Wire for electrical characteristics testing and method for manufacturing the same

Abstract

The problem to be solved by the present invention is to provide a wire for testing electrical characteristics with high hardness and high conductivity. The wire for testing electrical characteristics that solves the above problem is made of a copper alloy, and has a fibrous structure extending in a direction at an angle of 0.5° to 20° relative to the longitudinal direction on the outer periphery.

Description

Technical Field

[0001] The invention relates to a wire for testing electrical characteristics and a manufacturing method thereof. Background Art

[0002] In recent years, with the miniaturization of electronic devices, various circuit substrates used in these devices require high-density mounting, etc. On the other hand, various circuit substrates such as various mounting substrates and IC packaging substrates are usually subjected to various electrical property tests such as DC resistance value measurement and conduction test during manufacturing. Such electrical property tests are usually often composed of a contact probe for contacting the electrodes of the circuit substrate and a test device (signal processing device) for measuring resistance values, etc. via the contact probe (for example, Patent Document 1). Furthermore, the wires used in such test devices or contact probes are also required to be reduced in diameter or have high conductivity according to the high-density mounting of various circuit substrates. In addition, the wires used in the test devices or contact probes are sometimes required to have high hardness.

[0003] As the conductor used in the above-mentioned test device and probe, copper alloy wire is generally used. Generally, the harder the copper alloy is, the harder it is. Therefore, the hardness of the copper alloy wire is increased by wire drawing or rolling.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2016 / 159316 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In order to improve the hardness by the above-mentioned wire drawing or rolling process, it is necessary to increase the casting diameter and repeat the wire drawing or rolling process multiple times. However, it is difficult to perform wire drawing on a wire with a large casting diameter, which easily leads to a decrease in productivity or an increase in production costs. Furthermore, the conductivity of general copper alloys is easily reduced due to wire drawing or rolling, and it is difficult to obtain a wire with both high hardness and high conductivity.

[0009] The main object of the present invention is to provide a wire for testing electrical characteristics having high hardness and high conductivity and a method for manufacturing the same.

[0010] Solutions to the problem

[0011] In order to solve the above-mentioned problems, according to one embodiment of the present invention, there is provided a wire for testing electrical characteristics, which is composed of a copper alloy containing 0.1 to 30 mass % of silver and the remainder being copper and inevitable impurities, wherein the wire for testing electrical characteristics is characterized in that:

[0012] The outer periphery has a fibrous structure extending in a direction forming an angle of 0.5° to 20° with respect to the longitudinal direction.

[0013] The Vickers hardness is 300 HV or more and the electrical conductivity is 57% IACS or more.

[0014] According to another aspect of the present invention, there is provided a method for manufacturing a wire for testing electrical characteristics, characterized by comprising:

[0015] A step of preparing a copper alloy wire containing 0.1 to 30 mass % of silver and the remainder being copper and inevitable impurities; and

[0016] The step of twisting the copper alloy wire by rotating the copper alloy wire in a circumferential direction of the copper alloy wire while conveying the copper alloy wire in one direction and pressing the copper alloy wire in a predetermined direction,

[0017] In the step of twisting the copper alloy wire, the angle between the pressed copper alloy wire and the conveying direction of the copper alloy wire is set to 10° to 70°, and the rotation speed in the circumferential direction relative to the conveying speed of the copper alloy wire is set to 1 to 60 rpm.

[0018] Effects of the Invention

[0019] According to the present invention, it is possible to provide a wire for testing electrical characteristics having high hardness and high electrical conductivity and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram for explaining a contact probe or a test device that can use a lead wire for electrical characteristics testing.

[0021] Figure 2 This is a schematic diagram for explaining a twisting process step in a method of manufacturing a lead wire for testing electrical characteristics.

[0022] Figure 3 This is a schematic diagram for explaining a twist recovery step in a method for producing a copper wire for an electrical characteristics test.

[0023] Figure 4 This is a graph showing the relationship between the angle formed by the length direction of the electrical characteristics test lead wire and the extending direction of the fibrous structure and the Vickers hardness with respect to the twisting amount.

[0024] Figure 5 This is a schematic diagram for explaining a twist recovery step in a method of manufacturing a lead wire for testing electrical characteristics. DETAILED DESCRIPTION

[0025] Next, a lead wire for testing electrical characteristics (hereinafter also simply referred to as a “lead wire”) and a method for manufacturing the same according to an embodiment of the present invention will be described.

