Fabrication of Uniform Sized Metal Spheres by Plasma Induced Dewetting

Sn and InSn metal spheres were fabricated by plasma induced dewetting with various conditions. Dewetting was effective under a hydrogen plasma environment despite the absence of an external heat source. FE-SEM images revealed that hydrogen plasma dewetting of Sn and InSn films proceeded through heterogeneous hole nucleation on the film surface and films changed to spherical with no large aggregation while there were large aggregations under thermal dewetting. Droplet size was controllable by selecting the plasma treatment conditions and initial film thickness. The longer films were plasma-treated, sphere size was decreased and larger spheres were divided to smaller ones. In addition, increasing plasma power yielded increasing sphere size regularity. It was suggested that plasma induced the digestive ripening of the metal spheres which interpreted by charge effect in colloid system.