Photo-Induced Fragmentation of a Tin-Oxo Cage Compound
Tin-oxo cage materials are of interest for use as photoresists for EUV (Extreme Ultraviolet) lithography (13.5 run, 92 eV), owing to their large absorption cross section for EUV light. In this work we exposed an n-butyl tin-oxo cage dication in the gas phase to photons in the energy range 4-14 eV to explore its fundamental photoreactivity. At all energies above the onset of electronic absorption at 5 eV (250 run) cleavage of tin-carbon bonds was observed. With photon energies >12 eV (<103 run) photoionization can occur, leading to 3+ ions. Besides the higher charge promotion, butyl chain loss without electron ejection (leading to 2+ fragments) still occurs.
Keywords: Tin-oxo cage, Photoresist, Mass spectrometry, Photochemistry