Probe

Abstract

To provide a probe capable of suppressing warpage caused by a protective material arranged on a side surface.SOLUTION: The probe 10 includes: a conductive columnar base material 11 having a first surface S1 and a second surface S2 facing a direction opposite to the first surface S1; a first protective material 121 arranged on the first surface S1 and made of a material having higher hardness than the base material 11; and a second protective material 122 arranged on the second surface S2, made of a material having higher hardness than the base material 11, and having a film thickness different from that of the first protective material 121.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a probe used for inspecting electrical characteristics of an object under test. [Background technology]

[0002] An electrical connection device including a probe is used to test the electrical characteristics of a test object such as a semiconductor integrated circuit in a wafer state. In a test using a probe, one end of the probe held by a probe head is brought into contact with an electrode pad of the 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 printed circuit board or the like. The land is electrically connected to a tester or other test device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-91870 Summary of the Invention [Problem to be solved by the invention]

[0004] The probe is supported by a probe head having a guide plate, with the probe penetrating a guide hole formed in the guide plate. To prevent damage to the probe due to contact between the inner wall surface or opening of the guide hole and the side surface of the probe, the side surface of the probe is covered with a protective material made of a material harder than the base material of the probe. However, the present inventors have found that the formation of the protective material causes stress to be applied to the probe during the manufacturing process, resulting in warping of the probe.

[0005] An object of the present invention is to provide a probe that can suppress warping caused by a protective material placed on the side surface. [Means for solving the problem]

[0006] A probe according to one embodiment of the present invention comprises a conductive, columnar base material having a first surface and a second surface facing in the opposite direction to the first surface, a first protective material arranged on the first surface and made of a material harder than the base material, and a second protective material arranged on the second surface and made of a material harder than the base material and having a film thickness different from that of the first protective material. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a probe that can suppress warping caused by a protective material disposed on the side surface. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a probe according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic process diagram (part 1) for explaining the method for manufacturing a probe according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic process diagram for explaining the method for manufacturing a probe according to an embodiment of the present invention (part 2). [Figure 4] FIG. 4 is a schematic process diagram for explaining the method for manufacturing a probe according to an embodiment of the present invention (part 3). [Figure 5] FIG. 5 is a schematic process diagram for explaining the method for manufacturing a probe according to an embodiment of the present invention (part 4). [Figure 6] FIG. 6 is a schematic process diagram for explaining the method for manufacturing a probe according to an embodiment of the present invention (part 5). [Figure 7] FIG. 7 is a graph showing the amount of warping of probes in which the first protective material and the second protective material have the same film thickness. [Figure 8] FIG. 8 is a graph showing the amount of warping of a probe in which the ratio of the thickness of the first protective material to the thickness of the second protective material is 2:1. [Figure 9] FIG. 9 is a table showing the results of measuring the amount of warpage of the probe when the film thickness of the first protective material and the second protective material is changed. [Figure 10]FIG. 10 is a schematic diagram showing the configuration of a probe according to a modified embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, identical or similar parts are designated by identical or similar reference numerals. However, it should be noted that the drawings are schematic, and the thickness ratios of the various parts may differ from those in reality. It goes without saying that the dimensional relationships and ratios of parts included in the drawings may differ from each other. The embodiments shown below exemplify devices and methods for embodying the technical ideas of the present invention, and the embodiments of the present invention are not limited to the following in terms of the materials, shapes, structures, arrangements, and manufacturing methods of the components.

[0010] A probe 10 according to an embodiment of the present invention shown in FIG. 1 is used to inspect the electrical characteristics of an object under inspection. The probe 10 includes a columnar base material 11 having a first surface S1 and a second surface S2 facing in the opposite direction from the first surface S1, a first protective material 121 disposed on the first surface S1, and a second protective material 122 disposed on the second surface S2. In the probe 10 shown in FIG. 1, the first protective material 121 is embedded in the first surface S1 of the base material 11 with its surface exposed. The second protective material 122 is laminated on the surface of the second surface S2 of the base material 11. The base material 11 is made of a conductive material. The first protective material 121 is made of a material harder than the base material 11. The second protective material 122 is made of a material harder than the base material 11 and has a different film thickness from the first protective material 121. Hereinafter, unless otherwise specified, the first protective material 121 and the second protective material 122 will be referred to as protective material 12.

