2 May 2008 Measuring contact hole corner rounding uniformity using optical scatterometry
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Proceedings Volume 6792, 24th European Mask and Lithography Conference; 679212 (2008); doi: 10.1117/12.798790
Event: 24th European Mask and Lithography Conference, 2008, Dresden, Germany
Abstract
Uniformity distribution of the corner rounding radius of curvature is investigated using reflectance- and transmittance-based optical scatterometry. Arrays of square contact holes are measured at multiple locations on an ACI photomask using a broadband spectrophotometer capable of collecting polarized reflectance (Rs and Rp) and polarized transmittance (Ts and Tp) spectra in 190 - 1000 nm wavelength range in one-nanometer intervals. The measured spectra are analyzed using two-dimensional Rigorous Coupled-Wave Analysis algorithm (2D RCWA) in conjunction with the Forouhi-Bloomer dispersion relations for n and k. As a result of the analysis, the values of contact hole width and the radius of curvature associated with the corner rounding are determined at every measurement location. The measurements are presented as uniformity distribution maps and correlation plots, comparing the results with the values obtained using a conventional CD-SEM.
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John C. Lam, Alexander Gray, Stanley Chen, Jan Richter, "Measuring contact hole corner rounding uniformity using optical scatterometry", Proc. SPIE 6792, 24th European Mask and Lithography Conference, 679212 (2 May 2008); doi: 10.1117/12.798790; https://doi.org/10.1117/12.798790
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KEYWORDS
Reflectivity

Scatterometry

Transmittance

Photomasks

Spectrophotometry

Lamps

Light

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