US Patent 7743783 Method and apparatus for recycling process fluids

A method and apparatus for recycling a process fluid from a drain of a semiconductor process tool. The process fluid may be an acidic cobalt solution or an electroless cobalt solution used in a semiconductor process step to prevent electromigration in copper interconnects. The used process fluid is collected from the tool drain and recycled back to the tool inlet if a condition of the fluid is within a predetermined range. Otherwise, the used process fluid is drained from the system. The system may also operate in a bleed and feed mode where a portion of the used process fluid is periodically drained from the system.