High-sensitivity wide-field defect detection using single-shot hybrid finite-difference phase microscopy

As the critical dimensions of integrated circuits continue to shrink deep into the sub-wavelength regime, the resulting low signal-to-noise ratio renders conventional optical microscopy inadequate for the reliable detection and classification of defects. Here, we report a low-noise, single-shot hybrid finite-difference phase imaging method that detects nanoscale defects over a large field of view using visible light. The system utilizes a common-path interferometer integrated with dynamic speckle illumination and a custom 2D phase grating to suppress noise and amplify faint defect signatures effectively. High sensitivity is achieved, enabling the successful detection, localization, and classification of defects with linewidths as small as 30 nm. This approach yields a significant defect contrast from a baseline of 17.55 dB to 65.11 dB, offering a robust solution for high-throughput semiconductor metrology.