JPH1172925A - Undercoat layer composition and pattern forming method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the undercoat layer composition capable of forming a pattern having a perpendicular side wall and a good rectangular section by incorporating a compound having a substituent to be decomposed by an acid and to produce an alkali-soluble group after the decomposition, and an acid generator. SOLUTION: The undercoat layer composition contains the compound having the subtituent to be decomposed by an acid and to produce an alkali-soluble group after the decomposition, and an acid generator. It is preferred that this compound has a structure represented by the formula in which each of R<1> and R<2> is an H atom or a methyl group; R<3> is a protective group to be decomposed by an acid and converted into the alkali-soluble group; R<4> is an optionally substituted polycyclic aromatic hydrocarbon group; and each of (j) and (k) is a positive integer. An acid is produced from the acid generator by exposure and the compound is decomposed and the alkali-soluble group is formed, and the exposed parts of the undercoat layer are made soluble in an alkaline solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for manufacturing a semiconductor device and a method for manufacturing a semiconductor device, and more particularly to a composition for an underlayer film used for forming a pattern on a wafer substrate, and a method for using the same. A pattern forming method.

[0002]

2. Description of the Related Art A method for manufacturing a semiconductor device includes many steps of depositing several layers of a plurality of substances on a silicon wafer and patterning the layers into a desired pattern. This patterning step is performed by the following method. That is, first, an insulator on a silicon wafer,
A work such as a conductor or a semiconductor thin film is formed on a work, and a resist is applied on the work by a spin coating method or the like to form a resist film. Next, after selectively exposing the resist film, the exposed resist film is developed to form a resist pattern. Further, an insulator, a conductor, and a semiconductor thin film, which are workpieces formed on the substrate, are etched using the resist pattern as an etching mask, and fine wirings, openings, and the like are processed into a desired pattern. In this step, it is important to control the resist pattern dimension with high accuracy. However, when the reflectance of the substrate to the exposure light is high,
A standing wave of exposure light is generated in the resist film, and a slight variation in the resist film thickness affects the pattern size. Therefore, there is a problem that a resist pattern cannot be formed with high dimensional accuracy.

As a means for solving this problem, by forming a lower layer film such as an anti-reflection film for preventing reflection of exposure light from the work, the light returning from the work to the resist film is formed. (Japanese Patent Application Laid-Open No. 58-91635). As described above, by forming the antireflection film between the resist film and the workpiece, the exposure light passing through the resist film causes multiple reflection in the antireflection film and is attenuated. Alternatively, the exposure light that has passed through the resist film is absorbed by the anti-reflection film, thereby suppressing the reflection of the exposure light from the interface below the resist film.
As a result, the standing wave generated in the resist film is weakened, and the dimensional controllability of the resist pattern is improved.

As an antireflection film, a resin film disclosed in Japanese Patent Application Laid-Open No. Sho 59-14945 or the like is mainly used because it can be formed by a spin coating method having a low process cost. When a resin film is used as an anti-reflection film,
The following materials and methods are used as materials and processing methods for the antireflection film.

1) A method of forming an antireflection film using a plasma decomposition type resin and etching the antireflection film using a resist pattern as an etching mask. 2) An antireflection film using a resin soluble in an alkali developing solution. A latent image is formed on the resist film and the anti-reflection film by pattern exposure, and these latent images are simultaneously dissolved and removed at the time of development processing. 3) A photosensitive composition having absorptivity to exposure light is used. Forming a latent image on the anti-reflection film by performing pattern exposure on the anti-reflection film, and dissolving and removing the latent image during development processing; 4) polymethyl methacrylate, polysulfone, etc. An anti-reflection film is formed using a photosensitive resin of the PCM method (P
replaceable Maski Maski
ng) Method of Developing Antireflection Film However, each of the above-mentioned conventional methods has some problems. For example, in the method 1), FIG.
Although the anti-reflection film can be processed in a vertical shape as shown in FIG. 3A, the etching selectivity cannot be obtained because the resin film 42 constituting the anti-reflection film is made of the same organic material as the resist film 43. The problem arises. Therefore, when the antireflection film 42 is etched, the resist film 43 having a thickness equal to or greater than the thickness of the antireflection film is removed. This makes it impossible to secure the thickness of the resist film required for etching the film to be processed. In recent years, the limit of the photolithography has been approached, and the problem becomes more remarkable when the thickness of the resist film is reduced in order to increase the resolution.

In the method 2), a predetermined region of the antireflection film is not removed by dry etching, so that the resist film can be prevented from being thinned. However, when the antireflection film 42 is dissolved and removed with a developing solution, the development proceeds isotropically, so that the shape after the development processing becomes a biting shape as shown in FIG. Therefore, there arises a problem that an antireflection film pattern having a desired width cannot be obtained.

In the method 3), since the exposure light is absorbed by the antireflection film, the photosensitive reaction at the bottom of the antireflection film 42 does not sufficiently proceed. For this reason, after the development processing, FIG.
As shown in (c), the remaining 44 is left. 4)
In the method (1), when the conventional material is used, the resolution is low, and it is difficult to resolve a pattern smaller than a sub-quarter micron, and as shown in FIG.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a composition for an underlayer film having a vertical side wall and capable of forming a pattern having a good rectangular cross section.

Further, the present invention provides a method of patterning a lower layer film, which suppresses a reduction in the thickness of a resist pattern in the upper layer and reduces a pattern having vertical side walls and a rectangular cross section having a good shape with high resolution. It is another object of the present invention to provide a method for forming a semiconductor device with high dimensional accuracy.

[0010]

In order to solve the above-mentioned problems, the present invention (claim 1) provides a compound having a substituent capable of being decomposed by an acid and generating an alkali-soluble group after decomposition, and a method for producing the acid. Provided is a composition for an underlayer film containing an acid generator.

The present invention (claim 2) provides a composition for an underlayer film, comprising a compound having a substituent cross-linkable by an acid, and an acid generator that generates the acid.

The present invention (claim 3) is a composition comprising a compound having a substituent capable of decomposing by an acid and generating an alkali-soluble group after decomposition, and an acid generator generating the acid, The composition provides a composition for an underlayer film containing a polycyclic aromatic hydrocarbon group.

Further, the present invention (claim 6) provides a step of forming an underlayer film on a film to be processed, a step of forming a resist film on the underlayer film, and a step of patternwise exposing the resist film and the underlayer film. And a step of developing a predetermined area of the resist film and the lower layer film after the exposure with a developing solution, wherein the lower layer film has a property that the solubility in the developing solution changes by the action of an acid. And a pattern forming method, wherein at least one of the resist film and the lower layer film contains the acid-generating compound.

The present invention (claim 9) further comprises a step of forming a lower layer film on the film to be processed, a step of forming a resist film containing a phenolic resin on the lower layer film, Pattern exposing using a first light, developing the exposed resist film to form a resist pattern, and irradiating the lower film with a second light using the resist pattern as a mask And a step of developing the exposed portion of the underlayer film, wherein the underlayer film has a substituent capable of decomposing by an acid and generates an alkali-soluble group after decomposition, and an acid generating the acid. A pattern forming method is provided which is formed from a composition for an underlayer film containing a generator and wherein the composition for an underlayer film contains a polycyclic aromatic hydrocarbon group.

Further, the present invention (Claim 12) provides an underlayer film containing a compound having a substituent capable of decomposing by an acid to generate an alkali-soluble group after decomposition, and an acid generator generating the acid. Forming a resist film containing a phenolic resin on the lower film, pattern-exposing the resist film using a charged beam, and developing the exposed resist film. A step of forming a resist pattern by irradiating the lower layer film with light using the resist pattern as a mask; and a step of developing an exposed portion of the lower layer film. .

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The first composition for an underlayer film of the present invention is a composition containing a compound having a substituent that is decomposed by an acid and an acid generator that generates the acid. The underlayer film formed using the composition for an underlayer film of the present invention can be used as an underlayer film of a resist such as an antireflection film. In this case, a positive resist can be generally used as the resist.

The first composition of the present invention contains a compound having a substituent which is decomposed by an acid and which generates an alkali-soluble group after decomposition. When a lower layer film is formed using the present composition in the manufacture of a semiconductor device, a resist film is formed on the lower layer film. When a positive resist is used as the resist, an acid is generated from the acid generator in the underlayer film by exposure to light, and the acid is diffused to decompose the compound contained in the underlayer film to form an alkali-soluble group. Is generated.
Thus, the exposed portion of the lower layer film is easily dissolved in the alkaline aqueous solution.

Compounds having a substituent which can be decomposed by an acid and which produce an alkali-soluble group after decomposition, which can be used in the present invention, act as a dissolution inhibitor. As dissolution inhibitors,
Compounds having the following properties can be used. That is, the compound has a function of inhibiting dissolution of the alkali-soluble resin in an unexposed state. Further, the compound has a substituent that decomposes in the presence of an acid, and the product after decomposition generates —O, —COO, or —SO ₃ by the action of an alkaline solution. Such dissolution inhibitors include, for example, U.S. Pat. Nos. 4,491,628 and 4,603,101;
A compound described in JP-A-63-27829 or a compound having a carboxylic acid group or a phenolic hydroxyl group in the skeleton, wherein part or all of the hydroxy terminal is substituted with an acid-decomposable protecting group. Compounds. Examples of this protecting group include t-butyl ester, t-butoxycarbonyl, tetrahydropyranyl,
Examples include a silyl group and an alicyclic group. Specific examples of such compounds are listed below.

[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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In these chemical formulas, m, n, p and q indicate the degree of polymerization or the composition (polymerization ratio) of the copolymer. m, n, p and q are positive integers.

In the first composition of the present invention, the compounding amount of the dissolution inhibitor is preferably from about 10 parts by weight to about 99.999 parts by weight based on 100 parts by weight of the solids in the underlayer film composition. preferable. If the amount is less than 10 parts by weight, it becomes difficult to obtain a contrast between the exposed part and the unexposed part, and it becomes difficult to form a fine pattern of sub-quarter microns or less. On the other hand, if it exceeds 99.999 parts by weight, the ratio of the acid generator contained in the lower layer film may be too low, and the dissolution inhibitor may be difficult to be alkali-soluble.

In the present invention, the wavelength range of 240 to
When exposure is performed using a light source of 450 nm, it is preferable to use a dissolution inhibitor having a polycyclic aromatic hydrocarbon group bonded to a side chain. The polycyclic aromatic hydrocarbon group in the present invention may be substituted or unsubstituted with two or more rings.
The reason for this is that the polycyclic aromatic hydrocarbon group has high absorbency for exposure light and suppresses the reflection of the exposure light on the resist film. Specific examples of these dissolution inhibitors are shown below.

[0033]

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Further, as the dissolution inhibitor, a compound having a structure represented by the following general formula (1) is most preferable.

[0035]

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The above formula (1), R ¹ and R ² may be the same or different, a hydrogen atom or a methyl group respectively; protecting group comprising an alkali-soluble group by decomposing by the R ³ acid; R ⁴ is It is a substituted or unsubstituted polycyclic aromatic hydrocarbon group, and j and k are positive integers.

Incidentally, R ³ in the general formula (1) includes, for example, t-butyl ester, t-butoxycarbonyl, tetrahydropyranyl, silyl group, alicyclic group and the like. More specifically, the following groups may be mentioned.

[0038]

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Assuming that the ratio (j / (j + k)) of the protecting group R ^{3 in} the general formula (1) is X, X is 0.0
It is preferable that 5 <X <0.95. X is 0.05
In the following cases, the solubility in the alkaline developer is too high. On the other hand, if it exceeds 0.95, it becomes difficult to dissolve in an alkali developing solution. As a result, when the resist pattern becomes fine, the resolution of the lower layer film may be reduced.

Hereinafter, examples of the compound having the structure represented by the general formula (1) will be shown.

