Nanometer-scale wafer surface defect measurement based on state-space digital holographic microscopy

Non-destructive measurement of nanoscale surface defects plays a significant role in wafer production and processing. This paper proposes a method based on state-space digital holographic microscopy for measuring wafer surface defects with nanometer-scale accuracy. The angular spectrum method is used to numerically reconstruct the complex wavefront of the object, while reference holograms are applied for conjugate compensation, effectively reducing the effects of surface distortions and noise. To optimize phase estimation, the extended Kalman filter (EKF) method is employed, which can suppress noise, resolve phase unwrapping issues, and achieve accurate phase recovery from a single hologram, thereby extracting detailed defect information from wafer surfaces. Compared to traditional phase recovery methods, this approach demonstrates superior performance in high-noise environments, significantly improving defect measurement accuracy and achieving nanometer-level surface defect measurement. The proposed method has extensive application potential, especially in surface defect detection research for semiconductor manufacturing.