Patent ID: 8250497
Filing Date: 2012-08-21
Classification: G03F,G06F

Abstract:
1. A method for measuring an overlay error using a system having an angular scatterometer, a data processing module, a matching unit and a database, and using a computer system, the method comprising the steps of: providing a two-dimensional array overlay target set to be measured, wherein the step of providing the two-dimensional array comprises: measuring diffraction spectra of the two-dimensional array overlay target set to be measured using the angular scatterometer; calculating a root mean square error of the measured diffraction spectra of the two-dimensional array overlay target set to be measured using the data processing module; performing a matching process to find a root mean square error in the database matched with the root mean square error of the measured diffraction spectra of the two-dimensional array overlay target set to be measured using the matching unit; and determining a first-dimensional overlay error and a second-dimensional overlay error of the two-dimensional array overlay target set to be measured in accordance with the matched root mean square error using the matching unit.