Press-fit terminal and electronic component using the same

Information

  • Patent Grant
  • 9728878
  • Patent Number
    9,728,878
  • Date Filed
    Wednesday, January 30, 2013
    11 years ago
  • Date Issued
    Tuesday, August 8, 2017
    6 years ago
Abstract
There are provided a press-fit terminal which has an excellent whisker resistance and a low inserting force, is unlikely to cause shaving of plating when the press-fit terminal is inserted into a substrate, and has a high heat resistance, and an electronic component using the same. A press-fit terminal comprises: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate. At least the substrate connection part has the surface structure described below, and the press-fit terminal has an excellent whisker resistance. The surface structure comprises: an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof; a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu. The A layer has a thickness of 0.002 to 0.2 μm. The B layer has a thickness of 0.001 to 0.3 μm. The C layer has a thickness of 0.05 μm or larger.
Description
TECHNICAL FIELD

The present invention relates to a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, and an electronic component using the same.


BACKGROUND ART

A press-fit terminal is an acicular terminal having compressive elasticity, and is press-fitted into a through-hole formed in a substrate, to ensure a frictional force (retaining force), thereby being mechanically and electrically fixed to the substrate. A copper-plated electrode portion is formed on an inner circumferential surface of a conventional through-hole. The electrode portion contributes to a retaining force between the through-hole and a press-fit terminal pin. A male connector (plug connector) is attached to the press-fit terminal fixed to the substrate, and is fitted to a female connector (receptacle connector), thereby establishing electrical connection. The surface of a terminal for the press-fit terminal is mainly subjected to Sn plating in order to improve a contact property with a through-hole of a connection substrate in light of lead free.


This press-fit terminal connects a connection terminal and a control substrate without performing conventional soldering. It is not assumed that the press-fit terminal once inserted into the through-hole is extracted from the through-hole again. Therefore, as a matter of course, a person cannot insert the terminal for the press-fit terminal into the through-hole with a hand. For example, when the terminal for the press-fit terminal is inserted into the through-hole, a normal force of 6 to 7 kg (60 to 70 N) per terminal is required. A significant pushing force is required in a connector subjected to molding, because 50 to 100 terminals are simultaneously used as the press-fit terminal.


For this reason, when the terminal for the press-fit terminal is inserted into the through-hole, the outer periphery of the press-fit terminal is subjected to a large welding pressure by the through-hole; comparatively soft Sn plating is shaven; and the shaven pieces are dispersed around, which disadvantageously causes short-circuit between the adjacent terminals depending on the case.


By contrast, a press-fit terminal inserted into a conductive through-hole of a substrate in a press-fit state is described in Patent Literature 1. In the press-fit terminal, at least a substrate inserting portion of the press-fit terminal is subjected to tin plating with a thickness of 0.1 to 0.8 μm, and the portion for which the tin plating is carried out is subjected to copper intermediate layer plating with a thickness of 0.5 to 1 μm and nickel base plating with a thickness of 1 to 1.3 μm, thereby to enable the suppression of the shaving of the tin plating.


A press-fit terminal is described in Patent Literature 2. In the press-fit terminal, a base plating layer made of Ni or a Ni alloy is provided on the entire surface of a base material. A Cu—Sn alloy layer and a Sn layer are sequentially provided on the surface of the base plating layer of the female terminal connection part of the base material, or a Cu—Sn alloy layer and a Sn alloy layer are sequentially provided on the surface. Alternatively, a Au alloy layer is provided on the surface. A Cu3Sn alloy layer and a Cu6Sn5 alloy layer are sequentially provided on the surface of the base plating layer of the substrate connection part of the base material, and Sn is not exposed on the surface of the Cu6Sn5 alloy layer. Thereby, the generation of shaving offscum of the Sn plating can be suppressed as compared with Patent Literature 1; and a synergistic effect obtained by providing the soft Sn layer or Sn alloy layer on the hard Cu—Sn alloy layer can improve a coefficient of friction to thereby weaken an inserting force when a terminal for press-fit is inserted into the through-hole.


CITATION LIST
Patent Literature



  • Patent Literature 1—Japanese Patent Laid-Open No. 2005-226089

  • Patent Literature 2—Japanese Patent Laid-Open No. 2010-262861



SUMMARY OF INVENTION
Technical Problem

However, in the technique described in Patent Literature 1, whiskers are generated in the mechanical/electrical connection part between the conductive through-hole of the substrate and the press-fit terminal; a sufficiently low inserting force cannot be acquired; the plating is shaven to thereby generate the shaving offscum; and a sufficiently high heat resistance cannot be acquired although a heat resistance has been required at 175° C. in USACAR specification in recent years.


Also in the technique described in Patent Literature 2, a press-fit terminal is not achieved, which has an excellent whisker resistance and a low inserting force, is unlikely to cause shaving of plating when the press-fit terminal is inserted into a substrate, and has a high heat resistance.


Thus, the press-fit terminal subjected to the conventional Sn plating has problems of a whisker resistance, an inserting force, shaving of plating when the press-fit terminal is inserted into the substrate, and a heat resistance.


The present invention has been achieved to solve the above-mentioned problems, and an object thereof is to provide a press-fit terminal which has an excellent whisker resistance and a low inserting force, is unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, and has a high heat resistance, and an electronic component using the same.


Solution to Problem

The present inventors have found that a press-fit terminal which has an excellent whisker resistance and a low inserting force can be provided by using a metal material obtained by sequentially forming an A layer, a B layer, and a C layer formed at a predetermined thickness by using a predetermined metal from an outermost surface layer, and thereby a press-fit terminal which is unlikely to cause shaving of plating when the press-fit terminal is inserted into a substrate, and has a high heat resistance can be fabricated.


One aspect of the present invention completed based on the above finding is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal has an excellent whisker resistance; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a thickness of 0.002 to 0.2 μm;


the B layer has a thickness of 0.001 to 0.3 μm; and


the C layer has a thickness of 0.05 μm or larger.


Another aspect of the present invention is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal has a low inserting force; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a thickness of 0.002 to 0.2 μm;


the B layer has a thickness of 0.001 to 0.3 μm; and


the C layer has a thickness of 0.05 μm or larger.


Further another aspect of the present invention is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal is unlikely to cause shaving of plating when the press-fit terminal is inserted; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a thickness of 0.002 to 0.2 μm;


the B layer has a thickness of 0.001 to 0.3 μm; and


the C layer has a thickness of 0.05 μm or larger.


Further another aspect of the present invention is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal has an excellent heat resistance; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a thickness of 0.002 to 0.2 μm;


the B layer has a thickness of 0.001 to 0.3 μm; and


the C layer has a thickness of 0.05 μm or larger.


Further another aspect of the present invention is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal has an excellent whisker resistance; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a deposition amount of Sn, In of 1 to 150 μg/cm2;


the B layer has a deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir of 1 to 330 μg/cm2; and


the C layer has a deposition amount of Ni, Cr, Mn, Fe, Co, Cu of 0.03 mg/cm2 or larger.


Further another aspect of the present invention is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal has a low inserting force; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a deposition amount of Sn, In of 1 to 150 μg/cm2;


the B layer has a deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir of 1 to 330 μg/cm2; and


the C layer has a deposition amount of Ni, Cr, Mn, Fe, Co, Cu of 0.03 mg/cm2 or larger.


Further another aspect of the present invention is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal is unlikely to cause shaving of plating when the press-fit terminal is inserted; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a deposition amount of Sn, In of 1 to 150 μg/cm2;


the B layer has a deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir of 1 to 330 μg/cm2; and


the C layer has a deposition amount of Ni, Cr, Mn, Fe, Co, Cu of 0.03 mg/cm2 or larger.


Further another aspect of the present invention is a press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; and a substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate, wherein at least the substrate connection part has the surface structure described below, and the press-fit terminal has an excellent heat resistance; the surface structure comprises:


an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;


a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and


a C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; wherein


the A layer has a deposition amount of Sn, In of 1 to 150 μg/cm2;


the B layer has a deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir of 1 to 330 μg/cm2; and


the C layer has a deposition amount of Ni, Cr, Mn, Fe, Co, Cu of 0.03 mg/cm2 or larger.


In one embodiment of the press-fit terminal according to the present invention, the A layer has an alloy composition comprising 50 mass % or more of Sn, In, or a total of Sn and In, and the other alloy component(s) comprising one or two or more metals selected from the group consisting of Ag, As, Au, Bi, Cd, Co, Cr, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Sn, W, and Zn.


In another embodiment of the press-fit terminal according to the present invention, the B layer has an alloy composition comprising 50 mass % or more of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir, or a total of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir, and the other alloy component(s) comprising one or two or more metals selected from the group consisting of Ag, Au, Bi, Cd, Co, Cu, Fe, In, Ir, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Ru, Sb, Se, Sn, W, Tl, and Zn.


In further another embodiment of the press-fit terminal according to the present invention, the C layer has an alloy composition comprising 50 mass % or more of a total of Ni, Cr, Mn, Fe, Co, and Cu, and further comprising one or two or more selected from the group consisting of B, P, Sn, and Zn.


In further another embodiment of the press-fit terminal according to the present invention, a Vickers hardness as measured from the surface of the A layer is Hv100 or higher.


In further another embodiment of the press-fit terminal according to the present invention, the A layer has a surface indentation hardness of 1,000 MPa or higher, the indentation hardness being a hardness acquired by measuring an impression made on the surface of the A layer by a load of 0.1 mN in an ultrafine hardness test.


In further another embodiment of the press-fit terminal according to the present invention, a Vickers hardness as measured from the surface of the A layer is Hv1,000 or lower, and the press-fit terminal has high bending workability.


In further another embodiment of the press-fit terminal according to the present invention, the A layer has a surface indentation hardness of 10,000 MPa or lower, the indentation hardness being a hardness acquired by measuring an impression made on the surface of the A layer by a load of 0.1 mN in an ultrafine hardness test, and the press-fit terminal has high bending workability.


In further another embodiment of the press-fit terminal according to the present invention, the A layer has a surface arithmetic average height (Ra) of 0.1 μm or lower.


In further another embodiment of the press-fit terminal according to the present invention, the A layer has a surface maximum height (Rz) of 1 μm or lower.


In further another embodiment of the press-fit terminal according to the present invention, the A layer has a surface reflection density of 0.3 or higher.


In further another embodiment of the press-fit terminal according to the present invention, when a depth analysis by XPS (X-ray photoelectron spectroscopy) is carried out, a position (D1) where an atomic concentration (at %) of Sn or In of the A layer is a maximum value, a position (D2) where an atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of the B layer is a maximum value, and a position (D3) where an atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, or Cu of the C layer is a maximum value are present in the order of D1, D2, and D3 from the outermost surface.


In further another embodiment of the press-fit terminal according to the present invention, when a depth analysis by XPS (X-ray photoelectron spectroscopy) is carried out, the A layer has a maximum value of an atomic concentration (at %) of Sn or In of 10 at % or higher, and the B layer has a maximum value of an atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of 10 at % or higher; and a depth where the C layer has an atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, or Cu of 25% or higher is 50 nm or more.


