Cantilever probe for probe card and probe card

Abstract

A cantilever probe (20) for a probe card is provided with: a base section (21D) that rises upward from a terminal section (21T) connected to a wiring board (K); a needle tip part (22); and a beam portion (21B) located between the base portion (21D) and the needle tip portion (22), the base portion (21D) includes a plurality of three-dimensional stress dispersion portions along the longitudinal direction (Z) of the terminal portion (21T), and the stress dispersion portions are recessed portions (21R) or protruding portions (21P).

Description

Technical Field

[0001] The present application relates to a cantilever probe for a probe card and the probe card. Background Art

[0002] The probe card is an electrical connection device used to contact the electrode pads of the semiconductor device with probes to supply power, input and output signals, and connect ground to perform an operation test of each semiconductor device formed on a wafer. The probes are provided on the surface of the probe card, and are configured so that the tips thereof are pressed against the electrode pads of the semiconductor device with a predetermined pressing force.

[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. Therefore, the electrode pads of the semiconductor devices are designed to be smaller, and the distance (pitch) between the electrode pads is designed to be smaller. Therefore, corresponding to the miniaturization of the semiconductor devices, it is necessary to make the probe finer. However, when the probe is made finer, there is a problem that the mechanical strength is weakened when the terminal portion is welded to the pad provided on the probe substrate.

[0004] Therefore, a probe has been proposed in which a hole is opened in the end surface of a connection portion to a pad of a probe body and penetrates to the vicinity, and molten solder is guided to the other side through this portion (see, for example, Patent Document 1). Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent No. 5060965 Summary of the invention Technical problem to be solved by the invention

[0006] When the probe is soldered to the pad provided on the probe substrate, stress acts on the joint periphery of the root of the probe due to the contraction of the solidified solder. When the through hole is provided at the end of the probe, the fixing force is strong, but there is a technical problem that stress is excessively concentrated around the hole.

[0007] The present application discloses a technology for solving the above-mentioned problems, and its purpose is to provide a cantilever probe for a probe card and a probe card which has a moderate fixing force when soldering to a pad of a probe substrate even if the probe is made fine and can disperse the stress generated at the base of the probe when the solder shrinks. Technical solutions adopted to solve technical problems

[0008] The cantilever probe for a probe card disclosed in the present application is a cantilever probe for a probe card, which includes: A base portion rising upward from a terminal portion connected to a wiring substrate; a needle tip portion; and a beam portion located between the base portion and the needle tip portion, The base portion includes a plurality of three-dimensional stress dispersion portions along a length direction of the terminal portion, and the stress dispersion portions are recesses or protrusions. In addition, the probe card disclosed in the present application includes: A cantilever probe for a probe card, the cantilever probe for a probe card comprising a base portion rising upward from a terminal portion connected to a wiring substrate, a needle tip portion, and a beam portion located between the base portion and the needle tip portion; and The wiring substrate, The base portion includes a plurality of three-dimensional stress dispersion portions along the length direction of the terminal portion, wherein the stress dispersion portions are recessed. In the solder layer fixing the probe to the pad of the base plate, a portion formed in the stress dispersion portion is fixed relative to the solder end surface joint formed between the pad and the terminal portion of the probe by the solder layer cantilever covering the side surface of the base portion. Effects of the Invention

[0009] According to the cantilever probe for a probe card and the probe card disclosed in the present application, a probe for a probe card can be provided which has an appropriate bonding strength when soldered to a pad of a probe substrate even if the probe is made fine and can disperse the stress generated at the base of the probe when the solder shrinks. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a perspective view of a cantilever probe for a probe card according to the first embodiment. Figure 2A yes Figure 1 A top view of the portion surrounded by a dotted line. Figure 2B yes Figure 2A AA section view. Figure 3 This is a cross-sectional view of the vicinity of the terminal portion of the probe bonded to the pad of the wiring board according to the first embodiment cut perpendicularly with respect to the longitudinal direction Z at a recessed portion. Figure 4 is a diagram showing the configuration of the sacrificial layer to produce Figure 1 A cross-sectional view showing a depressed state of a portion surrounded by a dotted line. Figure 5 This is a perspective view of a cantilever probe for a probe card according to a second embodiment. Figure 6 yes Figure 5 A top view of the portion surrounded by the dotted line. Figure 7This is a cross-sectional view obtained by cutting the vicinity of the terminal portion of the probe soldered to the pad of the wiring board perpendicularly with respect to the longitudinal direction Z at a recessed portion. Fig. 8A It is a cross-sectional view of a main part of a modified example of the recess of the probe of the third embodiment. Figure 8B yes Fig. 8A FF cross-sectional view. Fig.9A It is a cross-sectional view of a main part of a modified example of the recess of the probe needle according to the fourth embodiment. Fig. 9B yes Fig.9A GG cross-sectional view. Fig.10 It is a figure which shows the manufacturing method of the probe using a punch according to the fourth embodiment. Fig.11A It is a plan view of the main part of the protrusion of the probe of the fifth embodiment. Fig. 11B yes Fig.11A MM cross-sectional view. DETAILED DESCRIPTION

