US Patent 8214771 Scatterometry metrology target design optimization

A metrology target design may be optimized using inputs including metrology target design information, substrate information, process information, and metrology system information. Acquisition of a metrology signal with a metrology system may be modeled using the inputs to generate one or more optical characteristics of the metrology target. A metrology algorithm may be applied to the characteristics to determine a predicted accuracy and precision of measurements of the metrology target made by the metrology system. Part of the information relating to the metrology target design may be modified and the signal modeling and metrology algorithm may be repeated to optimize the accuracy and precision of the one or more measurements. The metrology target design may be displayed or stored after the accuracy and precision are optimized.