In further another embodiment of the press-fit terminal according to the present invention, the A layer has a thickness of 0.01 to 0.1 μm.


In further another embodiment of the press-fit terminal according to the present invention, the A layer has a deposition amount of Sn, In of 7 to 75 μg/cm2.


In further another embodiment of the press-fit terminal according to the present invention, the B layer has a thickness of 0.005 to 0.1 μm.


In further another embodiment of the press-fit terminal according to the present invention, the B layer has a deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir of 4 to 120 μg/cm2.


In further another embodiment of the press-fit terminal according to the present invention, the C layer has a cross-section Vickers hardness of Hv300 or higher.


In further another embodiment of the press-fit terminal according to the present invention, the cross-section Vickers hardness and the thickness of the C layer satisfy the following expression:

Vickers hardness(Hv)≧−376.22 Ln(thickness:μm)+86.411.


In further another embodiment of the press-fit terminal according to the present invention, the underlayer (C layer) has a cross-section indentation hardness of 2,500 MPa or higher, the indentation hardness being a hardness acquired by measuring an impression made on the cross-section of the underlayer (C layer) by a load of 0.1 mN in an ultrafine hardness test.


In further another embodiment of the press-fit terminal according to the present invention, the cross-section indentation hardness, which is a hardness acquired by measuring an impression made on the cross-section of the underlayer (C layer) by a load of 0.1 mN in an ultrafine hardness test, and the thickness of the underlayer (C layer) satisfy the following expression:

Indentation hardness(MPa)≧−3998.4 Ln(thickness:μm)+1178.9.


In further another embodiment of the press-fit terminal according to the present invention, the C layer has a cross-section Vickers hardness of Hv1,000 or lower.


In further another embodiment of the press-fit terminal according to the present invention, the underlayer (C layer) has a cross-section indentation hardness of 10,000 MPa or lower, the indentation hardness being a hardness acquired by measuring an impression made on the cross-section of the underlayer (C layer) by a load of 0.1 mN in an ultrafine hardness test.


In further another embodiment of the press-fit terminal according to the present invention, when a depth analysis by XPS (X-ray photoelectron spectroscopy) is carried out, between a position (D1) where an atomic concentration (at %) of Sn or In of the A layer is a maximum value and a position (D3) where an atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, Cu, or Zn of the C layer is a maximum value, a region having 40 at % or more of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir is present in a thickness of 1 nm or larger.


In further another embodiment of the press-fit terminal according to the present invention, when an elemental analysis of a surface of the A layer is carried out by a survey measurement by XPS (X-ray photoelectron spectroscopy), a content of Sn, In is 2 at % or higher.


In further another embodiment of the press-fit terminal according to the present invention, when an elemental analysis of a surface of the A layer is carried out by a survey measurement by XPS (X-ray photoelectron spectroscopy), a content of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir is lower than 7 at %.


In further another embodiment of the press-fit terminal according to the present invention, when an elemental analysis of a surface of the A layer is carried out by a survey measurement by XPS (X-ray photoelectron spectroscopy), a content of O is lower than 50 at %.


In further another embodiment of the press-fit terminal according to the present invention, the press-fit terminal is fabricated by forming surface-treated layers on the substrate connection part in the order of the C layer, the B layer, and the A layer by a surface treatment, and thereafter heat-treating the surface-treated layers at a temperature of 50 to 500° C. within 12 hours.


Further another aspect of the present invention is an electronic component comprising the press-fit terminal according to the present invention.


Advantageous Effects of Invention

The present invention can provide a press-fit terminal which has an excellent whisker resistance and a low inserting force, is unlikely to cause shaving of plating when the press-fit terminal is inserted into a substrate, and has a high heat resistance, and an electronic component using the same.





BRIEF DESCRIPTION OF DRAWINGS


FIG. 1 is an illustrative diagram of a press-fit terminal according to an embodiment of the present invention.



FIG. 2 is an illustrative diagram showing a constitution of a metal material used for the press-fit terminal according to the embodiment of the present invention.



FIG. 3 is a depth measurement result by XPS (X-ray photoelectron spectroscopy) according to Example 3.



FIG. 4 is a survey measurement result by XPS (X-ray photoelectron spectroscopy) according to Example 3.



FIG. 5 is a an illustrative drawing of a press-fit terminal according to an embodiment of the invention.





DESCRIPTION OF EMBODIMENTS

Hereinafter, a press-fit terminal according to an embodiment of the present invention will be described. FIG. 1 is an illustrative diagram of a press-fit terminal according to the embodiment. As shown in FIG. 2, in a metal material 10 used as a material of the press-fit terminal, a C layer 12 is formed on the surface of a base material 11; a B layer 13 is formed on the surface of the C layer 12; and an A layer 14 is formed on the surface of the B layer 13.



FIG. 5 is a an illustrative drawing of a press-fit terminal according to an embodiment of the invention, generally designated as 2. A female terminal connection part 4 of the press-fit terminal 2 is provided at one side of an attached part 6. Attached part 6 is attached to housing 8. A substrate connection part 20 is provided at the other side of the press-fit terminal 2. The substrate connection part 20 is attached to a substrate 22 by press-fitting the substrate connection part into through-hole 24 formed in the substrate.


Constitution of Press-Fit Terminal


Base Material


The base material 11 is not especially limited, but usable are metal base materials, for example, copper and copper alloys, Fe-based materials, stainless steels, titanium and titanium alloys, and aluminum and aluminum alloys. The structure and shape or the like of the press-fit terminal are not especially limited. A general press-fit terminal includes a plurality of terminals (multi-pin) arranged in parallel, and is fixed to a substrate.


A Layer


The A layer needs to be Sn, In, or an alloy thereof. Sn and In, though being oxidative metals, have a feature of being relatively soft among metals. Therefore, even if an oxide film is formed on the Sn and In surface, when the press-fit terminal is inserted into the substrate, since the oxide film is easily shaven to thereby make the contact of metals, a low contact resistance can be provided.


Sn and In are excellent in the gas corrosion resistance to gases such as chlorine gas, sulfurous acid gas, and hydrogen sulfide gas; and for example, in the case where Ag, inferior in the gas corrosion resistance, is used for the B layer 13; Ni, inferior in the gas corrosion resistance, is used for the C layer 12; and copper and a copper alloy, inferior in the gas corrosion resistance, are used for the base material 11, Sn and In have a function of improving the gas corrosion resistance of the press-fit terminal. Here, among Sn and In, Sn is preferable because In is under a strict regulation based on the technical guideline regarding the health hazard prevention of the Ministry of Health, Labor, and Welfare.


The composition of the A layer 14 comprises 50 mass % or more of Sn, In, or the total of Sn and In, and the other alloy component(s) may be constituted of one or two or more metals selected from the group consisting of Ag, As, Au, Bi, Cd, Co, Cr, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Sn, W, and Zn. The composition of the A layer 14 forms an alloy (for example, the A layer is subjected to Sn—Ag plating), and thereby, the composition further improves a whisker resistance, provides a further low inserting force, is further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, and improves a heat resistance in some cases.


The thickness of the A layer 14 needs to be 0.002 to 0.2 μm. The thickness of the A layer 14 is preferably 0.01 to 0.1 μm. With the thickness of the A layer 14 of smaller than 0.002 μm, a sufficient gas corrosion resistance cannot be provided; and when the press-fit terminal is subjected to a gas corrosion test using chlorine gas, sulfurous acid gas, hydrogen sulfide gas, or the like, the press-fit terminal is corroded to thereby largely increase the contact resistance as compared with before the gas corrosion test. In order to provide a more sufficient gas corrosion resistance, the thickness is preferably 0.01 μm or larger. If the thickness becomes large, the adhesive wear of Sn and In becomes much; the inserting force becomes high; and the plating is liable to be shaven when the press-fit terminal is inserted into the substrate. In order to provide a more sufficiently low inserting force and be further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, the thickness is made to be 0.2 μm or smaller. The thickness is more preferably 0.15 μm or smaller, and still more preferably 0.10 μm or smaller.


The deposition amount of Sn, In of the A layer 14 needs to be 1 to 150 μg/cm2. The deposition amount of the A layer 14 is preferably 7 to 75 μg/cm2. Here, the reason to define the deposition amount will be described. For example, in some cases of measuring the thickness of the A layer 14 by an X-ray fluorescent film thickness meter, due to an alloy layer formed between the A layer and the underneath B layer, an error may be produced in the value of the measured thickness. By contrast, the case of the control using the deposition amount can carry out more exact quality control, not influenced by the formation situation of the alloy layer. If the deposition amount of Sn, In of the A layer 14 is smaller than 1 μg/cm2, a sufficient gas corrosion resistance cannot be provided. If the press-fit terminal is subjected to a gas corrosion test using chlorine gas, sulfurous acid gas, hydrogen sulfide gas, or the like, the press-fit terminal is corroded to thereby largely increase the contact resistance as compared with before the gas corrosion test. In order to provide a more sufficient gas corrosion resistance, the deposition amount is preferably 7 μg/cm2 or larger. If the deposition amount becomes large, the adhesive wear of Sn and In becomes much; the inserting force becomes high; and the plating is liable to be shaven when the press-fit terminal is inserted into the substrate. In order to provide a more sufficiently low inserting force and be further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, the deposition amount is made to be 150 μg/cm2 or smaller. The deposition amount is more preferably 110 μg/cm2 or smaller, and still more preferably 75 μg/cm2 or smaller.


B Layer


The B layer 13 needs to be constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir. Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir have a feature of relatively having a heat resistance among metals. Therefore, the B layer suppresses the diffusion of the compositions of the base material 11 and the C layer 12 to the A layer 14 side, and improves the heat resistance. These metals form compounds with Sn and In of the A layer 14 and suppress the oxide film formation of Sn and In. Among Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir, Ag is more desirable from the viewpoint of the conductivity. Ag has high conductivity. For example, in the case of using Ag for applications of high-frequency signals, the skin effect reduces the impedance resistance.


The alloy composition of the B layer 13 comprises 50 mass % or more of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir, or the total of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir, and the other alloy component(s) may be constituted of one or two or more metals selected from the group consisting of Ag, Au, Bi, Cd, Co, Cu, Fe, In, Ir, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Ru, Sb, Se, Sn, W, Tl, and Zn. The composition of the B layer 13 forms an alloy (for example, the B layer is subjected to Ag—Sn plating), and thereby, the composition further improves a whisker resistance, provides a further low inserting force, is further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, and improves a heat resistance in some cases.


The thickness of the B layer 13 needs to be 0.001 to 0.3 μm. The thickness of the B layer 13 is preferably 0.005 to 0.1 μm. If the thickness is smaller than 0.001 μm, the base material 11 or the C layer 12 and the A layer form an alloy, and the contact resistance after a heat resistance test becomes worsened. In order to provide a more sufficient heat resistance, the thickness is preferably 0.005 μm or larger. If the thickness becomes large, the inserting force becomes high; and the plating is liable to be shaven when the press-fit terminal is inserted into the substrate. In order to provide a more sufficiently low inserting force and be further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, the thickness is 0.3 μm or smaller, more preferably 0.15 μm or smaller, and more preferably 0.10 μm or smaller.


The deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir, or an alloy thereof of the B layer 13 needs to be 1 to 330 μg/cm2. The deposition amount of the B layer 13 is preferably 4 to 120 μg/cm2. Here, the reason to define the deposition amount will be described. For example, in some cases of measuring the thickness of the B layer 13 by an X-ray fluorescent film thickness meter, due to an alloy layer formed between the A layer 14 and the underneath B layer 13, an error may be produced in the value of the measured thickness. By contrast, the case of the control using the deposition amount can carry out more exact quality control, not influenced by the formation situation of the alloy layer. With the deposition amount of smaller than 1 μg/cm2, the base material 11 or the C layer 12 and the A layer form an alloy, and the contact resistance after a heat resistance test becomes worsened. In order to provide a more sufficient heat resistance, the deposition amount is preferably 4 μg/cm2 or larger. If the deposition amount is large, the inserting force becomes high; and the plating is liable to be shaven when the press-fit terminal is inserted into the substrate. In order to provide a more sufficiently low inserting force and be further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, the deposition amount is 330 μg/cm2 or smaller, more preferably 180 μg/cm2 or smaller, and still more preferably 120 μg/cm2 or smaller.


C Layer


Between the base material 11 and the B layer 13, the C layer 12 constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu needs to be formed. By forming the C layer 12 by using one or two or more metals selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu, the thin film lubrication effect is improved due to the formation of the hard C layer, and thereby a sufficiently low inserting force can be provided. The C layer 12 prevents the diffusion of constituting metals of the base material 11 to the B layer to thereby improve the durability including the suppression of the increase in the contact resistance after the heat resistance test and the gas corrosion resistance test.


The alloy composition of the C layer 12 comprises 50 mass % or more of the total of Ni, Cr, Mn, Fe, Co, and Cu, and may further comprise one or two or more selected from the group consisting of B, P, Sn, and Zn. By making the alloy composition of the C layer 12 to have such a constitution, the C layer is further hardened to thereby further improve the thin film lubrication effect to provide the low inserting force; and the alloying of the C layer 12 further prevents the diffusion of constituting metals of the base material 11 to the B layer to thereby improve the durability including the suppression of the increase in the contact resistance after the heat resistance test and the gas corrosion resistance test.


The thickness of the C layer 12 needs to be 0.05 μm or larger. With the thickness of the C layer 12 of smaller than 0.05 μm, the thin film lubrication effect by the hard C layer decreases to thereby provide the high inserting force; and the constituting metals of the base material 11 become liable to diffuse to the B layer to thereby worsen the durability including the increase in the contact resistance after the heat resistance test and the gas corrosion resistance test.


The deposition amount of Ni, Cr, Mn, Fe, Co, Cu of the C layer 12 needs to be 0.03 mg/cm2 or larger. Here, the reason to define the deposition amount will be described. For example, in some cases of measuring the thickness of the C layer 12 by an X-ray fluorescent film thickness meter, due to alloy layers formed with the A layer 14, the B layer 13, the base material 11, or the like, an error may be produced in the value of the measured thickness. By contrast, the case of the control using the deposition amount can carry out more exact quality control, not influenced by the formation situation of the alloy layer. With the deposition amount of smaller than 0.03 mg/cm2, the thin film lubrication effect by the hard C layer decreases to thereby provide the high inserting force; and the constituting metals of the base material 11 become liable to diffuse to the B layer to thereby worsen the durability including the increase in the contact resistance after the heat resistance test and the gas corrosion resistance test.


Heat Treatment


After the A layer 14 is formed, for the purpose of further improving a whisker resistance, providing a further low inserting force, being further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, or improving a heat resistance, a heat treatment may be carried out. The heat treatment makes it easy for the A layer 14 and the B layer 13 to form an alloy layer to thereby improve the whisker resistance, to be thereby further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, to thereby improve the heat resistance, and to thereby provide further low adhesion of Sn to provide a low inserting force. Here, the heat treatment is not limited. However, the heat treatment is preferably carried out at a temperature of 50 to 500° C. within 12 hours. If the temperature is lower than 50° C., the A layer 14 and the B layer 13 hardly form the alloy layer because of the low temperature. If the temperature is higher than 500° C., the base material 11 or the C layer 12 diffuses to the B layer 13 and the A layer 14 to thereby provide the high contact resistance in some cases. If the heat treatment time is longer than 12 hours, the base material 11 or the C layer 12 diffuses to the B layer 13 and the A layer 14 to thereby provide the high contact resistance in some cases.


Post-Treatment


On the A layer 14 or after the heat treatment is carried out on the A layer 14, for the purpose of providing a further low inserting force, being further unlikely to cause shaving of plating when the press-fit terminal is inserted into the substrate, and improving a heat resistance, a post-treatment may be carried out. The post-treatment improves the lubricity, to thereby provide a further low inserting force, makes shaving of plating unlikely to be caused, and suppresses the oxidation of the A layer and the B layer, to thereby improve the durability such as a heat resistance and a gas corrosion resistance. The post-treatment specifically includes a phosphate salt treatment, a lubrication treatment, and a silane coupling treatment, using inhibitors. Here, the post-treatment is not limited.


Properties of Metal Material


The Vickers hardness as measured from the surface of the A layer 14 is preferably Hv100 or higher. With the Vickers hardness as measured from the surface of the A layer 14 of Hv100 or higher, the hard A layer improves the thin film lubrication effect and provides the low inserting force. By contrast, the Vickers hardness as measured from the surface of the A layer 14 is preferably Hv1,000 or lower. With the Vickers hardness as measured from the surface of the A layer 14 of Hv1,000 or lower, the bending workability is improved; and in the case where the press-fit terminal according to the present invention is press-formed, cracks are hardly generated in the formed portion, and the decrease in the gas corrosion resistance is suppressed.


The indentation hardness as measured from the surface of the A layer 14 is preferably 1,000 MPa or higher. Here, the indentation hardness as measured from the surface of the A layer 14 is a hardness acquired by measuring an impression made on the surface of the A layer by a load of 0.1 mN in an ultrafine hardness test. With the surface indentation hardness of the A layer 14 of 1,000 MPa or higher, the hard A layer improves the thin film lubrication effect and provides a low inserting force. By contrast, the Vickers indentation hardness as measured from the surface of the A layer 14 is preferably 10,000 MPa or lower. With the surface indentation hardness of the A layer 14 of 10,000 MPa or lower, the bending workability is improved; and in the case where the press-fit terminal according to the present invention is press-formed, cracks are hardly generated in the formed portion, and the decrease in the gas corrosion resistance is suppressed.


The arithmetic average height (Ra) of the surface of the A layer 14 is preferably 0.1 μm or lower. With the arithmetic average height (Ra) of the surface of the A layer 14 of 0.1 μm or lower, since convex portions, which are relatively easily corroded, become few and the surface becomes smooth, the gas corrosion resistance is improved.


The maximum height (Rz) of the surface of the A layer 14 is preferably 1 μm or lower. With the maximum height (Rz) of the surface of the A layer 14 of 1 μm or lower, since convex portions, which are relatively easily corroded, become few and the surface becomes smooth, the gas corrosion resistance is improved.


The surface reflection density of the A layer 14 is preferably 0.3 or higher. With the surface reflection density of the A layer 14 of 0.3 or higher, since convex portions, which are relatively easily corroded, become few and the surface becomes smooth, the gas corrosion resistance is improved.


The cross-section Vickers hardness of the C layer 12 is preferably Hv300 or higher. With the cross-section Vickers hardness of the C layer 12 of Hv300 or higher, the C layer is further hardened to thereby further improve the thin film lubrication effect to provide a low inserting force. By contrast, the cross-section Vickers hardness of the C layer 12 is preferably Hv1,000 or lower. With the cross-section Vickers hardness of the C layer 12 of Hv1,000 or lower, the bending workability is improved; and in the case where the press-fit terminal according to the present invention is press-formed, cracks are hardly generated in the formed portion, and the decrease in the gas corrosion resistance is suppressed.


The cross-section Vickers hardness of the C layer 12 and the thickness of the C layer 12 preferably satisfy the following expression:

Vickers hardness(Hv)≧−376.22 Ln(thickness:μm)+86.411.

If the cross-section Vickers hardness of the C layer 12 and the thickness of the C layer 12 satisfy the above expression, the C layer is further hardened to thereby further improve the thin film lubrication effect to provide the low inserting force.


Here, in the present invention, “Ln (thickness: μm)” refers to a numerical value of a natural logarithm of a thickness (μm).


The cross-section indentation hardness of the C layer 12 is preferably 2,500 MPa or higher. Here, the cross-section indentation hardness of the C layer 12 is a hardness acquired by measuring an impression made on the cross-section of the C layer 12 by a load of 0.1 mN in an ultrafine hardness test. With the cross-section indentation hardness of the C layer 12 of 2,500 MPa or higher, the C layer is further hardened to thereby further improve the thin film lubrication effect to provide the low inserting force. By contrast, the cross-section indentation hardness of the C layer 12 is preferably 10,000 MPa or lower. With the cross-section indentation hardness of the C layer 12 of 10,000 MPa or lower, the bending workability is improved; and in the case where the press-fit terminal according to the present invention is press-formed, cracks are hardly generated in the formed portion, and the decrease in the gas corrosion resistance is suppressed.


The cross-section indentation hardness of the C layer 12 and the thickness of the C layer 12 preferably satisfy the following expression:

Indentation hardness(MPa)≧−3998.4 Ln(thickness:μm)+1178.9.

If the cross-section indentation hardness of the C layer 12 and the thickness of the C layer 12 satisfy the above expression, the C layer is further hardened to thereby further improve the thin film lubrication effect to provide the low inserting force.


When a depth analysis by XPS (X-ray photoelectron spectroscopy) is carried out, it is preferable that a position (D1) where the atomic concentration (at %) of Sn or In of the A layer 14 is a maximum value, a position (D2) where the atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of the B layer 13 is a maximum value, and a position (D3) where the atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, or Cu of the C layer 12 is a maximum value are present in the order of D1, D2, and D3 from the outermost surface. If the positions are not present in the order of D1, D2, and D3 from the outermost surface, there arises a risk that: a sufficient gas corrosion resistance cannot be provided; and when the press-fit terminal is subjected to a gas corrosion test using chlorine gas, sulfurous acid gas, hydrogen sulfide gas, or the like, the press-fit terminal is corroded to thereby largely increase the contact resistance as compared with before the gas corrosion test.


When a depth analysis by XPS (X-ray photoelectron spectroscopy) is carried out, it is preferable that: the A layer 14 has a maximum value of an atomic concentration (at %) of Sn or In of 10 at % or higher, and the B layer 13 has a maximum value of an atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of 10 at % or higher; and a depth where the atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, or Cu of the C layer 12 is 25 at % or higher is 50 nm or more. In the case where the maximum value of the atomic concentration (at %) of Sn or In of the A layer 14, and the maximum value of the atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of the B layer 13 are each lower than 10 at %; and where a depth where the atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, or Cu of the C layer 12 is 25 at % or higher is shallower than 50 nm, there arises a risk that the inserting force is high, and the base material components diffuse to the A layer 14 or the B layer 13 to thereby worsen the heat resistance and the gas corrosion resistance.


