Probe for probe card

Abstract

A probe (20) for a probe card includes, on at least one side surface (20S) of two side surfaces (20S) perpendicular to each of two surfaces perpendicular to a buckling direction (X) of the probe (20): a plurality of deformation regions (8) arranged at intervals in a longitudinal direction (Z) of the probe (20) as a row and including two rows of recesses with respect to the side surface (20S); and a zigzag skeleton region (9) located between the plurality of deformation regions (8) in two rows, the skeleton region (9) being longer than the length of the probe (20) in the longitudinal direction (Z).

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] The probe shown in patent document 1 discloses a contact probe having at least one multilayer structure and an outer coating, wherein the multilayer structure includes a core and a first inner coating overlapping, and the outer coating completely covers the multilayer structure, is made of a material with a higher hardness than the core, and completely covers the multilayer structure. 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 against an external force, and the lower the mechanical strength.

[0009] The present application discloses a technology for solving the above-mentioned technical problems, and its object is to provide a probe 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 purpose of the probe card probe of the present application is to provide a probe card probe that is not free of stress concentration but can withstand large stress (with high mechanical strength) by having a structure in which the locations where stress concentration occurs are intentionally dispersed. Technical solutions adopted to solve technical problems

[0011] The probe card probe disclosed in the present application, The reference surface of the probe on at least one of the two side surfaces perpendicular to the two surfaces perpendicular to the buckling direction of the probe comprises: a plurality of deformation regions, wherein the plurality of deformation regions are depressions with respect to the side surface, which are arranged in a row and spaced apart in a longitudinal direction of the probe and include two rows of depressions spaced apart; and a sawtooth-shaped skeleton region, the skeleton region being located between the plurality of deformation regions in the two columns, The length of the framework region is longer than the length of the probe in the longitudinal direction. 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 yes Figure 2 It is an AA cross-sectional view of the probe, and is a cross-sectional view perpendicular to the length direction of the probe. Figure 4 This is a diagram showing the positional relationship between deformation regions arranged in two rows according to the first embodiment. Figure 5 It is a cross-sectional view showing a modified example of the probe of the first embodiment. Figure 6 This is a cross-sectional view perpendicular to the longitudinal direction of the probe according to the second embodiment. Figure 7 This is a cross-sectional view perpendicular to the longitudinal direction of the probe according to the third embodiment. Figure 8 It is a cross-sectional view showing a modified example of the probe of the third embodiment. Fig. 9 A is a diagram showing changes in the deformation region in the fourth embodiment. Fig. 9 B is a diagram showing changes in the deformation region in the fourth embodiment. Fig. 9 C is a diagram showing changes in the deformation region in the fourth embodiment. Fig.10 A is a diagram showing changes in the deformation region in the fifth embodiment. Fig.10 B is a diagram showing changes in the deformation region in the fifth embodiment. Fig.10 C is a diagram showing changes in the deformation region in the fifth embodiment. Fig.11 It is a diagram showing changes in the deformation region in 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 the buckling direction X, and the direction from the front to the depth of the paper and the reverse direction are set as the direction Y perpendicular to the buckling direction X. In addition, the length direction ( 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 formed on the electronic circuit of the semiconductor wafer W. The characteristics inspection of the electronic circuit is performed as follows: the probe card 100 is brought close to the semiconductor wafer W, the tip of the probe 20 is brought into contact with the electrode C on the electronic circuit, and a test device (not shown) is connected to the test connection electrode TC of the wiring substrate 14 of the probe card 100 via the probe 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 member 11 has a plurality of guide holes 11H extending in the vertical direction, and the lower guide member 12 provided below the upper guide member 11 also has a plurality of guide holes 12H extending in the vertical direction. Above the plurality of guide holes 11H provided in the upper guide member 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 2 is a perspective view of the probe 20 . Figure 2 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 an elongated shape. The central portion is bent, and the upper and lower portions extend linearly in the vertical 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 , generating stress inside the probe 20 .

[0021] Figure 3 yes Figure 2 AA cross-sectional view, and is a cross-sectional view perpendicular to the longitudinal direction Z of the probe 20. Figure 3The left-right direction of the paper is the buckling direction X.

[0022] 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.

