TW202229878A - Contact probe - Google Patents

Abstract

The present invention addresses the problem of providing a contact probe, the tip part of which can reliably contact an inspection point on a body to be measured, and which can be configured so as not to cut or damage the inspection point of the body to be measured. The problem is solved by a contact probe (10) having a body part (14) having an insulating film (12) on the outer periphery of a metal conductor (11), and end parts (16) which are formed at both ends of the metal conductor (11) and which do not have the insulating film (12), the contact probe (10) being bent by application of a load thereto in the axial direction, and thereby obtaining a contact pressure with respect to a body (20) to be measured and measuring an electrical characteristic thereof, wherein the surface shape of at least the end part (16) on the side contacting the body (20) to be measured from among the end parts (16) is curved, and R is in the range of more than 0.5D and no more than 5D, where R is the curvature radius of the curved surface, and D is the diameter of the metal conductor (11).

Description

touch probe

The present invention relates to a contact probe used for inspection of electrical characteristics of electronic components, substrates, and the like.

In recent years, various circuit boards have been used, such as high-density mounting boards for smartphones and mobile phones, and IC package boards such as BGA (Ball Grid Array) and CSP (Chip Size Package) incorporated into personal computers. These circuit boards are subjected to, for example, DC resistance value measurement and continuity inspection in the steps before and after installation to check whether the electrical characteristics are good or not.

For example, as shown in Patent Document 1, the inspection of electrical characteristics is performed using an inspection device jig (hereinafter, may be referred to as a probe unit) connected to the inspection device. Specifically, the tip of the probe is brought into contact with an electrode (hereinafter, may be referred to as a measurement object) of a circuit board (hereinafter, may be referred to as a measurement object) by contacting a pin-shaped (pin-shaped) tip attached to the tip of the probe unit. , sometimes referred to as checkpoints).

In Patent Document 2, it is described that the shape of the distal end portion of the contact probe can be suitably selected from any of a hemispherical shape, a conical shape, a conical shape with a hemispherical tip, and a conical shape with a flat tip.

In Patent Document 3, it is described that the shape of the front end portion of the contact probe is a flat shape. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2002-131334 Patent Document 2: Japanese Patent Laid-Open No. 2007-322369 Patent Document 3: Japanese Patent Laid-Open No. 2013-024716

[The problem to be solved by the invention]

As described in Patent Document 1 and Patent Document 2, if the shape of the front end of the touch probe is hemispherical, the front end of the touch probe may slide too much from the inspection point of the object to be measured, so that the The front end does not touch the inspection point, so correct inspection may not be possible.

In addition, as described in Patent Document 2, when the tip of the touch probe has a conical shape, a hemispherical tip has a conical shape, and a tip has a flat conical shape, due to the difference with the inspection point of the object to be measured Since the contact area becomes smaller, it may become difficult to make the front end of the contact probe come into contact with each inspection point for inspection due to the trend of narrowing the electrode pitch in recent years.

In addition, as described in Patent Document 3, when the shape of the tip of the touch probe is a flat shape, although the contact area with the inspection point of the object to be measured can be sufficiently ensured, since the tip of the touch probe is generated There is a right-angled edge, so when the edge is in contact with the inspection point, the inspection point may be cut off or scratched.

Therefore, the present invention has been made in order to solve the above-mentioned problems, and an object thereof is to provide a touch probe capable of reliably contacting the distal end of the touch probe with an inspection point of a to-be-measured body, and to reduce the need for the measurement of the body-to-be-measured body. Cuts or scratches caused by the inspection points. [means to solve the problem]

A contact probe according to the present invention is a contact probe comprising: a main body part having an insulating coating on the outer periphery of a needle-shaped metal conductor; and an end part formed on both ends of the metal conductor and not having the insulation The film is bent by applying a load in the axial direction to obtain a contact pressure on the object to be measured to measure electrical characteristics, wherein the shape of at least one of the ends on the side that is in contact with the object to be measured is a As for the curved surface, when R is the radius of curvature of the curved surface and D is the diameter of the metal conductor, R is in the range of more than 0.5D and 5D or less. By adopting this configuration, since the end portion in contact with the object to be measured can be formed into a substantially flat curved surface, it does not slip excessively when it contacts the inspection point of the object to be measured. In addition, since the edge portion is not a right angle, it is possible to In contact with the inspection point surface, it protects the inspection point from being chipped or scratched.

