US 11,880,142 B2
Self-calibrating overlay metrology
Stilian Pandev, Santa Clara, CA (US); Min-Yeong Moon, Ann Arbor, MI (US); Andrei V. Shchegrov, Campbell, CA (US); Jonathan Madsen, Los Altos, CA (US); Dimitry Sanko, Vallejo, CA (US); Liran Yerushalmi, Zicron Yaacob (IL); Alexander Kuznetsov, Milpitas, CA (US); and Mahendra Dubey, Milpitas, CA (US)
Assigned to KLA Corporation, Milpitas, CA (US)
Filed by KLA Corporation, Milpitas, CA (US)
Filed on Mar. 7, 2023, as Appl. No. 18/118,420.
Application 18/118,420 is a continuation of application No. 17/488,010, filed on Sep. 28, 2021, granted, now 11,604,420.
Claims priority of provisional application 63/214,573, filed on Jun. 24, 2021.
Claims priority of provisional application 63/183,075, filed on May 3, 2021.
Prior Publication US 2023/0221656 A1, Jul. 13, 2023
Int. Cl. G03F 7/00 (2006.01)
CPC G03F 7/70633 (2013.01) [G03F 7/70516 (2013.01); G03F 7/70775 (2013.01)] 34 Claims
 
1. A self-calibrating overlay metrology system comprising:
a controller including one or more processors configured to execute program instructions causing the one or more processors to:
receive device overlay data for a plurality of device targets on a sample from an overlay metrology tool;
determine preliminary device overlay measurements for the plurality of device targets including device-scale features using an overlay recipe with the device overlay data as inputs;
receive assist overlay data for one or more assist targets on the sample including device-scale features from the overlay metrology tool, wherein at least one of the one or more assist targets has a programmed overlay offset of a selected value along a particular measurement direction;
determine self-calibrating assist overlay measurements for the one or more assist targets based on the assist overlay data, wherein the self-calibrating assist overlay measurements are linearly proportional to overlay on the sample; and
generate corrected overlay measurements for the plurality of device targets by adjusting the preliminary device overlay measurements based on the self-calibrating assist overlay measurements.