Imaging distortion calibration system and calibration method in interference measurement

Abstract

The invention relates to the technical field of optical detection, and especially relates to an imaging distortion calibration system in interference measurement. The imaging distortion calibration system in the interference measurement comprises an interference measurement apparatus, an adjustment mechanism, a crown grid plate and a data processing apparatus, wherein the crown grid plate is used for performing distortion calibration on a detected optical element; the adjustment mechanism adjusts the detected optical element to be disposed at a confocal interference detection position of the interference measurement apparatus, the center of the detected optical element, the geometric center of the crown grid plate and the optical axis of the interference measurement apparatus are superposed, and a coordinate axis of the crown grid plate is superposed with a coordinate axis of a detector of the interference measurement apparatus; the interference measurement apparatus carries out interference detection; and the data processing apparatus calculates a distortion function and a surface shape error of the detected optical element. The invention also provides an imaging distortion calibration method in interference measurement. According to the invention, through arrangement of the grid plate, imaging distortion calibration is carried out, and the technical effect of imaging distortion calibration is realized under the condition that the detected element is not damaged.

Description

Technical field [0001] The invention relates to the technical field of optical detection, in particular to a calibration method and a calibration system for imaging distortion in interferometry. Background technique [0002] Modern lithography technology requires the surface shape error of the plane, spherical, aspherical surface and other optical elements in the lithography objective lens system to reach the sub-nanometer level. Therefore, the lithography objective lens system has the surface processing and absolute detection technology for the optical elements. Put forward extremely high requirements. In order to achieve the sub-nanometer processing accuracy of the optical element surface shape, based on the sub-nanometer detection accuracy of the optical element surface shape error absolute detection technology, it is necessary to accurately calibrate the imaging distortion in the interferometric measurement used for the surface shape error detection, otherwise there will be i...

AI Technical Summary

Problems solved by technology

[0007] The present invention aims to overcome the technical defects of the existing detection system for in-situ detection of imaging distortion in interferometry, such as complex structure, low detection accuracy, and damage to the surface of the optical element to be inspected during calibration, and provides a detection system for imaging distortion in interferometry. Calibration system, including an interferometric device, an adjustment mechanism, a spherical cap grid plate and a data processing device, the spherical cap grid plate is distributed with marking holes and coordinate axes marked by the marking holes, the spherical cap The radius of curvature of the grid plate is the same as the radius of curvature of the inspected optical element, and is used for distortion calibration of the inspected optical element;

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