[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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The acid generator which can be added to the first composition of the present invention is not particularly limited as long as it generates an acid at the time of pattern exposure and makes the dissolution inhibiting group alkali-soluble. The following compounds are exemplified. Phenylmethylsulfone, ethylphenylsulfone, phenylpropylsulfone, methylbenzylsulfone, benzylsulfone, dibenzylsulfone, methylsulfone, ethylsulfone, butylsulfone, methylethylsulfone, methylsulfonylacetonitrile, phenylsulfonylacetonitrile, toluenesulfonylacetonitrile, benzylphenyl Sulfone, nitrophenylsulfonylacetonitrile, fluorophenylsulfonylacetonitrile, chlorophenylsulfonylacetonitrile, methoxyphenylsulfonylacetonitrile, α-methylphenylsulfonylacetonitrile, ethylsulfonylacetonitrile, methylthiomethyl-p-toluylsulfone, phenylsulfene Nylacetophenone, phenylsulfonylpropionitrile, phenylsulfonylpropionic acid and its ester compound, bromomethyl-2- (phenylsulfonylmethyl) benzene, naphthylmethylsulfone, 1-methyl-2-((phenylsulfonyl) methyl) benzene, trimethyl- 3-
(Phenylsulfonyl) orthopropionate, bis (phenylsulfonyl) methane, bis (methylsulfonyl) methane, bis (ethylsulfonyl) methane,
(Methylsulfonyl) (phenylsulfonyl) methane, phenylsulfonylacetophenone, methylsulfonylacetophenone, tris (phenylsulfonyl) methane, phenylthio-bis (phenylsulfonyl) -methane, phenylmercapto-bis (methylsulfonyl) -methane, tris (methylsulfonyl) ) Methane, tris (ethylsulfonyl) methane, bis (phenylsulfonyl) -methylsulfonyl-methane,
Bis (methylsulfonyl) -phenylsulfonyl-
Methane, phenylsulfonyl-ethylsulfonyl-
Methylsulfonyl-methane, tris (4-nitrophenylsulfonyl) methane, tris (2,4-nitrophenylsulfonyl) methane, bis (phenylsulfonyl)-(4-nitrophenylsulfonyl) -methane, bis (phenylsulfonyl)-( 3-nitrophenylsulfonyl) -methane, bis (phenylsulfonyl)-(3-nitrophenylsulfonyl) -methane, bis (phenylsulfonyl)-(2-nitrophenylsulfonyl) -methane, bis (methylsulfonyl)-(4- Fluorophenylsulfonyl) -methane,
Bis (phenylsulfonyl)-(4-chlorophenylsulfonyl) -methane, bis (phenylsulfonyl)-(4-fluorophenylsulfonyl) -methane,
1,1,1-tris (phenylsulfonyl) ethane and the like can be mentioned.

Further, it is also possible to use a compound represented by the following chemical formula.

[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062]

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[0063]

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The compounding amount of these acid generators is preferably 0.001 to 40 parts by weight based on 100 parts by weight of the solids in the underlayer film composition. If the amount is less than 0.001 part by weight, the dissolution inhibitor in the lower layer film is not sufficiently decomposed,
Resolution may be reduced. On the other hand, if it exceeds 40 parts by weight, the coating characteristics of the lower layer film tend to deteriorate.

The first composition of the present invention may contain an alkali-soluble resin in addition to the components described above.
As the alkali-soluble resin, a dissolution rate of 0.1 to 500 nm / in an alkali developing solution (eg, an aqueous solution of 2.38% by weight of tetramethylammonium hydroxide) is used.
Those in the range of sec are preferable.

Generally, a phenolic resin can be used as the alkali-soluble resin. As the phenolic resin, for example, phenol novolak resin, cresol novolak resin, xylenol novolak resin,
Vinylphenol resin, isopropynylphenol resin; copolymer of vinylphenol with acrylic acid, methacrylic acid derivative, acrylonitrile, or styrene derivative; isopropenylphenol with acrylic acid, methacrylic acid derivative, acrylonitrile, or styrene derivative And a copolymer of More specifically,
Poly (p-vinylphenol), a copolymer of p-isopropenylphenol and acrylonitrile, a copolymer of p-isopropenylphenol and styrene, a copolymer of p-vinylphenol and methyl methacrylate, p
-Copolymers of vinylphenol and styrene.

Further, a silicon-containing alkali-soluble polymer such as a polysiloxane having a phenol in a side chain, a polysilane; or a novolak resin synthesized from a phenol having a silicon in a side chain can be used.

In addition to these polymers, there may be mentioned those similar to the alkali-soluble resins described above. As a specific example, a novolak resin obtained by polycondensing a phenol derivative under acidic conditions using formaldehyde,
Xylenol, ethylphenol, butylphenol,
Polymers containing a halogenated phenol, naphthol, or the like in the skeleton can be mentioned. Also, melamine-formaldehyde resin, poly 4-hydroxymaleimide, copolymer of vinylphenol and acrylic acid, copolymer of vinylphenol and methacrylic acid, copolymer of vinyl compound and polyacrylic acid, vinyl Examples include a copolymer of a compound and methacrylic acid, and a polyimide precursor (polyamic acid).

In the present invention, the wavelength range of 240 to 45
When exposure is performed using a light source of 0 nm, it is preferable to use an alkali-soluble resin having a polycyclic aromatic hydrocarbon group bonded to a main chain or a side chain. The reason is that the polycyclic aromatic hydrocarbon group has a high absorbency to the exposure light, and suppresses the reflection of the exposure light to the resist without fail. Specific examples of these alkali-soluble resins are shown below.

[0070]

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[0071]

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[0072]

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In these chemical formulas, m and n are
Indicates the degree of polymerization or the composition of the copolymer (polymerization ratio). m and n are positive integers.

These alkali-soluble resins can be used alone or in the form of a mixture of two or more.

When these alkali-soluble resins are used, the amount thereof is preferably less than 50 parts by weight based on 1 part by weight of the dissolution inhibitor. When the compounding amount of the alkali-soluble resin is 50 parts by weight or more,
The resolution of the lower layer film may be deteriorated. When the above-mentioned dissolution inhibitor is an alkali-soluble polymer compound, this dissolution inhibitor can also be used as a resin component in the composition for the underlayer film, that is, an alkali-soluble resin.

The first composition of the present invention comprises a compound having a substituent capable of being decomposed by an acid and generating an alkali-soluble group after decomposition, an acid generator and, if necessary, an alkali-soluble resin in an organic solvent. It can be prepared by filtration. Examples of such organic solvents include cyclohexanone, acetone, methyl ethyl ketone, ketone solvents such as methyl isobutyl ketone, cellosolve solvents such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, ethyl acetate, butyl acetate, isoamyl acetate, and the like. γ
Ester solvents such as -butyllactone; dimethylsulfoxide; dimethylformamide; N-methylpyrrolidone; These organic solvents may be used alone or in the form of a mixture. Further, these may contain an appropriate amount of an aliphatic alcohol such as isopropyl alcohol, xylene, toluene or the like.

The lower layer film can be formed by applying the solution material prepared as described above on a wafer substrate by a spin coating method or the like, baking and evaporating and drying the solvent.

The second composition of the present invention contains a compound having a substituent cross-linkable by an acid, and an acid generator that generates the acid. When a lower layer film is formed using the present composition in the manufacture of a semiconductor device, a resist film is formed on the lower layer film. Generally, a negative resist can be used as this resist.

Since the second composition of the present invention contains an acid generator that generates an acid upon exposure, when a predetermined region of the underlayer film is exposed, the acid in the exposed portion of the underlayer film is reduced. Acid is generated from the generator. This acid diffuses to the bottom of the lower layer film, and the acid crosslinkable compound contained in the lower layer film is cross-linked,
As a result, the exposed portion of the lower film becomes less soluble in the alkaline aqueous solution.

Examples of the acid generator include the same compounds as those described in the first composition. further,
As in the case of the first composition, the second composition can also contain an alkali-soluble resin.

Examples of the compound having a substituent cross-linkable by an acid which can be used in the second composition of the present invention include, for example,
Aminoplast resins can be used. Examples of the aminoplast resin include a melamine-formaldehyde resin, a urea-formaldehyde resin, a glycol-formaldehyde resin, and a benzoguanamine-formaldehyde resin. These can be used alone or in a mixture of two or more. As available aminoplast resins, for example, Cymel Beetle series (manufactured by American Cynamide) and the like are known.

In the second composition of the present invention, the compounding amount of the acid-crosslinkable compound as described above is 10 parts by weight or more and 99.99 parts by weight based on 100 parts by weight of the solid content in the underlayer film composition.
It is preferable that the content be about 9 parts by weight or less. If the amount is less than 10 parts by weight, it is difficult to pattern the lower layer film due to insufficient crosslinking and anisotropy. 99.99
If the amount exceeds 9 parts by weight, the ratio of the acid generator contained in the lower layer film is reduced, so that crosslinking is difficult to occur. As a result, it may be difficult to pattern the lower layer film with anisotropy.

When an alkali-soluble resin is blended with the second composition of the present invention, the blending amount is desirably less than 50 parts by weight based on 1 part by weight of the compound having a substituent cross-linkable by an acid. It is. If the blending amount of the alkali-soluble resin is 50 parts by weight or more, the dissolution rate of the unexposed portion is too high, and the contrast may be reduced.

The second composition is prepared by dissolving a compound having a substituent cross-linkable by an acid, an acid generator and, if necessary, an alkali-soluble resin in an organic solvent. Can be prepared in the same manner as described above.

The third composition of the present invention is a composition comprising a compound having a substituent capable of decomposing by an acid and generating an alkali-soluble group after decomposition, and an acid generator generating the acid. And a composition containing a polycyclic aromatic hydrocarbon group.

In the third composition of the present invention, as the compound having a substituent capable of being decomposed by an acid and generating an alkali-soluble group after decomposition, the compounds described in the first composition can be used. . The same compounds as described above can be used for the acid generator.

The polycyclic aromatic hydrocarbon group includes a dissolution inhibitor,
It may be contained in a component separate from the alkali-soluble resin and the acid generator. That is, the third composition can be a three-component composition further containing a compound having a polycyclic aromatic hydrocarbon group in addition to the dissolution inhibitor and the acid generator. As the compound having a polycyclic aromatic hydrocarbon group, for example, anthracene, naphthacene, naphthalene, phenanthrene, and-
_{CH 3, -CN, -COOH, -Cl} , -NO 2, -N
Substituents substituted with substituents such as H ₂ , —CHO, —COCH ₃ , and —OH, and anthraquinone dyes such as Slen Red 5GK, Slen Brown R, Slen Red Violet RPK, and Slen Brilliant Green B can be given. The content of these compounds is preferably in the range of 0.1 to 95 parts by weight based on 100 parts by weight of the solid components in the underlayer film composition. The reason is that if it is 0.1 parts by weight or less, it is not possible to obtain absorptivity to light having a wavelength of 240 to 450 nm necessary to act as an antireflection film when exposing the resist, and 95 parts by weight or more If so, the contrast is lowered when the exposed portion is selectively dissolved and removed with an alkali solution, so that a good shape cannot be obtained after development.

In the third composition of the present invention, the polycyclic aromatic hydrocarbon group is preferably contained in a form bonded to the main chain or side chain of the resin. The reason is that, after applying the resist solution on the underlayer film, when baking is performed, the compound having a polycyclic aromatic hydrocarbon group may diffuse into the resist and deteriorate the resolution of the resist. It is.

As the resin having a polycyclic aromatic hydrocarbon group, for example, the above-mentioned alkali-soluble resin (compound (p
-1) to (p-17)) and dissolution inhibitors (compounds (i-54) to (i-7) that can be incorporated in the first composition.
4)).

The third composition has a wavelength range of 240 to 450.
Since it contains a compound having a polycyclic aromatic hydrocarbon group having a high absorbance for light of nm, reflection of exposure light to a resist can be reliably suppressed. Therefore, the third composition can be particularly preferably used as an antireflection film when a resist pattern is formed using light in a wavelength range of 240 to 450 nm.

Further, the compound having a polycyclic aromatic hydrocarbon group contained in the third composition has a wavelength range of 150.
It has high transparency to light of up to 230 nm. Therefore, by performing pattern exposure of the underlayer film using light having a wavelength in this range, the bottom of the underlayer film can be exposed.

For these reasons, it is preferable to use the compound represented by the above general formula (1) as a compound having a substituent which is decomposed by an acid and which generates an alkali-soluble group after decomposition. Specifically, dissolution inhibitors (compounds (i-59) to (i-7) that can be blended in the first composition
It is desired to incorporate 4)) into the third composition.

