Patent Application
20180335447
This patent application is based on and claims priority from Japanese Patent Application No. 2017-097860 filed on May 17, 2017, the entire contents of which are incorporated herein by reference.
The present invention relates to a contact probe used for inspecting a measurement target device such as a semiconductor integrated circuit and an inspection jig including the contact probe.
JP-U-03-099364 discloses a contact probe including a tube and a plunger movable parallel with an axial direction of the tube.
In the structure of JP-U-03-099364, the plunger includes a small-diameter intermediate portion between a tip portion and a base portion. The small-diameter intermediate portion is required to have a length over a stroke length or more of the plunger. Thus, the small-diameter intermediate portion may become insufficient in strength, when the diameter of the plunger is reduced according to a diameter reduction of the contact probe. Furthermore, in the structure of JP-U-03-099364, since it is necessary to increase a thickness of a tip portion of the tube to which the plunger is to come into contact, a working operation of the tip portion of the tube would become difficult.
One or more embodiments relates to a contact probe that performs a scrub operation and an inspection jig that is equipped with the contact probe, in which a risk of strength reduction of a plunger would be lowered and a difficulty of a working operation of a tube would also be lowered.
In accordance with one or more embodiments, a contact probe includes a tube which is electrically conductive, a plunger which is electrically conductive and disposed in the tube at one end of the tube, and a spring which is disposed in the tube and urges the plunger in a projection direction. The tube includes a slant portion on an inner circumferential surface of the tube. The slant portion is inclined with respect to an axial direction of the tube. A base portion comes into contact with the slant portion and an inclination of the plunger varies, when the plunger retracts.
Other aspects and advantages of the invention will be apparent from the following description and the appended claims.
Embodiments will be hereinafter described in detail with reference to the drawings. Sets of the same or equivalent constituent elements, members, etc. shown in the drawings are given the same reference symbols and will not be described redundantly as appropriate. The embodiments are just examples and are not intended to restrict the invention, and features described in the embodiments and combinations thereof need not always be essential to the invention.
The contact probe 3 has a first plunger 10, a second plunger 20, a tube 30, and a spring 40. The first plunger 10 is a component for connection to an inspection target 8 shown in
The spring 40, which is a coil spring made of a common conductive metal material such as piano wire or stainless steel wire, urges the first plunger 10 and the second plunger 20 in such directions that they go away from each other and thereby gives them forces that cause them to come into contact with the inspection target 8 and the inspection board 9, respectively. The inspection target 8 is, for example, a semiconductor integrated circuit in which electrodes (in the illustrated example, electrode pads 8a) are arranged at prescribed intervals. The inspection board 9 has electrode pads 9a which are connected to a measuring instrument (not shown) and arranged at prescribed intervals.
The first plunger 10 has a tip-side cylinder portion 11 as a tip-side rod-shaped portion, a flange portion 12 as a drop-off-preventive large-diameter portion, and a base-side cylinder portion 13 as a base portion, which are arranged in this order from the tip side. The tip-side cylinder portion 11 penetrates through the small-diameter hole 6a of the first socket 6 and projects above the surface of the first socket 6. A tip portion of the tip-side cylinder portion 11 is a contact portion 11a which is tapered so as to assume a conical shape.
The flange portion 12 is larger in diameter than the tip-side cylinder portion 11 and housed in the tube 30. The outer diameter of the flange portion 12 is larger than the inner diameter of a narrowing portion 31 of the tube 30. Thus, the first plunger 10 is prevented from drop-off the tube 30 because of engagement between the flange portion 12 and the narrowing portion 31. The flange portion 12 is circular in a cross section taken perpendicularly to the longitudinal direction of the first plunger 10, and the outer diameter of the flange portion 12 is a little smaller than the inner diameter of the tube 30. The outer diameter and the width in the longitudinal direction of the first plunger 10 of the flange portion 12 are set so that as described later the first plunger 10 can be inclined with respect to the axial direction of the tube 30.