When a depth analysis by XPS (X-ray photoelectron spectroscopy) is carried out, it is preferable that between a position (D1) where the atomic concentration (at %) of Sn or In of the A layer 14 is a maximum value and a position (D3) where the atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, Cu, or Zn of the C layer 12 is a maximum value, a region having 40 at % or more of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir is present in a thickness of 1 nm or larger. If the region is present in a thickness of smaller than 1 nm, for example, in the case of Ag, there arises a risk of worsening the heat resistance.


When an elemental analysis of the surface of the A layer is carried out by a survey measurement by XPS (X-ray photoelectron spectroscopy), it is preferable that the content of Sn, In is 2 at % or higher. If the content of Sn, In is lower than 2 at %, for example, in the case of Ag, there arises a risk that the sulfurization resistance is inferior and the contact resistance largely increases. For example, in the case of Pd, there arises a risk that Pd is oxidized to thereby raise the contact resistance.


When an elemental analysis of the surface of the A layer is carried out by a survey measurement by XPS (X-ray photoelectron spectroscopy), it is preferable that the content of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir is lower than 7 at %. If the content of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir is 7 at % or higher, for example, in the case of Ag, there arises a risk that the sulfurization resistance is inferior and the contact resistance largely increases. For example, in the case of Pd, there arises a risk that Pd is oxidized to thereby raise the contact resistance.


When an elemental analysis of the surface of the A layer is carried out by a survey measurement by XPS (X-ray photoelectron spectroscopy), it is preferable that the content of O is lower than 50 at %. If the content of O is 50 at % or higher, there arises a risk of raising the contact resistance.


Method for Manufacturing a Press-Fit Terminal


A method for manufacturing the press-fit terminal according to the present invention is not limited. The press-fit terminal can be manufactured by subjecting a base material previously formed into a press-fit terminal shape by press-forming or the like to wet (electro-, electroless) plating, dry (sputtering, ion plating, or the like) plating, or the like.


Examples

Hereinafter, although Examples of the present invention will be described with Comparative Examples, these are provided to better understand the present invention, and are not intended to limit the present invention.


As Examples and Comparative Examples, samples to be formed by providing a base material, a C layer, a B layer, and an A layer in this order, and possibly heat-treating the resultant, were each fabricated under the conditions shown in the following Tables 1 to 7.


Specifications of press-fit terminals and through-holes are shown in Table 1; the fabrication condition of C layers is shown in Table 2; the fabrication condition of B layers is shown in Table 3; the fabrication condition of A layers is shown in Table 4; and the heat treatment condition is shown in Table 5. The fabrication conditions and the heat treatment conditions of the each layer used in each Example are shown in Table 6; and the fabrication conditions and the heat treatment conditions of the each layer used in each Comparative Example are shown in Table 7.










TABLE 1





Specification of Press-Fit Terminal
Specification of Through-Hole







made by Tokiwa & Co., Inc., Press-fit
Thickness of substrate: 2 mm


terminal PCB connector, R800
through-hole: Φ 1 mm
















TABLE 2







Condition of Underlayers (C Layers)










Surface Treatment



No.
Method
Detail





1
Electroplating
Plating liquid: Ni sulfamate plating liquid




Plating temperature: 55° C.




Current density: 0.5 to 4 A/dm2


2
Electroplating
Plating liquid: Cu sulfate plating liquid




Plating temperature: 30° C.




Current density: 2.3 A/dm2


3
Electroplating
Plating liquid: chromium sulfate liquid




Plating temperature: 30° C.




Current density: 4 A/dm2


4
Sputtering
Target: having a predetermined composition




Apparatus: sputtering apparatus made by




Ulvac, Inc.




Output: DC 50 W




Argon pressure: 0.2 Pa


5
Electroplating
Plating liquid: Fe sulfate liquid




Plating temperature: 30° C.




Current density: 4 A/dm2


6
Electroplating
Plating liquid: Co sulfate bath




Plating temperature: 30° C.




Current density: 4 A/dm2


7
Electroplating
Plating liquid: Ni sulfamate plating




liquid + saccharin




Plating temperature: 55° C.




Current density: 4 A/dm2


8
Electroplating
Plating liquid: Ni sulfamate plating




liquid + saccharin + additive




Plating temperature: 55° C.




Current density: 4 A/dm2
















TABLE 3







Condition of Middle Layers (B Layers)










Surface Treatment



No.
Method
Detail





1
Electroplating
Plating liquid: Ag cyanide plating liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2


2
Electroplating
Plating liquid: Au cyanide plating liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2


3
Electroplating
Plating liquid: chloroplatinic acid plating




liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2


4
Electroplating
Plating liquid: diammine palladium (II)




chloride plating liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2


5
Electroplating
Plating liquid: Ru sulfate plating liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2


6
Sputtering
Target: having a predetermined composition




Apparatus: sputtering apparatus made by




Ulvac, Inc.




Output: DC 50 W




Argon pressure: 0.2 Pa


7
Electroplating
Plating liquid: Sn methanesulfonate plating




liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2


8
Electroplating
Plating liquid: Cu sulfate plating liquid




Plating temperature: 30° C.




Current density: 2.3 A/dm2
















TABLE 4







Condition of Base Material of Outermost


Surface Layers (A Layers)










Surface Treatment



No.
Method
Detail





1
Electroplating
Plating liquid: Sn methanesulfonate plating




liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2


2
Sputtering
Target: having a predetermined composition




Apparatus: sputtering apparatus made by




Ulvac, Inc.




Output: DC 50 W




Argon pressure: 0.2 Pa


3
Electroplating
Plating liquid: Ag cyanide plating liquid




Plating temperature: 40° C.




Current density: 0.2 to 4 A/dm2
















TABLE 5







Heat Treatment Condition










Temperature
Time


No.
[° C.]
[second]












1
300
5


2
300
20 


3
30
12 hours


4
50
12 hours


5
50
20 hours


6
300
3


7
500
1


8
600
1




















TABLE 6






Outermost






Surface Layer
Middle Layer
Underlayer
Heat



(A Layer)
(B Layer)
(C Layer)
Treatment



Condition
Condition
Condition
Condition


Example
No. see
No. see
No. see
No. see


No.
Table 4
Table 3
Table 2
Table 5



















1
1
1
1



2
1
1
1



3
1
1
1



4
1
1
1



5
1
1
1



6
2
1
1



7
2
1
1



8
2
1
1



9
2
1
1



10
2
1
1



11
2
1
1



12
2
1
1



13
2
1
1



14
2
1
1



15
2
1
1



16
2
1
1



17
2
1
1



18
2
1
1



19
2
1
1



20
2
1
1



21
2
1
1



22
2
1
1



23
2
1
1



24
1
2
1



25
1
3
1



26
1
4
1



27
1
5
1



28
1
6
1



29
1
6
1



30
1
6
1



31
1
6
1



32
1
6
1



33
1
6
1



34
1
6
1



35
1
6
1



36
1
6
1



37
1
6
1



38
1
6
1



39
1
6
1



40
1
6
1



41
1
6
1



42
1
6
1



43
1
6
1



44
1
6
1



45
1
6
1



46
1
6
1



47
1
6
1



48
1
6
1



49
1
6
1



50
1
6
1



51
1
6
1



52
1
6
1



53
1
1
3



54
1
1
4



55
1
1
5



56
1
1
6



57
1
1
2



58
1
1
4



59
1
1
4



60
1
1
4



61
1
1
4



62
1
1
4



63
1
1
4



64
1
1
4



65
1
1
4



66
1
1
4



67
1
1
1



68
1
1
7



69
1
1
8



70
1
1
1



71
1
1
1



72
1
1
1



73
1
1
1



74
1
1
1



75
1
1
1



76
1
1
1



77
1
1
1



78
1
1
1



79
1
1
1



80
1
1
1



81
1
1
7



82
1
1
8



83
1
1
7



84
1
1
7



85
1
1
8



86
1
1
8



87
1
1
4



88
1
1
4



89
1
1
1
1


90
1
1
1
2


91
1
2
1



92
1
2
1



93
2
1
1



94
2
1
1



95
1
1
1



96
1
1
1
3


97
1
1
1
4


98
1
1
1
5


99
1
1
1
6


100
1
1
1
7


101
1
1
1
8




















TABLE 7






Outermost






Surface Layer
Middle Layer
Underlayer
Heat



(A Layer)
(B Layer)
(C Layer)
Treatment



Condition
Condition
Condition
Condition


Comparative
No. see
No. see
No. see
No. see


Example No.
Table 4
Table 3
Table 2
Table 5



















1
1

1
1


2
1

1
1


3
1

1



4
1
8
1
1


5
1
8
1
1


6
1
8
1



7
1

2
1


8
1

1
1


9
1
1
1



10
1
1
1



11
1
1
1



12
1

1



13
1
1
1



14
1

1



15
1
1
1



16
1
1
1



17
3
7
1



18
1
1
1



19
1

1










Measurement of a Thickness


The thicknesses of an A layer, a B layer, and a C layer were measured by carrying out the each surface treatment on a base material, and measuring respective actual thicknesses by an X-ray fluorescent film thickness meter (made by Seiko Instruments Inc., SEA5100, collimator: 0.1 mmφ).


Measurement of a Deposition Amount


Each sample was acidolyzed with sulfuric acid, nitric acid, or the like, and measured for a deposition amount of each metal by ICP (inductively coupled plasma) atomic emission spectroscopy. The acid to be specifically used depends on the composition of the each sample.


Determination of a Composition


The composition of each metal was calculated based on the measured deposition amount.


Determination of a Layer Structure


The layer structure of the obtained sample was determined by a depth profile by XPS (X-ray photoelectron spectroscopy) analysis. The analyzed elements are compositions of an A layer, a B layer, and a C layer, and C and O. These elements are made as designated elements. With the total of the designated elements being taken to be 100%, the concentration (at %) of the each element was analyzed. The thickness by the XPS (X-ray photoelectron spectroscopy) analysis corresponds to a distance (in terms of SiO2) on the abscissa of the chart by the analysis.


The surface of the obtained sample was also subjected to a qualitative analysis by a survey measurement by XPS (X-ray photoelectron spectroscopy) analysis. The resolution of the concentration by the qualitative analysis was set at 0.1 at %.


An XPS apparatus to be used was 5600MC, made by Ulvac-Phi, Inc., and the measurement was carried out under the conditions of ultimate vacuum: 5.7×10−9 Torr, exciting source: monochromated AlKα, output: 210 W, detection area: 800 μmφ, incident angle: 45°, takeoff angle: 45°, and no neutralizing gun, and under the following sputtering condition.


Ion species: Ar+


Acceleration voltage: 3 kV


Sweep region: 3 mm×3 mm


Rate: 2.8 nm/min (in terms of SiO2)


Evaluations


Each sample was evaluated for the following items.


