| luminum nitride (AlN) has attracted much attention as a new electronic packaging substrate material because of its high thermal conductivity. In consequence of present research, a AlN sample with thermal conductivity higher than 200 W/mK was attained.;Research on selecting suitable organic additives for AlN tape casting slips based on four binders has been conducted in this study. Study in phase two was aimed at factors which affect the binder pyrolysis behavior and residual carbon formation. The third phase was focused on the fundamental effects of carbon residue on the sintering behavior and the thermal conductivity of AlN.;Organic additives for AlN casting slips were optimized. Four formulations based on different binders were developed. A new binder, polypropylene carbonate (PPC), with a clean burnout property was used for the first time for tape casting of AlN.;PPC binder was found to thermally decompose via a simple depolymerization mechanism. It was burned out more cleanly than PVB, a binder used widely in tape casting. Nevertheless, both binders left more carbon residue when they were burned out in the presence of AlN powder than when pyrolyzed alone. An interesting and unexpected conclusion from this study is that some plasticizers retard thermal decomposition of polymer binder through a chemical reaction.;The nature of the residual carbon on the AlN powder surface was examined with XPS and TEM. The surface of as-received AlN powder was covered by a thin layer of aluminum oxynitride and oxide mixture. A small portion of residual carbon from binder burnout was bound to oxygen atoms on the AlN powder surface, and the majority of the carbon was amorphous graphitoid carbon.;The surface C/O ratios were observed to correlate with the sintering behavior, the composition of the second phase, the second phase distribution, grain boundary composition, oxygen content in the AlN grain, and thermal conductivity of AlN samples. The C/O atomic ratio of 1.0 was found as a threshold. The AlN sample could not be sintered when the C/O ratio was higher than 1.0. In the region of C/O less than 1.0, a higher C/O ratio was beneficial to thermal conductivity. The carbon-deoxidation reaction reduced the solubility of... |
