Conventionally, a particle/defect inspection apparatus outputs a
total number of detected particles/defects as the result of detection. For taking
countermeasures to failures in manufacturing processes, the particles/defects detected
by the inspection apparatus are analyzed. Since the inspection apparatus outputs
a large number of detected particles/defects, an immense time is required for analyzing
the detected particles/defects, resulting in a delay in taking countermeasures
to a failure in the manufacturing processes. In the present invention, an apparatus
for optically inspecting particles or defects relates a particle or defect size
to a cause of failure in an inspection result. A data processing circuit points
out a cause of failure from the statistics on the inspection result, and displays
information on the inspection result. A failure analysis is conducted by setting
a threshold for identifying a failure in each of regions on a semiconductor device
or the like to statistically evaluate detected particles.