Design analysis of an electroless plating bath using CFD technique

The fluid field of the electroless plating bath was modeled and analyzed using a computational fluid dynamics (CFD) tool. By solving continuity and momentum equations, the pressure and velocity distributions in the plating bath were predicted. The analysis was performed under various design options: flow direction, flow rate, diffuser plate design, and wafer cassette design. It was found that the downward flow option delivers more uniform flow than the upward flow option. Flow pattern was similar among different flowrates and diffuser designs. Low velocity flow always existed at the top portion of the wafer and near the last row of the wafer cassette. With the hypothesis that slower flowrate results in higher plating rate; a qualitative agreement has been observed between the predicted flow pattern and the plated nickel height uniformity.