Importance

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Abstract

A method for the fluid treatment of semiconductor wafers includes a treatment vessel having opposed first and second ports, and means for holding wafers in a flow path therebetween. A flow segment comprising in sequence, a first vent, a first valve, an inlet, a second valve and a second vent extends between the first and the second port so as to constitute, together with the vessel, a closed fluid loop. Preferably, the first and second ports are top and bottom ports, with a flow path extending vertically therebetween. The loop is maintained hydraulically full, whereby filling the vessel with a treatment fluid at the inlet, flushes a preceding treatment fluid from the system. A sequence of treatment fluids of differing densities may be provided at the inlet, and a vent and a valve are controlled to fill the loop from the bottom, in the event the treatment fluid is denser than the preceding fluid, or from the top, in the event the fluid is lighter than the preceding fluid. A circulation pump recirculates fluid within the loop. In another aspect, a fluid delivery system for the delivery of a sequence of high purity treatment fluids to a treatment vessel includes a measuring tank having opposed ports and configured for plug flow between the ports, and a metering pump having its inlet connected to a said port for withdrawing metered amounts of fluid from the tank. A plurality of reservoirs of treatment fluid are each connected via a respective associated valve to one of the said ports. The tank is maintained hydraulically full, so that actuating the pump to withdraw a metered volume of fluid from the tank, and opening a valve associated with a selected treatment fluid draws the metered volume of the selected treatment fluid into the tank. Passive or non-mechanical means is provided for delivering the contents of the tank to a treatment vessel. In a preferred embodiment, the opposed tank ports are top and bottom ports, and the treatment fluids are fluids of differing densities, with the fluids of lesser density each connected via an associated valve to the top port, and the fluids of greater density each connected via an associated valve to the bottom port, minimizing convective mixing during metered filling. A mixing tank may be provided, between the measuring tank and the treatment vessel. Mixing may be accomplished by bubbling a gas through the fluid held in the mixing tank. Methods according to the invention for cleaning semiconductor wafers are disclosed.

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First Claim