probe
The probe design with a continuous internal wire and strategic material selection reduces electrical resistance and enhances mechanical strength, enabling accurate and durable electrical inspections.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- NIHON MICRONICS KK
- Filing Date
- 2025-01-16
- Publication Date
- 2026-07-29
AI Technical Summary
Existing probes used for inspecting electrical characteristics have high electrical resistance, which hinders accurate measurement and increases the risk of plastic deformation during inspection.
A probe design with a cantilever structure incorporating a projection, base material, and internal wire, where the internal wire is continuous from the tip to the base end, reducing electrical resistance by minimizing interfacial contacts and positioning the wire away from stress-prone areas, and using materials with lower electrical resistance for the wire layers.
The probe achieves lower electrical resistance and improved mechanical strength, allowing for increased current flow and reduced plastic deformation during inspection.
Smart Images
Figure 2026122745000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a probe used for inspecting the electrical characteristics of an inspection object.
Background Art
[0002] In the inspection of an inspection object using a probe, one end (hereinafter referred to as the "tip") of the probe is electrically connected to an inspection pad disposed on the surface of the inspection object, and the other end (hereinafter referred to as the "base end") of the probe is electrically connected to an inspection device such as a tester. A probe having a cantilever structure includes a tip that is a free end, a base end that is a fixed end, and an arm that connects the tip and the base end.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In order to accurately measure the electrical characteristics of an inspection object, it is required that the electrical resistance of the probe be low. An object of the present invention is to provide a probe having a low electrical resistance.
Means for Solving the Problems
[0005] According to one aspect of the present invention, a probe is provided comprising a projection, a base material connected to the projection, and an internal wire enclosed within the base material. The base material includes a tip portion into which the projection is embedded such that the tip of the projection protrudes toward an object to be inspected, a plurality of arms whose one ends are spaced apart from each other and connected to the tip portion, and a base portion into which the other ends of the plurality of arms are spaced apart from each other and connected. The internal wire includes a tip region enclosed within the tip portion, a plurality of arm regions enclosed within the plurality of arms, with one end of each connected to the tip region, and a base region enclosed within the base portion into which the other ends of the plurality of arm regions are connected. [Effects of the Invention]
[0006] According to the present invention, a probe with low electrical resistance can be provided. [Brief explanation of the drawing]
[0007] [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 an enlarged view of the arm surrounding area A in Figure 1. [Figure 3] Figure 3 is a cross-sectional view along the III-III direction in Figure 2. [Figure 4] Figure 4 is a schematic diagram showing an enlarged view of the tip area B in Figure 1. [Figure 5] Figure 5 is a cross-sectional view along the VV direction in Figure 4. [Figure 6] Figure 6 is a schematic diagram showing the state of inspection using the probe according to the embodiment. [Figure 7] Figure 7 is a schematic diagram showing the configuration of the probe in the comparative example. [Figure 8] Figure 8 is a cross-sectional view along the VIII-VIII direction in Figure 7. [Figure 9] Figure 9 is a schematic cross-sectional view illustrating the method for manufacturing a probe according to an embodiment (part 1). [Figure 10] Figure 10 is a schematic cross-sectional view illustrating the method for manufacturing a probe according to the embodiment (part 2). [Figure 11] Figure 11 is a schematic cross-sectional view illustrating the method for manufacturing a probe according to the embodiment (part 3). [Figure 12] Figure 12 is a schematic cross-sectional view illustrating the method for manufacturing a probe according to the embodiment (part 4). [Figure 13] Figure 13 is a schematic cross-sectional view illustrating the method for manufacturing a probe according to the embodiment (part 5). [Figure 14] Figure 14 is a schematic cross-sectional view illustrating the method for manufacturing a probe according to the embodiment (part 6). [Figure 15] Figure 15 is a schematic cross-sectional view illustrating the method for manufacturing a probe according to the embodiment (part 7). [Figure 16] Figure 16 is a schematic cross-sectional view illustrating the problems that arise in the method of manufacturing the probe in the comparative example. [Modes for carrying out the invention]
[0008] 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, it should be noted that the drawings are schematic, and the ratios of the thicknesses of each part may differ from those of reality. Furthermore, it goes without saying that there are parts in the drawings where the dimensional relationships or ratios differ from those of other parts. The embodiments shown below are illustrative examples of devices and methods for realizing the technical idea of this invention, and the embodiments of this invention do not limit the materials, shapes, structures, arrangements, etc. of the components to those described below.
