Methods and apparatus for scanned beam uniformity adjustment in ion implanters

摘要

Methods and apparatus are provided for adjusting the profile of a scanned ion beam. The spatial distribution of the unscanned ion beam is measured. The ion beam is scanned at an initial scan speed, and the beam profile of the scanned ion beam is measured. If the measured beam profile is not within specification, a scan speed correction that produces a desired profile correction is determined using a calculation which is based on the spatial distribution of the unscanned ion beam. The scan speed correction may be determined by convolving a candidate scan speed correction with the spatial distribution of the unscanned ion beam to produce a result and determining if the result is sufficiently close to the desired profile correction. A multi-dimensional search algorithm may be used to select the candidate scan speed correction. The ion beam is scanned at a corrected scan speed, which is based on the initial scan speed and the scan speed correction, to produce corrected beam profile.