25 March 2010 Reflectivity metrics for optimization of anti-reflection coatings on wafers with topography
Author Affiliations +
Abstract
Anti-reflection coatings are commonly used in advanced photolithography in order to minimize CD variability caused by deviations in resist thickness and in the films and structures comprising the substrate. For a planar film stack, reflectivity calculations are a critical tool for optimization of parameters such as coating thicknesses and optical properties of anti-reflection coatings (TARCs and BARCs). However, with the exception of the first lithography layer, all layers on a production wafer have some degree of topography, so that reflectivity calculations for a planar film stack are not strictly correct. In this study, we evaluate three different reflectivity metrics that can be applied to wafers with topography: reflectivity for simplified planar film stacks, standing wave amplitude, and reflected diffraction efficiencies. Each of these metrics has a simple, physical meaning that will be described in detail in the presentation. We then evaluate how well these reflectivity metrics correlate with CD variability for two different example lithography steps: implant layers with STI (where a developable BARC might be used), and Litho-Etch-Litho-Etch style double patterning.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mark D. Smith, Mark D. Smith, Trey Graves, Trey Graves, John Biafore, John Biafore, Stewart Robertson, Stewart Robertson, } "Reflectivity metrics for optimization of anti-reflection coatings on wafers with topography", Proc. SPIE 7639, Advances in Resist Materials and Processing Technology XXVII, 763935 (25 March 2010); doi: 10.1117/12.846540; https://doi.org/10.1117/12.846540
PROCEEDINGS
11 PAGES


SHARE
Back to Top