U.S. patent application number 09/826499 was filed with the patent office on 2001-08-09 for integrated circuit socket with contact pad.
This patent application is currently assigned to Urex Precision, Inc.. Invention is credited to Ho, Han-Shin, Kuo, Chien-Shuan, Lai, Wei-Hai, Shieh, Deng-Tswen, Wang, Ming-Hsien, Whung, Chin-Ting.
Application Number | 20010012707 09/826499 |
Document ID | / |
Family ID | 23805074 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010012707 |
Kind Code |
A1 |
Ho, Han-Shin ; et
al. |
August 9, 2001 |
Integrated circuit socket with contact pad
Abstract
An integrated circuit socket having a contact pad is disclosed.
The integrated circuit socket comprises: (1) a base unit, it
further consists of a base, contact pins and an elastomer. The
contact pins will provide the electrical contact of the other
elements, the elastomer provides the compactness of the assembly.
(2) an interposer, there are a flexible film, a stiffener and a
stop layer wherein the contact pad of the flexible film may contact
with the solder ball of IC device to buffer the pressure formed by
a tight contact when IC device is moving downward. The pressure
will be dispersed with the flexible film such that the testing
signals are transmitted. (3) an adapter unit, the unit is capable
of positioning the integrated circuit device and includes a
depressor to suppress or release the integrated circuit. (4) a
cover unit, the cover unit is located over the base, the interposer
and the adapter unit, and includes a cover and a spring such that
the cover is coupled to the depressor of the adapter unit and is
capable of vertically moving up and down.
Inventors: |
Ho, Han-Shin; (Hsinchu
Hsien, TW) ; Lai, Wei-Hai; (Hsinchu, TW) ;
Kuo, Chien-Shuan; (Hsinchu, TW) ; Shieh,
Deng-Tswen; (Kaohsiung, TW) ; Wang, Ming-Hsien;
(Taipei, TW) ; Whung, Chin-Ting; (Hsinchu Hsien,
TW) |
Correspondence
Address: |
POWELL, GOLDSTEIN, FRAZER & MURPHY LLP
P.O. BOX 97223
WASHINGTON
DC
20090-7223
US
|
Assignee: |
Urex Precision, Inc.
|
Family ID: |
23805074 |
Appl. No.: |
09/826499 |
Filed: |
April 5, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09826499 |
Apr 5, 2001 |
|
|
|
09454550 |
Dec 7, 1999 |
|
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Current U.S.
Class: |
439/71 ; 439/331;
439/525; 439/526; 439/67; 439/73 |
Current CPC
Class: |
G01R 1/0483 20130101;
H01R 12/714 20130101; H01R 2201/20 20130101; H05K 3/325
20130101 |
Class at
Publication: |
439/71 ; 439/67;
439/73; 439/525; 439/526; 439/331 |
International
Class: |
H05K 001/00; H01R
012/00; H01R 013/62 |
Claims
What is claimed is:
1. An integrated circuit (IC) socket, said socket comprises: a base
unit, said base unit includes a base, a contact pin and an
elastomer, said elastomer is located at the upper portion of said
base and said contact pin is fastened inside a recessed portion of
said base; an interposer, said interposer includes a flexible film,
a stop layer, and a stiffener, wherein said flexible film has a
contact pad to connect a solder ball of a IC device to said contact
pad, said stop layer located on said flexible film is used to
buffer a pressure formed by a tight contact when said IC device is
moving downward, and said stiffener located on said stop layer is
used to support said flexible film and said stop layer; an adapter
unit, said adapter unit is placed on said base unit and said
interposer and includes an adapter and a depressor, wherein said
adapter unit provides the positioning function of said IC device,
said depressor can suppress or release said IC device; and a cover
unit, said cover unit is located over said base, said interposer
and said adapter unit, and includes a cover and a spring, wherein
said cover is coupled to said depressor of said adapter unit and is
capable of moving up and down vertically.
