Probe

Abstract

This probe comprises a protruding part, a base material connected to the protruding part, and an enclosed line enclosed in the base material. The base material includes: a leading-end part in which the protruding part is embedded such that the leading end of the protruding part protrudes toward an object of inspection; a plurality of arms, respective parts of which at one end are separated from each other and connected to the leading-end part; and a base-end part to which respective parts at the other end of the plurality of arms are separated from each other and connected. The enclosed line includes: a leading-end region enclosed in the leading-end part; a plurality of arm regions enclosed in the plurality of arms and respective parts of which at one end are connected to the leading-end region; and a base-end region enclosed in the base-end part and to which respective parts at the other end of the plurality of arm regions are connected.

Description

Probe

[0001] The present invention relates to a probe used for inspecting the electrical characteristics of an object to be inspected.

[0002] In the inspection of an object to be inspected using a probe, one end of the probe (hereinafter referred to as the "tip end") is electrically connected to an inspection pad arranged on the surface of the object to be inspected, and the other end of the probe (hereinafter referred to as the "base end") is electrically connected to an inspection device such as a tester. A probe having a cantilever structure includes a tip end that is a free end, a base end that is a fixed end, and an arm that connects the tip end and the base end.

[0003] Japanese Patent Laid-Open No. 2007-303834

[0004] In order to accurately measure the electrical characteristics of an object to be inspected, 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.

[0005] According to one aspect of the present invention, there is provided a probe including a protruding portion, a base material connected to the protruding portion, and an inner wire encapsulated in the base material. The base material includes a tip portion in which the protruding portion is embedded such that the tip of the protruding portion protrudes toward the object to be inspected, a plurality of arms each having one end spaced apart from each other and connected to the tip portion, and a base end portion in which the other ends of the plurality of arms are spaced apart from each other and connected. The inner wire includes a tip region encapsulated in the tip portion, a plurality of arm regions encapsulated in the plurality of arms and each having one end connected to the tip region, and a base end region encapsulated in the base end portion and connected to the other ends of the plurality of arm regions.

[0006] According to the present invention, a probe having a low electrical resistance can be provided.

[0007] Figure 1 is a schematic diagram showing the configuration of a probe according to the embodiment. Figure 2 is a schematic diagram showing an enlarged view of the arm peripheral region A in Figure 1. Figure 3 is a cross-sectional view along the III-III direction in Figure 2. Figure 4 is a schematic diagram showing an enlarged view of the tip peripheral region B in Figure 1. Figure 5 is a cross-sectional view along the V-V direction in Figure 4. Figure 6 is a schematic diagram showing the inspection state using the probe according to the embodiment. Figure 7 is a schematic diagram showing the configuration of a probe of a comparative example. Figure 8 is a cross-sectional view along the VIII-VIII direction in Figure 7. Figure 9 is a schematic cross-sectional view (part 1) for explaining the manufacturing method of the probe according to the embodiment. Figure 10 is a schematic cross-sectional view (part 2) for explaining the manufacturing method of the probe according to the embodiment. Figure 11 is a schematic cross-sectional view (part 3) for explaining the manufacturing method of the probe according to the embodiment. Figure 12 is a schematic cross-sectional view (part 4) for explaining the manufacturing method of the probe according to the embodiment. Figure 13 is a schematic cross-sectional view (part 5) for explaining the manufacturing method of the probe according to the embodiment. Figure 14 is a schematic cross-sectional view (part 6) for explaining the manufacturing method of the probe according to the embodiment. Figure 15 is a schematic cross-sectional view illustrating a method for manufacturing a probe according to an embodiment (part 7). Figure 16 is a schematic cross-sectional view illustrating a problem that arises in the method for manufacturing a probe of a comparative example.

[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 Figure 1 is used for inspecting an object to be inspected. The probe 1 comprises a projection 11, a base material 110 connected to the projection 11, and an internal wire 120 enclosed within the base material 110. The base material 110 includes a tip 10, a plurality of arms 20, and a base end 30. A portion of the projection 11 is embedded in the tip 10 so that the tip of the projection 11 protrudes toward the object to be inspected. One end of each of the plurality of arms 20 is connected to the tip 10, spaced apart from each other. The other end of each of the plurality of arms 20 is connected to the base end 30, spaced apart from each other. The probe 1 is a cantilever structure in which a plurality of arms 20 are arranged in parallel, spaced apart from each other, between the tip 10, which is the free end, and the base end 30, which is the fixed end.

[0010] In describing the embodiment, the vertical direction in Figure 1 is referred to as the X direction, the horizontal direction as the Z direction, and the depth direction as the Y direction. For example, the direction in which the tip of the protruding portion 11 protrudes is the Z direction, and the multiple 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. The fixing portion 40 fixed to the probe head is electrically connected to an inspection device such as a tester, so that an electrical signal is transmitted between the inspection device and the object being inspected via the probe 1. For this reason, a highly conductive material such as metal may be used for the probe 1 through which the electrical signal is transmitted.

[0012] The internal wire 120 includes a tip region enclosed within the tip portion 10, multiple arm regions each enclosed within the multiple arms 20, and a base region enclosed within the base portion 30. The tip region of the internal wire 120 connects to the projection portion 11. One end of each of the multiple arm regions connects to the tip region. The other end of each of the multiple arm regions connects to the base region. In other words, the internal wire 120 is continuous from the tip region connected to the projection portion 11 to the base region enclosed within the base portion 30.

