JP5298233B2 - Metal material for electronic parts and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal material for electronic parts having a low insertion and removal characteristic, a low whisker, and a high durability and a method for manufacturing the same. <P>SOLUTION: The metal material 10 for electronic parts includes: a base material 11; a layer A 14 composing a top surface layer of the base material 11 and formed of Sn, In, or an alloy therof; and a layer B 13 provided between the base material 11 and the layer A 14 to compose an intermediate layer and formed of Ag, Au, Pt, Pd, Ru, Rh, Os, Ir, or an alloy thereof. The thickness of the top surface layer (layer A) 14 is thicker than 0.2 &mu;m and that of the intermediate layer (layer B) 13 is 0.001 &mu;m or thicker. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention relates to a metal material for electronic parts and a method for producing the same.

  A connector that is a connection part for consumer and in-vehicle electronic devices uses a material in which a surface of brass or phosphor bronze is plated with Ni or Cu and further plated with Sn or Sn alloy. . Sn or Sn alloy plating generally requires characteristics such as low contact resistance and high solder wettability, and in recent years, it is also required to reduce insertion force when mating a male terminal and a female terminal formed by plating a plated material. ing. In addition, whiskers that are needle-like crystals that cause problems such as short circuits may occur on the plating surface in the manufacturing process, and it is necessary to suppress these whiskers well.

  On the other hand, in Patent Document 1, a surface layer having a thickness of 0.05 μm or more from the surface is partially coated with Ag or an Ag alloy on a substrate made of Ni, Co or an alloy thereof, A silver-coated electrical material is disclosed in which In, Zn, Sn, Pd, or an alloy thereof is coated to a thickness of 0.01 to 1.0 μm on a partially coated Ag or Ag alloy layer. According to this, it is described that excellent solderability as an electrical material and connectivity in mechanical electrical connection can be maintained over a long period of time.

  In Patent Document 2, a first coating layer of Ni, Co, or an alloy containing these is provided on the surface of a Cu or Cu alloy base material, and a second coating layer of Ag or an Ag alloy is provided on the surface, and the surface is further provided. Discloses a Sn or Sn alloy coating material provided with a coating layer of Sn or Sn alloy. According to this, it is possible to provide a Sn or Sn alloy coating material that has no surface oxidative discoloration, little increase in contact resistance, and good appearance and contact characteristics over a long period of time regardless of use at high temperatures. Have been described.

  Further, in Patent Document 3, a first coating layer of Ni, Co or an alloy containing these is provided on the surface of a Cu or Cu alloy base material, a second coating layer of Ag or an Ag alloy is provided on the surface, and the surface is further provided. Discloses an Sn or Sn alloy coating material provided with an Sn or Sn alloy melt-solidified coating layer. According to this, it is possible to provide a Sn or Sn alloy coating material that has no surface oxidative discoloration, little increase in contact resistance, good appearance and contact characteristics over a long period of time regardless of use at high temperatures. Have been described.

  Patent Document 4 discloses an electrical contact material in which an Ag layer or an Ag alloy layer is coated on one surface of a conductive strip and an Sn layer or an Sn alloy layer is coated on the other surface. . According to this, it is described that an electrical contact material or an electrical contact component with little deterioration of solderability even when exposed to a sulfurized environment or the like can be provided.

  Patent Document 5 includes (a) any one of a metal thin film for a base selected from the group consisting of silver, palladium, platinum, bismuth, indium, nickel, zinc, titanium, zirconium, aluminum, chromium, and antimony. There is disclosed a method for preventing tin whiskers by pretreatment, which is characterized in that after being formed on an object to be plated, (b) a tin or tin alloy plating film is formed on the metal thin film for the base. And according to this, it is possible to effectively prevent tin whiskers by a simple operation in a tin-based film formed in order to ensure good solderability on the surface of an object to be plated such as a copper-based substrate. It is stated that you can.

  Further, in Patent Document 6, a silver plating layer is formed on the surface of a plating base, and further, a tin, indium or zinc plating layer having a thickness of 0.001 to 0.1 μm is formed on the surface of the silver plating layer. A plating structure obtained by heat-treating a silver plating structure is obtained. And according to this, the support for storing a light-emitting element having excellent heat resistance and low reflectivity reduction due to silver sulfidation, and for electric parts that are hard to discolor due to sulfidation, have the original gloss of silver, and have low contact resistance It is described that a coating method can be provided.