The third composition is the same as the first composition except that a compound containing a polycyclic aromatic hydrocarbon group or a dissolution inhibitor having a polycyclic aromatic hydrocarbon group is added. It can be prepared in a similar manner.

Next, the pattern forming method of the present invention will be described.

In the first pattern forming method of the present invention, a step of forming a lower layer film on a film to be processed, a step of forming a resist film on the lower layer film, and pattern exposure of the resist film and the lower layer film And a step of developing a predetermined area of the resist film and the lower layer film after the exposure with a developing solution, wherein the lower layer film has a property that solubility in the developing solution changes by an action of an acid. Further, at least one of the resist film and the lower layer film contains the compound that generates the acid.

In the first pattern forming method of the present invention, the film to be processed may be a silicon oxide film; a silicon nitride film; a silicon oxynitride film; a spin-on-glass; Silicon-based materials such as amorphous silicon, polysilicon, and silicon substrates; wiring materials and electrode materials such as aluminum, aluminum silicide, copper, tungsten, tungsten silicide, cobalt silicide, and ruthenium; Never.

The underlayer film formed on such a film to be processed has a characteristic that the solubility in a developing solution is changed by the action of an acid. Specifically, the underlayer film is formed of a composition for an underlayer film containing a group that is decomposed by an acid or a group that is crosslinked by an acid.

As the composition for an underlayer film having a group decomposed by an acid, for example, the first composition for an underlayer film of the present invention can be used. That is, the composition contains a compound having a substituent that is decomposed by an acid and an acid generator that generates the acid. In this case, a resist film can be formed on the lower film using a positive resist composition.

The step of forming a pattern by the first method of the present invention using the first composition of the present invention and the positive resist composition will be described in detail below with reference to the drawings.

FIG. 2 is a sectional view showing an example of the steps of the first pattern forming method of the present invention.

First, as shown in FIG. 2A, a lower film 2a is formed on a film 1 to be processed formed on a substrate. The lower layer film is formed by applying the composition as described above on the film to be processed 1 by, for example, spin coating, dipping, or the like.
If necessary, it can be formed by baking at a predetermined temperature.

Next, as shown in FIG. 2B, a resist film 3a is formed on the lower film 2a. The resist composition for forming the resist film is not particularly limited as long as it is a composition that can be patterned by exposure to visible light, ultraviolet light, or the like. Examples of the positive resist composition include a resist composition (IX-770, manufactured by Nippon Synthetic Rubber Co., Ltd.) containing naphthoquinonediazide and a novolak resin, a polyvinylphenol resin protected with t-BOC, and an acid generator. Containing chemically amplified resist composition (A
A resist composition (UVIIH) containing PEX-E, manufactured by Shipley Co., Ltd.), and a polyvinylphenol resin obtained by copolymerizing tertiary butyl methacrylate and an acid generator.
S, manufactured by Shipley Co., Ltd.) and the like, but are not limited thereto.

The resist composition as described above is applied onto the lower layer film 2a by a method such as a spin coating method or a dipping method, and baked at a predetermined temperature if necessary, thereby forming a resist film 3a. .

The thus formed resist film 3a and lower film 2a are subjected to pattern exposure as shown in FIG. 2 (c). That is, the exposure light 4 is applied to the resist film 3a and the lower film 2a through a mask having a desired pattern.
Irradiation. As the exposure light 4, visible light, ultraviolet light, or the like can be preferably used. As a light source for irradiating ultraviolet light, for example, a mercury lamp, XeF (wavelength = 351 n)
m), XeCl (wavelength = 308 nm), KrF (wavelength =
248 nm), KrCl (wavelength = 222 nm), ArF
(Wavelength = 193 nm) and F ₂ (wavelength = 151n)
m) and the like. Further, pattern exposure may be performed using an electron beam, an ion beam, or X-rays.

By such pattern exposure, the lower film 2
In the exposed portion a, an acid is generated from the acid generator, and the acid reacts with a dissolution inhibitor (a compound having a substituent that can be decomposed by an acid) contained in the lower layer film.

The exposed resist film 3a and the lower film 2a
Is preferably baked. Thereby, the acid generated from the acid generator in the lower film 2a diffuses to the bottom of the lower film, and the resist film 3a and the lower film 2
A latent image 5a is formed on a.

After the latent image has been formed, the resist film 3a and the lower layer film 2a are developed with a predetermined developing solution, whereby the latent image portions of these films are dissolved and removed, as shown in FIG. A pattern is formed. The developer used here can be appropriately selected according to the resist material. For example, alkali developers such as tetramethylammonium hydroxide solution, choline, sodium hydroxide, potassium hydroxide and the like can be mentioned.

As described above, when a pattern is formed by the first method of the present invention using the first composition for an underlayer film of the present invention and the positive resist composition, the underlayer film has Since an acid generator is contained, an acid is generated in an exposed portion of the lower layer film by pattern exposure. This acid diffuses to the bottom of the lower film, and the compound contained in the lower film (dissolution inhibitor)
Is decomposed, so that the exposed portion of the lower layer film exhibits alkali solubility. As described above, in the first pattern forming method of the present invention, the solubility of the underlayer film in the aqueous alkali solution is changed by the diffusion of the acid. Therefore, the lower layer film can be dissolved and removed even at the bottom of the lower layer film where the intensity of the exposure light is attenuated. Therefore, it is possible to form a pattern having a vertical sidewall and a rectangular cross section having a good shape.

By selectively etching the film 1 to be processed by using the thus formed resist pattern and lower layer film pattern as an etching mask, the film to be processed can be finely processed with high dimensional accuracy.

As the composition for an underlayer film having a group crosslinkable by an acid, which can be used in the first pattern forming method of the present invention, for example, the composition for a second underlayer film of the present invention can be used. . That is, it is a composition containing a compound having a substituent cross-linked by an acid and an acid generator that generates the acid. In this case, a resist film can be formed on the lower layer film using a negative resist composition.

The step of forming a pattern by the first method of the present invention using the second composition of the present invention and the negative resist composition will be described below in detail with reference to the drawings.

FIG. 3 is a sectional view showing another example of the process of the first pattern forming method of the present invention.

First, as shown in FIG. 3A, a lower film 2b is formed on a film 1 to be processed formed on a substrate. The lower layer film is formed by applying the composition as described above on the film to be processed 1 by, for example, spin coating, dipping, or the like.
If necessary, it can be formed by baking at a predetermined temperature.

Next, as shown in FIG. 3B, a resist film 3b is formed on the lower film 2b. The resist composition for forming the resist film is not particularly limited as long as it is a composition that can be patterned by exposure to visible light, ultraviolet light, or the like. Examples of the negative resist composition include a chemically amplified resist (SNR200, manufactured by Shipley) containing polyvinylphenol, a melamine resin, and a photoacid generator, and a resist (RD) containing polyvinylphenol and a bisazide compound. -2000, manufactured by Hitachi Chemical Co., Ltd.), but are not limited thereto.

The resist composition as described above is applied on the lower layer film 2b by a method such as spin coating or dipping, and baked at a predetermined temperature if necessary, thereby forming the resist film 3b. .

The resist film 3b and the lower film 2b thus formed are subjected to pattern exposure as shown in FIG. That is, the exposure light 4 is applied to the resist film 3b and the lower film 2b through a mask having a desired pattern.
Irradiation. As the exposure light 4, the above-described visible light, ultraviolet light, or the like can be used. As the light source for irradiating ultraviolet light, the above-described light sources can be used. Further, pattern exposure may be performed using an electron beam, an ion beam, or X-rays.

By such pattern exposure, an acid is generated from the acid generator in the exposed portion of the lower layer film 2b, and this acid reacts with a compound having a substituent which can be crosslinked by the acid contained in the lower layer film.

Exposed resist film 3b and underlying film 2b
Is preferably baked. As a result, the acid generated from the acid generator in the lower film diffuses to the bottom of the lower film, and a latent image 5b is formed on the resist film 3b and the lower film 2b. In this case, the latent image portions formed on the resist film 3b and the lower film 2b remain without being dissolved in the developer.

After the latent image is formed, the resist film 3b and the lower layer film 2b are developed with a predetermined developing solution, whereby the latent image portions of these films are cross-linked, and portions other than the latent image are dissolved and removed. Then, a pattern as shown in FIG. 3D is formed. Here, examples of the developer used include those described above.

As described above, when a pattern is formed by the first method of the present invention using the second composition for an underlayer film of the present invention and the negative resist composition, the underlayer film has Since an acid generator is contained, an acid is generated in an exposed portion of the lower layer film by pattern exposure. This acid diffuses to the bottom of the underlayer film and crosslinks the acid-crosslinkable compound contained in the underlayer film, so that the exposed portion of the underlayer film becomes insoluble in the aqueous alkaline solution. As described above, in the first pattern forming method of the present invention, the solubility of the lower layer film in the aqueous alkaline solution is changed by the diffusion of the acid. For this reason, even at the bottom of the underlayer film where the intensity of the exposure light is attenuated, the unexposed portion of the underlayer film can be developed and removed, leaving the exposed portion of the underlayer film. Therefore, it is possible to form a pattern having a vertical sidewall and a rectangular cross section having a good shape.

By selectively etching the film to be processed 1 using the thus formed resist pattern and lower layer film pattern as an etching mask, the film to be processed can be finely processed with high dimensional accuracy.

The first pattern forming method of the present invention has been described above with reference to examples of the combination of the composition for a lower layer film and a resist material, but the method of the present invention is not limited to this. For example, a negative pattern can be formed by the first method using a combination of the first composition for an underlayer film of the present invention and a positive resist composition. In this case, a low-polarity solvent such as anisole, toluene, or xylene may be used as the developer. Polarized portions in the exposed portions of the resist film and the lower film can obtain a negative pattern that is hardly soluble in a low-polarity solvent. When such a developer is used, a negative pattern can be formed even when the second composition of the present invention and the positive resist composition are used in combination.

In the first pattern forming method of the present invention, at least one of the lower layer film and the resist film contains an acid generator. It is preferable that such an acid generator is contained in the underlayer film because the acid easily diffuses to the bottom of the underlayer film and the shape of the underlayer film pattern after development becomes good.

On the other hand, when an acid generator is contained in the resist film, it is necessary that the acid diffuses sufficiently and uniformly into the underlayer film and reacts with the dissolution inhibiting group or the acid crosslinking group. . Therefore, the amount of the acid generator in the resist is preferably at least about 0.001 part by weight or more based on 100 parts by weight of the solid content in the resist.
However, if the amount of the acid generator compounded in the resist is too large, there is a possibility that the coating properties of the resist may deteriorate. Therefore, the compounding amount is preferably less than 40 parts by weight.

When the resist film containing the acid generator is formed on the lower film, the lower film may not necessarily contain the acid generator. Except for forming such a lower film and a resist film, a pattern can be formed according to the above-described steps.

Next, the second pattern forming method of the present invention will be described in detail.

The second pattern forming method of the present invention comprises the steps of forming a lower layer film on a film to be processed, forming a resist film containing a phenolic resin on the lower layer film,
A step of pattern-exposing the resist film using a first light, a step of developing the exposed resist film to form a resist pattern, and a step of forming a second resist on the lower film using the resist pattern as a mask. Irradiating the exposed portion of the underlayer film with a developing process, wherein the underlayer film has a substituent capable of being decomposed by an acid and generates an alkali-soluble group after decomposition; and The method for forming a pattern, wherein the composition for an underlayer film is formed from a composition for an underlayer film, the composition comprising an acid generator that generates a compound, wherein the composition for an underlayer film contains a polycyclic aromatic hydrocarbon group.

In the second pattern forming method of the present invention, the film to be processed may be the same as that in the first pattern forming method. A silicon oxide film; a silicon nitride film; a silicon oxynitride film; spin-on glass; a silicon-based insulating film such as a blank material used in manufacturing a mask or the like; a silicon-based material such as amorphous silicon, polysilicon, or a silicon substrate; Examples include, but are not limited to, wiring materials and electrode materials such as aluminum, aluminum silicide, copper, tungsten, tungsten silicide, cobalt silicide, and ruthenium.

The underlayer film formed on the film to be processed contains a compound having a substituent capable of being decomposed by an acid and generating an alkali-soluble group after the decomposition, and an acid generator capable of generating the acid. The underlayer film composition contains a polycyclic aromatic hydrocarbon group. That is, an underlayer film is formed using the third underlayer film composition of the present invention.