[0009] The probe 1 according to the embodiment shown in FIG. 1 is used for inspecting an inspection object. The probe 1 includes a protrusion 11, a base material 110 connected to the protrusion 11, and an encapsulated wire 120 encapsulated in the base material 110. The base material 110 includes a tip portion 10, a plurality of arms 20, and a base end portion 30. A part of the protrusion 11 is embedded in the tip portion 10 so that the tip of the protrusion 11 protrudes toward the inspection object. One end of each of the plurality of arms 20 is connected to the tip portion 10 while being spaced apart from each other. The other end of each of the plurality of arms 20 is connected to the base end portion 30 while being spaced apart from each other. The probe 1 has a cantilever structure in which a plurality of arms 20 are arranged in parallel with each other and spaced apart between the tip portion 10 which is a free end and the base end portion 30 which is a fixed end.
[0010] In the description of the embodiment, the vertical direction in FIG. 1 is the X direction, the horizontal direction is the Z direction, and the depth direction is the Y direction. For example, the direction in which the tip of the protrusion 11 protrudes is the Z direction, and the plurality of arms 20 extending in the X direction are arranged along the Z direction.
[0011] The base material 110 further includes a fixing portion 40 connected to the base end portion 30. The fixing portion 40 is fixed to a probe head (not shown), and the probe 1 is held by the probe head. An electrical signal propagates between the inspection device and the inspection object via the probe 1 when the fixing portion 40 fixed to the probe head is electrically connected to an inspection device such as a tester. Therefore, a material with high conductivity such as metal may be used for the probe 1 through which the electrical signal propagates.
[0012] The encapsulated wire 120 includes a tip region encapsulated in the tip portion 10, a plurality of arm regions respectively encapsulated in the plurality of arms 20, and a base end region encapsulated in the base end portion 30. The tip region of the encapsulated wire 120 is connected to the protrusion 11. One end of each of the plurality of arm regions is connected to the tip region. The other end of each of the plurality of arm regions is connected to the base end region. In other words, the encapsulated wire 120 is continuous from the tip region connected to the protrusion 11 to the base end region encapsulated in the base end portion 30.
[0013] Over all regions including the tip region, the arm region, and the base end region, the inclusion line 120 is covered by the base material 110. In other words, when viewed from the normal direction (Y direction) of the XZ plane defined by the protruding direction (Z direction) of the protrusion 11 and the extending direction (X direction) of the arm 20, over the entire area of the inclusion line 120, the outer edge of the inclusion line 120 is located inside the outer edge of the base material 110.
[0014] The inclusion line 120 includes a first inclusion line 121 and a second inclusion line 122 laminated in the Y direction. Each of the first inclusion line 121 and the second inclusion line 122 is continuous from the tip region connected to the protrusion 11 to the base end region included in the base end portion 30. The direction in which the first inclusion line 121 and the second inclusion line 122 are laminated is also referred to as the "lamination direction". In the following, the direction in which the second inclusion line 122 is located when viewed from the first inclusion line 121 is upward, and the direction in which the first inclusion line 121 is located when viewed from the second inclusion line 122 is downward. Also, the surface facing upward is the upper surface, and the surface facing downward is the lower surface.
[0015] As shown in FIG. 2 which is an enlarged view of the arm peripheral region A in FIG. 1, when viewed from the lamination direction, the second inclusion line 122 is disposed inside the outer edge of the first inclusion line 121. That is, the width in the Z direction perpendicular to the lamination direction is wider for the first inclusion line 121 than for the second inclusion line 122. Not limited to the arm region shown in FIG. 2, when viewed from the lamination direction, the outer edge of the second inclusion line 122 may be located inside the outer edge of the first inclusion line 121 over the entire area of the inclusion line 120.
