Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
  • C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
  • C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D307/56—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D307/58—One oxygen atom, e.g. butenolide
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D317/00—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms
  • C07D317/08—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3
  • C07D317/44—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 ortho- or peri-condensed with carbocyclic rings or ring systems
  • C07D317/70—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 ortho- or peri-condensed with carbocyclic rings or ring systems condensed with ring systems containing two or more relevant rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F12/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F12/02—Monomers containing only one unsaturated aliphatic radical
  • C08F12/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F12/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by hetero atoms or groups containing heteroatoms
• • 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
• • 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
• • 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
• • 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
• • 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
  • G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
  • G03F7/2004—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image characterised by the use of a particular light source, e.g. fluorescent lamps or deep UV light

Definitions

• the present invention relates to a radiation-sensitive resin composition and a pattern formation method.
• Photolithography technology uses a resist composition to form fine circuits in semiconductor elements.
• a coating of the resist composition is exposed to radiation through a mask pattern to generate an acid, which is then catalyzed by a reaction that creates a difference in the solubility of the resin in alkaline or organic solvent-based developers between exposed and unexposed areas, forming a resist pattern on a substrate.
• the present invention comprises: a radiation-sensitive onium salt containing a fluorine atom in the cation moiety; A compound represented by the following formula (H): A resin including a structural unit having an acid dissociable group; The present invention relates to a radiation-sensitive resin composition comprising: (In the above formula (H), R 1 to R 3 are each independently a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 20 carbon atoms.
• the radiation-sensitive resin composition has good storage stability and can form a resist film that satisfies sensitivity and LWR performance. Although the reason for this is unclear, it is presumed to be as follows. Due to the fluorine-containing onium cation portion of the onium salt, the absorption of radiation such as EUV with a wavelength of 13.5 nm by fluorine atoms is very large, and the secondary electron generation efficiency is also high, resulting in high sensitivity of the radiation-sensitive resin composition.
• the present invention provides a method for producing a pharmaceutical composition comprising the steps of: a step of directly or indirectly applying the radiation-sensitive resin composition onto a substrate to form a resist film; exposing the resist film to light; and developing the exposed resist film with a developer.
• the radiation-sensitive resin composition according to the present embodiment contains a compound represented by the following formula (H) and a resin. As long as the effect is not impaired, other optional components may be contained.
• the radiation-sensitive resin composition can exhibit good storage stability and the obtained resist film can have good properties. It is possible to provide high levels of sensitivity and LWR performance.
• the onium salt is a component that contains an organic acid anion moiety and an onium cation moiety and generates an acid upon exposure to light.
• the onium cation moieties in the onium salt is a fluorine-containing onium cation moiety that contains a fluorine atom, high sensitivity can be achieved by improving the radiation absorption efficiency (and secondary electron generation efficiency) and subsequently the acid generation efficiency.
• the onium salt may be contained in the radiation-sensitive resin composition in any form, but it is preferable that the onium salt is at least one selected from the group consisting of a radiation-sensitive acid generator containing the organic acid anion portion, and an acid diffusion controller that contains the organic acid anion portion and the onium cation portion and generates an acid having a higher pKa than the acid generated from the radiation-sensitive acid generator upon irradiation with radiation.
• the onium salt is at least one selected from the group consisting of a radiation-sensitive acid generator containing the organic acid anion portion, and an acid diffusion controller that contains the organic acid anion portion and the onium cation portion and generates an acid having a higher pKa than the acid generated from the radiation-sensitive acid generator upon irradiation with radiation.
• the acid generated by exposure of the onium salt is considered to have two functions in the radiation-sensitive resin composition depending on the strength of the acid.
• the first function is that, when the resin contains a structural unit having an acid-dissociable group, the acid generated by exposure dissociates the acid-dissociable group of the structural unit and generates a carboxyl group or the like.
• An onium salt having this first function is called a radiation-sensitive acid generator.
• the second function is that, under the pattern formation conditions using the radiation-sensitive resin composition, the acid-dissociable group of the resin is not substantially dissociated, and the diffusion of the acid generated from the radiation-sensitive acid generator in the unexposed area is suppressed by salt exchange.
• An onium salt having this second function is called an acid diffusion controller.
• the acid generated from the radiation-sensitive acid generator is a relatively stronger acid (an acid with a lower pKa) than the acid generated from the acid diffusion controller.
• an onium salt functions as a radiation-sensitive acid generator or an acid diffusion controller depends on the energy required for the acid-dissociable group in the resin to dissociate, the acidity of the onium salt, and other factors.
• the form in which the radiation-sensitive acid generator is contained in the radiation-sensitive resin composition is preferably a form in which the onium salt structure exists alone as a (low molecular weight) compound.
• the radiation-sensitive resin composition contains the radiation-sensitive acid generator, the polarity of the resin in the exposed areas increases, and the resin in the exposed areas becomes soluble in the developer when developed with an alkaline aqueous solution, but is poorly soluble in the developer when developed with an organic solvent.
• the acid diffusion control agent in the radiation-sensitive resin composition, it is possible to suppress the diffusion of acid in unexposed areas, and it is possible to form a resist pattern with superior pattern developability and LWR performance.
• the onium cation moiety in the radiation-sensitive acid generator is a fluorine-containing onium cation moiety.
• both the onium cation moiety in the acid diffusion controller and the onium cation moiety in the radiation-sensitive acid generator are the fluorine-containing onium cation moiety.
• the fluorine-containing onium cation moiety contains an aromatic ring structure having a fluorine atom (hereinafter also referred to as a "fluorine-substituted aromatic ring structure").
