Patent ID: 7743783

Claim:
A method of recycling an acidic cobalt solution from a semiconductor process tool comprising the steps of: reclaiming used acidic cobalt solution from a drain of the semiconductor process tool wherein the used acidic cobalt solution flows from the drain and into a reclaim line; measuring conductivity of the used acidic cobalt solution with a conductivity probe connected to the reclaim line; sending a signal indicative of the conductivity to a controller and determining if the conductivity is within a predetermined conductivity range; recycling the used acidic cobalt solution to the semiconductor process tool if the conductivity is within the predetermined conductivity range and diverting at least a portion of the used acidic cobalt solution to a system drain if the conductivity is outside of the predetermined conductivity range wherein the step of recycling the used acidic cobalt solution comprises transferring the used acidic cobalt solution to a tank and pumping the acidic cobalt solution from the tank to an inlet of the semiconductor process tool; and adding fresh acidic cobalt solution to the tank when the level of the acidic cobalt solution in the tank reaches a low setpoint; wherein the step of adding fresh acidic cobalt solution to the tank comprises combining a first fluid with a second fluid to form the fresh acidic cobalt solution; and wherein the step of combining the first and second fluids comprises controlling the flow rate of the first fluid with a first flow controller and controlling the flow rate of the second fluid with a second flow controller.