[0016] The cross-sectional structure of FIG. 2 is shown in FIG. 3. As shown in FIG. 3, the thickness in the lamination direction (hereinafter also referred to as the "film thickness") is thicker for the second inclusion line 122 than for the first inclusion line 121. Due to the width of the first inclusion line 121 being wider than the width of the second inclusion line 122, the cross-section of the inclusion line 120 has a convex shape with the center of the upper surface bulging.
[0017] The first inner wire 121 may have a structure in which a first upper metal layer 1212 having lower electrical resistance than the first lower metal layer 1211 is laminated on the upper surface of the first lower metal layer 1211. Alternatively, the second inner wire 122 may have a structure in which a second upper metal layer 1222 having lower electrical resistance than the second lower metal layer 1221 is laminated on the upper surface of the second lower metal layer 1221. That is, the second lower metal layer 1221 may be laminated on the first upper metal layer 1212. The thickness of the second upper metal layer 1222 may be greater than the thickness of the first upper metal layer 1212.
[0018] The inner wire 120 is made of a material with lower electrical resistance than the base material 110. As a result, the inner wire 120 is the main current path for the probe 1. The end of the base end 30, which includes the base end region where the arm regions of the inner wire 120 converge, is connected to the fixed part 40. Therefore, the electrical resistance of the probe 1 from the protruding part 11 to the fixed part 40 is reduced, and the allowable current value that flows through the object being inspected can be increased.
[0019] For example, the base material 110 may be a nickel alloy. The first lower metal layer 1211 and the second lower metal layer 1221 may be nickel (Ni), and the first upper metal layer 1212 and the second upper metal layer 1222 may be selected from the group consisting of gold (Au), silver (Ag), and copper (Cu). For example, when Au layers formed by a plating method are used as the first upper metal layer 1212 and the second upper metal layer 1222, the Ni layer becomes a barrier layer between the seed layer and the plating layer.
[0020] As described above, the second inner layer 122 is narrower than the first inner layer 121, while the film thickness of the second inner layer 122 is thicker than that of the first inner layer 121. In particular, as shown in Figure 3, increasing the film thickness of the second upper metal layer 1222 can reduce the electrical resistance of the probe 1.
[0021] As shown in Figure 4, which is an enlarged view of the area B around the tip of Figure 1, the end of the protruding portion 11 protrudes from the tip 10 in the Z direction. As shown in Figure 5, which shows the cross-sectional structure of Figure 4, the portion of the protruding portion 11 embedded in the base material 110 is connected to the first internal encapsulation wire 121 and the second internal encapsulation wire 122. In this way, the internal encapsulation wire 120 is connected to the protruding portion 11 at the tip 10.
[0022] As shown in Figure 6, the inspection of the object to be inspected 2 using the probe 1 is performed with the protrusion 11 in contact with the object to be inspected 2. In the inspection of the object to be inspected 2, in order to ensure electrical connection between the probe 1 and the object to be inspected 2, an overdrive is performed in which the protrusion 11 is further pressed against the object to be inspected 2 while it is in contact with the object to be inspected 2. In the overdrive state, a stress in the Z direction is applied to the arm 20 of the probe 1. As shown in Figure 3, the second internal encapsulation wire 122 is positioned in the center of the base material 110 in the Z direction when viewed from the stacking direction. Then, by connecting one end of the arm region of the internal encapsulation wire 120 contained in the arm 20 to the tip region and merging them, and connecting the other end to the base region and merging them, the internal encapsulation wire 120 can be positioned at a location separated from the outer edge of the probe 1 in the Z direction.
[0023] As described above, in probe 1, by narrowing the width of the second inner casing 122 and connecting both ends of the arm region to the tip region and the base region, the distance from each outer edge of the arm 20, where strong stress is applied, to the second inner casing 122 becomes longer. For this reason, even when a material with lower electrical resistance but lower yield stress (e.g., Au) is used for the second inner casing 122, which has a relatively thick film thickness, compared to the base material 110, plastic deformation of probe 1 due to the stress applied during inspection of the object to be inspected 2 can be suppressed.
