Reflection-type photoetching projection objective

Abstract

The invention provides a reflection-type photoetching projection objective, which orderly comprises, in a light propagation direction: a first planar reflector, a first spherical reflector with a positive focal power, a second spherical reflector with a negative focal power, a third spherical reflector with a positive focal power, and a second planar reflector; the light propagation direction orderly passes through the first planar reflector, the first spherical reflector with a positive focal power, the second spherical reflector with a negative focal power, the third spherical reflector with a positive focal power, and the second planar reflector. The reflection-type photoetching projection objective of the invention has the following advantages: the exposure field of view is large, which is 500 mm in a non-scanning direction; multi-wavelength exposure is adopted, which increases the exposure illumination, and improves the yield of the photoetching machine; a 3-face reflector pure reflection structure is adopted, which provides the objective with extremely high transmittance, obtains excellent image quality with the proviso that the focal power of each reflector is reasonably distributed, and ensures important premises such as objective manufacture, cost, weight, and the like.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a reflective lithography projection objective lens applied to a semiconductor lithography device. Background technique [0002] Japanese patent JP4182304 discloses a lithography projection objective lens with a large exposure field of view, such as figure 1 As shown, the structure of the classic ofner reflector plus aberration-correcting lens is adopted. For the traditional offner structure, its shortcomings are obvious, and it is difficult to correct field curvature and astigmatism. If the aperture lens is enlarged to correct aberrations, better results can be achieved, but there will be problems in manufacturing feasibility and cost. In this example four glass lenses with a diameter of over 600mm are used. According to the data provided by the patent, this lithography objective has the following disadvantages: [0003] 1. The exposure field of view is sli...

AI Technical Summary

Problems solved by technology

[0004] 2. In order to ensure aberration, monochromatic light exposure is used, and the exposure efficiency is low;

[0005] 3. In order to improve the aberration, 2 to 4 large-diameter glass material lenses are used, which makes the manufacture of the objective lens more difficult, the cost is increased, and the weight is heavier

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