Method of forming nitride capped Cu lines with improved adhesion and reduced electromigration along the Cu/nitride interface

Abstract

The adhesion of a capping layer, e.g., silicon nitride, to inlaid Cu is improved with an attendant reduction in hillock formation and, hence, improvement in electromigration resistance, by laser thermal annealing the exposed surface of the inlaid Cu after CMP to remove copper oxide therefrom. Embodiments include laser thermal annealing in NH3 or H2 at a temperature of about 370° to about 420° for a short period of time, e.g., about 10 to about 100 nanoseconds, to remove the copper oxide. Embodiments also include sequentially and contiguously laser thermal annealing the exposed planarized surface of inlaid Cu, ramping up the introduction of SiH4 and then initiating (PECVD) of a silicon nitride capping layer. Embodiments also include Cu dual damascene structures formed in dielectric material having a dielectric constant (k) less than about 3.9.

Dependencies are inferred from the claim text.