Selective local metal cap layer formation for improved electromigration behavior

摘要

A method of forming a wiring structure for an integrated circuit device includes forming a first metal line within an interlevel dielectric (ILD) layer, and forming a second metal line in the ILD layer adjacent the first metal line; masking selected regions of the first and second metal lines; selectively plating metal cap regions over exposed regions of the first and second metal lines at periodic intervals such that a spacing between adjacent metal cap regions of an individual metal line corresponds to a critical length, L, at which a back stress gradient balances an electromigration force in the individual metal line, so as to suppress mass transport of electrons; and wherein the metal cap regions of the first metal line are formed at staggered locations with respect to the metal cap regions of the second metal line, along a common longitudinal axis.