The step of forming a pattern by using the composition according to the second method of the present invention will be described in detail below with reference to the drawings.

FIG. 4 is a sectional view showing an example of the steps of the second pattern forming method of the present invention.

First, as shown in FIG. 4A, a lower film 7 is formed on a film 6 to be processed formed on a substrate. The lower layer film can be formed by applying the third composition of the present invention onto a film to be processed by, for example, a spin coating method, a dipping method, or the like, and then baking it at a predetermined temperature as needed. The lower film has a wavelength range of 150
It is preferable to have a substituent that is decomposed by an acid generated from an acid generator when irradiated with light having any wavelength of from 230 nm.

Next, as shown in FIG. 4B, a resist film 8 is formed on the lower film 7. As a resist composition for forming a resist film, a resist composition containing a phenolic resin is used. As such a resist composition,
For example, a positive resist (IX-770, manufactured by Nippon Synthetic Rubber Co., Ltd.) containing naphthoquinonediazide and a novolak resin, a positive chemically amplified resist containing a polyvinylphenol resin protected with t-BOC and an acid generator ( A
PEX-E, manufactured by Shipley Corp.), and a positive chemically amplified resist (UVIIHS, manufactured by Shipley Corp.) containing a polyvinylphenol resin obtained by copolymerizing tertiary butyl methacrylate and an acid generator, and the like.
It is not limited to these.

The resist film 8 is formed by applying such a resist composition on the lower layer film 7 by a method such as spin coating or dipping, and performing baking at a predetermined temperature if necessary.

With respect to the resist film 8 thus formed,
Pattern exposure is performed as shown in FIG. That is, the first exposure light 9 is applied to the resist film 8 via a mask having a desired pattern. As the exposure light 9, visible light, ultraviolet light, or the like can be suitably used. As a light source for irradiating ultraviolet light, for example, a mercury lamp, XeF
(Wavelength = 351 nm), XeCl (wavelength = 308 n)
m), KrF (wavelength = 248 nm), KrCl (wavelength =
Excimer laser such as 222 nm). Further, pattern exposure may be performed using an electron beam, an ion beam, or X-rays.

In particular, the first exposure light has a wavelength range of 2
It is preferable to use light containing any wavelength of 40 to 450 nm. This is because light having a wavelength in this range is absorbed by the polycyclic aromatic hydrocarbon contained in the lower film, and the lower film effectively functions as an antireflection film.

By the pattern exposure, a latent image 10 is formed on the exposed portion of the resist film 8.

After the latent image is formed, the resist film 8 is developed with a predetermined developing solution to dissolve and remove the latent image portion of the resist film, thereby forming a resist pattern as shown in FIG. You. The developer used here can be appropriately selected according to the resist material. For example,
Tetramethylammonium hydroxide solution, choline,
Alkaline developers such as sodium hydroxide, potassium hydroxide and the like.

Using the obtained resist pattern as a mask, as shown in FIG.
Is applied to the lower film 7. As the second exposure light 11,
Light containing any wavelength in the wavelength range of 150 to 230 nm is used. As a light source for irradiating the second exposure light, an ArF excimer laser (wavelength = 193n)
m), an F ₂ laser (wavelength = 151 nm), an excimer lamp, and the like.

The phenolic resin contained in the resist film 8 has a high absorption for these wavelengths. For this reason, the second exposure light 11 permeates only a few nm on the surface of the resist film. Therefore, at the surface portion in the resist film, the phenolic resin causes a crosslinking reaction at these exposure wavelengths, and the surface crosslinked layer 12 is formed.

On the other hand, in the lower layer film 7, the resist pattern serves as a mask, and the region of the lower layer film covered with the resist pattern is not exposed. Conversely, a region not covered by the resist pattern is exposed, so that a latent image is formed in the underlayer film.

Note that the second exposure light has a wavelength range of 1
It is preferable to use light including any wavelength of 50 to 230 nm. This is for the following reasons.
That is, the phenolic resin contained in the resist film 8 has high absorbency at these wavelengths. For this reason, the second exposure light 11 permeates only a few nm on the surface of the resist film.

After the latent image is formed on the lower layer film, the latent image portion of the lower layer film is dissolved and removed by developing the lower layer film with a predetermined developer to form a pattern as shown in FIG. Is done. The developer used here can be appropriately selected according to the material of the lower layer film. For example, an alkali developing solution such as a tetramethylammonium hydroxide solution, choline, sodium hydroxide, potassium hydroxide and the like can be mentioned.

In the second pattern forming method of the present invention, an underlayer film is formed using a composition for an underlayer film containing a polycyclic aromatic hydrocarbon group. This polycyclic aromatic hydrocarbon group has a high light absorbency in a wavelength range of 240 to 450 nm,
It has high transparency to light in a wavelength range of 150 to 230 nm. The resist film formed on the lower film contains a phenolic resin, and the phenolic resin does not transmit light in a wavelength range of 150 to 230 nm.

In the second pattern forming method of the present invention, first, the resist film as described above is irradiated with first light. This first light has a wavelength range of 240 to 45.
Since it includes any one of the wavelengths of 0 nm, the reflection of the exposure light to the resist film is reliably suppressed by the function of the lower layer film. Therefore, a resist pattern having an excellent sectional shape can be formed.

After the resist pattern is thus formed, the entire surface is irradiated with the second exposure light. The second light is light including any wavelength in the wavelength range of 150 to 230 nm. Since the phenolic resin contained in the resist pattern does not transmit light in this wavelength range, the resist pattern functions as a mask. Therefore, the region of the lower film that is not covered with the resist pattern is selectively exposed to light, and the exposed portion of the lower film exhibits alkali solubility. Moreover, since the lower layer film contains a polycyclic aromatic hydrocarbon group having high transparency to light in a wavelength range of 150 to 230 nm, even the lower layer film having a large thickness is exposed to the bottom. be able to. Further, when the second exposure light is applied, an acid is generated from the acid generator contained in the lower film and diffuses to the bottom of the lower film. Therefore, even in the case of an underlayer film having a large thickness, it has vertical side walls,
In addition, it is possible to form a pattern having a good rectangular cross section.

By selectively etching the work film 6 using the resist pattern and the lower layer film pattern thus formed as an etching mask, the work film can be finely processed with high dimensional accuracy.

The second pattern forming method of the present invention can be suitably used for hybrid exposure in which a resist film is irradiated using a charged beam in addition to light exposure.

Examples of the charged beam include an ion beam and an electron beam. Such a charged beam is irradiated with the above-mentioned first light on the resist film,
Alternatively, the resist film is irradiated with the first light after irradiating the resist film. By irradiating the charged beam, the acid generator contained in the lower film is decomposed, and a conductive substance is generated in the exposed portion of the lower film. Since the charge is released to the surroundings by the conductive material, the displacement due to the charge accumulation is suppressed. Therefore, after the resist film is developed, it is possible to form a resist pattern having vertical sidewalls and a good rectangular cross section.

Next, the third pattern forming method of the present invention will be described in detail.

In the third pattern forming method of the present invention, a lower film containing a compound having a substituent which is decomposed by an acid and generating an alkali-soluble group after decomposition, and an acid generator which generates the acid are used as a film to be processed. Forming a resist film containing a phenolic resin on the lower film, pattern-exposing the resist film using a charged beam, and developing the exposed resist film. Forming a resist pattern, irradiating light using the resist pattern as a mask, and developing the exposed portion of the underlayer film.

In the third pattern forming method of the present invention, the film to be processed may be the same as the first and second pattern forming methods described above. A silicon oxide film; a silicon nitride film; a silicon oxynitride film; spin-on glass; a silicon-based insulating film such as a blank material used in manufacturing a mask or the like; a silicon-based material such as amorphous silicon, polysilicon, or a silicon substrate; Examples include, but are not limited to, wiring materials and electrode materials such as aluminum, aluminum silicide, copper, tungsten, tungsten silicide, cobalt silicide, and ruthenium.

The lower layer film formed on the film to be processed is formed of a compound containing a compound having a substituent capable of decomposing by an acid and generating an alkali-soluble group after decomposition, and a composition containing an acid generator generating the acid. You. That is, the first of the present invention
An underlayer film is formed using the underlayer film composition.

The lower layer film is formed by using the first composition of the present invention, the first exposure light is changed to a charged beam, and the above-mentioned second exposure light is used except that a predetermined light is used as the second exposure light. The pattern can be formed by the third method of the present invention in the same manner as the pattern forming method of the above.

As the charged beam which can be used in the third pattern forming method of the present invention, an ion beam, an electron beam and the like can be mentioned.

By irradiating such a charged beam, the acid generator contained in the lower layer film is decomposed, and a conductive substance is generated in the exposed portion of the lower layer film. Since the charge is released to the surroundings by the conductive material, the displacement due to the charge accumulation is suppressed. Therefore, after the resist film is developed, it is possible to form a resist pattern having vertical sidewalls and a good rectangular cross section.

Light with which the lower layer film is irradiated using the obtained resist pattern as a mask has a wavelength range of 150 to 230 nm.
It is preferable that the light contains any one of the above wavelengths. This is for the following reasons. That is, the phenolic resin contained in the resist pattern does not transmit light in this wavelength range, so that the resist pattern functions as a mask.

Upon irradiation with light in the above-described wavelength range, an acid is generated from the acid generator contained in the underlayer film,
It diffuses to the bottom of this lower film. Therefore, even in the case of the lower layer film having a large thickness, it is possible to form a pattern having vertical sidewalls and a rectangular cross section having a good shape.

By selectively etching the target film 6 using the resist pattern and the lower layer pattern thus formed as an etching mask, the target film can be finely processed with high dimensional accuracy.

[0160]

EXAMPLES First, each component used in Examples and Comparative Examples is shown below.

[0161]

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[0162]

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[0163]

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[0164]

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[0165]

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These compounds were blended according to the respective formulations to prepare compositions for lower layer films of Examples and Comparative Examples, and patterns were formed using the obtained compositions.

Example 1 10 g of the compound (1-1) having a weight-average molecular weight of 11,000 as a dissolution inhibitor and 1 g of the compound (3-1) as an acid generator were dissolved in 89 g of cyclohexanone. A solution material was prepared.

Using the obtained solution material, an anti-reflection film as a lower layer film was formed, and an anti-reflection film pattern was formed according to the process shown in FIG.

First, a BPSG film as a film to be processed 1 was formed to a thickness of 500 nm on a silicon substrate by LPCVD. On the film to be processed, the above-mentioned solution material for the lower layer film was applied by a spin coating method, and baked at 130 ° C. for 180 seconds using a hot plate. Thereby, as shown in FIG. 2A, an antireflection film 2a as a lower layer film was formed with a thickness of 200 nm. The complex refractive index of the antireflection film 2 at a wavelength of 248 nm is n = 1.78, k =
0.49.

A positive chemically amplified resist KRF M20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied on the antireflection film 2a and baked on a hot plate at 140 ° C. for 90 seconds, as shown in FIG. 2 (b). Thus, a resist film 3a was formed. At this time, the thickness of the resist film 3a is 200 nm.

A stepper (NA = 0.6, σ = 0.5) using a reduced optical KrF excimer laser 4 as a light source is applied to the obtained resist film 3a and antireflection film 2a.
Then, pattern exposure was performed as shown in FIG.
At this time, the exposure amount was 28 mJ / cm ² .

Then, at 140 ° C. on a hot plate, 9
By performing baking for 0 second, the resist film 3
a and a 0.15 μm line and space pattern latent image 5a as shown in FIG.
Was formed.

Subsequently, the latent image 5a formed on the resist film 3a and the antireflection film 2a is dissolved and removed by performing paddle development with a 0.21N aqueous solution of tetramethylammonium hydroxide for 30 seconds. 2
A pattern as shown in (d) was formed.

When the cross section of the pattern obtained as described above was observed using a scanning electron microscope, it was confirmed that the antireflection film 2a had been developed in a vertical shape as shown in FIG. Was confirmed. The thickness of the resist film 3a after the anti-reflection film was developed was 190 nm. Since the thickness of the antireflection film is 200 nm, the thickness of the mask material pattern including the antireflection film pattern and the resist pattern is 390 nm. This thickness is sufficient as a mask required for etching the film to be processed (BPSG film) in the next step.

