Molybdenum-containing palladium-nickel alloy film, production method thereof, and molybdenum-containing palladium-nickel alloy plating solution

Abstract

To provide a palladium-nickel alloy film with low resistance and high hardness.SOLUTION: Provided are as follows: a palladium-nickel alloy film containing molybdenum of 0.5 wt.% or more and 7 wt.% or less; a probe pin including the palladium-nickel alloy film containing molybdenum of 0.5 wt.% or more and 7 wt.% or less; and a production method of the palladium-nickel alloy film containing molybdenum of 0.5 wt.% or more and 7 wt.% or less by electrolytic plating.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a molybdenum-containing palladium-nickel alloy film, a method for producing the same, and a molybdenum-containing palladium-nickel alloy plating solution.

Background Art

[0002] Currently, semiconductor substrates are used in many electronic devices, and contact probes are used for conduction inspection in the manufacturing quality control of semiconductor substrates. In recent years, MEMS (Micro-Electro-Mechanical-System) contact probes suitable for conduction inspection of narrow pitch bumps have been adopted. Since the contact probe makes contact with the semiconductor substrate to perform a conduction inspection, its tip portion (also referred to as a probe pin) is required to have a low contact resistance. Also, it is required to have high hardness in order to improve durability.

[0003] Regarding probes for current-carrying tests, Patent Document 1 discloses a probe having a needle main body portion formed of nickel or a nickel alloy and a needle tip portion formed of rhodium having high hardness. Also, Patent Document 2 discloses a probe pin composed of a material mainly containing Ni and added with Fe, Cr, Cu, etc., having a small electrical resistance and a metal surface that is difficult to be oxidized. Further, Patent Document 3 discloses a MEMS type probe including a plunger and a barrel having specific dimensions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a palladium-nickel alloy film is used as a constituent film such as a contact probe, characteristics of low contact resistance and high hardness are required. This disclosure has been made in view of such problems, and an object thereof is to provide a palladium-nickel alloy film having low contact resistance and high hardness.

Means for Solving the Problems

[0006] The gist of this disclosure is as follows. 1) A palladium-nickel alloy film containing 0.5 wt% or more and 7 wt% or less of molybdenum. 2) The palladium-nickel alloy film according to 1) above, having a contact resistance of 10 mΩ or less. 3) The palladium-nickel alloy film according to 1) or 2) above, having a Vickers hardness of 500 Hv or more. 4) The palladium-nickel alloy film according to any one of 1) to 3) above, having a specific resistance of 50 μΩ·cm or less. 5) The palladium-nickel alloy film according to any one of 1) to 4) above, having a contact resistance of 10 mΩ or less after heating in air at 400 °C for 10 seconds. 6) The palladium-nickel alloy film according to any one of 1) to 5) above, having a Vickers hardness of 700 Hv or more after heating in air at 400 °C for 10 seconds. 7) The palladium-nickel alloy film according to any one of 1) to 6) above, having a specific resistance of 35 μΩ·cm or less after heating in air at 400 °C for 10 seconds. 8) The palladium-nickel alloy film according to any one of 1) to 4) above, having a contact resistance of 15 mΩ or less after heating in air at 250 °C for 5 minutes. 9) The palladium-nickel alloy film according to any one of 1) to 5) above, having a Vickers hardness of 650 Hv or more after heating in air at 250 °C for 5 minutes. 10) The palladium-nickel alloy film according to any one of 1) to 6) above, having a specific resistance of 50 μΩ·cm or less after heating in air at 250°C for 5 minutes. 11) The palladium-nickel alloy film according to any one of 1) to 10) above, having a film thickness of 15 μm or more. 12) A probe pin including the palladium-nickel alloy film according to any one of 1) to 11) above. 13) A palladium-nickel alloy plating solution containing a nickel salt, a palladium salt, and a molybdenum salt. 14) A method for producing a palladium-nickel alloy film, comprising forming a palladium-nickel alloy film by electrolytic plating using the palladium-nickel alloy plating solution according to 13) above.

Advantages of the Invention

[0007] According to the present disclosure, a palladium-nickel alloy film with low contact resistance and high hardness can be provided.

