JP5141554B2 - PATTERN FORMING METHOD AND HIGH CARBON-CONTAINING RESIN COMPOSITION - Google Patents

Description

  The present invention relates to a pattern formation method used in a lithography process in a semiconductor manufacturing process and a high carbon-containing resin composition suitable for the pattern formation method, and in particular, a copolymer of hydroxymethylacenaphthylene and / or a hydroxymethylstyrene copolymer. The present invention relates to a high carbon content resin composition containing a polymer as a resin component.

  Lithographic processes are used in the field of integrated circuit device manufacturing. In this lithography process, a resist composition is applied as a solution on a substrate, a mask pattern is transferred by a reduction projection exposure apparatus (stepper), and developed with an appropriate developer to obtain a desired pattern. In order to obtain a higher degree of integration, the processing size has been miniaturized using an ArF laser in the lithography process. However, since a resist used in a lithography process using an ArF laser is required to be almost transparent at an ArF wavelength, polyacrylic acid ester or polymethacrylic acid ester having poor etching resistance is generally used. Furthermore, in order to prevent pattern collapse, it is necessary to reduce the resist thickness as the processing size is reduced. By using an ArF resist having poor etching resistance as a thin film, there is a problem that a fine resist pattern cannot be accurately transferred to a substrate to be processed.

In order to solve this problem, there has been proposed a pattern transfer process in which a mask film is provided under a resist film to be formed on a substrate (between the substrate and the resist film). Such a process is generally called a multilayer resist process, and a two-layer resist process or a three-layer resist process is well known. Such a multilayer resist process has disadvantages such as an increase in manufacturing cost and a reduction in processing capability because a step of providing a mask film under the resist film and a step of processing the mask film are added.
In order to solve the disadvantages of the multilayer resist process, a pattern inversion process using a compound containing silicone or metal has been proposed (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

However, the pattern reversal process using a compound containing silicone or metal, when mixed even slightly with a resist film containing silicone or metal (intermixing), greatly reduces the etching characteristics, and thus causes processing defects when processing a substrate to be processed. May cause. For example, since silicone cannot be completely removed by etching or the like, there is a problem that needle-like residues remain on the organic film and impair the reliability of the product (see Non-Patent Document 1). Further, it is known that a material using a polymer having a higher carbon content is superior in etching resistance under ion etching conditions (see Non-Patent Document 2).
Therefore, it is desired to develop an improved pattern forming method and a polymer particularly useful as a polymer component used in the pattern forming method, which can solve various problems related to the lithography process.
JP 2004-335873 A JP 2002-110510 A JP 2001-343757 A Changing Behavior of Residue during Dry Etching in Multilayer Resist Process by Keiji Watanabe et al., Journal of Photopolymer Science and Technology page 157-163 Vol 18, No 1,2005 Dry Etch Resistance of Organic Materials by Y. Ohnishi et al., Journal of the electrochemical society page 143-146 Vol 130, No 1,1983

  The present invention has been made to cope with such problems, and in a lithography process, a pattern forming method for forming a pattern having sufficient etching resistance under conditions for etching a substrate to be processed, and the pattern forming method. An object of the present invention is to provide a high carbon-containing resin composition. It is another object of the present invention to provide a dual damascene structure forming method and a suitable polymer used in this structure forming method, regardless of the type of substrate to be processed.

The pattern forming method of the present invention comprises a step of forming a resist pattern on a substrate to be processed, and a polymer and a solvent having a carbon content higher than that of the resist pattern and not containing silicon atoms in the molecule between the resist patterns. It includes a step of embedding and heating a high carbon-containing resin composition, and a step of removing only the resist pattern to form a pattern of the polymer on the substrate to be processed.
Further, the carbon content of the high carbon-containing resin composition is 80% by mass or more.
In addition, a radiation irradiation treatment is performed after the step of embedding the resin composition.
Further, the pattern forming method is a dual damascene structure forming method.

In the present invention, “the carbon content is higher than that of the resist pattern” means that the polymer constituting the resist film has a high carbon atom content (% by mass) in the polymer molecule.
For example, the carbon content in the repeating unit derived from acrylic acid [— (CH ₂ —CH (COOH) —]) is calculated by (12 × 3 × 100) / (12 × 3 + 1 × 4 + 16 × 2), and is 50% by mass. In contrast, the carbon content in the repeating unit derived from styrene [— (CH ₂ —CH (C ₆ H ₆ ) —] is calculated by (12 × 8 × 100) / (12 × 8 + 1 × 9). For this reason, the repeating unit containing an aromatic ring has a high carbon content.

式（１）において、Ｒ¹およびＲ²は、水素原子、炭素数１〜３のアルキル基、またはアリール基を表し、Ｒ³は、炭素数１〜３のアルキル基、ビニル基、アリル基、またはアリール基を表し、ｎは０または１、ｍは０、１または２を表す。特に、上記繰返し単位における、Ｒ¹およびＲ²が水素原子、ｎおよびｍが０であることを特徴とする。
また、高炭素含有樹脂組成物を構成する溶剤は、アルコール類およびエーテル類から選ばれた少なくとも１つの溶剤を含むことを特徴とする。The high carbon-containing resin composition of the present invention is a high carbon-containing resin composition used in the pattern forming method, wherein the polymer constituting the resin composition includes a repeating unit containing an aromatic ring in the molecule. It is characterized by that.
In the high carbon-containing resin composition, the repeating unit containing an aromatic ring in the molecule includes at least one repeating unit selected from the repeating units represented by the following formula (1) and the following formula (2), The polymer is characterized by having a polystyrene-reduced mass average molecular weight of 500 to 500,000 measured by gel permeation chromatography.

In Formula (1), R ¹ and R ² represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an aryl group, and R ³ represents an alkyl group having 1 to 3 carbon atoms, a vinyl group, an allyl group, Or an aryl group, n represents 0 or 1, and m represents 0, 1 or 2. In particular, R ¹ and R ² in the above repeating unit are hydrogen atoms, and n and m are 0.
Further, the solvent constituting the high carbon content resin composition contains at least one solvent selected from alcohols and ethers.

According to the pattern forming method of the present invention, in a lithography process, a pattern having sufficient etching resistance can be formed under conditions for etching a substrate to be processed, and a multilayer applied when using a resist pattern having poor etching resistance. The substrate to be processed can be etched by a so-called single-layer resist process that does not involve an increase in manufacturing cost and a decrease in processing capacity, which are disadvantages of the resist process. Moreover, since this invention does not ask | require a to-be-processed substrate kind, it is suitable for dual damascene structure formation. The polymer used in the pattern forming method of the present invention has a high carbon content. For this reason, it is excellent in etching resistance under ion etching conditions.
In the resist pattern forming method of the present invention, a polymer pattern having a high carbon content can be formed on a substrate to be processed. Therefore, the resist pattern is excellent in etching resistance and has a sufficient mask performance when etching a substrate to be processed.