Since the return light to the resist film was sufficiently suppressed by the action of the antireflection film, no wavy shape due to the standing wave was generated on the side wall of the resist pattern. Therefore, a pattern having a good shape having vertical side walls and a rectangular cross section was formed.

(Comparative Example 1) 10 g of polysulfone was dissolved in 90 g of cyclohexanone to prepare a solution material for the lower layer film.

Using the obtained solution material, an antireflection film as a lower layer film was formed, and an antireflection film pattern was formed according to the process shown in FIG.

First, a BPSG film as the film to be processed 13 was formed on a silicon substrate to a thickness of 500 nm by using the LPCVD method. On the film to be processed, the above-mentioned solution material for the lower layer film was applied by a spin coating method, and baked at 180 ° C. for 180 seconds using a hot plate. Thereby, as shown in FIG. 5A, the antireflection film 14 as a lower layer film was formed with a thickness of 200 nm. Anti-reflection film 14
The complex refractive index at a wavelength of 248 nm is n = 1.78, k =
0.24.

A positive chemically amplified resist KRF M20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied on the antireflection film 14 and baked on a hot plate at 140 ° C. for 90 seconds, as shown in FIG. 5B. Thus, a resist film 15 was formed. At this time, the thickness of the resist film 15 is 200 nm.

The obtained resist film 15 was patterned with a stepper (NA = 0.6, σ = 0.5) using a reduction optical KrF excimer laser 16 as a light source, as shown in FIG. Exposure was performed. At this time, the exposure amount is 28
mJ / cm ² .

Thereafter, using a hot plate at 140 ° C.
5B, a latent image 17 having a 0.15 μm line and space pattern was formed on the resist film 15 as shown in FIG. 5C.

Subsequently, the latent image 17 formed on the resist film 15 is dissolved and removed by performing paddle development with a 0.21 N aqueous solution of tetramethylammonium hydroxyside for 30 seconds, thereby obtaining the image shown in FIG. A resist pattern as shown was formed.

Using the obtained resist pattern as a mask, the antireflection film 14 was etched by a dry etching method. For the etching, a magnetron type parallel plate type RIE apparatus was used, and the etching conditions were source gas O ₂ = 50 SCCM, CF ₄ = 200 S.
CCM, excitation power was 800 W, and degree of vacuum was 80 mTorr.

When the etching of the antireflection film 14 was completed, the processed shape was observed with a scanning microscope.
As shown in FIG. 5E, the resist pattern collapsed during the etching of the antireflection film and almost disappeared. For this reason, the antireflection film could not be processed vertically.

As can be seen from this comparative example, when the antireflection film was patterned by the dry etching method, if the resist film thickness was reduced in order to enhance the resolution, the resist pattern was also cut along with the antireflection film. Would. Therefore, the mask material pattern composed of the resist pattern and the antireflection film pattern cannot secure a film thickness required for etching the film to be processed (BPSG film) in a later step.

On the other hand, according to the method of the present invention, Embodiment 1
As shown in (2), even when the thickness of the antireflection film is large, the resist pattern can be transferred to the antireflection film without causing the resist pattern to be reduced in film thickness. as a result,
The mask material pattern including the resist pattern and the antireflection film pattern can secure a film thickness required for etching a film to be processed (BPSG film) in a later step.

(Comparative Example 2) 10 g of polyamic acid (manufactured by Toshiba Chemical Corporation: Chemitite CT4002T) was added to NMP90.
g to prepare a solution material for the lower layer film.

Using the obtained solution material, an antireflection film as a lower layer film was formed, and an antireflection film pattern was formed according to the process shown in FIG.

First, a BPSG film as the film to be processed 18 was formed on a silicon substrate to a thickness of 500 nm by using the LPCVD method. On the film to be processed, the above-mentioned solution material for the lower layer film was applied by a spin coating method, and baked at 180 ° C. for 180 seconds using a hot plate. As a result, as shown in FIG. 6A, an antireflection film 19 as a lower layer film was formed with a thickness of 200 nm. Anti-reflection film 19
Has a complex refractive index of n = 1.74 and k =
0.32.

A positive chemically amplified resist KRF M20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied on the antireflection film 19 and baked on a hot plate at 140 ° C. for 90 seconds, as shown in FIG. 6B. Thus, a resist film 20 was formed. At this time, the thickness of the resist film 20 is 200 nm.

The resulting resist film 20 was patterned by a stepper (NA = 0.6, σ = 0.5) using a reduced optical KrF excimer laser 21 as a light source, as shown in FIG. Exposure was performed. At this time, the exposure amount is 27
mJ / cm ² .

After that, using a hot plate at 140 ° C.
6B, a latent image 22 having a 0.15 μm line and space pattern was formed on the resist film 20 as shown in FIG. 6C.

Subsequently, the latent image 22 formed on the resist film 20 is developed by performing paddle development with a 0.21 N aqueous solution of tetramethylammonium hydroxyside for 30 seconds.
Then, a pattern was formed by dissolving and removing the portion of the antireflection film 19 below this.

The composition for an underlayer film used in this comparative example is soluble in an alkali developing solution. Therefore, when the resist film is developed, it is possible to simultaneously dissolve and remove the exposed portion of the resist film and the portion not covered with the resist pattern. However, the anti-reflection film 19
In (2), since the development proceeds isotropically, the processed shape of the antireflection film pattern after the development processing becomes a cut-off shape as shown in FIG. 6 (d) and cannot be anisotropically developed. Was.

Comparative Example 3 1 g of anthracene as a dye was added to 99 g of an i-ray resist IX770 (manufactured by Nippon Synthetic Rubber Co., Ltd.) to prepare a solution material for an underlayer film.

Using the obtained solution material, an anti-reflection film was formed as a lower layer film, and an anti-reflection film pattern was formed according to the process shown in FIG.

First, a BPSG film to be processed 23 was formed to a thickness of 500 nm on a silicon substrate by LPCVD. On the film to be processed, the above-mentioned solution material for the lower layer film was applied by a spin coating method, and baked at 180 ° C. for 180 seconds using a hot plate. Thus, as shown in FIG. 7A, an antireflection film 24 as a lower layer film was formed with a thickness of 200 nm. Anti-reflection film 24
The complex refractive index at a wavelength of 248 nm is n = 1.68, k =
0.20.

A positive chemically amplified resist KRF M20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied on the antireflection film 24, and baked on a hot plate at 140 ° C. for 90 seconds, as shown in FIG. 7B. Thus, a resist film 25 was formed. At this time, the thickness of the resist film 25 is 200 nm.

The obtained resist film 25 and antireflection film 24 are applied to a reduction optical KrF excimer laser 26.
Stepper with a light source (NA = 0.6, σ = 0.5)
Then, pattern exposure was performed as shown in FIG.
At this time, the exposure amount was 30 mJ / cm ² .

Thereafter, using a hot plate at 140 ° C.
9B, a latent image 27 having a 0.15 μm line and space pattern was formed on the resist film 25 and the antireflection film 24 as shown in FIG. 7C.

Subsequently, the latent image 27 formed on the resist film 25 and the antireflection film 24 is dissolved and removed by performing paddle development for 30 seconds with a 0.21 N tetramethylammonium hydroxyside aqueous solution. 7
A pattern as shown in (d) was formed.

The composition for the underlayer film used for forming the antireflection film in this comparative example causes a photosensitive reaction by exposure light having a wavelength of 248 nm, and the portion where the photosensitive reaction occurs shows solubility in an alkali developing solution. However, since the antireflection film has high light absorption at a wavelength of 248 nm, the photosensitive reaction does not proceed to the bottom of the antireflection film. As a result, after the anti-reflection film has been subjected to the developing treatment, a layer 28 is left as shown in FIG. 7D.

Comparative Example 4 This comparative example is a comparative example in which an anti-reflection film as a lower layer film is processed by using the PCM method in Comparative Example 1.

First, in the same manner as in Comparative Example 1, FIG.
A resist pattern as shown in (d) was formed. Thereafter, an excimer lamp having a bandwidth of 20 nm centered on a wavelength of 172 nm is irradiated from above the resist pattern,
An area not covered with the resist pattern of the antireflection film was exposed. The irradiation amount at this time was 2.0 J / cm ² .

The resist film used in this comparative example has a wavelength of 17
Low transmittance for ultraviolet light of 2 nm. Therefore, the excimer lamp penetrates only a few nm of the surface layer of the resist pattern, and the exposed portion of the antireflection film (the area not covered with the resist pattern) can be selectively exposed.

Next, the photosensitive portion of the anti-reflection film was dissolved and removed using anisole, and development was performed to pattern the anti-reflection film. When the shapes of the resist pattern and the antireflection film pattern were observed with a scanning electron microscope,
One more residue was left, and the antireflection film could not be processed vertically. When the irradiation amount of the excimer lamp was further increased, no more residue remained at 3.0 J / cm ² or more. However, a photoreaction occurred in the resist pattern, and the pattern was deformed, and could not be used as a mask material for a film to be processed.

As in this comparative example, a method of using a photo-decomposable resin as the lower layer film, forming a resist pattern, and then irradiating light to decompose the lower layer film to remove it by development is performed in the following manner. It has a large problem that the resist pattern is deformed. In the present invention, since the lower layer film is patterned by an acid catalyzed reaction, the sensitivity is high, and the lower layer film can be patterned without deforming the resist pattern.

Example 2 9 g of the compound (1-2) having a weight average molecular weight of 12,000 as a dissolution inhibitor and 1 g of the compound (1-3) as a dissolution inhibitor were dissolved in 89 g of cyclohexanone. Materials were prepared.

Using the obtained solution material, an antireflection film as a lower layer film was formed, and an antireflection film pattern was formed according to the process shown in FIG.

First, an SiO ₂ film serving as the film to be processed 1 was formed on a silicon substrate to a thickness of 500 nm by a sputtering method. On the film to be processed, the above-mentioned solution material for the lower layer film was applied by spin coating, and baked at 150 ° C. for 180 seconds using a hot plate. Thereby, as shown in FIG. 2A, the anti-reflection film 2 as a lower film is formed.
a was formed to a thickness of 200 nm. The complex refractive index of light having a wavelength of 248 nm of the antireflection film 2a is n = 1.65, k =
0.62.

On the other hand, 9.9 g of polyvinyl phenol (weight average molecular weight of about 13,000) in which 30% of the hydroxyl groups were protected with a tertiary butoxycarbonyl group, and 0.1 g of sulfonimide as an acid generator and 90 g of ethyl lactate To prepare a solution material for a positive chemically amplified resist. This solution material is applied to the aforementioned anti-reflection film 2a.
And baked on a hot plate at 110 ° C. for 90 seconds to form a 200 nm-thick resist film 3a.
Was formed.

A stepper (NA = 0.6, σ = 0.5) using a reduced optical KrF excimer laser beam as a light source is applied to the obtained resist film 3a and antireflection film 2a.
Then, pattern exposure was performed as shown in FIG.
At this time, the exposure amount was 24 mJ / cm ² .

Then, at 110 ° C. on a hot plate, 9
By performing baking for 0 second, the resist film 3
a and a 0.18 μm line-and-space pattern latent image 5a as shown in FIG.
Was formed.

Subsequently, the latent image 5a formed on the resist film 3a and the antireflection film 2a is dissolved and removed by performing paddle development with a 0.21N aqueous solution of tetramethylammonium hydroxyside for 30 seconds. 2
A pattern as shown in (d) was formed.

When the cross section of the pattern obtained as described above was observed using a scanning electron microscope, it was confirmed that the antireflection film 2a was developed in a vertical shape as shown in FIG. Was confirmed.

As described above, in the method of the present invention, as long as the resist film contains an acid generator, the antireflection film may not contain the acid generator. An acid is generated from the acid generator in the resist film by the exposure, and the acid decomposes the dissolution inhibitor in the antireflection film, so that a pattern having vertical side walls and a rectangular cross section having a good shape is obtained. Can be formed.

(Embodiment 3) First, a)
To d), four types of solution materials for the lower layer film were prepared.

A) As a dissolution inhibitor, a weight average molecular weight of 8,
9.9 g of the compound (1-2) and 0.1 g of the compound (3-2) as an acid generator.
Dissolved in 0.0 g.

