248nm deep ultraviolet high numerical aperture Kohler illumination bunching lens

• Main Authors: WANG HEQUN, LI WEI, LI SHI, LI QI, GAO SITIAN, SHI YUSHU
• Format: Patent
• Language: English
• Published: 26.08.2015
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

The invention provides a 248nm deep ultraviolet high numerical aperture Kohler illumination bunching lens comprising a front part relay lens group and a rear part imaging lens group which are arranged in the same optical axis. The front part relay lens group is composed of first to third lenses which are arranged in turn in a front-and-back direction. The rear part imaging lens group is composed of fourth to twelfth lenses which are arranged in turn in the front-and-back direction. The twelfth lens is a parallel plate lens through which deep ultraviolet light rays can be transmitted, and the twelfth lens can also be used for supporting a measured sample. The two lens groups are installed in a constant temperature sealed sleeve. Each lens is installed in a corresponding lens frame. The high numerical aperture Kohler illumination design is adopted so that the 248nm deep ultraviolet high numerical aperture Kohler illumination bunching lens has advantages that brightness is uniform without introduction of light source artifacts, image aberration is optimized and stray light is suppressed, and thus extremely high resolution is guaranteed by the high numerical aperture. The experiment proves that the clear outline image of 100nm line width can be generated by the 248nm deep ultraviolet high numerical aperture Kohler illumination bunching lens under an ultraviolet microscope so that the 248nm deep ultraviolet high numerical aperture Kohler illumination bunching lens is suitable for illumination of detection of the key size of integrated circuit photo-etching mask plates, nano geometric structure grids and MEMS/NEMS devices.