JP2010192130A - Electrical contact - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electrical contact in which solder transfer is prevented and which has conductivity. <P>SOLUTION: In the electrical contact has a conductive portion and a solder transfer control layer which has a contact surface with an electrode of an electronic component, the solder transfer control layer suppresses diffusion of metal or metal alloy inside the contact on the surface of the electric contact and can prevent solder transfer caused by repeated contact. Furthermore, the electrode and the conductive portion are in electrical conduction (for example, in conduction by a tunnel effect) via the solder transfer control layer. Consequently, solder transfer action can be suppressed, conduction is secured, and a stable contact performance can be obtained. For the solder transfer control layer, a nitride compound, a carbide compound, or an organic compound can be used. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrical contact that contacts an electrode formed of solder of an electronic component.

  Au (gold), Ag (silver), or platinum group metals such as Pt (platinum) and Pd (palladium) are excellent in conductivity, and are conventionally used as a protective layer on the surface of electrical contacts. However, for example, when Au is used as a protective layer, when it is connected to an electrode of an electronic component having solder on at least the surface, Au diffuses into the solder at the time of contact and combines with Sn (tin) contained in the solder. An Au—Sn-based intermetallic compound is generated. Since this intermetallic compound is fragile, when contact is repeated, it is deposited on the Au surface, so-called solder transfer occurs, and the contact performance becomes unstable. In addition, Au and solder are worn out and the contact life is shortened. When Ag or a platinum group metal is used as a protective layer, similar solder transfer occurs, and instability of contact performance has been a problem.

  With respect to the solder transfer at such an electrical contact, the following Patent Document 1 deals with the problem by exchanging the components of the solder transfer portion itself. Moreover, in the following patent document 2, the outermost layer is formed of a Cu (copper) -Sn intermetallic compound.

JP 2005-19343 A JP 2007-247060 A

  However, in the method of exchanging parts, there is a case where replacement parts are expensive and the parts cannot be exchanged. In addition, although an oxide film is formed on the surface of the Cu—Sn intermetallic compound and serves as a protective layer, the oxidation further proceeds depending on environmental conditions during use, and the film thickness changes.

  Therefore, the present invention is to solve the above-described conventional problems, and in particular, to provide an electrical contact having electrical conductivity that suppresses solder transfer by providing a solder transfer suppression layer on the surface of the electrical contact. It is an object.

The present invention is an electrical contact in contact with an electrode formed of solder of an electronic component,
A conductive portion and a solder transfer suppression layer having a contact surface with the electrode formed on the surface of the conductive portion, and the electrode and the conductive portion are electrically connected via the solder transfer suppression layer. It is a feature.

  Thereby, compared with the state which the electroconductive part exposed, while being able to suppress solder transfer, the electrical connection between an electrode and an electroconductive part can be ensured and the stable contact performance can be obtained.

In the present invention, the electrode and the conductive portion can be made conductive by a tunnel effect.
In the present invention, the solder transfer suppressing layer is preferably a nitride compound, a carbonized compound, or a combination thereof. Since the compound has high hardness, it has excellent wear resistance and is suitable as a surface of an electrical contact. In addition, an increase in contact resistance can be suppressed as compared with oxides and the like, and a stable contact resistance can be obtained.

The solder transfer suppressing layer is preferably at least one of TiN, NbN, TaN, WN ₂ , AlN, TiC, FeC, and CrC.

  The solder transfer suppressing layer may be an organic compound. Furthermore, it is preferable that the solder transfer suppressing layer is one of alkyl mercaptan and alkylamine, or a combination thereof.

  The solder transfer suppressing layer is formed with a thickness of 1 to 100 mm. By forming with such a thin film, electrical conduction between the electrode and the conductive portion can be appropriately ensured.

  According to the present invention, there is provided a support portion and an elastic arm extending from the support portion, and the support portion and the elastic arm are formed by the conductive portion, and at least on the surface of the elastic arm that contacts the electrode of the electronic component. The solder transfer suppressing layer can be formed.

  In the present invention, the conductive portion may be formed of Ni or a Ni alloy, or a surface layer made of Au, Ag, a platinum group metal, or an alloy of these metals may be formed on the surface.

  According to the electrical contact of the present invention, it is possible to suppress the transfer of solder as compared with the state in which the conductive portion is exposed, and it is possible to secure conduction between the electrode and the conductive portion and obtain stable contact performance.