The base-side cylinder portion 13 is disposed inside the tube 30, is smaller in diameter than the flange portion 12, and is shaped like a cylinder that is approximately constant in diameter. When the first plunger 10 is inclined with respect to the axial direction of the tube 30 (stated roughly, the flange portion 12 serves as a supporting point), the bottom end of the outer circumferential surface of the base-side cylinder portion 13 comes into contact with the inner circumferential surface of the tube 30. Thus, the diameter and the length of the base-side cylinder portion 13 are set according to an inclination of the first plunger 10. The base surface of the base-side cylinder portion 13 is a flat surface that is perpendicular to the longitudinal direction of the first plunger 10, and is formed with a projection 13a. The projection 13a is fitted in the inner circumference of one end portion of the spring 40 and is thereby engaged with the spring 40. The first plunger 10 is inclined with respect to the axial direction of the tube 30 (described later).
The second plunger 20 has a tip-side cylinder portion 21 and a base-side cylinder portion 22, which are arranged in this order from the tip side. The tip-side cylinder portion 21 penetrates through and is guided by a small-diameter hole 7a of the second socket 7, and projects below the surface of the second socket 7. A tip portion of the tip-side cylinder portion 21 is a contact portion 21a which is tapered so as to assume a conical shape.
The base-side cylinder portion 22 is larger in diameter than the tip-side cylinder portion 21 and is housed in the tube 30. The outer diameter of the base-side cylinder portion 22 is larger than the inner diameter of a narrowing portion 32 of the tube 30. Thus, the second plunger 20 is prevented from drop-off the tube 30 because of engagement between the base-side cylinder portion 22 and the narrowing portion 32. The base surface of the base-side cylinder portion 22 is a flat surface that is perpendicular to the longitudinal direction of the second plunger 20, and is formed with a projection 22a. The projection 22a is engaged with the inner circumference of the other end portion of the spring 40.
The tube 30 is produced by forming narrowing portions 31-33 in a cylindrical metal pipe by known drawing. The portions, other than the narrowing portions 31-33, of the tube 30 have cylindrical shapes that are approximately constant in diameter. The tube 30 is set in the large-diameter hole 6b of the first socket 6 and the large-diameter hole 7b of the second socket 7. Since the outer diameter of the tube 30 is larger than the inner diameters of the small-diameter hole 6a of the first socket 6 and the small-diameter hole 7a of the second socket 7, the tube 30 is prevented from drop-off the socket 5.
The narrowing portion 31 is formed at the end, on the side of the first plunger 10, of the tube 30. The inner diameter of the narrowing portion 31 is larger than the diameter of the tip-side cylinder portion 11 of the first plunger 10 and smaller than the diameter of its flange portion 12, whereby as described above the first plunger 10 is prevented from drop-off the tube 30.
The narrowing portion 32 is formed at the end, on the side of the second plunger 20, of the tube 30. The inner diameter of the narrowing portion 32 is larger than the diameter of the tip-side cylinder portion 21 of the second plunger 20 and smaller than the diameter of its base-side cylinder portion 22, whereby as described above the second plunger 20 is prevented from drop-off the tube 30.
The narrowing portion 33 is, in this embodiment, a curved wall that is convex inward in the radial direction of the tube 30, and constitutes an intermediate portion (having a closed circumference), in the axial direction, of the tube 30. The inner circumferential surface of the narrowing portion 33 has a slant surface (slant portion) that is inclined so as to come closer to the center line as the position goes in the direction in which the base-side cylinder portion 13 of the first plunger 10 is inserted into the tube 30 (the axial direction of the tube 30).
The one end portion of the spring 40, which is disposed inside the tube 30, is engaged with the base surface of the base-side cylinder portion 13 and the projection 13a of the first plunger 10 and its other end portion is engaged with the base surface of the base-side cylinder portion 22 and the projection 22a of the second plunger 20. At least the end surface (seating surface), on the side of the first plunger 10, of the spring 40 being in a free state is inclined with respect to a plane that is perpendicular to the longitudinal direction of the spring 40. Thus, the spring 40 applies, to the base surface of the base-side cylinder portion 13 and the projection 13a of the first plunger 10, a force in such a direction as to incline the first plunger 10 with respect to the axial direction of the tube 30. The spring 40 extends spirally inside the tube 30.
A scrub operation (wipe operation) of the first plunger 10 will be described below.
