Depth-synchronized adaptive coherence scanning interferometry for rapid 3D morphology of composite high-aspect-ratio...

In this Letter, we introduce depth-synchronized adaptive coherence scanning interferometry (DA-CSI) for rapid three-dimensional (3D) morphology of composite high-aspect-ratio micro-trenches. A deformable mirror is employed to dynamically compensate for sample-induced aberrations during a single axial scan, eliminating the need for preliminary scans or repeated corrections and thereby improving the measurement efficiency. We further develop both a 3D point-spread function model for depth-synchronized compensation and a model-based axial signal-matching approach to effectively reconstruct the interferometric signals. Experiments on ten-depth trenches achieve depth errors below 0.7%, repeatability better than 0.8%, an 85% reduction in acquisition time, and an 81% reduction in total acquisition-plus-processing time, demonstrating the accuracy and efficiency of DA-CSI.