Patent ID: 9704690
Date: 2017-07-11
CPC Classifications: H01J

Claim:
1. A plasma apparatus comprising: a process chamber having an inner, enclosed space; a chuck disposed in the process chamber and having a top surface configured to load a substrate; a gas supply unit supplying a process gas into the process chamber; a plasma generating unit configured to generate plasma over the chuck; a direct current (DC) power generator configured to apply a DC pulse signal to the chuck; and a sensor configured to monitor a state of the plasma and provide a sensing signal to the DC power generator, wherein the DC pulse signal comprises a series of periods, wherein each period of the DC pulse signal comprises: a negative pulse duration during which a negative pulse is applied; a positive pulse duration during which a positive pulse is applied; and a pulse-off duration during which the negative pulse and the positive pulse are turned-off, and wherein the DC power generator is configured to change at least one of a magnitude of the positive pulse and a length of the positive pulse duration of an n+1