Method for tuning barrel reactor purge system

摘要

A method for tuning a purge system of a barrel reactor (10) used for chemical vapor deposition of layers of material on semiconductor wafers (W) includes placement of rotameters (42A, 42B, 42C, 42D) and adjustable flow-control valves (44A, 44B, 44C, 44D) in each of multiple purge lines (34, 36, 38, 40). The flow rates of purge gas in the lines (34, 36, 38, 40) are monitored and the valves (44A, 44B, 44C, 44D) adjusted to make sure that the flow is all in a direction toward the barrel reactor (10), so that there is no siphon effect to draw reactant gases into the purge system. The oxygen presence in the barrel reactor (10) is also monitored and the flow rates adjusted to reduce the oxygen presence. The flow rates are adjusted to assure full purge of reactant gases from the barrel reactor (10) after a chemical vapor deposition cycle is complete. Reduced levels of metals contamination in layers of deposited material are achieved.