JP 61-124597 A JP-A-1-306574 JP-A-2-301573 JP-A-9-78287 JP 2003-129278 A JP 2011-122234 A

However, the technique described in Patent Document 1 has a problem that the contact resistance increases in a region where Sn is formed extremely thin.
Moreover, in the techniques described in Patent Documents 2 to 5, the solder wettability or contact characteristics are good, but it cannot be said that the technique is satisfactory with respect to insertion / removability and whisker suppression.
Further, in the technique described in Patent Document 6, although the contact resistance is improved, it cannot be said that the solder wettability is satisfactory.
As described above, the metal material for electronic parts having the conventional Sn / Ag / Ni base plating structure has problems in insertion / removability and whiskers. Even if there is no problem in insertion / removability or whiskers, durability (heat resistance, It has been difficult to achieve satisfactory specifications for gas corrosion resistance and high solder wettability, and it has not been clarified.
The present invention has been made to solve the above-described problems, and has low insertion / extraction (low insertion / extraction indicates that the insertion force generated when a male terminal and a female terminal are fitted together is low), low whisker It is another object of the present invention to provide a metal material for electronic parts having high durability and a method for producing the same.

  As a result of intensive studies, the present inventors have provided an intermediate layer and an outermost layer in order on a base material, and formed the intermediate layer and the outermost layer with a predetermined metal and with a predetermined thickness or adhesion amount. It has been found that a metal material for electronic parts having all of insertability / removability, low whisker property and high durability can be produced.

The present invention completed on the basis of the above knowledge, in one aspect, comprises a base material, an outermost layer of the base material, an A layer formed of Sn, In, or an alloy thereof, the base material and A A middle layer, and a B layer formed of Ag, Au, Pt, Pd , Rh, Os, Ir, or an alloy thereof, and the thickness of the outermost layer (A layer) There is less than 0.2μm greater and 0.6 [mu] m, the and the alloy composition of the surface layer (a layer) is Sn, in or the sum of Sn and an in 50 mass% or more, the remaining alloy component Ag , As, Au, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, W, made of one or more metals selected from the group consisting of Zn , the thickness of the middle layer (B layer) is 0.001 ~0.3μm, the alloy of the middle layer (B layer) Composition Ag, Au, Pt, Pd, Rh, Os, Ir, or not less than 50 wt%, the total of Ag and Au and Pt and Pd and Rh and Os and Ir, the remaining alloy component Bi, Cd, Low whisker property consisting of one or more metals selected from the group consisting of Co, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Se, Sn , W, Tl, Zn , and It is a metal material for electronic parts having high durability.

In another aspect of the present invention, a base material, an outermost layer of the base material, and formed between Sn, In, or an alloy thereof, and the base material and the A layer are provided. And an intermediate layer, and a B layer formed of Ag, Au, Pt, Pd , Rh, Os, Ir, or an alloy thereof, and the amount of Sn and In deposited on the outermost layer (A layer) is 150 [mu] g / cm ² an ultra and less than 450 [mu] g / cm ^2, wherein it is the alloy composition of the surface layer (a layer) is Sn, in or the sum of Sn and an in 50 mass% or more, the remaining alloy component Ag, As, Au, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, W, made of one or more metals selected from the group consisting of Zn , Ag of the middle layer (B layer), Au, Pt, Pd, Rh, Os, the amount of deposition of Ir 1 330μg / cm ^2, the middle layer 50 in total alloy composition is Ag, Au, Pt, Pd, Rh, Os, Ir or Ag and Au and Pt and Pd and Rh and Os and Ir, the (B layer) The remaining alloy component is selected from the group consisting of Bi, Cd, Co, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Se, Sn, W, Tl, and Zn. It is a metal material for electronic parts having low whisker properties and high durability composed of seeds or two or more metals .

  In still another embodiment of the metal material for electronic parts of the present invention, the arithmetic average height (Ra) of the surface of the outermost layer (A layer) is 0.1 μm or less.

  In still another embodiment of the metal material for electronic parts according to the present invention, the maximum height (Rz) of the surface of the outermost layer (A layer) is 1 μm or less.

  In still another embodiment of the metal material for electronic parts of the present invention, the reflection density on the surface of the outermost layer (A layer) is 0.3 or more.

In another embodiment, the metal material for electronic parts according to the present invention is subjected to depth analysis by XPS (X-ray photoelectron spectroscopy), and the Sn or In atomic concentration (at%) of the outermost layer (A layer) The position (D ₁ ) indicating the maximum value of Ag, the position (D ₂ ) indicating the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer) It exists in the order of D ₁ and D ₂ from the outermost surface.

In another embodiment, the metal material for electronic parts of the present invention is subjected to depth analysis by XPS (X-ray photoelectron spectroscopy), and Ag, Au, Pt, Pd , Rh, Os of the intermediate layer (B layer). Alternatively, the maximum value of the atomic concentration (at%) of Ir is 10 at% or more.

