Second Generation Copper Dielectric Barrier (BLOk II): k Reduction and Interface Control To Improve TDDB and EM

Abstract

Sub-45nm backend device integration requires material improvements for further RC reduction. One of the key candidates to achieve lower RC is the dielectric barrier. The dielectric constant of the copper barrier can be reduced to <4.0 by additional carbon doping. In addition, this new material can still maintain comparable copper barrier properties and etch selectivity to the current 45nm dielectric barrier baseline. To meet the challenges of the device shrink, advanced interface management is required to achieve good TDDB and EM. An Enhanced Nitride Interface (ENI) concept was adopted to maximize the interfacial mechanical and electrical strength without negative impacts on copper electrical performance.