[0011] Implementation method 1. Hereinafter, a cantilever probe for a probe card and a probe card according to a first embodiment will be described with reference to the drawings. Figure 1 1 is a perspective view of a cantilever probe 20 for a probe card (hereinafter simply referred to as a probe 20 ) according to Embodiment 1. This is a perspective view before mounting on a wiring board of a probe card (not shown). In this manual, Figure 1 The above of the paper is referred to as "upper" and the below of the paper is referred to as "lower". The direction in which the probe 20 is buckled (elastically deformed) during overdrive is referred to as the buckling direction X, and the thickness direction of the probe 20, which is a direction perpendicular to the buckling direction, i.e., the direction in which the metal film is stacked during manufacture of the probe 20, is referred to as the plate thickness direction Y. In addition, the length direction of the terminal portion 21T of the probe 20 is referred to as the length direction Z.

[0012] The probe 20 is a component used in a probe card (not shown). The probe card is a device used to inspect the electrical characteristics of an electronic circuit formed on a semiconductor wafer. The characteristics inspection of the electronic circuit is performed as follows: the probe card is brought close to the semiconductor wafer, the tip of the probe 20 is brought into contact with an electrode on the electronic circuit, and the test device is connected to the test connection electrode of the wiring substrate of the probe card via the probe 20.

[0013] The probe 20 is a cantilever probe that is arranged such that the beam portion 21B is substantially horizontal with respect to the inspection object (electronic circuit formed on a semiconductor wafer).

[0014] The probe 20 has a thin plate-shaped main body 21 and a needle tip 22 protruding upward from the upper end of the main body. The main body 21 includes a terminal 21T disposed at Figure 1 A wiring pad of a wiring substrate (not shown) below the paper is connected; a base portion 21D rising upward from the terminal portion 21T; and an elastic deformation portion 21U located between the base portion 21D.

[0015] The elastic deformation part 21U has a long hole 21UH extending in the longitudinal direction Z and penetrating in the plate thickness direction Y. The elastic deformation part 21U is divided into two beam parts 21B by the long hole 21UH. Figure 1 Although an example including two beam portions 21B is shown in the figure, the number of beam portions 21B may be one, or three or more.

[0016] When the probe 20 is overdriven, Figure 1 The inspection object is easily buckled and deformed in the buckling direction X by the reaction force from the inspection object due to the compressive force in the vertical direction.

[0017] Figure 2A yes Figure 1 2 is a top view of a portion surrounded by a dotted line. This is a view of the vicinity of the terminal portion 21T side of the base portion 21D as viewed along the plate thickness direction Y of the probe 20. Figure 2B yes Figure 2A AA section view.

[0018] The probe 20 is composed of two metals with electrical conductivity and different resistivity. One of them is the inner metal (first metal) constituting the low resistance portion L, and the low resistance portion L is made of metals with low resistivity such as copper, gold, silver (Cu, Au, Ag). The low resistance portion L has the effect of making the electrical conductivity higher and improving the current resistance performance. The other is the outer metal (second metal) constituting the high resistance portion H, and the high resistance portion H is made of metals with resistivity higher than the low resistance portion L such as palladium cobalt (PdCo) alloy, and the high resistance portion H has low electrical conductivity but high mechanical strength and elasticity. The high resistance portion H works to maintain the mechanical strength of the probe 20.

