- Develop RCWA-based OCD modeling methodologies for diffractive nanostructures.- Identify critical degrees of freedom (DOF) and fitting parameters required for optimize diffractive element process maps - Explore and propose techniques to enhance the accuracy of model fitting compared against ground truth experimental data- Assess the Gauge Repeatability and Reproducibility (GR&R) of OCD equipment.- Integrate RCWA findings and improve models for supporting design validation simulations and process control recommendations