Effect of plasma treatments on interface chemistry and adhesion strength between porous SiO2 low-k film and SiC/SiN layers

Abstract

In this study, the interface chemistry and adhesion strengths between porous SiO2, low-dielectric-constant film and SiN capping layer as well as SiC etch stop layer have been investigated under different plasma treatments. Elements of Si, O,and N constructed an interlayer region with mixing Si-N and Si-O bonds at the interface between the porous SiO2 film and SiN capping layer. After plasma treatments especially O-2 plasma, the oxygen content at the interface increased, and the binding energy obviously shifted to a higher level. Under nanoindentation and nanoscratch tests, interface delamination occurred, and the interface adhesion strength was accordingly measured. After plasma treatments especially the O-2 plasma, more Si-O bonds of high binding energy existed at the interface, and thus the interface adhesion strength was effectively improved. The adhesion energy Of SiO2/SiN and SiC/SiO2 interfaces was enhanced to 4.7 and 10.5 J/m(2) measured by nanoindentation test, and to 1.3 and 2.0 J/m(2) by nanoscratch test, respectively. (c) 2007 Elsevier B.V. All rights reserved.