In addition, it is characterized in that the curvature radius R may be greater than or equal to D.

Moreover, it is characterized in that the diameter of the said metal conductor may be 8 micrometers or more and 180 micrometers or less. [Effect of invention]

According to the present invention, it is possible to provide a touch probe capable of reliably touching the inspection point of the object to be measured, and without chipping or scratching the inspection point of the object to be measured.

[Form for carrying out the invention]

Hereinafter, embodiments of the contact probe of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view of the contact probe, and FIG. 2 is an explanatory view when the contact probe is used to perform an inspection of the electrical characteristics of an object to be measured.

The contact probe 10 is composed of an extremely thin cylindrical (needle-shaped) metal conductor 11 with a circular cross section, and has a body portion 14 having an insulating coating 12 on the outer periphery of the metal conductor 11 . End portions 16 without the insulating coating 12 are formed at both ends of the metal conductor 11 . The contact probe 10 is configured so as to obtain a contact pressure on the object to be measured by applying a load in the axial direction to bend it, and to check the electrical characteristics.

(Inspection method for electrical characteristics using contact probes) The use of the contact probe will be described with reference to FIG. 2 . In the example shown here, an IC package substrate or the like is used as the object to be measured 20 , a plurality of electrodes formed on the surface of the object to be measured 20 are used as inspection points 22 , and the ends 16 of the contact probes 10 are brought into contact with the object to be measured 20 . Checkpoint 22.

The probe unit 30 , which is a jig for inspection, has a plurality of contact probes 10 . The probe unit 30 has an upper plate 32 for holding the upper ends of a plurality of contact probes 10 , and a lower plate for guiding the lower ends of the contact probes 10 . The upper plate 32 and the lower plate 34 are supported by a support column 36 . . A guide hole with a diameter slightly larger than that of the lower end of the contact probe 10 is formed in the lower plate 34 , and the lower end of the contact probe 10 can move axially in the guide hole. In addition, a plurality of lead wires 37 are arranged on the upper plate 32 to be electrically connected to the respective upper end portions of the plurality of contact probes 10 . The plurality of lead wires 37 are connected to a measuring machine (not shown) or a power source (not shown).

As shown in the right diagram of FIG. 2 , above the object to be measured 20 , the probe unit 30 is arranged so that the lower end of each contact probe 10 faces the position of each inspection point 22 of the object to be measured 20 . Then, the probe unit 30 is lowered so that the lower ends of the contact probes 10 come into contact with the inspection points 22 of the object 20 to be measured, and, as shown in the right diagram of FIG. 30 is pressurized. Then, a load is applied along the axial direction of the contact probe 10 to bend the contact probe 10 . At this time, the end portion 16 of the contact probe 10 is in contact with the inspection point 22 with a predetermined contact pressure formed by the elastic force generated by the bending of the contact probe 10 .

(metal conductor) As the metal conductor 11, a metal wire (also referred to as a metal spring wire) having high conductivity and high elastic modulus is used. As the metal material used for the metal conductor 11 , copper alloys such as tungsten, rhenium tungsten, and beryllium copper, palladium alloys, copper-silver alloys, and the like can be suitably used.

In order to suppress an increase in the contact resistance between the metal conductor 11 and the inspection point 22 of the object to be measured 20 or the lead wire 37 of the detection device, a plating layer may be provided on the surface of the metal material of the metal conductor 11 as required. Metals such as nickel, gold, and rhodium, and alloys such as gold alloys are exemplified as the metal forming the plating layer. The plating layer may be a single layer or multiple layers. As a multi-layered plating layer, for example, a gold plating layer is preferably formed on a nickel plating layer. The thickness of the plating layer is not particularly limited, but can be set to, for example, 1 μm or more and 5 μm or less.

