Photoactive compounds, photoresist compositions including the same, and pattern formation methods

Abstract

A photoactive compound of formula (1a) or (1b): wherein R 1is substituted or unsubstituted C 1-30alkyl, substituted or unsubstituted C 3-30cycloalkyl, substituted or unsubstituted C 3-30heterocycloalkyl, substituted or unsubstituted C 6-30aryl, or substituted or unsubstituted C 3-30heteroaryl comprising an aromatic ring heteroatom chosen from nitrogen, oxygen, or a combination thereof; R 2and R 3are as provided herein; R 4is substituted or unsubstituted C 1-30alkyl, substituted or unsubstituted C 3-30cycloalkyl, substituted or unsubstituted C 3-30heterocycloalkyl, substituted or unsubstituted C 6-30aryl, or substituted or unsubstituted C 3-30heteroaryl; and M +is an organic cation.

Description

[Technical Field]

[0001] This invention relates to photoactive compounds for use in photoresist compositions and a method for patterning using such photoresist compositions. This invention has found applicability in photolithography applications within the semiconductor manufacturing industry. [Previous Technology]

[0002] Photoresist materials are typically used to transfer images onto one or more underlying layers (such as metals, semiconductors, or dielectric layers) deposited on a substrate. To increase the integration density of semiconductor devices and allow the formation of structures with dimensions in the nanometer range, photoresists and photolithography tools with high resolution capabilities have been developed.

[0003] Chemically enhanced photoresists are commonly used in high-resolution processing. These resists typically employ a polymer with acid-indestabilized groups, a photoacid generator, and an acid quencher. The acid generator forms acid by patterning exposure to activating radiation through a photomask. During post-exposure baking, this acid cleaves the acid-indestabilized groups in the exposed regions of the polymer. An acid quencher is typically added to the photoresist composition to control the diffusion of acid into unexposed areas, thereby improving contrast. The result of the photolithography process is a difference in solubility characteristics between exposed and unexposed areas of the resist in the developer solution. During positive development (PTD), the exposed areas of the photoresist layer dissolve in the developer and are removed from the substrate surface, while the unexposed areas, insoluble in the developer, are retained after development to form a positive image. The resulting embossed image allows for selective processing of the substrate.

[0004] Non-photoactive acid quenching materials commonly used in chemically reinforced resists include straight-chain aliphatic amines, cyclic aliphatic amines, aromatic amines, straight-chain and cyclic amides and their derivatives. Another commonly used class of acid quenching materials is photoactive quenchers, also known as photodegradable quenchers or photodegradable quenchers. Photoactive quenchers have also been used in chemically reinforced resist compositions. Photodegradable quenchers are typically salts containing photoactive onium cations and anions, where the anion is the conjugate base of a weak acid. Before exposure, the salt acts as a base or acid quencher. After exposure, the anionic portion of the photodegradable quencher becomes protonated and thus becomes more acidic. Therefore, when a chemically reinforced resist containing a photodegradable quencher is irradiated, the concentration of the acid quencher in the exposed area decreases sharply. On the other hand, intact photodegradable quenchers in unexposed areas can capture acid molecules that diffuse from exposed areas during photolithography, thereby improving photolithography performance.

[0005] Photoresist compositions containing photodegradable quenchers and their uses have been described in the art. However, for many other applications, there is a need for novel photoresists that can provide high-resolution line-space characteristics with superior line edge roughness (LWR) and wider depth of focus (DOF). [Summary of the Invention]

[0006] A photoactive compound having formula (1a) or (1b) is provided: (1a) (1b) wherein R1 is a substituted or unsubstituted C1-30 alkyl, a substituted or unsubstituted C3-30 cycloalkyl, a substituted or unsubstituted C3-30 heterocycloalkyl, a substituted or unsubstituted C6-30 aryl, or a substituted or unsubstituted C3-30 heteroaryl containing an aromatic ring heteroatom selected from nitrogen, oxygen, or combinations thereof; R2 is hydrogen, halogen, a substituted or unsubstituted C1-30 alkyl, a substituted or unsubstituted C1-30 heteroalkyl, a substituted or unsubstituted C3-30 cycloalkyl, a substituted or unsubstituted C3-30 heterocycloalkyl, a substituted or unsubstituted C2-30 alkenyl, a substituted or unsubstituted C2-30 alkynyl, a substituted or unsubstituted C1-C30 alkoxy, a substituted or unsubstituted C1-C30 alkoxy, a substituted or unsubstituted C1-C30 alkoxy, a substituted or unsubstituted C1-C30 alkoxy, a substituted or unsubstituted C6 ... R30 is an alkylthioyl group, a substituted or unsubstituted C3-C10 cycloalkenyl group, a substituted or unsubstituted C3-C10 heterocyclic alkenyl group, a substituted or unsubstituted C6-30 aryl group, a substituted or unsubstituted C7-30 arylalkyl group, a substituted or unsubstituted C7-30 alkylaryl group, or a substituted or unsubstituted C6-C30 aryloxy group; R3 is a hydrogen or non-hydrogen substituent; R4 is a substituted or unsubstituted C1-30 alkyl group, a substituted or unsubstituted C3-30 cycloalkyl group, a substituted or unsubstituted C3-30 heterocyclic alkyl group, a substituted or unsubstituted C6-30 aryl group, or a substituted or unsubstituted C3-30 heteroaryl group; each of R2, R3 and R4 may further include, as required, one or more divalent linking groups as part of its structure, wherein each of the one or more divalent linking groups is independently substituted or unsubstituted; R2 and R 3. It is required to form a ring, which is required to further include one or more divalent linking groups as part of its structure, wherein each of the one or more divalent linking groups is substituted or unsubstituted, and wherein the ring is substituted or unsubstituted; and M+ is an organic cation.

[0007] On the other hand, a photoresist composition is provided, which includes a photoactive compound and a solvent.

[0008] Another aspect provides a method for forming a pattern, the method comprising: (a) forming a photoresist layer from a photoresist composition; (b) exposing the photoresist layer to activation radiation in a patterned manner; and (c) developing the exposed photoresist layer to provide a resist relief image.

Implementation Method

[0010] Exemplary embodiments, examples of which are shown in this specification, will now be described in detail. In this regard, these exemplary embodiments may take different forms and should not be construed as limited to the description shown herein. Therefore, the exemplary embodiments are described below only by reference to the accompanying drawings to explain various aspects of this specification. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. When a statement such as "at least one / of..." precedes the list of elements, it modifies the entire list of elements and does not modify any individual element in the list.

[0011] As used herein, the terms "a / an" and "the" do not indicate a limitation of quantity and are to be construed as including both the singular and plural unless otherwise indicated herein or clearly contradicted by the context. Unless otherwise explicitly stated, "or" means "and / or". The modifier "about" used in conjunction with quantity includes the stated value and has the meaning specified by the context (e.g., including the degree of error associated with a particular quantity of measurement). The entire scope disclosed herein includes endpoints, and such endpoints can be independently combined with each other. The suffix "(s)" is intended to include both the singular and plural of the term it modifies, thereby including at least one of the stated terms. "As needed" or "as required" means that an event or situation subsequently described may or may not occur, and the description includes instances where the event occurs as well as instances where it does not occur. The terms "first," "second," and similar terms herein do not indicate order, quantity, or importance, but are used to distinguish one element from another. When an element is said to be "on" another element, it can be in direct contact with that other element or an insert element may exist therein. In contrast, when an element is said to be "directly" "on" another element, no insert element exists. It should be understood that the components, elements, limitations, and / or features of the described aspects can be combined in any suitable manner in the aspects.

[0012] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms (such as those defined in common dictionaries) shall be interpreted as having the same meaning as they have in the relevant field and in the context of this disclosure, and shall not be interpreted as having an idealized or overly formal meaning unless expressly defined herein.

[0013] As used herein, "photochemical rays" or "radiation" means, for example, the bright-line spectrum of a mercury lamp, far-ultraviolet light represented by a quaternary molecular laser, extreme ultraviolet light (EUV light), X-rays, particle rays (such as electron beams and ion beams), etc. Furthermore, in this invention, "light" means photochemical rays or radiation.

[0014] Argon fluoride lasers (ArF lasers) are a special type of excimer laser, sometimes called excimer lasers. "Ar" is an abbreviation for "excited dimer," and "excimer" is an abbreviation for "excited complex." Excimer lasers use a mixture of rare gases (argon, krypton, or xenon) and halogen gases (fluorine or chlorine), which, under appropriate electrical stimulation and high voltage conditions, emit coherent stimulated emission (laser) in the ultraviolet range.

[0015] In addition, unless otherwise stated, “exposure” in this specification includes not only exposure by mercury lamps, far ultraviolet light represented by precipitated molecular lasers, X-rays, extreme ultraviolet light (EUV light), etc., but also writing with particle beams (such as electron beams and ion beams).

[0016] As used herein, the term "hydrocarbon" refers to an organic compound or group having at least one carbon atom and at least one hydrogen atom; "alkyl" refers to a straight-chain or branched saturated hydrocarbon group having a specified number of carbon atoms and a valence of 1; "alkylene" refers to an alkyl group having a valence of 2; "hydroxyalkyl" refers to an alkyl group substituted with at least one hydroxyl group (-OH); "alkoxy" refers to "alkyl-O-"; "carboxyl" and "carboxylic acid" refer to groups having the formula "-C(=O)-OH"; "cycloalkyl" refers to a monovalent group having one or more saturated rings in which all ring members are carbon atoms; "cycloalkylene" refers to a cycloalkyl group having a valence of 2; "alkenyl" refers to a straight-chain or branched monovalent hydrocarbon group having at least one carbon-carbon double bond; "alkenoxy" refers to "alkenyl-O-"; "alkenylene" refers to an alkenyl group having a valence of 2. "Cycloalkenyl" refers to a non-aromatic cyclic monovalent hydrocarbon group having at least three carbon atoms and at least one carbon-carbon double bond; "Alynyl" refers to a monovalent hydrocarbon group having at least one carbon-carbon triple bond; the term "aromatic group" refers to a monocyclic or polycyclic ring system that satisfies Hückel's rule and includes a carbon atom in the ring, and may include one or more heteroatoms selected from N, O, and S to replace the carbon atoms in the ring, as needed; "aryl" refers to a monovalent aromatic monocyclic or polycyclic ring system in which each ring member is carbon, and may include a group having an aromatic ring fused to at least one cycloalkyl or heterocyclic alkyl ring; "arylaryl" refers to an aryl group having a valence of 2; "alkylaryl" refers to an aryl group that has been substituted with an alkyl group; "arylalkyl" refers to an alkyl group that has been substituted with an aryl group; "aryloxy" refers to "aryl-O-"; and "arylthio" refers to "aryl-S-".

[0017] The prefix "hetero" means that the compound or group includes at least one member (e.g., 1, 2, 3, or 4 or more heteroatoms) that is a heteroatom in place of a carbon atom, wherein each of the one or more heteroatoms is independently N, O, S, Si, or P; "heteroatom-containing group" refers to a substituent that includes at least one heteroatom; "heteroalkyl" refers to an alkyl group having at least one heteroatom in place of a carbon atom; "heterocyclic alkyl" refers to a cycloalkyl group having at least one heteroatom as a ring member in place of a carbon atom; "heterocyclic alkyl" refers to a heterocyclic alkyl group having a valence of 2.

[0018] The term "heteroaryl" refers to an aromatic 4-8 member monocyclic, 8-12 member bicyclic, or 11-14 member tricyclic ring system having 1-4 heteroatoms (if monocyclic), 1-6 heteroatoms (if bicyclic), or 1-9 heteroatoms (if tricyclic), wherein each heteroatom is independently selected from N, O, S, Si, or P (e.g., if monocyclic, bicyclic, or tricyclic, then carbon atom and 1-3, 1-6, or 1-9 N, O, or S heteroatoms, respectively). Examples of heteroaryl groups include pyridyl, furanyl (furyl or furanyl), imidazole, benzimidazolyl, pyrimidinyl, thiophenyl or thienyl, quinolinyl, indole, thiazolyl, etc.

