Apparatus for optical inspection includes a source of optical radiation,
which is adapted to scan a spot of the radiation over a sample, whereby the radiation
is scattered from the spot. A detection system includes at least first and second
detectors optically coupled to receive the scattered radiation and to generate
respective first and second outputs responsive thereto, the detection system being
configured so that the first detector detects variations in the scattered radiation
with a greater sensitivity than the second detector, while the second detector
saturates at a higher intensity of the scattered radiation than does the first
detector. A signal processor is coupled to receive the first and second outputs
and to determine, responsive to the outputs, locations of defects on the sample.