[0023] like Figure 3 As shown, a plurality of deformation regions 8 and skeleton regions 9 are formed on the side surfaces 20S perpendicular to the two surfaces of the probe 20 perpendicular to the bending direction X of the high resistance portion H. The deformation region 8 refers to a region where the reference plane 20SB, which is the original plane of the probe card, is deformed and formed into a depression. In addition, the skeleton region 9 represents a region connecting the plurality of deformation regions 8. In addition, the boundary between the deformation region 8 and the skeleton region 9 is represented by an edge line 10.

[0024] exist Figure 2 , Figure 3 In FIG. 1 , an example is shown in which a plurality of pentagonal prism-shaped depressions are provided on the reference plane 20SB, which is the original plane, as the deformation region 8. The skeleton region 9 is a portion of the plane between the deformation regions 8. The plurality of pentagonal prism-shaped deformation regions 8 are provided in two rows along the length direction Z of the probe 20, and each row is configured such that the ridges 10 of the plurality of deformation regions 8 are arranged along the length direction on both ends of the buckling direction X of the side surface 20S.

[0025] Figure 4 2 is a side view of the probe 20 and is a diagram showing the positional relationship of the deformation regions 8 arranged in two rows. The two rows of deformation regions 8 are arranged at different positions in the longitudinal direction Z of the probe 20. In addition, in the rows (here, two rows) adjacent to each other in the buckling direction X, the pentagonal prism shape of the deformation region is reversed in the buckling direction X. Figure 4 In the figure, the imaginary line L1 connecting the right ends of each deformation area 8 in the left column exists on the right side of the center line O in the bending direction X of the side 20S, and the imaginary line L2 connecting the left ends of each deformation area 8 in the right column exists on the left side of the center line O in the bending direction X of the side 20S.

[0026] By arranging the deformable regions 8 in each row in this manner, on the side surface 20S of the high resistance portion H of the probe 20, as shown in FIG. Figure 2As shown, side beams 20SB1 and 20SB2 extending along the length direction Z of the probe 20 are formed on both sides of the buckling direction X. In addition, a skeleton region 91 is formed in the center of the side surface 20S of the probe 20 so that the deformation regions 8 arranged in two rows along the length direction Z are formed in a zigzag shape and extend along the length direction Z. The length P1 of the skeleton region 91 is longer than the length of the side beams 20SB1 and 20SB2, that is, the length P2 of the portion of the probe 20 in the length direction Z where the deformation regions 8 are formed.

[0027] Therefore, when two adjacent deformation regions 8 (each belonging to a different column) in the buckling direction X are observed along the longitudinal direction Z of the probe 20, a portion of each deformation region 8 (protrusion 8T in the buckling direction X) appears to overlap with each other.

[0028] Here, when comparing probe A having no deformable region 8 and probe 20 having deformable regions 8 on the front and back sides, probe 20 having deformable regions 8 has a smaller needle pressure relative to the overdrive amount.

[0029] In addition, the effects that can be obtained by the deformation region 8 were analyzed. The maximum stress of the probe was calculated based on the finite element method (FEM) for the probe A without a depression (smooth surface) and the probe 20 with a pentagonal prism-shaped depression. The result showed that when a force is applied from the outside, the stress is concentrated on the ridgeline 10 at the boundary between the deformation region 8 and the skeleton region 9. In addition, it was found that by forming the bottom surface of the deformation region 8 into a flat shape, the stress is concentrated on the ridgeline 10 at the boundary between the deformation region 8 and the skeleton region 9.

[0030] This means that when the deformation region 8 is formed by a polygonal column-shaped depression, stress concentration occurs at each vertex of the polygon, and therefore, when an external force is applied, the stress can be dispersed to each vertex.

[0031] By disposing the deformable region 8 in the high resistance portion H contributing to the maintenance of the mechanical strength of the probe 20 as described above, the length of the skeleton region 91 can be extended, and the stress concentration site can be dispersed to reduce the needle pressure of the probe 20 .

[0032] The probe 20 is made using the so-called MEMS (Micro Electro Mechanical Systems) technology (probe intermediate formation process). MEMS technology is a technology that uses photolithography technology and sacrificial layer etching technology to make 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 make a three-dimensional structure.

