Photoacid generator, photoresist composition, and pattern forming method

Abstract

To provide a photoacid generator, a photoresist composition and a pattern forming method.SOLUTION: There is provided a photoacid generator containing a portion of the formula (1): wherein, Ar1 is a substituted or unsubstituted aryl group; R1 is an alkyl or an aryl group, each of which may be substituted or unsubstituted, here, Ar1 and R1 are optionally connected to each other by a single bond or a divalent linking group to form a ring; Y is a single bond or a divalent group; * is a bonding point of a portion of the photoacid generator to another atom. This photoacid generator compound finds specific application in photoresist compositions which can be used to form lithographic patterns for the formation of electronic devices.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates generally to the manufacture of electronic devices. More specifically, the present invention relates to photoacid generators (PAGs), photoresist compositions containing PAGs, and patterning methods using the photoresist compositions. The PAGs, photoresist compositions, and patterning methods find particular use in the formation of lithographic patterns useful in the manufacture of semiconductor devices. [Background technology]

[0002] A photoresist composition is a photosensitive material used to transfer a pattern to one or more underlying layers, such as a metal, semiconductor, or dielectric layer, disposed on a substrate. Positive-tone, chemically amplified photoresist compositions are traditionally used for high-resolution processing. Such resist compositions typically contain a polymer with acid-labile groups and a photoacid generator (PAG). A layer of the photoresist composition is patternwise exposed to activating radiation, and the PAG generates acid in the exposed areas. During post-exposure baking, the acid causes cleavage of the acid-labile groups in the polymer. This creates a difference in solubility characteristics between the exposed and unexposed regions of the photoresist layer in a developer solution. In a positive-tone development (PTD) process, the exposed regions of the photoresist layer become soluble in a developer, typically an aqueous base developer, and are removed from the substrate surface. The unexposed regions, which are insoluble in the developer, remain after development to form a positive-tone relief image. The resulting relief image allows for selective processing of the substrate.

[0003] To increase the integration density of semiconductor devices and enable the formation of structures with dimensions in the nanometer (nm) range, photoresists and photolithography processing tools with high resolution capabilities have been developed and continue to be developed. One approach to achieving nm-scale features in semiconductor devices is to use activating radiation with short wavelengths, e.g., 193 nm or shorter, for exposure of photoresist layers. To further improve lithography performance, immersion lithography tools have been developed to effectively increase the numerical aperture (NA) of the lenses in the imaging device, such as immersion scanners with ArF (193 nm) light sources. This is achieved by using a fluid with a relatively high refractive index, typically water, between the final surface of the imaging device and the top surface of the semiconductor wafer.

[0004] ArF immersion tools are currently using multiple (double, triple, or higher) patterning techniques to push the limits of lithography processing up to the 16 nm and 14 nm device nodes. However, the use of multiple patterning can be costly in terms of increased material usage and the number of required process steps compared to single-step direct imaging patterns. The need for photoresist compositions for next-generation (e.g., EUV) lithography is therefore becoming increasingly important for advanced device nodes. With the extreme geometries associated with these nodes, the performance requirements for photoresist compositions are becoming increasingly more stringent. Desired performance characteristics include, for example, high sensitivity to activating radiation, low unexposed film thickness loss (UFTL), good contrast, high resolution capability, low surface roughness, good critical dimension uniformity (CDU), and minimal patterning defects.

[0005] Typical PAG compounds used in advanced photoresist compositions contain an anion, which is the conjugate base of the photogenerated acid, and an onium cation, which is hydrophobic. However, the hydrophobicity of the cation can result in insufficient dissolution of the exposed areas of the resist layer during aqueous base development. This can lead to patterning defects that can adversely affect device performance and product yield. The hydrophobic cation can also lead to instability of the latent image after exposure, which can adversely affect the profile of the resist pattern formed after development.

[0006] To address the developer PAG solubility issue, acid-labile groups can be included on the cation. Cleavage of the acid-labile groups in the exposed regions of the photoresist layer during post-exposure bake generates hydrophilic groups on the cation, thereby increasing solubility in aqueous base developers. The use of PAG cations containing acid-labile groups in photoresist compositions has been proposed. Patent Document 1, for example, discloses PAG cations containing acid-dissociable dissolution-inhibiting groups. Examples of such groups are disclosed as including cyclic or linear tertiary alkyl ester groups and acetal-type groups. Given current performance standards and chemistries for photoresists at advanced device nodes, providing new photoacid generators would be desirable. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US Patent Application Publication No. 2008 / 0248422 A1 Summary of the Invention [Problem to be solved by the invention]

[0008] There is a need in the art for photoacid generators, photoresist compositions, and patterning methods that address one or more problems associated with the state of the art. [Means for solving the problem]

[0009] According to a first aspect of the present invention, there is provided a photoacid generator comprising a moiety of formula (1): [ka] In the formula: Ar 1 is a substituted or unsubstituted aryl group; R 1 is an alkyl or aryl group, each of which may be substituted or unsubstituted, where Ar 1 and R 1 are optionally joined to each other by a single bond or a divalent linking group to form a ring; Y is a single bond or a divalent group; and * is the point of attachment of the moiety to another atom of the photoacid generator.

[0010] Also provided is a photoresist composition. The photoresist composition includes a photoacid generator and a solvent as described herein. The photoresist composition typically includes an acid-sensitive polymer. In such cases, the photoacid generator can be present as part of the polymerized units of the acid-sensitive polymer or as a component separate from the acid-sensitive polymer.

[0011] Also provided is a patterning method that includes the steps of: (a) forming a layer of photoresist from a photoresist composition as described herein on a substrate; (b) exposing the photoresist layer to activating radiation; and (c) developing the exposed photoresist layer to provide a resist relief image. DETAILED DESCRIPTION OF THE INVENTION

[0012] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms "a," "an," and "the" are intended to include both the singular and the plural unless the context dictates otherwise. All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. When an element is said to be "on" or "across" another element, it may be in direct contact with the other element, or intervening elements may be present between them. In contrast, when an element is said to be "directly on" another element, there are no intervening elements present.

[0013] The term "aromatic group" refers to a monocyclic or polycyclic ring system that satisfies Hückel's rule, and may be carbocyclic, containing only carbon atoms in the aromatic ring, or heterocyclic, containing one or more heteroatoms (e.g., N, O, or S) as ring atoms; "aryl group" refers to a monovalent aromatic group; and "arylene group" refers to an aromatic group having a valence of two.

[0014] The term "alkyl group" refers to a linear, branched, or cyclic saturated hydrocarbon group, or combinations thereof, having a valence of one; and "alkylene group" refers to an alkyl group having a valence of two.

[0015] The prefix "hetero" means that the compound or group contains one or more heteroatoms (e.g., 1, 2, 3, or 4 or more heteroatoms) in place of a respective carbon atom, where the heteroatoms can independently be, for example, N, O, S, Se, Te, Si, or P.

[0016] "Substituted" means that at least one hydrogen atom on a group has been replaced with another group, provided that the normal valence of the designated atom is not exceeded. Combinations of substituents or variables are permissible. Exemplary groups that may be present on a "substituted" position include nitro (-NO), cyano (-CN), hydroxy (-OH), amino (-NH), mono- or di-(C 1~6 ) alkylamino, alkanoyl (acyl, etc. C2~6 alkanoyl group, etc.), formyl (-C(=O)H), carboxylic acid or alkali metal salt or ammonium salt thereof, C 2~6 Alkyl esters (-C(=O)O-alkyl or -OC(=O)-alkyl) and C 7~13 Esters (including lactones), such as aryl esters (-C(=O)O-aryl or OC(=O)-aryl), amides (-C(=O)NR2, where R is hydrogen or C 1~6 alkyl), carboxamide (-CHC(=O)NR (where R is hydrogen or C 1~6 alkyl), halogen, thiol (-SH), C 1~6 Alkylthio (-S-alkyl), thiocyano (-SCN), C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 1~6 Haloalkyl, C 1~9 Alkoxy, C 1~6 Haloalkoxy, C 3~12 Cycloalkyl, C 5~18 Cycloalkenyl, C with at least one aromatic ring 6~12 Aryl (e.g., phenyl, biphenyl, naphthyl, etc., where each ring is either substituted or unsubstituted aromatic), C having 1 to 3 separate or fused rings and 6 to 18 ring carbon atoms 7~19 arylalkyl, arylalkoxy having 1 to 3 separate or fused rings and 6 to 18 ring carbon atoms, C 7~12 Alkylaryl, C 4~12 Heterocycloalkyl, C 3~12 Heteroaryl, C 1~6 Alkylsulfonyl (-S(=O)2-alkyl), C 6~12 Examples of alkyl groups include, but are not limited to, arylsulfonyl (-S(=O)-aryl), or tosyl (CHCHSO-), as well as vinyl and vinyl-containing groups such as acryl, vinyl ester, vinyl ketone, and norbornyl. If a group is substituted, the indicated number of carbon atoms is the total number of carbon atoms in the group, excluding carbon atoms of any substituents. For example, the group -CHCHCN is a C alkyl group substituted with a cyano group.

[0017] As used herein, "acid labile group" refers to a group that undergoes bond cleavage, optionally and typically with thermal treatment, by the catalytic action of an acid, resulting in the formation of a polar group, such as a carboxylic acid group or an alcohol group, formed on the polymer, and optionally and typically the moiety connected to the cleaved bond is cleaved from the polymer. Such acids are typically photogenerated acids, with bond cleavage occurring during post-exposure baking. Suitable acid labile groups include, for example, tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups with a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups, or ketal groups. Acid labile groups are also referred to in the art as "acid cleavable groups," "acid cleavable protecting groups," "acid labile protecting groups," "acid leaving groups," "acid decomposable groups," and "acid-sensitive groups."

