probe

Abstract

To provide a probe with which it is possible to prevent reduction of a load due to a current flowing in the probe.SOLUTION: A probe comprises a body part, and a spring part having greater electrical resistivity and elastic modulus than the body part. The body part has a structure in which a tip part, a trunk part that elastically deforms, and a base end part are connected in the order stated. The spring part has a structure in which a first junction part that is joined to the tip part, an elastic deformation part that elastically deforms, and a second junction part that is joined to the base end part are connected in the order stated.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to a probe used for measuring the characteristics of a test object. 【Background Art】 【0002】 Probes are used to measure the characteristics of integrated circuits and the like. In an inspection using a probe, one end of the probe is brought into contact with a test object, and the other end of the probe is brought into contact with a terminal (hereinafter referred to as a "land") arranged on a circuit board or the like. The land is electrically connected to an inspection device such as a tester. 【0003】 In the inspection of a test object, in order to ensure electrical connection between the test object, the land, and the probe, a probe having a spring portion that elastically deformes between one end and the other end is used. By bringing one end of the probe having a spring portion into contact with the test object and the other end into contact with the land, elastic deformation occurs in the spring portion. The force (hereinafter referred to as "load") generated by the elastic deformation of the spring portion can stabilize the contact between the probe, the test object, and the land. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2010-281583 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 When an abnormality occurs in the object under test, such as a short circuit in its internal circuitry, an excessive current (hereinafter also referred to as "overcurrent") flows through the probe during the inspection of the object's electrical characteristics. Due to the Joule heating caused by the overcurrent, the probe overheats, which can lead to plastic deformation or even melting of the probe. When plastic deformation occurs in the probe, the load decreases, making it impossible to stabilize the contact between the probe and the object under test and the land. 【0006】 In view of the above problems, the present invention aims to provide a probe that can prevent a decrease in load caused by the current flowing through the probe. [Means for solving the problem] 【0007】 According to one aspect of the present invention, a probe is provided having a main body and a spring portion having greater electrical resistivity and elastic modulus than the main body, wherein the main body and the spring portion are connected in parallel. The main body has a configuration in which a tip portion, an elastically deformable body portion, and a base portion are connected in this order. The spring portion has a configuration in which a first joint portion joined to the tip portion, an elastically deformable elastic deformation portion, and a second joint portion joined to the base portion are connected in this order. [Effects of the Invention] 【0008】 According to the present invention, it is possible to provide a probe that can prevent a decrease in load caused by the current flowing through the probe. [Brief explanation of the drawing] 【0009】 [Figure 1] Figure 1 is a schematic diagram showing the configuration of a probe according to an embodiment. [Figure 2] Figure 2 is a schematic diagram showing the configuration of the main body of the probe according to the embodiment. [Figure 3] Figure 3 is a schematic diagram showing the configuration of the spring portion of the probe according to the embodiment. [Figure 4] Figure 4 is a schematic diagram showing the connection configuration between the main body and spring portion of the probe according to the embodiment. [Figure 5]Figure 5 is a graph showing the relationship between the current flowing through the probe and the load. [Figure 6] Figure 6 is a schematic diagram showing the configuration of a comparative example probe. [Figure 7] Figure 7 is a schematic diagram showing the configuration of a probe according to the first modified embodiment. [Figure 8] Figure 8 is a schematic diagram showing the connection configuration between the main body and spring portion of the probe according to the first modified embodiment. [Figure 9] Figure 9 is a schematic diagram showing the configuration of a probe according to a second modified example of the embodiment. [Figure 10] Figure 10 is a schematic diagram showing the connection configuration between the main body and spring portion of the probe according to a second modified example of the embodiment. [Modes for carrying out the invention] 【0010】 Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, identical or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the lengths and thickness ratios of each part may differ from those of reality. Furthermore, there are parts in the drawings where the dimensional relationships and ratios differ from those of other parts. 【0011】 The probe 1 according to an embodiment of the present invention shown in Figure 1 is used to inspect the electrical characteristics of an object under test. The probe 1 comprises a main body portion 10 and a spring portion 20. 