  The pattern forming method of the present invention will be described with reference to FIGS. 1 to 3 are process diagrams of a pattern forming method. 1 to 3, for example, FIG. 1 (d), FIG. 2 (d), and FIG. 3 (d) indicate the same state. Further, the present invention is not limited to the following embodiments, and it is understood that design changes, improvements, and the like can be added as appropriate based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be.

(1) Step of forming a resist pattern on a substrate to be processed A pattern forming resin composition solution for ArF having a polyacrylate or polymethacrylate structure is spin-coated on a silicon wafer 1 having a diameter of 8 inches. A resist film 2a having a thickness of 200 nm is formed by pre-baking on a hot plate at ˜130 ° C. for 30 to 90 seconds (FIG. 1A). In addition, after forming an oxide layer, a conductive layer, an antireflection film or the like on the silicon wafer 1, the resist film 2 may be formed on the antireflection film. After the antireflection film forming composition is spin-coated on the wafer 1, it can be formed by heating on a hot plate at 100 to 200 ° C. for 60 to 120 seconds. The film thickness of the antireflection film is a film thickness that minimizes the reflectance from the substrate, and varies depending on the product, but is generally 30 to 60 nm.
The silicon wafer 1 on which the resist film 2a is formed is exposed for an optimum exposure time through a mask pattern using an ArF excimer laser exposure apparatus manufactured by NIKON. Then, after post-baking on a hot plate at 100 to 130 ° C. for 60 to 120 seconds, using a 2.38 mass% aqueous tetramethylammonium hydroxide solution, developing at 25 ° C. for 30 to 120 seconds, washing with water, and drying Then, a positive ArF resist pattern 2 is formed (FIG. 1B).

(2) A step of embedding a high carbon-containing resin composition between the resist patterns 2 and heating the polymer on which the resist pattern 2 is formed and which does not contain silicon atoms in the molecule and contains an aromatic ring After spin-coating a high carbon-containing resin composition for pattern formation as a resin component, pattern 2 is sufficiently covered with a coating 3a obtained by heating on a hot plate at 150 to 200 ° C. for 60 to 120 seconds (FIG. 1). (C)).
After this step, the upper surface of the coating 3a is removed to expose the upper surface of the resist pattern 2 (FIG. 1 (d)).
In the process from FIG. 1C to FIG. 1D, for example, the upper surface of the resist pattern 2 can be exposed by various methods shown in FIG. FIG. 2 is a diagram showing an example of a resist pattern upper surface exposure process.

(2-1) Method of Removing Top Surface of Coating 3a by Dry Method After the step shown in FIG. 1 (c), until the top surface of resist pattern 2 is exposed by plasma etching using oxygen (O ₂ ) gas or the like. The upper surface of the coating 3a is removed by etching (FIGS. 1 and 2 (d)).

(2-2) Method of removing the upper surface of the coating 3a with an alkaline aqueous solution After the step shown in FIG. 1 (c), the coating 3a is coated with a 2.38 mass% tetramethylammonium hydroxide aqueous solution. The coating 3a is removed until the upper surface is exposed (FIG. 2 (c-2)). At this time, the pattern 2 is not removed.

(2-3) Method of removing the upper surface of the film 3a with an organic solvent After the step shown in FIG. 1C, an organic solvent that selectively dissolves only the film 3a is used until the upper surface of the pattern 1 is exposed. Is removed (FIG. 2 (c-2)).

(3) A step of forming a resist pattern 3 (hereinafter referred to as a high carbon-containing pattern 3) made of a polymer having a carbon content higher than that of the resist pattern 2 and containing no silicon atom in the molecule on the substrate 1 to be processed. After the pattern upper surface exposure step, only the resist pattern 2 is removed to form a pattern of a high carbon-containing pattern 3 on the substrate 1 to be processed (FIG. 1E). Examples of the method for removing the resist pattern 2 include the following method shown in FIG. FIG. 3 is a diagram showing an example of a process for removing the resist pattern 2.
(3-1) Method 1 for removing resist pattern 2
Using an ultraviolet irradiation apparatus, a radiation irradiation process (hereinafter also referred to as exposure) is performed on the entire surface of the substrate having the resist pattern 2 and the patterned high carbon-containing pattern 3 (FIG. 3 (d-1)). Thereafter, post-baking is performed on a hot plate at 100 to 130 ° C. for 60 to 120 seconds. By post-baking, the acid-dissociable group of the resist pattern 2 is dissociated by the action of an acid to form a readily alkali-soluble pattern 2b (FIG. 3 (d-2)). Thereafter, using an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38% by mass, development is performed at 25 ° C. for 30 to 120 seconds, washing and drying, and only the high carbon-containing pattern 3 is formed on the substrate 1 to be processed (FIG. 2). And FIG. 3 (e)).
(3-2) Method 2 for removing resist pattern 2
A substrate comprising the resist pattern 2 and the patterned high carbon content pattern 3 on the surface is heated on a hot plate at 150 to 250 ° C. for 30 to 300 seconds to advance the crosslinking curing reaction in the high carbon content pattern 3. Thus, a high carbon content pattern 3 that does not dissolve in the developer or the organic solvent is obtained. Only the high carbon content pattern 3 in FIG. 3D is developed and dried for 30 to 300 seconds using an organic solvent capable of dissolving the resist pattern 2 such as propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, and γ-butyrolactone. Are formed on the substrate 1 (FIGS. 2 and 3E).

The dual damascene structure forming method of the present invention will be described with reference to FIGS. 4 and 5 are process diagrams respectively showing an example of a pattern formation method having a dual damascene structure.
(1) Step of forming a resist pattern on a substrate to be processed After a general planarization layer 5 is formed on a substrate 4 that has already been processed and formed, an ArF made of a polyacrylate or polymethacrylate structure is used. A resin composition solution for pattern formation is spin-coated and prebaked on a hot plate at 100 to 130 ° C. for 30 to 90 seconds to form a resist film 2a having a thickness of 200 nm (FIGS. 4A and 5A). )). Note that the via hole 4a is already formed in the substrate 4 of FIG. 4, and the trench pattern 4b is already formed in the substrate 4 of FIG. The planarizing layer 5 may be a combination of a via hole filling agent made of, for example, a novolac-based composition and a normal lower antireflection film, or may be used alone. The film thickness of the flattening layer 5 is a film thickness at which the reflectance from the substrate 4 is minimized and varies depending on the product, but is generally 30 to 60 nm from the substrate surface.
The substrate on which the resist film 2a is formed is exposed for an optimal exposure time through a mask pattern using an ArF excimer laser exposure apparatus manufactured by NIKON. Then, after post-baking on a hot plate at 100 to 130 ° C. for 60 to 120 seconds, using a 2.38 mass% aqueous tetramethylammonium hydroxide solution, developing at 25 ° C. for 30 to 120 seconds, washing with water, and drying Then, a positive ArF resist pattern 2 is formed (FIGS. 4B and 5B). Reference numeral 6 denotes a base.

