Inspection of PMMA photoresists infiltrated with varying amounts of InOx

Poly(methyl methacrylate) (PMMA) is used in the semiconductor industry as a model positive-tone extreme ultraviolet (EUV) photoresist. Many of these photoresists used commercially suffer from inherently low EUV sensitivity. This issue can be mitigated by incorporating high-Z elements into the organic polymer; however, a uniform distribution of these elements in the hybridized resist is of utmost importance. In this study, PMMA thin films spin-coated on silicon substrates were exposed to varying amounts of InOx (0, 1, 2, and 4 cycles) using vapor-phase infiltration. The molecular uniformity of the organic-inorganic photoresists was examined by nanoprojectile secondary ion mass spectrometry. The primary ion impacts (106–107), separated in time and space, produce mass spectra from each individual impact. The secondary ions were mass analyzed via time-of-flight.