[0018] Photoacid generator The photoacid generators (PAGs) of the present invention are photodecomposable upon exposure to activating radiation and generate an acid upon photolysis. The strength of the photogenerated acid of the PAG can vary widely, for example, having a pKa of -20 to 20, -15 to 15, -12 to 12, -15 to -1, or greater than -1 up to 6. The PAG comprises a moiety of formula (1): [ka] In the formula: Ar 1 is a substituted or unsubstituted aryl group, for example, C 6~40 Carbocyclic aryl or C 4~40 heterocyclic aryl, each of which may be monocyclic or polycyclic, substituted or unsubstituted, preferably substituted or unsubstituted C6 carbocyclic aryl; R 1 is a substituted or unsubstituted alkyl or aryl group, for example, C 1~20 Linear alkyl, C 3~20 Branched alkyl, monocyclic or polycyclic C 3~20 Cycloalkyl, monocyclic or polycyclic C 6~40 Carbocyclic aryl, or monocyclic or polycyclic C6~40 heterocyclic aryl, each of which may be substituted or unsubstituted, and preferably substituted or unsubstituted alkyl, where Ar 1 and R 1 are optionally joined to each other by a single bond or a divalent linking group to form a ring, exemplary linking groups include -O-, -S-, -Te-, -Se-, -C(O)-, -C(S)-, -C(Te)-, -S(O)-, -S(O)2-, -N(R)-, or -C(Se)-, substituted or unsubstituted C 1~5 alkylene, and combinations thereof, where R is hydrogen, C 1~20 Alkyl, C 1~20 Heteroalkyl, C 6~30 Carbocyclic aryl, or C 4~30 heterocyclic aryl, each of which, except for hydrogen, can be substituted or unsubstituted; Y is a single bond or a divalent group, such as -O-, -S-, -Te-, -Se-, -C(O)-, -C(O)O-, -N(R a )-, -C(O)N(R 2a )-, -N(R 2a )S(O)2-, substituted or unsubstituted C 1~30 Alkylene, substituted or unsubstituted C 3~30 Cycloalkylene, substituted or unsubstituted C 1~30 Heterocycloalkylene, substituted or unsubstituted C 6~30 Arylene, substituted or unsubstituted C 7~30 Aryl alkylene, substituted or unsubstituted C 1~30 Heteroarylene, substituted or unsubstituted C 3~30 heteroarylalkylene, where R a and R 2a are independently hydrogen, C 1~20 Alkyl, C 1~20 Heteroalkyl, C 6~30 Aryl or C 4~30heteroaryl, or combinations thereof, each of which, except for hydrogen, can be substituted or unsubstituted, and optionally further comprises one or more of -S(O)-, -S(O)2-, -C(S)-, -C(Te)-, or -C(Se)-, with -CH2C(O)O- being preferred for Y; * is the point of attachment of the moiety to another atom of the photoacid generator. The moiety of formula (1) comprises an acid-labile secondary ester group. Upon photogenerated acid, the O-C bond of the secondary ester is cleaved, leaving a carboxylic acid group on the degraded PAG.

[0019] The photoacid generator having the moiety of formula (1) is not particularly limited and can be ionic or non-ionic. Preferably, the PAG is ionic and is represented by formula (2): G + Z - (2) In the formula, G + is a cation containing a moiety of formula (1), and Z - is a counter anion, which may be referred to herein as the cation moiety and the anion moiety, respectively. The cation and anion are typically organic. The acid strength of the photogenerated acid is determined by the anion moiety.

[0020] The ionic PAG can be selected from onium salts such as sulfonium salts, iodonium salts, halonium salts, quaternary ammonium salts, phosphonium salts, arsonium salts, sulfoxonium salts, tellurium salts, or selenium salts. Preferably, the PAG is a sulfonium or iodonium salt. The acid generator group may include, for example, a negatively charged aromatic sulfonate or perfluoroalkyl sulfonate and a substituted triarylsulfonium or substituted diaryliodonium countercation. A preferred such ionic PAG is represented by formula (2-1): [ka] In the formula: Ar 1 , R 1 and Y are each independently as defined above with respect to formula (1); Ar 2are independently a substituted or unsubstituted arylene group, for example, C 6~40 Carbocyclic aryl or C 4~40 heterocyclic aryl, each of which is monocyclic or polycyclic, substituted or unsubstituted, preferably a substituted or unsubstituted C6 carbocyclic aryl group; X is S or I; R 2 are independently substituted or unsubstituted alkyl or aryl groups, e.g., C 1~20 Linear alkyl, C 3~20 Branched alkyl, monocyclic or polycyclic C 3~20 Cycloalkyl, monocyclic or polycyclic C 6~40 Carbocyclic aryl, or monocyclic or polycyclic C 4~40 heterocyclic aryl, each of which is substituted or unsubstituted, preferably a C6 carbocyclic aryl group; Z - is the counter anion; a ranges from 1 to Ar 2 up to the total number of available carbon atoms, typically 1 to 5, more typically 1 or 2; when X is S, b is 1, 2, or 3 and c is 3; when X is I, b is 1 or 2 and c is 2; where (i) two R 2 or (ii) one Ar 2 group and one R 2 The groups are optionally joined to each other by a single bond or a divalent linking group to form a ring. Exemplary divalent linking groups include -O-, -S-, -Te-, -Se-, -C(O)-, -C(S)-, -C(Te)-, -S(O)-, -S(O)2-, -N(R)-, or -C(Se)-, substituted or unsubstituted C 1~5 alkylene, and combinations thereof, where R is hydrogen, C 1~20 Alkyl, C 1~20 Heteroalkyl, C 6~30 Carbocyclic aryl, or C 4~30 Heterocyclic aryl, each of which, except for hydrogen, can be substituted or unsubstituted. 2 group or one Ar 2 group and one R 2When groups are bonded to each other to form a ring, it is preferably a single bond, -O-, -S-, or -C(O)-.

[0021] Suitable exemplary PAG cations of formula (2-1) include: [ka] [ka] [ka] [ka]

[0022] The selection of a suitable PAG anion will depend, for example, on the desired pKa of the photogenerated acid. Preferred PAG anions include groups selected from sulfonate anions, methide anions, sulfonamide anions, sulfonimide anions, sulfamate anions, phenolate anions, or carboxylate anions. Suitable exemplary PAG anions that can be paired with the cations described above include the following: [ka] [ka]

[0023] Suitable nonionic PAGs include, for example, nitrobenzyl derivatives, diazomethane derivatives, sulfonate ester derivatives, glyoxime derivatives, β-ketosulfone derivatives, disulfone derivatives, nitrobenzyl sulfonate derivatives, imido-yl sulfonate derivatives, oxime sulfonate derivatives, iminosulfonate derivatives, and triazine derivatives that contain the moiety of formula (1) as described above.

[0024] Suitable exemplary non-ionic PAGs include, for example: [ka] [ka]

[0025] PAGs can be in the form of non-polymeric compounds or polymers. Suitable non-polymeric compounds include monomers and non-polymerizable compounds. Typical monomers contain a free-radically polymerizable group, such as a vinyl group, and styrene, acrylic, vinyl ether, vinyl ketone, and norbornyl monomers are typical.

[0026] In some embodiments, an ionic or nonionic PAG may optionally be covalently attached to the polymer as a pendant group at the polymerized units of the polymer. In the case of an ionic PAG, an anion or cation may be covalently attached to the polymer. For example, in Formula (2-1), the sulfonium or iodonium salt of Formula (1) may optionally have a cationic moiety, Ar 1 , R 1 , or R 2 The anion portion of the sulfonium or iodonium salt of formula (1) may be covalently attached to the polymer as a pendant group via the above substituents, or Z - For example, the pendant group may be attached to the main chain or backbone of the polymer.

[0027] The polymerized units that comprise the PAG can be derived, for example, from the following exemplary monomers: [ka] (In the formula, G + and Z - is as defined above).

[0028] The polymer may be a homopolymer or, more typically, a copolymer comprising one or more additional repeat units different from the repeat unit comprising the PAG. Suitable additional repeat units can include, for example, one or more additional units such as those described below with respect to the acid-sensitive polymer of the photoresist composition. When used in a copolymer, the repeat unit comprising the PAG is typically present in an amount of 1 to 90 mol %, 1 to 40 mol %, more typically 1 to 25 mol %, and even more typically 2 to 15 mol %, based on the total repeat units in the polymer.

[0029] The polymers typically have an M of 1500 to 50,000 Da, 2000 to 30,000 Da, more particularly 3000 to 20,000 Da, and even more particularly 3000 to 10,000 Da. w M n M against w The PDI of a polymer, which is the ratio of PDI to PDI, is typically 1.1 to 5, more typically 1.3 to 2.5. Molecular weights are determined by GPC using polystyrene standards.

[0030] The photoacid generators of the present invention can be prepared by one skilled in the art. For example, PAGs can be synthesized by covalent attachment of the moiety of formula (1) to an onium salt cation or to a non-ionic PAG. Covalent attachment can be achieved, for example, by an alkylation or esterification reaction between a hydroxy-substituted cation of the onium salt or non-ionic PAG and a derivative of the moiety of formula (1). An exemplary alkylation reaction is the reaction of a hydroxy-substituted onium salt or a hydroxy-substituted non-ionic photoacid generator with Hal-YC(=O)-O-CH(R 1 )Ar 1 where Y, R 1 and Ar 1 is as defined above with respect to formula (1). In the case of an onium salt, the product of the alkylation step is typically an onium halide, which is then reacted with an onium halide of formula Z - X + (In the formula, Z -is as defined above, and X + is an inorganic or organic counter cation) to produce a photoacid generator of formula (2-1).

[0031] Photoresist composition The photoacid generators described herein can be used for a variety of applications, and are particularly useful in photoresist compositions useful in the manufacture of electronic devices, such as semiconductor devices, circuit boards, and display devices. The photoresist composition includes a photoacid generator and a solvent, as described above, and may include one or more additional optional components. The PAG can perform various functions in the composition, depending on the strength of the acid generated and the other components of the photoresist composition. For example, in one embodiment, the PAG can function as a source of acid to deprotect acid-labile groups on the PAG and / or on a separate acid-sensitive polymer. In another embodiment, the PAG can function as a photolytic quencher (PDQ) when used in combination with a second PAG, where the corresponding photoacid of the second PAG has a lower pKa than the corresponding photoacid of the PDQ.

