Mass transfer of an impinging jet confined between parallel plates

An understanding of the mass transfer behavior of an impinging jet can be usefully applied to wet chemical processes such as water rinsing, photoresist development, and metal etching or plating. Theoretical and experimental methods were used to study the mass transfer characteristics of an axisymmetric impinging jet confined between two parallel plates. Such a configuration was used because of its potential applicability to the fabrication of printed wiring boards. The CFD (computational fluid dynamics) method was used to model fluid flow and mass transfer. An electrochemical probe based on the ferro-ferricyanide system was used to experimentally determine the mass transfer coefficients and to evaluate the applicability of the theoretical methods used. An etching method was used to characterize the mass transfer rates in a typical cupric chloride etching solution. A new observation of the effect of jet instability on the etching rate in the central impingement zone is discussed.