2. The IC socket of claim 1, wherein said flexible film has
compliance such that said solder ball is guided automatically into
said contact pad of said flexible film.
3. The IC socket of claim 1, wherein said stop layer is the one
selected from a group consisting of a larger distribution region, a
smaller distribution region and a line distribution region.
4. The IC socket claim 3, wherein said larger distribution region
comprises an exposure of contact region.
5. The IC socket of claim 3, wherein said smaller distribution
region comprises an exposure of contact pad region.
6. The IC socket of claim 3, wherein said line distribution region
comprises an exposure of contact pad region at a line.
7. The IC socket of claim 1, wherein said contact pad is one type
selected from a group consisting of a ring type, a bump type and a
ring-bump type.
8. The IC socket of claim 7, wherein said ring type comprises a
through hole having a contact arc to form line contact.
9. The IC socket of claim 7, wherein said bump type comprises a tip
or a plurality of tips to penetrate the oxidation layer on the
surface of said IC device.
10. The IC socket of claim 7, wherein said ring-bump type comprises
a through hole having a contact arc.
11. The IC socket of claim 7, wherein said ring-bump type comprises
a tip or a plurality of tips to penetrate the oxidation layer on
the surface of said IC device.
12. The IC socket of claim 1, wherein said contact pad of said
flexible film is electrically connected with said solder ball of
said IC device directly.
Description
[0001] This application is a continuation-in-part of Ser. No.
09/454,550 filed Dec. 7, 1999.
FIELD OF THE INVENTION
[0002] The present invention relates to an integrated circuit
socket, and more particularly, to an integrated circuit socket with
a contact pad.
BACKGROUND OF THE INVENTION
[0003] With the rapid development of semiconductor industry these
years, when the density of integrated circuits (ICs) has been
becoming higher gradually, the gate length is decreased to
sub-micron range, even deep sub-micron. Nevertheless, the lifetime
of products has become much shorter. Since the variable requirement
with IC devices also increased, there are products with different
functions, sizes, and pin assignment.
[0004] In the processing steps of semiconductor devices, there are
many test procedures after IC devices are accomplished to ensure
the functionality and quality of the IC devices. For example, these
test procedures of an IC chip may include the examination of lead
frame, the power consumption, the basic logic analysis, the output
impedance measurement and the "Burn-in" test. The basic hardware
configuration of these test procedures is to use a socket or a
connector to locate the IC chip.
[0005] The Conventional connector of the IC chip, such as logic
circuits for central processing unit (CPU) or memory unit, is all
with specific usage and pin assignment. As the IC chip is in a
"burn-in test", conventional sockets are designed for a specific
kind of an IC chip. A clamping structure of socket is used to fix
the IC chip and conduct it for testing. Since the conventional
clamping structure is designed for pin contact, the way may get the
surface of the solder balls pierced, which is harmful to solder
balls and results in the damage of the solder balls. Testing
current circulating among the contact interface is blocked with
ease, causing the high contact resistance values so that the whole
electrical contact of the IC chip is obviously degraded.
[0006] Therefore, the contact interface must be kept in a good
electrical contact to form a preferred contact region between
solder balls and contact pad, making current circulate easily, that
is to say IC chip must to be exactly located in the contact pad.
However, the conventional pin contact is apparently disadvantageous
to circulation of current since the contact region is too smaller.
Further, a none damage zone (NDZ) is defined as an essential
contact region where is used to solder IC chip with the printed
circuit board (PCB). The good condition of the NDZ, including
geometric shape and electrical property, need to be held all the
time during IC testing so as to contribute to exactly solder NDZ
with the PCB after the IC chip is completely tested.
SUMMARY OF THE INVENTION
[0007] In view of the foregoing about conventional integrated
circuit (IC) socket, it has been encountered with various problems
all the time. The primary object of the present invention is to
provide an integrated circuit socket with a contact pad.