(2) Step of embedding a polymer that does not contain silicon atoms in the molecule between the resist patterns 2 A polymer that contains the above resist pattern 2 and does not contain silicon atoms in the molecule and contains an aromatic ring The pattern 2 is sufficiently covered with a film 3a obtained by spin-coating a high carbon-containing resin composition for pattern formation having a resin component as a resin component and heating on a hot plate at 150 to 200 ° C. for 60 to 120 seconds (FIG. 4 (c), FIG. 5 (c)).
After this step, the upper surface of the film 3a is removed to expose the upper surface of the resist pattern 2 (FIGS. 4D and 5D).
In the steps from (c) to (d) of FIGS. 4 and 5, for example, the upper surface of the resist pattern 2 can be exposed by various methods shown in FIG.

(3) Step of forming pattern of high carbon content pattern 3 on planarization layer 5 After the resist pattern upper surface exposure step, only resist pattern 2 is removed and pattern of high carbon content pattern 3 is formed on planarization layer 5 These are formed (FIGS. 4E and 5E). As a method for removing the resist pattern 2 by etching, for example, the method shown in FIG.

(4) Step of forming trench structure or via structure on substrate 4 Using the pattern of the high carbon-containing pattern 3 as a mask, the trench structure 4b or the via structure 4a is formed on the substrate 4. The formation of the trench structure or the via structure is performed by using dry etching, and a condition is adopted in which the etching selectivity is high enough for the high carbon-containing pattern 3 to perform the mask function with respect to the substrate 4 (FIG. 4F). 5 (f)).

(5) Step of peeling off the composition remaining on the substrate 4 after etching The remaining composition is peeled off from the substrate 4 after the formation of the trench structure 4b or via structure 4a under the condition that the substrate 4 hardly changes its shape and physical properties. To do. As general stripping conditions, oxygen ashing, dry stripping using a reduction-type gas plasma such as ammonia gas, wet stripping using a sulfuric acid-hydrogen peroxide solution, or the like can be used (FIG. 4 (g ), FIG. 5 (g)).

The polymer embedded between the resist patterns 2 used in the pattern formation method is a polymer that has better etching resistance than the polymer that forms the resist pattern 2 and does not contain silicon atoms in the molecule. Suitable polymers include polymers having repeating units consisting of hydroxymethyl acenaphthylene and / or hydroxymethyl styrene.
Hydroxymethylacenaphthylene is represented by the above formula (1) (hereinafter also referred to as “repeating unit (1)”), and hydroxymethylstyrene is represented by the above formula (2) (hereinafter referred to as “repeating unit (2)”. ”).

The polymer containing the repeating unit (1) and / or the repeating unit (2) reacts with the acid (H ⁺ ) remaining in the resist pattern 2 by reacting the —CR ₂ OH group contained in the side chain with a cation (— CR ₂ ⁺ ) is formed and this cation reacts with the —CR ₂ OH group to crosslink. In this cross-linking reaction, acid (H ⁺ ) is generated again. Therefore, the above reaction is repeated, and an acid is generated simultaneously with the cross-linking of the —CR ₂ OH group. Since this reaction is a reaction between functional groups on the side chains of the polymer, no low molecular weight substance remains. Furthermore, since the polymer contains many aromatic rings having a carbon-carbon double bond having a higher binding energy than the carbon-carbon single bond, the etching resistance is superior to that of the resist pattern 2.

In the repeating unit (1) and / or the repeating unit (2), the alkyl group having 1 to 3 carbon atoms represented by R ¹ , R ² and R ³ includes a methyl group, an ethyl group, an n-propyl group, i -Propyl group is mentioned.
Examples of the aryl group represented by R ¹ and R ² include a phenyl group, a tolyl group, a naphthyl group, and a biphenyl group.
In the present invention, it is particularly preferable that R ¹ and R ² are hydrogen atoms and n and m are 0.

式（１−１）および（２−１）において、Ｒ¹、Ｒ²およびＲ³は、上記式（１）および式（２）におけるそれと同一である。
繰り返し単位（１）および／または繰り返し単位（２）は、重合体全体に対して、通常１０〜７０モル％、好ましくは３０〜５０モル％含まれる。繰り返し単位（１）および／または繰り返し単位（２）を上記範囲にすることにより、エッチング耐性が向上する。繰り返し単位（１）および／または繰り返し単位（２）が３０モル％より少ないと架橋性能が損なわれることがあり、７０モル％より多いと溶剤に対する溶解性が損なわれることがある。The repeating unit (1) and the repeating unit (2) are obtained by polymerizing monomers represented by the following formulas (1-1) and (2-1).

In the formulas (1-1) and (2-1), R ¹ , R ² and R ³ are the same as those in the above formulas (1) and (2).
The repeating unit (1) and / or the repeating unit (2) is usually contained in an amount of 10 to 70 mol%, preferably 30 to 50 mol%, based on the whole polymer. Etching resistance improves by making a repeating unit (1) and / or a repeating unit (2) into the said range. When the repeating unit (1) and / or the repeating unit (2) is less than 30 mol%, the crosslinking performance may be impaired, and when it is more than 70 mol%, the solubility in a solvent may be impaired.

The polymer embedded between the resist patterns 2 used in the pattern forming method may contain another repeating unit (3) in addition to the repeating unit (1) and / or the repeating unit (2). Examples of the other repeating unit (3) include hydroxystyrene, 2-hydroxyethyl methacrylate, glycidyl methacrylate, N-methylacrylamide, p-hydroxymethacrylanilide and the like.
Other repeating units (3) may be present alone or in combination of two or more. Moreover, it is preferable that it is 30-90 mol% with respect to the whole polymer, and, as for the content rate of another repeating unit (3), it is still more preferable that it is 50-70 mol%.

  The polymer containing the repeating unit (1) and / or the repeating unit (2) has a polystyrene-reduced mass average molecular weight (hereinafter abbreviated as “Mw”) measured by a gel permeation chromatography method, preferably 500 to 500,000. Is 500 to 100,000, more preferably 800 to 50,000, and still more preferably 800 to 10,000. If Mw is less than 500, components may volatilize during film firing and a desired film thickness may not be obtained. If it exceeds 500,000, solubility in a solvent may be reduced.

