The Impact of Adsorbates on Metal Deposition through the Curvature Enhanced Accelerator Coverage Mechanism and Beyond

Abstract

Superconformal electrodeposition utilizing additives that adsorb on the deposit surface and either enhance or suppress metal deposition enabled the implementation of Cu damascene interconnects in microelectronics. The filling process is a consequence of the Curvature Enhanced Accelerator Coverage (CEAC) mechanism, which captures the interplay between adsorbate coverage and the metal deposition rate during area change that necessarily accompanies growth on nonplanar surfaces. CEAC-based models have successfully predicted superconformal deposition using a variety of different chemistries that yield void-free filling of fine features, as well as optically smooth, surfaces of metals such as Cu, Ag and Au. Herein a brief review of advances in the superconformal Au deposition will be detailed. Of particular interest are additives whose behavior is non-monotonic with adsorbate coverage that present new challenges for understanding as well as interesting opportunities for application.