Finite Element Simulations of the Mechanical Stress in and Around Narrow Tisl2Lines

Abstract

AbstractThe primary objective of this work is to carry out a combined experimental and numerical investigation of the mechanical stress induced during the Ti-silicidation of narrow lines spaced by a Poly Buffered Local field oxide. Therefore micro-Raman spectroscopy (μRS) measurements of local mechanical stress are combined with simulations by Finite Element Modeling (FEM). Numerical determination of the local stress in the Si-substrate by means of FEM becomes more and more important when scaling down the device dimensions because the spatial resolution of μRS is limited at about 1μm and because the stress in the Si-substrate underneath silicided lines can not be detected using pRS unless the silicide is very thin. The Finite Element analysis was done using SYSTUS and involves a two dimensional plane strain thermo-elastic formulation. A good agreement was obtained between the FEM simulations and the μRS data for line widths above 1Bm making the extrapolation of the FEM to line widths smaller than I1m an attractive alternative for μRS.