High-sensitivity molecular organometallic resist for EUV (MORE)

Abstract

We have developed organometallic carboxylate compounds [R_nM(O₂CR’)₂] 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_nM(O₂CR’)₂ where we have studied seven R groups, four main group metals (M), and three polymerizable carboxylate groups (O₂CR’). We found that the greatest predictor of sensitivity of the R_nSb(O₂CR’)₂resists 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_max <i>vs.</i> POL for a variety of molecules of the type R₃Sb(O₂CR’)₂ lend insight into the behaviour of these resists.