Trench filling by ionized metal physical vapor deposition

Ionized metal physical vapor deposition (IMPVD) is a process in which sputtered metal atoms from a magnetron target are ionized by a secondary plasma, accelerated into the substrate, and deposited with moderately anisotropic fluxes. To investigate these processes, an integrated plasma equipment and feature scale model was developed to simulate the sputtering of metal atoms, their transport in IMPVD reactors, and their deposition into trenches. The model self-consistently predicts the magnitude and distributions (energy and angle) of the depositing metal flux and the profiles of metal deposits in trenches. The predicted profiles agree with experimentally observed trends. The results indicate that the ionization fraction of the depositing metal flux is the critical factor in trench filling. Formation of voids occurs when the ionization fraction of the depositing metal flux is too low or the aspect ratio of the trench is too large. As the aspect ratio of the trench increases, the ionization fraction required...