JP5282917B2 - Resist underlayer film forming composition and patterning method using the same - Google Patents

Description

  The present invention relates to a resist underlayer film forming composition for lithography and a patterning method using the composition. In particular, the present invention relates to a composition for forming a resist underlayer film covering a first mask pattern, which is applied in a second lithography process for forming a second resist pattern in so-called double patterning.

  In recent years, a lithography process called double patterning or double exposure has been studied as a method for forming a fine pattern. Double patterning is described, for example, in Patent Document 1 below. 5 to 8 of Patent Document 1 show a first lithography process for forming a first photosensitive film pattern from a first photosensitive film laminated on an organic material layer, and an organic material using the first photosensitive film pattern as a mask. Etching process for forming a layer pattern, forming a second photosensitive film covering the organic material layer pattern, and forming a second photosensitive film pattern from the second photosensitive film between two adjacent organic material layer patterns A second lithography process is shown.

  On the other hand, in the following Patent Document 2, formation of a lower layer film comprising a compound having a molecular weight of 2000 or less having at least two epoxy groups and a polymer compound having a phenolic hydroxyl group, a carboxyl group, a protected carboxyl group or an acid anhydride structure A composition is described.

However, it cannot be said that the conventional underlayer film forming composition can form a resist underlayer film having performance suitable for double patterning.
Japanese Patent No. 2803999 International Publication No. 2004/090640 Pamphlet

  The resist underlayer film is required to have a higher dry etching rate (a higher selectivity of the dry etching rate) than the resist film formed thereon.

  Further, when the resist underlayer film is applied to the second lithography process performed after the first lithography process and the etching process of double patterning, it is possible to sufficiently cover (embed) the step due to the mask pattern formed by the etching process. A resist underlayer film is required. More preferably, the resist underlayer film covering the step is required to have a flat surface. In addition, the composition needs to have solubility in a predetermined solvent so that a resist underlayer film can be formed by a coating method.

  Furthermore, it is required that the refractive index (n value) and the extinction coefficient (also referred to as k value or attenuation coefficient) for short wavelength light such as ArF excimer laser show desired values. It is an object of the present invention to provide a composition for forming a resist underlayer film that satisfies such required characteristics.

  The composition according to the present invention comprises a compound obtained by reacting a triepoxy compound, an acid anhydride which may have a substituent, and an alcohol compound (solvent), the terminal of which is substituted with the alcohol compound. It is characterized by doing.

  Presence of a compound represented by the formula (4), a compound represented by the formula (1), or an acid anhydride represented by the formula (2) and a compound represented by the formula (3) described later. By using the resist underlayer film forming composition according to the present invention containing a product obtained by reacting under the above, it is possible to form a resist underlayer film having a high dry etching rate selectivity with respect to the resist film.

  Since the compound represented by the above formula (1) or the product is excellent in solubility in a solvent containing an organic solvent having a hydroxy group as a main component, the resist underlayer film forming composition according to the present invention is applied by a coating method. Thus, it is possible to easily form a resist underlayer film.

  The resist underlayer film forming composition according to the present invention covers (embeds) a step, and the resist underlayer film formed therefrom has a relatively flat surface. This resist underlayer film can be preferably applied to the second lithography process of double patterning.

  By using the resist underlayer film forming composition according to the present invention, a resist underlayer film having a high refractive index (n value) exceeding 1.6 and a relatively small extinction coefficient k value for light having a wavelength of 193 nm Is obtained.

The result of having observed the cross-sectional shape of the photoresist pattern by SEM is shown. The result of having observed the cross section of the sample which evaluates level | step difference coverage with SEM is shown.

The present invention provides the following formula (1):
(In the formula, A _{1 to} A ₉ each independently represents a hydrogen atom, a methyl group or an ethyl group, and each R ₁ independently represents at least one halogen atom selected from a bromine atom and a chlorine atom. An aromatic structure as a group, an alicyclic structure that may have at least one substituent, or an aliphatic structure that may have at least one substituent, each R ₂ has 1 to 3 carbon atoms A compound containing a compound having a hydroxy group and an organic solvent having a hydroxy group as a main component and a crosslinking agent. The present invention relates to a resist underlayer film forming composition.