[0008] According to the main object, the present invention offers
an integrated circuit socket with a contact pad, wherein the
contact pad comprises:
[0009] (1) A base unit: it further includes a base, a contact pin
and an elastomer wherein the elastomer is located at the upper
portion of the base and the contact pin is fastened inside a
recessed portion of the base.
[0010] (2) An interposer: it further includes contact pads,
conductive wires, pads, a flexible film, a stiffener, a stop layer
and positioning holes. These positioning holes are used to match up
with the base unit in order to assemble exactly the IC socket by
dowel. In operation, the contact pads, located on the center of the
interposer, are contact with the solder balls of the IC device.
Electrical signals are transmitted from the IC device to the
contact pads, and then pass through the coupling conductive wire to
the pads, finally come over the contact portion of the contact pin
to the circuits of the PCB.
[0011] (3) A adapter unit: the adapter unit, including an adapter
and a depressor, is placed on the base unit and the interposer and
the adapter unit provides the positioning function of IC device and
the depressor can suppress or release the IC device.
[0012] (4) A cover unit: the cover unit is located over the base,
the interposer and the adapter unit, and includes a cover and a
spring such that the cover is coupled to the depressor of the
adapter unit and is capable of vertically moving up and down.
[0013] According to the present invention, the contact type between
the solder ball and the contact pad provides a preferred protection
and also doesn't tend to contribute to deformation resulting in
ineffectively electrical contact. Further, the electrical contact
is better since the contact type between the solder ball and the
contact pad is line or surface contact in partial region.
Furthermore, a NDZ can be readily kept in a good condition so as to
form a preferred contact interface and the deformation of the
solder ball is smaller than that of the conventional pin
contact.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated as the same
becomes better understood by reference to the following detailed
description, when taken in conjunction with the accompanying
drawings, wherein:
[0015] FIG. 1 is an exploded perspective drawing of a IC socket
according to the present invention;
[0016] FIGS. 2A.about.2D is the three views of the IC socket
comprising the modules-assembled according to the present
invention;
[0017] FIG. 3 is a front view of the interposer according to the
present invention;
[0018] FIG. 4 illustrates the interposer contact with the IC device
according to the present invention;
[0019] FIGS. 5A.about.5C illustrates the preferred types of the
stop layers according to the present invention; and
[0020] FIGS. 6A.about.6C illustrates the preferred contact types
between a solder ball and a contact pad according to the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring now to FIG. 1, this figure shows an exploded
perspective drawing of an IC socket. The IC socket module in this
figure is the base unit 100, the interposer 200, the adapter unit
300 and the cover unit 400. The base unit 100 is a housing with
contact pins welded on a printing circuit board (not shown in the
figure). Next, the interposer 200 is a material with contact pads
and conductive wires connected electrically thereon. Then, the
adapter unit 300 is a device with clasps to fasten the whole IC
socket. Finally, the cover unit 400 is used for suppressing or
releasing the IC device.
[0022] Referring to FIGS. 2A.about.2D, the three different views of
the IC socket comprising the modules-assembled are shown. The FIG.
2A is a vertical view of the IC socket, and the FIG. 2D is a
cross-sectional view at line AA in FIG. 2A, the FIGS. 2B and 2C are
cross-sectional views at line BB in FIG. 2A. For better
understanding of the drawings, wherein the interposer 200 is the
significant characteristic of the present invention, the primary
four devices of the IC socket is described as follows:
[0023] (1) The base unit 100: In FIG. 2D, the base unit 100
comprises a base 110, contact pins (150, 160) and an elastomer 190.
There are recessed regions in the base 110 to support the contact
pins (150, 160) and the elastomer 190. The elastomer 190 is located
on the upper portion of the base 110 with a good compressibility
and elasticity. Due to the elastic effect of the elastomer 190, the
IC device under test and the interposer 200 will be closely
connected to the base unit 100 the whole IC socket is assembled,
therefore enhancing the electrical contact between different
elements.
