Sn metal spheres were produced by treatment of Sn films in various atmospheres. Sn films of different thicknesses (100-1000 nm) were used, and the heat-treatment was carried out either in a vacuum, in a hydrogen plasma, or in an Ar plasma. The as-deposited Sn films were dewetted as a result of a morphology change from a film to metal particles during post-treatment The metal particles produced by heat-treatment in a hydrogen plasma were more spherical than those produced using an Ar plasma or without any plasma. As a result of spinodal dewetting, the mean diameter of the particles was closely related to the thickness of the Sn film. (C) 2011 Elsevier B.V. All rights reserved.