Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2015 · 51 citations · 5 references
We have developed organometallic carboxylate compounds [R<sub>n</sub>M(O<sub>2</sub>CR’)<sub>2</sub>] capable of acting as negativetone EUV resists. Overall, the best and fastest resists contain antimony, are pentavalent and the carboxylate group contains a polymerizable olefin (e.g. acrylate, methacrylate or styrenecarboxylate). Evidence suggests that high sensitivity is achieved through the polymerization of olefins in the exposed region. We have performed a systematic sensitivity study of molecules of the type R<sub>n</sub>M(O<sub>2</sub>CR’)<sub>2</sub> where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O<sub>2</sub>CR’). We found that the greatest predictor of sensitivity of the R<sub>n</sub>Sb(O<sub>2</sub>CR’)<sub>2 </sub>resists is their level of polymerizable olefins. We mathematically define the polymerizable olefin loading (POL) as the ratio of the number of olefins vs. the number of non-hydrogen atoms. Linear and log plots of E<sub>max</sub> <i>vs.</i> POL for a variety of molecules of the type R<sub>3</sub>Sb(O<sub>2</sub>CR’)<sub>2</sub> lend insight into the behaviour of these resists.
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