[0033] In the formation process of each layer, known plating techniques 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 substrate surface. Such a process is called electroplating, which is a wet process in which the substrate is immersed in an electrolyte. Therefore, after the plating process, a drying process is performed to obtain a probe intermediate. In addition, after the drying process, the part of the lower front end is ground by grinding (grinding process), and a contact portion 20c is formed.

[0034] Figure 5 2 is a cross-sectional view showing a modified example of the probe 20. As shown in the figure, the thickness of the high resistance portion H on the side where the deformation region 8 is not provided can be made smaller than the thickness on the side 20S where the deformation region 8 is provided. In this case, the resistance of the probe can be reduced.

[0035] According to the probe card probe of the first embodiment, by configuring the deformation region 8 as described above in the high resistance portion H that helps maintain the mechanical strength of the probe 20, the length of the skeleton region 91 can be extended, the stress concentration site can be dispersed, and the needle pressure of the probe 20 can be reduced. In addition, for the same needle pressure, the total length of the probe 20 can be reduced. In addition, the columns of the deformation region 8 can also be three or more. In addition, the deformation region 8 can also be configured only on one side 20S.

[0036] Implementation method 2. Hereinafter, the probe card probe of the second embodiment will be described focusing on the parts different from the first embodiment. In this embodiment, a modification example of the deformation region 8 will be described. Figure 6 This is a cross-sectional view perpendicular to the longitudinal direction of the probe 20 of the second embodiment. The left-right direction of the paper is the buckling direction X. This is different from the first embodiment in that the elastic high resistance portion H is penetrated to the low resistance portion L having a low resistance.

[0037] In the first embodiment, the deformable region 8 does not penetrate the high resistance portion H. In the second embodiment, the deformable region 8 penetrates the high resistance portion H, so that the low resistance portion L can be seen from the side surface 20S of the probe 20. With such a structure, the skeleton region 91 can further exert elasticity, thereby further reducing the needle pressure.

[0038] Implementation method three. Hereinafter, the probe card probe of the third embodiment will be described centering on the parts different from the second embodiment. In this embodiment, a modification example of the deformation region 8 will be described. Figure 7 2 is a cross-sectional view perpendicular to the length direction of the probe 20 of the third embodiment. In the third embodiment, as in the second embodiment, the deformation region 8 penetrates the high resistance portion H. In addition, in the third embodiment, an intermediate layer M (third metal layer) is provided between the high resistance portion H and the low resistance portion L. In addition, the deformation region 8 is not provided in the intermediate layer M.

[0039] In the second embodiment, the exposed low resistance portion L must be made of a material that does not melt when the sacrificial layer is etched as an option, but by providing an intermediate layer M that does not melt when the sacrificial layer is etched to protect the low resistance portion L from melting, the range of options for the material of the low resistance portion L is expanded. The material of the intermediate layer M can be a material with a low Young's modulus that does not melt when the sacrificial layer is etched and has less stress relative to deformation, such as palladium, platinum, etc., and the intermediate layer M can be provided according to the required needle pressure and length of the probe 20.

[0040] According to the probe card probe of the second embodiment, the range of options for the material that can be used for the low resistance portion L increases, so that a probe having lower resistance than that of the second embodiment and more flexibility than that of the first embodiment can be realized.

[0041] Figure 8 2 is a cross-sectional view showing a modified example of the probe 20. Figure 8 As shown, the high resistance portion H is provided only on the side surface 20S where the deformation region 8 is provided. In this case, if a metal layer is formed in the Y direction by MEMS, there is an effect that the number of steps can be reduced.

[0042] Implementation method four. Hereinafter, a probe card probe according to a fourth embodiment will be described with reference to the drawings. In this embodiment, another example of the deformation region 8 will be described. Fig. 9 A~ Fig. 9 C is a diagram showing changes in the deformation region 8 . like Fig. 9As shown in FIG. 8A , the triangular prism-shaped deformation regions 8 may be inverted so as to alternately protrude toward the center of the side surface 20S and arranged in two rows along the longitudinal direction Z of the probe 20 .

