Importance

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Abstract

Blending and pumping systems for accurately delivering desired amounts of processing fluids, particularly for use in semiconductor processing and semiconductor processors. Thee blending systems include one or more supply tanks from which a processing fluid is accurately pumped using the novel metering pump and associated pumping and blending methods. The blending systems preferably include a recycle line which includes a control valve which is controlled to recycle process fluid during an initial startup period. The outflow from the pump is preferably totally recycled during this startup period by blocking flow of process fluid to the blending container. The metering pump includes a pump housing having a pumping chamber which is partially defined by a displacement member, such as a flexible bellows structure. The pumping chamber is isolated from inlet and outlet via inlet and outlet valves, respectively. The inlet and outlet valves are positively controlled into open and closed positions using a control system which preferably includes an elctronic controller. The controller appropriately sequences the operation of the pump inlet and outlet valves relative to a displacement member actuator which drives the displacement member. The control is preferably accomplished by using electrically operated solenoid valves which control the flow of an intermediary control fluid, such as air or other suitable gas. The invention further includes methods of blending and pumping to provide accurate and low contamination of the process fluids being metered.

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First Claim