Patent ID: 8962488
Filing Date: 2015-02-24
Classification: C23F,H01J,H01L

Abstract:
1. A method of etching a dielectric layer on a substrate, comprising: generating a plasma by pulsing a first RF source signal having a first duty cycle; applying a second RF bias signal having a second duty cycle to the plasma; applying a third RF bias signal having a third duty cycle to the plasma, wherein the first, second, and third signals are synchronized; adjusting a phase variance between the first RF source signal and at least one of the second or third RF bias signals to control at least one of plasma ion density non-uniformity in the plasma or charge build-up on the dielectric layer, wherein an RF frequency of the first RF signal is a very high frequency (VHF) frequency, and wherein an RF frequency of each of the second RF bias signal and the third RF bias signal is a low frequency (LF), medium frequency (MF), or high frequency (HF) frequency; and etching the dielectric layer with the plasma.