In-situ coherent lidar (ISICL): sensitivity sampling rate and practical considerations for using a particle mapper in plasma chambers and other inhospitable places

摘要

Abstract: The ISICL sensor is a recently described measurementdevice for sensing and mapping the temporal and spatialdistribution of isolated submicron particles insemiconductor processing plasma chambers, fluid tanks,and other inaccessible or hostile places. It requiresno modifications to the chamber, and senses the volumedirectly over the wafer, while the process is running.Its detection sensitivity is extremely high: even in avery bright plasma, it requires only 50 scatteredphotons to detect a particle at a false alarm rate of10$+$MIN@5$/ Hz. Here we present theoretical andexperimental results for the sensitivity and volumetricsampling rate of the sensor, as well as a method ofusing the measured pulse height histogram to obtainparticle size information, and some practical tests ofperformance versus window quality and back wallmaterial. !4