B) Weight average molecular weight 1 as dissolution inhibitor
9 g of the 2,000 compound (1-4) and 1 g of the compound (3-3) as an acid generator were dissolved in 90 g of cyclohexanone.

C) Weight average molecular weight 1 as a dissolution inhibitor
9.8 g of 1,000 compound (1-5) and 0.2 g of compound (3-2) as an acid generator are mixed with 90 g of anisole.
Was dissolved.

D) Weight average molecular weight 1 as dissolution inhibitor
4 g of the compound (1-1) having a molecular weight of 2,000, 0.2 g of the compound (3-2) as an acid generator, and compound (2-1) having a weight average molecular weight of 8,000 as an alkali-soluble resin.
8 g was dissolved in 90 g of cyclohexanone.

Using each of the obtained solution materials, an anti-reflection film as a lower layer film was formed, and an anti-reflection film pattern was formed as follows.

A TEOS oxide film as a film to be processed was formed to a thickness of 500 nm on a silicon substrate by using the LPCVD method. The solution material of the above-mentioned lower layer film was applied onto the film to be processed, respectively, and baked on a hot plate. The baking was performed at a baking temperature shown in Table 1 below for 90 seconds. Thus, an anti-reflection film as a lower layer film having a thickness of 200 nm was formed. The results of measuring the complex refractive index at a wavelength of 248 nm of each antireflection film are summarized in Table 1 below.

A positive chemically amplified resist KRF M20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied on each antireflection film.
Baking was performed at 140 ° C. for 90 seconds on a hot plate to form a resist film. At this time, the thickness of the resist is 200 nm.

The resulting resist film and antireflection film were subjected to pattern exposure using a stepper (NA = 0.6, σ = 0.5) using a reduction optical KrF excimer laser as a light source. At this time, the exposure amount was 24 mJ / cm ² .

Thereafter, 9 ° C. on a hot plate at 140 ° C.
By performing baking for 0 second, a latent image having a 0.15 μm line and space pattern was formed on the resist film and the antireflection film.

Subsequently, paddle development is performed for 30 seconds with an aqueous solution of 0.21 N tetramethylammonium hydroxyside to dissolve and remove the latent image formed on the resist film and the antireflection film, thereby forming the resist film and the reflection film. A 0.15 μm line and space pattern was formed on the prevention film.

When the cross section of the pattern was observed using a scanning electron microscope, it was found that, regardless of the combination of any of the antireflection films and the resist, there was no wavy shape attributable to the standing wave on the side wall of the resist pattern. The standing wave is sufficiently suppressed even in the prevention film. The shape of the anti-reflection film after the development treatment is also good in a vertical shape.

The thickness of the resist pattern after the anti-reflection film has been developed is summarized in Table 1 below.

[0230]

[Table 1]

As shown in Table 1, the amount of film reduction of the resist pattern is within a very small value of 10 nm or less. Since the thickness of the antireflection film is 200 nm,
The mask material pattern composed of the antireflection film pattern and the resist pattern has a thickness of 390 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (TEOS oxide film) in the next step.

(Example 4) First, a)
To d), four types of solution materials for the lower layer film were prepared.

A) Melamine-formaldehyde resin 10
g, 0.5 g of compound (3-1) as an acid generator and 2 g of compound (p-14) as an alkali-soluble resin,
Dissolved in 87.5 g of anisole.

B) 10 g of a urea-formaldehyde resin,
0.5 g of compound (3-2) as an acid generator and 2 g of compound (p-12) as an alkali-soluble resin were dissolved in 87.5 g of anisole.

C) Glycol-formaldehyde resin 1
0 g, 0.5 g of compound (3-3) as an acid generator, and 2 g of compound (p-11) as an alkali-soluble resin were dissolved in 87.5 g of anisole.

D) 10 g of melamine resin, 2 g of urea resin,
Then, 0.5 g of sulfonimide as an acid generator was dissolved in 87.5 g of anisole.

Using each of the obtained solution materials, an antireflection film as a lower layer film was formed, and an antireflection film pattern was formed according to the process shown in FIG.

On a silicon substrate, a spin-on-glass film as a film to be processed 1 was formed with a thickness of 500 nm using a spin-on-glass product name R7 (manufactured by Hitachi Chemical Co., Ltd.). The solution material of the above-mentioned lower layer film is applied on the film to be processed,
Each was baked on a hot plate. The baking was performed at a baking temperature shown in Table 2 below for 60 seconds. Thereby, the film thickness 20 as shown in FIG.
An antireflection film 2b as a lower layer film of 0 nm was formed.
The results of measuring the complex refractive index at a wavelength of 248 nm of each antireflection film are summarized in Table 2 below.

On each antireflection film, a negative chemically amplified resist SNR200 (manufactured by Shipley Co.) was applied, and baked on a hot plate at 140 ° C. for 90 seconds.
A resist film 3b as shown in FIG. At this time, the thickness of the resist film 3b is 200 nm.

The obtained resist film 3b and antireflection film 2b were applied to a stepper (NA = 0.6, σ = 0.7) using a reduction optical KrF excimer laser as a light source.
Pattern exposure was performed as shown in FIG. The exposure amount at this time was 98 mJ / cm ² .

Thereafter, 9 hours at 125 ° C. on a hot plate.
By performing baking for 0 second, the resist film 3
b and the antireflection film 2b have a latent image 5b having a line and space pattern of 0.25 μm as shown in FIG.
Was formed, and the resist film and the antireflection film in the latent image portion were crosslinked.

Subsequently, paddle development was performed for 30 seconds using an aqueous 0.14 N tetramethylammonium hydroxide solution to dissolve and remove portions other than the latent image formed on the resist film 3b and the antireflection film 2b. As a result, as shown in FIG. 3D, a 0.25 μm line and space pattern was formed on the resist film and the antireflection film.

When the cross section of the pattern was observed using a scanning electron microscope, it was found that, regardless of the combination of any of the antireflection films and the resist, there was no wavy shape attributable to the standing wave on the side wall of the resist pattern. The standing wave is sufficiently suppressed even in the prevention film. The shape of the anti-reflection film after the development processing is also a good vertical shape.

Table 2 below summarizes the thickness of the resist pattern after the antireflection film has been developed.

[0245]

[Table 2]

As shown in Table 2, the amount of film reduction of the resist pattern is within a very small value of 10 nm or less. Since the thickness of the antireflection film is 200 nm,
The mask material pattern composed of the antireflection film pattern and the resist pattern has a thickness of 390 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (spin-on-glass) in the next step.

As described above, in the first pattern forming method of the present invention, a negative resist can be used. In this case, the resist film in the exposed portion and the anti-reflection film in the exposed portion are left cross-linked to form a pattern.

(Example 5) First, a)-
d) Four types of solution materials for the lower layer film were prepared.

A) Weight average molecular weight 1 as dissolution inhibitor
9.8 g of 5,000 compound (1-1) and 0.2 g of compound (3-3) as an acid generator were dissolved in 90 g of cyclohexanone.

B) Weight average molecular weight 1 as dissolution inhibitor
9.8 g of 7,000 compound (1-5), 2 g of compound (1-7) as a dissolution inhibitor, and 0.2 g of compound (3-3) as an acid generator were dissolved in 88 g of cyclohexanone.

C) Weight average molecular weight 1 as dissolution inhibitor
4.8 g of the compound (1-5) of 6,000, 4 g of the compound (2-2) as an alkali-soluble resin, and 0.2 g of the compound (3-1) as an acid generator were dissolved in 91 g of anisole.

D) Weight average molecular weight 1 as dissolution inhibitor
9.8 g of 5,000 compound (1-6), 2 g of compound (2-3) as an alkali-soluble resin, and 0.2 g of compound (3-1) as an acid generator were dissolved in 87 g of xylene.

Using each of the obtained solution materials, an antireflection film was formed as a lower layer film, and an antireflection film pattern was formed as follows.

An SiN film to be processed was formed to a thickness of 500 nm on a silicon substrate by LPCVD. The solution material for the lower layer film was applied onto the film to be processed and baked on a hot plate. The baking was performed at a baking temperature shown in Table 3 below for 90 seconds. Thus, an anti-reflection film as a lower layer film having a thickness of 200 nm was formed. The results of measuring the complex refractive index of each antireflection film at a wavelength of 193 nm are summarized in Table 3 below.

On the other hand, the compound (1-
8) 9.8 g, compound (1-9) 2 as dissolution inhibitor
g, and 0.2 g of compound (3-4) as an acid generator
Was dissolved in 87 g of ethyl lactate to prepare a resist solution material. This solution material was applied on each of the above-described antireflection films, and baked on a hot plate at 110 ° C. for 90 seconds to form a 200 nm-thick resist film.

The obtained resist film and antireflection film were subjected to pattern exposure using an ArF exposure apparatus (NA = 0.55, σ = 0.7). The exposure amount at this time is 32 mJ
/ Cm ² .

Then, at 110 ° C. on a hot plate, 9
By performing baking for 0 second, a latent image having a 0.20 μm line and space pattern was formed on the resist film and the antireflection film.

Subsequently, paddle development is performed for 30 seconds with an aqueous solution of tetramethylammonium hydroxide at 0.21 N to dissolve and remove the latent images formed on the resist film and the antireflection film, thereby forming the resist film and the reflection film. A 0.20 μm line and space pattern was formed on the prevention film.

When the cross section of the pattern was observed using a scanning electron microscope, it was found that, regardless of the combination of any of the antireflection films and the resist, there was no wavy shape attributable to the standing wave on the side wall of the resist pattern. The standing wave is sufficiently suppressed even in the prevention film. The shape of the anti-reflection film after the development processing is also a good vertical shape.

Table 3 below summarizes the thickness of the resist pattern after developing the resist film and the antireflection film.

[0261]

[Table 3]

As shown in Table 3, the amount of film reduction of the resist pattern is within a very small value of 10 nm or less. Since the thickness of the antireflection film is 200 nm,
The mask material pattern composed of the antireflection film pattern and the resist pattern has a thickness of 390 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (SiN film) in the next step.

(Embodiment 6) First, a)
To g) of seven types of lower layer film solution materials were prepared.

A) Weight average molecular weight 1 as dissolution inhibitor
9.8 g of 4,000 compound (1-1) and 0.2 g of compound (3-1) as an acid generator were dissolved in 90 g of cyclohexanone.

B) Weight average molecular weight 1 as dissolution inhibitor
8 g of the compound (1-2) of 7,000 and 1.8 of the compound (1-7) having a weight average molecular weight of 13,000 as a dissolution inhibitor.
g, and 0.2 g of compound (3-1) as an acid generator
Was dissolved in 90 g of cyclohexanone.

C) Weight average molecular weight 1 as dissolution inhibitor
3.8 g of the compound (1-11) of 5,000, 6 g of the compound (1-3) as a dissolution inhibitor, and 0.2 g of the compound (3-1) as an acid generator were dissolved in 90 g of cyclohexanone.

D) Weight average molecular weight 1 as dissolution inhibitor
9.8 g of compound (1-12) of 5,000, 1 g of anthraquinone as a dye, and compound (3) as an acid generator
-4) 0.2 g was dissolved in 89 g of cyclohexanone.

E) Weight average molecular weight 1 as dissolution inhibitor
9.8 g of the compound (1-4) of 3,000 and 0.2 g of the compound (3-3) as an acid generator are mixed with 90 g of ethyl lactate.
Was dissolved.

F) Weight average molecular weight 1 as dissolution inhibitor
4.8 g of 4,000 compound (1-12), compound (1-3) having a weight average molecular weight of 18,000 as a dissolution inhibitor
5 g, and 0.2 g of compound (3-2) as an acid generator
Was dissolved in 90 g of cyclohexanone.

G) As a dissolution inhibitor, weight average molecular weight 1
8 g of the compound (1-1) having a weight average molecular weight of 15,000 as an alkali-soluble resin.
1) 3.8 g and compound (3-4) as an acid generator
0.2 g was dissolved in 88 g of cyclohexanone.

Using each of the obtained solution materials, an anti-reflection film as a lower layer film was formed, and an anti-reflection film pattern was formed according to the process shown in FIG.

