Patent ID: 9378309
Filing Date: 2016-06-28
CPC Classification: G02B,G03F,G06F

Claim Text:
1. A method comprising: obtaining, by a computer system comprising hardware, model coefficients representing optical behavior of a lithographic process; obtaining, by the computer system, model coefficients representing optical behavior of a reference lithographic process separate from the lithographic process to which the lithographic process is to be tuned, wherein tuning comprises substantially matching the optical behavior of the lithographic process to the reference lithographic process, wherein the obtained model coefficients for the lithographic process and the reference lithographic process both comprise a non-diagonalized matrix of elements; and tuning, by the computer system, the lithographic process to the reference lithographic process by determining values of a plurality of design variables representing adjustable characteristics of the lithographic process that cause a termination condition corresponding to a difference between the obtained model coefficients for the lithographic process and the reference lithographic process to be reached, the lithographic process being configured for imaging a portion of a design layout onto a substrate using a lithographic projection apparatus comprising an illumination source and projection optics.