Alloy, alloy wire rod obtained using said alloy, alloy wire rod for probe pin obtained using said alloy wire rod, and method for producing alloy wire rod for probe pin

Abstract

The purpose of the present invention is to provide: an alloy that achieves both the high hardness required for probe pins and the ability to be processed into an alloy wire rod; an alloy wire rod obtained using the alloy; an alloy wire rod for a probe pin obtained using the alloy wire rod; and a method for producing the alloy wire rod for a probe pin. To achieve this purpose, adopted are: an alloy characterized by including 5.0-15.0 mass% Ag, 48.2-58.3 mass% Pd, 34.6-42.3 mass% Cu, 0.05-0.17 mass% B, 0.3-1.5 mass% Zn, and 0.006-0.10 mass% Al, with the remainder being unavoidable impurities; an alloy wire rod obtained using the alloy; an alloy wire rod for a probe pin obtained using the alloy wire rod; and a method for producing the alloy wire rod for a probe pin.

Description

An alloy, an alloy wire obtained using the alloy, an alloy wire for probe pins obtained using the alloy wire, and a method for producing an alloy wire for probe pins

[0001] The present invention relates to an alloy, an alloy wire obtained using the alloy, an alloy wire for probe pins obtained using the alloy wire, and a method for producing an alloy wire for probe pins.

[0002] Conventionally, probe cards and contact probes have been known as probes for electrical inspection of semiconductor components having narrow-pitch electrodes such as semiconductor integrated circuits and semiconductor packages. These inspection probes use a plurality of probe pins formed from an alloy wire with a small wire diameter (also referred to as a fine metal wire or fine alloy wire). Furthermore, such small-diameter alloy wires used for probe pins are also used as conductor materials for electric wires and cables used in electronic devices such as mobile devices and industrial robots, and medical devices. When such an alloy wire for probe pins is used as a probe pin, it repeatedly comes into contact with the electrode of a component to be inspected with an appropriate load, so it is required to have well-balanced performance such as high hardness and bendability.

[0003] In response to such requirements for probe pin materials, for example, Patent Document 1 discloses a probe pin material comprising Ag, Pd, Cu, B as a first additive element, at least any one element selected from Zn, Bi, and Sn as a second additive element, and unavoidable impurities, as a probe pin material that is excellent in resistance value and hardness (wear resistance) and has improved bending resistance. It is disclosed that the Vickers hardness of the probe pin material is 380 HV or more and 580 HV or less, and the number of 90° bending times is 5 or more.

[0004] Japanese Patent Publication "Patent No. 7072126"

[0005] As shown in the example above, there have been reports of improving the hardness of alloys containing Ag, Pd, and Cu as main components (hereinafter referred to as Ag-Pd-Cu alloys) by adding various metallic elements. However, depending on the alloy composition, this can sometimes reduce the workability of the alloy wire, and as a result, the inventors of the present invention have found that there is room for improvement in achieving both improved alloy hardness and workability of the alloy wire.

[0006] The present invention has been made in view of these circumstances. The present invention aims to provide an alloy that achieves both the high hardness required for probe pins and processability into alloy wire, an alloy wire obtained using said alloy, an alloy wire for probe pins obtained using said alloy wire, and a method for manufacturing the alloy wire for probe pins.

[0007] In order to solve the aforementioned problems, we conducted intensive research and came up with the following alloy, alloy wire obtained using this alloy, alloy wire for probe pins obtained using this alloy wire, and a method for manufacturing the alloy wire for probe pins.

[0008] The first alloy according to the present invention employs an alloy characterized by comprising 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.05 mass% to 0.17 mass% of B, 0.3 mass% to 1.5 mass% of Zn, 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities.

[0009] The second alloy according to the present invention is preferably the first alloy in which B is 0.05 mass% or more and 0.09 mass% or less.

[0010] The third alloy according to the present invention is preferably the first alloy in which B is 0.11 mass% or more and 0.16 mass% or less.

[0011] The fourth alloy according to the present invention is preferably the first alloy having B in an amount of 0.09 mass% or more and 0.16 mass% or less, and Zn in an amount of 1.0 mass% or more and 1.5 mass% or more.

[0012] The fifth alloy according to the present invention employs an alloy characterized by comprising 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.08 mass% to 0.17 mass% of B, 0.3 mass% to 1.3 mass% of Zn, 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities.