【0012】 As shown in Figure 2, the main body 10 of the probe 1 has a configuration in which a tip portion 11, a body portion 12, and a base portion 13 are connected in this order. One end of the tip portion 11 is connected to the body portion 12, and the other end of the tip portion 11 is protruding. The tip of the protruding tip portion 11 will also be referred to as the "first end of the probe 1" below. One end of the base portion 13 is connected to the body portion 12, and the other end of the base portion 13 extends in a straight line. The tip of the straight-extended end of the base portion 13 will also be referred to as the "second end of the probe 1" below. The body portion 12 is curved, and when the probe 1 comes into contact with the object to be inspected, the body portion 12 elastically deforms. 【0013】 As shown in Figure 3, the spring portion 20 of the probe 1 has a configuration in which a first joint portion 21, an elastically deformable portion 22, and a second joint portion 23 are connected in this order. The elastically deformable portion 22 elastically deforms when the probe 1 comes into contact with the object to be inspected during inspection. 【0014】 When the main body 10 of the probe 1 comes into contact with the object under inspection, both the body portion 12 and the elastic deformation portion 22 undergo elastic deformation, but the shapes of the body portion 12 and the elastic deformation portion 22 may differ. For example, the shapes and materials of the body portion 12 and the elastic deformation portion 22 may differ. By changing the shape of the body portion 12 and the shape of the elastic deformation portion 22, the elasticity of the body portion 12 and the elastic deformation portion 22 can be made equal even if they are made of different materials. By having equal elasticity in the body portion 12 and the elastic deformation portion 22, the posture of the end of the probe 1 that comes into contact with the object under inspection can be stabilized. The shapes of the body portion 12 and the elastic deformation portion 22 may be set according to the stress generated in the probe 1 when the probe 1 comes into contact with the object under inspection, the displacement of the tip of the probe 1 in a direction parallel to the surface of the object under inspection (scrub amount) at the time of contact, and the materials of the main body portion 10 and the spring portion 20. 【0015】 Note that the body portion 12 does not necessarily have to have elasticity. That is, the elasticity of the probe 1 when the probe 1 contacts the subject may be exhibited only in the elastic deformation portion 22. Even if sagging occurs in the body portion 12 due to, for example, Joule heat caused by the current flowing through the main body portion 10 when the elastic deformation portion 22 alone elastically deforms during inspection, the elasticity of the probe 1 does not decrease. As a result, the probe 1 can be used for inspecting the subject over a long period of time. Also, the elastic modulus of the elastic deformation portion 22 may be larger than the elastic modulus of the body portion 12. Since the elastic modulus of the elastic deformation portion 22 is larger than that of the body portion 12, the load due to the elastic deformation of the probe 1 during inspection mainly occurs in the spring portion 20. Therefore, the influence of the sagging occurring in the body portion 12 on the elasticity of the entire probe 1 is reduced. 【0016】 As shown in FIG. 4, the first joint portion 21 of the spring portion 20 is joined to the tip portion 11 of the main body portion 10. And the second joint portion 23 of the spring portion 20 is joined to the base end portion 13 of the main body portion 10. In FIG. 4, the interval D between the main body portion 10 and the spring portion 20 is explicitly shown in order to make the joining portion between the main body portion 10 and the spring portion 20 easy to understand. For joining the main body portion 10 and the spring portion 20, methods such as diffusion bonding, resistance welding, brazing, etc. may be used. As shown in FIGS. 1 and 4, the main body portion 10 and the spring portion 20 are connected in parallel. 【0017】 In the probe 1, the electrical resistivity and the elastic modulus of the spring portion 20 are larger than those of the main body portion 10. That is, current flows more easily through the main body portion 10 than through the spring portion 20. And the elastic modulus of the elastic deformation portion 22 of the spring portion 20 is larger than that of the body portion 12 of the main body portion 10. 【0018】 In the inspection of a subject, a current flows between the subject and an inspection device such as a tester via probe 1. For example, the first end (the tip of tip portion 11) of probe 1 contacts a land, and the second end (the tip of base end portion 13) of probe 1 contacts an electrode terminal of the subject. As shown in FIGS. 1 and 4, the ends of the tip portion 11 and the base end portion 13 of the main body portion 10 protrude axially more than the ends of the spring portion 20. The "axial direction" is the direction from the tip portion 11 to the base end portion 13 of probe 1. Since the ends of the tip portion 11 and the base end portion 13 protrude more than the ends of the spring portion 20, the spring portion 20 does not contact the electrode terminal and the land of the subject. In the case where the tip of the spring portion 20 is not in contact with the subject and the land, the ends of the tip portion 11 and the base end portion 13 may not protrude axially more than the ends of the spring portion 20. 