[0019] like Figure 1 , Figure 2A , Figure 2B As shown, near the terminal portion 21T of the two surfaces 21DS in the plate thickness direction Y of the base portion 21D of the probe 20, a plurality of quadrangular prism-shaped recesses 21R are formed in a row along the longitudinal direction Z. Figure 2AAs shown, a tin alloy layer 21Sn is formed to completely cover the terminal portion 21T side from a line segment B connecting the upper end of the recess 21R and from a line segment C connecting the lower end. The probe 20 is fixed to the pad of the wiring board by melting the tin alloy layer 21Sn.

[0020] Figure 3 1 and 2. This is a cross-sectional view of the vicinity of the terminal portion 21T of the probe 20 soldered to the pad Ln of the wiring board K cut perpendicularly with respect 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 pad Ln of the wiring substrate K and the tin alloy layer 21Sn is heated, the melted tin alloy adheres to the inner wall surface of the recess 21R and solidifies into a rounded shape together with the tin alloy layer 21Sn formed on the rest of the end surface including the terminal portion 21T.

[0021] The recess 21R is formed in the high resistance portion H. Here, for the probe 20 provided with the quadrangular prism-shaped recess 21R, the stress after soldering was calculated using the finite element method (FEM), and it was found that the stress of the solder solidified after melting is concentrated on Figure 2B Each vertex 10B of the recess 21R and an edge line 10 formed by two adjacent surfaces constituting the recess 21R are shown.

[0022] Thus, by arranging the quadrangular prism-shaped depressions 21R as stress dispersion portions uniformly along the longitudinal direction Z on the base portion 21D of the probe 20 , the stress acting on the fixed portion due to welding can be uniformly dispersed to the vertices 10B and ridges 10 of the depressions 21R.

[0023] Figure 4 The sacrificial layer G is configured to produce Figure 1 The stacking direction R indicates the stacking direction of the metal layers during manufacturing.

[0024] The probe 20 is manufactured using the so-called MEMS (Micro Electro Mechanical Systems) technology. MEMS technology is a technology for manufacturing fine three-dimensional structures using photolithography and sacrificial layer etching technology. Photolithography is a processing technology for fine patterns using photoresist used in semiconductor manufacturing processes, etc. In addition, the sacrificial layer etching technology is a technology in which a lower layer called a sacrificial layer G is formed, and after a layer constituting a structure is formed on it, only the sacrificial layer G is removed by etching to manufacture a three-dimensional structure.

[0025] In the formation process of the high resistance portion H and the low resistance portion L, a known plating technique can be used. For example, the substrate as the cathode and the metal sheet as the anode are immersed in an electrolyte, and a voltage is applied between the two electrodes, so that the metal ions in the electrolyte can be attached to the surface of the substrate. Such a process is called electroplating, which is a wet process in which the substrate is immersed in an electrolyte. Therefore, a drying process is performed after the plating process. After the drying process, the needle tip 22 is ground by a grinding process.

[0026] Specifically, first, a portion other than the portion corresponding to the recess 21R is formed. Figure 2B Next, a high resistance portion H is formed on the upper side of the lower recess 21R and on the lower side of the low resistance portion L. Next, a low resistance portion L is formed. Next, as shown in FIG. Figure 2B As shown in FIG. 1 , a high resistance portion H is formed above the low resistance portion L and below the lower surface of the upper recess 21R. Next, a high resistance portion H is formed above the low resistance portion L. Figure 2B The high resistance portion H other than the recess 21R on the upper side.

[0027] Next, the tin alloy layer 21Sn is formed by dipping the terminal portion 21T into the molten tin alloy in the above-mentioned predetermined range. A plurality of recesses 21R are formed near the terminal portion 21T along the longitudinal direction Z of the base portion 21D, so that the tin alloy layer 21Sn can be prevented from rising over the recesses 21R. In addition, in the formation of the tin alloy layer 21Sn, a mask may be applied to the periphery other than the portion where the tin alloy layer 21Sn is formed, and the tin alloy layer 21Sn may be plated.

[0028] Then, the terminal portion 21T of the probe 20 formed with the tin alloy layer 21Sn is pressed against the pad Ln of the wiring board K and heated to melt the tin alloy layer 21Sn, thereby soldering the probe 20 to the pad Ln.