Examples of the compound contained in the resist underlayer film forming composition according to the present invention include at least one acid anhydride represented by the following formula (2) and a compound represented by the following formula (3):
(Wherein A _{1 to} A ₉ each independently represents a hydrogen atom, a methyl group or an ethyl group, and R ₁ is an aromatic having at least one halogen atom selected from a bromine atom and a chlorine atom as a substituent. Represents an aliphatic structure which may have at least one group structure, an alicyclic structure which may have at least one substituent, or an aliphatic structure which may have at least one substituent.
(Wherein R ₂ represents a hydrocarbon group having 1 to 6 carbon atoms which may have an alkoxy group having 1 to 3 carbon atoms as a substituent) of at least one compound represented by It is a product obtained by reacting in the presence.

Examples of the aromatic structure representing R ₁ include a structure containing a benzene ring, a naphthalene ring and an anthracene ring, and examples of the alicyclic structure representing R ₁ include a cyclobutane ring, a cyclohexane ring or a cyclohexene ring. Examples of the aliphatic structure representing R ₁ include structures having a double bond or a single bond between the two carbon atoms, such as an ethylene group and a vinylene group.

Furthermore, as the substituent which the aromatic structure representing said R ₁ has, for example, a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a chlorine atom and a bromine atom are preferable. By using an aromatic structure having a halogen atom as the structure representing R ₁ , the dry etching rate is remarkably improved as compared with an aromatic structure having no halogen atom.
Examples of the substituent that the alicyclic structure and the aliphatic structure representing R ₁ may have include at least one halogen atom and an acetyloxy group (acetoxy group). As the halogen atom, a bromine atom is preferable.

Examples of the hydrocarbon group having 1 to 6 carbon atoms representing R ₂ include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group. However, it is not limited to the alkyl group.
Examples of the alkoxy group having 1 to 3 carbon atoms of the hydrocarbon group include a methoxy group, an ethoxy group, a propoxy group, and an i-propoxy group.

  When the acid anhydride represented by the formula (2) and the compound represented by the formula (3) are reacted in the presence of the compound represented by the formula (4), a catalyst or a radical polymerization inhibitor is optionally used. Etc. can be used. Examples of the catalyst include quaternary ammonium salts and quaternary phosphonium salts. Substances known as quaternary ammonium salts and quaternary phosphonium salts can be used. Examples of the acid anhydride represented by the formula (2) include succinic anhydride, maleic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, phthalic anhydride, and (+)-diacetyl-L. -Tartaric acid anhydride, tartaric acid anhydride are mentioned, but are not limited to these acid anhydrides. Examples of the compound represented by the formula (3) include, but are not limited to, tris- (2,3-epoxypropyl) -isocyanurate. Examples of the compound represented by the formula (4) include, but are not limited to, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethanol, 1-propanol, isopropanol, and 1-butanol.

  The reaction conditions depend on the compounds used and their concentrations and are not particularly limited. For example, the reaction conditions are appropriately selected from a reaction temperature range of 100 ° C. to 150 ° C. and a reaction time of 1 hour to 24 hours.

  The weight average molecular weight of the compound represented by the formula (1) or the product is, for example, 500 to 2000.

  In the resist underlayer film forming composition according to the present invention, the compounding amount of the compound represented by the formula (1) or the product is, for example, 1% by mass to 5% by mass with respect to the total mass of the composition.

  In the solvent mainly containing an organic solvent having a hydroxy group, which is contained in the resist underlayer film forming composition according to the present invention, examples of the organic solvent having a hydroxy group include propylene glycol monomethyl ether and 4-methyl-2-pentanol. However, it is not limited to these. In the present specification, “main component” means that the organic solvent having a hydroxy group is contained in the solvent in a proportion exceeding 50 mass%. The solvent may contain an organic solvent having no hydroxy group, such as propylene glycol monomethyl ether acetate, as a subsidiary component.

