Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
2002-07-23
2004-02-17
Gilman, Alexander (Department: 2833)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
C439S857000, C439S856000, C439S083000
Reexamination Certificate
active
06692265
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to an electrical connection device. Especially, the present invention relates to the structure improvement of the electrical connection device soldered on a main board by solder balls, wherein the device can be provided for inserting and placing an IC package.
(b) Description of the Prior Art
For long time, there are two ways that placing the Integrated Circuit (IC) Package on the Circuit Board (or Main Board). In one of the two ways, the IC is soldered fixedly on the main board and can not be removed. Another way the IC is replaceable. The replaceable electrical connecting device and the IC combining device are usually suitable in a IC package that needs upgrade sometimes or in a IC package with high price. In the case that one of the IC package broken and needs to be replaced, other packages can be kept. The best example is the socket and the circuit board connecting device that used for a Central Processing Unit (CPU).
Please refer to FIG.
1
and
FIG. 2
, which showing the typical replaceable IC package and the composition device of the electrical connecting device and the main board in the market. Conventionally, in order to maintain the excellent electrical connection and the replaceable-ness, the pins
111
are placed on the IC package
11
and the socket
13
with a plurality of pin holes
131
is set on the circuit board
12
to connect the IC package
11
. In prior art, there are two package methods to pack an IC package, namely Lead Frame and Ball Grid Array (BGA). In recent years, the Flip Chip BGA Packaging is often used for an IC package that needs high efficiency and high number of pins.
FIG. 1
is showing its basic devices, which comprising the IC chip
112
being placed on one side of the substrate
113
by the Flip Chip method, several solder balls
114
being placed on the another side of the substrate
113
that connected electrically to the chip
112
thru the circuit layout of the substrate
113
, and the heat sink
115
is attached on the other side of the chip
112
that will not operate. Since the pin
111
is not hard and still enough, it is easy to be distorted and damaged during replacement. So in practice, a plurality of the pins
111
will be molded and fixed on a interposer
116
before it soldered on the solder ball
114
.
Traditionally, the plugged-in electrical connection device
13
is composed of the following elements in order to maintain the replaceable feature. The elements include of the main board
12
on which there are the sockets
132
with a plurality of the pin hole
131
, a slide
133
that can be moved linearly on top of the socket
132
and a pulling long stick
134
placed on the side of the socket
132
to drive the slide
133
to move slightly. There is electrical conducting holder
137
placed in each pin hole
131
on the socket
132
. And the solder pad
135
is formed on the bottom part of the pin hole
131
. The pin hole
131
is extended from the bottom part of the electrical conducting holder
137
to form the pins
1371
in order to provide several Plated Through Holes (PTH)
121
on the main board
12
to plug in. The electrical conducting layer
122
in the PTH
121
on the main board
12
provides the function of the electrical connection with the pins
1371
. The position of the PTH
121
and the position of the upper contact pad
1221
on the upper surface of the main board
12
is defined by the SMD (Solder Mask Defined) or NSMD (None Solder Mask Defined). The pins
1371
and the electrical connection device
13
are soldered firmly on the main board
12
by using the solder
123
and the solder
125
. Corresponding to the positions of the pin holes
131
on the slide
133
exist several bigger holes. Pulling down the pulling stick
134
and rotating it around the stick
136
until the pulling stick
134
being parallel with the socket
132
will make the slide
133
move slightly and hold the pins
111
of the IC device
11
tightly in the pin holes
131
. When pulling out the IC device
11
, the pulling stick
134
has to be moved until it making a 90 degree angle with the socket
132
to loose the pins
111
from the IC device
11
by the way.
Please refer to FIG.
3
and
FIG. 4
, which are showing another composition of the replaceable IC device and the electrical connection device and the main board. As shown, the structure of the IC device
11
in prior art is similar to the structure of the electrical connection device
13
a
in FIG.
1
. The major difference is that the bottom part of the socket of the electrical connection device
13
a
in
FIG. 3
is ball structure instead of pin structure. And the lower part of the electrically conducting holder
137
a
in the electrical connection device
13
a
is bent 90 degree to be the solder pad
139
which combines the solder ball
138
. And instead of the PTH, the solder pad
126
is placed on the main board
12
a
. The solder ball
138
will be soldered firmly between the two solder pads
139
and
126
stably by performing the solder reflow on the solder ball
138
in the electrical connection device
13
a
and the solder pad
126
on the main board
12
a
. The disadvantages in prior art are that the solder pad
139
on the bottom part of the electrically conducting holder
137
a
in the electrical connection device
13
a
and the solder pad
126
on the main board
12
a
are flatly planar structures. So, the solder ball
138
and the solder pad
139
and
126
are combined plainly. The contact area is limited, the electrical characteristic is bad and the intensity of the structure of the combination is weaker. The disadvantages lead the rising of the defects of the products and sometimes the department of the solder ball
138
. Also, the overflow of the solder ball
138
will lead the circuit shortage and the electrical instability. In the same time the disadvantage also includes the bad co-planarity between the electrical connection device
13
a
and the main board
12
a.
SUMMARY OF THE INVENTION
The primary aspect of the present invention is to provide an electrical connection device. By special design of geometry structure, the present invention will lead the strong intensity, the electrical characteristics and the co-planarity of the product, and the yield of the product after the solder reflow of the solder pad on the bottom part of the electrically conducting holder and the solder ball.
Another aspect of the present invention is to provide an electrical connection device which having a contact ring optionally on the bottom parts of the pin holes in the sockets to enlarge the contact area between the solder ball, the sockets and the electrically conducting holders.
The third aspect of the present invention is to provide an electrical connection device which having a contact ring optionally on the bottom parts of the pin holes in the sockets, and at least a portion of the contact ring is with difference in height with the solder pad on the bottom part of the electrically conducting holder, with this difference of horizontal altitude between the geometric structure, the present invention will enlarge the contact area between the solder ball, the sockets and the electrical conducting holders,
The fourth aspect of the present invention is to provide an electrical connection device. With increasing a additional convex part on the bottom surface of the pin holes in the sockets to contact the periphery of the solder pad on the bottom part of the electrically conducting holder, the present invention will avoid the solder material in siphon phenomenon between the electrically conducting holder and the pin holes in the solder reflow process. And because the additional convex part placed against the solder ball, which will avoid the electrical conducting holder from being released or removed that caused by the pushing force of the solder ball. In one of the embodiment of the electrical conducting device of the present invention, we increase the contact area of the solder ball
Ho Kwun-Yao
Kung Moriss
Gilman Alexander
Via Technologies Inc.
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