• fluorine-substituted aromatic ring structure By combining an electron-withdrawing fluorine atom with an aromatic ring structure, further improvement in radiation absorption efficiency can be expected.
• aromatic ring structure having a fluorine atom includes not only a structure in which a fluorine atom is directly bonded to an aromatic ring structure, but also a structure in which a fluorine atom is bonded to an aromatic ring structure via another atom (for example, a structure in which a fluorine atom is bonded to a substituent bonded to an aromatic ring structure, etc.).
• the radiation-sensitive resin composition contains a radiation-sensitive acid generator that generates an acid having a lower pKa than the acid generated from the acid diffusion controller upon irradiation (exposure) with radiation.
• the radiation-sensitive resin composition contains the radiation-sensitive acid generator, the acid generated upon exposure dissociates an acid-dissociable group in the resin to generate a carboxyl group or the like.
• the polarity of the resin in the exposed area increases, and the resin in the exposed area becomes soluble in a developer in the case of development with an aqueous alkali solution, whereas it becomes poorly soluble in a developer in the case of development with an organic solvent.
• the radiation-sensitive acid generator is preferably a radiation-sensitive onium salt containing an organic acid anion portion and an onium cation portion.
• the organic acid anion portion preferably contains at least one anion selected from the group consisting of sulfonate anion and sulfonimide anion. Acids generated by exposure include sulfonic acid and sulfonimide, which correspond to the organic acid anion portion.
• the organic acid anion portion preferably contains an iodine-substituted aromatic ring structure.
• the onium cation moiety in the radiation-sensitive acid generator can be a fluorine-containing onium cation moiety.
• a compound having one or more fluorine atoms or fluorinated hydrocarbon groups bonded to a carbon atom adjacent to a sulfonate anion can be suitably used as a radiation-sensitive acid generator that generates sulfonic acid upon exposure to light.
• the radiation-sensitive onium salt used as the radiation-sensitive acid generator is preferably represented by the following formula (1).
• R c1 to R c3 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, and at least one of R c1 to R c3 contains a fluorine atom or a trifluoromethyl group.
• the linear or branched alkyl group having 1 to 12 carbon atoms represented by R c1 to R c3 is preferably an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group having 3 to 12 carbon atoms, and some or all of the hydrogen atoms in these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, an amide group, a nitro group, a sultone group, a sulfone group or a sulfonium salt-containing group, and some of the methylene groups constituting these groups may be substituted with an ether group, an ester group, a carbonyl group, a carbonate group or a sulfonate ester group.
• the substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms represented by R c1 to R c3 is preferably an aryl group having 6 to 12 carbon atoms, and some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, an amide group, a nitro group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the methylene groups constituting these groups may be substituted with an ether group, an ester group, a carbonyl group, a carbonate group, or a sulfonate ester group.
• R c1 to R c3 is a phenyl group containing a fluorine atom or a trifluoromethyl group at the para position, a phenyl group containing a fluorine atom or a trifluoromethyl group at the meta position, or a phenyl group containing an iodine atom at the para position.
• Y c - is a monovalent anion.
• the monovalent anion represented by Y c — is not particularly limited, and examples thereof include an anion represented by R c ⁇ —SO 3 — .
• R c ⁇ is a monovalent organic group.
• the monovalent organic group represented by R c ⁇ may be a group obtained by removing one hydrogen atom from a monovalent organic group having 1 to 40 carbon atoms.
• the monovalent organic group having 1 to 40 carbon atoms may be a group containing any of a chain structure, a cyclic structure, or a combination thereof.
• the chain structure may be a chain hydrocarbon group, which may be saturated or unsaturated, linear or branched.
• the cyclic structure may be a cyclic hydrocarbon group, which may be alicyclic, aromatic or heterocyclic.
• the monovalent organic group is preferably a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, or a combination thereof.
• the monovalent organic group is preferably a group containing a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.
• the radiation-sensitive onium salt preferably contains an iodine atom. More specifically, the monovalent organic group represented by R c ⁇ is preferably a monovalent organic group having 1 to 40 carbon atoms containing 1 to 6 iodine atoms, and more preferably a monovalent organic group having 6 to 40 carbon atoms containing a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms substituted with 1 to 3 iodine atoms.
• the radiation-sensitive onium salt also preferably contains a partial structure having an acid-dissociable group. Examples of the partial structure having an acid-dissociable group include a group in which a hydrogen atom of a carboxy group is substituted with a group that dissociates under the action of an acid. Examples of the group that dissociates under the action of an acid include the same as the acid-dissociable group contained in the base resin described below.
• the onium cation portion of the radiation-sensitive acid generator represented by formula (1) includes, but is not limited to, the following:
• the organic acid anion portion of the radiation-sensitive acid generator represented by formula (1) includes, but is not limited to, those shown below. Note that, as the organic acid anion portion that does not have an iodine-substituted aromatic ring structure, a structure in which the iodine atom in the following formula is replaced with an atom or group other than an iodine atom, such as a hydrogen atom or other substituent, can be preferably used.
• Examples of the radiation-sensitive onium salt represented by formula (1) include, but are not limited to, the compounds represented by (B-1) to (B-11) below.
• the lower limit of the content of the radiation-sensitive acid generator is preferably 1 part by mass, more preferably 3 parts by mass, even more preferably 5 parts by mass, and particularly preferably 8 parts by mass, relative to 100 parts by mass of the resin.
• the upper limit of the content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less, relative to 100 parts by mass of the resin. This allows excellent sensitivity and CDU performance to be exhibited when forming a resist pattern.
• the acid diffusion controller contains an organic acid anion moiety and an onium cation moiety, and generates an acid having a higher pKa than the acid generated from the radiation-sensitive acid generator upon irradiation with radiation.