[0019] Unless otherwise expressly provided, each of the aforementioned substituents may be substituted as desired. The term "substituted as desired" means substituted or unsubstituted. "Substituted" means that at least one hydrogen atom of the chemical structure is substituted by another terminal substituent group, typically monovalent, provided that the normal valence of the specified atom is not exceeded. When the substituent is a side-oxygen group (i.e., =O), the two twin hydrogen atoms on the carbon atom are substituted by the terminal side-oxygen group. Combinations of substituents or variations are permissible. Exemplary substituents that may be present at the "substituted" position include, but are not limited to, nitro (-NO₂), cyano (-CN), hydroxyl (-OH), oxy (=O), amino (-NH₂), mono- or di-(C₁-6)alkylamino, alkylyl (such as C₂-6 alkylyl such as acetyl), methylamino (-C(=O)H), carboxylic acids or their alkali metal salts or ammonium salts; esters (including acrylates, methacrylates and lactones) such as C₂-6 alkyl esters (-C(=O)O-alkyl or -OC(=O)-alkyl) and C₇-13 aryl esters (-C(=O)O-alkyl or -OC(=O)-aryl), acetamino (-C(=O)NR₂, where R is hydrogen or C₁-6 alkyl), methylamino (-CH₂C(=O)NR₂, where R is hydrogen or C₁-6 alkyl). C1-6 alkyl), halogen, mercapto (-SH), C1-6 alkylthio (-S-alkyl), thiocyano (-SCN), C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C1-6 haloalkyl, C1-9 alkoxy, C1-6 haloalkoxy, C3-12 cycloalkyl, C5-18 cycloalkenyl, C2-18 heterocyclic alkenyl, C6-12 aryl having at least one aromatic ring (e.g., phenyl, biphenyl, naphthyl, etc., each ring system substituted or unsubstituted aromatic), C7-19 arylalkyl having 1 to 3 single or fused rings and 6 to 18 cyclic carbon atoms, arylalkoxy having 1 to 3 single or fused rings and 6 to 18 cyclic carbon atoms, C7-12 alkylaryl, C3-12 heterocyclic alkyl, C3-12 heteroaryl, C 1-6 alkylsulfonyl (-S(=O) 2-alkyl), C6-12 arylsulfonyl (-S(=O) 2-aryl), or toluenesulfonyl (CH3C6H4SO2-). When the group is substituted, the indicated carbon number is the total number of carbon atoms in the group, excluding those with any substituents. For example, the group -CH2CH2CN is a cyano-substituted C2 alkyl.

[0020] The term "halogen" means a monovalent substituent of fluorine (fluorinated), chlorine (chloroinated), bromine (brominated), or iodine (iodinated). The prefix "halogenated" means a group containing one or more of the fluorine, chlorine, bromine, or iodine substituents that replace a hydrogen atom. Combinations of halogen groups (e.g., bromine and fluorine) or only fluorine groups may be present. For example, the term "halogenated alkyl" refers to an alkyl group substituted with one or more halogens. As used herein, "substituted C1-8 haloalkyl" means a C1-8 alkyl group substituted with at least one halogen and further substituted with one or more other substituents that are not halogens. It should be understood that substitution of a group with a halogen atom should not be considered as a heteroatom-containing group, since the halogen atom does not substitute for a carbon atom.

[0021] As used herein, "acid-indestructible group" refers to a group in which a bond is broken by the catalytic action of an acid (as desired and typically in conjunction with heat treatment), resulting in the formation of a polar group (such as a carboxylic acid or alcohol group, formed on the polymer) and, as desired and typically, a portion connected to the broken bond that is disconnected from the polymer. In other systems, nonpolymerized compounds may include acid-indestructible groups that can be cleaved by the catalytic action of an acid, resulting in the formation of a polar group, such as a carboxylic acid or alcohol group, on the cleaved portion of the nonpolymerized compound. Such acids are typically photogenerated acids under conditions of bond cleavage during post-exposure baking; however, embodiments are not limited thereto, and such acids may, for example, be thermally generated. Suitable acid-indestructible groups include, for example: tertiary alkyl ester groups, secondary or tertiary aryl ester groups, secondary or tertiary ester groups having a combination of alkyl and aryl groups, tertiary alkoxy groups, acetal groups, or ketal groups. Acid-instable groups are also commonly referred to in the art as "acid-crackable groups", "acid-crackable protecting groups", "acid-instable protecting groups", "acid-degradable groups", "acid-sensitive groups" and "acid-decomposable groups".

[0022] As used herein, unless otherwise defined, "divalent linking group" means a divalent group including -O-, -S-, -Te-, -Se-, -C(O)-, -N(Ra)-, -S(O)-, -S(O)2-, -C(S)-, -C(Te)-, -C(Se)-, substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocycloalkyl, substituted or unsubstituted C6-30 aryl, substituted or unsubstituted C3-30 heteroaryl, or combinations thereof, wherein Ra is a hydrogen group, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C1-20 heteroalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl. Typically, the divalent linking group includes one or more of the following: -O-, -S-, -C(O)-, -N(Ra)-, -S(O)-, -S(O)2-, substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocycloalkyl, substituted or unsubstituted C6-30 aryl, substituted or unsubstituted C3-30 heteroaryl, or combinations thereof, wherein Ra is a hydrogen group, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C1-20 heteroalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl. More typically, the divalent linking group includes at least one of the following: -O-, -C(O)-, -C(O)O-, -N(Ra)-, -C(O)N(Ra)-, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C3-10 cycloalkyl, substituted or unsubstituted C3-10 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, substituted or unsubstituted C3-10 heteroaryl, or combinations thereof, wherein Ra is a hydrogen group, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl.

[0023] This invention relates to photoactive compounds, such as photodegradable quencher (PDQ) compounds. In particular, the photoactive compounds of this invention are salts comprising α,β-unsaturated carboxylate salts, which can be used in photoresist compositions to achieve improved roughness of print features and a wider DOF.

[0024] The photoactive compound has formula (1a) or (1b): (1a)(1b)

[0025] In formula (1a), R1 refers to substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocycloalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl containing an aromatic cyclic heteroatom selected from nitrogen, oxygen or combinations thereof. Preferably, R1 can be a substituted or unsubstituted C3-20 cycloalkyl, a substituted or unsubstituted C3-20 heterocycloalkyl, a substituted or unsubstituted C6-20 aryl, or a substituted or unsubstituted C3-20 heteroaryl containing an aromatic ring heteroatom selected from nitrogen or oxygen. Typically, R1 can be a substituted or unsubstituted C6-20 aryl or a substituted or unsubstituted C3-20 heteroaryl containing an aromatic ring heteroatom selected from nitrogen or oxygen, wherein the substituted C6-20 aryl and the substituted C3-20 heteroaryl can each be independently substituted by at least one of a halogen, a hydroxyl group, a substituted or unsubstituted C1-10 alkyl, a substituted or unsubstituted C6-C20 aryl, a substituted or unsubstituted C6-C20 aryloxy, a substituted or unsubstituted C3-C20 heteroaryl, or a group having the formula -C(O)OR8, wherein R 8 can be a substituted or unsubstituted C1-10 alkyl, a substituted or unsubstituted C3-10 cycloalkyl, a substituted or unsubstituted C6-10 aryl, or a substituted or unsubstituted C3-10 heteroaryl.

[0026] In formula (1a), R2 is hydrogen, halogen, substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C1-30 heteroalkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocycloalkyl, substituted or unsubstituted C2-30 alkenyl, substituted or unsubstituted C2-30 alkynyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 alkylthio, substituted or unsubstituted C3-C10 cycloalkenyl, substituted or unsubstituted C3-C10 heterocycloalkenyl, substituted or unsubstituted C6-30 aryl, substituted or unsubstituted C7-30 arylalkyl, substituted or unsubstituted C7-30 alkylaryl, or substituted or unsubstituted C6-C30 aryloxy. Preferably, R2 can be hydrogen, halogen, or substituted or unsubstituted C1-10 alkyl, and typically R2 can be hydrogen.

[0027] In formula (1a), each of R2 and R3 may further include one or more divalent linking groups as part of its structure, wherein each of the one or more divalent linking groups is independently substituted or unsubstituted.

[0028] In formula (1a), R2 and R3 together form a ring as required, which may further include one or more divalent linking groups as part of its structure, wherein each of the one or more divalent linking groups is substituted or unsubstituted, and wherein the ring is substituted or unsubstituted.

[0029] In formula (1a), R3 is hydrogen or a non-hydrogen substituent. For example, R3 can be hydrogen, or a substituted or unsubstituted C1-20 organic group. In some embodiments, R3 can be a C1-20 organic group further comprising -C(O)-, -C(O)O-, -C(O)N(R5)-, or combinations thereof, wherein R5 is hydrogen, a substituted or unsubstituted C1-10 alkyl, a substituted or unsubstituted C1-10 heteroalkyl, a substituted or unsubstituted C6-10 aryl, or a substituted or unsubstituted C3-10 heteroaryl. In other embodiments, R3 can be a halogen atom, a cyano group, or a substituted or unsubstituted C1-5 haloalkyl. In some aspects, when R1 is a substituted or unsubstituted C6-30 aryl, R3 is not hydrogen or a halogen.

[0030] In formula (1b), R4 is a substituted or unsubstituted C1-30 alkyl, a substituted or unsubstituted C3-30 cycloalkyl, a substituted or unsubstituted C3-30 heterocycloalkyl, a substituted or unsubstituted C6-30 aryl, or a substituted or unsubstituted C3-30 heteroaryl. Preferably, R4 can be a substituted or unsubstituted C3-20 cycloalkyl, a substituted or unsubstituted C3-20 heterocycloalkyl, a substituted or unsubstituted C6-20 aryl, or a substituted or unsubstituted C3-20 heteroaryl. For example, R4 may be a substituted or unsubstituted C6-18 aryl group, or a substituted or unsubstituted C3-18 heteroaryl group, wherein the substituted C6-18 aryl group and the substituted C3-18 heteroaryl group are each substituted by at least one of the following: halogen, amino (-NH2), mono- or di-(C1-6)alkylamino group, substituted or unsubstituted C1-6 alkyl group, substituted or unsubstituted C1-6 haloalkyl group, substituted or unsubstituted C1-9 alkoxy group, substituted or unsubstituted C2-6 alkenyl group, substituted or unsubstituted C6-12 aryl group, substituted or unsubstituted C3-12 heteroaryl group, or a combination thereof. R4 may further include, as desired, one or more divalent linking groups as part of its structure, wherein each of the one or more divalent linking groups is independently substituted or unsubstituted.

[0031] In formulas (1a) and (1b), M+ is an organic cation. For example, M+ can be a strontium cation or an iodonium cation. In some embodiments, M+ can be a strontium cation having formula (2a) or an iodonium cation having formula (2b): (2a)(2b)

[0032] In formulas (2a) and (2b), R10, R20, and R30 can each independently be a substituted or unsubstituted C1-20 alkyl, a substituted or unsubstituted C3-20 cycloalkyl, a substituted or unsubstituted C2-20 alkenyl, a substituted or unsubstituted C6-30 aryl, a substituted or unsubstituted C6-30 iodoaryl, a substituted or unsubstituted C3-30 heteroaryl, a substituted or unsubstituted C7-20 arylalkyl, or a substituted or unsubstituted C4-20 heteroarylalkyl. Each of R10, R20, and R30 can be alone or linked to another group R10, R20, or R30 via a single bond or a divalent linker to form a ring. Each of R10, R20, and R30 may, as desired, include a divalent linker as part of its structure. Each of R10, R20, and R30 may independently contain, as needed, an acid-labile group selected from, for example, the following: a tertiary alkyl ester group, a secondary or tertiary aryl ester group, a secondary or tertiary ester group having a combination of alkyl and aryl groups, a tertiary alkoxy group, an acetal group, or a ketal group. Suitable divalent linking groups for connecting the R10, R20, and / or R30 groups include, for example, -O-, -S-, -Te-, -Se-, -C(O)-, -C(S)-, -C(Te)-, or -C(Se)-, substituted or unsubstituted C1-5 alkyl groups, or combinations thereof.

