JP2012216627A - Curable composition for nanoimprint lithography and patterning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition for nanoimprint lithography capable of forming a shape transfer layer less susceptible to peeling of a resist film in a patterning method by nanoimprint lithography.SOLUTION: The curable composition for nanoimprint lithography contains (A) a polymerizable compound, and (B) an organic solvent having a value of relative evaporation speed, measured in compliance to ASTM-D3539 under condition of 25°C and 1 atm, in a range of 1-15 when a value of butyl acetate is 1. For 100 pts.wt. of (A) component, 0.01-10 pts.wt. of (B) component are contained.

Description

  The present invention relates to a curable composition for nanoimprint lithography and a pattern forming method, and more particularly, to a curable composition for nanoimprint lithography used for nanoimprint lithography used for improving the degree of integration and recording density of circuits such as semiconductor elements. And a pattern forming method using the same.

In order to improve the integration degree and recording density of circuits such as semiconductor elements, a finer processing technique is required. As a fine processing technique, a photolithography technique using an exposure process can perform a fine processing of a large area at a time, but does not have a resolution below the wavelength of light. Accordingly, in recent years, photolithography technology using short-wavelength light of 193 nm (ArF), 157 nm (F ₂ ), and 13.5 nm (EUV) has been developed. However, when the wavelength of light is shortened, the number of substances that can transmit light of that wavelength is limited.

  On the other hand, in methods such as electron beam lithography and focused ion beam lithography, the resolution does not depend on the wavelength of light, and a fine structure can be produced.

  On the other hand, as a technique for producing a fine structure having a wavelength equal to or less than the wavelength of light at high throughput, a stamper on which a predetermined fine concavo-convex pattern has been prepared in advance by electron beam lithography or the like is pressed against a substrate coated with a resist. There is known a nanoimprinting method in which a film is transferred to a resist film on a substrate (see, for example, Patent Documents 1 to 3 and Non-Patent Documents 1 and 2).

US Pat. No. 5,772,905 US Pat. No. 5,956,216 JP 2008-162190 A

S. Wy. S. Y. Chou, “Nano Imprint Lithography technology” Applied Physics Letters, Vol. 76, 1995, p. 3114

  In the nanoimprint method described above, there are various problems to be solved in realizing this. One of them is the problem of “resist film peeling”. In the nanoimprint method, the resist-coated substrate is heated above the glass transition temperature to soften the resist, so that when the pressed stamper is peeled off from the resist film, the resist film is peeled off with a part of the resist film attached. This is sometimes referred to as “resist film peeling”.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to form a shape transfer layer in which the resist film hardly peels off in the pattern forming method. It is providing the curable composition for nanoimprint lithography. Moreover, the place made into the subject is providing the pattern formation method with which peeling of a resist film does not arise easily.

  According to the present invention, the following curable composition for nanoimprint lithography and a pattern forming method are provided.

[1] (A) A polymerizable compound (hereinafter also referred to as “compound (A)”) and (B) a value of a relative evaporation rate measured in accordance with ASTM-D3539 under conditions of 25 ° C. and 1 atm. And an organic solvent (hereinafter also referred to as “organic solvent (B)”) in the range of 1 to 15 when the value of butyl acetate is 1, and (B) with respect to 100 parts by weight of component (B) ) A curable composition for nanoimprint lithography containing 0.01 to 10 parts by weight of the component.
[2] The curable composition for nanoimprint lithography according to [1], wherein the content of the component (B) is 0.1 to 1 part by weight with respect to 100 parts by weight of the component (A).
[3] The curable composition for nanoimprint lithography according to any one of [1] or [2], wherein the component (B) is at least one solvent selected from alcohol-based or ketone-based solvents.
[4] The curable composition for nanoimprint lithography according to any one of [1] to [3], further comprising (C) a photopolymerization initiator (hereinafter also referred to as “initiator (C)”).
[5] A step (1) of forming a shaped transfer layer comprising the curable composition for nanoimprint lithography according to any one of claims 1 to 4,
A step (2) of pressing a stamper on the shape transfer layer;
Exposing the shape-transfer layer while the stamper is in pressure contact with (3);
A step (4) of separating the stamper from the shape transfer layer;
A pattern forming method including:

  The curable composition for nanoimprint lithography of the present invention has an effect that a shape transfer layer in which peeling of a resist film hardly occurs can be formed in a pattern forming method by nanoimprint lithography.