  The content of the solvent is appropriately selected and is, for example, 90% by mass to 99% by mass with respect to the total mass of the resist underlayer film forming composition.

  Examples of the crosslinking agent contained in the resist underlayer film forming composition according to the present invention include compounds having 2 to 4 nitrogen atoms bonded to a methylol group or an alkoxymethyl group in one molecule. Examples of such a crosslinking agent include hexamethoxymethyl melamine, tetramethoxymethyl benzoguanamine, 1,3,4,6-tetrakis (methoxymethyl) glycoluril, 1,3,4,6-tetrakis (butoxymethyl) glycoluril, 1,3,4,6-tetrakis (hydroxymethyl) glycoluril, 1,3-bis (hydroxymethyl) urea, 1,1,3,3-tetrakis (butoxymethyl) urea and 1,1,3,3- Tetrakis (methoxymethyl) urea is mentioned.

  In the resist underlayer film forming composition according to the present invention, the content of the crosslinking agent depends on the compound represented by the formula (1) or the product and the solvent to be used, the viscosity of the required solution, and the film shape. Although it should be set to a suitable range as appropriate, for example, in a ratio of 1% by mass to 30% by mass, or 15% by mass to 30% by mass with respect to the compound represented by the formula (1) or the product. Can be contained. If it is less than 1% by mass, the resist underlayer film may not be sufficiently cured.

  The resist underlayer film forming composition according to the present invention may further contain a sulfonic acid compound. A sulfonic acid compound can be added to the compound represented by the formula (1) or the product in a proportion of, for example, 0.1% by mass to 10% by mass, or 1% by mass to 5% by mass. Examples of sulfonic acid compounds include p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium-p-toluenesulfonic acid, camphorsulfonic acid, 5-sulfosalicylic acid, 4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, and benzenedisulfonic acid. 1-naphthalenesulfonic acid and pyridinium-1-naphthalenesulfonic acid.

  The resist underlayer film forming composition according to the present invention may further contain a surfactant. By adding the surfactant, the coating property of the resist underlayer film forming composition on the substrate can be improved. A known surfactant such as a nonionic surfactant or a fluorine-based surfactant can be used, and a ratio of, for example, 0.01% by mass to 2.0% by mass with respect to the resist underlayer film forming composition according to the present invention. Can be added.

The resist underlayer film forming composition according to the present invention comprises a resist underlayer film that covers (embeds) a step of a substrate or a step of a first pattern formed on the substrate by a coating method and has a relatively flat surface. can get. In addition, the obtained resist underlayer film has a high selectivity ratio with respect to the resist film and a desired refractive index (n value) and extinction coefficient (k value) with respect to the exposure light used in the lithography process. .
By having a high selection ratio of the dry etching rate, it is possible to suppress a decrease in the thickness of the resist film during dry etching of the resist underlayer film. When the selection ratio of the dry etching rate is small, there arises a problem that the thickness of the resist film becomes thin during dry etching of the resist underlayer film, and a fine pattern cannot be formed.
By having a desired refractive index (n value) and extinction coefficient (k value), the resist underlayer film prevents the reflected light from the substrate from reaching the resist film during exposure. These desired values vary depending on the intended use and the thickness of the resist underlayer film. If the refractive index (n value) and extinction coefficient (k value) are not desired values, the resist underlayer film cannot suppress the reflected light from the substrate during exposure, and a fine pattern cannot be formed.

  The present invention also includes a step of applying and covering the resist underlayer film forming composition for lithography on the first pattern formed on or above the semiconductor substrate, and baking the applied composition to form a resist underlayer. A step of forming a film, a step of forming a resist film on the resist underlayer film, and then forming a second pattern by at least exposing and developing the resist film; and using the second pattern as a mask The present invention relates to a patterning method including a step of etching the resist underlayer film and exposing the first pattern. For example, the second pattern is formed so as not to overlap the first pattern. The temperature at the time of baking is, for example, 160 ° C. to 300 ° C.

