<s>
A	O
probe	B-Algorithm
card	I-Algorithm
(	O
commonly	O
referred	O
to	O
as	O
a	O
DUT	O
board	O
)	O
is	O
used	O
in	O
automated	O
integrated	O
circuit	O
testing	O
.	O
</s>
<s>
It	O
is	O
an	O
interface	O
between	O
an	O
electronic	O
test	O
system	O
and	O
a	O
semiconductor	B-Architecture
wafer	I-Architecture
.	O
</s>
<s>
A	O
probe	B-Algorithm
card	I-Algorithm
or	O
DUT	O
board	O
is	O
a	O
printed	O
circuit	O
board	O
(	O
PCB	O
)	O
,	O
and	O
is	O
the	O
interface	O
between	O
the	O
integrated	O
circuit	O
and	O
a	O
test	O
head	O
,	O
which	O
in	O
turn	O
attaches	O
to	O
automatic	O
test	O
equipment	O
(	O
ATE	O
)	O
(	O
or	O
"	O
tester	O
"	O
)	O
.	O
</s>
<s>
Typically	O
,	O
the	O
probe	B-Algorithm
card	I-Algorithm
is	O
mechanically	O
docked	O
to	O
a	O
Wafer	B-Algorithm
testing	I-Algorithm
prober	O
and	O
electrically	O
connected	O
to	O
the	O
ATE	O
.	O
</s>
<s>
Its	O
purpose	O
is	O
to	O
provide	O
an	O
electrical	O
path	O
between	O
the	O
test	O
system	O
and	O
the	O
circuits	O
on	O
the	O
wafer	B-Architecture
,	O
thereby	O
permitting	O
the	O
testing	O
and	O
validation	O
of	O
the	O
circuits	O
at	O
the	O
wafer	B-Architecture
level	O
,	O
usually	O
before	O
they	O
are	O
diced	O
and	O
packaged	B-Algorithm
.	O
</s>
<s>
A	O
semiconductor	O
manufacturer	O
will	O
typically	O
require	O
a	O
new	O
probe	B-Algorithm
card	I-Algorithm
for	O
each	O
new	O
device	O
wafer	B-Architecture
and	O
for	O
device	O
shrinks	O
(	O
when	O
the	O
manufacturer	O
reduces	O
the	O
size	O
of	O
the	O
device	O
while	O
keeping	O
its	O
functionality	O
)	O
because	O
the	O
probe	B-Algorithm
card	I-Algorithm
is	O
effectively	O
a	O
custom	O
connector	O
that	O
takes	O
the	O
universal	O
pattern	O
of	O
a	O
given	O
tester	O
and	O
translates	O
the	O
signals	O
to	O
connect	O
to	O
electrical	O
pads	O
on	O
the	O
wafer	B-Architecture
.	O
</s>
<s>
For	O
testing	O
of	O
Dynamic	O
random-access	O
memory	O
(	O
DRAM	O
)	O
and	O
Flash	B-Device
memory	I-Device
(	O
FLASH	O
)	O
devices	O
,	O
these	O
pads	O
are	O
typically	O
made	O
of	O
aluminum	O
and	O
are	O
40	O
–	O
90	O
per	O
side	O
.	O
</s>
<s>
The	O
probe	B-Algorithm
card	I-Algorithm
must	O
make	O
good	O
electrical	O
contact	O
to	O
these	O
pads	O
or	O
bumps	O
during	O
the	O
testing	O
of	O
the	O
device	O
.	O
</s>
<s>
When	O
the	O
testing	O
of	O
the	O
device	O
is	O
complete	O
,	O
the	O
prober	O
will	O
index	O
the	O
wafer	B-Architecture
to	O
the	O
next	O
device	O
to	O
be	O
tested	O
.	O
</s>
<s>
Normally	O
a	O
probe	B-Algorithm
card	I-Algorithm
is	O
inserted	O
into	O
a	O
wafer	B-Architecture
prober	O
,	O
inside	O
which	O
the	O
position	O
of	O
the	O
wafer	B-Architecture
to	O
be	O
tested	O
will	O
be	O
adjusted	O
to	O
ensure	O
a	O
precise	O
contact	O
between	O
the	O
probe	B-Algorithm
card	I-Algorithm
and	O
wafer	B-Architecture
.	O
</s>
<s>
Once	O
the	O
probe	B-Algorithm
card	I-Algorithm
and	O
the	O
wafer	B-Architecture
are	O
loaded	O
,	O
a	O
camera	O
in	O
the	O
prober	O
will	O
optically	O
locate	O
several	O
tips	O
on	O
the	O
probe	B-Algorithm
card	I-Algorithm
and	O
several	O
marks	O
or	O
pads	O
on	O
the	O
wafer	B-Architecture
,	O
and	O
using	O
this	O
information	O
