INFLUENCE OF LINE DIMENSIONS ON THE RESISTANCE OF CU INTERCONNECTIONS

As dimensions reach the deep-submicrometer level on the order of the m ean-free path of electrons, increases in the resistivity of a metal co rresponding to reductions of wire dimensions is a concern. To understa nd the resistance dependence on the dimensions, resistance of Cu versu s interconnection size was analyzed. The experimental values were in g ood agreement with Fuchs' size-effect theory. The resistance of Cu inc reased nonlinearly as line width decreased. This enhancement was attri buted to the increased surface and grain boundary scattering. Almost 5 0% of the electrons elastically scatter during transport in wires with widths below 0.5 mu m. It will be important in the future to develop interconnections with smooth surfaces on all sides to maximize elastic scattering of electrons.