Abstract: An automated method for aligning wafer surface scan maps and locating defects such as particle contaminant distributions on a wafer surface. More specifically, the invention is an automated method for locating added and removed contaminants and other defects on a semiconductor wafer surface after the wafer has undergone wafer-handling and/or processing. A second data set of a second scan of a wafer surface is misalignment-corrected to a first coordinate system of a first scan of the wafer surface. Thereafter, a final match is made between a first data set of the first scan and the misalignment-corrected data of the second scan. Non-matching locations in the misalignment-corrected data of the second scan represent added defects on the surface of the wafer. Non-matching locations in the base data of the first scan represent removed defects from the surface of the wafer.

Abstract: A method for reducing targeting errors encountered when trying to locate contaminant particles in a high-magnification imaging device, based on estimates of the particle positions obtained from a scanning device. The method of the invention includes scanning a semiconductor wafer in a scanning device, then preferably moving the wafer to a different orientation, and scanning the wafer again, to obtain at least two sets of particle coordinates that may differ slightly because of uncertainties in the scanning process. The multiple sets of coordinates are averaged to reduce the targeting errors, but only after transforming the coordinates to a common coordinate system. The transformation step includes computing transformation parameters for each possible pair of particles detected in at least two scans, averaging the results, and then transforming all of the particle coordinates to the common coordinate system.

Abstract: A method for reducing targeting errors encountered when trying to locate contaminant particles in a high-magnification imaging device, based on estimates of the particle positions obtained from a scanning device. The method of the invention uses three techniques separately and in combination. The first technique includes selecting at least three reference particles, to provide multiple unique pairs of reference particles for computation of an averaged set of coordinate transformation parameters, used to transform particle position coordinates from the coordinate system of the scanning device to the coordinate system of the imaging device. The averaged transformation parameters result in much smaller targeting errors between the estimated and actual positions of the particles. The targeting errors are further reduced by the use of multiple scans of the scanning device.