METHOD FOR ATOMIC LAYER ETCHING

摘要

A method of etching a layer on a substrate includes disposing a substrate in a plasma processing system configured to facilitate an etching process (112), performing an atomic layer etching process cycle to etch a monolayer of an exposed surface of the substrate (114-117), and repeating the atomic layer etching process cycle until a target depth is reached (120). Each process cycle etches the monolayer from the exposed surface. The atomic layer etching process cycle sequentially includes forming an adsorption monolayer comprising an etchant on an exposed surface of the substrate by introducing the etchant (114) while concurrently coupling electromagnetic power to the plasma processing system at a power level targeted to achieve an etchant radical flux at the substrate greater than a total ion flux at the substrate, which power level is less than or equal to 50 W (118), purging the plasma processing system to remove any excess etchant (115), desorbing the adsorption monolayer by exposing the adsorption monolayer to gas ions to activate a reaction of the etchant (116), and purging the plasma processing system again (117).