Pitch multiplied and non-pitch multiplied features of an integrated
circuit, e.g., features in the array, interface and periphery areas of
the integrated circuit, are formed by processing a substrate through a
mask. The mask is formed by patterning a photoresist layer which
simultaneously defines mask elements corresponding to features in the
array, interface and periphery areas of the integrated circuit. The
pattern is transferred to an amorphous carbon layer. Sidewall spacers are
formed on the sidewalls of the patterned amorphous carbon layer. A layer
of protective material is deposited and then patterned to expose mask
elements in the array region and in selected parts of the interface or
periphery areas. Amorphous carbon in the array region or other exposed
parts is removed, thereby leaving a pattern including free-standing,
pitch multiplied spacers in the array region. The protective material is
removed, leaving a pattern of pitch multiplied spacers in the array
region and non-pitch multiplied mask elements in the interface and
periphery areas. The pattern is transferred to a hard mask layer, through
which an underlying substrate is etched.