JP2015169518A - contact probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of a conventional probe that the plunger and barrel sliding area are in a definite area, and a contact resistance value tends to increase due to a flaw or metal scum, etc., on the sliding surface.SOLUTION: In a contact probe 1 according to the present invention, a spherical floating plunger 5 disposed inside a hollow part 2 of a plunger 2 is in a non-fixed state with respect to a coil spring 6. By using a coil spring 4 as the outer shape of the contact probe 1, the sliding distance is shortened, and the sliding area is hardly limited. As a result, a flaw, metal scum, etc., hardly occur on the definite sliding surfaces of at least plungers 2, 3, and a contact resistance value is stabilized, whereby the durability of the contact probe 1 is improved.

Description

  The present invention relates to a contact probe (probe unit), and more particularly to a structure that realizes a stable contact resistance value.

  As the structure of a conventional contact probe, the following structure is known.

  As shown in FIG. 6, the contact probe 31 has a structure in which a plunger 32 made of a rod-like body is inserted and held in a barrel 33 made of a tubular body. The plunger 32 is urged in the axial direction by a spring 34 (see FIG. 7A) in the barrel 33, and is movable in the axial direction.

  As shown in FIG. 7A, the barrel 33 has an inner diameter larger than the diameter of the plunger 32, and a bias pin 35 having one end fixed by the plunger 32 and the spring 34 is disposed in the barrel 33. Is done. The bias pin 35 is sandwiched between the plunger 32 and the spring 34 in the barrel 33 and can also move in the clearance direction indicated by the arrow 36.

  As shown in FIG. 7B, at the time of measurement, the bias pin 35 is pressed by the plunger 32 to form three conduction paths 36, 37, and 38 through the barrel 33 (for example, Patent Document 1). reference.).

JP 2006-90941 A (page 4-5, Fig. 1-3)

  However, in the contact probe 31, the conduction path 37, 38, 39 is formed by the plunger 32 moving in the barrel 33 in the axial direction and pressing the bias pin 35. Therefore, the distance that the plunger 32 and the bias pin 35 slide and move with the barrel 33 is also increased. By repeating this measurement operation, scratches such as metal peeling and metal debris are likely to occur in the sliding region of the barrel 33 and the sliding region of the bias pin 35, and the contact resistance value increases. .

  In particular, since one end of the bias pin 35 is fixed to the spring 34, the movable region of the bias pin 35 is limited, and the sliding region between the bias pin 35 and the barrel 33 tends to be a constant region. As a result, since the bias pin 35 and the barrel 33 repeatedly slide in a certain region, there is a problem that scratches such as metal peeling, metal debris, etc. are likely to occur, and durability is deteriorated. And since it is necessary to maintain desired quality (resistance value) in a measuring apparatus, the exchange cycle of a contact probe becomes short and there exists a problem which leads to a cost increase.

  In addition, with the recent high integration of semiconductor devices, a large number of contact probes 31 are brought into contact with the upper surface of the wafer, and a plurality of elements are inspected at once. The pitch between connection terminals provided in the element is narrowed year by year, and the contact probe 31 itself is required to be downsized.

  Further, the bias pin 35 makes point contact with the plunger 32, thereby realizing a structure in which the bias pin easily moves toward the inner peripheral surface side of the barrel 33. However, the point contact structure between the bias pin 35 and the plunger 32 has a problem that the contact resistance value tends to increase. Further, in the point contact state, a phenomenon called “instantaneous interruption” is likely to occur because the deflection of the barrel 33 (outer cylinder) is used. Then, although there is no abnormality in the semiconductor device to be inspected such as a wafer, it is determined as a defective product, and there is a possibility that the yield rate decreases due to erroneous measurement on the measuring device side.

  The present invention has been made in view of the circumstances described above, and the present invention includes a first plunger of a conductive cylindrical body having one end side serving as a first contact and the other end side serving as an open end, and one end. A second plunger that is a second contact, and at least a part of the other end is disposed in the first plunger and is movable in the axial direction of the first plunger, and one end The side is fixed to the outer peripheral surface of the first plunger, the other end side is fixed to the outer peripheral surface of the second plunger, and the first and second plungers are urged in the axial direction to expand and contract. A first spring, a second spring disposed in the first plunger and extending and contracting in the axial direction, the second spring being in a non-fixed state, and the second plunger Arranged movably within the first plunger between the second spring. And having a spherical conductive third plunger that.

