WO2012157433A1 - ダブルパターン形成方法 - Google Patents
ダブルパターン形成方法 Download PDFInfo
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- WO2012157433A1 WO2012157433A1 PCT/JP2012/061287 JP2012061287W WO2012157433A1 WO 2012157433 A1 WO2012157433 A1 WO 2012157433A1 JP 2012061287 W JP2012061287 W JP 2012061287W WO 2012157433 A1 WO2012157433 A1 WO 2012157433A1
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/20—Exposure; Apparatus therefor
- G03F7/2022—Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
- H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
- H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
- H01L21/0274—Photolithographic processes
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/0035—Multiple processes, e.g. applying a further resist layer on an already in a previously step, processed pattern or textured surface
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/0045—Photosensitive materials with organic non-macromolecular light-sensitive compounds not otherwise provided for, e.g. dissolution inhibitors
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/039—Macromolecular compounds which are photodegradable, e.g. positive electron resists
- G03F7/0392—Macromolecular compounds which are photodegradable, e.g. positive electron resists the macromolecular compound being present in a chemically amplified positive photoresist composition
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/039—Macromolecular compounds which are photodegradable, e.g. positive electron resists
- G03F7/0392—Macromolecular compounds which are photodegradable, e.g. positive electron resists the macromolecular compound being present in a chemically amplified positive photoresist composition
- G03F7/0397—Macromolecular compounds which are photodegradable, e.g. positive electron resists the macromolecular compound being present in a chemically amplified positive photoresist composition the macromolecular compound having an alicyclic moiety in a side chain
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
- G03F7/30—Imagewise removal using liquid means
- G03F7/32—Liquid compositions therefor, e.g. developers
- G03F7/322—Aqueous alkaline compositions
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
- G03F7/30—Imagewise removal using liquid means
- G03F7/32—Liquid compositions therefor, e.g. developers
- G03F7/325—Non-aqueous compositions
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/26—Processing photosensitive materials; Apparatus therefor
- G03F7/40—Treatment after imagewise removal, e.g. baking
Definitions
- the present invention relates to a double pattern forming method.
- the first resist pattern when the first resist pattern is actually formed, the first resist pattern may be deformed or dissolved due to the influence of the solvent contained in the photoresist composition or exposure, resulting in a large difference in pattern height.
- the pattern cross-sectional shape is not rectangular.
- Another disadvantage is that it is difficult to form a pattern in which wide portions are mixed.
- the second resist pattern is a negative resist composition containing an alcohol-based organic solvent.
- a technique of using a material has been studied. However, even if these techniques are used, the above inconvenience cannot be sufficiently solved.
- the present invention has been made based on the above circumstances, and its purpose is a double pattern forming method capable of forming a resist pattern having a small pattern height difference, an excellent pattern cross-sectional shape, and a wide and narrow width. Is to provide.
- the invention made to solve the above problems is (1a) forming a first resist film on a substrate using the first photoresist composition; (1b) a step of exposing the first resist film; and (1c) a step of forming a first resist pattern including a step of developing the exposed first resist film using a first developer; and (2a) ) Applying a second photoresist composition to at least a space portion of the first resist pattern to form a second resist film; (2b) a step of exposing the second resist film, and (2c) a second resist pattern forming step including a step of developing the exposed second resist film using a second developer containing an organic solvent.
- the first resist pattern is insoluble or hardly soluble in the second developer.
- the first resist pattern to be formed is insoluble or hardly soluble in the organic solvent-containing developer in the second resist pattern forming step, so that the first resist pattern is formed when the second resist pattern is formed. It is possible to prevent the resist pattern from being deformed or dissolved. As a result, according to the double pattern formation method, it is possible to easily and reliably form a resist pattern having a small pattern height difference, excellent pattern cross-sectional shape, and wide and narrow width.
- the first developer is preferably a developer containing an organic solvent.
- the first developer as the specific developer, a relatively low-polarity portion of the first resist film can be removed, and a first resist pattern insoluble or hardly soluble in the second developer is formed. It can be formed easily.
- the first developer is an alkali developer
- the step of forming the first resist pattern is after the step (1c), (1d)
- the method further includes a step of exposing the developed first resist film.
- a developed first resist film is formed in which a relatively highly polar portion of the resist film is removed.
- the developed first resist By exposing the film, a first resist pattern insoluble or hardly soluble in the second developer can be easily formed.
- the first photoresist composition and the second photoresist composition are: [A] a polymer having an acid dissociable group that is dissociated by the action of an acid to generate an acid group (hereinafter, also referred to as “[A] polymer”); [B] It preferably contains an acid generator and [C] a solvent.
- the [A] polymer contained in the photoresist composition produces an acidic group such as a carboxyl group by dissociation of an acid-dissociable group by an acid generated from the [B] acid generator upon exposure, and the second development. It becomes insoluble or hardly soluble in the liquid. Therefore, the said double pattern formation method can be performed suitably by using the said photoresist composition.
- step (3) It is preferable to further include a step of bringing a basic compound into contact with the surface of the first resist film after development before the step (2a).
- the surface of the first resist film after development and the basic compound interact by further including the step (3), and as a result, the difference in pattern height is further increased. It is possible to form a resist pattern that is small, excellent in pattern cross-sectional shape, and wide and narrow in width.
- the first developer contains an organic solvent and the basic compound
- the step (3) is performed in the step (1c).
- the step of forming the first resist pattern includes the step (1c), (1c ′) further comprising a step of rinsing the developed first resist film with a rinsing liquid; It is also preferable that the rinse liquid contains the basic compound and the step (3) is performed in the step (1c ′).
- the second photoresist composition contains a basic compound and the step (3) is performed in the step (2a).
- the basicity of the basic compound is preferably larger than the basicity of the conjugate base of the acidic group generated by dissociation of the acid dissociable group of the polymer [A].
- the interaction between the surface of the first resist film after development and the basic compound becomes stronger.
- the pattern height difference of the double pattern, the pattern cross-sectional shape, and the width of the pattern can be further improved.
- Each of the first resist pattern and the second resist pattern is a line and space pattern,
- the line portions of the first resist pattern and the line portions of the second resist pattern are preferably arranged alternately.
- a line and space pattern with a narrower pitch can be suitably formed.
- Each of the first resist pattern and the second resist pattern is a line and space pattern, It is preferable that the line part of the first resist pattern and the line part of the second resist pattern are arranged orthogonally.
- a contact hole pattern with high resolution can be suitably formed.
- the double pattern forming method of the present invention it is possible to form a resist pattern having a small pattern height difference, excellent pattern cross-sectional shape, and wide and narrow width. Therefore, the present invention is suitable for fine processing by lithography.
- the double pattern forming method (A) includes a step of forming a first resist pattern and a step of forming a second resist pattern.
- the step of forming the first resist pattern includes steps (1a) to (1c), and the step of forming the second resist pattern includes steps (2a) to (2c).
- the double pattern formation method (A) has a (3) process, and may include the (1c ') process.
- Step (1a) is a step of forming the first resist film on the substrate using the first photoresist composition.
- the first photoresist composition is applied to the substrate 1 to form the first resist film 2 as shown in FIG.
- the solubility with respect to the developing solution of the resist film formed changes with exposure, it can be used, for example with respect to the developing solution containing an organic solvent by exposure.
- a conventionally known substrate such as a silicon wafer or a wafer coated with aluminum can be used. Further, for example, an organic or inorganic antireflection film may be formed on the substrate.
- the method for applying the first photoresist composition examples include spin coating, cast coating, and roll coating.
- the film thickness of the resist film to be formed is usually 10 nm to 1,000 nm, and preferably 10 nm to 500 nm.
- the solvent in the coating film may be volatilized by soft baking (SB) as necessary.
- the temperature of SB is appropriately selected depending on the composition of the photoresist composition to be used, but is usually 30 ° C. to 200 ° C., preferably 50 ° C. to 150 ° C.
- the SB time is usually 10 to 600 seconds, preferably 20 to 300 seconds.
- a protective film can be provided on the resist film.
- an immersion protective film can be provided on the resist film.
- Step (1b) is a step of exposing the first resist film.
- the exposure light 3 is applied to a desired region of the first resist film 2 formed in the step (1a) through a mask having a specific pattern and an immersion liquid as necessary.
- Exposure is performed by reducing projection or the like. For example, by performing reduction projection exposure through a mask having an isoline pattern in a desired region, an isotrench pattern can be formed as the first resist pattern.
- immersion liquid used in the case of immersion exposure.
- the immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a refractive index temperature coefficient as small as possible so as to minimize distortion of the optical image projected onto the film.
- the exposure light 3 is ArF excimer laser light (wavelength 193 nm)
- water is preferable and distilled water is more preferable from the viewpoints of availability and ease of handling.
- an additive that decreases the surface tension of the water and increases the surface activity may be added.
- the exposure light 3 is appropriately selected according to the type of acid generator and the like contained in the first photoresist composition.
- electromagnetic waves such as ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays, X-rays and ⁇ rays; And charged particle beams such as .alpha.
- far ultraviolet rays are preferable, ArF excimer laser light and KrF excimer laser light (wavelength 248 nm) are more preferable, and ArF excimer laser light is more preferable.
- the exposure conditions such as the exposure amount are appropriately selected according to the composition of the photoresist composition to be used, the type of additive, and the like.
- Exposure may be performed a plurality of times, and different exposure light 3 may be used for the plurality of exposures, but the first exposure light 3 is preferably ArF excimer laser light.
- PEB post-exposure baking
- Step (1c) is a step of developing the exposed first resist film using a first developer.
- the first resist pattern 4 is formed as shown in FIG.
- the first developer preferably contains an organic solvent.
- organic solvent examples include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.
- alcohol solvent examples include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol.
- ether solvent examples include dialiphatic ethers such as diethyl ether, dipropyl ether, and dibutyl ether; Diaromatic ethers such as diphenyl ether and ditolyl ether; And aromatic-aliphatic ethers such as anisole and phenylethyl ether.
- ketone solvent examples include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl amyl ketone, ethyl-n-butyl ketone, and methyl-n-hexyl ketone.
- Aliphatic ketone solvents such as, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, acetophenone; Aliphatic-aromatic ketone solvents such as acetophenone, propiophenone, tolyl methyl ketone; Aromatic ketone solvents such as benzophenone, tolylphenyl ketone, and ditolyl ketone are listed.
- amide solvent examples include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide. N-methylpropionamide, N-methylpyrrolidone and the like.
- ester solvent examples include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, and acetic acid.
- hydrocarbon solvents examples include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane , Aliphatic hydrocarbon solvents such as methylcyclohexane; Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.
- ether solvents an aromatic-aliphatic ether solvent is more preferable, and anisole is particularly preferable.
- ketone solvent an aliphatic ketone solvent is more preferable, and methyl amyl ketone is particularly preferable.
- ester solvent a monoester solvent is more preferable, and butyl acetate is particularly preferable. Two or more of these organic solvents may be used in combination.
- the content of the organic solvent in the first developer is preferably 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 90% by mass or more.
- a method of immersing the substrate in a tank filled with a developer for a certain period of time for example, a method of immersing the substrate in a tank filled with a developer for a certain period of time (dip method), a developer is raised on the surface of the substrate by surface tension, and is developed by standing for a certain period of time.