• An example of such an organic acid anion moiety is carboxylic acid.
• the organic acid anion moiety preferably contains an iodine-substituted aromatic ring structure.
• the acid diffusion controller is preferably represented by the following formula (S-1) or (S-2):
• R 1 is a hydrogen atom, a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a carboxy group, or a cyano group, or an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, or an alkylsulfonyloxy group having 1 to 4 carbon atoms, which may be substituted with a halogen atom, or -NR 1A -C( ⁇ O)-R 1B or -NR 1A -C( ⁇ O)-O-R 1B .
• R 1A is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms
• R 1B is an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 8 carbon atoms.
• the alkyl group having 1 to 6 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a cyclobutyl group, an n-pentyl group, a cyclopentyl group, an n-hexyl group, and a cyclohexyl group.
• Examples of the alkyl moiety of the alkoxy group having 1 to 6 carbon atoms, the acyloxy group having 2 to 7 carbon atoms, and the alkoxycarbonyl group having 2 to 7 carbon atoms include the same as the specific examples of the alkyl group described above, and examples of the alkyl moiety of the alkylsulfonyloxy group having 1 to 4 carbon atoms include those having 1 to 4 carbon atoms among the specific examples of the alkyl group described above.
• the alkenyl group having 2 to 8 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include a vinyl group, a 1-propenyl group, and a 2-propenyl group.
• R 1 include a fluorine atom, a chlorine atom, a hydroxyl group, an amino group, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, -NR 1A -C( ⁇ O)-R 1B , -NR 1A -C( ⁇ O)-O-R 1B , and the like.
• R 3 , R 4 , R 5 , R 6 and R 7 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom.
• the onium cation portion of the acid diffusion controller has a fluorine atom
• at least one of R 3 , R 4 and R 5 contains one or more fluorine atoms
• at least one of R 6 and R 7 contains one or more fluorine atoms.
• Any two of R 3 , R 4 and R 5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
• the monovalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms.
• some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, an amide group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, a carbonate group, or a sulfonate ester bond.
• At least one of R 3 , R 4, and R 5 is a phenyl group containing a fluorine atom or a trifluoromethyl group at the para position, a phenyl group containing a fluorine atom or a trifluoromethyl group at the meta position, or a phenyl group containing an iodine atom at the para position.
• R 6 and R 7 is a phenyl group containing a fluorine atom or a trifluoromethyl group at the para position, a phenyl group containing a fluorine atom or a trifluoromethyl group at the meta position, or a phenyl group containing an iodine atom at the para position.
• L1 is a single bond or a divalent linking group having 1 to 20 carbon atoms, which may contain an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, or a carboxy group.
• n and n are integers satisfying 0 ⁇ m ⁇ 5, 0 ⁇ n ⁇ 3, and 0 ⁇ m+n ⁇ 5, but are preferably integers satisfying 1 ⁇ m ⁇ 3 and 0 ⁇ n ⁇ 3, or 0 ⁇ m ⁇ 3 and 1 ⁇ n ⁇ 3.
• R 1 is preferably a hydroxy group.
• n is 2 or more, at least one R 1 is preferably a hydroxy group, a fluorine atom, or a fluorinated hydrocarbon group.
• n it is preferable that both R 1s are hydroxy groups, or that one R 1 is a hydroxy group and the remaining R 1 is a fluorine atom or a fluorinated hydrocarbon group.
• the organic acid anion portion of the acid diffusion control agent represented by the above formula (S-1) or (S-2) includes, but is not limited to, those shown below. Note that all of the organic acid anion portions shown below have an iodine-substituted aromatic ring structure, but as an organic acid anion portion that does not have an iodine-substituted aromatic ring structure, a structure in which the iodine atom in the below formula is replaced with an atom or group other than an iodine atom, such as a hydrogen atom or other substituent, can be suitably used.
• the onium cation moiety in the acid diffusion controller represented by the above formulae (S-1) and (S-2) is preferably an onium cation containing an aromatic ring structure having a fluorine atom, more preferably an onium cation containing an aromatic ring structure having a fluorine atom or a CF3 group.
• Specific examples include the onium cation in the radiation-sensitive onium salt represented by the above formula (1).
• the acid diffusion control agents represented by the above formulas (S-1) and (S-2) can also be synthesized by known methods, in particular by salt exchange reactions. Known acid diffusion control agents can also be used as long as they do not impair the effects of the present invention.
• the content of the acid diffusion control agent relative to the content of the radiation-sensitive acid generator is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more.
• the above content is preferably 100% by mass or less, more preferably 80% by mass or less, and even more preferably 60% by mass or less. This allows excellent sensitivity and LWR performance to be exhibited when forming a resist pattern.
• the content of the acid diffusion control agent is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, based on the radiation-sensitive acid generator (if multiple acid generators are included, the total amount of the radiation-sensitive acid generators).
• the content is preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less. This allows the storage stability to be exhibited.
• R 1 to R 3 are each independently a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 20 carbon atoms.
• the aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R 1 to R 3 may be any of linear, branched, and cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an alkynyl group having 2 to 20 carbon atoms.
• the above-mentioned linear structure may be a linear hydrocarbon group, whether saturated or unsaturated, linear or branched.
• the above-mentioned cyclic structure may be an alicyclic cyclic hydrocarbon group.
• R 2 and R 3 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
• some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, an amide group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, a carbonate group, or a sulfonate ester bond.
• the alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, and cyclohexyl.
• the alkenyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include vinyl, 1-propenyl, and 2-propenyl.
• the alkynyl group having 2 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include ethynyl and propargyl.
• Compound (H) may be any known or novel compound.
