Sn microparticles made by plasma-induced dewetting

Abstract

Micrometer-scale Sn particles are produced by plasma treating Sn films from 50nm to 2000nm on silicon oxide substrates. Plasma treatment is conducted using an inductively coupled plasma source. Behaviors of spinodal dewetting as well as hole nucleation and growth are observed when analyzing the average particle size with its initial film thickness and monitoring the morphological evolution of the dewetting film. A range of RF powers are evaluated to observe changes in particle size and size distribution. When increasing the RF power of the plasma treatment, the particle size and size distribution decreases, while the number of particles per area increases. With the help of the dewetting results on smooth substrates, an attempt is made to produce an array of Sn particles using a templated substrate to imitate the Sn solder bumps used in semiconductor packaging.