Probe pin for electric characteristic inspection and probe card

Abstract

This probe pin (10) for electric characteristic inspection has a pin body (12) containing a conductive material. The shape of a cross section of the pin body (12) in a direction orthogonal to the length direction is a trapezoidal shape in which the length of the upper base and the length of the lower base are different.

Description

Probe pin for electrical property inspection and probe card

[0001] The present invention relates to a probe pin for electrical property inspection and a probe card.

[0002] In recent years, along with the miniaturization of electronic devices, high-density mounting of various circuit boards used therein has been demanded. On the other hand, for various circuit boards such as various mounting boards and IC package boards, it is common to perform various electrical property inspections such as DC resistance measurement and continuity inspection during manufacturing. Such electrical property inspections are usually often performed using a probe card including a probe for contacting an electrode of a circuit board and an inspection device for measuring a resistance value or the like via the probe card (see, for example, Patent Document 1).

[0003] Patent Document 1 describes a probe card including a first guide plate having a plurality of first guide holes formed therein, a second guide plate having a plurality of second guide holes formed therein, and a probe having a rectangular cross-sectional shape in a direction orthogonal to the length direction. One end of the probe is inserted into the first guide hole, and the other end is inserted into the second guide hole. The first guide plate and the second guide plate are arranged offset in the planar direction such that the first guide holes and the second guide holes do not align with each other. The probe fixed to the first guide plate and the second guide plate is arranged in a curved shape. In the probe card, when the probe is brought into contact with an object to be inspected, the probe is further deformed, thereby absorbing the force that the probe receives from the object to be inspected.

[0004] Japanese Unexamined Patent Publication No. 2024-174199

[0005] However, in the probe card described in Patent Document 1, since the cross-sectional shape of the probe is rectangular, there is a risk that each probe may curve and contact in different directions, and there is room for study as to whether the probe can be appropriately deformed.

[0006] A main object of the present invention is to provide a probe pin for electrical property inspection that can be appropriately deformed, and a probe card including the probe pin for electrical property inspection.

[0007] To solve the above problems, according to one aspect of the present invention, there is a probe pin for electrical characteristic testing having a pin body containing a conductive material, characterized in that the cross-sectional shape in a direction perpendicular to the longitudinal direction of the pin body is a trapezoidal shape with different lengths for the upper and lower bases.

[0008] To solve the above problems, according to one aspect of the present invention, a probe card is provided comprising: a first plate having a plurality of first through holes; a second plate spaced apart from the first plate and having a plurality of second through holes; and a plurality of probe pins for electrical characteristic testing of the present invention, one end of which is inserted into the first through hole and the other end of which is inserted into the second through hole corresponding to the first through hole.

[0009] According to the present invention, it is possible to provide a probe pin for electrical characteristic testing that can be appropriately deformed, and a probe card including the probe pin for electrical characteristic testing.

[0010] Figures 1A and 1B show the configuration of probe pins for electrical characteristic testing. Figure 2 shows a partial configuration of a probe card for testing the electrical characteristics of an object under test. Figures 3A and 3B illustrate the arrangement of probe pins for electrical characteristic testing on the probe card. Figures 4A and 4B illustrate the effects of the present invention.

[0011] The following describes a probe pin for electrical characteristic testing (hereinafter also simply referred to as "probe pin") and a probe card according to one embodiment of the present invention. However, the probe pin and probe card for electrical characteristic testing of the present invention are not limited to the embodiments shown below. In this specification, the "~" indicating a numerical range includes both an upper and lower limit.

[0012] (Configuration of probe pins for electrical characteristic testing) Figure 1A is a plan view of the probe pin 10 for electrical characteristic testing, and Figure 1B is a cross-sectional view taken along line A-A shown in Figure 1A.

[0013] The probe pin 10 for electrical characteristic testing includes a pin body 12. As shown in Figures 1A and 1B, the probe pin 10 according to this embodiment has a plating layer 13 and an insulating coating 14 in addition to the pin body 12.

