JP2002040049A - Contact probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact probe suitable for a probe test in a high frequency area which is integrally assembled into one barrel. SOLUTION: This contact probe 1 comprises a barrel 2, a plunger 3, a ball 4 and a compression coil spring 5. A highly conductive conductive film 8 is formed on the inner surface of the barrel 2, the whole surface part of the ball 4 is formed of an insulating material, and an insulating film is formed on the whole surface part of the compression coil spring 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a contact probe used for a probe test, and more particularly to a contact probe suitable for a probe test performed in a high frequency range.

2. Description of the Related Art Conventionally, when performing a probe test on various integrated circuits, a contact probe device having thousands of contact probes mounted on a printed board and a holding plate is electrically connected to a control unit of an inspection device. And perform a probe test.

[0002] As the contact probe, those having various structures are put to practical use. For example, a metal barrel (sleeve body), a metal plunger mounted on the barrel so as to be able to move forward and backward, a metal sphere mounted in the barrel and in contact with the base end of the plunger, and a sphere mounted in the barrel There is also a contact probe formed of a metal compression coil spring or the like that elastically urges the plunger toward the advance side through the contact probe. In this contact probe, a sphere is not essential, and a contact probe without a sphere is also in practical use.

On the other hand, Japanese Patent Application Laid-Open No. 11-174084 discloses a contact probe suitable for performing a probe test in a high frequency range. The contact probe includes a barrel connected to a test circuit on a printed circuit board, a plunger slidably mounted on the barrel,
It has a compression coil spring that is mounted in a hole of an insulating holding plate below the printed circuit board and urges the plunger toward the advancing side, and an insulating member interposed between the plunger and the compression coil spring.

[0004]

When a probe test is performed in a high frequency range of 1 to 3 GHz using a contact probe including the barrel, a plunger, and a compression coil spring, a test current also flows through the compression coil spring, The influence of self-inductance becomes remarkable, crosstalk is likely to occur between adjacent contact probes, the attenuation rate of the output signal with respect to the input signal increases, the response of the output waveform to the input waveform decreases, There is such a problem. This is the same in the case of a contact probe including a barrel, a plunger, a sphere, and a compression coil spring.

In the contact probe disclosed in Japanese Patent Application Laid-Open No. 11-174084, the length of the barrel is shortened, and the compression coil spring is attached to the outside of the barrel without being housed in the barrel. Insulating member is attached. With such a configuration, the influence of the self-inductance of the compression coil spring can be eliminated. However, without accommodating the compression coil spring in the barrel,
A structure in which a compression coil spring is accommodated in a hole of an insulating holding plate, and a part of a plunger partially protrudes into the hole of the holding plate to urge the plunger with the compression coil spring, so that a contact probe is incorporated in one barrel. Cannot be configured as one having the unity.

[0006] As a result, a large number of contact probes are manufactured in advance, and the assemblability when assembling the contact probe device by mounting them on a printed circuit board and a probe mounting plate (holding plate) is reduced. Is not integrated into one barrel, so if one of the contact probes does not work properly due to poor contact etc., much labor is required to replace only the failed contact probe with another contact probe. It will take time. The purpose of the present invention is
An object of the present invention is to provide a contact probe which is suitable for a probe test in a high frequency region and which is integrated into one barrel.

[0007]

According to a first aspect of the present invention, there is provided a contact probe to be used for a probe test, wherein a barrel, a plunger mounted on the barrel so as to be able to advance and retreat, and a plunger mounted in the barrel to advance the plunger. A compression coil spring that elastically urges, a highly conductive conductive film is formed on the inner surface of the barrel, and an insulating film is formed on the entire surface of the compression coil spring.

This contact probe is suitable for a probe test performed in a high-frequency region. In the probe test, a high-frequency signal for test is transmitted from a test circuit to a barrel with a plunger in contact with a terminal of an integrated circuit. Supply and test. At this time, the high-frequency signal flows on the inner surface of the barrel through the highly conductive conductive film and the plunger, but since the insulating film is formed on the entire surface of the compression coil spring, the high-frequency signal flows through the compression coil spring. Since the signal does not flow, the influence of the self-inductance of the compression coil spring does not appear on this high-frequency signal.

According to a second aspect of the present invention, in the contact probe according to the first aspect of the present invention, a sphere is provided in the barrel, between the base end face of the plunger and the compression coil spring,
At least the entire surface of the sphere is made of an insulating material. As described above, since at least the entire surface of the sphere is made of an insulating material, no high-frequency signal flows through the sphere and the electric resistance does not increase due to the sphere.

A third aspect of the present invention is the contact probe according to the second aspect, wherein the sphere is made of an insulating material. Therefore, even if the sphere is worn, the insulation of the sphere can be ensured and the durability is excellent.

