Classifications

• • 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
• • 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
  • C08F36/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
  • C08F36/02—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F36/20—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds unconjugated
• • 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
  • C08F12/16—Halogens
  • C08F12/20—Fluorine
• • 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
  • C08F12/22—Oxygen
• • 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
  • C08F12/22—Oxygen
  • C08F12/24—Phenols or alcohols
• • 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
  • C08F12/32—Monomers containing only one unsaturated aliphatic radical containing two or more 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
  • C08F212/00—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
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by heteroatoms or groups containing heteroatoms
  • C08F212/16—Halogens
  • C08F212/20—Fluorine
• • C—CHEMISTRY; METALLURGY
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  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—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
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by heteroatoms or groups containing heteroatoms
  • C08F212/22—Oxygen
• • C—CHEMISTRY; METALLURGY
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  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—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
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/14—Monomers containing only one unsaturated aliphatic radical containing one ring substituted by heteroatoms or groups containing heteroatoms
  • C08F212/22—Oxygen
  • C08F212/24—Phenols or alcohols
• • 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
  • C08F22/00—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 a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides or nitriles thereof
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D125/00—Coating compositions based on homopolymers or 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; Coating compositions based on derivatives of such polymers
  • C09D125/18—Homopolymers or copolymers of aromatic monomers containing elements other than carbon and hydrogen
• • 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
  • G03F7/0046—Photosensitive materials with perfluoro compounds, e.g. for dry lithography
• • 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
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
• • 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
  • C08F212/00—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
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/32—Monomers containing only one unsaturated aliphatic radical containing two or more rings
• • 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
  • G03F7/038—Macromolecular compounds which are rendered insoluble or differentially wettable
  • G03F7/0382—Macromolecular compounds which are rendered insoluble or differentially wettable the macromolecular compound being present in a chemically amplified negative photoresist composition
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/1053—Imaging affecting physical property or radiation sensitive material, or producing nonplanar or printing surface - process, composition, or product: radiation sensitive composition or product or process of making binder containing
  • Y10S430/1055—Radiation sensitive composition or product or process of making
  • Y10S430/106—Binder containing
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/1053—Imaging affecting physical property or radiation sensitive material, or producing nonplanar or printing surface - process, composition, or product: radiation sensitive composition or product or process of making binder containing
  • Y10S430/1055—Radiation sensitive composition or product or process of making
  • Y10S430/114—Initiator containing

Definitions

• the invention relates to photoresist polymers and photoresist compositions including the polymers.
• the invention relates to polymers and photoresist compositions suitable for photolithography processing wherein the polymers include repeating units based on derivatives of Meldrum's acid (i.e., 2,2-dimethyl-l,3-dioxane-4,6-dione).
• EUV lithography is the leading candidate for 32nm half-pitch device manufacturing. Even though the current lack of progress in tool and resist availability has cast doubt on this assertion, EUV is still considered as one of the candidates for this generation of lithography .
• One of the concerns of EUV resists is outgassing, which can contaminate the optics when the resist is irradiated with highly energetic EUV radiation under vacuum. It has been demonstrated that EUV outgassing is higher than outgassing at 193nm and 157nm for a particular resist (W. D. Domke et al, Proc. SPIE 5753, 1066, 2005).
• low activation energy (low Ea) protecting groups are preferred (G. M. Wallraff et al., J. Vac.
• polymers suitable for use in photoresist compositions for advanced lithographic applications such as EUV, VUV E-Beam, or like applications include repeat units based on the derivative of Meldrum's acid (i.e., 2,2-dimethyl-l,3-dioxane-4,6-dione) shown below:
• Meldrum's acid includes lactone as well as a ketal functionality.
• the Meldrum's acid will act as the switching group.
• the Meldrum's acid group will produce a dicarboxylic acid and acetone. This will make the resist film, initially insoluble, soluble in the basic developer.
• the derivatives of Meldrum's acid are more hydrolytically stable than the usual acetal and/or ketals used in prior resist formulations and therefore are expected to have better storage stability.
• a polymer comprises a repeat unit having a formula of:
• Z represents a repeat unit of a polymer backbone
• X is a linking group selected from the group consisting of alkylene, arylene, araalkylene, carbonyl, carboxyl, carboxyalkylene, oxy, oxyalkylene, and combinations thereof
• R is selected from the group consisting of hydrogen, alkyl, aryl, and cycloalkyl groups with the proviso that X and R are not part of the same ring system.