• Examples of the compound (H) include methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, isopropyl 2-hydroxyisobutyrate, and methyl 2-hydroxy 2-methylbutyrate. These may be used alone or in combination of two or more.
• the compound (H) may be used alone or in combination of two or more kinds.
• the content of the compound (H) (when a plurality of compounds (H) are contained, the total of the compounds) is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, particularly preferably 55% by mass or more, and even more preferably 60% by mass or more, based on the radiation-sensitive resin composition.
• the content is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, and particularly preferably 75% by mass or less. This allows the storage stability performance to be exhibited.
• the content of the compound (H) is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 45% by mass or more, particularly preferably 55% by mass or more, and even more preferably 65% by mass or more, based on the total of the compound (H) and the solvent. This allows the composition to exhibit storage stability.
• the content may be 100% by mass (i.e., it may not contain the solvent described later), or may be 95% by mass or less.
• the resin is an assembly of polymers containing a structural unit having an acid-dissociable group (hereinafter, also referred to as "structural unit (I)").
• structural unit (I) the base resin may contain a structural unit (II) having a phenolic hydroxyl group, a structural unit (III) containing a heteroatom-containing substituent, a structural unit (IV) containing a lactone structure, etc.
• structural unit will be described below.
• the structural unit (I) is a structural unit having an acid dissociable group.
• the term "acid dissociable group” refers to a group that substitutes a hydrogen atom of an alkali-soluble group such as a carboxyl group, a phenolic hydroxyl group, a sulfo group, or a sulfonamide group, and dissociates under the action of an acid. Therefore, the acid dissociable group is bonded to the oxygen atom that was bonded to the hydrogen atom in these functional groups.
• the structural unit (I) is not particularly limited as long as it has an acid-dissociable group, and examples thereof include a structural unit having a tertiary alkyl ester moiety, a structural unit having a structure in which the hydrogen atom of a phenolic hydroxyl group is replaced with a tertiary alkyl group, a structural unit having an acetal bond, and the like.
• the structural unit represented by the following formula (3) hereinafter also referred to as "structural unit (1-1)
• structural unit (1-1) is preferred.
• R 7 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.
• R 8 is a hydrogen atom, or a monovalent hydrocarbon group having 1 to 20 carbon atoms.
• R 9 and R 10 each independently represent a monovalent linear hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a divalent alicyclic group having 3 to 20 carbon atoms constituted by combining these groups together with the carbon atom to which they are bonded.
• Ar is a single bond or a substituted or unsubstituted phenylene group.
• L 1 represents a single bond or a divalent linking group.
• R 7 is preferably a hydrogen atom or a methyl group, and more preferably a methyl group.
• Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R8 include a chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.
• Examples of the chain hydrocarbon group having 1 to 10 carbon atoms represented by R 8 to R 10 include linear or branched saturated hydrocarbon groups having 1 to 10 carbon atoms, and linear or branched unsaturated hydrocarbon groups having 1 to 10 carbon atoms.
• Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R 8 to R 10 include monocyclic or polycyclic saturated hydrocarbon groups, and monocyclic or polycyclic unsaturated hydrocarbon groups.
• Preferred examples of the monocyclic saturated hydrocarbon group include cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups.
• Preferred examples of the polycyclic cycloalkyl group include bridged alicyclic hydrocarbon groups such as norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl groups.
• the bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two carbon atoms that are not adjacent to each other among the carbon atoms constituting the alicyclic ring are linked by a linking group containing one or more carbon atoms.
• Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R8 include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group; and aralkyl groups such as a benzyl group, a phenethyl group, and a naphthylmethyl group.
• R 8 is preferably a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms.
• the divalent alicyclic group having 3 to 20 carbon atoms constituted by combining R9 and R10 together with the carbon atom to which they are bonded is not particularly limited as long as it is a group in which two hydrogen atoms have been removed from the same carbon atom constituting a carbon ring of a monocyclic or polycyclic alicyclic hydrocarbon having the above carbon number. It may be either a monocyclic hydrocarbon group or a polycyclic hydrocarbon group, and the polycyclic hydrocarbon group may be either a bridged alicyclic hydrocarbon group or a condensed alicyclic hydrocarbon group, and may be either a saturated hydrocarbon group or an unsaturated hydrocarbon group.
• the condensed alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group constituted in such a way that a plurality of alicyclic rings share a side (a bond between two adjacent carbon atoms).
• preferred saturated hydrocarbon groups include cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, and cyclooctanediyl groups
• preferred unsaturated hydrocarbon groups include cyclopentenediyl, cyclohexenediyl, cycloheptenediyl, cyclooctenediyl, and cyclodecenediyl groups.
• Preferred polycyclic alicyclic hydrocarbon groups include bridged alicyclic saturated hydrocarbon groups, such as bicyclo[2.2.1]heptane-2,2-diyl (norbornane-2,2-diyl), bicyclo[2.2.2]octane-2,2-diyl, and tricyclo[3.3.1.1 3,7 ]decane-2,2-diyl (adamantane-2,2-diyl).
• the phenylene group represented by Ar may be a 1,4-phenylene group, a 1,3-phenylene group, or a 1,2-phenylene group.
• Examples of the divalent linking group represented by L1 include an alkanediyl group, a cycloalkanediyl group, an alkenediyl group, * -R LA O-, and * -R LB COO- (where * represents a bond to an oxygen atom).
• the carbon atom bonded to the oxygen atom of -COO- in formula (3) is a tertiary carbon and does not have a hydrogen atom.