[0024] Still referring to FIG. 2D, the interposer 200 is rigidly
close to the base 110 having the elastomer 190 in-between. The
fastened contact pin 150 in the base 110 is used to electrically
connect the upper interposer 200 and the underneath printed circuit
board (not shown in the figure). The stationary portion 154 of the
contact pin 150 is located in the recession of the base 110 as
shown in the figure. The central part of the contact pin 150 is a U
shape cantilever 156 and a contact portion 158. The contact pin 156
provides a good flexibility due to the specific configuration of
the U shape cantilever 156. Therefore, when the interposer 200 and
the base unit 100 are assembled together, the contact portion 158
of the contact pin is connected to the interposer 200 and keeps a
good electrical contact owing to the U shape cantilever 156.
[0025] (2) The interposer 200: Referring to FIG. 3, the figure is a
front view of the interposer 200. The interposer 200 includes
contact pads 210, conductive wires 220, pads 230, a flexible film
260, a stiffener 250, a stop layer 270 and positioning holes 240.
These positioning holes 240 are used to match up with the base unit
100 in order to assemble exactly the IC socket by dowel. In
operation, the contact pads 210, located on the center of the
interposer 200, are contact with solder balls of the IC chip.
Electrical signals are transmitted from the IC chip to the contact
pads 210, and then pass through the coupling conductive wires 220
to the pads 230, finally come over the contact portion of the
contact pin (150, 156) to the circuits of the PCB.
[0026] Referring to FIG. 4, the figure shows the cross-sectional
view of the interposer contact with the IC device. The interposer
200 comprises a flexible film 260, a higher glass transition
temperature T.sub.g, and an excellent mechanical property, which is
well suited to testing under the high temperature and high
frequency. The stiffener 250, made of a temperature-resistant
material, is used to uphold the flexible film 260. The contact pads
210 of the flexible film 260 are used to receive the solder balls
510 of the IC device 500. The IC device 500 would be roughly put
over the contact pads 210 of the flexible film 260 and precisely
guided by a recession of the contact pad 210.
[0027] Further, the contact pads 210 on the flexible film 260 are
electrically connected to the pads 230 via conductive wires 220,
and the pads 230 are next electrically connected to the contact
portions 158 of the contact pin 150 as shown in FIG. 3. The
compliance is an another significant feature of the flexible film
260, which is defined as a characteristic that the solder balls 510
are guided automatically into the contact pads 210 of the flexible
film 260, while the IC device 500 is positioning on the flexible
film 260. Since each of solder ball 510 is not uniform in size, the
contact region, composed of a plurality of contact interfaces, may
result in deflection phenomenon on contact region. Such situation
will contribute to the variation about electrical property due to
the distinct contact pressure. As a result, the advantage of the
compliance for the flexible film 260 is properly adaptive to the
different type of the PCB such that the solder balls 510 can be
guided automatically by the flexible film 260 to make the contact
pressure uniform.
[0028] The stop layer 270 is located between the flexible film 260
and the stiffener 250, and buffers the pressure formed by a tight
contact when IC device 500 is moving downward. The contact pressure
between the solder balls 510 and contact pads 210 may vary from
tight to loose in a certain extent. When the IC device 500 is
contacting with the stop layer 270, the contact pressure will be
dispersed due to gradually bigger contact region on the flexible
film 260 so that the deformation of the solder balls 510 is also
much smaller. In other word, the distortion of the solder balls 510
is evidently decreased. The flexible film 260 is partially covered
with the stop layer 270 to protect the exposed circuits. In other
word, the flexible film 260 can be used as an isolation layer to
separate the conductive wire 220 on the flexible film 260.
[0029] Referring to FIGS. 5A.about.5D, in the preferred embodiment
of the present invention, according to the size of the exposed
region on the stop layer 270, the stop layer 270 types comprises
three distinct types as follows:
[0030] (1) A larger distribution region: As shown in FIG. 5A, the
exposed contact region has a good compliance because the contact
region includes the partial flexible region 520.
