摘要 |
A method for controlling an etch operation which is a rapid alternating process having etch and passivation phases is described. The method includes (a) supplying source power to an inductive coil of a plasma chamber, (b) initiating supply of a first process gas that flows along a distance separating a mass flow controller and the chamber, (c) detecting an optical signal from plasma generated within the chamber, with the optical signal being analyzed to identify a predefined change in amplitude relative to time, (d) triggering activation of bias power upon identifying the predefined change, the bias power being held active for a predefined amplitude duration during which the etch phase is primarily active, (e) initiating supply of a second process gas during a period in which the passivation phase is primarily active and the bias power is inactive, and (f) repeating (b)-(e) for additional cycles while processing an etch operation. |