Method and apparatus for estimating model parameters of and controlling a lithographic apparatus by measuring a substrate property and using a polynomial model

摘要

System and methods estimate model parameters of a lithographic apparatus and control lithographic processing by a lithographic apparatus. An exposure is performed using a lithographic apparatus across a wafer. A set of predetermined wafer measurement locations is obtained. Discrete orthonormal polynomials are generated using the predetermined substrate measurement locations. The overlay errors arising from the exposure are measured at the predetermined locations to obtain overlay measurements. The estimated model parameters of the lithographic apparatus are calculated from the overlay measurements by using the discrete orthogonal polynomials as a basis function to model the overlay across the wafer. Finally, the estimated model parameters are used to control the lithographic apparatus in order to provide corrected overlay across the wafer.

主权项

1. A method comprising:
performing a lithographic process using a lithographic apparatus across a substrate; using predetermined substrate measurement locations to generate discrete orthogonal polynomials; measuring a substrate property arising from the lithographic process at locations of the substrate corresponding to the predetermined measurement locations to obtain substrate property measurements; calculating estimated model parameters of the lithographic apparatus from the substrate property measurements by using the generated discrete orthogonal polynomials as a basis function to model the substrate property across the substrate; and controlling lithographic processing by the lithographic apparatus using the estimated model parameters.