution at 23 ° C. for 65 seconds, followed by washing with pure water for 30 seconds to form a photoresist pattern.

The relationship between the 0.45 μm line pattern dimension and the photoresist film thickness formed on the eight silicon wafers at the same exposure dose is shown on the vertical axis with the dimensional fluctuation of the 0.45 μm line pattern and the horizontal axis. A graph as shown in FIG. 1 was obtained by plotting the photoresist film thickness on the axis. In the graph, the maximum value of the dimensional change is 0.035 μm.
Met.

Comparative Example 1 Perfluorooctylsulfonic acid (C ₈ F ₁₇ SO ₃ H)
When 17 g of a 20% by weight aqueous solution of ammonia was mixed with 500 g of a 20% by weight aqueous solution of EF-101 (manufactured by Tochem Products Co., Ltd.), the formed salt precipitated and a resist coating solution could not be prepared. Was. The pH of this solution was 6.8.

Comparative Example 2 Perfluorooctylsulfonic acid (C ₈ F ₁₇ SO ₃ H)
When 90 g of a 20% by weight aqueous solution of TMAH was mixed with 500 g of a 20% by weight aqueous solution of EF-101 (manufactured by Tochem Products Co., Ltd.), the formed salt gelled and a resist coating solution could not be prepared. Was. The pH of this solution was 6.5.

Example 2 THMR-, a positive photoresist containing a cresol novolak resin and a naphthoquinonediazide compound
iP3000 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied onto eight 6-inch silicon wafers at different rotation speeds by a spinner method, and then applied on a hot plate at 90 ° C. and 9 ° C.
After drying for 0 second, a silicon wafer on which a photoresist film having a film thickness of 1.19 to 1.31 μm was formed was obtained.

On the other hand, 500 g of a 20% by weight aqueous solution of EF-101 (manufactured by Tochem Products Co., Ltd.) which is perfluorooctylsulfonic acid (C ₈ F ₁₇ SO ₃ H) and 80 g of a 20% by weight aqueous solution of monoethanolamine were added. Mixed. 25 g of the mixed solution was added to 20 g of a 10% by weight aqueous solution of polyvinylpyrrolidone, and pure water was added to the obtained aqueous solution to make the whole 200 g. This aqueous solution has the following general formula (XII)

[0076]

Embedded image Pionin A-, an anionic surfactant represented by the formula:
43N (manufactured by Takemoto Yushi Co., Ltd.) was added at 1000 ppm to prepare a resist coating solution. The pH of the resist coating solution was 6.8.

Next, a resist coating solution was applied on the photoresist film formed on the eight silicon wafers and dried at 90 ° C. for 90 seconds to form an anti-interference film having a thickness of about 65 nm. Then, after irradiating with an i-line through a mask pattern using a reduction projection exposure apparatus NSR-1755i7A (manufactured by Nikon Corporation), baking treatment was performed at 110 ° C. for 90 seconds on a hot plate, and 2. 3
After paddle development with an 8% by weight aqueous solution of TMAH at 23 ° C. for 65 seconds, the substrate was washed with pure water for 30 seconds to form a photoresist pattern.

The relationship between the 0.45 μm line pattern dimension and the photoresist film thickness formed on the eight silicon wafers at the same exposure dose is shown on the vertical axis, with the dimensional fluctuation of the 0.45 μm line pattern and the horizontal axis. The graph shown in FIG. 2 was obtained by plotting the photoresist film thickness on the axis. In the graph, the maximum value of the dimensional change is 0.035 μm.
Met.

When the surface of the anti-interference film formed on the photoresist film was observed with a microscope, no coating unevenness was observed. Further, when the resist pattern obtained by the above treatment was observed by SEM (scanning electron microscope) photograph, a favorable resist pattern faithful to the mask pattern was formed.