[0033] Exemplary strontium cations having formula (2a) include the following:

[0034] Exemplary iodine cations having formula (2b) include the following:

[0035] In some respects, photoactive compounds having formula (1a) can be represented by formula (3a): (3a)

[0036] In formula (3a), cyclo(CY1) can be a C3-30 carbocyclic group or a C3-30 heterocyclic group. Preferably, cyclo(CY1) is a C3-8 cycloalkyl group, a C6-14 aryl group, or a C3-12 heteroaryl group containing an aromatic ring heteroatom selected from nitrogen, oxygen, or combinations thereof.

[0037] In formula (3a), each L1 can independently be a single bond or a divalent linker.

[0038] In formula (3a), each R8 can independently be a hydroxyl group, -F, -I, -CF3, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl.

[0039] In equation (3a), a is an integer from 0 to 10. Preferably, a is an integer from 0 to 5, and typically a is an integer from 0 to 3.

[0040] In formula (3a), L2 is a single bond, -C(O)-, -C(O)O-, or -C(O)N(R5a)-, wherein R5a is hydrogen, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl.

[0041] In formula (3a), R9 can be hydrogen, cyano, hydroxyl, -F, -I, -CF3, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl. In some embodiments, when R9 is a substituted C1-10 alkyl, a substituted C3-20 cycloalkyl, a substituted C3-20 heterocycloalkyl, a substituted C6-10 aryl, or a substituted C3-10 heteroaryl, at least one substituent of the substituted R9 group can be hydroxyl, -I, or a combination thereof.

[0042] In equation (3a), M+ is the same as that defined in equation (1a).

[0043] In some respects, photoactive compounds having formula (1b) can be represented by formula (3b): (3b)

[0044] In formula (3b), the cyclic CY2 can be a C3-30 carbocyclic group or a C3-30 heterocyclic group. Preferably, the cyclic CY2 is a C3-8 cycloalkyl, a C6-14 aryl, or a C3-12 heteroaryl containing an aromatic cyclic heteroatom selected from nitrogen, oxygen, or combinations thereof.

[0045] In equation (3b), b is an integer from 0 to 10. Preferably, b is an integer from 0 to 5, and typically b is an integer from 0 to 3.

[0046] In formula (3b), L3 is a single bond, -C(O)-, -C(O)O-, or -C(O)N(R5b)-, wherein R5b is hydrogen, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl.

[0047] In formula (3b), R11 can be hydrogen, cyano, hydroxyl, -F, -I, -CF3, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl. In some embodiments, when R9 is a substituted C1-10 alkyl, substituted C3-20 cycloalkyl, substituted C3-20 heterocycloalkyl, substituted C6-10 aryl, or substituted C3-10 heteroaryl, at least one substituent of the substituted R9 group can be hydroxyl, -I, or a combination thereof.

[0048] In equation (3b), M+ is the same as that defined in equation (1b).

[0049] Non-limiting examples of the anionic moiety of a photoactive compound having formula (1a) may include one or more of the following compounds:

[0050] Non-limiting examples of the anionic moiety of a photoactive compound having formula (1b) may include one or more of the following compounds:

[0051] The present invention further relates to photoresist compositions comprising a photoactive compound and a solvent and may contain additional components as desired. Typically, the photoresist composition will further comprise a polymer, a photoacid generator (PAG), or a combination thereof.

[0052] According to one aspect, the photoresist composition further includes a material whose solubility in a base or organic solvent is altered by the action of an acid, wherein the material is different from the photoactive compound. For example, the material may be a polymer or a molecular glass.

[0053] The polymer may contain one or more repeating units. These repeating units may be one or more units for the purpose of, for example, adjusting the properties of the photoresist composition (such as etching rate and solubility). Exemplary repeating units may include those derived from one or more of (meth)acrylates, vinyl aromatics, vinyl ethers, vinyl ketones, and / or vinyl ester monomers.

[0054] In some embodiments, the polymer may comprise repeating units containing acid-labile groups. For example, repeating units containing acid-labile groups may be derived from one or more monomers having formulas (4), (5), or (6): (4)(5)(6)(7)(8)

[0055] In formulas (4), (5) and (6), Ra to Rc can each be independently hydrogen, fluorine, cyano, or a substituted or unsubstituted C1-10 alkyl group. Preferably, Ra to Rc can each be independently hydrogen, fluorine, or a substituted or unsubstituted C1-5 alkyl group, typically methyl.

[0056] In formula (4), L4 is a divalent linking group. For example, L4 may contain 1 to 10 carbon atoms and at least one heteroatom. In typical examples, L4 may be -OCH 2-, -OCH 2CH 2O-, or -N(R 5c)-, wherein R 5c is hydrogen or C 1-6 alkyl.

[0057] In formulas (4) and (5), R21 to R26 are each independently hydrogen, a substituted or unsubstituted C1-20 alkyl, a substituted or unsubstituted C3-20 cycloalkyl, a substituted or unsubstituted C3-20 heterocycloalkyl, a substituted or unsubstituted C2-20 alkenyl, a substituted or unsubstituted C3-20 cycloalkenyl, a substituted or unsubstituted C3-20 heterocycloalkenyl, a substituted or unsubstituted C6-20 aryl, or a substituted or unsubstituted C3-20 heteroaryl, provided that no more than one of R21 to R23 may be hydrogen and no more than one of R24 to R26 may be hydrogen, and provided that if one of R21 to R23 is hydrogen, then at least one of the others of R21 to R23 is a substituted or unsubstituted C6-20 aryl or a substituted or unsubstituted C6-20 aryl. The R21-R26 are 3-20 heteroaryl groups, and if one of R24 to R26 is a hydrogen group, then at least one of the others in R24 to R26 is a substituted or unsubstituted C6-20 aryl group or a substituted or unsubstituted C3-20 heteroaryl group. Preferably, each of R21 to R26 is independently a substituted or unsubstituted C1-6 alkyl group or a substituted or unsubstituted C3-10 cycloalkyl group. Each of R21 to R26 may further include a divalent linking group as part of its structure, if desired.

[0058] In formula (4), any two of R 21 to R 23 together may form a ring via a single bond or a divalent linking group, wherein the ring may be substituted or unsubstituted. In formula (5), any two of R 24 to R 26 together may form a ring via a single bond or a divalent linking group, wherein the ring may be substituted or unsubstituted.

[0059] For example, any one or more of R 21 to R 26 may independently be a group having the formula -CH 2C(=O)CH (3-n)Y n, wherein each Y is independently a substituted or unsubstituted C 2-10 heterocyclic alkyl group, and n is 1 or 2. For example, each Y may independently be a substituted or unsubstituted C 2-10 heterocyclic alkyl group including a group having the formula -O(Ca1)(Ca2)O-, wherein Ca1 and Ca2 are each independently hydrogenated or substituted or unsubstituted alkyl groups, and wherein Ca1 and Ca2 together form a ring as desired.

[0060] In formulas (6) and (8), R27, R28, R34 and R35 can each independently be hydrogen, a substituted or unsubstituted C1-20 alkyl, a substituted or unsubstituted C3-20 cycloalkyl, a substituted or unsubstituted C3-20 heterocyclic alkyl, a substituted or unsubstituted C6-20 aryl, or a substituted or unsubstituted C3-20 heteroaryl; and R16 and R22 are each independently a substituted or unsubstituted C1-20 alkyl, a substituted or unsubstituted C3-20 cycloalkyl, or a substituted or unsubstituted C3-20 heterocyclic alkyl. Preferably, R27, R28, R34 and R35 can each independently be hydrogen, a substituted or unsubstituted C1-20 alkyl, a substituted or unsubstituted C3-20 cycloalkyl, or a substituted or unsubstituted C3-20 heterocyclic alkyl. Each of R 27, R 28, R 34 and R 35 may, as needed, further include a divalent linker group as part of its structure.

[0061] In formula (7), R31 to R33 may each independently be a substituted or unsubstituted C1-20 alkyl, a substituted or unsubstituted C3-20 cycloalkyl, a substituted or unsubstituted C3-20 heterocycloalkyl, a substituted or unsubstituted C6-20 aryl, or a substituted or unsubstituted C3-20 heteroaryl, provided that no more than one of R31 to R33 may be hydrogen, and provided that if one of R31 to R33 is hydrogen, then at least one of the others of R31 to R33 is a substituted or unsubstituted C6-20 aryl or a substituted or unsubstituted C3-20 heteroaryl. Each of R31 to R33 may further include, as desired, a divalent linking group as part of its structure.

[0062] In formula (7), any two of R 31 to R 33 together form a ring as needed, which may further include a divalent linking group as part of its structure, wherein the ring group may be substituted or unsubstituted.

[0063] In formulas (7) and (8), Xa and Xb are each independently polymerizable groups containing olefinic unsaturated double bonds, such as substituted or unsubstituted C2-20 alkenyl or substituted or unsubstituted norcenyl, preferably (meth)acrylate or C2 alkenyl.

[0064] In formulas (7) and (8), L5 and L6 are each independently a single bond or a divalent linking group, provided that L5 is not a single bond when Xa is a C2-alkenyl and L6 is not a single bond when Xb is a C2-alkenyl. Preferably, L5 and L6 are each independently a substituted or unsubstituted C6-30 aryl or a substituted or unsubstituted C6-30 cycloalkyl. In formulas (7) and (8), n1 is 0 or 1, and n2 is 0 or 1. It should be understood that when n1 is 0, the L5 group is directly attached to an oxygen atom. It should be understood that when n2 is 0, the L6 group is directly attached to an oxygen atom.

[0065] In formula (8), any two of R 34 to R 36 together may form a ring as needed, wherein the ring may further include a divalent linking group as part of its structure, wherein the ring group may be substituted or unsubstituted.

[0066] In some aspects, each of R 21 to R 29 and R 31 to R 36 may further include, as needed, one or more divalent linking groups selected from -O-, -C(O)-, -C(O)O-, -S-, -S(O) 2-, -N(R')-, or -C(O)N(R')- as part of its structure, wherein R' may be hydrogen, a substituted or unsubstituted C 1-20 alkyl, a substituted or unsubstituted C 3-20 cycloalkyl, or a substituted or unsubstituted C 3-20 heterocycloalkyl.

[0067] In some aspects, in the repeating unit containing the acid-unstable group, the acid-unstable group may be a tertiary alkyl ester. For example, the repeating unit containing the tertiary alkyl ester group may be derived from one or more monomers having formula (4), (5), or (7), wherein R 21 to R 26 or R 34 to R 36 are not hydrogen, and n1 is a series 1.

[0068] An exemplary monomer having formula (4) includes one or more of the following:

[0069] An exemplary monomer having formula (5) includes one or more of the following: wherein Rd is as defined herein with respect to Rb in formula (3); and R' and R'' are each independently a substituted or unsubstituted C1-20 alkyl, a substituted or unsubstituted C3-20 cycloalkyl, a substituted or unsubstituted C3-20 heterocycloalkyl, a substituted or unsubstituted C2-20 alkenyl, a substituted or unsubstituted C3-20 cycloalkenyl, a substituted or unsubstituted C3-20 heterocycloalkenyl, a substituted or unsubstituted C6-20 aryl, or a substituted or unsubstituted C3-20 heteroaryl.

[0070] An exemplary monomer having formula (6) includes one or more of the following: wherein Rd is Rc as defined above.

[0071] An exemplary monomer having formula (7) includes one or more of the following:

[0072] An exemplary monomer having formula (8) includes one or more of the following:

[0073] In some aspects, the polymer may have an acid-instable repeating unit derived from one or more monomers having cyclic acetal or cyclic ketal groups, for example having one or more of the following structures: wherein Rd is Ra as defined above.

