U.S. patent application number 09/159819 was filed with the patent office on 2002-03-28 for socket, circuit board, and sub-circuit board for semiconductor integrated circuit device.
Invention is credited to CHAE, HYO GEUN, CHOI, SANG YOUNG, MIN, BYOUNG JUN.
Application Number | 20020037672 09/159819 |
Document ID | / |
Family ID | 19532436 |
Filed Date | 2002-03-28 |
United States Patent
Application |
20020037672 |
Kind Code |
A1 |
MIN, BYOUNG JUN ; et
al. |
March 28, 2002 |
SOCKET, CIRCUIT BOARD, AND SUB-CIRCUIT BOARD FOR SEMICONDUCTOR
INTEGRATED CIRCUIT DEVICE
Abstract
An embodiment of the present invention provides a circuit board
and a socket having mechanical connector for easily connecting and
disconnecting a semiconductor integrated circuit device to and from
the circuit board. Another embodiment further includes a
sub-circuit board for electrically connecting the socket to the
circuit board. The socket includes a socket body and a number of
socket leads. The socket leads are shaped to compress elastically
when inserted in a hole and thereby make contact between the socket
leads and inner walls of the holes of the circuit board. The
sub-circuit board has connection leads, which make contacts with
the through holes of the circuit board in the same manner as the
socket leads of the present invention.
Inventors: |
MIN, BYOUNG JUN;
(CHUNGCHEONGNAM-DO, KR) ; CHAE, HYO GEUN;
(CHUNGCHEONGNAM-DO, KR) ; CHOI, SANG YOUNG;
(CHUNGCHEONGNAM-DO, KR) |
Correspondence
Address: |
SKJERVEN MORRILL MACPHERSON LLP
25 METRO DRIVE
SUITE 700
SAN JOSE
CA
95110
US
|
Family ID: |
19532436 |
Appl. No.: |
09/159819 |
Filed: |
September 23, 1998 |
Current U.S.
Class: |
439/751 |
Current CPC
Class: |
H05K 3/308 20130101;
H01R 12/585 20130101 |
Class at
Publication: |
439/751 |
International
Class: |
H01R 011/22 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 1998 |
KR |
1998-3014 |
Claims
What is claimed is:
1. A socket for electrically connecting a semiconductor integrated
circuit device to connection portions of a circuit board, the
socket comprising: a socket body; and a plurality of socket leads,
each socket lead comprising: an inner connection portion for
contacting an external terminal of the semiconductor integrated
circuit device; and an outer connection portion, which is
integrated with the inner connection portion, for contacting an
associated connection portion of the circuit board at a hole in the
associated connection portion,wherein each outer connection portion
is shaped to compress elastically when inserted into the hole in
the associated connection portion of the circuit board and thereby
provide a frictional contact with an inner wall of the hole of the
associated connection portion of the circuit board.
2. The socket of claim 1, wherein the outer connection portions are
shaped to provide a friction contact.
3. The socket of claim 1, wherein a central portion of the outer
connection portion has greater width than that of a lower portion
and an upper portion of the outer connection portion.
4. The socket of claim 1, wherein the outer connection portion is
in a loop.
5. The socket of claim 4, wherein a lower half portion of the outer
connection portion is substantially "V" shaped.
6. The socket of claim 4, wherein an upper half portion of the
outer connection portion is substantially inverted "V" shaped.
7. The socket of claim 4, wherein the outer connection portion has
an elliptical hook shape.
8. The socket of claim 1, wherein the outer connection portion is
in an open shape.
9. The socket of claim 8, wherein the outer connection portion is
substantially .sup.2S.sup.2 shaped.
10. The socket of claim 1, wherein a width of the widest portion of
each outer connection portion is greater than a diameter of the
hole in the associated connection portion of the circuit board.
11. The socket of claim 10, wherein the width of the widest portion
of the outer connection portion is greater than the diameter of the
hole in the associated connection portion of the circuit board by
about 0.1 mm.
12. The socket of claim 1, wherein the circuit board is a test
circuit board.
