Probe for probe card

Abstract

A probe (20) for a probe card, which is in contact with an electrode pad of a semiconductor device, supplies power, inputs and outputs signals, and grounds to perform an operation test of each semiconductor device formed on a wafer (W), is provided with a plurality of stress dispersion chambers (201K) having a three-dimensional shape, the stress dispersion chambers (201K) being embedded inside the probe (20). And a ridge line (10) and an apex (10B) formed by the inner wall surface.

Description

Technical Field

[0001] The present application relates to a probe for a 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. The probe needs to be made finer to match the miniaturization of semiconductor devices. However, when the probe is made finer, there is a problem that the mechanical strength of the probe is weakened.

[0004] Therefore, in order to ensure good electrical and mechanical contact with the electrode pad of the semiconductor device, for example, Patent Document 1 proposes a structure using a multilayer metal sheet in a probe. Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2018-501490 Summary of the invention Technical problem to be solved by the invention

[0006] Patent document 1 discloses a probe having at least one multilayer structure and an outer coating, wherein the multilayer structure includes a core and a first inner coating overlapping each other, and the outer coating completely covers the multilayer structure and is made of a material having a higher hardness than the core. As shown in Patent Document 1, in order to achieve good electrical and mechanical contact, a structure in which multiple layers of different materials are stacked is preferred. However, this structure has limitations in satisfying the requirement of reducing the cross-sectional thickness of the probe, and further breakthroughs are needed.

[0007] In the inspection process using the probe card, in order to ensure contact with the electrode pads of the semiconductor device, after the probes contact the electrode pads, the probe card is brought closer to the semiconductor wafer (overdrive) to press the probes against the electrode pads of the semiconductor device. Therefore, the probe needs to have a strength that will not be mechanically damaged even if a contact pressure exceeding a specified value is applied. In order to prevent the probe from being damaged, it is necessary not to generate local stress concentration on the probe. In addition, in order to avoid this stress concentration, the probe is required to have a smooth surface and no damage as much as possible.

[0008] However, there are limitations in smoothing the metal surface, and there is a problem that the thinner the cross-section of the probe is, the easier it is to deform in response to external forces (the mechanical strength decreases).

[0009] The present application discloses a technology for solving the above-mentioned technical problems, and its object is to provide a probe for a probe card which can contact an electrode pad of a semiconductor device with an appropriate needle pressure even if it becomes fine, and has a strength that will not be broken even if a contact pressure exceeding a specified value is applied.

[0010] That is, the probe card probe of the present application is a probe card probe with high mechanical strength that is capable of withstanding large stress by having a structure in which the locations where stress concentration occurs are intentionally dispersed, rather than not causing stress concentration. Technical solutions adopted to solve technical problems

[0011] The probe card probe disclosed in the present application includes a plurality of three-dimensional stress dispersion chambers. The stress dispersion chamber is embedded in the probe and has a ridgeline and a vertex formed by an inner wall surface. Effects of the Invention

[0012] According to the probe card probe disclosed in the present application, it is possible to provide a probe card probe in which the locations where stress concentration occurs are dispersed and the mechanical strength is high even if the plate thickness is set to be thin. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram schematically showing a state in which an electronic circuit is inspected using the probe card of the first embodiment. Figure 2 This is a perspective view of the probe according to the first embodiment. Figure 3 It is a plan view showing the shapes of three metal layers constituting the probe pin of the first embodiment. Figure 4 yes Figure 2 The AA cross-sectional view is a cross-sectional view obtained by cutting perpendicularly to the longitudinal direction Z of the probe. Figure 5 This is a perspective view of a probe according to the second embodiment. Figure 6 It is a plan view showing the shapes of three metal layers constituting the probe of the second embodiment. Figure 7 yes Figure 5 BB cross-sectional view. Figure 8 This is a cross-sectional view obtained by cutting the probe according to the third embodiment perpendicularly to the longitudinal direction Z. Fig. 9 This is a perspective view of a probe according to a fourth embodiment. Fig.10 It is a plan view showing the shapes of three metal layers constituting the probe pin of the fourth embodiment. Fig.11 This is a perspective view of a probe according to the fifth embodiment. Fig.12 A is Fig.11 CC cross-sectional view. Fig.12 B is a cross-sectional view showing a modified example of the probe of the fifth embodiment. DETAILED DESCRIPTION