[0074] In some aspects, the polymer may have repeating units containing acid-labile groups (including tertiary alkoxy groups), such as one or more monomers of the following:

[0075] When present, repeating units containing acid-labile groups are typically included in the polymer in an amount of 5 to 95 mol%, more typically 20 to 80 mol%, and even more typically 30 to 50 mol%, based on the total repeating units in the polymer.

[0076] In some aspects, the polymer may further comprise repeating units containing polar groups, wherein the polar groups are laterally attached to the backbone of the polymer. For example, the polar groups may be lactone groups, hydroxyaryl groups, fluorool groups, or combinations thereof.

[0077] In one or more embodiments, the polymer may further comprise a third repeating unit derived from one or more lactone-containing monomers having formula (9): (9)

[0078] In formula (9), R f is hydrogen, fluorine, cyano, or substituted or unsubstituted C1-10 alkyl.

[0079] In formula (9), L7 is a single bond or a divalent linking group. Preferably, the L7 series single bond or one or more groups selected from the following: substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C1-30 heteroalkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocycloalkyl, substituted or unsubstituted C6-30 aryl, substituted or unsubstituted C3-30 heteroaryl, -O-, -C(O)-, -C(O)O-, -S-, -S(O)2-, -N(R')-, or -C(O)N(R'')-, wherein R' and R'' can each independently be hydrogen, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C3-20 cycloalkyl, or substituted or unsubstituted C3-20 heterocycloalkyl. When it is an L7-based single bond, the -R 37 part is directly attached to the oxygen atom adjacent to the carbonyl group (i.e., -C(O)OR 37).

[0080] In formula (9), R 37 is a substituted or unsubstituted group containing C 4-20 lactone, or a substituted or unsubstituted group containing C 4-20 sulfonyl lactone. The group containing C 4-20 lactone and the group containing C 4-20 sulfonyl lactone can be monocyclic, polycyclic or fused polycyclic.

[0081] An exemplary monomer having formula (9) may include one or more of the following: wherein R f is as defined for formula (9).

[0082] The polymer may contain repeating units that are alkali-soluble and / or have a pKa of less than or equal to 12. For example, repeating units containing polar groups side-attached to the polymer backbone may be derived from one or more monomers having formula (10), (11), or (12): (10)(11)(12)

[0083] In formula (10), (11) or (12), Rg to Rj can each be independently hydrogen, fluorine, cyano, or a substituted or unsubstituted C1-10 alkyl group. Preferably, Rg to Rj can each be independently hydrogen, fluorine, or a substituted or unsubstituted C1-5 alkyl group, typically methyl.

[0084] In formula (10), R 38 may be a substituted or unsubstituted C1-100 or C1-20 alkyl, typically C1-12 alkyl; a substituted or unsubstituted C3-30 or C3-20 cycloalkyl; or a substituted or unsubstituted poly(C1-3 epoxy). Preferably, the substituted C1-100 or C1-20 alkyl, the substituted C3-30 or C3-20 cycloalkyl, and the substituted poly(C1-3 epoxy) are substituted by one or more of the following: halogen, fluoroalkyl such as C1-4 fluoroalkyl (typically fluoromethyl), sulfonamide group -NH-S(O)2-Y1, wherein Y1 is an F or C1-4 perfluoroalkyl (e.g. -NHSO2CF3) or fluoroalcohol group (e.g. -C(CF3)2OH).

[0085] In formula (11), L8 represents a single bond or a polyvalent linking group selected from, for example, the following: an aliphatic group (such as a C1-6 alkyl or C3-20 cycloalkyl) to be substituted as desired, and an aromatic hydrocarbon, or combinations thereof, having one or more linking portions selected from -O-, -C(O)-, -C(O)O-, -S-, -S(O)2-, -NR102-, or -C(O)N(R102)-, wherein R102 is selected from hydrogen and a C1-10 alkyl to be substituted as desired. For example, the polymer may further comprise repeating units derived from one or more monomers having formula (10), wherein an L 8-series single bond or a multivalent linker selected from: substituted or unsubstituted C 1-20 alkyl groups, substituted or unsubstituted C 3-20 cycloalkyl groups, and substituted or unsubstituted C 6-24 aryl groups, typically substituted or unsubstituted C 1-6 alkyl groups, substituted or unsubstituted C 3-10 cycloalkyl groups, or substituted or unsubstituted C 6-24 aryl groups.

[0086] In formula (11), n3 is an integer from 1 to 5, typically 1. It should be understood that when n3 is 1, group L8 is a divalent linking group. It should be understood that when n3 is 2, group L8 is a trivalent linking group. Similarly, it should be understood that when n3 is 3, group L8 is a tetravalent linking group; when n3 is 4, group L8 is a pentavalent linking group; and when n3 is 5, group L8 is a hexavalent linking group. Therefore, in the context of formula (10), the term "multivalent linking group" refers to any one of divalent, trivalent, tetravalent, pentavalent, and / or hexavalent linking groups. In some respects, when n is 2 or greater, a carboxylic acid group (-C(O)OH) may be attached to the same atom of linking group L8. In other respects, when n is 2 or greater, a carboxylic acid group (-C(O)OH) may be attached to a different atom of linking group L8.

[0087] In formula (12), L9 represents a single bond or a divalent linking group. Preferably, L9 can be a single bond, a substituted or unsubstituted C6-30 aryl group, or a substituted or unsubstituted C6-30 cycloalkyl group.

[0088] In formula (12), n4 is 0 or 1. It should be understood that when n4 is 0, the part represented by -OC(O)- is a single bond, so that L9 is directly attached to the alkenyl (vinyl) carbon atom.

[0089] In formula (12), Ar1 is a substituted C5-60 aromatic group, which may include one or more aromatic cyclic heteroatoms selected from N, O, S, or combinations thereof, as needed, wherein the aromatic group may be monocyclic, non-fused polycyclic, or fused polycyclic. When the C5-60 aromatic group is polycyclic, the ring or cyclic group may be fused (e.g., naphthyl), non-fused, or a combination thereof. When the polycyclic C5-60 aromatic group is non-fused, the ring or cyclic group may be directly connected (e.g., biaryl, biphenyl, etc.) or may be bridged by heteroatoms (e.g., triphenylamino or diphenyl ether). In some aspects, the polycyclic C5-60 aromatic group may include a combination of a fused ring and a directly connected ring (e.g., naphthyl, etc.).

[0090] In equation (12), y can be an integer from 1 to 12, preferably from 1 to 6, and typically from 1 to 3. Each Rx can be hydrogen or methyl independently.

[0091] Non-limiting examples of monomers having formula (10), (11) or (12) include one or more of the following: wherein Y1 is as described above, and Ri is as defined in formulas (10)-(12).

[0092] When present, the polymer typically contains repeating units comprising polar groups (side-attached to the polymer backbone) in amounts of 1 to 60 mol%, typically 5 to 50 mol%, and more typically 5 to 40 mol%, based on the total repeating units in the polymer.

[0093] Non-limiting exemplary polymers of the present invention include one or more of the following: wherein each of x, y and z is a mole fraction of a related repeating unit, wherein the sum of the mole fractions of each polymer is 1.

[0094] The polymer can be prepared using any suitable method or one method in the art. For example, one or more monomers corresponding to the repeating unit herein can be fed together or separately using a suitable solvent or initiator and polymerized in a reactor. For example, the polymer can be obtained by polymerizing the respective monomers under any suitable conditions, such as by heating at an effective temperature, irradiation with photochemical radiation at an effective wavelength, or a combination thereof.

[0095] The photoresist composition also includes a photoacid generator (PAG). A suitable PAG generates an acid that causes the acid-indestructible groups present on the polymer of the photoresist composition to cleave during post-exposure baking (PEB). The PAG can be in a non-polymeric or polymeric form, for example, present in repeating units of polymers as described above, or as part of different polymers. A suitable non-polymeric PAG compound can have the formula G + A -, wherein G + is an organic cation selected from iodonium cations substituted with two alkyl groups, two aryl groups, or a combination of alkyl and aryl groups; and strontium cations substituted with three alkyl groups, three aryl groups, or a combination of alkyl and aryl groups; and A - is a non-polymeric organic anion. In some embodiments, PAG can be included as a non-polymeric PAG compound, as a repeating unit of a polymer having a PAG moiety derived from a polymerizable PAG monomer, or as a combination thereof.

[0096] Particularly suitable nonpolymeric organic anions include those whose conjugate acids have a pKa of -15 to 1. Particularly preferred anions are fluorinated alkyl sulfonates and fluorinated sulfonamides.

[0097] Useful non-polymerized PAG compounds are known in the field of chemically enhanced photoresists and include, for example: onium salts, such as triphenylstrontium trifluoromethane sulfonate, (p-tributoxyphenyl)diphenylstrontium trifluoromethane sulfonate, tri(p-tributoxyphenyl)strontium trifluoromethane sulfonate, triphenylstrontium p-toluene sulfonate; di- and tri-butylphenyl iodomonium perfluorobutane sulfonate and di- and tri-butylphenyl iodomonium camphor sulfonate. It is also known that nonionic sulfonates and sulfonyl compounds act as photoacid generators, such as nitrobenzyl derivatives, such as 2-nitrobenzyl-p-toluenesulfonate, 2,6-dinitrobenzyl-p-toluenesulfonate, and 2,4-dinitrobenzyl-p-toluenesulfonate; sulfonates, such as 1,2,3-tris(methanesulfonyloxy)benzene, 1,2,3-tris(trifluoromethanesulfonyloxy)benzene, and 1,2,3-tris(p-toluenesulfonyloxy)benzene; diazomethane derivatives, such as bis(benzenesulfonyl)diazomethane and bis(p-toluenesulfonyl)diazomethane; ethylene glycol Oxime derivatives, such as bis-O-(p-toluenesulfonyl)-α-dimethylglyoxime and bis-O-(n-butanesulfonyl)-α-dimethylglyoxime; sulfonate derivatives of N-hydroxyaceimine compounds, such as N-hydroxysuccinimine methanesulfonate and N-hydroxysuccinimine trifluoromethanesulfonate; and halogen-containing trihalomethane compounds, such as 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-trihalomethane and 2-(4-methoxynaphthyl)-4,6-bis(trichloromethyl)-1,3,5-trihalomethane. Suitable nonpolymeric photoacid generators are further described in U.S. Patent No. 8,431,325 to Hashimoto et al., in columns 37, lines 11-47 and 41-91. Other suitable sulfonate PAGs include sulfonated esters and sulfonylureas, nitrobenzyl esters, s-triazine derivatives, benzoin toluenesulfonate, α-(p-toluenesulfonylurea)acetic acid tributylphenyl ester, and α-(p-toluenesulfonylurea)acetic acid tributyl ester; as described in U.S. Patent Nos. 4,189,323 and 8,431,325.

[0098] Typically, when the photoresist composition contains a nonpolymeric photoacid generator, it is present in the photoresist composition in an amount of 1 to 65 wt% based on the total solids of the photoresist composition, more typically 2 to 20 wt%.

[0099] In some embodiments, G+ may be a strontium cation or an iodonium cation. For example, G+ may be a strontium cation as described herein with respect to M+, or G+ may be an iodonium cation as described herein with respect to M+. When the photoresist composition further comprises PAG, the cation G+ may be the same as M+, or the cation G+ may be different from M+.

[0100] PAGs that are onium salts typically contain organic anions with sulfonate groups or non-sulfonate groups, such as sulfonamidate, sulfonimidate, methylation, or borate.

[0101] Exemplary organic anions having a sulfonate group include the following:

[0102] Exemplary non-sulfonated anions include the following:

[0103] The photoresist composition may contain multiple PAGs as needed. The multiple PAGs may be polymeric, non-polymeric, or may include both polymeric and non-polymeric PAGs. Preferably, each of the multiple PAGs is non-polymeric.

