A method of patterning a metal layer in a semiconductor die comprises forming
a
mask on the metal layer to define an open region and a dense region. The method
further comprises etching the metal layer at a first etch rate to form a number
of metal segments in the open region and etching the metal layer at a second etch
rate to form a number of metal segments in the dense region, where the first etch
rate is approximately equal to the second etch rate. The method further comprises
performing a number of strip/passivate cycles to remove a polymer formed on sidewalls
of the metal segments in the dense region. The sidewalls of the metal segments
in the dense region undergo substantially no undercutting and residue is removed
from the sidewalls of the metal segments in the dense region.