  Hereinafter, the present invention will be specifically described with reference to synthesis examples and examples. However, the present invention is not limited to the description of the following synthesis examples and examples.

The weight average molecular weight of the compound obtained in the following synthesis example is a measurement result by gel permeation chromatography (hereinafter abbreviated as GPC). The measurement conditions etc. are as follows using the Tosoh Co., Ltd. product GPC apparatus for a measurement.
GPC column: Shodex (registered trademark) and Asahipak (registered trademark) (Showa Denko KK)
Column temperature: 40 ° C
Solvent: N, N-dimethylformamide (DMF)
Flow rate: 0.6 ml / min Standard sample: Polystyrene (Tosoh Corporation)

<Synthesis Example 1>
Tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC [registered trademark]) 5.00 g, succinic anhydride (Tokyo Chemical Industry Co., Ltd.) 5.01 g , And 0.47 g of quaternary phosphonium salt triphenylmonoethylphosphonium bromide as a catalyst was dissolved in 24.45 g of propylene glycol monomethyl ether, heated to 120 ° C., and stirred under a nitrogen atmosphere for 4 hours. When the GPC analysis of the varnish solution diluted with 17.46 g of propylene glycol monomethyl ethers was conducted, the weight average molecular weight was 1266 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (5).

<Synthesis Example 2>
Tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC (registered trademark)) 2.50 g, tetrabromophthalic anhydride (Tokyo Chemical Industry Co., Ltd.) 11 .62 g and 0.23 g of quaternary phosphonium salt triphenylmonoethylphosphonium bromide as a catalyst were dissolved in 33.48 g of propylene glycol monomethyl ether, heated to 120 ° C., and stirred for 4 hours in a nitrogen atmosphere. did. When the GPC analysis of the varnish solution diluted with 23.91 g of propylene glycol monomethyl ethers was performed, the weight average molecular weight was 1491 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (6).

<Synthesis Example 3>
Tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC [registered trademark]) 5.00 g, maleic anhydride (Tokyo Chemical Industry Co., Ltd.) 4.91 g, After dissolving 0.07 g of hydroquinone (Tokyo Kasei Kogyo Co., Ltd.) as a radical polymerization inhibitor and 0.47 g of triphenyl monoethylphosphonium bromide which is a quaternary phosphonium salt as a catalyst in 24.38 g of propylene glycol monomethyl ether The mixture was heated to 120 ° C. and stirred for 4 hours under a nitrogen atmosphere. When the GPC analysis of the varnish solution diluted with 27.18 g of propylene glycol monomethyl ethers was performed, the weight average molecular weight was 1224 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (7).

<Synthesis Example 4>
Tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC [registered trademark]) 2.50 g, tetrachlorophthalic anhydride (Tokyo Chemical Industry Co., Ltd.) 7 .16 g and quaternary phosphonium salt triphenylmonoethylphosphonium bromide 0.23 g as a catalyst were dissolved in 23.09 g of propylene glycol monomethyl ether, heated to 120 ° C., and stirred for 4 hours in a nitrogen atmosphere. did. When the GPC analysis of the varnish solution diluted with 16.49 g of propylene glycol monomethyl ethers was conducted, the weight average molecular weight was 1415 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (8).

<Synthesis Example 5>
5.79 g of tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC [registered trademark]), and (+)-diacetyl-L-tartaric anhydride (Tokyo Kasei) After dissolving 4.21 g of Kogyo Co., Ltd. in 9.667 g of propylene glycol monomethyl ether, the mixture was heated to 120 ° C. and stirred for 3 hours under a nitrogen atmosphere. In this synthesis example, no catalyst is used because of its high reactivity. When the GPC analysis of the varnish solution diluted with 30 g of propylene glycol monomethyl ether was performed, the weight average molecular weight was 1197 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (9).

