Scatterometry metrology target design optimization

An apparatus for optimizing a metrology target design, comprising:

• a) an optical simulator configured to receive inputs including information relating to the metrology target design, information relating to a substrate on which a metrology target is to be formed, information relating to a process used to form the metrology target, or information relating to a metrology system to be used to measure the metrology target, wherein the optical simulator is further configured to model acquisition of a metrology signal with the metrology system using the inputs to generate one or more optical characteristics of the metrology target;
• b) a metrology simulator configured to apply a metrology algorithm to the optical characteristics to determine a predicted accuracy or precision of measurements made with the metrology system using the metrology target on the substrate;
• and
• c) an optimization loop configured to modify at least a portion of the information relating to the metrology target design to optimize the design to produce an optimized metrology target design, wherein the optimization loop optimizes the predicted accuracy and precision of the one or more measurements by repeatedly i) models acquisition of a metrology signal by the metrology system using the inputs to generate one or more optical characteristics of the metrology target, ii) applies a metrology algorithm to the one or more optical characteristics to determine a predicted accuracy and precision of one or more measurements made with the metrology system using the metrology target on the substrate, and iii) modifies at least a portion of the information relating to the metrology target design.

An apparatus for optimizing a metrology target design comprising:

• a processor;
• a memory;
• instructions embodied in the memory for execution by the processor, the instructions being configured to optimize a metrology target upon execution by the processor, the instructions comprising:
• a) instructions for receiving inputs including information relating to the metrology target design, information relating to a substrate on which the metrology target is to be formed, information relating to a process used to form the metrology target, and information relating to a metrology system to be used to measure the metrology target;
• b) instructions for modeling acquisition of a metrology signal with the metrology system using the inputs to generate one or more optical characteristics of the metrology target;
• c) instructions for applying a metrology algorithm to the one or more optical characteristics to determine a predicted accuracy and precision of one or more measurements made with the metrology system using the metrology target on the substrate;
• d) instructions for modifying at least a portion of the information relating to the metrology target design;
• d′) instructions for repeating the instructions for modeling acquisition of a metrology signal with the metrology system, applying a metrology algorithm to the one or more optical characteristics, and modifying at least a portion of the information relating to the metrology target design to optimize the accuracy and precision of the one or more measurements;
• and
• e) instructions for displaying or storing information representing the metrology target relating to the metrology target design after the accuracy and precision are optimized.

A non-transitory computer readable medium having computer readable instructions embodied therein, the instructions being configured to implement a method for optimizing a metrology target upon execution by the processor, the method comprising:

• a) receiving inputs including information relating to the metrology target design, information relating to a substrate on which the metrology target is to be formed, information relating to a process used to form the metrology target, and information relating to a metrology system to be used to measure the metrology target;
• b) modeling acquisition of a metrology signal with the metrology system using the inputs to generate one or more optical characteristics of the metrology target;
• c) applying a metrology algorithm to the one or more optical characteristics to determine a predicted accuracy and precision of one or more measurements made with the metrology system using the metrology target on the substrate;
• d) modifying at least a portion of the information relating to the metrology target design;
• d′) repeating modeling acquisition of a metrology signal, applying a metrology algorithm to the one or more optical characteristics and modifying at least a portion of the information relating to the metrology target design to optimize the accuracy and precision of the one or more measurements;
• and
• e) displaying or storing information representing the metrology target design after the accuracy and precision are optimized.