| 主权项 |
1. A computer-implemented method for generating an optical model of a structure to be measured on a semiconductor wafer, comprising:
selecting nominal values and one or more different values of process parameters for one or more process steps used to form the structure on the wafer, wherein the one or more process steps comprise lithography; simulating one or more characteristics of the structure that would be formed on the wafer using the nominal values; generating an initial model of the structure based on results of said simulating; simulating the one or more characteristics of the structure that would be formed on the wafer using the one or more different values as input to the initial model; translating results of both of the simulating steps into the optical model of the structure; and determining parameterization of the optical model based on how the one or more characteristics of the structure vary between at least two of the nominal values and the one or more different values, wherein the selecting step, both simulating steps, the generating step, the translating step, and the determining step are performed without using images of the structure as formed on a wafer and before the structure is formed on any wafers, and wherein the selecting step, both simulating steps, the generating step, the translating step, and the determining step are performed using a computer system. |
