ABSTRACT
This chapter describes selected diagnostic methods used in plasma processing, with an emphasis on each method roughly proportional to its utility or frequency of use. Little coverage is given to diagnostic methods used in isolated research contexts. Information about the magnitude and time variation of the independent input parameters of the plasma-processing system is usually supplied by sensors built into the commercially available gas supply and plasma reactor subsystems. Diagnostic methods are required to measure the dependent output parameters of the plasma-processing system. Additional dependent output parameters include the directionality, selectivity, and uniformity of an etching process, and the uniformity, thickness, and adhesion of a deposition process. The gas-phase species monitored usually include the background neutral gas resulting from leakage and outgassing of the vacuum system; the (input) neutral working gas; the active species produced by interaction of the background and working gas with the plasma; and the chemical reaction products of plasma processing.
