US 12,460,991 B2
Photomask inspection apparatus and method of inspecting photomask using the same
Chanhyeong Cho, Yongin-si (KR); Tae Joon Kim, Yongin-si (KR); Jeongmin Park, Yongin-si (KR); Hyeonguk Yeo, Yongin-si (KR); Juil Kim, Incheon (KR); and Daehoon Min, Incheon (KR)
Assigned to SAMSUNG DISPLAY CO., LTD., Gyeonggi-do (KR); and HIMS CO., LTD., Incheon (KR)
Filed by Samsung Display Co., Ltd., Yongin-si (KR); and HIMS CO., LTD., Incheon (KR)
Filed on Jul. 24, 2023, as Appl. No. 18/225,534.
Claims priority of application No. 10-2022-0097829 (KR), filed on Aug. 5, 2022.
Prior Publication US 2024/0044741 A1, Feb. 8, 2024
Int. Cl. G01M 11/02 (2006.01); G03F 7/00 (2006.01)
CPC G01M 11/0257 (2013.01) [G03F 7/70441 (2013.01); G03F 7/7065 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A photomask inspection apparatus comprising:
a stage which supports an inspection substrate;
a first optical system having a first numerical aperture and disposed at one side of the inspection substrate;
a second optical system having a second numerical aperture, spaced apart from the first optical system, and disposed at the one side of the inspection substrate;
an imaging optical system comprising a first objective lens aligned with the first optical system with the inspection substrate disposed therebetween, a second objective lens aligned with the second optical system with the inspection substrate disposed therebetween, and disposed at another side of the inspection substrate, which is opposite to the one side of the inspection substrate; and
a camera which captures an image passed through the imaging optical system,
wherein the first numerical aperture is greater than the second numerical aperture.