KLA Corporation
Field-to-Field Corrections Using Overlay Targets

Abstract:

A metrology system may include a controller coupled to a metrology tool. The controller may receive a metrology target design including at least a first feature formed by exposing a first exposure field on a sample with a lithography tool, and at least a second feature formed by exposing a second exposure field on the sample with the lithography tool, where the second exposure field overlaps the first exposure field at a location of a metrology target on the sample. The controller may further receive metrology data associated with the metrology target fabricated according to the metrology target design, determine one or more fabrication errors during fabrication of the metrology target based on the metrology data, and generate correctables to adjust one or more fabrication parameters of the lithography tool in one or more subsequent lithography steps based on the one or more fabrication errors.