  In the present invention, a spherical play body plunger and a coil spring are arranged in the plunger of the cylindrical housing, and a conduction path during measurement is formed. Since the play body plunger moves in the hollow portion of the plunger in a non-fixed state so as to be rotatable, duplication of sliding areas is reduced, and a low contact resistance value is maintained.

  Further, in the present invention, since the shape of the play body plunger is a spherical shape, the sliding area between the play body plunger and the plunger of the housing is reduced, and scratches such as metal peeling on the slide surface and metal The occurrence of debris and the like is greatly reduced, and high durability of the contact probe is realized.

  Moreover, in this invention, by using a spherical play body plunger, each plunger can contact stably and the phenomenon called "instantaneous interruption" can also be suppressed.

  Moreover, in this invention, an external shape is formed with the plunger of a cylindrical housing | casing, and the coil spring fixed to the outer peripheral surface. With this structure, the moving distance of the play body plunger inside the cylindrical housing is shortened, and the occurrence of scratches such as metal peeling on the sliding surface and metal debris can be greatly reduced.

  In the present invention, the coil spring is used as a part of the outer shape, and the contact probe is bent in the area of the coil spring and hardly bent in the area of the plunger. And it becomes easy to contact between each plunger stably. In addition, a phenomenon called “instantaneous interruption” that is likely to occur in the housing frame structure can be suppressed.

  Further, in the present invention, since the coil spring as a part of the outer diameter is not disposed inside the housing, the wire diameter can be selected according to the load load of the measuring apparatus, and the contact probe can be downsized.

  Moreover, in this invention, the material can be freely selected by not using the coil spring arrange | positioned in a plunger as a conductive path. And the elastic coefficient of a coil spring can be adjusted with materials other than a wire diameter, and it becomes easy to ensure the desired contact pressure to a play body plunger.

It is a side view for demonstrating the contact probe in embodiment of this invention. It is (A) sectional view, (B) sectional view, and (C) sectional view for explaining a contact probe in an embodiment of the invention. It is sectional drawing for demonstrating the contact probe in embodiment of this invention. It is a figure for demonstrating the result of the endurance test of (A)-(D) contact probe in embodiment of this invention. It is the schematic for demonstrating the measurement condition in embodiment of this invention. It is a side view for demonstrating the contact probe in conventional embodiment. It is (A) sectional drawing and (B) sectional drawing for demonstrating the contact probe in conventional embodiment.

  A contact probe according to an embodiment of the present invention will be described below.

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

  As shown in FIG. 1, the contact probe 1 is used, for example, in a measuring device that performs electrical characteristic inspections such as a semiconductor device for high frequency, an electronic component, and an electronic control circuit of an automobile. In recent years, with the high integration of semiconductor devices and the miniaturization of electronic components, it is necessary to bring the contact probe 1 into contact with the terminals and electrodes arranged at a fine pitch. Reduction of resistance value, stabilization, etc. are required.

  The contact probe 1 is mainly composed of a cylindrical plunger 2 in which contacts are formed, a plunger 3 in which contacts are formed, and a coil spring whose one end is fixed to the outer peripheral surfaces of both plungers 2 and 3. 4, a play body plunger 5 (see FIG. 2A) movably disposed in the plunger 2, and a coil spring 6 (see FIG. 2A) disposed in the plunger 2. Have The total length L of the contact probe 1 is about 18 mm, for example, and the outer diameter φ1 is about 0.8 mm, for example.

  The plunger 2 is formed, for example, as a cylindrical outer cylinder housing, a conical contact 2A is formed on one end side, and an open end 2B is formed on the other end side. Since the plunger 2 is used as a conductive path, for example, a copper material, a gold material, an alloy material or the like excellent in conductivity is used, and the inner peripheral surface on the hollow portion 2C (see FIG. 2A) side is also used. Gold plating, copper plating, Ni plating, etc. are formed in a single layer or laminated on the entire peripheral surface.

