Radiation-sensitive composition, pattern formation method, and polymer

Abstract

The present invention addresses the problem of providing: a radiation-sensitive composition and a pattern formation method with which it is possible to achieve sufficient levels of sensitivity, development contrast, development residue suppression property, and limit resolution property during formation of a pattern; and a polymer which can be used suitably for the radiation-sensitive composition. The radiation-sensitive composition contains: a polymer (A) containing a structural unit that has an acid-dissociable group, a structural unit that has a first organic acid anion (b1) and a first onium cation (c1) and includes a first acid-generating structure capable of generating, when exposed, an acid that induces the dissociation of the acid-dissociable group, and a structural unit that has a second organic acid anion (b2) and a second onium cation (c2) and includes a second acid-generating structure capable of generating, when exposed, an acid that does not induce the dissociation of the acid-dissociable group; and a solvent (B). The polymer (A) includes a partial structure represented by formula (i). (In formula (i), Ar represents a 5- to 20-membered aromatic ring having a valency of (m1 + m2 + m3 +1); X1 represents a hydroxy group, a carboxy group, a sulfonic acid group, or a mercapto group, wherein, when there are a plurality of X1's, the plurality of X1's are the same as or different from each other; R1 represents an acid-dissociable group or a non-acid-dissociable group, wherein, when there is one R1, the R1 represents an acid-dissociable group, and when there are a plurality of R1's, at least one of the plurality of R1's represents an acid-dissociable group, and when there are a plurality of R1's, the plurality of R1's are the same as or different from each other; R2 represents a halogen atom, a cyano group, a nitro group, or a monovalent organic group (excluding -COOR1), wherein, when there are a plurality of R2's, the plurality of R2's are the same as or different from each other; m1 represents an integer of 1-5, m2 represents an integer of 0-5, and m3 represents an integer of 0-6, wherein 2 ≤ m1 + m2; and "*" represents a bond to another structure in the polymer (A).)