[0104] In one or more aspects, the photoresist composition may include a first photoacid generator comprising a sulfonate group on an anion, and the photoresist composition may include a nonpolymerized second photoacid generator, wherein the second photoacid generator may include an anion without a sulfonate group.

[0105] In some aspects, the polymer may further include repeating units containing a PAG moiety, as desired. For example, repeating units derived from one or more monomers having formula (13): (13)

[0106] In formula (13), Rj can be hydrogen, fluorine, cyano, or a substituted or unsubstituted C1-10 alkyl group. Preferably, Rj is hydrogen, fluorine, or a substituted or unsubstituted C1-5 alkyl group, typically methyl. Q1 can be a single bond or a divalent linking group. Preferably, Q1 can contain 1 to 10 carbon atoms and at least one heteroatom, more preferably -C(O)-O-.

[0107] In formula (13), A1 can be one or more of the following: substituted or unsubstituted C1-30 alkylene, substituted or unsubstituted C3-30 cycloalkylene, substituted or unsubstituted C2-30 heterocycloalkylene, substituted or unsubstituted C6-30 arylene, or substituted or unsubstituted C3-30 heteroarylene. Preferably, A1 can be a divalent C1-30 perfluoroalkylene, substituted as needed.

[0108] In formula (13), Z- is the anionic moiety, whose conjugate acid typically has a pKa of -15 to 1. Z- can be a sulfonate, carboxylate, an anion of sulfonamide, an anion of sulfonimide, or a methyl anion. Particularly preferred anionic moiety is a fluorinated alkyl sulfonate or a fluorinated sulfonimide. G+ is an organic cation as defined above. In some embodiments, G+ is an iodonium cation substituted with two alkyl groups, two aryl groups, or a combination of alkyl and aryl groups; or a strontium cation substituted with three alkyl groups, three aryl groups, or a combination of alkyl and aryl groups.

[0109] Exemplary monomers having formula (13) may include the following: wherein G+ organic cations.

[0110] When included, the polymer may contain repeating units comprising the PAG portion in an amount of 1 to 15 mol%, typically 1 to 8 mol%, more typically 2 to 6 mol%, based on the total repeating units in the polymer.

[0111] The photoresist composition may contain a molecular glass compound. The molecular glass compound is a tetrameric calix[4]arene having free hydroxyl groups modified with acetal chemistry to contain an aromatic protecting group that is base-stable but acid-crackable, as provided in U.S. Patent No. 8,936,000 B2. The photoresist composition may contain a molecular glass compound in an amount of 50 to 99 wt%, preferably 55 to 95 wt%, more preferably 60 to 90 wt%, and even more preferably 65 to 90 wt% based on the total weight of solids. It will be understood that the term “molecular glass compound” as used in this context of the components in a photoresist may mean only the molecular glass compound, or a combination of the molecular glass compound with another molecular glass compound or polymer useful in the photoresist.

[0112] The photoresist composition further includes a solvent for dissolving the components of the composition and promoting its coating on a substrate. Preferably, the solvent is an organic solvent commonly 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, tributanol, 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-diethyl ether and anisole; ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, 2 - Heptanone and cyclohexanone (CHO); esters, such as ethyl acetate, n-butyl acetate, propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate (EL), methyl hydroxyisobutyrate (HBM), and ethyl acetoacetate; lactones, such as γ-butyrolactone (GBL) and ε-caprolactone; lactamines, such as N-methylpyrrolidone; nitriles, such as acetonitrile and propionitrile; cyclic or acyclic carbonates, such as propyl carbonate, dimethyl carbonate, ethyl carbonate, and diphenyl 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.

[0113] The total solvent content (i.e., the cumulative solvent content of all solvents) in the photoresist composition is based on the total solids of the photoresist composition, which is typically 40 to 99 wt%, for example 70 to 99 wt%, or 85 to 99 wt%. The desired solvent content will depend, for example, on the desired thickness of the coated photoresist layer and the coating conditions.

[0114] The polymer may typically be present in the photoresist composition in an amount of 10 to 99.9 wt%, typically 25 to 99 wt%, and more typically 50 to 95 wt% of the total solids based on the photoresist composition. It will be understood that "total solids" includes the photoactive compound, the polymer, PAG, and other non-solvent components.

[0115] In some aspects, the photoresist composition may further comprise a material containing one or more base-indestructible groups (“base-indestructible material”). As mentioned herein, the base-indestructible group can undergo a cleavage reaction in the presence of an aqueous base developer after the exposure step and the post-exposure baking step to provide functionality of polar groups (such as hydroxyl, carboxylic acid, sulfonic acid, etc.). The base-indestructible group will not react significantly before the development step of the photoresist composition containing the base-indestructible group (e.g., will not undergo bond breaking reactions). Therefore, for example, the base-indestructible group will be substantially inert during the pre-exposure soft baking step, the exposure step, and the post-exposure baking step. “Substantially inert” means that 5%, typically 1%, of the base-indestructible group (or a portion thereof) will decompose, cleave, or react during the pre-exposure soft baking step, the exposure step, and the post-exposure baking step. The base-indestructible group is reactive under typical photoresist development conditions using, for example, an aqueous base photoresist developer (such as an aqueous solution of 0.26 standard (N) tetramethylammonium hydroxide (TMAH)). For example, a 0.26 N aqueous solution of TMAH can be used for single-immersion development or dynamic development, where, for example, 0.26 N TMAH developer is dispensed onto the imaged photoresist layer for a suitable duration (e.g., 10 to 120 seconds). Exemplary base-insecure groups are ester groups, typically fluorinated ester groups. Preferably, the base-insecure material is substantially immiscible with the polymer and other solid components of the photoresist composition and has a lower surface energy than them. Thus, when coated onto a substrate, the base-insecure material can separate from the other solid components of the photoresist composition to reach the top surface of the formed photoresist layer.

[0116] In some aspects, the alkali-insecure material can be a polymeric material that may contain one or more repeating units containing one or more alkali-insecure groups (also referred to herein as an alkali-insecure polymer). For example, the alkali-insecure polymer may contain repeating units containing two or more identical or different alkali-insecure groups. Preferred alkali-insecure polymers contain at least one repeating unit containing two or more alkali-insecure groups, such as repeating units containing two or three alkali-insecure groups.

[0117] The alkali-unstable polymer may be a polymer comprising repeating units derived from one or more monomers having formula (14a): (14a) wherein the Xe series is selected from the polymerizable groups of: substituted or unsubstituted C2-20 alkenyl, or substituted or unsubstituted (meth)acrylyl, and the L10 series may include the following divalent linking groups: for example, substituted or unsubstituted C1-20 alkyl, substituted or unsubstituted C3-20 cycloalkyl, -C(O)- or -C(O)O-; and the Rn series is substituted or unsubstituted C1-20 fluoroalkyl, wherein the carbon atom bonded to the carbonyl (C=O) in formula (14a) is substituted with at least one fluorine atom.

[0118] An exemplary monomer having formula (14a) may include the following:

[0119] The base-insecure polymer may comprise repeating units containing two or more base-insecure groups. For example, the base-insecure polymer may comprise repeating units derived from one or more monomers having formula (14b): (14b) where Xf and Rp are as defined for Xe and Rn in formula (14a); L11 series includes one or more polyvalent linking groups selected from substituted or unsubstituted C1-20 alkyl groups, substituted or unsubstituted C3-20 cycloalkyl groups, -C(O)-, or -C(O)O-; and n4 series is an integer of 2 or larger, such as 2 or 3.

[0120] An exemplary monomer having formula (14b) may include the following:

[0121] The base-insecure polymer may comprise a repeating unit containing one or more base-insecure groups. For example, the base-insecure polymer may comprise a repeating unit derived from one or more monomers having formula (14c): (14c) where Xg and Rq are as defined for Xe and Rn in formula (14a); L12 is a divalent linking group; and L13 is a substituted or unsubstituted C1-20 fluoroalkyl group, wherein the carbon atom bonded to the carbonyl group (C=O) in formula (14c) is substituted with at least one fluorine atom.

[0122] An exemplary monomer having formula (14c) may include the following:

[0123] In another preferred aspect of the invention, the alkali-instable polymer may comprise one or more alkali-instable groups and one or more acid-instable groups, such as one or more acid-instable ester moieties (e.g., tributyl ester) or acid-instable acetal groups. For example, the alkali-instable polymer may comprise repeating units containing both alkali-instable and acid-instable groups, i.e., wherein both alkali-instable and acid-instable groups are present on the same repeating unit. In another example, the alkali-instable polymer may comprise a first repeating unit containing alkali-instable groups and a second repeating unit containing acid-instable groups. Preferred photoresists of the present invention can exhibit reduced defects associated with resist embossed images formed from photoresist compositions.

[0124] Base-insecure polymers can be prepared using any suitable method in the art, including those described herein with respect to the first and second polymers. For example, base-insecure polymers can be obtained by polymerization of the respective monomers under any suitable conditions, such as by heating at an effective temperature, irradiation with photochemical radiation at an effective wavelength, or a combination thereof. Alternatively or additionally, suitable methods can be used to graft one or more base-insecure groups onto the polymer backbone.

[0125] In some aspects, the alkali-instable material is a single molecule comprising one or more alkali-instable ester groups, preferably one or more fluorinated ester groups. A single-molecule alkali-instable material typically has a MW in the range of 50 to 1,500 Da. Exemplary alkali-instable materials include the following:

[0126] When present, the alkali-instable material typically exists in the photoresist composition in an amount of 0.01 to 10 wt% or 1 to 5 wt% of the total solids based on the photoresist composition.

[0127] In addition or alternatively, besides alkali-instable polymers, the photoresist composition may further include one or more polymers other than those described above. For example, the photoresist composition may contain additional polymers as described above but with different compositions, or polymers similar to those described above but not containing each of the required repeating units. In addition or alternatively, the one or more additional polymers may include those well known in the field of photoresists, such as those selected from: polyacrylates, polyvinyl ethers, polyesters, polynorcamphene, polyacetals, polyethylene glycol, polyamide, polyacrylamide, polyphenols, phenolic varnishes, styrene polymers, polyvinyl alcohol, or combinations thereof.

[0128] The photoresist composition may further include one or more additional optional additives. For example, optional additives may include photochemical dyes and contrast dyes, anti-stripping agents, plasticizers, accelerators, sensitizers, photodegradable quenchers (PDQ) (and also referred to as photodegradable bases), alkaline quenchers, hot acid generators, surfactants, etc., or combinations thereof. If present, optional additives are typically present in the photoresist composition in an amount of 0.01 to 10 wt% based on the total solids of the photoresist composition.

[0129] The PDQ generates a weak acid upon irradiation. The acid generated by the photodegradable quencher is not strong enough to react rapidly with the acid-instable groups present in the resist matrix. Exemplary photodegradable quenchers include, for example, photodegradable cations, and preferably those also used to prepare strong acid generating compounds, paired with anions of weak acids (pKa > 1) (e.g., anions of C1-20 carboxylic acids or C1-20 sulfonic acids). 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 photodegradable quencher is a photodegradable organic zwitterionic compound, such as diphenyliodonium-2-carboxylate.

[0130] The photodegradable quencher can be in non-polymeric or polymeric form. When in polymeric form, the photodegradable quencher is present in polymeric units on a first or second polymer. Polymeric units containing the photodegradable quencher are typically present in amounts of 0.1 to 30 mol%, typically 1 to 10 mol%, and more typically 1 to 2 mol%, based on the total repeating units in the polymer.

