Cantilever-type probe for probe card and probe card

Abstract

A cantilever-type probe (20) for a probe card comprises: a base (21D) that stands upright from a terminal (21T) that connects to a wiring substrate (K); a needle tip section (22); and a beam (21B) that is located between the base (21D) and the needle tip section (22). The base (21D) is provided with, along the longitudinal direction (Z) of the terminal (21T), a plurality of three-dimensional stress dissipating parts which are recesses (21R) or protrusions (21P).

Description

[Technical Field]

[0001] The present application relates to a cantilever-type probe for a probe card and a probe card. [Background technology]

[0002] A probe card is an electrical connection device used to supply power, input / output signals, and ground the semiconductor devices by contacting probes with the electrode pads of the semiconductor devices in order to perform operational tests of the individual semiconductor devices formed on a wafer. The probes are provided on the surface of the probe card, and are configured so that their tips are pressed against the electrode pads of the semiconductor device with a predetermined pressure.

[0003] In order to increase the number of semiconductor devices formed on a wafer, it is necessary to reduce the size of the semiconductor devices. To this end, the electrode pads of semiconductor devices are designed to be small, and the distance between the electrode pads (pitch) is also designed to be small. Therefore, as semiconductor devices become smaller, probes must also be made finer. However, making probes finer reduces the mechanical strength when soldering terminals to lands on the probe substrate.

[0004] For this reason, a probe has been proposed in which a through hole is drilled near the end face of the connection part of the probe body to the land, and the molten solder is guided through this part to the other side (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5060965 Summary of the Invention [Problem to be solved by the invention]

[0006] When soldering a probe to a land on a probe board, stress acts around the joint at the base of the probe due to the contraction of the solidifying solder. If a through hole is provided at the end of the probe, the fixing force is strong, but there is a problem in that excessive stress is concentrated around the hole.

[0007] The present application discloses a technology for solving the above-mentioned problems, and aims to provide a cantilever-type probe for a probe card and a probe card that have an appropriate adhesive strength when soldered to a land on a probe substrate, even when the probe is made fine, and that can distribute the stress generated at the base of the probe when the solder shrinks. [Means for solving the problem]

[0008] The cantilever probe for a probe card disclosed in the present application comprises: A cantilever-type probe for a probe card, The probe includes a base portion rising upward from a terminal portion connected to a wiring board, a tip portion, and a beam portion located between the base portion and the tip portion, The base portion is Away from the end face on the wiring board side Along the longitudinal direction of the terminal portion The base portion is formed in a non-penetrating manner in the thickness direction of the base portion. It is provided with a plurality of three-dimensional stress dispersion portions which are depressions or protrusions. The probe card disclosed in the present application also includes: a cantilever-type probe for a probe card, the cantilever-type probe including a base portion rising upward from a terminal portion connected to a wiring board, a needle tip portion, and a beam portion located between the base portion and the needle tip portion; A probe card including the wiring substrate, The base portion is Away from the end face on the wiring board side Along the longitudinal direction of the terminal portion The base portion is formed in a non-penetrating manner in the thickness direction of the base portion. a plurality of three-dimensional stress dispersion portions that are depressions; The solder layer that fixes the probe to the land of the wiring board has a portion formed within the stress distribution section that is cantilevered and fixed to the solder end face joint formed between the land and the terminal portion of the probe by the solder layer that covers the side of the base section. [Effects of the Invention]