A 700 nm-thick TEOS oxide film as the film to be processed 7 was formed on a silicon substrate by using the LPCVD method. The solution material for the lower layer film was applied onto the film to be processed and baked on a hot plate. Baking was performed for 90 seconds at the pre-bake temperature shown in Table 4 below. As a result, FIG.
As shown in (a), the antireflection film 7 as the lower film
It was formed with a thickness of 0 nm. Wavelength 248 of antireflection film 7
The results of measuring the complex refractive index in nm are summarized in Table 4 below.

Each of the anti-reflection films was coated with the resist solution prepared in Example 2 described above, and baked on a hot plate at 140 ° C. for 90 seconds.
A resist film 8 having a thickness of 200 nm as shown in FIG.

With respect to the obtained resist film 8, FIG.
As shown in the figure, a KrF exposure apparatus (NA = 0.60, σ =
0.65). The exposure amount at this time was 24 mJ / cm ² .

Thereafter, using a hot plate at 110 ° C.
Baking for 90 seconds in FIG.
As shown in (c), a latent image 10 having a contact hole pattern having a diameter of 0.20 μm was formed on the exposed portion of the resist film 8.

Subsequently, the latent image 10 formed on the resist film 8 was dissolved and removed by performing paddle development with a 0.21 N aqueous solution of tetramethylammonium hydroxide for 30 seconds. Thus, a contact hole pattern having a diameter of 0.20 μm was formed in the resist film as shown in FIG.

Subsequently, as shown in FIG.
After irradiating the entire surface of the wafer with an excimer lamp 11 having a bandwidth of 20 nm centered on 72 nm, the wafer was baked on a hot plate. In addition, the exposure amount of the excimer lamp was the exposure amount shown in Table 4, and the baking temperature was 90 seconds at the post-baking temperature shown in Table 4. Thereby, as shown in FIG. 4E, a latent image of a contact hole pattern having a diameter of 0.20 μm was formed on the antireflection film 7.

The light irradiated at this time penetrates only a few nm of the surface layer of the resist pattern, but reaches the bottom of the antireflection film 7. As a result, only the exposed portion of the antireflection film (the area not covered with the resist pattern) is exposed to light,
A latent image can be formed. Further, the surface of the resist pattern was crosslinked by this irradiation, and a surface crosslinked layer 12 was formed.

Finally, the developing solution having the normality shown in Table 4 was used to prepare 3
By performing paddle development for 0 second, the latent image formed on the antireflection film 7 was dissolved and removed. As a result, as shown in FIG. 4F, a contact hole pattern having a diameter of 0.20 μm was formed in the antireflection film.

When the cross section of the pattern was observed using a scanning electron microscope, it was found that, regardless of the combination of any of the antireflection films and the resist, there was no wavy shape attributable to the standing wave on the side wall of the resist pattern. The standing wave is sufficiently suppressed even in the prevention film. The shape of the anti-reflection film after the development treatment is also good in a vertical shape.

Table 4 below summarizes the thicknesses of the resist patterns after developing the resist film and the antireflection film.

[0282]

[Table 4]

As shown in Table 4, the amount of film reduction of the resist pattern is within a very small value of 10 nm or less. Since the thickness of the antireflection film is 400 nm,
The thickness of the mask material pattern including the antireflection film pattern and the resist pattern is 490 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (TEOS oxide film) in the next step.

This example shows that an antireflection film as thick as 400 nm can be processed into a vertical shape by using the method of the present invention.

(Embodiment 7) In this embodiment, an example will be described in which the second pattern forming method of the present invention is applied to processing of an insulating film necessary for forming a buried wiring by a dual damascene process.

In this embodiment, an antireflection film as a lower film is formed using the solution material prepared in Example 1 as a solution material for the lower film, and an antireflection film pattern is formed in accordance with the process shown in FIG. Formed.

First, a film thickness of 300 n was formed on a silicon wafer.
An aluminum film having a thickness of 800 nm is formed on the aluminum film by sputtering.
An oxide film was formed using the LPCVD method.

The lower layer film solution material prepared in Example 1 was applied on the TEOS oxide film and baked at 130 ° C. for 60 seconds to form an antireflection film as the lower layer film. At this time, the thickness of the antireflection film is 55 nm.

A positive chemically amplified resist KRF M20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied on the antireflection film, and baked on a hot plate at 140 ° C. for 90 seconds to form a resist film having a thickness of 200 nm. did.

A stepper (N) using a reduced optical KrF excimer laser beam as a light source is applied to the obtained resist film.
(A = 0.6, σ = 0.5).
The exposure amount at this time was 28 mJ / cm ² . Thereafter, the resist film and the antireflection film are baked on a hot plate at 110 ° C. for 90 seconds to obtain a resist film and an antireflection film having a thickness of 0.2%.
A latent image having a 0 μm line and space pattern was formed.

Subsequently, paddle development was performed for 30 seconds with a 0.21 N aqueous solution of tetramethylammonium hydroxyside to dissolve and remove the latent image formed on the resist film and the antireflection film. As a result, a 0.20 μm line and space pattern was formed on the resist film and the antireflection film.

Using the thus obtained resist pattern and antireflection film pattern as a mask, the TEOS oxide film was etched to a depth of 200 nm. For the etching, a magnetron type RIE apparatus was used, and the etching conditions were source gas C ₄ F ₈ = 10 SCCM,
Ar = 100 SCCM, CO = 50 SCCM, excitation power 800 W, degree of vacuum 80 mTorr, and substrate temperature 40 ° C.

Finally, the resist pattern and the antireflection film pattern were removed by ashing. In the ashing removal, a downflow type ashing apparatus is used, and the ashing conditions are O ₂ = 500 SCCM and excitation power of 80.
The temperature was 0 W, the degree of vacuum was 80 mTorr, and the substrate temperature was 200 ° C.

As shown in FIG. 8A, the TEOS oxide film 29 on the aluminum film 28 has a thickness of 0.20 μm.
An m-line and space groove was formed.

[0295] The TEOS oxide film 2 having the groove thus formed.
9 is coated with the solution material for the lower layer film prepared in Example 1 by spin coating, and
Baking at 0 ° C for 120 seconds. As a result, FIG.
As shown in FIG. 2B, a TEOS oxide film 2 having a line and space pattern of 0.20 μm with a depth of 200 nm
9 was embedded with an antireflection film 30 as a lower layer film.

The antireflection film formed of the material prepared in Example 1 has a glass transition temperature of 105 ° C.
By performing the baking, it flows into the groove of the TEOS oxide film 29 and can be completely filled. TE
The thickness (t ₁ ) of the anti-reflection film 30 at the convex portion of the OS oxide film 29 is 20 nm, and the thickness (t ₂ ) of the anti-reflection film 30 at the concave portion of the TEOS oxide film 29 is 220 nm.

On the antireflection film 30 thus formed,
Apply a positive chemically amplified resist KRFM20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) and apply 90 ° C at 140 ° C. on a hot plate.
After baking for 2 seconds, a resist film 31 was formed as shown in FIG. At this time, the thickness of the resist film 31 is 200 nm.

The resist film 31 obtained was subjected to a stepper (NA = 0.6, σ = 0.5) using a reduction optical KrF excimer laser beam 32 as a light source, as shown in FIG. Pattern exposure was performed. The exposure at this time is
29 mJ / cm ² .

Then, at 110 ° C. on a hot plate, 9
By performing the baking for 0 second, a latent image 33 of a contact hole pattern having a diameter of 0.15 μm was formed on the resist film 31 as shown in FIG. 8D. The position of this latent image 33 corresponds to the center of the groove formed in the TEOS oxide film.

Subsequently, paddle development was performed for 30 seconds using a 0.21 N aqueous solution of tetramethylammonium hydroxyside to dissolve and remove the latent image formed on the resist film 31. Thus, a contact hole pattern having a diameter of 0.15 μm was formed in the resist film as shown in FIG.

Thereafter, as shown in FIG. 8 (f), the entire surface of the wafer is irradiated with an ArF excimer laser 34,
A latent image 36 of a contact hole having a diameter of 0.15 μm was formed on the antireflection film 30. The irradiation amount at this time is 80 mJ /
cm ² . The surface of the resist pattern is cross-linked by the entire surface irradiation, and the surface cross-linked layer 3 as shown in FIG.
5 was formed.

Subsequently, the latent image 36 formed on the antireflection film 30 is dissolved and removed by performing paddle development with a 0.21 N tetramethylammonium hydroxyside aqueous solution for 30 seconds, thereby obtaining FIG. A contact hole pattern having a diameter of 0.15 μm was formed as shown in FIG.

By using the thus obtained resist pattern and antireflection film pattern as a mask, the TEOS oxide film 29 is dry-etched to obtain FIG.
A contact hole pattern having a diameter of 0.15 μm was formed in the TEOS oxide film 29 as shown in FIG. In the etching, a magnetron type RIE apparatus was used, and the etching conditions were source gas C ₄ F ₈ = 10 SCC.
M, Ar = 100 SCCM, CO = 50 SCCM, excitation power 800 W, degree of vacuum 80 mTorr, substrate temperature 40 ° C.
And

Finally, the resist pattern and the antireflection film pattern were removed by ashing to obtain the structure shown in FIG. 8 (i). In the ashing removal, a downflow type ashing apparatus was used, and the ashing condition was O ₂ =
500 SCCM, 800 W excitation power, 80 mTo vacuum
rr and the substrate temperature were 200 ° C.

As described above, by using the method of the present invention, even when the thickness of the antireflection film to be processed becomes large as in the process of processing the insulating film required in the dual damascene process, the film of the resist film can be formed. This is particularly effective because the antireflection film can be processed vertically without causing reduction.

The present invention has been described above by taking an antireflection film for photolithography as an example of the lower film, but the present invention is not limited to this. For example, the composition for an underlayer film of the present invention can be suitably used also as an antistatic material for preventing displacement due to charge accumulation for charged beam lithography.

[0307] In Examples 8 to 10, examples using the antistatic film are described.

Example 8 In this example, the lower layer film material solutions a) to d) prepared in Example 3 described above and the lower layer film solution material (u-1) prepared in the following manner were used. ) Was used to form a pattern as follows.

First, compound (1-1) was used as a dissolution inhibitor.
0) 9.8 g, and compound (3-4) as an acid generator
0.2 g was dissolved in cyclohexanone to prepare a solution material (u-1) for a lower layer film.

[0310] The solution material (u-
1) and the solution materials a) to lower layer film prepared in Example 3
Using d), a film to be processed and a lower layer film were sequentially formed on a silicon substrate in the same manner as in Example 3.

[0311] A TEOS oxide film to be processed was formed to a thickness of 500 nm on a silicon substrate by LPCVD. The solution material of the lower layer film was applied onto the film to be processed, and baked on a hot plate. Note that a) to d) were performed at the baking temperature shown in Table 1, and (u-1) was performed at 130 ° C. at 90 ° C.
Seconds. Thus, an antistatic film as a lower film having a thickness of 200 nm was formed.

On each antistatic film, a positive chemically amplified resist KRF M20G (manufactured by Nippon Synthetic Rubber Co., Ltd.) was applied.
Baking was performed at 140 ° C. for 90 seconds on a hot plate to form a resist film. At this time, the thickness of the resist is 200 nm.

The obtained resist film and antistatic film were subjected to pattern exposure using an electron beam at an acceleration voltage of 50 kV. The exposure amount at this time was 1.7 μC / cm ² . Thereafter, 90 ° C. at 140 ° C. using a hot plate.
By performing baking for 2 seconds, a 0.13 μm line and space latent image was formed on the resist film and the antistatic film.

Subsequently, by performing paddle development for 30 seconds with a 0.21 N aqueous solution of tetramethylammonium hydroxide to dissolve and remove the latent image formed on the resist film and the antistatic film, the resist film and the charged A 0.13 μm line and space pattern was formed on the prevention film.

When the obtained pattern was observed from above with a scanning electron microscope, it was possible to form the pattern without displacement due to charge accumulation. This is presumably because the antistatic film contained an acid generator, so that a conductive substance was generated from the acid generator by irradiating an electron beam, and the conductive substance released charges to the surroundings.

When the pattern was observed from a cross section with a scanning electron microscope, the shape of the antistatic film after the development treatment was a good vertical shape. Further, the amount of film reduction of the resist pattern after the development of the antistatic film was suppressed to 10 nm or less in any of the antistatic films. Since the thickness of the antistatic film is 200 nm, the thickness of the mask material pattern including the antistatic film pattern and the resist pattern is 390 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (TEOS oxide film) in the next step.

