Abstract: An inspection system for inspecting multiple surfaces of a substrate includes at least one illuminator that produces light at a first wavelength that is incident on the substrate at a first angle (e.g., normal) and light at a second wavelength directed that is obliquely incident on the substrate. An adjustment system adjusts the oblique angle. The substrate may be opaque to one of the wavelengths and at least partially transparent to the other wavelength. Detection optics collect backscattered light from the substrate and at least one detector generates a first image representative of the first surface of the substrate and a second image representative of a second surface or near the second surface of the substrate. The images may be compared to generate a third image representative of defects on or near the second surface of the substrate corrected for residual signals of defects on the first surface.