Elliptical polarization characterization of scattered light in dark field defect inspection technology

In the field of unpatterned wafer inspection, the biggest market share is dark field defect inspection, in which the signalto-noise ratio limits the detection limit. In order to improve the signal-to-noise ratio of the optical detection method based on the theory of dark-field scattered light. In this paper, the influence of the polarization characteristic of light on the scattering field is studied, and the signal-to-noise ratio of the scattering signal can be improved by controlling the polarization component of light. The results show that modulating the polarized light can achieve a higher signal-to-noise ratio.