Electroless copper metallisation of titanium nitride

This paper reports on electroless copper plating as a novel low temperature, selective technique for metallisation of TiN. Various properties of the as-deposited copper were examined. The adhesion of the as-deposited Cu was tested by a quantitative pull test and a force of 1.5–1.7 kg/mm2 failed to remove the copper from the TiN surface. It was found that the as-deposited copper layer (∼ 0.7 μm) had a resistivity of ∼ 2.0–2.3 μΩ · cm, with a grain size of ∼ 0.15 μm. The topography of the Cu deposit was examined at bath temperatures of 70 and 55°C using SEM and AFM. The mechanism of Cu plating at 70°C was examined and it was postulated that the resulting non-uniform Cu layer was due to the fast rate at which the randomly scattered Pd seed nodules were being plated. At a bath temperature of 55°C the Cu deposit was more uniform due to the lower plating rate.