Abstract
In this study, the interface chemistry and adhesion strengths between Cu and SiCN etch stop layers have been investigated under different plasma treatments. From the examination of interface microstructures and the analyses of chemical compositions and bonding configurations, an oxide layer was found to exist at the untreated CuSiCN interface. After H2 and N H3 treatments, the amount of oxides was effectively reduced. Some Cu silicides formed during SiCN deposition, and Cu nitrides even formed under N H3 plasma treatment. The adhesion strengths of the CuSiCN interfaces were measured by nanoindentation and nanoscratch tests under which interface delamination occurred around indented regions. The adhesion energy of the untreated CuSiCN interface was obtained as about 4.98 and 0.98 J m2, respectively, by nanoindentation and nanoscratch tests. After H2 and N H3 plasma treatments, the adhesion energy was effectively improved to 5.90 and 5.99 J m2 by nanoindentation test, and to 1.74 and 2.58 J m2 by nanoscratch test, respectively, because of the removing of oxides and the formation of Cu silicides and nitrides at the CuSiCN interfaces. © 2007 The Electrochemical Society.