Modes for Carrying Out the Invention

[0008] Hereinafter, specific embodiments of the present disclosure will be described with examples. However, each configuration and their combinations in each embodiment are merely examples, and within the scope not departing from the gist of the present disclosure, addition, omission, substitution, and other changes of the configuration are possible as appropriate. The present disclosure is not limited by the embodiments, and each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0009] The first embodiment of the present disclosure is a palladium-nickel alloy film containing 0.5 wt% or more and 7 wt% or less of molybdenum. The palladium-nickel alloy film according to this embodiment can achieve low contact resistance and high hardness. Even when a thermal load is applied, low contact resistance and high hardness can be maintained.

[0010] Adding different elements is one way to increase the hardness of plating films. However, these elements can form oxides, which can increase contact resistance and resistivity. In this regard, molybdenum has a resistivity of 5.2 x 10 -6 Ω·cm, and the resistivity of its oxide (MoO2) is 8.8×10 -5 Since the resistance is about Ω·cm, it is By depositing molybdenum, it is possible to form a plating film that combines high hardness and low resistance. If the molybdenum content is less than 0.5 wt%, the hardness does not increase, especially after heating. On the other hand, if the molybdenum content exceeds 7 wt%, the alloy film becomes black and brittle. A more preferable lower limit of the molybdenum content is 0.8 wt% or more, and particularly preferably 1 wt% or more. On the other hand, a more preferable upper limit of the molybdenum content is 5 wt% or less, and particularly preferably 3 wt% or less.

[0011] The palladium-nickel alloy coating according to this embodiment preferably has a contact resistance of 10 mΩ or less. A contact resistance of 10 mΩ or less can improve the performance of the coating as a contact member for contact probes, connectors, lead frames, and the like. A contact resistance of 8 mΩ or less is more preferable, and 6 mΩ or less is even more preferable. In this application, when simply referring to contact resistance, it means the contact resistance of the coating after deposition without heating.

[0012] The palladium-nickel alloy coating according to this embodiment preferably has a Vickers hardness of 500 Hv or more. A Vickers hardness of 500 Hv or more can improve the performance of the coating as a coating for contact members such as contact probes, connectors, and lead frames. In this application, when the term "Vickers hardness" is used simply, it refers to the Vickers hardness of the coating after deposition without heating.

[0013] The palladium-nickel alloy film according to this embodiment preferably has a specific resistance of 50 μΩ·cm or less. When the specific resistance is 50 μΩ·cm or less, the performance of the film can be improved as a film for contact members such as contact probes, connectors, and lead frames. More preferably, it is 40 μΩ·cm or less, and even more preferably, it is 35 μΩ·cm or less. In the present application, when simply referring to Vickers hardness, it means the Vickers hardness of the film without heating after film formation.

[0014] The palladium-nickel alloy film according to this embodiment preferably has a contact resistance of 10 mΩ or less after heating in air at 400°C for 10 seconds. In contact members such as contact probes, connectors, and lead frames, a heat load is applied due to frictional heat and Joule heat due to electrical resistance. However, when the contact resistance after heating is 10 mΩ or less, the performance of the film can be improved as a film for those contact members.

[0015] The palladium-nickel alloy film according to this embodiment preferably has a Vickers hardness of 700 Hv or more after heating in air at 400°C for 10 seconds. In contact members such as contact probes, connectors, and lead frames, a heat load is applied due to frictional heat and Joule heat due to electrical resistance. However, when the Vickers hardness after heating is 700 Hv or more, the performance of the film can be improved as a film for those contact members.

[0016] The palladium-nickel alloy film according to this embodiment preferably has a specific resistance of 35 μΩ·cm or less after heating in air at 400°C for 10 seconds. In contact members such as contact probes, connectors, and lead frames, a heat load is applied due to frictional heat and Joule heat due to electrical resistance. However, when the specific resistance after heating is 35 μΩ·cm or less, the performance of the film can be improved as a film for those contact members.

[0017] In addition, the palladium-nickel alloy film according to the present embodiment preferably has a contact resistance of 15 mΩ or less after being heated in air at 250°C for 5 minutes. In contact members such as contact probes, connectors, and lead frames, a heat load is applied due to frictional heat and Joule heat due to electrical resistance. However, if the contact resistance after heating is 15 mΩ or less, the performance of these contact members can be improved as the film thereof.

