Abstract: Methods and systems for performing spectroscopic reflectometry based measurements of deep, large pitch semiconductor structures at high throughput are presented herein. A multi-step regression algorithm employs a non-periodic electromagnetic (EM) solver, i.e., an EM solver that does not rely on a Fourier based analysis. The multi-step regression algorithm utilizes both incoherent and coherent reflections resulting in faster and more accurate estimates of parameters of interest, including the depth of deep trench or deep hole structures. The coherent sum of reflection coefficients captures height differences among sub-structures of a structure under measurement, whereas an incoherent sum of reflection coefficients largely ignores the height differences.

Abstract: Methods and systems for performing spectroscopic measurements of asymmetric features of semiconductor structures are presented herein. In one aspect, measurements are performed at two or more azimuth angles to ensure sensitivity to an arbitrarily oriented asymmetric feature. Spectra associated with one or more off-diagonal Mueller matrix elements sensitive to asymmetry are integrated over wavelength to determine one or more spectral response metrics. In some embodiments, the integration is performed over one or more wavelength sub-regions selected to increase signal to noise ratio. Values of parameters characterizing an asymmetric feature are determined based on the spectral response metrics and critical dimension parameters measured by traditional spectral matching based techniques.

Abstract: Methods and systems for performing spectroscopic measurements of asymmetric features of semiconductor structures are presented herein. In one aspect, measurements are performed at two or more azimuth angles to ensure sensitivity to an arbitrarily oriented asymmetric feature. Spectra associated with one or more off-diagonal Mueller matrix elements sensitive to asymmetry are integrated over wavelength to determine one or more spectral response metrics. In some embodiments, the integration is performed over one or more wavelength sub-regions selected to increase signal to noise ratio. Values of parameters characterizing an asymmetric feature are determined based on the spectral response metrics and critical dimension parameters measured by traditional spectral matching based techniques.