ELECTROLESS COPPER METALLIZATION 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/mm(2) failed to remove the copper from the TiN surface. It was found that the as-deposited copper layer (similar to 0.7 mu m) had a resistivity of similar to 2.0-2.3 mu Omega . cm, with a grain size of similar to 0.15 mu m. The topography of the Cu deposit was examined at bath temperatures of 70 and 55 degrees C using SEM and AFM. The mechanism of Cu plating at 70 degrees 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 degrees C the Cu deposit was more uniform due to the lower plating rate.