  For example, the polymer is obtained by polymerizing a polymerizable unsaturated monomer corresponding to each repeating unit constituting a desired molecular composition in a predetermined solvent in the presence of a radical polymerization initiator, a chain transfer agent, or the like. Can be manufactured. The radical polymerization initiator is preferably added so as to have a sufficiently high concentration in order to realize a sufficient polymerization rate.

Although it does not specifically limit as said radical polymerization initiator, A thermal polymerization initiator, a redox polymerization initiator, and a photoinitiator are mentioned. Specific examples include polymerization initiators such as peroxides and azo compounds. More specific radical polymerization initiators include t-butyl hydroperoxide, t-butyl perbenzoate, benzoyl peroxide, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azo. Examples thereof include bisisobutyronitrile (AIBN), 1,1′-azobis (cyclohexanecarbonitrile), dimethyl-2,2′-azobisisobutyrate (MAIB), and the like.
Examples of the chain transfer agent include pyrazole derivatives and alkylthiols.

  As for the polymerization operation, polymerization can be carried out by a usual method such as batch polymerization or dropping polymerization. For example, the monomer (1-1), the monomer (2-1), and a monomer corresponding to the other repeating unit (3) are prepared, and the necessary types and amounts are prepared in an organic solvent. The polymer of the vinyl naphthalene derivative of this embodiment is obtained by dissolving and polymerizing in the presence of a radical polymerization initiator and a chain transfer agent. As the polymerization solvent, an organic solvent capable of dissolving the monomer, radical polymerization initiator and chain transfer agent is generally used. Examples of the organic solvent include alcohol solvents, ketone solvents, ether solvents, aprotic polar solvents, ester solvents, aromatic solvents, and linear or cyclic aliphatic solvents. Examples of the alcohol solvent include 2-propanol, butanol, propylene glycol monomethyl ether and the like. Examples of the ketone solvent include methyl ethyl ketone and acetone. Examples of ether solvents include alkoxyalkyl ethers such as methoxymethyl ether, ethyl ether, tetrahydrofuran, and 1,4-dioxane. Examples of the aprotic polar solvent include dimethylformamide and dimethylsulfoxide. Examples of ester solvents include alkyl acetates such as ethyl acetate and methyl acetate. Aromatic solvents include alkylaryl solvents such as toluene, xylene, and halogenated aromatic solvents such as chlorobenzene. Examples of the aliphatic solvent include hexane and cyclohexane.

  The polymerization temperature is generally 20 to 120 ° C, preferably 50 to 110 ° C, more preferably 60 to 100 ° C. Although polymerization may be performed even in a normal air atmosphere, polymerization in an inert gas atmosphere such as nitrogen or argon is preferable. The molecular weight of the vinyl naphthalene derivative polymer of this embodiment can be adjusted by controlling the ratio of the monomer amount and the chain transfer agent amount. The polymerization time is generally 0.5 to 144 hours, preferably 1 to 72 hours, more preferably 2 to 24 hours.

The said polymer can be used as a resin component of the high carbon content resin composition used for the pattern formation method of this invention.
Examples of the solvent contained in the high carbon-containing resin composition include methanol, ethanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, and 1-hexanol. 2-hexanol, 3-hexanol, 2-methyl-1-butanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 4-methyl-2- Alcohols such as pentanol, ethers such as diethyl ether, diisopropyl ether, dipropyl ether, and dibutyl ether can be appropriately selected and used. There is no particular limitation as long as it does not dissolve the organic resist film for ArF having a polyacrylate or polymethacrylate structure.

  Of these solvents, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol and the like are preferable. The said solvent can be used individually or in mixture of 2 or more types. The amount of the solvent used is a range in which the solid content concentration of the obtained composition is preferably 0.01 to 70% by mass, more preferably 0.05 to 60% by mass, and particularly preferably 0.1 to 50% by mass. It is.

Various additives such as an acid generator, a crosslinking agent, a binder resin, a radiation absorber, and a surfactant can be blended with the high carbon-containing resin composition as necessary.
The acid generator is a component that generates an acid upon exposure or heating. Examples of the acid generator that generates an acid upon exposure (hereinafter referred to as “photoacid generator”) include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, and diphenyliodonium n. -Dodecylbenzene sulfonate, diphenyl iodonium 10-camphor sulfonate, diphenyl iodonium naphthalene sulfonate, diphenyl iodonium hexafluoroantimonate,
Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium n-dodecylbenzenesulfonate, bis ( 4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylphenyl) iodonium naphthalenesulfonate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate,

Triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium n-dodecylbenzenesulfonate, triphenylsulfonium naphthalenesulfonate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium hexafluoroantimonate,
4-hydroxyphenyl phenyl methylsulfonium p-toluenesulfonate, 4-hydroxyphenyl benzyl methylsulfonium p-toluenesulfonate, cyclohexyl methyl 2-oxocyclohexylsulfonium trifluoromethanesulfonate, 2-oxocyclohexyldicyclohexylsulfonium trifluoromethanesulfonate 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate,

1-naphthyldimethylsulfonium trifluoromethanesulfonate, 1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-cyano-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-nitro-1- Naphthyldimethylsulfonium trifluoromethanesulfonate, 4-nitro-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4-methyl-1-naphthyldiethylsulfonium trifluoromethanesulfonate, 4-hydroxy- 1-naphthyldimethylsulfonium trifluoromethanesulfonate, 4 Hydroxy-1-naphthyl diethyl sulfonium trifluoromethane sulfonate,
1- (4-hydroxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxymethoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethane Sulfonate,

1- [4- (1-methoxyethoxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- [4- (2-methoxyethoxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-methoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-ethoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n -Propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate,
1- (4-i-propoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1 -(4-t-butoxycarbonyloxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- [4- (2-tetrahydrofuranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate, 1 -[4- (2-tetrahydropyranyloxy) naphthalen-1-yl] tetrahydrothiophenium trifluoromethanesulfonate,
Onium salt photoacid generators such as 1- (4-benzyloxy) tetrahydrothiophenium trifluoromethanesulfonate, 1- (naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate;

Halogen-containing compound-based photoacid generators such as phenylbis (trichloromethyl) -s-triazine, 4-methoxyphenylbis (trichloromethyl) -s-triazine, 1-naphthylbis (trichloromethyl) -s-triazine;
1,2-naphthoquinonediazide-4-sulfonyl chloride, 1,2-naphthoquinonediazide-5-sulfonyl chloride, 1,2, naphthoquinonediazide-4-sulfonic acid ester of 2,3,4,4′-tetrahydroxybenzophenone or Diazoketone compound-based photoacid generators such as 1,2-naphthoquinonediazide-5-sulfonic acid ester;
Sulfone compound photoacid generators such as 4-trisphenacylsulfone, mesitylphenacylsulfone, bis (phenylsulfonyl) methane;
Benzoin tosylate, pyrogallol tris (trifluoromethanesulfonate), nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate, trifluoromethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-di Examples thereof include sulfonic acid compound photoacid generators such as carbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate.