[0009] According to the cantilever-type probe for a probe card and the probe card disclosed in the present application, it is possible to provide a probe for a probe card that has an appropriate adhesive strength when soldered to a land on a probe substrate, even if the probe is made fine, and that can distribute the stress generated at the base of the probe when the solder shrinks. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of a cantilever probe for a probe card according to a first embodiment. FIG. [Figure 2A] FIG. 2 is a plan view of the portion surrounded by the dashed line in FIG. [Figure 2B] 2B is a cross-sectional view taken along the line AA in FIG. 2A. [Figure 3] 1 is a cross-sectional view of the vicinity of a terminal portion of a probe soldered to a land of a wiring board according to the first embodiment, taken perpendicularly to the longitudinal direction Z at a recessed portion. [Figure 4] 2 is a cross-sectional view showing a state in which a sacrificial layer is disposed to form a recess in the portion surrounded by the dashed line in FIG. 1. FIG. [Figure 5] FIG. 10 is a perspective view of a cantilever probe for a probe card according to a second embodiment. [Figure 6] FIG. 6 is a plan view of the portion surrounded by the dashed line in FIG. 5. [Figure 7] 1 is a cross-sectional view of the vicinity of a terminal portion of a probe soldered to a land of a wiring board, taken perpendicular to the longitudinal direction Z at a recessed portion. [Figure 8A] FIG. 11 is a plan view of a main part of a modified example of a recess of a probe according to the third embodiment. [Figure 8B] FIG. 8B is a cross-sectional view of FIG. 8A shown in FIG. 8A. [Figure 9A] FIG. 11 is a plan view of a main part of a modified example of a recess of a probe according to the fourth embodiment. [Figure 9B] GG cross-sectional view of FIG. 9A. [Figure 10]10A and 10B are diagrams illustrating a method for manufacturing a probe by pressing according to a fourth embodiment. [Figure 11A] FIG. 11 is a plan view of a main part of a protrusion of a probe according to a fifth embodiment. [Figure 11B] 11B is a cross-sectional view of FIG. 11A taken along line MM. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiment 1 Hereinafter, the cantilever-type probe for a probe card and the probe card according to the first embodiment will be described with reference to the drawings. 1 is a perspective view of a cantilever-type probe 20 for a probe card (hereinafter simply referred to as probe 20) according to embodiment 1. This is a perspective view of the probe card before it is attached to a wiring substrate (not shown). 1 will be referred to as "top" and "bottom." The direction in which the probe 20 buckles (elastically deforms) during overdrive is referred to as the buckling direction X, and the direction perpendicular to the buckling direction X, which is the thickness direction of the probe 20, i.e., the direction in which metal films are laminated during the manufacture of the probe 20, is referred to as the plate thickness direction Y. The longitudinal direction of the terminal portion 21T of the probe 20 is referred to as the longitudinal direction Z.

[0012] The probe 20 is a component used in a probe card (not shown). The probe card is a device used to test the electrical characteristics of electronic circuits formed on a semiconductor wafer. The characteristic test of the electronic circuit is performed by bringing the semiconductor wafer close to the probe card, contacting the tips of the probes 20 with electrodes on the electronic circuit, and establishing electrical continuity between a tester device and tester connection electrodes on the wiring board of the probe card via the probes 20.

[0013] The probe 20 is a cantilever-type probe that is placed so that the beam portion 21B is approximately horizontal to the object to be inspected (an electronic circuit formed on a semiconductor wafer).

[0014] Probe 20 has a thin plate-shaped main body 21 and a probe tip 22 that protrudes upward from the upper end of the main body. Main body 21 includes a terminal 21T that is connected to a wiring land of a wiring board (not shown) that is located below the paper surface of FIG. 1, a base 21D that rises upward from terminal 21T, and an elastic deformation portion 21U that is located between base 21D.

[0015] The elastically deforming portion 21U is formed with one elongated hole 21UH that extends in the longitudinal direction Z and penetrates in the plate thickness direction Y, and the elongated hole 21UH divides the elastically deforming portion 21U into two beam portions 21B. Note that although an example in which the probe 20 includes two beam portions 21B is shown in FIG. 1, the number of beam portions 21B may be one, or three or more.

[0016] When the probe 20 is overdriven, a compressive force is applied in the vertical direction in FIG. 1, and the probe 20 easily undergoes buckling deformation in the buckling direction X in response to a reaction force from the test object.

[0017] Fig. 2A is a plan view of the area surrounded by the dashed line in Fig. 1. The view shows the vicinity of the terminal portion 21T side of the base portion 21D as viewed in the plate thickness direction Y of the probe 20. FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A.

[0018] The probe 20 is conductive and composed of two types of metals with different resistivities. One is an inner metal (first metal) that constitutes the low-resistance portion L, made of a metal with low resistivity such as copper, gold, or silver (Cu, Au, Ag). The low-resistance portion L has high conductivity and functions to improve current resistance. The other is an outer metal (second metal) that constitutes the high-resistance portion H, made of a palladium-cobalt (PdCo) alloy or the like, which has higher resistivity and lower conductivity than the low-resistance portion L, but has high mechanical strength and springiness. The high-resistance portion H functions to maintain the mechanical strength of the probe 20.

[0019] 1, 2A, and 2B, a plurality of rectangular pillar-shaped recesses 21R are formed in a row along the longitudinal direction Z near the terminal portion 21T on both surfaces 21DS of the base portion 21D of the probe 20 in the plate thickness direction Y. Then, as shown in Fig. 2A, a tin alloy layer 21Sn is formed from a position closer to the terminal portion 21T than line segment B connecting the upper ends of the recesses 21R and above line segment C connecting the lower ends so as to cover the entire terminal portion 21T side. By melting this tin alloy layer 21Sn, the probe 20 is fixed to the land of the wiring board.

