Characterization of film uniformity in LPCVD TEOS vertical furnace

Wafer uniformity of silicon oxide deposited on 8-in wafer using LPCVD TEOS vertical furnace is examined with an attempt to understand a source of poor uniformity in the bottom zone as observed in most TEOS batch process. By utilizing boat rotation capability, more information can be obtained regarding a possible flow dynamics of the reactive gases, the mechanism that might be responsible for thickness distribution within wafer. Importantly, the results from this study suggested that the nonuniformity of the oxide film deposited using TEOS is most influence by the kinetics of the decomposition reaction of TEOS rather than a temperature variation on the substrate surface.