JP7450574B2 - Contact probe and electrical property measurement method - Google Patents

Description

The present disclosure relates to a contact probe and a method for measuring electrical characteristics using the same.

Conventionally, electrical characteristics of power semiconductor devices are often measured by bringing a contact probe into contact with a flat electrode terminal.

However, oxidation of the surface of the electrode terminal and stress during molding such as bending of the electrode terminal cause variations in the flatness of the surface of the electrode terminal, resulting in a small contact area between the contact probe and the electrode terminal. Therefore, when a large current is passed from the contact probe to the electrode terminal, heat generation such as Joule heat may cause the contact probe to weld to the electrode terminal or increase contact resistance, which may change the measured value and prevent normal measurement. Ta.

For example, in Patent Document 1, in a probe formed on a substrate, at least a part of the middle portion is curved in a bellows shape and contacts an electrode (corresponding to an electrode terminal) of the specimen, and a bridge portion whose both ends are fixed to the substrate. A structure having the following is disclosed. By bringing the bridge portion into contact with the electrode, a large load can be applied to the electrode, thereby increasing the reliability of electrically connecting the bridge portion and the electrode.

Japanese Patent Application Publication No. 2005-37199

However, although the technology described in Patent Document 1 improves the reliability of electrically connecting the bridge part and the electrode, the bridge part and the electrode contact at one place, so the electrode can come into contact with the contact probe. This was insufficient to obtain a stable contact state when the surface area was small.

Therefore, an object of the present disclosure is to provide a technique that can obtain a stable contact state between a contact probe and an electrode terminal even when the contactable area of the electrode terminal with respect to the contact probe is small.

A contact probe according to the present disclosure is a contact probe that contacts an electrode terminal of an object to be measured, and includes a base formed of a linear conductor having spring properties, and a base formed on the base and connected to the electrode terminal. a plurality of contact portions having an Ω-shape that protrudes toward the electrode terminal so as to be able to make contact at a plurality of locations; and a holding surface that holds both longitudinal ends of the base; a pair of holders that are pressurized to contact the electrode terminals , both longitudinal ends of the base have a hemispherical convex shape, and the holding surfaces of the pair of holders have a hemispherical concave shape. , both longitudinal ends of the base and the holding surfaces of the pair of holders have the same curvature.

According to the present disclosure, since the contact probe having spring properties contacts the electrode terminal at multiple locations, the contact probe and the electrode terminal can maintain a stable contact state even when the contactable area of the electrode terminal with respect to the contact probe is small. can be obtained.

FIG. 3 is a front view showing a state in which the contact probe according to the first embodiment is arranged above the electrode terminal (in the Z direction). FIG. 3 is a front view showing a base portion and a contact portion included in the contact probe according to the first embodiment. 3 is a sectional view taken along line AA in FIG. 2. FIG. FIG. 3 is a front view showing a state in which the contact probe according to the first embodiment is in contact with an electrode terminal. FIG. 3 is a top view showing a state in which the contact probe according to the first embodiment is in contact with an electrode terminal. FIG. 7 is a top view showing a state in which a plurality of contact probes are brought into contact with electrode terminals in Embodiment 2; 7 is a top view showing a state in which a plurality of contact probes 2 are brought into contact with an electrode terminal 1 in a modification of the second embodiment. FIG.

<Embodiment 1>
Embodiment 1 will be described below using the drawings. FIG. 1 is a front view showing a state in which a contact probe according to Embodiment 1 is arranged above an electrode terminal (in the Z direction). FIG. 2 is a front view showing a base and a contact portion of the contact probe. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2.

In FIG. 1, the X direction, Y direction, and Z direction are orthogonal to each other. The X, Y, and Z directions shown in the figures below are also orthogonal to each other. In the following, a direction including the X direction and the direction opposite to the X direction (-X direction) will also be referred to as the "X-axis direction." Furthermore, hereinafter, a direction including the Y direction and the direction opposite to the Y direction (-Y direction) will also be referred to as the "Y-axis direction." Further, hereinafter, a direction including the Z direction and the direction opposite to the Z direction (-Z direction) will also be referred to as the "Z-axis direction."

