Patent ID: 11874102
Assignee: KLA CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A metrology target comprising:
a first target structure configured in accordance with a metrology recipe, wherein the first target structure is formed within at least one of a first area and a third area of a first layer of a sample, the first target structure comprising two or more first cells each containing two or more first cell pattern elements arranged periodically; and
a second target structure configured in accordance with the metrology recipe, wherein the second target structure is formed within at least one of a second area and a fourth area of a second layer of the sample, the second target structure comprising two or more second cells containing two or more second cell pattern elements arranged periodically, wherein the second target structure is formed from a photoresist material with sufficient thickness to induce asymmetry in at least some of the second cell pattern elements when fabricated in accordance with the metrology recipe, wherein at least one of a size or a number the second cell pattern elements is selected in accordance with the metrology recipe to provide that an overlay value for the metrology target mitigates the asymmetry in the at least some of the second cell pattern elements when the overlay value is determined in accordance with the metrology recipe based on one or more images of the metrology target from an optical metrology tool by computing a difference between a center of gravity of the first layer and a center of gravity of the second layer based on averaged individual center of gravity values of each of the first cell pattern elements and the second cell pattern elements.