Patent ID: 6639663
Filing Date: 2003-10-28
Classification: G01N

Abstract:
A method for characterizing a misprocessed wafer, comprising:providing a wafer having a grating structure; illuminating at least a portion of the grating structure; measuring light reflected from the grating structure to generate a reflection profile; comparing the generated reflection profile to a library of reference reflection profiles, each reference reflection profile having an associated characteristic; determining if the generated reflection profile correlates with any of the reference reflection profiles; identifying a misprocessed condition of the wafer in response to the generated reflection profile not correlating with any of the reference reflection profiles; comparing the generated reflection profile to a fault classification library of reflection profiles, each reference reflection profile having an associated processing fault; selecting a reflection profile closest to the generated reflection profile; and characterizing the misprocessed condition of the wafer based on the processing fault associated with the selected reflection profile.