High-resolution projection optical system

Abstract

The invention provides a high-resolution projection optical system which is used for imaging the image of an object plane into an image plane. The high-resolution projection optical system comprises a first lens unit (L1), a second lens unit (L2), a third lens unit (L3) and a fourth lens unit (L4) along the direction of an optical axis. Being sequentially lined from the incident direction of a light beam, the first lens unit (L1) is provided with negative refractive force, the second lens unit (L2) is provided with positive refractive power, the third lens unit (L3) is provided with negative refractive force, and the fourth lens unit (L4) is provided with positive refractive force. The projection optical system contains four aspheric surfaces. According to the high-resolution projection optical system, the image quality is better, the total length is shortened, the aperture diameter of lenses are reduced, and the resolution of the system is improved.

Description

technical field [0001] The invention relates to a deep ultraviolet projection optical system used in a lithography process and a semiconductor element manufacturing device, and belongs to the technical field of high-resolution projection optical systems. Background technique [0002] Lithography is an integrated circuit manufacturing technology. It uses the principle of optical projection image to transfer the high-resolution IC pattern on the mask plate to the rubber-coated silicon wafer by exposure. Almost all integrated circuits are manufactured using optical projection. Photolithography. Initially, semiconductor devices were manufactured using contact lithography technology in which masks were attached to silicon wafers. In 1957, contact lithography technology realized the manufacture of DRAM (Dynamic Random Access Memory) with a feature size of 20 μm. After that, the semiconductor industry introduced proximity lithography technology with a certain gap between the mask...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problems of low resolution, long system length, large lens diameter and difficult installation and adjustment of the existing projection optical system, the present invention proposes a high-resolution projection optical system. The light source of the illumination system adopts ArF excimer laser. The wavelength is 193nm, and the numerical aperture reaches 0.75. The high-resolution projection optical system has a compact structure, only contains 4 aspherical surfaces, small lens aperture, and good imaging quality, which effectively reduces the system cost and installation difficulty.

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