[0031] (2) A smaller distribution region: As shown in FIG. 5B, the
exposed contact region has a good uniform pressure onto the contact
interface because the contact region merely includes a small area
530 about the adjacent contact pad.
[0032] (3) A line distribution region: As shown in FIG. 5C, the
exposed contact region has a good compliance and uniform a contact
pressure because the contact region includes the partial flexible
film 260 region in a line area 540 around the contact pads.
[0033] Referring to FIGS. 6A.about.6C, in the preferred embodiment
of the present invention, the types of contact pads 210 on the
flexible film 260 comprise three distinct types as follows:
[0034] (1) A ring type 620 of contact pad: As shown in FIG. 6A, a
ring type 620 of contact pad having a contact arc 622 offers a
better electrical contact than that of the conventional pin
contact. Further, the central through hole reserved for the contact
pad 210 can effectively prevent the NDZ 626 of the solder balls 510
from damage.
[0035] (2) A bump type 640 of contact pad: As shown in FIG. 6B, a
bump type 640 of contact pad 210 has one or a plurality of tips
642, such as three tips preferably. And thus the thin oxide layer
on the solder ball 510 can be penetrate with the tips 642 to make
current smoothly circulate through the contact region. Moreover,
another benefit is the bump type 640 of contact pad 210 can provide
a better compensation of the latitude difference between the solder
balls 510 and the contact pads 210.
[0036] (3) A ring-bump type 660 of the contact pad: As shown in
FIG. 6C, a ring-bump type of the contact pad has a contact arc 662
and one or a plurality of tips 664, such as three tips preferably,
used to penetrate the thin oxide layer on the surface of the solder
ball 510. Therefore, the electrical contact and the latitude
between the solder balls 510 and the contact pad 210 can be greatly
improved. Further, the central through hole reserved for the
contact pad 210 can effectively inhibit the NDZ 668 of the solder
ball 510 from damage.
[0037] All types of contact pad 210 which are mentioned above may
dispose on the flexible film 260 or thin film to provide the
benefit of the auto-guiding and help the solder balls 510 position
rapidly. Any types of contact pad 210, the ring type 620 of contact
pad, the bump type 640 of contact pad or the ring-bump type 660 of
contact pad, will provide an stable contact effect and
automatically guide the solder balls 510 of IC device 500.
[0038] (3) The adapter unit 300: Returning to FIGS. 2A to 2D, the
element between the interposer 200 and the cover unit 400 is an
adapter unit 300. The adapter unit 300 comprises an adapter base
330 (as shown in FIG. 2C), a depressor 310, and a shaft 320 (as
shown in FIG. 2B), wherein the adapter base 330 is used to conduct
the IC device 500 located in a test area easily and then
electrically contact with the interposer 200.
[0039] (4) The cover unit 400: The cover unit comprises a cover and
springs 410. As described above, the cover unit 500 can move up and
down vertically and drive the coupling depressor 310 to press or
release the IC device 500. Further referring to FIG. 2C, an upper
and a lower position of the cover unit 400 are also shown in this
figure. The springs 410 inside the four corner of the cover unit
400 are used to provide the flexibility and force to move the cover
unit 400 up and down.
[0040] In summary, a IC socket with a contact pad is described in
the present invention wherein the type of the contact pad provide a
good protection for the solder balls 510 and don't form the
deformation of the solder balls 510 to improve the electrical
contact. Additionally, the contact type between the solder balls
510 and the contact pad is line contact or partial region contact.
Furthermore, the completeness of the NDZ region is remains all the
time and forms a better contact interface. Moreover, the
deformation of the solder balls 510 is smaller than that of the pin
contact with convention.
[0041] As is understood by a person skilled in the art, the
foregoing preferred embodiments of the present invention are
illustrated of the present invention rather than limiting of the
present invention. It is intended to cover various modifications
and similar arrangements included within the spirit and scope of
the appended claims, the scope of which should be accorded the
broadest interpretation so as to encompass all such modifications
and similar structure.
* * * * *