248nm deep ultraviolet high numerical aperture Kohler illumination bunching lens

Abstract

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.

Description

technical field [0001] The invention relates to a deep ultraviolet micro-illumination beam focusing lens, which belongs to the technical field of illumination beam focusing of an integrated circuit reticle detection device. This device is mainly used in the 248nm-380nm band, especially for 248nm, 266nm and 365nm wavelength ultraviolet and deep ultraviolet microscopes to provide low stray light, uniform brightness and high numerical aperture illumination field of view. Background technique [0002] The deep ultraviolet microscope is an important detection equipment for photolithography masks with line widths above 100nm, MEMS / NEMS devices and other two-dimensional nano-geometric structure samples. The beamforming mirror is one of the core components in which the sample is illuminated and the resolution is improved. At present, the most common ultraviolet microscope usually uses a 365nm illumination source. With the development of microelectronic integrated circuits, its dete...

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Problems solved by technology

[0008] In view of the fact that the existing deep ultraviolet microscope does not have a 248nm transmission illumination beamforming optical system and cannot provide an illumination light source with a large numerical aperture, thereby affecting the imaging resolution, the present invention proposes a deep ultraviolet high numerical aperture Kohler illumination beamforming lens, which can Realize the transmission of 248nm deep ultraviolet light, and provide a uniform illumination field of view with a field of view of D=50μm and a numerical aperture of 0.67

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