- Method paddle method
- spray method method of spraying developer on the substrate surface
- the developed resist pattern may be washed with a rinse solution and dried.
- a rinse liquid a liquid containing an organic solvent can be used, and the generated scum can be efficiently washed.
- the organic solvent contained include hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and the like. Of these, alcohol solvents and ester solvents are preferable, and monovalent alcohol solvents having 6 to 8 carbon atoms are more preferable.
- the rinsing liquid two or more kinds may be used in combination.
- the water content in the rinse liquid is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less. By setting the water content within the specific range, good development characteristics can be obtained.
- a surfactant can be added to the rinse liquid.
- a cleaning treatment method using a rinsing liquid for example, a method of continuously applying the rinsing liquid onto a substrate rotating at a constant speed (rotary coating method), or a method of immersing the substrate in a tank filled with the rinsing liquid for a certain period of time (Dip method), a method (spray method) of spraying a rinsing liquid on the substrate surface, and the like.
- Step (2a) is a step of forming a second resist film using the second photoresist composition in at least a space portion of the first resist pattern.
- the second photoresist composition is applied to at least the space portion of the first resist pattern 4 to form the second resist film 5.
- Step (2a) is the same as step (1a) above.
- the second photoresist composition may be the same as or different from the first photoresist composition in the step (1a). From the viewpoint of simplifying the double pattern formation process, it is preferable to use the same composition. Note that the same means that the types and blending amounts of all components in both compositions are the same, and that the two compositions are different means that the types of either component in both compositions or It means that the amount is different.
- the second photoresist composition in step (2a) may be applied only to the space portion of the first resist pattern 4 or may be applied to both the space portion of the first resist pattern 4 and the pattern.
- the film thickness of the second resist film 5 can be set independently regardless of the film thickness of the first resist film 2.
- Step (2b) is a step of exposing the second resist film.
- the second resist film 5 formed in the step (2a) is exposed by irradiation with exposure light 3.
- Step (2b) is the same as step (1b) above.
- Step (2c) is a step of developing the exposed second resist film using a second developer containing an organic solvent.
- Step (2c) is the same as step (1c) above.
- the second resist pattern 6 is formed.
- the second developer for example, an organic solvent-containing developer exemplified as the first developer in the step (1c) can be applied.
- the polarity of the second developer is preferably lower than the polarity of the first developer from the viewpoint of suppressing deformation, dissolution, etc. of the first resist pattern.
- the polarity of the developer is represented by, for example, a solubility parameter value (SP value).
- the first resist pattern is insoluble or hardly soluble in the second developer. Since the first resist pattern is insoluble or hardly soluble in the second developer, the first resist pattern is not deformed or dissolved when the second resist pattern is formed, and the formed double pattern has a good shape And can. Note that “insoluble or hardly soluble” means that the solubility in the developer is small enough to maintain the shape of the resist pattern substantially.
- the difference between the height of the second resist pattern 6 and the height of the first resist pattern 4 is the relationship between the film loss amount of the resist film 2 in the step (1c) and the film loss amount of the resist film 5 in the step (2c). Therefore, the appropriate film thickness of the resist film 5 can be calculated and adjusted. From the viewpoint of workability of the substrate after pattern formation, it is preferable that the height of the first resist pattern 4 and the height of the second resist pattern 6 are the same.
- the first developer is an alkali developer
- the step of forming the first resist pattern is performed after the step (1c) (1d)
- it differs from the double pattern formation method shown in FIG. 1 in that it further includes a step of exposing the first resist film after development.
- Step (1b) is a step of exposing the first resist film.
- the exposure light 3 is applied to a desired region of the first resist film 2 formed in the step (1a) through a mask having a specific pattern and an immersion liquid as necessary. Exposure is performed by reducing projection or the like. For example, by performing reduced projection exposure through a mask having an isoline pattern in a desired region, the isoline pattern can be formed as the first resist pattern.
- step (1c) of FIG. 2 development is performed using an alkaline developer as the first developer.
- an alkaline developer By using an alkaline developer, a portion having a relatively high polarity is dissolved and removed, and a developed first resist film 4 ′ is formed as shown in FIG. 2 (C ′).
- alkali developer examples include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine , Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3. 0] -5-Nonene and an alkaline aqueous solution in which at least one alkaline compound is dissolved.
- the concentration of the alkaline aqueous solution is usually 10% by mass or less. When the concentration of the alkaline aqueous solution exceeds 10% by mass, the unexposed area may be dissolved in the developer. In addition, after developing using aqueous alkali solution, it is preferable to wash and dry with water.
- alkaline developer examples include ketones such as acetone, methyl ethyl ketone, methyl i-butyl ketone, cyclopentanone, cyclohexanone, 3-methylcyclopentanone, 2,6-dimethylcyclohexanone, and acetonyl acetone; methyl alcohol, ethyl alcohol , N-propyl alcohol, i-propyl alcohol, n-butyl alcohol, t-butyl alcohol, cyclopentanol, cyclohexanol, 1,4-hexanediol, 1,4-hexanedimethylol and other alcohols; tetrahydrofuran, dioxane Ethers such as ethyl acetate, n-butyl acetate, and i-amyl acetate; aromatic hydrocarbons such as toluene and xylene; may contain two or more organic solvents such as phenol and di
- the content of the organic solvent is preferably 100 parts by volume or less, more preferably 50 parts by volume or less, particularly preferably 25 parts by volume or less, and most preferably 10 parts by volume or less with respect to 100 parts by volume of the alkaline developer.
- the addition amount of the organic solvent exceeds 100 parts by volume with respect to 100 parts by volume of the alkali developer, the alkali developability may be deteriorated and the development residue may be increased.
- An appropriate amount of a surfactant or the like can be added to the alkaline developer.
- Step (1d) is a step of exposing the developed first resist film.
- the first resist film 4 ′ after development is dissociated in the first resist film 4 ′ after the development due to the action of the acid generated by exposure.
- the first resist pattern 4 is insoluble or hardly soluble in the second developer containing the organic solvent.
- the exposure in the step (1d) is the same as the exposure in the step (1b). From the viewpoint of more reliably converting to the first resist pattern 4, the exposure is preferably all exposure including the space portion. Further, the exposure amount is not particularly limited as long as it is a sufficient exposure amount for conversion to the first resist pattern, and usually 0.01 to 0.1% of the exposure amount used in the step (1b). 10 times.
- the temperature of PEB is usually 30 ° C. to 200 ° C., preferably 50 ° C. to 170 ° C.
- the PEB time is usually 10 to 600 seconds, preferably 20 to 300 seconds.
- the shape of the double pattern obtained by the double pattern forming method is not particularly limited, the first resist pattern and the second resist pattern are each a line and space pattern, and the line portion of the first resist pattern and the second resist pattern It is preferable to arrange the line portions alternately. According to the double pattern forming method, a line and space pattern having a narrower pitch can be suitably formed.
- first resist pattern and the second resist pattern are line and space patterns, respectively, and the first resist pattern line portion and the second resist pattern line portion are arranged to be orthogonal to each other. According to the double pattern forming method, a high-resolution contact hole pattern or the like can be suitably formed.
- the same process as the second resist pattern formation process is further repeated a plurality of times on the substrate on which the first resist pattern and the second resist pattern are formed. You can also. By further performing the above steps, a resist pattern with higher resolution can be formed.
- the step (3) is a step of bringing a basic compound into contact with the surface of the developed first resist film before the step (2a).
- the double pattern forming method preferably further includes the step (3).
- the double pattern forming method is considered to further include the step (3), whereby the surface of the first resist film after development and the basic compound interact with each other. As a result, the pattern height difference is smaller, A resist pattern that is more excellent in cross-sectional shape and wider or narrower in width can be formed.
- the mode of performing the step (3) is not particularly limited as long as it is before the step (2a), and examples thereof include the following (3A) to (3C).
- the first developer contains an organic solvent and the basic compound, and the step (3) is performed in the step (1c).
- the double pattern formation method (A) the first resist after development generated in the step (1c) is obtained by using the organic solvent-containing developer which is the first developer and further containing a basic compound. A basic compound is brought into contact with the surface of the membrane.
- the step of forming the first resist pattern is after the step (1c), (1c ′) further comprising a step of rinsing the first resist film after the development using a rinsing liquid;
- the rinse liquid has the basic compound, and the step (3) is performed in the step (1c ′).
- the first resist film after development formed in the step (1c) is formed by rinsing with a rinse liquid containing a basic compound. A basic compound is brought into contact with the surface of the substrate.
- the second photoresist composition contains a basic compound, and the step (3) is performed in the step (2a).
- the basic compound is brought into contact with the surface of the first resist pattern, which is the first resist film after development, by using the second photoresist composition used in the step (2a) containing a basic compound.
- a nitrogen atom containing compound As said basic compound, a nitrogen atom containing compound, the compound containing the anion which has basicity, etc. are mentioned, for example.
- the nitrogen atom-containing compound include amine compounds, amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds.
- the basic anion include a hydroxyl anion, a carboxylate anion, a sulfonate anion, and a sulfonamide anion.
- Examples of the basic compound include compounds exemplified as the [E] acid diffusion controller of the photoresist composition described later.
- the basicity of the basic compound is preferably larger than the basicity of the acidic group generated by dissociation of the acid dissociable group of the polymer [A].
- the basicity of the basic compound is preferably greater than the basicity of the conjugate base of the acidic group, it is considered that the interaction between the surface of the first resist film after development and the basic compound becomes stronger.
- the acid group conjugate base is, for example, a —COO ⁇ E + group (E + is a counter anion) when the acid group is a —COOH group.
- the basicity of the basic compound and the conjugate base of the acidic group is represented by, for example, a base dissociation constant.
- Examples of the basic compound having a basicity greater than the conjugate base of the acidic group include, for example, when the acidic group is a carboxyl group, an amine compound, a nitrogen-containing heterocyclic compound, a compound containing a hydroxy anion, and a compound containing a carboxylate anion And compounds containing a sulfonamide anion.
- the acidic group is a carboxyl group
- an amine compound, a nitrogen-containing heterocyclic compound, a compound containing a hydroxy anion, and a compound containing a carboxylate anion And compounds containing a sulfonamide anion are preferred, tertiary amines, compounds containing cyclic amino groups, and compounds containing sulfonamide anions are more preferred.
- a trialkylamine, a compound having a piperidine ring, and an onium salt containing a sulfonamide anion are more preferable, 1,2,2,6,6-pentamethylpiperidin-4-ol, triphenylsulfonium Nn-butylsulfonamide Is particularly preferred.
- the content of the basic compound in the first developer is preferably 0.001% by mass to 10% by mass, more preferably 0.01% by mass to 8% by mass, and 0.1% by mass to 5% by mass. Is more preferable, and 0.3 to 3% by mass is particularly preferable.
- the content of the basic compound in the rinse liquid is preferably 0.001% by mass to 10% by mass, more preferably 0.01% by mass to 8% by mass, and 0.1% by mass to 5% by mass. More preferred is 0.3 to 3% by mass.
