An accelerator solution is globally applied to a workpiece to form an
accelerator film, and then a portion of the accelerator film is
selectively removed from the workpiece to form an acceleration region
having a higher concentration of accelerator. The higher concentration of
accelerator causes metal to deposit at a faster rate in the acceleration
region than in a non-accelerated region for the duration of metal
deposition. To make a metal feature, a resist layer is applied to a
workpiece surface and patterned to form a recessed region and a field
region. Then, a metal seed layer is deposited on the workpiece surface.
An accelerator solution is applied so that an accelerator film forms on
the metal seed layer. A portion of the accelerator film is selectively
removed from the field region, leaving another portion of the accelerator
film in the recessed region. Then, copper is electroplated onto the
workpiece, and the copper plates at an accelerated rate in the recessed
region, resulting in a greater thickness of copper in the recessed region
compared to copper in the field region. A wet etch is performed to remove
copper from the field region. Then, the resist is removed from the field
region, resulting in a coarse copper wire.