  Further, according to the pattern forming method of the present invention, there is an effect that the resist film hardly peels off.

It is a schematic diagram which shows an example of the state after forming a to-be-shaped transfer layer on a board | substrate. It is a schematic diagram showing an example of a state in which a stamper is pressed against a shape transfer layer. It is a schematic diagram showing an example of a state in which the shape-transferred layer is exposed with the stamper pressed. It is a schematic diagram which shows an example of the state after peeling a stamper from a shape transfer layer. It is a schematic diagram which shows an example of the state after etching.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and based on ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that modifications, improvements, and the like appropriately added to the embodiments described above fall within the scope of the present invention.

I. Curable composition for nanoimprint lithography The curable composition for nanoimprint lithography of the present invention (hereinafter also simply referred to as “curable composition”) contains the compound (A) and the organic solvent (B), ) Component (B) contains 0.01 to 10 parts by weight per 100 parts by weight of component.

1. Compound (A)
The compound (A) is a compound having a polymerizable functional group, and specific examples thereof include a radical polymerizable compound and a cationic polymerizable compound. Two or more kinds of polymerizable compounds may be used, and a radical polymerizable compound and a cationic polymerizable compound may be used in combination.

Examples of the radical polymerizable compound include compounds having one or more ethylenically unsaturated bond groups.
Examples of the compound having one ethylenically unsaturated bond group include acrylamide, (meth) acryloylmorpholine, 7-amino-3,7-dimethyloctyl (meth) acrylate, isobutoxymethyl (meth) acrylamide, and isobornyl. Oxyethyl (meth) acrylate, isobornyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethyl diethylene glycol (meth) acrylate, t-octyl (meth) acrylamide, diacetone (meth) acrylamide, dimethylaminoethyl (meth) acrylate, Diethylaminoethyl (meth) acrylate, lauryl (meth) acrylate, dicyclopentadiene (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopente (Meth) acrylate, N, N-dimethyl (meth) acrylamide tetrachlorophenyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, tetrabromophenyl (meth) acrylate, tribromophenyl (meth) acrylate, 2-hydroxyethyl (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, vinylcaprolactam, N-vinylpyrrolidone, butoxyethyl (meth) acrylate, pentachlorophenyl (meth) acrylate, pentabromophenyl (meth) acrylate, polyethylene glycol mono (meth) Acrylate, polypropylene glycol mono (meth) acrylate, isobornyl (meth) acrylate, methyltriethylene diglycol (meth) acrylate, Enoxyethyl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, 2-phenylphenoxyethyl (meth) acrylate, 4- Phenylphenoxyethyl (meth) acrylate, 3- (2-phenylphenyl) -2-hydroxypropyl (meth) acrylate, (meth) acrylate of p-cumylphenol reacted with ethylene oxide, 2-bromophenoxyethyl (meth) Acrylate, 4-bromophenoxyethyl (meth) acrylate, 2,4-dibromophenoxyethyl (meth) acrylate, 2,6-dibromophenoxyethyl (meth) acrylate, 2,4,6-tribromo Examples include phenyl (meth) acrylate and 2,4,6-tribromophenoxyethyl (meth) acrylate. These compounds having one ethylenically unsaturated bond group can be used singly or in combination of two or more.