- the content of the basic compound in the second photoresist composition is preferably 0.01 parts by mass to 30 parts by mass with respect to 100 parts by mass of the polymer contained in the second photoresist composition. 0.05 to 15 parts by mass is more preferable, 0.1 to 10 parts by mass is further preferable, and 0.2 to 5 parts by mass is particularly preferable.
- the pattern height difference of the double pattern formed by the double pattern forming method can be further improved.
- the first photoresist composition and the second photoresist composition used in the double pattern forming method of the present invention are not particularly limited as long as the solubility of the formed resist film in a developing solution is changed by exposure.
- those that exhibit a decrease in solubility with respect to a developer containing an organic solvent and an increase in solubility with respect to an alkali developer due to exposure for example.
- Examples of the method for changing the solubility of the resist film in the developer by exposure include a method of containing a polymer whose polarity changes by exposure.
- the photoresist composition preferably contains [A] polymer, [B] acid generator and [C] solvent.
- the photoresist composition includes a polymer having a higher fluorine atom content than the [D] [A] polymer (hereinafter also referred to as “[D] polymer”), [E] acid diffusion controller. , [F] may contain additives.
- [D] polymer a polymer having a higher fluorine atom content than the [D] [A] polymer
- [E] acid diffusion controller [E] acid diffusion controller.
- [F] may contain additives.
- each component will be described in detail.
- the acid dissociable group that is dissociated by the action of an acid in the polymer to generate an acidic group is a group that replaces a hydrogen atom of an acidic group such as a carboxyl group or a hydroxyl group, and is exposed to [B ] A group dissociated by the action of an acid or the like generated from an acid generator.
- the photoresist composition includes a developer containing an organic solvent, because the [A] polymer has an acid-dissociable group, the acid-dissociable group in the exposed area is dissociated to generate an acidic group, and the polarity increases. The solubility in the alkaline developer is decreased and the solubility in the alkaline developer is increased.
- a [A] polymer contains the structural unit (I) containing an acid dissociable group.
- the polymer may contain a structural unit (II) having a lactone-containing group or a cyclic carbonate-containing group and a structural unit (III) having a hydrophilic functional group.
- the [A] polymer may contain 2 or more types of each structural unit.
- each structural unit will be described in detail.
- the structural unit (I) is a structural unit represented by the following formula (1).
- R ⁇ 1 > is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.
- R p is an acid dissociable group.
- the acid dissociable group represented by R p is preferably a group represented by the following formula (i).
- R p1 , R p2 and R p3 are each independently an alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms. However, R p2 and R p3 may be bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded.
- Examples of the alkyl group having 1 to 4 carbon atoms represented by R p1 , R p2 and R p3 include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and 2-methylpropyl. Group, 1-methylpropyl group, t-butyl group and the like.
- Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R p1 , R p2 and R p3 include a polycyclic alicyclic ring having a bridged skeleton such as an adamantane skeleton and a norbornane skeleton.
- These groups may be substituted with one or more of linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, for example.
- R p1 is an alkyl group having 1 to 4 carbon atoms
- R p2 and R p3 are bonded to each other, and a divalent group having an adamantane skeleton or a cycloalkane skeleton together with the carbon atom to which they are bonded. It is preferable to form.
- Examples of the structural unit (I) include structural units represented by the following formulas (1-1) to (1-4).
- R 1 has the same meaning as in the above formula (1).
- R p1 , R p2 and R p3 are as defined in the above formula (i).
- n p is an integer of 1 to 4.
- Examples of the structural unit represented by the above formula (1) or (1-1) to (1-4) include a structural unit represented by the following formula.
- R 1 is as defined in the above formula (1).
- Examples of the monomer that gives the structural unit (I) include (meth) acrylic acid 2-methyladamantyl-2-yl ester, (meth) acrylic acid 2-ethyladamantyl-2-yl ester, (meth) acrylic acid- 2-methylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-2-ethylbicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid 1- ( Bicyclo [2.2.1] hept-2-yl) -1-methylethyl ester, (meth) acrylic acid 1- (adamantan-1-yl) -1-methylethyl ester, (meth) acrylic acid 1-methyl -1-cyclopentyl ester, (meth) acrylic acid 1-ethyl-1-cyclopentyl ester, (meth) acrylic acid 1-methyl-1-cyclohexyl ester, ( Data), and acrylic acid 1-ethyl-1-cyclohexyl ester.
- the content ratio of the structural unit (I) in the [A] polymer is preferably 30 mol% to 70 mol% with respect to all the structural units constituting the [A] polymer.
- the polymer preferably contains a structural unit (II) containing a lactone-containing group or a cyclic carbonate-containing group.
- a lactone-containing group represents a cyclic group containing one ring (lactone ring) containing a —O—C (O) — structure.
- the cyclic carbonate-containing group refers to a cyclic group containing one ring (cyclic carbonate ring) containing a bond represented by —O—C (O) —O—.
- the lactone ring or cyclic carbonate ring is counted as the first ring, and if it has only a lactone ring or cyclic carbonate ring, it is called a monocyclic group, and if it has another ring structure, it is called a polycyclic group regardless of the structure. .
- Examples of the structural unit (II) include a structural unit represented by the following formula.
- R L1 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
- Examples of the monomer that gives the structural unit (II) include a monomer represented by the following formula (L-1).
- R L1 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
- R L2 is a single bond or a divalent linking group.
- R L3 is a monovalent organic group having a lactone structure or a cyclic carbonate structure.
- Examples of the divalent linking group represented by R L2 include a divalent linear or branched hydrocarbon group having 1 to 20 carbon atoms.
- Examples of the monovalent organic group having a lactone structure represented by R L3 include groups represented by the following formulas (L3-1) to (L3-6).
- Examples of the monovalent organic group having a cyclic carbonate structure include groups represented by the following formulas (L3-7) and (L3-8).
- R Lc1 is an oxygen atom or a methylene group.
- R Lc2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
- n Lc1 is 0 or 1.
- n Lc2 is an integer of 0 to 3.
- n C1 is an integer of 0-2.
- n C2 to n C5 are each independently an integer of 0 to 2.
- “*” Represents a site that binds to R L2 in the formula (L-1). Note that the groups represented by the formulas (L3-1) to (L3-8) may have a substituent.
- the content ratio of the structural unit (II) in the [A] polymer is preferably 30 mol% to 60 mol% with respect to all the structural units constituting the [A] polymer.
- the polymer may have a structural unit (III) having a hydrophilic functional group.
- the hydrophilic functional group include a hydroxyl group, an amino group, a ketonic carbonyl group, and a sulfonamide group.
- Examples of the structural unit (III) include a structural unit represented by the following formula.
- R 2 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
- the content ratio of the structural unit (III) in the [A] polymer is usually 30 mol% or less, preferably 0 mol% to 20 mol%, based on all structural units constituting the [A] polymer.
- the [A] polymer may further contain other structural units other than the structural units (I) to (III).
- other structural units include structural units containing a polar group such as a cyano group.
- Examples of the monomer that gives a structural unit containing a cyano group include 2-cyanomethyladamantyl (meth) acrylate and 2-cyanoethyl (meth) acrylate.
- the content ratio of other structural units in the [A] polymer is usually 30 mol% or less, preferably 0 mol% to 20 mol%, based on all the structural units constituting the [A] polymer.
- the polymer can be synthesized, for example, by polymerizing a monomer giving each structural unit in a suitable solvent using a radical polymerization initiator.
- radical polymerization initiators examples include 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis ( 2-cyclopropylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), azo radical initiators such as dimethyl 2,2′-azobisisobutyrate; benzoyl peroxide, t- And peroxide radical initiators such as butyl hydroperoxide and cumene hydroperoxide. Of these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred. Two or more of these radical initiators may be used.
- Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; cyclohexane, cycloheptane, cyclooctane, decalin, norbornane, etc.
- Cycloalkanes aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene; Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate; Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethanes and diethoxyethanes; Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. One or two or more of these solvents may be used.
- the reaction temperature in the above polymerization is usually 40 ° C to 150 ° C, preferably 50 ° C to 120 ° C.
- the reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.
- the weight average molecular weight (Mw) of the polymer by gel permeation chromatography (GPC) is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and 1,000 to 30. Is particularly preferred.
- Mw of a polymer By making Mw of a polymer into the above-mentioned specific range, the goodness of the cross-sectional shape of the formed double pattern can be improved. In addition, dry etching resistance can be improved.
- the ratio (Mw / Mn) of Mw and number average molecular weight (Mn) of the polymer is usually 1 to 3, preferably 1 to 2.
- Mw and Mn of the polymer were measured by GPC using GPC columns (2 "G2000HXL”, 1 "G3000HXL”, 1 "G4000HXL”) manufactured by Tosoh Corporation under the following conditions.
- Eluent Tetrahydrofuran (Wako Pure Chemical Industries)
- Flow rate 1.0 mL / min
- Sample concentration 1.0% by mass
- Sample injection volume 100 ⁇ L
- Detector Differential refractometer Standard material: Monodisperse polystyrene
- [B] Acid generator generates an acid upon exposure and changes the solubility of the [A] polymer in the developer by, for example, dissociating an acid dissociable group present in the [A] polymer with the acid. .
- the form of inclusion of the [B] acid generator in the photoresist composition even in the form of a low molecular compound as will be described later (hereinafter also referred to as “[B] acid generator” as appropriate) Either the built-in form or both forms may be used.
- Examples of the acid generator include onium salt compounds and N-sulfonyloxyimide compounds.
- onium salt compounds examples include sulfonium salts, tetrahydrothiophenium salts, and iodonium salts.
- sulfonium salt examples include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate, triphenylsulfonium camphorsulfonate, 4 -Cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate,
- tetrahydrothiophenium salt examples include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona.
- iodonium salt examples include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonate, diphenyliodonium camphorsulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium nonafluoro-n-butanesulfonate, Bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bic
- N-sulfonyloxyimide compounds include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy).
- the acid generator is preferably an onium salt compound, more preferably a sulfonium salt, and triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate, triphenylsulfonium. 2- (1-adamantyl) -1,1-difluoroethanesulfonate is particularly preferred.
- Two or more acid generators may be used.
- the content when the acid generator is an acid generator is usually 0.1 with respect to 100 parts by mass of the polymer [A] from the viewpoint of ensuring the sensitivity and developability of the photoresist composition. It is not less than 20 parts by mass and is preferably not less than 0.5 parts by mass and not more than 15 parts by mass. [B] If the content of the acid generator is less than the lower limit, the sensitivity and developability of the photoresist composition may be lowered. On the other hand, when the content of the [B] acid generator exceeds the above upper limit, the transparency to the exposure light is lowered and a desired resist pattern may not be obtained.
- a solvent will not be specifically limited if it is a solvent which can melt
- Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, and mixed solvents thereof.
- the solvent for example, the solvent exemplified as the organic solvent that can be contained in the first developer (developer in the step (1c)) can be applied.
- the solvent is preferably a ketone solvent or an ester solvent, more preferably an aliphatic ketone solvent, a polyhydric alcohol monoether acetate solvent or a lactone solvent, cyclohexanone, propylene glycol monomethyl ether acetate, ⁇ -butyrolactone. Is particularly preferred.
