Patent ID: 7324193
Filing Date: 2008-01-29
Classification: G01N,H01L

Abstract:
1. A method of measuring a damaged structure formed on a semiconductor wafer using optical metrology, the method comprising: obtaining a measured diffraction signal from a damaged periodic structure; defining a hypothetical profile of the damaged periodic structure, the hypothetical profile having an undamaged portion, which corresponds to an undamaged area of a first material in the damaged periodic structure, and a damaged portion, which corresponds to a damaged area of the first material in the damaged periodic structure, and wherein the undamaged portion and the damaged portion have different properties associated with them; calculating a simulated diffraction signal for the hypothetical damaged periodic structure using the hypothetical profile; comparing the measured diffraction signal to the simulated diffraction signal; and if the measured diffraction signal and the simulated diffraction signal match within a matching criterion, establishing a damage amount for the damaged periodic structure based on the damaged portion of the hypothetical profile used to calculate the simulated diffraction signal.