Patent ID: 8273837

Claim:
A polymer comprising a first repeating unit derived from a compound shown by the following formula (1), wherein R 1 represents a methyl group or a hydrogen atom, R 2 individually represents a substituted or unsubstituted monovalent organic group having 1 to 10 carbon atoms, n is an integer from 0 to 3, R 3 and R 4 individually represent a substituted or unsubstituted monovalent aryl group, A represents a methylene group, a linear or branched alkylene group having 2 to 10 carbon atoms, or an arylene group, and X − represents a sulfonate ion, a BF 4− ion, a PF 6− ion, or a tetraarylboronium ion, and a second repeating unit having an acid-dissociable group, and wherein the polymer has a polystyrene-reduced weight average molecular weight measured by gel permeation chromatography (GPC) of 1,000 to 100,000.