A. Inserting Force


The inserting force was evaluated by measuring an inserting force when a press-fit terminal was inserted into a substrate. A measurement apparatus used in the test was 1311NR, made by Aikoh Engineering Co., Ltd. The press-fit terminal was slid for the test in a state where the substrate was fixed. The number of the samples was set to be five; and a value obtained by averaging the values of the maximum inserting forces of the samples was employed as the inserting force. Samples of Comparative Example 1 were employed as a blank material for the inserting force.


The target of the inserting force was lower than 85% of the maximum inserting force of Comparative Example 1. Because Comparative Example 4 having an inserting force of 90% of the maximum inserting force of Comparative Example 1 was present as an actual product, the inserting force lower than 85% of the maximum inserting force of Comparative Example 1 and lower than that in Comparative Example 4 by 5% or more was targeted.


B. Whisker


The press-fit terminal was inserted into the through-hole of the substrate by a hand press, and a thermal shock cycle test (JEITA ET-7410) was carried out. The sample whose test had been finished was observed at a magnification of 100 to 10,000 times by a SEM (made by JEOL Ltd., type: JSM-5410) to observe the generation situation of whiskers.


Thermal Shock Cycle Test

Low temperature−40° C.×30 minutes⇄high temperature 85° C.×30 minutes/cycle×1000 cycles


The target property was that no whiskers of 20 μm or longer in length were generated, but the top target was that no whisker at all was generated.


C. Contact Resistance


The contact resistance was measured using a contact simulator CRS-113-Au, made by Yamasaki-Seiki Co., Ltd., by a four-terminal method under the condition of a contact load of 50 g. The number of the samples was made to be five, and a range of from the minimum value to the maximum value of the samples was employed. The target property was a contact resistance of 10 mΩ or lower. The contact resistance was classified into 1 to 3 mΩ, 3 to 5 mΩ, and higher than 5 mΩ.


D. Heat Resistance


The heat resistance was evaluated by measuring the contact resistance of a sample after an atmospheric heating (175° C.×500 h) test. The target property was a contact resistance of 10 mΩ or lower, but the top target was made to be no variation (being equal) in the contact resistance before and after the heat resistance test. The heat resistance was classified into 1 to 4 mΩ, 2 to 4 mΩ, 2 to 5 mΩ, 3 to 6 mΩ, 3 to 7 mΩ, 6 to 9 mΩ, and higher than 10 mΩ in terms of contact resistance.


E. Gas Corrosion Resistance


The gas corrosion resistance was evaluated by three test environments shown in (1) to (3) described below. The evaluation of the gas corrosion resistance was carried out by using the contact resistance of a sample after the environment tests of (1) to (3). The target property was a contact resistance of 10 mΩ or lower, but the top target was made to be no variation (being equal) in the contact resistance before and after the gas corrosion resistance test. The gas corrosion resistance was classified into 1 to 3 mΩ, 1 to 4 mΩ, 2 to 4 mΩ, 2 to 6 mΩ, 3 to 5 mΩ, 3 to 7 mΩ, 4 to 7 mΩ, 5 to 8 mΩ, 6 to 9 mΩ, and higher than 10 mΩ in terms of contact resistance.

    • (1) Salt spray test
    • Salt concentration: 5%
    • Temperature: 35° C.
    • Spray pressure: 98±10 kPa
    • Exposure time: 96 h
    • (2) Sulfurous acid gas corrosion test
    • Sulfurous acid concentration: 25 ppm
    • Temperature: 40° C.
    • Humidity: 80% RH
    • Exposure time: 96 h
    • (3) Hydrogen sulfide gas corrosion test
    • Sulfurous acid concentration: 10 ppm
    • Temperature: 40° C.
    • Humidity: 80% RH
    • Exposure time: 96 h


G. Bending workability


The bending workability was evaluated by a 90° bending of a sample under the condition that the ratio of the thickness and the bending radius of the sample became 1 by using a letter-W-shape die. The evaluation was made as good in the case where no crack was observed in the observation of the surface of the bending-worked portion by an optical microscope, posing no practical problem; and as poor in the case where any cracks were observed therein.


H. Vickers Hardness


The Vickers hardnesses of an A layer and a C layer were measured by making an impression by a load of 980.7 mN (Hv0.1) from the surface of the A layer and the cross-section of the C layer in a load retention time of 15 sec.


I. Indentation Hardness


The indentation hardnesses of an A layer and a C layer were measured by making an impression on the surface of the A layer and the cross-section of the C layer at a load of 0.1 mN by an ultrafine hardness tester (ENT-2100, made by Elionix Inc.).


J. Surface Roughness


The surface roughnesses (arithmetic average height (Ra) and maximum height (Rz)) were measured according to JIS B 0601 by using a non-contact type three dimensional measurement instrument (made by Mitaka Kohki Co., Ltd., type: NH-3). The measurement was carried out five times per sample, with a cutoff of 0.25 mm and a measurement length of 1.50 mm.


K. Reflection Density


The reflection density was measured using a densitometer (ND-1, made by Nippon Denshoku Industries Co., Ltd.).


L. Generation of Powder


The press-fit terminal inserted into the through-hole was extracted from the through-hole, and the cross-section of the press-fit terminal was observed at a magnification of 100 to 10,000 times by a SEM (made by JEOL Ltd., type: JSM-5410) to observe the generation status of powder. The press-fit terminal with which the diameter of the powder was smaller than 5 μm was made as good; the press-fit terminal with which the diameter of the powder was 5 to smaller than 10 μm was made as average; and the press-fit terminal with which the diameter of the powder was 10 μm or larger was made as poor.


The respective conditions and evaluation results are shown in Tables 8 to 22.














TABLE 8









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition
Heat




Thickness
Amount

Thickness
Amount

Thickness
Amount
Treatment



Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]
Condition






















Example
1
Sn
0.2
146 
Ag
0.3
315 
Ni
1.0
0.9
None



2
Sn
0.2
146 
Ag
0.001
 1
Ni
1.0
0.9
None



3
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



4
Sn
0.002
 1
Ag
0.3
315 
Ni
1.0
0.9
None



5
Sn
0.002
 1
Ag
0.001
 1
Ni
1.0
0.9
None



6
In
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



7
Sn—2Ag
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



8
Sn—2As
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



9
Sn—2Au
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



10
Sn—2Bi
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



11
Sn—2Cd
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



12
Sn—2Co
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



13
Sn—2Cr
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



14
Sn—2Cu
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



15
Sn—2Fe
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



16
Sn—2In
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



17
Sn—2Mn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



18
Sn—2Mo
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



19
Sn—2Ni
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



20
Sn—2Pb
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



21
Sn—2Sb
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



22
Sn—2W
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



23
Sn—2Zn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



24
Sn
0.03
22
Au
0.03
32
Ni
1.0
0.9
None



25
Sn
0.03
22
Pt
0.03
32
Ni
1.0
0.9
None



26
Sn
0.03
22
Pd
0.03
32
Ni
1.0
0.9
None



27
Sn
0.03
22
Ru
0.03
32
Ni
1.0
0.9
None



28
Sn
0.03
22
Rh
0.03
32
Ni
1.0
0.9
None



29
Sn
0.03
22
Os
0.03
32
Ni
1.0
0.9
None



30
Sn
0.03
22
Ir
0.03
32
Ni
1.0
0.9
None



31
Sn
0.03
22
Ag—2Au
0.03
32
Ni
1.0
0.9
None



32
Sn
0.03
22
Ag—2Bi
0.03
32
Ni
1.0
0.9
None



33
Sn
0.03
22
Ag—2Cd
0.03
32
Ni
1.0
0.9
None



34
Sn
0.03
22
Ag—2Co
0.03
32
Ni
1.0
0.9
None



35
Sn
0.03
22
Ag—2Cu
0.03
32
Ni
1.0
0.9
None



36
Sn
0.03
22
Ag—2Fe
0.03
32
Ni
1.0
0.9
None



37
Sn
0.03
22
Ag—2In
0.03
32
Ni
1.0
0.9
None



38
Sn
0.03
22
Ag—2Ir
0.03
32
Ni
1.0
0.9
None



39
Sn
0.03
22
Ag—2Mn
0.03
32
Ni
1.0
0.9
None

















Target

0.002≦
  1≦

0.001≦
  1≦

0.005≦
0.03≦





≦0.2
≦150  

≦0.3
≦330  





















TABLE 9









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition
Heat




Thickness
Amount

Thickness
Amount

Thickness
Amount
Treatment



Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]
Condition






















Example
40
Sn
0.03
22
Ag—2Mo
0.03
32
Ni
1.0
0.9
None



41
Sn
0.03
22
Ag—2Ni
0.03
32
Ni
1.0
0.9
None



42
Sn
0.03
22
Ag—2Pb
0.03
32
Ni
1.0
0.9
None



43
Sn
0.03
22
Ag—2Pd
0.03
32
Ni
1.0
0.9
None



44
Sn
0.03
22
Ag—2Pt
0.03
32
Ni
1.0
0.9
None



45
Sn
0.03
22
Ag—2Rh
0.03
32
Ni
1.0
0.9
None



46
Sn
0.03
22
Ag—2Ru
0.03
32
Ni
1.0
0.9
None



47
Sn
0.03
22
Ag—2Sb
0.03
32
Ni
1.0
0.9
None



48
Sn
0.03
22
Ag—2Se
0.03
32
Ni
1.0
0.9
None



49
Sn
0.03
22
Ag—2Sn
0.03
32
Ni
1.0
0.9
None



50
Sn
0.03
22
Ag—2W
0.03
32
Ni
1.0
0.9
None



51
Sn
0.03
22
Ag—2TI
0.03
32
Ni
1.0
0.9
None



52
Sn
0.03
22
Ag—2Zn
0.03
32
Ni
1.0
0.9
None


Com-
1
Sn
1.0
728 



Ni
0.5
0.4
300° C. × 5 sec.


parative
2
Sn
0.6
437 



Ni
0.5
0.4
300° C. × 5 sec.


Example
3
Sn
0.6
437 



Ni
0.5
0.4



4
Sn
0.6
437 
Cu
0.3

Ni
0.5
0.4
300° C. × 5 sec.



5
Sn
0.4
291 
Cu
0.3

Ni
0.5
0.4
300° C. × 5 sec.



6
Sn
0.4
291 
Cu
0.3

Ni
0.5
0.4



7
Sn
1.0
728 



Cu
0.5
0.4
300° C. × 5 sec.



8
Sn
1.0
728 



Ni
1.0
0.9
300° C. × 5 sec.



