Digital Image Correction Methods Using Dark-Field Digital Holographic Microscopy for Semiconductor Metrology

In semiconductor fabrication industry, the demand for faster and more reliable optical metrology systems increases with the continued shrinking of feature sizes in integrated circuits. We present digital holographic microscopy for diffraction-based overlay metrology that opens new possibilities to image small metrology targets with weak diffraction efficiencies using simple optics, and digitally correct experimental imperfections.