Toroidal Remote Plasma Sources for Charge-Sensitive Applications

This White Paper presents an experimental verification of the MKS toroidal remote plasma sources (RPS) for semiconductor applications, specifically focusing on their impact on silicon wafer charging. The study outlines the concern of plasma process induced charging damage (PID) as semiconductor devices become smaller and more sensitive. It details the methodology used to assess the delivery of neutral radical reactants compared to charged species using an industry-standard wafer charging monitor. The results indicate that the MKS Paragon and R*evolution RPS units do not contribute to damaging on-wafer charges under various gas species and process conditions. The paper discusses the effects of showerheads and ignition methods on potential charging, highlighting that the presence of a showerhead can block some charges from reaching the wafer surface. Additionally, it compares the performance of the RPS units against a remote inductively coupled plasma source, demonstrating significantly lower charge transport with the RPS units, thus confirming their suitability for charge-sensitive applications.