[0018] In addition, the palladium-nickel alloy film according to the present embodiment preferably has a Vickers hardness of 650 Hv or more after being heated in air at 250°C for 5 minutes. In contact members such as contact probes, connectors, and lead frames, a heat load is applied due to frictional heat and Joule heat due to electrical resistance. However, if the Vickers hardness after heating is 650 Hv or more, the performance of these contact members can be improved as the film thereof.

[0019] In addition, the palladium-nickel alloy film according to the present embodiment preferably has a specific resistance of 50 μΩ·cm or less after being heated in air at 250°C for 5 minutes. In contact members such as contact probes, connectors, and lead frames, a heat load is applied due to frictional heat and Joule heat due to electrical resistance. However, if the specific resistance after heating is 50 μΩ·cm or less, the performance of these contact members can be improved as the film thereof.

[0020] Note that the heat load of the palladium-nickel alloy film according to the present embodiment varies depending on the product form, specifications, etc. of probe pins, etc. Naturally, it can also be used at temperatures other than 400°C or 250°C described above. The palladium-nickel alloy film according to the present embodiment has an excellent effect that it can satisfy the above-described conditions even when heated in air at at least 400°C for 10 seconds or at 250°C for 5 minutes. The heat load of the palladium-nickel alloy film according to the present embodiment varies depending on the product form, specifications, etc. of probe pins, etc. Naturally, it can also be used at temperatures other than 400°C or 250°C described above. The palladium-nickel alloy film according to the present embodiment has an excellent effect that it can satisfy the above-described conditions even when heated in air at at least 400°C for 10 seconds or at 250°C for 5 minutes.

[0021] Although it is technically difficult to form a palladium-nickel alloy film with a thickness of a certain level or more by plating, according to this embodiment, a palladium-nickel alloy film with a thickness of 15 μm or more can be formed. When the film thickness is 15 μm or more, it can be used for electroforming. Also, as a film for contact members such as contact probes, plungers, connectors, and lead frames, its performance can be improved. More preferably, it is 18 μm or more, and even more preferably, it is 20 μm or more. In the present disclosure, the film thickness means the film thickness of a film without obvious cracks.

[0022] In the palladium-nickel alloy film according to this embodiment, the nickel content is preferably 10 wt% or more and 50 wt% or less. The nickel content affects the appearance of the plating film, the internal stress of the film, and the hardness. This is because when it is less than 10 wt%, the stress of the film increases, while when it exceeds 50 wt%, the corrosion resistance decreases.

[0023] The second embodiment is a probe pin including the palladium-nickel alloy film according to one embodiment. The probe pin constitutes the tip portion of the contact probe and is also referred to as a plunger. The contact probe is a conduction inspection device for electronic components, semiconductor substrates, printed mounting substrates, etc. The probe pin according to the second embodiment has the palladium-nickel alloy film according to the first embodiment formed on a substrate such as copper or a copper alloy, iron or an iron alloy, silver or a silver alloy.

[0024] The manufacturing method of the palladium-nickel alloy film according to the first embodiment will be specifically shown below. The palladium-nickel alloy film according to this embodiment is formed by electrolytic plating. The plating bath contains palladium salt, nickel salt, and molybdenum salt shown below, and if necessary, a stress reliever, a conductive salt (pH buffer), a brightener, etc. may be added.

[0025] (Palladium salt) As palladium salts, tetraamminepalladium(II) chloride, dibromotetraamminepalladium ([Pd(NH3)4]Br2), diiodotetraamminepalladium ([Pd(NH3)4]I2), tetraamminepalladium sulfate ([Pd(NH3]4)(SO4)), and other tetraamminepalladium compounds; dichlorodiamminepalladium ([Pd(NH3)2Cl2]), dibromodiamminepalladium ([Pd(NH3)2Br2]), diiododiamminepalladium ([Pd(NH3)2I2]), diamminepalladium sulfate ([Pd(NH3)2(SO4)]), and other diamminepalladium compounds can be used.

[0026] (Nickel salt) As nickel salts, nickel(II) sulfate hydrate, nickel acetate, nickel amidosulfate, nickel chloride, etc. can be used, and the acid radical of the nickel salt is not limited.

