Photoresist pattern trimming composition and pattern forming method

Abstract

The photoresist pattern trimming composition comprises a polymer, an aromatic sulfonic acid and an organic solvent-based system, wherein the aromatic sulfonic acid has the general formula (I): #imgabs0# wherein: Ar 1 Represents an aromatic group; R 1 independently represent a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted heteroalkyl group, a substituted or unsubstituted carbocyclic aromatic group, a substituted or unsubstituted heterocyclic aromatic group, a substituted or unsubstituted alkoxy group, or a combination thereof, wherein the adjacent R 1 Group and Ar 1 optionally together form a fused ring structure; a represents an integer of 2 or greater; and b represents an integer of 1 or greater, provided that a+b is at least 3 and not greater than Ar 1 The total number of available aromatic carbon atoms, and R 1 Two or more of are independently fluorine atoms or fluoroalkyl groups directly bonded to a carbon atom of the aromatic ring.

Description

Background Art

[0001] The present invention relates generally to the manufacture of electronic devices. More specifically, the present invention relates to photoresist pattern trimming compositions and to pattern forming methods using such compositions. The compositions and methods are particularly useful for forming fine lithographic patterns.

[0002] In the semiconductor manufacturing industry, photoresist materials are used to transfer images to one or more underlying layers, such as metal, semiconductor or dielectric layers, disposed on a semiconductor substrate, as well as the substrate itself. In order to increase the integration density of semiconductor devices and allow the formation of structures with dimensions in the nanometer range, photoresists and photolithography processing tools with high-resolution capabilities have been and continue to be developed.

[0003] Positive chemically enhanced photoresists are generally used for high resolution processing. Such resists typically use resins and photoacid generators with acid-labile leaving groups. Patterned exposure to activating radiation through a photomask causes the acid generator to form an acid, which, during post-exposure baking, causes the acid-labile groups in the exposed regions of the resin to break. This creates a difference in solubility characteristics between the exposed and unexposed regions of the resist in an alkaline developer aqueous solution. In the positive development (PTD) process, the exposed regions of the resist are soluble in aqueous alkaline developers and removed from the substrate surface, while the unexposed regions that are insoluble in the developer are retained after development to form a positive image.

[0004] Lithographic scaling is usually achieved by increasing the numerical aperture of the optical exposure tool and using a shorter exposure wavelength. In order to form a finer photoresist pattern than can be obtained only by direct imaging, a photoresist pattern trimming process has been proposed, for example, in U.S. Patent Application Publication Nos. US 20130171574 A1, US 20130171825 A1, US 2014 / 0186772 A1 and US 2016 / 0187783 A1. The photoresist trimming process typically involves contacting a photoresist pattern including a polymer with an acid-labile group with a composition containing an acid or a hot acid generator. The acid or the acid generated deprotects the surface area of ​​the resist pattern, and then, for example, removes the surface area by contacting with a developer solution. This allows trimming the photoresist pattern so that, for example, a finer resist line or column pattern is produced compared to when only direct imaging is used. However, as pattern sizes and device geometries decrease, trimming process considerations, such as line width roughness, pattern collapse margin, and coating defect levels, become increasingly important to minimize defects that could adversely affect the performance and / or yield of the resulting electronic devices.

[0005] There is a need in the art for photoresist pattern trimming compositions and pattern forming methods for use in electronic device fabrication that address one or more problems associated with the prior art. Summary of the invention

[0006] According to a first aspect of the present invention, a pattern modification composition is provided. The composition comprises a polymer, an aromatic sulfonic acid and an organic solvent-based system, wherein the aromatic sulfonic acid has a general formula (I):

[0007]

[0008] Where: Ar 1 Represents an aromatic group; R 1 independently represent a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted heteroalkyl group, a substituted or unsubstituted carbocyclic aromatic group, a substituted or unsubstituted heterocyclic aromatic group, a substituted or unsubstituted alkoxy group, or a combination thereof, wherein the adjacent R 1 Group and Ar 1 optionally together form a fused ring structure; a represents an integer of 2 or greater; and b represents an integer of 1 or greater, provided that a+b is at least 3 and not greater than Ar 1 The total number of available aromatic carbon atoms, and R 1 Two or more of are independently fluorine atoms or fluoroalkyl groups directly bonded to a carbon atom of the aromatic ring.

[0009] A pattern forming method is also provided. The method includes: (a) providing a semiconductor substrate; (b) forming a photoresist pattern on the semiconductor substrate, wherein the photoresist pattern is formed by a photoresist composition comprising: a polymer comprising an acid-labile group; and a photoacid generator; (c) applying a pattern trimming composition as described herein on the photoresist pattern; (d) heating the coated photoresist pattern; and (e) rinsing the coated and heated photoresist pattern with a rinse agent to remove residual pattern treatment composition. Preferred methods and compositions of the present invention can provide photoresist patterns having desired properties, such as one or more properties, including changes in critical dimension (ΔCD), line width roughness (LWR), pattern collapse margin (PCM), or coating defect rate.

