JP6841518B2 - Probe unit - Google Patents

Description

The present invention relates to a probe unit used for inspecting electrical characteristics of an object to be inspected (for example, a semiconductor device, a wafer, a circuit board, an integrated circuit, etc.).

Conventionally, as a contact probe used when inspecting the electrical characteristics of an object to be inspected (for example, a semiconductor device, a wafer, a circuit board, an integrated circuit, etc.), a thin plate having conductivity and spring property is used to form a contact portion and a deformed portion. There is known an electric contactor integrally formed with and (Patent Document 1).

Japanese Patent No. 5103566

By the way, the measured electric resistance value usually varies. This is because the surface of the metal is oxidized by air to form an oxide film.

Since the oxide film has a higher electrical resistance than the metal body, the correct resistance value to be inspected cannot be measured when the oxide film covers the surface of the metal body. Since the oxide film is naturally generated, the thickness of the oxide film is not uniform, and the measured resistance value varies.

If the variation in the measured resistance value increases, it is not possible to obtain an accurate inspection result of the object to be inspected. Therefore, in order to obtain accurate inspection results of the object to be inspected, it is indispensable to take measures to reduce the variation in the measured resistance value.

Here, a mode of measuring the resistance value using the conventional probe unit will be described.

FIG. 7 is a diagram showing the conventional probe unit 5, and FIG. 7A shows the state of the conventional probe unit 5 before the inspection. FIG. 7A shows the state of the conventional probe unit 5 at the time of inspection.

The conventional probe unit 5 includes a conventional contact probe 51 (hereinafter, simply referred to as a contact probe 51) and a housing 52 that houses the contact probe 11.

More specifically, the contact probe 11 has two conventional plungers 513 (hereinafter simply referred to as plungers 513) and a spring structure 515. The two plungers 513 are provided at both ends of the spring structure 515.

Further, the housing 52 is provided with a pin hole 521 that accommodates the contact probe 51 and projects the two plungers 513.

The inspection target 3 has a metal body 31 as an object to be inspected and an oxide film 32 adhering to the surface thereof. The inspection target 3 is a component or product in which a metal having electrical conductivity is used, for example, a semiconductor device, a circuit board, or the like.

As shown in FIG. 7A, in the conventional probe unit 5, when the inspection target 3 is pressed, the tip of the plunger 513 comes into contact with the oxide film 32, and then the central axis of the plunger 513 and the pin hole 521 It will sink vertically downward with the central axis almost aligned. As a result, the plunger 513 measures the resistance value of the metal body 31 via the oxide film 32, which makes the measurement with high accuracy difficult.

As a result of repeating trial and error in order to reduce the variation in the resistance value, the present inventor needs to scrape the oxide film generated on the metal surface to expose the metal body in order to reduce the variation in the measured resistance value. I thought there was.

The present invention has been made in view of the above points, and provides a probe unit capable of reducing the variation in the measured resistance value of the inspection target as much as possible by scraping the oxide film generated on the surface. The task is to do.

In order to solve the above problems, the present invention includes a contact probe having a plunger to be in contact with an inspection target, and a housing having a pin hole for projecting the plunger.
The plunger has a tip portion in contact with the inspection target, a small diameter portion formed to have a diameter smaller than the inner diameter of the pin hole, and a base end portion formed to have a diameter substantially the same as the inner diameter of the pin hole. And
The small diameter portion is provided between the tip portion and the base end portion.
The outer peripheral surface of the base end portion is formed to be curved outward in the radial direction of the pin hole.

With such a configuration, the oxide film generated on the surface to be inspected can be scraped off by the tip of the plunger. By scraping the oxide film, the resistance value of the metal body to be inspected that is not oxidized can be measured, and the variation in the measured resistance value can be reduced.

In a preferred embodiment of the present invention, the pin hole has a first accommodating portion in which the small diameter portion is accommodated and a second accommodating portion in which the base end portion is accommodated.
The inner diameter of the first accommodating portion is formed to be smaller than the inner diameter of the second accommodating portion.

With such a configuration, it is possible to prevent the plunger from jumping out of the housing during measurement.

A preferred embodiment of the present invention is characterized in that a large-diameter portion formed to have a diameter larger than the diameter of the small-diameter portion is provided on the tip end side of the small-diameter portion.