• a photoresist composition comprises a polymer comprising a repeat unit having a formula of:
• Z represents a repeat unit of a polymer backbone
• X is a linking group selected from the group consisting of alkylene, arylene, araalkylene, carbonyl, carboxyl, carboxyalkylene, oxy, oxyalkylene, or a combination thereof
• R is selected from the group consisting of hydrogen, alkyl, aryl, and cycloalkyl groups with the proviso that X and R are not part of the same ring system; a photo-acid generator; and a solvent.
• a process for forming a relief image in a photoresist film comprises applying a photoresist composition onto a substrate to form the photoresist film, wherein the photoresist composition comprises a polymer comprising a repeat unit having a formula of:
• Z represents a repeat unit of a polymer backbone
• X is a linking group selected from the group consisting of alkylene, arylene, araalkylene, carbonyl, carboxyl, carboxyalkylene, oxy, oxyalkylene, and combinations thereof
• R is selected from the group consisting of hydrogen, alkyl, aryl, and cycloalkyl groups with the proviso that X and R are not part of the same ring system, a photo-acid generator, and a solvent; exposing the film to radiation using a radiation source; and developing the photoresist film to form the relief image.
• FIG. 1 graphically illustrates contrast curves at various post exposure bake temperatures for a photoresist composition prepared in accordance with the present invention.
• FIG. 2 illustrates scanning electron micrographs of a patterned photoresist composition prepared in accordance with the present invention and imaged on a 248 nm exposure tool.
• FIG. 3 graphically illustrates a mass spectrum of outgassing molecules during EUV exposure of a photoresist composition prepared in accordance with the present invention.
• FIG. 4 illustrates scanning electron micrographs of a patterned photoresist composition prepared in accordance with the present invention and imaged on an EUV exposure tool.
• a monomer includes not only a single monomer but also a combination or mixture of two or more monomers that may or may not be the same
• a photo-acid generator includes a combination or mixture of two or more photo-acid generators as well as a single photo-acid generator, and the like.
• alkyl refers to a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, such as methyl, ethyl, n- propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like, as well as cycloalkyl groups such as cyclopentyl, cyclohexyl, and the like.
• alkylene refers to a difunctional saturated branched or unbranched hydrocarbon chain containing from 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, and includes, for example, methylene( — CH2 — ), ethylene( — CH2 — CH 2 — ), propylene( — CH 2 -CH 2 -CH 2 - ), 2-methylpropylene(— CH 2 - CH(CH 3 )- CH 2 - ), hexylene(—
• aryl refers to an aromatic moiety containing 1 to 5 aromatic rings.
• the rings may be fused or linked.
• Aryl groups are optionally substituted with one or more inert, nonhydrogen substituents per ring; suitable inert, nonhydrogen substituents include, for example, halo, haloalkyl (preferably halo-substituted lower alkyl), alkyl (preferably lower alkyl), alkoxy (preferably lower alkoxy), and the like.
• aryl is also intended to include heteroaromatic moieties, i.e., aromatic heterocycles. Generally, although not necessarily, the heteroatoms will be nitrogen, oxygen, or sulfur.
• polymer is used to refer to a chemical compound that comprises linked monomers and that may be linear, branched, or crosslinked.
• the polymer may be a homopolymer or a copolymer.
• photogenerated acid and “photo-acid” are used interchangeably herein to refer to the acid that is created upon exposure of the present compositions to radiation, i.e., as a result of the radiation sensitive photo-acid generator in the compositions.
• the polymer includes repeating units of a monomer based on a derivative of Meldrum's acid (i.e., 2,2- dimethyl- l,3-dioxane-4,6-dione) as shown in Formula (I) below, which includes both lactone and ketal functionalities.
• Meldrum's acid i.e., 2,2- dimethyl- l,3-dioxane-4,6-dione
• the lactone and ketal functionalities provided by the derivative of Meldrum's acid will act as the switching group.
• the Meldrum's acid group will produce a dicarboxylic acid and acetone. This will make the photoresist film, initially insoluble, soluble in a basic developer.
