Defect 3-D Profile Estimation Using SEM Images

Abstract

In semiconductor wafer manufacturing process, the height of random defects provides an important physical parameter to understand their impact and root cause. In this work, we demonstrate a novel method of defect height estimation based on SEM images without using ground truth or any external reference data of target defect types. Our method is applicable in conditions such as absence of shadows, self-obstruction by defects, lack of precise knowledge of SEM detector geometry and does not require sample tilting or imaging at different working distances, thereby removing major limitations of previous work. The error in our height estimation is 3% compared with 11% for current manual method on same dataset. In addition to improving accuracy and precision, our method reduces the time and manual effort required and can be easily extended to past and new defects for trend monitoring purpose, thus satisfying some key requirements of manufacturing environment.