[0024] Furthermore, the hardness of the protrusion 11 that contacts the object to be inspected 2 may be higher than the hardness of the base material 110 and the inner wire 120. For example, the material of the protrusion 11 may be rhodium (Rh). This reduces wear of the protrusion 11 caused by the probe 1 contacting the object to be inspected 2.
[0025] Figure 7 shows a comparative probe (hereinafter referred to as "comparative probe 1M"). As shown in Figure 8, comparative probe 1M has a structure in which an inner wire 120, which consists of a lower metal layer 1231 and an upper metal layer 1232, is covered with a base material 110. For example, the base material 110 of comparative probe 1M may be a nickel alloy, the lower metal layer 1231 may be Ni, and the upper metal layer 1232 may be Au. In comparative probe 1M as well, the main current path is the inner wire 120.
[0026] The comparison probe 1M includes an internal wire 120, but the internal wire 120 is not connected to the protruding portion 11. That is, the base material 110 is interposed between the protruding portion 11 and the internal wire 120 at the tip portion 10. As a result, interfaces exist between the protruding portion 11 and the base material 110, and between the base material 110 and the internal wire 120, increasing the electrical resistance of the current path. Furthermore, the internal wires 120 included in each of the multiple arms 20 are not interconnected at the base end portion 30. That is, the base material 110 is interposed between the internal wires 120 of the arms 20 and the base end portion 30. As a result, interfaces exist between the base material 110 and the internal wire 120 at the base end portion 30, increasing the electrical resistance of the current path. Therefore, the electrical resistance of the comparison probe 1M, in which the internal wire 120 is not continuous in the current path from the protruding portion 11 to the base end portion 30, is higher than that of probe 1.
[0027] In contrast, in probe 1 shown in Figure 1, the internal wire 120 is continuous from the protruding portion 11 to the base portion 30. That is, the base material 110 is not interposed in the current path from the protruding portion 11 to the base portion 30. Therefore, the only interface in the current path of probe 1 is the interface between the protruding portion 11 and the internal wire 120 at the tip portion 10. Furthermore, at the base portion 30, each arm region of the internal wire 120 connects to the base portion region. Thus, with probe 1, by making the internal wire 120 continuous and reducing the dissimilar metal interface, the electrical resistance of the current path can be reduced compared to comparative probe 1M. Moreover, with probe 1, by merging the multiple arm regions of the internal wire 120 at the tip region and the base portion, the internal wire 120 of a material with a low yield strength can be positioned away from the outer edge where strong stress is applied. Thus, with probe 1, plastic deformation due to applied stress can be suppressed.
[0028] The manufacturing method of the probe 1 shown in Figure 1 will be described below with reference to the drawing.
[0029] First, a first photoresist film 201 is formed on the upper surface of the substrate 100. Then, as shown in Figure 9, the first photoresist film 201 is patterned so that the upper surface of the substrate 100 in the region where the first encapsulation line 121 is to be formed is exposed. Next, as shown in Figure 10, the first encapsulation line 121 is formed on the upper surface of the substrate 100 that is exposed in the remaining region where the first photoresist film 201 has been formed. Specifically, a first lower metal layer 1211 is formed on the upper surface of the substrate 100, and a first upper metal layer 1212 is formed on the upper surface of the first lower metal layer 1211. For example, the first lower metal layer 1211 may be a Ni layer, and the first upper metal layer 1212 may be an Au layer. In other words, a conductive seed layer may be formed on the upper surface of the substrate 100, and then a Ni layer may be formed as a barrier layer. The width of the first encapsulating wire 121 is, for example, about 17 μm to 18 μm, and the thickness of the first encapsulating wire 121 is, for example, about 3 μm.
