Process and apparatus for depositing aluminum oxide

PROBLEM TO BE SOLVED: To provide a process and apparatus for Al 2 O 3 CVD on silicon wafers using aluminum tri-isopropoxide(ATI) in a high-volume production environment. SOLUTION: The conditions required to use ATI in a production environment and to provide maximum utilization of ATI are delivery of ATI via direct evaporation. The ATI source bottle is pumped out (bypassing substrates 10) until signals of propene and isopropanol by IR spectroscopy or mass analysis are reduced to below 1% of process pressure before start of aluminum oxide deposition and pure ATI is supplied. Further heating of tetramer of raw material supplied before operation at 120°C for 2 hours assures complete conversion to trimer. The ATI is stored at 90°C to minimize decomposition during idle periods and heating at 120°C for 2 hours allows recovery of the trimer. The ATI is held at 120°C to minimize decomposition during periods of demand. COPYRIGHT: (C)1996,JPO