Wavelength-dependent surface contour measurement system and method

Abstract

An optical metrology system for measuring a contour of a workpiece surface. The system includes a multi-wavelength light projector that projects a wavelength-varying collimated light beam onto the surface of the workpiece. The collimated light beam has a plurality of substantially parallel light rays, each of which has a predetermined wavelength. The wavelength of the plurality of light rays varies in a predetermined manner across a width of the collimated light beam. A wavelength-discriminating detector determines an intensity of light reflected from the workpiece surface and detects wavelength-specific characteristics of the received reflected light. Significantly, the wavelength-specific characteristics of the reflected light are related to the distance of the workpiece surface from the detector. Specifically, the multi-wavelength projector includes a collimated light source that generates a collimated light beam. A wavelength filter in the multi-wavelength projector is operatively positioned adjacent to the collimated light source to filter predetermined wavelengths of certain ones of said plurality of light rays to generate the wavelength-varying collimated light beam. The wavelength discriminating detector includes a photodetector matrix having a plurality of photosensitive elements forming an array of wavelength-sensitive light detector elements. A light receiver of the wavelength discriminating detector projects light reflected from one or more predetermined locations on the workpiece surface onto the photodetector matrix such that wavelength-specific characteristics and intensity information of the reflected light is recorded by the photodetector matrix.

Dependencies are inferred from the claim text.