Authors: A Colin P Morin F Cacho H Bono R Beneyton D Mathiot E Fogarassy
Publish Date: 2011/06/09
Volume: 104, Issue: 2, Pages: 517-527
Abstract
We present a study of the temperature nonhomogeneities induced by millisecond laser annealing in advanced CMOS technologies at die level Because of the design the device layout at the wafer surface introduces during this anneal significant spatial variations of optical absorption and heat transfer that can induce temperature nonuniformities over the die often called ‘pattern effects’ These temperature variations are becoming a major issue since they are the origin of significant device properties dispersion A complete optical and thermal simulation set has been developed to estimate the temperature variations induced by the topologies at the wafer surface during the laser anneal process The modelling has been validated by either a comparison with another software or reflectometry and electrical measurements on real structures This work demonstrates that the temperature variations are caused either by optical coupling or by thermal properties dispersion present at the wafer surface at the anneal step Finally we demonstrate that the impact of the thinfilm interferences and diffraction phenomena is the critical issue for these pattern effects
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