Socket, circuit board, and sub-circuit board for...

Details Socket, circuit board, and sub-circuit board for... Socket, circuit board, and sub-circuit board for...

1998-09-23

2002-09-17

Sircus, Brian (Department: 2839)

Electrical connectors

With insulation other than conductor sheath

Metallic connector or contact secured to insulation

C439S070000, C439S082000

Reexamination Certificate

active

06450839

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
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.
2. Description of the Related Arts
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.
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
.
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.
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.
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.
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
95
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
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.
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.
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.
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.
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.


REFERENCES:
patent: 3264597 (1966-08-01), Gammel, Sr.
patent: 3634819 (1972-01-01), Evans
patent: 3717841 (1973-02-01), Mancini
patent: 3880493 (1975-04-01), Lockhart, Jr.
patent: 3924921 (1975-12-01), Feightner
patent: 3958859 (1976-05-01), Schmid
patent: 4217024 (1980-08-01), Aldridge et al.
patent: 4362353 (1982-12-01), Cobaugh et al.
patent: 4655537 (1987-04-01), Andrews
patent: 4715823 (1987-12-01), Ezura et al.
patent: 5160270 (1992-11-01), Reymond
patent: 5186634 (1993-02-01), Thompson
patent: 6213817 (2001-04-01), Jeong et al.
patent: 2806683 (1979-08-01), None

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