Acoustic-optical metrology system and method for characterizing a sample and non-transitory computer readable medium

Abstract

Systems and methods of optical metrology and inspection are provided, including shaping a pump pulse to have a concave wavefront that generates, in a sample, an acoustic wave that converges at a focal location. When a subsurface feature is at the focal location, a reflected acoustic wave is generated, with a convex acoustic wavefront. A probe assembly is configured to shape a probe pulse to have a spherical wavefront and to impinge on the surface simultaneously with the return to the surface of a reflected acoustic wave. A detection assembly is configured to receive a reflected probe pulse, reflected from the surface, and, responsively, to determine whether the reflected probe pulse is indicative of surface changes induced by a reflected acoustic wave from a subsurface feature at the focal location.

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