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

Ever since Al(Cu) wires were replaced by Cu to reduce RC delay, the development of lower k dielectric materials has been a challenge to the back end of line (BEOL) process [1,2]. Copper wiring with low-k or ultra low-k (ULK) dielectrics for high-performance CMOS IC’s requires the use of a robust dielectric cap barrier to prevent inter- and intra-level Cu diffusion and also to maintain device yield and reliability. Plasma Enhanced Chemical Vapor Deposited (PECVD) low-k SiCNH and SiN are the predominant dielectric Cu diffusion caps used by the industry, in part due to the strong cap/Cu debond energies [3]. This paper will present the ultrathin (