RADIATION SENSITIVE RESIN COMPOSITION, PATTERN FORMING METHOD AND ONIUM SALT COMPOUND

The present invention provides: a radiation sensitive resin composition which is capable of exhibiting sensitivity, CDU performance and LWR performance at sufficient levels; and a method for forming a resist pattern. A radiation sensitive resin composition which contains an onium salt compound, a resin that contains a structural unit having an acid cleavable group, and a solvent, wherein the onium salt compound is at least one compound that is selected from the group consisting of an onium salt compound (1) represented by formula (1) and an onium salt compound (2) represented by formula (2). (In formula (1), R1 represents a hydrogen atom or a monovalent organic group having from 1 to 40 carbon atoms; each of R2 and R3 independently represents a hydrogen atom, a halogen atom, a carboxy group, an amino group or a monovalent organic group having from 1 to 40 carbon atoms, or alternatively, R2 and R3 combine with each other to form a ring structure having from 5 to 8 ring members together with two carbon atoms to which these moieties are bonded; each of X1 and X2 independently represents an oxygen atom or a sulfur atom, provided that the X1 and X2 moieties are not sulfur atoms at the same time; and Z1 + represents a monovalent radiation sensitive onium cation. In formula (2), R1 represents a hydrogen atom, a halogen atom, or a monovalent organic group having from 1 to 40 carbon atoms; each of R5 and R6 independently represents a hydrogen atom or a monovalent organic group having from 1 to 40 carbon atoms, or alternatively, R5 and R6 combine with each other to form a ring structure having from 3 to 8 ring members together with a nitrogen atom to which these moieties are bonded; and Z2 + represents a monovalent radiation sensitive onium cation.) La présente invention concerne : une composition de résine sensible aux rayonnements qui est susceptible de présenter une sensibilité, des performances de CDU et LWR à des niveaux suffisants; et un procédé de formation d'un motif de résine photosensible. Une composition de résine sensible aux rayonnements qui contient un composé de sel d'onium, une résine qui contient une unité structurale ayant un groupe clivable par un acide, et un solvant, le composé de sel d'onium étant au moins un composé qui est choisi dans le groupe constitué par un composé de sel d'onium (1) représenté par la formule (1) et un composé de sel d'onium (2) représenté par la formule (2). (Dans la formule (1), R1 représente un atome d'hydrogène ou un