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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 ϳ6 nm thick between the porous SiOCH film and SiCN layers was found to be composed of Si, N, C, and O. The SiOCH/SiCN interface was constructed by mixing bonds, including Si-C-N, Si-N-C, Si-O-C, Si-O 2 , etc. Under H 2 and NH 3 plasma treatments, a large amount of weak Si-CH 3 and SiO-CH 3 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/m 2 . After plasma treatments, especially NH 3 plasma, the adhesion strength was effectively improved to 2.13 J/m 2 .

In this study, an Si/PEOX/SiCN/SiOCH/SiCN multilayered film stack has been prepared by chemical vapor deposition. The bonding configurations between porous SiOCH film and SiCN etch stop layers have been analyzed by X-ray photoelectron spectroscopy, and the interface adhesion has been investigated by nanoindentation and nanoscratch tests. Elements of Si, C, N, and O constructed an interlayer region of about 10 nm with mixing bonds of Si to C, Si to N and Si to O at the interface between the porous SiOCH film and SiCN layers. During nanoindentation and nanoscratch tests, interface delamination occurred between SiOCH and SiCN layers due to the accumulation of sufficient shear stresses around the indented regions. The interface adhesion energy was accordingly measured as 1.68 J/m(2) by nanoindentation test with an applied load of 30 mN. With higher applied loads, the measured interface adhesion energy decreased. By the nanoscratch test, the interface adhesion energy was measured as about 0.91 J/m(2), lower than that obtained by nanoindentation test due to the mode mixity effect. (C) 2007 Elsevier B.V. All rights reserved

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