Localized Electrochemical Deposition of Copper Microstructures

This work demonstrates the electrodeposition of micrometer‐scale copper structures using a simple instrument based on the scanning electrochemical microscope (SECM). Copper columns of 25 μm width up to about 2 mm high were deposited on different substrates and interconnects were grown within an integrated circuit package. In the present instrument electrodeposition is localized by applying a voltage between a closely spaced glass insulated Pt disk ultramicroelectrode, ca. 25 μm diam, and a substrate, all immersed in a solution of acidified . The potential, the concentration of the , and the presence of organic additives were all found to affect the microstructure of the deposits and control the efficiency of the deposition. To demonstrate some of the possible applications of this technique, copper lines were grown between pads in an integrated circuit package and an antenna about 2 cm long was grown on a millimeter wave transmission line cantilever. © 2000 The Electrochemical Society. All rights reserved.