Fundamental evaluation of orientation and grain size of Cu film in Cu/TaWN/SiO₂/Si system

Abstract

Cu(111) preferential orientation is desired to improve the electromigration (EM) resistance in Si-large-scale integration (LSI) and 3D-LSI. In this study, we examine the orientation and grain size of a Cu film in a Cu/TaWN/SiO2/Si system by using a 5 nm-thick TaWN alloy film that functions as both a thin diffusion barrier and underlying material that induces preferential Cu(111) orientation. The Cu film with highly-oriented growth of Cu(111) and an average grain size of ~160 nm was obtained on the as-deposited TaWN(5 nm-thick)/SiO2/Si system. The Cu/TaWN/SiO2/Si system tolerates annealing at 700 °C for 60 min without any structural and/or configurational change.