[0131] Exemplary alkaline quenchers include, for example: straight-chain aliphatic amines, such as tributylamine, trioctylamine, triisopropanolamine, tetra(2-hydroxypropyl)ethylenediamine, n-tert-butyldiethanolamine, tri(2-acetoxy-ethyl)amine, 2,2',2'',2'''-(ethane-1,2-diylbis(azanetriyl))tetraethanol, 2-(dibutylamino)ethanol, and 2,2',2''-nitrotriethanol; cyclic aliphatic... Amines, such as 1-(tributoxycarbonyl)-4-hydroxypiperidine, tributyl 1-pyrrolidinecarboxylate, tributyl 2-ethyl-1H-imidazolium-1-carboxylate, dibutyl-1,4-dicarboxylate, and N-(2-acetoxy-ethyl)oxoline; aromatic amines, such as pyridine, dibutylpyridine, and pyridinium; straight-chain and cyclic amides and their derivatives, such as N,N-bis(2-hydroxyethyl)palmitinylamine, N,N-diethylacetylamine, N... 1,N 1,N 3,N 3-Tetrabutylmalondiamine, 1-methylazacycloheptan-2-one, 1-allylazacycloheptan-2-one and tert-butyl 1,3-dihydroxy-2-(hydroxymethyl)propyl-2-ylaminocarbamate; ammonium salts, such as quaternary ammonium salts of sulfonates, aminosulfonates, carboxylates and phosphonates; imines, such as primary and secondary aldehyde imines and ketimines; diazoles, such as pyridines, piperazines and phenidines substituted as desired; diazoles, such as pyrazoles, thiadiazoles and imidazoles substituted as desired; and pyrrolidones substituted as desired, such as 2-pyrrolidone and cyclohexylpyrrolidone.

[0132] The alkaline quencher can be in non-polymeric or polymeric form. When in polymeric form, the quencher can be present in repeating units of the polymer. The repeating units containing the quencher are typically present in an amount of 0.1 to 30 mol% based on the total repeating units in the polymer, preferably 1 to 10 mol%, and more preferably 1 to 2 mol%.

[0133] Exemplary surfactants include fluorinated and nonfluorinated surfactants and may be ionic or nonionic, with nonionic surfactants being preferred. Exemplary fluorinated nonionic surfactants include perfluorinated C4 surfactants, such as FC-4430 and FC-4432 surfactants available from 3M Corporation; and fluorinated glycols, such as POLYFOX PF-636, PF-6320, PF-656, and PF-6520 fluorinated surfactants from Omnova. In this aspect, the photoresist composition further comprises a surfactant polymer containing fluorinated repeating units.

[0134] A method for patterning the photoresist composition of the present invention will now be described. Suitable substrates on 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, such as: semiconductor wafers; polycrystalline silicon substrates; packaging substrates, such as multi-chip modules; flat panel display substrates; substrates for light-emitting diodes (LEDs) including organic light-emitting diodes (OLEDs); etc., wherein semiconductor wafers are typical. Such substrates are typically composed of one or more of silicon, polycrystalline silicon, silicon oxide, silicon nitride, silicon oxynitride, silicon germanide, gallium arsenide, aluminum, sapphire, tungsten, titanium, titanium-tungsten, nickel, copper, and gold. Suitable substrates can be in the form of wafers, such as those used for manufacturing integrated circuits, optical sensors, flat panel displays, integrated optical circuits, and LEDs. Such substrates can be of any suitable size. Typical wafer substrate diameters are 200 to 300 millimeters (mm), although wafers with smaller and larger diameters can be suitably used according to the present invention. The substrate may include one or more layers or structures, which may include, as needed, the active or operable parts of the formed device.

[0135] Typically, prior to coating the photoresist composition of the present invention, one or more photolithographic layers, such as hard mask layers (e.g., spin-coated carbon (SOC), amorphous carbon, or metal hard mask layers), CVD layers (e.g., silicon nitride (SiN), silicon oxide (SiO), or silicon oxynitride (SiON) layers), organic or inorganic underlayers, or combinations thereof, are provided on the upper surface of the substrate. Such layers, together with the externally coated photoresist layers, form a photolithographic material stack.

[0136] If desired, an adhesion promoter layer may be applied to the substrate surface prior to coating the photoresist composition. If an adhesion promoter is desired, any suitable adhesion promoter for polymer films may be used, such as silanes, typically organosilanes like trimethoxyvinylsilane, triethoxyvinylsilane, hexamethyldisilazane, or aminosilane coupling agents like γ-aminopropyltriethoxysilane. Particularly suitable adhesion promoters include those sold from DuPont Electronics & Imaging (Marlborough, Massachusetts) under the names AP 3000, AP 8000, and AP 9000S.

[0137] The photoresist composition can be coated onto the substrate by any suitable method, including spin coating, spray coating, dip coating, blade coating, etc. For example, the application of the photoresist layer can be accomplished by spin coating the photoresist in a solvent using a coating track, wherein the photoresist is dispensed onto a rotating wafer. During the dispensing, the wafer is typically rotated at a speed of up to 4,000 rpm, for example, 200 to 3,000 rpm, for a period of 15 to 120 seconds to obtain a photoresist composition layer on the substrate. Those skilled in the art will understand that the thickness of the coated layer can be adjusted by changing the rotation speed and / or the total solids of the composition. The photoresist layer formed from the composition of the present invention typically has a dry layer thickness of 10 to 500 nanometers (nm), preferably 15 nm to 200 nm, and more preferably 20 nm to 120 nm.

[0138] Next, the photoresist composition is typically soft-baked to minimize the solvent content in the layer, thereby forming a non-stick coating and improving the adhesion of the layer to the substrate. Soft baking is performed, for example, on a heated plate or in an oven, where a heated plate is typical. The soft baking temperature and time will depend, for example, on the photoresist composition and thickness. Soft baking temperatures are typically 80°C to 170°C, and more typically 90°C to 150°C. Soft baking times are typically 10 seconds to 20 minutes, more typically 1 minute to 10 minutes, and even more typically 1 minute to 2 minutes. Those skilled in the art can easily determine the heating time based on the composition of the composition.

[0139] Next, the photoresist layer is exposed to activation radiation in a patterned manner to create a solubility difference between the exposed and unexposed areas. The exposure of the photoresist composition to radiation that activates the composition, as described herein, indicates that radiation can form a latent image in the photoresist composition. Exposure is typically performed using a patterned photomask having optically transparent and optically opaque regions corresponding to the areas of the resist layer to be exposed and the areas of the resist layer not being exposed, respectively. Alternatively, this exposure can be performed without a photomask in a direct-write method, typically used in electron beam lithography. The activation radiation typically has a wavelength less than 400 nm, less than 300 nm, or less than 200 nm, with wavelengths of 248 nm (KrF), 193 nm (ArF), 13.5 nm (EUV), or electron beam lithography being preferred. Preferably, the activation radiation is 193 nm radiation or EUV radiation. This method can be used in immersion or dry (non-immersion) photolithography. The exposure energy is typically 1 to 200 millijoules per square centimeter (mJ / cm²), preferably 10 to 100 mJ / cm², and even more preferably 20 to 50 mJ / cm², depending on the exposure tool and the composition of the photoresist.

[0140] After exposing the photoresist layer, post-exposure baking (PEB) of the exposed photoresist layer is performed. PEB can be performed, for example, on a heated plate or in an oven, with the heated plate being typical. The conditions of PEB will depend, for example, on the photoresist composition and layer thickness. PEB is typically performed at a temperature of 70°C to 150°C, preferably 75°C to 120°C, for a time of 30 to 120 seconds. A latent image defined by the polarity-converted region (exposed region) and the polarity-unconverted region (unexposed region) is formed in the photoresist.

[0141] The exposed photoresist layer is then developed with a suitable developer to selectively remove those areas of the layer that are soluble in the developer while retaining the insoluble areas, thereby forming the resulting photoresist pattern relief image. In the case of a positive development (PTD) process, the exposed areas of the photoresist layer are removed during development, and the unexposed areas are retained. Conversely, in a negative development (NTD) process, the exposed areas of the photoresist layer are retained during development, and the unexposed areas are removed. The application of the developer can be accomplished by any suitable method, as described above regarding the application of the photoresist composition, with spin coating being typical. The development time is the time period during which the soluble areas of the photoresist are effectively removed, typically 5 to 60 seconds. Development is typically performed at room temperature.

[0142] Suitable developers for PTD processes include aqueous alkaline developers, such as quaternary ammonium hydroxide solutions, such as tetramethylammonium hydroxide (TMAH) (preferably 0.26 standard (N) TMAH), tetraethylammonium hydroxide, tetrabutylammonium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc. Suitable developers for NTD processes are based on organic solvents, meaning that the cumulative content of organic solvents in the developer is 50 wt% or more, typically 95 wt% or more, 98 wt% or more, or 100 wt% 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. NTD developers are typically 2-heptanone or n-butyl acetate.

[0143] The coated substrate may be formed from the photoresist composition of the present invention. Such a coated substrate includes: (a) a substrate having one or more layers to be patterned on its surface; and (b) a photoresist composition layer on the one or more layers to be patterned.

[0144] Photoresist patterns can be used, for example, as an etching mask to transfer the pattern to one or more sequentially arranged underlying layers using known etching techniques, typically dry etching (such as reactive ion etching). The photoresist pattern can also be used, for example, to transfer a pattern to an underlying hard mask layer, which in turn serves as an etching mask for transferring the pattern to one or more layers below the hard mask layer. If the photoresist pattern is not lost during pattern transfer, it can be removed from the substrate using known techniques (such as oxygen plasma ashing). When used in one or more such patterning processes, photoresist compositions can be used to manufacture semiconductor devices such as memory devices, processor chips (CPUs), graphics chips, optoelectronic chips, LEDs, OLEDs, and other electronic devices.

[0145] The invention is further illustrated by the following examples. Examples of synthesis. The synthesis reactions were carried out under normal pressure. All chemicals were used as is, without further purification, from commercial suppliers. Synthesis of triphenylsulphine α-cyanocinolate (PAC1)

[0146] A solution was prepared by combining 5 g of α-cyanocinonic acid (28.87 mmol) and tetrahydrofuran (75 mL, THF). 1 g of LiOH in 15 mL of deionized (DI) water was added to the solution, and the resulting mixture was stirred at room temperature (approximately 25°C) for 1 hour. THF was then removed under reduced pressure to yield lithium α-cyanocinonicate. 50 mL of DI water, 75 mL of dichloromethane (DCM), and 9.9 g of triphenylstrontium bromide (28.87 mmol) were added to the lithium α-cyanocinonicate, and the mixture was stirred at room temperature (approximately 25°C) for 4 hours. The organic phase was then washed with DI water (5 × 50 mL). The organic phase was separated from the aqueous phase, and the solvent was removed under reduced pressure to yield the crude photoactive compound PAC1. The crude product was dissolved in 20 mL of acetone and this solution was poured into 150 mL of heptane to produce a colorless precipitate, PAC1. The precipitate was separated by filtration and dried to provide a colorless solid. The yield of PAC1 was 3.4 g (35%). Proton nuclear magnetic resonance spectroscopy (¹H-NMR) (in acetone-d6), chemical shift (δ, parts per million (ppm)): 8.10 (m, 7H), 7.80 (m, 11H, ArH), 7.40 (m, 3H). The purity of the superconducting liquid chromatography (UPLC) was 99.21%, as detected by ultraviolet (UV) absorbance at 210 nm. Synthesis of bis(4-(tributyl)phenyl)iodonium α-cyanocinonate (PAC2)

[0147] A solution was prepared by combining 10.0 g of α-cyanocinonic acid (57.74 mmol) and 150 mL of THF. 2 g of LiOH in 25 mL of DI water was added to the solution, and the resulting mixture was stirred at room temperature (approximately 25°C) for 1 hour. THF was then removed under reduced pressure to produce lithium α-cyanocinonate. 100 mL of DI water, 150 mL of DCM, and 24.8 g of bis(4-(tributyl)phenyl)acetic acid iodonium (54.82 mmol) were added to the lithium α-cyanocinonate, and the mixture was stirred at room temperature (approximately 25°C) for 4 hours. The organic phase was then washed with DI water (5 × 100 mL). The organic phase was separated from the aqueous phase, and the solvent was removed under reduced pressure to produce the crude photoactive compound PAC2. The crude product was dissolved in 40 mL of acetone, and this solution was poured into 300 mL of heptane to produce a colorless precipitate, PAC2. The precipitate was separated by filtration and dried to provide a colorless solid. The yield of PAC2 was 21.7 g (66.5%). ¹H NMR (in acetone-d6), δ (ppm): 7.89 (m, 4H, ArH), 7.78 (m, 3H, ArH), 7.38 (m, 7H), 1.21 (s, 18H, 6(CH3)). The UPLC purity was 99.30%, as detected by UV absorbance at 210 nm. Synthesis of bis(4-(tributyl)phenyl)iodonium-4-trifluoromethylcinnamate (PAC3)