[0014] The pin body 12 contains a conductive material. The conductive material is not particularly limited as long as it is conductive. A copper alloy is preferred as the conductive material. The copper alloy contains silver, with the remainder being copper and unavoidable impurities. Examples of unavoidable impurities include tin, beryllium, zinc, nickel, magnesium, aluminum, titanium, zirconium, indium, silicon, and phosphorus. There may be one type of unavoidable impurity or two or more types. The silver content is appropriately selected according to the desired properties of the probe pin (pin body), but is preferably in the range of 6.0 to 30.0 mass%, and more preferably in the range of 10.0 to 25.0 mass%. If the silver content is less than 6.0 mass%, the hardness of the probe pin 10 cannot be made within the desired range. On the other hand, if the silver content exceeds 30.0 mass%, the effect commensurate with the cost of adding silver cannot be obtained.

[0015] The cross-sectional shape of the pin body 12 in a direction perpendicular to its length is a trapezoidal shape in which the length of the upper base a and the length of the lower base b are different. Here, a trapezoid is a shape in which only one of two opposite sides (upper base a and lower base b) are parallel. The trapezoidal shape in which the length of the upper base a and the length of the lower base b are different may be a true trapezoid or a trapezoidal shape with rounded corners. The thickness of the pin body 12 is preferably in the range of 0.001 to 0.200 mm. When the cross-sectional shape of the pin body 12 is a trapezoidal shape in which the length of the upper base a and the length of the lower base b are different, the thickness of the pin body 12 corresponds to the height h of the trapezoid. The width of the pin body 12 is also preferably in the range of 0.001 to 0.200 mm. The width of the pin body 12 refers to the longer length of either the upper base a or the lower base b in the direction perpendicular to the height h of the trapezoid. The length in the height direction of the trapezoid is preferably shorter than the width direction perpendicular to the height direction. Specifically, the ratio of the width of the pin body 12 to the thickness is preferably in the range of over 100% and 300% or less, and more preferably in the range of over 100% and 150% or less. The ratio of the length of the upper base a to the length of the lower base b in the trapezoid is not particularly limited. The ratio of the length of the upper base a to the length of the lower base b in the trapezoid is preferably in the range of 60% or more and less than 100%. Here, the upper base a is the shorter side of the base. The lower base b is the side opposite the upper base a.

[0016] The overall shape of the pin body 12 is that its cross-section is trapezoidal from one end to the other. Preferably, the pin body 12 has an upper base a and a lower base b that are located on the same side from one end to the other. In other words, it is preferable that the shape of the pin body 12 in this embodiment is not twisted with respect to the axis along the length direction of the pin body 12. The lengths of the upper base a and the lower base b may be the same from one end to the other of the pin body 12, or they may be partially different in length, as long as the upper base a and the lower base b are located on the same side. Also, the cross-sectional shape of the pin body 12 may be a different trapezoidal shape from one end to the other, or it may be a similar trapezoidal shape. In this embodiment, the lengths of the upper base a and the lower base b are the same from one end to the other of the pin body 12. In other words, in this embodiment, the shape of any cross-section from one end to the other of the pin body 12 is the same trapezoidal shape.

[0017] The method for manufacturing the pin body 12 is not particularly limited. Examples of methods for manufacturing the pin body 12 include rolling a copper alloy wire so that its cross-sectional shape is trapezoidal, passing a copper alloy wire through a die having a trapezoidal through-hole, etching a copper alloy foil, and laser processing a copper alloy foil.

[0018] The plating layer 13 covers the pin body 12. The metals included in the plating layer 13 are gold, nickel, rhodium, palladium, etc. The method for forming the plating layer 13 is not particularly limited. Examples of methods for forming the plating layer 13 include electroplating and hot-dip plating. The plating layer 13 may be a single layer or multiple layers. The plating layer 13 may be placed only on both ends of the pin body 12, only in the area other than both ends of the pin body 12, or on the entire pin body 12. The thickness of the plating layer 13 is not particularly limited. The thickness of the plating layer 13 is preferably in the range of, for example, 0.5 to 5.0 μm.

