Patent ID: 9490107
Filing Date: 2016-11-08
CPC Classification: H01J

Claim Text:
1. A plasma apparatus comprising: a process chamber having an inner space; a chuck disposed in the process chamber, the chuck 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 generating plasma over the chuck; and a direct current (DC) power generator configured to apply a DC pulse signal having repetitive periods to the chuck, each period of the DC pulse signal comprising a negative pulse duration during which a negative pulse is applied; a positive pulse duration during which a positive pulse is applied; a stable duration after the negative pulse duration and before the positive pulse duration; and a pulse-off duration, after the positive pulse duration and prior to subsequent application of a negative pulse, during which the negative pulse and the positive pulse are turned off, wherein the direct current (DC) power generator is configured to apply the DC pulse signal in a manner such that the pulse-off duration is longer than the stable duration to allow etch by-products, formed during plasma generation, to escape from an etch region of the substrate.