| CPC G03F 7/70116 (2013.01) [G03F 7/70075 (2013.01); G03F 7/702 (2013.01)] | 8 Claims |
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1. A high performance EUV microscope device with a freeform illumination system having an elliptical mirror comprising:
an EUV source for outputting EUV light;
a spherical mirror having a two-axis driving unit which receives and reflects the EUV light output from the EUV light source and controls a reflection direction of the incident light through two-axis angle scanning;
an optical path changing means for receiving the reflected light reflected from the spherical mirror and providing illumination light to a target object to be measured, wherein the optical path changing means comprises:
one plane mirror receiving the reflected light reflected from the spherical mirror to determine an angle of the illumination light provided to the target object to be measured; and
an elliptical mirror forming freeform illumination light through the plane mirror to be incident to the target object,
a zone plate lens for focusing the light reflected after entering the target object; and
a photodetector for receiving the light focused by the zone plate lens,
wherein the spherical mirror is rotated by the driving unit to control the reflection direction of the reflected light, and the illumination light irradiated to the target object is controlled by the optical path changing means receiving the reflected light,
wherein the optical path changing means selectively controls a reflection angle of the spherical mirror and a reflection angle of the plane mirror to determine a reflection angle,
wherein in order to have a uniform intensity distribution of the illumination light irradiated to the target object to be measured, the plane mirror controls the angle of the spherical mirror in a fixed state so as to control the intensity distribution of the illumination light, and wherein in order to determine an incident angle distribution of the illumination light irradiated to the target object, the spherical mirror controls the angle of the plane mirror in a fixed state so as to control the incident angle of the illumination light,
wherein the elliptical mirror is designed such that the illumination light having a plurality of optical axes incident through the plane mirror has reflection characteristics to enter the same position of the target object, so that the illumination light enters the same position of the target object even in a case of entering with multiple optical axes, and wherein the incident angle of light entering the target object is determined according to the position that the illumination light reflected from the plane mirror enters the elliptical mirror.
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