Recent Advances In Automated Patterned Wafer Inspection

An automated patterned wafer inspection system has been developed with submicron sensitivity which is capable of inspecting a complete 150mm wafer in less than three and a half minutes. The system was designed to be used on-line in a production environment to assist the process engineer in identifying critical yield limiting process steps. The system can be interfaced to an automated off-line defect review microscope which allows for the classification of defects. An overview of the optical system and unique signal processing techniques will be presented. Performance results on a variety of different process levels on various types of patterned wafers will be discussed.