PAG Study in EUV Lithography

Extreme Ultraviolet (EUV) has already achieved the initial requirements for 32 nm DRAM half pitch lithography rule and is known as one of the most promising next generation lithography techniques to be realized for 22 nm patterning technology though strict requirements for the power of the light sources, lithographic performance of the photoresist and the manufacturing and inspection of masks are still remaining,. In this report, we investigated the photolithographic characteristics of Photoacid Generator (PAG) additive approach in EUV lithography with different polymer platforms and sulfonium-type PAGs compared with other exposure techniques to understand the relationship between lithography results and photoresist materials. Four different sulfonium nonafluorobutanesulfonate; triphenylsulfonium nonafluorobutanesulfonate (TPS), tri(4-methoxy-3,5-dimethylphenyl) sulfonium nonafluorobutanesulfonate (MDP), tri(4-methoxy-3-methylphenyl)sulfonium nonafluorobutanesulfonate (MNIP) and tri(4-methoxy-3-phenylphenyl)sulfonium nona-fluorobutanesulfonate (MPP) were employed as PAG in order to study the fundamental properties, such as sensitivity, photo-efficiency, lithographic performance, in the two different model formulations, poly(hydroxystyrene) (PHS) type and poly(methacrylates)-type, under three different exposures of 193 nm (ArF), Electron Beam (EB) and EUV.