Radiation-sensitive resin composition, resist pattern-forming method, acid diffusion control agent, carboxylic acid salt and carboxylic acid

An acid diffusion control agent of formula (1′),

• wherein X is an oxygen atom or a sulfur atom;
• R1 is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms;
• R2 and R3 are each independently a hydrogen atom, a hydrocarbon group, a hydroxy group-substituted hydrocarbon group, a hydroxy group- and a fluorine atom-substituted hydrocarbon group, or a group comprising an aliphatic heterocyclic structure, or R2 and R3 taken together an alicyclic structure having 3 to 20 ring atoms or an aliphatic heterocyclic structure having 3 to 20 ring atoms together with the carbon atom to which R2 and R3 bond;
• R4 and R5 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and optionally R4 and R5 taken together are an alicyclic structure having 3 to 20 ring atoms or an aliphatic heterocyclic structure having 3 to 20 ring atoms together with the carbon atom to which R4 and R5 bond;
• Zn+ is a radiation-sensitive cation having a valency of n;
• and n is an integer of 1 to 3.

A carboxylic acid salt of formula (i),

• wherein X is an oxygen atom or a sulfur atom;
• R1 is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms;
• R2 and R3 are each independently a hydrogen atom, a hydrocarbon group, a hydroxy group-substituted hydrocarbon group, a hydroxy group- and a fluorine atom-substituted hydrocarbon group, or a group comprising an aliphatic heterocyclic structure, or R2 and R3 taken together an alicyclic structure having 3 to 20 ring atoms or an aliphatic heterocyclic structure having 3 to 20 ring atoms together with the carbon atom to which R2 and R3 bond:
• R4 and R5 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and optionally R4 and R5 taken together represent are an alicyclic structure having 3 to 20 ring atoms or an aliphatic heterocyclic structure having 3 to 20 ring atoms together with the carbon atom to which R4 and R5 bond;
• Zn+ is a radiation-sensitive cation having a valency of n;
• and n is an integer of 1 to 3.

A carboxylic acid of formula (i′),

• wherein X is an oxygen atom or a sulfur atom;
• R1 is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms;
• R2 and R3 are each independently a hydrogen atom, a hydrocarbon group, a hydroxy group-substituted hydrocarbon group, a hydroxy group- and a fluorine atom-substituted hydrocarbon group, or a group comprising an aliphatic heterocyclic structure, or R2 and R3 taken together an alicyclic structure having 3 to 20 ring atoms or an aliphatic heterocyclic structure having 3 to 20 ring atoms together with the carbon atom to which R2 and R3 bond;
• and R4 and R5 are each independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, and optionally R4 and R5 taken together are an alicyclic structure having 3 to 20 ring atoms or an aliphatic heterocyclic structure having 3 to 20 ring atoms together with the carbon atom to which R4 and R5 bond.