Patent ID: 6635395
Filing Date: 2003-10-21
Classification: B82Y,G03F,H01J,Y10S

Abstract:
A method for exposing a layout comprising multiple layers on a wafer, comprising:photolithographically exposing at least one layer that contains selected structural features; aligning the wafer coarsely with respect to an electron beam exposure system in such a way that a surface area of the previously photolithographically exposed layer is located in a deflection region of the electron beam; scanning the surface area in the X and Y direction in spot fashion with the electron beam and thereby exposing at least one further layer with the electron beam of the electron beam exposure system; detecting radiation backscattered from individual spots; obtaining, from the intensities of the radiation backscattered from the individual spots, an actual data set that corresponds to a raster image of that surface area with the wafer in the actual position; comparing the actual data set to a stored reference data set that corresponds to the raster image (template) of the same surface area with the wafer in the reference position; deriving information from the deviation between the two data sets, as to the deviation between the actual position and the reference position; causing, on the basis of that information, a positional change of the wafer in order to bring the actual position closer to the reference position; and obtaining an actual data set and comparing it to the reference data set until no further deviation is ascertained.