Monitoring substrate processing by detecting reflectively diffracted light

摘要

A substrate is placed in a process zone and an energized process gas is maintained in the process zone to process the substrate. A light beam is reflectively diffracted from a pattern of features of the substrate being processed, the reflected beam is monitored, and a signal is generated in relation to the monitored beam. During processing, a width of the features of the substrate can change. The generated signal is evaluated to detect the occurrence of a change in the width of the features.