Patent ID: 6538249
Filing Date: 2003-03-25
Classification: G06T,H01J

Abstract:
An image-formation apparatus using charged particle beams comprising:a charged particle source for emitting charged particle beams under various focus conditions; a scan deflector for scanning a charged particle beam emitted from the charged particle source on a sample; a charged particle detector for detecting charged particles emitted from a plurality of points on a surface portion of said sample in response to the charged particle beams under various focus conditions, and for generating a pixel signal corresponding to each of the various focus conditions for each of the plurality of points in response to the detected charged particles; and a data processing system configured to perform the machine-implemented steps of: determining an in-focus status of the pixel signal corresponding to each of the various focus conditions for each of the plurality of points; for each of the plurality of points on said surface portion of said sample, selecting a preferred pixel signal from pixel signals corresponding to the various focus conditions for each of the plurality of points based on in-focus statuses thereof; and generating a two-dimensional image of said surface portion of said sample based on the preferred pixel signals corresponding to the plurality of points on said surface portion of said sample.