[0010] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. Unless the context indicates otherwise, the singular forms "a / an" and "the" are intended to include both the singular and the plural. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be described with reference to the following drawings, in which like reference numerals represent like features, and in which:

[0012] Figure 1A -H shows an exemplary process flow for forming a pattern according to the present invention. DETAILED DESCRIPTION

[0013] Photoresist pattern trimming composition

[0014] The photoresist pattern trimming composition of the present invention comprises a system of a polymer, an aromatic sulfonic acid and an organic-based solvent, and may comprise one or more optional additional components. The polymer allows the composition to be coated on the photoresist pattern in the form of a layer having a desired thickness. The polymer should have good solubility in the rinse to be used in the patterning process. For example, the polymer can be soluble in alkaline aqueous solutions, such as those typically used as photoresist developers, preferably aqueous quaternary ammonium hydroxide solutions, such as tetramethylammonium hydroxide (TMAH) aqueous solutions (e.g., 0.26NTMAH). In order to minimize residual defects from the pattern trimming composition, the dissolution rate of the dried layer of the trimming composition in the rinse to be applied should be greater than the dissolution rate of the photoresist pattern in the rinse. The polymer typically exhibits a 0.26N TMAH solution in the rinse. / second or higher, preferably The polymer should be soluble in the solvent system of the trimming composition.

[0015] The polymer may be formed from one or more monomers selected from, for example, monomers having ethylenically unsaturated polymerizable double bonds, such as: (meth)acrylate monomers, such as isopropyl (meth)acrylate and n-butyl (meth)acrylate; (meth)acrylic acid; vinyl aromatic monomers, such as styrene, hydroxystyrene, vinyl naphthalene and acenaphthylene; vinyl alcohol; vinyl chloride; vinyl pyrrolidone; vinyl pyridine; vinyl amine; vinyl acetal; and combinations thereof. The polymer preferably includes one or more repeating units formed from vinyl aromatic monomers. Preferably, the polymer contains one or more functional groups selected from, for example, hydroxyl groups, acid groups (such as carboxyl groups), sulfonic acids and sulfonamides, silanols, fluoroalcohols (such as hexafluoroisopropanol [-C(CF3)2OH]), anhydrous substances, lactones, esters, ethers, allylamines, pyrrolidone and combinations thereof. Among them, -C(CF3)2OH and acid groups (such as carboxyl groups), sulfonic acids and sulfonamides are particularly preferred. The polymer may be a homopolymer or a copolymer having a plurality of different repeating units, such as two, three, four or more different repeating units. In one aspect, the repeating units of the polymer are all formed from (meth)acrylate monomers, all formed from (vinyl)aromatic monomers, or all formed from (meth)acrylate monomers and (vinyl)aromatic monomers. When the polymer includes more than one type of repeating unit, it typically takes the form of a random copolymer.

[0016] Suitable polymers according to the present invention include, for example, the following:

[0017]

[0018]

[0019]

[0020]

[0021] The trimming composition typically includes a single polymer, but may also optionally include one or more additional polymers. The content of the polymer in the composition will depend, for example, on the target thickness of the layer, with a higher polymer content being used when a thicker layer is desired. The polymer is typically present in the trimming composition in an amount of 80 to 99.9 wt%, more typically 90 to 99 wt% or 95 to 99 wt%, based on the total solids of the pattern trimming composition. The weight average molecular weight (Mw) of the polymer is typically less than 400,000, preferably 3000 to 50,000, more preferably 3000 to 25,000 as measured by GPC relative to polystyrene standards. Typically, the polymer will have a polydispersity index (PDI = Mw / Mn) of 3 or less, preferably 2 or less, as measured by GPC relative to polystyrene standards.

[0022] Suitable polymers for the finishing composition are commercially available and / or can be easily prepared by those skilled in the art. For example, the polymer can be synthesized by dissolving a selected monomer corresponding to the polymer unit in an organic solvent, adding a free radical polymerization initiator thereto, and performing thermal polymerization to form the polymer. Examples of suitable organic solvents that can be used for polymer polymerization include, for example, toluene, benzene, tetrahydrofuran, diethyl ether, dioxane, ethyl lactate, and methyl isobutyl carbinol. Suitable polymerization initiators include, for example, 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide.

[0023] The trimming composition further includes a non-polymeric aromatic sulfonic acid. In the case of a deprotection reaction based photoresist, the heated acid causes bond cleavage of the acid labile groups in the surface region of the photoresist pattern, increasing the solubility of the photoresist polymer in the rinse solution to be applied.

[0024] Aromatic sulfonic acids have the general formula (I):

[0025]

[0026] Among them, Ar 1 Represents an aromatic group, which may be carbocyclic, heterocyclic or a combination thereof. The aromatic group may be monocyclic, such as phenyl or pyridyl, or polycyclic, such as biphenyl, and may include fused aromatic rings, such as naphthyl, anthracenyl or pyrenyl, or a fused ring system having both aromatic and non-aromatic rings, such as 1,2,3,4-tetralin, 9,10-dihydroanthracene or fluorene. The aromatic group typically has 4 to 18 carbons, and preferably 6 to 14 carbons. Suitable aromatic groups include, but are not limited to: phenyl, biphenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, tetracenyl, triphenylene, tetraphenyl, benzo[f]tetraphenyl, benzo[m]tetraphenyl and benzo[k]tetraphenyl. Among them, phenyl is particularly preferred. R 1 independently represent a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group (C 1-12 ), substituted or unsubstituted heteroalkyl (C 1-12 ), substituted or unsubstituted carbocyclic aromatic group (C 6-12 ), substituted or unsubstituted heterocyclic aromatic group (C 4-12 ), substituted or unsubstituted alkoxy (C 1-12 ), or a combination thereof. Adjacent R 1 Group and Ar 1 Together they may optionally form a fused ring structure. 1 and independently represent a fluorine atom or a trifluoromethyl group.

[0027] Alkyl and heteroalkyl groups may be linear, branched or cyclic structures. The term "substituted" means that one or more of the hydrogen atoms are selected from hydroxyl, halogen, C 1-12 Alkyl, C 1-12 Heteroalkyl, C 1-12 Alkoxy, C 6-12 Aryl or C 4-12 A group in which the heteroaryl group is substituted with one or more substituents.