[0026] However, the conductive wire and the method for producing the conductive wire of the present invention are not limited to the embodiments described below. In the present specification, when "to" indicates a numerical range, the upper limit and the lower limit are included in the numerical range.

[0027] [Electrical characteristics test lead wire]

[0028] The conductive wire of this embodiment is made of copper alloy.

[0029] The copper alloy preferably contains one or more of silver, tin, beryllium, zinc, nickel, magnesium, aluminum, titanium, zirconium, indium, silicon, and phosphorus, and the remainder is copper and inevitable impurities. The copper alloy wire is preferably a copper alloy containing copper and silver.

[0030] The amount of silver is appropriately selected depending on the desired properties of the wire, but is preferably 0.1 to 30% by mass, more preferably 10 to 15% by mass. When the amount of silver is within this range, the hardness and conductivity of the wire can be easily controlled within the desired range.

[0031] The diameter of the wire is appropriately selected according to the use of the wire, but is usually preferably 0.2 mm or less, more preferably 0.01 mm to 0.1 mm. If the diameter of the wire is within this range, the wire can be arranged at a narrow pitch when used in a wire electrical characteristics tester or a probe pin.

[0032] The guide wire of the present embodiment has a fibrous structure extending in a predetermined direction at its outer peripheral portion.

[0033] The "periphery of the wire" refers to an area close to the peripheral surface of the wire, for example, an area from the peripheral surface of the wire to a depth of 1 / 3 of the wire diameter. The angle formed by the length direction of the wire and the extension direction of the fibrous structure is 0.5° to 20°, preferably 0.5° to 11.2°, and more preferably 3.3° to 11.2°. The fibrous structure extending in the above direction indicates that a certain force is applied in a specified direction during its manufacture.

[0034] Specifically, when manufacturing the conductor, a fibrous structure extending in a certain direction is generated around the conductor by performing a twisting process described later. Furthermore, if the angle between the length direction of the conductor and the extension direction of the fibrous structure is 0.5° or more, not only the hardness of the conductor is significantly improved, but also the conductivity is likely to be improved. If the angle exceeds 20°, there is a possibility of wire breakage, and if it is less than 20°, the hardness and conductivity are likely to be improved. Whether the outer periphery of the conductor has the fibrous structure and the angle between the length direction of the conductor and the extension direction of the fibrous structure can be confirmed by grinding off about 20% of the diameter of the conductor from the surface of the conductor and observing the ground surface with a video microscope or a scanning electron microscope.

[0035] The electrical conductivity of the conductive wire is preferably 50% IACS or higher, more preferably 57% IACS or higher.

[0036] When the electrical conductivity of the conductive wire is 60% IACS or more, the conductive wire can be easily used for various purposes as described below. The upper limit of the electrical conductivity of the conductive wire is not particularly limited, but is generally about 85% IACS.

[0037] The Vickers hardness of the wire is appropriately selected depending on the application of the wire.

[0038] For example, when the conductor is used as a probe for electrical properties testing described later, its Vickers hardness is preferably 300 HV or more, more preferably 320 HV or more. On the other hand, when the conductor is used as a lead wire of a device for electrical properties testing described later, its Vickers hardness is preferably 250 HV or more. If the Vickers hardness is within the above range, it is easy to use for various purposes. The Vickers hardness in this specification refers to the value measured according to JIS Z 2244.

[0039] The elongation of the wire is preferably 1% to 5%.

[0040] The elongation can be determined using a precision universal testing machine (for example, manufactured by Shimadzu Corporation) etc. When the elongation of the wire is 5% or less, the end of the wire is unlikely to sag even if it repeatedly contacts other members.

[0041] The conductive wire preferably has high linearity.

[0042] The curvature radius of the wire is preferably 300 mm or more, more preferably 1000 mm or more. If the linearity of the wire is high, when the wire is used in an electrical property test device, etc., it is possible to prevent adjacent wires from contacting or tangling with each other. If the linearity of the wire is high, it is easy to use the wire for various purposes. The above-mentioned curvature radius is a value calculated by using a digital microscope VHX-6000 manufactured by KEYENCE Corporation to select any three points of the arc of the sample.

[0043] This wire is mainly used in devices and instruments for testing electrical characteristics.

[0044] Examples of uses of the lead wire include lead wires of an electrical characteristics test device and probe pins of a contact probe, but the use is not limited to these.

[0045] Figure 1 A contact probe 20 for testing electrical characteristics of a circuit substrate 10 having a substrate 11 and electrodes 12 and a part of a test device 30 connected thereto are shown.