  Examples of the compound having two or more ethylenically unsaturated bond groups include ethylene glycol di (meth) acrylate, dicyclopentenyl di (meth) acrylate, triethylene glycol diacrylate, tetraethylene glycol di (meth) acrylate, triethylene glycol Cyclodecanediyldimethylene di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, caprolactone-modified tris (2-hydroxyethyl) isocyanate Nurate tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) Acrylate, tripropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, pentaerythritol tri (meth) Acrylate, pentaerythritol tetra (meth) acrylate, polyester di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) Acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol penta (meth) acrylate, di Limethylolpropane tetra (meth) acrylate, (meth) acrylate of phenol novolac polyglycidyl ether, ethylene oxide-added bisphenol A (meth) acrylate, ethylene oxide-added tetrabromobisphenol A (meth) acrylate, propylene oxide-added bisphenol A ( (Meth) acrylic acid ester, propylene oxide-added tetrabromobisphenol A (meth) acrylic acid ester, bisphenol A epoxy (meth) acrylate obtained by epoxy ring-opening reaction of bisphenol A diglycidyl ether and (meth) acrylic acid, tetrabromo Tetrabromobisphenol A epoxy obtained by epoxy ring-opening reaction between bisphenol A diglycidyl ether and (meth) acrylic acid ( Epoxy ring-opening of bisphenol F epoxy (meth) acrylate, tetrabromobisphenol F diglycidyl ether and (meth) acrylic acid obtained by epoxy ring-opening reaction of (meth) acrylate, bisphenol F diglycidyl ether and (meth) acrylic acid And tetrabromobisphenol F epoxy (meth) acrylate obtained by the reaction. These compounds having two or more ethylenically unsaturated bonding groups can be used singly or in combination of two or more.

  Among these radical polymerizable compounds, from the viewpoint of curability of the curable composition, a combination of a compound having one or more ethylenically unsaturated bond groups and a compound having two or more ethylenically unsaturated bond groups is good, Further, from the viewpoint of curability of the curable composition, (meth) acrylates having an alicyclic structure such as tricyclodecanediyldimethylene di (meth) acrylate and isoboronyl (meth) acrylate are preferable.

Examples of the cationically polymerizable compound include vinyl ethers.
Specific examples of monofunctional compounds among vinyl ethers include, for example, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, n-pentyl vinyl ether, i-pentyl vinyl ether, t-pentyl vinyl ether, n-hexyl vinyl ether. I-hexyl vinyl ether, t-hexyl vinyl ether, cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, n-heptyl vinyl ether, i-heptyl vinyl ether, t-heptyl vinyl ether, octyl vinyl ether, nonyl vinyl ether, decyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, Alkyl vinyl ethers such as 2-ethylhexyl vinyl ether;
Aromatic vinyl ethers having an aromatic hydrocarbon group such as phenyl, benzyl, o-cresyl, p-cresyl, p-chlorophenyl, α-naphthyl, β-naphthyl in the molecule;

α-substituted vinyl ethers such as α-methyl vinyl ethyl ether, α-ethyl vinyl ethyl ether, α-phenyl vinyl ethyl ether;
β-substituted vinyl ethers such as β-methyl vinyl ethyl ether, β-methyl vinyl isopropyl ether, β-methyl vinyl n-butyl ether, β-methyl vinyl isobutyl ether, β-methyl vinyl t-butyl ether;

  3-methyl-3- (vinyloxymethyl) oxetane, 3-ethyl-3- (vinyloxymethyl) oxetane, 3-propyl-3- (vinyloxymethyl) oxetane, 3-methyl-3- (2-vinyloxy Ethyl) oxetane, 3-ethyl-3- (2-vinyloxyethyl) oxetane, 3-propyl-3- (2-vinyloxyethyl) oxetane, 3-methyl-3- (3-vinyloxypropyl) oxetane, 3 -Ethyl-3- (3-vinyloxypropyl) oxetane, 3-propyl-3- (3-vinyloxypropyl) oxetane, 3-methyl-3- (3-vinyloxybutyl) oxetane, 3-ethyl-3- (3-vinyloxybutyl) oxetane, 3-propyl-3- (3-vinyloxybutyl) oxetane, ethylene glycol [(3-ethyl-3-oxetanyl) methyl] ether, propylene glycol [(3-ethyl-3-oxetanyl) methyl] oxetane ring-containing vinyl ethers such as vinyl ether.

