E-beam defect review system

Abstract

An apparatus comprises an imaging unit to image a wafer to be reviewed, wherein imaging unit is the modified SORIL column. The modified SORIL column includes a focusing sub-system to do micro-focusing due to a wafer surface topology, wherein the focusing sub-system verifies the position of a grating image reflecting from the wafer surface to adjust the focus; and a surface charge control to regulate the charge accumulation due to electron irradiation during the review process, wherein the gaseous molecules are injected under a flood gun beam rather than under a primary beam. The modified SORIL column further includes a storage unit for storing wafer design database; and a host computer to manage defect locating, defect sampling, and defect classifying, wherein the host computer and storage unit are linked by high speed network.

Dependencies are inferred from the claim text.