<s>
Dry	B-Algorithm
etching	I-Algorithm
refers	O
to	O
the	O
removal	O
of	O
material	O
,	O
typically	O
a	O
masked	O
pattern	O
of	O
semiconductor	O
material	O
,	O
by	O
exposing	O
the	O
material	O
to	O
a	O
bombardment	O
of	O
ions	O
(	O
usually	O
a	O
plasma	O
of	O
reactive	O
gases	O
such	O
as	O
fluorocarbons	O
,	O
oxygen	O
,	O
chlorine	O
,	O
boron	O
trichloride	O
;	O
sometimes	O
with	O
addition	O
of	O
nitrogen	O
,	O
argon	O
,	O
helium	O
and	O
other	O
gases	O
)	O
that	O
dislodge	O
portions	O
of	O
the	O
material	O
from	O
the	O
exposed	O
surface	O
.	O
</s>
<s>
A	O
common	O
type	O
of	O
dry	B-Algorithm
etching	I-Algorithm
is	O
reactive-ion	B-Algorithm
etching	I-Algorithm
.	O
</s>
<s>
Unlike	O
with	O
many	O
(	O
but	O
not	O
all	O
,	O
see	O
isotropic	O
etching	B-Algorithm
)	O
of	O
the	O
wet	O
chemical	O
etchants	O
used	O
in	O
wet	B-Algorithm
etching	I-Algorithm
,	O
the	O
dry	B-Algorithm
etching	I-Algorithm
process	O
typically	O
etches	O
directionally	O
or	O
anisotropically	O
.	O
</s>
<s>
Dry	B-Algorithm
etching	I-Algorithm
is	O
used	O
in	O
conjunction	O
with	O
photolithographic	B-Algorithm
techniques	O
to	O
attack	O
certain	O
areas	O
of	O
a	O
semiconductor	O
surface	O
in	O
order	O
to	O
form	O
recesses	O
in	O
material	O
.	O
</s>
<s>
Along	O
with	O
semiconductor	B-Architecture
manufacturing	I-Architecture
,	O
micromachining	B-Architecture
and	O
display	O
production	O
,	O
the	O
removal	O
of	O
organic	O
residues	O
by	O
oxygen	O
plasmas	O
is	O
sometimes	O
correctly	O
described	O
as	O
a	O
dry	O
etch	O
process	O
.	O
</s>
<s>
Dry	B-Algorithm
etching	I-Algorithm
is	O
particularly	O
useful	O
for	O
materials	O
and	O
semiconductors	O
which	O
are	O
chemically	O
resistant	O
and	O
could	O
not	O
be	O
wet	O
etched	O
,	O
such	O
as	O
silicon	O
carbide	O
or	O
gallium	O
nitride	O
.	O
</s>
<s>
Additionally	O
,	O
dry	O
etch	O
equipment	O
tends	O
to	O
be	O
an	O
order	O
of	O
magnitude	O
cheaper	O
than	O
photolithography	B-Algorithm
equipment	O
,	O
so	O
many	O
manufacturers	O
rely	O
on	O
dry	B-Algorithm
etching	I-Algorithm
strategies	O
such	O
as	O
pitch	O
doubling	O
or	O
quartering	O
to	O
gain	O
advanced	O
resolutions	O
(	O
14nm+	O
)	O
while	O
needing	O
less	O
advanced	O
photolithography	B-Algorithm
tools	O
.	O
</s>
<s>
Dry	B-Algorithm
etching	I-Algorithm
is	O
currently	O
used	O
in	O
semiconductor	B-Architecture
fabrication	I-Architecture
processes	O
due	O
to	O
its	O
unique	O
ability	O
over	O
wet	O
etch	O
to	O
do	O
anisotropic	O
etching	B-Algorithm
(	O
removal	O
of	O
material	O
)	O
to	O
create	O
high	O
aspect	O
ratio	O
structures	O
(	O
e.g.	O
</s>
<s>
The	O
dry	B-Algorithm
etching	I-Algorithm
hardware	O
design	O
basically	O
involves	O
a	O
vacuum	O
chamber	O
,	O
special	O
gas	O
delivery	O
system	O
,	O
radio	O
frequency	O
(	O
RF	O
)	O
waveform	O
generator	O
to	O
supply	O
power	O
to	O
the	O
plasma	O
,	O
heated	O
chuck	O
to	O
seat	O
the	O
wafer	O
,	O
and	O
an	O
exhaust	O
system	O
.	O
</s>
<s>
Dry	B-Algorithm
etching	I-Algorithm
process	O
was	O
invented	O
by	O
Stephen	O
M	O
.	O
Irving	O
who	O
also	O
invented	O
the	O
plasma	B-Algorithm
etching	I-Algorithm
process	I-Algorithm
.	O
</s>
<s>
The	O
anisotropic	O
dry	B-Algorithm
etching	I-Algorithm
process	O
was	O
developed	O
by	O
Hwa-Nien	O
Yu	O
at	O
the	O
IBM	O
T.J.	O
Watson	O
Research	O
Center	O
in	O
the	O
early	O
1970s	O
.	O
</s>
<s>
It	O
was	O
used	O
by	O
Yu	O
with	O
Robert	O
H	O
.	O
Dennard	O
to	O
fabricate	B-Architecture
the	O
first	O
micron-scale	B-Algorithm
MOSFETs	B-Architecture
(	O
metal	B-Architecture
–	I-Architecture
oxide	I-Architecture
–	I-Architecture
semiconductor	I-Architecture
field-effect	I-Architecture
transistors	I-Architecture
)	O
in	O
the	O
1970s	O
.	O
</s>