• Some or all of the hydrogen atoms on the carbon atoms in R 8 to R 10 and L 1 may be substituted with a halogen atom such as a fluorine atom, a chlorine atom or an iodine atom, a halogenated alkyl group such as a trifluoromethyl group, an alkoxy group such as a methoxy group, a cyano group, etc.
• a halogen atom such as a fluorine atom, a chlorine atom or an iodine atom
• a halogenated alkyl group such as a trifluoromethyl group
• an alkoxy group such as a methoxy group, a cyano group, etc.
• alkanediyl group examples include methanediyl, 1,1-ethanediyl, 1,2-ethanediyl, 1,1-propanediyl, 1,2-propanediyl, 1,3-propanediyl, 1,4-butanediyl, 1,5-pentanediyl, 1,6-hexanediyl, 1,7-heptanediyl, 1,8-octanediyl, 1,9-nonanediyl, and 1,10-decanediyl groups.
• the alkanediyl group is preferably an alkanediyl group having 1 to 8 carbon atoms.
• cycloalkanediyl group examples include monocyclic cycloalkanediyl groups such as cyclopentanediyl and cyclohexanediyl groups; and polycyclic cycloalkanediyl groups such as norbornanediyl and adamantanediyl groups.
• the cycloalkanediyl group is preferably a cycloalkanediyl group having 5 to 12 carbon atoms.
• alkenediyl group examples include ethenediyl, propenediyl, and butenediyl groups.
• the alkenediyl group is preferably an alkenediyl group having 2 to 6 carbon atoms.
• R LA in the above * -R LA O- examples include the above alkanediyl group, cycloalkanediyl group, alkenediyl group, etc.
• R LB in the above * -R LB COO- examples include the above alkanediyl group, cycloalkanediyl group, alkenediyl group, arenediyl group, etc.
• arenediyl groups include phenylene group, tolylene group, naphthylene group, etc. As the arenediyl group, an arenediyl group having 6 to 15 carbon atoms is preferable.
• R8 is an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, and that the alicyclic structure formed by combining R9 and R10 together with the carbon atoms to which they are bonded is a polycyclic or monocyclic cycloalkane structure. It is preferred that L1 is a single bond or * -RLAO- . RLA is preferably an alkanediyl group.
• structural unit (1-1) examples include structural units represented by the following formulas (3-1) to (3-8) (hereinafter also referred to as "structural units (1-1-1) to (1-1-8)").
• R 7 to R 10 , R LA , and Ar are the same as those in the above formula (3).
• R LM and R LN are each independently a monovalent hydrocarbon group having 1 to 10 carbon atoms.
• i and j are each independently an integer of 1 to 4.
• n A , n B , and n C are each independently 0 or 1.
• R LM and R LN include groups corresponding to the carbon number of 1 to 10 among the monovalent hydrocarbon groups having 1 to 20 carbon atoms represented by R 8 in the above formula (3).
• R LM and R LN are preferably a methyl group, an ethyl group, or an isopropyl group.
• R 8 to R 10 are preferably a methyl group, an ethyl group, an isopropyl group, a phenyl group or an iodophenyl group.
• the base resin may contain one or a combination of two or more types of structural unit (I).
• the resin may further contain, as structural unit (I), structural units represented by the following formulae (1f) to (2f) in addition to or in place of the structural unit (1-1):
• R ⁇ f is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.
• R ⁇ f is independently a hydrogen atom or a chain alkyl group having 1 to 5 carbon atoms.
• Ar has the same meaning as in the above formula (3).
• h 1 is independently an integer of 1 to 4.
• R ⁇ f is preferably a hydrogen atom, a methyl group or an ethyl group.
• the lower limit of the content of the structural unit (I) is preferably 20 mol%, more preferably 30 mol%, even more preferably 40 mol%, and particularly preferably 50 mol%, based on all structural units constituting the base resin.
• the upper limit of the above content is preferably 90 mol%, more preferably 80 mol%, even more preferably 70 mol%, and particularly preferably 65 mol%.
• the structural unit (II) is a structural unit having a phenolic hydroxyl group (excluding the case of the structural unit (I)).
• the phenolic hydroxyl group generated by deprotection under the action of the acid generated by exposure is also included as the phenolic hydroxyl group of the structural unit (II).
• the structural unit (II) contributes to improving the etching resistance and improving the difference in developer solubility (dissolution contrast) between the exposed portion and the unexposed portion.
• it can be suitably applied to pattern formation using exposure to radiation having a wavelength of 50 nm or less, such as electron beam or EUV.
• the structural unit (II) is preferably represented by the following formula (2).
• R ⁇ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
• L CA is a single bond, —COO— * or —O—. * is a bond on the aromatic ring side.
• R 101 is a hydrogen atom or a protecting group which is deprotected by the action of an acid. When a plurality of R 101 are present, the plurality of R 101 are the same or different from each other.
• R 102 is a cyano group, a nitro group, an alkyl group, a fluorinated alkyl group, an alkoxycarbonyloxy group, an acyl group or an acyloxy group.
• n3 is an integer from 0 to 2
• m3 is an integer from 1 to 8
• m4 is an integer from 0 to 8, provided that 1 ⁇ m3 + m4 ⁇ 2n3 +5 is satisfied.
• R ⁇ is preferably a hydrogen atom or a methyl group.
• L CA is preferably a single bond or --COO-- * .
• Examples of the protecting group which can be removed by the action of an acid and is represented by R 101 above include groups represented by the following formulae (AL-1) to (AL-3).
• R M1 and R M2 are monovalent hydrocarbon groups, which may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms.
• the monovalent hydrocarbon groups may be linear, branched, or cyclic, and are preferably alkyl groups having 1 to 40 carbon atoms, and more preferably alkyl groups having 1 to 20 carbon atoms.