- the [C] solvent of the second photoresist composition is preferably one in which the first resist pattern is insoluble or hardly soluble.
- the first resist pattern is insoluble or hardly soluble in the second photoresist composition, it is possible to form a resist pattern having a smaller pattern height difference, better pattern cross-sectional shape, and wider and narrower width.
- the polymer is a polymer having a higher fluorine atom content than the [A] polymer.
- the distribution tends to be unevenly distributed on the surface of the resist film due to the oil-repellent characteristics of the [D] polymer when the resist film is formed.
- it can suppress that an acid generator, an acid diffusion control agent, etc. elute to an immersion medium, and is preferable.
- the water repellency characteristics of the [D] polymer due to the water repellency characteristics of the [D] polymer, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range, and the occurrence of bubble defects can be suppressed.
- the fluorine atom content (% by mass) can be calculated and obtained by measuring the polymer structure by measuring 13 C-NMR, 1 H-NMR, IR spectrum, or the like.
- the polymer is not particularly limited as long as the fluorine atom content is higher than that of the [A] polymer, but preferably has a fluorinated alkyl group.
- the polymer is formed by polymerization using at least one monomer containing a fluorine atom in the structure.
- Monomers that contain fluorine atoms in the structure include monomers that contain fluorine atoms in the main chain, monomers that contain fluorine atoms in the side chain, and monomers that contain fluorine atoms in the main chain and side chains. Can be mentioned.
- Examples of monomers containing a fluorine atom in the main chain include ⁇ -fluoroacrylate compounds, ⁇ -trifluoromethyl acrylate compounds, ⁇ -fluoroacrylate compounds, ⁇ -trifluoromethyl acrylate compounds, ⁇ , ⁇ -fluoroacrylate compounds, Examples include ⁇ , ⁇ -trifluoromethyl acrylate compounds, compounds in which hydrogen atoms at one or more types of vinyl sites are substituted with fluorine atoms or trifluoromethyl groups, and the like.
- Examples of the monomer containing a fluorine atom in the side chain include those in which the side chain of an alicyclic olefin compound such as norbornene is a fluorine atom or a fluoroalkyl group or a derivative thereof, a fluoroalkyl group of acrylic acid or methacrylic acid, or Examples thereof include an ester compound having such a derivative group, a monomer in which the side chain of one or more olefins (site not including a double bond) is a fluorine atom, a fluoroalkyl group or a derivative group thereof.
- Examples of the monomer containing fluorine atoms in the main chain and the side chain include ⁇ -fluoroacrylic acid, ⁇ -fluoroacrylic acid, ⁇ , ⁇ -fluoroacrylic acid, ⁇ -trifluoromethylacrylic acid, ⁇ -trifluoro Ester compound having a fluoroalkyl group such as methylacrylic acid, ⁇ , ⁇ -trifluoromethylacrylic acid or the like, or a derivative thereof, a compound in which hydrogen atoms of one or more kinds of vinyl sites are substituted with a fluorine atom or a trifluoromethyl group Monomer substituted with a fluorine atom or a fluoroalkyl group or a derivative thereof, a hydrogen atom bonded to a double bond of one or more alicyclic olefin compounds, a fluorine atom or a trifluoromethyl group, etc. And a monomer whose side chain is a fluoroalkyl group or a derivative group
- the polymer preferably contains a structural unit (IV) represented by the following formula.
- R 3 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
- R 4 is a linear or branched alkyl group having 1 to 6 carbon atoms having at least one fluorine atom, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof.
- k is an integer of 1 to 3. However, when R 4 is a plurality, may be a plurality of R 4 is optionally substituted by one or more identical.
- A is a single bond or a (k + 1) -valent linking group.
- Examples of the (k + 1) -valent linking group represented by A include an oxygen atom, sulfur atom, carbonyloxy group, oxycarbonyl group, amide group, sulfonylamide group, urethane group, carbonyloxy-di (oxycarbonyl) ethanediyl.
- Monomers that give structural unit (IV) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, Fluoro n-propyl (meth) acrylic acid ester, perfluoro i-propyl (meth) acrylic acid ester, perfluoro n-butyl (meth) acrylic acid ester, perfluoro i-butyl (meth) acrylic acid ester, perfluoro t -Butyl (meth) acrylic acid ester, 2- (1,1,1,3,3,3-hexafluoropropyl) (meth) acrylic acid ester, 1- (2,2,3,3,4,4,4) 5,5-octafluoropentyl) (meth) acrylic acid ester, perfluorocyclohexylmethyl (meth) acrylic Ester, 1- (2,2,3,3,3-pentafluoropropyl) (meth)
- the polymer may have two or more structural units (IV).
- a content rate of structural unit (IV) it is 5 mol% or more normally with respect to all the structural units in a [D] polymer, 10 mol% or more is preferable and 15 mol% or more is more preferable. If the content ratio of the structural unit (IV) is less than 5 mol%, a receding contact angle of 70 ° or more may not be achieved, and elution of an acid generator or the like from the resist film may not be suppressed.
- the polymer includes the structural unit (I) including an acid dissociable group, a lactone-containing group, or a cyclic carbonate-containing group in order to control the dissolution rate in the developer.
- the structural unit (II) and structural units having an alicyclic group may be contained.
- Examples of the structural unit containing the alicyclic group include a structural unit represented by the following formula (F2).
- R 5 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
- X is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms.
- Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by X include cyclobutane, cyclopentane, cyclohexane, bicyclo [2.2.1] heptane, bicyclo [2.2.2]. Octane, tricyclo [5.2.1.0 2,6 ] decane, tetracyclo [6.2.1.1 3,6 . And hydrocarbon groups composed of alicyclic rings derived from cycloalkanes such as 0 2,7 ] dodecane and tricyclo [3.3.1.1 3,7 ] decane.
- the content ratio of other structural units is usually 90 mol% or less and preferably 80 mol% or less with respect to all the structural units constituting the [D] polymer.
- the content of the [D] polymer in the photoresist composition is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the [A] polymer.
- [D] By making content of a polymer into the said specific range, the pattern formation property in the immersion exposure of a photoresist composition can be improved more. As a result, the shape of the obtained double pattern can be made better.
- the method for synthesizing the polymer can be synthesized, for example, according to the same method as the method for synthesizing the polymer [A].
- the Mw of the polymer is preferably 1,000 to 50,000, more preferably 1,000 to 30,000, and particularly preferably 1,000 to 10,000.
- Mw of the polymer is less than 1,000, a sufficient advancing contact angle may not be obtained.
- the acid diffusion controller controls the diffusion phenomenon in the resist film of the acid and the like generated from the [B] acid generator by exposure, and has an effect of suppressing an undesirable chemical reaction in the non-exposed region.
- the [E] acid diffusion controller has an effect of improving the storage stability of a photoresist composition containing the acid diffusion controller.
- the content of the acid diffusion controller in the photoresist composition was incorporated as part of the polymer even in the form of a free compound (hereinafter also referred to as “[E] acid diffusion controller” as appropriate). It may be in the form or both forms.
- Examples of the acid diffusion controller include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.
- Examples of the amine compound include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N, N ′, N′-tetra Methylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4,4′-diaminodiphenylamine, 2,2-bis (4 -Aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-amino) Phenyl) -2- (4-hydroxyphenyl) propane, 1 4-bis (1- (4-a
- amide group-containing compounds include Nt-butoxycarbonyl group-containing amino compounds such as N- (t-butoxycarbonyl) -4-hydroxypiperidine, and N- (t-pentyloxycarbonyl) -4-hydroxypiperidine.
- Nt-pentyloxycarbonyl group-containing amino compound formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methyl
- Examples include pyrrolidone, N-acetyl-1-adamantylamine, and isocyanuric acid tris (2-hydroxyethyl).
- urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea, etc. Is mentioned.
- nitrogen-containing heterocyclic compound examples include imidazoles; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 3-piperidino-1,2-propanediol, morpholine, 4- Methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2 ] Octane etc. are mentioned.
- a photodegradable base that is exposed to light and generates a weak acid upon exposure can also be used.
- the photodegradable base there is an onium salt compound that is decomposed by exposure and loses acid diffusion controllability.
- the onium salt compound include a sulfonium salt compound represented by the following formula (K1) and an iodonium salt compound represented by the following formula (K2).
- R 6 to R 10 are each independently a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, or a halogen atom.
- Z - and E - are, OH -, R A -COO - , R A -SO 3 -, R A -N - is an anion represented by -SO 2 -R B or formula (K3).
- RA is an alkyl group, an aryl group, or an alkaryl group.
- R B is an alkyl group which may have a fluorine atom.
- R 11 represents a linear or branched alkyl group having 1 to 12 carbon atoms in which part or all of hydrogen atoms may be substituted with fluorine atoms, or 1 to 12 carbon atoms. These are linear or branched alkoxy groups.
- u is an integer of 0-2.
- the content of the acid diffusion controller is preferably less than 5 parts by mass with respect to 100 parts by mass of the [A] polymer.
- the content of the acid diffusion controller exceeds 5 parts by mass, the sensitivity as a resist tends to decrease.
- the photoresist composition may contain, for example, a surfactant, a sensitizer and the like as the [F] additive.
- Surfactants have the effect of improving coatability, striation, developability, and the like.
- the same surfactants as those used for general photoresist compositions can be used.
- the sensitizer represents the action of increasing the amount of acid generated from the [B] acid generator, and has the effect of improving the “apparent sensitivity” of the photoresist composition.
- sensitizer examples include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines, and the like. Two or more of these sensitizers may be used in combination.
- the photoresist composition can be prepared, for example, by mixing [A] polymer, [B] acid generator, [C] solvent and a suitable component in a predetermined ratio.
- the total solid concentration of the photoresist composition is usually 1% by mass to 50% by mass, and preferably 1% by mass to 25% by mass.
- a monomer solution was prepared by dissolving 50 mol% of the compound (M-1), 50 mol% of the compound (M-4) and 2 mol% of AIBN as a polymerization initiator in 60 g of methyl ethyl ketone.
- the total mass of the monomer compounds was adjusted to 30 g.
- 30 g of methyl ethyl ketone was added to a 500 mL three-necked flask equipped with a thermometer and a dropping funnel, and a nitrogen barge was performed for 30 minutes. Then, it heated so that it might become 80 degreeC, stirring the inside of a flask with a magnetic stirrer.
- the monomer solution was dropped into the three-necked flask over 3 hours using a dropping funnel.
- the dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. Then, it cooled until it became 30 degrees C or less, and obtained the polymerization solution.
- This polymerization solution was put into 600 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice as a slurry with 120 g of methanol, filtered, and dried at 50 ° C. for 17 hours to obtain a white powdery polymer (A-1) (yield) : 23.5 g, yield: 78.3%).
- the content ratio (mol%) of the structural unit derived from the compound (M-1) to the structural unit derived from the compound (M-4) in the polymer (A-1) was 47.8. : 52.2.
- Mw of the polymer (A-1) was 11,800, and Mw / Mn was 1.60.
- JNM-EX400 manufactured by JEOL Ltd. was used, and DMSO-d 6 was used as a measurement solvent.
