US 12,332,188 B2
High-performance EUV microscope with free form illumination system
Dong Gun Lee, Hwaseong-si (KR)
Assigned to ESOL, Inc., Hwaseong-si (KR)
Filed by ESOL, Inc., Hwaseong-si (KR)
Filed on May 26, 2023, as Appl. No. 18/202,301.
Claims priority of application No. 10-2022-0083995 (KR), filed on Jul. 7, 2022.
Prior Publication US 2024/0011922 A1, Jan. 11, 2024
Int. Cl. G01N 21/956 (2006.01); G03F 7/00 (2006.01)
CPC G01N 21/956 (2013.01) [G03F 7/70033 (2013.01); G03F 7/70983 (2013.01); G01N 2021/95676 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A high-performance EUV microscope with a free form illumination system, comprising:
an EUV light source that outputs EUV light;
one spherical mirror, which receives and reflects the EUV light outputted from the EUV light source and includes a two-axis drive part for controlling reflection direction of incident light through two-axis angle scan;
an optical path change means, which receives the reflected light reflected from the spherical mirror and provides illumination light to a measurement target;
a zone plate lens for focusing measurement light which is incident on the measurement target and then reflected; and
a photodetector for receiving the measurement light focused by the zone plate lens,
wherein reflection direction of reflected light is controlled by rotating the spherical mirror through the drive part, and illumination light irradiated onto the measurement target is controlled through the optical path change means on which the reflected light is incident,
wherein the optical path change means, which receives the reflected light reflected from the spherical mirror and provides illumination light to a measurement target, includes one plane mirror in which a plurality of mirror cells are arranged at each angle,
forms free form illumination light through the plane mirror,
allows the free form illumination to be incident on the measurement target, and
selectively controls a reflection angle of the spherical mirror and a reflection angle of the plane mirror, respectively, so as to control illumination light irradiated to the measurement target.