  Note that the shape of the contact 2A of the plunger 2 is not limited to a conical shape, and various shapes can be employed depending on the shape of the terminal or electrode with which the contact 2A is in contact. Moreover, although the case where 2 A of contactors were integrally shape | molded by the plunger 2 was demonstrated, it does not limit to this case. For example, the contact 2A may be formed as a separate body and then attached to one end of the plunger 2. Further, the cross-sectional shape of the plunger 2 is not limited to a circular shape, and the cross-sectional shape may be a polygon such as an octagon.

  The plunger 3 is formed as a cylindrical body having at least two types of outer diameters φ1 and φ2, for example. A conical contact 3 </ b> A is formed at the tip of one end of the plunger 3. On the other hand, a conical contact portion 3B (see FIG. 2A) is formed at the tip of the other end side of the plunger 3, and is disposed in the hollow portion 2C of the plunger 2. Since the plunger 3 is used as a conductive path, for example, a copper material, a gold material, an alloy material or the like excellent in conductivity is used, and the outer peripheral surface of the plunger 3 is gold plated, copper plated, Ni plated, or the like. Is formed as a single layer or a stacked layer.

  As with the plunger 2, the contact 3 </ b> A may be formed as a separate body and then attached to one end of the plunger 3.

  The coil spring 4 is fixed to the plunger 2 so that one end side winds the outer peripheral surface of the plunger 2, and is fixed to the plunger 3 so that the other end side winds the outer peripheral surface of the plunger 3. The coil spring 4 is wound closely at the portions fixed to the plungers 2 and 3 and is wound at a constant interval at the intermediate portion thereof, and according to the movement of the plunger 3 at the intermediate portion. It expands and contracts.

  And the coil spring 4 becomes a structure which is not accommodated in a housing | casing, It becomes possible to change the wire diameter of the coil spring 4 in a desired range according to the load applied from a measuring apparatus. The coil spring 4 may be a conductive material or a non-conductive material.

  The coil spring 4 also functions as the outer shape of the contact probe 1 and is stably planned using the end surfaces of the stepped portions of the plungers 2 and 3 indicated by circles 7 and 8 (see FIG. 2A). It is fixed to the jars 2 and 3.

  Next, FIG. 2A to FIG. 2C are cross-sectional views of the contact probe shown in FIG. 1 in the AA line direction. FIG. 2A shows the contact probe before applying a load. 2B and 2C show the state of the contact probe in the process of applying a load.

  FIG. 2A shows a situation in which, for example, the contact probe 1 is set in a measuring device (not shown), but no load is applied from the measuring device.

  First, the play body plunger 5 is formed as a spherical body, for example. The diameter φ3 (diameter) of the play body plunger 5 is, for example, 0.4 mm, the inner diameter φ4 of the plunger 2 is, for example, 0.5 mm, and the play body plunger 5 is a hollow portion of the plunger 2. It has a certain clearance with respect to the inner surface on the 2C side.

  The play body plunger 5 is not fixed to the coil spring 6, and the play body plunger 5 can move in the hollow portion 2 </ b> C between the plunger 3 and the coil spring 6.

  Further, since the play body plunger 5 is used as a conductive path, for example, a copper material, a gold material, an alloy material, or the like excellent in conductivity is used, and the outer peripheral surface of the play body plunger 5 is plated with gold or copper. Ni plating or the like is formed as a single layer or laminated.

  Although details will be described later, since the play body plunger 5 is a spherical body, it can freely rotate in any direction, and by increasing the number of measurements, the number of shallow scratches on the gold plating layer increases, but a certain area is Repeated contact is greatly reduced. And, the play body plunger 5 is prevented from being deeply damaged to increase the contact resistance value, and the play body plunger 5 itself is improved in durability.

  Since the coil spring 6 is not used as a conductive path, the coil spring 6 may be formed of an insulating material such as a metal material having low conductivity or plastic. The coil spring 6 is disposed in the hollow portion 2C of the plunger 2 so that its wire diameter is limited. However, since the material is not limited to the conductive material, the load load from the measuring device depends on the material. It can correspond to.