- the dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours.
- D-1 38.0 g in terms of solid content, yield 76.0%).
- the content ratio (mol%) of the structural unit derived from the compound (M-8) to the structural unit derived from the compound (M-9) in the polymer (D-1) was 70.2: 29.8.
- Mw of the polymer (D-1) was 7,000, and Mw / Mn was 1.40.
- E-1 N- (t-pentyloxycarbonyl) -4-hydroxypiperidine represented by the following formula (E-1)
- E-2 Triphenylsulfonium Nn represented by the following formula (E-2) -Butyl-trifluoromethylsulfonamide
- E-3 1,2,2,6,6-pentamethylpiperidin-4-ol represented by the following formula (E-3)
- [Preparation Example 1] [A] 100 parts by mass of the polymer (A-1) as a polymer, [B] 7.8 parts by mass of an acid generator (B-1) as an acid generator, [C] (C-1 as a solvent) 3,320 parts by weight, (C-2) 1,420 parts by weight and (C-3) 30 parts by weight, [D] 3 parts by weight of polymer (D-1) as a polymer, and [E] acid 1.0 parts by mass of (E-1) as a diffusion control agent was mixed to prepare a photoresist composition (J-1).
- a resist film having a film thickness of 60 nm was formed by cooling at 23 ° C. for 30 seconds.
- NSR-S610C ArF immersion exposure apparatus
- NA numerical aperture
- PEB PEB was performed at 85 ° C. for 60 seconds on the CLEAN TRACK Lithius Pro i hot plate, and then cooled at 23 ° C. for 30 seconds.
- paddle development was performed for 30 seconds using methyl amyl ketone (MAK) as a developing solution, followed by rinsing treatment for 7 seconds using 4-methyl-2-pentanol (MPL) as a rinsing solution. Thereafter, spin drying was performed by shaking off at 2,000 rpm for 15 seconds to obtain a first resist pattern having a 28 nm line / 112 nm pitch.
- MAK methyl amyl ketone
- MPL 4-methyl-2-pentanol
- Examples 2 to 17 Each double pattern was formed in the same manner as in Example 1 except that the photoresist compositions shown in Table 3 were used and the conditions were changed.
- BA represents butyl acetate
- ANS represents anisole
- MAK + represents 1% by mass of MAK containing the compound represented by the above formula (E-2).
- “-” in the table indicates that the corresponding operation was not performed.
- Example 12 ⁇ Double pattern formation method (B)> [Example 12]
- a resist film having a thickness of 60 nm was formed using the photoresist composition (J-1).
- exposure and PEB were performed under the same conditions as in Example 1, and then cooled.
- 2.38 mass% tetramethylammonium hydroxide aqueous solution (TMAH) was used as a developing solution, and paddle development was performed for 30 seconds, followed by rinsing treatment using water (ultra pure water) as a rinsing solution. Then, it spin-dried by shaking off at 2,000 rpm for 15 seconds.
- TMAH tetramethylammonium hydroxide aqueous solution
- PEB was performed at 85 ° C. for 60 seconds on a CLEAN TRACK Lithius Pro i hot plate, and then cooled at 23 ° C. for 30 seconds to obtain a first resist pattern having a 28 nm line / 112 nm pitch.
- the same operation as in Example 1 was performed to form a second resist pattern, and a double pattern of 28 nm line / 56 nm pitch was obtained.
- Example 13 A double pattern was obtained in the same manner as in Example 12 except that the photoresist composition used for forming the first and second resist patterns was (J-2).
- Example 1 In the same manner as in Example 12, the photoresist composition (J-1) was spin-coated to form a resist film having a thickness of 60 nm. Next, exposure, PEB (105 ° C. in Comparative Example 1), development, and rinsing were performed under the same conditions as in Example 12 using an ArF immersion exposure apparatus. Then, it spin-dried by shaking off at 2,000 rpm for 15 seconds. Thereafter, the pattern protective film material described in Example 88 of JP-A-2009-69817 was spin-coated using the CLEAN TRACK ACT12 so that the film thickness of the formed protective film was 120 nm, and the film was formed at 160 ° C. for 60 seconds. After baking, it was cooled at 23 ° C.
- a second resist pattern was formed in the same manner as in Example 1 except that a 2.38 mass% TMAH aqueous solution was used as the developer and water (ultra pure water) was used as the rinse liquid, and a second resist pattern was formed. A double pattern with a line / 56 nm pitch was obtained.
- Pattern height difference (nm) The exposure amount at which the portion exposed through the mask pattern of the 56 nm line and 112 nm pitch forms a line and space pattern of 28 nm line / 112 nm pitch was determined as the optimum exposure amount. At this optimum exposure amount, the cross-sectional shape of the formed line and space pattern was observed using a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies). The difference between the height of the first resist pattern and the height of the second resist pattern was measured and used as the pattern height difference (nm). The case where the pattern height difference was less than 20 nm was designated as “A” (determined as good), and the case where the pattern height difference was 20 nm or greater was designated as “B” (determined as defective).
- Pattern cross-sectional shape At the optimum exposure amount, the cross-sectional shape of the formed line and space pattern was observed with the scanning electron microscope. A case where the pattern cross-sectional shape is a rectangle was designated as “A” (determined as good), and a case where the pattern cross-sectional shape was not a rectangle, such as a shape with a mountain shape or a skirt, was designated as “B” (determined as defective).
- [Maximum curing dimension] As a resist pattern used for evaluation of the maximum cured dimension, a resist pattern obtained in the same manner as in the above example was prepared except that the exposure in forming the second resist pattern was not performed. On the other hand, in the case of the above comparative example, a light-sensitive material obtained in the same manner as in the above comparative example was prepared except that the entire resist was exposed with an exposure amount of 20 mJ / cm 2 as the exposure for forming the second resist pattern. By these preparations, the photoresist composition applied on the formed first resist pattern is removed by a developer used for development in the formation of the second resist pattern.
