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

Cantilever-type probe for probe card and probe card

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

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

[0005] Patent No. 5060965

[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.

[0008] The cantilever-type probe for a probe card disclosed in the present application is a cantilever-type probe for a probe card, comprising: 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 and the tip portion, the base portion comprising a plurality of three-dimensional stress distribution portions which are recesses or protrusions along the longitudinal direction of the terminal portion. Also, the probe card disclosed in the present application is a probe card comprising: a cantilever-type probe for a probe card, comprising: 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 and the tip portion, the base portion comprising a plurality of three-dimensional stress distribution portions which are recesses along the longitudinal direction of the terminal portion, and the wiring board, the portion of the solder layer fixing the probe to the land of the wiring board formed within the stress distribution portion is cantilever-fixed to a solder end face joint formed between the land and the terminal portion of the probe by a solder layer covering a side surface of the base portion.

[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.

[0010] 1. A perspective view of a cantilever-type probe for a probe card according to a first embodiment. 2. A plan view of a portion surrounded by a dashed line in FIG. 1. 3. An A-A cross-sectional view of FIG. 2A. 4. 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 perpendicular to the longitudinal direction Z at the recess portion. 5. 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. 6. A perspective view of a cantilever-type probe for a probe card according to a second embodiment. 7. A plan view of a portion surrounded by a dashed line in FIG. 5. 8. 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 the recess portion. 9. A plan view of a main portion of a modified recess of a probe according to a third embodiment. 10. An F-F cross-sectional view of FIG. 8A. 11. A plan view of a main portion of a modified recess of a probe according to a fourth embodiment. 12. A G-G cross-sectional view of FIG. 11A. 13. A diagram showing a method for manufacturing a probe by pressing according to a fourth embodiment. 14. A plan view of a main portion of a protrusion of a probe according to a fifth embodiment. 15. An M-M cross-sectional view of FIG. 11A.

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

[0012] The probes 20 are components 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 disposed so that the beam portion 21B is substantially horizontal to the object to be inspected (an electronic circuit formed on a semiconductor wafer).

[0014] The 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 21. The 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 the terminal 21T, and an elastic deformation portion 21U that is located between the base 21D.

[0015] The elastically deforming portion 21U is formed with a single 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 portion surrounded by the dashed line in Fig. 1. It is a view of 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 is composed of two types of metals with different resistivities. One is an inner metal (first metal) that constitutes the low-resistance portion L, which is 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, which has a higher resistivity and lower conductivity than the low-resistance portion L, but has high mechanical strength and springiness, such as a palladium-cobalt (PdCo) alloy. The high-resistance portion H functions to maintain the mechanical strength of the probe 20.

[0019] 1, 2A, and 2B, a plurality of rectangular prism-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, a tin alloy layer 21Sn is formed from a position on the terminal portion 21T side of a line segment B connecting the upper ends of the recesses 21R and above a line segment C connecting the lower ends thereof, as shown in Fig. 2A, so as to cover the entire terminal portion 21T side. By melting this tin alloy layer 21Sn, the probe 20 is fixed to a land of the wiring board.

[0020] 3 is a cross-sectional view taken perpendicular to the longitudinal direction Z at the recess 21R in the vicinity of the terminal portion 21T of the probe 20 soldered to the land Ln of the wiring board K. When the terminal portion 21T of the probe 20 is pressed against the land Ln of the wiring board K and the tin alloy layer 21Sn is heated, the molten tin alloy follows the inner wall surface of the recess 21R and solidifies into a fillet shape together with the tin alloy layer 21Sn formed in 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), and 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 by 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 for creating fine three-dimensional structures using photolithography and sacrificial layer etching. Photolithography is a technology for processing fine patterns using photoresist, which is used in semiconductor manufacturing processes, etc. Sacrificial layer etching is a technology for creating 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 an electrolyte, a drying process is performed after the plating process. After the drying process, the needle tip 22 is polished by a polishing process.

[0026] Specifically, first, the lower layer 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 lower surface 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 tin alloy layer 21Sn is formed by immersing the above-mentioned predetermined range from the terminal portion 21T into the molten tin alloy. Since a plurality of recesses 21R are formed in the longitudinal direction Z of the base portion 21D near the terminal portion 21T, it is possible to prevent the tin alloy layer 21Sn 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 heat is applied to melt the tin alloy layer 21Sn, 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 run up above the base portion 21D. As shown in Fig. 3, the cross-sectional shape of the tin alloy layer 21Sn after adhering sandwiches the terminal portion 21T in the vertical direction, but the recess 21R does not penetrate in the stacking direction R of the probe 20. 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 with no variation in bonding quality of probe 20 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. A cantilever-type probe for a probe card and a probe card according to embodiment 2 will be described below, focusing on the differences from embodiment 1. Fig. 5 is a perspective view of a cantilever-type probe 20 for a probe card according to embodiment 2 (hereinafter simply referred to as probe 20). It is a perspective view of a probe card (not shown) before attachment to a wiring board K. Fig. 6 is a plan view of the portion surrounded by the dashed line in Fig. 5. It is a view of the vicinity of the terminal portion 21T side of pedestal portion 21D as seen in the thickness direction Y of probe 20. Fig. 7 is a cross-sectional view of the vicinity of terminal portion 21T of probe 20 soldered to land Ln of wiring board K, taken perpendicular to the longitudinal direction Z at recess 21R.