[0013] The first alloy wire according to the present invention employs an alloy wire characterized by being obtained using the first alloy.

[0014] The alloy wire according to the present invention preferably has a wire diameter of 1.0 mm or less.

[0015] The alloy wire according to the present invention preferably has a Vickers hardness of 490 HV or more and 600 HV or less.

[0016] The alloy wire according to the present invention preferably has a volume resistivity of 11.5 μΩ·cm or less.

[0017] The alloy wire for probe pins according to the present invention employs an alloy wire for probe pins that is obtained using the alloy wire described above. In addition to the first alloy, the second, third, and fourth alloys can also be used as alloy wires for probe pins.

[0018] The second alloy wire according to the present invention is an alloy wire obtained using the fifth alloy, characterized in that it has a wire diameter of 0.1 mm or less.

[0019] The first method for manufacturing an alloy wire for probe pins according to the present invention employs a method for manufacturing an alloy wire for probe pins characterized by comprising the following steps 1 to 3. Step 1: A metal material containing Ag, Pd, Cu, B, Zn, and Al is heated and melted to obtain an ingot containing 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.05 mass% to 0.17 mass% of B, 0.3 mass% to 1.5 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities. Step 2: The ingot is repeatedly subjected to cold working with a cross-sectional reduction rate of 50% or more, followed by heat treatment, to obtain an alloy wire with a wire diameter of 1.0 mm or less before aging treatment. Step 3: The alloy wire before aging treatment is subjected to aging treatment to obtain an aged alloy wire for probe pins.

[0020] The second method for manufacturing alloy wire for probe pins according to the present invention employs the following method for manufacturing alloy wire for probe pins, comprising steps 1 to 3 below. Step 1: A metal material containing Ag, Pd, Cu, B, Zn, and Al is heated and melted to obtain an ingot containing 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.08 mass% to 0.17 mass% of B, 0.3 mass% to 1.3 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities. Step 2: The ingot is repeatedly subjected to cold working with a cross-sectional reduction rate of 50% or more, followed by heat treatment, to obtain an alloy wire with a wire diameter of 0.1 mm or less before aging treatment. Step 3: The alloy wire before aging treatment is subjected to aging treatment to obtain an aged alloy wire for probe pins.

[0021] According to the present invention, it is possible to provide an alloy that achieves both the high hardness required for probe pins and processability into alloy wire, an alloy wire obtained using the alloy, an alloy wire for probe pins obtained using the alloy wire, and a method for manufacturing the alloy wire for probe pins.

[0022] The following describes the alloy relating to the present invention, the alloy wire obtained using the alloy, the alloy wire for probe pins obtained using the alloy wire, and embodiments of the method for manufacturing the alloy wire for probe pins. It should be noted that the following description merely illustrates one aspect and should not be interpreted as limiting the scope of the description below.

[0023] 1. Alloy The first alloy according to the present invention contains 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.05 mass% to 0.17 mass% of B, 0.3 mass% to 1.5 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al. The sum of each of the above-mentioned compositions is 100 mass%. However, the first alloy according to the present invention may contain unavoidable impurities. If unavoidable impurities are present, the sum of all the above-mentioned metal composition components and the unavoidable impurities is 100 mass%. The first alloy employing this composition possesses both the high hardness required for probe pins and the machinability to be formed into alloy wire.

[0024] The main components of this alloy are Ag (silver), Pd (palladium), and Cu (copper). Cu has good low electrical resistance but low hardness, so Ag and Pd are added to improve hardness and achieve both high hardness and low resistance. In this case, the preferred composition range for achieving high hardness and low resistance is Ag at 5.0 mass% to 15.0 mass%, Pd at 48.2 mass% to 58.3 mass%, and Cu at 34.6 mass% to 42.3 mass%.

[0025] The first component added to the Ag, Pd, and Cu mentioned above is boron (B). By adding B to the Ag-Pd-Cu alloy, the hardness can be improved. The content should be between 0.05 mass% and 0.17 mass%. If the B content is less than 0.05 mass%, the aforementioned effect cannot be obtained. Furthermore, if the B content exceeds 0.17 mass%, the plasticity decreases significantly, and the precipitation of intermetallic compounds, which will be discussed later, is inhibited.