To conduct an inspection using the inspection jig 1A, first, starting from the state of
In a process that the first plunger 10 retracts, the bottom end of the outer circumferential surface of the base-side cylinder portion 13 goes up onto the inner circumferential surface (i.e., the slant surface that is inclined with respect to the axial direction of the tube 30) of the narrowing portion 33 of the tube 30. As a result, the inclination of first plunger 10 with respect to the axial direction of the tube 30 decreases (i.e., the posture of the first plunger 10 becomes closer to a state that it is parallel with the axial direction of the tube 30). Since the outer diameter of the base-side cylinder portion 13 is a little smaller than the minimum inner diameter of the narrowing portion 33 of the tube 30, the first plunger 10 ends up being approximately parallel with the axial direction of the tube 30.
As the inclination of the first plunger 10 decreases, the position of the contact between the contact portion 11a of the tip-side cylinder portion 11 and the electrode pad 8a of the inspection target 8 deviates. This is a scrub operation which can increase the reliability of the contact by peeling off an oxide film, dirt, or the like formed on the surface of the electrode pad 8a. In
In all of the state of
Wear occurs between the outer circumferential surface of the base-side cylinder portion 13 and the inner circumferential surface of the cylindrical portion of the tube 30 and the inner circumferential surface of the narrowing portion 33 because of sliding contact. However, the degree of this wear is low because the difference between the outer diameter of the base-side cylinder portion 13 and the inner diameter of the cylindrical portion of the tube 30 and the difference between the outer diameter of the base-side cylinder portion 13 and the inner diameter of the narrowing portion 33 are smaller than the difference between the outer diameter of the tip-side cylinder portion 11 and the inner diameter of the small-diameter hole 6a of the first socket 6 and the difference between the outer diameter of the tip-side cylinder portion 11 and the inner diameter of the narrowing portion 31. The degree of wear between the outer circumferential surface of the flange portion 12 and the inner circumferential surface of the cylindrical portion of the tube 30 is likewise low.
This embodiment provides the following advantages:
(1) The inspection jig 1A is configured so that in a process that the first plunger 10 retracts being in contact with the electrode pad 8a of the inspection target 8, the base-side cylinder portion 13 comes into contact with (goes up onto) the slant surface of the inner circumferential surface of the tube 30 (i.e., the inner circumferential surface of the narrowing portion 33) and the inclination of the first plunger 10 with respect to the axial direction of the tube 30 thereby varies (decreases). Thus, it is not necessary to cause the outer circumferential surface of the tip-side cylinder portion 11 and the opening of the small-diameter hole 6a of the first socket 6 to slide on each other in a contact state. Likewise, it is not necessary to cause the outer circumferential surface of the tip-side cylinder portion 11 and the inner circumferential edge of the narrowing portion 31 of the tube 30 to slide on each other in a contact state. As a result, the degree of wear that occurs between the tip-side cylinder portion 11 and the first socket 6 and between the tip-side cylinder portion 11 and the inner circumferential edge of the narrowing portion 31 of the tube 30 due to a scrub operation would be made low. More specifically, damage of the opening of the small-diameter hole 6a of the first socket 6 due to sliding contact of the tip-side cylinder portion 11 to it is suppressed, and damage of the outer circumferential surface of the tip-side cylinder portion 11 due to its sliding contact to the inner circumferential edge of the narrowing portion 31 is also suppressed.
(2) To allow the first plunger 10 to perform a scrub operation, working needs to be performed on the original member of the tube 30 to form the narrowing portion 33. However, since this working may be known drawing, the working is less difficult than in the case of related art in which a tip portion of a tube is made thicker.
(3) A scrub length would be set irrespective of the stroke length of the first plunger 10 by changing the shape of the narrowing portion 33 of the tube 30. The degree of freedom of designing is thus high.
(4) Unlike in related art, it is not necessary to form a small-diameter portion in an intermediate portion of the first plunger 10 to enable a scrub operation. Thus, this embodiment is free of a problem of reduction in strength due to formation of a small-diameter portion in an intermediate portion.
Where as in the first embodiment the narrowing portion 33 of the tube 30 is inclined with respect to the axial direction of the tube 30 so as to assume a curve, the scrub length variation per unit stroke length in a stroke range of the first plunger 10 that is performing a scrub operation becomes shorter as the first plunger 10 retreats. In contrast, where as in this embodiment the narrowing portion 33 is inclined with respect to the axial direction of the tube 30 so as to extend straightly, the variation of the scrub length per unit stroke length in a stroke range of the first plunger 10 that is performing a scrub operation is small.