9
Sn
0.3
218 
Ag
0.3
315 
Ni
1.0
0.9
None



10
Sn
0.3
218 
Ag
0.001
  1.1
Ni
1.0
0.9
None



11
Sn
0.2
146 
Ag
0.5
525 
Ni
1.0
0.9
None



12
Sn
0.2
146 
Ag


Ni
1.0
0.9
None



13
Sn
0.002
  1.5
Ag
0.5
525 
Ni
1.0
0.9
None



14
Sn
0.002
  1.5
Ag


Ni
1.0
0.9
None



15
Sn
0.001
  0.7
Ag
0.3
315 
Ni
1.0
0.9
None



16
Sn
0.001
  0.7
Ag
0.001
  1.1
Ni
1.0
0.9
None



17
Ag
0.03
32
Sn
0.03
22
Ni
1.0
0.9
None

















Target

0.002≦
  1≦

0.001≦
  1≦

0.005≦
0.03≦





≦0.2
≦150  

≦0.3
≦330  



















TABLE 10









Whisker
















Number









of
Number
Inserting Force



Whisker
of
Maximum



of
Whiskers
Inserting


Gas Corrosion Resistance

















Shorter
of 20 μm
Force/Maximum

Heat

Sulfurous
Hydrogen




Than 20 μm
or
Inserting Force

Resistance
Salt Spray
Acid Gas
Sulfide



in
Longer in
of Comparative
Contact
Contact
Contact
Contact
Contact
Generation



Length
Length
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance
Situation



[Number]
[Number]
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
of Powder





















Example
1
0
0
82
1-3
1-4
1-4
1-4
1-4
Average



2
0
0
79
1-3
6-9
1-4
1-4
1-4
Average



3
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



4
0
0
79
1-3
1-4
4-7
5-8
6-9
Average



5
0
0
76
1-3
6-9
4-7
5-8
6-9
Good



6
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



7
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



8
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



9
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



10
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



11
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



12
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



13
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



14
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



15
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



16
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



17
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



18
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



19
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



20
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



21
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



22
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



23
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



24
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



25
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



26
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



27
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



28
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



29
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



30
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



31
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



32
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



33
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



34
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



35
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



36
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



37
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



38
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



39
0
0
77
1-3
1-4
1-4
1-4
1-4
Good
















Target

0
<85
≦10
≦10
≦10
≦10
≦10
Average











or higher



















TABLE 11









Whisker
















Number
Inserting Force







of
Maximum



Number
Whiskers
Inserting

Gas Corrosion Resistance



















of Whiskers of
of 20 μm
Force/Maximum

Heat

Sulfurous
Hydrogen





Shorter Than
or
Inserting Force

Resistance
Salt Spray
Acid Gas
Sulfide




20 μm in
Longer in
of Comparative
Contact
Contact
Contact
Contact
Contact
Generation




Length
Length
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance
Situation




[Number]
[Number]
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
of Powder




















Example
40
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



41
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



42
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



43
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



44
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



45
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



46
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



47
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



48
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



49
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



50
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



51
0
0
77
1-3
1-4
1-4
1-4
1-4
Good



52
0
0
77
1-3
1-4
1-4
1-4
1-4
Good


Comparative Example
1

≦3

1-3
3-7
1-3
1-3
1-3
Poor



2

≦3

1-3




Poor



3

≦3
120
1-3




Poor



4

≦3
90
1-3
3-7
1-3
1-3
1-3
Poor



5

≦2

1-3




Poor



6

≦2
105
1-3




Poor



7

≦3
100
1-3
3-7
1-3
1-3
1-3
Poor



8

≦3
100
1-3
3-7
1-3
1-3
1-3
Poor



9
1-5
0
84
1-3




Poor



10
1-5
0
81
1-3




Average



11



1-3




Poor



12



1-3
10<



Average



13



1-3




Poor



14



1-3
10<



Good



15



1-3



10<
Average



16



1-3



10<
Good



17



1-3



10<
Good
















Target

0
<85
≦10
≦10  
≦10
≦10
≦10  
Average











or higher




















TABLE 12









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition





Thickness
Amount

Thickness
Amount

Thickness
Amount




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]





Example
53
Sn
0.03
22
Ag
0.03
32
Cr
1.0
0.9



54
Sn
0.03
22
Ag
0.03
32
Mn
1.0
0.9



55
Sn
0.03
22
Ag
0.03
32
Fe
1.0
0.9



56
Sn
0.03
22
Ag
0.03
32
Co
1.0
0.9



57
Sn
0.03
22
Ag
0.03
32
Cu
1.0
0.9



58
Sn
0.03
22
Ag
0.03
32
Ni—Cr
1.0
0.9



59
Sn
0.03
22
Ag
0.03
32
Ni—Mn
1.0
0.9



60
Sn
0.03
22
Ag
0.03
32
Ni—Fe
1.0
0.9



61
Sn
0.03
22
Ag
0.03
32
Ni—Co
1.0
0.9



62
Sn
0.03
22
Ag
0.03
32
Ni—Cu
1.0
0.9



63
Sn
0.03
22
Ag
0.03
32
Ni—B
1.0
0.9



64
Sn
0.03
22
Ag
0.03
32
Ni—P
1.0
0.9



65
Sn
0.03
22
Ag
0.03
32
Ni—Sn
1.0
0.9



66
Sn
0.03
22
Ag
0.03
32
Ni—Zn
1.0
0.9



67
Sn
0.03
22
Ag
0.03
32
Ni
0.1
0.1


Comparative
18
Sn
0.03
22
Ag
0.03
32
Ni
0.01
0.01


Example
















Target

0.002≦
    1≦

0.001≦
    1≦

0.005≦
0.03≦




≦0.2
≦150    

≦0.3
≦330    















Inserting Force






Maximum



Inserting

Gas Corrosion Resistance





















Force/Maximum

Heat

Sulfurous
Hydrogen







Inserting Force

Resistance
Salt Spray
Acid Gas
Sulfide





Heat
of Comparative
Contact
Contact
Contact
Contact
Contact
Generation





Treatment
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance
Situation





Condition
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
of Powder







Example
53
None
66
1-3
1-4
1-4
1-4
1-4
Good




54
None
80
1-3
1-4
1-4
1-4
1-4
Good




55
None
77
1-3
1-4
1-4
1-4
1-4
Good




56
None
75
1-3
1-4
1-4
1-4
1-4
Good




57
None
79
1-3
1-4
1-4
1-4
1-4
Good




58
None
71
1-3
1-4
1-4
1-4
1-4
Good




59
None
79
1-3
1-4
1-4
1-4
1-4
Good




60
None
77
1-3
1-4
1-4
1-4
1-4
Good




61
None
73
1-3
1-4
1-4
1-4
1-4
Good




62
None
77
1-3
1-4
1-4
1-4
1-4
Good




63
None
66
1-3
1-4
1-4
1-4
1-4
Good




64
None
66
1-3
1-4
1-4
1-4
1-4
Good




65
None
75
1-3
1-4
1-4
1-4
1-4
Good




66
None
77
1-3
1-4
1-4
1-4
1-4
Good




67
None
80
1-3
1-4
1-4
1-4
1-4
Good



Comparative
18
None
89
1-3
  10<
2-4
2-4
2-4




Example

















Target

<85
≦10
≦10
≦10
≦10
≦10
Average











or higher





















TABLE 13









A Layer
B Layer




















Deposition


Deposition






Thickness
Amount

Thickness
Amount
C Layer




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition





Example
1
Sn
0.2
146
Ag
0.3
315
Ni



68
Sn
0.2
146
Ag
0.3
315
Ni (semi-










bright)



69
Sn
0.2
146
Ag
0.3
315
Ni (bright)



64
Sn
0.2
146
Ag
0.3
315
Ni—P














Target

0.002≦
   1≦

0.001≦
   1≦





≦0.2
≦150  

≦0.3
≦330  

















Inserting






Force





Maximum





Inserting





Force/





Maximum





Inserting



C Layer

Force of


















Deposition
Heat
Vickers
Indentation
Comparative





Thickness
Amount
Treatment
Hardness
Hardness
Example 1
Bending




[μm]
[mg/cm2]
Condition
Hv
[MPa]
[%]
Workability





Example
1
1.0
0.9
None
130
1500
82
Good



68
1.0
0.9
None
300
3400
78
Good



69
1.0
0.9
None
600
6700
72
Good



64
1.0
0.9
None
1200
13000
66
Poor












Target
0.005≦
0.03≦

<85




















TABLE 14









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition





Thickness
Amount

Thickness
Amount

Thickness
Amount




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]





Example
1
Sn
0.2 (Dk =
146
Ag
0.3 (Dk = 0.5)
315
Ni
1.0
0.9





0.5)



70
Sn
0.2 (Dk =
146
Ag
0.3 (Dk = 4)
315
Ni
1.0
0.9





0.5)



71
Sn
0.2 (Dk = 4)
146
Ag
0.3 (Dk = 0.5)
315
Ni
1.0
0.9



72
Sn
0.2 (Dk = 4)
146
Ag
0.3 (Dk = 45)
315
Ni
1.0
0.9
















Target

   0.002≦
    1≦

   0.001≦
    1≦

0.005≦
0.03≦




≦0.2
≦150   

≦0.3
≦330  














Evaluation from Outermost





Surface Layer

Gas Corrosion Resistance






















Arithmetic



Heat

Sulfurous
Hydrogen






Average
Maximum


Resistance
Salt Spray
Acid Gas
Sulfide





Heat
Height
Height

Contact
Contact
Contact
Contact
Contact





Treatment
Ra
Rz
Reflection
Resistance
Resistance
Resistance
Resistance
Resistance





Condition
[μm]
[μm]
Density
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]







Example
1
None
0.12
1.25
0.2
1-3
2-4
2-4
2-4
2-4




70
None
0.087
0.75
0.3
1-3
2-4
1-3
1-3
1-3




71
None
0.075
0.55
0.7
1-3
2-4
1-3
1-3
1-3




72
None
0.045
0.35
0.9
1-3
2-4
1-3
1-3
1-3


















Target




≦10
≦10
≦10
≦10
≦10






















TABLE 15









A Layer
B Layer
C Layer























Deposition


Deposition


Deposition
Heat






Amount

Thickness
Amount

Thickness
Amount
Treatment




Composition
Thickness [μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]
Condition





Example
3
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



67
Sn
0.03
22
Ag
0.03
32
Ni
0.1
0.1
None


Comparative
18
Sn
0.03
22
Ag
0.03
32
Ni
0.01
0.01
None


Example
17
Ag
0.03
22
Sn
0.03
32
Ni
1.0
0.89
None



14
Sn
0.002
  1.5



Ni
1.0
0.89
None



16
Sn
0.001
  0.7
Ag
0.001
  1.1
Ni
1.0
0.89
None

















Target

0.002≦
    1≦

0.001≦
    1≦

0.005≦
0.03≦





≦0.2
≦150    

≦0.3
≦330    
















Inserting Force






Maximum




Inserting



XPS (Depth)
Force/Maximum

Gas Corrosion Resistance

























D3
Inserting

Heat

Sulfurous
Hydrogen








Thickness
Force of

Resistance
Salt Spray
Acid Gas
Sulfide








of 25%
Comparative
Contact
Contact
Contact
Contact
Contact





Order of D1,
D1
D2
or More
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance





D2, and D3
[at %]
[at %]
[nm]
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]







Example
3
D1custom character  D2custom character  D3
35
35
100<
77
1-3
1-4
1-4
1-4
1-4




67
D1custom character  D2custom character  D3
87
87
80
80
1-3
1-4
1-4
1-4
1-4



Comparative
18
D1custom character  D2custom character  D3
87
87
25
89
1-3
<10
2-4
2-4
2-4



