Method for improving measurement precision of beam polarization degree

Abstract

The invention relates to a method for improving measurement precision of a beam polarization degree. A utilized polarization detection device comprises a phase delay device, an analyzer and a photo detector which are sequentially arranged along an optical axis of a system of the device, wherein the output of the photo detector is connected with a signal processing system, a beam to be measured which is parallel to the optical axis of the system is emitted to the phase delay device and the analyzer and detected by the photo detector, and the electric signal output by the photo detector is sent to the signal processing system for data processing. The method is characterized in that the transmission axis direction of the analyzer and the polarization direction of the beam to be measured are adjusted to be parallel or vertical according to the polarization direction of the beam to be measured, and then the measurement of the polarization degree of the beam to be measured is carried out. A stokes parameter and the polarization degree of the beam to be measured are obtained according to the light intensity detected by the photo detector. The invention can improve the measurement precision of the polarization degree.

Description

technical field [0001] The invention relates to the detection of the degree of polarization of light beams, in particular to a method for improving the measurement accuracy of the degree of polarization of light beams. Background technique [0002] The progress of semiconductor manufacturing technology is always driven by the reduction of exposure wavelength, the increase of numerical aperture of projection objective lens and the reduction of lithography process factor k1. In recent years, immersion lithography technology has achieved rapid development. In immersion lithography technology, a certain liquid is used to fill between the last lens of the objective lens and the photoresist on the silicon wafer, so that the numerical aperture of the projection objective lens is significantly improved. When the numerical aperture of the projection objective lens of the lithography machine is close to 0.8 or larger, the influence of the polarization of the illumination light on the...

AI Technical Summary

Problems solved by technology

However, this method cannot measure the positioning error between the fast axis direction of the phase delay device and the direction of the polarizer transmission axis after the polarization detection device is formed.

Therefore, when there are positioning errors of the fast axis of the phase delay device and the positioning error of the transmission axis of the analyzer in the polarization detection device, the measurement results of the degree of polarization will still be affected.

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