- an optimal exposure amount for forming a 42 nm line / 84 nm pitch was used as the exposure amount of exposure in the formation of the first resist pattern.
- a pitch of 500 nm, a line width of 42 nm, and 50 nm to 400 nm in increments of 10 nm were prepared by the same method.
- the formed resist pattern the presence of the first resist pattern when the second resist pattern formation process is performed is observed, and the line having the largest line width among the existing patterns without being damaged The width was the maximum cured dimension.
- the maximum curing dimension is larger, a double pattern in which wider portions are mixed can be suitably formed.
- the case where the maximum curing dimension was 300 nm or more was determined as “A” (determined as good), and the case where it was less than 300 nm was determined as “B” (determined as defective).
- the height of the first resist pattern and the second resist pattern to be formed can be made equal, and the cross-sectional shape of the pattern can be made rectangular. It was found that a double pattern having a good shape can be formed. In addition, the maximum cured dimension of the resist pattern to be formed can be increased, which is suitable for forming a resist pattern in which wide portions are mixed.
- the present invention there is provided a double pattern forming method capable of forming a resist pattern having a small pattern height difference, excellent pattern cross-sectional shape, and wide and narrow width. Therefore, the present invention is suitable for fine processing by lithography.
- first resist film 3 exposure light
- first resist pattern 4 ′ first resist film 5 after development: second resist film 6: second resist pattern 7: exposure light
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Abstract
Description
(1a)第1フォトレジスト組成物を用い、基板上に第1レジスト膜を形成する工程、
(1b)上記第1レジスト膜を露光する工程、及び
(1c)上記露光された第1レジスト膜を第1現像液を用いて現像する工程
を含む第1レジストパターンを形成する工程、並びに
(2a)上記第1レジストパターンの少なくともスペース部分に、第2フォトレジスト組成物を塗布し、第2レジスト膜を形成する工程、
(2b)上記第2レジスト膜を露光する工程、及び
(2c)上記露光された第2レジスト膜を、有機溶媒を含有する第2現像液を用いて現像する工程
を含む第2レジストパターン形成工程
を有し、
上記第1レジストパターンが、第2現像液に不溶又は難溶であるダブルパターン形成方法である。
上記第1レジストパターンを形成する工程が、(1c)工程の後に、
(1d)現像後の第1レジスト膜を露光する工程
をさらに含むことが好ましい。
[A]酸の作用により解離して酸性基を生成する酸解離性基を有する重合体(以下、「[A]重合体」とも称する)、
[B]酸発生体、及び
[C]溶媒
を含有することが好ましい。
をさらに有することが好ましい。
当該ダブルパターン形成方法によれば、上記(3)工程をさらに有することで、現像後の第1レジスト膜の表面と塩基性化合物とが相互作用すると考えられ、その結果、パターン高さ差がより小さく、パターン断面形状により優れ、かつ幅により広狭があるレジストパターンを形成することができる。
また、上記第1レジストパターンを形成する工程が、(1c)工程の後に、
(1c’)上記現像された第1レジスト膜をリンス液を用いてリンスする工程
をさらに有し、
上記リンス液が上記塩基性化合物を含有し、上記(3)工程を(1c’)工程において行うことも好ましい。
さらに、上記第2フォトレジスト組成物が塩基性化合物を含有し、上記(3)工程を(2a)工程において行うことも好ましい。
これらの工程において上記(3)工程を行うことで、上述の現像後の第1レジスト膜の表面と塩基性化合物とが効果的に相互作用し、その結果、ダブルパターンのパターン高さ差、パターン断面形状及びパターンの幅広さをより向上させることができる。
上記第1レジストパターンのライン部と第2レジストパターンのライン部とを交互に配置することが好ましい。
上記第1レジストパターンのライン部と第2レジストパターンのライン部とを直交して配置することが好ましい。
図1に示すように、ダブルパターン形成方法(A)は、第1レジストパターンを形成する工程、及び第2レジストパターンを形成する工程を有する。第1レジストパターンを形成する工程は、(1a)工程~(1c)工程を含み、第2レジストパターンを形成する工程は、(2a)工程~(2c)工程を含む。また、ダブルパターン形成方法(A)は、(3)工程を有することが好ましく、(1c’)工程等を含んでいてもよい。以下、各工程を詳述する。
(1a)工程は、第1フォトレジスト組成物を用い、基板上に第1レジスト膜を形成する工程である。ここでは、第1フォトレジスト組成物を基板1に塗布し、図1(A)に示すように第1レジスト膜2を形成する。上記第1フォトレジスト組成物としては、形成されるレジスト膜の現像液に対する溶解性が、露光により変化するものであれば用いることができ、例えば露光により、有機溶媒を含有する現像液に対しては溶解性が低下し、アルカリ現像液に対しては溶解性が増大する組成物等が挙げられる。
(1b)工程は、上記第1レジスト膜を露光する工程である。ここでは、図1(B)に示すように、(1a)工程で形成した第1レジスト膜2の所望の領域に特定パターンのマスク及び必要に応じて液浸液を介して、露光光3を縮小投影等することにより露光する。例えば所望の領域にアイソラインパターンを有するマスクを介して縮小投影露光を行うことにより、第1レジストパターンとしてアイソトレンチパターンを形成できる。
(1c)工程は、上記露光された第1レジスト膜を第1現像液を用いて現像する工程である。本工程により、図1(C)のように第1レジストパターン4が形成される。上記第1現像液は、有機溶媒を含有することが好ましい。上記第1現像液を上記特定の現像液とすることで、レジスト膜における極性の比較的低い部分を除去することができ、第2現像液に不溶又は難溶の第1レジストパターンを簡便に形成することができる。
メタノール、エタノール、n-プロパノール、iso-プロパノール、n-ブタノール、iso-ブタノール、sec-ブタノール、tert-ブタノール、n-ペンタノール、iso-ペンタノール、2-メチルブタノール、sec-ペンタノール、tert-ペンタノール、3-メトキシブタノール、n-ヘキサノール、2-メチルペンタノール、sec-ヘキサノール、2-エチルブタノール、sec-ヘプタノール、3-ヘプタノール、n-オクタノール、2-エチルヘキサノール、sec-オクタノール、n-ノニルアルコール、2,6-ジメチル-4-ヘプタノール、n-デカノール、sec-ウンデシルアルコール、トリメチルノニルアルコール、sec-テトラデシルアルコール、sec-ヘプタデシルアルコール、フルフリルアルコール、フェノール、シクロヘキサノール、メチルシクロヘキサノール、3,3,5-トリメチルシクロヘキサノール、ベンジルアルコール、ジアセトンアルコール等のモノアルコール系溶媒;
エチレングリコール、1,2-プロピレングリコール、1,3-ブチレングリコール、2,4-ペンタンジオール、2-メチル-2,4-ペンタンジオール、2,5-ヘキサンジオール、2,4-ヘプタンジオール、2-エチル-1,3-ヘキサンジオール、ジエチレングリコール、ジプロピレングリコール、トリエチレングリコール、トリプロピレングリコール等の多価アルコール系溶媒;
エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノプロピルエーテル、エチレングリコールモノブチルエーテル、エチレングリコールモノヘキシルエーテル、エチレングリコールモノフェニルエーテル、エチレングリコールモノ-2-エチルブチルエーテル、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノプロピルエーテル、ジエチレングリコールモノブチルエーテル、ジエチレングリコールモノヘキシルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、プロピレングリコールモノプロピルエーテル、プロピレングリコールモノブチルエーテル、ジプロピレングリコールモノメチルエーテル、ジプロピレングリコールモノエチルエーテル、ジプロピレングリコールモノプロピルエーテル等の多価アルコール部分エーテル系溶媒等が挙げられる。
ジエチルエーテル、ジプロピルエーテル、ジブチルエーテル等のジ脂肪族エーテル;
ジフェニルエーテル、ジトリルエーテル等のジ芳香族エーテル;
アニソール、フェニルエチルエーテル等の芳香族-脂肪族エーテル等が挙げられる。
アセトン、メチルエチルケトン、メチル-n-プロピルケトン、メチル-n-ブチルケトン、ジエチルケトン、メチル-iso-ブチルケトン、メチルアミルケトン、エチル-n-ブチルケトン、メチル-n-ヘキシルケトン、ジ-iso-ブチルケトン、トリメチルノナノン、シクロペンタノン、シクロヘキサノン、シクロヘプタノン、シクロオクタノン、メチルシクロヘキサノン、2,4-ペンタンジオン、アセトニルアセトン、アセトフェノン等の脂肪族ケトン系溶媒;
アセトフェノン、プロピオフェノン、トリルメチルケトン等の脂肪族-芳香族ケトン系溶媒;
ベンゾフェノン、トリルフェニルケトン、ジトリルケトン等の芳香族ケトン系溶媒等が挙げられる。
N,N’-ジメチルイミダゾリジノン、N-メチルホルムアミド、N,N-ジメチルホルムアミド、N,N-ジエチルホルムアミド、アセトアミド、N-メチルアセトアミド、N,N-ジメチルアセトアミド、N-メチルプロピオンアミド、N-メチルピロリドン等が挙げられる。
酢酸メチル、酢酸エチル、酢酸n-プロピル、酢酸iso-プロピル、酢酸n-ブチル、酢酸iso-ブチル、酢酸sec-ブチル、酢酸n-ペンチル、酢酸sec-ペンチル、酢酸3-メトキシブチル、酢酸メチルペンチル、酢酸2-エチルブチル、酢酸2-エチルヘキシル、酢酸ベンジル、酢酸シクロヘキシル、酢酸メチルシクロヘキシル、酢酸n-ノニル、アセト酢酸メチル、アセト酢酸エチル、酢酸メトキシトリグリコール、プロピオン酸エチル、プロピオン酸n-ブチル、プロピオン酸iso-アミル、乳酸メチル、乳酸エチル、乳酸n-ブチル、乳酸n-アミル等のモノエステル系溶媒;
ジ酢酸グリコール、シュウ酸ジエチル、シュウ酸ジ-n-ブチル、マロン酸ジエチル、フタル酸ジメチル、フタル酸ジエチル等のジエステル系溶媒;
エチレングリコールモノメチルエーテルアセテート、エチレングリコールモノエチルエーテルアセテート、ジエチレングリコールモノメチルエーテルアセテート、ジエチレングリコールモノエチルエーテルアセテート、ジエチレングリコールモノ-n-ブチルエーテルアセテート、プロピレングリコールモノメチルエーテルアセテート、プロピレングリコールモノエチルエーテルアセテート、プロピレングリコールモノプロピルエーテルアセテート、プロピレングリコールモノブチルエーテルアセテート、ジプロピレングリコールモノメチルエーテルアセテート、ジプロピレングリコールモノエチルエーテルアセテート等の多価アルコールモノエーテルアセテート系溶媒;
