Defect inspection method and apparatus therefor

摘要

To effectively utilize the polarization property of an inspection subject for obtaining higher inspection sensitivity, for the polarization of lighting, it is necessary to observe differences in the reflection, diffraction, and scattered light from the inspection subject because of polarization by applying light having the same elevation angle and wavelength in the same direction but different polarization. According to conventional techniques, a plurality of measurements by changing polarizations is required to cause a prolonged inspection time period that is an important specification of inspection apparatuses. In this invention, a plurality of polarization states are modulated in micro areas in the lighting beam cross section, images under a plurality of polarized lighting conditions are collectively acquired by separately and simultaneously forming the scattered light from the individual micro areas in the individual pixels of a sensor, whereby inspection sensitivity and sorting and sizing accuracy are improved without reducing throughput.

主权项

1. An inspection method comprising:
illuminating a sample to be inspected with light emitted from a lighting unit; detecting light scattered from a portion illuminated by the light with an imager having a plurality of detection pixels; and processing a signal output from the imager by the detection of the scattered light with a signal processor to detect a defect on the sample, wherein in the step of illuminating, the light illuminates a plurality of small regions on the sample to which the light illuminates under different polarization conditions by the small regions; wherein in the step of detecting, the imager detects light scattered from each of the small regions, which are illuminated under the different polarization conditions by the step of illuminating, with different pixels; and wherein in the step of processing, the signal processor processes a detected signal in each of the small regions under the different polarization conditions detected at the different pixels in the step of detecting and detects a defect on the sample.