A novel interlevel contact via structure having low contact resistance and
improved reliability, and method of forming the contact via. The method
comprises steps of: etching an opening through an interlevel dielectric
layer to expose an underlying metal (Copper) layer surface; and,
performing a low energy ion implant of an inert gas (Nitrogen) into the
exposed metal underneath; and, depositing a refractory liner into the
walls and bottom via structure which will have a lower contact resistance
due to the presence of the proceeding inert gas implantation. Preferably,
the inert Nitrogen gas reacts with the underlying exposed Copper metal to
form a thin layer of CuN.