A critical-like illumination system for extreme ultraviolet lithography

Abstract

The invention relates to a type critical illumination system for extreme ultra-violet lithography, belonging to the field of a critical illumination system in an extreme ultra-violet lithography system. The type critical illumination system comprises a light condensing system, a relay system, a photoetching system vacuum tank body and a corrugated pipe, wherein the light condensing system comprises a light source, a light condensing primary mirror, a light condensing system secondary mirror, a scrap removing system and a light condensing system vacuum tank body; the scrap removing system is arranged on a symmetry axis of a light source emergent sector along a light path; the light condensing system secondary mirror and the light condensing primary mirror are sequentially arranged behind the scrap removing system, and the light source, the light condensing system secondary mirror and the light condensing primary mirror commonly form a Schwartz-Kierard system; the light condensing system secondary mirror and the light condensing primary mirror are both arranged in the light condensing system vacuum tank body; the front end of the scrap removing system is close to the light source, and the rear end of the scrap removing system is fixedly connected with the rear end of the light condensing system secondary mirror. According to the type critical illumination system, the light source collecting solid angle can reach 0.48Sr, the shielded center area is less than 25%, the luminous energy collecting efficiency is greatly improved, an effective action distance of the scrap removing system can be increased and the scrap removing effect can be well achieved.

Description

technical field [0001] The invention belongs to the field of critical illumination systems in extreme ultraviolet lithography systems, and in particular relates to a quasi-critical illumination system for extreme ultraviolet lithography. Background technique [0002] The optical main structure of the lithography system usually includes two parts: the illumination system and the objective lens system, such as figure 2 As shown, the existing objective lens system 3 includes a mask surface 30, a primary mirror 31 of the objective lens system 3 (that is, the entrance pupil of the objective lens system 3), a secondary mirror 32 of the objective lens system 3, and a wafer surface 33. After the illumination light is sequentially reflected by the mask surface 30, the primary mirror 31 of the objective lens system 3 and the secondary mirror 32 of the objective lens system, the pattern on the mask surface 30 is finally projected on the wafer surface 33 and etched. . [0003] The lig...

AI Technical Summary

Problems solved by technology

[0011] In order to solve the problem that the existing classical critical lighting system is only suitable for pure-spectrum light sources, it lacks a secondary vacuum isolation system that allows the light path to pass through, an extreme ultraviolet light filter and transmission film, and an effective space for the dandruff removal system, so it cannot be directly used to construct an extreme lighting system. Ultraviolet lithography system, at the same time, the lighting system and objective lens system used by it are too compact and irregular in layout, which increases the difficulty of processing various components and the difficulty of later assembly and calibration

On the other hand, the existing conventional blocking devices cannot change the position, angle and effective blocking area in the light path, and do not have the technical problem of continuously adjusting the uniformity of illumination in the light path. The present invention provides an extreme ultraviolet Critical Illumination System for Lithography

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