Patent ID: 7761250

Claim:
A method of optimizing the design of an optical metrology system, the optical metrology system configured to measure a repeating structures on a workpiece and configured to meet two or more design goals, the repeating structure having profile parameters, the method comprising: developing an initial design for the optical metrology system based on a determined range of capabilities of the optical metrology system; setting two or more design goals for the optical metrology system to a corresponding value or range of values; developing a model for the optical metrology system using the initial design and the set two or more design goals for the optical metrology system; developing a prototype of the optical metrology system based on the initial design of the optical metrology system; collecting measured design goal data using the optical metrology system prototype and the model of the optical metrology system; if two or more measured design goals derived from the collected design goal data do not meet the set two or more design goals, modifying the initial design of the optical metrology system and iterating the developing the model of the optical metrology system, developing the prototype of the optical metrology system, collecting measured design goal data, performing a new comparison of new measured two or more design goals to the set two or more design goals, and modifying the initial design until there is a match of the new measured design goals to the set two or more design goals; using the designed optical metrology system, measuring a diffraction signal off the repeating structure; and extracting at least one profile parameter of the structure from the measured diffraction signal using profile extraction methods that include a regression method, a library method, a machine learning systems method or any combination of two or more thereof; wherein the workpiece is a wafer in a semiconductor application and wherein the optical metrology system comprises an optical metrology tool.