  Examples of the bifunctional compound having two functional groups in the molecule include polyethylene glycol divinyl ether, 1,4-cyclosan divinyl ether, 1,4-cyclohexane diallyl ether, 1,4-diethylcyclohexyl divinyl ether, 1,8 -Octane divinyl ether, 1,8-octane diallyl ether, trimethylolpropane divinyl ether, isosorbite divinyl ether, oxonorbornene divinyl ether, 1,4-butanediol divinyl ether, nonanediol divinyl ether, diethylene glycol divinyl ether, chiliethylene glycol Divinyl ethers such as divinyl ether and cyclohexane methanol divinyl ether; bisphenol-A divinyl ether, bisphenol-F di Vinyl ether, there is an aromatic divinyl ethers such as 1,3-benzene dimethyl ether.

  Examples of the compound containing a trifunctional or higher functional vinyl ether in the molecule include trivinyl ethers (trifunctional) such as trimethylolpropane trivinyl ether, pentaerythritol trivinyl ether, and trimethylolpropane trivinyl ether; tetratetrales such as pentaerythritol tetravinyl ether. Examples include vinyl ethers (tetrafunctional); pentavinyl ethers (pentafunctional) such as dipentaerythritol pentavinyl ether; hexavinyl ethers (hexafunctional) such as dipentaerythritol hexavinyl ether, and the like.

  Commercially available vinyl ethers include 2-hydroxyethyl vinyl ether (HEVE), diethylene glycol monovinyl ether (DEGV), 2-hydroxybutyl vinyl ether (HBVE), triethylene glycol divinyl ether (manufactured by Maruzen Petrochemical Co., Ltd.), RAPI- CURE series, V-PYROLR (N-Vinyl-2-Pyrrolidone), V-CAPTM (N-Vinyl-2-Caprolactam) (above, manufactured by ISP), and the like are available.

2. Organic solvent (B)
The organic solvent (B) is an organic solvent whose relative evaporation rate measured in accordance with ASTM-D3539 under the conditions of 25 ° C. and 1 atm is in the range of 1 to 15 when the value of butyl acetate is 1. It is a solvent. By containing an appropriate amount of the organic solvent (B), a composition excellent in releasability can be obtained.
The relative evaporation rates of various solvents are described in Table 5 on page 17-19 of “Latest Coating Technology” (published by General Technology Center, 1983). Specifically, alcohols such as methanol (1.9), ethanol (1.54), isopropanol (1.5), acetone (5.6), methyl ethyl ketone (3.7), methyl isobutol ketone A ketone solvent such as (1.6), an ether solvent such as tetrahydrofuran (8), ethyl acetate (6.1), and isobutyl acetate (1.5) are preferred. Of these, alcohol solvents, ketone solvents and the like are particularly preferably used.
(B) The content rate of a component is 0.01-10 weight part with respect to 100 weight part of (A) component, Preferably it is 0.1-10 weight part. By using the component (B) at this content ratio, a composition having no pattern roughness and excellent releasability can be obtained.

3. Initiator (C)
In the composition of the present invention, the initiator (C) activates the polymerizable group of the compound (A) by exposure to induce a curing reaction of the composition of the present invention.

  Examples of the initiator (C) include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2,2′-azobisisobutyronitrile, 2,2′- Azobis- (2,4-dimethylvaleronitrile), 2,2′-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis- (2-methylbutyronitrile), 1 , 1'-azobis- (cyclohexane-1-carbonitrile), dimethyl-2,2'-azobis (2-methylpropionate) and the like; benzoyl peroxide, lauroyl peroxide, tert-butylperoxypivalate, 1 , 1'-bis- (tert-butylperoxy) cyclohexane, and other organic peroxides and hydrogen peroxide. Moreover, when using an organic peroxide as an initiator (C), it is good also as a redox type initiator combining a reducing agent.

