In order to obtain mask data for forming multiple metal-interconnection layers on a substrate, a plurality of rectangle patterns are generated which are respectively centered at cross points defined by straight lines that cross over each other at right angles. Further, a plurality of interconnection...http://www.google.de/patents/US5528512?utm_source=gb-gplus-sharePatent US5528512 - Method of obtaining mask data for manufacturing multiple metal-interconnection layers on a substrate
