Scanner focus and CD response characterization metrology for sub 180 nm lithography

Abstract

The rapid pace in scanner technology has produced a situation where many process layers will have to be manufactured with a minimum depth of focus (DOF) of approximately 0.3 um with very stringent critical dimension (CD) control. This paper explores the application of Optical Critical Dimension (formerly called OCD, now MX-SMP) technology to measure and evaluate focus in addition to the CD response across the wafer.