  In addition to these photopolymerization initiators, for example, biimidazole compounds described in JP 2007-293306 A, oxime type radical generators, benzoin compounds, acetophenone described in JP 2008-89744 A, for example. Compounds, benzophenone compounds, α-diketone compounds, polynuclear quinone compounds, xanthone compounds, phosphine compounds, triazine compounds, and diazo compounds and triazine compounds described in JP-A-2006-259680 are used. be able to.

  The content of the initiator (C) is preferably 1 to 30% by mass, more preferably 1 to 20% by mass, and further preferably 1 to 10% by mass. When the content exceeds 30% by mass, the storage stability tends to deteriorate, for example, foreign matter is generated. On the other hand, if it is less than 1% by mass, the pattern forming layer may be insufficiently cured.

  Here, “light” includes not only light having a wavelength in the ultraviolet, near-ultraviolet, far-ultraviolet, visible, infrared, and the like, and electromagnetic waves, but also radiation. This radiation includes, for example, microwaves, electron beams, EUV, X-rays and the like. Laser light such as a 248 nm excimer laser, a 193 nm excimer laser, and a 172 nm excimer laser can also be used. The light may be monochromatic light (single wavelength light) that has passed through an optical filter, or may be light having a plurality of different wavelengths (composite light). The exposure can be multiple exposure, and the entire surface can be exposed after forming a pattern for the purpose of increasing the film strength and etching resistance.

5 Other components Moreover, the curable composition for nanoimprint lithography of the present invention comprises a mold release agent, a silane coupling agent, an antioxidant, an ultraviolet absorber, a light stabilizer, an anti-aging agent, a plasticizer, an adhesion promoter, You may contain a coloring agent, an inorganic particle, an elastomer particle, antioxidant, a photo-acid multiplication agent, a photobase generator, a basic compound, a flow regulator, an antifoamer, a dispersing agent, etc.

(Release agent)
Examples of the release agent include conventionally known release agents such as silicone release agents, solid waxes such as polyethylene wax, amide wax, and tetrafluoroethylene powder, fluorine-based and phosphate ester-based compounds.

  The silicone release agent is a release agent having an organopolysiloxane structure as a basic structure, and examples thereof include unmodified or modified silicone oil, polysiloxane containing trimethylsiloxysilicic acid, and silicone acrylic resin.

  The content of the release agent is preferably 0.001 to 10% by mass and more preferably 0.01 to 5% by mass with respect to 100% by mass of the curable composition for nanoimprint lithography. If it is less than 0.01% by mass, the effect of containing a release agent may not be sufficient. On the other hand, if it exceeds 10 mass%, film peeling may occur during shape transfer.

(Silane coupling agent)
Examples of the silane coupling agent include vinyl silanes such as vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, and vinyltrimethoxysilane; γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyl Acrylic silanes such as dimethoxysilane; epoxy silanes such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane; N-β -(Aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxy Aminosilanes such as silane; .gamma.-mercaptopropyltrimethoxysilane, .gamma.-chloropropyl methyl dimethoxy silane, a .gamma.-chloropropyl methyl diethoxy silane.

  It is preferable that the content rate of a silane coupling agent is 0.001-10 mass% with respect to 100 mass% of curable compositions for nanoimprint lithography. If it is less than 0.001% by mass, the effect of containing a silane coupling agent may not be sufficient. On the other hand, if it exceeds 10% by mass, the stability and film formability of the curable composition for nanoimprint lithography may be inferior.

(Antioxidant)
Commercially available antioxidants include, for example, Irganox 1010, 1035, 1076, 1222 (above, manufactured by Ciba Geigy), Antigene P, 3C, FR, Sumilyzer S (above, manufactured by Sumitomo Chemical Co., Ltd.), etc. There is. It is preferable that the content rate of antioxidant is 0.01-10 mass% with respect to 100 mass% of curable compositions for nanoimprint lithography.