[0014] Implementation method 1. Hereinafter, the probe card probe according to the first embodiment will be described with reference to the drawings. Figure 1 This is a diagram schematically showing an inspection state of an electronic circuit using the probe card 100 . In this manual, Figure 1 In the description, the upper side of the paper is referred to as "upper" and the lower side of the paper is referred to as "lower". That is, when viewed from the probe card 100, the side to be inspected is referred to as "lower". Figure 1 The left-right direction of the paper is defined as the buckling direction X, and the direction from the front to the depth of the paper and the reverse direction are defined as the direction Y perpendicular to the buckling direction X. Figure 1 The vertical direction of the paper (the vertical direction) is set as the length direction Z.

[0015] The probe card 100 is a device for inspecting the electrical characteristics of an electronic circuit formed on a semiconductor wafer W. The probe card 100 includes a plurality of probes 20 that are respectively in contact with electrodes C on the electronic circuit. The characteristics inspection of the electronic circuit is performed as follows: the probe card 100 is brought close to the semiconductor wafer W, the tips of the probes 20 are brought into contact with the electrodes C on the electronic circuit, and the electrodes C are connected to a test device (not shown) via the test connection electrodes TC of the wiring substrate 14 of the probe card 100 and the probes 20.

[0016] The probe card 100 includes a hollow frame 1, an upper guide 11 mounted on the upper end of the frame 1, a lower guide 12 mounted on the lower end of the frame 1, a fixing plate 13 fixing the upper guide 11, and a wiring substrate 14. An intermediate guide may be provided between the upper guide 11 and the lower guide 12.

[0017] The upper guide 11 has a plurality of guide holes 11H extending in the vertical direction. The lower guide 12 provided below the upper guide 11 has a plurality of guide holes 12H extending in the vertical direction. Above the plurality of guide holes 11H provided in the upper guide 11 is an opening 13H provided in the fixing plate 13. A wiring substrate 14 is provided on the upper surface of the fixing plate 13. The wiring substrate 14 includes a plurality of probe connection pads 14P on its lower surface that contact the terminal portion 20t at the upper end of the probe 20.

[0018] In addition, the plurality of probes 20 are inserted and guided so as to pass through the guide holes 12H and the guide holes 11H, respectively. The probes 20 are vertical probes arranged vertically with respect to the inspection object (electronic circuit formed on the semiconductor wafer W).

[0019] Figure 1 The left-right direction is the bending direction X of the probe 20, that is, the direction in which the probe 20 is elastically deformed when the probe card 100 is overdriven. The probe 20 is in the shape of an elongated quadrangular prism. The probe 20 extends in a straight line in the up-down direction. The lower end (one end) of the probe 20 includes a contact portion 20c. In addition, a terminal portion 20t is formed at the upper end (the other end).

[0020] When overdriven, the probe 20 is subjected to a compressive force in the longitudinal direction Z and is easily buckled and deformed in the buckling direction X by a reaction force from the inspection object. The contact portion 20 c retreats toward the terminal portion 20 t , and stress is generated inside the probe 20 .

[0021] Figure 2 is a perspective view of the probe 20 . Figure 3 1 is a plan view showing the shapes of three metal layers constituting the probe 20 . The probe 20 is made of a conductive metal. The first metal layer 20L1 to the third metal layer 20L3 of the probe 20 are thin layers of the same metal. The first metal layer 20L1 and the third metal layer 20L3 are formed in a flat plate shape. Moreover, in the second metal layer 20L2 sandwiched between the first metal layer 20L1 and the third metal layer 20L3, a plurality of hexagonal prism-shaped holes 20H are spaced apart in the longitudinal direction Z of the probe 20 and are arranged in a penetrating direction R of the stacking direction of the metal layers of the probe 20. The first metal layer 20L1, the second metal layer 20L2 and the third metal layer 20L3 are stacked in sequence and welded to be integrated.

