Patent ID: 7717060

Claim:
An electroless plating apparatus, comprising: a wafer processing chamber, the wafer processing chamber containing a bath solution in which a semiconductor device is immersed; a plating container comprising a plating bath for holding a reducing agent for electroless plating of a metal onto the semiconductor device, the plating container being coupled to the wafer processing chamber; a first valve having an input coupled to the plating bath, and an output; an analysis module coupled to the output of the first valve, the analysis module determining a concentration of the reducing agent of a sample of the plating bath by increasing a pH of the sample and measuring a quantity of hydrogen evolved from the sample wherein the analysis module indicates that more reducing agent is needed when the concentration of the reducing agent is below a predetermined level; a replenishment module having an output for supplying reducing agent to the plating container; and a second valve having an input coupled to the output of the replenishment module, an output coupled to the plating bath for providing reducing agent to the plating bath, and a control input coupled to the analysis module for being controlled by the analysis module.