(UV absorber)
Examples of commercially available ultraviolet absorbers include Tinuvin P, 234, 320, 326, 327, 328, 213 (manufactured by Ciba Geigy), Sumisorb 110, 130, 140, 220, 250, 300, 320, 340, 350, 400 (above, manufactured by Sumitomo Chemical Co., Ltd.). It is preferable that the content rate of a ultraviolet absorber is 0.01-10 mass% with respect to 100 mass% of curable compositions for nanoimprint lithography.

II Pattern Forming Method The pattern forming method of the present invention comprises a step (1) of forming a shaped transfer layer comprising the curable composition for nanoimprint lithography described in “I curable composition for nanoimprint lithography” (hereinafter referred to as “covered material”). (Also referred to as “shape transfer layer forming step”), a step (2) in which the stamper is pressed against the shape transfer layer (hereinafter also referred to as “pressure contact step”), and a step in which the shape transfer layer is exposed with the stamper being pressed ( 3) (hereinafter also referred to as “exposure step”) and a step (4) (hereinafter also referred to as “peeling step”) of peeling the stamper from the shape-transferred layer. In addition, the method of further including the process (5) (henceforth an "etching process") which etches after a peeling process is preferable.

1 Step (1)
The shape transfer layer forming step is a step of forming the shape transfer layer on the substrate using the curable composition for nanoimprint lithography. FIG. 1 is a schematic diagram showing an example of a state after a shape transfer layer is formed on a substrate. The shape transfer layer forming step is a step of forming the shape transfer layer 2 on the substrate 1 as shown in FIG.

  As the substrate, a silicon wafer is usually used, but it is also known as a substrate for semiconductor devices such as aluminum, titanium-tungsten alloy, aluminum-silicon alloy, aluminum-copper-silicon alloy, silicon oxide, and silicon nitride. It can be used by arbitrarily selecting from things.

  The component which comprises a to-be-shaped transfer layer is the curable composition for nanoimprint lithography as described in "I curable composition for nanoimprint lithography." In addition to the curable composition for nanoimprint lithography, the shape transfer layer can contain a curing accelerator. Examples of the curing accelerator include a radiation-sensitive curing accelerator and a thermosetting accelerator. Among these, a radiation sensitive curing accelerator is preferable. A radiation sensitive hardening accelerator can be suitably selected according to the structural unit which comprises the curable composition for nanoimprint lithography. Specific examples include a photoacid generator, a photobase generator, a photo radical generator, and a photosensitizer. In addition, a radiation sensitive hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type.

  The curable composition for nanoimprint lithography is, for example, by inkjet method, dip coating method, air knife coating method, curtain coating method, wire barcode method, gravure coating method, extrusion coating method, spin coating method, slit scanning method, etc. The shape transfer layer can be formed by coating. In addition, although the film thickness of a to-be-shaped transfer layer changes with applications to be used, it is 0.01-5.0 micrometers, for example.

2 Step (2)
The pressure contact process is a process of pressing the stamper to the shape transfer layer. FIG. 2 is a schematic view showing an example of a state in which a stamper is pressed against the shape transfer layer. As shown in FIG. 2, the concave / convex pattern of the stamper 3 is formed in the shaped transfer layer 2 by pressing the stamper 3 against the shaped transfer layer 2 formed in step (1).

  For example, the stamper needs to be made of a light-transmitting material. Specific examples include light-transparent resins such as glass, quartz, PMMA, and polycarbonate resin, transparent metal vapor-deposited films, flexible films such as polydimethylsiloxane, photocured films, and metal films.

  The pressure at the time of pressure welding is not particularly limited, but is usually 0.1 to 100 MPa, preferably 0.1 to 50 MPa, more preferably 0.1 to 30 MPa, and 0.1 to 20 MPa. More preferably it is. In addition, the pressure contact time is not particularly limited, but is usually 1 to 600 seconds, preferably 1 to 300 seconds, more preferably 1 to 180 seconds, and particularly preferably 1 to 120 seconds. preferable.

