Dissociative photoionization of EUV lithography photoresist models

The dissociative photoionization of \\textit{tert}-butyl methyl methacrylate,\na monomer unit found in many ESCAP resists, was investigated in a gas phase\nphotoelectron photoion coincidence experiment employing extreme ultraviolet\n(EUV) synchrotron radiation at 13.5 nm. It was found that the interaction of\nEUV photons with the molecules leads almost exclusively to dissociation.\nHowever, the ionization can also directly deprotect the ester function, thus\ninducing the solubility switch wanted in a resist film. These results serve as\na building block to reconstruct the full picture of the mechanism in widely\nused chemically amplified resist thin films, provide a knob to tailor more\nperformant resist materials, and will aid interpreting advanced ultrafast\ntime-resolved experiments.\n