Off-null focused beam scatterometry using spatially varying polarization states

Thesis (Ph. D.)--University of Rochester. The Institute of Optics, 2018.The microelectronics industry is driven by advancements which push feature sizes in devices to smaller and smaller scales. Optical scatterometry has filled a niche in the metrology of these devices which concentrates on speed, repeatability, and low cost. In this thesis, we present, to our knowledge, the first attempt at the use of spatially-varying input fields in optimizing the sensitivity of a single shot scatterometry measurement over many incident angles simultaneously. We present initial investigations of polarization generator designs using a single Spatial Light Modulator (SLM) and discuss the overall layout of the scatterometry system. We then present the calibration of the imaging polarimeter, which, along with a Thorlabs PAX5710IR2 polarimeter, is used to investigate calibration and feedback schemes for the SLM quantitatively. We present the initial simulations that guided the project and design of the system, along with our methods for the simulation of output irradiances for the output irradiance lookup tables to be used in parameter retrieval. Lastly, we present experimental results of parameter retrieval experiments using the simulated lookup table method, subsequent calibrations of the simulation using input and output polarimetry measurements, and the challenges associated. The International Technology Roadmap for Semiconductors claims that parameter retrieval can be performed through correlation with other methods which aren't feasible for rapid low cost manufacturing. We present our interpretation of this method and numerical results with a comparison of different input fields