【0019】 Probe 1, in which the main body portion 10 has a body portion 12 and the spring portion 20 has an elastic deformation portion 22, is extendable and contractible along the axial direction. The extension and contraction directions of the body portion 12 and the elastic deformation portion 22 are the axial direction of probe 1. When measuring the subject, probe 1 extends and contracts along the axial direction. That is, when probe 1 contacts the subject, probe 1 contracts axially, and when probe 1 separates from the subject, probe 1 extends axially. The contact between probe 1 and the subject and the contact between probe 1 and the land can be stabilized by the load generated when probe 1 contracts during the measurement of the subject. 【0020】 For example, with the first end of probe 1 contacting the land, the second end of probe 1 is brought into contact with the subject. At this time, the body portion 12 of the main body portion 10 and the elastic deformation portion 22 of the spring portion 20 contract. When the second end of probe 1 is separated from the subject, the body portion 12 and the elastic deformation portion 22 extend. 【0021】 To extend and retract the probe 1 along the axial direction, the body portion 12 of the main body portion 10 and the elastic deformation portion 22 of the spring portion 20 are configured to be expandable and retractable in the axial direction. In the probe 1 shown in Figure 1, the body portion 12 and the elastic deformation portion 22 are curved in shape. However, the expandable and retractable configuration used for the body portion 12 and the elastic deformation portion 22 is not limited to a curved shape. The body portion 12 and the elastic deformation portion 22 can take various configurations that allow them to be expandable and retractable along the axial direction of the probe 1. 【0022】 The distance between the main body 10 and the spring portion 20, shown as interval D in Figure 4, is preferably set so that the main body 10 and the spring portion 20 do not come into contact when the probe 1 extends or retracts. By setting the interval D so that the main body 10 and the spring portion 20 do not come into contact, damage to the probe 1 caused by contact between the main body 10 and the spring portion 20 when the probe 1 extends or retracts can be reduced. On the other hand, by narrowing the interval D, the probe 1 can be made smaller. In addition, by narrowing the interval D, the distance between adjacent probes 1 can be narrowed, which can accommodate the narrow pitch of the electrode terminals of the object being inspected. 【0023】 In probe 1, by making the electrical resistivity of the main body 10 lower than that of the spring 20, the current flowing through probe 1 during inspection of the object under test mainly flows through the main body 10. Furthermore, in probe 1, by making the elastic modulus of the main body 10 lower than that of the spring 20, the load due to the elastic deformation of probe 1 during inspection of the object under test mainly occurs in the spring 20. 【0024】 By making the main body 10 the primary path for the current flowing through the probe 1, the current flowing through the spring 20 can be reduced. This suppresses the generation of Joule heat in the spring 20 caused by the current flowing through the probe 1 during inspection of the object under test. Alternatively, by having all the current flow through the main body 10 and eliminating the current flowing through the spring 20, the generation of Joule heat in the spring 20 can be eliminated. 【0025】 Since the main path of the current flowing through the probe 1 is the main body 10, the probe 1 can prevent plastic deformation of the spring portion 20 due to the current flowing through the probe 1, even if an overcurrent flows through the probe 1. By preventing plastic deformation of the spring portion 20, the current value at which the probe 1 will no longer be able to obtain the load necessary for measuring the object under inspection (hereinafter also referred to as the "allowable current value") can be improved. Furthermore, the probe 1 can prevent the probe 1 from melting due to an overcurrent flowing through it. 【0026】 The main body 10 may be made of materials such as gold (Au), silver (Ag), copper (Cu), or alloys containing one or more of these metals. The spring 20 may be made of materials such as nickel (Ni) alloy, titanium (Ti) alloy, stainless steel (SUS), or Ni-based heat-resistant alloy. High heat-resistant materials, which were previously unsuitable as probe materials due to their high electrical resistivity, can be used for the spring 20. 【0027】 Figure 5 shows the relationship between the current I flowing through the probe and the load F. The solid line S1 in Figure 5 represents the characteristic relationship between the current I flowing through probe 1 and the load F. The dashed line S2 in Figure 5 represents the characteristic relationship between the current I flowing through comparative probe 1M, which is used in the comparative example shown in Figure 6, and the load F. In comparative probe 1M, the current flows through the curved section, which functions as a spring to generate the load. 【0028】 In Figure 5, the initial load F0 of probe 1 and comparison probe 1M is the load generated in an unused probe with no current flowing through it. The lower limit load F1 is the lower limit of the load required for stable contact between the probe and the object under inspection and the land. In other words, for the dashed line S2, the current I1M at which the load F decays from the initial load F0 to the lower limit load F1 is the allowable current value of comparison probe 1M. On the other hand, for the solid line S1, the current I1 at which the load F decays from the initial load F0 to the lower limit load F1 is the allowable current value of probe 1. The allowable current value is determined by the material, shape, and position and size of the curved part of the probe. The melting current I2 is the current at which the probe melts due to Joule heating caused by the current I. 