• the derivatives of Meldrum's acid have been discovered to be more hydrolytically stable than the usual acetals and/or ketals used in current low energy photoresist formulations and therefore are expected to have better storage stability.
• the polymer includes one or more repeat units based on a derivative of Meldrum's acid as shown by the following formula (II):
• Z represents a repeat unit of a polymer backbone
• X is a linking group selected from the group consisting of alkylene, arylene, araalkylene, carbonyl, carboxyl, carboxyalkylene, oxy, oxyalkylene, and a combination thereof
• R is selected from the group consisting of hydrogen, alkyl, aryl, and cycloalkyl groups with the proviso that X and R are not part of the same ring system.
• Polymers including the repeating unit as defined in formula (II) may include co-monomers that contain aqueous base soluble groups such as phenols, fluoroalcohols and/or polar functionalities such as lactones, anhydrides, alcohol groups, sulfonamide groups, other acid labile groups and the like.
• aqueous base soluble groups such as phenols, fluoroalcohols and/or polar functionalities such as lactones, anhydrides, alcohol groups, sulfonamide groups, other acid labile groups and the like.
• the ratios of the different monomeric units are not intended to be limited.
• Example 4 below details synthesis of a poly[4-hydroxystyrene-co-2,2- dimethyl-5-(4-vinylbenzyl)-l,3-dioxane-4,6-dione] copolymer.
• the ratio of m : n depicted in the example was 75:25 (wherein n represents the derivative of Meldrum's Acid as defined by Formula II), it should be apparent in view of this disclosure that by varying the monomer ratio one can obtain a copolymer wherein the ratio of m : n is at a ratio of greater than 0 to 99.99 mol% : 0.01 to less than 100 mol%, respectively.
• the m : n ratio is greater than 50 to less than 100 mo% : greater than 0 to less than 50 mol%, respectively.
• the m : n ratio is greater than 60 to less than 90 mo% : greater than 10 to less than 40 mol%, respectively.
• the number of different monomers is not intended to be limited. Higher order polymers such as terpolymers and the like can also be made.
• the molecular weight is 1 ,000 to 100,000 Daltons, and in other embodiments, the molecular weight is 5,000 to 10,000 Daltons.
• Monomers having the structure of formulae (II) may be readily synthesized using methods described in the pertinent texts and literature, or as known to those of ordinary skill in the art. Methods for synthesizing representative monomers and polymers are described in the Examples.
• copolymers that include a repeat unit having the structure of formula (II) may be prepared by radical copolymerization using a suitable free radical initiator. Radical polymerization is easy to run, economical, and highly suited for preparation of resist polymers.
• the initiator may be any conventional free radical-generating polymerization initiator.
• Suitable initiators include peroxides such as O-t-amyl-O- (2ethylhexyl)monoperoxycarbonate, dipropylperoxydicarbonate, and benzoyl peroxide (BPO), as well as azo compounds such as azobisisobutyronitrile (AIBN), 2,2'-azobis(2- amidino-propane)dihydrochloride, and 2,2'-azobis(isobutyramide) dihydrate.
• the initiator is generally present in the polymerization mixture in an amount of from about 0.2 to 20 mol % relative to the monomers.
• the polymers can be characterized by Gel Permeation Chromatography (GPC), Thermo Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Nuclear Magnetic Resonance spectroscopy (NMR).
• GPC Gel Permeation Chromatography
• TGA Thermo Gravimetric Analysis
• DSC Differential Scanning Calorimetry
• NMR Nuclear Magnetic Resonance spectroscopy
• the present invention also provides a photoresist composition
• a photoresist composition comprising a photoresist polymer that includes repeat units of Formula (II), a photo-acid generator, and an organic solvent.
• photo-acid generators can be used in the composition of the present invention.
• the photosensitive acid generators used in the photoresist compositions may be any suitable photosensitive acid generator known in the photoresist art that is compatible with the other components of the photoresist composition.
• Examples of preferred photoresist acid generators (PAGs) include: ⁇ -(trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3- dicarboximide (MDT), onium salts, aromatic diazonium salts, sulfonium salts, diaryliodonium salts, and sulfonic acid esters of N-hydroxyamides or -imides, as disclosed in
• a PAG that produces a weaker acid such as dodecane sulfonate of N-hydroxy-naphthalimide (DDSN) may be used. Combinations of PAGs may be used as well.