[0148] A solution was prepared by combining 5.0 g of 4-trifluoromethylcinnamic acid (23.13 mmol) and 150 mL of THF. 0.8 g of LiOH in 25 mL of DI water was added to the solution, and the resulting mixture was stirred at room temperature (approximately 25°C) for 1 hour. THF was then removed under reduced pressure to produce lithium 4-trifluoromethylcinnamate. 100 mL of DI water, 150 mL of DCM, and 10.4 g of bis(4-(tributyl)phenyl)acetic acid iodonium (23.0 mmol) were added to the lithium 4-trifluoromethylcinnamate, and the mixture was stirred at room temperature (approximately 25°C) for 4 hours. The organic phase was then washed with DI water (5 × 50 mL). The organic phase was separated from the aqueous phase, and the solvent was removed under reduced pressure to produce the crude photoactive compound PAC3. The crude product was dissolved in 20 mL of acetone, and this solution was poured into 150 mL of heptane to produce a colorless precipitate, PAC3. The precipitate was separated by filtration and dried to provide a colorless solid. The yield of PAC3 was 8.9 g (63.5%). ¹H NMR (in acetone-d6), δ (ppm): 7.90 (d, 4H, ArH), 7.53 (d, 2H, ArH), 7.49 (d, 2H, ArH), 7.38 (d, 4H, ArH), 7.22 (d, 1H, CH=CH), 6.42 (d, 1H, CH=CH), 1.19 (s, 18H, 6(CH3)). The UPLC purity was 99.30%, as determined by UV absorbance at 210 nm. Synthesis of bis(4-(tert-butyl)phenyl)iodonium(Z)-3-fluoro-3-phenylacrylate (PAC4)

[0149] A solution was prepared by combining 1.0 g of α-fluorocinnamic acid (6.0 mmol) and 10 mL of THF. 0.2 g of LiOH in 5 mL of DI water was added to the solution, and the resulting mixture was stirred at room temperature (approximately 25°C) for 1 hour. THF was then removed under reduced pressure to produce lithium α-fluorocinnamate. 10 mL of DI water, 10 mL of DCM, and 2.0 g of bis(4-(tributyl)phenyl)acetic acid iodonium (4.42 mmol) were added to the lithium α-fluorocinnamate, and the mixture was stirred at room temperature (approximately 25°C) for 4 hours. The organic phase was then washed with DI water (5 × 15 mL). The organic phase was separated from the aqueous phase, and the solvent was removed under reduced pressure to produce a crude, optically active compound, PAC4, as a white solid. The crude product was suspended in 25 mL of heptane, separated by filtration, and dried to produce a white solid. The yield of PAC4 was 2.2 g (65.5%). ¹H NMR (in acetone-d6), δ (ppm): 8.12 (d, 4H, ArH), 7.50 (m, 6H, ArH), 7.33–7.26 (m, 3H, ArH), 6.50 (d, 1H, CH=CF), 1.20 (s, 18H, 6(CH₃)). UPLC purity was 99.92%, as determined by UV absorbance at 210 nm. Synthesis of bis(4-(tributyl)phenyl)iodonium(E)-3-cyclohexylacrylate (PAC5)

[0150] A solution was prepared by combining 1.0 g (E)-3-cyclohexylacrylic acid (6.48 mmol) and 10 mL THF. 0.15 g LiOH in 5 mL DI water was added to the solution, and the resulting mixture was stirred at room temperature (approximately 25°C) for 1 hour. THF was then removed under reduced pressure to produce lithium 3-cyclohexylacrylate. 10 mL DI water, 10 mL DCM, and 2.0 g bis(4-(tributyl)phenyl)acetic acid iodonium (4.42 mmol) were added to the lithium 3-cyclohexylacrylate, and the mixture was stirred at room temperature (approximately 25°C) for 4 hours. The organic phase was then washed with DI water (5 × 15 mL). The organic phase was separated from the aqueous phase, and the solvent was removed under reduced pressure to produce a crude, optically active compound, PAC5, as a white solid. The crude product was suspended in 25 mL heptane, separated by filtration, and dried to produce a white solid. The yield of PAC5 was 1.7 g (47.9%). ¹H NMR (in acetone-d6), δ (ppm): 7.83 (d, 4H, ArH), 7.39 (d, 4H, ArH), 6.51 (2H, CH=CH), 5.75 (d, 1H, CH=CH), 2–1.75 (6H, aliphatic-H), 1.19 (s, 18H, 6(CH3)), 1.18–1.08 (m. 5H aliphatic-H). UPLC purity was 99.66%, as determined by UV absorbance at 210 nm. Synthesis of bis(4-(tributyl)phenyl)iodonium(E)-3-(4-iodophenyl)acrylate (PAC6)

[0151] A solution was prepared by combining 1.0 g (E)-3-(4-iodophenyl)acrylic acid (3.65 mmol) and 10 mL THF. 0.15 g LiOH in 5 mL DI water was added to the solution, and the resulting mixture was stirred at room temperature (approximately 25°C) for 1 hour. THF was then removed under reduced pressure to produce lithium 3-cyclohexylacrylate. 10 mL DI water, 10 mL DCM, and 1.5 g bis(4-(tributyl)phenyl)acetic acid iodonium (3.32 mmol) were added to the lithium 3-cyclohexylacrylate, and the mixture was stirred at room temperature (approximately 25°C) for 4 hours. The organic phase was then washed with DI water (5 × 15 mL). The organic phase was separated from the aqueous phase, and the solvent was removed under reduced pressure to produce a crude, optically active compound, PAC6, as a white solid. The crude product was suspended in 25 mL heptane, separated by filtration, and dried to produce a white solid. The yield of PAC6 was 1.7 g (70.8%). ¹H NMR (in acetone-d6), δ (ppm): 8.06 (d, 4H, ArH), 7.67 (d, 2H, ArH), 7.46 (d, 4H, ArH), 7.26 (d, 2H, ArH), 6.93 (2H, CH=CH), 6.33 (d, 1H, CH=CH), 1.21 (s, 18H, 6(CH₃)). UPLC purity was 99.88%, as determined by UV absorbance at 210 nm. Synthesis of triphenylsulphine cinnamate (PAC7).

[0152] A solution was prepared by combining 10.0 g of cinnamic acid (67.49 mmol), 200 mL of acetone, and 200 mL of DI water, and then 7.0 g (30.2 mmol) of silver oxide was added to the solution in a small amount. The resulting mixture was stirred at room temperature (about 25°C) for 48 hours. The precipitate was separated by filtration, washed with acetone, and dried under reduced pressure. The yield of silver cinnamate was 13.5 g.

[0153] 5.0 g of silver cinnamate (5.0 g, 19.6 mmol) was dissolved in 150 mL of methanol and 30 mL of DI water to form a solution, and then 6.0 g of triphenylstrontium bromide (17.47 mmol) was added to the solution. The reaction mixture was stirred at room temperature (about 25°C) for 12 hours. 1H NMR of the reaction mixture showed that the desired cation to anion ratio of the product was 1:1. The mixture was filtered to remove undissolved salt and the solvent was removed under reduced pressure. The resulting residue was dissolved in acetone and filtered through a diatomaceous earth stopper. The solvent was removed from the filtrate under reduced pressure to produce PAC7 as a colorless oil. The yield of PAC7 was 1.7 g (70.8%). ¹H-NMR (in acetone-d6), δ (ppm): 8.08 (m, 6H, ArH), 7.88–7.78 (m, 9H, ArH), 7.41 (m, 2H), 7.27 (m, 2H, ArH), 7.20 (m, 2H, ArH), 6.50 (d, 1H, CH=CH). UPLC purity was 99.75%, as detected by UV absorbance at 210 nm. Synthesis of triphenylstrontium benzoate (CPAC8)

[0154] A solution was prepared by combining 5.0 g of benzoic acid (18.42 mmol), 100 mL of acetone, and 100 mL of DI water, and then 4.27 g (18.42 mmol) of silver oxide was added to the solution in a small fraction. The resulting mixture was stirred at room temperature (about 25°C) for 48 hours. The precipitate was separated by filtration, washed with acetone, and dried under reduced pressure. The yield of silver benzoate was 7.3 g.

[0155] 2.5 g of silver benzoate (10.9 mmol) was dissolved in 100 mL of methanol and 20 mL of DI water to form a solution, and then 2.5 g of triphenylstrontium bromide (7.28 mmol) was added to the solution. The reaction mixture was stirred at room temperature (about 25°C) for 12 hours. 1H-NMR of the reaction mixture showed that the desired cation to anion ratio of the product was 1:1. The mixture was filtered to remove undissolved salt and the solvent was removed under reduced pressure. The resulting residue was dissolved in acetone and filtered through a diatomaceous earth stopper. The solvent was removed from the filtrate under reduced pressure to produce CPAC8, a colorless oil. The UPLC purity was 99.63%, as detected by UV absorbance at 210 nm. Synthesis of Triphenylstrontium (E)-3-(Thiophene-3-yl)acrylate (CPAC9)

[0156] A solution was prepared by combining 2.55 g of (E)-3-(thiophen-3-yl)acrylic acid (16.2 mmol), 50 mL of acetone, and 50 mL of DI water, and then 1.80 g (7.76 mmol) of silver oxide was added to the solution in a small fraction. The resulting mixture was stirred at room temperature (about 25°C) for 48 hours. The precipitate was separated by filtration, washed with acetone, and then dried under reduced pressure. The yield of silver (E)-3-(thiophen-3-yl)acrylate was 3.30 g.