[0022] exist Figure 2 In the figure, the buckling direction X is the same as the stacking direction R of the three metal layers, but the buckling direction may be a direction Y orthogonal to the stacking direction R of each metal layer.

[0023] Figure 4yes Figure 2 The AA cross-sectional view is a cross-sectional view obtained by cutting perpendicularly to the longitudinal direction Z of the probe 20. Figure 4 The left-right direction of the paper is the buckling direction X. In the cross section perpendicular to the length direction Z of the probe 20, at the portion where the hole 20H is arranged in the second metal layer 20L2, as shown in FIG. Figure 4 As shown, the hole 20H becomes a hollow portion 20K1 (stress dispersion chamber) which is blocked by its inner wall, the first metal layer 20L1 and the third metal layer 20L3 . In this way, the hollow portion 20K1 is formed inside the probe 20 .

[0024] Here, when the probe A having no cavity 20K1 is compared with the probe 20 having the cavity 20K1 , the probe 20 having the cavity K1 has a smaller needle pressure in relation to the overdrive amount.

[0025] Furthermore, the effects that can be obtained by the hollow portion 20K1 are analyzed. The maximum stress of the probe A without the hollow portion 20K1 and the probe 20 with the hexagonal hollow portion 20K1 are calculated based on the finite element method (FEM). It is found that when a force is applied from the outside, the stress is concentrated at Figure 2 Each vertex 10B of the cavity 20K1 and an edge line 10 formed by two adjacent surfaces constituting the cavity 20K1 are shown.

[0026] Therefore, by burying hexagonal prism-shaped cavities 20K1 as stress dispersion chambers in a manner arranged at predetermined intervals in the longitudinal direction Z of the probe 20 , stress can be evenly dispersed in each vertex 10B and each ridge line 10 .

[0027] The first metal layer 20L1 to the third metal layer 20L3 of the probe 20 are manufactured using the so-called MEMS (Micro ElectroMechanical Systems) technology (probe intermediate formation process). MEMS technology is a technology that uses photolithography technology and sacrificial layer etching technology to manufacture fine three-dimensional structures. Photolithography technology is a processing technology for fine patterns using photoresist that is used in semiconductor manufacturing processes, etc. In addition, the sacrificial layer etching technology is a technology that forms a lower layer called a sacrificial layer, forms a layer constituting a structure on it, and then removes only the sacrificial layer by etching to manufacture a three-dimensional structure.

[0028] Well-known plating techniques can be used in the formation process of the first metal layer 20L1 to the third metal layer 20L3. For example, a substrate as a cathode and a metal sheet as an anode are immersed in an electrolyte, and a voltage is applied between the two electrodes, so that 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 a substrate is immersed in an electrolyte. Therefore, after the plating process, a drying process is performed to obtain each of the first metal layer 20L1 to the third metal layer 20L3. After the drying process, the first metal layer 20L1 to the third metal layer 20L3 are stacked and welded. The portion serving as the lower front end is ground by a grinding process (grinding process), and a contact portion 20c is formed.

[0029] According to the probe card probe of the first embodiment, the stress generated inside the probe 20 during inspection can be dispersed to each vertex 10B and each ridge line 10 of the cavity 20K1, so that both maintenance of mechanical strength and reduction of the needle pressure can be achieved.

[0030] Implementation method 2. Hereinafter, the probe card probe of the second embodiment will be described focusing on the parts different from the first embodiment. Figure 5 is a perspective view of the probe 20 . Figure 6 1 is a plan view showing the shapes of three metal layers constituting the probe 20 . Figure 7 yes Figure 5 BB cross-sectional view. In the first embodiment, the probe 20 is described in which a plurality of independent hexagonal prism-shaped hollow portions 20K1 are arranged in the length direction Z and buried inside a metal column composed of three metal layers. In the second embodiment, the plurality of hollow portions 20K1 of the probe 20 are connected to each other through a thin hollow portion 20K2. Furthermore, the hollow portion 20K2 is connected to the outside of the probe 20 at multiple locations.