13. The socket of claim 1, wherein the inner connection portions of
the socket leads electrically connect to the external terminals of
the semiconductor integrated circuit device by the mechanical
contact.
14. The socket of claim 1, wherein the external terminals of the
semiconductor integrated circuit device are outer leads of a
semiconductor device package.
15. The socket of claim 1, wherein the external terminals of the
semiconductor integrated circuit device are solder balls of a
semiconductor device package.
16. The socket of claim 1, wherein each outer connection portion
contacts the inner wall of the hole in the associated connection
portion of the circuit board at plural points.
17. A circuit board for electrically testing a semiconductor
integrated circuit device, the circuit board comprising: a
plurality of connection portions, each connection portion having a
hole: and wiring patterns which electrically connect respective
holes to a tester, wherein the circuit board is connected to a
socket, which has a plurality of socket leads, by receiving a part
of each socket lead within a hole in an associated connection
portion of the circuit board, and the part is shaped to have
elasticity, which makes the part contact an inner wall of the hole
in the associated connection portion of the circuit board.
18. The circuit board of claim 17, which is a burn-in test circuit
board.
19. The circuit board of claim 17, wherein the part of each socket
lead, which is received within the hole in the associated
connection portion of the circuit board, is shaped to provide
frictional contact.
20. The circuit board of claim 17, wherein a central portion of the
part of each socket lead, which is received within the hole in the
associated connection portion of the circuit board, has greater
width than that of a lower portion and an upper portion of the part
of the socket lead, which is received within the hole in the
associated connection portion of the circuit board.
21. The circuit board of claim 17, wherein the part of each socket
lead, which is received within the hole in the associated
connection portion of the circuit board, is in a loop.
22. The circuit board of claim 21, wherein a lower half portion of
the part of each socket lead, which is received within the hole in
the associated connection portion of the circuit board, is
substantially "V" shaped.
23. The circuit board of claim 21, wherein an upper half portion of
the part of each socket lead, which is received within the hole in
the associated connection portion of the circuit board, is
substantially inverted "V" shaped.
24. The circuit board of claim 21, wherein the part of each socket
lead, which is received within the hole in the associated
connection portion of the circuit board, has an elliptical hook
shape.
25. The circuit board of claim 17, wherein the part of each socket
lead, which is received within the hole in the associated
connection portion of the circuit board, is in an open shape.
26. The circuit board of claim 25, wherein the outer connection
portion is substantially .sup.2S.sup.2 shaped.
27. The circuit board of claim 17, wherein width of the widest
portion of the part of each socket lead, which is received within
the hole in the associated connection portion of the circuit board,
is greater than a diameter of the through hole.
28. The circuit board of claim 27, wherein the width of the widest
portion of the part of each socket lead, which is received within
the hole in the associated connection portion of the circuit board,
is greater than the diameter of the through hole by about 0.1
mm.
29. The circuit board of claim 17, wherein another part of each
socket lead is electrically connected by mechanical contact to one
of a plurality of external terminals of the semiconductor
integrated circuit device.
30. The circuit board of claim 29, wherein the external terminals
of the semiconductor integrated circuit device are outer leads of a
semiconductor device package.
31. The circuit board of claim 17, wherein the external terminals
of the semiconductor integrated circuit device are solder balls of
a semiconductor device package.
32. The circuit board of claim 17, wherein the part of each socket
lead, which is received within the hole in the associated
connection portion of the circuit board, contacts the inner wall of
the hole in the associated connection portion of the circuit board
at multiple points.
33. The circuit board of claim 17, wherein the inner wall of the
through hole is made of a conductive abrasion-resistant
material.
34. The circuit board of claim 33, wherein the conductive
abrasion-resistant material is gold(Au).
35. The circuit board of claim 17, wherein the inner wall of the
hole is made of a conductive oxidation-resistant material.
36. The circuit board of claim 35, wherein the conductive
oxidation-resistant material is gold(Au).