• DDSN dodecane sulfonate of N-hydroxy-naphthalimide
• suitable acid generators have a high thermal stability (typically to temperatures greater than 140° C.) so they are not degraded during pre-exposure processing.
• suitable PAGs include other sulfonate salts as well as sulfonated esters and sulfonyloxy ketones. See U.S. Pat. No. 5,344,742 to Sinta et al. and J.
• Onium salts are also generally preferred acid generators of compositions of the invention.
• Onium salts that contain weakly nucleophilic anions have been found to be particularly suitable. Examples of such anions are the halogen complex anions of divalent to heptavalent metals or nonmetals, for example, Sb, B, P, and As.
• onium salts examples include aryl-diazonium salts, halonium salts, aromatic sulfonium, salts and sulfoxonium salts or selenium salts (e.g., triarylsulfonium and diaryliodonium hexafluoroantimonates, hexafluoroarsenates, and trifluoromethanesulfonates).
• aryl-diazonium salts examples include aryl-diazonium salts, halonium salts, aromatic sulfonium, salts and sulfoxonium salts or selenium salts (e.g., triarylsulfonium and diaryliodonium hexafluoroantimonates, hexafluoroarsenates, and trifluoromethanesulfonates).
• preferred onium salts can be found in U.S. Pat. Nos. 4,442,197, 4,603,101, and 4,62
• Suitable s-triazine acid generators are disclosed, for example, in U.S. Pat. No. 4,189,323.
• Still other suitable acid generators include, but are not limited to, N- camphorsulfonyloxynaphthalimide; N-pentafluorophenylsulfonyloxynaphthalimide, ionic iodonium sulfonates (e.g., diaryl iodonium (alkyl or aryl) sulfonate and bis-(di-t- butylphenyl)iodonium camphanylsulfonate); ionic iodonium perfluoroalkanesulfonates (such as di-(4-t-butylphenyl)iodonium pentafluorooctane sulfonate, "IPFOS”), aryl (e.g., phenyl or benzyl) triflates and derivatives and analogs thereof (e.g., triphenylsulfonium triflate or bis- (t-butylphenyl)i
• the choice of solvent is governed by many factors and is not limited to the solubility and miscibility of resist components, the coating process, and safety and environmental regulations. Additionally, inertness to other resist components is desirable. It is also desirable that the solvent possess the appropriate volatility to allow uniform coating of films, yet also allow significant reduction or complete removal of residual solvent during the post- application bake process. See, e.g., Introduction to Microlithography, Eds. Thompson et al., cited previously.
• the photoresist compositions of the invention generally include a casting solvent to dissolve the other components so that the overall composition may be applied evenly on the substrate surface to provide a defect-free coating.
• the solvent used in the imaging layer photoresist is preferably not a solvent to the underlayer materials; otherwise the unwanted intermixing may occur.
• suitable casting solvents include: ethoxyethylpropionate (EEP); a combination of EEP and ⁇ -butyrolactone
• solvents may generally be chosen from ether-, ester-, hydroxyl-, and ketone-containing compounds, or mixtures of these compounds.
• appropriate solvents include: cyclopentanone; cyclohexanone; lactate esters, such as ethyl lactate; alkylene glycol alkyl ether esters, such as propylene glycol methyl ether acetate; alkylene glycol monoalkyl esters, such as methyl cellosolve; butyl acetate; 2-ethoxyethanol; and ethyl 3-ethoxypropionate.
• Preferred solvents include PGMEA, EEP, and their mixtures.
• solvents are for illustrative purposes only and should not be viewed as being comprehensive, nor should the choice of solvent be viewed as limiting to the invention in any way. Those skilled in the art will recognize that any number of solvents or solvent mixtures may be used. Greater than 50 percent of the total mass of the resist formulation is typically composed of the solvent, preferably greater than 80 percent.
• the photoresist polymer represents up to about 99 wt. % of the solids included in the composition, and the photo-acid generator represents approximately 0.5-10 wt. % of the solids contained in the composition. Other components and additives may also be present.