  Among these photoacid generators, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium pyrenesulfonate, diphenyliodonium n-dodecylbenzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium naphthalenesulfonate, Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium n-dodecylbenzenesulfonate, bis ( 4-t-butylphenyl) iodonium 10-camphorsulfonate, bis (4-t-butylphenyl) Etc. iodonium naphthalene sulfonate is preferred. The photoacid generators can be used alone or in admixture of two or more.

  Examples of the acid generator that generates an acid by heating (hereinafter referred to as “thermal acid generator”) include 2,4,4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl, and the like. Tosylate, alkyl sulfonates and the like can be mentioned. These thermal acid generators can be used alone or in admixture of two or more. Moreover, a photo-acid generator and a thermal acid generator can also be used together as an acid generator.

  50 mass% or less is preferable as a ratio in solid content of the composition obtained, as for the compounding quantity of an acid generator, 0.1-30 mass% is further more preferable, and 0.1-10 mass% is especially preferable.

  Moreover, the said crosslinking agent is a component which accelerates | stimulates hardening reaction of the planarization film which consists of a polymer which has a repeating unit (1) and / or a repeating unit (2). As such a crosslinking agent, polynuclear phenols and various commercially available curing agents can be used. Examples of the polynuclear phenols include binuclear phenols such as 4,4′-biphenyldiol, 4,4′-methylene bisphenol, 4,4′-ethylidene bisphenol, and bisphenol A; 4,4 ′, 4 ″. -Trinuclear phenols such as methylidenetrisphenol, 4,4 '-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol; polyphenols such as novolak Can be mentioned. Of these polynuclear phenols, 4,4 ′-[1- {4- (1- [4-hydroxyphenyl] -1-methylethyl) phenyl} ethylidene] bisphenol, novolac and the like are preferable. The above polynuclear phenols can be used alone or in admixture of two or more.

  Examples of the curing agent include 2,3-tolylene diisocyanate, 2,4-tolylene diisocyanate, 3,4-tolylene diisocyanate, 3,5-tolylene diisocyanate, and 4,4 ′. -Diisocyanates such as diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, and the following trade names: Epicoat 812, 815, 826, 828, 834, 834 871, 1001, 1004, 1007, 1007, 1009, 1031 (Oilized Shell Epoxy), Araldite 6600, 6700, 6800, 502, 6071, 6084, 6097, 6099 (above, manufactured by Ciba Geigy), DER331, 332, 333, 66 1, epoxy compound such as 644, 667 (manufactured by Dow Chemical Co.); Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712, Melting agents such as 701, 272, 202, My Coat 506, 508 (above, manufactured by Mitsui Cyanamid Co., Ltd.); Cymel 1123, 1123-10, 1128, My Coat 102, 105, Benzoguanamine type curing agents such as 106, 130 (above, Mitsui Cyanamid Co., Ltd.), etc .; Cymel 1170, 1172 (above, Mitsui Cyanamid Co., Ltd.), Nicarak N-2702 (Sanwa Chemical Co., Ltd.) ) And the like. Of these curing agents, melamine curing agents, glycoluril curing agents and the like are preferable. The said hardening | curing agent can be used individually or in mixture of 2 or more types. Moreover, polynuclear phenols and a hardening | curing agent can also be used together as a crosslinking agent.

  As for the compounding quantity of a crosslinking agent, the ratio in solid content of the composition obtained is preferable 50 mass% or less, and 30 mass% or less is still more preferable.

As the binder resin, various thermoplastic resins and thermosetting resins can be used. Examples of the thermoplastic resin include polyethylene, polypropylene, poly-1-butene, poly-1-pentene, poly-1-hexene, poly-1-heptene, poly-1-octene, poly-1-decene, and poly-1-decene. Α-Olefin-based polymers such as -1-dodecene, poly-1-tetradecene, poly-1-hexadecene, poly-1-octadecene, and polyvinylcycloalkane; poly-1,4-pentadiene, poly-1,4- Non-conjugated diene polymers such as hexadiene and poly-1,5-hexadiene;
α, β-unsaturated aldehyde polymers; α, β-unsaturated ketone polymers such as poly (methyl vinyl ketone), poly (aromatic vinyl ketone), poly (cyclic vinyl ketone); (meth) acrylic acid Polymers of α, β-unsaturated carboxylic acids or derivatives thereof such as, α-chloroacrylic acid, (meth) acrylate, (meth) acrylic acid ester, (meth) acrylic acid halide; Polymers of α, β-unsaturated carboxylic acid anhydrides such as copolymers of acrylic acid anhydride and maleic anhydride; Polymers of unsaturated polybasic carboxylic acid esters such as methylenemalonic acid diester and itaconic acid diester Kind;

Polymers of diolefin carboxylic acid esters such as sorbic acid ester and muconic acid ester; Polymers of α, β-unsaturated carboxylic acid thioesters such as (meth) acrylic acid thioester and α-chloroacrylic acid thioester; ) Polymers of (meth) acrylonitrile such as acrylonitrile and α-chloroacrylonitrile or derivatives thereof; Polymers of (meth) acrylamide or derivatives thereof such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide; Polymers of metal compounds; Polymers of vinyloxy metal compounds;
Polyimines; polyethers such as polyphenylene oxide, poly-1,3-dioxolane, polyoxirane, polytetrahydrofuran, polytetrahydropyran; polysulfides; polysulfonamides; polypeptides; nylon 66, nylon 1 to nylon 12, etc. Polyamides; Polyesters such as aliphatic polyesters, aromatic polyesters, alicyclic polyesters and polycarbonates; Polyureas; Polysulfones; Polyazines; Polyamines; Polyaromatic ketones; Polyimides; Polybenzoxazoles; polybenzothiazoles; polyaminotriazoles; polyoxadiazoles; polypyrazoles; polytetrazoles; polyquinoxalines; polytriazines; Down like; quinoline compounds; mention may be made of a poly-Anne tiger gelsolin, and the like.

  Moreover, the said thermosetting resin is a component which hardens | cures by heating, becomes insoluble in a solvent, and has an effect | action which prevents the intermixing between the resist patterns 2, and can be preferably used as binder resin. Examples of such thermosetting resins include thermosetting acrylic resins, phenol resins, urea resins, melamine resins, amino resins, aromatic hydrocarbon resins, epoxy resins, alkyd resins. Etc. Of these thermosetting resins, urea resins, melamine resins, aromatic hydrocarbon resins and the like are preferable.

  The above binder resins can be used alone or in admixture of two or more. 20 mass% or less is preferable in the solid content of the composition obtained, and, as for the compounding quantity of binder resin, 10 mass% or less is still more preferable.

