Texture evolutions of ionized metal plasma Cu seed layers on tantalum nitride barriers

Ionized metal plasma (IMP) was a favorable method for the deposition of thin barrier and seed layers due to its sufficient bottom coverage in high aspect ratio features. In this study, the texture evolution of IMP copper (Cu) seed layers on IMP tantalum nitride barriers deposited by various nitrogen flow rates were investigated. The (111)/(200) ratio of the Cu seeds was found to relate to the grain size of the tantalum nitride substrates. A proposed model revealed that the surface energy reduction of the Cu deposition was a main factor to determine the (111)/(200) ratio of the Cu seeds.