[0026] The second component added to the Ag, Pd, and Cu mentioned above is Zn (zinc). Zn strengthens the grain boundaries by forming intermetallic compounds with the PdCu ordered phase, which is the age-hardening factor of the Ag-Pd-Cu alloy. This improves hardness and wear resistance. The Zn content is between 0.3 mass% and 1.5 mass%. If the Zn content is less than 0.3 mass%, the aforementioned effects cannot be obtained. Furthermore, if the Zn content exceeds 1.5 mass%, the workability decreases, making cold working difficult in the manufacturing process.

[0027] The third component added to the Ag, Pd, and Cu mentioned above is Al (aluminum). Al suppresses grain boundary reactions of precipitates in Ag-Pd-Cu alloys and promotes intragranular formation of precipitates. Furthermore, by adding Al within an appropriate range, the workability of the alloy into alloy wire is improved, and the hardness after aging treatment is also improved. The Al content is between 0.006 mass% and 0.10 mass%. If the Al content is less than 0.006 mass%, the aforementioned effects cannot be obtained. Also, if the Al content exceeds 0.10 mass%, it will actually inhibit the precipitation of intermetallic compounds, resulting in no hardness improvement and a decrease in molten metal flowability.

[0028] Thus, the first alloy according to the present invention is an Ag-Pd-Cu alloy containing B and Zn, and further containing Al in the above-mentioned proportions. The alloy with the above composition has good processability from the alloy to alloy wire, and the alloy wire exhibits improved hardness after aging treatment.

[0029] By employing an alloy containing Ag, Pd, Cu, B, Zn, and Al within the aforementioned ranges, with the remainder being unavoidable impurities, a good balance of high hardness and machinability is achieved. This results in excellent machinability for probe pins and a long lifespan when used as probe pins. Here, unavoidable impurities are not particularly limited as long as they are inevitably mixed in, and they are not necessarily present, but rather may be included as unavoidable impurities. In the case where unavoidable impurities are present, the sum of all the metal composition components related to this invention and the unavoidable impurities is 100 mass%.

[0030] The second alloy according to the present invention is an alloy in which B is 0.05 mass% or more and 0.09 mass% or less in the first alloy. As shown in Table 3 described later, by limiting B to the above range compared to the first alloy, in addition to good hardness and workability, a good (lower) volume resistivity can be obtained.

[0031] The third alloy according to the present invention is an alloy in which B is 0.11 mass% or more and 0.16 mass% or less in the first alloy. As shown in Table 4 later, higher hardness can be obtained by limiting B to the above range compared to the first alloy.

[0032] The fourth alloy according to the present invention is an alloy in which, in the first alloy, B is 0.09 mass% or more and 0.16 mass% or less, and Zn is 1.0 mass% or more and 1.5 mass% or more. As shown in Table 5 described later, by limiting B and Zn to the above ranges compared to the first alloy, a good balance is achieved in which higher hardness is obtained and good volume resistivity is also obtained.

[0033] The fifth alloy according to the present invention contains 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.08 mass% to 0.17 mass% of B, 0.3 mass% to 1.3 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al. The sum of each of the above-mentioned compositions is 100 mass%. However, the fifth alloy according to the present invention may contain unavoidable impurities. If unavoidable impurities are present, the sum of all the above-mentioned metal composition components and the unavoidable impurities is 100 mass%. The fifth alloy, employing this composition, not only possesses the high hardness and processability required for probe pins, but also achieves a bending cycle of 20 or more at a final processing rate of 99% or more. This is due to the effect of adding Al within an appropriate range, which improves the processability from the alloy to alloy wire, and simultaneously improves hardness and bending resistance after aging treatment.

[0034] [Method for measuring composition] The method for measuring the composition of an alloy is not particularly limited, but it can be done using ICP (inductively coupled plasma) emission spectrometers or XRF (X-ray fluorescence) analysis. It can also be measured using analytical methods such as gravimetric analysis, EDX (energy-dispersive X-ray) analysis, or WDX (wavelength-dispersive X-ray) analysis.

[0035] 2. Alloy Wire The alloy wire according to the present invention is obtained using the above-mentioned alloy. Therefore, it possesses the high hardness required for probe pins and is easy to process into alloy wire.