• a is an integer of 0 to 10, and preferably an integer of 1 to 5.
• * represents a bond to another moiety.
• R M3 and R M4 are each independently a hydrogen atom or a monovalent hydrocarbon group, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a fluorine atom.
• the monovalent hydrocarbon group may be linear, branched or cyclic, and is preferably an alkyl group having 1 to 20 carbon atoms. Any two of R M2 , R M3 and R M4 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded, or a carbon atom and an oxygen atom.
• a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.
• R M5 , R M6 and R M7 are each independently a monovalent hydrocarbon group, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a fluorine atom.
• the above monovalent hydrocarbon group may be linear, branched or cyclic, and is preferably an alkyl group having 1 to 20 carbon atoms.
• any two of R M5 , R M6 and R M7 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
• a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.
• the group represented by the above formula (AL-3) is preferred as a protecting group that is deprotected by the action of an acid.
• Examples of the alkyl group in R 102 include linear or branched alkyl groups having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, and a propyl group.
• Examples of the fluorinated alkyl group include linear or branched fluorinated alkyl groups having 1 to 8 carbon atoms, such as a trifluoromethyl group and a pentafluoroethyl group.
• Examples of the alkoxycarbonyloxy group include linear or alicyclic alkoxycarbonyloxy groups having 2 to 16 carbon atoms, such as a methoxycarbonyloxy group, a butoxycarbonyloxy group, and an adamantylmethyloxycarbonyloxy group.
• acyl group examples include aliphatic or aromatic acyl groups having 2 to 12 carbon atoms, such as an acetyl group, a propionyl group, a benzoyl group, and an acryloyl group.
• acyloxy group examples include aliphatic or aromatic acyloxy groups having 2 to 12 carbon atoms, such as an acetyloxy group, a propionyloxy group, a benzoyloxy group, and an acryloyloxy group.
• m3 is preferably an integer of 1 to 3, and more preferably 1 or 2.
• the structural unit (II) is preferably one of the structural units represented by the following formulas (2-1) to (2-11) (hereinafter also referred to as “structural unit (2-1) to structural unit (2-11)").
• R ⁇ is the same as in the above formula (2).
• the structural units (2-1) to (2-4), (2-6), (2-8), (2-9) and (2-11) are preferred.
• the lower limit of the content of the structural unit (II) (total when multiple types of structural unit (II) are present) is preferably 10 mol%, more preferably 15 mol%, even more preferably 20 mol%, and particularly preferably 25 mol%, based on all structural units constituting the base resin.
• the upper limit of the above content is preferably 60 mol%, more preferably 55 mol%, even more preferably 50 mol%, and particularly preferably 45 mol%.
• the structural unit (III) is a structural unit (excluding structures corresponding to the structural units (I) to (II)) having a heteroatom-containing substituent such as a fluorine atom, an alcoholic hydroxyl group, a carboxy group, a cyano group, a nitro group, or a sulfonamide group.
• a structural unit having a fluorine atom, a structural unit having an alcoholic hydroxyl group, and a structural unit having a carboxy group are preferred, and a structural unit having a fluorine atom and a structural unit having an alcoholic hydroxyl group are more preferred.
• structural unit (III) examples include structural units represented by the following formula:
• R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
• the lower limit of the content of the structural unit (III) is preferably 3 mol%, more preferably 5 mol%, and even more preferably 8 mol%, based on all structural units constituting the base resin.
• the upper limit of the above content is preferably 20 mol%, more preferably 15 mol%, and even more preferably 12 mol%.
• the structural unit (IV) is a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure.
• the base resin further contains the structural unit (IV), which allows the base resin to adjust its solubility in a developer, and as a result, the radiation-sensitive resin composition can improve lithography performance such as resolution. In addition, the adhesion between a resist pattern formed from the base resin and a substrate can be improved.
• the base resin can be synthesized, for example, by polymerizing monomers that provide each structural unit in an appropriate solvent using a known radical polymerization initiator or the like.
• the molecular weight of the resin serving as the base resin is not particularly limited, but the lower limit of the weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 1,000, more preferably 2,000, even more preferably 3,000, and particularly preferably 4,000.
• the upper limit of the Mw is preferably 30,000, more preferably 20,000, even more preferably 10,000, and particularly preferably 8,000. If the Mw of the resin is within the above range, the heat resistance and developability of the resulting resist film are good.
• the ratio of Mw to the polystyrene equivalent number average molecular weight (Mn) of the base resin by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, and more preferably 1 or more and 2 or less.
• the resin content is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, based on the total solid content of the radiation-sensitive resin composition.
• the resin may further contain a structural unit having an organic acid anion portion and an onium cation portion as a structural unit (V).
• the resin may function as an acid generator by containing the structural unit (V).
• the composition may or may not contain a radiation-sensitive acid generator.
• the structural unit (V) is preferably represented by the following formula (a1) or (a2).
• R A is a hydrogen atom or a methyl group.
• X 1 is a single bond or an ester group.
• X 2 is a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, or an arylene group having 6 to 10 carbon atoms, a part of the methylene groups constituting the alkylene group may be substituted with an ether group, an ester group or a lactone ring-containing group, and at least one hydrogen atom contained in X 2 may be substituted with an iodine atom.
• X 3 is a single bond, an ether group, an ester group, or a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, a part of the methylene groups constituting the alkylene group may be substituted with an ether group or an ester group.
• Rf 1 to Rf 4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one is a fluorine atom or a fluorinated hydrocarbon group.
• R 43 to R 47 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, and R 43 and R 44 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
• the monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom in R 43 to R 47 is preferably an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, or an aryl group having 6 to 20 carbon atoms, some or all of the hydrogen atoms in these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, an amide group, a nitro group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the methylene groups constituting these groups may be substituted with an ether group, an ester group, a carbonyl group, a carbonate group, or a sulfonate ester group.
