Analysis of copper plating baths-new developments

Industry announcements on the use of Cu wiring on semiconductor devices has set the stage for increased requirements for the purity, plating effectiveness and plating speed of electroplating bath chemicals. Increased requirements have also been set for monitoring and optimizing Cu electroplating baths used in the manufacture of these devices. Ion and metal-free high performance liquid chromatography provide the analytical capabilities to monitor plating and etch bath components, contaminants, and degradation products to help optimize the process and reduce the amount of waste. New Cu plating bath products are being introduced to meet the emerging needs of this application. The new products are desired to provide a fast, efficient fill for even the most challenging wafer terrain. This paper provides information on the improved analytical methodologies for evaluating these new electroplating products using ion and high performance liquid chromatography. Some typical applications for the analysis of electroplating baths are: (1) additive concentration determination; (2) individual component analysis; (3) contaminant analysis. In this paper, we discuss: (1) determination of the concentration of an additive to a Cu plating bath; (2) how ion and metal free liquid chromatography can monitor and optimize the relative "goodness" of a plating bath; (3) typical chromatography applications for plating baths.