E-beam inspection for detection of sub-design rule physical defects

E-beam inspection provides a complementary approach to brightfield inspection for detection of otherwise difficult to detect physical defects. Advantages of E-beam inspection include superior resolution, the ability to classify defects using patch images and automatic filtering of prior level defects. A key limitation, however, is throughput. Therefore brightfield inspection should always be used for defection of physical defects when effective. For challenging defects, E-beam inspection data may be used as a gold standard for development of the best optical inspection conditions. For very challenging defects, it may be necessary to rely on E-beam inspection. An efficient inspection should be developed. Three examples are presented of challenging defects to illustrate the usefulness of E-beam inspection for physical defect detection.