Improvement of interfacial adhesion strength and thermal stability of cu/cap barrier/low-k dielectric stack by plasma treatment on the surface of Cu film

A highly reliable interface of a self-aligned CuSiN thin layer between the Cu film and nano-porous SiC:H dielectric barrier (k = 3.8) has been developed in the present work. It is shown that when the self-aligned CuSiN barrier produced between a Cu film and a porous-SiC:H barrier, the interfacial thermal stability and the adhesion of the Cu/SiC:H film are considerable enhanced. Furthermore, this kind of multilayered structures such as CuSiN/SiC:H which can also achieve a low effective dielectric constant (k_eff.) with IMD film and possess excellent barrier properties. It is believed that the multi-layered barrier has a potential to satisfy the need of the 65 nm node and below. The mechanisms involved have been analyzed based on detailed characterization studies.