• R A , R 43 to R 47 , Rf 1 to Rf 4 and X 1 are defined as in formula (a1) or (a2).
• R 48 is a linear, branched or cyclic alkyl group having 1 to 4 carbon atoms, a halogen atom other than an iodine atom, a hydroxy group, a linear, branched or cyclic alkoxy group having 1 to 4 carbon atoms, or a linear, branched or cyclic alkoxycarbonyl group having 2 to 5 carbon atoms.
• m is an integer of 0 to 4.
• n is an integer of 0 to 3.
• the organic acid anion portion of the monomer that gives the structural unit (V) includes, but is not limited to, those shown below. Note that all of the organic acid anion portions shown below have an iodine-substituted aromatic ring structure, but as an organic acid anion portion that does not have an iodine-substituted aromatic ring structure, a structure in which the iodine atom in the following formula is replaced with an atom or group other than an iodine atom, such as a hydrogen atom or other substituent, can be preferably used.
• the onium cation moiety in the structural unit (V) can suitably be the onium cation moiety of the radiation-sensitive acid generator and the acid diffusion controller.
• the lower limit of the content of structural unit (V) (the total content when multiple types are contained) is preferably 5 mol %, more preferably 10 mol %, and even more preferably 12 mol %, of all structural units constituting the base resin.
• the upper limit of the above content is preferably 30 mol %, more preferably 25 mol %, and even more preferably 20 mol %.
• the monomer that gives the structural unit (V) can be synthesized, for example, in a manner similar to that of the sulfonium salt having a polymerizable anion described in Japanese Patent No. 5201363.
• the radiation-sensitive resin composition of the present embodiment may contain, as another resin, a resin having a higher mass content of fluorine atoms than the base resin (hereinafter, also referred to as a "high-fluorine content resin").
• a resin having a higher mass content of fluorine atoms than the base resin hereinafter, also referred to as a "high-fluorine content resin”
• the high-fluorine content resin can be unevenly distributed in the surface layer of the resist film relative to the base resin, and as a result, the state of the resist film surface and the component distribution in the resist film can be controlled to a desired state.
• the high fluorine content resin can be synthesized by the same method as the above-mentioned method for synthesizing the base resin.
• the radiation-sensitive resin composition according to the present embodiment may further contain a solvent, as desired.
• the solvent is not particularly limited as long as it is capable of dissolving or dispersing at least the onium salt, the base resin, and the compound represented by formula (H) above, and additives and the like that are optionally contained therein.
• solvents examples include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents.
• Alcohol-based solvents include: Monoalcohol solvents having 1 to 18 carbon atoms, such as isopropanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol; Polyhydric alcohol solvents having 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; Examples of the polyhydric alcohol partially etherified solvents include those obtained by etherifying some of the hydroxy groups of the above-mentioned polyhydric alcohol solvents.
• ether solvents include: Dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; Aromatic ring-containing ether solvents such as diphenyl ether and anisole (methyl phenyl ether);
• polyhydric alcohol solvent include polyhydric alcohol ether solvents obtained by etherifying the hydroxyl groups of the above-mentioned polyhydric alcohol solvents.
• ketone solvent examples include chain ketone solvents such as acetone, butanone, and methyl-iso-butyl ketone: Cyclic ketone solvents such as cyclopentanone, cyclohexanone, methylcyclohexanone, etc.: Examples include 2,4-pentanedione, acetonylacetone, and acetophenone.
• amide solvent examples include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone;
• solvent examples include chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.
• ester-based solvents include: Monocarboxylate ester solvents such as n-butyl acetate and ethyl lactate; polyhydric alcohol partial ether acetate solvents, such as diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; Lactone solvents such as ⁇ -butyrolactone and valerolactone; Carbonate solvents such as diethyl carbonate, ethylene carbonate, and propylene carbonate; Examples of the solvent include polyvalent carboxylate diester solvents such as propylene glycol diacetate, methoxytriglycol acetate, diethyl oxalate, ethyl acetoacetate, ethyl lactate, and diethyl phthalate.
• Monocarboxylate ester solvents such as n-butyl acetate and ethyl lactate
• hydrocarbon solvent examples include aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane;
• solvent examples include aromatic hydrocarbon solvents such as benzene, toluene, di-iso-propylbenzene, and n-amylnaphthalene.
• the radiation-sensitive resin composition may contain one or more types of solvents.
• the radiation-sensitive resin composition may contain other optional components in addition to the above components.
• the other optional components include a crosslinking agent, a localization promoter, a surfactant, an alicyclic skeleton-containing compound, a sensitizer, etc. These other optional components may be used alone or in combination of two or more.
• the radiation-sensitive resin composition can be prepared, for example, by mixing an onium salt, a base resin, and the compound represented by formula (H) with other optional components as necessary in a predetermined ratio. After mixing, the radiation-sensitive resin composition is preferably filtered, for example, with a filter having a pore size of about 0.05 ⁇ m to 0.4 ⁇ m.
• the solid content concentration of the radiation-sensitive resin composition is usually 0.1% by mass to 50% by mass, preferably 0.5% by mass to 30% by mass, and more preferably 1% by mass to 20% by mass.
• the pattern forming method in this embodiment includes the steps of: A step (1) of directly or indirectly applying the radiation-sensitive resin composition to a substrate to form a resist film (hereinafter also referred to as a "resist film forming step”); A step (2) of exposing the resist film to light (hereinafter also referred to as an "exposure step”); and The method includes a step (3) of developing the exposed resist film (hereinafter, also referred to as the "developing step”).
