US Patent 11476091 Impedance matching network for diagnosing plasma chamber

In one embodiment, a method of using an impedance matching network to determine a plasma chamber characteristic is disclosed. An impedance matching network is coupled between a radio frequency (RF) source and a plasma chamber. The matching network includes a variable reactance element (VRE) having different positions for providing different reactances. A characteristic of the plasma chamber is determined based on reference values for a parameter of the matching network and a current value. Based thereon, either a visual or audible indication of the determined characteristic of the plasma chamber is provided, or an action is taken to address the determined characteristic.