The fragmentary sectional view which shows the electrical contact of the 1st Embodiment of this invention, The fragmentary sectional view which shows the electrical contact of the 2nd Embodiment of this invention, Partial sectional view of the connection device, The expanded sectional view which shows the electric contact vicinity of the connection apparatus shown in FIG. FIG. 4 is a plan view of the electrical contact shown in FIG. Sectional drawing (1st Embodiment) which shows the cut surface of the electrical contact cut | disconnected along the AA line of FIG. Sectional drawing (2nd Embodiment) which shows the cut surface of the electrical contact cut | disconnected along the AA line of FIG. Sectional drawing (3rd Embodiment) which shows the cut surface of the electrical contact cut | disconnected along the AA line of FIG. Sectional drawing (4th Embodiment) which shows the cut surface of the electrical contact cut | disconnected along the AA line of FIG.

  FIG. 1 is a partial cross-sectional view of an electrical contact according to a first embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of an electrical contact according to a second embodiment of the present invention.

  An electrical contact 1 shown in FIG. 1 includes a conductive portion 2 and a solder transfer suppressing layer 3 thereon. For the conductive part 2, a conductive metal or metal alloy is preferably used, and for example, Ni (nickel) or a Ni alloy can be used.

  The surface 3a of the solder transfer suppressing layer 3 is a contact surface with an electrode formed of solder of an electronic component. The solder transfer suppressing layer 3 is formed of a material having lower solder transferability than the conductive portion 2.

The solder transfer suppressing layer 3 is preferably made of a nitride compound or a carbonized compound. TiN (titanium nitride), NbN (niobium nitride), TaN (tantalum nitride), WN ₂ (tungsten nitride), and AlN (aluminum nitride) are preferably used as the nitride compound, and TiC (carbonized) as the carbonized compound. Titanium), FeC (iron carbide), and CrC (chromium carbide) are preferably used.

  Any one of these compounds may be used as the solder transfer suppressing layer 3, or two or more of them may be mixed or laminated to form the solder transfer suppressing layer 3.

  In the present embodiment, the conductive portion 2 and the electrodes of the electronic component are electrically connected via the solder transfer suppressing layer 3.

  When the solder transfer suppressing layer 3 is an electrically insulating material, the conductive portion 2 and the electrodes of the electronic component can be electrically connected by a tunnel effect.

  The solder transfer suppressing layer 3 is formed with a film thickness of about 1 to 100 mm. When two or more kinds of compounds are laminated, the film thickness of the entire solder transfer suppressing layer is 1 to 100 mm. The material forming the solder transfer suppressing layer 3 is made of an electrically insulating material, and when the film thickness is a thin film within the above range, the conductive portion 2 and the electrodes of the electronic component can be appropriately conducted by the tunnel effect. . If the film thickness is thick, the conductive portion 2 and the electrodes of the electronic component cannot be properly conducted, and the tunnel effect described above is particularly difficult to be exhibited. Therefore, the solder transfer suppressing layer 3 is preferably as thin as possible. However, since it is worn by repeated contact with the electrodes of the electronic component, a film thickness that does not disappear due to wear is required. From these viewpoints, the film thickness is preferably 1 to 50 mm, more preferably 1 to 30 mm, for example.

  When the solder transfer suppressing layer 3 is formed of, for example, a nitride compound or a carbonized compound, it can be formed using, for example, vacuum deposition or sputtering. For example, by using a plurality of targets, two or more kinds of compounds can be mixed or stacked. Moreover, when vacuum deposition or sputtering is used, the solder transfer suppressing layer 3 can be formed on any metal or metal alloy, and the film thickness to be formed can be easily controlled.

  Alternatively, when the solder transfer suppressing layer 3 is a nitride compound, for example, after forming a metal layer such as Ti, Nb, Ta, W, Al, etc., nitriding is performed to form the nitride compound solder transfer suppressing layer 3. Can do. In the case of a carbonized compound, for example, after forming a metal layer such as Ti, Fe, or Cr, carbonization treatment may be performed to form a solder transfer suppressing layer 3 of the carbonized compound.