According to a fourth aspect of the present invention, there is provided the contact probe according to any one of the first to third aspects, wherein the insulating film formed on the entire surface of the compression coil spring is a synthetic resin film formed by chemical vapor deposition. It is characterized by being. Therefore, an insulating film can be easily formed on the entire surface of the compression coil spring by chemical vapor deposition.

[0012]

Embodiments of the present invention will be described below. The contact probe according to the present embodiment uses a semiconductor integrated circuit in a high frequency region (for example, 1 to 3 GHz).
It is suitable for the probe test in z). As shown in FIGS. 1 and 2, the contact probe 1 includes a barrel 2, a plunger 3, a sphere 4, a compression coil spring 5, and the like.
The barrel 2 is mounted and mounted in a straight mounting hole 6a of the holder 6, and the barrel 2 is electrically connected to a test circuit 7a of the printed circuit board 7 by soldering. A large number of contact probes 1 are mounted in a matrix on the holder 6 and the printed circuit board 7, and a probe test is performed via the large number of contact probes 1.
A description will be given by taking one contact probe 1 as an example.

The barrel 2 is a bottomed thin cylindrical body made of phosphor bronze or brass. The outer diameter of the barrel 2 is, for example, 1.0 m.
m and the length are, for example, 10.5 mm. A highly conductive conductive film 8 is formed on the inner surface of the barrel 2. The conductive film 8 is, for example, a film of Au (gold) having a thickness of 5 to 15 μm. The conductive film 8 is formed to reduce the electric resistance to a high-frequency signal flowing on the surface of the conductor when performing a probe test in a high-frequency region. Barrel 2
A locking portion 9 for locking the large-diameter portion 13 of the plunger 3 is formed at a tip end of the plunger 3. An approximately 1/3 length portion on the base end side of the barrel 1 is an inclined portion 11 inclined, for example, by approximately 5.5 degrees via the bent portion 10.

The plunger 3 is a solid body made of, for example, beryllium copper, and has a plunger body 12 having an outer diameter of, for example, 0.55 mm, and a large-diameter portion 13 on the base end side slidably mounted in the barrel 2. Are integrally formed. Plunger 3
Is formed to be able to advance and retreat with respect to the barrel 2. At the tip of the plunger body 12, for example,
4 are formed. However, the shape of the tip is not limited to this shape. Large diameter part 1 of plunger 3
The base end surface of No. 3 is formed on an inclined surface 15 inclined several degrees from a surface orthogonal to the axis. This is because the outer peripheral surface of the large diameter portion 13 is brought into strong contact with the inner surface of the barrel 2 by the pressing force acting on the large diameter portion 13 from the sphere 4.

The sphere 4 is, for example, a sphere made of stainless steel and is movably mounted in the barrel 2 between the inclined surface 15 at the base end of the large diameter portion 13 of the plunger 3 and the compression coil spring 5. The elastic urging force is transmitted to the plunger 3. At least the entire surface of the sphere 4 is made of an insulating material. That is, the insulating film 1 made of a synthetic resin material having excellent insulation properties is applied to the entire surface of the sphere 4.
6 (thickness, for example, 3 to 5 μm) is formed by CVD (chemical vapor deposition) (see FIG. 3). The insulating coating 16 of the synthetic resin material is, for example, a coating made of polyparaxylene among xylene resins. However, the insulating film 16 may be made of a synthetic resin material having an insulating property different from xylene resin, or may be made of a metal oxide film.

The compression coil spring 5 is a coil spring made of a thin piano wire, and an insulating film 17 made of a synthetic resin material having excellent insulation properties is formed on the entire surface of the compression coil spring 5 (see FIG. 4). ). The insulating coating 17 made of a synthetic resin material is, for example, a coating made of polyparaxylene among xylene resins. However, the insulating film 17 may be made of a synthetic resin material having an insulating property different from xylene resin, or may be made of a metal oxide film. The insulating film 17 formed on the entire surface of the compression coil spring 5 is provided to prevent a high-frequency test current from flowing through the compression coil spring 5.

Next, the contact probe 1 described above
The operation of will be described. At the time of the probe test, with the plunger 3 in contact with the terminal of the integrated circuit, the barrel 2 is connected to the barrel 2 via the test circuit 7a of the printed circuit board 7 from the inspection device.
The test is performed by supplying a high-frequency signal for test to the tester. At this time, the high-frequency signal flows through the highly conductive conductive film 8 on the inner surface of the barrel 2 and the plunger 3, but since the insulating film 17 is formed on the entire surface of the compression coil spring 5, the high-frequency signal is Since there is no flow in the compression coil spring 5, the influence of the self-inductance of the compression coil spring 5 does not appear on this high-frequency signal. Since the highly conductive conductive film 8 is formed on the inner surface of the barrel 2, the high frequency signal of the probe test flows through the highly conductive conductive film 8 and the plunger 3.

