Alloy material and contact probe

Abstract

This invention provides an alloy material and a contact probe capable of suppressing casting defects. In the alloy material of this invention, when the weight percentage of silver (Ag) is set as X wt%, the weight percentage of copper (Cu) is set as Y wt%, and the weight percentage of platinum (Pt) is set as Z wt%, X, Y, and Z are within the composition range bounded by line segments connecting the points of the following compositions (X=75, Y=5, Z=20), (X=20, Y=5, Z=75), (X=5, Y=20, Z=75), (X=5, Y=60, Z=35), and (X=75, Y=13, Z=12), and this composition range includes the values ​​on the line segments; and it contains ruthenium (Ru) and / or rhenium (Re), with a combined content of 0.05 wt% or more and 1.0 wt% or less; the remainder consists of unavoidable impurities.

Description

Technical Field

[0001] This invention relates to an alloy material and a contact probe. Background Technology

[0002] Traditionally, when performing continuity or operational characteristic checks on objects such as semiconductor integrated circuits or liquid crystal panels, conductive contact probes are used to electrically connect the object under inspection to a signal processing device on a circuit board for outputting inspection signals. For accurate continuity or operational characteristic checks, it is essential to reliably input and output inspection signals via contact probes.

[0003] Contact probes are used to repeatedly contact objects being inspected, such as semiconductor integrated circuits or liquid crystal display devices. Therefore, the materials used for contact probes must be durable. As a material for improving durability, a high-hardness material is known, which is mainly composed of platinum (Pt) and contains 0.1-14% ruthenium (Ru), 0.1-14% iridium (Ir), 0.1-5.0% silver (Ag), and 0.1-5.0% copper (Cu) by weight (see, for example, Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2006-70337 Summary of the Invention

[0005] Furthermore, contact probes are manufactured through casting. During the crystal growth process in casting, dendritic crystals, or dendrites, are formed. If the molten metal is not supplied to the spaces between these dendrites, gaps known as shrinkage cavities are created. These shrinkage cavities lead to casting defects in the manufactured product.

[0006] The present invention was made in view of the above circumstances, and its object is to provide an alloy material and a contact probe capable of suppressing casting defects.

[0007] To address the aforementioned problems and achieve the objective, in the alloy material of the present invention, when the weight percentage of silver (Ag) is set as X wt%, the weight percentage of copper (Cu) is set as Y wt%, and the weight percentage of platinum (Pt) is set as Z wt%, X, Y, and Z are within the composition range bounded by line segments connecting the points of the following compositions (X=75, Y=5, Z=20), (X=20, Y=5, Z=75), (X=5, Y=20, Z=75), (X=5, Y=60, Z=35), and (X=75, Y=13, Z=12), and the composition range includes the values ​​on the line segments; and it contains ruthenium (Ru) and / or rhenium (Re), the total content of which is in the range of 0.05 wt% or more and 1.0 wt% or less; the remainder consists of unavoidable impurities.

[0008] Furthermore, in the alloy material of the present invention, X, Y, and Z are within a composition range bounded by line segments connecting the points of the following components (X=75, Y=13, Z=12), (X=75, Y=5, Z=20), (X=60, Y=5, Z=35), (X=27, Y=13, Z=60), (X=5, Y=35, Z=60), (X=5, Y=40, Z=55), and (X=35, Y=40, Z=25), and the composition range includes the values ​​on the line segments.

[0009] Furthermore, in the alloy material of the present invention, X, Y, and Z are within a composition range bounded by line segments connecting the points of the following components (X=68, Y=11, Z=21), (X=35, Y=11, Z=54), (X=21, Y=25, Z=54), (X=21, Y=39, Z=40), (X=36, Y=39, Z=25), and (X=48, Y=31, Z=21), and the composition range includes the values ​​on the line segments.

[0010] Furthermore, the alloy material of the present invention, according to the above invention, comprises at least one of the additive elements consisting of nickel (Ni), cobalt (Co) and chromium (Cr), and the total content thereof is in the range of 1.0% by weight or more and 20% by weight or less, and / or comprises at least one of the additive elements consisting of tungsten (W), titanium (Ti), aluminum (Al) and tin (Sn), and the total content thereof is in the range of 0.01% by weight or more and 3.0% by weight or less.

