Metrology of optically-unresolved features using interferometric surface profiling and RCWA modeling

Peter De Groot, Xavier Colonna de Lega, Jan Liesener, Michael Darwin
2008 Optics Express  
Rigorous coupled wave analysis (RCWA) interprets 3D whitelight interference microscopy profiles and reveals the dimensions of optically-unresolved surface features. Measurements of silicon etch depth of a 450-nm pitch grating structure correlate to atomic force microscopy with R 2 = 0.995 and a repeatability of 0.11nm. This same technique achieves a <1nm sensitivity to 80-nm lateral widths of 190-nm pitch gratings using a 570-nm mean wavelength.
doi:10.1364/oe.16.003970 pmid:18542494 fatcat:3lodgequvnbvrgkrrrjjwc4qze