[0030] After forming the first encapsulation line 121, the first photoresist film 201 is removed. Then, a second photoresist film 202 is formed on the substrate 100 and the upper surface of the first encapsulation line 121, and the second photoresist film 202 is patterned so that the upper surface of the first encapsulation line 121 in the region where the second encapsulation line 122 is to be formed is exposed, as shown in Figure 11. Next, as shown in Figure 12, the second encapsulation line 122 is formed on the upper surface of the first encapsulation line 121 that is exposed in the remaining region where the second photoresist film 202 has been formed. Specifically, a second lower metal layer 1221 is formed on the upper surface of the first encapsulation line 121, and a second upper metal layer 1222 is formed on the upper surface of the second lower metal layer 1221. For example, the second lower metal layer 1221 may be a Ni layer and the second upper metal layer 1222 may be an Au layer. The width of the second internal ligament 122 is, for example, about 10 μm, and the film thickness of the second internal ligament 122 is, for example, about 6 μm.
[0031] After removing the second photoresist film 202, a protrusion 11 is formed to connect with the first encapsulation line 121 and the second encapsulation line 122, as shown in Figure 13. For example, the protrusion 11 may be made of Rh material. To form the protrusion 11, a sacrificial layer may be formed on the upper surface of the substrate 100 corresponding to the portion of the protrusion 11 exposed from the base material 110, and the protrusion 11 may be formed using photolithography or the like so as to overlap with the ends of the first encapsulation line 121 and the second encapsulation line 122 and the sacrificial layer. After forming the protrusion 11, the sacrificial layer and the like are removed. As shown in Figure 13, by forming the second encapsulation line 122 in the region where the protrusion 11 and the encapsulation line 120 connect, the upper surface of the first encapsulation line 121 is exposed, thereby increasing the contact area between the protrusion 11 and the first encapsulation line 121.
[0032] After forming the protrusion 11, a third photoresist film 203 is formed on the upper surfaces of the substrate 100, the first inner lining 121, and the second inner lining 122. Then, the third photoresist film 203 is patterned to match the shape of the base material 110. As shown in Figure 14, the third photoresist film 203 is patterned to surround the first inner lining 121 and the second inner lining 122.
[0033] Next, as shown in Figure 15, the base material 110 is formed so as to embed the first internal lining 121 and the second internal lining 122. Specifically, the plating solution for the base material 110 is supplied from above between the third photoresist film 203 to form the base material 110. For example, the base material 110 may be a nickel alloy. After that, the third photoresist film 203 and the substrate 100 are removed to complete the probe 1.
[0034] The internal encapsulation line 120 of probe 1 has a narrower width for the second internal encapsulation line 122, which is formed later, than for the first internal encapsulation line 121, which is formed earlier. Therefore, there is a certain margin for alignment when stacking the second internal encapsulation line 122 on the first internal encapsulation line 121. This suppresses shape defects of probe 1 caused by misalignment between the first internal encapsulation line 121 and the second internal encapsulation line 122.
[0035] By the way, if the overall width of the inner wire 120 is increased and the film thickness is increased in order to lower the electrical resistance of the comparison probe 1M, the ratio of the distance between the third photoresist film 203 and the inner wire 120 in the width direction to the film thickness of the base material 110 (hereinafter also referred to as the "aspect ratio") becomes smaller. For example, if the film thickness of the upper metal layer 1232 of the comparison probe 1M is made to be about the same as the film thickness of the second upper metal layer 1222 of probe 1, the aspect ratio becomes smaller. Because the aspect ratio is small, when supplying the plating solution for forming the base material 110 from above between the third photoresist film 203 and the inner wire 120, the supply of the plating solution is hindered. As a result, a space 300 is created between the inner wire 120 and the third photoresist film 203, as shown in Figure 16.
[0036] As described above, increasing the overall film thickness of the inner wire 120 of the comparison probe 1M results in shape defects in the base material 110. On the other hand, narrowing the width of the inner wire 120 to suppress shape defects in the base material 110 hinders the reduction of the probe's electrical resistance.
[0037] Compared to the comparative probe 1M, the probe 1 according to the embodiment can achieve a larger aspect ratio in most of the stacking direction by increasing the film thickness of the relatively narrow second inner lining 122. Therefore, the supply of the plating solution for forming the base material 110 is not hindered, and the occurrence of shape defects in the base material 110 can be prevented. In probe 1, the electrical resistance is reduced by increasing the film thickness of the second upper metal layer 1222, which has particularly low electrical resistance among the second inner lining 122. Furthermore, the wide first inner lining 121 also contributes to the reduction of the electrical resistance of probe 1. Since the film thickness of the relatively wide first inner lining 121 is thin and it is located below the second inner lining 122, the supply of the plating solution for forming the base material 110 is not hindered.