[0020] FIG. 3 is a cross-sectional view of the vicinity of the terminal portion 21T of the probe 20 soldered to the land Ln of the wiring board K, taken perpendicular to the longitudinal direction Z at the portion of the recess 21R. When the terminal portion 21T of the probe 20 is pressed against the land Ln of the wiring substrate K and the tin alloy layer 21Sn is heated, the molten tin alloy conforms to the inner wall surface of the recess 21R and solidifies into a fillet shape together with the tin alloy layer 21Sn formed on other parts including the end face of the terminal portion 21T.

[0021] This depression 21R is formed in the high resistance portion H. Here, for the probe 20 in which the rectangular prism-shaped depression 21R is arranged, the stress after soldering was calculated based on the finite element method (FEM). As a result, it was found that the stress of the solder that melts and then solidifies is concentrated at each vertex 10B of the depression 21R shown in FIG. 2B and at the ridge 10 formed by the two adjacent faces that make up the depression 21R.

[0022] In this way, by arranging the rectangular prism-shaped depressions 21R as stress distribution portions evenly in the longitudinal direction Z on the base portion 21D of the probe 20, the stress acting on the fixed portion due to soldering can be evenly distributed to each vertex 10B and each ridge 10 of the depressions 21R.

[0023] Fig. 4 is a cross-sectional view showing a state in which a sacrificial layer G is disposed to form a recess 21R in the area surrounded by the dashed line in Fig. 1. The lamination direction R indicates the lamination direction of the metal layers during manufacturing.

[0024] The probe 20 is fabricated using so-called MEMS (Micro Electro Mechanical Systems) technology. MEMS technology is a technology that uses photolithography technology and sacrificial layer etching technology to create fine three-dimensional structures. Photolithography technology is a fine pattern processing technology that uses photoresist, which is used in semiconductor manufacturing processes, etc. Sacrificial layer etching technology is a technology that creates a three-dimensional structure by forming a lower layer called a sacrificial layer G, forming layers that constitute the structure on top of it, and then removing only the sacrificial layer G by etching.

[0025] Well-known plating techniques can be used to form the high resistance portion H and the low resistance portion L. For example, by immersing a substrate as a cathode and a metal piece as an anode in an electrolyte and applying a voltage between the two electrodes, metal ions in the electrolyte can be attached to the surface of the substrate. This type of process is called electroplating, and since it is a wet process in which the substrate is immersed in the electrolyte, a drying process is performed after the plating process. Then, after the drying process, the needle tip portion 22 is polished by a polishing process.

[0026] Specifically, first, the lower high resistance portion H shown in FIG. 2B is formed excluding the portion corresponding to the recess 21R. Next, the high resistance portion H is formed above the lower recess 21R and below the low resistance portion L. Next, the low resistance portion L is formed. Next, the high resistance portion H shown in FIG. 2B is formed above the low resistance portion L and below the underside of the upper recess 21R. Next, the high resistance portion H is formed on top of that, excluding the upper recess 21R in FIG. 2B.

[0027] Then, the above-mentioned predetermined range from the terminal portion 21T is immersed in the molten tin alloy to form the tin alloy layer 21Sn. A plurality of recesses 21R are formed in the longitudinal direction Z of the base portion 21D near the terminal portion 21T, so that the tin alloy layer 21Sn can be prevented from running up beyond the recesses 21R. In addition, the tin alloy layer 21Sn may be formed by plating the tin alloy layer 21Sn with a mask applied to the outer periphery other than the portion where the tin alloy layer 21Sn is to be formed.

[0028] Thereafter, the terminal portion 21T of the probe 20 on which the tin alloy layer 21Sn is formed is pressed against the land Ln of the wiring board K, and the tin alloy layer 21Sn is melted by applying heat, thereby soldering the probe 20 to the land Ln.

[0029] The molten tin alloy layer 21Sn (solder) adheres to the inner wall surface of the recess 21R as shown in FIG. 3. Furthermore, it does not extend beyond the upper surface of the recess 21R and climb upward above the base portion 21D. As shown in FIG. 3, the cross-sectional shape of the adhered tin alloy layer 21Sn sandwiches the terminal portion 21T in the vertical direction, but the recess 21R does not penetrate the probe 20 in the stacking direction R. Therefore, excessive stress is not applied to the terminal portion 21T due to contraction when the solder solidifies. Furthermore, since stress can be distributed among multiple recesses 21R, stable bonding of the probe 20 is possible.

