Effect of plasma treatments on interface chemistry and adhesion strength between porous SiO 2 low- k film and SiC/SiN layers

Abstract

In this study, the interface chemistry and adhesion strengths between porous SiO 2 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 SiO 2 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 SiO 2/SiN and SiC/SiO 2 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.