<Synthesis Example 6>
Tetrabromophthalic anhydride (Tokyo Chemical Industry Co., Ltd.) 6.20 g and quaternary ammonium salt benzyltriethylammonium chloride 0.11 g as a catalyst were dissolved in isopropanol 7.89 g, and then heated to 120 ° C. Warmed and stirred for 4 hours under nitrogen atmosphere. Residual isopropanol was removed from the solution with an evaporator, and the resulting substance and tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC (registered trademark)) After 1.79 g was dissolved in 7.89 g of propylene glycol monomethyl ether, the mixture was heated again to 120 ° C. and stirred for 24 hours under a nitrogen atmosphere. When the GPC analysis of the varnish solution diluted with 24.00 g of propylene glycol monomethyl ether was performed, the weight average molecular weight was 920 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (10).

<Synthesis Example 7>
After dissolving 6.20 g of tetrabromophthalic anhydride (Tokyo Chemical Industry Co., Ltd.) and 0.11 g of benzyltriethylammonium chloride which is a quaternary ammonium salt as a catalyst in 7.89 g of 1-butanol, 120 ° C. And stirred for 4 hours under a nitrogen atmosphere. Residual 1-butanol was removed from this solution with an evaporator, and the resulting substance and tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC (registered trademark)) ) 1.79 g was dissolved in 7.89 g of propylene glycol monomethyl ether, then heated again to 120 ° C. and stirred for 24 hours under a nitrogen atmosphere. When GPC analysis of the varnish solution diluted with 24.00 g of propylene glycol monomethyl ether was performed, the weight average molecular weight was 1223 in terms of standard polystyrene. This reaction product has a structure represented by the following formula (11).

<Synthesis Example 8>
6.20 g of tetrabromophthalic anhydride (Tokyo Chemical Industry Co., Ltd.) and 0.11 g of benzyltriethylammonium chloride as a catalyst were dissolved in 7.89 g of ethylene glycol monomethyl ether, and then heated to 120 ° C. Stir for 4 hours under atmosphere. Residual ethylene glycol monomethyl ether was removed from this solution with an evaporator, and the resulting material and tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC [registered trademark] ] 1.79 g was dissolved in 7.89 g of propylene glycol monomethyl ether, and then heated again to 120 ° C. and stirred for 24 hours under a nitrogen atmosphere. When the GPC analysis of the varnish solution diluted with 24.00 g of propylene glycol monomethyl ether was performed, the weight average molecular weight was 1449 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (12).

<Synthesis Example 9>
7.42 g of phthalic anhydride (Tokyo Chemical Industry Co., Ltd.) and 0.47 g of quaternary phosphonium salt triphenylmonoethylphosphonium bromide as a catalyst were dissolved in 12.89 g of ethanol, and then heated to 120 ° C. Warmed and stirred for 4 hours under nitrogen atmosphere. Ethanol remaining from the solution was removed by an evaporator, and 5.00 g of tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC [registered trademark]), propylene glycol After dissolving in 12.89 g of monomethyl ether, the mixture was heated again to 120 ° C. and stirred for 24 hours under a nitrogen atmosphere. When the GPC analysis of the varnish solution diluted with 38.66 g of propylene glycol monomethyl ether was performed, the weight average molecular weight was 870 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (13). The acid anhydride used in this synthesis example has no substituent.

<Synthesis Example 10>
Tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, trade name: TEPIC [registered trademark]) 5.00 g, phthalic anhydride (Tokyo Chemical Industry Co., Ltd.) 7.42 g , And 0.47 g of quaternary phosphonium salt triphenylmonoethylphosphonium bromide as a catalyst was dissolved in 12.89 g of propylene glycol monomethyl ether, heated to 120 ° C., and stirred under a nitrogen atmosphere for 24 hours. When the GPC analysis of the varnish solution diluted with 38.66 g of propylene glycol monomethyl ether was performed, the weight average molecular weight was 1260 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (14). The acid anhydride used in this synthesis example is the same as synthesis example 9.

