Improvement of Interfacial Adhesion Strength and Thermal Stability of Cu/p-SiC:H/SiOC:H Film Stack by Plasma Treatment on the Surface of Cu Film

A highly reliable interface of self-aligned barrier CuSiN thin layer between the Cu film and the nano-porous SiC:H (p-SiC:H) capping barrier (k=3.3) has been developed in the present work. With the introduction of self-aligned barrier (SAB) CuSiN between a Cu film and a p-SiC:H capping barrier, the interfacial thermal stability and the adhesion of the Cu/p-SiC:H film are considerably enhanced. A significant improvement of adhesion strength and thermal stability of Cu/p-SiC:H/SiOC:H film stack has been achieved by optimizing the pre-clean step before cap-layer deposition and by forming the CuSiN-like phase. This cap layer on the surface of the Cu can provide a more cohesive interface and effectively suppress Cu atom migration as well. Keyword: interfacial adhesion; thermal stability; self-aligned CuSiN process; diffusion barrier