Submicrometer platinum electrodes by through-mask plating

A through-mask electroplating process is described for forming Pt electrode structures with the vertical sidewalls and submicrometer dimensions desire d for dynamic random access memory applications. The plating process used a n aqueous KOH-based solution of "Pt A Salt'' (Engelhard) and a sputter-depo sited Pt plating base. Plating conditions were first optimized for blanket films on 200 mm diam wafers by examining the characteristics of the Pt depo sits as a function of plating bath temperature and current density. Electro de features were then formed on similar wafers by plating through a pattern ed SiO2 mask. Integration issues discussed include potential reactions of t he dielectric mask with the underlying Pt plating base, surface modificatio n of the exposed Pt plating base prior to plating, and erosion of the diele ctric mask by the plating solution. (C) 2001 The Electrochemical Society.