[0011] As shown in Fig. 1, the direction in which the columnar probe 10 extends is the Z direction. Furthermore, a plane perpendicular to the Z direction is the XY plane, with the X direction being the vertical direction in Fig. 1 and the Y direction being the depth direction in Fig. 1. The normal directions of the first surface S1 and the second surface S2 are parallel to the X direction. The cross section of the base material 11 perpendicular to the Z direction may be, for example, rectangular.

[0012] The probe 10 has a distal end surface 101, which is one end surface, and a proximal end surface 102, which is the other end surface. When testing an object under test, the distal end surface 101 of the probe 10 comes into contact with an electrode pad of the object under test. The proximal end surface 102 of the probe 10 comes into contact with a land on a substrate included in an electrical connection device that includes the probe 10. For example, the land is electrically connected to a testing device such as an IC tester via wiring inside the substrate.

[0013] 1 includes a tip portion 13, one end of which is connected to a first end portion 111 of a base material 11. The end face of the other end of the tip portion 13 is a tip surface 101. The end face of a second end portion 112 of the base material 11 is a base surface 102.

[0014] The tip portion 13 comes into contact with a pad of the test object when testing the electrical characteristics of the test object. For this reason, the tip portion 13 is preferably made of a material that is harder and more conductive than the base material 11. The materials of the tip portion 13 and the base material 11 may be selected so that the conductivity of the tip portion 13 and the base material 11 is equal or higher than that of the base material 11.

[0015] For example, the material of the tip portion 13 may be rhodium (Rh), platinum (Pt), or other precious metals. The material of the base material 11 may be nickel (Ni), nickel alloy, gold (Au), silver (Ag), copper (Cu), palladium (Pd), palladium alloy, rhodium (Rh), rhodium alloy, or other precious metals. The base material 11 may be a single material or a laminate structure of different materials. The material of the protective material 12 may be, for example, rhodium, rhodium alloy, palladium, palladium alloy, or other precious metals. The first protective material 121 and the second protective material 122 may be the same material or different materials.

[0016] A method for manufacturing the probe 10 shown in FIG. 1 will be described below with reference to the drawings.

[0017] First, as shown in Fig. 2, a sacrificial layer 110 is formed on the upper surface of the substrate 100, and a first protective material 121 is selectively formed on the upper surface of the sacrificial layer 110. For example, photolithography may be used to form the first protective material 121 into a predetermined shape when viewed from the X direction (hereinafter also referred to as "planar view"). Next, as shown in Fig. 3, a base material 11 is formed on the upper surface of the sacrificial layer 110 to cover the first protective material 121. As a result, the first protective material 121 is disposed on a first surface S1 of the base material 11.

[0018] 4, a second protective material 122 is formed in a predetermined shape on the first surface S1 of the base material 11 using a photolithography technique or the like. Then, as shown in FIG. 5, a tip portion 13 connected to the first end portion 111 of the base material 11 is formed in a predetermined shape.

[0019] After forming the tip portion 13, as shown in FIG. 6, the sacrificial layer 110 is etched away so that the undersides of the first protective material 121, the base material 11, and the tip portion 13 are exposed. The process of etching away the sacrificial layer 110 forms a space between the probe 10 and the substrate 100. At this time, the probe 10 and the substrate 100 are bonded together by the sacrificial layer 110 that remains unremoved. As a result, the second end 112 of the base material 11 is bonded to the substrate 100 and floats above the substrate 100. In other words, the probe 10 is supported by the substrate 100 in a cantilever structure with the second end 112 as a fixed end and the first end 111 as a free end. At this time, the base material 11 may be formed into a predetermined shape in plan view by, for example, an etching process using photolithography technology.

[0020] The probe 10 in the cantilever structure described above is subjected to an annealing process in which it is heated at a predetermined temperature for a predetermined time, after which the probe 10 is separated from the substrate 100, and the probe 10 is completed.