[0011] In addition, at least a portion of the components of the contact probe of the present invention are formed of the alloy material of the present invention described above.

[0012] According to the present invention, it can suppress casting defects. Attached Figure Description

[0013] Figure 1 This is a perspective view showing the structure of a probe unit according to an embodiment of the present invention.

[0014] Figure 2 This is a cross-sectional view showing the structure of the main part of the probe unit according to an embodiment of the present invention.

[0015] Figure 3 This is a graph illustrating the content ratio of copper (Cu), silver (Ag), and platinum (Pt) in one embodiment of the present invention.

[0016] Figure 4 This is a partial cross-sectional view showing the structure of the main part of the probe unit when inspecting a semiconductor integrated circuit.

[0017] Figure 5This is a diagram illustrating the shape of the ingot used for microstructure observation.

[0018] Figure 6 It is a diagram showing a CCD (Charge Coupled Device) image used to illustrate defects caused by added elements.

[0019] Figure 7 This is a diagram showing an SEM (Scanning Electron Microscope) image used to illustrate defects caused by added elements.

[0020] Figure 8 yes Figure 7 An enlarged view of region R1 shown.

[0021] Figure 9 This is a diagram (one of) showing a backscattered electron image and an elemental mapping image used to illustrate defects caused by added elements.

[0022] Figure 10 This is a diagram (II) showing a backscattered electron image and an elemental mapping image used to illustrate defects caused by added elements.

[0023] Figure 11 It is a diagram showing a backscattered electron image and an elemental mapping image used to illustrate the shape of powder containing added elements.

[0024] Symbol Explanation 1: Probe Unit 2: Contact probe (probe) 3: Probe mount 21: First plunger 21a: Front end 22: Second plunger 23: Coil spring 23a: Tightly wound section 23b: Sparse winding section 31: First component 32: Second component 33, 34: Retaining holes 100: Semiconductor integrated circuits 101: Connecting electrodes 200: Circuit board 201: Electrode Detailed Implementation

[0025] The embodiments for carrying out the present invention will now be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below. Furthermore, the figures referenced in the following description are merely schematic representations of shapes, sizes, and positional relationships to the extent that the content of the present invention can be understood. Therefore, the present invention is not limited to the shapes, sizes, and positional relationships illustrated in the figures.

[0026] Implementation Figure 1 This is a perspective view showing the structure of a probe unit according to an embodiment of the present invention. Figure 1 The probe unit 1 shown is a device used to perform electrical characteristic checks on the semiconductor integrated circuit 100, which is the object of inspection. It is a device that electrically connects the semiconductor integrated circuit 100 to the circuit board 200 that outputs inspection signals to the semiconductor integrated circuit 100.

[0027] The probe unit 1 includes: a conductive contact probe 2 (hereinafter referred to as "probe 2"), which is in contact with the electrodes of two different objects to be contacted, namely the semiconductor integrated circuit 100 and the circuit board 200, at both ends in the length direction; a probe holder 3, which houses and holds a plurality of probes 2 according to a prescribed pattern; and a seat member 4, which is disposed around the probe holder 3 to suppress the positional displacement of the semiconductor integrated circuit 100 that is in contact with the plurality of probes 2 during inspection.

[0028] In this embodiment, the electrodes of the semiconductor integrated circuit 100 are BGAs (Ball Grid Arrays) formed using solder.

[0029] Figure 2 This is a cross-sectional view showing the structure of the main parts of a probe unit according to an embodiment of the present invention. The probe 2 is formed using a conductive material and includes: a first plunger 21 that contacts the electrodes of the semiconductor integrated circuit 100 during inspection; a second plunger 22 that contacts the electrodes of a circuit board 200 having an inspection circuit; and a helical spring 23 disposed between the first plunger 21 and the second plunger 22, connecting the first plunger 21 and the second plunger 22 in a retractable manner. Figure 2 In the probe 2, the first plunger 21, the second plunger 22, and the helical spring 23 share the same axis. That is, the central axes of the first plunger 21, the second plunger 22, and the helical spring 23 are located on the same straight line. Furthermore, "same axis" includes deviations caused by individual deformation of components or manufacturing errors. When the probe 2 contacts the semiconductor integrated circuit 100, the extension and retraction of the helical spring 23 in the axial direction can mitigate the impact on the electrodes of the semiconductor integrated circuit 100, while simultaneously applying a load to the semiconductor integrated circuit 100 and the circuit board 200.

