Patent ID: 6734971
Filing Date: 2004-05-11
Classification: G03F

Abstract:
A method of determining inter-field overlay error of a stage on a projection imaging tool, the method comprising:exposing a first reticle pattern onto a substrate with a recording media, thereby producing a first exposure, wherein the first 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; exposing a second reticle pattern onto the substrate thereby producing a second exposure, wherein the second reticle pattern overlaps the first reticle pattern and is shifted in a desired direction so that at least one row or column of alignment attributes of the first exposure overlays with at least one row or column of complementary attributes of the second exposure, thereby creating an interlocking row or column of completed attributes; measuring positional offsets of the alignment attributes in the interlocking row or column of completed attributes; and determining a stage distortion and yaw error map from the offsets.