Patent ID: 8440372
Filing Date: 2013-05-14
Classification: G03F

Abstract:
1. A set of photomasks for stitching an image of a first field to an image of a second field on a substrate, comprising: a zero mask comprising a first set of targets formed on a first side of the zero mask and a second set of targets formed on a second side, opposite the first side, of the zero mask, the zero mask to be applied to the substrate having no previous alignment marks formed thereon for the zero mask to align to, the zero mask forming a first set of alignment marks in the substrate from the first set of targets and forming a second set of alignment marks in the substrate from the second set of targets; a first field mask comprising the image of the first field and configured to align to the first set of alignment marks on the substrate formed by the first set of targets of the zero mask; and a second field mask comprising the image of the second field and configured to align to the second set of alignment marks on the substrate formed by the second set of targets of the zero mask, wherein the image of the first field is stitched to the image of the second field on the substrate when the first field mask is aligned to the first set of alignment marks and the second field mask is aligned to the second set of alignment marks.