[0019] The insulating coating 14 covers the pin body 12 or a portion of the surface of the pin body 12 having the plating layer 13. The insulating coating 14 does not need to cover both ends of the pin body 12 or the plating layer 13. The insulating coating 14 is a resin coating, similar to insulating coatings for general wires. Examples of resins that can be used for the insulating coating 14 are not particularly limited as long as they have insulating properties. Examples of resins include parylene resin, acrylic resin, polyurethane resin, nylon resin, polyester resin, epoxy resin, polyesterimide resin, polyamide resin, polyamideimide resin, and paraxylene resin. The thickness of the insulating coating 14 is appropriately selected depending on the application. The thickness of the insulating coating 14 is preferably in the range of 0.5 to 10.0 μm, for example.

[0020] The planar shape of the tip of the electrical characteristics test probe pin 10 is not particularly limited. The tip shape of the electrical characteristics test probe pin 10 may be hemispherical, pointed, or angular. The tip shape of the electrical characteristics test probe pin 10 is set appropriately according to the intended use.

[0021] (Probe card configuration) Figure 2 shows a partial configuration of a probe card 50 used to test the electrical characteristics of an object 70 to be tested.

[0022] As shown in Figure 2, the probe card 50 has a probe card body 52 and lead wires 54. Figure 2 shows how the electrical characteristics of the object to be tested 70 (for example, an integrated circuit) are being tested by bringing one end of the probe pins 10 for electrical characteristic testing of the probe card body 52 into contact with the area 72 to be tested on the object to be tested 70.

[0023] The probe card body 52 includes a first plate 62, a second plate 64, and the aforementioned plurality of electrical characteristic test probe pins 10.

[0024] The first plate 62 positions one end of each of the multiple electrical characteristic test probe pins 10. The first plate 62 has multiple first through holes 63 formed therein. One end of each of the electrical characteristic test probe pins 10 is inserted into each of the multiple first through holes 63. The number of first through holes 63 is not particularly limited. The number of first through holes 63 is appropriately designed according to the number of inspection targets 72. The arrangement of the multiple first through holes 63 is appropriately designed according to the positions of the inspection targets 72. The shape of the opening of the first through hole 63 is not particularly limited. The shape of the opening of the first through hole 63 may be rectangular or circular. The shape of the opening of the first through hole 63 is preferably a rectangle larger than the size of the cross-section of the electrical characteristic test probe pin 10, and particularly preferably a square, because the cross-sectional shape of the electrical characteristic test probe pin 10 is trapezoidal.

[0025] The second plate 64 positions the other ends of the multiple electrical characteristic test probe pins 10. The second plate 64 is arranged parallel to the first plate 62, spaced apart from it, so as to overlap it. Multiple second through holes 65 are formed in the second plate 64. The other ends of the electrical characteristic test probe pins 10 are inserted into each of the multiple second through holes 65. The number of second through holes 65 is the same as the number of first through holes 63. The shape of the openings of the second through holes 65 is not particularly limited. The shape of the openings of the second through holes 65 may be rectangular or circular. The shape of the openings of the second through holes 65 is preferably a rectangle larger than the size of the cross-section of the electrical characteristic test probe pins 10, and a square is particularly preferred, since the cross-sectional shape of the electrical characteristic test probe pins 10 is trapezoidal.

[0026] The first plate 62 and the second plate 64 are preferably made of an insulator having the necessary strength. The first plate 62 and the second plate 64 may be a single integrated component rather than separate parts. As will be described in detail later, the first plate 62 and the second plate 64 are arranged parallel to each other such that the first through-hole 63 and the corresponding second through-hole 65 do not coincide in the planar direction.

[0027] The probe pin 10 for electrical characteristic testing is a rod-shaped member in which one end (the lower end in Figure 2) and the other end (the upper end in Figure 2) are electrically connected. The other end of the probe pin 10 for electrical characteristic testing is connected to an inspection device (not shown) via a lead wire 54. By moving at least one of the probe card body 52 and the object to be inspected 70, one end of the probe pin 10 for electrical characteristic testing is brought into contact with the inspection target location 72 of the object to be inspected 70.