  One end side of the coil spring 6 is not fixed to the play body plunger 5 and is a free end, and the other end side is not fixed to the end portion in the hollow portion 2C of the plunger 2 and is a free end. The coil spring 6 is expanded or contracted in the axial direction by being pressed from the play body plunger 5 or tilted toward the inner peripheral surface of the plunger 2. When the contact probe 1 is assembled, the coil spring 6 and the play body plunger 5 are simply inserted sequentially into the hollow portion 2C of the plunger 2 and are arranged in an unfixed state.

  Next, as shown in the figure, the contact 2A of the contact probe 1 comes into contact with a terminal 9 such as a semiconductor element, and an electrical characteristic inspection is performed. In a state where no load is applied from the measuring device to the contact probe 1, the plunger 3 does not move in the axial direction, and no load is applied to the coil spring 4.

  Since the play body plunger 5 is not fixed to the coil spring 6, the play body plunger 5 is put on the coil spring 6 while leaning against the inner peripheral surface of the plunger 2. At this time, it becomes possible for the play body plunger 5 to lean on the inner peripheral surface of the plunger 2 on the entire circumference on one end side of the coil spring 6 due to mechanical vibration at the time of installation of the measuring device or preparation for measurement. . Moreover, the play body plunger 5 can be rotated on the coil spring 6 by utilizing the clearance with the inner peripheral surface of the plunger 2 due to the vibration or the like.

  The play body plunger 5 and the plunger 3 are separated from each other by a distance D1, and the push force from the plunger 3 is not applied to the play body plunger 5 while both the members 3 and 5 are separated.

  2 (B) and 2 (C) show a situation in which a load is applied to the contact probe 1 from the measuring device.

  As shown in FIG. 2B, the opening end 2B of the plunger 2 and the stopper 3C of the plunger 3 are separated by a distance D2 (see FIG. 2A). When a load is applied from the measuring device to the contact probe 1, the stopper portion 3 </ b> C of the plunger 3 moves toward the open end 2 </ b> B of the plunger 2.

  At this time, the plunger 3 is moved by the distance D1 (see FIG. 2A) and at least until the plunger 3 comes into contact with the play body plunger 5, the push force from the plunger 3 is applied to the play body plunger 5. Will not join.

  The distance D2 is set to 0.5 mm as the stroke distance of the contact probe 1, for example. The distance D1 is set to be shorter than the distance D2, so that the plunger 3 moves by a distance D1 or more so that the plungers 2, 3 and 5 are brought into contact with each other with a desired contact pressure, and the contact resistance value is increased. The reduced conductive paths 10 and 11 (see FIG. 2C) are ensured.

  As shown in FIG. 2 (C), when the plunger 3 is moved by the distance D1 or more, the play body plunger 5 is sandwiched between the plunger 3 and the coil spring 6, and the members 3 and 6 are substantially opposite to each other. The pressure is received. The plunger 3 is movable in the axial direction until the stopper portion 3C comes into contact with the opening end portion 2B of the plunger 2.

  At this time, since the play body plunger 5 is not fixed to the coil spring 6, the center of the play body plunger 5 and the axis of the coil spring 6 are difficult to coincide with each other, and the coil spring 6 contracts toward the inner peripheral surface side of the plunger 2. And lean. This state will be described later with reference to FIG.

  As a result, the play body plunger 5 receives a pressing force from the plunger 3 and the coil spring 6 and is fixed so as to be pressed against the inner peripheral surface of the plunger 2. Further, a part of the plunger 3 is fixed so as to be pressed against the inner peripheral surface of the plunger 2 by the reaction force from the play body plunger 5. Then, as indicated by the arrows, a first conductive path 10 formed by the plungers 2 and 3 and the play body plunger 5 and a second current path 11 formed by the plungers 2 and 3 are formed.

  As before, since the plunger 3 has a clearance with respect to the inner peripheral surface of the plunger 2 while moving the first distance D1, the plungers 2 and 3 do not slide substantially. . That is, it is after the plunger 3 has moved the distance D1 that the plungers 2, 3 and 5 slide. And by significantly reducing the sliding distance to which a large frictional force is applied, it is possible to significantly improve the increase in contact resistance due to scratches such as metal peeling or metal debris. Further, the durability of the contact probe 1 is greatly improved, the contact probe 1 has a longer life, the replacement cycle becomes longer, and the cost can be improved.