[0029] like Figure 3 As shown in FIG. 1 , the molten tin alloy layer 21Sn (solder) adheres to and is fixed to the inner wall surface of the recess 21R. In addition, the molten tin alloy layer 21Sn (solder) does not rise above the base portion 21D beyond the upper surface of the recess 21R. Figure 3 As shown, the cross-sectional shape of the tin alloy layer 21Sn after the bonding sandwiches the terminal portion 21T in the up-down direction, but the recess 21R does not penetrate along the stacking direction R of the probe 20, so that when the solder solidifies, it will not cause excessive stress to be applied to the terminal portion 21 due to shrinkage. In addition, the stress can be dispersed to the plurality of recesses 21R, so that stable bonding of the probe 20 can be achieved.

[0030] In addition, in this embodiment, an example in which the high resistance portion H and the low resistance portion L are made of two kinds of metals is shown, but they may also be made of a single kind of metal.

[0031] According to the cantilever probe for a probe card and the probe card of the first embodiment, the stress generated inside the probe 20 when soldered to the pad Ln of the wiring substrate K can be uniformly dispersed to each vertex 10B and each ridge 10 of the recess 21R, thereby providing a cantilever probe for a probe card with high mechanical strength.

[0032] Furthermore, since the solder can be prevented from rising during bonding by the recess 21R, it is possible to provide a cantilever probe for a probe card and a probe card in which bonding quality of the probe 20 is not varied.

[0033] Furthermore, the excess solder can be stored in the recess 21R, and therefore, the fillet shape can be prevented from excessively expanding in the lateral direction.

[0034] In addition, the portion 21Sin of the solder formed in the recess 21R after fixing is cantilevered relative to the end face joint portion 21TS formed between the pad Ln and the terminal portion 21T as a fixing layer of the solder by the solder 21Sout covering the side of the base portion 21D, and is therefore flexible and durable and will not peel off.

[0035] Implementation method 2. Hereinafter, the cantilever probe for a probe card and the probe card according to the second embodiment will be described centering on the parts different from the first embodiment. Figure 5 1 is a perspective view of a cantilever probe 20 for a probe card (hereinafter referred to as simply a probe 20 ) according to Embodiment 2. This is a perspective view before mounting on a wiring board K of a probe card (not shown). Figure 6 yes Figure 5 2 is a top view of a portion surrounded by a dotted line. This is a view of the vicinity of the terminal portion 21T side of the base portion 21D as viewed along the plate thickness direction Y of the probe 20. Figure 7 1 and 2. This is a cross-sectional view of the vicinity of the terminal portion 21T of the probe 20 soldered to the pad Ln of the wiring board K cut perpendicularly with respect to the longitudinal direction Z at the portion of the recess 21R.

[0036] In the first embodiment, an example is shown in which a plurality of quadrangular prism-shaped recesses 21R are formed in a row along the longitudinal direction Z near the terminal portion 21T of the two surfaces 21DS in the plate thickness direction Y of the base portion 21D of the probe 20, but the present embodiment is different in that two rows are formed along the longitudinal direction Z. In addition, in the second embodiment, the tin alloy layer 21Sn is formed in a range from Figure 6 The area between the line segment D and the line segment E toward the terminal portion 21T side. The line segment D is a line segment connecting the upper ends of the row of recesses 21R on the needle tip portion 22 side, and the line segment E is a line segment connecting the lower ends on the terminal portion 21T side of the same row.

[0037] Thus, when a plurality of rows of recesses 21R are provided along the longitudinal direction Z, when the tin alloy layer 21Sn is formed to cover at least a portion of the interior of the uppermost recess 21R (needle tip 22 side), the same effects as those of the first embodiment are achieved.

[0038] Implementation method three. Hereinafter, the cantilever probe for a probe card and the probe card according to the third embodiment will be described centering on the parts different from the first embodiment. Fig. 8A 1 is a plan view of a main part of a modified example of the recess 21R of the probe 20 . 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 . Figure 8B yes Fig. 8A FF cross-sectional view.

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

[0040] This structure also achieves the same effect as the first embodiment. In this way, the depth of the recess 21R is preferably changed according to the required mechanical strength. Alternatively, the recess may only penetrate the high resistance portion H. In this case, the number of manufacturing steps of the probe 20 can be reduced.

[0041] Implementation method four. Hereinafter, the cantilever probe for a probe card and the probe card according to the fourth embodiment will be described centering on the parts different from the first embodiment. Fig.9A 1 is a plan view of a main part of a modified example of the recess 21R of the probe 20 . 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. 9B yes Fig.9A GG cross-sectional view.

