Structural characteristics of bright copper surfaces

In this work, the structures of copper surfaces polished mechanically and polished both mechanically and electrochemically, as well as copper coatings obtained in the presence of basic and top brightening addition agents were examined and compared with the structure of a silver mirror. It was shown by the STM technique that the structural characteristics important for the mirror brightness of the copper surface polished both mechanically and electrochemically and the copper coating are: (1) flat and mutually parallel parts of the surface which are smooth on the atomic level and (2) distances between adjacent flat parts are comparative with the distances between the adjacent flat parts of a silver mirror. Also, on the basis of the STM analysis, a mathematical model treating brightness from the point of view of geometrical optics was developed. X-ray diffraction analysis of the copper surfaces showed that mirror brightness is not associated directly with the degree of preferred orientation. (C) 2001 Elsevier Science B.V. All rights reserved.