[0028] a represents an integer of 2 or more, preferably an integer of 2 to 4, and more preferably 2, and b represents an integer of 1 or more, preferably an integer of 1 to 2, and more preferably 1, with the proviso that a+b is at least 3 and not greater than Ar 1 Typically, a+b is 3 to 5. 1 Two or more of R are independently fluorine atoms or fluoroalkyl groups directly bonded to aromatic ring carbon atoms. Fluoroalkyl groups may be linear, branched, or cyclic, and typically have 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, and more preferably 1 or 2 carbon atoms, with trifluoromethyl being typical. When branched or cyclic, R 1 Will have a minimum of 3 carbon atoms. 1 is at least partially fluorinated, and preferably is perfluorinated. The aromatic sulfonic acid is typically present in an amount of about 0.01 to 20 wt % based on the total solids of the trimming composition.

[0029] Preferably, the aromatic sulfonic acid has the general formula II:

[0030]

[0031] Where: R 1 is as defined above; a represents an integer from 2 to 5, and R 1 Two or more of are independently fluorine atoms or fluoroalkyl groups.

[0032] Suitable exemplary aromatic sulfonic acids include the following:

[0033]

[0034]

[0035]

[0036]

[0037] The trimming composition further comprises an organic-based solvent system An organic solvent-based system comprising one or more different solvents. The term "organic-based" means that the solvent system comprises greater than 50 wt% organic solvent based on the total solvent of the trimming composition, more typically greater than 90 wt%, greater than 95 wt%, greater than 99 wt% or 100 wt% organic solvent based on the total solvent of the trimming composition. Suitable solvent materials for formulating and casting the trimming composition should exhibit good solubility characteristics for the non-solvent components of the trimming composition without significantly dissolving the underlying photoresist pattern, thereby minimizing intermixing with the photoresist pattern.

[0038] Suitable organic solvents for the trimming composition include, for example: alkyl esters, such as alkyl propionates, such as n-butyl propionate, n-pentyl propionate, n-hexyl propionate and n-heptyl propionate, and alkyl butyrates, such as n-butyl butyrate, isobutyl butyrate and isobutyl isobutyrate; ketones, such as 2,5-dimethyl-4-hexanone and 2,6-dimethyl-4-heptanone; aliphatic hydrocarbons, such as n-heptane, n-nonane, n-octane, n-decane, 2-methylheptane, 3-methylheptane, 3,3-dimethylhexane and 2,3,4-trimethylpentane, and fluorinated aliphatic hydrocarbons, such as perfluoroheptane; alcohols, such as linear, branched or cyclic C4-C9 monohydric alcohols, such as 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol and 4-octanol; 2,2,3,3,4,4-hexafluoro-1-butanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol and 2,2,3,3,4,4,5,5,6,6-decafluoro-1-hexanol and C5-C9 fluorinated diols, such as 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol and 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol; ethers, such as isopentyl ether and dipropylene glycol monomethyl ether; and mixtures containing one or more of these solvents.

[0039] When the photoresist pattern to be trimmed is formed by a vinyl aromatic polymer, such as a polymer containing styrene and / or hydroxystyrene units, the solvent system preferably comprises one or more monoether solvents. When processing a vinyl aromatic photoresist pattern, the use of a monoether-based solvent system can provide low top loss characteristics. As used herein, "vinyl aromatic" means a polymerized unit formed by a monomer in which an aromatic group is directly bonded to a vinyl group, such as styrene, hydroxystyrene, and vinylnaphthalene. "Vinyl aromatic polymer" means a polymer containing more than 50 mol%, more typically 50 to 90 mol% or 60 to 80 mol% of vinyl aromatic units based on the total units of the polymer.

[0040] Suitable monoether-containing solvent systems include one or more monoether solvents in a combined amount of 50 to 98 wt%, preferably 70 to 98 wt%, 80 to 98 wt% or 90 to 98 wt% based on the solvent system. Preferred monoether solvents include alkyl monoethers and aromatic monoethers, particularly preferably those with a total carbon number of 6 to 16. Suitable alkyl monoethers include, for example, 1,4-cineole, 1,8-cineole, pinene oxide, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, di-n-amyl ether, diisoamyl ether, dihexyl ether, diheptyl ether and dioctyl ether, wherein diisoamyl ether is preferred. Suitable aromatic monoethers include, for example, anisole, ethyl benzyl ether, diphenyl ether, dibenzyl ether and phenethyl ether, wherein anisole is preferred.

[0041] The ether-containing solvent system preferably further comprises one or more alcohol and / or ester solvents. For certain trimming compositions, alcohol and / or ester solvents can provide enhanced solubility relative to the solid components. Suitable alcohol solvents include, for example, linear, branched or cyclic C4-C8 monohydric alcohols such as 1-butanol, 2-butanol, isobutanol, tert-butanol, 3-methyl-1-butanol, 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 1-hexanol, 1-heptanol, 2-hexanol, 2-heptanol, 3-hexanol, 3-heptanol, 1-octanol, 2-octanol, 3-octanol, 4-octanol, 2,2,3,3,4,4-hexafluoro-1-butan ... , 2,3,3,4,4,5,5-octafluoro-1-pentanol and 2,2,3,3,4,4,5,5,6,6-decafluoro-1-hexanol; and C5-C9 fluorinated diols, such as 2,2,3,3,4,4-hexafluoro-1,5-pentanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol and 2,2,3,3,4,4,5,5,6,6,7,7-twelve fluoro-1,8-octanediol. The alcohol solvent is preferably a C4-C8 monohydric alcohol, of which 4-methyl-2-pentanol is preferred. Suitable ester solvents include, for example, alkyl esters having a total carbon number of 4 to 10, such as alkyl propionates, such as n-butyl propionate, n-pentyl propionate, n-hexyl propionate, and n-heptyl propionate, and alkyl butyrates, such as n-butyl butyrate, isobutyl butyrate, and isobutyl isobutyrate. If used in an ether-containing solvent system, one or more alcohol and / or ester solvents are present in a combined amount of 2 to 50 wt %, more typically 2 to 30 wt %, based on the solvent system.