[0032] Given the acid-sensitive nature of the PAGs of the present invention, the PAG itself, whether in polymeric or non-polymeric form, can function as a photoresist matrix in one embodiment of the present invention. Therefore, the photoresist composition can optionally be free of an acid-sensitive polymer that is chemically distinct from the PAG. Alternatively, and more typically, the photoresist composition can include an acid-sensitive polymer that is chemically distinct from the PAG. Thus, the PAGs of the present invention can be present in the photoresist composition in a wide range of amounts, for example, from 1 to 100% by weight, based on the total solids content of the photoresist composition. When an acid-sensitive polymer that is chemically distinct from the PAG is used, the PAG is typically present in an amount of from 1 to 65% by weight, more typically from 5 to 55% by weight, and even more typically from 8 to 30% by weight, based on the total solids content of the photoresist composition. When the PAG, whether in polymeric or non-polymeric form, functions as the sole or primary acid-sensitive component of the photoresist composition, the PAG is typically present in an amount of 50 to 100 wt %, more typically 90 to 100 wt %, and even more typically 95 to 99.5 wt %, based on the total solids content of the photoresist composition.

[0033] The photoresist composition can include one or more acid-sensitive polymers. The acid-sensitive polymers include polymerized units that include acid-labile groups, such as tertiary ester or acetal groups. Additionally or alternatively, the polymerized units that include acid-labile groups can be derived from PAG monomers of the present invention. Other suitable monomers for these polymerized units include, for example: [ka] [ka] (In the formula, R d are hydrogen, fluorine, C 1~5 Alkyl, or C 1~5 fluoroalkyl, typically hydrogen or methyl).

[0034] The repeat units having an acid labile group are typically present in the acid-sensitive polymer in an amount of from 10 to 80 mol %, more typically from 25 to 75 mol %, and even more typically from 30 to 70 mol %, based on the total repeat units in the acid-sensitive polymer.

[0035] In some embodiments, the acid-sensitive polymer may include repeat units having an aromatic group, where the aromatic group may be substituted or unsubstituted. The aromatic group may be a monocyclic or polycyclic C 1 -C 2 -C 3 -C 4 -C 5 -C 6 -C 7 -C 8 -C 9 -C 10 -C 11 -C 12 -C 13 -C 14 -C 15 -C 16 -C 17 -C 18 -C 19 -C 20 -C 21 -C 22 -C 23 -C 24 -C 25 -C 26 -C 27 -C 28 -C 29 -C 30 -C 31 -C 32 -C 33 -C 40 -C 41 -C 22 -C 34 -C 42 -C 23 -C 44 -C 24 -C 25 -C 26 -C 27 -C 28 -C 29 -C 30 -C 31 -C 29 -C 32 -C 33 -C 44 -C 29 -C 34 -C 45 -C 26 -C 27 -C 28 -C 35 -C 29 -C 36 -C 37 -C 38 -C 40 -C 29 -C 39 -C 40 -C 41 -C 29 -C 29 -C 30 -C 42 -C 29 -C 30 -C 43 -C 44 -C 29 -C 35 -C 45 -C 29 -C 36 -C 46 -C 29 -C 37 -C 47 -C 48 -C 49 -C 50 -C 51 -C 52 -C 53 -C 54 -C 55 -C 56 -C 57 -C 58 5~60 When the aromatic group is polycyclic, the rings or ring groups may be fused (such as naphthyl), directly linked (such as biaryls, such as biphenyl), bridged by heteroatoms (such as triphenylamino or diphenylene ether), and / or contain a combination of fused and directly linked rings (such as binaphthyl).

[0036] Monocyclic or polycyclic C 5~60 The aromatic group can be substituted or unsubstituted. Exemplary substituents include substituted or unsubstituted C 1~30 Alkyl, substituted or unsubstituted C 1~30 Haloalkyl, substituted or unsubstituted C 3~30 Cycloalkyl, substituted or unsubstituted C 1~30 Heterocycloalkyl, substituted or unsubstituted C 2~30 Alkenyl, substituted or unsubstituted C 2~30 Alkynyl, substituted or unsubstituted C 6~30 Aryl, substituted or unsubstituted C 7~30 Aryl alkyl, substituted or unsubstituted C 7~30 Alkylaryl, substituted or unsubstituted C 3~30 Heteroaryl, substituted or unsubstituted C 4~30 Heteroarylalkyl, halogen, -OR 51 , -SR 52 , or -NR 53 R 54 These include, but are not limited to, where R51 ~R 54 are each independently hydrogen or a substituted or unsubstituted C 1~30 Alkyl, substituted or unsubstituted C 3~30 Cycloalkyl, substituted or unsubstituted C 2~30 Heterocycloalkyl, substituted or unsubstituted C 6~30 Aryl, substituted or unsubstituted C 7~30 Aryl alkyl, substituted or unsubstituted C 3~30 Heteroaryl, or substituted or unsubstituted C 4~30 Preferably, the aromatic group is a substituted C 6~30 Aryl group or substituted C 7~30 heteroaryl groups, where the aromatic group is -OR 51 , -SR 52 , or -NR 53 R 54 and the like, where R 51 ~R 54 are each independently hydrogen or a substituted or unsubstituted C 1~10 Alkyl, substituted or unsubstituted C 3~20 Cycloalkyl, substituted or unsubstituted C 2~20 Heterocycloalkyl, substituted or unsubstituted C 6~30 Aryl, substituted or unsubstituted C 7~30 Aryl alkyl, substituted or unsubstituted C 3~30 Heteroaryl, or substituted or unsubstituted C 4~30 It is heteroarylalkyl.

[0037] The repeat units having an aromatic group are typically present in the acid-sensitive polymer in an amount of 5 to 80 mol %, more typically 10 to 50 mol %, and even more typically 10 to 40 mol %, based on the total repeat units in the acid-sensitive polymer.

[0038] The acid-sensitive polymer may comprise a repeat unit comprising a lactone group. Suitable repeat units may be derived, for example, from monomers of formula (5a) or formula (5b): [ka]

[0039] In formula (5a), R is hydrogen, fluorine, cyano, substituted or unsubstituted C 1~10 Alkyl, or substituted or unsubstituted C 1~10 Preferably, R d is hydrogen, fluorine, or substituted or unsubstituted C 1~5 It is alkyl, typically methyl. 3 is a single bond or a substituted or unsubstituted C 1~30 Alkylene, substituted or unsubstituted C 1~30 Heteroalkylene, substituted or unsubstituted C 3~30 Cycloalkylene, substituted or unsubstituted C 1~30 Heterocycloalkylene, substituted or unsubstituted C 6~30 Arylene, substituted or unsubstituted C 7~30 Aryl alkylene, or substituted or unsubstituted C 1~30 Heteroarylene, or substituted or unsubstituted C 3~30 and a divalent linking group comprising one or more of: heteroarylalkylene; 3 is optionally exemplified by, for example, -O-, -C(O)-, -C(O)-O-, -S-, -S(O)2-, and -N(R 44 )—S(O)—, where R 44 is hydrogen, linear or branched C 1~20 Alkyl, monocyclic or polycyclic C 3~20 Cycloalkyl, or monocyclic or polycyclic C 3~20 R may be heterocycloalkyl. 14 is a monocyclic, polycyclic, or fused polycyclic C 4~20 In formula (5b), R 15 is a hydrogen or non-hydrogen substituent, typically a substituted or unsubstituted C 1~10 alkyl, and n is 1 or 2.

[0040] Suitable exemplary lactone-containing monomers of formula (5a) and (5b) include: [ka] where R is as defined above. When present, the acid-sensitive polymer typically comprises lactone repeat units in an amount of 5 to 60 mol %, typically 20 to 55 mol %, more typically 25 to 50 mol %, based on the total repeat units in the acid-sensitive polymer.

[0041] The acid-sensitive polymer may comprise a base-soluble repeat unit having a pKa of less than or equal to 12. For example, the base-soluble repeat unit may be derived from a monomer of formula (6): [ka]

[0042] In equation (6), R g is hydrogen, fluorine, cyano, substituted or unsubstituted C 1~10 Alkyl, or substituted or unsubstituted C 1~10 Preferably, R g is hydrogen, fluorine, or substituted or unsubstituted C 1~5 Q is an alkyl group, typically methyl. 4 is a substituted or unsubstituted C 1~30 Alkylene, substituted or unsubstituted C 3~30 Cycloalkylene, substituted or unsubstituted C 1~30 Heterocycloalkylene, substituted or unsubstituted C 6~30 Arylene, substituted or unsubstituted divalent C 7~30 Aryl alkyl, substituted or unsubstituted C 1~30 Heteroarylene or substituted or unsubstituted divalent C 3~30 W may contain one or more of the following: heteroarylalkyl, -C(O)-O-; W is a base-solubilizing group, for example, hydroxyl (OH); -C(O)-OH; fluorinated alcohols such as -C(CF)OH; imide; or -NH-S(O)-Y. 1 (where Y 1 is C 1~4alkyl or fluoroalkyl, typically C 1~4 In formula (6), a is an integer of 1 to 3.

[0043] Non-limiting examples of monomers of formula (6) include: [ka] (In the formula, R g is as described above). When present, the acid-sensitive polymer typically comprises the above-described base-soluble repeat units in an amount of 5 to 60 mol %, typically 20 to 55 mol %, more typically 25 to 50 mol %, based on the total repeat units in the acid-sensitive polymer.

[0044] The acid-sensitive polymer may optionally contain one or more additional repeating units. The additional repeating structural units may include one or more additional units for the purpose of adjusting the properties of the photoresist composition, such as, for example, the etch rate and solubility. The additional units may include, for example, one or more styrene, (meth)acrylate, vinyl ether, vinyl ketone, or vinyl ester type units. When present in the acid-sensitive polymer, the one or more additional repeating units may be used in an amount of up to 70 mol %, typically 3 to 50 mol %, based on the total repeating units of the acid-sensitive polymer.

