Patent ID: 7871002
Filing Date: 2011-01-18
Classification: G03F

Abstract:
1. A method of determining intra-field distortion for a projection imaging tool, the method comprising: exposing a self-referenced rectangular grid reticle pattern onto a substrate with a recording media, wherein the self-referenced rectangular grid reticle pattern includes at least two arrays of alignment attributes such that the arrays of alignment attributes have features complementary to each other and the arrays are offset from each other in distinct directions; repeating exposing the self-referenced rectangular grid reticle pattern onto the substrate thereby producing a desired number of subsequent exposures, wherein subsequent self-referenced rectangular grid reticle patterns overlap previous self-referenced rectangular grid reticle patterns and are shifted in desired directions, thereby creating interlocked completed alignment attributes and grid alignment attributes; exposing a reference reticle pattern onto the substrate, wherein the reference reticle pattern overlaps the grid alignment attributes, thereby creating completed grid alignment attributes; measuring positional offsets of the completed alignment attributes and completed grid alignment attributes; and determining an intra-field distortion from the measured offsets.