Pupil shaping unit structure of lithography machine and design method of diffractive optical element

Abstract

The invention discloses a pupil shaping unit structure of a lithography machine and a design method for a diffraction optical element of the pupil shaping unit structure. The pupil shaping unit structure comprises a cascade diffraction optical element and a varifocal collimating lens group, wherein the cascade diffraction optical element comprises a first diffraction optical element and a second diffraction optical element; the light transmittance surfaces of the two diffraction optical elements are perpendicular to the optical axis of a lighting system; the two diffraction optical elements are pure phase elements. The design method for the cascade diffraction optical element comprises the following steps of calculating a period of a phase unit; enabling a light beam to be incident, determining the light intensity distribution of the required optical beam and performing discretization processing; entitling initial phase matrixes of the first diffraction optical element and the second diffraction optical element; performing quantification processing through an iteration algorithm to obtain quantified phase matrixes of the first diffraction optical element and the second diffraction optical element; evaluating a design result.

Description

technical field [0001] The invention relates to a lithography machine, in particular to a pupil shaping unit structure of a lithography machine and a design method for a diffractive optical element thereof. Background technique [0002] In the lighting system of the lithography machine, it is necessary to adopt an off-axis lighting mode to enhance the resolution of the lithography, increase the depth of focus, and improve the contrast of the lithography pattern, thereby improving the quality of the lithography pattern. The pupil shaping unit in the lighting system of the lithography machine needs to provide traditional lighting (that is, on-axis lighting mode), and off-axis lighting modes such as ring lighting, dipole lighting, and quadrupole lighting. The diffractive optical element (Diffractive Optical Element, referred to as DOE) in the pupil shaping unit cooperates with the zoom collimator lens group to realize the various illumination modes described above. DOE has the...

AI Technical Summary

Problems solved by technology

This method is to use optical fiber to split the laser beam. However, due to the large divergence angle of the output beam of the optical fiber, it will cause the collapse of the light field when irradiated by the diffractive optical element, which will affect the non-uniformity of the illumination pupil, so it cannot be applied Actual deep ultraviolet lithography machine illumination system

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