3 Step (3)
The exposure step is a step of exposing the shape transfer layer while keeping the stamper in pressure contact. FIG. 3 is a schematic diagram showing an example of a state in which the shape transfer layer is exposed while the stamper is pressed. As shown in FIG. 3, when the shape transfer layer 3 is exposed, gas is generated from the gas generating agent (A) contained in the curable composition for nanoimprint lithography, and when the stamper 2 is peeled off, a film is formed. Peeling is less likely to occur or the uneven pattern of the stamper 2 is transferred to the shape transfer layer 3. By transferring the concavo-convex pattern, it can be used as, for example, a film for an interlayer insulating film of a semiconductor element such as LSI, system LSI, DRAM, SDRAM, RDRAM, or D-RDRAM, a resist film when manufacturing the semiconductor element, and the like. .

  The exposure source is not particularly limited. For example, radiation (including ArF excimer laser (wavelength 193 nm) or KrF excimer laser (wavelength 248 nm)) such as UV light, visible light, ultraviolet light, far ultraviolet light, X-rays, and electron beam charged particle beams is used. it can. Further, the exposure may be performed on the entire surface of the shape-transferring layer, or may be performed only on a partial region.

  Moreover, when the to-be-shaped transfer layer has thermosetting properties, heat curing may be further performed. When thermosetting is performed, the heating atmosphere and the heating temperature are not particularly limited. For example, heating can be performed at 40 to 200 ° C. under an inert atmosphere or under reduced pressure. Heating can be performed using a hot plate, an oven, a furnace, or the like.

4 Step (4)
The peeling step is a step of peeling the stamper 3 from the shape transfer layer 2. FIG. 4 is a schematic diagram illustrating an example of a state after the stamper is peeled from the shape transfer layer. The peeling process may be performed in any manner, and various conditions for peeling are not particularly limited. That is, for example, the substrate 1 may be fixed and the stamper may be moved away from the substrate 1 and separated, or the stamper may be fixed and the substrate 1 moved away from the stamper and separated. Both may be peeled by pulling in the opposite direction.

  In the imprint method of the present invention, since the curable composition for nanoimprint lithography of the present invention is used, gas is generated from the shape transfer layer by exposure in the step (3). Therefore, it is possible to suppress the adhesion between the stamper and the shape transfer layer after exposure from being reduced and film peeling.

  In the imprinting method of the present invention, a release agent can be used. That is, a release agent attaching step for attaching a release agent to the surface of the stamper having the concave / convex pattern may be performed before the press contact step.

  When using a release agent, the type is not particularly limited. For example, a silicon release agent, a fluorine release agent, a polyethylene release agent, a polypropylene release agent, a paraffin release agent, a montan release agent. There are mold agents, carnauba release agents, and the like. In addition, a mold release agent may be used individually by 1 type, and may be used in combination of 2 or more type. Among these, a silicon release agent is particularly preferable. Specific examples of the silicon release agent include polydimethylsiloxane, acrylic silicone graft polymer, acrylic siloxane, and arylsiloxane.

5 Step (5)
The etching step is a step of removing the remaining concave portion of the shape transfer layer by etching. FIG. 5 is a schematic diagram illustrating an example of a state after etching. As shown in FIG. 5, by performing an etching process, an unnecessary portion can be removed from the pattern shape of the shape transfer layer, and a desired resist pattern 10 can be formed.

It does not specifically limit as an etching method, It can form by performing a conventionally well-known method, for example, dry etching. A conventionally known dry etching apparatus can be used for the dry etching. The source gas at the time of dry etching is appropriately selected according to the elemental composition of the film to be etched, but includes an oxygen atom gas such as O ₂ , CO, CO ₂ , an inert gas such as He, N ₂ , Ar, A chlorine-based gas such as Cl ₂ or BCl ₃ , a gas of H ₂ or NH ₃ , or the like can be used. In addition, these gases can also be mixed and used.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values and the evaluation method of various characteristics are shown below.

  [Viscosity (mPa · s)]: Viscosity at 25 ° C. was measured using an E-type viscometer (manufactured by TOKMIC).