Example
17
D2custom character  D1custom character  D3




1-3



<10




14
D1custom character  D3
12
<10
100<

1-3
<10




16
D1custom character  D2custom character  D3
<10
14
100<

1-3



<10
















Target

<85
≦10
≦10
≦10
≦10
≦10






















TABLE 16









A Layer
B Layer
C Layer























Deposition


Deposition


Deposition
Heat






Amount

Thickness
Amount

Thickness
Amount
Treatment




Composition
Thickness [μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]
Condition





Example
3
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



73
Sn
0.01
 7
Ag
0.03
32
Ni
1.0
0.9
None



74
Sn
0.005
 4
Ag
0.03
32
Ni
1.0
0.9
None



75
Sn
0.1
73
Ag
0.03
32
Ni
1.0
0.9
None



76
Sn
0.2
146 
Ag
0.03
32
Ni
1.0
0.9
None

















Target

0.002≦
    1≦

0.001≦
    1≦

0.005≦
0.03≦





≦0.2
≦150    

≦0.3
≦330    













Whisker















Number








of
Number
Inserting Force



Whiskers
of
Maximum



of
Whiskers
Inserting

Gas Corrosion Resistance





















Shorter
of 20 μm
Force/Maximum

Heat

Sulfurous
Hydrogen






Than
or
Inserting Force

Resistance
Salt Spray
Acid Gas
Sulfide





20 μm in
Longer in
of Comparative
Contact
Contact
Contact
Contact
Contact
Generation





Length
Length
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance
Situation





[Number]
[Number]
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
of Powder







Example
3
0
0
77
1-3
1-4
1-4
1-4
1-4
Good




73
0
0
75
1-3
1-4
1-4
1-4
1-4
Good




74
0
0
74
1-3
1-4
2-6
3-7
4-7
Good




75
0
0
79
1-3
1-4
1-4
1-4
1-4
Good




76
0
0
83
1-3
1-4
1-4
1-4
1-4
Average


















Target

0
<85
≦10
≦10
≦10
≦10
≦10
Average












or higher





















TABLE 17









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition





Thickness
Amount

Thickness
Amount

Thickness
Amount




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]





Example
3
Sn
0.03
22
Ag
0.03
 32
Ni
1.0
0.9



77
Sn
0.03
22
Ag
0.001
   1.1
Ni
1.0
0.89



78
Sn
0.03
22
Ag
0.007
   7.4
Ni
1.0
0.89



79
Sn
0.03
22
Ag
0.1
105
Ni
1.0
0.89



80
Sn
0.03
22
Ag
0.3
315
Ni
1.0
0.89
















Target

0.002≦
    1≦

0.001≦
    1≦

0.005≦
0.03≦




≦0.2
≦150   

≦0.3
≦330    















Inserting Force






Maximum



Inserting

Gas Corrosion Resistance





















Force/Maximum

Heat

Sulfurous
Hydrogen







Inserting Force

Resistance
Salt Spray
Acid Gas
Sulfide





Heat
of Comparative
Contact
Contact
Contact
Contact
Contact
Generation





Treatment
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance
Situation





Condition
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
of Powder







Example
3
None
77
1-3
1-4
1-4
1-4
1-4
Good




77
None
73
1-3
6-9
1-4
1-4
1-4
Good




78
None
74
1-3
2-5
1-4
1-4
1-4
Good




79
None
78
1-3
1-4
1-4
1-4
1-4
Good




80
None
84
1-3
1-3
1-4
1-4
1-4
Average

















Target

<85 
≦10
≦10
≦10
≦10
≦10
Average











or higher





















TABLE 18









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition





Thickness
Amount

Thickness
Amount

Thickness
Amount




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]





Example
3
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9



81
Sn
0.03
22
Ag
0.03
32
Ni (semi-
1.0
0.9










bright)



82
Sn
0.03
22
Ag
0.03
32
Ni (bright)
1.0
0.9



64
Sn
0.03
22
Ag
0.03
32
Ni—P
1.0
0.9



83
Sn
0.03
22
Ag
0.03
32
Ni (semi-
0.8
0.7










bright)



84
Sn
0.03
22
Ag
0.03
32
Ni (semi-
0.5
0.4










bright)



85
Sn
0.03
22
Ag
0.03
32
Ni (bright)
0.6
0.5



86
Sn
0.03
22
Ag
0.03
32
Ni (bright)
0.3
0.3



87
Sn
0.03
22
Ag
0.03
32
Ni—P
0.2
0.2



88
Sn
0.03
22
Ag
0.03
32
Ni—P
0.05
0.04
















Target

0.002≦
    1≦

0.001≦
    1≦

0.005≦
0.03≦




≦0.2
≦150    

≦0.3
≦330    

















Inserting Force




C Layer

Maximum













Vickers Hardness
Indentation Hardness

Inserting



















Correlation between

Correlation between

Force/Maximum






Vickers Hardness and

Indentation Hardness

Inserting Force of





Expression

and Expression
Heat
Comparative
Generation





Expression: −376.22Ln

Expression: −3998.4Ln
Treatment
Example 1
Situation




Hv
(thickness) + 86.411
[MPa]
(thickness) + 1178.9
Condition
[%]
of Powder





Example
3
130
 86.4
1500
1178.9
None
77
Good






custom character  Vickers



custom character  Indentation






Hardness ≧ Expression

Hardness ≧ Expression



81
300
 86.4
3400
1178.9
None
74
Good






custom character  Vickers



custom character  Indentation






Hardness ≧ Expression

Hardness ≧ Expression



82
500
 86.4
5500
1178.9
None
70
Good






custom character  Vickers



custom character  Indentation






Hardness ≧ Expression

Hardness ≧ Expression



64
1200
 86.4
13000
1178.9
None
66
Good






custom character  Vickers



custom character  Indentation






Hardness ≧ Expression

Hardness ≧ Expression



83
300
170.4
3400
2071.1
None
75
Good






custom character  Vickers



custom character  Indentation






Hardness ≧ Expression

Hardness ≧ Expression



84
300
347.2
3400
3950.4
None
79
Good






custom character  Vickers



custom character  Indentation






Hardness < Expression

Hardness < Expression



85
500
278.6
5500
3221.4
None
76
Good






custom character  Vickers



custom character  Indentation






Hardness ≧ Expression

Hardness ≧ Expression



86
500
539.4
5500
5992.9
None
81
Good






custom character  Vickers



custom character  Indentation






Hardness < Expression

Hardness < Expression



87
1200
691.9
13000
7614.1
None
76
Good






custom character  Vickers



custom character  Indentation






Hardness ≧ Expression

Hardness ≧ Expression



88
1200
1213.5 
13000
13157.0 
None
83
Good






custom character  Vickers



custom character  Indentation






Hardness < Expression

Hardness < Expression










Target

<85
Average





or higher




















TABLE 19









A Layer
B Layer




















Deposition


Deposition






Thickness
Amount

Thickness
Amount
C Layer




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition





Example
3
Sn
0.03
22
Ag
0.03
32
Ni



81
Sn
0.03
22
Ag
0.03
32
Ni (semi-bright)



82
Sn
0.03
22
Ag
0.03
32
Ni (bright)



64
Sn
0.03
22
Ag
0.03
32
Ni—P














Target

0.002≦
    1≦

0.001≦
    1≦





≦0.2
≦150    

≦0.3
≦330    













C Layer




















Deposition
Vickers
Indentation
Heat






Thickness
Amount
Hardness
Hardness
Treatment
Bending





[μm]
[mg/cm2]
Hv
[MPa]
Condition
Workability







Example
3
1.0
0.9
130
1500
None
Good




81
1.0
0.9
300
3400
None
Good




82
1.0
0.9
600
6700
None
Good




64
1.0
0.9
1200
13000
None
Poor












Target
0.005≦
0.03≦






















TABLE 20









A Layer
B Layer
C Layer























Deposition


Deposition


Deposition
Heat





Thickness
Amount

Thickness
Amount

Thickness
Amount
Treatment




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]
Condition





Example
3
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
None



77
Sn
0.03
22
Ag
0.001
  1.1
Ni
1.0
0.9
None



5
Sn
0.002
 2
Ag
0.001
  1.1
Ni
1.0
0.9
None



89
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
300° C. ×













5 sec.



90
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
300° C. ×













20 sec.


Comparative
16
Sn
0.001
  0.7
Ag
0.001
  1.1
Ni
1.0
0.9
None


Example
19
Sn
0.03
22



Ni
1.0
0.9
None

















Target

0.002≦
1≦

0.001≦
1≦

0.005≦
0.03≦





≦0.2
≦150 

≦0.3
≦330 














XPS (Depth)





Thickness of



(Region)



Having a



Concentration
XPS (Survey)













of Ag, Au, Pt,

Concentration





Pd, Ru, Rh,

of Ag, Au, Pt,

Gas Corrosion Resistance





















Os, Ir of 40
Concentration
Pd, Ru, Rh,
Concentration

Heat

Sulfurous
Hydrogen





at % or higher
of Sn, In of
Os, Ir of
of O of

Resistance
Salt Spray
Acid Gas
Sulfide





between D1
Outermost
Outermost
Outermost
Contact
Contact
Contact
Contact
Contact





and D3
Surface
Surface
Surface
Resistance
Resistance
Resistance
Resistance
Resistance





[nm]
[at]
[at %]
[at %]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]







Example
3
30
7.3
2.6
24.1
1-3
1-4
1-4
1-4
1-4




77
1
7.4
2.1
25.1
1-3
3-6
1-4
1-4
1-4




5
1
3.4
2.5
35.1
1-3
3-6
4-7
5-8
6-9




89
30
4.1
1.7
38.2
1-3
1-4
1-4
1-4
1-4




90
30
2.2
1.2
57.1
3-5
3-6
3-5
3-5
3-5



Comparative
16
1
1.2
2.5
24.1
1-3



<10



Example
19

7.3

25.1
1-3
<10















Target

≦10
≦10
≦10
≦10
≦10





















TABLE 21









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition





Thickness
Amount

Thickness
Amount

Thickness
Amount




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]





Example
91
Sn
0.03
22
Ag—10Sn
0.03
32
Ni
1.0
0.9



92
Sn
0.03
22
Ag—40Sn
0.03
32
Ni
1.0
0.9



93
Sn—Ag5
0.03
22
Ag
0.03
32
Ni
1.0
0.9



94
Sn—Ag40
0.03
22
Ag
0.03
32
Ni
1.0
0.9
















Target

0.002≦
1≦

0.001≦
1≦

0.005≦
0.03≦




≦0.2
≦150 

≦0.3
≦330 















Inserting Force






Maximum



Inserting

Gas Corrosion Resistance





















Force/Maximum

Heat

Sulfurous
Hydrogen







Inserting Force of

Resistance
Salt Spray
Acid Gas
Sulfide





Heat
Comparative
Contact
Contact
Contact
Contact
Contact
Generation





Treatment
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance
Situation





Condition
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
of Powder







Example
91
None
78
1-3
1-4
1-4
1-4
1-4
Good




92
None
77
1-3
1-4
1-4
1-4
1-4
Good




93
None
75
1-3
1-4
1-4
1-4
1-4
Good




94
None
72
1-3
1-4
1-4
1-4
1-4
Good

















Target

<85
≦10
≦10
≦10
≦10
≦10
Average










or higher





















TABLE 22









A Layer
B Layer
C Layer





















Deposition


Deposition


Deposition





Thickness
Amount

Thickness
Amount

Thickness
Amount




Composition
[μm]
[μg/cm2]
Composition
[μm]
[μg/cm2]
Composition
[μm]
[mg/cm2]





Example
95
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9



96
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9



97
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9



98
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9



99
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9



100
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9



101
Sn
0.03
22
Ag
0.03
32
Ni
1.0
0.9
















Target

0.002≦
1≦

0.001≦
1≦

0.005≦
0.03≦




≦0.2
≦150 

≦0.3
≦330 














Inserting Force





Maximum Inserting

Gas Corrosion Resistance




















Force/Maximum

Heat

Sulfurous
Hydrogen






Inserting Force of

Resistance
Salt Spray
Acid Gas
Sulfide





Heat
Comparative
Contact
Contact
Contact
Contact
Contact





Treatment
Example 1
Resistance
Resistance
Resistance
Resistance
Resistance





Condition
[%]
[mΩ]
[mΩ]
[mΩ]
[mΩ]
[mΩ]







Example
95
None
77
1-3
1-4
1-4
1-4
1-4




96
30° C. ×
76
1-3
1-4
1-4
1-4
1-4





12 h




97
50° C. ×
73
1-3
1-4
1-4
1-4
1-4





12 h




98
50° C. ×
72
3-5
3-7
1-4
1-4
1-4





20 h




99
300° C. ×
73
1-3
1-4
1-4
1-4
1-4





3 sec.