[0046] Figure 1 The contact probe 20 shown has a probe 22 and a support portion 21 that supports the probe 22. The test device 30 has a lead 32, a holding portion 31 that supports the lead 32, and a signal processing portion (not shown) connected to the lead 32. In the contact probe 20 and the test device 30 of this structure, by abutting the probe 22 against the electrode 12 of the circuit substrate 10 and the lead 32, an electrical signal from the circuit substrate 10 side is transmitted to the test device 30. Furthermore, by detecting the electrical signal by the signal processing portion, the DC resistance value of the circuit substrate 10 can be measured and the conduction test can be performed.

[0047] It should be noted that the above-mentioned wire can be used for any one of the probe 22 of the contact probe 20 and the lead 32 of the test device 30. The probe 22 and the lead 32 are repeatedly in contact. Therefore, if the hardness of the wire used in these is low, it may be worn due to repeated contact. In contrast, the above-mentioned wire has both high hardness and high conductivity. Therefore, it is very useful in these applications.

[0048] It should be noted that when the above-mentioned wire is used as the lead 32, an insulating coating can also be formed around the above-mentioned wire. If an insulating coating is formed around the wire, it is possible to suppress contact between adjacent leads 32. The insulating coating can be a coating made of resin, similar to the insulating coating of a general wire. Examples of resins that can be used for the insulating coating include: polyurethane resin, nylon resin, polyester resin, epoxy resin, polyesterimide resin, polyamide resin, polyamideimide resin, etc. However, it is not limited to these. Its thickness is also appropriately selected according to the purpose, for example, it can be set to about 1.0μm to 10μm.

[0049] [Method for manufacturing lead wire for electrical characteristics testing]

[0050] The above-mentioned conductive wire can be manufactured, for example, by the following method. However, the manufacturing method of the above-mentioned conductive wire is not limited to this method. The manufacturing method of the present embodiment comprises: a step of preparing a copper alloy wire containing copper and silver (hereinafter also referred to as a "preparation step"); a step of conveying the copper alloy wire in one direction while pushing the copper alloy wire in a predetermined direction and rotating it in the circumferential direction of the copper alloy wire (hereinafter also referred to as a "twisting processing step"); and a step of restoring the twisted copper alloy wire (hereinafter also referred to as a "twisting restoration step").

[0051] In the preparation step, a copper alloy wire containing copper and silver is prepared. The composition of the copper alloy wire is set to be the same as the composition of the copper alloy contained in the above-mentioned conductive wire. The copper alloy wire can be a copper alloy wire manufactured by any method, for example, a copper alloy wire obtained by drawing a wire material produced by any casting diameter. The diameter of the prepared copper alloy wire is preferably 0.2 mm or less, and more preferably 0.01 mm to 0.1 mm.

[0052] The schematic diagram of the twisting process of this embodiment is as follows: Figure 2 shown.

[0053] In this twisting process, the copper alloy wire 130 prepared in the above-mentioned preparation process is twisted in the processing device 200 as described above.

[0054] The processing device 200 includes a pair of rotating plates (a first rotating plate 211a and a second rotating plate 211b) arranged opposite to each other with the copper alloy wire 130 interposed therebetween. The pair of rotating plates (the first rotating plate 211a and the second rotating plate 211b) are connected to a motor (not shown) and are configured to rotate integrally at a predetermined speed in the circumferential direction of the copper alloy wire 130 with the copper alloy wire 130 as the central axis.

[0055] One rotating plate (the first rotating plate 211a in this embodiment) has a first support portion 212a and a third support portion 212c for supporting the copper alloy wire 130 at a predetermined height. The other rotating plate (the second rotating plate 211b in this embodiment) has a second support portion 212b for pressing the copper alloy wire 130 to a predetermined position. The ends of each support portion 212a, 212b, 212c have grooves (not shown) for supporting the copper alloy wire 130.

[0056] In the twisting process, first, the copper alloy wire 130 is supported by the first support part 212a, the second support part 212b, and the third support part 212c of the processing device 200. At this time, the angle ( Figure 2The height or position of the first support part 212a, the second support part 212b, and the third support part 212c is adjusted so that the angles α and β in the conveying direction are 10° to 70°. The angles α and β formed by the copper alloy wire 130 and the conveying direction are preferably 20° to 50°, and more preferably 20° to 40°. The above-mentioned angles α and β may be different values, but are preferably the same value.

