Superiority of DMAH to DMEAA for al CVD technology

Abstract

The superiority of dimethylaluminumhydride [(CH 3) 2AlH, DMAH] to dimethylethylaminealane [AlH 3N(CH 3) 2(C 2H 5), DMEAA] has been investigated from the view point of aluminum chemical vapor deposition (Al CVD) technology in ULSI manufacturing. Both DMAH and DMEAA have the same filling capability such as surface morphology and step coverage. For deposition reproducibility, the smaller activation energy is more suitable for manufacturing. The activation energy of Al deposition is found to be 0.38 [eV] for DMAH and 0.74 [eV] for DMEAA. These results mean the reproducibility of Al thickness using DMAH is superior to that using DMEAA. For safe storage and precise precursor delivery, the precursor should be chemically stable. From the results of measuring the pressure increase in vessel, it has shown that DMAH has superior chemical stability to DMEAA. Manufacturing apparatus such as Al CVD cluster module requires the deposition selectivity that is defined as Al deposition only on the desired areas of wafer surface and not on any parts of cluster module. Using DMAH, Al is deposited on barrier metal surface of silicon wafer, while Al is not deposited on the sealed anodic oxidized aluminum or the synthetic quartz. DMAH has shown excellent selectivity in comparison with DMEAA. Therefore, DMAH is superior to DMEAA as a precursor for the Al CVD technology in ULSI manufacturing.