  Examples of the radiation absorber include oil-soluble dyes, disperse dyes, basic dyes, methine dyes, pyrazole dyes, imidazole dyes, hydroxyazo dyes, and the like; bixin derivatives, norbixine, stilbene, Fluorescent brighteners such as 4,4′-diaminostilbene derivatives, coumarin derivatives, pyrazoline derivatives; hydroxyazo dyes, tinuvin 234 (trade name, manufactured by Ciba Geigy), tinuvin 1130 (trade name, manufactured by Ciba Geigy), etc. Ultraviolet absorbers; aromatic compounds such as anthracene derivatives and anthraquinone derivatives. These radiation absorbers can be used alone or in admixture of two or more. 100 mass% or less is preferable in the solid content of the composition obtained, and, as for the compounding quantity of a radiation absorber, 50 mass% or less is still more preferable.

  The surfactant is a component having an effect of improving coatability, striation, wettability, developability and the like. Examples of such surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene-n-octylphenyl ether, polyoxyethylene-n-nonylphenyl ether, and polyethylene. Nonionic surfactants such as glycol dilaurate and polyethylene glycol distearate, and KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, manufactured by Kyoeisha Yushi Chemical Co., Ltd.), Ftop EF101, EF204, EF303, EF352 (above, manufactured by Tochem Products), MegaFuck F171, F172, F173 (above, Dainippon) Ink Chemical Industry Co., Ltd.), Florard FC430, FC431, FC135, FC135, FC93 (above, manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S382, SC101, SC102, SC103, SC104, SC105, SC106 (above, manufactured by Asahi Glass Co., Ltd.) and the like. These surfactants can be used alone or in admixture of two or more. The blending amount of the surfactant is preferably 15% by mass or less, and more preferably 10% by mass or less in the solid content of the obtained composition. Furthermore, examples of additives other than those described above include storage stabilizers, antifoaming agents, and adhesion aids.

A composition comprising a polymer having a repeating unit (1) and / or a repeating unit (2) in a high carbon-containing resin composition embedded between resist patterns 2 and formed by removing the resist pattern 2 The solid content concentration is preferably 0.05 to 60% by mass, more preferably 0.1 to 50% by mass.
If the solid content concentration is less than 0.05% by mass, the coating film may be too thin to sufficiently cover the resist pattern, and if it exceeds 60% by mass, the viscosity may be too high, resulting in poor applicability. There is a possibility that it cannot be embedded in a fine pattern.
Moreover, it is preferable that the ratio of the polymer which has a repeating unit (1) and / or a repeating unit (2) which occupies in a composition is 60 mass% or more with respect to the whole resin component.
The high carbon-containing resin composition containing the polymer having the repeating unit (1) and / or the repeating unit (2) as a resin component is capable of emitting various radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, and X-ray. It can be used very suitably for microfabrication in the lithography process to be used, for example, in the manufacture of integrated circuit elements.

The case where the said high carbon containing resin composition is used for the pattern formation method (FIGS. 1-5) of this invention is demonstrated.
Examples of the substrate to which the resin composition is to be applied include a substrate in which an ArF organic resist pattern 2 having a polyacrylic acid ester structure or a polymethacrylic acid ester structure is formed on a silicon wafer 1.
Application | coating of the resin composition for pattern formation containing the polymer which has a repeating unit (1) and / or a repeating unit (2) can be implemented by appropriate methods, such as spin coating, cast coating, and roll coating. Thereafter, the coating film is cured by heating. When the resin composition for pattern formation contains a photoacid generator and is subjected to radiation irradiation treatment (exposure), the coating film can be effectively cured even at room temperature. The heating temperature is preferably 50 to 300 ° C, more preferably 150 to 250 ° C. When the high carbon-containing resin composition contains a thermal acid generator, for example, the coating film is effective even at about 90 to 130 ° C. Can be cured.

The film thickness of the high carbon-containing resin composition is as follows: an ArF organic resist pattern 2 having a polyacrylate or polymethacrylate structure formed on the silicon wafer 1.
Should be sufficiently covered, and generally the thickness is preferably 30 to 500 nm. By setting this range, the resist pattern 2 formed on the silicon wafer 1 can be effectively covered and flattened. If the thickness is less than 30 nm, the above effect may be difficult to obtain. If the thickness is more than 500 nm, the etching for exposing the upper surface of the resist pattern 2 formed on the silicon wafer 1 may take too much time.

The high carbon-containing resin composition is excellent in etching resistance and does not cause intermixing with the organic resist pattern coating for ArF having a polyacrylate or polymethacrylate structure, so that the shape of the resist pattern 2 is deformed. The film can be flattened without any problem, and a subsequent transfer process can provide a single layer resist pattern with excellent etching resistance. Therefore, the high carbon-containing resin composition comprising a polymer having the repeating unit (1) and / or the repeating unit (2) is a lithography using various kinds of radiation such as visible light, ultraviolet light, far ultraviolet light, electron beam, and X-ray. It can be used very suitably for microfabrication by a process, for example, the manufacture of an integrated circuit element.
Moreover, since this invention does not ask | require the kind of to-be-processed substrate, it can utilize suitably also for dual damascene structure formation, for example.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not restrict | limited at all by these Examples. Here, the part is based on mass unless otherwise specified. Each measurement and evaluation in Examples and Comparative Examples was performed as follows.

Example 1
A polymer (I) having a repeating unit composed of hydroxymethylacenaphthylene was prepared, and a high carbon-containing resin composition (I) was prepared using the polymer (I).

温度計を備えたセパラブルフラスコに、窒素雰囲気下で、４−アセトキシスチレン（Ｐ−１−２）９質量部、５−ヒドロキシメチルアセナフチレン（Ｐ−１−１）６質量部、プロピレングリコールモノメチルエーテル１８０質量部およびジメチル−２，２'−アゾビスイソブチレート５質量部を含む混合溶液を加え、攪拌しつつ６０℃で６時間重合した。
その後、反応溶液を９５℃に昇温した後１時間加熱した。反応溶液を２分の１質量に減圧濃縮した後、大量のヘプタン中に投入して反応生成物を再沈させた。温度計を備えたセパラブルフラスコに、窒素雰囲気下で、得られた固形分全量、テトラヒドロフラン１００質量部、メタノール１００質量部、トリエチルアミン７質量部および水３質量部を加え、攪拌しつつ７時間加熱還流した。反応溶液を２分の１質量に減圧濃縮した後、大量のヘプタン中に投入して固形分を１８ｇ得た。この重合体のＭｗは１，８００であった。なお、Ｍｗは、東ソー（株）社製ＧＰＣカラム（Ｇ２０００ＨＸＬ２本、Ｇ３０００ＨＸＬ１本、Ｇ４０００ＨＸＬ１本）を用い、流量１．０ミリリットル／分、溶出溶剤テトラヒドロフラン、カラム温度４０℃の分析条件で、単分散ポリスチレンを標準とするゲルパーミエーションクロマトグラフィー（ＧＰＣ）により測定した。Polymer (I) having a repeating unit composed of hydroxymethylacenaphthylene