[0021] The position of the base material 11 where the protective material 12 is formed can be set arbitrarily. For example, the protective material 12 may be formed over the entire axial length of the base material 11. Alternatively, the first protective material 121 may be arranged in a region of the first surface S1 that faces the second surface S2 on which the second protective material 122 is arranged, in a portion of the axial direction of the base material 11. In other words, the first protective material 121 and the second protective material 122 may be selectively arranged in regions that face each other. Furthermore, the thickness of the protective material 12 is formed to be thinner than the thickness of the base material 11. For example, the thicknesses of the first protective material 121 and the second protective material 122 may each be 10% or less of the thickness of the base material 11.

[0022] The present inventors have found that warping of the probe 10 occurs during the annealing step in the above-described manufacturing process, depending on the film thickness of the protective material 12. This warping of the probe 10 is caused by manufacturing variations in the film thickness of the protective material 12. For example, when the probe 10 is manufactured by setting the first protective material 121 and the second protective material 122 to the same film thickness, the first protective material 121 may become thicker or the second protective material 122 may become thicker. For this reason, warping of the probe 10 occurs due to an imbalance in the stresses of the base material 11 and the protective material 12 during the annealing step.

[0023] 7 shows the variation in the amount of warping of the probes 10 when a plurality of probes 10 are manufactured so that the first protective material 121 and the second protective material 122 have the same film thickness. In FIG. 7, the vertical axis represents the amount of warping, and the horizontal axis represents the distance from the base end surface 102 in the direction toward the tip end surface 101.

[0024] 7, when the probe 10 is manufactured with the first protective material 121 and the second protective material 122 having the same film thickness, the amount of warping is large and there is a large variation in the position of the tip end surface 101. Furthermore, as circled, there is a mixture of probes 10 in which the tip end surface 101 is lower than the base end surface 102 and probes 10 in which the tip end surface 101 is higher than the base end surface 102.

[0025] As described above, when probes 10 are manufactured by setting the film thickness of the first protective material 121 and the second protective material 122 to the same value, the amount of warping of the probes 10 varies greatly. Therefore, in an electrical connection device including a plurality of probes 10, there is a risk of variation in the behavior of the probes 10 when they come into contact with the electrode pads of the test object. For example, variation in the strength of contact between the tip surface 101 of the probe 10 and the electrode pad may result in the probes 10 being significantly scraped off from the tip surface 101 when sliding on the electrode pad. Furthermore, there is a risk of the probes 10 arranged in the electrical connection device coming into contact with each other.

[0026] Fig. 8 shows the variation in the amount of warping of the probes 10 when a plurality of probes 10 are manufactured so that the ratio of the thickness of the first protective material 121 to the second protective material 122 is 2 to 1. In Fig. 8, the vertical axis represents the amount of warping, and the horizontal axis represents the distance from the base end surface 102 in the direction toward the tip end surface 101.

[0027] 8, when the ratio of the thickness of the first protective material 121 to the thickness of the second protective material 122 is 2 to 1, there is little variation in both the amount and direction of warping. In other words, variation in the warping of the probe 10 is suppressed.

[0028] As described above, by setting different film thicknesses for the first protective material 121 and the second protective material 122, it is possible to suppress variations in warpage of the probe 10. Fig. 9 shows the results of measuring the amount of warpage of the probe 10 when the ratio (referred to as "HM ratio") between the film thickness D1 of the first protective material 121 and the film thickness D2 of the second protective material 122 is changed.

[0029] 9, when the thickness D1 of the first protective material 121 is thicker than the thickness D2 of the second protective material 122, the amount of warping and the variation in the warping of the probe 10 are small. In addition, the direction of warping can be controlled by switching the magnitude relationship between the thickness D1 of the first protective material 121 and the thickness D2 of the second protective material 122. Furthermore, the variation in the amount of warping can be suppressed by changing the HM ratio.

