<s>
Optical	B-Algorithm
proximity	I-Algorithm
correction	I-Algorithm
(	O
OPC	O
)	O
is	O
a	O
photolithography	B-Algorithm
enhancement	O
technique	O
commonly	O
used	O
to	O
compensate	O
for	O
image	O
errors	O
due	O
to	O
diffraction	O
or	O
process	O
effects	O
.	O
</s>
<s>
These	O
projected	O
images	O
appear	O
with	O
irregularities	O
such	O
as	O
line	O
widths	O
that	O
are	O
narrower	O
or	O
wider	O
than	O
designed	O
,	O
these	O
are	O
amenable	O
to	O
compensation	O
by	O
changing	O
the	O
pattern	O
on	O
the	O
photomask	B-Algorithm
used	O
for	O
imaging	O
.	O
</s>
<s>
Optical	B-Algorithm
proximity	I-Algorithm
correction	I-Algorithm
corrects	O
these	O
errors	O
by	O
moving	O
edges	O
or	O
adding	O
extra	O
polygons	O
to	O
the	O
pattern	O
written	O
on	O
the	O
photomask	B-Algorithm
.	O
</s>
<s>
For	O
the	O
former	O
case	O
,	O
this	O
may	O
be	O
used	O
together	O
with	O
resolution	B-Algorithm
enhancement	I-Algorithm
technologies	I-Algorithm
such	O
as	O
scattering	O
bars	O
(	O
sub-resolution	O
lines	O
placed	O
adjacent	O
to	O
resolvable	O
lines	O
)	O
together	O
with	O
linewidth	O
adjustments	O
.	O
</s>
<s>
OPC	O
has	O
a	O
cost	O
impact	O
on	O
photomask	B-Algorithm
fabrication	O
whereby	O
the	O
mask	O
write	O
time	O
is	O
related	O
to	O
the	O
complexity	O
of	O
the	O
mask	O
and	O
data-files	O
and	O
similarly	O
mask	O
inspection	O
for	O
defects	O
takes	O
longer	O
as	O
the	O
finer	O
edge	O
control	O
requires	O
a	O
smaller	O
spot	O
size	O
.	O
</s>
<s>
This	O
is	O
the	O
case	O
for	O
the	O
complementary	O
photomask	B-Algorithm
technique	O
,	O
where	O
the	O
images	O
of	O
an	O
alternating-aperture	O
phase-shifting	B-Algorithm
mask	I-Algorithm
and	O
a	O
conventional	O
binary	O
mask	O
are	O
added	O
together	O
.	O
</s>
<s>
In	O
contrast	O
to	O
multiple	O
exposure	O
of	O
the	O
same	O
photoresist	O
film	O
,	O
multiple	B-Algorithm
layer	I-Algorithm
patterning	I-Algorithm
entails	O
repeated	O
photoresist	O
coating	O
,	O
deposition	O
,	O
and	O
etching	O
to	O
pattern	O
the	O
same	O
device	O
layer	O
.	O
</s>
<s>
For	O
example	O
,	O
proximity	B-Algorithm
effect	I-Algorithm
correction	O
in	O
electron	B-Architecture
beam	I-Architecture
lithography	I-Architecture
is	O
included	O
as	O
an	O
automated	O
capability	O
on	O
commercial	O
electron-beam	B-Architecture
lithography	I-Architecture
tools	O
.	O
</s>
<s>
Since	O
many	O
non-lithographic	O
processes	O
exhibit	O
their	O
own	O
proximity	B-Algorithm
effects	I-Algorithm
,	O
e.g.	O
,	O
chemical-mechanical	B-Algorithm
polishing	I-Algorithm
or	O
plasma	B-Algorithm
etching	I-Algorithm
,	O
these	O
effects	O
can	O
be	O
mixed	O
in	O
with	O
the	O
original	O
OPC	O
.	O
</s>
