Copper hydride formation in the electroless copper plating process: in situ X-ray diffraction evidence and electrochemical study

摘要

Copper hydride, CuH, has been shown by in situ X-ray diffraction method to form in the process of electroless copper deposition in alkaline solutions containing Cu-II complexes with tartrate and ammonia and borohydride, BH4-, as a reducing agent. The rate of possible chemical and electrochemical steps was measured and compared with the rate of autocatalytic Cu-II reduction process. Results indicate the existence of two process routes: (1) coupling of simultaneous electrochemical reactions of BH4- oxidation and Cu-II reduction with the enhancement of cathodic reaction due to H-2 evolution in anodic reaction, (2) electrochemical steps of Cu-II reduction to Cu-I and consecutive chemical steps of CuH formation and decomposition. The route including CuH intermediate gives a lower Cu deposition rate. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 15]