【0029】 As shown in Figure 5, in the comparison probe 1M, the curved section serves as the path for the current I, making it prone to load reduction due to plastic deformation. Therefore, as shown by the dashed line S2 in Figure 5, the load F falls below the lower limit load F1 at approximately 50% of the melting current I2. For this reason, measures such as lowering the maximum current flowing through the comparison probe 1M are necessary. However, lowering the maximum current flowing through the probe may limit the scope of inspection of the object being inspected. 【0030】 On the other hand, in probe 1, the decrease in load due to plastic deformation of the elastic deformation part 22 can be suppressed by reducing or eliminating the current flowing through the spring part 20. As a result, as shown by the solid line S1 in Figure 5, the allowable current value of probe 1 is improved compared to the comparative probe 1M. 【0031】 As described above, in the probe 1 according to this embodiment, current flows mainly through the main body 10, and the spring portion 20 generates a load due to elastic deformation. Therefore, the decrease in load caused by the current flowing through the probe 1 is suppressed. As a result, the probe 1 can stabilize the contact between the probe 1 and the object to be inspected and the land. 【0032】 <First variation> In probe 1, multiple spring sections 20 may be connected in parallel to the main body section 10. For example, in the probe 1 according to the first modified example shown in Figures 7 and 8, the first spring section 20A and the second spring section 20B are connected in parallel to the main body section 10. As shown in Figure 8, the first spring section 20A and the second spring section 20B are joined to the main body section 10, with the main body section 10 in between. 【0033】 A probe 1 having multiple spring sections 20 can further suppress the decrease in load caused by the current flowing through the probe 1. By suppressing the decrease in load, the allowable current value of the probe 1 can be increased. Also, by suppressing the decrease in load, the operating temperature of the probe 1 can be increased. Furthermore, because the design freedom of the load is increased, the probe 1 can be used for inspections that require a large load. For example, a large load is required for inspecting an object whose electrode material is a solder bump. A probe 1 having multiple spring sections 20 can be used for inspections that require a large load. 【0034】 <Second variation> In probe 1, multiple main body parts 10 may be connected in parallel to the spring part 20. For example, in the probe 1 according to the second modified example shown in Figures 9 to 10, the first main body part 10A and the second main body part 10B are connected in parallel to the spring part 20. As shown in Figure 10, the first main body part 10A and the second main body part 10B are joined to the spring part 20 with the spring part 20 in between. 【0035】 The multiple main body parts 10, each connected in parallel to the spring part 20, may be electrically insulated from one another. The probe 1 shown in Figure 9 can be used, for example, as a Kelvin probe. Alternatively, the allowable current value of the probe 1 can be increased by bringing multiple main body parts 10 into contact with the same electrode terminal. When bringing them into contact with the same electrode terminal, the multiple main body parts 10 do not need to be insulated from one another. 【0036】 (Other embodiments) Although the present invention has been described above by embodiments, the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure. 【0037】 For example, although the above description of probe 1 has only one main body 10 and one spring 20, probe 1 may have multiple main body 10s and multiple spring 20s. 【0038】 Thus, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined solely by the inventive features relating to the claims that are reasonable based on the above description. [Explanation of Symbols] 【0039】 1…Probe 10...Main body 11...Tip 12... Torso 13...Proximal end 20... Spring part 21…First joint part 22...Elastic deformation part 23…Second joint part

Claims

[Claim 1] The main body has a configuration in which the tip, body, and base are connected in this order, The spring portion has a configuration in which a first joint portion that connects to the tip, an elastically deformable elastic deformation portion, and a second joint portion that connects to the base end are connected in this order, and the spring portion has a greater electrical resistivity and elastic modulus than the main body portion. Equipped with, The torso portion of the main body and the elastically deformable portion of the spring both have a curved shape that can expand and contract in the axial direction, and are formed of different shapes and materials from each other. The main body portion has ends, the tip portion and the base portion, that protrude axially from the ends of the spring portion. The main body and the spring are connected in parallel with a gap between them. probe. [Claim 2] The probe according to claim 1, wherein the ends of the tip portion and the base portion each protrude in the axial direction more than the ends of the spring portion. [Claim 3] The probe according to claim 1 or 2, comprising a plurality of spring portions, each connected in parallel to the main body portion. [Claim 4] The probe according to claim 1 or 2, comprising a plurality of main body portions, each connected in parallel to the spring portion. [Claim 5] The probe according to claim 4, wherein a plurality of main body portions, each connected in parallel to the spring portion, are electrically insulated from one another.

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