Patent ID: 9666447
Date: 2017-05-30
CPC Classifications: H01L

Claim:
1. A method of etching a layer on a substrate, comprising: disposing a substrate having a heterogeneous layer composed of a first material and a second material in a processing space of a plasma processing system, wherein the heterogeneous layer has an initial upper surface exposing the first material and the second material to a plasma environment in the processing space, and performing a modulated plasma etching process to selectively remove the first material at a rate greater than removing the second material by applying radio frequency (RF) power pulses to a substrate holder that supports the substrate, the modulated plasma etching process including a modulation cycle that: (i) preferentially reacts an etchant with the first material during a first phase of the modulation cycle, and (ii) differentially adheres a passivant on the second material relative to the first material during a second phase of the modulation cycle, wherein pulsing the RF power further includes: wherein the second RF power level is less than the first RF power level, and the second time duration follows the first time duration.