PVD THERMAL EVAPORATION
PVD thermal evaporation utilizes heat to form a coating over a substrate. A thin sheet of metal is heated until it has reached its vaporization point. Upon it being melted, it then covers the wafer to form the film. However, because this method involves evaporated materials, physics play a role in directing the evaporated metal towards the heat source. This can then create a lack of coverage on the substrate itself.
Sputtering solved thermal evaporation’s poor coverage areas. By deploying thin film metals via “injection” the metals need not worry about the atoms directing themselves in a set direction. Essentially, the atoms of the metal are “knocked-off” the base and onto the wafer. Sputtering has become one of the most widely used techniques in PVD nowadays and is now the preferred method over thermal thin film evaporation