Non-selective copper film growth on Kapton (polyimide) by MOCVD

Abstract High-purity polycrystalline Cu films have been deposited for the first time on a commercial polyimide using thermal, cold-wall, reduced-pressure (20 Torr) MOCVD. Two precursors were employed; Cu(acac) 2 and Cu(HFA) 2 . The deposition temperature ranged from 275 to 425 °C and the source temperature ranged from 85 to 150 °C depending on the source involved. The reaction proceeded with and without the help of H 2 O vapor. When H 2 O was used, the film growth rate was up to 420 A min −1 and grain sizes up to 1.5 μm were obtained in the case of the Cu(HFA) 2 source. H 2 O significantly increased the growth rate in the case of the Cu(aca) 2 source. When H 2 O was not used, with either sources, the grain size was smaller (0.7−1.1 μm) and the films were physically more optically reflective. In the first few minutes of the deposition, the deposited film consisted entirely of the copper oxide phase. As the reaction continued, pure Cu films were obtained. The films were characterized using XRD, LVSEM, SAXPS and RBS. Electrical resistivity of 3.25 μΩ cm was measured for films prepared with deposition temperatures of 420 °C and in the presence of H 2 O vapor. Simple Scotch-tape adhesion tests revealed qualitatively that the deposited films adhere well to the polyimide substrate.