Electrical connectors – Coupling part with actuating means urging contact to move...
Reexamination Certificate
2001-06-26
2002-06-11
Bradley, P. Austin (Department: 2833)
Electrical connectors
Coupling part with actuating means urging contact to move...
C439S342000
Reexamination Certificate
active
06402537
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to electrical property and burn-in tests for electronic parts, such as integrated circuits, and more particularly to a socket for providing an electrical connection between each terminal of an electronic part and an external device for removably loading the electronic part in the socket so that the leads of the socket are electrically connected to the respective terminals of the electronic part.
BACKGROUND OF THE INVENTION
Generally, electronic parts such as IC packages, in which IC chips have been sealed with plastic, are subjected to a reliability test called an electric property test or a burn-in test prior to their shipment in order to distinguish between acceptable and unacceptable products.
In electric property tests, input and output characteristics of the IC chips, pulse properties, noise leeway, and the like are tested. In burn-in tests, on the other hand, IC packages that have passed the electric property test are arranged in an oven and are made to function at an elevated temperature, 125° centigrade, for instance, and under a source voltage which is approximately 20% higher than the rated value. Those IC packages which fail in the burn-in test are removed as being unacceptable and only those others which continue functioning properly are shipped out as acceptable products.
In recent years, BGA (Ball Grid Array) packages having terminals made of solder balls positioned on the lower side of the package in a selected matrix, e.g., a zigzag fashion, have become popular as a desirable surface-loading type IC package. A BGA package provides advantages including features in which the terminals can be widely set while maintaining small outer dimensions and that the terminals are sturdy and resistant to deformation when they are brought into contact with other parts.
BACKGROUND OF THE INVENTION
FIGS.
6
(
a
) and
6
(
b
) show a conventional socket for loading a BGA package for a burn-in test. Socket
101
has a square-shaped base
102
and a slider
103
for loading BGA package
100
is arranged for movement in a horizontal direction on the base. A cover
104
, having an opening
104
a
therein, is received at the top of base
102
. Cover
104
is vertically movable relative to base
102
by means of compression coil springs
105
. A through hole is formed in slider
103
and base
102
corresponding to each solder ball
100
a
of the BGA package. A respective contact
106
for electrical connection with each solder ball
100
a
of the BGA package is arranged to extend through the through holes of base
102
and slider
103
. Each contact
106
is made of an elongated metallic member with a pair of arms
106
a
and
106
b
facing upward. A protuberant part, not shown in the drawing, is provided on one arm of arms
106
a
and
106
b
(e.g., arm
106
a
) and, as this protuberant part engages the partition wall of slider
103
, arms
106
a
and
106
b
are adapted to open and close upon sliding motion of the slider. A sliding mechanism for moving slider
103
in a direction which is in parallel with the bottom wall of base
102
is provided on opposite sides of the slider. The sliding mechanism includes a generally L-shaped lever member
108
rotatably mounted on each end of a shaft
107
provided at one side of base
102
(the right side in the drawings) and the short arm
108
a
of lever member
108
is rotatably linked to shaft
109
disposed in a vertically extending slot in slider
103
and which extends in parallel relation with shaft
107
. A lever member
111
is rotatably mounted on each end of shaft
110
provided at the opposite side of base
102
and the tip of lever member
108
is slidingly attached by a pin
112
in a slot formed in each respective lever member
111
intermediate to its opposite ends. When cover
104
is not pressed, tip
111
a
of each lever member
111
is adapted to touch the protuberant part
104
b
of cover
104
. Compression coil springs
113
are located in the vicinity of shaft
110
for biasing the slider toward the right as seen in the drawings.
In a socket made as described above, when cover
104
is pressed down from the state shown in FIG.
6
(
a
) to the state shown in FIG.
6
(
b
), lever members
108
and
111
rotate toward base
102
and shaft
109
transfers motion to slider
103
in conformity with the movement of lever member
108
, thereby causing the slider to shift in the X-direction. As a result, arm
106
a
of the arms of each contact
106
starts opening due to engagement with the partition wall of slider
103
. If, in this state, BGA package
100
is inserted through the central opening
104
a
of cover
104
, BGA package
100
is positioned by guide
103
c
so that each solder ball
100
a
enters between arms
106
a
and
106
b
of a respective contact
106
.
When the downward force on cover
104
is removed, lever members
108
and
111
rise and slider
103
is returned in the X+ direction by the force of coil springs
113
and the stored force of the contact arms, with a result that arms
106
a
and
106
b
of each contact
106
are closed and each solder ball
100
a
of BGA package
100
is held by arms
106
a
and
106
b
of a respective contact
106
. Thus, each solder ball
100
a
of BGA package
100
is electrically connected to a respective contact
106
.
With respect to a conventional socket
101
as described above, the linkage mechanism comprising the lever members
108
and
111
, pin
112
and shafts
107
,
109
and
110
is used to move slider
103
. However, the number of parts involved is considerable and the construction becomes complicated, thereby requiring a number of assembly steps with concomitant assembly time before completion. Further, the use of the linkage mechanism adds to the size and weight of socket
101
making it larger and heavier than desired.
In copending applications, U.S. Ser. Nos. 09/694,636 and 09/850,622 filed respectively on Oct. 23, 2000 and May 7, 2001, and assigned to the assignee of the present invention, prior art linkage mechanisms of the type described are obviated by directly pressing the slider of the main socket body by means of a force applying member provided on a jig for loading the electronic part to be tested. The force applying member has a surface inclined at a selected angle and the force applying member of the jig is moved vertically toward and away from the socket, thereby making it possible for the slider of the main socket body to move in a direction normal to the movement of the force applying member, i.e., horizontal versus vertical directions.
In view of the fact that the amount of movement of the slider is therefore dependent upon the inclined angle of the force applying member of the jig that employs such a mechanism, there is a problem in that the degree of opening of the arms of the contact varies from one jig to another. Much of this depends on the precision with which the parts of the jig are made, with a result that the amount of opening of the contact arms cannot be controlled by the structure of the socket body alone.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an apparatus which overcomes the above noted limitations of the prior art. Another object of the invention is the provision of a socket in which the amount of opening of the arm-like contact part of the contact member can be predetermined at a certain value by means of the socket itself without depending upon the accuracy of the various parts of the jig.
A socket made in accordance with the invention comprises a main socket body for removably receiving an electronic part in which the terminals of the electronic part are arranged according to a selected pattern. A plurality of contact members are arranged in the main socket body in conformity with the terminal pattern of the electronic part. Each contact member has a pair of contact arms, capable of elastically opening and closing to effect compressive electrical engagement with a respective connective terminal of the electronic part. A contac
Baumann Russell E.
Bradley P. Austin
Gushi Ross
Telecky , Jr. Frederick J.
Texas Instruments Incorporated
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