37. A sub-circuit board for electrically connecting a socket, on
which a semiconductor integrated circuit device is mounted, to a
circuit board, the sub-circuit board comprising: a plurality of
connection portions; wiring patterns, which electrically connect
the connection portions to a plurality of respective external
terminals of the semiconductor integrated circuit device; and a
plurality of connection leads, an end of each connection lead being
fixed to one of the connection portions and the other end of the
connection lead being connected to the circuit board. wherein an
end of each connection lead is shaped to compress elastically when
inserted into a hole in an associated connection portion of the
circuit board and thereby provide a frictional contact with an
inner wall of the hole of the associated connection portion of the
circuit board.
38. The socket of claim 37, wherein a central portion of the end of
each connection lead has a greater width than that of a lower
portion and an upper portion of the end of connection lead.
39. The socket of claim 37, wherein the end of each connection lead
is a closed loop.
40. The socket of claim 39, wherein a lower half portion of the end
of each connection lead is substantially "V" shaped.
41. The socket of claim 39, wherein an upper half portion of the
end of each connection lead is substantially inverted "V"
shaped.
42. The socket of claim 39, wherein the end of each connection lead
has an elliptical hook shape.
43. The socket of claim 37, wherein the end of each connection lead
is in an open shape.
44. The socket of claim 43, wherein the end of each connection lead
is substantially .sup.2S.sup.2 shaped.
45. The socket of claim 37, wherein a width of the widest portion
of the end of each connection lead is greater than a diameter of
the hole of the associated connection portion of the circuit
board.
46. The socket of claim 45, wherein the width of the widest portion
of the end of each connection lead is greater than the diameter of
the hole of the associated connection portion of the circuit board
by about 0.1 mm.
47. The socket of claim 37, wherein the circuit board is a test
circuit board.
48. The socket of claim 37, wherein the external terminals of the
semiconductor integrated circuit device are outer leads of a
semiconductor device package.
49. The socket of claim 37, wherein the external terminals of the
semiconductor integrated circuit device are solder balls of a
semiconductor device package.
50. The socket of claim 37, wherein the end of each connection lead
contacts the inner wall of the hole of the associated connection
portion of the circuit board at multiple points.
51. The socket of claim 37, wherein each of the connection portions
has a hole for receiving a second end of each connection lead.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a socket, a
circuit board, and a sub-circuit board for a semiconductor
integrated circuit device, and more particularly to structures and
methods for connection and disconnection of the socket, the
sub-circuit board, and the circuit board.
[0003] 2. Description of the Related Arts
[0004] Semiconductor integrated circuit (IC) devices are tested by
various methods in order to verify their reliability. These tests
include an electrical characteristics test and a burn-in test. The
electrical characteristics test determines whether the
characteristics of a semiconductor IC fall within the
specifications of the IC, and the burn-in test applies temperature,
voltage, and/or operating signals that are beyond the normal
operating levels, to a semiconductor IC to detect latent defects
which might appear at an early stage of regular use of the IC.
[0005] Generally, in testing, a semiconductor IC is placed in a
socket that is fixed on a test circuit board that transfers
electrical signals between the semiconductor IC and a tester. FIG.
1 through FIG. 3 are cross-sectional views showing three
conventional methods for connecting a semiconductor IC 20 to a
socket 70 and a test circuit board 80.
[0006] FIG. 1 shows a method for electrically connecting socket 70
and test circuit board 80. This method is mainly employed in
Burn-In Test. For connection between socket 70 and test circuit
board 80, connection leads 75 of socket 70 are inserted into
through-holes 82 of test circuit board 80, and fixed by a
soldering.
[0007] The connection method of FIG. 1 has a number of drawbacks.
In particular, due to the use of solder 66, the connection method
of FIG. 1 may cause lead poisoning of worker. In addition, when
either socket 70 or test circuit board 80 is defective, separating
socket 70 from test circuit board 80 for replacement of the
defective component is difficult. In particular, the separation
process includes heating test circuit board 80 to melt solder 66,
and the heating may damage the wiring patterns (not shown) of test
circuit board 80. Further, extended use of socket 70 and test
circuit board 80 degrades the integrity of the bond created by
solder 66, and the connection between socket 70 and test circuit
board 80 becomes weak. This weakened connection can cause invalid
test results.
