Contactors/Sockets - Page 2 of 3
The
motion of the contact
element as it comes into contact with the lead is another factor in
selecting a good contactor. Old contactor designs simply push the
contact elements against the leads to make the contact. New contactor
designs give the contact elements a
‘wiping’ action, so that contaminants,
oxides, and residues on the DUT lead will first be removed before the
final contact is made.
Fig. 2.
More examples of contactors
Ease of maintaining,
replacing, or configuring a contactor
is another consideration when looking for a good contactor.
Contact elements
degrade
with usage, and should therefore be monitored and maintained
regularly.
It should be promptly
replaced
once it has exhausted its useful life, since poor contact caused by
worn-out contact elements can result in a lot of test issues.
Well-designed contactors should be able to do several hundreds of
thousands of contact cycles within its lifetime.
The electrical
characteristics of the contactor is also critical in ensuring the
integrity of the test process. Contact resistance, stray capacitance,
and stray inductance, as well as capacitive and inductive coupling must
all be minimized. The dimensions, shapes, and material of the various
features of a contactor as well as the contact area and tip topography
of the contact element all affect the electrical performance of a
contactor.
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Fig. 3.
Examples of sockets
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The
term 'contactor' is also used to refer to
sockets employed to get convenient electrical
access to the DUT, especially if the DUT is a fine-pitch, high-pin count
complex device. Sockets are often used for hand-testing DUT's or
in failure analysis. The fine-pitched device is simply inserted
into the socket, which has leads that correspond to those of the device
but more widely-spaced for convenient electrical access. In some cases, the contactor used in
the contactor block may also serve as a socket on its own.
Examples of manufacturers of
contactors are Johnstech International, Dimensions Consulting Inc. (DCI) and Kulicke and Soffa
(K&S).
<Back to Page 1 - Contactors>
<Proceed to Page 3 - Manufacturers: DCI and
K&S>
See also:
Test
Accessories;
Test Equipment;
Electrical Testing;
Semiconductor
Manufacturing
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