Four Field Stitching without Center Registration Marks
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-02
Four deflection fields in an electron beam wafer writer can be stitched without using a center registration mark on the semiconductor chip being processed. A relatively large number of registration marks, which are needed to achieve the required overlay, may be scanned using this method with only a slight increase in the number of table (stage) moves.