Patent ID: 6292259
Filing Date: 2001-09-18
Classification: G01N,H01L

Abstract:
A surface inspection system for distinguishing between particle defects and pit defects on a surface of a workpiece comprising:an inspection station for receiving the workpiece;a scanner positioned to scan a surface of the workpiece at the inspection station, the scanner including a light source arranged to project p-polarized light at an angle of incidence oblique to the workpiece surface;a first collector positioned to collect light scattered from the surface of the workpiece at a central zone;a second collector positioned to collect light scattered from the surface of the workpiece at an oblique zone offset angularly from the central zone;one or more converters for converting the collected light components into respective signals representative of the light scattered into the central zone and oblique zone; anda system controller configured to receive the signals, compare the signals, and classify defects as pits or particles based at least in part on the comparison.