  Since the solder transfer suppressing layer 3 is the outermost surface of the electrical contact 1, it is further required to have excellent wear resistance and high hardness. The aforementioned nitride compounds and carbonized compounds have high hardness and are preferably used as the solder transfer suppressing layer 3 of the electrical contact 1. It is particularly suitable for electrical contacts with high contact pressure.

  Alternatively, in this embodiment, the solder transfer suppressing layer 3 can be formed of an organic compound. As the organic compound, for example, alkyl mercaptan, alkylamine, or a combination thereof is preferably used. These organic compounds can be adsorbed on the surface of a metal or metal alloy to form a solid film. When the film thickness of the organic compound is about 1 to 100 mm, the conductive portion 2 and the electrodes of the electronic component can be appropriately and effectively conducted by the tunnel effect.

  Even when the solder transfer suppressing layer 3 is made of an organic compound, it is difficult to exhibit a tunnel effect when the film thickness is large. Therefore, it is preferable that the solder transfer suppressing layer 3 is as thin as possible, but wear due to repeated contact with the electrodes. Therefore, a film thickness that does not disappear is required. Therefore, the film thickness is further preferably, for example, 1 to 50 mm, more preferably 1 to 30 mm.

  The organic compound has a lower hardness than the nitride compound or the carbonized compound. Therefore, it is preferable to use the solder transfer suppression layer 3 of the electrical contact 1 having a low contact pressure applied to the contact. Further, the organic compound can be easily formed on the conductive portion 2 to form the solder transfer suppressing layer 3, and any metal or metal alloy can be formed on the surface thereof with the solder transfer suppressing layer 3. Can be formed.

The solder transfer suppressing layer 3 does not exclude materials other than nitride compounds, carbonized compounds, or organic compounds, but if it is a metal oxide (Al ₂ O ₃ , NiO, B ₂ O _3, etc.), the contact resistance is not stable, Also, with regard to solder transferability, it is easy to transfer the solder by breaking the oxide film by repeatedly contacting the electrode. Therefore, the solder transfer suppressing layer 3 is preferably formed of a nitride compound, a carbonized compound, or an organic compound rather than a metal oxide.

  The conductive part 2 constituting the electrical contact 5 shown in FIG. 2 is composed of a main layer 6 and a protective layer 4 formed on the surface thereof. Further, as shown in FIG. 2, a solder transfer suppressing layer 3 is formed on the surface of the protective layer 4. The main layer 6 is made of Ni, Ni alloy or the like. The solder transfer suppressing layer 3 is the same as the electrical contact 1 of the first embodiment.

  The protective layer 4 is provided to prevent oxidation of the main layer 6, and for example, Au, Ag, platinum group metals such as Pt and Pd, or alloys of these metals are preferably used.

  When Au, Ag, or a platinum group metal such as Pt or Pd, or an alloy of these metals is used as the outermost surface of the electrical contact, solder transfer due to diffusion of the metal into the solder becomes a problem. However, in the electrical contact 5, the solder transfer suppressing layer 3 is formed on the protective layer 4 formed of Au, Ag, platinum group metal such as Pt or Pd, or an alloy of these metals. The solder transfer suppressing film 3 has lower solder transferability than the protective layer 4. Therefore, since the solder transfer suppressing layer 3 effectively prevents the metal of the protective layer 4 from diffusing into the solder, the solder transfer suppressing layer 3 can be connected to the electrodes of the electronic component as compared with the conventional configuration in which the surface of the protective layer 4 is exposed. Solder transfer due to contact can be suppressed. The conductive portion 2 and the electrodes of the electronic component are electrically connected via the solder transfer suppressing layer 3. When the solder transfer suppressing layer 3 is formed of an electrically insulating material, the solder transfer suppressing layer 3 is formed sufficiently thin (about 1 to 100 mm) so as to conduct between the conductive portion 2 and the electrode of the electronic component by a tunnel effect. Thereby, it functions as an electrical contact having both suppression of solder transfer and conductivity.

  The electrical contact of the present invention can be used as an elastic contact, for example. The example used for the connection apparatus provided with the electrical contact which has an elastic arm as an example of an elastic contact is shown. 3 is a partial cross-sectional view of a connection device using the electrical contact of the present invention, FIG. 4 is an enlarged cross-sectional view showing the vicinity of the electrical contact of the connection device shown in FIG. 3, and FIG. 5 is a diagram of the electrical contact shown in FIG. FIG. 6 to FIG. 9 are sectional views showing respective cut surfaces of the electrical contacts cut along the line AA shown in FIG.