As shown in FIG. 1, the contact probe 2 is provided in an evaluation device that evaluates a plurality of semiconductor devices (not shown) used in semiconductor elements (not shown). The evaluation device measures the electrical characteristics of the semiconductor device by bringing the contact probe 2 into contact with the electrode terminal 1 of the semiconductor device, which is the object to be measured, and energizing the contact probe 2 and the electrode terminal 1.

As shown in FIG. 1, the contact probe 2 includes a base 3, a plurality (for example, two) of contact parts 4, and a pair of holders 5. The base 3 is made of, for example, a conductor punched out of a copper alloy such as beryllium copper having a thickness of 0.3 mm or more and 1.2 mm or less. That is, the base 3 is made of a linear conductor having spring properties.

As shown in FIGS. 1 and 2, each contact portion 4 is formed in the middle of the base 3 and has an Ω-shape that protrudes toward the electrode terminal 1 so that it can contact the surface of the electrode terminal 1. have. That is, the plurality of contact portions 4 are also constituted by linear conductors having spring properties. Here, an oxide film is formed on the surfaces of the base portion 3 and the plurality of contact portions 4.

The number of contact points between the contact probe 2 and the electrode terminal 1 is determined according to the number of contact parts 4. Note that the number of contact portions 4 is not limited to two, and three or more may be provided.

Each contact portion 4 includes an arcuate tip portion 4 a that is a portion that contacts the electrode terminal 1 , and a connecting portion 4 b that connects the tip portion 4 a and the base portion 3 . As shown in FIG. 3, the cross-sectional shape of the tip 4a of each contact portion 4 has a V-shaped groove 4c and flat surfaces 4d formed on both sides of the V-shaped groove 4c. Oxidation of the surface of the electrode terminal 1 and stress during molding such as bending of the electrode terminal 1 cause variations in the flatness of the surface of the electrode terminal 1, but in each contact portion 4, two flat surfaces 4d are It comes into contact with a highly flat part of the terminal 1.

Here, both sides of the V-shaped groove 4c are the outer sides of the V-shaped groove 4c. Note that the V-shaped groove 4c may be formed over the entire area of the tip portion 4a, or may be formed only in the portion that contacts the electrode terminal 1.

As shown in FIG. 1, the pair of holders 5 are made of metal, for example, and hold a base 3 provided with a plurality of contact parts 4, and are connected to a moving mechanism of an evaluation device (not shown). The pair of holders 5 are moved in the vertical direction (Z-axis direction) by a moving mechanism, so that the base 3 and the plurality of contact parts 4 are positioned above the electrode terminal 1 (in the Z direction), and the plurality of contact parts 4 are moved in the vertical direction (Z-axis direction). and the position where it contacts the electrode terminal 1. Holding surfaces 5a that hold both longitudinal ends of the base 3 are formed in the pair of holders 5 at positions facing both longitudinal ends of the base 3.

Both longitudinal ends of the base 3 have a hemispherical convex shape, while the holding surfaces 5a of the pair of holders 5 have a hemispherical concave shape. Both longitudinal ends of the base 3 and the holding surfaces 5a of the pair of holders 5 have the same curvature. By forming both longitudinal ends of the base 3 and the holding surfaces 5a of the pair of holders 5 into such shapes, both longitudinal ends of the base 3 become difficult to slide against the holding surfaces 5a of the pair of holders 5.

FIG. 4 is a front view showing a state in which the contact probe 2 is in contact with the electrode terminal 1. As shown in FIG. 4, when the tip portions 4a of the plurality of contact portions 4 are pressed against the electrode terminal 1 during electrical characteristic measurement, the Ω-shaped shape of the contact portions 4 is elastically deformed, and both longitudinal ends of the base portion 3 are Although an attempt is made to slide the holding surfaces 5a of the pair of holders 5, since the sliding amount of both longitudinal ends of the base 3 with respect to the holding surfaces 5a of the pair of holders 5 is suppressed, both longitudinal ends of the base 3 and the pair of holders 5 and the holding surface 5a can be significantly suppressed.

