Patent ID: 6785638
Filing Date: 2004-08-31
Classification: G01B,G01N

Abstract:
A method of determining a first actual profile associated with a first grating comprising:receiving a set of measurements associated with a signal indicative of diffraction from the grating; generating a first actual spectrum signal data associated with the grating; selecting a first trial profile; generating a first trial spectrum signal data associated with the first trial profile; comparing the first trial spectrum signal data to the first actual spectrum signal data; determining parameter values for a second trial profile using at least one optimization technique based on the comparison of the first trial spectrum signal data to the first actual spectrum signal data, wherein the second trial profile is associated with a second sample trial spectrum signet data, and wherein the second trial profile matches the first actual profile more closely than the first trial profile; and storing the second trial profile and the second sample trial spectrum signal data in a dynamic library of profiles.