[0030] The first plunger 21 has a front end portion 21a, which has a gradually tapering front end shape and contacts the electrodes of the semiconductor integrated circuit 100. The first plunger 21 can move in the axial direction by the extension and retraction of the helical spring 23, and is subjected to a force in the direction of the semiconductor integrated circuit 100 by the elastic force of the helical spring 23, thus contacting the electrodes of the semiconductor integrated circuit 100.

[0031] In this embodiment, the case where the front end portion 21a is crown-shaped with multiple claws is described, but the front end portion 21a may also be in other shapes such as conical or spherical.

[0032] The first plunger 21 is formed using an alloy material.

[0033] Figure 3 This is a diagram illustrating the content ratio of copper (Cu), silver (Ag), and platinum (Pt) in one embodiment of the present invention. The alloy material forming the first plunger 21 has an Ag-Cu-Pt composition as follows: Figure 3 The combinations within the region R shown.

[0034] Specifically, in the alloy material, when the weight percentage of silver (Ag) is set as X wt%, the weight percentage of copper (Cu) is set as Y wt%, and the weight percentage of platinum (Pt) is set as Z wt%, X, Y, and Z are within the composition range (region R) enclosed by the line segments connecting the points of the following compositions (X=75, Y=5, Z=20), (X=20, Y=5, Z=75), (X=5, Y=20, Z=75), (X=5, Y=60, Z=35), and (X=75, Y=13, Z=12), and this composition range includes the values ​​on the line segments, with the remainder consisting of unavoidable impurities. Regarding the range of components, it is preferred that X, Y, and Z are within the range (region R') enclosed by the line segments connecting the points of the following components (X=75, Y=13, Z=12), (X=75, Y=5, Z=20), (X=60, Y=5, Z=35), (X=27, Y=13, Z=60), (X=5, Y=35, Z=60), (X=5, Y=40, Z=55), and (X=35, Y=40, Z=25). More preferably, X, Y, and Z are located within the area (region R) enclosed by the line segments connecting the points (X=68, Y=11, Z=21), (X=35, Y=11, Z=54), (X=21, Y=25, Z=54), (X=21, Y=39, Z=40), (X=36, Y=39, Z=25), and (X=48, Y=31, Z=21).

[0035] Here, if the alloy material contains more than 75% by weight of Ag, there will be less precipitated phase transformation and lower hardness. Conversely, if Ag is less than 5% by weight, the resistivity will increase and the resistance to Sn reactivity will decrease.

[0036] Furthermore, if the alloy material contains more than 60% Cu by weight, it may be easily oxidized at high temperatures (around 175°C in this case), leading to poor appearance. Conversely, if Cu is less than 5% by weight, there will be less precipitated phase and lower hardness.

[0037] Furthermore, as an alloy material, Pt has a higher resistivity than Ag and Cu. Therefore, if Pt contains more than 75% by weight, the resistivity of the alloy material increases. Conversely, if Pt is less than 10% by weight, there is less precipitated phase transformation and the hardness decreases.

[0038] In addition to the aforementioned Ag-Cu-Pt, the alloy material also contains ruthenium (Ru) and / or rhenium (Re), with a combined content ranging from 0.05% to 1.0% by weight. If the combined content of Ru and Re is less than 0.05% by weight, the amount of nuclei generated will be insufficient, potentially failing to suppress dendrite formation. Conversely, if the combined content of Ru and Re is greater than 1.0% by weight, the excessive amount of nuclei will act as inclusions, potentially increasing the resistivity of the alloy material or reducing its workability.

[0039] Furthermore, the alloy material is configured such that Ru and / or Re are added to the aforementioned Ag-Cu-Pt, and the remainder consists of unavoidable impurities. However, it can also be configured to contain at least one of the additive elements group consisting of nickel (Ni), cobalt (Co), and chromium (Cr), with a total content in the range of 1.0% by weight or more and 20% by weight, and / or contain at least one of the additive elements group consisting of tungsten (W), titanium (Ti), aluminum (Al), and tin (Sn), with a total content in the range of 0.01% by weight or more and 3.0% by weight. In this embodiment, these additive elements increase the hardness of the alloy material. On the other hand, if these additive elements exceed the upper limit, the resistivity of the alloy material may increase.