<Synthesis Example 11>
5.00 g of tris- (2,3-epoxypropyl) -isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name: TEPIC [registered trademark]), 6.12 g of benzoic acid (Tokyo Chemical Industry Co., Ltd.), and As a catalyst, 0.47 g of quaternary phosphonium salt, triphenylmonoethylphosphonium bromide, was dissolved in 11.58 g of propylene glycol monomethyl ether, heated to 120 ° C., and stirred for 24 hours in a nitrogen atmosphere. When the GPC analysis of the varnish solution diluted with 16.34 g of propylene glycol monomethyl ethers was conducted, the weight average molecular weight was 616 in standard polystyrene conversion. This reaction product has a structure represented by the following formula (15).

[Example 1]
To 4.2351 g of the solution containing 0.927 g of the reaction product obtained in Synthesis Example 1, 22.612 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries Co., Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.232 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.] ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

[Example 2]
To 5.332 g of the solution containing 0.927 g of the reaction product obtained in Synthesis Example 2, 21.515 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries Co., Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.232 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.] ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

Example 3
To 4.596 g of a solution containing 0.927 g of the reaction product obtained in Synthesis Example 3, 22.250 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries, Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.232 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.] ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

Example 4
To 5.004 g of a solution containing 0.927 g of the reaction product obtained in Synthesis Example 4, 21.443 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries, Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.232 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.] ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

Example 5
To 5.3480 g of the solution containing 0.938 g of the reaction product obtained in Synthesis Example 5, 12.5095 g of propylene glycol monomethyl ether, 1.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries, Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.2344 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.) ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

Example 6
To a solution (5.4798 g) containing 0.927 g of the reaction product obtained in Synthesis Example 6, 21.3668 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries Co., Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.2317 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.) ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

Example 7
To 5.5355 g of a solution containing 0.927 g of the reaction product obtained in Synthesis Example 7, 21.3112 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries, Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.2317 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.) ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

Example 8
To 5.1884 g of the solution containing 0.927 g of the reaction product obtained in Synthesis Example 8, 21.5883 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries, Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.2317 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.) ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

[Reference Example 1]
To 5.001 g of the solution containing 0.927 g of the reaction product obtained in Synthesis Example 9, 21.646 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries, Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.232 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.] ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

[Reference Example 2]
To 4.560 g of a solution containing 0.927 g of the reaction product obtained in Synthesis Example 10, 22.286 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries Co., Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.232 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.] ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

[Comparative Example 1]
To 6.435 g of a solution containing 0.927 g of the reaction product obtained in Synthesis Example 11, 20.41 g of propylene glycol monomethyl ether, 2.880 g of propylene glycol monomethyl ether acetate, tetramethoxymethyl glycoluril (Nippon Cytec Industries Co., Ltd.) , Trade name: POWDERLINK (registered trademark) 1174) 0.232 g, p-phenolsulfonic acid (Tokyo Chemical Industry Co., Ltd.) 0.023 g, and surfactant (DIC Corporation [former Dainippon Ink & Chemicals, Inc.] ], Trade name: MegaFac R-30) 0.019 g was added to make a solution. Then, it filtered using the polyethylene micro filter with a hole diameter of 0.10 micrometer, and prepared the resist lower layer film forming composition.

(Optical parameter test)
The resist underlayer film forming compositions prepared in Examples 1 to 8, Reference Examples 1 and 2, and Comparative Example 1 described in this specification were each applied onto a silicon wafer by a spinner. Baking was carried out at 205 ° C. for 1 minute on a hot plate to form a resist underlayer film (film thickness 0.06 μm). Then, these resist underlayer films were subjected to a spectroscopic ellipsometer (manufactured by JA Woollam, VUV-VASE VU-302) using an n value (refractive index) and a k value (attenuation coefficient or extinction coefficient) for light having a wavelength of 193 nm ) Was measured. The results are shown in Table 1.

(Measurement of dry etching rate)
The resist underlayer film forming compositions prepared in Examples 1 to 8, Reference Examples 1 and 2, and Comparative Example 1 described in this specification were each applied onto a silicon wafer by a spinner. Baking was performed at 205 ° C. for 1 minute on a hot plate to form a resist underlayer film. The dry etching rate (reduction in film thickness per unit time) was measured using RIE system ES401 manufactured by Nippon Scientific Co., Ltd. under the condition of using CF ₄ as the dry etching gas.

