A system and method are used to limit a proportion of a programmable patterning means used to pattern a substrate. This is done such that a size of a repeated pattern to be exposed on the substrate is an integer multiple of a size of a pattern exposed on the substrate by the patterned beam....http://www.google.com.au/patents/US7385677?utm_source=gb-gplus-sharePatent US7385677 - Lithographic apparatus and device manufacturing method that limits a portion of a patterning device used to pattern a beam
