Programmable test socket

Details Programmable test socket Programmable test socket

2001-07-17

2004-01-13

Cuneo, Kamand (Department: 2829)

Electricity: measuring and testing

Fault detecting in electric circuits and of electric components

Of individual circuit component or element

C324S537000, C324S1540PB

Reexamination Certificate

active

06677770

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to test sockets for semiconductor devices, such as ball grid array semiconductor packages, chip scale semiconductor packages, integrated circuit devices, etc. More particularly, the present invention relates to a test socket including an interchangeable guide plate that may be removed without substantial maintenance actions.
With reference to
FIG. 1
, a side view of a conventional test socket
10
is shown. The test socket
10
is used to receive successive semiconductor devices
12
in order to perform various quality assurance tests, such as electrical performance tests. The semiconductor devices
12
typically include a plurality of electrical terminals
14
that are electrically connected to operative circuitry of the device. In end use, the electrical terminals
14
of the semiconductor devices
12
are soldered to corresponding terminals (or pads) of a printed circuit board in order to access the functionality of the operative circuitry. The soldering process, however, permanently deforms the electrical terminals
14
of the semiconductor devices
12
and, therefore, is an unsuitable process for use during quality assurance testing. Further, the soldering process is not suitable when bare semiconductor chips (or dice) are subject to quality assurance tests.
The test socket
10
is capable of releasably receiving the semiconductor devices
12
and biasing the electrical terminals
14
thereof against corresponding terminals of a printed circuit board
20
without significant permanent deformation of the electrical terminals
14
. Thus, quality assurance tests may be performed on a given semiconductor device
12
while in the test socket
10
and the semiconductor device
12
may be subsequently removed without suffering significant deformation.
With further reference to
FIG. 2
, which shows the test socket
10
decoupled from the printed circuit board
20
, the test socket
10
includes a guide plate
16
that engages the semiconductor device
12
and maintains the electrical terminals
14
of the semiconductor device
12
in registration with the corresponding electrical terminals of the printed circuit board
20
. In particular, the guide plate
16
includes a support structure
18
that engages a periphery of the semiconductor device
12
in order to maintain the semiconductor
12
in registration with the electrical terminals of the printed circuit board
20
. The dimensions of the support structure
18
are matched with the dimensions of the semiconductor device
12
. Therefore, when different sizes of semiconductor devices
12
are to be tested (as is common when non-standardized chip scale semiconductor packages are tested), the guide plate
16
must be changed. As best seen in
FIG. 2
, this entails decoupling the test socket
10
from the printed circuit board
20
. Indeed, the guide plate
16
is maintained in registration with the electrical terminals of the printed circuit board
20
by way of a peripheral flange
22
of the guide plate
16
and a corresponding undercut
24
of the test socket
10
. When the test socket
10
is coupled to the printed circuit board
20
(usually by way of machine screws, not shown) the undercut
24
biases the peripheral flange
22
of the guide plate
16
against the printed circuit board
20
.
The electrical terminals
14
of the semiconductor device
12
are biased against the corresponding electrical terminals of the printed circuit board
20
by way of latches
15
(or levers) that may releasably engage the semiconductor device
12
.
Unfortunately, the removal of the test socket
10
from the printed circuit board
20
involves a significant effort, as a technician must remove several machine screws, lift the test socket
10
, exchange the guide plate
16
, and then reassemble the components. This problem is exacerbated when the quality assurance process involves the use of hundreds of such test sockets
10
and a change in the dimensions of the semiconductor device
12
requires maintenance actions on hundreds of assemblies. These maintenance actions result in a loss of time and coinciding increase in costs associated with the quality assurance testing process.
Accordingly, there is a need in the art for a new test socket that is capable of receiving different sized semiconductor devices without requiring removal from an associated PC board or other substantial maintenance actions.
SUMMARY OF THE INVENTION
A test socket for a semiconductor device, includes: a guide plate operable to receive the semiconductor device and to maintain electrical terminals of the semiconductor device in registration with electrical terminals of a base; a shell operable to couple to the base and to maintain the guide plate in registration with the electrical terminals of the base, the shell including an aperture in communication with the base through which the guide plate can be inserted and removed when the shell is coupled to the base; and at least one fastener coupled to the shell and operable to maintain the semiconductor device in engagement with the guide plate and to urge the electrical terminals of the semiconductor device in contact with the electrical terminals of the base. Preferably, the base is a printed circuit board.
The guide plate may include a periphery, and the aperture may be transversely directed through the shell with respect to the base and include one or more inside surfaces that operatively engage the periphery of the guide plate to prevent substantial lateral movement of the guide plate with respect to the base but permit sliding egress of the guide plate away from the base and through the aperture.
Preferably, the at least one fastener is movable between at least first and second positions, the first position causing the at least one fastener to maintain the semiconductor device in engagement with the guide plate and to urge the electrical terminals of the semiconductor device in contact with the electrical terminals of the base, and the second position permitting removal of the semiconductor device from the test socket and egress of the guide plate from the aperture of the shell.
The test socket preferably further includes at least one stop member coupled to the guide plate and operable to engage the at least one fastener, when in the first position, such that the guide plate is maintained in the aperture of the shell. The at least one stop member may be formed from a compressible material such that the guide plate is resiliently urged toward the base when the at least one fastener is moved into the first position.
Preferably, the at least one fastener includes one or more levers, each including a proximal end hingedly coupled to the shell and a distal end such that the lever is rotatable between at least first and second positions, the first position causing the distal end of the lever to maintain the semiconductor device in engagement with the guide plate and to urge the electrical terminals of the semiconductor device in contact with the electrical terminals of the base, and the second position permitting removal of the semiconductor device from the test socket and egress of the guide plate from the aperture of the shell. The respective distal ends of the one or more levers may be operable to engage the semiconductor device and the at least one stop member of the guide plate when the one or more levers are in the first position. The respective one or more levers may be operable to engage the at least one stop member of the guide plate at an intermediate position between the proximal and distal ends thereof.
In accordance with one or more further aspects of the present invention, a method for using a test socket for a semiconductor device is disclosed. The test socket may comprise a shell coupled to a base, the shell having an aperture and being operable to maintain a guide plate in registration with electrical terminals of the base, the method comprising: inserting a guide plate into the aperture of the shell without decoupling the shell from the base, t

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