The diameter of the metal conductor 11 of the present embodiment tends to be reduced in accordance with the demand for narrowing the pitch in recent years, and the conductor diameter of the metal conductor 11 of the present embodiment can be suitably used to be 8 μm or more and 180 μm or less. In addition, it is preferable to use a conductor whose diameter is within the range of 10 μm or more and 110 μm or less. The metal conductor 11 is manufactured by plastic working such as cold drawing or hot drawing so as to be a needle-shaped conductor of a predetermined diameter.

Furthermore, in order to easily install the contact probe 10 on the probe unit 30, and not get caught in the guide hole of the lower plate 34 of the probe unit 30, and not hinder the movement of the contact probe 10, preferably The metal conductor 11 with high straightness is used. Specifically, it is preferable that the straightness is a radius of curvature of 1000 mm or more. The metal conductor 11 with high straightness is obtained by straightening the elongated metal wire before the insulating film 12 is provided. The straight-line straightening process is performed by, for example, a rotary die-type straight-line straightening apparatus or the like.

(Ends) One end 16 of both ends of the metal conductor 11 is in contact with the inspection point 22 of the object to be measured 20 . As shown in FIG. 3 , in the contact probe 10 of the present embodiment, at least the shape of the end portion 16 of the both end portions of the metal conductor 11 that is in contact with the inspection point 22 of the object to be measured 20 is curved. In addition, when the radius of curvature of the curved surface is R, and the diameter of the metal conductor 11 is D, R may be preferably greater than 0.5D and less than 5D (hereinafter, it may be expressed as 0.5D<R≦5D in some cases) ) composition. However, in order to form a curved surface under the above-mentioned conditions, not only the one end portion 16 but also both end portions can be formed as curved surfaces under the above-mentioned conditions.

By setting the radius of curvature R of the curved surface of the end portion 16 to be 0.5D<R≦5D, the end portion 16 in contact with the inspection point 22 of the object to be measured 20 can be formed into a curved surface approximately close to a flat shape. Therefore, when the end portion 16 is brought into contact with the inspection point 22 of the object to be measured 20, excessive sliding is prevented. In addition, since the edge portion of the end portion 16 is not at a right angle, surface contact can be made with respect to the inspection point 22, and the inspection point 22 can be prevented from being chipped or scratched. In addition, the contact area with the inspection point 22 can be sufficiently secured.

As described above, if the diameter of the metal conductor 11 is 8 μm or more and 180 μm or less, for example, when D=8 μm, the curvature radius R of the end portion 16 is in the range of 4 μm<R≦40 μm, and when D=180 μm In the case of , the radius of curvature R of the end portion 16 is in the range of 90 μm<R≦900 μm.

In addition, as shown in FIG. 4, the touch probe 10 of this embodiment can be suitably used when it is arrange|positioned in the middle of the two inspection points 22 of the to-be-measured body 20. In addition, although the hemispherical inspection point 22 is shown in FIG. 4, the shape of the inspection point 22 is not limited to the shape mentioned above. In this case, the end portion does not slide excessively with respect to the hemispherical inspection point 22, and the contact area with the inspection point 22 can be sufficiently secured. In addition, since the edge portion of the end portion 16 is not at a right angle, it can come into surface contact with the inspection point 22 without chipping or scratching the two inspection points 22 .

As a method of forming the end portion 16 of the metal conductor 11 into the aforementioned shape, the end portion 16 of the metal conductor 11 is subjected to a grinding process. Grinding can be performed by using abrasive sandpaper, or by using a diamond wheel. In addition, a known grinding machine capable of grinding a needle-shaped metal material can also be used.

(insulating film) The material of the insulating film 12 is not particularly limited as long as it is an insulating film, and a material selected from the group consisting of polyurethane resin, nylon resin, polyester resin, epoxy resin, polyesterimide can be suitably used One or more resin materials of resin, polyamide resin, polyamide imide resin, etc. In addition, since the heat resistance of the insulating film 12 made of these resins varies depending on the type of resin, it can be arbitrarily selected in consideration of heat generated during inspection of the object to be measured 20 and ambient temperature.

