An onium salt monomer containing an aromatic sulfonic acid anion having a vinyl-substituted aromatic ring is provided as well as a polymer comprising repeat units derived from the monomer. A chemically amplified resist composition comprising the polymer has advantages including high sensitivity, high contrast, improved lithography properties, e.g., EL, LWR, CDU and DOF, collapse resistance during fine pattern formation, and etch resistance after development.

A method for functionalization of an aromatic amino acid or a nucleobase with a fluoroalkyl-containing moiety RF, wherein the aromatic amino acid is reacted in the presence of at least one reductant with at least one hypervalent iodine fluoroalkyl reagent carrying the fluoroalkyl-containing moiety RF is disclosed. Novel hypervalent iodine fluoroalkyl reagents is also disclosed.

A method for functionalization of an aromatic amino acid or a nucleobase with a fluoroalkyl-containing moiety RF, wherein the aromatic amino acid is reacted in the presence of at least one reductant with at least one hypervalent iodine fluoroalkyl reagent carrying the fluoroalkyl-containing moiety RF is disclosed. Novel hypervalent iodine fluoroalkyl reagents is also disclosed.

Provided is a method of producing an anhydride of an organic mono-acid comprising contacting an organic mono-acid and a thermally regenerable anhydride to produce the anhydride of the organic mono-acid, and either a diacid of the regenerable anhydride, a partially hydrolyzed regenerable anhydride, or both. In a particular example, acetic acid and glutaric anhydride can be reacted to form acetic anhydride.

Provided is a method of producing an anhydride of an organic mono-acid comprising contacting an organic mono-acid and a thermally regenerable anhydride to produce the anhydride of the organic mono-acid, and either a diacid of the regenerable anhydride, a partially hydrolyzed regenerable anhydride, or both. In a particular example, acetic acid and glutaric anhydride can be reacted to form acetic anhydride.

An onium salt containing a sulfonic acid anion having a substituted fused ring structure and an aromatic sulfonic acid structure is provided. A chemically amplified resist composition comprising the onium salt has satisfactory solvent solubility, high sensitivity, and high contrast, and forms a resist film with improved lithography properties such as EL and LWR.

An onium salt containing a sulfonic acid anion having a substituted fused ring structure and an aromatic sulfonic acid structure is provided. A chemically amplified resist composition comprising the onium salt has satisfactory solvent solubility, high sensitivity, and high contrast, and forms a resist film with improved lithography properties such as EL and LWR.

A radiation-sensitive composition includes: an onium salt compound represented by formula (1); a polymer including a structural unit (I) which includes an acid-dissociable group; and a solvent. W is a cyclic structure having 3 to 40 ring members formed together with the two carbon atoms; a formula between the two carbon atoms below represents a single bond or a double bond, , A is one of groups represented by formulae (A-1) to (A-7); R.sup.1 is a monovalent organic group having 1 to 20 carbon atoms, a cyano group, a nitro group, a carboxy group, a hydroxy group, an amino group, a halogen atom, or a thiol group, when there are a plurality of R.sup.1s, the plurality of R.sup.1s are same as or different from each other; m.sub.1 is an integer of 0 to 4; and Z.sup.+ is a monovalent radiation-sensitive onium cation.

##STR00001##

A radiation-sensitive composition includes: an onium salt compound represented by formula (1); a polymer including a structural unit (I) which includes an acid-dissociable group; and a solvent. W is a cyclic structure having 3 to 40 ring members formed together with the two carbon atoms; a formula between the two carbon atoms below represents a single bond or a double bond, , A is one of groups represented by formulae (A-1) to (A-7); R.sup.1 is a monovalent organic group having 1 to 20 carbon atoms, a cyano group, a nitro group, a carboxy group, a hydroxy group, an amino group, a halogen atom, or a thiol group, when there are a plurality of R.sup.1s, the plurality of R.sup.1s are same as or different from each other; m.sub.1 is an integer of 0 to 4; and Z.sup.+ is a monovalent radiation-sensitive onium cation.

##STR00001##