[0042] The ether-containing solvent system may include one or more additional solvents selected from, for example, one or more of the following: ketones, such as 2,5-dimethyl-4-hexanone and 2,6-dimethyl-4-heptanone; aliphatic hydrocarbons, such as n-heptane, 2-methylheptane, 3-methylheptane, 3,3-dimethylhexane, 2,3,4-trimethylpentane, n-octane, n-nonane and n-decane; fluorinated aliphatic hydrocarbons, such as perfluoroheptane; and diethers, such as dipropylene glycol monomethyl ether. Such additional solvents, if used, are typically present in a combined amount of 1 to 20 wt % based on the solvent system.

[0043] Particularly preferred organic solvent-based systems contain one or more monoether solvents in a combined amount of 70 to 98 wt % based on the solvent system, and one or more alcohol and / or ester solvents in a combined amount of 2 to 30 wt % based on the solvent system. The one or more solvents constituting the organic solvent-based system are typically present in the outer coating composition in a combined amount of 90 to 99 wt %, preferably 95 to 99 wt %, based on the outer coating composition.

[0044] The finishing composition may further include one or more additional, optional components, such as surfactants. Typical surfactants include those that exhibit amphiphilic properties, meaning that they can be both hydrophilic and hydrophobic. Amphiphilic surfactants have one or more hydrophilic head groups (which have a strong affinity for water) and a long hydrophobic tail (which is organophilic and repels water). Suitable surfactants can be ionic (i.e., anionic, cationic) or nonionic. Additional examples of surfactants include silicone surfactants, poly(oxyalkylene) surfactants, and fluorochemical surfactants. Suitable nonionic surfactants include, but are not limited to, octyl and nonylphenol ethoxylates, such as X-114, X-100, X-45, X-15, and branched secondary alcohol ethoxylates, such as TERGITOL TM TMN-6 (Dow Chemical Company, Midland, Michigan, USA). Still other exemplary surfactants include, alcohol (primary and secondary) ethoxylates, amine ethoxylates, glucosides, glucosamine, polyethylene glycol, poly (ethylene glycol-co-propylene glycol), or other surfactants disclosed in the 2000 North American edition of McCutcheon's Emulsifiers and Detergents, published by Manufacturers Confectioners Publishing Co. of Glen Rock, NJ. Nonionic surfactants that are derivatives of acetylenic diols may also be suitable. Such surfactants are commercially available from Air Products and Chemicals, Inc. of Allentown, Pennsylvania and are sold under the trade name and Additional suitable surfactants include other polymer compounds, such as triblock EO-PO-EO copolymers 25R2, L121, L123, L31, L81, L101 and P123 (BASF, Inc.). If used, such surfactants and other optional additives are typically present in the composition in small amounts, such as 0.01 to 10 wt % based on the total solids of the trimming composition. The trimming composition is preferably free of crosslinking agents because such materials can cause the size of the photoresist pattern to increase. The trimming composition may be free of polymeric acids and polymeric acid generators.

[0045] The trimming composition can be prepared according to known procedures. For example, the composition can be prepared by dissolving the solid components of the composition in the solvent component. The desired total solid content of the composition will depend on a variety of factors, such as the desired final layer thickness. Preferably, the solid content of the trimming composition is 1 wt% to 10 wt%, more preferably 1 wt% to 5 wt%, based on the total weight of the composition.

[0046] Patterning method

[0047] Now refer to Figure 1A -H describes a process according to the invention, said Figure 1A -H shows an exemplary process flow of a pattern forming method according to the present invention. Although the process flow shown describes a patterning process in which a photoresist pattern is transferred to an underlying substrate using a single resist mask, it should be clear that the method can be used for other lithography processes, such as double patterning processes such as lithography-lithography-etch (LLE), lithography-etch-lithography-etch (LELE) or self-aligned double patterning (SADP), such as ion implantation masking, or any other lithography process in which such photoresist pattern processing would be beneficial.

[0048] Figure 1A A cross section of a substrate 100 is depicted, which may include various layers and features. The substrate may be a material such as a semiconductor, such as silicon or a compound semiconductor (e.g., III-V or II-VI), glass, quartz, ceramic, copper, etc. Typically, the substrate is a semiconductor wafer, such as a single crystal silicon or a compound semiconductor wafer, and may have one or more layers and patterned features formed on its surface. One or more layers 102 to be patterned may be provided on the substrate 100. Optionally, for example, when it is desired to form grooves in the substrate material, the underlying base substrate material itself may be patterned. In the case where the base substrate material itself is patterned, it should be considered that the pattern is formed in the layer of the substrate.

[0049] The layers may include, for example, one or more conductive layers, such as aluminum, copper, molybdenum, tantalum, titanium, tungsten, alloys of these metals, nitrides or silicides, layers of doped amorphous silicon or doped polycrystalline silicon; one or more dielectric layers, such as layers of silicon oxide, silicon nitride, silicon oxynitride or metal oxide; semiconductor layers, such as single crystal silicon; and combinations thereof. The layers to be etched may be formed by various techniques, such as chemical vapor deposition (CVD), such as plasma enhanced CVD (PECVD), low pressure CVD (LPCVD) or epitaxial growth, physical vapor deposition (PVD), such as sputtering or evaporation, or electroplating. The specific thickness of the one or more layers 102 to be etched will vary depending on the material and the specific device being formed.