[0031] The cavity 20K1 and the cavity 20K2 are initially formed as a sacrificial layer during the process of manufacturing the probe 20, and are formed by being removed by etching. That is, in the first embodiment, in order to form the cavity 20K1, after the first metal layer 20L1 to the third metal layer 20L3 are manufactured respectively, they need to be welded. In the second embodiment, all the holes 20H of the second metal layer 20L2 are connected by the groove 20M1. Moreover, there is the following advantage: by forming at least two grooves 20M2 that are connected to several holes 20H and open to the outside of the probe 20, the probe 20 can be manufactured through a series of processes.

[0032] The manufacturing process of the probe 20 is roughly as follows. First, the first metal layer 20L1 is formed. Then, the second metal layer 20L2 is formed except for the portion that becomes the hole 20H and the grooves 20M1 and 20M2. Then, a sacrificial layer is formed in the hole 20H, the groove 20M1, and the groove 20M2. Then, the third metal layer 20L3 is formed. Finally, the sacrificial layer is melted to form a plurality of hollow portions 20K1 and hollow portions 20K2 inside the probe 20.

[0033] According to the probe card probe of the second embodiment, all the steps can be completed as a series of steps implemented by MEMS. Therefore, in addition to the effects of the first embodiment, a probe 20 with high mechanical strength can be provided.

[0034] Implementation method three. Hereinafter, the probe card probe of the third embodiment will be described focusing on the parts different from the first embodiment. Figure 8 This is a cross-sectional view obtained by cutting the probe 20 perpendicularly with respect to the longitudinal direction Z. In this embodiment, an example in which the cavity 20K1 is sealed with a material different from the probe 20 body is described. Figure 4 The portion of the cavity 20K1 described in the first embodiment is shown. As the material to be contained, for example, metal such as Au or resin is listed. In the case of containing Au, after forming the second metal layer 20L2 described in the second embodiment, an Au layer is formed in the cavity 20K1, and then a third metal layer 20L3 is formed and sealed. The same is true for the case of resin.

[0035] According to the probe card probe of the third embodiment, all the steps can be completed as a series of steps implemented by MEMS as in the second embodiment. Therefore, in addition to the effects of the first embodiment, a probe 20 having high mechanical strength can be provided.

[0036] When Au or the like is used as the metal accommodated in the hole 20H, the conductivity of the probe is improved, and the same effects as those of the first embodiment are achieved. When a resin is accommodated, the flexibility of the probe 20 when buckled and deformed can be increased.

[0037] Implementation method four. Hereinafter, the probe card probe of the fourth embodiment will be described focusing on the parts different from the first embodiment. Fig. 9 is a perspective view of the probe 20 . Fig.10 1 is a plan view showing the shapes of three metal layers constituting the probe 20 .

[0038] The probe 20 is formed of three metal layers, which is the same as that of the first embodiment. The probe 20 of the present embodiment is different from the probe 20 of the first embodiment in the structure of the second metal layer 20L2. Notches 20CT recessed toward the inside of the probe 20 are alternately provided in the longitudinal direction Z of the probe 20 on both sides of the second metal layer 20L2 in the direction Y perpendicular to the buckling direction X.

[0039] The manufacturing process of the probe 20 is roughly as follows. First, the first metal layer 20L1 is formed. Then, the second metal layer 20L2 is formed on the first metal layer 20L1 except for the portion that serves as the notch portion 20CT. Then, a sacrificial layer is formed on the notch portion 20CT. Then, a third metal layer 20L3 is formed on the second metal layer 20L2. Finally, the sacrificial layer is melted to form a plurality of hollow portions 20K3 inside the probe 20. The hollow portions 20K3 are open to the outside of the probe 20.

[0040] As in the third embodiment, a resin or a metal softer than the probe 20 body and having a lower resistance may be placed in the cavity 20K3 to seal the cavity 20K3. In this case, the same effects as those of the third embodiment are achieved.