[0045] Non-limiting examples of acid-sensitive polymers include: [ka] [ka] [ka] (wherein a, b, c and d represent the mole fraction of the corresponding repeating unit).

[0046] The acid-sensitive polymer typically has a weight-average molecular weight (Mw) of 1,000 to 50,000 Daltons (Da), particularly 2,000 to 30,000 Da, more particularly 3,000 to 20,000 Da, and even more particularly 3,000 to 10,000 Da. The polydispersity index (PDI) of the acid-sensitive polymer, which is the ratio of Mw to number-average molecular weight (Mn), is typically 1.1 to 3, particularly 1.1 to 2. Molecular weight values ​​are determined by gel permeation chromatography (GPC) using polystyrene standards.

[0047] The acid-sensitive polymer and any other polymer in the photoresist composition can be prepared by any suitable method known in the art.For example, one or more monomers corresponding to the repeating units of the polymer can be combined with a suitable solvent and an initiator or supplied separately, and polymerized in a reactor.The polymer can be obtained by polymerization under any suitable conditions, such as heating at an effective temperature, irradiating with actinic rays at an effective wavelength, or a combination thereof.

[0048] The photoresist composition may further include a basic quencher and / or a photodegradable quencher (PDQ) (also known as a photodegradable base), each of which, when used, is typically present in an amount of 0.01 to 10 wt % based on the total solids content of the photoresist composition.

[0049] Exemplary basic quenching agents include, for example, linear aliphatic amines such as tributylamine, trioctylamine, triisopropanolamine, tetrakis(2-hydroxypropyl)ethylenediamine; n-tert-butyldiethanolamine; tris(2-acetoxyethyl)amine; 2,2′,2″,2′′-(ethane-1,2-diylbis(azanetriyl))tetraethanol; 2-(dibutylamino)ethanol; and 2,2′,2″-nitrilotriethanol; cyclic aliphatic amines such as 1-(tert-butoxycarbonyl)-4-hydroxypiperidine, tert-butyl 1-pyrrolidinecarboxylate, tert-butyl 2-ethyl-1H-imidazole-1-carboxylate, di-tert-butyl piperazine-1,4-dicarboxylate, and N-(2-acetoxyethyl)morpholine; pyridine, di-tert-butylpyridine, and pyridine. linear and cyclic amides and derivatives thereof, such as N,N-bis(2-hydroxyethyl)pivalamide, N,N-diethylacetamide, N1,N1,N3,N3-tetrabutylmalonamide, 1-methylazepan-2-one, 1-allylazepan-2-one, and tert-butyl 1,3-dihydroxy-2-(hydroxymethyl)propan-2-ylcarbamate; ammonium salts, such as quaternary ammonium salts of sulfonates, sulfamates, carboxylates, and phosphonates; imines, such as primary and secondary aldimines and ketimines; optionally substituted diazines, such as pyrazine, piperazine, and phenazine; optionally substituted diazoles, such as pyrazole, thiadiazole, and imidazole; and optionally substituted pyrrolidones and cyclohexylpyrrolidines, such as 2-pyrrolidone.

[0050] The photolytic quencher PDQ generates, upon irradiation, a relatively weak acid that does not rapidly react with acid-labile groups in the photoresist composition. Exemplary photolytic quenchers, which are also useful for preparing photolytic cations, and preferably strong acid generators, include, for example, C 1~20 Weak acids such as carboxylic acids or C 1~20Examples of suitable carboxylic acids include those paired with sulfonic acid anions. Exemplary carboxylic acids include formic acid, acetic acid, propionic acid, tartaric acid, succinic acid, cyclohexanecarboxylic acid, benzoic acid, salicylic acid, etc. Exemplary carboxylic acids include p-toluenesulfonic acid, camphorsulfonic acid, etc. In a preferred embodiment, the photolytic quencher is a photolytic organic zwitterionic compound such as diphenyliodonium-2-carboxylate.

[0051] The photoresist composition may contain one or more photoacid generators in addition to the PAG of the present invention. Such additional PAGs are typically non-polymeric, but may also be in polymeric form, for example, present in the polymerized repeat units of the acid-sensitive polymer or as part of a different polymer. Suitable PAG compounds include, for example, onium salts such as triphenylsulfonium trifluoromethanesulfonate, (p-tert-butoxyphenyl)diphenylsulfonium trifluoromethanesulfonate, tris(p-tert-butoxyphenyl)sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate; di-t-butylphenyliodonium perfluorobutanesulfonate, and di-t-butylphenyliodonium camphorsulfonate. Nonionic sulfonate and sulfonyl compounds are also known to function as photoacid generators, such as nitrobenzyl derivatives, e.g., 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate, and 2,4-dinitrobenzyl-p-toluenesulfonate; sulfonic acid esters, e.g., 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene; diazomethane derivatives, e.g., bis(benzenesulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, and bis(p-toluenesulfonyl)diazomethane. glyoxime derivatives such as bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime; sulfonate derivatives of N-hydroxyimide compounds such as N-hydroxysuccinimide methanesulfonate and N-hydroxysuccinimide trifluoromethanesulfonate; and halogen-containing triazine compounds such as 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine and 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-triazine.Other suitable sulfonate PAGs include sulfonated esters and sulfonyloxyketones, nitrobenzyl esters, s-triazine derivatives, benzoin tosylate, t-butylphenyl α-(p-toluenesulfonyloxy)acetate, and t-butyl α-(p-toluenesulfonyloxy)acetate. Of these, onium salts such as sulfonium or iodonium salts are typical. When present, such additional PAGs are present in an amount of 1 to 65 wt %, more typically 5 to 55 wt %, and even more typically 8 to 30 wt %, based on the total solids content of the photoresist composition.

[0052] The photoresist composition may further comprise a material containing one or more base-labile groups ("base-labile material"). As referred to herein, a base-labile group is a functional group that can undergo a cleavage reaction in the presence of an aqueous alkaline developer after the exposure and post-exposure bake steps to provide a polar group such as a hydroxyl, carboxylic acid, sulfonic acid, or the like. The base-labile group will not significantly react (e.g., will not undergo a bond-breaking reaction) before the development step of a photoresist composition containing the base-labile group. Thus, for example, the base-labile group will be substantially inert during the pre-exposure soft bake, exposure, and post-exposure bake steps. "Substantially inert" means that 5% or less, preferably 1% or less, of the base-labile groups (or moieties) will decompose, cleave, or react during the pre-exposure soft bake, exposure, and post-exposure bake steps. The base-labile group is reactive under typical photoresist development conditions, for example, using an aqueous alkaline photoresist developer such as an aqueous solution of 0.26N tetramethylammonium hydroxide (TMAH). For example, a 0.26N aqueous solution of TMAH can be used to develop the resist pattern using a single puddle development or dynamic development process, where the 0.26N TMAH developer is dispensed onto the imaged photoresist layer for a suitable time, such as 10 to 120 seconds. An exemplary base-labile group is an ester group, typically a fluorinated ester group. Preferably, the base-labile material is substantially immiscible with the other solid components of the photoresist composition and has a lower surface energy than the other solid components. When coated onto a substrate, the base-labile material can thereby separate from the other solid components of the photoresist composition to the top surface of the formed photoresist layer.

[0053] The base-labile material is preferably a polymeric material, also referred to herein as a base-labile polymer, which may include one or more repeat units containing one or more base-labile groups. For example, the base-labile polymer may include repeat units containing two or more base-labile groups, which may be the same or different. Preferred base-labile polymers include at least one repeat unit containing two or more base-labile groups, for example, repeat units containing two or three base-labile groups.

[0054] The base-labile polymer may be a polymer comprising repeat units derived from monomers of formula (E1). [ka] (In the formula, X b is a polymerizable group selected from vinyl and acrylic; L 5 is a substituted or unsubstituted linear or branched C 1~20 Alkylene, substituted or unsubstituted C 3~20 a divalent linking group containing one or more of cycloalkylene, —C(O)—, or —C(O)O—; R k is a substituted or unsubstituted C 1~20 a fluoroalkyl group, provided that the carbon atom bonded to the carbonyl (C=O) in formula (E1) is substituted with at least one fluorine atom).

[0055] Exemplary monomers of formula (E1) include: [ka]

[0056] The base-labile polymer may comprise repeat units comprising two or more base-labile groups. For example, the base-labile polymer may comprise repeat units derived from monomers of formula (E2). [ka] (In the formula, X b and R kis as defined in formula (E1); L 6 is a substituted or unsubstituted straight-chain or branched C 1~20 Alkylene, substituted or unsubstituted C 3~20 is a polyvalent linking group that includes one or more of cycloalkylene, —C(O)—, or —C(O)O—; and n is an integer of 2 or greater, for example, 2 or 3.

[0057] Exemplary monomers of formula (E2) include: [ka]

[0058] The base-labile polymer may comprise repeat units comprising one or more base-labile groups. For example, the base-labile polymer may comprise repeat units derived from monomers of formula (E3): [ka] In the formula, X b is as defined in formula (E1); L 7 is a substituted or unsubstituted straight-chain or branched C 1~20 Alkylene, substituted or unsubstituted C 3~20 a divalent linking group containing one or more of cycloalkylene, —C(O)—, or —C(O)O—; L f is a substituted or unsubstituted C 1~20 a fluoroalkylene group, wherein the carbon atom bonded to the carbonyl (C═O) in formula (E1) is substituted with at least one fluorine atom; R m is a substituted or unsubstituted straight-chain or branched C 1~20 Alkyl, or substituted or unsubstituted C 3~20 It is cycloalkyl.

[0059] Exemplary monomers of formula (E3) include: [ka]

[0060] In a further preferred embodiment of the present invention, the base-labile polymer may contain one or more base-labile groups and one or more acid-labile groups, such as one or more acid-labile ester moieties (e.g., t-butyl esters) or acid-labile acetal groups. For example, the base-labile polymer may contain a repeating unit containing a base-labile group and an acid-labile group, i.e., a repeating unit in which both the base-labile group and the acid-labile group are present on the same repeating unit. In another example, the base-labile polymer may contain a first repeating unit containing a base-labile group and a second repeating unit containing an acid-labile group. Preferred photoresists of the present invention can exhibit reduced defects associated with resist relief images formed from the photoresist composition. When present, the content of the base-labile polymer is typically 0.01 to 10 wt %, based on the total solids content of the photoresist composition.