  A connecting device 9 shown in FIG. 3 has a base 10. The planar shape of the base 10 is, for example, a quadrangular shape, and side walls 10 a that rise substantially vertically are formed on each of the four sides of the base 10. A region surrounded by the four side wall portions 10 a is a concave portion, and the upper surface of the bottom portion 10 b is the support surface 12. A connection sheet 15 is installed on the support surface 12. The connection sheet 15 has a configuration in which, for example, a plurality of electrical contacts (contactors) 20 are provided on the surface of the flexible base sheet 16.

  As shown in FIG. 4, a large number of through holes 16 a are formed in the base sheet 16, and a conductor layer 17 is formed on the inner peripheral surface of each through hole 16 a by means such as plating. A front-side connection land 17 a that conducts to the conductor layer 17 is formed on the surface of the base material sheet 16, and a back-side connection land 17 b that conducts to the conductor layer 17 is formed on the back surface of the base material sheet 16. Yes.

  The electrical contacts 20 are formed by, for example, punching a thin conductive metal plate, and further plated, and each electrical contact 20 is joined to the surface of the connection land 17a with a conductive adhesive or the like. . Alternatively, the electrical contact 20 is formed by a plating process using a conductive material such as copper or nickel. For example, a plurality of electrical contacts 20 are formed by a plating process on the surface of a sheet separate from the substrate sheet 16, and the sheets are superimposed on the substrate sheet 16, and each electrical contact 20 is made of a conductive adhesive or the like. To be joined to the connection land 17a.

  After each electrical contact 20 is installed on the base sheet 16, for example, an external force is applied to form the three-dimensional shape. At this time, the internal residual stress is removed by the heat treatment, and the electrical contact 20 can exhibit an elastic force in a three-dimensional shape.

  As shown in FIG. 4, bump electrodes 18 made of a conductive material that are individually connected to the connection lands 17 b are formed on the back surface side of the base material sheet 16. As shown in FIG. 3, when the connection sheet 15 is placed on the support surface 12 that is the surface of the bottom portion 10 b of the base 10, the bump electrode 18 is connected to the conductive portion provided on the support surface 12.

  The arrangement pitch of the electrical contacts 20 on the support surface 12 is, for example, 2 mm or less, or 1 mm or less. The maximum value of the external dimension of the electrical contact 20 is also 2 mm or less, or 1 mm or less.

  The configuration of the connection sheet 15 is an example. For example, in FIG. 4, the through hole 16 a is provided in the base sheet 16, but the through hole 16 a may not be formed, and a wiring pattern that is electrically connected to the electrical contact 20 may be formed on the surface of the base sheet 16. .

  As shown in FIGS. 4 and 5, the electrical contact 20 includes a support portion 21 and an elastic arm 22 formed integrally and continuously. The elastic arm 22 is formed in, for example, a spiral shape, and a base end portion 22 a that is a winding start end of the elastic arm 22 is integrated with the support portion 21. The distal end portion 22b, which is the winding end of the elastic arm 22, is located substantially at the center of the spiral. In the form shown in FIG. 4, the support portion 21 constituting the electrical contact 20 is connected to the connection land 17 a, and the elastic arm 22 is three-dimensionally molded so that the tip end portion 22 b is separated from the support surface 12.

  The electrical contact 20 may be a planar shape without being three-dimensionally formed. The elastic arm 22 is not limited to a spiral shape. The elastic arm 22 may have a belt shape (straight shape), a curved shape, or the like. Further, only one side of the elastic arm 22 is supported by the support portion 21, but a configuration in which both sides are supported by the support portion may be employed.

  As shown in FIG. 3, an electronic component 40 is installed in the connection device 9. The electronic component 40 is an IC package or the like, and various electronic elements such as an IC bare chip are sealed in the main body 41. A plurality of protruding electrodes 42 having solder on at least the surface are provided on the bottom surface 41 a of the main body 41, and each protruding electrode 42 is electrically connected to a circuit in the main body 41. In the electronic component 40 of this embodiment, the protruding electrode 42 has a spherical shape. The protruding electrode 42 may have a truncated cone shape or the like.

