Patent attributes
A positive resist composition that exhibits a large exposure margin, and excellent levels of resolution and dry etching resistance, as well as a method of forming a resist pattern that uses the positive resist composition. This resist composition includes a resin component (A), which contains acid dissociable, dissolution inhibiting groups and displays increased alkali solubility under the action of acid, and an acid generator component (B) that generates acid on exposure, wherein the resin component (A) contains a structural unit (a1) represented by a general formula (I) shown below, a structural unit (a2) in which a hydroxyl group within the above general formula (I) has been protected by substituting the hydrogen atom thereof with an acid dissociable, dissolution inhibiting group (II) represented by a general formula (II) shown below, and a structural unit (a3) in which a hydroxyl group within the above general formula (I) has been protected by substituting the hydrogen atom thereof with an acyclic acid dissociable, dissolution inhibiting group (III).