[0061] The base-labile polymer can be prepared using any suitable method in the art, including those described herein for the first and second polymers. For example, the base-labile polymer can be obtained by polymerization of the respective monomers under any suitable conditions, such as heating at an effective temperature, irradiating with actinic radiation at an effective wavelength, or a combination thereof. Additionally or alternatively, one or more base-labile groups can be grafted onto the backbone of the polymer using a suitable method.

[0062] The photoresist composition may further comprise one or more additional optional additives. For example, optional additives may include chemical dyes and contrast agents, anti-streak agents, plasticizers, rate enhancers, sensitizers, surfactants, etc., or combinations thereof. When present, the content of each optional additive is typically 0.01 to 10 wt % based on the total solids content of the photoresist composition.

[0063] Exemplary surfactants include fluorinated and non-fluorinated surfactants and can be ionic or non-ionic, with non-ionic surfactants being preferred. Exemplary fluorinated non-ionic surfactants include perfluoro C4 surfactants such as FC-4430 and FC-4432 surfactants (3M Corporation); and fluorodiols such as POLYFOX PF-636, PF-6320, PF-656, and PF-6520 fluorosurfactants (Omnova).

[0064] The photoresist composition further comprises a solvent for dissolving the components of the composition and facilitating its coating on a substrate. Preferably, the solvent is an organic solvent conventionally used in the manufacture of electronic devices. Suitable solvents include, for example: aliphatic hydrocarbons such as hexane and heptane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane, and 1-chlorohexane; alcohols such as methanol, ethanol, 1-propanol, isopropanol, tert-butanol, 2-methyl-2-butanol, 4-methyl-2-pentanol, and diacetone alcohol (4-hydroxy-4-methyl-2-pentanone); propylene glycol monomethyl ether (PGME); ethers such as diethyl ether, tetrahydrofuran, 1,4-dioxane, and anisole; and solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone (CHO). Examples of suitable solvents include ketones, esters such as ethyl acetate, n-butyl acetate, propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL), hydroxyisobutyric acid methyl ester (HBM), and ethyl acetoacetate, lactones such as gamma-butyrolactone (GBL) and epsilon-caprolactone, lactams such as N-methylpyrrolidone, nitriles such as acetonitrile and propionitrile, cyclic or acyclic carbonate esters such as propylene carbonate, dimethyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and propylene carbonate, polar aprotic solvents such as dimethyl sulfoxide and dimethylformamide, water, and combinations thereof. Among these, preferred solvents are PGME, PGMEA, EL, GBL, HBM, CHO, and combinations thereof. The total solvent content (i.e., the cumulative solvent content of all solvents) in a photoresist composition is typically 40 to 99 wt %, for example, 70 to 99 wt %, or 85 to 99 wt %, based on the total solids content of the photoresist composition. The desired solvent content will depend, for example, on the desired thickness of the coated photoresist layer and the coating conditions.

[0065] Photoresist compositions can be prepared according to known procedures. For example, the composition can be prepared by dissolving the solid components of the photoresist composition in a solvent. The photoresist composition or one or more components of the composition can optionally be subjected to one or more purification processes, such as filtration and / or ion exchange processes. The desired total solids content of the composition will depend on factors such as the desired final layer thickness. The solids content of the photoresist composition is typically 1 to 10 wt %, more preferably 1 to 5 wt %, based on the total weight of the composition.

[0066] Pattern Formation Method A patterning method using the photoresist composition of the present invention is described below. Suitable substrates onto which the photoresist composition can be coated include electronic device substrates. A wide variety of electronic device substrates can be used in the present invention, including semiconductor wafers, polycrystalline silicon substrates, packaging substrates such as multichip modules, flat panel display substrates, and substrates for light-emitting diodes (LEDs) such as organic light-emitting diodes (OLEDs), with semiconductor wafers being typical. Such substrates are typically composed of one or more of silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon germanium, gallium arsenide, aluminum, sapphire, tungsten, titanium, titanium-tungsten, nickel, copper, and gold. Suitable substrates may be in the form of wafers, such as those used in the manufacture of integrated circuits, optical sensors, flat panel displays, optical integrated circuits, and LEDs. Such substrates may be of any suitable size. Typical wafer substrate diameters are 200 to 300 millimeters (mm), although wafers with smaller and larger diameters may be suitably used in accordance with the present invention. The substrate may include one or more layers or structures that may optionally include working or operable portions of the device being formed.

[0067] Typically, one or more lithographic layers, such as a hard mask layer, e.g., a spin-on carbon (SOC), amorphous carbon, or metal hard mask layer, a CVD layer such as a silicon nitride (SiN), silicon oxide (SiO), or silicon oxynitride (SiON) layer, an organic or inorganic underlayer, or a combination thereof, are provided on the upper surface of the substrate before coating the photoresist composition of the invention. Such layers, together with an overcoated photoresist layer, form a lithographic material stack.

[0068] Optionally, a layer of adhesion promoter can be applied to the substrate surface before coating with the photoresist composition. If an adhesion promoter is desired, any suitable adhesion promoter for polymer films can be used, such as silanes, typically organosilanes such as trimethoxyvinylsilane, triethoxyvinylsilane, and hexamethyldisilazane, and aminosilane coupling agents such as gamma-aminopropyltriethoxysilane. Particularly suitable adhesion promoters include those sold under the names AP 3000, AP 8000, and AP 9000S, available from DuPont Electronics & Imaging (Marlborough, Massachusetts).

[0069] The photoresist composition can be coated onto a substrate by any suitable method, such as spin coating, spray coating, dip coating, doctor blading, etc. For example, application of a photoresist layer can be achieved by spin-coating the photoresist in a solvent using a coating truck, in which the photoresist is dispensed onto a rotating wafer. During dispensing, the wafer is typically rotated at a speed of up to 4,000 revolutions per minute (rpm), e.g., 200 to 3,000 rpm, e.g., 1,000 to 2,500 rpm, for a period of 15 to 120 seconds to obtain a layer of photoresist composition on the substrate. Those skilled in the art will appreciate that the thickness of the coated layer can be adjusted by varying the rotation speed and / or the solids content of the composition. Photoresist layers formed from the compositions of the present invention typically have a dry layer thickness of 10 to 200 nanometers (nm), preferably 15 to 100 nm, and more preferably 20 to 60 nm.

[0070] The photoresist composition is typically then soft-baked to minimize the solvent content in the layer, thereby forming a tack-free coating and improving adhesion of the layer to the substrate. Soft-baking can be performed, for example, on a hot plate or in an oven, with a hot plate being typical. The soft-baking temperature and time will depend, for example, on the specific photoresist composition and thickness. The soft-baking temperature is typically 90 to 170°C, e.g., 110 to 150°C. The soft-baking time is typically 10 seconds to 20 minutes, e.g., 1 minute to 10 minutes or 1 minute to 5 minutes. The heating time can be easily determined by one skilled in the art based on the components of the composition.

[0071] The photoresist layer is then patternwise exposed to activating radiation to create a solubility differential between exposed and unexposed regions. References herein to exposing a photoresist composition to radiation activating the composition indicate that the radiation can form a latent image in the photoresist composition. Exposure is typically carried out through a patterned photomask having optically transparent and optically opaque regions corresponding to the exposed and unexposed regions of the resist layer, respectively. Alternatively, such exposure can be carried out without a photomask in a direct-write process, typically used for electron beam lithography. Activating radiation typically has a wavelength of sub-400 nm, sub-300 nm, or sub-200 nm, with wavelengths of 248 nm (KrF), 193 nm (ArF), and 13.5 nm (extreme ultraviolet, EUV) or electron beam lithography being preferred. This method is utilized in immersion or dry (non-immersion) lithography techniques. Exposure energies are typically between 1 and 200 millijoules per square centimeter (mJ / cm 2 ), preferably 10 to 100 mJ / cm 2 , more preferably 20 to 50 mJ / cm 2 and depends on the exposure tool and the components of the photoresist composition. In some embodiments, the activating radiation is EUV at a wavelength of 13.5 nm.

[0072] After the photoresist layer is exposed, a post-exposure bake (PEB) of the exposed photoresist layer is performed. PEB can be performed, for example, on a hot plate or in an oven, with a hot plate being typical. PEB conditions will depend, for example, on the specific photoresist composition and layer thickness. PEB is typically performed at a temperature of 80-150°C and for 30-120 seconds. A latent image defined by polarity switching (exposed regions) and polarity non-switching regions (unexposed regions) is formed in the photoresist.

[0073] The exposed photoresist layer is then developed with a suitable developer to selectively remove areas of the layer that are soluble in the developer, while the remaining insoluble areas form a resulting photoresist pattern relief image. In a positive-tone development (PTD) process, the exposed areas of the photoresist layer are removed during development, leaving behind the unexposed areas. Conversely, in a negative-tone development (NTD) process, the exposed areas of the photoresist layer remain, while the unexposed areas are removed during development. Application of the developer can be accomplished by any suitable method, such as those described above for application of the photoresist composition, with spin coating being typical. The development time is effective to remove the soluble areas of the photoresist, typically between 5 and 60 seconds. Development is typically performed at room temperature.

[0074] Suitable developers for the PTD process include aqueous base developers, such as quaternary ammonium hydroxide solutions such as tetramethylammonium hydroxide (TMAH), preferably 0.26N TMAH, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc. Suitable developers for the NTD process are organic solvent-based, meaning that the cumulative content of organic solvent in the developer is 50% by weight or more, typically 95% by weight or more, 95% by weight or more, 98% by weight or more, or 100% by weight, based on the total weight of the developer. Suitable organic solvents for NTD developers include, for example, those selected from ketones, esters, ethers, hydrocarbons, and mixtures thereof. The developer is typically 2-heptanone or n-butyl acetate.

