ONIUM SALT, RESIST COMPOSITION, AND PATTERNING PROCESS

摘要

An onium salt having an anion moiety of a specific structure is an effective photoacid generator. A resist composition comprising the onium salt has the advantages of compatibility and reduced acid diffusion and forms a pattern with a good balance of sensitivity and MEF, rectangularity, and minimal defects.

主权项

1. An onium salt having the formula (1): wherein R1 is a straight, branched or cyclic C1-C40 monovalent hydrocarbon group which may contain a heteroatom, L1 is a carbonyl bond, sulfonyl bond or sulfinyl bond, L2 is a single bond, ether bond, carbonyl bond, ester bond, amide bond, sulfide bond, sulfinyl bond, sulfonyl bond, sulfonic acid ester bond, sulfinamide bond, sulfonamide bond, carbamate bond or carbonate bond, A1 is hydrogen, halogen or a straight, branched or cyclic C1-C20 monovalent hydrocarbon group which may contain a heteroatom, Xa and Xb are each independently hydrogen, fluorine or trifluoromethyl, with the proviso that at least one of Xa and Xb is a substituent group other than hydrogen, k1 is an integer of 1 to 4, and M+ is an onium cation.