Application of SEM API on PWQ Wafer SEM Review

Abstract

Process Window Qualification (PWQ) is a good and well-established method to find systematic defects with high sensitivity and to qualify new masks and OPC revisions. The PWQ methodology is utilized to provide an extensive defectivity characterization to determine the absolute best conditions for focus and dose. This is achieved by taking into account the defectivity in the whole die and capturing all potential systematic defects. [1] This in turn had driven to more and more SEM review on this kind of PWQ wafer in wafer foundry. Manual SEM review of this PWQ wafer is time consuming and spending a lot of man power. In this paper, a new method of reviewing the PWQ wafer with API method and how it helps to resolve the current manual SEM review limitations is introduced.