[0027] (Molybdenum salt) As molybdenum salts, molybdenum compounds such as molybdic acid, potassium molybdate, calcium molybdate, barium molybdate, disodium molybdate(IV) dihydrate, ammonium molybdate(IV) tetrahydrate, sodium phosphomolybdate n-hydrate, 12-molybdophosphoric acid n-hydrate, and thiomolybdic acid can be used.

[0028] The ratios of molybdenum, nickel, and palladium in the film can be changed by the concentration ratios of the respective salts in the plating bath. However, since molybdenum salts not only control the molybdenum ratio but also affect the appearance and internal stress of the film, it is necessary to determine the concentration in consideration of this point. The preferred concentrations of each metal species in the plating solution can be as follows. · Molybdenum salt: 0.1 - 3.0 g / L · Nickel salt: 2.0 - 15.0 g / L · Palladium salt: 2.0 - 15.0 g / L

[0029] (Stress reliever) As stress relaxants, naphthalenesulfonic acids, aromatic sulfonamides, aromatic carboxylic acids, etc. are added. For example, saccharin, sodium benzenesulfonate, sodium chromotropate, benzoic acid, etc. can be mentioned. In particular, it is preferable to use sodium benzenesulfonate, sodium chromotropate, and benzoic acid. The addition of the stress relaxant is optional, but when adding, it can be 10 to 50 g / L.

[0030] (Conductive salt, pH buffer) Since the type of conductive salt may affect the film appearance and internal stress, it is necessary to select it while considering the desired properties. Also, the conductive salt may function as a pH buffer, and when added for such a purpose, it is called a pH buffer. As the pH buffer, those having a buffering action near the generally used pH can be selected. As the conductive salt (pH buffer), in addition to ammonium sulfate, ammonium chloride, ammonium amidosulfate, ammonium citrate, etc. can be used. The addition of the conductive salt and / or pH buffer is optional, but when adding, 15 to 100 g / L can be added respectively.

[0031] (Brightening agent) As the brightening agent, a cyclic compound having a hydrophilic substituent, or a heterocyclic compound containing an electron-withdrawing heteroatom, or a mixture thereof can be added. For example, benzoic acid, benzenesulfonamide, benzamide, nicotinic acid, nicotinamide, isonicotinamide, pyridinesulfonic acid, pyridinesulfonamide, naphthalenetrisulfonic acid, coumarin, etc. can be mentioned. By adding the brightening agent, gloss can be obtained on the film. The addition of the brightening agent is optional, but when adding, 0.1 to 20.0 g / L can be added.

[0032] The electrolytic plating conditions can be as follows. By this, the molybdenum concentration in the plating film can be adjusted to an appropriate value. However, the following conditions are only examples, and the present invention is not limited to these conditions. For conditions that do not affect the molybdenum concentration (such as the bath volume, the material of the anode, the material of the cathode, etc.), they can be appropriately selected from known conditions and materials. (Electrolytic plating conditions) Cathode current density: 1.0~4.0 A / dm 2 pH: 6.0~9.5 Bath temperature: 30~50 °C Stirring speed: 100~500 rpm Palladium salt: 2~15 g / L Nickel salt: 2~15 g / L Molybdenum salt: 0.1~3.0 g / L

Examples

[0033] Next, the examples and comparative examples of the present invention will be described. Note that the following examples are merely representative examples, and the present invention need not be limited to these examples and should be interpreted within the scope of the technical idea described in the specification.

[0034] The method for evaluating the characteristics of the palladium-nickel alloy film is shown below. (Measurement of film thickness and film composition) The measurement of the film thickness and film composition was performed using a fluorescence X-ray film thickness meter FT-160h manufactured by Hitachi High-Tech Corporation. The central part of the sample was measured with a measurement diameter of 0.1 mm, a tube voltage of 45 kV, a tube current of 1000 μA, using Al1000 as the primary filter, and the measurement was carried out under the conditions of the thin film FP method.

[0035] (Observation of film appearance) The observation of the film appearance was carried out using a digital microscope VHX-8000 manufactured by Keyence Corporation. The film surface was observed at 2000 times magnification to confirm that there were no cracks in the film.

