Electrochimica Acta, Vol.55, No.5, 1656-1663, 2010
Seedless copper electroplating on Ta from a "single" electrolytic bath
An alternative approach for copper electroplating on Ta surface from a "single" injected bath is being described in this work. Copper electrodeposition over a thin TaN/Ta barrier was performed in a two-step process: (1) activation conducted by electrochemically reduction of Ta oxide from the TaN/Ta barrier at a negative potential of -2 V for a short period ("removal" step) and (2) copper electroplating performed in the invariable electrochemical bath by injecting a solution containing Cu-ions. Supplementary Cu plating is continued by shifting the applied potential to -1.2 V in the same electrolytic bath. It was also established that addition of low content (up to 10 ppm) dimercaptothiadiazole (DMcT) improves Cu nucleation and growth on Ta surface and allows a conformal features fillings. Copper layer deposited is characterized with an excellent adhesion to the Ta surface. (C) 2009 Elsevier Ltd. All rights reserved.