[0028] The structure of the electrical characteristic test probe pin 10 is not particularly limited as long as it has a trapezoidal cross-section with different lengths for the upper base a and lower base b, and can electrically connect the inspection target area 72 and the inspection device. The electrical characteristic test probe pin 10 may consist only of a pin body 12, or it may consist of a combination of a pin body 12 and a plating layer 13, or it may consist of a combination of a pin body 12 and an insulating coating 14. Of the surface of the electrical characteristic test probe pin 10, areas other than the area that contacts the inspection target area 72 and the area that connects to the lead wire 54 may be covered with an insulating coating 14 or the like. Furthermore, since the electrical characteristic test probe pin 10 is pressed against the inspection target area 72, it is preferable that the electrical characteristic test probe pin 10 has elasticity. For example, the electrical characteristic test probe pin 10 may be made of a material with high elasticity.

[0029] In the probe card body 52, the multiple electrical characteristic test probe pins 10 are arranged such that the trapezoidal shapes in their respective cross-sections are oriented in the same direction. Furthermore, as described above, since the first through hole 63 and the corresponding second through hole 65 do not coincide in the planar direction, the multiple electrical characteristic test probe pins 10 are arranged at an inclination with respect to the vertical direction (up and down direction in Figure 2). The inclination angle of the multiple electrical characteristic test probe pins 10 is not particularly limited. Preferably, the inclination angle of the multiple electrical characteristic test probe pins 10 is within the range of 0.5 to 45.0°.

[0030] Multiple lead wires 54 are each connected to one end of multiple electrical characteristic test probe pins 10. Furthermore, multiple lead wires 54 are each connected to a test device (not shown). In other words, multiple lead wires 54 connect the multiple electrical characteristic test probe pins 10 of the probe card body 52 to the test device. In the example shown in Figure 2, the lead wires 54 may or may not be fixed to the electrical characteristic test probe pins 10 by soldering.

[0031] The object to be inspected 70 is not particularly limited. Examples of the object to be inspected 70 include electronic components such as integrated circuits, semiconductor chips, and connectors, and wiring boards such as printed circuit boards, flexible circuit boards, multilayer circuit boards, and semiconductor package circuit boards.

[0032] Here, the positional relationship between the first plate 62, the second plate 64, and the probe pins 10 for electrical characteristic testing will be explained. Figure 3A is a schematic plan view illustrating the positional relationship between the first plate 62, the second plate 64, and the probe pins 10 for electrical characteristic testing, and Figure 3B is a schematic cross-sectional view along line A-A shown in Figure 3A. Figure 4A is a diagram showing the configuration of a probe card of a comparative example, and Figure 4B is a diagram showing the configuration of the probe card 40 of the embodiment. In the probe card of the comparative example, the cross-sectional shape perpendicular to the length direction of the probe pins for electrical characteristic testing is rectangular. Here, we will explain using the example where the probe pins 10 for electrical characteristic testing are trapezoidal, the number of first through holes 63 formed in the first plate 62 is 6, and the number of second through holes 65 formed in the second plate 64 is 6. Also, the shorter side of the base of the trapezoidal shape is the upper base a. In Figures 3A, B, 4A, and B, the inclination angle of the probe pins 10 for electrical characteristic testing is exaggerated.

[0033] As shown in Figures 3A and 3B, the probe pins 10 for electrical characteristic testing are positioned with one end on the first plate 62 and the other end on the second plate 64. In the example shown in Figures 3A and 3B, multiple probe pins 10 for electrical characteristic testing are arranged so that the upper base a of the trapezoid is located on the right side of the paper. The second plate 64 is positioned parallel to the first plate 62 and spaced apart in the height direction. Furthermore, the second plate 64 is positioned such that the second through-hole 65 does not coincide with the corresponding first through-hole 63 in the planar direction (front-back, left-right direction in Figure 3B) relative to the first plate 62. More specifically, the second plate 64 is positioned offset from the first plate 62 toward the upper base a side in the cross-section of the probe pins 10 for electrical characteristic testing. The amount of lateral displacement of the second plate 64 relative to the first plate 62 is not particularly limited. The amount of lateral displacement of the second plate 64 relative to the first plate 62 is preferably in the range of 0.01 to 10 mm, for example.

[0034] As shown in Figure 4A, in the comparative example probe card, the cross-sectional shape of the electrical characteristic test probe pins 10 is rectangular. Therefore, when the tips of the electrical characteristic test probe pins 10 are brought into contact with the inspection target area 72 of the object to be inspected 70 (e.g., integrated circuit), the multiple electrical characteristic test probe pins 10 bend in various directions. As a result, the electrical characteristic test probe pins 10 come into contact with each other, causing inspection abnormalities.