[0043] In addition, if Fig. 9 As shown in FIG. 2B , the hexagonal prism-shaped deformation regions 8 having two sides parallel to the buckling direction X of the probe 20 and two sides parallel to the longitudinal direction Z when viewed along the buckling direction X may be alternately inverted in the buckling direction X and arranged in two rows along the longitudinal direction Z of the probe 20 .

[0044] In addition, if Fig. 9 As shown in FIG. 3 , when viewed along the buckling direction X, the deformation region 8 of the triangular prism in the shape of a fish cake (semi-cylindrical shape) may be reversed in a manner that alternately protrudes toward the central side of the side surface 20S, and two rows are arranged along the length direction Z of the probe 20. In either case, the front end of the deformation region protruding along the buckling direction X needs to be present at a position exceeding the central line O in the buckling direction of the side surface 20S, which is the same as in the first embodiment. Thus, the same effect as in the first embodiment is achieved.

[0045] Implementation method five. Hereinafter, a probe card probe according to a fifth embodiment will be described with reference to the drawings. In this embodiment, another example of the deformation region 8 will be described. Fig.10 A. Fig.10 B. Fig.10 C. Fig.11 1 is a diagram showing changes in the deformation region 8 . The deformation region 8 can also be Fig.10 The shape of the triangular pyramid shown in A, Fig.10 The pentagonal pyramid shown in B and Fig.10 The shape of the bottom surface shown in C is similar to the shape of the ridgeline 10 of the deformation region 8 and is smaller than the shape of the ridgeline 10. That is, the central portion 8C of the deformation region 8 is a plane, and the surrounding portion surrounding the central portion 8C is an inclined surface SL that is inclined in a manner that expands toward the side surface 20S. The width of the skeleton region 91 gradually increases toward the plane 8F, thereby increasing the strength of the skeleton region 91. The probe card probe of this fifth embodiment also has the same effect as the first to fourth embodiments.

[0046] 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

[0047] 100 probe card; 1 frame; 10 ridge; 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; 20SB1, 20SB2 side beams; 20m central portion; 20S side; 20SB reference surface; 20t terminal portion; 8 deformation region; 8T protrusion; 9, 91 skeleton region; C electrode; H high resistance portion; L low resistance portion; M middle layer; O central line; TC test connection electrode; W semiconductor wafer; P1, P2 length; 8C central portion; SL inclined surface; X buckling direction; Y direction perpendicular to buckling direction X; Z length direction.

Claims

1. A probe for a probe card, characterized in that: The probe includes, on at least one of two side surfaces perpendicular to two surfaces perpendicular to the buckling direction of the probe: a plurality of deformation regions, wherein the plurality of deformation regions are depressions with respect to the side surface, which are arranged in a row and spaced apart in a longitudinal direction of the probe and include two rows of depressions spaced apart; and a sawtooth-shaped skeleton region, the skeleton region being located between the plurality of deformation regions in the two columns, The length of the framework region is longer than the length of the probe in the longitudinal direction.

2. The probe card probe according to claim 1, wherein: When two of the deformation regions adjacent to each other in the buckling direction are observed along the length direction of the probe, parts of the respective deformation regions appear to overlap with each other.

3. The probe for a probe card according to claim 1, wherein: The two deformation regions adjacent to each other in the buckling direction have shapes that are inverted in the buckling direction.

4. The probe for a probe card according to claim 1, wherein: The deformed region is any one of a triangle, a pentagon, a hexagon or a kamaboko shape, and in the two adjacent columns, the deformed region of one column has a protrusion protruding toward the other column.

5. The probe for a probe card according to claim 1, wherein: The bottom surface of the depression in the deformation region is a flat surface, and the peripheral portion surrounding the bottom surface is an inclined surface that is inclined so as to expand toward the side surface.

6. The probe for a probe card according to any one of claims 1 to 5, characterized in that: The probe comprises: a first metal layer on the inner side with lower resistance; and a second metal layer, the second metal layer is located outside the first metal layer, is harder than the first metal layer and has elasticity, The deformation region is formed in the second metal layer.

7. The probe for a probe card according to claim 6, wherein: The deformed region penetrates the second metal layer.

8. The probe for a probe card according to claim 7, wherein: A third metal layer is included between the first metal layer and the second metal layer.

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