High-resolution Forbes aspherical photoetching objective lens

Abstract

The invention relates to a high-resolution Forbes aspherical photoetching objective lens, and belongs to the technical field of high-resolution projection photoetching objective lenses. The high-resolution Forbes aspherical photoetching objective lens specifically comprises a front lens group and a rear lens group, wherein the numerical aperture is 0.75, and totally 29 lenses are used; the surfaces of six lenses are Forbes aspherical surfaces; the lenses are made of fused quartz and calcium fluoride; the calcium fluoride is used for correcting chromatic aberration; the front lens group and the rear lens group are fixedly connected together at a certain interval through a mechanical component on a lens outer frame; and the two lens groups share the same optical axis. According to the high-resolution Forbes aspherical photoetching objective lens, the resolution of the conventional projection photoetching objective lens is improved, and the effectiveness of each aspherical surface and each aspherical coefficient is guaranteed, so that the number of the aspherical surfaces and the number of effective figures of the system are reduced and the image quality is improved at the same time, and the tolerance sensitivity is reduced greatly; when a central light ray is used as a reference, single-color root-mean-square wave aberration is less than 0.5 nanometers, and the distortion is less than 0.5 nanometers; and the high-resolution Forbes aspherical photoetching objective lens can be applied to a deep ultraviolet projection photoetching device, in which the wavelength of a lighting light source is 193 nanometers.

Description

technical field [0001] The invention relates to a high-resolution Forbes aspheric lithography objective lens, belonging to the technical field of high-resolution projection lithography objectives. Background technique [0002] Photolithography is an integrated circuit manufacturing technology that uses optical methods to transfer the circuit pattern on the mask plate to the silicon wafer. Almost all integrated circuits are manufactured using optical lithography. [0003] With the development of time, lithography machines have successively experienced contact type, proximity type, full-silicon wafer scanning projection type, step-and-repeat projection type, and the current step-scan projection type. Then the exposure wavelength is reduced from 436nm (g-line), 365nm (i-line), 48nm (KrF) to the current common 193nm (ArF), even to extreme ultraviolet light of 157nm, and extreme ultraviolet light of 13.5nm wavelength. Since the 1960s, most of the objective lenses in lithography ...

AI Technical Summary

Problems solved by technology

[0006] In order to further improve the imaging quality and solve the problems of many aspheric surfaces and high tolerance sensitivity of the Forbes aspheric lithography objective lens in the prior art, the present invention proposes a high-resolution Forbes aspheric lithography objective lens

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