[0030] In this embodiment, an example in which two types of metals are used for the high resistance portion H and the low resistance portion L has been shown, but they may be manufactured using one type of metal.

[0031] According to the cantilever-type probe for a probe card and the probe card of embodiment 1, the stress generated inside the probe 20 when soldering to the land Ln of the wiring board K can be evenly distributed to each vertex 10B and each ridge 10 of the recess 21R, thereby providing a cantilever-type probe for a probe card with high mechanical strength.

[0032] Furthermore, recess 21R can prevent solder from running up during bonding, so that a cantilever-type probe for a probe card and a probe card in which the bonding quality of probe 20 is consistent can be provided.

[0033] Furthermore, the recess 21R can accommodate excess solder, preventing the fillet shape from spreading excessively laterally.

[0034] Furthermore, after the solder is fixed, the portion 21Sin formed in the recess 21R is fixed in a cantilever manner to the end face joint portion 21TS, which is the solder fixing layer formed between the land Ln and the terminal portion 21T, by the solder layer 21Sout covering the side surface of the base portion 21D, so that the solder is flexible, durable, and does not peel off.

[0035] Embodiment 2 The cantilever-type probe for a probe card and the probe card according to the second embodiment will be described below, focusing on the differences from the first embodiment. 5 is a perspective view of a cantilever-type probe 20 for a probe card (hereinafter simply referred to as probe 20) according to embodiment 2. This is a perspective view of the probe card before it is attached to a wiring board K (not shown). Fig. 6 is a plan view of the part surrounded by the dashed line in Fig. 5. The view shows the vicinity of the terminal portion 21T side of the base portion 21D as viewed in the plate thickness direction Y of the probe 20. FIG. 7 is a cross-sectional view of the vicinity of the terminal portion 21T of the probe 20 soldered to the land Ln of the wiring board K, taken perpendicular to the longitudinal direction Z at the recess 21R.

[0036] In the first embodiment, an example was shown in which a plurality of rectangular pillar-shaped depressions 21R were formed in a row along the longitudinal direction Z near the terminal portion 21T on both surfaces 21DS of the base portion 21D of the probe 20 in the plate thickness direction Y, but in the present embodiment, they are formed in two rows along the longitudinal direction Z, which is different. Also, in the second embodiment, the range in which the tin alloy layer 21Sn is formed is the region between the line segments D and E in Fig. 6 on the terminal portion 21T side. The line segment D is a line segment connecting the upper ends of the row of depressions 21R on the tip portion 22 side, and the line segment E is a line segment connecting the lower ends of the same row on the terminal portion 21T side.

[0037] In this way, when the recesses 21R are provided in multiple rows in the longitudinal direction Z, the same effect as in embodiment 1 can be achieved by forming a tin alloy layer 21Sn so as to cover at least a portion of the inside of the uppermost recess 21R (near the tip portion 22).

[0038] Embodiment 3 The cantilever-type probe for a probe card and the probe card according to the third embodiment will be described below, focusing on the differences from the first embodiment. 8A is a plan view of a main part of a modified example of recess 21R of probe 20. This is a view of the vicinity of terminal portion 21T side of base portion 21D as viewed in thickness direction Y of probe 20. FIG. 8B is a cross-sectional view taken along the line F-F of FIG. 8A.

[0039] In the first embodiment, the recess 21R does not penetrate the high resistance portion H perpendicular to the buckling direction X, but in the second embodiment, the recess 21R penetrates the high resistance portion H perpendicular to the buckling direction X.

[0040] Even with this configuration, the same effects as in the first embodiment can be achieved. In this way, the depth of the recess 21R may be changed according to the required mechanical strength. Also, the recess may penetrate only the high resistance portion H. In this case, the number of manufacturing steps for the probe 20 can be reduced.

[0041] Embodiment 4 The cantilever-type probe for a probe card and the probe card according to the fourth embodiment will be described below, focusing on the differences from the first embodiment. 9A is a plan view of a main part of a modified example of recess 21R of probe 20. This is a view of the vicinity of terminal portion 21T side of base portion 21D as viewed in thickness direction Y of probe 20. FIG. 9B is a cross-sectional view taken along line GG in FIG. 9A.

[0042] So far, we have described an example in which the rectangular prism-shaped recess 21R is provided near the terminal portion 21T side of the base portion 21D, but the recess 21R may also be a dimple-shaped, i.e., a hemispherical recess. However, this shape cannot be formed by laminating metal layers, so it is formed by press working.