The thickness of the insulating film 12 may be a thickness sufficient to ensure electrical insulating properties, and may be appropriately set within a range of 1 μm or more and 30 μm or less in consideration of the relationship with the diameter of the metal conductor 11 . Preferably, the insulating coating 12 is formed on the metal conductor 11 as a baking varnish coating. Since the baking varnish film is formed by repeating the continuous steps of coating and baking, the productivity is good, the adhesion with the metal conductor 11 is high, and the film strength can be further improved.

In addition, in this embodiment, the area|region which removes the predetermined length of the insulating film 12 from each edge part 16 of the metal conductor 11 is formed. The length of the region from which the insulating film 12 is removed can be appropriately set according to the structure of the probe unit 30 and the like.

(Example) In the following examples, as the metal conductor 11, a long and thin rhenium tungsten wire (outer diameter D: 0.025 mm) was used. The insulating film 12 has a two-layer structure, and the first insulating film is formed with a thickness of 1 μm using a urethane resin-based baking varnish paint as the paint for the first insulating film. For the second insulating coating, the same stoving varnish as the first insulating coating was used, and as the second insulating coating, 4 parts by weight of a pigment (manufactured by BASF Japan Ltd., trade name: Irgazin (registered trademark)) was used with respect to 100 parts by weight of the stoving varnish. The second insulating film was formed with a baking varnish paint for the insulating film with a thickness of 2.5 μm.

The slender contact probes formed with the insulating film 12 (total thickness of about 3.5 μm) are cut using a standard cutting machine, and the contact probes with the insulating film having a length of 10 mm are cut out, and the contact probes with the insulating film are cut out. A predetermined length of both ends of the probe is subjected to laser lift-off to produce a contact probe 10 having the aspect shown in FIG. 1 . When the metal conductor 11 is processed by the polishing device, the shape of the end portion 16 is adjusted by appropriately adjusting the polishing angle, time, and the like.

Then, on the surface of the metal conductor 11 exposed by peeling off the insulating film 12, a nickel plated layer with a thickness of 1 μm is provided by plating, and then a gold plated layer with a thickness of 0.2 μm is provided on the surface to form a total thickness of It is a plated layer of 1.2 μm.

5 shows the evaluation of the sliding of the end portion 16 relative to the inspection point 22 and the evaluation of the damage to the inspection point 22 in the case where the curvature radius R of the curved surface of the end portion 16 of the touch probe 10 of the above-mentioned embodiment is changed the result after. Furthermore, in this embodiment, the diameter D of the metal conductor 11 is constant. Furthermore, the case where the radius of curvature R of the end portion as Comparative Example 1 was 0.5D, the case where the end portion was flat as Comparative Example 2, and the case where the end portion was acute-angled as Comparative Example 3 were evaluated.

Incidentally, FIG. 6 shows an outline of the shape of the end portion of the contact probe 10 in the embodiment and the comparative example of FIG. 5 . In Fig. 6A, the end portion is a curved surface. In Fig. 6B, the end portion has a flat shape. In Fig. 6C, the end portion is an acute angle.

For the method of sliding evaluation, 10,000 contact tests were performed between the end portion 16 of the contact probe 10 and the object to be measured 20, and the evaluation A was used when the number of times of occurrence of sliding was 9 or less, and the number of times of occurrence of sliding was 10. When the number of times of slippage was more than 99 times, evaluation B was used, and when the number of times of slipping was 100 times or more, evaluation C was used.

In the damage evaluation method, the contact test was performed 10,000 times between the end portion 16 of the contact probe 10 and the object to be measured 20, and the evaluation A was used for the case of no damage, and the evaluation B was used for the case of damage.

Hereinafter, each Example will be described. For the end of Example 1, R=5D, and the corresponding model is shown in Figure 6A. The slip evaluation of Example 1 was A, and the damage evaluation was A.