[0050] Depending on the specific layer to be etched, the film thickness, and the photolithographic materials and processes to be used, it may be desirable to arrange a hard mask layer 103 and / or a bottom anti-reflective coating (BARC) 104 on the layer 102, on which a photoresist layer 106 is coated. For example, for very thin resist layers, it may be necessary to use a hard mask layer, where the layer to be etched requires a significant etching depth, and / or where a specific etchant has poor resist selectivity. In the case of using a hard mask layer, the resist pattern to be formed can be transferred to the hard mask layer 103, which can then be used as a mask for etching the lower layer 102. Suitable hard mask materials and formation methods are known in the art. Typical materials include, for example, tungsten, titanium, titanium nitride, titanium oxide, zirconium oxide, aluminum oxide, aluminum oxynitride, hafnium oxide, amorphous carbon, spin-on carbon (SOC), silicon oxynitride, and silicon nitride. The hard mask layer can include a single layer or multiple layers with different materials. The hard mask layer can be formed, for example, by CVD, PVD or spin coating techniques.

[0051] Bottom anti-reflective coatings may be desirable in cases where the substrate and / or underlying layers reflect a large amount of incident radiation during photoresist exposure, so that the quality of the pattern formed is adversely affected. Such coatings can improve focus depth, exposure latitude, line width uniformity, and CD control. Anti-reflective coatings are typically used when the resist is exposed to deep ultraviolet radiation (300nm or less), such as KrF (248nm), ArF (193nm), or EUV (13.5nm) radiation. Anti-reflective coatings can include a single layer or multiple different layers. Suitable anti-reflective materials and methods of formation are known in the art. Anti-reflective materials are commercially available, such as those sold by the Specialty Products Division of DowDupont (Wilmington, Delaware, USA) as AR TM Those sold under trade names, such as AR TM 3. AR TM 40A and AR TM 124 Anti-reflective material.

[0052] The photoresist layer 106 is formed from a photoresist composition, typically a chemically enhanced photosensitive composition comprising a polymer having an acid-labile group, a photoacid generator, and a solvent. Suitable photoresist compositions are well known in the art. Preferably, the photoresist polymer is formed from monomers selected from vinyl aromatics (e.g., styrene and hydroxystyrene), (meth)acrylates, norbornene, and combinations thereof. In a preferred aspect, the photoresist polymer is based on vinyl aromatics, wherein more than 50 mol % of the polymerized units in the polymer, typically more than 80 mol % of the polymerized units in the polymer are formed from vinyl aromatic monomers.

[0053] The photoresist layer is disposed on the substrate above the antireflective layer 104 (if present). The photoresist composition can be applied to the substrate by spin coating, dip coating, roller coating or other conventional coating techniques. Among them, spin coating is typical. For spin coating, the solid content of the coating solution can be adjusted to provide a desired film thickness based on the specific coating equipment used, the viscosity of the solution, the speed of the coating tool and the amount of time allowed for spinning. The typical thickness of the photoresist layer 106 is about 500 to 1000 μm.

[0054] Next, the photoresist layer 106 is typically soft baked to minimize the solvent content in the layer, thereby forming a tack-free coating and improving the adhesion of the layer to the substrate. The soft bake can be performed on a hot plate or in an oven, where a hot plate is typical. The soft bake temperature and time will depend on, for example, the specific material and thickness of the photoresist. A typical soft bake is performed at a temperature of about 90° C. to 150° C. and for a time of about 30 to 90 seconds.

[0055] Next, the photoresist layer 106 is exposed to activating radiation 108 through a photomask 110 to produce a solubility difference between the exposed and unexposed areas. The exposure of the photoresist composition to the radiation that activates the composition mentioned herein indicates that the radiation can form a latent image in the photoresist composition. The photomask has optically transparent and optically opaque regions, corresponding to the regions to be exposed and unexposed by the activating radiation in the resist layer, respectively. The exposure wavelength is typically below 400nm, below 300nm (such as deep UV (248nm)), 193nm or EUV wavelength (e.g., 13.5nm). In a preferred aspect, the exposure wavelength is deep UV or EUV lithography. The exposure energy is typically about 10 to 80mJ / cm 2 , which depends on, for example, the exposure tool and the components of the photosensitive composition.

[0056] After exposing the photoresist layer 106, a post-exposure bake (PEB) is typically performed. The PEB can be performed, for example, on a hot plate or in an oven. The conditions of the PEB will depend, for example, on the specific photoresist composition and layer thickness. The PEB is typically performed at a temperature of about 80° C. to 150° C. and for a time of about 30 to 90 seconds. A latent image defined by the boundary between the polarity-switched and unswitched regions (corresponding to the exposed and unexposed regions, respectively) is thereby formed.

[0057] Next, the photoresist layer 106 is developed to remove the exposed areas of the layer, leaving the unexposed areas as shown. Figure 1BA resist pattern 106′ having a plurality of features is shown. The features are not limited to and may include, for example, a plurality of lines, pillars, and / or contact hole patterns that allow such patterns to be formed in the underlying layer to be patterned. The formed resist pattern has an initial size shown as L1, a line width of a line pattern, a pillar diameter of a pillar pattern, or a sidewall width of a contact hole pattern.

