ABSTRACT
Physical vapor deposition (PVD) thin film technology covers a rather broad range of deposition techniques. The general feature that describes PVD is that films are deposited atomically by means of fluxes of individual neutral or ionic species. The primary semiconductor applications for PVD technology are the deposition of metal and compound lines, pads, vias, contacts, and related connections which are used to connect with the junctions and devices present on the Si wafer surface. The goal of a thermal reflow process is that atoms move from the planar or field areas of the sample towards inset or deep features, such as trenches or vias. A variation on reflow technology that has been developed recently is known generically as 'high pressure filling'. Thermal reflow processes require high levels of cleanliness because surface contamination of the wafer or gas phase impurities such as oxygen or water may significantly impede the surface diffusion process.
