Coherent x-ray diffraction measurements of Cu thin lines

1-μm-thick Cu thin lines with adjacent connections, which simulate via structures in large-scale integration circuits, were fabricated on Si ₃N₄ membranes by both electron-beam evaporation and a focused ion beam for coherent x-ray diffraction measurements. A direct current was applied to a Cu thin line to prepare an electromigration sample. In the scanning electron microscope image of the electromigration sample, a roughness of a few hundred nanometers was observed on the surface around the via structures. Coherent x-ray diffraction patterns of both the thin line and electromigration samples were measured using synchrotron x-rays at SPring-8. Characteristic diffraction patterns resulting from both the shape of the Cu thin lines and the defects around the via structures formed by the application of the current were observed.