[0157] 3.30 g of (E)-3-(thiophene-3-yl)silver acrylate (10.9 mmol) was dissolved in 100 mL of methanol and 20 mL of DI water to form a solution, and then 3.48 g of triphenylstrontium bromide (10.0 mmol) was added to the solution. The reaction mixture was stirred at room temperature (about 25°C) for 12 hours. 1H-NMR analysis of the reaction mixture showed that the desired cation to anion ratio of the product was 1:1. The mixture was filtered to remove undissolved salts and then the solvent was removed under reduced pressure. The resulting residue was dissolved in acetone and filtered through a diatomaceous earth stopper. The solvent was removed from the filtrate under reduced pressure to produce CPAC9, a colorless oil. The UPLC purity was 99.64%, as detected by UV absorbance at 210 nm. Photoresist Formulation 1. The photoresist composition was prepared by dissolving the solid components in a solvent to a total solids content of 2.6 wt% using the materials and amounts listed in Table 1. Each mixture was vibrated using a mechanical vibrator and filtered through a PTFE disc filter with a pore size of 0.2 µm. The amounts of polymers, PAGs, and photoactive compounds were reported as wt% of the total solids of the photoresist composition. The solvent system contained propylene glycol monomethyl ether acetate (PGMEA) (50 wt%) and methyl 2-hydroxyisobutyrate (50 wt%). Photolithography Evaluation 1. Photolithography was performed using a CLEAN TRACK ACT8 (TEL, Tokyo Electron Co.) wafer track. A 200 nm wafer used for photolithography testing was coated with AR™3 BARC (DuPont Electronics & Industrial) and soft-baked at 205°C for 60 seconds to obtain a 60 nm film. The AR™40 BARC (DuPont Electronics & Industries) coating was then deposited on the AR™3 layer and soft-baked at 205°C for 60 seconds to form a second BARC layer with a thickness of 80 nm. The photoresist composition was then coated onto the double BARC stack and soft-baked at 110°C for 60 seconds to obtain a photoresist film layer with a thickness of 70 nm. The wafer was exposed to 248 nm radiation using a mask with a 1:1 line-space (L / S) pattern (120 nm linewidth) on a Canon FPA-5000 ES4 scanner (NA = 0.8, outer sigma = 0.85, inner sigma = 0.57). The exposed wafer was then baked at 100°C for 60 seconds, developed with 0.26 N TMAH solution for 60 seconds, rinsed with DI water, and spin-dried to form the photoresist pattern. The critical dimension (CD) linewidth of the formed pattern was measured using a HITACHI S-9380 CD-SEM.Line width roughness (LWR) is determined by the deviation of the width of a line measured over a given length, and is evaluated using a 3-sigma (3σ) deviation of the width from a distribution of a total of 100 arbitrary line width measurement points. LWR data are shown in Table 1. [Table 1] Example polymer PAG Photoactive compounds LWR (nm) 1 P1 (79.18) PAG 1 (16.56) PAC1 (4.26) 7.75 2 P1 (78.19) PAG 1 (16.35) PAC2 (5.46) 6.82 3 P1 (77.87) PAG 1 (16.28) PAC3 (5.85) 7.93 4* P1 (80.05) PAG 1 (16.75) Q1 (3.20) 8.22 *Indicates a comparative example. Photoresist Formulation 2. The photoresist composition was prepared by dissolving the solid components in a solvent to a total solids content of 4.2 wt% using the materials and amounts listed in Table 2. Each mixture was vibrated using a mechanical vibrator and then filtered through a PTFE disc filter with a pore size of 0.2 µm. The amounts of polymers, PAGs, and photoactive compounds were reported as wt% of the total solids of the photoresist composition. The solvent system contained PGMEA (50 wt%) and methyl 2-hydroxyisobutyrate (50 wt%). Photolithography Evaluation 2. Photolithography was performed using a CLEAN TRAC ACT8 (TEL, Tokyo Electron Ltd.) wafer track. A 200 nm wafer used for photolithography testing was coated with AR™3 BARC (DuPont Electronics & Industrial) and soft-baked at 205°C for 60 seconds to obtain a 60 nm film. The AR™40A BARC (DuPont Electronics & Industries) coating was then deposited on the AR™3 layer and soft-baked at 2050°C for 60 seconds to form a second BARC layer with a thickness of 80 nm. The photoresist composition was then coated on the double BARC stack and soft-baked at 110°C for 60 seconds to obtain a photoresist film layer with a thickness of 120 nm.

[0158] The wafer was exposed to 248 nm radiation using a mask with a 1:1 L / S pattern (120 nm linewidth) on a CANON FPA-5000 ES4 scanner (NA = 0.8, outer sigma = 0.85, inner sigma = 0.57). The exposed wafer was then baked at 100°C for 60 seconds, developed with 0.26 N TMAH solution for 60 seconds, rinsed with DI water, and spin-dried to form the photoresist pattern. The CD linewidth of the formed pattern was measured using a HITACHI S-9380 CD-SEM. The LWR was determined by the deviation of the linewidth measured over a given length and evaluated using the 3σ deviation of the width from a distribution of a total of 100 arbitrary linewidth measurement points. The LWR data are shown in Table 2. [Table 2] Photoresist composition polymer Photoacid generator Photoactive compounds LWR (nm) 5 P2 (77.47) PAG 1 (19.37) PAC1 (3.16) 6.98 6 P2 (76.75) PAGE 1 (19.19) PAC2 (4.06) 6.47 7 P2 (76.89) PAGE 1 (19.22%) PAC3 (3.89) 7.20 8 P2 (76.78) PAGE 1 (19.20) PAC4 (4.02) 6.70 9 P2 (76.85) PAGE 1 (19.21) PAC5 (3.94) 7.03 10 P2 (76.19) PAGE 1 (19.05) PAC6 (4.76) 7.35 11 P2 (77.61) PAGE 1 (19.40) PAC7 (2.99) 7.33 12* P2 (77.76) PAG1 (19.44) CPAC8 (2.89) 8.09 *Indicates a comparative example. Photoresist Formulation 3. The photoresist composition was prepared by dissolving the solid components in a solvent to achieve a total solids content of 1.55 wt% using the materials and amounts listed in Table 3. Each mixture was vibrated using a mechanical vibrator and filtered through a PTFE disc filter with a pore size of 0.2 µm. The amounts of polymers, PAGs, and photoactive compounds were reported as wt% of the total solids of the photoresist composition. The solvent system contained PGMEA (50 wt%) and methyl 2-hydroxyisobutyrate (50 wt%). Photolithography Evaluation 3. Photolithography was performed using a CLEAN TRAC ACT8 (TEL, Tokyo Electron Ltd.) wafer track. A 300 nm wafer used for photolithography testing was coated with an organic BARC film to obtain a 60 nm film, and then a silicon-containing antireflective coating (SiARC) film was deposited on the organic BARC film to form a second layer with a thickness of 20 nm. The photoresist composition was then spin-coated onto a BARC / SiARC bilayer stack and soft-baked at 110°C for 60 seconds to obtain a photoresist film with a thickness of 40 nm.

[0159] Using an ASML NXE3400B scanner, the wafer was exposed to 13.5 nm radiation using a mask with a CD of 20.25 nm and a trench pattern with a 36-pitch spacing. The exposed wafer was then baked at 100°C for 60 seconds, developed with 0.26 N TMAH solution for 60 seconds, rinsed with DI water, and spin-dried to form the resist trench pattern. The CD linewidth of the formed trench pattern was measured using a HITACHI CG5000 CD-SEM.

[0160] Table 3 shows the EUV sizing energy (E-size) determined for the examples, which is the irradiation energy when the trench pattern is resolved to 18 nm and reported in millijoules per square centimeter (mJ / cm²). Table 3 also shows the depth of focus (DOF) of the examples, which is the total focusing distance range that maintains the printed features without any printing defects. [Table 3] Example polymer PAG Photoactive compound E 尺寸 (mJ / cm) 2 ) DOF (nm) 13 P2 (75.87) PAG 1 (18.97) PAC1 (5.16) 36 60 14 P2 (74.72) PAGE 1 (18.68) PAC2 (6.60) 33.8 > 80 15 P2 (74.95) PAGE 1 (18.74) PAC3 (6.31) 28.2 > 80 16 P2 (74.78) PAGE 1 (18.70) PAC4 (6.52) 31.0 80 17 P2 (74.88) PAGE 1 (18.72) PAC5 (6.40) 28.0 > 100 18 P2 (73.85) PAGE 1 (18.46) PAC6 (7.69) 30.8 > 100 19* P2 (76.04) PAG1 (19.01) CPAC8 (4.95) 30.8 40 20* P2 (76.33) PAG1 (19.08) CPAC8 (4.59) 25.4 40 * indicates a comparison instance.

[0161] As demonstrated by the results in comparisons of Tables 1, 2, and 3, the photoactive compounds of the present invention provide photoresist compositions with unexpected photolithographic properties and achieve a reduction in LWR of up to 20%. It was observed that the improvement in LWR had no effect on photosensitivity and improved DOF.

[0162] Although this disclosure has been described in conjunction with exemplary embodiments now considered to be practical, it should be understood that the invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. [Simplified Explanation of the Diagram]

[0009] None

Claims

1. A photoactive compound having formula (1a) or (1b): (1a) (1b) wherein, R1 series: substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocycloalkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl containing an aromatic ring heteroatom selected from nitrogen, oxygen, or combinations thereof; R2 series: hydrogen, halogen, substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C1-30 heteroalkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocycloalkyl, substituted or unsubstituted C2-30 alkenyl, substituted or unsubstituted C2-30 alkoxy, substituted or unsubstituted C1-C30 alkylthio, substituted or unsubstituted C3-C10 cycloalkenyl, substituted or unsubstituted C3-C 10. Heterocyclic alkenyl, substituted or unsubstituted C6-30 aryl, substituted or unsubstituted C7-30 arylalkyl, substituted or unsubstituted C7-30 alkylaryl, or substituted or unsubstituted C6-C30 aryloxy; R3 is a hydrogen or non-hydrogen substituent; R4 is a substituted or unsubstituted C1-30 alkyl, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C3-30 heterocyclic alkyl, substituted or unsubstituted C6-30 aryl, or substituted or unsubstituted C3-30 heteroaryl; Each of R2, R3 and R4 may further include, as desired, one or more divalent linking groups as part of its structure, wherein each of the one or more divalent linking groups is independently substituted or unsubstituted; R2 and R 3. It is required to form a ring, which is required to further include one or more divalent linking groups as part of its structure, wherein each of the one or more divalent linking groups is substituted or unsubstituted, and wherein the ring is substituted or unsubstituted; and M+ is an organic cation.

2. The photoactive compound as described in claim 1, wherein, R3 series substituted or unsubstituted C1-20 organic groups.

3. The photoactive compound as described in claim 2, wherein, R3 further includes -C(O)-, -C(O)O-, -C(O)N(R5)-, or combinations thereof, and R5 is hydrogen, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl.

4. The photoactive compound as described in claim 1, wherein, R is a 3-series halogen atom, cyano group, or C1-5 haloalkyl group.

5. The photoactive compound as described in claim 1, wherein, R1 series substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-20 aryl, or substituted or unsubstituted C3-20 heteroaryl containing an aromatic cyclic heteroatom selected from nitrogen or oxygen.

6. The photoactive compound as claimed in claim 1, wherein, R4 series substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-20 aryl, or substituted or unsubstituted C3-20 heteroaryl.

7. The photoactive compound as described in claim 1, wherein, M+ series strontium cations or iodonium cations.

8. A photoresist composition comprising: a photoactive compound as described in claim 1; and a solvent.

9. The photoresist composition as claimed in claim 8, further comprising a material whose solubility in an alkali or organic solvent is altered by the action of an acid, wherein the material is different from the photoactive compound.

10. The photoresist composition as claimed in claim 9, further comprising a photoacid generator different from the photoactive compound.

11. A method for forming a pattern, the method comprising: (a) A photoresist layer is formed on a substrate using the photoresist composition as described in claim 8; (b) Expose the photoresist layer to activation radiation in a patterned manner; and (c) Develop the exposed photoresist layer to provide a resist relief image.

12. The photoresist composition as described in claim 8, wherein, R3 series substituted or unsubstituted C1-20 organic groups.

13. The photoresist composition as described in claim 8, wherein, R3 further includes -C(O)-, -C(O)O-, -C(O)N(R5)-, or combinations thereof, and R5 is hydrogen, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl.

14. The photoresist composition as described in claim 8, wherein, R is a 3-series halogen atom, cyano group, or C1-5 haloalkyl group.

15. The photoresist composition as described in claim 8, wherein, R1 series substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-20 aryl, or substituted or unsubstituted C3-20 heteroaryl containing an aromatic cyclic heteroatom selected from nitrogen or oxygen.

16. The photoresist composition as described in claim 8, wherein, R4 series substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-20 aryl, or substituted or unsubstituted C3-20 heteroaryl.

17. The photoresist composition as described in claim 8, wherein, R4 series substituted or unsubstituted C3-20 cycloalkyl, substituted or unsubstituted C3-20 heterocycloalkyl, substituted or unsubstituted C6-20 aryl, or substituted or unsubstituted C3-20 heteroaryl.

18. The photoresist composition as described in claim 8, wherein, M+ series strontium cations or iodonium cations.

19. The method as described in claim 11, wherein, R3 series substituted or unsubstituted C1-20 organic groups.

20. The method as described in claim 11, wherein, R3 further includes -C(O)-, -C(O)O-, -C(O)N(R5)-, or combinations thereof, and R5 is hydrogen, substituted or unsubstituted C1-10 alkyl, substituted or unsubstituted C1-10 heteroalkyl, substituted or unsubstituted C6-10 aryl, or substituted or unsubstituted C3-10 heteroaryl.