• the above pattern formation method uses the above radiation-sensitive resin composition, which has excellent sensitivity and LWR performance in the exposure process, and therefore can form a high-quality resist pattern. Each step is described below.
• a resist film is formed from the radiation-sensitive resin composition.
• the substrate on which the resist film is formed include conventionally known substrates such as silicon wafers, silicon dioxide, and aluminum-coated wafers.
• an organic or inorganic anti-reflective film disclosed in, for example, JP-B-6-12452 or JP-A-59-93448 may be formed on the substrate.
• the coating method include spin coating, casting coating, and roll coating. After coating, pre-baking (PB) may be performed as necessary to volatilize the solvent in the coating film.
• the PB temperature is usually 60° C. to 150° C., and preferably 80° C. to 140° C.
• the PB time is usually 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds.
• the thickness of the resist film formed is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.
• the resist film formed in the resist film forming step (1) above is irradiated with radiation through a photomask (or, in some cases, through an immersion medium such as water) to expose the resist film.
• radiation used for exposure include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV (extreme ultraviolet light), X-rays, and gamma rays; charged particle beams such as electron beams and alpha rays, depending on the line width of the target pattern.
• far ultraviolet light, electron beams, and EUV are preferred
• ArF excimer laser light wavelength 193 nm
• KrF excimer laser light wavelength 248 nm
• electron beams, and EUV are more preferred
• PEB post-exposure bake
• This PEB creates a difference in solubility in the developer between the exposed and unexposed parts.
• the PEB temperature is usually 50°C to 180°C, with 80°C to 130°C being preferred.
• the PEB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred.
• step (3) above the resist film exposed in the exposure step (2) above is developed. This allows a desired resist pattern to be formed. After development, the resist film is generally washed with a rinse liquid such as water or alcohol, and then dried.
• a rinse liquid such as water or alcohol
• examples of the developer used in the above development include an alkaline aqueous solution in which at least one alkaline compound such as 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 (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene is dissolved.
• TMAH tetramethylammonium hydroxide
• TMAH tetramethylammonium hydroxide
• TMAH 1,8-diazabicyclo-[5.4.0]-7-undecene
• examples of the organic solvent include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, and alcohol solvents, or solvents containing organic solvents.
• examples of the organic solvent include one or more of the solvents listed as the solvents for the radiation-sensitive resin composition described above.
• ester solvents and ketone solvents are preferred.
• As the ester solvent acetate solvents are preferred, and n-butyl acetate and amyl acetate are more preferred.
• As the ketone solvent chain ketones are preferred, and 2-heptanone is more preferred.
• the cooled polymerization solution was poured into hexane (500 parts by mass relative to the polymerization solution), and the precipitated white powder was filtered off.
• the filtered white powder was washed twice with 100 parts by mass of hexane relative to the polymerization solution, and then dissolved in 1-methoxy-2-propanol (300 parts by mass).
• methanol 500 parts by mass
• triethylamine 50 parts by mass
• ultrapure water 10 parts by mass
• the cooled polymerization solution was poured into hexane (500 parts by mass relative to the polymerization solution), and the precipitated white powder was filtered off.
• the filtered white powder was washed twice with 100 parts by mass of hexane relative to the polymerization solution, and then dried at 50°C for 12 hours to obtain a white powdery polymer (A-11).
• a radiation-sensitive resin composition (R-1) was prepared by blending and mixing 100 parts by mass of [A] polymer (A-1), 20 parts by mass of [B] radiation-sensitive acid generator (B-1), 20 mol% of [C] acid diffusion controller (C-1) relative to (B-1), 2,000 parts by mass of [E] organic solvent (E-1), and 4,800 parts by mass of [D] organic solvent (D-1). The mixture was then filtered through a filter having a pore size of 0.20 ⁇ m.
• the resist film was subjected to PEB at 110°C for 60 seconds. Then, the resist was developed with a 2.38 wt % aqueous TMAH solution at 23° C. for 30 seconds to form a positive type 32 nm line and space pattern.
• the resist film was subjected to PEB at 110°C for 60 seconds. Then, the wafer was developed at 23°C for 30 seconds using a 2.38 wt% TMAH aqueous solution to form a positive 150 nm line and space pattern.
• the exposure amount required to form a 32 nm line and space pattern was determined as the optimum exposure amount, and this optimum exposure amount was determined as the sensitivity (mJ/ cm2 ).
• the sensitivity was judged as "A” (good) when it was 30 mJ/ cm2 or less, “B” (fairly good) when it was more than 30 mJ/ cm2 and 32 mJ/cm2 or less, and "C” (poor) when it exceeded 32 mJ/ cm2 .
• LWR performance The resist pattern formed by the above-mentioned method for forming a resist pattern by EUV exposure was observed from above using a scanning electron microscope. The line width was measured at 50 arbitrary points, and the 3 sigma value was calculated from the distribution of the measured values, which was defined as the LWR (unit: nm). The smaller the LWR value, the smaller the line wobble and the better the LWR performance. The LWR performance was evaluated as "A" (good) when the LWR was 4.0 nm or less, "B” (fairly good) when it was more than 4.0 nm and less than 4.2 nm, and "C” (bad) when it was more than 4.2 nm.
• the radiation-sensitive resin compositions of the Examples all had good sensitivity and LWR while ensuring storage stability compared to the radiation-sensitive resin compositions of the Comparative Examples.
• the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention can improve sensitivity and LWR while ensuring storage stability, and therefore can be suitably used for forming fine resist patterns in the lithography process of various electronic devices such as semiconductor devices and liquid crystal devices.

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