Electron Beam Registration Mark Writing Method for Improved Field Stitching
Original Publication Date: 1985-Aug-01
Included in the Prior Art Database: 2005-Feb-19
By offsetting the electron beam fields used to write registration marks (write fields) one half a field dimension in both the horizontal and vertical directions relative to the reading and pattern writing fields (read fields), pattern stitching errors are reduced. When the pattern or chip size is larger than the field size of an electron beam writing system, very accurate registration (stitching) of adjoining fields must be obtained to assure continuity of lines crossing field boundaries. As shown in the figure, this is accomplished most accurately by writing four registration marks (A's) near the center of each registration mark writing field. Each registration mark is comprised of a set of vertical and horizontal bars.