With such a configuration, the weight on the tip side of the plunger is increased, and the plunger is more likely to be tilted.

A preferred embodiment of the present invention is characterized in that a tapered portion whose diameter gradually increases toward the tip of the plunger is formed between the small diameter portion and the tip portion.

With such a configuration, it is possible to prevent accidental damage to the plunger. That is, if the tapered portion is not provided, a step is generated between the small diameter portion and the large diameter portion. Therefore, for example, when the contact probe is pressed too much during measurement, the angle of the step is formed. May come into contact with the housing and damage the plunger, but the formed tapered portion makes it possible to prevent such a situation.

According to the present invention, it is possible to provide a contact probe capable of reducing the variation in the measured resistance value of the inspection target as much as possible by scraping the oxide film generated on the surface.

It is a figure which shows the whole probe unit which concerns on embodiment of this invention. It is a partially enlarged view of the probe unit which concerns on embodiment of this invention. It is a figure which shows the state before the measurement which concerns on embodiment of this invention. It is a figure which shows the measurement mode using the probe unit which concerns on embodiment of this invention. It is a figure which shows the measurement mode using the probe unit which concerns on embodiment of this invention. It is a figure which shows the measurement mode using the probe unit which concerns on embodiment of this invention. It is a figure which shows the whole conventional probe unit.

Hereinafter, one of the embodiments of the present invention will be described with reference to the drawings.
The embodiments shown below are examples of the present invention, and the present invention is not limited to the following embodiments. Further, in these figures, reference numeral 1 indicates the probe unit 1 of the present embodiment.

As shown in FIG. 1A, the probe unit 1 includes a contact probe 11 and a housing 12 that houses the contact probe 11.

More specifically, the contact probe 11 has two plungers 113, 513 and a spring structure 115, as shown in FIG. 1 (a). The two plungers 113 and 513 are provided at both ends of the spring structure 115.

Further, as shown in FIG. 1 (c), the housing 12 is provided with pin holes 121 for accommodating the contact probe 11 and projecting the two plungers 113 and 513. The pin hole 121 contains a first accommodating portion 121a accommodating a small diameter portion 113d (see FIG. 2) of the plunger 113 and a second accommodating portion 113e (see FIG. 2) accommodating the spring structure 115 and the base end portion 113e of the plunger 113. A portion 121b and a portion 121b are formed.

FIG. 2 (a) is a partially enlarged view of the plunger 113, and FIGS. 2 (a) and 2 (c) are partially enlarged views of the probe unit 1.

As shown in FIG. 2A, the plunger 113 includes a tip portion 113a, a large diameter portion 113b, a tapered portion 113c whose diameter gradually increases toward the tip of the plunger, a small diameter portion 113d, and a base end portion. It has 113e and.

More specifically, the large diameter portion 113b, the tapered portion 113c, and the small diameter portion 113d are provided between the tip end portion 113a and the base end portion 113e. Further, the large diameter portion 113b is provided on the tip end portion 113a side, the small diameter portion 113d is provided on the base end portion 113e side, and the tapered portion 113c is provided between the large diameter portion 113b and the small diameter portion 113d. Further, the diameter of the large diameter portion 113b is formed to be larger than the diameter of the small diameter portion 113d.

As shown in FIG. 2A, the diameter of the small diameter portion 113d is formed to be smaller than the inner diameter of the first accommodating portion 121a.
In the present embodiment, the respective diameters are 0.78 mm for the small diameter portion 113d and 0.82 mm for the first accommodating portion 121a. The difference in diameter between the small diameter portion 113d and the first accommodating portion 121a is such that there is a swingable gap between the small diameter portion 113d and the first accommodating portion 121a with the center point O of the base end portion 113e as the base point. If so, you can set it freely.

The base end portion 113e is circular in a plan view. Further, as shown in FIG. 2A, the diameter of the base end portion 113e is configured to be substantially the same as the inner diameter of the second accommodating portion 121b of the housing 12. Further, the outer peripheral surface of the base end portion 113e is formed to be curved outward in the radial direction of the pin hole 121, and is formed so as to have a spherical shape obtained by dividing a regular sphere by two parallel planes as a whole. ing.

