Patent ID: 7542859
Filing Date: 2009-06-02
Classification: G01B,G01N

Abstract:
1. A method of creating a virtual profile library, the method comprising: obtaining a reference signal, wherein the reference signal was generated by measuring a signal off a reference structure on a semiconductor wafer with a metrology device; comparing the reference signal to a plurality of signals in a first library, and stopping the comparing when a first goodness of fit value is met; comparing the reference signal to a plurality of signals in a second library, and stopping the comparing when a second goodness of fit value is met; creating a virtual profile data space when the first and second goodness of fit values are not met, wherein the virtual profile data space is created using differences between a profile data space associated with the first library and a profile data space associated with the second library; creating a first virtual profile signal in the virtual profile data space; creating a virtual profile shape and/or virtual profile parameters based on the first virtual profile signal; and calculating a difference between the reference signal and the first virtual profile signal; comparing the difference to a virtual profile library creation criteria; and either storing in the virtual profile library the first virtual profile signal and the virtual profile data, which includes the virtual profile shape and/or virtual profile parameters, associated with the first virtual profile signal when the virtual profile library creation criteria is met, or applying a corrective action when the virtual profile library creation criteria is not met.