Patent ID: 7695986

Claim:
A method of controlling a processing tool in a semiconductor fabrication system, comprising: forming a first layer above a substrate, the first layer being formed of a first material; forming a second layer above the first layer, the second layer being formed of a second material and comprising at least one opening that exposes at least one portion of the first layer; accessing process state information associated with at least one material removal process performed in the processing tool, the process state information indicating at least one of a chemical state or a physical state of the processing tool when the processing tool is configured to perform said at least one material removal process in accordance with at least one process parameter; determining at least one selectivity of said at least one material removal process based on the process state information, said at least one selectivity indicating a difference between first and second rates of material removal for the first and second materials when said at least one material removal process is performed; modifying said at least one process parameter of said material removal process based on said at least one determined selectivity; and performing said material removal process according to said at least one modified process parameter to selectively remove portions of the first layer that are exposed by said at least one opening in the second layer.