US 11,862,522 B2
Accuracy improvements in optical metrology
Barak Bringoltz, Rishon Le Tzion (IL); Evgeni Gurevich, Yoqneam Ylit (IL); Ido Adam, Qiriat Ono (IL); Yoel Feler, Haifa (IL); Dror Alumot, Rehovot (IL); Yuval Lamhot, Haifa (IL); Noga Sella, Migdal Haemek (IL); Yaron De Leeuw, Yehud (IL); Tal Yaziv, Kiryat Haim (IL); Eltsafon Ashwal-Island, Haifa (IL); Lilach Saltoun, Qiriat Ono (IL); and Tom Leviant, Yoqneam Illit (IL)
Filed by KLA-Tencor Corporation, Milpitas, CA (US)
Filed on Feb. 18, 2021, as Appl. No. 17/179,379.
Application 17/179,379 is a continuation of application No. 15/540,409, abandoned, previously published as PCT/US2017/019077, filed on Feb. 23, 2017.
Claims priority of provisional application 62/299,535, filed on Feb. 24, 2016.
Prior Publication US 2021/0175132 A1, Jun. 10, 2021
Int. Cl. H01L 21/66 (2006.01); G03F 7/00 (2006.01); G03F 9/00 (2006.01)
CPC H01L 22/20 (2013.01) [G03F 7/70633 (2013.01); G03F 9/7003 (2013.01); H01L 22/12 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An apparatus comprising:
an optical metrology tool that includes:
an optical illumination source;
optical elements;
a processing unit configured to:
select a plurality of measurement setups for a corresponding plurality of wafer regions, wherein the wafer regions are pre-determined or determined on-the-fly;
send instructions to carry out metrology measurements with one of the selected measurement setups for each corresponding wafer region using the optical metrology tool, wherein the metrology measurements are on a plurality of metrology targets on one or more wafers;
symmetrize pixel values in pupil images of the wafer regions;
modify at least one pixel value according to an average of neighboring pixel values thereby reducing noise in the pupil images;
concatenate pixels from the metrology measurements using a different one of the measurement setups;
determine metrology metric values from the concatenated pixels;
weight the concatenated pixels; and
determine measurement stability by comparing results from concatenations of different sub-sets of the metrology measurements.