The shift in strategy from Al to Cu interconnects and from conventional metal etching to a damascene, or in-laid, metal fabrication technique presents new challenges to understand how manufacturing conditions control the microstructure of copper interconnect features. The final microstructure of inlaid copper interconnects forms within the confined space of the pre-patterned dielectric, rather than within a 2-dimensional thin film. Epitaxial substrate effects from the trench bottom and sidewalls influence the developing microstructure depending on the interface energy with the barrier or adhesion layer, the feature width and depth, and the thermally induced stress conditions in subsequent processing. Electron backscatter diffraction has been used in a number of investigations of thin Cu films and lines to determine grain size and crystallographic texture. This work summarizes some of the information gleaned using EBSD about structural evolution in Cu films and lines. Also, the texture and grain size in single level Cu lines as a function of line width is presented and analyzed in the context of stress-state in the lines, and its effect on texture development.