This work systematically investigates damage of Cr film grown on Si, SiO2 or SiNx-topped Si substrates and the adhesive Cr layer in Cr/Au or Cr/Cu/Au multilayers by oxygen plasma ashing. When the microwave power and substrate temperature are set below the critical conditions, the oxygen plasma does not attack the Cr film. However, beyond the critical parameters, the Cr film is not secure in oxygen plasma. Without additional heating, the Cr films grown on Si substrate and on SiO2 and SiNx-topped Si substrate are etched by oxygen plasma under power >= 300 W and >= 200 W, respectively. When the substrate is heated up to 100 degrees C, a microwave power of 100 W is enough to remove the Cr film. The adhesive Cr layer in metal multilayers is untouched by oxygen plasma until the microwave power rises up to 400 W and the substrate is heated up to 100 degrees C, this could result from a thicker Cr2O3 layer. When subjected to energetic oxygen ions or radicals bombardment, the top Cr2O3 layer could be dissociated to volatile Cr oxides, and at the same time, the underneath Cr film is further oxidized as Cr2O3 and volatile Cr oxides, the thicker the Cr2O3 layer, the higher the resistance of the Cr film to attack by oxygen plasma. These studies provide an important guideline for avoiding damage of oxygen plasma to the device. (C) 2014 Elsevier B.V. All rights reserved.