[0036] In the first embodiment, an example was shown in which a plurality of rectangular prism-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 second embodiment, they are formed in two rows along the longitudinal direction Z. Also, in the second embodiment, the range in which the tin alloy layer 21Sn is formed is the region on the terminal portion 21T side from between line segments D and E in Fig. 6. Line segment D is a line segment connecting the upper ends of the row of depressions 21R on the tip portion 22 side, and 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 multiple rows of recesses 21R are provided in the longitudinal direction Z, if a tin alloy layer 21Sn is formed to cover at least a portion of the inside of the uppermost recess 21R (near the needle tip portion 22), the same effect as in embodiment 1 can be achieved.

[0038] Embodiment 3. A cantilever-type probe for a probe card and a probe card according to embodiment 3 will be described below, focusing on the differences from embodiment 1. Fig. 8A is a plan view of a main part of a modified example of recess 21R of probe 20. It is a view of the vicinity of terminal portion 21T side of pedestal portion 21D as seen in the plate thickness direction Y of probe 20. Fig. 8B is a cross-sectional view taken along 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. A cantilever-type probe for a probe card and a probe card according to embodiment 4 will be described below, focusing on the differences from embodiment 1. Fig. 9A is a plan view of a main part of a modified example of recess 21R of probe 20. It is a view of the vicinity of terminal portion 21T side of pedestal portion 21D as seen in the plate thickness direction Y of probe 20. Fig. 9B is a cross-sectional view taken along line G-G in Fig. 9A.

[0042] Although the above description has been given of an example in which the rectangular prism-shaped recess 21R is provided in the vicinity of the terminal portion 21T side of the base portion 21D, the recess 21R may be a dimple-shaped recess, i.e., a hemispherical recess. However, this shape cannot be formed by laminating metal layers, so it is formed by press working.

[0043] 10 is a diagram showing a method for manufacturing the probe 20 by pressing. The probe 20, in which high resistance portions H and H are stacked, is pressed from both sides using a first mold 51 and a second mold 52 having hemispherical protrusions corresponding to the respective depressions 21R, to form the hemispherical depressions 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. The recess 21R may also 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 , 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. A cantilever-type probe for a probe card and a probe card according to embodiment 5 will be described below, focusing on the differences from embodiment 1. Fig. 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. It is a view of the vicinity of terminal portion 21T side of base portion 21D as viewed in the plate thickness direction Y of probe 20. Fig. 11B is a cross-sectional view taken along line M-M in Fig. 11A. Up to this point, recess 21R has been described as the stress dispersion part, but as shown in Figs. 11A and 11B, the stress dispersion part may also be protrusion 21P.

[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 various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology disclosed in this application. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0049] 20 Cantilever type probe for probe card, 10 Ridge line, 10B Vertex, 21 Main body portion, 21B Beam portion, 21D Base portion, 21DS Surface, 21R Depression, 21Sn Tin alloy layer, 21Sout Solder layer, 21T Terminal portion, 21TS End face joint portion, 21U Elastic deformation portion, 21UH Slot, 22 Needle tip portion, 21P Protrusion portion, 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, comprising: a pedestal portion rising upward from a terminal portion connected to a wiring board, a tip portion, and a beam portion between the pedestal portion and the tip portion; The pedestal portion is spaced apart from the end face on the wiring board side and along the longitudinal direction of the terminal portion, and the pedestal portion is provided with a plurality of three-dimensional stress dispersion portions which are non-penetrating depressions or protrusions in the thickness direction of the pedestal portion. A cantilever type probe for a probe card.

2. The cantilever type 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 pedestal portion.

3. The cantilever type 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 pedestal portion.

4. The cantilever type probe for a probe card according to claim 1, wherein the stress dispersion portion is any one of a polygonal prism shape, a frustum of a polygonal pyramid shape, a cylindrical shape, a hemispherical shape, and a frustum of a cone shape.

5. The probe comprises a low-resistance portion made of a metal layer having low electrical resistance, and on the outside of the low-resistance portion, a high-resistance portion having higher electrical resistance than the low-resistance portion and having spring properties. The cantilever type probe for a probe card according to any one of claims 1 to 4, wherein the stress dispersion portion is formed in the high-resistance portion.

6. The cantilever type probe for a probe card according to claim 5, wherein the stress dispersion portion is a depression penetrating the high-resistance portion in the thickness direction of the pedestal portion.

7. A cantilever type probe for a probe card, comprising a pedestal portion rising upward from a terminal portion connected to a wiring board, a tip portion, and a beam portion between the pedestal portion and the tip portion, and a probe card comprising the wiring board, wherein the pedestal portion is spaced apart from the end face on the wiring board side and along the longitudinal direction of the terminal portion, and the pedestal portion is provided with a plurality of three-dimensional stress dispersion portions which are non-penetrating depressions in the thickness direction of the pedestal portion, In the solder layer fixing the probe to the land of the wiring board, the portion formed in the stress dispersion portion is fixed in a cantilever manner by a solder layer covering the side surface of the pedestal portion with respect to the solder end face joint portion formed between the land and the terminal portion of the probe. A probe card.

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