10 April 2015 Silicon fin line edge roughness determination and sensitivity analysis by Mueller matrix spectroscopic ellipsometry based scatterometry
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Abstract
Measurement and control of line edge roughness (LER) is one of the most challenging issues facing patterning technology. As the critical dimensions (CD) of patterned structures decrease, LER of only a few nanometers can negatively impact device performance. Here, Mueller matrix spectroscopic ellipsometry (MMSE) based scatterometry is used to determine LER in periodic line-space structures in 28 nm pitch Si fin samples fabricated by directed selfassembly (DSA) patterning. The optical response of the Mueller matrix (MM) elements is influenced by structural parameters like pitch, CD, height, and side-wall angle (SWA), as well as the optical properties of the materials. Evaluation and decoupling MM element response to LER from other structural parameters requires sensitivity analysis using simulations of optical models that include LER. Here, an approach is developed that quantifies Si fin LER by comparing the optical responses generated by systematically varying the grating shape and measurement conditions. Finally, the validity of this approach is established by comparing the results obtained from top down scanning electron microscope (SEM) images and cross-sectional TEM image of the 28 nm pitch Si fins.
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Dhairya Dixit, Dhairya Dixit, Samuel O'Mullane, Samuel O'Mullane, Sravan Sunkoju, Sravan Sunkoju, Erik R. Hosler, Erik R. Hosler, Vimal Kamineni, Vimal Kamineni, Moshe Preil, Moshe Preil, Nick Keller, Nick Keller, Joseph Race, Joseph Race, Gangadhara Raja Muthinti, Gangadhara Raja Muthinti, Alain C. Diebold, Alain C. Diebold, } "Silicon fin line edge roughness determination and sensitivity analysis by Mueller matrix spectroscopic ellipsometry based scatterometry", Proc. SPIE 9424, Metrology, Inspection, and Process Control for Microlithography XXIX, 94242P (10 April 2015); doi: 10.1117/12.2185543; https://doi.org/10.1117/12.2185543
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