Comparative simulation study of computational imaging microscopy for nanoscale defect measurement

Detecting patterning defects in sub-10 nm nanoscale patterns is critical for device reliability and yield but remains challenging due to the limitations of traditional optical inspection systems. This simulation study explores Fourier Ptychographic Microscopy (FPM) and Structured Illumination Microscopy (SIM) for nanoscale defect metrology using short wavelengths, with simulations conducted using a commercial finite-different time domain (FDTD) platform. FPM combines high-resolution and large field-of-view imaging with phase retrieval algorithms to enhance defect detectability, while SIM improves resolution by introducing spatial carrier frequencies and expanding spatial frequency content through moiré fringes. Simulated images of defects within nanoscale gate patterns are analyzed to compare resolution, signal-to-noise ratio, and detectability. This work considers the potential of integrating these techniques to address challenges in nanoscale defect metrology.