[0041] Implementation method five. Hereinafter, the probe card probe of the fifth embodiment will be described focusing on the parts different from the first embodiment. Fig.11 is a perspective view of the probe 20 . Fig.12 A is Fig.11 CC cross-sectional view. Fig.12 B is a cross-sectional view showing a modified example of the probe 20 . like Fig.11 As shown, the probe 20 is composed of two metals with different resistivities. One of them is a metal composed of a metal with a lower resistivity such as copper, gold, silver (Cu, Au, Ag), which constitutes the metal on the inside of the low resistance portion L. The low resistance portion L has a higher conductivity, which plays a role in improving the current resistance performance. The other is a metal with a resistivity higher than the resistivity of the low resistance portion L, such as a palladium cobalt (PdCo) alloy, which has a lower conductivity, a higher mechanical strength and elasticity, which constitutes the metal on the outside of the high resistance portion H. The high resistance portion H plays a role in maintaining the mechanical strength of the probe 20.

[0042] like Fig.12 A. Fig.12As shown in FIG. 2B , the high-resistance portion H of the probe 20 surrounds the low-resistance portion L. Furthermore, if only the high-resistance portion H is focused on, a plurality of quadrangular-prism-shaped depressions 20R are formed on the inner walls on both sides of the high-resistance portion H in the buckling direction X. The depressions 20R (stress dispersion chambers) are formed at equal intervals along the longitudinal direction Z of the probe 20.

[0043] You can also Fig.12 As shown in FIG. 2B , a plurality of rows of small depressions 20R are arranged along the length direction Z of the probe 20. Moreover, the depression 20R is a low resistance portion L. Therefore, if only the low resistance portion L is focused on, the low resistance portion L includes a plurality of protrusions LT protruding from both sides of the buckling direction X in the buckling direction X. As described above, the stress acting on the inside of the probe 20 is concentrated on each vertex 10B and each ridge 10 formed in the probe 20. Therefore, by evenly arranging a plurality of depressions 20R inside the high resistance portion H having high mechanical strength and springiness, it is possible to achieve an even dispersion of the stress acting on the inside when the probe 20 is buckled and deformed.

[0044] 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)

[0045] 100 probe card; 1 frame; 10 edge line; 10B vertex; 11 upper guide; 11H guide hole; 12 lower guide; 12H guide hole; 13 fixing plate; 13H opening; 14 wiring substrate; 14P probe connection pad; 20 probe; 20c contact portion; 20H hole; 20K1, 20K2, 20K3 cavity portion; 20M1, 20M2 groove; 20R recess; 20t terminal portion; C electrode; H high resistance portion; 20CT notch portion; L low resistance portion; H high resistance portion; 20L1 first metal layer; 20L2 second metal layer; 20L3 third metal layer; LT protrusion; R stacking direction; TC test connection electrode; W semiconductor wafer; X buckling direction; Y direction orthogonal to the buckling direction; Z length direction.

Claims

1. A probe for a probe card, characterized in that: The probe includes a plurality of three-dimensional stress dispersion chambers, which are embedded in the interior of the probe and have ridges and apexes formed by inner wall surfaces.

2. The probe card probe according to claim 1, wherein: The probe includes a plurality of stress dispersion chambers arranged in a plurality of rows and spaced apart from each other in a longitudinal direction of the probe.

3. The probe for a probe card according to claim 1, wherein: The probe includes: a low resistance portion, the low resistance portion being composed of a low resistance metal layer; and a high resistance portion, the high resistance portion being located outside the low resistance portion, having a higher resistance than the low resistance portion and having elasticity, The stress dispersion chamber is formed in the high resistance portion.

4. The probe for a probe card according to claim 1, wherein: The stress dispersion chamber opens toward the outer side surface of the probe.

5. The probe for a probe card according to claim 1, wherein: The stress dispersion chamber contains a metal having a lower electrical resistance than surrounding metals.

6. The probe for a probe card according to claim 1, wherein: Resin is accommodated in the stress dispersion chamber.

7. The probe for a probe card according to claim 3, wherein: The stress dispersion chamber contains the same metal as that of the low resistance portion.

8. The probe for a probe card according to claim 1, wherein: The stress dispersion chamber is a cavity.

9. The probe for a probe card according to claim 8, wherein: All of the stress dispersion chambers are in communication with the outside of the probe.

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