The impact of linewidth and line density on the texture of electroplated Cu in Damascene-fabricated lines

Effects of linewidth and line area density on the texture of chemical mecha nical polished Damascene-fabricated Cu-filled isolation trenches are studie d. Texture evaluated by electron backscatter diffraction was found to be im pacted by both. For linewidths of 1.4 and 11.2 mu m, there was a strong imp rovement in (111) fiber texture as linewidth increased. For line area densi ties of 40 and 57%, there was a less strong though significant decrease of the (111) texture as the line area density increased. We suggest a reason f or these texture variations based on the influence of the geometrical const raints during Cu deposition. The chemical mechanical polishing removal rate showed a difference of 30% between electroplated Cu with a poor texture an d one with a strong texture, implying that localized texture variations can lead to localized nonuniformity during chemical mechanical polishing. (C) 1999 The Electrochemical Society. S1099-0062(98)10-005-0. All rights reserv ed.