ION-ASSISTED SELECTIVE DEPOSITION OF ALUMINUM FOR VIA-HOLE INTERCONNECTIONS

Recently we have demonstrated the existence of the so-called sputter yield amplification effect, based on the preferential sputtering of a particular species during the ion bombardment of composite solids. This work presents a more elaborate study of the sputter yield amplification effect using the dynamic Trim version T-DYN. General rules are given as to when the amplification effect is most pronounced and when it is suppressed, as well as its dependence on various parameters. The potential applications of the amplification effect are also discussed. In particular, the use of the effect as a planarization technique during ion-assisted deposition of Al is studied both theoretically and experimentally. It is shown that under low-energy argon ion bombardment Al can be selectively deposited onto Al surfaces while at the same time its growth on W covered SiO2 surfaces is totally prohibited.