[0035] On the other hand, as shown in Figure 4B, in this embodiment, since the length of the upper base a of the trapezoid is shorter than the length of the lower base b, when the tip of the electrical characteristic test probe pin 10 is brought into contact with the inspection target area 72 of the object to be inspected 70 (for example, an integrated circuit), all of the electrical characteristic test probe pins 10 deform uniformly toward the upper base a side. In the example shown in Figure 4B, the electrical characteristic test probe pin 10 bends in the direction in which the first plate 62 is laterally shifted relative to the second plate 64. Also, as shown in Figure 4B, when the second plate 64 is shifted toward the upper base a side of the trapezoidal shape, the first through hole 63 and the electrical characteristic test probe pin 10 and the second through hole 65 and the electrical characteristic test probe pin 10 come into contact, causing sliding during inspection and resulting in wear between them. In particular, the first through hole 63 is located directly above the object to be inspected 70, and the falling of foreign matter due to wear will adversely affect the characteristics of the object to be inspected 70. When the second plate 64 is shifted relative to the first plate 62 toward the trapezoidal upper base a, the lower opening of the first through hole 63 comes into contact with the lower base b, and the upper opening of the first through hole 63 comes into contact with the upper base a. Since the length of the lower base b is longer than the length of the upper base a, and the pressure in contact with the first through hole 63 is lower on the lower base b side than on the upper base a side, the falling of foreign matter due to wear can be suppressed.

[0036] (Effects) As described above, according to the present invention, since the cross-sectional shape of the probe pin for electrical characteristic testing is a trapezoidal shape with different lengths for the upper and lower bases, the probe pin for electrical characteristic testing can be deformed more appropriately compared to the prior art literature.

[0037] The probe pin for electrical characteristic testing of the present invention can be used in contact probes and electrical characteristic testing devices.

[0038] 10 Probe pin for electrical characteristic testing 12 Pin body 13 Plating layer 14 Insulating coating 50 Probe card 52 Probe card body 54 Lead wire 62 First plate 63 First through hole 64 Second plate 65 Second through hole 70 Object to be inspected 72 Location to be inspected

Claims

1. A probe pin for electrical property testing having a pin body containing a conductive material, characterized in that the cross-sectional shape in a direction perpendicular to the longitudinal direction of the pin body is a trapezoidal shape with different lengths for the upper and lower bases.

2. A probe pin for electrical property testing according to claim 1, wherein the conductive material is a copper alloy containing 6.0 to 30.0% by mass of silver, with the remainder being copper and unavoidable impurities.

3. A probe pin for electrical property testing according to claim 2, characterized in that the silver content in the copper alloy is in the range of 10.0 to 25.0% by mass.

4. A probe pin for electrical characteristic testing according to claim 1, further comprising a plating layer disposed on the surface of the pin body.

5. A probe pin for electrical characteristic testing according to claim 1, further comprising an insulating coating that covers at least a portion of the pin body.

6. A probe card comprising: a first plate having a plurality of first through holes; a second plate spaced apart from the first plate and having a plurality of second through holes; and a plurality of electrical characteristic testing probe pins according to claim 1, one end of which is inserted into the first through hole and the other end of which is inserted into the second through hole corresponding to the first through hole.

7. A probe card according to claim 6, characterized in that, in the cross-section, the length in the height direction of the trapezoidal shape is shorter than the width direction perpendicular to the height direction.

8. A probe card according to claim 6, wherein the cross-sectional shape of each of the plurality of probe pins for electrical characteristic testing is the same, and the plurality of probe pins for electrical characteristic testing are arranged such that the trapezoidal shapes in each of the cross-sections are oriented in the same direction.

9. A probe card according to claim 6, characterized in that the second plate is positioned offset from the first plate toward the upper bottom side of the trapezoidal shape such that the second through hole and the corresponding first through hole do not coincide in the planar direction.

10. A probe card according to claim 6, further comprising a plurality of lead wires connected to one end of each of the plurality of electrical characteristic test probe pins, each inserted into each of the plurality of first through holes of the first plate.

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