US 11,727,556 B2
Defect detection for multi-die masks
Wenfei Gu, Milpitas, CA (US); Pei-Chun Chiang, Cupertino, CA (US); and Weston Sousa, San Jose, CA (US)
Assigned to KLA Corp., Milpitas, CA (US)
Filed by KLA Corporation, Milpitas, CA (US)
Filed on Sep. 29, 2021, as Appl. No. 17/489,665.
Prior Publication US 2023/0098730 A1, Mar. 30, 2023
Int. Cl. G06K 9/00 (2022.01); G06T 7/00 (2017.01); G06T 7/80 (2017.01); G03F 7/00 (2006.01); G06F 16/50 (2019.01); G03F 1/84 (2012.01)
CPC G06T 7/001 (2013.01) [G03F 1/84 (2013.01); G03F 7/7065 (2013.01); G06F 16/50 (2019.01); G06T 7/0006 (2013.01); G06T 7/80 (2017.01); G06T 2207/30148 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A system configured for detecting defects on a mask, comprising:
an imaging subsystem configured to generate images of a mask having multiple dies formed thereon; and
a computer subsystem configured for:
generating a database reference image for the mask by simulating a physical version of the mask from a design for the mask and simulating an image of the physical version of the mask generated by the imaging subsystem from the simulated physical version of the mask;
detecting first defects on the mask by comparing the database reference image to the images of the mask generated by the imaging subsystem for a first of the multiple dies;
generating a die reference image for the first of the multiple dies by applying one or more parameters of the imaging subsystem learned by generating the database reference image to the images generated by the imaging subsystem of one or more of the multiple dies other than the first of the multiple dies; and
detecting second defects on the mask by comparing the die reference image to the images of the mask generated by the imaging subsystem for the first of the multiple dies.