A photoresist solution (manufactured by Sumitomo Chemical Co., Ltd., trade name: PAR710) was applied onto a silicon wafer by a spinner and baked on a hot plate at 90 ° C. for 1 minute to form a photoresist film. The dry etching rate was measured using RIE system ES401 manufactured by Nippon Scientific Co., Ltd. under the condition that CF ₄ was used as the dry etching gas.

  The dry etching rate of the resist underlayer film obtained from the resist underlayer film forming composition prepared in Examples 1 to 8, Reference Examples 1 and 2 and Comparative Example 1 described in the present specification, Sumitomo Chemical Co., Ltd. Comparison was made with the dry etching rate of a photoresist film formed from a photoresist solution (PAR710). Table 1 shows the dry etching rate of the resist underlayer film obtained from the resist underlayer film forming composition of each Example and Comparative Example when the dry etching rate of the photoresist film is 1.00. ".

  The results shown in Table 1 show that the resist underlayer films obtained from the resist underlayer film forming compositions of Examples 1 to 8 have sufficient n and k values for light with a wavelength of 193 nm. Further, it can be seen that the resist underlayer film obtained from the resist underlayer film forming composition of the present invention has a remarkably large dry etching rate selectivity with respect to conventionally used photoresists. Accordingly, it is possible to suppress a decrease in the film thickness of the photoresist film accompanying the removal of the resist underlayer film by dry etching.

  On the other hand, the resist underlayer film obtained from the resist underlayer film forming composition prepared in Comparative Example 1 has a k value that is higher than a desired value, compared to any resist underlayer film obtained from the resist underlayer film forming composition of the present invention. It is large and it is difficult to reduce the reflected light from the silicon substrate. In addition, the resist underlayer film obtained from the resist underlayer film forming composition prepared in Comparative Example 1 has a dry etching rate selectivity ratio higher than any resist underlayer film obtained from the resist underlayer film forming composition of the present invention. small.

(Evaluation of photoresist pattern shape)
The resist underlayer film forming composition prepared in Example 2 was applied by a spinner onto a substrate on which a SiON film (nitrogen-containing silicon oxide film) was deposited to a thickness of 0.05 μm on a silicon wafer. Then, baking was performed at 205 ° C. for 1 minute on a hot plate to form a resist underlayer film having a thickness of 20 to 30 nm. A commercially available photoresist solution (trade name: PAR855, manufactured by Sumitomo Chemical Co., Ltd.) was applied onto the resist underlayer film by a spinner, and baked on a hot plate at 115 ° C. for 60 seconds to form a photoresist film ( A film thickness of 0.12 μm) was formed.

  Next, using a Nikon scanner, NSRS307E (wavelength 193 nm, NA: 0.85, σ: 0.65 / 0.93 (ANNNULAR)), after development, the line width of the photoresist and between the lines of the photoresist The width of each is 0.08 μm, that is, 0.08 μmL / S (dense line), and exposure is performed at a predetermined exposure amount through a photomask set so that nine such lines are formed. Went. Thereafter, after exposure (PEB) is performed on a hot plate at 105 ° C. for 60 seconds, and after cooling, a 0.26N aqueous tetramethylammonium hydroxide solution is used as a developer in an industrial standard 60-second single paddle process. And developed.

  About the obtained photoresist pattern, the cross section of the board | substrate, ie, a silicon wafer, and the orthogonal | vertical direction was observed with the scanning electron microscope (SEM). As a result, it was observed that the cross-sectional shape of the obtained photoresist pattern was a straight skirt shape as shown in FIG. FIG. 1B shows the result of changing the photoresist solution to that of another company (Shin-Etsu Chemical Co., Ltd.) and observing the cross-sectional shape of the obtained photoresist pattern with SEM in the same manner as described above.

