Ultrathin (8-14 nm) conformal SiN for sub-20 nm Copper/Low-k Interconnects

Abstract

A multilayer SiN barrier film with high breakdown field and low leakage current is developed for Cu low-k interconnects and is compared with the SiCNH barrier film used in previous technology nodes. Ultrathin SiN barrier cap films also provide high conformality and fill recessions in Cu lines as observed after CMP. The conformal ultrathin (8-14 nm) multilayer SiN cap is robust with higher breakdown field, lower leakage and forms a good oxidation barrier. The electromigration activation energy for a SiN cap layer of 10-12 nm dielectric thickness is about 0.9 eV.