Next, the functions and effects of the contact probe 2 according to the first embodiment will be explained using FIGS. 4 and 5. FIG. 5 is a top view showing a state in which the contact probe 2 is in contact with the electrode terminal 1.

As shown in FIGS. 4 and 5, the evaluation device moves the base 3 and the plurality of contact parts 4 from a position above the electrode terminal 1 (in the Z direction) to a position where it contacts the electrode terminal 1 via a pair of holders 5. After moving the contact parts 4 to the electrode terminal 1, the plurality of contact parts 4 are further pressed against the electrode terminal 1 to press the tips 4a of the plurality of contact parts 4 to the electrode terminal 1, thereby elastically deforming the Ω-shaped shapes of the plurality of contact parts 4. .

Due to the elastic deformation of the plurality of contact parts 4, an appropriate load is applied from the plurality of contact parts 4 to the electrode terminal 1, and the plurality of contact parts 4 are brought into contact with the electrode terminal 1 with an appropriate load. The oxide film formed at the contact portion 4 in contact with the electrode terminal 1 is destroyed. This reduces the contact resistance between the plurality of contact parts 4 and the electrode terminal 1, making it possible to flow a large current.

In particular, when the surface of the electrode terminal 1 has a high degree of flatness, the contact probe 2 and the electrode terminal 1 make contact at a maximum of four locations in total, making it possible to obtain a low contact resistance value of about 0.1 mΩ or more and 3 mΩ or less. , it becomes possible to flow a large current of approximately 50 A/ms or more and 250 A/ms or less per contact probe 2.

As described above, in the first embodiment, the contact probe 2 includes a base 3 made of a linear conductor having spring properties, and a contact probe 2 formed on the base 3 and capable of contacting the electrode terminal 1 at multiple locations. A plurality of contact portions 4 having an Ω-shape projecting toward the electrode terminal 1 are provided.

Therefore, since the contact probe 2 having spring properties contacts the electrode terminal 1 at a plurality of locations, a stable contact state can be obtained even when the contactable area of the electrode terminal 1 with respect to the contact probe 2 is small.

Further, the cross-sectional shape of the tip portion 4a of each contact portion 4 includes a V-shaped groove 4c and flat surfaces 4d formed on both sides of the V-shaped groove 4c. Therefore, since each contact portion 4 can contact the electrode terminal 1 at two flat surfaces 4d, even if the contact area of the electrode terminal 1 to the contact probe 2 is small, the contact probe 2 and the electrode A contact area with the terminal 1 can be secured.

Further, the surface of the electrode terminal 1 may be warped due to the structure of the semiconductor device. Even in such a case, since the cross-sectional shape of the tip portion 4a of each contact portion 4 has a V-shaped groove 4c and two flat surfaces 4d, a part of the V-shaped groove 4c comes into contact with the electrode terminal 1, etc. Thus, a contact area between the contact probe 2 and the electrode terminal 1 can be secured.

The contact probe 2 further includes a pair of holders 5 that have holding surfaces 5a that hold both ends of the base 3 in the longitudinal direction, and that pressurize the plurality of contact parts 4 so as to bring them into contact with the electrode terminals 1. . Therefore, since the plurality of contact parts 4 can be brought into contact with the electrode terminal 1 while the base part 3 is held by the pair of holders 5, the plurality of contact parts 4 can be brought into contact with the electrode terminal 1 in a stable state. .

Further, both longitudinal ends of the base 3 have a hemispherical convex shape, the holding surfaces 5a of the pair of holders 5 have a hemispherical concave shape, and both longitudinal ends of the base 3 and the holding surfaces of the pair of holders 5 5a have the same curvature.