  Next, FIG. 3 is a cross-sectional view for explaining the contact state of each plunger and the conductive path.

  The state shown in FIG. 3 shows a state in which the play body plunger 5 is pressed by the plunger 3, and a state in which the state moves from FIG. 2 (B) to FIG. 2 (C). In this state, the center of the play body plunger 5 is located on the right side of the drawing with respect to the axis of the coil spring 6.

  Next, when the load from the measuring device is applied to the contact probe 1, as indicated by the arrow 12, the plunger 3 moves in the axial direction and presses the play body plunger 5 in the direction of the coil spring 6. To do. At this time, the play body plunger 5 has a spherical shape, and the play body plunger 5 makes point contact with the tip of the contact portion 3B of the plunger 3 in a state of leaning on the inner peripheral surface on the right side of the paper. And the play body plunger 5 presses the coil spring 6, but the play body plunger 5 presses the coil spring 6 in a state of leaning against the inner peripheral surface on the right side of the page, so that the coil spring 6 moves in the direction of the arrow 13. Shrink while tilting.

  In this state, the play body plunger 5 is pressed against the inner peripheral surface of the plunger 2 in the direction of the arrow 14 (right side of the drawing) by the pressing force from the plunger 3 and the coil spring 6. In the area indicated by the circle 15, the play body plunger 5 makes point contact with the inner peripheral surface of the plunger 2.

  On the other hand, the play body plunger 5 is in point contact with the contact portion 3B of the plunger 3 in the region indicated by the circle 16. And since the outer peripheral surface of the play body plunger 5 is a curved surface having a constant curvature and is easy to roll, the three members of the plunger 3, the play body plunger 5 and the coil spring 6 are most stably fixed. A state is created.

  That is, as indicated by the circles 15 and 16, the plungers 2, 3 and the play body plunger 5 are in point contact with each other, but the play body plunger 5 is in the above-described stable fixed state while rolling, The contact between the three parties is prevented from becoming a non-contact state, and a phenomenon called “instantaneous interruption” is also prevented.

  As a result, in the area where the play body plunger 5 and the contact portion 3B are in point contact and in the area where the play body plunger 5 and the inner peripheral surface of the plunger 2 are in point contact, the movement of the play body plunger 5 is caused. In addition, the repeated contact of a certain region is greatly reduced, and the occurrence of scratches such as metal peeling and metal debris due to repeated contact operations can be greatly reduced. Further, by preventing an increase in the contact resistance value between the plungers 2, 3, 5, the durability of the contact probe 1 is improved, and the contact probe 1 can be used repeatedly.

  Further, the coil spring 6 can have a structure in which the elastic coefficient is made small by the material and does not expand and contract so much. With this structure, as described above, the contact between the plungers 2, 3, 5 is a point contact, but the play body plunger 5 can receive a high contact pressure by the coil spring 6 and the plunger 3, The contact pressure between the plungers 2, 3, 5 is also increased. Then, a phenomenon called “instantaneous interruption” is prevented, and a stable contact resistance value of the contact probe 1 is realized.

  Further, since the contact portion 3B of the plunger 3 has a conical shape, when a load is applied, the center of the play body plunger 5 and the tip of the cone of the contact portion 3B are in a straight line parallel to the axial direction. 3, the play body plunger 5 reliably contacts with the inner peripheral surface of the plunger 2 as shown in FIG. 3, and a current path is secured.

  Finally, FIGS. 4A to 4D are diagrams for explaining the results of the contact probe durability test. FIG. 5 is a schematic diagram for explaining a measurement situation using a contact probe.

  The endurance test was set under the normal temperature condition by setting the stroke distance (D2) of the contact probe 1 to 0.5 mm, counting the reciprocating stroke once. Then, in the apparatus shown in FIG. 5, 400 pins of 20 vertical pins × 20 horizontal pins are arranged, and 10 pins are selected from them, and the test results are shown below. As described above, the contact portion 3B of the plunger 3 has a conical shape, and the play body plunger 5 has a spherical shape.

  As the initial values shown in FIG. 4A, the respective contact resistance values were in the range of 27 to 33 mΩ, and the respective contact loads were in the range of 33 to 39 gf.

