Electroless Deposition of NiMoB Diffusion Barrier Layer Film for ULSI-Cu Metallization

摘要

NiMoB alloy films were deposited on silicon substrate by electroless deposition for diffusion barrier application in copper interconnects technology, NiMoB(40nm)/SiO_2/Si and NiMoB(20nm)/Cu(40nm)/NiMoB(40nm)/SiO_2/Si samples were prepared and annealed ai temperatures ranging from 400°C to 600°C. Samples were characterized by X-ray diffraction(XRD),.X-ray photoelectron spectroscopy(XPS), Four Point Probes(FPP) and Atomic Force Microscopy(AFM) to investigate the phases, composition, sheet resistance and surface morphology. The results showed that electroless deposited NiMoB film can be used as an effective Cu diffusiori barrier layer until 500°C. And the failure mechanism is that NiMoB crystallized and grains grew after annealing at high temperature, a large number of Cu grains passed through NiMoB film via grair boundaries and then reacted with Si substrate and oxygen, causing the generation of highly resistive Cu_4Si and CuO.