  [Evaluation of releasability]: The cross-sectional shape was observed with a scanning electron microscope (S-4200, manufactured by Hitachi High-Technologies Corporation), and the case where the pattern angle was around 85 degrees with a 350 nm line width was evaluated as “good”. Otherwise, it was evaluated as “bad”.

Example 1
As compound (A), 50 parts of 1,9-nonanediol diacrylate, 10 parts of tricyclodecane dimethanol acrylate and 40 parts of isobornyl acrylate, 0.1 part of tetrahydrofuran as organic solvent (B), and initiator As (C), 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (represented by the following formula (C-1)) 7.5 parts of 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propane (compound represented by the following formula (C-2)) is mixed. Thus, a curable composition for nanoimprint lithography was prepared.

  First, using a coater / developer (trade name “CLEAN TRACK ACT8”, manufactured by Tokyo Electron Ltd.), an organic underlayer film (trade name “NFC CT08”, manufactured by JSR Corp.) having a film thickness of 300 nm on the surface of an 8-inch silicon wafer Formed. Next, an inorganic intermediate film (trade name “NFC SOG08”, manufactured by JSR Corporation) having a film thickness of 45 nm was formed, and then divided into four to obtain experimental substrates. Thereafter, about 50 μL of the curable composition for nanoimprint lithography prepared in Example 1 was spotted on the center of the experimental substrate and placed on the work stage of a simple imprint apparatus (EUN-4200, manufactured by Engineering System). On the other hand, a quartz template (NIM-PH350, manufactured by NTT-ATN) coated with a release agent (trade name “HD-1100Z”, manufactured by Daikin Kasei Co., Ltd.) in advance by a predetermined method is used as a silicone rubber (thickness 0.2 mm). ) As an adhesive layer and attached to a quartz exposure head of a simple imprint apparatus. Next, after setting the pressure of the simple imprint apparatus to 0.2 MPa, the exposure head is lowered, the template and the experimental substrate are brought into close contact with each other via the photocurable composition for nanoimprint lithography, and then UV exposure is performed for 15 seconds. Carried out. After 15 seconds, the exposure stage was raised, and the template was peeled off from the cured shape transfer layer to form a pattern. There was no resist film residue on the template, and the evaluation of releasability was “good”.

(Examples 2-9 and Comparative Examples 1-3)
A curable composition for nanoimprint lithography was prepared in the same manner as in Example 1 except that the type and addition amount of the organic solvent (B) shown in Table 1 were used, and evaluated in the same manner as in Example 1. The results are shown in Table 1.

  The curable composition for nanoimprint lithography of the present invention can be suitably used for nanoimprint lithography used for improving the degree of integration and recording density of circuits such as semiconductor elements.

1: substrate, 2: shape transfer layer, 3: stamper, 4: light, 5: shape transfer layer, 10: resist pattern.

Claims (5)

  (A) a polymerizable compound, and (B) a relative evaporation rate measured in accordance with ASTM-D3539 under the conditions of 25 ° C. and 1 atm, the range of 1 to 15 when the value of butyl acetate is 1. A curable composition for nanoimprint lithography, comprising an organic solvent contained therein and 0.01 to 10 parts by weight of component (B) with respect to 100 parts by weight of component (A).   2. The curable composition for nanoimprint lithography according to claim 1, wherein the content of the component (B) is 0.1 to 1 part by weight with respect to 100 parts by weight of the component (A).   The curable composition for nanoimprint lithography according to claim 1, wherein the component (B) is at least one solvent selected from alcohol-based and ketone-based solvents.   The curable composition for nanoimprint lithography according to any one of claims 1 to 3, further comprising (C) a photopolymerization initiator. A step (1) of forming a shaped transfer layer comprising the curable composition for nanoimprint lithography according to any one of claims 1 to 4;
A step (2) of pressing a stamper on the shape transfer layer;
Exposing the shape-transfer layer while the stamper is in pressure contact with (3);
A step (4) of separating the stamper from the shape transfer layer;
A pattern forming method including:

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