Formation of High Quality Pure Aluminum Films by Low Kinetic Energy Particle Bombardment

Abstract

Low kinetic energy particle process in which the surface of the sputter‐deposited thin film is concurrently bombarded with low energy ions during the entire period of film growth has been established by employing a newly developed RF‐dc coupled mode bias sputtering technology. Applying this process to pure aluminum metallization, various improvements in the properties of aluminum thin films have been achieved, i.e., the crystallinity enhancement as well as excellent surface smoothness has been realized. Furthermore, hillock‐free aluminum thin films have been also obtained by this process, which is of paramount importance in realizing reliable multilevel interconnection scheme for ultralarge scale integrated circuits.