By doing so, the center point O of the base end portion 113e is fixed on the central axis of the pin hole 121. Then, the outer peripheral surface of the base end portion 113e is formed to be curved outward in the radial direction of the pin hole 121, so that the center point O of the base end portion 113e is formed as shown in FIG. 2 (c). As a base point, the contact position between the outer peripheral surface of the base end portion 113e and the inner wall of the second accommodating portion 121b changes smoothly, and the plunger 113 swings.

The outer peripheral surface of the base end portion 113e does not have to be spherical, and may be curved outward in the radial direction of the pin hole 121.
However, preferably, the R (radius of curvature) of the outer peripheral surface is an equal value from one end to the other end of the outer peripheral surface. That is, the center of the radius of curvature R of the outer peripheral surface is provided on the horizontal plane parallel to the radial direction of the pin hole 121 passing through the center point O of the base end portion 113e, and the distance from the center to the upper end and the lower end of the outer peripheral surface are provided. Make sure that the distance is the same. In this way, the plunger 113 can move smoothly without being caught when tilted.

Next, a measurement mode using the probe unit 1 will be described with reference to FIGS. 3 to 6.
In these figures, the axial direction of the pin hole 121 is configured to be perpendicular to the lower surface of the inspection target 3.

FIG. 3 is a diagram showing a probe unit 1 before contacting the inspection target 3.

The base 7 shown in FIG. 3A is made of a conductive material and is connected to an electronic device for analyzing resistance values (not shown). Further, the base 7 is brought into contact with the plunger 513, and the contact probe 11 pushed by the base 7 is pushed toward the opposite side of the base 7.

As shown in FIG. 3A, the plunger 113 protruding upward is slightly tilted even before it comes into contact with the inspection target 3. The straight line P is the central axis of the plunger 113, and the straight line C is the central axis of the pin hole 121.

Next, as shown in FIG. 4A, when the plunger 113 comes into contact with the inspection target 3 while the contact probe 11 is pushed out from the base 7, the inspection target 3 pushes the base 7 in the direction (arrow). The contact probe 11 is pushed back by a force facing W) (arrow X), and the spring structure 115 contracts (arrow Y). As a result, an urging force (arrow Z) acts on the spring structure 115.

At this time, since the extension operation of the spring structure 115 in the vertical direction is restricted by the inspection target 3, the plunger 113 has the center point O of the base end portion 113e due to the urging force of the spring structure 115. Is further tilted in the direction slightly tilted from the original, and the state shown in FIG. 5 is obtained.

FIG. 5 is a diagram showing a state in which the plunger 113 is in contact with and fixed to the inner wall of the pin hole 121.
More specifically, the plunger 113 is fixed by contacting and pressing against the inner wall of the pin hole 121 at points s and t. The point s is one point at the open end of the first accommodating portion 121a, and is a point where the small diameter portion 113d comes into contact. The point t is a point where the second accommodating portion 121b and the base end portion 113e come into contact with each other.

In this way, since the plunger 113 swings in a state where the tip portion 113a is in contact with the inspection target 3, the tip portion 113a scratches the oxide film 32 of the inspection target 3 to expose the metal body 31. Then, the tip portion 113a is pressed against the exposed metal body 31, and the measurement is performed in that state.

FIG. 6 illustrates the moving distance of the tip portion 113a.
The alternate long and short dash line Pa indicates the central axis of the plunger 113 in the state shown in FIG. 4, and the alternate long and short dash line Pb indicates the central axis of the plunger 113 in the state shown in FIG.

Here, the contact point between the tip portion 113a and the inspection target 3 at the moment of touching the inspection target 3 (oxide film 32) is set as a point a, and the tip when the oxide film 32 is scratched and the state shown in FIG. 6 is reached. Assuming that the contact point between the portion 113a and the inspection target 3 (metal body 31) is the point b, the horizontal linear distance between the point a and the point b is the moving distance D of the tip portion 113a.