[0036] (Measurement of contact resistance) The contact resistance was measured five times using an electric contact simulator CRS-113-AU type (Au wire, φ0.5 mm) manufactured by Yamazaki Seiki Kenkyusho Co., Ltd. The average value of the results at each measurement point was calculated under the conditions of applying a load of 0.1 N to the central part of the sample, an operating load of 1 mm, an operating speed of 1 mm / min, a range of 20 mΩ, and 600-point measurement.

[0037] (Measurement of Vickers hardness) The Vickers hardness was measured five times at the central part of the sample using a microhardness tester HM-221 manufactured by Mitutoyo Corporation with a Vickers indenter, and the average value was calculated. The measurement conditions were a load time of 4 seconds, a holding time of 10 seconds, an unloading time of 4 seconds, and an approach speed of 3 seconds. Note that for the hardness measurement of the film, since a load is applied to the indenter to form an indentation on the film and the hardness is calculated from the diagonal line of this indentation, when the film thickness is thin, the indenter reaches the base material. Also, if the load is too small, the variation in the diagonal line of the indentation becomes large and the lower limit of quantification cannot be exceeded. Thus, when the film thickness is thin, the hardness was not measured because the reliability of the measured hardness value is low.

[0038] (Measurement of specific resistance) The specific resistance was measured using a resistivity meter Loresta-GX (MCP-T700) manufactured by Nitto Seiko Analytic Co., Ltd. by the four-terminal four-probe method. A SUS304 plate of 2 cm × 2.5 cm was used as the base material, and after plating, the film was peeled off from the base material to prepare a plating foil. This plating foil was processed to be 1 cm × 1 cm, and the specific resistance was measured.

[0039] (Regarding the plating bath) The specific components of the plating baths used in the examples and comparative examples are shown below. Palladium salt: Tetraamminepalladium(II) chloride Nickel salt: Nickel(II) sulfate hexahydrate Molybdenum salt: Sodium molybdate dihydrate Others: pH buffer, conductive salt, brightener

[0040] (Example 1: Measurement of contact resistance) A palladium-nickel plating bath composed of the components described in Table 1 was prepared, and using this bath, electrolytic plating was carried out under the conditions described in Table 2 to form a palladium-nickel alloy film. At this time, the substrate was a copper plate of 2 cm × 2.5 cm. The thickness of the obtained palladium-nickel alloy film (Mo: 2.1 wt%, Ni: 24.3 wt%, Pd: 73.6 wt%) was 22.7 μm, and the contact resistance was 4.2 mΩ. Next, the alloy film was heated on a digital hot plate HP-1SA (manufactured by Matsuura Seisakusho Co., Ltd.) in the atmosphere at 400 °C for 10 seconds. During heating, the temperature was set so that the surface of the hot plate reached 400 °C, and the surface temperature was measured with a digital thermometer TX1002 (manufactured by Yokogawa Electric Corporation). The contact resistance of the palladium-nickel alloy film after heating was 6.0 mΩ.

[0041] (Example 2: Measurement of Vickers hardness) Since it is difficult to measure both the contact resistance and the Vickers hardness on the same sample, different samples were prepared. As will be described later, although the film composition and film thickness are slightly different between Example 1 and Example 2, since plating was carried out under the same electrolysis conditions using a plating solution of the same composition, it can be said that they are practically the same sample. The thickness of the obtained palladium-nickel alloy film (Mo: 2.7 wt%, Ni: 30.5 wt%, Pd: 66.8 wt%) was 19.6 μm, and the Vickers hardness Hv was 538.0 Hv. Next, the alloy film was heated in the atmosphere at 400 °C for 10 seconds using a digital hot plate HP-1SA (manufactured by Matsuura Seisakusho Co., Ltd.). During heating, the temperature was set so that the surface of the hot plate reached 400 °C, and the surface temperature was measured with a digital thermometer TX1002 (manufactured by Yokogawa Electric Corporation). The Vickers hardness of the alloy film after heating was 790.0 Hv. As can be seen from the results of Example 1 and this Example 2 described above, it was successfully achieved to increase the hardness while suppressing the increase in contact resistance.

