Microstructure and texture of free-standing Cu-line patterns

Abstract

Free-standing discontinuous Cu-line patterns varying in line widths and interline distances in the range of a few micrometers were manufactured by combining photolithography and electrochemical deposition. Two principally different seed layers, polycrystalline Au and X-ray amorphous Ni-P, were applied prior to electrodeposition of the Cu lines as well as continuous Cu films, which were deposited as reference. The effect of the seed layer and the influence of the pattern design on surface topography and morphology of the deposits were studied by means of light optical and scanning electron microscopy (SEM). The growth behavior is related to the developing crystallographic texture of Cu-line patterns and continuous films, as determined from calculated orientation distribution functions (ODFs) on the basis of X-ray diffraction (XRD) pole figure measurements. While strong crystallographic textures of Cu lines on polycrystalline Au were observed with pattern-dependent differences to continuous films, almost no preferred grain orientations develop both for Cu lines and corresponding continuous films deposited on amorphous Ni-P.