[0057] Next, while conveying the copper alloy wire 130 from one reel 100 side to the other reel 160 side at a certain speed, the rotating plate (first rotating plate 211a, second rotating plate 211b) of the processing device 200 is rotated at a certain speed in the circumferential direction of the copper alloy wire 130. At this time, the rotation speed of the rotating plate relative to the conveying speed, that is, the twisting processing amount defined by the following formula is 1 to 60 turns / mm, preferably 1 to 30 turns / mm, more preferably 1 to 20 turns / mm, and further preferably 1 to 15 turns / mm.

[0058] Twisting amount = rotation speed [rpm] / conveying speed of copper alloy wire 130 [mm / min]

[0059] By setting the twisting amount within the above range, an appropriate force is applied to the copper alloy wire 130 , and a fibrous structure is observed on the outer peripheral portion of the copper alloy wire 130 .

[0060] The schematic diagram of the torsion recovery process of this embodiment is as follows Figure 3 shown.

[0061] In the twist recovery step, the copper alloy wire 130 after the twisting step is twisted and recovered.

[0062] In the twist recovery step, the original winding reel 160 (supply reel) on which the copper alloy wire 130 after the twist processing step is wound is rotated, and the copper alloy wire 130 is wound by the recovery reel 170 to recover the twist of the copper alloy wire material 130. The supply reel 160 needs to be rotated in the direction opposite to the rotation direction of the rotating plates (first rotating plate 211a, second rotating plate 211b) of the processing device 200. The twist recovery amount of the copper alloy wire 130 is defined by the following formula.

[0063] Torsion recovery

[0064] = Number of revolutions of the supply reel [rpm] / conveying speed of the copper alloy wire 130 [mm / min]

[0065] Specifically, in the twist recovery step, the twist recovery amount is smaller than the twist processing amount, and is set to about 0.02 to 3.0% of the twist processing amount. The twist recovery step of the copper alloy wire 130 mainly contributes to improving the handleability of the copper alloy wire.

[0066] In addition, the above-mentioned twisting process and twist recovery process are usually performed at room temperature.

[0067] [Example]

[0068] The present invention is described in more detail below by way of examples, but the scope of the present invention is not limited by these examples, and the embodiments can be modified without departing from the gist of the present invention.

[0069] (1) Sample preparation

[0070] A plurality of copper alloy wires having a diameter of 0.074 mm and containing 10% by mass of silver and the remainder being copper and inevitable impurities are prepared (preparation step). Figure 2 The processing device shown in the figure moves the copper alloy wire at a certain speed, pushes the copper alloy wire 4.0 mm perpendicularly to the longitudinal direction, and rotates the copper alloy wire at a speed of 6000 rpm in the circumferential direction of the copper alloy wire (twisting processing step). That is, the angles α and β formed by the copper alloy wire 130 pushed by the second support part 212b and the conveying direction of the copper alloy wire are set to 30°, and the twisting processing amount is adjusted to 1 to 15 turns / mm.

[0071] Then, the copper alloy wire was subjected to torsion recovery or directly wound without torsion recovery (see Table 1). The torsion recovery amount was adjusted to be about 0.7% of the torsion processing amount (0.01 to 0.11 turns / mm).

[0072] (2) Sample evaluation

[0073] (2.1) Angle of fibrous tissue

[0074] Each sample of the wire for electrical characteristics test was ground down by 15 μm from the surface, and the ground surface was confirmed with a video microscope to confirm the angle between the length direction of the wire for electrical characteristics test and the extension direction of the fibrous structure. The results are shown in Tables 1 and Figure 3 shown.

[0075] (2.2) Determination of Vickers hardness and electrical conductivity

[0076] The hardness (Vickers hardness) of each sample of the wire for electrical properties test was measured using a Vickers hardness tester according to JIS Z 2244, and the conductivity was measured using a multimeter. The results are shown in Tables 1 and Figure 4 shown.

[0077] (2.3) Evaluation of processability

[0078] The handleability of each sample of the copper wire for electrical characteristics test was evaluated.

[0079] Specific as Figure 5As shown in FIG. 1 , a 100 cm sample was pulled out from the winding reel, and the length L when the end of the copper wire was kinked near the reel was measured, and the evaluation was performed based on the length L. The results are shown in Table 1. Here, only samples 12, 22, and 42 were representatively subjected to torsion recovery.

