In Situ Study of Stresses Generated During the Formation of Cobalt Disilicide and the Effect of Post Silicide Processing

Abstract

ABSTRACTSelf aligned cobalt disilicide technology is emerging as an excellent choice for gate and interconnection and contact metallization in VLSI. The presence of an as deposited, intrinsic stress in the cobalt film and the generation of stresses during its subsequent reaction with the underlying silicon and during post silicide processing can affect the mechanical stability and the performance of the overall device structure. This study involved the in situ observation of the stresses generated in thin films of cobalt (or silicide formed on reaction) on silicon as they react during a continuously ramped and cooled temperature cycle. The results will be presented, and in the light of a well characterized reaction sequence, possible governing mechanisms will be presented and discussed.