Abstract

An optical inspection method has been developed for finding defects in LSI lithographic patterns. A focused He–Ne laser beam scans the patterns on a wafer. The reflected diffraction waves around the wafer are observed. These diffraction waves indicate whether the patterns contain defects. To implement this judgment rapidly, signals of the waves characterizing the patterns are input directly into the address lines of random access memories. The system can detect a defect of ~0.8-μm diameter and inspect a 1-cm² chip in 9 s.

© 1988 Optical Society of America

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