[0058] like Figure 1C As shown, a layer 112 of a photoresist pattern trimming composition as described herein is formed on the photoresist pattern 106'. The trimming composition is typically applied to the substrate by spin coating. The solids content of the coating solution can be adjusted to provide a desired film thickness based on the specific coating equipment used, the viscosity of the solution, the speed of the coating tool, and the amount of time allowed for spinning. The typical thickness of the pattern trimming composition layer 112 is typically 200 to 300 μm measured on an unpatterned substrate.

[0059] like Figure 1D As shown, next, the substrate is baked to remove the solvent in the trim composition layer. Baking also allows the acid of the trim composition to diffuse to the surface of the resist pattern 106' to cause a polarity change reaction in the resist pattern surface area 114. Baking can be performed with a hot plate or an oven, where a hot plate is typical. Suitable baking temperatures are greater than 50°C, such as greater than 70°C, greater than 90°C, greater than 120°C, or greater than 150°C, where a temperature of 70°C to 160°C and a time of about 30 to 90 seconds are typical. Although a single baking step is typical, multi-step baking can be used and can be used for resist profile adjustment.

[0060] Next, the photoresist pattern is contacted with a rinse agent (typically a developing solution) to remove the remaining trim composition layer 112 and typically also the surface regions 114 of the photoresist pattern, wherein the resulting pattern 106" is Figure 1E The rinse agent is typically an aqueous alkaline developer, such as an aqueous solution of quaternary ammonium hydroxide, for example, a tetraalkylammonium hydroxide solution, such as a tetramethylammonium hydroxide (TMAH) solution, typically 0.26 normal (N) (2.38 wt%) TMAH. In another aspect, the rinse agent can be water. The resulting structure is Figure 1E As shown in FIG. , the resist pattern after the trimming process has a smaller size ( L2 ) compared to the feature size before the trimming process.

[0061] Using the resist pattern 106" as an etching mask, the BARC layer 104 is selectively etched to form a BARC pattern 104' exposing the underlying hard mask layer 103, as shown in FIG. Figure 1FNext, the hard mask layer is selectively etched, again using the resist pattern as an etch mask, to produce a patterned BARC and hard mask layer 103′, as shown in FIG. Figure 1G As shown. Suitable etching techniques and chemicals for etching the BARC layer and the hard mask layer are known in the art and will depend, for example, on the specific materials of these layers. Dry etching processes such as reactive ion etching are typical. Next, the resist pattern 106″ and the patterned BARC layer 104′ are removed from the substrate using known techniques, such as oxygen plasma ashing. The one or more layers 102 are then selectively etched using the hard mask pattern 103′ as an etching mask. Suitable etching techniques and chemicals for etching the underlying layer 102 are known in the art, with dry etching processes such as reactive ion etching being typical. Next, the patterned hard mask layer 103′ can be removed from the substrate surface using known techniques, such as dry etching processes such as reactive ion etching or wet stripping. The resulting structure is a pattern of etched features 102′, such as Figure 1H In an alternative exemplary method, it may be desirable to directly pattern layer 102 using photoresist pattern 106″ without using hard mask layer 103. Whether direct patterning with a resist pattern can be used will depend on factors such as the materials involved, resist selectivity, resist pattern thickness, and pattern size.

[0062] The following non-limiting examples illustrate the invention.

[0063] Examples

[0064] Polymer synthesis

[0065] The polymers were synthesized using the following monomers according to the procedure described below:

[0066]

[0067] Polymer P1, Synthesis Example 1

[0068] Monomer feed solution is prepared by mixing 8.78g methyl isobutyl carbinol (MIBC) and 40.50g monomer M1 in the first container. Initiator feed solution is prepared by combining 1.91g Vazo-67 free radical initiator (DuPont (EIduPont de Nemours and Company)) and 17.20g MIBC in the second container and stirring the mixture to dissolve the initiator. 22.00g MIBC is introduced into the reaction vessel and the container is purged with nitrogen for 30 minutes. Next, the reaction vessel is heated to 90 ° C under agitation. Simultaneously, monomer feed solution and initiator feed solution are introduced into the reaction vessel. Feed monomer feed solution in the time period of 2 hours and feed initiator feed solution in the time period of 3 hours. The reaction vessel is maintained at 90 ° C for additional 7 hours under agitation, and then it is cooled to room temperature. The reaction mixture is precipitated from heptane (20x) to obtain polymer P1 (32g, 80% yield) in white solid. The weight average molecular weight (Mw) and number average molecular weight (Mn) are determined as polystyrene equivalent values ​​measured by gel permeation chromatography (GPC), and the polydispersity is calculated as PDI=Mw / Mn. The monomer ratios in the polymer and the molecular weight results are shown in Table 1.

[0069] Polymer P2, Synthesis Example 2

[0070] The monomer feed solution is prepared by dissolving 10.46g monomer M2, 5.16g monomer M3 and 5.63g monomer M5 in 190g ethyl lactate in a reaction vessel, and the solution is heated to 165°C. The initiator feed solution is prepared by combining 3.40g V-601 free radical initiator (Wako Chemical Company) and 34.50g ethyl lactate in a container and stirring the mixture to dissolve the initiator. The initiator feed solution is fed into the reaction vessel within a time period of 0.5 hours. The reaction vessel is maintained at 165°C for an additional 24 hours under stirring, and then cooled to room temperature. The reaction mixture is precipitated from methanol: water 75: 25 (wt%) (20x) to obtain a polymer P2 (17g, 81% yield) in a white solid. Mw, Mn and PDI are determined as described in Example 1. The monomer ratio and molecular weight results in the polymer are shown in Table 1.

