Abstract: A system and method for inspecting structures formed on the surface of an object using ultraviolet (UV) light. The object is placed in position and illuminated with at least one wavelength of UV light, directed at its surface from a UV source. At the moment of illumination, an image is captured by a UV-light sensitive camera positioned at an angle calculated to intercept light diffracted at particular an angle of diffraction associated with the pattern of structures formed on the surface of the object. To avoid having to repeatedly reposition the camera, one (or more in succession) illumination wavelength is selected to direct an intensity peak associated with a particular order of diffraction at the camera location. Ideally, a visible-light sensitive camera is also used to capture images of the surface when illumination with UV light results in the emanation of light in the visible portion of the spectrum.

Abstract: A system and method for detecting defects in surface structures, such as those formed on semiconductor wafers. A light source, preferably a strobe light, provides illumination that is separated by a filter into a plurality of selected bandwidths. The light then is transported through a fiber optic cable to a diffuser, and from there directed toward the surface. A camera captures a plurality of images, each image formed by a separate portion of the electromagnetic spectrum. The images may be formed by either reflected or diffracted light, or both. The images may be stored or compared to an image of a calibration wafer.