[0008] The connection method of FIG. 2 between socket 70 and a test
circuit board 100 is mainly employed in test handlers for
electrical characteristics test. In this method, a receptacle 87
serves as an intermediate connection medium between socket 70 and
test circuit board 100. Receptacle 87 is inserted into through hole
102 in test circuit board 100 and fixed by soldering. Then,
connection leads 75 of socket 70 are inserted into respective
receptacles 87. Separation of socket 70 from test circuit board is
relatively easy because connection leads 75 make only temporary
contacts with receptacles 87. However, the method in FIG. 2 has a
number of disadvantages. First, to insert connection leads 75 into
receptacles 85, external forces must be applied. Second, when
connection leads 75 are fine- pitched, the method in FIG. 2 has a
higher probability of short circuits and/or current leakage between
neighboring through holes 102 than the method in FIG. 1 because the
diameter of the through holes 102 is greater than that of through
holes 82. In particular, each hole 102 must be wide enough to
contain a receptacle 87, and thereby the distance between
neighboring through holes 102 is relatively small. Third, adding
and installing receptacles 87 increase the cost of IC tests.
[0009] To avoid the short circuits between neighboring through
holes 102 in FIG. 2, a sub-circuit board 90 can be interposed
between a socket 50 and test circuit board 100, as shown in FIG. 3.
Sub-circuit board 90 has socket 50 thereon, and wiring patterns in
sub- circuit board 90 electrically connect the connection leads
(not shown) of socket 50 to respective through holes 92 of
sub-circuit board 90. Connection pins 95 and receptacles 87 are
respectively fixed to through holes 92 and through holes 102 by
soldering. Then, connection pins 92 of sub-circuit board 90 are
inserted into respective receptacles 87. However, even though
sub-circuit board 90 can reduce or eliminate the short circuit
problem, the connection method still has high test cost due to the
additional components such as receptacles 87.
SUMMARY OF THE INVENTION
[0010] An embodiment of the present invention provides a socket and
a circuit board, with or without a sub-circuit board for
semiconductor integrated circuit device. The structure of each
component in this invention provides convenient connection and
disconnection of the socket or the sub-circuit board to and from
the circuit board and low test cost by eliminating the use of
solder and receptacles in the circuit board.
[0011] In accordance with an aspect of the present invention, the
socket has distinctively shaped socket leads that are easily
inserted into the through holes of circuit board. In addition,
shape-induced elasticity of the socket leads provides a solid
contact between the socket leads and the inner wall of the through
holes.
[0012] The circuit board includes through holes where the socket
leads are inserted, and the inner wall of the through holes are
plated with conductive abrasion-resistant materials. Respective
through holes are connected to a tester by wirings of the circuit
board.
[0013] The sub-circuit board provides a connection between a
socket, especially for fine-pitch semiconductor IC packages, and a
circuit board. The sub-circuit board comprises through holes,
wiring patterns which electrically connect the socket to the
through holes, and connection leads. An end of each connection lead
is fixed to the through holes, and the other end of the connection
lead has a distinctive shape in the same manner as in the socket
leads according to the present invention.
[0014] Moreover, the elasticity given to the socket leads and the
connection leads of sub-circuit board extends the life of the
socket and the sub-circuit board, since the socket leads and the
connection pins recover their shape as soon as they are pulled out
from the through holes of the circuit board.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] These and various other features and advantages of the
present invention will be readily understood with reference to the
following detailed description taken in conjunction with the
accompanying drawings, wherein like reference numerals designate
like structural elements, and, in which:
[0016] FIG. 1 is a cross-sectional view showing a conventional
connection method between a socket and a circuit board for testing
a semiconductor integrated circuit device;
[0017] FIG. 2 is a cross-sectional view showing another
conventional connection method between the socket and the circuit
board for testing the semiconductor integrated circuit device;
[0018] FIG. 3 is a cross-sectional view showing still another
conventional connection method between the socket and the circuit
board for testing the semiconductor integrated circuit device;
[0019] FIG. 4 is a perspective view showing an embodiment of a
socket for testing a semiconductor integrated circuit device
according to the present invention;
[0020] FIG. 5 is a cross-sectional view showing a connection method
between the socket of FIG. 4 and a circuit board;
[0021] FIG. 6 is an enlarged view showing an outer connection
portion of the socket lead of FIG. 4;
[0022] FIG. 7A is a schematic cross-sectional view showing the
outer connection portion of the socket lead of FIG. 4 before
insertion to the circuit board;
[0023] FIG. 7B is a schematic cross-sectional view showing the
outer connection portion of the socket lead of FIG. 4 after
insertion to the circuit board;
[0024] FIG. 8 is a cross-sectional view showing another embodiment
of the outer connection portion of a socket lead according to the
present invention; and
[0025] FIG. 9 is a cross-sectional view showing a connection method
between a socket and a circuit board using a sub-circuit board
according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Embodiments of the present invention will be described below
with reference to the accompanying drawings.