When the underlayer film is used as an antistatic material, it is not necessary that the underlayer film composition contains a polycyclic aromatic hydrocarbon group, as in the underlayer film solution material (u-1). Absent.

(Example 9) In this example, the material solutions a) to g) for the underlayer film prepared in Example 6 described above and the solution material for underlayer film (u-1) prepared in Example 8 were used. Was used to form a pattern as follows.

On the silicon substrate, a film to be processed and an antistatic film as a lower layer film were sequentially formed in the same procedure as in Example 6. At this time, as for (u-1), a lower layer film was formed in the same manner as in Example 8. On each of the antistatic films, the resist solution prepared in Example 2 described above was applied, respectively, and a resist film having a thickness of 200 nm was formed in the same manner as in Example 2.

An acceleration voltage of 50 was applied to the obtained resist film.
Pattern exposure was performed using a kV electron beam. The exposure amount at this time was 2.9 μC / cm ² . Thereafter, by performing baking at 110 ° C. for 90 seconds using a hot plate, a 0.13 μm line-and-space pattern latent image was formed on the resist film.

Subsequently, paddle development was performed with a 0.21 N aqueous solution of tetramethylammonium hydroxide for 30 seconds to form a line and space pattern having a diameter of 0.13 μm on the resist film.

Subsequently, the antistatic film was irradiated with an excimer lamp in the same manner as in Example 6, and then post-baked. For a) to g), the irradiation amount and the post-baking temperature shown in Table 4 were used, and for (u-1), the exposure amount was 42 mJ / cm ² and post-baking was performed at 130 ° C. for 90 seconds. As a result, the exposed portion of the antistatic film (the region not covered with the resist pattern) has a diameter of 0.13
A latent image having a contact hole pattern of μm was formed.

Finally, for a) to g), the latent image formed on the antistatic film was dissolved and removed by performing paddle development for 30 seconds with a developing solution having a specified degree shown in Table 4. A contact hole pattern having a diameter of 0.13 μm was formed on the prevention film. At this time, the solution material (u-
The antistatic film formed by using 1) was subjected to puddle development for 30 seconds using a 0.21 normal developing solution. Also in this case, the latent image formed on the antistatic film was dissolved and removed, and a contact hole pattern having a diameter of 0.13 μm was formed on the antistatic film.

When the obtained pattern was observed from above with a scanning electron microscope, it was possible to form the pattern without displacement due to charge accumulation. This is presumably because the antistatic film contained an acid generator, so that a conductive substance was generated from the acid generator by irradiating an electron beam, and the conductive substance released charges to the surroundings.

When the pattern was observed from a cross section with a scanning electron microscope, the shape of the antistatic film after the development treatment was a good vertical shape. Further, the amount of film reduction of the resist pattern after the development of the antistatic film was suppressed to 10 nm or less in any of the antistatic films. Since the thickness of the antistatic film is 200 nm, the thickness of the mask material pattern including the antistatic film pattern and the resist pattern is 390 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (TEOS oxide film) in the next step.

When the underlayer film is used as an antistatic material, it is not necessary that the underlayer film composition contains a polycyclic aromatic hydrocarbon group as in the underlayer film solution material (u-1). Absent.

(Embodiment 10) In this embodiment, the material solutions a) to g) of the antireflection film prepared in the above-mentioned embodiment 6 are used.
Was used to form a pattern as follows.

A film to be processed and an antistatic film were sequentially formed on a silicon substrate in the same procedure as in Example 6. On each antistatic film, the resist solution prepared in the above-mentioned Example 2 was applied, and the film thickness was 200 nm in the same manner as in Example 6.
Was formed.

An acceleration voltage of 50 was applied to the obtained resist film.
Pattern exposure was performed using an electron beam of kV to form a latent image of a contact hole pattern having a diameter of 0.13 μm on the resist film. At this time, the exposure amount was 5.9 μC /
cm ² . Subsequently, a stepper (N) using a reduced optical KrF excimer laser as a light source is applied to the resist film.
(A = 0.6, σ = 0.7), and a latent image of a 0.15 μm line and space pattern was formed. The light exposure at this time is 25 mJ / cm ² . Further, baking was performed at 140 ° C. for 90 seconds using a hot plate.

Thereafter, paddle development is performed for 30 seconds using an aqueous solution of 0.21 N tetramethylammonium hydroxide to dissolve and remove the latent image formed on the resist film, thereby forming a contact hole pattern and a line and space pattern. Was formed.

Subsequently, the antistatic film was irradiated with an excimer lamp in the same manner as in Example 6, and then post-baked. As a result, a latent image was formed on the exposed portion of the antistatic film (the region not covered with the resist pattern). Further, the surface of the resist pattern was crosslinked to form a surface crosslinked layer.

Finally, the resist pattern was transferred to the antistatic film by dissolving and removing the latent image formed on the antistatic film using the same method as in Example 6 and performing development processing.

When the contact hole pattern formed by the electron beam was observed from above with a scanning electron microscope, it was found that the combination of any resist film and antistatic film
A pattern could be formed without displacement due to charge accumulation. This is presumably because the antistatic film contains an acid generator, so that a conductive substance was generated from the acid generator by irradiating an electron beam, and the conductive substance released charges to the surroundings.

When the pattern was observed from a cross section with a scanning electron microscope, the lines and spaces formed by the light exposure had no wavy shape due to the standing wave, and the reflection from the underlying film was suppressed. I understand. Further, the pattern shape of the antistatic film is vertical and good.

The amount of film reduction of the resist pattern was suppressed to 10 nm or less in any of the antistatic films. Since the thickness of the antistatic film is 200 nm, the thickness of the mask material pattern including the antistatic film pattern and the resist pattern is 390 nm or more. This thickness is sufficient as a mask required for etching the film to be processed (TEOS oxide film) in the next step.

As is clear from this example, the composition for an underlayer film according to the present invention can be suitably used as an underlayer film for hybrid exposure using light and an electron beam. In this case, the lower layer film preferably contains a polycyclic aromatic hydrocarbon group in order to act as an antireflection film at the time of light exposure.

[0337]

As described in detail above, according to the present invention,
Provided is a composition for an underlayer film having a vertical side wall and capable of forming a pattern having a good rectangular cross section.

Further, according to the present invention, in a method of patterning a lower layer film, it is possible to prevent a resist pattern in an upper layer from being reduced in film thickness and to increase a pattern having vertical sidewalls and a rectangular cross section having a good shape. A pattern forming method capable of forming with high resolution and high dimensional accuracy is provided.

In particular, when the composition for an underlayer film of the present invention contains a polycyclic aromatic hydrocarbon group, even if the underlayer film is as thick as the resist film, the resist film can be reduced. It is possible to work in a vertical shape without raising.

The present invention is extremely effectively used for microfabrication for manufacturing a semiconductor device, and its industrial value is enormous.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a cross-sectional shape of a pattern obtained by a conventional pattern forming method.

FIG. 2 is a process sectional view illustrating an example of the pattern forming method of the present invention.

FIG. 3 is a process sectional view illustrating another example of the pattern forming method of the present invention.

FIG. 4 is a process sectional view showing another example of the pattern forming method of the present invention.

FIG. 5 is a process sectional view showing a conventional method of forming an antireflection film pattern.

FIG. 6 is a process sectional view illustrating a conventional method of forming an antireflection film pattern.

FIG. 7 is a process sectional view showing a conventional method of forming an antireflection film pattern.

FIG. 8 is a process sectional view illustrating another example of the pattern forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Film to be processed 2 ... Lower film 3 ... Resist film 4 ... Exposure light 5 ... Latent image formed on resist film and lower film 6 ... Film to be processed 7 ... Lower film 8 ... Resist film 9 ... Exposure light 10 ... Latent Image 11: Exposure light for irradiating the lower layer film 12: Surface cross-linked layer 13: Film to be processed 14: Lower layer film 15: Resist film 16: Exposure light 17: Latent image formed on the resist film 18: Film to be processed 19: Lower layer Film 20: resist film 21: exposure light 22: latent image formed on resist film 23: film to be processed 24: lower layer film 25: resist film 26: exposure light 27: latent image formed on resist film and lower layer film 28 ... Aluminum film 29 ... TEOS oxide film 30 ... Lower film 31 ... Resist film 32 ... Exposure light 33 ... Latent image formed on the resist film 34 ... Exposure light for irradiating the lower film 35 ... Surface cross-linked layer 36 ... Formation on the lower film Latent image 0 ... substrate 41 ... workpiece film 42 ... antireflection film 43 ... resist film 44 ... residual layer

Claims (12)

[Claims] 1. A composition for an underlayer film comprising a compound having a substituent capable of being decomposed by an acid and generating an alkali-soluble group after the decomposition, and an acid generator generating the acid. 2. A composition for an underlayer film comprising a compound having a substituent cross-linkable by an acid and an acid generator generating the acid. 3. A composition comprising a compound having a substituent capable of decomposing by an acid and generating an alkali-soluble group after decomposition, and an acid generator generating the acid, wherein the composition is a polycyclic compound. A composition for an underlayer film containing an aromatic hydrocarbon group. 4. The composition for an underlayer film according to claim 3, wherein the polycyclic aromatic hydrocarbon group has a substituent that is decomposed by the acid and is bonded to a compound that generates an alkali-soluble group after decomposition. . 5. The composition for an underlayer film according to claim 3, wherein the compound having a substituent capable of decomposing by an acid and generating an alkali-soluble group after decomposition has a structure represented by the following general formula (1). Embedded image (In the general formula (1), R ¹ and R ² may be the same or different and each is a hydrogen atom or a methyl group; R ³
Is a protecting group that is decomposed by an acid to become an alkali-soluble group;
R ⁴ is a substituted or unsubstituted polycyclic aromatic hydrocarbon group, and j and k are positive integers. ) 6. A step of forming an underlayer film on a film to be processed, a step of forming a resist film on the underlayer film, a step of pattern-exposing the resist film and the underlayer film, and a step of exposing the resist film after the exposure. And a step of developing a predetermined region of the lower film with a developing solution, wherein the lower film has a property that the solubility in the developing solution changes by the action of an acid, and the resist film and the lower film At least one of them comprises the acid-generating compound. 7. The compound according to claim 1, wherein the underlayer film has a substituent which is decomposed by an acid, and has an alkali-soluble group after decomposition.
The pattern forming method according to claim 6, wherein the pattern is formed of a composition for an underlayer film containing the acid generator that generates an acid, and an exposed portion of the underlayer film is dissolved and removed by a developer. 8. The underlayer film is formed of a composition for an underlayer film containing a compound having a substituent cross-linked by an acid and an acid generator that generates the acid, wherein an unexposed portion of the underlayer film is formed. 7. The pattern forming method according to claim 6, wherein the pattern is dissolved and removed by a developer. 9. A step of forming a lower layer film on a film to be processed, a step of forming a resist film containing a phenolic resin on the lower layer film, and pattern exposure using the first light to the resist film. Performing a developing process on the exposed resist film to form a resist pattern; irradiating the lower film with second light using the resist pattern as a mask; exposing the lower film Developing the part, wherein the underlayer film contains a compound having a substituent capable of decomposing by an acid and generating an alkali-soluble group after decomposition, and an acid generator generating the acid. A pattern forming method, comprising: a composition; wherein the composition for an underlayer film contains a polycyclic aromatic hydrocarbon group. 10. The polycyclic aromatic hydrocarbon group in the underlayer film is bonded to a compound having a substituent capable of decomposing by the acid and generating an alkali-soluble group after decomposition.
4. The pattern forming method according to 1. 11. The pattern forming method according to claim 9, further comprising the step of pattern-exposing said resist film using a charged beam. 12. A step of forming, on a film to be processed, a lower layer containing a compound having a substituent capable of being decomposed by an acid and generating an alkali-soluble group after decomposition, and an acid generator generating the acid. A step of forming a resist film containing a phenolic resin on the film, a step of pattern-exposing the resist film using a charged beam, and a step of developing the exposed resist film to form a resist pattern. A pattern forming method comprising: irradiating the lower layer film with light using the resist pattern as a mask; and developing the exposed portion of the lower layer film.