Abstract
In this study, the interface chemistry and adhesion strength between a porous SiOCH extra-low-dielectric-constant film and SiCN etch stop layers were investigated with different plasma treatments. An interlayer of ∼6 nm thick between the porous SiOCH film and SiCN layers was found to be composed of Si, N, C, and O. The SiOCHSiCN interface was constructed by mixing bonds, including Si-C-N, Si-N-C, Si-O-C, Si- O2, etc. Under H2 and NH3 plasma treatments, a large amount of weak Si- CH3 and SiO- CH3 bonds were broken, and more Si-O related bonds of high binding energy formed at the interfaces. Moreover, under the accumulation of sufficient shear stresses around the indented regions during nanoindentation tests, interface delamination between the porous SiOCH film and SiCN layers occurred. The interface adhesion energy between untreated porous SiOCH film and SiCN layers was accordingly measured as 1.68 J m2. After plasma treatments, especially NH3 plasma, the adhesion strength was effectively improved to 2.13 J m2. © 2007 The Electrochemical Society.