Illinois Plasma Institute graduate student Christian Williams successfully defended his preliminary exam titled “Plasma-Activated Liquids with Applications to the Semiconductor Industry using the Integrated circuit Manufacturing with Plasma Activated Chemical Treatment (IMPACT) Tool.”

This work investigates the potential of atmospheric plasma treatment of a liquid (TMAH) used in semiconductor manufacturing for etching and lithography processes. The efficacy of this technique is initially measured by comparing film removal ability on a TiO2-coated wafer using x-ray fluorescence spectroscopy, with and without plasma treatment. After confirming the increased cleaning efficiency, the root cause was examined by observing changes in pH, oxidative-reductive potential (ORP), and the presence of hydroxyl radicals and H2O2 using UV-vis spectroscopy and HPLC. Byproduct analysis was conducted using electro-spray ionization mass spectrometry (ESI-MS), and gas phase analysis through atmospheric RGA and Fourier-Transform Infrared (FTIR) spectroscopy. Preliminary results suggest that either hydroxylamine (NH2OH) or various dimethylated amines formed through OH radical interactions are responsible for the observed effects.