High Speed Sample, Accumulate, Store, And Process Control Hardware
Original Publication Date: 1979-Oct-01
Included in the Prior Art Database: 2005-Feb-20
In the process of exposing wafers using electron (E)-beam lithography it becomes necessary to perform periodic deflection and beam calibrations in order to eliminate writing field distortions and maintain pattern writing quality. This is normally done by collecting backscatter signal information while scanning a calibrated target and then processing to generate corrections. Also, when overlaying previously processed layers, the deflection must be finely aligned with the target chips. This is done by feeding back signal data while scanning special alignment mark areas on each chip and again processing the data to generate corrections.