The actinic ray-sensitive or radiation-sensitive resin composition and pattern forming method using the same

PROBLEM TO BE SOLVED: To provide an active light sensitive or a radiation sensitive resin composition which simultaneously satisfies high sensitivity, high resolution, a good pattern shape, and good line edge roughness in an ultrafine region, especially electron beam, X-ray or EUV light lithography, and to provide a pattern forming method using the same. SOLUTION: The active light sensitive or the radiation sensitive resin composition contains a resin (P) having: a repeating unit (A) that has an ionic structure part and produces an acid through decomposition by active ray or radiation irradiation; and a repeating unit (B) that has at least one phenolic hydroxyl group and a part of or all of the hydrogen atoms of the hydroxyl group or groups are each protected by the group which is eliminated by the action of an acid. The ionic structure part in the repeating unit (A) contained in the resin (P) has a structure in which an acid anion is produced at a side chain of the resin by active ray or radiation irradiation, and pKa of the produced acid is 0 or less. COPYRIGHT: (C)2010,JPO&INPIT