Study of the Critical Dimension Shrinkage Caused by After Development Inspection

In this study, a 3x-nm after development inspection (ADI) wafer with focus exposure matrix (FEM) was inspected with both an advanced optical system and an advanced electron beam inspection (EBI) system. We found that EBI system could capture many more defects than the optical system and that it could provide more information about the reticle shot defect distribution. It has a high capture rate for certain critical defects, such as nano-bridges, that are insensitive to an optical system. We also studied the critical dimension (CD) variations caused, by the optical inspection and by the EBI.