[6a-A414-1~10] 3.8 Optical measurement, instrumentation, and sensor

[6a-A414-1] Discrimination of subwavelength-size defects on a silicon substrate by polarization detection of laser scattered light

〇Yuta Urano¹, Toshifumi Honda¹ (1.Hitachi R&D Group)

Keywords:scattering, polarization, defect discrimination

For the purpose of improving accuracy of defect-type discrimination for semiconductor wafer surface inspection, a discrimination method with polarization detection of scattered light in multiple scattering directions was studied. Scattered distributions of defect models were simulated by DDA (Discrete Dipole Approximation) method, in order to estimate scattered intensities detected with detectors in multiple scattering directions. We analyzed scattering intensity and polarization distribution of defect models of two defect types, protrusions and particles, which had the same shapes and consisted of different materials, and found that polarization characteristics of side-scattered lights varied depending on defect types. As a result of evaluation with linear discriminant analysis using polarized and unpolarized scattering intensities as features, discrimination accuracy was improved by the use of polarized detection in direction of side-scattering in addition to unpolarized detection in multiple directions.