For the end of Example 2, R=4D, and the corresponding model is shown in Figure 6A. The slip evaluation of Example 2 was A, and the damage evaluation was A.

For the end of Example 3, R=3D, the corresponding model is shown in FIG. 6A . The slip evaluation of Example 3 was A, and the damage evaluation was A.

For the end of Example 4, R=2D, the corresponding model is shown in Figure 6A. The slip evaluation of Example 4 was A, and the damage evaluation was A.

For the end of Example 5, R=1.5D, and the corresponding model is shown in Figure 6A. The slip evaluation of Example 5 was A, and the damage evaluation was A.

The end of Example 6, R=D, corresponds to the model shown in Figure 6A. The slip evaluation of Example 6 was A, and the damage evaluation was A.

For the end of Example 7, R=0.9D, and the corresponding model is shown in Figure 6A. The slip evaluation of Example 7 was B, and the damage evaluation was A.

For the end of Example 8, R=0.7D, and the corresponding model is shown in Figure 6A. The slip evaluation of Example 8 was B, and the damage evaluation was A.

Furthermore, the end portion of Comparative Example 1, R=0.5D, has the same shape as that of Examples 1 to 8, but the radius of curvature is formed to be larger than that of Examples 1 to 8. The slip evaluation of Comparative Example 1 was C, and the damage evaluation was A.

The end portion of Comparative Example 2 is a flat shape, and the corresponding model is shown in FIG. 6B . The slip evaluation of Comparative Example 2 was A, and the damage evaluation was B.

The end of Comparative Example 3 is an acute angle with a sharp front end, and the corresponding model is shown in FIG. 6C . The slip evaluation of Comparative Example 3 was A, and the damage evaluation was B.

5 , as in Comparative Example 1, it was found that the end of the contact probe 10 is a curved surface and the radius of curvature R is R≦0.5D, which is easy to slide, and the sliding evaluation deteriorates. In addition, if the end portion of the contact probe is in a flat shape as in Comparative Example 2, there is no problem in sliding evaluation, but damage occurs. In addition, if the end portion of the contact probe is at an acute angle as in Comparative Example 3, there is no problem in sliding evaluation, but damage occurs. Therefore, it can be found that when the end portion of the contact probe 10 is a curved surface and the radius of curvature R is 0.5D<R≦5D, it becomes difficult to slide and is not damaged, which is preferable.

In addition, both the sliding evaluation and the damage evaluation of Examples 1 to 6 were A. Therefore, as shown in Examples 1 to 6, it was also found that the range of R of D≦R≦5D is more excellent.

10: Contact Probe 11: Metal conductor 12: Insulating film 14: Main body 16: End 20: Object to be measured 22: Checkpoint 30: Probe unit 32: Upper board 34: Lower board 36: Support column 37: Leads

FIG. 1 is a schematic top view of a contact probe. FIG. 2 is an explanatory diagram showing a usage aspect of the contact probe. Figure 3 is an enlarged view of the end of the contact probe. FIG. 4 is an explanatory diagram showing a case where the ends of the contact probes are in contact with two inspection points. FIG. 5 is a table in which the results of the sliding test and the damage test were carried out by changing the shape of the end portion. 6A to 6C are explanatory diagrams showing the corresponding end shapes in the table of FIG. 5 .

16: End

D: the diameter of the metal conductor

R: radius of curvature

Claims (3)

A contact probe comprising: a main body part having an insulating coating on the outer periphery of a needle-shaped metal conductor; and an end part, which is formed on both ends of the metal conductor and does not have the insulating coating, by applying an insulating coating in an axial direction It is bent under load to obtain a contact pressure on the object to be measured, and electrical characteristics are measured. The contact probe is characterized in that the shape of at least one of the end portions on the side that is in contact with the object to be measured is a curved surface. When the radius of curvature of the curved surface is R and the diameter of the metal conductor is D, R is greater than 0.5D and 5D or less. The contact probe of claim 1, wherein the curvature radius R is greater than or equal to D. The contact probe according to claim 1 or 2, wherein the diameter of the metal conductor is 8 μm or more and 180 μm or less.

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