US 12,153,352 B2
System and method for focus control in extreme ultraviolet lithography systems using a focus-sensitive metrology target
Roel Gronheid, Leuven (BE); and Xuemei Chen, Austin, TX (US)
Assigned to KLA Corporation, Milpitas, CA (US)
Filed by KLA Corporation, Milpitas, CA (US)
Filed on Oct. 3, 2022, as Appl. No. 17/959,142.
Application 17/959,142 is a division of application No. 17/143,899, filed on Jan. 7, 2021, granted, now 11,460,783.
Prior Publication US 2023/0037093 A1, Feb. 2, 2023
Int. Cl. G03F 7/00 (2006.01); H01L 21/027 (2006.01)
CPC G03F 7/70641 (2013.01) [G03F 7/70625 (2013.01); G03F 7/70633 (2013.01); H01L 21/027 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A focus-sensitive metrology target comprising:
a first set of first target structures formed along a y-direction on one or more layers of a sample, the first set of first target structures comprising a plurality of segmented first pattern elements; and
a first set of second target structures formed along a y-direction on one or more layers of the sample, the first set of second target structures comprising a plurality of segmented second pattern elements, wherein one or more focus-offset values are determinable for the focus-sensitive metrology target based on illumination reflected or scattered from the first set of first target structures and the first set of second target structures by translating one or more signals indicative of the illumination into a focus-offset value using a calibration curve.