[0036] [Wire Diameter] The wire diameter of the alloy wire according to the present invention is preferably 1.0 mm or less. If the wire diameter exceeds 1.0 mm, its use as a probe pin for electrical testing, such as probe cards and contact probes, becomes extremely limited, and the added value of the alloy wire tends to decrease, which is undesirable. Furthermore, in order to achieve 20 or more bending cycles as described later, it is even more preferable that the wire diameter be 0.1 mm or less. This is because as the wire diameter becomes thinner, the alloy structure becomes finer and the bending resistance improves. If the wire diameter is 0.1 mm, it is possible to achieve 20 or more bending cycles (Table 6 in the examples described later). Also, if the wire diameter is 0.1 mm or less and the final processing rate is 99% or more, it is possible to achieve 20 or more bending cycles in the same way. On the other hand, there is no particular restriction on the lower limit of the wire diameter, but considering the processing accuracy, it is preferable that the wire diameter be 0.020 mm or more.

[0037] [Processability] The final processing rate of the alloy wire rod according to the present invention is preferably 90% or higher. If the final processing rate is less than 90%, the hardness improvement after aging treatment tends not to be sufficient, and the volume resistivity after aging treatment tends to increase. On the other hand, there is no particular upper limit on the final processing rate, but if the final processing rate is high, processing tends to become difficult, and further improvement in hardness cannot be expected, so the final processing rate is preferably 99.99% or lower. Here, the final processing rate is the reduction rate of the cross-sectional area when processed from the final heat treatment to the final wire diameter. The reduction rate of the cross-sectional area is calculated as (cross-sectional area before processing - cross-sectional area after processing) / cross-sectional area before processing × 100%.

[0038] [Vickers Hardness] The Vickers hardness of the alloy wire according to the present invention is preferably 490 HV or more and 600 HV or less. If the Vickers hardness is less than 490 HV, it will be more prone to wear in touchdown tests that involve repeated contact with the object being inspected. It has been reported that a Vickers hardness of 476 HV will break after about 110,000 repeated contacts, while a Vickers hardness of 490 HV will not break even after more than 200,000 contacts, and a Vickers hardness of 530 HV will not break even after more than 230,000 contacts. Furthermore, if the Vickers hardness exceeds 600 HV, it becomes difficult to achieve more than 20 90° bends. Here, the touchdown test is a durability test in which a probe pin is brought into contact with a chip on a semiconductor wafer.

[0039] [Volume Resistivity] The volume resistivity of the alloy wire according to the present invention is preferably 11.5 μΩ·cm or less, more preferably 8.50 μΩ·cm or less, and even more preferably 7.80 μΩ·cm or less. As mentioned above, the alloy wire is used as a probe pin for electrical testing of semiconductor components, etc. Therefore, if the volume resistivity exceeds 11.5 μΩ·cm, the voltage drop due to the current flowing through the probe pin during electrical testing becomes large, resulting in a large measurement error. On the other hand, there is no particular limit on the lower limit of volume resistivity, but since lowering the volume resistivity improves bendability but decreases hardness, it is preferable that the volume resistivity of the alloy wire according to the present invention be 5 μΩ·cm or more.

[0040] [Number of Bending Cycles] An alloy wire obtained using the fifth alloy according to the present invention, having a wire diameter of 0.1 mm or less and a final processing rate of 99% or more, can achieve 20 or more 90° bending cycles in a 90° bending test after aging treatment. Since the number of bending cycles before breakage can be increased by reducing the wire diameter of the alloy wire, it is preferable that the alloy wire has a wire diameter of 0.1 mm or less and a final processing rate of 99% or more. Furthermore, a high number of 90° bending cycles not only means excellent processability but also allows for suitable use in cantilever-type probe pins and the like.

[0041] If the number of 90° bends is less than 20, not only is the processability poor, but the durability is also poor, for example, when used as a cantilever-type probe pin. On the other hand, there is no particular upper limit on the number of 90° bends, but since increasing the number of 90° bends reduces hardness, it is preferable that the number of 90° bends of the alloy wire according to the present invention be about 40 times or less. The 90° bend test is a test in which an alloy wire in a straight state is bent at an angle of approximately 90° in the first step and bent back to a straight state from the state bent at approximately 90° in the second step, which is repeated alternately. Each of the first and second steps is counted as one bend, and the total number of times until the wire breaks is called the number of 90° bends.

[0042] 3. Alloy Wire for Probe Pins The alloy wire for probe pins according to the present invention is obtained using the alloy wire described above. Therefore, it possesses the high hardness required for probe pins. By forming probe pins using this alloy wire, probe pins with high hardness can be obtained. In other words, they can be suitably used as probes for electrical testing of semiconductor components and the like.