[0075] Coated substrates can be formed from the photoresist compositions of the invention. Such coated substrates include (a) a substrate having one or more layers on a surface thereof, and (b) a layer of a photoresist composition over the one or more layers.

[0076] The photoresist pattern can be used, for example, as an etching mask, thereby allowing the pattern to be transferred to one or more subsequent underlying layers by known etching techniques, typically dry etching such as reactive ion etching. The photoresist pattern can be used, for example, for pattern transfer to an underlying hard mask layer, which in turn is used as an etching mask for pattern transfer to one or more layers below the hard mask layer. If the photoresist pattern is not consumed during pattern transfer, it can be removed from the substrate by known techniques, such as oxygen plasma ashing or a wet strip process. When used in one or more such pattern formation processes, the photoresist composition can be used to manufacture semiconductor devices such as memory devices, processor chips (CPUs), graphics chips, optoelectronic chips, LEDs, OLEDs, and other electronic devices.

[0077] The following non-limiting examples illustrate the present invention. [Example]

[0078] PAG synthesis Example 1 PAG A1 was prepared according to Scheme 1 as described below: [ka]

[0079] To a stirred solution of (±)-1-phenylethanol (compound 1, 50 g, 0.40 mol) and 1,8-diazabicycloundec-7-ene (DBU, 63 g, 0.40 mol) in methylene chloride (300 mL) at 0 °C, chloroacetyl chloride (46.0 g, 0.40 mol) was added dropwise. The mixture was allowed to warm to room temperature, and stirring was continued for 8 h. The organic phase was washed with a saturated aqueous solution of ammonium chloride (2 × 250 mL) and then with water (2 × 250 mL). The solvent was removed from the organic phase to give the crude product. The crude product was dissolved in 20 mL of heptane and first passed through a short plug of silica gel using heptane as the eluent. The product-containing fractions were combined, and the heptane was thoroughly removed under reduced pressure to give the product, 1-phenylethyl-2-chloroacetate (2), as a colorless liquid. Yield: 35 g (43%). 1 H NMR (acetone-d6), δ(ppm):7.75(d,2H,ArH),7.44-3,31(m,5H,ArH),5.94(q,1H,Ar-CH),1.56(d,3H,CH3).

[0080] Under a nitrogen atmosphere, an oven-dried flask was charged with N,N-dimethylformamide (150 mL), compound 2 (20 g, 100 mmol), and (4-hydroxyphenyl)diphenylsulfonium iodide (compound 3, 25 g, 61.3 mmol). The resulting solution was heated to 50°C, and cesium carbonate (25 g, 129.6 mmol) was added in one portion. The reaction mixture was stirred at the same temperature for 36 hours and then cooled to room temperature. The mixture was filtered to remove insoluble salts, and the filtrate solvent was removed under reduced pressure. The remaining residue was dissolved in methylene chloride (150 mL) and washed with water (3 × 150 mL). The methylene chloride was removed under reduced pressure, and the resulting residue was dissolved in 50 mL of acetone and poured into 500 mL of methyl t-butyl ether to give the salt product 4, which was collected and dried under vacuum at 35°C for 24 hours. Yield: 32.0 g (91%). 1H NMR (acetone-d6), δ(ppm):8.20(d,2H,ArH),7.98(d,4H,ArH),7.88(m,2H,ArH),7.83(m,4H) ,ArH),7.41-7.29(m,7H,ArH),5.96(q,1H,Ar-CH),5.06(s,2H,OCH2),1.56(d,3H,CH3).

[0081] To a mixture of salt 4 (10 g, 17.58 mmol) and salt C1 (8.5 g, 19.93 mmol), 100 mL of water and 100 mL of dichloromethane were added. The resulting mixture was stirred at room temperature for 16 hours. The organic phase was separated and washed five times with 100 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to obtain a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of methyl t-butyl ether. A waxy solid of PAG A1 was obtained, which was isolated by decanting the solvent and drying at 35° C. under reduced pressure. Yield: 7.5 g (38%). 1 H NMR (acetone-d6), δ (ppm): 7.94 (m, 8H, ArH), 7.84 (m, 4H, ArH), 7.39 (m, 6H, ArH), 7.35 (m, 1H, ArH), 6.08 (q, 1H, Ar-CH), 5.10 (s, 2H, OCH), 4.33 (q, 2H, OCH), 2.77 (M, 2H, CH2CF2), 1.95-1.5 (14H, adamantane partial protons). 19F NMR δ (ppm): -112.30 (2F, CF2SO3), -119.40 (2F, CH2CF2). A sample of PAG was analyzed for purity by LC-MS. The cation was determined to be >96.0% pure as detected by UV at 232 nm, and the purity detected by positive ion mass spectrometry was >98%. The anion purity as measured by negative ion LC-MS was determined to be greater than 98%.

[0082] Example 2 PAG A2 was prepared according to Scheme 2 as described below: [ka]

[0083] To a mixture of salt 4 (10 g, 17.58 mmol) and salt C2 (7.76 g, 18.27 mmol), prepared as described in Example 1, was added 100 mL of water and 100 mL of dichloromethane. The resulting mixture was stirred at room temperature for 16 hours. The organic phase was separated and washed five times with 100 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to give a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The product, PAG A2, was collected and dried at 35°C under reduced pressure. Yield: 7.5 g (55.7%). A sample of the PAG was analyzed for purity by LC-MS. The cation was determined to be >98.0% pure as detected by UV at 232 nm, and the purity detected by positive ion mass spectrometry was >98%. The anion purity, as measured by negative ion LC-MS, was >98%. 19F NMR δ(ppm)=-110.2(s,2F).

[0084] Example 3 PAG A3 was prepared according to Scheme 3 as described below: [ka]

[0085] To a mixture of salt 4 (10 g, 17.58 mmol) and salt C3 (6.10 g, 18.41 mmol), prepared as described in Example 1, was added 100 mL of water and 100 mL of dichloromethane. The resulting mixture was stirred at room temperature for 24 hours. The organic phase was separated and washed five times with 100 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to obtain a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The product was obtained as an oil and isolated by decanting the solvent. The product, PAG A3, was further dried under reduced pressure at 35°C. Yield: 8.7 g (67.4%). 1H NMR (acetone-d6), δ (ppm): 7.94 (m, 8H, ArH), 7.84 (m, 4H, ArH), 7.39 (m, 6H, ArH), 7.35 (m, 1H, ArH), 6.08 (q, 1H, Ar-CH), 5.10 (s, 2H, OCH). A sample of PAG was analyzed for purity by LC-MS. The cation was determined to be >98.0% pure as detected by UV at 232 nm, and the purity detected by positive ion mass spectrometry was >98%. The anion purity as measured by negative ion LC-MS was >98%.

[0086] Example 4 PAG A4 was prepared according to Scheme 4 as described below: [ka]

[0087] The procedure used for the synthesis of compound 2 in Example 1 was used to prepare compound 6 starting from (±)-1-(4-methylphenyl)ethanol (5) and chloroacetyl chloride. Under a nitrogen atmosphere, an oven-dried flask was charged with N,N-dimethylformamide (150 mL), compound 6 (25 g, 117.55 mmol), and (4-hydroxyphenyl)diphenylsulfonium chloride (compound 3, 20.0 g, 49.2 mmol). The resulting solution was heated to 50°C, and cesium carbonate (25 g, 129.6 mmol) was added in one portion. The reaction mixture was stirred at the same temperature for 36 hours and then cooled to room temperature. The mixture was filtered to remove insoluble salts, and the filtrate solvent was removed under reduced pressure. The remaining residue was dissolved in methylene chloride (150 mL) and washed with water (3 × 150 mL). The methylene chloride was removed under reduced pressure, and the resulting residue was dissolved in 50 mL of acetone and poured into 500 mL of methyl t-butyl ether to give the salt product 7, which was collected and dried under vacuum at 35° C. for 24 hours. Yield: 21.5 g (75%). 1H NMR(acetone-d6),δ(ppm):8.03(d,2H,ArH),7.92(d,4H,ArH),7.88(m,2H,ArH),7.83(m,4H,ArH),7 .41-7.29(7H,ArH),5.93(q,1H,Ar-CH),5.03(s,2H,OCH2),2.30(s,3H,ArCH3),1.52(d,3H,CH3).

[0088] To a mixture of salt 7 (10 g, 171.6 mmol) and salt C1 (11.0 g, 25.80 mmol), 75 mL of water and 75 mL of dichloromethane were added. The resulting mixture was stirred at room temperature for 24 hours. The organic phase was separated and washed five times with 100 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to obtain a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The resulting PAG A4 was collected and dried under reduced pressure at 35°C. Yield: 13.5 g (67%). 1 H NMR (acetone-d6), δ(ppm):7.95-7.89(8H,ArH),7.85-7.81(4H,ArH),7.37(d,2H,ArH),7.27(d,2H,ArH),7.16(d,2H,ArH),5.92(q ,1H,Ar-CH),5.05(s,2H,OCH2),4.33(q,2H,OCH2),2.77(m,2H,CH2CF2),1.95-1.50(14H,adamantane partial proton),1.55(d,3H,CH3).19F NMR δ(ppm):-112.26(2F,CF2SO3),-119.37(2F,CH2CF2).

[0089] Example 5 PAG A5 was prepared according to Scheme 5 as described below: [ka]

[0090] To a mixture of salt 7 (10 g, 17.16 mmol) and salt C4 (11.0 g, 26.3 mmol), 75 mL of water and 75 mL of dichloromethane were added. The resulting mixture was stirred at room temperature for 24 hours. The organic phase was separated and washed five times with 100 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to obtain a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The resulting PAG A5 was collected and dried under reduced pressure at 35°C. Yield: 11.6 g (78%). 1 H NMR (acetone-d), δ (ppm): 7.95-7.82 (12H, ArH), 7.37 (d, 2H, ArH), 7.27 (d, 2H, ArH), 7.18 (d, 2H, ArH), 5.97 (q, 1H, Ar-CH), 5.02 (s, 2H, OCH), 1.55 (d, 3H, CH). F NMR δ (ppm): -77.45 (9F, 3CF). A sample of PAG was analyzed for purity by LC-MS. The cation was determined to be >98.0% pure as detected by UV at 232 nm, and the purity as detected by positive ion mass spectrometry was >98%. The anion purity as measured by negative ion LC-MS was >98%.