[0043] FIG. 10 is a diagram showing a method for manufacturing the probe 20 by pressing. The high resistance portion H and the second mold 52 are formed by a first mold 51 and a second mold 52 having hemispherical protrusions corresponding to the respective recesses 21R. low Resistance part L The probe 20, which is made by laminating these, is pressed from both sides to form a hemispherical depression 21R on the surface.

[0044] In this case, there is an advantage that the manufacturing time can be shortened compared to forming a metal layer by electroforming. Furthermore, the recess 21R may be in the shape of a polygonal pillar, a polygonal truncated pyramid, a cylinder, or a truncated cone. Recesses 21R of these shapes can also be manufactured by pressing. After forming the recess 21R, a tin alloy layer 21Sn is formed in the above-mentioned predetermined range (in FIG. 10, on the terminal portion 21T side from the line segment J).

[0045] The cantilever probe for a probe card and the probe card according to the fourth embodiment have the same effects as those of the first embodiment.

[0046] Embodiment 5. The cantilever-type probe for a probe card and the probe card according to the fifth embodiment will be described below, focusing on the differences from the first embodiment. 11A is a plan view of a main part of protrusion 21P which is a modified example of the stress dispersion part of probe 20. The view shows the vicinity of terminal portion 21T side of base portion 21D as viewed in thickness direction Y of probe 20. FIG. 11B is a cross-sectional view taken along line MM of FIG. 11A. So far, recesses 21R have been described as stress dispersing portions, but as shown in FIGS. 11A and 11B, protrusions 21P may also serve as stress dispersing portions.

[0047] The cantilever probe for a probe card and the probe card according to the fifth embodiment have the same effects as those of the first embodiment.

[0048] Although the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are conceivable within the scope of the technology disclosed in this application, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with a component of another embodiment. [Explanation of symbols]

[0049] 20 Cantilever type probe for probe card, 10 Ridge line, 10B Vertex, 21 Main body, 21B Beam, 21D Base, 21DS Surface, 21R Depression, 21Sn Tin alloy layer, 21Sout Solder layer, 21T Terminal, 21TS End face joint, 21U Elastic deformation portion, 21UH Slot, 22 Needle tip, 21P Protrusion, 51 First mold, 52 Second mold, G Sacrificial layer, H High resistance portion, L Low resistance portion, Ln Land, R Stacking direction, X Buckling direction, Y Plate thickness direction, Z Longitudinal direction, K Wiring board.

Claims

1. A cantilever-type probe for a probe card, The probe includes a base portion rising upward from a terminal portion connected to a wiring board, a tip portion, and a beam portion located between the base portion and the tip portion, The base portion is spaced apart from the end face on the wiring substrate side and extends along the longitudinal direction of the terminal portion, and the base portion is provided with a plurality of three-dimensional stress distribution portions which are non-penetrating recesses or protrusions in the thickness direction of the base portion.

2. 2. The cantilever probe for a probe card according to claim 1, wherein the stress dispersion portions are arranged in a row along the longitudinal direction of the base portion.

3. 2. The cantilever probe for a probe card according to claim 1, wherein the stress dispersion portions are arranged in a plurality of rows along the longitudinal direction of the base portion.

4. 2. The cantilever probe for a probe card according to claim 1, wherein the stress dispersion portion has any one of a polygonal prism shape, a polygonal truncated pyramid shape, a cylindrical shape, a hemisphere shape, and a circular truncated cone shape.

5. The probe includes a low resistance portion made of a metal layer having a low electrical resistance; a high resistance portion having a higher electrical resistance than the low resistance portion and having spring properties, the high resistance portion being disposed outside the low resistance portion; 5. The cantilever-type probe for a probe card according to claim 1, wherein the stress dispersion portion is formed in the high resistance portion.

6. 6. The cantilever-type probe for a probe card according to claim 5, wherein the stress dispersion portion is a recess that penetrates the high resistance portion in the thickness direction of the base portion.

7. a cantilever-type probe for a probe card, the cantilever-type probe including a base portion rising upward from a terminal portion connected to a wiring board, a needle tip portion, and a beam portion located between the base portion and the needle tip portion; A probe card including the wiring substrate, the base portion includes a plurality of three-dimensional stress dispersion portions, which are recesses that do not penetrate the base portion in a thickness direction, spaced apart from the end surface on the wiring substrate side and along a longitudinal direction of the terminal portion, A probe card in which the solder layer that fixes the probe to the land of the wiring board is fixed in a cantilever manner by the solder layer covering the side of the base portion to the solder end face joint formed between the land and the terminal portion of the probe, the portion formed within the stress distribution portion.

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