Patent ID: 7859659
Filing Date: 2010-12-28
Classification: G01B,G01N,G03F,H01L

Abstract:
1. A method for measuring one or more parameters of a sample, said sample including a plurality of periodic diffracting structures and an associated structure, said associated structure having a thickness and an optical index, wherein said plurality of periodic diffracting structures and the associated structure are located on a common substrate, comprising: measuring an optical index and a film thickness of the associated structure; constructing a reference database of one or more parameters related to said diffracting structures using said optical index and film thickness of the associated structure; directing a beam of electromagnetic radiation of a plurality of wavelengths at each of said plurality of periodic diffracting structures; detecting a diffraction at said plurality of wavelengths of said beam from each of said plurality of periodic diffracting structures; obtaining intensity data or ellipsometric parameter values corresponding to each of said plurality of periodic diffracting structures from the detected diffraction; and comparing said obtained intensity data or ellipsometric parameter values corresponding to each of said plurality of periodic diffracting structures to said database to determine said one or more parameters of said plurality of periodic diffracting structures.