US Patent 8225683 Wafer bow metrology arrangements and methods thereof

An arrangement for quantifying a wafer bow. The arrangement is positioned within a plasma processing system is provided. The arrangement includes a support mechanism for holding a wafer. The arrangement also includes a first set of sensors, which is configured to collect a first set of measurement data for a plurality of data points on the wafer. The first set of measurement data indicates a minimum gap between the first set of sensors and the wafer. The first set of sensors is positioned in a first location, which is outside of a set of process modules of the plasma processing system.