[0013] The internal casing 120 is covered by the base material 110 throughout all regions, including the tip region, arm region, and base region. In other words, as viewed from the normal direction (Y direction) of the XZ plane defined by the direction of projection of the protruding portion 11 (Z direction) and the extension direction of the arm 20 (X direction), the outer edge of the internal casing 120 is located inside the outer edge of the base material 110 throughout its entire range.

[0014] The internal encapsulation line 120 includes a first internal encapsulation line 121 and a second internal encapsulation line 122 stacked in the Y direction. Each of the first internal encapsulation line 121 and the second internal encapsulation line 122 is continuous from the tip region connected to the protruding portion 11 to the base region enclosed in the base portion 30. The direction in which the first internal encapsulation line 121 and the second internal encapsulation line 122 are stacked is also referred to as the "stacking direction". Hereinafter, the direction in which the second internal encapsulation line 122 is located as seen from the first internal encapsulation line 121 is defined as upward, and the direction in which the first internal encapsulation line 121 is located as seen from the second internal encapsulation line 122 is defined as downward. Also, the surface facing upward is defined as the top surface, and the surface facing downward is defined as the bottom surface.

[0015] As shown in Figure 2, which is an enlarged view of the arm peripheral region A in Figure 1, the second inner encapsulation line 122 is positioned inside the outer edge of the first inner encapsulation line 121 when viewed from the stacking direction. That is, the width in the Z direction perpendicular to the stacking direction is wider for the first inner encapsulation line 121 than for the second inner encapsulation line 122. Not limited to the arm region shown in Figure 2, the outer edge of the second inner encapsulation line 122 may be positioned inside the outer edge of the first inner encapsulation line 121 throughout the entire area of ​​the inner encapsulation line 120 when viewed from the stacking direction.

[0016] The cross-sectional structure of Figure 2 is shown in Figure 3. As shown in Figure 3, the thickness in the stacking direction (hereinafter also referred to as "film thickness") is such that the second inner encapsulation line 122 is thicker than the first inner encapsulation line 121. Because the width of the first inner encapsulation line 121 is wider than the width of the second inner encapsulation line 122, the cross-section of the inner encapsulation line 120 has a convex shape with the center of the upper surface raised.

[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 thickness of the second inner layer 122 is greater than that of the first inner layer 121. In particular, as shown in Figure 3, increasing the 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 protruding portion 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 protruding portion 11 is further pressed against the object to be inspected 2 while the protruding portion 11 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 2, 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. Therefore, even when a material with lower electrical resistance but lower yield strength (e.g., Au) is used for the second inner casing 122, which has a relatively thick film thickness, it is possible to suppress plastic deformation of probe 1 due to the stress applied during inspection of the object to be inspected 2.

[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 is made up 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 wire 120 of the arm 20 and the base end portion 30. As a result, an interface exists 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, the probe 1 shown in Figure 1 has an internal wire 120 that extends continuously from the protruding portion 11 to the base end portion 30. That is, the base material 110 is not interposed in the current path from the protruding portion 11 to the base end 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 end portion 30, each arm region of the internal wire 120 connects to the base end region. Thus, with probe 1, by extending the internal wire 120 continuously 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 end region, 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 drawings.

[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 lining 122 is, for example, about 10 μm, and the film thickness of the second internal lining 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 the 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 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 encapsulation line 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 encapsulation line 122. Furthermore, the wide first inner encapsulation line 121 also contributes to reducing the electrical resistance of probe 1. Since the film thickness of the relatively wide first inner encapsulation line 121 is thin and it is located below the second inner encapsulation line 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, the probe 1 prevents the occurrence of shape defects in the base material 110 and reduces electrical resistance 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.

[0042] 1 Probe 10 Tip 11 Projection 20 Arm 30 Base 40 Fixing part 110 Base material 120 Inner wire 121 First inner wire 122 Second inner wire 1211 First lower metal layer 1212 First upper metal layer 1221 Second lower metal layer 1222 Second upper metal layer

Claims

1. A probe for use in inspecting an object to be inspected, comprising: a protruding portion; a base material connected to the protruding portion; and an internal wire enclosed within the base material, wherein the base material includes: a tip portion into which the protruding portion is embedded such that the tip of the protruding portion protrudes toward the object to be inspected; a plurality of arms, each with one end spaced apart from the other and connected to the tip portion; and a base end portion into which the other ends of each of the plurality of arms are spaced apart from the other and connected, wherein the internal wire includes: a tip region enclosed within the tip portion; a plurality of arm regions enclosed within the plurality of arms, each with one end spaced apart from the tip region; and a base end region enclosed within the base end portion, to which the other ends of each of the plurality of arm regions are connected, the 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 or 2, wherein the internal wire has lower electrical resistance than the base material.

4. The probe according to any one of claims 1 to 3, wherein the hardness of the protruding portion is higher than the hardness of the base material and the internal wire.

5. The probe according to any one of claims 1 to 4, wherein the internal encapsulation wire includes a first internal encapsulation wire and a second internal encapsulation wire stacked with the stacking direction being the normal direction of a plane defined by the direction of protrusion of the protruding portion and the extension direction of the arm, the thickness of the second internal encapsulation wire along the stacking direction is thicker than that of the first internal encapsulation wire, and the width perpendicular to the stacking direction is wider for the first internal encapsulation wire than for the second internal encapsulation wire.

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 probe according to claim 6, wherein 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, and the film thickness of the second upper metal layer is thicker than the film thickness of the first upper metal layer.

8. The probe according to claim 7, wherein the material of the first lower metal layer and the second lower metal layer is nickel, and 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.

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