Patent ID: 9726984
Date: 2017-08-08
CPC Classifications: G03F

Claim:
1. A method, comprising: translating an aperture located at an aperture plane of a scatterometry metrology tool to a plurality of aperture positions within the aperture plane; performing, with the scatterometry metrology tool, an overlay measurement of a periodic structure at each aperture position of the plurality of aperture positions; calculating, with one or more processors, an overlay variation measure for each aperture position of the plurality of aperture positions, wherein the overlay variation measure is configured to correlate to a deviation of the aperture from an aligned aperture position; determining, with one or more processors, the aligned aperture position based on the calculated overlay variation measures for each aperture position of the plurality of aperture positions; and aligning the aperture in the scatterometry metrology tool to the aligned aperture position within the aperture plane.