The hydrogen bromide (HBr) plasma-copper reaction, which is the base of a new copper etching process, has been studied. A high etch rate has been obtained with the reaction. Influences of process parameters, such as plasma exposure time, pressure, plasma power and substrate temperature, to the reaction process were explored. In addition to the reaction rate, we also investigated the relationship between the morphology and structure of the reaction product layer and the process condition. The results show that both the plasma-phase chemistry and the ion bombardment energy are important to the reaction. Mechanism for the HBr plasma-Cu reaction process was compared with that for the HCl or Cl-2 plasma-Cu reaction. The reaction product was characterized with X-ray photoemission spectroscopy and X-ray diffraction. These results are critical to the understanding of this new copper dry etching process. (C) 2003 Elsevier B.V. All rights reserved.