[0091] Example 6 PAG A6 was prepared according to Scheme 6 as described below: [ka]

[0092] The procedure used for the synthesis of compound 2 was used to prepare compound 9 starting from (±)-1-(4-biphenyl)ethanol (8) and chloroacetyl chloride. Under a nitrogen atmosphere, an oven-dried flask was charged with N,N-dimethylformamide (150 mL), compound 9 (20.0 g, 72.79 mmol), and (4-hydroxyphenyl)diphenylsulfonium chloride (compound 3, 29.5 g, 72.6 mmol). The resulting solution was heated to 50 °C, and cesium carbonate (20 g, 103.7 mmol) was added in one portion. The reaction mixture was stirred at the same temperature for 24 h and then cooled to room temperature. The mixture was filtered to remove insoluble salts, and the filtrate solvent was removed under reduced pressure. The remaining residue was dissolved in methylene chloride (150 mL) and washed with water (3 × 150 mL). The methylene chloride was removed under reduced pressure, and the resulting residue was dissolved in 50 mL of acetone and poured into 1 L of methyl t-butyl ether to give salt product 10, which was collected and dried under vacuum at 35°C for 24 hours. Yield: 28.5 g (61%). To a mixture of salt 10 (15.0 g, 23.27 mmol) and salt C1 (11.0 g, 25.8 mmol), 75 mL of water and 75 mL of dichloromethane were added. The resulting mixture was stirred at room temperature for 24 hours. The organic phase was separated and washed five times with 100 mL of deionized water each. The solvent from the organic phase was completely removed under reduced pressure to give a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The resulting PAG A6 was collected and dried under reduced pressure at 35°C. Yield: 18.9 g (88%). 1 H NMR (acetone-d6), δ(ppm):7.94-7.79(12H,ArH),7.65(4H,ArH),7.48(4H,ArH),7.40(3H,ArH),6.10(q,1H,Ar-CH), 5.08(s,2H,OCH2),4.33(q,2H,OCH2),2.69(m,2H,CH2CF2),1.80-1.57(14H,adamantane partial proton),1.59(d,3H,CH3).19F NMR δ(ppm):-112.35(2F,CF2SO3),-119.43(2F,CH2CF2).

[0093] Example 7 PAG A7 was prepared according to Scheme 7 as described below: [ka]

[0094] The procedure used for the synthesis of compound 2 was used to prepare compound 11 starting from (±)-1-(4-iodophenyl)ethanol and chloroacetyl chloride. Under a nitrogen atmosphere, an oven-dried flask was charged with N,N-dimethylformamide (100 mL), compound 11 (9.0 g, 27.73 mmol), and (4-hydroxyphenyl)diphenylsulfonium chloride (compound 3, 9.0 g, 22.15 mmol). The resulting solution was heated to 50 °C, and cesium carbonate (20 g, 103.7 mmol) was added in one portion. The reaction mixture was stirred at the same temperature for 24 h and then cooled to room temperature. The mixture was filtered to remove insoluble salts, and the filtrate solvent was removed under reduced pressure. The remaining residue was dissolved in 50 mL of acetone and poured into 500 mL of methyl t-butyl ether to give the salt product 12, which was collected and dried under vacuum at 35 °C for 24 h. Yield: 15.5 g. To a mixture of salt 12 (8.0 g, 11.5 mmol) and salt C1 (5.2 g, 12.2 mmol), 75 mL of water and 75 mL of dichloromethane were added. The resulting mixture was stirred at room temperature for 24 hours. The organic phase was separated and washed five times with 100 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to obtain a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The resulting PAG A7 was collected and dried under reduced pressure at 35° C. Yield: 7.9 g (70%). 1H NMR (acetone-d6), δ(ppm):7.92-7.80(8H,ArH),7.81-7.78(4H,ArH),7.37(d,2H,ArH),7.27(d,2H,ArH),7.16(d,2H,ArH),5.98(q ,1H,Ar-CH),5.10(s,2H,OCH2),4.34(q,2H,OCH2),2.79(m,2H,CH2CF2),1.95-1.50(14H,adamantane partial proton),1.55(d,3H,CH3).19F NMR δ(ppm):-112.26(2F,CF2SO3),-119.37(2F,CH2CF2).

[0095] Example 8 PAG A8 was prepared according to Scheme 8 as described below: [ka]

[0096] The procedure used for the synthesis of compound 2 in Example 1 was used to prepare compound 15 starting from 1-(benzo[b]thiophen-2-yl)ethan-1-ol (14) and chloroacetyl chloride. Under a nitrogen atmosphere, an oven-dried flask was charged with N,N-dimethylformamide (150 mL), compound 15 (8.0 g, 31.4 mmol), and (4-hydroxyphenyl)diphenylsulfonium chloride (compound 3, 8.5 g, 21 mmol). The resulting solution was heated to 50 °C, and cesium carbonate (7.0 g, 36 mmol) was added in one portion. The reaction mixture was stirred at the same temperature for 36 h and then cooled to room temperature. The mixture was filtered to remove insoluble salts, and the filtrate solvent was removed under reduced pressure. The remaining residue was dissolved in 50 mL of acetone and poured into 500 mL of methyl t-butyl ether to give the salt product 16, which was collected and dried under reduced pressure at 35 °C for 24 h. Yield: 8.5 g. To a mixture of salt 16 (8.0 g, 12.8 mmol) and salt C1 (5.5 g, 12.9 mmol), 75 mL of water and 75 mL of dichloromethane were added. The resulting mixture was stirred at room temperature for 24 hours. The organic phase was separated and washed five times with 100 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to obtain a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The resulting PAG A8 was collected and dried under reduced pressure at 35° C. Yield: 6.9 g (60%). 1 H NMR(acetone-d6),δ(ppm):7.96-7.76(12H,ArH),7.40-7.30(6H,ArH),6.36(q,1H,Ar-CH),5.07(s,2H,O CH2),4.30(q,2H,OCH2),2.69(m,2H,CH2CF2),1.95-1.50(14H,adamantane partial proton),1.55(d,3H,CH3).19F NMR δ(ppm):-112.4(2F,CF2SO3),-119.68(2F,CH2CF2).

[0097] Example 9 PAG A9 was prepared according to Scheme 9 as described below: [ka]

[0098] Under a nitrogen atmosphere, an oven-dried flask was charged with N,N-dimethylformamide (250 mL), 1-phenylethyl 2-chloroacetate (Compound 2, 25 g, 125.8 mmol), and 5-(4-hydroxy-3,5-dimethylphenyl)-5H-dibenzo[b,d]thiophenium bromide (Compound 17, 38.5 g, 100 mmol). The resulting solution was heated to 50 °C, and cesium carbonate (25.0 g, 130.0 mmol) was added in one portion. The reaction mixture was stirred at the same temperature for 36 hours and then cooled to room temperature. The mixture was filtered to remove insoluble salts, and the filtrate solvent was removed under reduced pressure. Most of the N,N-dimethylformamide was removed by distillation under reduced pressure, and the resulting residue was poured into a saturated aqueous solution of ammonium chloride. The resulting solid was filtered, air-dried, dissolved in dichloromethane (50 mL), and poured into 500 mL of methyl t-butyl ether (MTBE). The resulting residue was suspended in acetone (100 mL) to form a white solid, salt product 18, which was filtered and dried to yield 22.5 g. To a mixture of salt 18 (10.0 g, 18.20 mmol) and salt C1 (7.9 g, 18.52 mmol), 100 mL of water and 100 mL of dichloromethane were added. The resulting mixture was stirred at room temperature for 24 hours. The organic phase was separated and washed five times with 50 mL of deionized water. The solvent from the organic phase was completely removed under reduced pressure to obtain a waxy crude product. The crude product was dissolved in 50 mL of acetone and poured into 500 mL of heptane. The resulting PAG A9 was collected and dried under reduced pressure at 35 °C. Yield: 12.8 g (75%). 1H NMR(acetone-d6),δ(ppm):8.53(d,2H,ArH),8.37(d,2H,ArH),8.03(t,2H,ArH),7.83(t,2H,ArH),7.52(s,2H,ArH),7.41-7.30(m,6H,ArH),6.0(q ,1H,Ar-CH),4.62(s,2H,OCH2),4.33(q,2H,OCH2),2.69(m,2H,CH2CF2),2.30(6H,2CH3),1.95-1.50(14H,adamantane partial proton),1.55(d,3H,CH3).19F NMR δ(ppm):-112.2(2F,CF2SO3),-119.54(2F,CH2CF2).

[0099] Example 10 PAG A10 was prepared according to Scheme 10 as described below: [ka]

[0100] The procedure used for the synthesis of PAG A9 was used for the preparation of PAG A10 starting from salt C4 and salt 18. 1 H NMR (acetone-d6), δ(ppm):8.53(d,2H,ArH),8.33(d,2H,ArH),8.04(t,2H,ArH),7.88(t,2H,ArH),7.50(s,2H) ,ArH),7.43-7.30(m,6H,ArH),5.99(q,1H,Ar-CH),4.71(s,2H,OCH2),2.29(6H,2CH3),55(d,3H,CH3).19F NMR δ(ppm):-77.45(9F,3CF3).

