Contact Fill by Ionized Cluster Beam

Publisher Website
Google Scholar
Abstract
Ionized cluster beam (ICB) deposition of TiN barrier metal for ultra large scale integration (ULSI) applications has been developed. The bottom coverage of reactive-ICB was 54% and 24% for 4.0 and 6.7 aspect ratio contacts (2.0 µm in depth and 0.5 µm amd 0.3 µm in diameter). Therefore the ICB has high potential to fill sub-half-micron contact holes with high aspect ratios. The resistivity of Ti and TiN deposited by ICB and reactive-ICB is found to be 50 µQ cm and 180 µQ cm, respectively, at a substrate temperature of 300°C. The ICB can also provide low contact resistance and good adhesion by low energy ion bombardment during film growth. The beam simulation explains the bottom coverage of ICB as well as conventional sputtering. Using the larger number of atoms in a cluster, the bottom coverage becomes almost 100% due to the long mean free path of the deposited cluster in gas and its heavy mass.