[0043] 4. Method for Manufacturing Alloy Wire for Probe Pins The first method for manufacturing alloy wire for probe pins according to the present invention is the method for manufacturing alloy wire for probe pins described above, and comprises the following steps 1 to 3. Step 1: A metal material containing Ag, Pd, Cu, B, Zn, and Al is heated and melted to obtain an ingot containing 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.05 mass% to 0.17 mass% of B, 0.3 mass% to 1.5 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities. Step 2: The ingot obtained in Step 1 is subjected to repeated cold working and heat treatment with a cross-sectional reduction rate of 50% or more to obtain an alloy wire with a wire diameter of 1.0 mm or less before aging treatment. Step 3: The alloy wire obtained in Step 2 before aging treatment is subjected to aging treatment to obtain an aged alloy wire for probe pins.

[0044] By adopting this manufacturing method, it is possible to produce an alloy wire rod for probe pins that achieves both the high hardness required for probe pins and workability into an alloy wire rod.

[0045] [Step 1] Step 1 is a step of manufacturing an ingot as a raw material for obtaining an alloy wire rod for probe pins having a predetermined composition by using a casting technique. Specifically, a metal material blended with Ag, Pd, Cu, B, Zn, and Al is placed in a heat-resistant container and heated to be melted. The atmosphere is not particularly limited, and the heating and melting can be performed in the air, vacuum, an inert gas atmosphere such as nitrogen or argon, or a slightly reducing atmosphere. Next, the molten metal material is poured into a mold, wherein the material contains 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.05 mass% to 0.17 mass% of B, 0.3 mass% to 1.5 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al, with the balance being inevitable impurities, thereby obtaining an ingot. It should be noted that the method is not limited to the above-described method as long as the ingot in step 1 can be obtained, and for example, the ingot may be obtained by using any melting casting method such as a continuous casting method.

[0046] Here, if the Al content exceeds 0.01 mass%, molten metal fluidity decreases, which is not preferable. If the B content exceeds 0.17 mass%, workability is remarkably reduced, making cold working difficult, which is not preferable. Furthermore, if the Zn content exceeds 1.5 mass%, workability is reduced, making cold working difficult, which is not preferable.

[0047] As the manufacturing conditions for heating and melting in this step 1, conventionally known conditions may be used, for example, a melting temperature of 1300°C and an inert gas atmosphere condition may be adopted. However, as long as the metal material can be heated and melted, the conditions are not limited to the above. It should be noted that the slightly reducing atmosphere is a gas obtained by mixing a trace amount of reducing gas such as hydrogen or carbon monoxide into an inert gas, and for example, a gas mixed at a ratio of 95% nitrogen and 5% hydrogen can be used.

[0048] [Step 2] Step 2 is a step for producing an alloy wire rod before aging treatment having a wire diameter of 1.0 mm or less by repeatedly performing cold working with a cross-sectional reduction rate of 50% or more and heat treatment in an inert gas atmosphere or a slightly reducing atmosphere on the ingot obtained in Step 1. Here, the cold working step is a step for forming the ingot into a desired shape and dimensions, and introducing large compressive stress into the alloy to improve the strength and hardness. Specifically, in an environment near room temperature, the ingot obtained in Step 1 is processed using a rolling device, a wire drawing device or the like such that the cross-sectional reduction rate becomes 50% or more. If the cross-sectional reduction rate is less than 50%, it is not preferable because there is a tendency that sufficient improvement in hardness by cold working cannot be obtained. On the other hand, there is no particular limitation on the upper limit of the cross-sectional reduction rate, but the cross-sectional reduction rate is preferably 99.99% or less, since processing tends to become difficult and further improvement in hardness cannot be expected. The final processing rate, which is the cross-sectional reduction rate when processing from the final heat treatment to the final wire diameter, is preferably 90% or more, more preferably 95% or more, and still more preferably 99% or more. This is because, in an Ag-Pd-Cu based alloy, hardness enhancement and reduction of volume resistivity are achieved by aging treatment, and the aging phenomenon is generally promoted as the final processing rate before aging treatment is higher.