[0101] Photoresist Composition and Lithography Evaluation Photoresist compositions were prepared and lithographic processing and evaluation was carried out as described below: [ka]

[0102] Examples 11 to 21 Photoresist compositions were prepared by dissolving the solid components in a solvent to a total solids content of 1.5 wt. % using the materials and proportions shown in Table 1. The resulting mixture was shaken on a mechanical shaker and then filtered through a PTFE disk filter with a 0.2 micron pore size. Each 200 mm silicon wafer overcoated with a BARC stack (60 nm thick AR™ 3 antireflective material [DuPont Electronics & Imaging] on 80 nm thick AR™ 40A antireflective material) was spin-coated with each photoresist composition using a TEL Clean Track ACT 8 wafer track and soft-baked at 110°C for 60 seconds to obtain a photoresist layer with a target thickness of approximately 40 nm. Resist layer thicknesses were measured using a THERMA-WAVE OP7350. The wafers were subjected to a 3-53 mJ / cm2 spin-coating. 2 The wafers were exposed to 248 nm radiation using a Canon FPA-5000 ES4 scanner at an exposure dose of 1000 nm. The wafers were post-exposure baked at 100°C for 60 seconds, developed in MF™-CD26 TMAH developer (DuPont Electronics & Imaging) for 60 seconds, rinsed with deionized water, and dried. Photoresist layer thickness measurements were taken in the exposed and unexposed areas of the layer. A contrast curve was generated for each wafer by plotting the remaining photoresist layer thickness in the exposed areas against dose. Dose vs. clear (E0) was determined from the contrast curve as the exposure dose at which the remaining photoresist layer thickness was less than 10% of the original coated thickness. Unexposed film thickness loss (UFTL) was determined based on the photoresist layer thickness measurements in the unexposed areas. The results are shown in Table 1.

[0103] [Table 1]

[0104] Examples 22 to 29 Photoresist compositions were prepared using the materials and proportions shown in Table 2 by dissolving the solid components in a solvent to a total solids content of 1.5 wt%. The resulting mixture was shaken on a mechanical shaker and then filtered through a PTFE disk filter with a 0.2 micron pore size. Each 200 mm silicon wafer overcoated with a BARC stack (60 nm thick AR™ 3 antireflective material [DuPont Electronics & Imaging] on 80 nm thick AR™ 40A antireflective material) was spin-coated with each photoresist composition using a TEL Clean Track ACT 8 wafer track and soft-baked at 110°C for 60 seconds to obtain a photoresist layer with a target thickness of approximately 40 nm. Resist layer thicknesses were measured using a THERMA-WAVE OP7350. The wafers were subjected to a 3-53 mJ / cm2 spin-coating. 2 The wafers were exposed to 248 nm radiation using a Canon FPA-5000 ES4 scanner at an exposure dose of 100 s. The wafers were post-exposure baked at 100°C for 60 seconds, developed in MF™-CD26 TMAH developer (DuPont Electronics & Imaging) for 60 seconds, rinsed with deionized water, and dried. Photoresist layer thickness measurements were taken in the exposed areas of the layer. A contrast curve for each wafer was generated, and E was determined from the contrast curve as described above. An additional contrast curve was generated for each wafer by plotting the normalized photoresist layer thickness in the exposed area against the logarithm of the dose. The contrast (γ) was determined from the normalized contrast curve as the slope between the 80% and 20% photoresist film thickness points. The results are shown in Table 2.

[0105] [Table 2]

[0106] Examples 30 to 34 Photoresist compositions were prepared by dissolving the solid components in a solvent to a total solids content of 4.3 wt. % using the materials and proportions shown in Table 3. The resulting mixture was shaken on a mechanical shaker and then filtered through a 0.2 micrometer pore size PTFE disk filter. 200 mm silicon wafers overcoated with a BARC stack (60 nm thick AR™ 3 antireflective material [DuPont Electronics & Imaging] on 80 nm thick AR™ 40A antireflective material) were each spin-coated with each photoresist composition using a TEL Clean Track ACT 8 wafer track and soft-baked at 110°C for 60 seconds to yield a photoresist layer approximately 120 nm thick. Each wafer was exposed to 248 nm radiation using a Canon FPA 5000 ES4 scanner (NA=0.8, Outer Sigma=0.85, Inner Sigma=0.57) with a mask containing a 1:1 contact hole pattern with a 200 nm diameter and 400 nm pitch. The wafers were post-exposure baked at 100°C for 60 seconds, developed with MF™-CD26 TMAH developer (DuPont Electronics & Imaging) for 60 seconds, rinsed with deionized water, and dried. Critical dimension (CD) measurements of the formed contact hole patterns were performed with a Hitachi S-9380 CD SEM. The sizing energy (E size The EL, exposure latitude (EL), and CD uniformity (3σ) (CDU) were determined based on the CD measurements. The sizing energy is the exposure energy at which a target 200 nm diameter / 400 nm pitch contact hole pattern was resolved. The exposure latitude is the difference in exposure energy required to print contact holes at ±10% of the target diameter, normalized by the sizing energy. The results are shown in Table 3.

[0107] [Table 3]

[0108] Examples 35-36 Photoresist compositions were prepared using the materials and proportions shown in Table 4 by dissolving the solid components in a solvent to a total solids content of 1.55 wt%. The resulting mixture was shaken on a mechanical shaker and then filtered through a PTFE disk filter with a 0.2 micron pore size. A 200 mm silicon wafer overcoated with an approximately 50 Å thick organic BARC layer was diced into coupons. Each coupon was spin-coated with the respective photoresist composition and soft-baked at 110°C for 90 seconds to obtain a 40 nm thick photoresist layer. The photoresist-coated coupons were exposed to electron beam radiation using a JEOL Ltd. JBX-9500FS electron beam lithography system to print a 1:1 contact hole pattern with a 35 nm diameter and 70 nm pitch. The coupons were post-exposure baked at 90°C for 60 seconds, developed in MF™-CD26 TMAH developer (DuPont Electronics & Imaging) for 45 seconds, rinsed with deionized water, and dried. Scanning electron microscopy was performed on a Hitachi S-9380 CD SEM to collect images and analyze the printed patterns. CD measurements of the contact hole patterns were performed based on the SEM images using Fractilia MetroLER metrology software. Sizing energy (E size The sizing energy was the irradiation energy at which a target contact hole pattern with a diameter of 35 nm was resolved. The CDU was calculated based on the CD of 35 contact holes. The results are shown in Table 4.

[0109] [Table 4]

Claims

1. Formula (2-1): 【Chemistry 1】 (In the formula: Ar １ each independently represents a substituted or unsubstituted aryl group; R １ independently represent an alkyl or aryl group, each of which may be substituted or unsubstituted, where Ar １ and R １ are optionally joined to each other by a single bond or a divalent linking group to form a ring; Y independently represents a single bond or —CH 2 —O—*, where * is the point of attachment to Ar 2 ; Ar ２ each independently represents a substituted or unsubstituted arylene group; X is S or I; R ２ each independently represents a substituted or unsubstituted alkyl or aryl group; Z － is a counter anion; a is from 1 to Ar ２ when X is S, b is 1, 2, or 3, and c is 3; when X is I, b is 1 or 2, and c is 2; where (i) two R ２ or (ii) one Ar ２ group and one R ２ The groups are optionally joined to each other by a single bond or a divalent linking group to form a ring. A photoacid generator represented by the formula:

2. Formula (2-1): 【Chemistry 2】 (In the formula: Ar １ independently represent a substituted or unsubstituted aryl group, and when Ar 1 is substituted, the substituents are nitro, cyano, amino, mono- or di-(C 1-6 )alkylamino, alkanoyl, formyl, carboxylic acid or an alkali metal salt or ammonium salt thereof, ester, amide (-C(=O)NR 2 (wherein R is hydrogen or C 1-6 alkyl)), carboxamide (-CH 2 C(=O)NR 2 (wherein R is hydrogen or C 1-6 alkyl)), halogen, thiol, C 1-6 alkylthio, thiocyano, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 1-6 haloalkyl, C 1-9 alkoxy, C 1-6 haloalkoxy, C 3-12 cycloalkyl, C 5-18 cycloalkenyl, C 6-12 R is selected from aryl, C 7-19 arylalkyl having 1 to 3 separate or fused rings and 6 to 18 ring carbon atoms, arylalkoxy having 1 to 3 separate or fused rings and 6 to 18 ring carbon atoms, C 7-12 alkylaryl, C 4-12 heterocycloalkyl, C 3-12 heteroaryl, C 1-6 alkylsulfonyl, C 6-12 arylsulfonyl, tosyl, vinyl, and vinyl-containing groups; １ independently represent an alkyl or aryl group, each of which may be substituted or unsubstituted, where Ar １ and R １ are optionally linked to each other by a single bond or a divalent linking group to form a ring; Y independently represents a single bond or a divalent group; Ar ２ each independently represents a substituted or unsubstituted arylene group; X is S or I; R ２ each independently represents a substituted or unsubstituted alkyl or aryl group; Z － is a counter anion; a is from 1 to Ar ２ when X is S, b is 1, 2, or 3, and c is 3; when X is I, b is 1 or 2, and c is 2; where (i) two R ２ or (ii) one Ar ２ group and one R ２ The groups are optionally joined to each other by a single bond or a divalent linking group to form a ring. A photoacid generator represented by the formula:

3. Formula (1): 【Transformation 3】 (In the formula: Ar １ is a substituted or unsubstituted aryl group; R １ are alkyl or aryl groups, each of which may be substituted or unsubstituted, where Ar １ and R １ are optionally joined to each other by a single bond or a divalent linking group to form a ring; Y is a single bond or a divalent group; and * is the point of attachment of the moiety to another atom of the photoacid generator. A photoacid generator that is non-ionic, comprising the moiety:

4. 3. The photoacid generator according to claim 1, wherein X is S.

5. 3. The photoacid generator according to claim 1, wherein X is I.

6. Ar １ The photoacid generator according to claim 1 or 2, wherein is a substituted aryl group.

7. The photoacid generator of any one of claims 1 to 6, wherein the photoacid generator is in a polymeric form.

8. A photoresist composition comprising the photoacid generator according to any one of claims 1 to 7 and a solvent.

9. The photoresist composition of claim 8 , wherein the photoresist composition comprises an acid-sensitive polymer.

10. A pattern formation method, comprising: (a) forming a photoresist layer on a substrate from the photoresist composition of claim 8 or 9; (b) exposing the photoresist layer to activating radiation; (c) developing the exposed photoresist layer to provide a resist relief image; A method comprising:

Images