A system and method is disclosed for adjusting the ratio of deposition
times to optimize via density and via fill in an aluminum multilayer
metallization process during a manufacturing process of a semiconductor
wafer. In a two-step cold/hot aluminum sputtering process via fill
becomes more challenging as via density increases. The invention
increases the percentage of successful via fills by changing the ratio of
the cold/hot deposition times. Denser via structures require extended
cold deposition times to compensate for higher via density. The
percentage of successful via fills was increased from forty percent (40%)
to seventy percent (70%) by changing the ratio of the cold/hot deposition
times from 60:40 to 79:21.