it	O
will	O
align	O
the	O
pads	O
on	O
the	O
device	O
under	O
test	O
(	O
DUT	O
)	O
to	O
the	O
probe	B-Algorithm
card	I-Algorithm
contacts	O
.	O
</s>
<s>
Probe	B-Algorithm
cards	I-Algorithm
are	O
broadly	O
classified	O
into	O
needle	O
type	O
,	O
vertical	O
type	O
,	O
and	O
MEMS	B-Architecture
(	O
Micro	O
Electro-Mechanical	O
System	O
)	O
type	O
depending	O
on	O
shape	O
and	O
forms	O
of	O
contact	O
elements	O
.	O
</s>
<s>
MEMS	B-Architecture
type	O
is	O
the	O
most	O
advanced	O
technology	O
currently	O
available	O
.	O
</s>
<s>
The	O
most	O
advanced	O
type	O
of	O
probe	B-Algorithm
card	I-Algorithm
currently	O
can	O
test	O
an	O
entire	O
12	O
"	O
wafer	B-Architecture
with	O
one	O
touchdown	O
.	O
</s>
<s>
Probe	B-Algorithm
cards	I-Algorithm
or	O
DUT	O
boards	O
are	O
designed	O
to	O
meet	O
both	O
the	O
mechanical	O
and	O
electrical	O
requirements	O
of	O
the	O
particular	O
chip	O
and	O
the	O
specific	O
test	O
equipment	O
to	O
be	O
used	O
.	O
</s>
<s>
One	O
type	O
of	O
DUT	O
board	O
is	O
used	O
for	O
testing	O
the	O
individual	O
die	O
of	O
a	O
silicon	B-Architecture
wafer	I-Architecture
before	O
they	O
are	O
cut	O
free	O
and	O
packaged	B-Algorithm
,	O
and	O
another	O
type	O
is	O
used	O
for	O
testing	O
packaged	B-Algorithm
IC	O
's	O
.	O
</s>
<s>
Probe	B-Algorithm
card	I-Algorithm
efficiency	O
is	O
affected	O
by	O
many	O
factors	O
.	O
</s>
<s>
Perhaps	O
the	O
most	O
important	O
factor	O
impacting	O
probe	B-Algorithm
card	I-Algorithm
efficiency	O
is	O
the	O
number	O
of	O
DUTs	O
that	O
can	O
be	O
tested	O
in	O
parallel	O
.	O
</s>
<s>
Many	O
wafers	B-Architecture
today	O
are	O
still	O
tested	O
one	O
device	O
at	O
a	O
time	O
.	O
</s>
<s>
If	O
one	O
wafer	B-Architecture
had	O
1000	O
of	O
these	O
devices	O
and	O
the	O
time	O
required	O
to	O
test	O
one	O
device	O
was	O
10	O
seconds	O
and	O
the	O
time	O
for	O
the	O
prober	O
to	O
move	O
from	O
one	O
device	O
to	O
another	O
device	O
was	O
1	O
second	O
,	O
then	O
to	O
test	O
an	O
entire	O
wafer	B-Architecture
would	O
take	O
1000	O
x	O
11	O
seconds	O
=	O
11,000	O
seconds	O
or	O
roughly	O
3	O
hours	O
.	O
</s>
<s>
If	O
however	O
,	O
the	O
probe	B-Algorithm
card	I-Algorithm
and	O
the	O
tester	O
could	O
test	O
16	O
devices	O
in	O
parallel	O
(	O
with	O
16	O
times	O
the	O
electrical	O
connections	O
)	O
then	O
the	O
test	O
time	O
would	O
be	O
reduced	O
by	O
almost	O
exactly	O
16	O
times	O
(	O
to	O
about	O
11	O
minutes	O
)	O
.	O
</s>
<s>
Normally	O
these	O
are	O
made	O
of	O
tungsten	B-Application
or	O
tungsten/rhenium	O
alloys	O
or	O
advanced	O
palladium	O
based	O
alloys	O
like	O
PdCuAg	O
.	O
</s>
<s>
Some	O
modern	O
probe	B-Algorithm
cards	I-Algorithm
have	O
contact	O
tips	O
manufactured	O
by	O
MEMS	B-Architecture
technologies	O
.	O
</s>
<s>
To	O
return	O
a	O
used	O
probe	B-Algorithm
card	I-Algorithm
to	O
a	O
contact	O
resistance	O
that	O
is	O
acceptable	O
,	O
the	O
probe	O
tips	O
must	O
be	O
spotless	O
.	O
</s>
<s>
Online	O
cleaning	O
can	O
be	O
used	O
during	O
testing	O
to	O
optimize	O
the	O
testing	O
results	O
within	O
the	O
wafer	B-Architecture
or	O
within	O
wafer	B-Architecture
lots	O
.	O
</s>