[0027] FIG. 4 is a perspective view showing an embodiment of a
socket for testing a semiconductor integrated circuit device
according to the present invention, and FIG. 5 is a cross-sectional
view showing a connection between the socket of FIG. 4 and a
circuit board. FIG. 6 is an enlarged view showing an outer
connection portion of the socket lead of FIG. 4. This embodiment
shows socket 10 and circuit board 30 for a burn-in test of a
semiconductor integrated circuit device 20 in an SOP (Small Outline
Package).
[0028] As shown in FIGS. 4 and 5, socket 10 comprises a socket body
11 and socket leads 15. Socket body 11 includes an upper body 12
and a lower body 13, and socket leads 15, which are integrated with
lower body 13, includes an inner connection portion 15a, an elastic
portion 15b and an outer connection portion 15c. In testing,
semiconductor integrated circuit device 20 is placed on lower body
13 so that outer leads 22 of semiconductor integrated circuit
device 20 contact respective inner connection portions 15a of
socket lead 15. Upper body 12, which sits on lower body 13, has a
cavity for semiconductor integrated circuit device 20 and is
aligned with lower body 13 by guide bars 19. Upper body 12 holds
semiconductor integrated circuit device 20 and secures the contact
between outer leads 22 of semiconductor integrated circuit device
20 and respective inner connection portions 15a of socket lead 15.
In particular, upper body 12 vertically moves up and down along
guide bars 19 and applies pressure to elastic portions 15b of
socket leads 15 so that inner connection portions 15a securely
contact outer leads 22.
[0029] With reference to FIG. 5, socket lead 15 will be described
hereinafter in detail. As mentioned above, each socket lead 15
comprises inner connection portion 15a, elastic portion 15b, and
outer connection portion 15c. Inner connection portion 15a makes a
contact with outer leads 22 of semiconductor integrated circuit
device 20, and outer connection portion 15c makes a contact with
circuit board 30. Elastic portions 15b are bent so that inner
connection portion 15a contacts outer lead 22 when upper body 12
sits on lower body 13. That is, inner connection portions 15a
contact outer leads 22 of semiconductor integrated circuit device
20 when upper body 12 of socket 10 moves down, and disconnect from
outer leads 22 when upper body 12 moves up to release semiconductor
integrated circuit device 20 from socket 10.
[0030] As shown in FIG. 6, outer connection portion 15c of this
embodiment has a shape of elliptical hook for easy insertion and
removal of outer connection portion 15c of socket lead 15 into and
from a through hole 33 of circuit board 30. In addition, this shape
provides elasticity to outer connection portion 15c of socket lead
15. The width d1, between the leftmost point and the rightmost
point of outer connection portion 15c, is greater than the diameter
(d2 in FIG. 7) of through hole 33. When socket lead 15 is inserted
into through hole 33, outer connection portion 15c is squeezed in
the direction of arrow "B" and pushes inner wall 32 of through hole
33 in the direction of arrow "A" to make a contact with through
hole 33. Through hole 33 connected to a tester (not shown) by
wiring for transferring electrical signals between the tester and
circuit board 30. When socket lead 15 is removed from through hole
33, outer connection portion 15c recovers its initial shape.