[0042] (Example 3: Measurement of specific resistance) Since the specific resistance cannot be measured with the substrate attached, it is necessary to remove the plating film from the substrate before measurement. Therefore, as a substrate from which the plating film can be easily removed, a SUS304 plate (2 cm × 2.5 cm) was used, and a palladium-nickel plating solution composed of the components described in Table 1 was prepared in the same manner as in Example 1, and electrolytic plating was performed under the conditions described in Table 2. The thickness of the obtained palladium-nickel alloy film (Mo: 2.1 wt%, Ni: 24.2 wt%, Pd: 73.6 wt%) was 22.7 μm, and the specific resistance was 32.8 μΩ. Next, the alloy film was heated in the air at 400 °C for 10 seconds using a digital hot plate HP-1SA (manufactured by Matsuura Seisakusho Co., Ltd.). During heating, the temperature was set so that the surface of the hot plate reached 400 °C, and the surface temperature was measured with a digital thermometer TX1002 (manufactured by Yokogawa Electric Corporation). The specific resistance of the alloy film after heating was 32.6 μΩ. As can be seen from this result, the increase in specific resistance was suppressed even after heating.

[0043]

Table 1

[0044]

Table 2

[0045] (Comparative Example 1: Without adding molybdenum) A palladium-nickel plating bath composed of the components described in Table 3 was prepared, and electrolytic plating was performed under the same electrolysis conditions (Table 2) as in Example 1 to form a palladium-nickel alloy film (Ni: 26.7 wt%, Pd: 73.3 wt%). A copper plate (2 cm × 2.5 cm) was used as the substrate. The thickness of the alloy film after film formation was 25.7 μm. Next, as in Example 1, it was heated in the air at 400 °C for 10 seconds, and the Vickers hardness was measured. The Vickers hardness of the alloy film after heating was 638.3 Hv, and a film with as high a hardness as that of Example 2 could not be obtained.

[0046]

Table 3

[0047] The summary of the above results is shown in Table 4.

Table 4

[0048] (Example 4: Measurement of Contact Resistance) In Example 4, the plating solution composition and electrolysis conditions were changed from those in Examples 1 to 3. A palladium-nickel plating bath composed of the components described in Table 5 was prepared, and using this, electrolytic plating was performed under the conditions described in Table 6 to form a palladium-nickel alloy film. At this time, the substrate was a copper plate of 2 cm × 2.5 cm. The film thickness of the obtained palladium-nickel alloy film (Mo: 1.5 wt%, Ni: 26.9 wt%, Pd: 71.6 wt%) was 17.2 μm, and the contact resistance was 3.4 mΩ. Next, the alloy film was heated in the air at 250 °C for 5 minutes using a digital hot plate HP-1SA (manufactured by Matsuura Seisakusho Co., Ltd.). During heating, the temperature was set so that the surface of the hot plate reached 250 °C, and the surface temperature was measured with a digital thermometer TX1002 (manufactured by Yokogawa Electric Corporation). The contact resistance of the palladium-nickel alloy film after heating was 10.8 mΩ.

[0049] (Example 5: Measurement of Vickers Hardness) Since it is difficult to measure both the contact resistance and the Vickers hardness on the same sample, different samples were prepared. As will be described later, although the film composition and film thickness are slightly different between Example 4 and Example 5, since plating was performed under the same electrolysis conditions using a plating solution of the same composition, it can be said that they are practically the same sample. The film thickness of the obtained palladium-nickel alloy film (Mo: 2.3 wt%, Ni: 31.6 wt%, Pd: 66.1 wt%) was 19.6 μm, and the Vickers hardness Hv was 587.7 Hv. Next, the alloy film was heated in air at 250°C for 5 minutes using a digital hot plate HP-1SA (manufactured by Matsuura Manufacturing Co., Ltd.). During heating, the temperature was set so that the surface of the hot plate reached 250°C, and the surface temperature was measured with a digital thermometer TX1002 (manufactured by Yokogawa Electric Corporation). The alloy film after heating had a Vickers hardness of 659.9 Hv. As can be seen from the results of Example 4 and this Example 5, we succeeded in increasing the hardness while suppressing the increase in contact resistance.

