An axisymmetric lens group structure for thermal effect correction of lithographic projection objective lens

Abstract

The invention relates to a non-axisymmetric lens group structure for lithography projection objective lens thermal effect correction and belongs to the deep ultraviolet lithography projection objective lens image quality compensation filed. The objective of the invention is to solve the problem of image quality deterioration which is caused by a situation in which materials absorb laser heat in the working process of a lithography projection objective lens, and in particular, problems of asymmetric multiplying power and constant term astigmatism which are brought about by a rectangular exposure field of view. The non-axisymmetric lens group structure for lithography projection objective lens thermal effect correction provided by the invention includes a lens frame, a non-axisymmetric structure and a lens; the non-axisymmetric structure consists of two identical fan-shaped areas; the two fan-shaped areas are in longitudinal symmetry and bilateral symmetry respectively; the lens frame is circumferentially and uniformly provided with a plurality of sets of flexible supporting units; the lens is fixedly connected with the plurality of sets of flexible supporting units on the lens frame in a gluing manner; the fan-shaped areas are fixed on the lens frame; gaps are left between the inner side walls of the fan-shaped areas and side wall of the lens; and installation directions of the fan-shaped areas are vertical to the scanning direction of the projection objective lens.

Description

technical field [0001] The invention belongs to the field of image quality compensation for deep ultraviolet lithography projection objects, and in particular relates to an axisymmetric mirror group structure used for correction of thermal effects of lithography projection objects. Background technique [0002] The lithography projection objective lens is one of the three core parts of the lithography machine. In order to meet the development needs of large-scale integrated circuits, the lithography projection objective lens needs to continuously improve its resolution and production efficiency. Improving the resolution of lithography is mainly achieved by shortening the exposure wavelength, reducing the process factor and increasing the numerical aperture of the lithography projection objective lens. At present, the widely used exposure wavelength in commercial production is 193nm, and the numerical aperture of the lithography projection objective lens has reached 1.35. As...

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Problems solved by technology

[0005] The purpose of the present invention is to propose an axisymmetric mirror group structure for correction of the thermal effect of the lithographic projection objective lens, which solves the problems in the prior art that the structure is complex and affects the imaging image quality during the imaging process, and avoids the problem of the lithographic projection objective lens in the working process. The problem of image quality degradation caused by the absorption of laser heat by the material, especially for the problem of asymmetric magnification and constant term astigmatism introduced by the rectangular exposure field of view

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