Polymer, chemically amplified positive resist composition and pattern forming process

A polymer comprising recurring units of a fluorinated carboxylic acid onium salt having the general formula (1):

• wherein R1 is a structure derived from a basis skeleton capable of providing the polymerization activity of a polymerizable monomer, represented by any one of the formulae:
• wherein the valence bond extending from the oxygen atom in the structure designates a bond to W1,
• R2 is fluorine or a fluoroalkyl group,
• W1 is a divalent organic group, and
• Q+ is a sulfonium cation of the general formula (a) or (b) or a iodonium cation of the general formula (c):
• wherein R3, R4 and R5 are each independently a substituted or unsubstituted, straight or branched C1-C10 alkyl, alkenyl or oxoalkyl group or a substituted or unsubstituted C6-C18 aryl, aralkyl or aryloxoalkyl group, or at least two of R3, R4 and R5 may bond together to form a ring with the sulfur atom,
• wherein R6 is a substituted or unsubstituted, straight, branched or cyclic C1-C20 alkyl or alkenyl group or a substituted or unsubstituted C6-C14 aryl group, m is an integer of 1 to 5, n is 0 or 1, R6 may have a carbonyl group, hydroxyl group, ester structure, lactone structure, amino group, amide group or ether-bonding oxygen atom substituted thereon,
• wherein R6 is a substituted or unsubstituted, straight, branched or cyclic C1-C20 alkyl or alkenyl group or a substituted or unsubstituted C6-C14 aryl group, m is an integer of 1 to 5, n is 0 or 1, R6 may have a carbonyl group, hydroxyl group, ester structure, lactone structure, amino group, amide group or ether-bonding oxygen atom substituted thereon.