US Patent 7875859 Ion energy analyzer and methods of manufacturing and operating

An ion energy analyzer is described for use in diagnosing the ion energy distribution (IED) of ions incident on a radio frequency (RF) biased substrate immersed in plasma. The ion energy analyzer comprises an entrance grid exposed to the plasma, an ion selection grid disposed proximate to the entrance grid, an electron rejection grid disposed proximate to the ion selection grid, and an ion current collector disposed proximate to the electron rejection grid. The ion selection grid is coupled to an ion selection voltage source configured to positively bias the ion selection grid by an ion selection voltage, and the electron rejection grid is coupled to an electron rejection voltage source configured to negatively bias the electron rejection grid by an electron rejection voltage. Furthermore, an ion current meter is coupled to the ion current collector to measure the ion current.