Electron backscattered diffraction analysis of copper damascene interconnect for ultralarge-scale integration

This study focuses on the structures and the crystallographic orientations of copper electrodeposits in trench patterns by the electron backscattered diffraction (EBSD) technique. The EBSD measurement was made on the surface of annealed deposits before and after removal of their over-plated layers by chemical mechanical polishing (CMP) and also on the section normal to trench lines. The textures of the annealed deposit with and without the over-plated layer are almost same. The major and minor orientation components in the annealing textures of trench specimens were approximated by {111}〈110〉 and its twin components, {115}〈110〉 and {115}〈141〉, respectively. Here {hkl}〈uvw〉 indicates that {hkl} is the crystallographic planes parallel to the trench base plane and 〈uvw〉 is the crystallographic directions parallel to the trench line direction. By measuring the line-normal sectional EBSD analysis, the copper electrodeposit in a trench plug is figured as a single crystal having a few of twinning, and hence the over-plated layer has almost the same texture as the trench plug. Therefore, the texture of trench plugs can be inferred by that of the over-plated layer.