Patent Document ID: 8773657
Application ID: 10590352
Patent Flag: 1

Claim One:
1. A method for determining at least one process parameter in a device manufacturing process, the method comprising: obtaining calibration spectral measurement data from a plurality of calibration marker structure sets provided on a calibration object, each of said plurality of calibration marker structure sets comprising at least one calibration marker structure, calibration marker structures of different calibration marker structure sets being created using different known values of said at least one process parameter; determining a mathematical model by using said known values of said at least one process parameter and by employing a multi-variant regression technique on said calibration spectral measurement data, said mathematical model comprising a number of regression coefficients; obtaining spectral measurement data from at least one marker structure provided on an object, said at least one marker structure being made using an unknown value of said at least one process parameter; comparing the obtained spectral measurement data with the calibration spectral measurement data to determine the unknown value of said at least one process parameter for said object from said obtained spectral measurement data by employing said regression coefficients of said mathematical model; and adjusting a control parameter of a lithographic apparatus based on the unknown value of said at least one process parameter for said object in the device manufacturing process; wherein the multi-variant regression technique used by the mathematical model is selected from a group consisting of principal component regression, non-linear principal component regression, partial least squares modeling and non-linear partial least squares modeling.