(Evaluation of step coverage)
The resist underlayer film forming composition prepared in Example 2 was applied onto a stepped substrate by a spinner under the condition of a rotational speed of 1500 rpm. The stepped substrate used was obtained from Advantech Co., Ltd., the step height was 80 nm, the L / S (line and space) was 100 nm / 300 nm, and the substrate was formed with a silicon oxide film. Thereafter, the cross section of the sample baked at 205 ° C. for 60 seconds was observed with a scanning electron microscope (SEM). FIG. 2A shows a cross-sectional SEM image of the stepped substrate, and FIG. 2B shows a cross-sectional SEM image of a sample in which the resist underlayer film is formed so as to cover the stepped substrate. From FIG. 2 (B), it was observed that the resist underlayer film forming composition prepared in Example 2 was excellent in the embedding property of the step of the substrate and had relatively good flatness.

Claims (12)

Following formula (1):
Wherein A1 to A9 each independently represents a hydrogen atom, a methyl group or an ethyl group, and each R1 independently represents an aromatic structure having at least one halogen atom selected from a bromine atom and a chlorine atom. Represents an alicyclic structure which may have at least one substituent or an aliphatic structure which may have at least one substituent, and each R 2 has an alkoxy group having 1 to 3 carbon atoms as a substituent. Representing a hydrocarbon group having 1 to 6 carbon atoms that may be present.), A resist underlayer film forming composition for lithography, comprising: a compound represented by: an organic solvent having a hydroxy group as a main component; and a crosslinking agent. . At least one acid anhydride represented by the following formula (2) and a compound represented by the following formula (3):
(Wherein A _{1 to} A ₉ each independently represents a hydrogen atom, a methyl group or an ethyl group, and R ₁ is an aromatic having at least one halogen atom selected from a bromine atom and a chlorine atom as a substituent. Represents an aliphatic structure which may have an aliphatic structure which may have at least one group structure, an alicyclic structure which may have at least one substituent.)
With the following formula (4):
(Wherein R ₂ represents a hydrocarbon group having 1 to 6 carbon atoms which may have an alkoxy group having 1 to 3 carbon atoms as a substituent) of at least one compound represented by A resist underlayer film forming composition for lithography comprising a product obtained by reacting in the presence, a solvent mainly comprising an organic solvent having a hydroxy group, and a crosslinking agent.   The resist underlayer film forming composition for lithography according to claim 1, wherein the aromatic structure is a structure containing a benzene ring.   The resist underlayer film forming composition for lithography according to claim 1 or 2, wherein the aliphatic structure is a structure containing a double bond or a single bond between the two carbon atoms.   The resist underlayer film forming composition for lithography according to claim 1, wherein the substituent that the alicyclic structure and the aliphatic structure may have is at least one halogen atom. object.   6. The resist underlayer film forming composition for lithography according to claim 5, wherein the halogen atom is a bromine atom.   The resist underlayer film forming composition for lithography according to any one of claims 1 to 4, wherein the substituent that the alicyclic structure and the aliphatic structure may have is an acetyloxy group.   3. The resist underlayer film forming composition for lithography according to claim 1, wherein the hydrocarbon group is an alkyl group having 1 to 4 carbon atoms.   9. The resist underlayer film formation for lithography according to claim 1, wherein the crosslinking agent is a compound having 2 to 4 nitrogen atoms bonded to a methylol group or an alkoxymethyl group in one molecule. Composition.   The resist underlayer film forming composition for lithography according to any one of claims 1 to 9, further comprising a sulfonic acid compound and / or a surfactant.   The process of apply | coating and coat | covering the resist underlayer film forming composition for lithography as described in any one of Claim 1 thru | or 10 on the 1st pattern formed on the semiconductor substrate or its upper direction, The said resist Baking the underlayer film forming composition to form a resist underlayer film, forming a resist film on the resist underlayer film, and then performing at least exposure and development on the resist film to form a second pattern A patterning method including: a step; and a step of etching the resist underlayer film using the second pattern as a mask and exposing the first pattern.   The patterning method according to claim 11, wherein the second pattern is formed so as not to overlap the first pattern.