On-line detection device of wave aberration of projection lens of lithography machine with precision calibration function

Abstract

The invention relates to an on-line detection device of wave aberration of a projection lens of a lithography machine with precision calibration function, which belongs to the field of optical detection. The on-line detection device additionally introduces a grating and two circular holes in a PSPDI by utilizing the property that the system error of the PSPDI rotates along with the beam splitting direction of the grating, the two gratings and the three circular holes are taken as measurement precision calibration elements together, and the system error during the calibration of the measurement precision of the PSPDI is separated according to the orthogonal property and the odd-even symmetry property of a Zernike polynomial in the unit circular region, thereby obtaining the wave surface error of a spherical reference wave produced by diffraction of the circular holes for calibration and characterization of the measurement precision of the PSPDI and leading the on-line detection device of the projection lens of the lithography machine to have the capability of realizing the on-line detection of the wave aberration and also have the measurement precision calibration function.

Description

technical field The invention relates to an on-line detection device for wave aberration of a projected objective lens of a lithography machine with the function of calibrating measurement precision, and belongs to the field of optical detection. Background technique The projection exposure device is used in the preparation process of large-scale integrated circuits, and the pattern on the mask is reduced and projected on the silicon wafer coated with photoresist through the projection objective lens. The 2007 International Semiconductor Technology Roadmap (ITRS2007) pointed out that extreme ultraviolet lithography (EUVL) is the most potential candidate technology to achieve 32nm and below technology nodes. Related patent 1 (US5835217) proposes a phase-shifting point diffraction interferometer (PSPDI) installed on an EUVL lithography machine and using the exposure wavelength to detect the wave aberration of the projection objective lens online. Patent 1 points out that, ac...

AI Technical Summary

Problems solved by technology

The purpose of the present invention is to improve the structure of PSPDI for the problem that the system error cannot be completely separated when the existing method is used to calibrate the measurement accuracy of PSPDI, and to add measurement accuracy calibration components in PSPDI, and to propose a projection objective lens with measurement accuracy calibration function Wave aberration online detection device

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