γ-ブチロラクトン、γ-バレロラクトン等のラクトン系溶媒;
ジエチルカーボネート、ジプロピルカーボネート、エチレンカーボネート、プロピレンカーボネート等のカーボネート系溶媒等が挙げられる。
n-ペンタン、iso-ペンタン、n-ヘキサン、iso-ヘキサン、n-ヘプタン、iso-ヘプタン、2,2,4-トリメチルペンタン、n-オクタン、iso-オクタン、シクロヘキサン、メチルシクロヘキサン等の脂肪族炭化水素系溶媒;
ベンゼン、トルエン、キシレン、メシチレン、エチルベンゼン、トリメチルベンゼン、メチルエチルベンゼン、n-プロピルベンゼン、iso-プロピルベンゼン、ジエチルベンゼン、iso-ブチルベンゼン、トリエチルベンゼン、ジ-iso-プロピルベンセン、n-アミルナフタレン等の芳香族炭化水素系溶媒等が挙げられる。
(1c)工程の後に、(1c’)工程として、現像後のレジストパターンをリンス液により洗浄して乾燥してもよい。このリンス液としては、有機溶媒を含有する液を使用することができ、発生したスカムを効率よく洗浄することができる。含有される有機溶媒としては、炭化水素系溶媒、ケトン系溶媒、エステル系溶媒、アルコール系溶媒、アミド系溶媒等が挙げられる。これらのうち、アルコール系溶媒、エステル系溶媒が好ましく、炭素数6~8の1価のアルコール系溶媒がより好ましい。
(2a)工程は、上記第1レジストパターンの少なくともスペース部分に、第2フォトレジスト組成物を用い、第2レジスト膜を形成する工程である。ここでは、図1(D)に示すように、第1レジストパターン4の少なくともスペース部分に、第2フォトレジスト組成物を塗布し、第2レジスト膜5を形成する。(2a)工程は、上記(1a)工程と同様である。上記第2フォトレジスト組成物は、(1a)工程の第1フォトレジスト組成物と同一であってもよく、異なっていてもよい。ダブルパターン形成のプロセスを簡便とする観点から、同一の組成物を用いることが好ましい。なお、同一であるとは、両組成物中の全ての成分の種類及び配合量が同一であることを意味し、両組成物が異なるとは、両組成物中のいずれかの成分の種類又は配合量が異なることを意味する。
(2b)工程は、上記第2レジスト膜を露光する工程である。ここでは、図1(E)に示すように、(2a)工程で形成した第2レジスト膜5を露光光3の照射により露光する。(2b)工程は、上記(1b)工程と同様である。
(2c)工程は、上記露光された第2レジスト膜を、有機溶媒を含有する第2現像液を用いて現像する工程である。(2c)工程は、上記(1c)工程と同様である。本工程により、図1(F)に示すように、第2レジストパターン6が形成される。上記第2現像液としては、例えば(1c)工程において第1現像液として例示した有機溶媒含有現像液等が適用できる。ダブルパターン形成方法(A)において、第2現像液の極性は、上記第1現像液の極性より低いことが第1レジストパターンの変形、溶解等を抑える観点から好ましい。なお、現像液の極性は、例えば溶解度パラメーター値(SP値)等により表される。
図2に示すように、ダブルパターン形成方法(B)は、上記第1現像液が、アルカリ現像液であり、上記第1レジストパターンを形成する工程が、(1c)工程の後に、(1d)現像後の第1レジスト膜を露光する工程をさらに含む点で図1に示すダブルパターン形成方法とは異なる。以下、異なる工程について詳述する。
(1b)工程は、上記第1レジスト膜を露光する工程である。ここでは、図2(B)に示すように、(1a)工程で形成した第1レジスト膜2の所望の領域に特定パターンのマスク及び必要に応じて液浸液を介して、露光光3を縮小投影等することにより露光する。例えば所望の領域にアイソラインパターンを有するマスクを介して縮小投影露光を行うことにより、第1レジストパターンとしてアイソラインパターンを形成できる。
図2の(1c)工程では、上記第1現像液としてアルカリ現像液を用いて現像する。アルカリ現像液を用いることで、極性が比較的高い部分が溶解、除去され、図2(C’)に示すように現像後の第1レジスト膜4’が形成される。
(1d)工程は、現像後の第1レジスト膜を露光する工程である。本工程により、図2(C’’)に示すように、露光によって発生した酸の作用により、現像後の第1レジスト膜4’は、構成する重合体の酸解離性基が解離して極性基を生じること等により、有機溶媒を含有する第2現像液に不溶又は難溶な第1レジストパターン4に転換される。
(3)工程は、上記(2a)工程以前に、現像後の第1レジスト膜の表面に塩基性化合物を接触させる工程である。当該ダブルパターン形成方法においては、(3)工程をさらに有することが好ましい。当該ダブルパターン形成方法は、(3)工程をさらに有することで、現像後の第1レジスト膜の表面と塩基性化合物とが相互作用すると考えられ、その結果、パターン高さ差がより小さく、パターン断面形状により優れ、かつ幅により広狭があるレジストパターンを形成することができる。
(1c’)上記現像後の第1レジスト膜をリンス液を用いてリンスする工程
をさらに有し、
上記リンス液が上記塩基性化合物を有し、上記(3)工程を(1c’)工程において行う。ここでは、ダブルパターン形成方法(A)において、(1c)工程の後に、塩基性化合物を含有したリンス液を用いてリンスすることにより、(1c)工程で形成された現像後の第1レジスト膜の表面に塩基性化合物を接触させる。
上記窒素原子含有化合物としては、例えば、アミン化合物、アミド基含有化合物、ウレア化合物、含窒素複素環化合物等が挙げられる。
上記塩基性を有するアニオンとしては、ヒドロキシルアニオン、カルボキシレートアニオン、スルホネートアニオン、スルホンアミドアニオン等が挙げられる。
本発明のダブルパターン形成方法に用いる上記第1フォトレジスト組成物及び第2フォトレジスト組成物は、形成されるレジスト膜の現像液に対する溶解性が、露光により変化するものであれば特に限定されず、例えば露光により、有機溶媒を含有する現像液に対しては溶解性が低下し、アルカリ現像液に対しては溶解性が上昇するもの等が挙げられる。レジスト膜の現像液に対する溶解性を露光により変化させる方法としては、例えば露光により極性が変化する重合体を含有させる方法等が挙げられる。
[A]重合体が有する酸の作用により解離して酸性基を生成する酸解離性基とは、カルボキシル基、ヒドロキシル基等の酸性基の水素原子を置換する基であって、露光により[B]酸発生体から発生する酸等の作用により解離する基をいう。フォトレジスト組成物は、[A]重合体が酸解離性基を有することで、露光部における酸解離性基が解離して酸性基が生成して極性が増大し、有機溶媒を含有する現像液に対する溶解度が減少し、アルカリ現像液に対する溶解度が増大する。酸解離性基を有する態様としては、[A]重合体が酸解離性基を含む構造単位(I)を含むことが好ましい。また、[A]重合体は、ラクトン含有基又は環状カーボネート含有基を含む構造単位(II)、親水性官能基を有する構造単位(III)を含んでいてもよい。なお、[A]重合体は、各構造単位を2種以上含んでいてもよい。以下、各構造単位を詳述する。
構造単位(I)は、下記式(1)で表される構造単位である。
[A]重合体は、ラクトン含有基又は環状カーボネート含有基を含む構造単位(II)を含むことが好ましい。[A]重合体が構造単位(II)を有することで、形成されるレジストパターンの基板への密着性、及びレジストパターン同士の密着性を向上できる。ラクトン含有基とは、-O-C(O)-構造を含むひとつの環(ラクトン環)を含有する環式基を表す。また、環状カーボネート含有基とは、-O-C(O)-O-で表される結合を含むひとつの環(環状カーボネート環)を含有する環式基を表す。ラクトン環又は環状カーボネート環を1つめの環として数え、ラクトン環又は環状カーボネート環のみの場合は単環式基、さらに他の環構造を有する場合は、その構造に関わらず多環式基と称する。
[A]重合体は、親水性官能基を有する構造単位(III)を有してもよい。[A]重合体が構造単位(III)を有することで、第1レジストパターン及び第2レジストパターンの有機溶媒を含有する現像液に対する溶解耐性が向上する。結果として、得られるダブルパターンの形状をより良好にすることができる。親水性官能基としては、例えばヒドロキシル基、アミノ基、ケトン性カルボニル基、スルホンアミド基等が挙げられる。
[A]重合体は、例えば各構造単位を与える単量体を、ラジカル重合開始剤を使用し、適当な溶媒中で重合することにより合成することができる。
n-ペンタン、n-ヘキサン、n-ヘプタン、n-オクタン、n-ノナン、n-デカン等のアルカン類;シクロヘキサン、シクロヘプタン、シクロオクタン、デカリン、ノルボルナン等のシクロアルカン類;ベンゼン、トルエン、キシレン、エチルベンゼン、クメン等の芳香族炭化水素類;
クロロブタン類、ブロモヘキサン類、ジクロロエタン類、ヘキサメチレンジブロミド、クロロベンゼン等のハロゲン化炭化水素類;
酢酸エチル、酢酸n-ブチル、酢酸i-ブチル、プロピオン酸メチル等の飽和カルボン酸エステル類;
アセトン、メチルエチルケトン、4-メチル-2-ペンタノン、2-ヘプタノン等のケトン類;テトラヒドロフラン、ジメトキシエタン類、ジエトキシエタン類等のエーテル類;
メタノール、エタノール、1-プロパノール、2-プロパノール、4-メチル-2-ペンタノール等のアルコール類等が挙げられる。これらの溶媒は、1種又は2種以上を用いてもよい。
溶離液:テトラヒドロフラン(和光純薬工業製)
流量:1.0mL/分
試料濃度:1.0質量%
試料注入量:100μL
検出器:示差屈折計
標準物質:単分散ポリスチレン
[B]酸発生体は、露光により酸を発生し、その酸により[A]重合体中に存在する酸解離性基を解離させる等により、[A]重合体の現像液に対する溶解度を変化させる。フォトレジスト組成物における[B]酸発生体の含有形態としては、後述するような低分子化合物の形態(以下、適宜「[B]酸発生剤」とも称する)でも、酸発生基として重合体に組み込まれた形態でも、これらの両方の形態でもよい。
[C]溶媒は、[A]重合体、[B]酸発生体及び好適成分を溶解できる溶媒であれば特に限定されない。[C]溶媒としては、例えばアルコール系溶媒、エーテル系溶媒、ケトン系溶媒、アミド系溶媒、エステル系溶媒及びその混合溶媒等が挙げられる。
[D]重合体は、[A]重合体よりフッ素原子含有率が高い重合体である。上記フォトレジスト組成物が[D]重合体を含有することで、レジスト膜を形成した際に[D]重合体の撥油性的特徴により、その分布がレジスト膜表層に偏在化する傾向がある。結果として、液浸露光を行う場合、酸発生剤や酸拡散制御剤等が液浸媒体に溶出することを抑制でき好ましい。また、この[D]重合体の撥水性的特徴により、レジスト膜と液浸媒体との前進接触角が所望の範囲に制御でき、バブル欠陥の発生を抑制できる。さらに、レジスト膜と液浸媒体との後退接触角が高くなり、水滴が残らずに高速でのスキャン露光が可能となる。なお、フッ素原子含有率(質量%)は、重合体の構造を13C-NMR、1H-NMR、IRスペクトル等を測定することにより求め、算出することができる。
[D]重合体の合成方法としては、例えば[A]重合体の合成方法と同様の方法に従って合成することができる。[D]重合体のMwとしては、1,000~50,000が好ましく、1,000~30,000がより好ましく、1,000~10,000が特に好ましい。[D]重合体のMwが1,000未満の場合、十分な前進接触角を得ることができない場合がある。
[E]酸拡散制御体は、露光により[B]酸発生体から発生する酸等のレジスト膜中における拡散現象を制御し、非露光領域における好ましくない化学反応を抑制する効果を奏する。また、[E]酸拡散制御体は、これを含有するフォトレジスト組成物の貯蔵安定性を向上させる効果も奏する。[E]酸拡散制御体のフォトレジスト組成物における含有形態としては、遊離の化合物の形態(以下、適宜「[E]酸拡散制御剤」とも称する)でも、重合体の一部として組み込まれた形態でも、これらの両方の形態でもよい。
フォトレジスト組成物は、[F]添加剤として、例えば界面活性剤、増感剤等を含有していてもよい。
界面活性剤は、塗布性、ストリエーション、現像性等を改良する効果を奏する。界面活性剤としては、一般的なフォトレジスト組成物に用いられるものと同様のものを用いることができる。
増感剤は、[B]酸発生体からの酸の生成量を増加する作用を表すものであり、フォトレジスト組成物の「みかけの感度」を向上させる効果を奏する。
フォトレジスト組成物は、例えば[A]重合体、[B]酸発生体、[C]溶媒及び好適成分を所定の割合で混合することにより調製できる。フォトレジスト組成物の全固形分濃度としては、通常、1質量%~50質量%であり、1質量%~25質量%が好ましい。
[A]重合体及び[D]重合体の合成に用いた単量体を以下に示す。
上記化合物(M-1)50モル%、化合物(M-4)50モル%及び重合開始剤としてのAIBN2モル%を60gのメチルエチルケトンに溶解した単量体溶液を準備した。また、単量体化合物の合計質量は30gになるように調整した。一方、温度計及び滴下漏斗を備えた500mLの三口フラスコにメチルエチルケトン30gを加え、30分間窒素バージを行った。その後、フラスコ内をマグネティックスターラーで攪拌しながら、80℃になるように加熱した。次いで、上記単量体溶液を三口フラスコ内に滴下漏斗を用いて3時間かけて滴下した。滴下開始を重合反応の開始時間とし、重合反応を6時間実施した。その後、30℃以下になるまで冷却して重合溶液を得た。この重合溶液を600gのメタノール中へ投入し、析出した白色粉末をろ別した。ろ別した白色粉末を2回、120gずつのメタノールでスラリー状にして洗浄した後、ろ別し、50℃で17時間乾燥し、白色粉末状の重合体(A-1)を得た(収量:23.5g、収率:78.3%)。13C-NMR分析の結果、重合体(A-1)における化合物(M-1)由来の構造単位:化合物(M-4)由来の構造単位の含有割合(モル%)は、それぞれ47.8:52.2であった。重合体(A-1)のMwは11,800、Mw/Mnは、1.60であった。13C-NMR分析は、日本電子製「JNM-EX400」を使用し、測定溶媒としてDMSO-d6を使用して分析を行った。
