Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
2000-10-23
2001-09-11
Patel, Tulsidas (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
C439S071000, C439S331000
Reexamination Certificate
active
06287127
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an electrical socket for removably loading an electric part such as an IC (integrated circuit) having electrical terminals on its lower surface and electrically connecting each terminal to external equipment and more particularly to such a socket especially adapted for use with semiconductor packages of the BGA (Ball Grid Array) type.
BACKGROUND OF THE INVENTION
Ordinarily, plastic encapsulated IC packages are subjected to electric property tests and a reliability test called a burn-in test prior to shipment in order to distinguish between good and defective products. In an electrical property test, input and output characteristics of the IC chip, pulse properties, noise leeway, and the like, are tested. Those IC packages that pass the electric property test are then subjected to a burn-in test in which they are arranged in an oven and caused to function for a certain period of time at a selected high temperature, for example, 125° C., and under a source voltage which is approximately 20 per cent higher than the rated value. IC packages that fail the burn-in test are discarded as defective products and only those IC packages that continue functioning properly are shipped out as good products.
BGA packages having spherical solder balls arranged on the lower side of the packages in a selected matrix or zigzag fashion are in wide use. This type of package is capable of having an increased terminal pitch with a small outer dimension and is more resistant to damage caused by contact with other parts.
FIGS. 6
a
and
6
b
show a typical prior art socket used for burn-in tests of IC's such as BGA packages. Socket
101
comprises a plastic (in plan view) rectangular base
102
on which is mounted a horizontally movable slider
103
which receives thereon a BGA package. A frame shaped cover defining an opening
104
a
, also made of plastic, is received on top of base
102
and is vertically movable relative to the base. The cover is biased in a direction away from the base by means of compression coil springs
105
. A through hole corresponding to each solder ball
100
a
of the BGA package is formed in slider
103
and base
102
. A contact member
106
for electrical connection with a respective solder ball
100
a
of the BGA package is arranged to run through each of the through holes of slider
103
and base
102
. Each contact member
106
comprises an elongated metallic member having a pair of arms
106
a
and
106
b
provided at one end thereof. Each contact member
106
is fixed in a vertical attitude on base
102
, with arms
106
a
and
106
b
facing upwardly. Each contact member has a protruding part such as a tab (not shown in the drawing), on one of side by side arms
106
a
,
106
b
. Arms
106
a
,
106
b
open relative to one another as the tab engages with a partition wall (not shown in the drawing) of slider
103
. A sliding mechanism for moving slider
103
in parallel with the bottom of base
102
comprises a pair of generally L-shaped lever member
108
rotatably connected at opposite ends of a shaft
107
. Shaft
107
is received in a slot formed at the right side of slider
103
as seen in the drawings. A short arm
108
a
of each lever member
108
is rotatably connected to a shaft
109
mounted in base
102
thereof at one side (the right-hand side shown in the drawing), installed so that it extends in parallel with shaft
107
. A respective lever member
111
is rotatably connected at both ends of a shaft
110
mounted on the opposite side of base
102
and extending in parallel with shafts
107
,
109
and the end portion of each lever member
108
is slidably connected in a longitudinally extending slot formed in the middle part of lever members
111
by means of pins
112
. The distal tip
11
l
a
of lever member
111
engages a protruding part
104
b
of the top wall of cover
104
. Horizontally disposed compression coil springs
113
are placed between base
102
and slider
103
in the vicinity of shaft
110
for biasing the slider in the direction shown by the head of arrow X in
FIG. 6
b.
In a socket
101
constructed as described above, if cover
104
is pressed down from the position shown in
FIG. 6
a
to the position shown in
FIG. 6
b
, lever members
108
and
111
rotate toward base
102
and shaft
107
moves slider
103
in conformity with the movement of lever member
108
, thereby shifting it in the opposite direction from the one indicated by arrow head X. As a result of this, one of the arms, for example, arm
106
a
of each contact member
106
, engages the partition wall of slider
103
and is thereby opened. If, in this state, BGA package
100
is inserted into adaptor
103
c
of slider
103
, each solder ball
100
a
of BGA package
100
enters the gap between the open arms
106
a
and
106
b
of a respective contact member
106
. When the downward force on cover
104
is removed, lever members
108
and
111
rise and slider
103
moves in the direction of the head of arrow X by means of the force exerted by compression coil springs
113
, closing arms
106
a
and
106
b
of each contact member
106
with each solder ball
100
a
of BGA package
100
held by arms
106
a
and
106
b
of a respective contact member
106
. As a result of this, each solder ball
100
a
of BGA package
100
can be electrically connected to a respective contact member
106
.
In the case of a prior art socket as described above, however, the linkage mechanism made by lever members
108
,
111
and associated shafts used for moving slider
103
requires an increased number and complexity of parts along with an increase in the number of steps and time for assembling the product.
Further, such linkage mechanisms increase the size and weight of the socket itself.
SUMMARY OF THE INVENTION
An object of the present invention is the provision of an electrical socket of light weight and small size in which the number of parts involved is small and the construction is simple. Another object of the invention is the provision of a socket which overcomes the limitations of the prior art noted above and having fewer parts, of a simple structure, light weight and small size.
An electrical socket made in accordance with the invention comprises a base for removably loading an electric part such as a plastic encapsulated IC package in which the conductive terminals of the electric part are arranged according to a selected pattern, a plurality of contact members arranged in the base in accordance with the arrangement pattern of the conductive terminals of the electric part with each contact member having a pair of contact arms capable of elastically opening and closing to sandwich a respective conductive terminal of the electric part. A contact actuating member is provided having engagement parts for engaging with at least one arm of each pair of contact arms of each contact member to open or close the contact arms. The contact actuating member moves in the opening and closing direction of the contact arms by receiving an external force on a force receiving surface in a direction which crosses, approximately at a right angle, the opening and closing direction of the contact arms. The force receiving surface includes a portion inclined by a selected angle relative to the direction of the external force. According to a feature of the invention, a motion transfer portion engages the force receiving surface of the contact actuating member. The movement of the motion transfer portion is in a direction which crosses, approximately at a right angle, the opening and closing direction of the contact arms. According to the first preferred embodiment, the motion transfer portion extends downwardly from a cover positioned over the socket body. According to a feature of an alternate embodiment, the motion transfer portion extends downwardly from a head movable toward and away from the socket base, the head provided with a holding part which is capable of removably holding the electric part. According to another feature of the alternate
Ezura Toyokazu
Hibino Yasushi
Ikeya Kiyokazu
Ochiai Yasuhiro
Takahashi Hideyuki
Baumann Russell E.
Patel Tulsidas
Telecky , Jr. Frederick J.
Texas Instruments Incorporated
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