[0049] Next, the heat treatment step is a step of heating and holding the alloy to be processed at an appropriate temperature to dissolve metal atoms in the alloy to be processed into the solid (form a solid solution), and then performing quenching without generating precipitates. As the conditions for this heat treatment, conventionally known conditions may be used. For example, after placing the alloy to be processed in a heat-resistant container and performing treatment at 600°C to 900°C for about 30 minutes to 3 hours in an inert gas atmosphere such as nitrogen or argon or a slightly reducing atmosphere, quenching may be performed directly as it is. The quenching method is not particularly limited, but a water cooling method, an oil cooling method, a cooling method using an inert gas, or the like can be used.

[0050] By repeatedly performing the above-described cold working and heat treatment on the ingot obtained in Step 1, an alloy wire rod before aging treatment having a wire diameter of 1.0 mm or less can be obtained.

[0051] [Step 3] Step 3 is a process to produce aged alloy wire for probe pins by performing an aging treatment on the pre-aged alloy wire obtained in Step 2 in an inert gas atmosphere or a slightly reducing atmosphere. Aging is the process by which mechanical properties such as hardness change over time, and aging treatment is a process that accelerates the time transformation by applying heat. In Step 3, the pre-aged alloy wire obtained in Step 2 is subjected to an aging treatment to precipitate PdCu ordered phase and intermetallic compounds of PdCu ordered phase and Zn in the matrix phase, thereby improving hardness. Conventional known conditions can be used for the aging treatment. For example, the pre-aged alloy wire obtained in Step 2 can be placed in a heat-resistant container and heat-treated at 300°C to 550°C for 1 minute to 20 hours in an inert gas atmosphere such as nitrogen or argon, and then allowed to cool naturally.

[0052] A second method for manufacturing the alloy wire for probe pins according to the present invention is the method for manufacturing the alloy wire for probe pins described above, comprising the following steps 1 to 3. Step 1: A metal material containing Ag, Pd, Cu, B, Zn, and Al is heated and melted to obtain an ingot containing 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.08 mass% to 0.17 mass% of B, 0.3 mass% to 1.3 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities. Step 2: The ingot obtained in Step 1 is subjected to repeated cold working and heat treatment with a cross-sectional reduction rate of 50% or more, to obtain an alloy wire before aging treatment with a final processing rate of 99% or more and a wire diameter of 0.1 mm or less. Step 3: The alloy wire before aging treatment obtained in Step 2 is subjected to aging treatment to obtain an aged alloy wire for probe pins.

[0053] By adopting this manufacturing method, it is possible to produce alloy wire for probe pins that not only meets the high hardness and processability required for probe pins, but also achieves 20 or more bending cycles at a final processing rate of 99% or more.

[0054] [Other Processes] The method for manufacturing alloy wire for probe pins according to the present invention may include additional steps in addition to steps 1-3 described above, as long as it is sufficient to manufacture the alloy wire for probe pins described above. For example, it is preferable to cut off a predetermined amount from the surface of the ingot using a shaper between steps 1 and 2. This is because the oxide film on the surface of the ingot manufactured in step 1, and inclusions such as alumina and silica embedded in the surface of the ingot can be removed, thereby increasing the compositional purity of the ingot.

[0055] The embodiments of the present invention described above are one aspect of the present invention and can be modified as appropriate without departing from the spirit of the present invention. Furthermore, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

[0056] As Step 1, the following procedure was performed: A metal material containing Ag, Pd, Cu, B, Zn, and Al was placed in a carbon crucible and melted at 1300°C in an inert gas atmosphere. The molten metal material was then poured into a mold to obtain an ingot with the composition shown in Table 1 and a shape of 20 mm × 20 mm × 150 mm. In Table 1, the No. column indicates the example number, and the Ag, Pd, Cu, B, Zn, and Al columns indicate the composition (mass%) of each element. Composition values ​​marked with "*" indicate the maximum or minimum value in Table 1. In the compositional analysis of the ingot, Ag and Pd were measured using gravimetric analysis, B, Zn, and Al were measured using ICP, and the remainder was considered to be Cu. Furthermore, these compositions do not preclude the possibility of inclusion of unavoidable impurities that are embedded in the measurement accuracy.

[0057] Next, before step 2, the surface of the ingot obtained in step 1 was cut and removed to a thickness of 1 mm using a shaper. This removed the oxide film on the surface of the ingot obtained in step 1, as well as inclusions such as alumina and silica embedded in the ingot surface.