This embodiment is suitable for a case that it is desired to make gentler the scrub length variation at a start of a scrub operation. This embodiment would provide the same advantages as the first embodiment.
The inner circumferential surface of the non-slant portion 33b is parallel with the axial direction of the tube 30. In this embodiment, whereas a scrub operation occurs in that part of the stroke range of the first plunger 10 in which the base-side cylinder portion 13 goes up onto the inner circumferential surface of the slant portion 33a, no scrub operation occurs in that part of the stroke range of the first plunger 10 in which the base-side cylinder portion 13 is engaged with the inner circumferential surface of the non-slant portion 33b.
In the second half of the stroke range of the first plunger 10, the outer circumferential surface of the base-side cylinder portion 13 and the inner circumferential surface of the non-slant portion 33b are in contact with each other in such a manner as to be approximately parallel with each other, which suppresses the risk of local wear. This embodiment would provide the same advantages as the fifth embodiment.
As a result, in the first half of the stroke range of the first plunger 10, sliding contact occurs between the outer circumferential surface of the tip-side cylinder portion 11 and the opening of the small-diameter hole 6a of the first socket 6 and the opening of the small-diameter hole 6a suffers local wear.
In the second half of the stroke range of the first plunger 10, sliding contact occurs between the outer circumferential edge of the tip-side cylinder portion 11 and the inner circumferential edge of the narrowing portion 31 of the tube 30 and the outer circumferential surface of the tip-side cylinder portion 11 suffers local wear.
Although the invention has been described above using the embodiments, it would be understood by those skilled in the art that the constituent elements and the process employed in each embodiment may be modified in various manners without departing from the scope of the claims. Modifications will be described below.
The invention is not limited to the case that the slant portion of the inner circumferential surface of the tube 30 is formed in an intermediate portion of the tube 30 so as to have a closed circumference by drawing, for example: it may be formed as portions of the inner circumferential surface of an intermediate portion of the tube 30, for example, as at least three projections formed at equal intervals in the circumferential direction, by, for example, groove formation working on the outer circumferential surface.
For another example, a configuration is possible in which the second plunger 20 is omitted and the other end portion of the spring 40 is in contact with the electrode pad 9 of the inspection board 9.
In accordance with the embodiments, a contact probe includes a tube which is electrically conductive, a plunger which is electrically conductive and disposed in the tube at one end of the tube, and a spring which is disposed in the tube and urges the plunger in a projection direction. The tube includes a slant portion on an inner circumferential surface of the tube. The slant portion is inclined with respect to an axial direction of the tube. A base portion comes into contact with the slant portion and an inclination of the plunger varies, when the plunger retracts.
The contact probe may be such that in a state that the plunger is projected at the maximum, the base portion of the plunger is not in contact with the slant portion and the inclination of the plunger is large; and that when the plunger retracts and the base portion comes into contact with the slant portion, the inclination of the plunger becomes small.
The contact probe may be such that the plunger is equipped with a tip-side rod-shaped portion and a drop-off-preventive large-diameter portion which are arranged in this order from the tip side; and that the tip-side rod-shaped portion is not in contact with the one end of the tube in the whole of a stroke range of the plunger.
The contact probe may be such that the spring is a coil spring; and that a rear end portion of the base portion of the plunger is engaged with an inner circumferential surface of a tip portion of the coil spring.
The contact probe may be such that an intermediate segment is interposed between a tip portion of the spring and the base portion of the plunger; and that a force produced by resilience of the spring is applied to the base portion of the plunger via the intermediate segment.
According to embodiments, an inspection jig includes any of the above contact probes; and an electrically insulative socket which holds the contact probe that penetrates through the electrically insulative socket.
The inspection jig may be such that the plunger of the contact probe is equipped with a tip-side rod-shaped portion and a drop-off-preventive large-diameter portion which are arranged in this order from the tip side; and that the tip-side rod-shaped portion is not in contact with the socket in the whole of a stroke range of the plunger.
Any combinations of the above-described constituent elements and methods, systems, etc. obtained by converting any of the above expressions of the invention are also effective modes of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-097860 | May 2017 | JP | national |