[0038] As described above, according to the embodiment of the probe 1, the electrical resistance can be reduced because the internal wire 120, which has low electrical resistance, is continuous from the tip region connected to the protrusion 11 to the base region enclosed in the base end 30. Furthermore, because the internal wire 120 is continuous from the tip region to the base region, the internal wire 120 can be positioned away from the outer edge of the probe 1. As a result, plastic deformation of the probe 1 caused by stress applied during inspection of the object to be inspected is suppressed, and the mechanical strength of the probe 1 can be improved. Moreover, in the probe 1, the configuration in which a relatively wide first internal wire 121 and a relatively narrow and thick second internal wire 122 are stacked does not hinder the supply of the plating solution during the formation of the base material 110. As a result, according to the probe 1, the occurrence of shape defects in the base material 110 can be prevented, and the electrical resistance can be reduced by increasing the thickness of the internal wire 120.
[0039] 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.
[0040] For example, although the above description explained the case where the tip region of the inner wire 120 is connected to the protruding portion 11, the tip region of the inner wire 120 does not have to be connected to the protruding portion 11. If the tip region is located near the protruding portion 11, the electrical resistance from the protruding portion 11 to the base end portion 30 can be reduced.
[0041] Thus, the present invention naturally includes various embodiments not described above. 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]
[0042] 1 probe 10 Tip 11 Protrusion 20 Arms 30 Proximal end 40 Fixed part 110 Base material 120 Inner Enclosure 121 First Inner Enclosure 122 Second Inner Enclosure 1211 First lower metal layer 1212 First upper metal layer 1221 Second lower metal layer 1222 Second upper metal layer
Claims
1. A probe used for inspecting an object to be inspected, The protruding part, The base material connected to the aforementioned protruding portion, The internal wire embedded in the aforementioned base material, Equipped with, The aforementioned base material, The tip portion is embedded in such a way that the tip of the protruding portion protrudes toward the object to be inspected, Multiple arms, each with one end spaced apart from the others and connected to the tip, The other end of each of the aforementioned multiple arms is connected to a base end that is spaced apart from each other, Includes, The aforementioned internal line, The tip region enclosed within the aforementioned tip, Multiple arm regions are enclosed within the aforementioned multiple arms, with one end of each connected to the tip region, The base end region is enclosed within the base end and to which the other end of each of the plurality of arm regions is connected, including, probe.
2. The probe according to claim 1, wherein the tip region is connected to the protruding portion.
3. The probe according to claim 1, wherein the internal wire has lower electrical resistance than the base material.
4. The probe according to claim 1, wherein the hardness of the protruding portion is higher than the hardness of the base material and the internal lining.
5. The aforementioned internal line, It includes a first inner encapsulation line and a second inner encapsulation line that are stacked with the stacking direction being the normal direction of the plane defined by the direction in which the protruding portion protrudes and the extension direction of the arm, The film thickness along the lamination direction is such that the second inner layer is thicker than the first inner layer. The width perpendicular to the stacking direction is such that the first inner encapsulation line is wider than the second inner encapsulation line. The probe according to any one of claims 1 to 4.
6. The probe according to claim 5, wherein, in the arm, the second internal lining is positioned in the center of the base material when viewed from the stacking direction.
7. The first inner wire has a structure in which a first upper metal layer having lower electrical resistance than the first lower metal layer is laminated on a first lower metal layer. The second inner wire has a structure in which a second upper metal layer having lower electrical resistance than the second lower metal layer is laminated on a second lower metal layer. The second lower metal layer is laminated on the first upper metal layer. The thickness of the second upper metal layer is greater than the thickness of the first upper metal layer. The probe according to claim 6.
8. The material of the first lower metal layer and the second lower metal layer is nickel. The material of the first upper metal layer and the second upper metal layer is selected from the group consisting of gold, silver, and copper. The probe according to claim 7.