100
500° C. ×
72
1-3
1-4
1-4
1-4
1-4





1 sec.




101
600° C. ×
73
3-5
3-7
1-4
1-4
1-4





1 sec.
















Target

<85
≦10
≦10
≦10
≦10
≦10










Examples 1 to 101 were press-fit terminals, which had the excellent whisker resistance and the low inserting force, were unlikely to cause shaving of plating when the press-fit terminal was inserted into the substrate, and had the high heat resistance.


Comparative Example 1 is a blank material.


Comparative Example 2 was fabricated by making thin the Sn plating of the blank material of Comparative Example 1, but generated whiskers thereby to be poor in the whisker resistance.


Comparative Example 3 was fabricated by being subjected to no heat treatment, in comparison with Comparative Example 2, but generated whiskers thereby to be poor in the whisker resistance, and was higher in the inserting force than the target.


Comparative Example 4 was fabricated by carrying out Cu plating for the C layer, in comparison with Comparative Example 2, but had the inserting force of 90% of Comparative Example 1, which was higher than the target, and was poor in the heat resistance.


Comparative Example 5 was fabricated by making the Sn plating thin, in comparison with Comparative Example 4, but generated whiskers thereby to be poor in the whisker resistance.


Comparative Example 6 was fabricated by being subjected to no heat treatment, in comparison with Comparative Example 5, but generated whiskers thereby to be poor in the whisker resistance, and was higher in the inserting force than the target.


Comparative Example 7 was fabricated by being subjected to Cu plating for the C layer, in comparison with the blank material of Comparative Example 1, but exhibited no variations in the properties in comparison with Comparative Example 1.


Comparative Example 8 was fabricated by making the Ni plating of the C layer thick in comparison with the blank material of Comparative Example 1, but exhibited no variations in the properties in comparison with Comparative Example 1.


Comparative Example 9 was fabricated by making the Sn plating of the outermost surface layer thick in comparison with Example 1, but surely generated one or more whiskers of shorter than 20 μm though there was no whiskers of 20 μm or longer in length, which was the target.


Comparative Example 10 was fabricated by making the Ag plating of the B layer thin in comparison with Comparative Example 9, but surely generated one or more whiskers of shorter than 20 μm though there was no whisker of 20 μm or longer in length, which was the target.


Comparative Example 11 was fabricated by making the Ag plating of the B layer thick in comparison with Example 1, but provided a large amount of powder generated.


Comparative Example 12 was fabricated by carrying out no Ag plating of the B layer in comparison with Comparative Example 11, but was poor in the heat resistance.


Comparative Example 13 was fabricated by making the Ag plating of the B layer thick in comparison with Example 4, but provided a large amount of powder generated.


Comparative Example 14 was fabricated by carrying out no Ag plating of the B layer in comparison with Comparative Example 13, but was poor in the heat resistance.


Comparative Example 15 was fabricated by making the Sn plating of the A layer thin in comparison with Example 4, but was poor in the gas corrosion resistance, and higher in the contact resistance after the hydrogen sulfide gas corrosion test than the target.


Comparative Example 16 was fabricated by making the Sn plating of the A layer thin in comparison with Example 5, but had a maximum value of the atomic concentration (at %) of Sn or In of the A layer of 10 at % or lower in a depth measurement by XPS (X-ray photoelectron spectroscopy), was poor in the gas corrosion resistance, and higher in the contact resistance after the hydrogen sulfide gas corrosion test than the target.


Comparative Example 17 was fabricated by reversing the plating order of Sn and Ag in comparison with Example 3, but was poor in the gas corrosion resistance and higher in the contact resistance after the hydrogen sulfide gas corrosion test than the target, because in a depth measurement by XPS (X-ray photoelectron spectroscopy), the position (D1) where the atomic concentration (at %) of Sn or In of the A layer was the maximum value and the position (D2) where the atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of the B layer was the maximum value were present in the order of D2 and D1.


Comparative Example 18 was fabricated by making the Ni plating thin in comparison with Example 3, but had the high inserting force, and was poor in the heat resistance, because in a depth measurement by XPS (X-ray photoelectron spectroscopy), a depth where the atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, or Cu of the C layer was 25 at % or higher was shallower than 50 nm.


Comparative Example 19 was poor in the heat resistance, because Sn of the A layer was thin, and the B layer was not formed.



FIG. 2 shows a depth measurement result by XPS (X-ray photoelectron spectroscopy) in Example 3. It is clear from FIG. 2 that the position (D1) where the atomic concentration (at %) of Sn or In of the A layer was the maximum value and the position (D2) where the atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of the B layer was the maximum value were present in the order of D1 and D2; and D1 had 35 at %, and D2 had 87 at %.



FIG. 3 shows a survey measurement result by XPS (X-ray photoelectron spectroscopy) in Example 3. It is clear from FIG. 3 that O was 24.1 at %; Ag was 2.6 at %; and Sn was 7.3 at %.


REFERENCE SIGNS LIST






    • 10 METAL MATERIAL FOR PRESS-FIT TERMINAL


    • 11 BASE MATERIAL


    • 12 C LAYER


    • 13 B LAYER


    • 14 A LAYER




Claims
  • 1. A press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; anda substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate,wherein at least the substrate connection part has the surface structure described below;the surface structure comprises:an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; anda C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; whereinthe A layer has a thickness of 0.002 to 0.2 μm, and a surface arithmetic average height (Ra) of 0.1 μm or lower;the B layer has a thickness of 0.001 to 0.3 μm; andthe C layer has a thickness of 0.05 μm or larger.
  • 2. The press-fit terminal according claim 1, wherein the A layer has a thickness of 0.01 to 0.1 μm, and the press-fit terminal has a low inserting force and causes less shaving of plating.
  • 3. The press-fit terminal according to claim 1, wherein the B layer has a thickness of 0.005 to 0.1 μm, and the press-fit terminal has a low inserting force and causes less shaving of plating.
  • 4. A press-fit terminal comprising: a female terminal connection part provided at one side of an attached part to be attached to a housing; anda substrate connection part provided at the other side and attached to a substrate by press-fitting the substrate connection part into a through-hole formed in the substrate,wherein at least the substrate connection part has the surface structure described below;the surface structure comprises:an A layer formed as an outermost surface layer and formed of Sn, In, or an alloy thereof;a B layer formed below the A layer and constituted of one or two or more selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; anda C layer formed below the B layer and constituted of one or two or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu; whereinthe A layer has a deposition amount of Sn, In of 1 to 150 μg/cm2, and a surface arithmetic average height (Ra) of 0.1 μm or lower;the B layer has a deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir of 1 to 330 μg/cm2; andthe C layer has a deposition amount of Ni, Cr, Mn, Fe, Co, Cu of 0.03 mg/cm2 or larger.
  • 5. The press-fit terminal according to claim 4, wherein the A layer has a deposition amount of Sn, In of 7 to 75 μg/cm2, and the press-fit terminal has a low inserting force and causes less shaving of plating.
  • 6. The press-fit terminal according to claim 4, wherein the B layer has a deposition amount of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir of 4 to 120 μg/cm2, and the press-fit terminal has a low inserting force and causes less shaving of plating.
  • 7. The press-fit terminal according to claim 1 or 4, wherein the A layer has an alloy composition comprising 50 mass % or more of Sn, In, or a total of Sn and In, and the other alloy component(s) comprising one or two or more metals selected from the group consisting of Ag, As, Au, Bi, Cd, Co, Cr, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Sn, W, and Zn.
  • 8. The press-fit terminal according claim 1 or 4, wherein the B layer has an alloy composition comprising 50 mass % or more of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir, or a total of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir, and the other alloy component(s) comprising one or two or more metals selected from the group consisting of Ag, Au, Bi, Cd, Co, Cu, Fe, In, Ir, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Ru, Sb, Se, Sn, W, Tl, and Zn.
  • 9. The press-fit terminal according to claim 1 or 4, wherein the C layer has an alloy composition comprising 50 mass % or more of a total of Ni, Cr, Mn, Fe, Co, and Cu, and further comprising one or two or more selected from the group consisting of B, P, Sn, and Zn.
  • 10. The press-fit terminal according to claim 1 or 4, wherein the A layer has a surface indentation hardness of 1,000 MPa or higher.
  • 11. The press-fit terminal according to claim 1 or 4, wherein the A layer has a surface indentation hardness of 10,000 MPa or lower.
  • 12. The press-fit terminal according to claim 1 or 4, wherein when a depth analysis by XPS (X-ray photoelectron spectroscopy) is carried out, a position (D1) where an atomic concentration (at %) of Sn or In of the A layer is a maximum value, a position (D2) where an atomic concentration (at %) of Ag, Au, Pt, Pd, Ru, Rh, Os, or Ir of the B layer is a maximum value, and a position (D3) where an atomic concentration (at %) of Ni, Cr, Mn, Fe, Co, or Cu of the C layer is a maximum value are present in the order of D1, D2, and D3 from the outermost surface.
  • 13. The press-fit terminal according to claim 1 or 4, wherein the press-fit terminal is fabricated by forming surface-treated layers on the substrate connection part in the order of the C layer, the B layer, and the A layer by a surface treatment, and thereafter heat-treating the surface-treated layers.
  • 14. An electronic component comprising a press-fit terminal according to claim 1 or 4.
Priority Claims (1)
Number Date Country Kind
2012-022541 Feb 2012 JP national
PCT Information
Filing Document Filing Date Country Kind
PCT/JP2013/052102 1/30/2013 WO 00
Publishing Document Publishing Date Country Kind
WO2013/115276 8/8/2013 WO A
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Related Publications (1)
Number Date Country
20150011132 A1 Jan 2015 US