[0040] Return to Figure 2 The second plunger 22 has a gradually tapering front end shape, which contacts the electrodes of the circuit board 200. The second plunger 22 is formed, for example, using the same material as the first plunger 21 or other conductive materials. The second plunger 22 is movable in the axial direction by the extension and retraction of the helical spring 23, and is subjected to a force in the direction of the circuit board 200 by the elastic force of the helical spring 23, thereby contacting the electrodes of the circuit board 200.

[0041] The helical spring 23 has: a tightly wound portion 23a, which is mounted on the base end side of the first plunger 21; and a sparsely wound portion 23b, which is wound at predetermined intervals, and is mounted on the base end side of the second plunger 22. The helical spring 23 is, for example, wound from a single conductive wire. The wire may be, for example, stainless steel wire or piano wire.

[0042] The end of the tightly wound portion 23a is pressed into the base end of the first plunger 21, for example. On the other hand, the end of the sparsely wound portion 23b is pressed into the base end of the second plunger 22. Furthermore, the first plunger 21 and the second plunger 22 are joined to the helical spring 23 by the spring's winding force and / or by welding. The probe 2 extends and retracts in the axial direction due to the extension and retraction of the sparsely wound portion 23b.

[0043] The probe holder 3 is formed using insulating materials such as resin, machinable ceramics, and silicon, and is located in... Figure 2 The upper part 31 and the lower part 32 are stacked together. In the first part 31 and the second part 32, the same number of holding holes 33 and 34 are formed for accommodating multiple probes 2, respectively, and the holding holes 33 and 34 for accommodating probes 2 are aligned with each other. The positions of the holding holes 33 and 34 are determined according to the wiring pattern of the semiconductor integrated circuit 100.

[0044] Both retaining holes 33 and 34 are stepped holes whose diameter varies along the through direction. Specifically, retaining hole 33 consists of a small-diameter portion 33a with an opening on the upper end face of probe holder 3, and a large-diameter portion 33b with a diameter larger than the small-diameter portion 33a. Similarly, retaining hole 34 consists of a small-diameter portion 34a with an opening on the lower end face of probe holder 3, and a large-diameter portion 34b with a diameter larger than the small-diameter portion 34a. The shapes of these retaining holes 33 and 34 are determined according to the structure of the probe 2 to be housed.

[0045] Figure 4 This diagram illustrates the state when the semiconductor integrated circuit 100 is inspected using the probe holder 3. During inspection of the semiconductor integrated circuit 100, the helical spring 23 is compressed along its length due to the contact load from the semiconductor integrated circuit 100 and the circuit board 200. The inspection signal supplied from the circuit board 200 to the semiconductor integrated circuit 100 during inspection travels from the electrode 201 of the circuit board 200 through the second plunger 22, the tightly wound portion 23a, and the first plunger 21 of the probe 2 to the connection electrode 101 of the semiconductor integrated circuit 100.

[0046] In the embodiment described above, the plunger is made using an alloy material configured such that, when the weight percentage of silver (Ag) is X wt%, the weight percentage of copper (Cu) is Y wt%, and the weight percentage of platinum (Pt) is Z wt%, X, Y, and Z are within the composition range bounded by line segments connecting the points of the following compositions: (X=75, Y=5, Z=20), (X=20, Y=5, Z=75), (X=5, Y=20, Z=75), (X=5, Y=60, Z=35), and (X=75, Y=13, Z=12). This composition range includes the values ​​on the line segments. In addition to the Ag-Cu-Pt composition described above, the plunger also contains ruthenium (Ru) and / or rhenium (Re), with a combined content of 0.05 wt% to 1.0 wt%, and the remainder consists of unavoidable impurities. By using this alloy material, casting defects can be suppressed during plunger manufacturing. Furthermore, in contact probes, as long as at least the part that contacts the object being contacted, especially the part that repeatedly contacts and separates from the object being contacted due to repeated use (here, the first plunger 21), is formed of the aforementioned alloy material, it is possible to obtain a contact probe with fewer casting defects and improved durability.