In a separable flask equipped with a thermometer, 9 parts by mass of 4-acetoxystyrene (P-1-2), 6 parts by mass of 5-hydroxymethylacenaphthylene (P-1-1), propylene glycol under a nitrogen atmosphere A mixed solution containing 180 parts by mass of monomethyl ether and 5 parts by mass of dimethyl-2,2′-azobisisobutyrate was added, and polymerization was performed at 60 ° C. for 6 hours while stirring.
Thereafter, the reaction solution was heated to 95 ° C. and then heated for 1 hour. The reaction solution was concentrated under reduced pressure to a half mass, and then poured into a large amount of heptane to reprecipitate the reaction product. To a separable flask equipped with a thermometer, the total amount of the solid content obtained, 100 parts by mass of tetrahydrofuran, 100 parts by mass of methanol, 7 parts by mass of triethylamine and 3 parts by mass of water were added and heated for 7 hours while stirring. Refluxed. The reaction solution was concentrated under reduced pressure to a half mass, and then poured into a large amount of heptane to obtain 18 g of a solid content. The Mw of this polymer was 1,800. Mw is a monodisperse polystyrene using a GPC column (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, under the analysis conditions of a flow rate of 1.0 ml / min, an elution solvent tetrahydrofuran, and a column temperature of 40 ° C. Was measured by gel permeation chromatography (GPC).

High carbon-containing resin composition (I)
10 parts by mass of the obtained polymer (I) and 0.1 part by mass of bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate were dissolved in 190 parts by mass of 4-methyl-2-pentanol. A high carbon-containing resin composition (I) was obtained.

Formation of organic resist pattern 2 An antireflection film-forming composition is spin-coated on a silicon wafer having a diameter of 8 inches, and then heated on a hot plate at 200 ° C. for 120 seconds to form an antireflection film having a thickness of 36 nm on the silicon wafer. Formed. Thereafter, on this antireflection film, an ArF organic resist composition solution having a polymethacrylate structure (product name: AR1221J, manufactured by JSR Corporation) was spin-coated, and prebaked on a hot plate at 100 ° C. for 60 seconds. A resist film having a thickness of 200 nm was formed. Thereafter, exposure was performed for a specified exposure time through a mask pattern using an ArF excimer laser exposure apparatus manufactured by NIKON. Then, after post-baking on a hot plate at 110 ° C. for 60 seconds, using a 2.38 mass% concentration of tetramethylammonium hydroxide aqueous solution, developing at 25 ° C. for 30 seconds, washing with water and drying, a positive organic A line and space pattern 2 having a line width of 90 nm of an ArF resist was formed.

Film formation and etching of high carbon-containing resin composition (I) Obtained by spin-coating high carbon-containing resin composition (I) on organic ArF resist pattern 2 and then heating on a hot plate at 150 ° C. for 120 seconds. The pattern 2 was sufficiently covered and flattened with the high carbon-containing pattern 3 coating. Thereafter, the film of the high carbon-containing pattern 3 was removed by plasma etching using O ₂ gas until the upper surface of the pattern 2 was exposed. The etching time was calculated from the etching rate per unit time measured in advance using a single film having a high carbon-containing pattern 3.

Formation of Pattern (I) Using a KrF excimer laser exposure apparatus manufactured by NIKON, the entire surface of the substrate having the resist pattern 2 and the high carbon-containing pattern 3 is exposed. Then, after post-baking on a hot plate at 130 ° C. for 60 seconds, using a 2.38 mass% concentration of tetramethylammonium hydroxide aqueous solution, developing at 25 ° C. for 60 seconds, washing and drying, 90 nm line and space Only pattern 3 was formed. The pattern of the high carbon-containing pattern 3 is defined as an evaluation pattern (I).

Example 2
The same operation as in Example 1 was performed until the formation of the organic resist pattern 2.
Film formation and etching of high carbon-containing resin composition (I) Obtained by spin-coating high carbon-containing resin composition (I) on organic ArF resist pattern 2 and then heating on a hot plate at 100 ° C. for 120 seconds. The pattern 2 was sufficiently covered and flattened with the coating 3a to be formed. Next, the coating 3a was etched using 4-methyl-2-pentanol which selectively dissolves only the coating 3a until the upper surface of the pattern 2 was exposed. Next, the substrate was heated on a hot plate at 150 ° C. for 120 seconds to crosslink and cure the coating 3 a to obtain a pattern of the polymer 3. Under this condition, pattern 2 was not crosslinked and cured.

Formation of pattern (Ia) Using propylene glycol monomethyl ether acetate capable of dissolving pattern 2, development and drying were carried out for 120 seconds, and only a 90 nm line and space pattern consisting of high carbon-containing pattern 3 could be formed.

温度計を備えたセパラブルフラスコに、窒素雰囲気下で、４−アセトキシスチレン（Ｐ−２−２）９質量部、４−ヒドロキシメチルスチレン（Ｐ−２−１）６質量部、プロピレングリコールモノメチルエーテル１８０質量部およびジメチル−２，２'−アゾビスイソブチレート５質量部を含む混合溶液を加え、攪拌しつつ６０℃で６時間重合した。その後、反応溶液を９５℃に昇温した後１時間加熱した。反応溶液を２分の１質量に減圧濃縮した後、大量のヘプタン中に投入して反応生成物を再沈させた。温度計を備えたセパラブルフラスコに、窒素雰囲気下で、得られた固形分全量、テトラヒドロフラン１００質量部、メタノール１００質量部、トリエチルアミン７質量部および水３質量部を加え、攪拌しつつ７時間加熱還流した。反応溶液を２分の１質量に減圧濃縮した後、大量のヘプタン中に投入して固形分を１８ｇ得た。実施例１と同様にして測定した、この重合体のＭｗは２，０００であった。Example 3
A polymer (II) having a repeating unit composed of hydroxymethylstyrene was prepared, and a high carbon-containing resin composition (II) was prepared using the polymer (II).
Polymer (II) having a repeating unit composed of hydroxymethylstyrene

In a separable flask equipped with a thermometer, 9 parts by mass of 4-acetoxystyrene (P-2-2), 6 parts by mass of 4-hydroxymethylstyrene (P-2-1), propylene glycol monomethyl ether in a nitrogen atmosphere A mixed solution containing 180 parts by mass and 5 parts by mass of dimethyl-2,2′-azobisisobutyrate was added, and polymerization was performed at 60 ° C. for 6 hours while stirring. Thereafter, the reaction solution was heated to 95 ° C. and then heated for 1 hour. The reaction solution was concentrated under reduced pressure to a half mass, and then poured into a large amount of heptane to reprecipitate the reaction product. To a separable flask equipped with a thermometer, the total amount of the solid content obtained, 100 parts by mass of tetrahydrofuran, 100 parts by mass of methanol, 7 parts by mass of triethylamine and 3 parts by mass of water were added and heated for 7 hours while stirring. Refluxed. The reaction solution was concentrated under reduced pressure to a half mass, and then poured into a large amount of heptane to obtain 18 g of a solid content. The Mw of this polymer measured in the same manner as in Example 1 was 2,000.