  For example, the connection device 9 is used for inspecting the electronic component 40, and as shown in FIG. 3, the electronic component 40 that is an object to be inspected is mounted in the recess of the base 10. At this time, the electronic component 40 is positioned so that the individual protruding electrodes 42 provided on the bottom surface 41 a of the main body 41 are placed on the electrical contacts 20. A pressing lid (not shown) is provided on the base 10. When the lid is placed on the base 10, the electronic component 40 is pressed in the direction of arrow F by the lid. Due to this pressing force, each protruding electrode 42 is pressed against the elastic arm 22, the three-dimensional elastic arm 22 is crushed, and the protruding electrode 42 and the elastic arm 22 are individually connected to each other. An operation test of the circuit in the main body 41 is performed to determine whether or not the circuit in the circuit 41 is disconnected.

  As shown in the sectional views of FIGS. 6 and 7, the elastic arm 22 includes a conductive portion 30 and a solder transfer suppressing layer 33 that covers the upper surface of the conductive portion 30 or the entire circumference of the surface. The conductive portion 30 is preferably one in which the entire circumference around the core portion 31 is covered with the elastic layer 32. The core part 31 is a single layer of copper (Cu) or an alloy containing copper, for example. As the copper alloy, a Corson alloy having Cu, Si, Ni having high electric conductivity and high mechanical strength is preferably used. The Corson alloy is, for example, Cu—Ni—Si—Mg, Cu is 96.2 mass%, Ni is 3.0 mass%, Si (silicon) is 0.65 mass%, and Mg (magnesium) is 0.15 mass. % Are used.

  The elastic layer 32 is a metal material that is electrically conductive and exhibits high mechanical strength and high flexural modulus, and is a nickel (Ni) layer or an alloy layer containing Ni. Ni alloy is Ni-X alloy (where X is one or more of P (phosphorus), W (tungsten), Mn (manganese), Ti, Be (beryllium), Co (cobalt), B (boron)). Is used. The elastic layer 32 is formed by performing electrolytic plating or electroless plating around the core portion 31. The elastic layer 32 is preferably a Ni-P alloy formed by electroless plating. In the Ni-P alloy, by setting the concentration of phosphorus (P) to 10 at% or more and 30 at% or less (more preferably 17 to 25 at%), at least a part becomes amorphous (preferably the whole is amorphous). ), High elastic modulus and high tensile strength can be obtained. Alternatively, the elastic layer 32 is formed of a Ni—W alloy. Also in this case, by setting the tungsten (W) concentration to 10 at% or more and 30 at% or less, at least a part becomes amorphous (preferably the whole is amorphous), and a high elastic modulus and a high tensile strength can be obtained. Can do.

  In FIG. 6, the cross-sectional area of the elastic layer 32 is preferably 20% or more and 80% or less of the cross-sectional area of the core portion 31. Within this range, the core part 31 can exhibit both functions of conductivity and springiness (elasticity). In the cross-sectional view of FIG. 6, it is preferable that the thickness dimension and the width dimension of the core part 31 are both 10 μm or more and 100 μm or less.

  However, since the elastic layer 32 has conductivity and elasticity, the core portion 31 may not be formed, and the conductive portion 30 may be formed only by the elastic layer 32.

  As shown in FIG. 6, the solder transfer suppressing layer 33 of the present invention is formed on the upper surface of the conductive portion 30. The solder transfer suppressing layer 33 is formed on the surface of the conductive portion 30 that is in contact with at least the protruding electrode 42. As shown in FIG. 6, it may be formed only on the upper surface of the conductive part 30, or may be formed so as to completely surround the conductive part 30 as shown in FIG. Alternatively, the conductive portion 30 may be formed on the upper surface and the lower surface.

  Alternatively, as shown in FIG. 8, the solder transfer suppressing layer 33 can be provided on the protective layer 34 formed on the upper surface of the elastic layer 32 shown in FIG. 6, for example. In FIG. 8, the conductive layer 30 is formed by the elastic layer 32 and the protective layer 34.