[0058] Next, in step 2, the ingot, whose surface was cut off to a thickness of 1 mm using a shaper, underwent the following process. Cold working was performed at room temperature (25°C) using a grooved roll mill and wire drawing machine to reduce the cross-sectional area by 50% or more, and heat treatment was performed by holding it in a nitrogen atmosphere at 800°C for 1 hour and then rapidly cooling. These processes were repeated to obtain alloy wires with the wire diameters shown in Table 1 before aging treatment. In Table 1, the "Workability" column indicates that the final work rate was 90% or more, the "Final Work Rate" column shows the final work rate (%), and the "Wire Diameter" column shows the wire diameter (mm) after final processing. The "φ" in the "Wire Diameter" column indicates that the cross-section of the processed alloy wire is circular.

[0059] Next, in step 3, the alloy wire obtained in step 2 before aging treatment was subjected to an aging treatment by holding it for 1 hour in a slightly reducing atmosphere at 300-550°C with a mixture of 95% nitrogen and 5% hydrogen, thereby obtaining the alloy wire of the example. Comparative Example

[0060] As Step 1, the following procedure was performed: A metal material containing Ag, Pd, Cu, B, Zn, and Al was placed in a carbon crucible and melted at 1300°C in an inert gas atmosphere. The molten metal material was then poured into a mold to obtain an ingot with the composition shown in Table 2 and a shape of 20 mm × 20 mm × 150 mm. In Table 2, the No. column is the comparative example number, and the columns for Ag, Pd, Cu, B, Zn, and Al show the composition (mass%) of each element. In the compositional analysis of the ingot, Ag and Pd were measured using gravimetric analysis, B, Zn, and Al were measured using ICP, and the remainder was considered to be Cu. Furthermore, these compositions do not preclude the possibility of inclusion of unavoidable impurities that are embedded in the measurement accuracy.

[0061] The subsequent steps were carried out in the same manner as in the example to obtain the comparative alloy wire. In Table 2, the "Processability" column indicates that a final processing rate of 90% or more was Good, and a final processing rate of less than 90% was Bad. Those with a final processing rate of less than 90% had poor processability and could not be processed to a wire diameter of 1.0 mm or less. The "Final Processing Rate" column shows the final processing rate (%), and the "Wire Diameter" column shows the wire diameter (mm) after final processing. In the "Wire Diameter" column, "φ" indicates that the cross-section of the processed alloy wire is circular, and "□" indicates that the cross-section of the processed alloy wire is not circular.

[0062] [Evaluation] For alloy wires of each composition in the examples and comparative examples, Vickers hardness (HV), volume resistivity (μΩ・cm), and number of 90° bends were measured. The measurement results are shown in Tables 1 and 2, respectively. In Tables 1 and 2, the hardness column shows Vickers hardness (HV), the volume resistivity column shows volume resistivity (μΩ・cm), and the number of bends column shows the number of 90° bends. Furthermore, for samples with poor processability, it was not possible to process them into wires with a circular cross-section, so Vickers hardness (HV), volume resistivity (μΩ・cm), and number of 90° bends were not measured.

[0063]

[0064]

[0065] Table 1 shows that all alloy wires obtained using alloys within the composition range specified in this invention had a Vickers hardness of 490 HV to 600 HV and a volume resistivity of 11.5 μΩ·cm or less. Table 2 shows that those with a final processing rate of less than 90% had poor workability and could not be processed to a wire diameter of 1.0 mm or less. Furthermore, even those that could be processed to a wire diameter of 1.0 mm or less had a Vickers hardness of less than 490 HV.

[0066] [Composition Examples Focusing on Characteristics] Furthermore, compositions that satisfy a lower volume resistivity (7.80 μΩ·cm or less) are extracted from Table 1 and shown in Table 3. Focusing on B, a volume resistivity of 7.80 μΩ·cm is obtained when B is between 0.05 mass% and 0.09 mass%. Composition values ​​marked with "*" indicate the maximum or minimum value of B in Table 3.

[0067]

[0068] Furthermore, Table 4 shows compositions that satisfy higher hardness (530 HV or higher), extracted from Table 1. Focusing on B, a hardness of 530 HV or higher is obtained when B is between 0.11 mass% and 0.16 mass%. Composition values ​​marked with "*" indicate the maximum or minimum value of B in Table 4.

