Abstract: SVG/Thermco 7000 series VTRs (vertical thermal reactors) were purchased capable of running 100 production wafers in a single run. Manufacturing needs required an increase to 125 production wafers per run. Polysilicon deposition furnaces with five zone temperature control were capable of running 125 production wafers, but furnaces with three zone temperature control were not. The three zone temperature controlled furnace showed an elevated thickness signature near the top test wafer position. This increased thickness measured near upper specification limits. A designed experiment was run based on dummy wafer placement and end zone temperature setpoints. The optimized dummy wafer load and top and bottom temperature setpoints improved the wafer within-run uniformity from 8.0% to 1.8%. !0
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