[0071] Polymer P3, Synthesis Example 3

[0072] Monomer feed solution is prepared by dissolving 11.98g monomer M2, 1.90g monomer M4 and 5.13g monomer M5 in 108g ethyl lactate, and the solution is heated to 165°C. Initiator feed solution is prepared by combining 1.52g V-601 free radical initiator (Wako Chemical Co., Ltd.) and 70.00g ethyl lactate in a container and stirring the mixture to dissolve the initiator. In the time period of 0.5 hour, the initiator feed solution is fed into the reaction vessel. The reaction vessel is maintained at 165°C for an additional 24 hours under stirring, and then cooled to room temperature. The reaction mixture is precipitated from methanol: water 75 / 25 (wt%) (20x) to obtain a polymer P3 (15g, 79% yield) in white solid. Mw, Mn and PDI are determined as described in Example 1. The monomer ratio and molecular weight results in the polymer are shown in Table 1.

[0073] Polymer P4, Synthesis Example 4

[0074] Monomer feed solution is prepared by dissolving 11g monomer M2, 2.72g monomer M3 and 7.44g monomer M5 in 190g ethyl lactate in a reaction vessel, and the solution is heated to 165°C. Initiator feed solution is prepared by combining 3.40g V-601 free radical initiator (Wako Chemical Co., Ltd.) and 34.40g ethyl lactate in a container and stirring the mixture to dissolve the initiator. In the time period of 0.5 hour, the initiator feed solution is fed into the reaction vessel. The reaction vessel is maintained at 165°C for an additional 24 hours under stirring, and then cooled to room temperature. The reaction mixture is precipitated from methanol: water 75 / 25 (wt%) (20x) to obtain a polymer P4 (18g, 86%) in a white solid. The monomer ratio and molecular weight results in the polymer are shown in Table 1.

[0075] Polymer P5, Synthesis Example 5

[0076] Monomer feed solution is prepared by dissolving 12.93g monomer M2, 4.80g monomer M3 and 7.80g monomer M5 in 230g ethyl lactate in a reaction vessel, and the solution is heated to 165°C. Initiator feed solution is prepared by combining 4.00g V-601 free radical initiator (Wako Chemical Co., Ltd.) and 41.00g ethyl lactate in a container and stirring the mixture to dissolve the initiator. In the time period of 0.5 hour, the initiator feed solution is fed into the reaction vessel. The reaction vessel is maintained at 165°C for an additional 24 hours under stirring, and then cooled to room temperature. The reaction mixture is precipitated from methanol: water 75 / 25 (wt%) (20x) to obtain the polymer P5 (17.5g, 82% yield) in a white solid. The monomer ratio and molecular weight results in the polymer are shown in Table 1.

[0077] Table 1

[0078]

[0079] Acid synthesis

[0080] The following acids were used in the pattern modifying compositions as described below. Acids A1-A3 were synthesized according to the following procedure and the remaining acids were obtained commercially.

[0081]

[0082]

[0083] Acid A1, Synthesis Example 6

[0084] 25 g of 2,5-bis(trifluoromethyl)benzenesulfonyl chloride was dissolved in 15 g of water and refluxed for 24 h. After cooling, the reaction mixture was evaporated and dried under vacuum to give acid A1 as a white solid (20 g, 90% yield). 1 H NMR ((CD3)2CO, 600MHz): δ 8.04 (m, 1H), 8.08 (m, 1H), 8.50 (s, 1H), 9.52 (bs, 1H). 13 C NMR ((CD3)2CO, 600MHz): δ122.37, 123.71, 127.57, 127.59, 128.75, 130.48, 133.27, 144.70. 19 F NMR ((CD3)2CO, 600MHz): δ -63.93, -58.80].

[0085] Acid A2, Synthesis Example 7

[0086] Acid A2 was synthesized according to a procedure similar to that described for acid A1. Acid A2 was obtained as a white solid (19 g, 85.5% yield). 1 H NMR ((CD3)2CO, 600MHz): δ 8.15 (s, 1H), 8.34 (s, 2H), 10.81 (bs, 1H). 13 C NMR ((CD3)2CO, 600MHz): δ123.94, 124.22, 126.56, 131.51, 146.79. 19 F NMR ((CD3)2CO, 600MHz): δ-63.51].

[0087] Acid A3, Synthesis Example 8

[0088] Acid A3 was synthesized according to a procedure similar to that described for acid A1. Acid A3 was obtained as a white solid (18 g, 81% yield). 1 H NMR ((CD3)2CO, 600MHz): δ 7.61 (m, 1H), 7.71 (m, 1H), 8.33 (m, 1H), 10.83 (bs, 1H). 13 CNMR ((CD3)2CO, 600MHz): δ115.58, 115.71, 123.20, 131.20, 133.72, 136.86, 162.79, 164.46. 19 FNMR ((CD3)2CO, 600MHz): δ -98.75, -58.20].

[0089] Preparation of pattern modifying compositions

[0090] The photoresist pattern trimming composition (PTC) was prepared by dissolving the solid components in a solvent using the materials and amounts listed in Table 2. The resulting mixture prepared at a ratio of 14-30 g was shaken on a mechanical shaker for 3 to 24 hours and then filtered through a PTFE disk filter having a pore size of 0.2 micrometers.

[0091] Table 2

[0092]

[0093]

[0094] S1 = isoamyl ether; S2 = methyl isobutyl carbinol (MIBC); S3 = isobutyl isobutyrate; all amounts are provided in weight percent (wt %) based on the total pattern modifying composition.

