Patent ID: 7522293
Filing Date: 2009-04-21
Classification: G01B,G01N

Abstract:
1. A method of determining one or more features of multiple patterned layers formed on a semiconductor wafer, the method comprising: a) obtaining a first measured diffraction signal measured from a first patterned layer before a second patterned layer is formed on top of the first patterned layer; b) determining one or more features of the first patterned layer using the first measured diffraction signal obtained in a); c) fixing values of one or more profile parameters of a hypothetical profile of the second patterned layer in combination with the first patterned layer; d) obtaining a second measured diffraction signal measured from the second patterned layer after the second patterned layer has been formed on top of the first patterned layer; and e) determining one or more features of the second patterned layer based on the second measured diffraction signal and the fixed values of the one or more profile parameters in c).