[0080] [Table 1]

[0081]

[0082] * The angle between the conductive length direction and the extension direction of the fibrous structure used for electrical properties testing

[0083] (3) Summary

[0084] As shown in Table 1 and Figure 3 As shown, from the comparison between sample 1 and other samples, it can be seen that when the copper alloy wire is pressed by a certain amount and twisted at a twisting amount of 1 to 60 turns / mm, the angle of the fibrous structure falls within the range of 0.5° to 20.0°, and the hardness of the wire is improved. At this time, the electrical conductivity is also improved by the twisting process.

[0085] If the above-mentioned twisting process is performed, the hardness is improved. This is because the twisting process gives a certain angle to the longitudinal direction in the fibrous structure, and the deformation resistance is increased. At the same time, the conductivity is also improved. It is speculated that this is because the strain in the longitudinal direction of the copper alloy wire is released and the electron scattering is suppressed, or because the solute elements contained in the parent phase are precipitated by the twisting process.

[0086] Furthermore, as can be seen from the comparison between Samples 11, 21, and 41 and Samples 12, 22, and 42, if the above-mentioned torsional recovery is performed, it is possible to suppress the occurrence of kinks in the copper alloy wire when it is pulled out from the reel.

[0087] This application claims the priority based on Japanese Patent Application No. 2022-093060 filed on June 8, 2022. The contents described in the specification and drawings of that application are incorporated herein by reference in their entirety.

[0088] Industrial Applicability

[0089] The electrical characteristic test wire of the present invention has both high hardness and high conductivity, so the electrical characteristic test wire can be used for various purposes such as contact probes or leads of electrical characteristic test devices.

[0090] Description of Reference Numerals

[0091] 10 Circuit board

[0092] 11 base plate

[0093] 12 Electrodes

[0094] 20 Contact probe

[0095] 21 Supporting part

[0096] 22 Probe

[0097] 30 Test equipment

[0098] 31. Maintaining part

[0099] 32 Lead

[0100] 100 Scrolls

[0101] 130 Copper Alloy Wire

[0102] 160 Scrolls

[0103] 170 Scroll

[0104] 200 Processing equipment

[0105] 211a First rotating plate

[0106] 211b Second rotating plate

[0107] 212a First supporting portion

[0108] 212b Second supporting portion

[0109] 212c Third supporting portion

Claims

1. A wire for testing electrical characteristics, comprising a copper alloy, wherein the copper alloy comprises 0.1 to 30% by mass of silver and the remainder is copper and unavoidable impurities, wherein the wire for testing electrical characteristics is characterized in that: The outer periphery has a fibrous structure extending in a direction forming an angle of 0.5° to 20° with respect to the longitudinal direction. The Vickers hardness is 300 HV or more and the electrical conductivity is 57% IACS or more.

2. The electrical characteristics testing wire according to claim 1, characterized in that: The fibrous tissue extends in a direction of an angle of 0.5° to 11.2°, The Vickers hardness is 320 HV or more and the electrical conductivity is 73.4% IACS or more.

3. A method for manufacturing a wire for electrical characteristic testing, characterized in that: have: A step of preparing a copper alloy wire having a composition of 0.1 to 30 mass % silver and the remainder being copper and unavoidable impurities; as well as The step of twisting the copper alloy wire by rotating the copper alloy wire in a circumferential direction of the copper alloy wire while conveying the copper alloy wire in one direction and pressing the copper alloy wire in a predetermined direction, In the step of twisting the copper alloy wire, the angle between the pressed copper alloy wire and the conveying direction of the copper alloy wire is set to 10° to 70°, and the rotation speed in the circumferential direction relative to the conveying speed of the copper alloy wire is set to 1 to 60 rpm.

4. The method for manufacturing a wire for electrical characteristic testing according to claim 3, characterized in that: In the step of twisting the copper alloy wire, the angle between the pressed copper alloy wire and the conveying direction of the copper alloy wire is set to 20° to 40°, and the rotation speed in the circumferential direction relative to the conveying speed of the copper alloy wire is set to 1 to 15 rpm.

5. The method for manufacturing a wire for electrical characteristic testing according to claim 3, characterized in that: have: A step of restoring the twist of the copper alloy wire by rotating the copper alloy wire in a direction opposite to the rotation direction during the twisting while conveying the twisted copper alloy wire in one direction.

6. The method for manufacturing a wire for electrical characteristic testing according to claim 5, characterized in that: In the step of restoring the twist of the copper alloy wire, the twist recovery amount is set to 0.02 to 3.0% of the twisting amount.

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