Contact probe and probe device

Details Contact probe and probe device Contact probe and probe device

2002-02-19

2004-03-23

Cuneo, Kamand (Department: 2829)

Electricity: measuring and testing

Fault detecting in electric circuits and of electric components

Of individual circuit component or element

C324S761010, C324S762010

Reexamination Certificate

active

06710608

ABSTRACT:

CROSS REFERENCES TO RELATED APPLICATIONS
This application claims priority to Japanese Patent Application 8-128570 filed May 23, 1996, Japanese Patent Application 8-259829 filed Sep. 30, 1996, Japanese Patent Application 8-259831 filed Sep. 30, 1996, Japanese Patent Application 8-303322 filed Nov. 14, 1996, Japanese Patent Application 8-306829 filed Nov. 18, 1996, Japanese Patent Application 8-324430 filed Dec. 4, 1996, and Japanese Patent Application 8-349119 filed Dec. 26, 1996, all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a contact probe used as a probe pin, or a socket pin etc., for electrical testing of devices, such as semiconductor IC (Integrated Circuit) chips, liquid crystal devices, etc., and more particularly to a contact probe integrated into a probe card, a probe device, a test socket, etc. and which are brought into contact with respective terminals of a device under test.
2. Description of Related Art
Contact pins are generally used for carrying out an electrical testing by being brought into contact with respective terminals of a device under test, for example, such as a semiconductor chip, such as an IC chip, an LSI (Large Scale Integrated Circuit) chip, an LCD (Liquid Crystal Display), etc.
In recent years, with high integration and miniaturization of devices, such as IC chips etc., contact pads configured as electrodes formed with a narrow pitch, multi pins, and narrow pitch contact pins have been required. According to one solution to the above requirements, a contact probe made of tungsten needles used as contact pins has been proposed. However; with this solution it is difficult to deal with multi pins and narrow pitch requirements due to a limitation in the diameter of the tungsten needles.
In Japanese Examined Patent Publication No. JP-B-7-82027, a contact probe technology where a plurality of wiring patterns are formed on a resin film and respective front end portions of the wiring patterns are arranged to project from the resin film to form contact pins is proposed. According to this technology, a probe device having multi pins and narrow pitch is possible and numerous complex parts are not required as compared to other technologies. As shown in
FIG. 110
, a conventional contact probe
1
A has a structure where wiring patterns
3
A formed from Ni (nickel) or a Ni alloy are attached on one face of a polyimide resin film
2
A and front end portions of the wiring patterns
3
A are projected from an end portion of the resin film
2
A so as to form contact pins
3
aA. In
FIG. 110
, positioning holes
4
A are formed in the polyimide resin film
2
A as will be described later.
Japanese Unexamined Patent Publication No. JP-A-6-324081 proposes a probe device (probe card) using contact probes having a flexible substrate, as in the previously discussed publication, where front end portions of wiring patterns constitute contact pins. According to this probe device, a matching is conducted with respect to a difference in pin pitches of an IC chip or device under test, etc. and a tester. The proposed probe device is suitable for probe testing an IC chip etc. having multi pins and narrow pitch.
FIGS. 111-113
will now be used to explain the operation of a conventional probe device
11
A where a contact probe
1
A is integrated with a mechanical parts
10
A. The mechanical parts
10
A include a mounting base
12
A, a top clamp
13
A and a bottom clamp
14
A. The probe device
11
A includes the top clamp
13
A securing a printed circuit board
15
A, the mounting base
12
A, and the contact probe
1
A via a bottom clamp
14
A. The bottom clamp
14
A is attached to the top clamp
13
A by bolts
17
A and bolt holes
16
A. The contact probe
1
A having wiring patterns
3
A (
FIG. 110
) is pressed by the bottom clamp
14
A, so that the wiring patterns
3
A press against an IC chip under test while being maintained in a constant inclined state.
FIG. 112
illustrates the probe device
11
A of
FIG. 111
after assembly.
FIG. 113
is a sectional view taken along a line E—E of FIG.
112
. As shown in
FIG. 113
, the front ends of the wiring patterns
3
A are brought into contact with an IC chip I by the mounting base
12
A. The mounting base
12
A is provided with positioning pins
18
A for adjusting the position of the contact probe
1
A, and the wiring patterns
3
A. Thus, the IC chip I can be accurately positioned by inserting the positioning pins
18
A into the positioning holes
4
A of the contact probe
1
A. Elastic bodies
20
A of the bottom clamp
14
A are pressed against portions of the wiring patterns
3
A at windows
19
A provided in the contact probe
1
A. In this way, the wiring patterns
3
A at the windows
19
A are brought into contact with electrodes
21
A of the printed circuit board
15
A forming a signal path by which signals obtained from the wiring patterns
3
A can be transmitted via the electrodes
21
A of the printed circuit board
15
A.
However, the above-described conventional contact probe
1
A has the following problems. As shown in
FIG. 114
, the contact pins
3
a
A of the conventional contact probe
1
A are attached on one face of the resin film
2
A. However, the resin film
2
A is fabricated from, for example, polyimide resin and therefore, the resin may be elongated by absorbed moisture changing an interval t between the contact pins
3
a
A. Accordingly, the contact pins
3
a
A may not accurately contact pads of an IC chip, or device under test, etc. and therefore, an accurate electrical test cannot be conducted. Furthermore, although the positioning holes
4
A for integrating the contact probes
1
A to the probe device
11
A are provided in the resin film
2
A of the contact probe
1
A, the resin film
2
A has a small hardness value and accordingly, the positioning holes
4
A are susceptible to being deformed. Therefore, accurate positioning of the contact probe
1
A cannot be performed.
Furthermore, according to the contact probe
1
A (FIGS.
110
-
113
), during testing of a device, an amount of pressure applied to contact pins of the contact probe is increased or decreased to provide a desired contact pressure. A large amount of pressure must be applied to the contact pins in order to provide a large contact pressure. However, according to the first type of contact probe, front end portions of wiring patterns of the contact probe are used to form the contact pins. The contact pins are made from a material such as Ni (nickel). Therefore, a hardness of the contact pins is typically about Hv 300. Due to the low hardness of the contact pins
3
a
A, the contact pins may be bent or deformed under excessive contact pressure. Accordingly, there is a limited amount of pressure that can be exerted on the contact pins so that a large contact pressure cannot be obtained. Therefore, a sufficient contact pressure cannot be obtained during electrical measurements of a device under test, resulting in contact failure.
To solve the above problem, there is provided a means of adding an additive agent, such as saccharin etc. in the Ni plating of the contact pins. Although at normal temperature the contact pins have a hardness of Hv 350 or more, the hardness of the contact pins drops rapidly to Hv 200 or less when the contact pins are heated to a high temperatures (e.g., 300° C.). This is due to the S (sulphur) content of the additive agent, such as saccharin etc. which reduces the contact pin hardness at high temperatures. Therefore, the above-described contact probe cannot typically be used at high temperatures, particularly when the contact probe is used as a chip carrier for a burn-in test, etc. which subjects the contact probe to high temperatures.
In addition, surfaces of respective terminals (pads) of an IC chip, etc. are typically made from a material, such as an Al (aluminum) alloy, etc. When such terminals are exposed to air, oxidation occurs and the terminals have a thin aluminum oxide film formed thereon. Therefore, during electrical testing, the aluminum

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