Mechanical behaviour of submicron multilayers submitted to microtensile experiments

The mechanical strength of layers used in microelectronic circuits is not well understood. In this study in situ microtensile tests were performed in a scanning electron microscope on various multilayers of Al-0.5%Cu, Ti and TiN deposited on a Ti substrate. Film fracture occurred in two distinct modes, either perpendicular to the loading or at a 45 degrees angle to the loading direction. Samples were loaded until the cracked films began to debond from the substrate. By using X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) the weak interface was determined to be the Al to Ti interface. The strength of this interface was calculated to be 0.5 J/m(2), which is in good agreement with theoretical predictions. (C) 1999 Elsevier Science S.A. All rights reserved.