Actinic-ray- or radiation-sensitive resin composition, actinic-ray- or radiation-sensitive film therefrom and method of forming pattern using the composition

An actinic-ray- or radiation-sensitive resin composition comprising:

• (A) a resin to be decomposed to increase its solubility in an alkali developer when acted on by an acid, and
• (B) a monovalent ionic compound represented by the general formula (1-1) below,
• where
• A represents a sulfur atom or an iodine atom,
• R1 each independently represents an alkyl group, an alkenyl group, a cycloaliphatic group, an aromatic hydrocarbon group or a heterocyclic hydrocarbon group;
• when m is 2, two R1s are both alkyl groups or both aryl groups, and two R1s may be bonded to each other to form a ring,
• Ar each independently represents an aromatic ring group,
• X each independently represents a bivalent connecting group,
• R2 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloaliphatic group, an aromatic hydrocarbon group or a heterocyclic hydrocarbon group,
• at least two groups selected from X and two R2s may be bonded to each other to form a ring, and
• provided that to the nitrogen atom (N) in the general formula (1-1), at least one group is directly bonded, the group being selected from a cycloaliphatic group, an aromatic hydrocarbon group, a heterocyclic hydrocarbon group and a chain aliphatic group whose moiety adjacent to the nitrogen atom is a tertiary or quaternary carbon atom, and an electron withdrawing group selected from a carbonyl group, a sulfonyl group, a cyano group and a halogen atom is not directly bonded,
• when A is a sulfur atom, n is an integer of 1 to 3, and m is an integer satisfying the relationship m+n=3,
• when A is an iodine atom, n is an integer of 1 or 2, and m is an integer satisfying the relationship m+n=2,
• o is an integer of 1 to 10, and
• Y− represents a non-nucleophilic anion.