[0050] (Example 6: Measurement of Specific Resistance) Since the specific resistance cannot be measured with the substrate attached, it is necessary to peel off the plating film from the substrate before measurement. Therefore, as a substrate from which the plating film can be easily peeled off, a SUS304 plate (2 cm × 2.5 cm) was used, and a palladium-nickel plating solution composed of the components described in Table 5 was prepared in the same manner as in Example 4, and electrolytic plating was performed under the conditions described in Table 6. The obtained palladium-nickel alloy film (Mo: 1.9 wt%, Ni: 28.4 wt%, Pd: 69.7 wt%) had a film thickness of 9.9 μm and a specific resistance of 42.3 Ω. In Example 6, when measuring the specific resistance of the film, a thickness of 15 μm or more is not required, so the electrolysis time was shortened to make the film thickness approximately 10 μm. As described above, since Example 6 performs electrolytic plating with the same composition plating solution as in Example 4, it is possible to make the film thickness 15 μm or more by extending the electrolysis time. Next, the alloy film was heated in air at 250°C for 5 minutes using a digital hot plate HP-1SA (manufactured by Matsuura Manufacturing Co., Ltd.). During heating, the temperature was set so that the surface of the hot plate reached 250°C, and the surface temperature was measured with a digital thermometer TX1002 (manufactured by Yokogawa Electric Corporation). The alloy film after heating had a specific resistance of 41.9 μΩ. As can be seen from this result, the increase in specific resistance was suppressed even after heating.

[0051]

Table 5

[0052]

Table 6

[0053] (Comparative Example 2: Without adding molybdenum) In Comparative Example 2, the plating solution composition and electrolysis conditions were changed from those of Comparative Example 1. A palladium-nickel-ruthenium plating bath composed of the components described in Table 7 was prepared, and electrolytic plating was performed under the same electrolysis conditions (Table 6) as in Example 4 to form a palladium-nickel alloy film (Ni: 25.4 wt%, Pd: 74.6 wt%). A copper plate (2 cm × 2.5 cm) was used as the substrate. The thickness of the alloy film after film formation was 18.6 μm. Next, in the same manner as in Example 4, it was heated in the atmosphere at 250°C for 5 minutes, and the Vickers hardness was measured. The Vickers hardness of the alloy film after heating was 618.7 Hv, and a film with as high a hardness as that of Example 4 could not be obtained.

[0054]

Table 7

[0055] The summary of the above results is shown in Table 8.

Table 8

Industrial Applicability

[0056] The palladium-nickel alloy film according to the embodiment of the present disclosure is useful as a constituent film in lead frames, printed wiring boards, rigid substrates, flexible substrates, tape carriers, connectors, power devices, wires, probe pins, MEMS contact probes, and the like.

Claims

1. A palladium-nickel alloy film containing 0.5 wt% or more and 7 wt% or less of molybdenum.

2. The palladium-nickel alloy film according to Claim 1, having a contact resistance of 10 mΩ or less.

3. The palladium-nickel alloy film according to Claim 1, having a Vickers hardness of 500 Hv or more.

4. The palladium-nickel alloy film according to Claim 1, having a specific resistance of 50 μΩ·cm or less.

5. The palladium-nickel alloy film according to Claim 1, having a contact resistance of 10 mΩ or less after heating in air at 400°C for 10 seconds.

6. The palladium-nickel alloy film according to Claim 1, having a Vickers hardness of 700 Hv or more after heating in air at 400°C for 10 seconds.

7. The palladium-nickel alloy film according to Claim 1, having a specific resistance of 35 μΩ·cm or less after heating in air at 400°C for 10 seconds.

8. The palladium-nickel alloy film according to Claim 1, having a contact resistance of 15 mΩ or less after heating in air at 250°C for 5 minutes.

9. The palladium-nickel alloy film according to Claim 1, having a Vickers hardness of 650 Hv or more after heating in air at 250°C for 5 minutes.

10. The palladium-nickel alloy film according to Claim 1, having a specific resistance of 50 μΩ·cm or less after heating in air at 250°C for 5 minutes.

11. The palladium-nickel alloy film according to Claim 1, having a film thickness of 15 μm or more.

12. A probe pin including the palladium-nickel alloy film according to any one of Claims 1 to 11.

13. A palladium-nickel alloy plating solution containing a nickel salt, a palladium salt, and a molybdenum salt.

14. A method for manufacturing a palladium-nickel alloy film, comprising forming a palladium-nickel alloy film by electrolytic plating using the palladium-nickel alloy plating solution according to Claim 13.

Images