Improvement of Al Filling Ability in Damascene Process

A novel Al chemical vapor deposition (CVD) technique called "CVD Al reflow trench fill" was developed using methylpyrrolidine alane (MPA) as a precursor in a damascene structure. The new method is based on the changes in deposition properties of CVD Al with the MPA precursor depending on its under layer. Using this characteristic, we completely filled a 40 nm-spacing trench and confirmed robust electrical properties. These results were again verified by comparing the bit line property of the Al damascene scheme with those of the Al reactive ion etch (RIE) scheme and low resistivity W (LRW) damascene structures.