[0069]

[0070] Furthermore, Table 5 shows compositions that achieve a good balance between volume resistivity (8.50 μΩ·cm or less) and hardness (500 HV or more), extracted from Table 1. Focusing on B and Zn, when B is between 0.09 mass% and 0.16 mass% and Zn is between 1.0 mass% and 1.5 mass%, a volume resistivity of 8.50 μΩ·cm or less and a hardness of 500 HV or more are obtained. Composition values ​​marked with "*" indicate the maximum or minimum values ​​of B and Zn in Table 5.

[0071]

[0072] Furthermore, Table 6 shows compositions that satisfy the following conditions: a final wire diameter of 0.1 mm, a final processing rate of 99% or more, and 20 or more 90° bends, extracted from Table 1. Focusing on B and Zn, a 90° bend count of 20 or more is obtained when B is between 0.08 mass% and 0.17 mass% and Zn is between 0.3 mass% and 1.3 mass%. Composition values ​​marked with "*" indicate the maximum or minimum value in Table 6.

[0073]

[0074] The alloy according to the present invention achieves both the high hardness required for probe pins and processability into alloy wire, making it suitable for use as alloy wire for electrical testing probes or as alloy wire for probe pins obtained using alloy wire. Furthermore, the method for manufacturing the alloy wire for probe pins according to the present invention is suitable as a method for manufacturing the alloy wire for probe pins according to the present invention.

Claims

1. An alloy characterized by comprising 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.05 mass% to 0.17 mass% of B, 0.3 mass% to 1.5 mass% of Zn, 0.006 mass% to 0.10 mass% of Al, and the remainder being unavoidable impurities.

2. The alloy according to claim 1, wherein B is 0.05 mass% or more and 0.09 mass% or less.

3. The alloy according to claim 1, wherein B is 0.11 mass% or more and 0.16 mass% or less.

4. The alloy according to claim 1, wherein B is 0.09 mass% or more and 0.16 mass% or less, and Zn is 1.0 mass% or more and 1.5 mass% or less.

5. An alloy characterized by comprising 5.0 mass% to 15.0 mass% Ag, 48.2 mass% to 58.3 mass% Pd, 34.6 mass% to 42.3 mass% Cu, 0.08 mass% to 0.17 mass% B, 0.3 mass% to 1.3 mass% Zn, 0.006 mass% to 0.10 mass% Al, and the remainder being unavoidable impurities.

6. An alloy wire characterized by being obtained using the alloy described in claim 1.

7. The alloy wire material according to claim 6, wherein the wire diameter is 1.0 mm or less.

8. The alloy wire according to claim 6, wherein the Vickers hardness is 490 HV or more and 600 HV or less.

9. The alloy wire according to claim 6, wherein the volume resistivity is 11.5 μΩ·cm or less.

10. Alloy wire for probe pins, characterized by being obtained using the alloy wire described in claims 6 to 9.

11. An alloy wire obtained using the alloy described in claim 5, characterized in that the wire diameter is 0.1 mm or less.

12. A method for manufacturing alloy wire for probe pins, characterized by comprising the following steps 1 to 3: Step 1: A metal material containing Ag, Pd, Cu, B, Zn, and Al is heated and melted to obtain an ingot containing 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.05 mass% to 0.17 mass% of B, 0.3 mass% to 1.5 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities. Step 2: The ingot is repeatedly subjected to cold working with a cross-sectional reduction rate of 50% or more, followed by heat treatment, to obtain an alloy wire with a wire diameter of 1.0 mm or less before aging treatment. Step 3: The alloy wire before aging treatment is subjected to aging treatment to obtain an aged alloy wire for probe pins.

13. A method for manufacturing alloy wire for probe pins, characterized by comprising the following steps 1 to 3. Step 1: A metal material containing Ag, Pd, Cu, B, Zn, and Al is heated and melted to obtain an ingot containing 5.0 mass% to 15.0 mass% of Ag, 48.2 mass% to 58.3 mass% of Pd, 34.6 mass% to 42.3 mass% of Cu, 0.08 mass% to 0.17 mass% of B, 0.3 mass% to 1.3 mass% of Zn, and 0.006 mass% to 0.10 mass% of Al, with the remainder being unavoidable impurities. Step 2: The ingot is repeatedly subjected to cold working with a cross-sectional reduction rate of 50% or more, and heat treatment to obtain an alloy wire with a wire diameter of 0.1 mm or less before aging treatment. Step 3: The alloy wire before aging treatment is subjected to aging treatment to obtain an aged alloy wire for probe pins.

Images