IC socket

Details IC socket IC socket

2001-02-26

2003-04-15

Graybill, David E. (Department: 2827)

Metal working

Barrier layer or semiconductor device making

Reexamination Certificate

active

06547837

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to IC sockets.
2. Description of the Related Art
There has been proposed an IC socket having a plurality of contact pins for connection with the terminals of a semiconductor package to test the electrical characteristics of the semiconductor package.
FIG. 2
shows a first example of a conventional IC socket with a contact pin in contact with the terminal of a semiconductor package.
FIG. 3
shows the contact pin of a second conventional IC socket in contact with the terminal of a semiconductor package.
In
FIG. 2
, a semiconductor package
51
has a plurality of terminals
52
. An IC socket body
53
has the corresponding number of metal contact pins
54
to the number of the terminals
52
. Each contact pin
54
is provided at a position corresponding to the position of each terminal
52
such that the contact portion
57
is brought into contact with the terminal
52
for connection to measuring equipment (not shown). A pressure member
55
is pressed downwardly by a pressing device (not shown) so as to press the terminal
52
against the contact portion
57
. The contact pin
54
has a substantially U-shaped form to provide flexibility and is provided in a groove
56
of the socket body
53
so that the contact portion
57
is flexible downwardly.
Where a large amount of solder or dust particles (hereinafter “solder”) is adhered to the back side of the terminal
52
, the electrical contact between the terminal
52
and the contact pin
54
becomes so poor that it becomes defective. The dust particles are usually wastes of mold resins and fillers. An excessive amount of solder applied to the terminal
52
also causes poor contact. If there is a poor contact between the backside of the terminal
52
and the contact portion
57
of the contact pin
54
, it is impossible to conduct appropriate test of the electrical characteristics of a semiconductor package.
Consequently, the contact portion
57
is provided with a first contact face
57
a
and a second contact face
57
b
so that when the terminal
52
is pressed against the contact pin
54
, the first contact face
57
a
slides on the back side of the terminal
52
to wipe out the “solder” from the back side and then the second contact face
57
b
makes contact with the wiped and cleaned backside of the terminal
52
. This makes a good electrical contact between the backside of the terminal
52
and the contact portion
57
of the contact pin
54
.
In
FIG. 3
, the contact portion
57
of the contact pin
54
is provided with a plurality of triangular projections, forming a saw tooth configuration.
Similarly to the first example, when the terminal
52
is pressed against the contact portion
57
of the contact pin
54
, the projections of the contact portion
57
wipe the backside of the terminal
52
to remove the “solder” from the backside so that the tips of the projections are brought into contact with the cleaned backside of the terminal
52
. This makes a good electrical contact between the backside of the terminal
52
and the contact portion
57
of the contact pin
54
. In addition, the “solder” removed from the backside is kept as remains
59
between the projections.
In the above IC sockets, however, the entire backside of the terminal
52
is wiped so that a large amount of “solder” is removed and scattered, contaminating the surrounding atmosphere. In the above second example, the “solder” is kept between the projections as remains
59
so that when the amount of the remains
59
becomes large, the remains
59
fall out and spread to contaminate the surrounding atmosphere.
If the surrounding atmosphere is contaminated, unexpected short-circuitry, etc. occurs, making it impossible to test the electrical characteristics of the semiconductor package. In addition, if the semiconductor package or manufacturing equipment is contaminated, the manufactured semiconductor package becomes defective, reducing the throughput or yield of the semiconductor manufacturing process.
If a large amount of “solder” accumulate on the contact portion
57
of the contact pin
54
, the electrical contact between the backside of the terminal
52
and the contact portion
57
of the contact pin
54
is blocked. If the force to press the terminal
52
against the contact pin
54
is reduced so as to control the amount of “solder” removed by wiping, the contact pressure between the backside of the terminal
52
and the contact portion
57
of the contact pin
54
becomes too low to provide good contact. Where the “solder” adhered to the backside of the terminal
52
is waste of the mold resin or filler, the adhering power is so high that the waste is not removed by wiping. Consequently, the electrical contact between the backside of the terminal
52
and the contact portion
57
of the contact pin
54
is blocked.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide an IC socket capable of removing a small amount of “solder” without contaminating the surrounding atmosphere and eliminating poor contacts caused by an unsatisfactory contact pressure between the backside of the terminal
52
and the contact portion
57
of the contact pin
54
or remains of “solder” adhered to the backside of the terminal
52
, thus making it possible to conduct appropriate test of the electrical characteristics of a semiconductor package.
According to the invention there is provided an IC socket which comprises a socket body and a contact pin with a contact face supported by the socket body such that it is flexible toward the inside of the socket body. The contact face is made by rounding an upper rectangular portion of the contact pin for contact with the terminal of a semiconductor package.


REFERENCES:
patent: 4927369 (1990-05-01), Grabbe et al.
patent: 5159266 (1992-10-01), Appold
patent: 5481203 (1996-01-01), Appold
patent: 5742171 (1998-04-01), Matsunaga et al.

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