Therefore, it is possible to prevent the occurrence of crosstalk between the adjacent contact probes 1, prevent the output signal from being attenuated with respect to the input signal from increasing, and prevent the response of the output signal to the input signal from deteriorating. Can be prevented. Since the spherical body 4 is mounted in the barrel 2 and between the inclined surface 15 at the base end of the plunger 3 and the compression coil spring 5, and at least the entire surface of the spherical body 4 is made of an insulating material, a high-frequency signal is also applied to the spherical body 4. It does not flow, and the electric resistance does not increase under the influence of the sphere 4. Compression coil spring 5
Since the insulating film 17 formed on the entire surface of the compression coil spring 5 is a synthetic resin film formed by chemical vapor deposition, the insulating film 17 can be easily formed on the entire surface of the compression coil spring 5 by chemical vapor deposition. it can.

Moreover, in the contact probe 1, the plunger 3, the sphere 4 and the compression coil spring 5 are mounted on the barrel 2, and in particular, the compression coil spring 5 in the barrel 2 is mounted to form an integral contact probe. Therefore, the mountability when attaching a large number of contact probes 1 to the holder 6 and the printed circuit board 7 does not decrease, and if the contact probe 1 breaks down, it can be easily replaced with a new contact probe. Can be exchanged.

The sphere 4 need not be made of a metal material, and the whole sphere 4 may be made of an insulating material such as a synthetic resin material. In this case, the insulation of the sphere can be ensured even by wear of the sphere 4, and the durability is excellent. Further, the spherical body 4 is not essential and may be omitted, and the compression coil spring 5 may directly elastically bias the plunger 3. Further, the bent portion 10 of the barrel 2 of the contact probe 1 can be omitted, and the diameter and length of the barrel 2 and the diameter, length and shape of the plunger 3 described above are merely examples, and are formed in various sizes and shapes. Is done. In addition, those skilled in the art can implement the above-described contact probe 1 in various modified forms without departing from the spirit of the present invention.

[0021]

According to the first aspect of the present invention, a high-conductive conductive film is formed on the inner surface of the barrel, and an insulating film is formed on the entire surface of the compression coil spring. Since the high-frequency signal does not flow through the compression coil spring through the highly conductive conductive film and the plunger on the inner surface of the first coil, the influence of the self-inductance of the compression coil spring does not appear on the high-frequency signal.

In this contact probe, a plunger and a compression coil spring are mounted on the barrel, and in particular, a compression coil spring is mounted in the barrel.
The integrity of the contact probe can be ensured. as a result,
The assemblability when assembling a large number of contact probes to the probe mounting plate does not deteriorate, and even when the contact probe breaks down, it can be easily replaced with a new contact probe.

According to the second aspect of the present invention, a sphere is provided in the barrel and between the base end face of the plunger and the compression coil spring, and at least the entire surface of the sphere is made of an insulating material. Also, no high-frequency signal flows, and the electric resistance does not increase due to the influence of the sphere. The other effects are the same as those of the first aspect.

According to the third aspect of the present invention, since the sphere is made of an insulating material, the insulation of the sphere can be ensured even when the sphere is worn, and the durability is excellent. Other effects are the same as those of the second aspect.

According to the fourth aspect of the present invention, the insulating film formed on the entire surface of the compression coil spring is a synthetic resin film formed by chemical vapor deposition. An insulating film can be easily formed by chemical vapor deposition.

[Brief description of the drawings]

FIG. 1 is a side view of a contact plunger according to an embodiment of the present invention.

FIG. 2 is a sectional view of a contact plunger.

FIG. 3 is an enlarged sectional view of a sphere.

FIG. 4 is an enlarged sectional view of a main part of the compression coil spring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contact probe 2 Barrel 3 Plunger 4 Sphere 5 Compression coil spring 8 Conductive film 16 Insulating film 17 Insulating film

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G003 AA07 AG03 AH05 2G011 AA09 AB01 AB03 AC31 AD01 AE22 AF07 4M106 AA01 AA02 AA04 BA01 CA01 CA09 DD04 DD06 DD15

Claims (4)

[Claims] 1. A contact probe for use in a probe test, comprising: a barrel; a plunger mounted on the barrel so as to be able to move forward and backward; and a compression coil spring mounted in the barrel to elastically bias the plunger toward an advance side. A contact probe having a highly conductive film formed on an inner surface of a barrel and an insulating film formed on the entire surface of a compression coil spring. 2. A sphere mounted in the barrel and between the base end face of the plunger and the compression coil spring, and at least the entire surface of the sphere is made of an insulating material. Contact probe. 3. The contact probe according to claim 2, wherein said sphere is made of an insulating material. 4. The method according to claim 1, wherein the insulating film formed on the entire surface of the compression coil spring is a film made of a synthetic resin formed by chemical vapor deposition. Contact probe.