[0042] So far, the example of providing the quadrangular prism-shaped recess 21R near the terminal portion 21T side of the base portion 21D has been described, but the recess 21R may also be a dimple-shaped, that is, a hemispherical recess. However, this shape cannot be formed by laminating metal layers, and therefore is formed by stamping.

[0043] Fig.10 It is a figure which shows the manufacturing method of the probe 20 using a punch. The probe 20 having the high resistance portion H stacked on the high resistance portion H is pressed from both sides by the first mold 51 and the second mold 52 having hemispherical protrusions corresponding to the respective recesses 21R, thereby forming the hemispherical recesses 21R on the surface.

[0044] In this case, the production time can be shortened compared to forming the metal layer by electroforming. In addition, the recess 21R may be in the shape of a polygonal column, a polygonal truncated pyramid, a cylindrical shape, or a truncated pyramid. The recess 21R in these shapes can also be manufactured by stamping. After the recess 21R is formed, the recess 21R is formed within the above-mentioned range (within Fig.10 In the figure, a tin alloy layer 21Sn is formed from the line segment J toward the terminal portion 21T side.

[0045] According to the cantilever probe for a probe card and the probe card of the fourth embodiment, the same effects as those of the first embodiment are achieved.

[0046] Implementation method five. Hereinafter, the cantilever probe for a probe card and the probe card according to the fifth embodiment will be described centering on the parts different from the first embodiment. Fig.11A 1 is a plan view of a main part of a protrusion 21P as a modified example of the stress dispersion portion of the probe 20 . 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. 11B yes Fig.11A MM cross-sectional view. So far, the recess 21R as the stress dispersion portion has been described. Fig.11A , Fig. 11B As shown, the stress dispersion portion may also be the protrusion 21P.

[0047] According to the cantilever probe for a probe card and the probe card of the fifth embodiment, the same effects as those of the first embodiment are achieved.

[0048] The present application describes various exemplary embodiments and examples, but various features, methods, and functions described in one or more embodiments are not limited to application to specific embodiments and can be applied to the embodiments alone or in various combinations. Therefore, numerous modifications not shown are contemplated within the technical scope disclosed in this application, including, for example, modifications, additions, or omissions of at least one component, and also including extraction of at least one component and combination with components of other embodiments. Explanation of symbols

[0049] 20 cantilever probe for probe card; 10 edge 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 long hole; 22 needle tip; 21P protrusion; 51 first mold; 52 second mold; G sacrificial layer; H high resistance portion; L low resistance portion; Ln pad; R stacking direction; X bending direction; Y plate thickness direction; Z length direction; K wiring substrate.

Claims

1. A cantilever probe for a probe card, characterized in that: include: A base portion rising upward from a terminal portion connected to a wiring substrate; a needle tip portion; and a beam portion located between the base portion and the needle tip portion, The base portion includes a plurality of three-dimensional stress dispersion portions along a length direction of the terminal portion, and the stress dispersion portions are recesses or protrusions.

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

3. The cantilever probe for a probe card according to claim 1, characterized in that: The stress dispersion portions are arranged in a plurality of rows along a length direction of the base portion.

4. The cantilever probe for a probe card according to claim 1, characterized in that: The stress dispersion portion may be in any of a polygonal column shape, a polygonal truncated cone shape, a cylindrical shape, a hemispherical shape, and a truncated cone shape.

5. The cantilever probe for a probe card according to any one of claims 1 to 4, characterized in that: The beam portion includes: a low resistance portion formed of a low resistance metal layer; and A high resistance portion having a higher resistance than that of the low resistance portion and having elasticity is disposed outside the low resistance portion. The stress dispersion portion is formed in the high resistance portion.

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

7. A probe card, comprising: A cantilever probe for a probe card, the cantilever probe for a probe card comprising a base portion rising upward from a terminal portion connected to a wiring substrate, a needle tip portion, and a beam portion located between the base portion and the needle tip portion; and The wiring substrate and the probe card are characterized in that: The base portion includes a plurality of three-dimensional stress dispersion portions along the length direction of the terminal portion, wherein the stress dispersion portions are recessed. In the solder layer fixing the probe to the pad of the base plate, a portion formed in the stress dispersion portion is fixed relative to the solder end surface joint formed between the pad and the terminal portion of the probe by the solder layer cantilever covering the side surface of the base portion.

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