表1に示す種類及び仕込み量の単量体を用いたこと以外は、合成例1と同様に操作して各重合体を合成した。得られた重合体の各構造単位の含有割合、各重合体のMw、Mw/Mn、及び収率を表1に合わせて示す。なお、表1の「-」は、該当する構造単位を与える単量体を用いなかったことを示す。
上記化合物(M-8)35.8g(70モル%)、化合物(M-9)14.2g(30モル%)及び重合開始剤としてのジメチル2,2’-アゾビスイソブチレート3.2g(8モル%)を100gのメチルエチルケトンに溶解し、単量体溶液を調製した。100gのメチルエチルケトンを入れた500mL三口フラスコを30分窒素パージした後、撹拌しながら80℃に加熱し、上記単量体溶液を滴下漏斗にて3時間かけて滴下した。滴下開始を重合反応の開始時間とし、重合反応を6時間実施した。重合反応終了後、重合反応液を水冷して30℃以下に冷却し、メタノール/メチルエチルケトン/ヘキサン=2/1/8(質量比)の混合溶液825gを用いて洗浄した後、プロピレングリコールモノメチルエーテルアセテートで溶媒置換し、重合体(D-1)を含む溶液を得た(固形分換算で38.0g、収率76.0%)。13C-NMR分析の結果、重合体(D-1)における化合物(M-8)由来の構造単位:化合物(M-9)由来の構造単位の含有比率(モル%)は、70.2:29.8であった。重合体(D-1)のMwは、7,000、Mw/Mnは、1.40であった。
単量体化合物として、化合物(M-1)27.3g(70モル%)及び化合物(M-10)22.7g(30モル%)を用いた以外は、合成例5と同様に操作して、重合体(D-2)を含む溶液を得た(固形分換算で35.9g、収率71.7%)。13C-NMR分析の結果、重合体(D-2)における化合物(M-1)由来の構造単位:化合物(M-10)由来の構造単位の含有比率(モル%)は、67.9:32.1であった。重合体(D-2)のMwは、6,200、Mw/Mnは、1.52であった。
フォトレジスト組成物の調製に用いた各成分の詳細を以下に示す。
B-1:下記式(B-1)で表されるトリフェニルスルホニウム2-(ビシクロ[2.2.1]ヘプタン-2-イル)-1,1-ジフルオロエタンスルホネート
B-2:下記式(B-2)で表されるトリフェニルスルホニウム2-(1-アダマンチル)-1,1-ジフルオロエタンスルホネート
C-1:プロピレングリコールモノメチルエーテルアセテート
C-2:シクロヘキサノン
C-3:γ-ブチロラクトン
E-1:下記式(E-1)で表されるN-(t-ペンチルオキシカルボニル)-4-ヒドロキシピペリジン
E-2:下記式(E-2)で表されるトリフェニルスルホニウムN-n-ブチル-トリフルオロメチルスルホンアミド
E-3:下記式(E-3)で表される1,2,2,6,6-ペンタメチルピペリジン-4-オール
[A]重合体としての重合体(A-1)100質量部、[B]酸発生剤としての酸発生剤(B-1)7.8質量部、[C]溶媒としての(C-1)3,320質量部、(C-2)1,420質量部及び(C-3)30質量部、[D]重合体としての重合体(D-1)3質量部、並びに[E]酸拡散制御剤としての(E-1)1.0質量部を混合し、フォトレジスト組成物(J-1)を調製した。
表2に示す種類及び配合量の各成分を用いた以外は、調製例1と同様に操作して、各フォトレジスト組成物を調製した。
<ダブルパターン形成方法(A)>
[実施例1]
12インチシリコンウェハ上に、反射防止膜形成剤(ARC66、日産化学製)を、現像装置(CLEAN TRACK Lithius Pro i、東京エレクトロン製)を用いてスピンコートした後、205℃で60秒間ベークして、膜厚105nmの下層反射防止膜を形成した。この下層反射防止膜を形成した基板上に、現像装置(CLEAN TRACK ACT12、東京エレクトロン製)を用いて、フォトレジスト組成物(J-1)をスピンコートし、80℃で60秒間SBした後、23℃で30秒間冷却することにより膜厚60nmのレジスト膜を形成した。次いで、ArF液浸露光装置(NSR-S610C、ニコン精機カンパニー製)を用い、開口数(NA)=1.3、ダイポールXの光学条件にて、ラインアンドスペースパターンマスクを介して、28nmライン/112nmピッチのパターンが形成されるように縮小投影露光を行った。露光後、上記CLEAN TRACK Lithius Pro iのホットプレート上で、85℃で60秒間PEBを行った後、23℃で30秒間冷却させた。次に、現像液としてメチルアミルケトン(MAK)を用い、30秒間パドル現像を行い、続いてリンス液として4-メチル-2-ペンタノール(MPL)を用い、7秒間リンス処理を行った。その後、2,000rpm、15秒間振り切りでスピンドライすることにより、28nmライン/112nmピッチの第1レジストパターンを得た。
表3に示すフォトレジスト組成物を使用し、各条件としたこと以外は、実施例1と同様に操作して、各ダブルパターンを形成した。なお、表3中の現像液はBAは酢酸ブチルを示し、ANSはアニソールを示し、「MAK+」は1質量%の上記式(E-2)で表される化合物を含有するMAKを示す。また、表中の「-」は、該当する操作を行わなかったことを示す。
[実施例12]
実施例1と同様に操作して、フォトレジスト組成物(J-1)を用いて膜厚60nmのレジスト膜を形成した。次いで、上記ArF液浸露光装置を用い、実施例1と同条件で露光、PEBを行い冷却した。次に、現像液として2.38質量%テトラメチルアンモニウムヒドロキシド水溶液(TMAH)を用い、30秒間パドル現像を行い、続いてリンス液として水(超純水)を用いリンス処理を行った。その後、2,000rpm、15秒間振り切りでスピンドライした。その後、上記ArF液浸露光装置を用い、NA=1.3、ダイポールXの光学条件にてマスクを介さず、20mJ/cm2の露光量で全面露光を行った。露光後、CLEAN TRACK Lithius Pro iのホットプレート上で、85℃で60秒間PEBを行った後、23℃で30秒間冷却させることにより、28nmライン/112nmピッチの第1レジストパターンを得た。引き続き、実施例1と同様に操作して、第2レジストパターンを形成し、28nmライン/56nmピッチのダブルパターンが得られた。
第1及び第2レジストパターンの形成に用いるフォトレジスト組成物を(J-2)としたこと以外は、実施例12と同様に操作してダブルパターンを得た。
実施例12と同様に操作して、フォトレジスト組成物(J-1)をスピンコートし、膜厚60nmのレジスト膜を形成した。次いで、ArF液浸露光装置を用い実施例12と同条件で露光、PEB(但し比較例1では105℃)、現像、リンス処理を行った。その後、2,000rpm、15秒間振り切りでスピンドライした。その後、特開2009-69817の実施例88に記載のパターン保護膜材料を、上記CLEAN TRACK ACT12を用い、形成される保護膜の膜厚が120nmとなるようにスピンコートし、160℃で60秒間ベークした後、23℃で30秒間冷却させた。次いで、CLEAN TRACK Lithius Pro iにて、2.38質量%TMAH水溶液により30秒間パドル現像を行い、続いて、リンス液として水(超純水)を用い、リンス処理を行った。その後、2,000rpm、15秒間振り切りでスピンドライすることにより余分な保護膜を除去してから、160℃で60秒間ベークを行い、パターン表面をさらに架橋させ、第1レジストパターンを得た。
第1及び第2レジストパターンの形成に用いるフォトレジスト組成物を(J-3)としたこと以外は、比較例1と同様に操作してダブルパターンを得た。
形成した各ダブルパターンについて、以下の評価をした。結果を表3にあわせて示す。
56nmライン112nmピッチのマスクパターンを介して露光した部分が、28nmライン/112nmピッチのラインアンドスペースパターンを形成する露光量を、最適露光量とした。この最適露光量において、形成されたラインアンドスペースパターンの断面形状を、走査型電子顕微鏡(S-4800、日立ハイテクノロジーズ製)を用いて観察した。第1レジストパターンの高さと第2レジストパターンの高さの差を測定し、パターン高さ差(nm)とした。パターン高さ差が、20nm未満である場合を「A」(良好と判断)、20nm以上である場合を「B」(不良と判断)とした。
上記最適露光量において、形成されたラインアンドスペースパターンの断面形状を、上記走査型電子顕微鏡で観察した。パターン断面形状が矩形である場合を「A」(良好と判断)、山型や裾を引いた形状のように矩形でない場合を「B」(不良と判断)とした。
最大硬化寸法の評価に用いるレジストパターンとして、上記実施例において、第2レジストパターンの形成における露光を行わなかった以外は、上記実施例と同様にして得られるものを調製した。一方、上記比較例の場合は、第2レジストパターンの形成における露光として、露光量20mJ/cm2で全面露光を行った以外は、上記比較例と同様にして得られるものを調製した。これらの調製により、形成された第1レジストパターン上に塗布されたフォトレジスト組成物は、第2レジストパターンの形成における現像に用いる現像液により除去される。なお、第1レジストパターンの形成における露光の露光量としては、42nmライン/84nmピッチを形成するのに最適な露光量とした。また、評価に用いるレジストパターンとして、ピッチは500nmとし、ライン幅が42nm、及び50nmから400nmまで10nm刻みのものを、同様の方法によりそれぞれ調製した。形成したレジストパターンにおいて、第2レジストパターン形成の処理を施した場合の第1レジストパターンの存在状況を観察し、ダメージを受けずに存在しているパターンのうち、ライン幅が最大であるもののライン幅を最大硬化寸法とした。最大硬化寸法が大きいほど、より広い幅の部分が混在するダブルパターンでも好適に形成することができる。最大硬化寸法が300nm以上である場合を「A」(良好と判断)、300nm未満である場合を「B」(不良と判断)とした。
2 :第1レジスト膜
3 :露光光
4 :第1レジストパターン
4’:現像後の第1レジスト膜
5 :第2レジスト膜
6 :第2レジストパターン
7 :露光光
Claims (11)
- (1a)第1フォトレジスト組成物を用い、基板上に第1レジスト膜を形成する工程、
(1b)上記第1レジスト膜を露光する工程、及び
(1c)上記露光された第1レジスト膜を第1現像液を用いて現像する工程
を含む第1レジストパターンを形成する工程、並びに
(2a)上記第1レジストパターンの少なくともスペース部分に、第2フォトレジスト組成物を用い、第2レジスト膜を形成する工程、
(2b)上記第2レジスト膜を露光する工程、及び
(2c)上記露光された第2レジスト膜を、有機溶媒を含有する第2現像液を用いて現像する工程
を含む第2レジストパターンを形成する工程
を有し、
上記第1レジストパターンが、上記第2現像液に不溶又は難溶であるダブルパターン形成方法。 - 上記第1現像液が、有機溶媒を含有する現像液である請求項1に記載のダブルパターン形成方法。
- 上記第1現像液が、アルカリ現像液であり、
上記第1レジストパターンを形成する工程が、(1c)工程の後に、
(1d)現像後の第1レジスト膜を露光する工程
をさらに含む請求項1に記載のダブルパターン形成方法。 - 上記第1フォトレジスト組成物及び第2フォトレジスト組成物が、
[A]酸の作用により解離して酸性基を生成する酸解離性基を有する重合体、
[B]酸発生体、及び
[C]溶媒
を含有する請求項1、請求項2又は請求項3に記載のダブルパターン形成方法。 - (3)上記(2a)工程以前に、現像後の第1レジスト膜の表面に塩基性化合物を接触させる工程
をさらに有する請求項1から請求項4のいずれか1項に記載のダブルパターン形成方法。 - 上記第1現像液が有機溶媒及び上記塩基性化合物を含有し、上記(3)工程を(1c)工程において行う請求項5に記載のダブルパターン形成方法。
- 上記第1レジストパターンを形成する工程が、(1c)工程の後に、
(1c’)上記現像後の第1レジスト膜をリンス液を用いてリンスする工程
をさらに含み、
上記リンス液が上記塩基性化合物を含有し、上記(3)工程を(1c’)工程において行う請求項5に記載のダブルパターン形成方法。 - 上記第2フォトレジスト組成物が塩基性化合物を含有し、上記(3)工程を(2a)工程において行う請求項5に記載のダブルパターン形成方法。
- 上記塩基性化合物の塩基性度が、上記[A]重合体の酸解離性基の解離により生成する酸性基の共役塩基の塩基性度より大きい請求項5から請求項8のいずれか1項に記載のダブルパターン形成方法。
- 上記第1レジストパターン及び第2レジストパターンが、それぞれラインアンドスペースパターンであり、
上記第1レジストパターンのライン部と第2レジストパターンのライン部とを交互に配置する請求項1から請求項9のいずれか1項に記載のダブルパターン形成方法。 - 上記第1レジストパターン及び第2レジストパターンが、それぞれラインアンドスペースパターンであり、
上記第1レジストパターンのライン部と第2レジストパターンのライン部とを直交して配置する請求項1から請求項9のいずれか1項に記載のダブルパターン形成方法。
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