CAPABILITIES OF AN AMBIENT PRESSURE PLASMA FOR ACTIVATION IN LT WAFER BONDING PROCESSES

摘要

Standard cold plasma systems operate at low pressure. This paper presents the so-called nanoPREP ambient pressure plasma technology based on the dielectric barrier discharge (DBD) principle with optimized design for wafer bonding applications. The parameters of the system are introduced, the characteristics of the plasma discharge are shown dependent of these parameters. Plasma effects were analyzed on several material surfaces with different methods. Surface oxidation and hydrophilicity has been increased, the micro-roughness reduced. No additional metallic or particle contamination was added in the process. The bond energy of similar and as well of dissimilar material was highly increased after LT annealing, sufficient for further processing like splitting, back grinding or dicing. A cleaning effect of the plasma treatment can be stated because of the lack of the interface bubbles at Si-Si bonds.