Plating accelerator is applied selectively to a substantially-unfilled
wide (e.g., low-aspect-ratio feature cavity. Then, plating of metal is
conducted to fill the wide feature cavity and to form an embossed
structure in which the height of a wide-feature metal protrusion over the
metal-filled wide-feature cavity is higher than the height of metal over
field regions. Most of the overburden metal is removed using non-contact
techniques, such as chemical wet etching. Metal above the wide feature
cavity protects the metal-filled wide-feature interconnect against
dishing, and improved planarization techniques avoid erosion of the metal
interconnect and dielectric insulating layer. In some embodiments,
plating of metal onto a substrate is conducted to fill narrow (e.g.,
high-aspect-ratio feature cavities) in the dielectric layer before
selective application of plating accelerator and filling of the wide
feature cavity.