Effect of Post-Chemical-Mechanical Polishing Surface Treatments on the Interfacial Adhesion Energy between Cu and a Capping Layer

The effect of post-chemical-mechanical polishing (CMP) surface treatments on the interfacial adhesion energies between electroplated Cu thin film and SiNx capping layer was evaluated using a four-point bending test. The polished Cu surface was treated by one of three methods: no surface treatment, cleaning by plasma with a vacuum break, and cleaning by the wet chemical method. X-ray photoemission spectroscopy (XPS) analysis on the delaminated interfaces, cross-sectional high-resolution transmission electron microscopy (HR-TEM), and also the electron energy loss spectroscopy (EELS) analysis were performed on the interfaces. The interfacial adhesion energy increases with post-CMP cleaning, which is strongly influenced by the effective removal of residual oxygen at the Cu surfaces. (C) 2013 The Japan Society of Applied Physics