Patent ID: 6906780

Claim:
A method of determining a scanning lens distortion in a projection imaging tool having a reticle, the method comprising: exposing a reticle pattern onto a substrate having a recording media in a first position, wherein the reticle pattern includes at least two arrays of alignment attributes, the arrays of alignment attributes having features complementary to each other and the arrays have the same pitch and are offset from each other; exposing the reticle pattern onto the substrate in a second position, wherein the reticle pattern in the second position overlaps the reticle pattern in the first position and is shifted in a direction perpendicular to a scanning direction by an amount that corresponds to the array offset; rotating the substrate a desired angular amount and exposing the reticle pattern onto the substrate in a third position, wherein the reticle pattern in the third position overlaps the reticle pattern in the first position; measuring positional offsets of the alignment attributes of the overlapped exposed patterns on the substrate; and determining a scanning lens distortion map from the positional offset measurements.