Disclosed is a method of inspecting a sample. The sample is scanned in
a first direction with at least one particle beam. The sample is scanned in a second
direction with at least one particle beam. The second direction is at an angle
to the first direction. The number of defects per an area of the sample are found
as a result of the first scan, and the position of one or more of the found defects
is determined from the second scan. In a specific embodiment, the sample includes
a test structure having a plurality of test elements thereon. A first portion of
the test elements is exposed to the beam during the first scan to identify test
elements having defects, and a second portion of the test elements is exposed during
the second scan to isolate and characterize the defect.