Abstract: A method for detecting contamination of a bath of electrolyte in an electroplating processor is performed by preparing a baseline plot using chronopotentiometry of a baseline sample of electrolyte having substantially the same chemical composition as the initial clean bath of the processor. A sample of the presently existing plating electrolyte from the processor is obtained. A processor sample plot is prepared using chronopotentiometry of the sample of plating electrolyte obtained from the processor. The baseline plot is compared to the processor sample plot. A substantial match between them indicates no contamination in the bath. Divergence between them indicates contamination in the bath. A library of contamination chronopotentiometric signatures may be used to test the bath.

Abstract: A method for electroplating a wafer detects plating bath failure based on a voltage change. The method is useful in plating wafers having TSV features. Voltage of each anode of a plating processor may be monitored. An abrupt drop in voltage signals a bath failure resulting from conversion of an accelerator such as SPS to it's by products MPS. Bath failure is delayed or avoided by current pulsing or current ramping. An improved plating bath has a catholyte with a very low acid concentration.