  As the values at 50,000 times shown in FIG. 4B, the respective contact resistance values were in the range of 25 to 33 mΩ, and the respective contact loads were in the range of 30 to 38 gf.

  As values at 100,000 times shown in FIG. 4C, each contact resistance value was in the range of 24 to 34 mΩ, and each contact load was in the range of 31 to 36 gf.

  As a value at 400,000 times shown in FIG. 4D, each contact resistance value was in the range of 22 to 34 mΩ, and each contact load was in the range of 30 to 36 gf.

  From the test results shown in the figure, the contact resistance value is generally stable at about 30 mΩ, and the contact load is generally stable at about 35 gf, which proves the high durability of the contact probe 1.

  As shown in FIG. 5, in the measurement apparatus 21, a measurement object 22 such as a semiconductor wafer or an electronic circuit board is placed on a measurement table, and the number of contact probes 1 corresponding to the number of terminals of the measurement object 22 is connected to the socket 23. Deploy. Then, the load unit 24 of the measuring device 21 comes into contact with the contact 3A (see FIG. 1) of the contact probe 1, applies a load to all the contact probes 1 in the socket 23, and contacts 2A of the contact probe 1 (See FIG. 1) and the terminal are in sufficient contact, and an electrical characteristic inspection is performed. Depending on the measurement object 22, thousands to tens of thousands of contact probes 1 may be arranged in the socket 23. In order to apply a constant load to all the contact probes 1, it is necessary to increase the load applied from the load unit 24.

  As described above with reference to FIG. 1, the wire diameter of the coil spring 4 is changed within a desired range according to the load applied from the measuring device 21 by adopting a structure in which the coil spring 4 is not accommodated in the housing. Is possible. Even when the wire diameter of the coil spring 4 is increased, a housing that covers the periphery of the coil spring 4 is not required, so that the contact probe 1 can be reduced in size and can cope with recent miniaturized patterns.

  Further, the surface of the measurement object 22 on which the terminals and the like are formed has a large number of irregularities, and when a large number of contact probes 1 are arranged in the socket 23, the contact 2A is contacted with the terminals at the time of contact. Easy to be affected by unevenness.

  As described above with reference to FIGS. 2A to 2C, the contact spring 1 is bent in the region of the coil spring 4 and the plunger 2 is not easily bent by using the coil spring 4 as an outer frame. Is realized. In particular, when a large number of contact probes 1 are arranged in the socket 23, there are also a large number of contact probes 1 in which the open end 2B and the stopper 3C do not come into contact due to the influence of unevenness on the measured object 23 side such as terminals. However, a stable contact state between the plungers 2, 3, and 5 can be realized by the bent state of the coil spring 4. In addition, a phenomenon called “instantaneous interruption” that is likely to occur in the housing frame structure can be suppressed.

DESCRIPTION OF SYMBOLS 1 Contact probe 2 Plunger 2A Contact 2B Open end 2C Hollow part 3 Plunger 3A Contact 3B Contact 3C Stopper 4 Coil spring 5 Play body plunger 6 Coil spring 9 Terminal 10 Conductive path 11 Conductive path 21 Measuring device 22 Measurement Item 23 Socket 24 Load unit

Claims (4)

A first plunger of a conductive cylindrical body having one end side as a first contact and the other end side as an open end;
A second plunger having one end side serving as a second contact, at least a part of the other end side being disposed in the first plunger, and movable in an axial direction of the first plunger;
One end side is fixed to the outer peripheral surface of the first plunger, the other end side is fixed to the outer peripheral surface of the second plunger, and the first and second plungers are urged in the axial direction. A first spring that expands and contracts;
A second spring disposed in the first plunger and extending and contracting in the axial direction;
A spherical conductive third that is in a non-fixed state with the second spring and is movably disposed in the first plunger between the second plunger and the second spring. A contact probe.   The said 2nd plunger has a stopper part which contact | abuts the opening edge part of a said 1st plunger, and stops the movement to the said axial direction of a said 1st plunger. Contact probe according to.   The contact probe according to claim 1 or 2, wherein the other end side of the second plunger has a conical shape.   4. The measurement device according to claim 3, wherein at the time of measurement, the third plunger comes into contact with the first plunger by a pressing force from the second plunger and a pressing force from the second spring. Contact probe.

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