Jeremy Jacob Harry Mettler, a Ph.D. candidate at NPRE/IPI, has successfully passed the preliminary exam on his research on etching-based fluorine radical probes. Mettler’s work focuses on developing and applying novel radical probe designs to achieve spatially resolved measurements of fluorine density in plasma systems, a critical factor in reactive ion etching (RIE) processes. His research involves catalytic probe material testing and the use of tungsten etching probes, demonstrating a linear relationship between probe response and fluorine radical density measured via actinometry. By addressing the limitations of traditional actinometry techniques and incorporating non-equilibrium probe analysis, Mettler’s work aims to enhance the understanding of etching kinetics and improve the precision of fluorine radical measurements, thus contributing significantly to the advancement of semiconductor etching techniques.