[0047] Example The embodiments of the present invention will be described below. However, the present invention is not limited to these embodiments.

[0048] Organizational observation The morphology of dendrites and casting pores caused by added elements was observed.

[0049] First, refer to Figure 5 The ingots used for tissue observation are described. Figure 5 This is a diagram illustrating the shape of the ingot used for microstructure observation. Figure 5 The ingot 50 shown is obtained by heat treatment at 940°C for 1 hour after casting. It has a cylindrical shaft portion 51 and a frustum-shaped riser portion 52 connected to one end of the shaft portion 51 in the longitudinal direction. The diameter r1 of the shaft portion 51 is set to 12 mm, and the length L1 of the shaft portion 51 in the longitudinal direction is set to 165 mm.

[0050] Fifty ingots with different compositions were prepared as samples for microstructure observation. The prepared samples are shown below.

[0051] Sample 1: 0.5 wt% iridium (Ir) added to 30 wt% Ag - 20 wt% Cu - 49.5 wt% Pt Sample 2: Add 0.5 wt% ruthenium (Ru) to a mixture of 30 wt% Ag, 20 wt% Cu, and 49.5 wt% Pt. Sample 3: 0.5 wt% rhenium (Re) added to 30 wt% Ag - 20 wt% Cu - 49.5 wt% Pt Sample 4: 30 wt% Ag, 20 wt% Cu, 50 wt% Pt (no added elements) Cross-sectional image observation Figure 6 It is a diagram representing a CCD (Charge Coupled Device) image used to illustrate defects caused by added elements. Figure 6 The CCD images shown are obtained by capturing a portion of the axial cross-section of each sample. Figure 6 The black spots observed indicate casting defects. For each sample, the center of the ingot (see [reference]) was analyzed using a WinROOF2021 manufactured by Mitani Corporation. Figure 6 A 5mm × 5mm area near the dashed line (as indicated by the dashed line) is binarized to extract the defect area, and the defect rate is calculated. The defect rate is obtained by calculating the ratio of the defect area to the area of ​​the entire region. Figure 6 The defect rates of each sample in the CCD images shown are as follows.

[0052] Sample 1 (with Ir added): 7.1% Sample 2 (with Ru added): 3.6% Sample 3 (with Re added): 0.4% Sample 4 (no additives): 11.1% SEM image observation Figure 7 This is a diagram representing a SEM (Scanning Electron Microscope) image used to illustrate defects caused by added elements. Figure 8 yes Figure 7 An enlarged view of region R1 shown. Figure 7 The SEM images shown were obtained using a ZEISS Sigma scanning electron microscope (manufactured by ZEISS Corporation), with a magnification of 500x, an accelerating voltage of 21.00 kV, and a working distance of 10.00 mm, to capture a portion of the axial cross-section of each sample. In the SEM images, gray areas represent the α phase (platinum-rich), black areas represent the β phase (silver-rich), and white areas represent Re (see [link to image]). Figure 8 ).like Figure 7 As shown, sample 1 with added Ir exhibits coarse dendritic structure. Furthermore, dendritic structure also appears in sample 4 without added elements. In contrast, dendritic structure formation is suppressed in samples 2 and 3 with added Ru and Re, respectively. Moreover, in sample 3 with added Re, as... Figure 8 As shown, the α phase contains rod-shaped tissue (Re).

[0053] EPMA Observation Then, the distribution and segregation of the added elements were observed using ingots from each sample. For the images used for observation, backscattered electron images were acquired using energy dispersive X-ray spectrometry (EDS) with SEM-EDX, and mapping images of the added elements were generated using an electron probe microanalyzer (EPMA). An XFlash 5010 (manufactured by Bruker) was used for EDS, and a JXA-8530F (manufactured by JEOL) was used for EPMA.