The moving distance D is preferably in the range of 0, 1 mm to 0, 2 mm, but is not limited to this, and the variation in the measured resistance value can be reduced by scraping the oxide film 32. Any value may be used as long as the moving distance is D.
Further, in the present embodiment, the total length of the plunger 113 is 5.4 mm, the diameter of the small diameter portion 113d is 0.65 mm, the length of the small diameter portion 113d is 2 mm, the diameter of the large diameter portion 113b is 0.78 mm, and the diameter of the large diameter portion 113b. The length is 24 mm, the maximum diameter of the base end portion 113e is 0.98 mm, the inner diameter of the first accommodating portion 121a is 0.82 mm, the depth of the first accommodating portion 121a is 0.5 mm, and the inner diameter of the second accommodating portion 121b. Is designed to be 1 mm.

Table 1 is a scatter plot of the resistance values of the inspection target 3 when the probe unit 5 is used. Table 2 is a scatter plot of the resistance values of the inspection target 3 when the probe unit 1 is used.

As can be seen from Table 1, the variation in the measured resistance values is very large when the probe unit 5 is used, but as can be seen from Table 2, the variation in the measured resistance values is clear when the probe unit 1 is used. It is getting smaller. In Table 2, the proportional relationship between the load and the resistance value can also be seen.

According to this embodiment, the plunger 113 swings, and the oxide film 32 generated on the surface of the inspection target 3 can be scraped by the tip of the plunger 113. By scraping the oxide film 32, the resistance value of the metal body 31 of the inspection target 3 that has not been oxidized can be measured, and the variation in the measured resistance value can be reduced.

Further, since the inner diameter of the first accommodating portion 121a is formed to be smaller than the inner diameter of the second accommodating portion 121b, it is possible to prevent the plunger 113 from jumping out of the housing during measurement. It becomes.

Further, since the large diameter portion 113b formed to have a diameter larger than the diameter of the small diameter portion 113d is provided on the tip side of the small diameter portion 113d, the weight on the tip side increases and the plunger 113 is more easily tilted. Become.

Further, since the tapered portion 113c whose diameter gradually increases toward the tip of the plunger 113 is formed between the small diameter portion 113d and the tip portion 113a, it is possible to prevent the plunger 113 from being unexpectedly damaged. Become.

The various shapes, dimensions, and the like of each component shown in the above embodiment are examples, and can be variously changed based on design requirements and the like.

For example, the plunger 113 may not be provided with the large diameter portion 113b, but the tapered portion 113c may be lengthened so that the tip portion 113a is adjacent to the tapered portion 113c.

1 Probe unit 11 Contact probe 113 Plunger 113a Tip 113b Large diameter 113c Tapered 113d Small diameter 113e Base end 115, 515 Spring structure 12, 52 Housing 121, 521 Pin hole 121a First accommodating 121b Second accommodating Part 3 Inspection target 31 Metal body 32 Oxide film 5 Conventional probe unit 51 Conventional contact probe 513 Conventional plunger 7 Base D Movement distance O Center point P, Pa, Pb Center axis (plunger)
C center axis (pin hole)

Claims (4)

A contact probe having a plunger to be in contact with an inspection target and a housing having a pin hole for projecting the plunger are provided.
The plunger has a tip portion in contact with the inspection target, a small diameter portion formed to have a diameter smaller than the inner diameter of the pin hole, and a base end portion formed to have a diameter substantially the same as the inner diameter of the pin hole. And
The tip is formed in a rounded shape at the tip.
The small diameter portion is provided between the tip portion and the base end portion.
The outer peripheral surface of the proximal end, over the length entire axial length of the proximal portion, is formed to be curved at a substantially constant radius of curvature toward the radially outer side of the pin hole, and further, the It is configured so that it can contact the inner peripheral surface of the pin hole.
The axial length of the base end portion is longer than the distance along the radial direction between the open end edge portion of the pin hole and the outer peripheral surface of the small diameter portion . Probe unit. The pin hole has a first accommodating portion in which the small diameter portion is accommodated and a second accommodating portion in which the base end portion is accommodated.
The probe unit according to claim 1, wherein the inner diameter of the first accommodating portion is formed to be smaller than the inner diameter of the second accommodating portion. The probe unit according to claim 1 or 2, wherein a large diameter portion formed having a diameter larger than the diameter of the small diameter portion is provided on the tip end side of the small diameter portion. The probe according to any one of claims 1 to 3, wherein a tapered portion whose diameter gradually increases toward the tip of the plunger is formed between the small diameter portion and the tip portion. unit.