Comparative Example 3 In Example 2, except that pionin A-43N (manufactured by Takemoto Yushi Co., Ltd.), which is an anionic surfactant, was omitted.
A resist coating solution was prepared in exactly the same manner. Other operations were the same as in Example 2, and
When the relationship between the line pattern dimension of m and the photoresist film thickness was examined, the relationship of FIG. 2 similar to that of Example 2 was obtained.
The maximum value of the dimensional variation was also about 0.035 μm.

However, when the surface of the anti-interference film formed on the photoresist film was observed with a microscope,
Application unevenness was observed. Furthermore, when the resist pattern obtained by the above treatment was observed by SEM (scanning electron microscope) photograph, it was found that an insect-eating pattern was formed.

Example 3 THMR which is a positive type photoresist containing a cresol novolak resin and a naphthoquinonediazide compound
-IP3300 (manufactured by Tokyo Ohka Kogyo Co., Ltd.)
Spinning method was applied on inch silicon wafers at different rotation speeds, and 90 ° C on a hot plate.
After drying for 90 seconds, a silicon wafer on which a photoresist film having a thickness of 0.96 to 1.09 μm was formed was obtained.

On the other hand, 500 g of a 20% by weight aqueous solution of EF-101 (manufactured by Tochem Products), which is perfluorooctylsulfonic acid (C ₈ H ₁₇ SO ₃ H), and 80 g of a 20% by weight aqueous solution of monoethanolamine were mixed. . 30 g of the mixed solution was added to 10 g of a 20% by weight aqueous solution of polyvinylpyrrolidone, and pure water was added to the obtained aqueous solution to make the whole 200 g. This aqueous solution has the above general formula (XI)
800 ppm of pionin A-43N (manufactured by Takemoto Yushi Co., Ltd.), which is an anionic surfactant represented by I), is represented by the following chemical formula (XX)

[0084]

Embedded image "SU" which is N-octyl-2-pyrrolidone represented by
RFADONE LP100 "(produced by ISP Japan) was added at 500 ppm to prepare a resist coating solution. The resist coating solution had a pH of 6.7.

Next, a resist coating solution was applied on the photoresist film formed on the 12 silicon wafers to form a 65 nm-thick interference preventing film. Thereafter, through a mask pattern, the reduced projection exposure apparatus NSR
Using -1755i10D (manufactured by Nikon Corporation), i
After irradiating with X-rays, baking treatment was performed on a hot plate at 110 ° C. for 90 seconds, and paddle development was performed with a 2.38 wt% TMAH aqueous solution at 23 ° C. for 65 seconds, followed by pure water for 3 seconds.
After washing for 0 second, a photoresist pattern was formed.

The relationship between the 0.45 μm line pattern size and the photoresist film thickness formed on the 12 silicon wafers at the same exposure dose is shown on the vertical axis with the dimensional fluctuation of the 0.45 μm line pattern and the horizontal axis. The film thickness of the photoresist was plotted in FIG. 3 to obtain a graph as shown in FIG. In the same graph, the maximum value of the dimensional change is 0.027μ.
m.

When the surface of the anti-interference film formed on the photoresist film was observed with a microscope, no coating unevenness was observed. Further, when the photoresist pattern obtained by the above treatment was observed by SEM (scanning electron microscope) photograph, a favorable pattern faithful to the mask pattern was formed.

FIG. 4 shows a sample obtained in the same manner as in Example 3 except that the resist coating solution of the present invention was not used, that is, the anti-interference film was not formed. 4 is a graph showing a relationship between a .45 μm line pattern dimension and a photoresist film thickness. The vertical axis is 0.45μ
The line pattern dimension fluctuation of m, and the horizontal axis is the photoresist film thickness. In the graph, the maximum value of the dimensional change is 0.071 μ
m.