[0030] As described above, in the probe 10 according to the embodiment, warpage due to the formation of the protective material 12 disposed on the side surface can be suppressed by making the thickness of the first protective material 121 thicker than the thickness of the second protective material 122. However, if the HM ratio is 4 times or more, particularly if the thickness D1 of the first protective material 121 is thicker than the thickness D2 of the second protective material 122, the amount of warpage becomes significantly large. For this reason, the HM ratio is preferably 4 times or less. Furthermore, if the HM ratio is 2 times or less, the amount of warpage and variation can be kept within an acceptable range, so the HM ratio is more preferably 2 times or less. More preferably, if the HM ratio is 1.1 times or more, the warpage suppression effect becomes significant, so it is preferable to set the HM ratio to 1.1 times or more and 2 times or less.

[0031] The probe 10 with reduced warpage reduces variation in the behavior of the probes 10 when they come into contact with electrode pads of an object under test in an electrical connection device including multiple probes 10. This prevents variation in the strength of contact between the tip surface 101 of the probe 10 and the electrode pad, for example. This reduces the amount of wear on the tip surface 101 when the probe 10 slides over the electrode pad. Furthermore, contact between the probes 10 arranged in the electrical connection device is reduced. Furthermore, by reducing variation in the amount and direction of warpage of the probe 10, variation in the position of the tip surface 101 of the probe 10 is reduced, allowing the arrangement pitch of the probes 10 to be narrowed.

[0032] Furthermore, by suppressing variations in the amount and direction of warping, it is easy to mount multiple probes 10 on the electrical connection device. For example, an electrical connection device is used in which a probe head has a guide plate with guide holes formed therein, and the probes 10 are held in a state where they penetrate the guide holes. In this electrical connection device, by suppressing variations in the amount and direction of warping of the probes 10, the probes 10 can be easily inserted into the guide holes.

[0033] (Other embodiments) Although the present invention has been described above by way of the preferred embodiment, the descriptions and drawings that form part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art.

[0034] For example, in the above example, the first protective material 121 is embedded in the base material 11 with its surface exposed on the first surface S1, and the second protective material 122 is disposed by being layered on the second surface S2, but the arrangement of the first protective material 121 and the second protective material 122 is not limited to the above. For example, as shown in Fig. 10, the first protective material 121 may be disposed by being layered on the surface of the first surface S1.

[0035] Thus, it goes without saying that the present invention includes various embodiments not described above. [Explanation of symbols]

[0036] 10 probes 11 Base material 13 Tip 100 boards 101 Tip surface 102 Proximal surface 111 First end 112 Second end 121 1st protective material 122 2nd protective material S1 1st page S2 side 2

Claims

1. A probe used for inspecting electrical characteristics of an object to be inspected, a conductive pillar-shaped base material having a first surface and a second surface facing in an opposite direction to the first surface; a first protective material disposed on the first surface and made of a material having a higher hardness than the base material; a second protective material disposed on the second surface and made of a material having a higher hardness than the base material; Equipped with The first protective material has a thickness greater than that of the second protective material. probe.

2. The probe according to claim 1 , wherein the thickness of the first protective material is equal to or less than twice the thickness of the second protective material.

3. The probe according to claim 1 , wherein the thickness of the first protective material is four times or less the thickness of the second protective material.

4. The probe according to claim 1 , wherein the film thickness of the first protective material is 1.1 times or more and 2 times or less than the film thickness of the second protective material.

5. The probe according to claim 1 , wherein the first protective material is embedded in the first surface of the base material with the surface exposed.

6. The probe according to claim 1 , wherein the second protective material is disposed by lamination on a surface of the second surface.

7. The probe according to claim 1 , wherein the first protective material is arranged in a region of the first surface that faces the second surface on which the second protective material is arranged, in a portion of the axial direction of the base material.

8. The probe according to claim 1 , wherein the first protective material and the second protective material each have a thickness equal to or less than 10% of the thickness of the base material.

9. The probe according to claim 1 , wherein the first protective material and the second protective material are made of the same material.

10. 5. The probe according to claim 1, wherein the first protective material and the second protective material are made of any one of rhodium, a rhodium alloy, palladium, a palladium alloy, and other noble metals.

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