Apparatus to monitor and add plating solution to plating baths and controlling quality of deposited metal

The present invention relates to plating baths or plating metal onto substrates. More particularly, she present invention relates to an apparatus and method for monitoring and adjusting conditions within plating baths and for plating metal onto substrates. An apparatus for monitoring and adding solution to a plating bath and controlling the quality of deposited metal. At least one monitor monitors at least one condition within a plating bath and produces at least one signal corresponding to the at least one condition. At least one controller receives the at least one signal produced by the at least one monitor, processes the at least one signal, determines whether an additional amount of at least one chemical should be added to the plating bath, and controls at least one valve for controlling flow of the additional amount of the at least one chemical. A pre-mix tank pre-mixes chemicals to be added to the tank. A plurality of holding tanks holds chemicals and supplies the chemicals to the pre-mix tank. At least one valve is arranged between each holding tank and the pre-mix tank. At least one valve is also arranged between the pre-mix tank and the plating bath.