[0054] Figure 9 and Figure 10 It is a diagram showing a backscattered electron image and an elemental mapping image used to illustrate defects caused by added elements. Figure 9 This represents a backscattered electron image and elemental mapping image at low magnification. Figure 10 This represents a high-magnification backscattered electron image and elemental mapping image. Based on... Figure 9 and Figure 10 It can be seen that Ir is dissolved throughout the dendrites, while Re and Ru are distributed in a fine and non-uniform manner. This is believed to be because the addition of Re and Ru acts as solidification nuclei, thereby inhibiting the formation of dendrites.

[0055] Powder shape with added elements In addition, the powder shape of the additive elements added before Ag-Cu-Pt was observed. Figure 11 This is a diagram showing a backscattered electron image (powder appearance) and an elemental mapping image (coagulation structure) used to illustrate the powder shape of added elements. For example... Figure 11 As shown, the morphology of the powder and the solidified structure differs regardless of the added element, suggesting that the added element dissolves during melting. Subsequently, Re and Ru precipitate out finely during solidification, becoming the nucleus of the solidified structure.

[0056] As explained above, Re and Ru, as additive elements, can be considered as nuclei of the solidification structure, suppressing dendrite formation and thus producing castings with a lower defect rate. On the other hand, Ir, dissolved throughout the dendrites, has a smaller effect in suppressing dendrite formation, resulting in a higher defect rate compared to Re and Ru.

[0057] The foregoing has described the methods for implementing the present invention, but the present invention should not be limited to the above embodiments. In the embodiments, a contact probe was described as an example, but the alloy material of the present invention can be used for any component of electrical or electronic equipment that comes into contact with an element containing Sn. In this case, the component only needs to be formed of the alloy material of the present invention for at least the portion that contacts the element.

[0058] Furthermore, the structure of probe 2 described in the embodiment is only an example, and the above-mentioned alloy material can be applied to various probes known in the past. For example, it is not limited to the probe composed of a plunger and a helical spring as described above, but may also be a probe with a tube component, a spring needle, or a linear probe that obtains load by bending a metal wire into an arc shape, or a connecting terminal (connector) that connects electrical contacts to each other.

[0059] As described above, the present invention may include various embodiments not described herein, and various design changes may be made without departing from the technical concept defined in the claims.

[0060] As explained above, the alloy material and contact probe of the present invention are suitable for suppressing casting defects.

Claims

1. An alloy material, characterized in that, When the weight percentage of silver (Ag) is set as X wt%, the weight percentage of copper (Cu) is set as Y wt%, and the weight percentage of platinum (Pt) is set as Z wt%, X, Y, and Z lie within the range bounded by line segments connecting the points of the following: (X=75, Y=5, Z=20), (X=20, Y=5, Z=75), (X=5, Y=20, Z=75), (X=5, Y=60, Z=35), and (X=75, Y=13, Z=12), and the range includes the values ​​on the line segments. It contains ruthenium (Ru) and / or rhenium (Re), with a combined content of more than 0.05% by weight and less than 1.0% by weight. The remainder consists of unavoidable impurities.

2. The alloy material according to claim 1, characterized in that, X, Y, and Z lie within a range bounded by line segments connecting the points of the following: (X=75, Y=13, Z=12), (X=75, Y=5, Z=20), (X=60, Y=5, Z=35), (X=27, Y=13, Z=60), (X=5, Y=35, Z=60), (X=5, Y=40, Z=55), and (X=35, Y=40, Z=25), and the range includes the values ​​on the line segments.

3. The alloy material according to claim 2, characterized in that, X, Y, and Z lie within a range bounded by line segments connecting the points of the following: (X=68, Y=11, Z=21), (X=35, Y=11, Z=54), (X=21, Y=25, Z=54), (X=21, Y=39, Z=40), (X=36, Y=39, Z=25), and (X=48, Y=31, Z=21), and the range includes the values ​​on the line segments.

4. The alloy material according to claim 1, characterized in that, It contains at least one of the additive elements consisting of nickel (Ni), cobalt (Co), and chromium (Cr), and the total content of these elements is in the range of 1.0% by weight or more and 20% by weight or less. and / or It contains at least one of the additive elements consisting of tungsten (W), titanium (Ti), aluminum (Al) and tin (Sn), and the total content of these elements is in the range of more than 0.01% by weight and less than 3.0% by weight.

5. A contact probe, characterized in that, At least a portion of the component is formed of the alloy material according to any one of claims 1 to 4.

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