Therefore, both longitudinal ends of the base 3 become difficult to slide against the holding surfaces 5a of the pair of holders 5, thereby suppressing wear between both longitudinal ends of the base 3 and the holding surfaces 5a of the pair of holders 5. Therefore, the durability of the contact probe 2 is improved. Thereby, it is possible to reduce the running cost associated with measuring electrical characteristics.

<Embodiment 2>
Next, a contact probe 2 according to a second embodiment will be explained. FIG. 6 is a top view showing a state in which a plurality of contact probes 2 are brought into contact with electrode terminals 1 in the second embodiment. FIG. 7 is a top view showing a state in which a plurality of contact probes 2 are brought into contact with the electrode terminal 1 in a modification of the second embodiment. In addition, in the second embodiment, the same components as those explained in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

In the first embodiment, one contact probe 2 is arranged, and one contact probe 2 and the electrode terminal 1 are energized.

On the other hand, in Embodiment 2, in order to further increase the contact area between the contact probes 2 and the electrode terminals 1, as shown in FIG. The contact probes 2 and the electrode terminals 1 are energized. Further, a pair of holders 5 of adjacent contact probes 2 are arranged in contact with each other.

Note that the number of contact probes 2 is not limited to eight, and two or more contact probes 2 may be arranged.

As described above, in the second embodiment, the electrical characteristic measuring method measures the electrical characteristics of a semiconductor device by arranging a plurality of contact probes 2 and energizing the plurality of contact probes 2 and the electrode terminal 1. are doing.

Therefore, since the contact area between the contact probe 2 and the electrode terminal 1 can be further increased, it is possible to measure electrical characteristics with a large current required for semiconductor devices. Furthermore, since the contact probes 2 can be replaced individually, it is possible to reduce the running cost associated with measuring electrical characteristics.

Further, as shown in FIG. 7, one contact probe 2 among the plurality of contact probes 2 may be configured to function as a sensing contact probe 12. The pair of holders 5 included in the sense contact probe 12 have the same shape as the pair of holders 5 included in the contact probe 2, but are holders corresponding to the electrically insulated sense contact probe 12. Furthermore, the pair of holders 5 included in the sensing contact probe 12 are located apart from the pair of holders 5 included in the adjacent contact probes 2 .

As described above, in the modification of the second embodiment, one contact probe 2 among the plurality of contact probes 2 functions as the sense contact probe 12. Therefore, by bringing the sense contact probe 12 into contact with the electrode terminal 1, a Kelvin connection can be easily made, and therefore, it is possible to perform even more accurate measurement.

Note that it is possible to freely combine each embodiment, or to modify or omit each embodiment as appropriate.

1 Electrode terminal, 2 Contact probe, 3 Base, 4 Contact part, 4c V-shaped groove, 4d Flat surface, 5 Holder, 5a Holding surface, 12 Sense contact probe.

Claims (4)

A contact probe that contacts an electrode terminal of an object to be measured,
a base made of a linear conductor having spring properties;
a plurality of contact portions formed on the base portion and having an Ω-shape that protrudes toward the electrode terminal so as to be able to contact the electrode terminal at multiple locations ;
a pair of holders that have holding surfaces that hold both longitudinal ends of the base and that pressurize the plurality of contact portions so as to contact the electrode terminals ;
Both longitudinal ends of the base have a hemispherical convex shape,
The holding surfaces of the pair of holders have a hemispherical concave shape,
A contact probe , wherein both longitudinal ends of the base and the holding surfaces of the pair of holders have the same curvature . 2. The contact probe according to claim 1, wherein a cross-sectional shape of a tip end of each of the contact portions has a V-shaped groove and flat surfaces formed on both sides of the V-shaped groove. An electrical property measuring method using the contact probe according to claim 1 or 2 , comprising:
An electrical property measuring method comprising arranging a plurality of the contact probes and energizing the plurality of contact probes and the electrode terminals to measure the electrical properties of the object to be measured. 4. The electrical characteristic measuring method according to claim 3 , wherein one of the plurality of contact probes functions as a sense contact probe.

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