• a positive photoresist composition may include a dissolution inhibitor; and a negative photoresist composition will include a crosslinking agent. If dissolution inhibitors and crosslinking agents are present, they will typically be present in the range of about 1 wt. % to 40 wt. %, preferably about 5 wt. % to 30 wt. %, of the total solids. Suitable dissolution inhibitors will be known to those skilled in the art and/or described in the pertinent literature.
• Preferred dissolution inhibitors have high solubility in both the resist composition and the solvent used to prepare solutions of the resist composition (e.g., propylene glycol methyl ether acetate, or "PGMEA”), exhibit strong dissolution inhibition, have a high exposed dissolution rate, are substantially transparent at the wavelength of interest, exhibit a moderating influence on Tg, strong etch resistance, and display good thermal stability (i.e., stability at temperatures of about 140 C. or greater).
• PMEA propylene glycol methyl ether acetate
• Suitable dissolution inhibitors include, but are not limited to, bisphenol A derivatives and carbonate derivatives, for example, bisphenol A derivatives wherein one or both hydroxyl moieties are converted to a t-butoxy substituent or a derivative thereof, such as a t-butoxycarbonyl or t- butoxycarbonylmethyl group; fluorinated bisphenol A derivatives such as CF3-bisphenol A — OCH2(CO) — O-tBu (6F-bisphenol A protected with a t-butoxycarbonylmethyl group); normal or branched chain acetal groups such as 1-ethoxyethyl, 1-propoxyethyl, 1-n- butoxyethyl, 1-isobutoxy-ethyl, 1 -t-butyloxy ethyl, and 1-t-amyloxy ethyl groups; cyclic acetal groups such as tetrahydrofuranyl, tetrahydropyranyl, and 2-methoxyt
• Examples of such compounds include lower alkyl esters of cholic, ursocholic, and lithocholic acid, including methyl cholate, methyl lithocholate, methyl ursocholate, t-butyl cholate, t-butyl lithocholate, t-butyl ursocholate, and the like (see, e.g., Allen et al. (1995) J. Photopolym. Sci.
• customary additives include dyes that may be used to adjust the optical density of the formulated resist, and sensitizers that enhance the activity of photo-acid generators by absorbing radiation and transferring it to the photo-acid generator.
• aromatics such as functionalized benzenes, pyridines, pyrimidines, biphenylenes, indenes, naphthalenes, anthracenes, coumarins, anthraquinones, other aromatic ketones, and derivatives and analogs of any of the foregoing.
• aromatics such as functionalized benzenes, pyridines, pyrimidines, biphenylenes, indenes, naphthalenes, anthracenes, coumarins, anthraquinones, other aromatic ketones, and derivatives and analogs of any of the foregoing.
• a wide variety of compounds with varying basicities may be used as stabilizers and acid- diffusion controlling additives.
• nitrogenous compounds such as aliphatic primary, secondary, and tertiary amines; cyclic amines such as piperidines; pyrimidines; morpholines; aromatic heterocyclics such as pyridines; pyrimidines; purines; imines such as diazabicycloundecene; guanidines; imides; amides; and others.
• Ammonium salts may also be used, including ammonium, primary, secondary, tertiary, and quaternary alkyl- and arylammonium salts of alkoxides (e.g., hydroxide, phenolates, carboxylates, aryl and alkyl sulfonates, sulfonamides, and others).
• alkoxides e.g., hydroxide, phenolates, carboxylates, aryl and alkyl sulfonates, sulfonamides, and others.
• Other cationic nitrogenous compounds including pyridinium salts and salts of other heterocyclic nitrogenous compounds with anions such as alkoxides (e.g., hydroxide, phenolates, carboxylates, aryl and alkyl sulfonates, sulfonamides, and the like), may also be employed.
• Surfactants may be used to improve coating uniformity, and include a wide variety of
• anti-foaming agents may be employed to suppress coating defects.
• Adhesion promoters may be used as well; again, a wide variety of compounds may be employed to serve this function.
• a wide variety of monomeric, oligomeric, and polymeric plasticizers (such as oligo- and polyethyleneglycol ethers, cycloaliphatic esters, and non-acid reactive steroidally derived materials) may be used as plasticizers if desired.