[0031] FIG. 7A and FIG. 7B are schematic cross-sectional views
respectively showing socket lead 15 before and after being inserted
into circuit board 30, respectively. With reference to FIG. 7a and
FIG. 7b, the outer connection portion 15c of socket lead 15 will be
described in detail hereinafter.
[0032] With reference to FIG. 7A, the appropriate width d1 of the
central portion of the outer connection portion 15c is determined
by inner diameter d2 of through hole 33 of circuit board 30.
Generally, width d1 is greater than inner diameter d2 to such
degree that outer connection portion 15c maintains its elasticity
without a plastic deformation of the elliptical hook shape of outer
connection portion 15c after an extended use of socket 10.
Preferably, 0.1 mm difference between width d1 and diameter d2 can
give the elasticity without plastic deformation to outer connection
portion 15c of socket lead 15. In one embodiment of the present
invention, socket lead 15 is made of a conductive material such as
copper on a copper alloy, and outer connection portion 15c is a
loop of wire having a diameter of 0.27 mm. The loop has a width d1
of about 0.86 mm and a height of about 1.94 mm. Through hole 33 is
circular with a diameter of about 0.75 mm and inner wall 32 is made
of materials such as copper and gold that are conductive,
abrasion-resistant, and oxidation-resistant.
[0033] In this embodiment, when outer connection portion 15c of
socket lead 15 is in through hole 33 as shown in FIG. 7b, the
elastic force from the compressed elliptical hook shape of outer
connection portion 15c maintains the contact between inner wall 32
of through hole 33 and outer connection portion 15c. Herein, the
location and size of the contact points between outer connection
portion 15c and through hole 33 may be variously controlled by
changing the shape and the degree of the bent portion of outer
connection portion 15c.
[0034] Another advantage of the elliptical hook shape is a
minimized friction between inner wall 32 of through hole 33 and
outer connection portion 15c of socket lead 15 during insertion of
socket lead 15 into through hole 33. Since the lower half of outer
connection portion 15c has a "V" shape, it is possible to minimize
the friction which is caused when inserting outer connection
portion 15c into through hole 33 of circuit board 30. The "V" shape
also helps align socket lead 15 with the associated through hole
33. In particular, if socket lead 15 is slightly misaligned, the
point end of outer connection portion 15c will guide socket lead 15
into proper alignment during insertion. The upper half of outer
connection portion 15c has an inverted "V" shape, which minimizes
the friction when removing outer connection portion 15c from
through hole 33 of circuit board 30.
[0035] The length of outer connection portion 15c can be such that
outer connection portion 15c does not protrude below the lower
surface of circuit board 30, when outer connection portion 15c is
inserted in through hole 33 of circuit board 30. In the case of the
conventional socket, in which outer connection portion of socket
lead should be connected to a circuit board by soldering, the outer
connection portion protrudes from through hole below the lower
surface of the circuit board. However, in the present invention,
since outer connection portion 15c does not have to protrude from
through hole 33 outside the lower surface of circuit board 30, and
the total height of circuit board 30 can be smaller than that of
the circuit board for the conventional socket. Further, since the
lower surface of circuit board 30 of the present invention is flat
and even, the operation of an apparatus that loads and unloads the
socket may be improved. Inner wall 32 of through hole 33 of circuit
board 30 is made of conductive materials that are resistant to
abrasion and oxidation, because inner wall 32 must withstand
repeated insertion and removal of socket lead 15 into and from
through 33. Preferably, a gold layer can be plated on the inner
wall 32 of through hole 33, so that inner wall 32 can sustain its
conductivity after an extended use of circuit board 30.
[0036] FIG. 8 is a cross-sectional view showing another embodiment
of an outer connection portion 16c of a socket lead 16 according to
the present invention. In FIG. 8, outer connection portion 16c of
socket lead 16 has an .sup.2S.sup.2 shape. When socket 10 is loaded
on circuit board 30, the end of outer connection portion 16c of
socket lead 16 is inserted into through hole 33. The dimension of
"S" is selected to provide an elastic contact between inner wall 32
and outer connection portion 16c. For example, the width between
the rightmost point and the leftmost point of the "S" shape is
greater than the inner diameter of through hole 33. When being
inserted into through hole 33, outer connection portion 16c becomes
somewhat squeezed and flat and pushes inner wall 32 of through hole
33 at points E and F, because "S" shaped outer connection portion
16c tries to expand against wall 32.
