| 摘要 |
The present invention provides the onium salt comprises the material represented by the following general formula (0-1), wherein Rf represents a fluorine atom or a trifluoromethyl group; Y represents a cyclic hydrocarbon group having 3 to 30 carbon atoms, the hydrogen atom in the cyclic hydrocarbon group may be substituted by a hetero atom itself or a monovalent hydrocarbon group which may be substituted by a hetero atom(s), and the hetero atom(s) may be interposed into the cyclic structure of the cyclic hydrocarbon group and the monovalent hydrocarbon group; and M+ represents a monovalent cation. There can be provided an onium salt which can improve resolution at the time of forming a pattern and give a pattern with less line edge roughness (LER) when it is used in a chemically amplified positive resist composition. |