  Also in this case, the solder transfer suppressing layer 33 is formed on at least the surface of the protective layer 34 in contact with the protruding electrode 42. As shown in FIG. 8, it may be formed only on the upper surface of the protective layer 34, or may be formed so as to completely surround the protective layer 34 as shown in FIG. Alternatively, it may be configured to be formed on the upper and lower surfaces of the protective layer 34 shown in FIG. The protective layer 34 may also be provided only on the upper surface of the elastic layer 32 or may be provided so as to surround the elastic layer 32. The conductive portion 30 may be formed by a laminated structure of the core portion 31 and the elastic layer 32 shown in FIG. 6 and the protective layer 34 shown in FIGS.

  In any case, the solder transfer suppressing layer 33 is formed on the surface of the conductive portion 30 having the conductivity and elasticity of the elastic arm 22 in contact with the protruding electrode 42. Thereby, even if the elastic arm 22 is repeatedly contacted with the protruding electrode 42 having solder, it is difficult to cause the solder transfer, and it is possible to ensure electrical conductivity between the conductive portion 30 and the protruding electrode 42, and stable contact performance. Can be obtained.

  In particular, when the elastic arm 22 is three-dimensionally formed as shown in FIG. 4, the contact pressure applied to the elastic arm 22 when contacting the protruding electrode 42 is large. In that case, the solder transfer suppressing layer 33 is preferably made of a compound having high hardness such as a nitride compound or a carbonized compound.

Example 1
An electrical contact 20 having an elastic arm 22 having an elastic layer 32 formed on the surface of the core portion 31 and a protective layer 34 formed on the surface of the elastic layer 32 was produced. The core portion 31 is made of a Corson alloy, the elastic layer 32 is plated with a high P content (20 at%) Ni—P alloy, and a Pd—Ni alloy is plated thereon with a thickness of 0.5 μm. The protective layer 34 was formed. On the protective layer 34, TiN was formed to a thickness of 20 mm by vacuum deposition to form a solder transfer suppressing layer 33.

(Example 2)
An electrical contact 20 having an elastic arm 22 was prepared in the same manner as in Example 1 except that an organic perfluoroalkyl mercaptan was formed in a thickness of 30 mm instead of TiN. Organic perfluoroalkyl mercaptans were formed by an immersion chemical reaction.

  The contacts of the above (Example 1) and (Example 2) were both electrically connected to the protruding electrode 42 having solder on the surface. Moreover, the contact test of the electrical component was performed using the contact of (Example 1) and (Example 2), but no solder transfer to the contact was observed even after 1000 times contact.

DESCRIPTION OF SYMBOLS 1,5,20 Electrical contact 2,30 Conductive part 3,33 Solder transfer suppression layer 4,34 Protective layer 9 Connection apparatus 10 Base 10a Base side wall 10b Base bottom 12 Support surface 15 Connection sheet 16 Base material Sheet 16a Through hole 17 Conductor layer 17b Connection land 18 Bump electrode 21 Support part 22 Elastic arm 31 Core part 32 Elastic layer 40 Electronic component 41 Main part 41a of electronic part Bottom face 42 of main part Projecting electrode

Claims (9)

In electrical contacts that come into contact with electrodes formed with solder of electronic components,
A conductive portion and a solder transfer suppression layer having a contact surface with the electrode formed on the surface of the conductive portion, and the electrode and the conductive portion are electrically connected via the solder transfer suppression layer. Characteristic electrical contact.   The electrical contact according to claim 1, wherein the electrode and the conductive portion are electrically connected by a tunnel effect.   The electrical contact according to claim 1, wherein the solder transfer suppressing layer is formed of a nitride compound, a carbonized compound, or a combination thereof. The electrical contact according to claim 3, wherein the solder transfer suppressing layer is formed of at least one of TiN, NbN, TaN, WN ₂ , AlN, TiC, FeC, and CrC.   The electrical contact according to claim 1, wherein the solder transfer suppressing layer is formed of an organic compound.   The electrical contact according to claim 5, wherein the solder transfer suppressing layer is formed of one of alkyl mercaptan and alkyl amine, or a combination thereof.   The electrical contact according to claim 1, wherein the solder transfer suppressing layer has a thickness of 1 to 100 mm.   A solder transfer suppressing layer formed on the surface of the elastic arm that is at least in contact with the electrode of the electronic component, the support portion and the elastic arm being formed by the conductive portion; The electrical contact according to claim 1, wherein: is formed.   The conductive part is formed of Ni or Ni alloy, or a protective layer made of Au, Ag, a platinum group metal, or an alloy of these metals is formed on the surface. Electrical contacts.

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