NOVELTY - Actinic-ray- or radiation-sensitive resin composition comprises resin that when acted on by acid, is decomposed to increase its solubility in an alkali developer, and a aryl compound that when exposed to actinic rays or radiation, is decomposed to generate an acid.    USE - The composition is useful for forming an actinic-ray- or radiation-sensitive film and forming pattern and in semiconductor production process (all claimed) for an integrated circuit, a circuit board production process for a liquid crystal, a thermal head and other photofabrication lithography processes.    ADVANTAGE - The composition exhibits excellent in sensitivity, roughness characteristics and exposure latitude.    DETAILED DESCRIPTION - Actinic-ray- or radiation-sensitive resin composition comprises: a resin that when acted on by an acid, is decomposed to increase its solubility in an alkali developer; and a compound that when exposed to actinic rays or radiation, is decomposed to generate an acid, where the aryl compound has a structure of formula ((R1)m-A+-(Ar1-(X-AN)o)n Y1-) (I).    A = sulfur atom or iodine atom;    R1 = alkyl, alkenyl, cycloaliphatic, aromatic hydrocarbon or heterocyclic hydrocarbon (when m=2);    Ar1 = aryl ring (when n greater than or equal to 2);    X = connecting group having a carbon atom to which Ar1 is bonded (when o greater than or equal to 2 and/or n greater than or equal to 2);    AN = basic moiety containing N atom (when o greater than or equal to 2 and/or n greater than or equal to 2); either    n = 1-3 and m is satisfying the relationship m+n=3 when A is a sulfur atom; or    n = 1 or 2 and m is an integer satisfying the relationship m+n=2 when A is an iodine atom;    o = 1-10; and    Y1- = anion.    Provided that when m=2, two R1s may be bonded to each other to form a ring. INDEPENDENT CLAIMS are included for:    (1) forming a pattern, comprising forming the composition into a film, exposing the film to light, and developing the exposed film;    (2) manufacturing a semiconductor device, comprising the pattern forming method; and    (3) the semiconductor device manufactured by the process.