Patent ID: 9645509
Date: 2017-05-09
CPC Classifications: G03F

Claim:
1. A method for simulating aspects of a lithographic process, comprising: securing data regarding characteristics of a lithographic apparatus; providing non-secure data about the lithographic process, wherein the non-secure data are not hidden; generating mathematical models representing the secured data and the non-secure data, wherein the secure data are encapsulated using a transformation function; and providing the mathematical models to a simulation process while keeping the secured data hidden to the simulation process, thereby allowing the simulation process to be performed using the mathematical models and without the simulation process having access to the secured data which is kept hidden from the simulation process by having been encapsulated using the transformation function into the mathematical models, wherein the transformation function includes computing one or more transmission cross coefficients (TCCs) comprising a plurality of eigen-systems representing the lithographic apparatus, and wherein the simulation process uses the mathematical models to form a simulated image corresponding to an actual image of the lithographic process, the actual image being an image as if produced by projecting a portion of a mask layout onto a substrate using the lithographic apparatus.