Optical inspection system for semiconductor wafers

摘要

A method and apparatus for automatically detecting defects on the surfaces of semiconductor wafers and chips which provides a 100% inspection capability. The entire surface of each wafer is scanned by use of a low magnification, low resolution detector such as a photodiode array. Whenever a defect occurs, encoders on the supporting XY table are triggered, such that the location of a defect on the wafer is recorded. After the event coordinates have been determined, the XY table positions each defect directly under a high magnification detector to determine the nature of the detected event. Since only the locations of the detected events are stored, 100% of the processed wafers can be scanned for defects.