Two perfluoroaryl sulfonates were tested as initiators for the extreme ultraviolet (EUV)-promoted polymerization of silicabased hybrid organic-inorganic films containing epoxy moieties. One of the sulfonates was able to strongly improve the polymerization efficiency in the tested materials and behaved much better than the commercial photoacid generator diphenylsulfonium (4-phenylthiophenyl)diphenylsulfonium triflate. Furthermore, lithographic patterns with sub-micrometric reso-lutions were achieved by irradiating resists containing the selected sulfonate (1 % molar concentration) at very low EUV doses (about 10 mJ cm À2 ). The proposed combination of specifically designed perfluoroaryl sulfonates and hybrid organic-inorganic materials is a starting point to develop highperformance and cost-effective EUV-sensitive resists for the microelectronic industry.[a] Dr. CAT = À1.60 V and À1.50 V vs. Ag/AgCl, 3 M NaCl, respectively), thus potentially suitable for EUVL.