Has anybody published information on the automated control of copper sulfate plating solutions? G.W.
There is a lot of activity in automating the control of plating baths. The big driver for this activity is the electronics industry. In the case of the copper sulfate bath, better control of the plating bath is needed for the printed wire board industry and for the deposition of copper on semiconductor silicon wafers. Certainly the concept is simple and straightforward: Monitor concentrations of various bath components in real time and use the results to add various components to the bath in real time. A number of monitoring methods have been developed with cyclic voltametric stripping (CVS) being the most common. Ion chromatography is another method that offers much promise.
There are a number of papers that have been published that discuss automated control of plating baths. One that is specific to the semiconductor industry is Dordi and Hey, "Automated Chemical Management for Production Copper Electroplating," Semiconductor Fabtech, 11th ed. There are a number of papers listed in the database of the Printed Wiring Board Research Center, www.pwbrc.org.
Sources for CVS equipment and ion chromatography equipment can be found under Analytical Equipment, automatic solution titration and Analytical Equipment, ion chromatography on the Suppliers page at www.pfonline.com or in the 2001 Products Finishing Directory & Technology Guide.