• plasticizers such as oligo- and polyethyleneglycol ethers, cycloaliphatic esters, and non-acid reactive steroidally derived materials
• Exemplary radiation or irradiuation sources which are useful for lithographically forming the photoresist pattern include, without limitation, VUV (157 nm), ArF (193 nm), KrF (248 nm), EUV (13 nm), E-beam, X-ray and ion beam.
• the irradiation energy is in the range of from about 1 mJ/cm 2to about 100 mJ/cm 2.
• the present invention also provides a semiconductor device, which is manufactured using the photoresist composition described above.
• parts are parts by weight, temperature is in 0 C and pressure is at or near atmospheric. Additionally, all starting materials were obtained commercially or were synthesized using known procedures. 4-(2- hydroxyhexafluoro-2-propyl)styrene monomer was obtained from Central Glass Company.
• IH and 13C NMR spectra were obtained at room temperature on an Avance 400 spectrometer.
• Quantitative 13C NMR was run at room temperature in acetone-d6 in an inverse-gated lH-decoupled mode using Cr(acac)3 as a relaxation agent on an Avance 400 spectrometer.
• 19F NMR (379 MHz) spectra were also obtained using a Bruker Avance 400 spectrometer.
• Thermo-gravimetric analysis (TGA) was performed at a heating rate of 5°C/min in N2 on a TA Instrument Hi-Res TGA 2950 Thermogravimetric Analyzer.
• DSC Differential scanning calorimetry
• TMAH aqueous tetramethylammonium hydroxide
• 193 nm exposures were carried out on an ISI mini-stepper with 0.60 NA.
• 248 nm exposures were carried out on an ASML 0.60 NA stepper.
• E-beam exposures were carried out on a Leica 100 kV exposure tool.
• EUV exposures were carried out on a prototype EUV tool at Lawrence Berkeley National Laboratory in Berkeley, CA.
• Mono(2-methylacryloyloxy)ethyl succinate (3.9 mL, 20 mL), Meldrum's acid (3.20 g, 22 mmol), 4-dimethylaminopyridine (3.85 g, 32 mmol) and phenothiazine (46 mg) were dissolved in dichloromethane ( 100 mL) in a 250 mL 3-necked round bottomed flask equipped with a thermometer, nitrogen/vacuum inlet, and an addition flask containing a solution of dicyclohexylcarbodiimide (DCC) (4.74 g, 23 mmol) in dichloromethane (50 mL).
• DCC dicyclohexylcarbodiimide
• the photoresist composition of Example 6 was spin coated onto multiple silicon wafers using a post apply bake temperature was l lOoC for 60 seconds.
• FIG. 1 graphically illustrates contrast curves for the photoresist composition at various post exposure temperatures for 90 seconds. Thickness as a function of exposure dose was measured for the different post exposed bake temperatures.
• Example 6 the photoresist composition of Example 6 was spin coated onto a silicon wafer coated with 62 nm of an anti reflection coating (Brewer Science DUV- 42P) at a thickness of
• FIG. 2 illustrates scanning electron micrographs of a 1 : 1 line space pairs for the patterned photoresist composition at 150 nm and 160 nm feature sizes.
• EXAMPLE 7 A Photoresist Composition based on Poly(4HS-co-VBMMA) (75:25) for EUV exposure.
• FIG. 3 graphically illustrates the mass spectrum presented, which clearly indicates that there are no fragments other than acetone emanating from the polymer. All the other fragments can be attributed to the photo-acid generator.
• FIG. 4 illustrates scanning electron micrographs of the patterned photoresist composition.
• the photoresist composition analogous to Example 7 was spin coated onto a silicon wafer already coated with 62 nm of an anti reflection coating (Brewer Science DUV- 42P) at a thickness of 105 nm and imaged using an EUV prototype tool at an exposure does of 67.38 mJ.
• the photoresist composition was post apply baked at 1 1 O 0 C for 60 seconds, post exposure baked at 100 0 C for 60 seconds, and developed for 60 seconds in an aqueous 0.26 N TMAH solution.
• the polymers herein advantageously enjoy the following properties: a.) the protecting groups do not deprotect inside the imaging tool under vacuum conditions; b.) if deprotected while being exposed, the fragments are attached to the polymer in some fashion so that they don't outgas; and c.) the fragments are light hydrocarbons with molecular weight ⁇ 100 atomic mass units (amu).

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