[0037] Next, an embodiment of a sub-circuit board according to the
present invention will be described hereinafter.
[0038] FIG. 9 is a cross-sectional view showing another connection
method between a socket 50 and a circuit board 30 using a
sub-circuit board 60 according to the present invention.
Sub-circuit board 60 according to the present invention
electrically connects socket 50, especially for fine-pitch packages
of semiconductor integrated circuit device, to circuit board
30.
[0039] In FIG. 9, sub-circuit board 60 includes a wiring pattern
68, through hole 63 and connection pins 65. Wiring pattern 68
electrically connects the outer connection portion (not shown) of
socket 50 to respective through holes 63. Solder 66 fixes
connection pins 65 to respective through holes 63. The outer
connection portion of connection pin 66 are shaped for insertion
into through hole 33 of circuit board 30 in the same manner as
outer connection portion 15c in FIG. 5.
[0040] The present invention can be applied in various ways. First,
the shape of the outer connection portion is not limited to an
elliptical hook shape or an .sup.2S.sup.2 shape. That is, the outer
connection portion of the socket can be formed in any shape that
gives elasticity to the outer connection portion of socket lead and
contacts the inner wall of the associated through hole. Second, the
socket and the circuit board according to the present invention are
not limited to those which are used for burn-in test or electrical
characteristics test of semiconductor integrated circuit devices.
That is, the present invention may be applied to a socket and a
circuit board wherever the socket is connected to the circuit
board. Third, the shape of the inner connection portion of socket
lead is not limited to the shape described above. The inner
connection portion can have various shapes according to the type of
the outline of semiconductor integrated circuit device, including
but not limited to shapes for CSPs (Chip Scale Packages) and FPBGA
(Fine Pitch Ball Grid Array) packages. In the cases of CSPs and
FPBGA packages, since the solder balls of the packages are
equivalent of the outer leads of conventional plastic packages, the
inner connection portions of sockets contact the solder balls.
[0041] An experiment was carried out to evaluate the performance of
the socket according to the embodiment in FIG. 5. The change of the
width and the contact resistance of outer connection portions of
socket leads were measured after repeated insertion and removal of
the socket leads into and from the circuit board under a burn-in
test condition. Initial widths of outer connection portion of four
sockets were 0.86.+-.0.03 mm, and the diameters of the through
holes of circuit board were smaller than the width of the outer
connection portion by about 0.1 mm. After the sockets were inserted
and removed twenty times, the widths of the outer connection
portions decreased by only about 0.017.about.0.029 mm. Accordingly,
this result proves that the outer connection portion of the socket
can maintain its initial dimension up to twenty times of insertion
and removal of the socket.
[0042] Table 1 shows the change of contact resistance after
repeated insertion and removal of six socket leads into and from
the through holes of the circuit board.
1 TABLE 1 times 5 10 15 20 25 30 average 18.86 18.64 18.79 18.63
19.07 19.29 m.OMEGA. m.OMEGA. m.OMEGA. m.OMEGA. m.OMEGA.
m.OMEGA.
[0043] As shown in Table 1, the contact resistance change after
thirty insertions and removals of the socket leads was only 0.43
m.OMEGA.. In other words, the quality of electrical connection
between the socket and the circuit board was not seriously affected
by repeated insertion and removal of the sockets into and from the
through holes of the circuit board.
[0044] In summary, the present invention can eliminate the
soldering process for fixing socket leads to test circuit boards
and reduce the total cost for testing semiconductor integrated
circuit devices due to the non-use of receptacles, compared with
conventional connection methods described earlier. Moreover, the
present invention makes the replacement of a socket on a circuit
board easy.
[0045] Although embodiments of the present invention have been
described in detail hereinabove, it should be clearly understood
that many variations and/or modifications of the basic inventive
concepts herein taught will still fall within the spirit and scope
of the present invention as defined in the appended claims.
* * * * *