Spectral-domain optical coherence tomography with a white light developed for optical device fabrication

We developed a spectral-domain optical coherence tomography (SD-OCT) with a white light source for high-resolution, non-destructive profile imaging. By using a 625-nm-centered white light (260 nm bandwidth), 0.69 /nm of axial resolution was achieved. This resolution is suitable for the inspection of thin photoresists (e.g., 1-2 μm) coated semiconductor wafers, which are used for optical device fabrication.