US Patent 7241342 Non-dripping nozzle apparatus

According to one aspect of the invention, a dispense head for a wafer processing apparatus is provided. The dispense head may include an inlet, at least one outlet, a drain, and a passageway therethrough interconnecting the inlet, the outlet, and the drain. The inlet may be at a first height above a bottom of the passageway, the outlet may be at a second height above the bottom, and the drain may be at a third height above the bottom. A first valve may be connected to the inlet, and a second valve may be connected to the drain. When the first valve is opened and the second valve is closed, fluid flows into the inlet and out of the outlet. When the second valve is opened and the first valve is closed, fluid from the passageway flows out of the drain. A pump may be connected to the drain.