Projection optical system

Abstract

The invention provides a projection optical system. A first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group are sequentially arranged along the direction of an optical axis of the projection optical system and located on the same optical axis. The first lens group and the third lens group are provided with negative focal power. The second lens group, the fourth lens group and the fifth lens group are provided with positive focal power. The first lens group receives input light beams and outputs first divergent beams; the second lens group receives the first divergent beams and output second divergent beams; the third lens group receives the second divergent beam and output first convergent beams; the fourth lens group receives the first convergent beams and outputs third divergent beams; and the fifth lens group receives the third divergent beams, outputs second convergent beams, and converges the second convergent beams to an image surface. On the condition of high resolutions and high numerical apertures, the projection optical system effectively reduces the number of lenses, reduces cost of processing, detecting and adjusting, and provides relatively large object space and image space working distances at the same time.

Description

technical field [0001] The invention relates to a projection optical system in a photolithography system, in particular to a high-resolution projection optical system. Background technique [0002] Since the advent of the integrated circuit IC in the 1970s, it has experienced a development stage from small-scale to ultra-large-scale, and its progress has benefited from the rapid development of lithography. Photolithography is one of the most important processes in the manufacture of large-scale integrated circuits. The exposure equipment used in lithography accurately projects the pattern on the mask onto the silicon wafer coated with photoresist through the projection optical system in a step-by-step repeating or scanning manner. Exposure is carried out, and the quality of the exposure has a great influence on the subsequent development, etching, and glue removal processes. With the development of integrated circuit manufacturing, the resolution requirements of the project...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problems of too many lenses in the projection optical system, large wave aberration RMS and distortion, small numerical aperture, and too short object-space working distance and image-space working distance in the existing technical solutions, the purpose of the present invention is to provide a A projection optical system with fewer lenses, smaller wave aberration RMS and distortion, and larger numerical aperture

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