High carbon content resin composition (II)
10 parts by mass of the obtained polymer and 0.1 part by mass of bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate were dissolved in 190 parts by mass of 4-methyl-2-pentanol to contain high carbon. Resin composition (II) was obtained.

Formation of Organic Resist Pattern After spin coating the antireflection film forming composition on a silicon wafer having a diameter of 8 inches, it was heated on a hot plate at 200 ° C. for 120 seconds to form an antireflection film having a thickness of 36 nm on the silicon wafer. Formed. Thereafter, an ArF organic resist composition solution having a polymethacrylate structure used in Example 1 was spin-coated on this antireflection film, prebaked on a hot plate at 100 ° C. for 60 seconds, and a film thickness of 200 nm. The resist film was formed. Thereafter, exposure was performed for a specified exposure time through a mask pattern using an ArF excimer laser exposure apparatus manufactured by NIKON. Then, after post-baking on a hot plate at 110 ° C. for 60 seconds, using a 2.38 mass% concentration of tetramethylammonium hydroxide aqueous solution, developing at 25 ° C. for 30 seconds, washing with water and drying, a positive organic A 150 nm diameter dot pattern of ArF resist was formed.

Film formation and etching of high carbon-containing resin composition (II) Obtained by spin-coating high carbon-containing resin composition (II) on an organic ArF resist dot pattern and then heating it on a hot plate at 100 ° C. for 120 seconds. The dot pattern was sufficiently covered and flattened with the resulting coating. Next, the coating film was etched using an aqueous tetramethylammonium hydroxide solution having a concentration of 2.38 mass% until the upper surface of the dot pattern was exposed. At this time, the dot pattern was not etched. The substrate was then heated on a hot plate at 150 ° C. for 120 seconds to crosslink and cure the embedded pattern. Under this condition, the dot pattern was not crosslinked and cured.

Formation of Embedded Pattern Using an ArF excimer laser exposure apparatus manufactured by NIKON, the entire surface of the substrate composed of a dot pattern and an embedded pattern is exposed. Then, after post-baking on a hot plate at 130 ° C. for 60 seconds, using a 2.38 mass% concentration of tetramethylammonium hydroxide aqueous solution, developing at 25 ° C. for 60 seconds, washing with water and drying, a hole pattern with a diameter of 150 nm Only an evaluation pattern (II) was formed.

Etching performance evaluation Using the organic ArF resist film used in Example 1 as an evaluation pattern (I), the evaluation pattern (II) obtained in Example 1 and Example 3, and the comparative example, Table 1 Etching resistance was compared under the conditions shown. The obtained results are shown in Table 1.

  From Table 1, it can be seen that the coatings composed of the compositions of Examples 1 and 3 have better etching resistance than the ArF resist composition coating (Comparative Example).

  The pattern forming method of the present invention can form a pattern having sufficient etching resistance under conditions for etching a substrate to be processed in a lithography process, and is a multilayer resist process applied when using a resist pattern having poor etching resistance The substrate to be processed can be etched by a so-called single-layer resist process that does not increase the manufacturing cost and decrease the processing capacity, which are disadvantages of the above. Moreover, since this invention does not ask | require the kind of to-be-processed substrate, it can utilize suitably also for dual damascene structure formation, for example. Moreover, the pattern forming composition comprising a polymer having a repeating unit comprising hydroxymethyl acenaphthylene and / or hydroxymethyl styrene used in the pattern forming method of the present invention is effective for establishing the pattern forming method of the present invention. It has excellent etching resistance and contains a functional group that undergoes a crosslinking reaction at a relatively low temperature. Therefore, it can be suitably used in the pattern forming method of the present invention.

It is process drawing of a pattern formation method. It is process drawing of a pattern formation method. It is process drawing of a pattern formation method. It is process drawing of the pattern formation method of a dual damascene structure. It is process drawing of the pattern formation method of a dual damascene structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon wafer 2 Resist pattern 3 High carbon containing pattern 4 Substrate 5 Planarization layer 6 Base

Claims (8)

Forming a resist pattern on the substrate to be processed;
Embedding and heating a high carbon-containing resin composition containing a polymer and a solvent having a carbon content higher than that of the resist pattern and not containing silicon atoms in the molecule between the resist patterns;
Removing only the resist pattern and forming a pattern of the polymer on the substrate to be processed. In the pattern formation method of Claim 1,
The pattern formation method characterized by the carbon content rate of the said high carbon containing resin composition being 80 mass% or more. In the pattern formation method of Claim 2,
A pattern forming method comprising performing a radiation irradiation treatment after the step of embedding the resin composition. In the pattern formation method of Claim 3,
The pattern forming method is a dual damascene structure forming method . A high carbon-containing resin composition used in the pattern forming method according to claim 1,
The high carbon-containing resin composition contains a polymer having a carbon content higher than that of the resist pattern and containing no silicon atom in the molecule and a solvent,
The polymer which comprises this resin composition contains the repeating unit containing an aromatic ring in a molecule | numerator, The high carbon content resin composition characterized by the above-mentioned . In the high carbon content resin composition according to claim 5,
The repeating unit containing an aromatic ring in the molecule includes at least one repeating unit selected from repeating units represented by the following formula (1) and the following formula (2), and the polymer is gel permeation chromatography. A high carbon-containing resin composition having a polystyrene-reduced mass average molecular weight of 500 to 500,000 measured by a method.

(In the formula (1) and (2), R ¹ and R ² represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an aryl group,, R ³ is an alkyl group having 1 to 3 carbon atoms, (A vinyl group, an allyl group, or an aryl group is represented, n represents 0 or 1, m represents 0, 1 or 2.) The high carbon content resin composition according to claim 6,
Wherein in the repeating unit, high-carbon-containing resin composition, wherein R ¹ and R ² are hydrogen atoms, the n and m is 0. In the high carbon content resin composition according to claim 5,
Solvents, alcohols and high-carbon resin composition characterized in that it comprises at least one solvent selected from ethers constituting the resin composition.

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