[0089]

As described above in detail, according to the present invention, it is possible to provide a resist coating solution capable of preventing corrosion of equipment such as a coating device. In addition, it is possible to provide a coating liquid for a resist in which the uniformity of the coating of the anti-interference film can be achieved, the anti-interference film without coating unevenness can be formed, and a resist pattern according to the mask pattern can be obtained. Further, a photoresist material having a two-layer structure using these resist coating solutions can be provided. The anti-interference film of the resist material of the present invention is excellent in the effect of reducing the interference effect in photolithography technology, and as a result, a resist pattern having excellent pattern dimensional accuracy can be formed. In particular, it is possible to sufficiently cope with miniaturization of processing dimensions in the field of semiconductor device manufacturing in recent years, and it is possible to prevent a decrease in dimensional accuracy even in the formation of a fine pattern which has not been able to obtain a sufficient effect with the conventional antireflection film.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a photoresist film thickness and a dimensional variation of a line pattern in Example 1.

FIG. 2 is a graph showing a relationship between a photoresist film thickness and a dimensional variation of a line pattern in Example 2.

FIG. 3 is a graph showing a relationship between a photoresist film thickness and a dimensional variation of a line pattern in Example 3.

FIG. 4 is a graph showing the relationship between the photoresist film thickness and the line pattern dimensional variation when the resist coating solution of the present invention was not used, that is, when the anti-interference film was not formed in Example 3. .

Continuation of the front page (56) References JP-A-5-188598 (JP, A) JP-A-6-51523 (JP, A) JP-A-4-249257 (JP, A) JP-A-59-137943 (JP) , A) JP-A-7-181685 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/004 G03F 7/11 501 G03F 7/26 511

Claims (6)

(57) [Claims] 1. A resist coating solution containing a water-soluble film-forming component and a fluorine-based surfactant, wherein the fluorine-based surfactant is represented by the general formula (I): (Wherein, Rf is a fluorinated hydrocarbon group in which some or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms) A salt with an alkanolamine, and a compound of the general formula (I
I) (In the formula, R′f is a fluorinated hydrocarbon group in which some or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms.) A resist coating liquid, which is at least one selected from salts of compounds and alkanolamines. 2. The resist coating solution according to claim 1, wherein the fluorinated surfactant is a salt of perfluorooctylsulfonic acid and alkanolamine. 3. A resist coating solution containing a water-soluble film-forming component and a fluorine-based surfactant, further comprising a compound represented by the general formula (III): (Wherein at least one of R ₁ and R ₂ has 5 to 18 carbon atoms)
Is an alkyl or alkoxy group, the remainder being a hydrogen atom,
An alkyl group or an alkoxy group having 5 to 18 carbon atoms; at least one of R ₃ , R ₄ and R ₅ is an ammonium sulfonate group or a sulfonate-substituted ammonium group, and the remainder is a hydrogen atom, an ammonium sulfonate group or a sulfonate; A coating solution for resists, wherein at least one selected from anionic surfactants represented by the formula: 4. A resist coating solution containing a water-soluble film-forming component and a fluorine-containing surfactant, further comprising a compound represented by the general formula (III): (Wherein at least one of R ₁ and R ₂ has 5 to 18 carbon atoms)
Is an alkyl or alkoxy group, the remainder being a hydrogen atom,
An alkyl group or an alkoxy group having 5 to 18 carbon atoms; at least one of R ₃ , R ₄ and R ₅ is an ammonium sulfonate group or a sulfonate-substituted ammonium group, and the remainder is a hydrogen atom, an ammonium sulfonate group or a sulfonate; At least one selected from anionic surfactants represented by the formula:
The following general formula (VI) (Wherein R ₁₀ represents an alkyl group having 6 to 20 carbon atoms). A resist coating solution comprising N-alkyl-2-pyrrolidone represented by the formula: 5. The fluorosurfactant represented by the general formula (I): (Wherein, Rf is a fluorinated hydrocarbon group in which some or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms) A salt with an alkanolamine, and a compound of the general formula (I
I) (In the formula, R′f is a fluorinated hydrocarbon group in which some or all of the hydrogen atoms of a saturated or unsaturated hydrocarbon group having 2 to 20 carbon atoms are replaced with fluorine atoms.) The resist coating liquid according to claim 3, wherein the coating liquid is at least one selected from salts of a compound and an alkanolamine. 6. A resist material comprising an anti-interference film comprising the resist coating solution according to claim 1 formed on a photoresist film surface.