[0095] Evaluation of Photoresist Pattern Modification Compositions

[0096] Critical dimension (CD) and line width roughness (LWR) evaluation

[0097] AR coating on 200mm silicon wafers on the TEL Clean TrackAct 8 coating tool TM 3 organic bottom anti-reflective coating (BARC) material (Dow Electronic Materials) and cured at 205°C for 60 seconds to On the TEL Clean Track Act 8 coating tool, apply UV TM 217G-0.25 polyhydroxystyrene based positive photoresist (Dow Electronic Materials) was coated on the BARC layer and the wafer was soft baked at 130°C for 60 seconds to The coated wafers were exposed to KrF (248 nm) radiation using a binary reticle with a 140 nm dense groove (1:1 line-space) pattern on a Canon FPA-5000 ES4 DUV scanner (NA=0.68, conventional illumination (σ, 0.75)). The wafers were post-exposure baked at 125°C for 60 seconds on a TEL Clean Track Act 8 coating tool, developed with 0.26N TMAH aqueous solution for 45 seconds, rinsed with distilled water and spin dried. Resist pattern CD and LWR measurements were performed using a Hitachi High Technologies Co. CG4000 CD-SEM to obtain initial CD and LWR values. Next, the wafers were coated with The corresponding pattern modification composition was baked at the temperature described in Table 3 for 60 seconds, rinsed with 0.26N TMAH aqueous solution for 30 seconds, rinsed with distilled water and spin dried. The CD and LWR measurements of the resist patterns of the treated wafers were then performed to obtain the final CD and LWR values. The CD change (ACD) of the treated pattern was calculated according to the following equation:

[0098] ΔCD=CD f -CD i

[0099] CD f is the average CD measurement after pattern trimming, and CD i The results are shown in Table 3.

[0100] Pattern Collapse Margin (PCM) Evaluation

[0101] AR coating on 200mm silicon wafers on TEL Clean Track Act 8 coating tool TM 3 organic bottom anti-reflective coating (BARC) material (DuPont) and cured at 205°C for 60 seconds to On the TELClean Track Act 8 coating tool, apply UV TM 217G-0.25 polyhydroxystyrene based positive photoresist (DuPont) was coated on the BARC layer and the wafer was soft baked at 130°C for 60 seconds to The coated wafers were exposed to 466 J / m on a Canon FPA-5000 ES4 DUV scanner (NA=0.68, conventional illumination (σ, 0.75)) using a binary reticle with a 140 nm dense groove (1:1 line-space) pattern. 2 Up to 626J / m 2 The wafers were post-exposure baked at 125°C for 60 seconds on a TEL Clean Track Act 8 coating tool, developed with 0.26N TMAH aqueous solution for 45 seconds, rinsed with distilled water and spin dried. Next, the wafers were coated with The corresponding pattern trimming composition was baked at the temperature described in Table 3 for 60 seconds, rinsed with 0.26N TMAH aqueous solution for 30 seconds, rinsed with distilled water and spin dried. The CD of the resist pattern of the treated wafer was then measured as described above. The SEM image of the pattern was observed to have pattern collapse. The CD of the largest non-collapsed groove (PCM) is reported in Table 3, and the larger the PCM value, the better the pattern collapse margin performance.

[0102] Table 3

[0103]

[0104]

[0105] *PCM not evaluated.

[0106] Coating defect assessment

[0107] The pattern trimming compositions were spin coated at 1500 rpm on corresponding 200 mm Si wafers. The coated wafers were baked at 80° C. for 60 seconds. The wafers were then inspected on a KLA-Tencor 2800 / Surfscan SP2 wafer surface inspection system. The system measures defects with a size greater than 45 nm. For each pattern trimming composition tested, two wafers were measured consecutively, and the lower of the two measured defect values ​​for each test composition is provided in Table 4.

[0108] Table 4

[0109]

[0110] * > 50K total defects are the upper limit of detection.

Claims

1. A photoresist pattern trimming composition comprising a polymer, an aromatic sulfonic acid and an organic solvent-based system, wherein the aromatic sulfonic acid has the general formula (II): in: R 1 independently represent a fluorine atom or a trifluoromethyl group, and one R 1 represents a trifluoromethyl group, and a represents an integer of 2 to 5.

2. The photoresist pattern trimming composition according to claim 1, wherein The polymer comprises repeating units formed from vinyl aromatic monomers.

3. The photoresist pattern trimming composition according to claim 1 or 2, wherein: The organic solvent based system comprises a monoether.

4. The photoresist pattern trimming composition according to claim 3, wherein: The organic-based solvent system further comprises an alcohol and / or an ester.

5. The photoresist pattern trimming composition according to any one of claims 1 to 4, wherein The composition is free of polymeric acid and polymeric acid generator.

6. The photoresist pattern trimming composition according to any one of claims 1 to 5, wherein The first R 1 represents trifluoromethyl, and the second R 1 represents a fluorine atom.

7. A pattern forming method, the method comprising: (a) providing a semiconductor substrate; (b) forming a photoresist pattern on the semiconductor substrate, wherein the photoresist pattern is formed from a photoresist composition comprising: a polymer comprising an acid-labile group; and a photoacid generator; (c) applying the pattern modifying composition according to any one of claims 1 to 5 on the photoresist pattern; (d) heating the coated photoresist pattern; as well as (e) rinsing the coated and heated photoresist pattern with a rinse agent to remove the residual pattern treatment composition.

8. The method of claim 7, wherein: The flushing agent is an aqueous solution of tetramethylammonium hydroxide.

9. The method according to claim 7 or 8, wherein: The photoresist pattern is formed by deep UV or EUV lithography.

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