Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
2001-08-02
2003-01-07
Karlsen, Ernest (Department: 2829)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S761010
Reexamination Certificate
active
06504390
ABSTRACT:
TECHNICAL FIELD
The present invention relates to conductive bump array contactors having an ejector and methods for testing bumped devices using such apparatus, suitable for use with, for example, bumped die, chip scale packages, multi-chip modules, and the like.
BACKGROUND OF THE INVENTION
Bumped die and other bumped devices are widely used throughout the electronics industry. As the drive toward smaller electronics continues, the pitch (or spacing) of the conductive bumps on bumped devices continues to decrease. The increasingly finer pitches of the conductive bumps raise concerns about the reliability of these devices, placing greater emphasis on the accuracy and efficiency-of bumped device testing.
FIG. 1
is an isometric view of a conventional conductive bump array contactor
10
that may be used to test a bumped device
20
(commonly referred to as a Device Under Test or DUT) having an array of conductive bumps
22
. The bumped device
20
includes a substrate layer
24
and an encapsulating layer
26
. The array contactor
10
includes a base
12
having a plurality of cylindrical apertures
14
disposed therethrough. A spring probe
16
is disposed within each aperture
14
, each spring probe having a first end
15
and a second end
17
. The first end
15
may be flush with, or extend slightly from, a top opening
18
of the aperture
14
. Similarly, the second end
17
may be flush with. or extend slightly from. a bottom opening
19
of the aperture
14
. Conductive bump array contactors
10
of the type shown in
FIG. 1
are described in U.S. Pat. No. 5,570,033 to Staab.
During testing, the bumped device is positioned over the base
12
with the conductive bumps
22
aligned with the openings
18
. The bumped device
20
engages the base
12
so that each of the conductive bumps
22
is in contact with the first end
15
of one of the spring probes
16
. The bumped device
20
may be pressed against the base
12
so that the first ends
15
are at least partially compressed into the spring probes
16
. The second ends
19
may then engage a plurality of contact pads of a test machine (not shown), which transmits test signals through one or more of the spring probes
16
to the bumped device
20
. The test machine may also receive output signals from the bumped device
20
to determine whether the bumped device
20
is performing according to specifications. After testing, the bumped device
20
may be disengaged from the conductive bump array contactor
10
, and another bumped device may be tested in the same manner.
Although desirable results have been achieved using the conductive bump array contractor
10
, problems may be encountered during separation of the bumped device
20
from the array contactor
10
. For example. while the conductive bumps
22
are in contact with the first ends
15
of the spring probes
16
. material from the conductive bumps
22
may migrate and become attached to the first ends
15
. This may cause the conductive bumps
22
to become stuck to the first ends
15
of the spring probes
16
. When one or more of the conductive bumps
22
becomes stuck to the spring probes
16
. the testing process may be delayed as additional time and effort is expended to disengage the bumped device
20
from the array contactor
10
.
The sticking or bonding of the conductive bumps
22
to the spring probes
16
occurs with increasing frequency as the number of tests using the array contactor
10
increases. Also. as the number of conductive bumps
22
on the bumped device
20
increases, the probability that more of the conductive bumps
22
will become stuck increases, further decreasing the speed and efficiency of the testing process.
An additional concern with the array contactor
10
is that the bumped device
20
may not be accurately aligned with the top openings
18
of the apertures
14
. If the conductive bumps
22
are not precisely aligned with the top openings
18
, the first ends
15
of the spring probes
16
may not properly contact the conductive bumps
22
, and the testing may provide inaccurate or unreliable results. As the pitch of the conductive bumps
22
decreases, the task of aligning the conductive bumps
22
with the spring probes
16
becomes more difficult.
SUMMARY OF THE INVENTION
The present invention relates to conductive bump array contactors having an ejector and methods for testing bumped devices using such apparatus. In one aspect of the invention, a conductive bump array contactor includes a base having a plurality of contact elements projecting therefrom. an ejector coupled to the base and moveable with respect to the base between a first position proximate the base and a second position spaced apart from the base. and a biasing device coupled to the base and to the ejector that asserts a biasing force on the ejector. The biasing force is sufficient to overcome a sticking or attractive force that may develop between the conductive bumps and the contact elements. thereby positively disengaging the conductive bumps from the contact elements after tests are performed. In one embodiment, the contact elements project into a single opening at least partially defined by the ejector. Alternately. the ejector includes a raised alignment member that engages the bumped device to align the conductive bumps with the contact elements.
In another aspect of the invention, an apparatus includes an ejection plate having a plurality of apertures alignable with the array of conductive bumps. each aperture having a receiving end sized to at least partially receive one of the conductive bumps when the bumped device is encaged with the ejection plate. The receiving ends provide improved alignment of the conductive bumps with the contact elements. The contact elements may be spring probes, or may be buckle-beam probes, or any other suitable contact members.
In yet another aspect of the invention, a method of testing a bumped device includes providing a base having a plurality of contact elements projecting therefrom, positioning an ejector at least partially between the base and the bumped device, aligning the array of conductive bumps with the plurality of contact elements, applying an engaging force to the bumped device to move the ejector toward the base and to move the array of conductive bumps into contact with the plurality of contact elements, transmitting test signals to the bumped device through at least some of the contact elements, and releasing the engaging force from the bumped device to allow the ejector to move away from the base, the ejector disengaging the array of conductive bumps from the plurality of contact elements. In this way, positive disengagement of the conductive bumps from the contact elements is achieved.
REFERENCES:
patent: 5015946 (1991-05-01), Janko
patent: 5419710 (1995-05-01), Pfaff
patent: 5500605 (1996-03-01), Chang
patent: 5518410 (1996-05-01), Masami
patent: 5955888 (1999-09-01), Frederickson et al.
patent: 6036503 (2000-03-01), Tsuchida
patent: 6066957 (2000-05-01), Van Loan et al.
patent: 6292003 (2001-09-01), Fredrickson et al.
Dorsey & Whitney LLP
Karlsen Ernest
Micro)n Technology, Inc.
LandOfFree
Conductive bump array contactors having an ejector and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Conductive bump array contactors having an ejector and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conductive bump array contactors having an ejector and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3062849