  In still another embodiment, the metal material for electronic parts of the present invention is provided between the base material and the B layer to form a lower layer, and is made of a group consisting of Ni, Cr, Mn, Fe, Co, and Cu. A C layer formed of one or two or more selected types is further provided.

  In still another embodiment of the metal material for electronic parts according to the present invention, the composition of the alloy of the lower layer (C layer) is 50% by mass or more in total of Ni, Cr, Mn, Fe, Co, Cu, and B , P, Sn, Zn, or one or more selected from the group consisting of Zn.

In another embodiment, the metal material for electronic parts according to the present invention is subjected to depth analysis by XPS (X-ray photoelectron spectroscopy), and the Sn or In atomic concentration (at%) of the outermost layer (A layer) The position (D ₁ ) showing the highest value of Ag, the position (D ₂ ) showing the highest value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer), The position (D ₃ ) showing the maximum value of atomic concentration (at%) of Ni, Cr, Mn, Fe, Co or Cu in the lower layer (C layer) exists in the order of D ₁ , D ₂ , D ₃ from the outermost surface. .

In another embodiment, the metal material for electronic parts of the present invention is subjected to depth analysis by XPS (X-ray photoelectron spectroscopy), and Ag, Au, Pt, Pd , Rh, Os of the intermediate layer (B layer). Or the maximum value of the atomic concentration (at%) of Ir is 10 at% or more, and the atomic concentration (at%) of Ni, Cr, Mn, Fe, Co or Cu in the lower layer (C layer) is 25% or more. A certain depth is 50 nm or more.

  In still another embodiment of the metal material for electronic parts according to the present invention, the lower layer (C layer) has a thickness of 0.05 μm or more.

In still another embodiment of the metal material for electronic parts of the present invention, the adhesion amount of Ni, Cr, Mn, Fe, Co, Cu in the lower layer (C layer) is 0.03 mg / cm ² or more.

  In still another embodiment of the metal material for electronic parts according to the present invention, the intermediate layer (B layer) has a thickness of 0.005 to 0.1 μm.

In still another embodiment of the metal material for electronic parts of the present invention, the adhesion amount of Ag, Au, Pt, Pd , Rh, Os, Ir in the intermediate layer (B layer) is 4 to 120 μg / cm ² .

  In still another embodiment of the metal material for electronic parts according to the present invention, the surface of the lower layer (C layer) has a Vickers hardness of Hv300 or more.

In still another embodiment, the metal material for electronic parts according to the present invention has a Vickers hardness and thickness of the surface of the lower layer (C layer) represented by the following formula:
Vickers hardness (Hv) ≧ −376.22 Ln (thickness μm) +86.411
Meet.

  In yet another embodiment, the metal material for electronic parts of the present invention hits the surface of the lower layer (C layer) with a load of 980.7 mN and a load holding time of 15 seconds using an ultra-micro hardness tester. The indentation hardness of the surface of the lower layer (C layer), which is the hardness obtained by measuring the above, is 2500 MPa or more.

In yet another embodiment, the metal material for electronic parts of the present invention hits the surface of the lower layer (C layer) with a load of 980.7 mN and a load holding time of 15 seconds using an ultra-micro hardness tester. The indentation hardness and thickness of the surface of the lower layer (C layer), which is the hardness obtained by measuring in the following formula:
Indentation hardness (MPa) ≧ −3998.4Ln (thickness μm) +1178.9
Meet.

  In still another embodiment of the metal material for electronic parts according to the present invention, the surface of the lower layer (C layer) has a Vickers hardness of Hv1000 or less.

  In yet another embodiment, the metal material for electronic parts of the present invention hits the surface of the lower layer (C layer) with a load of 980.7 mN and a load holding time of 15 seconds using an ultra-micro hardness tester. The indentation hardness of the surface of the lower layer (C layer), which is the hardness obtained by measuring the above, is 10,000 MPa or less.

  In still another embodiment of the metal material for electronic parts according to the present invention, the substrate is a metal substrate, and the Vickers hardness of the surface of the metal substrate is Hv90 or more.

  In still another embodiment of the metal material for electronic parts according to the present invention, the base material is a metal base material, and a load of 980.7 mN is applied to the surface of the metal base material by an ultra micro hardness tester. The indentation hardness of the surface of the metal base material, which is the hardness obtained by measuring the root with a holding time of 15 seconds, is 1000 MPa or more.

  In still another embodiment of the metal material for electronic parts according to the present invention, the base material is a metal base material, and the tensile speed is set to 50 mm / min in the rolling parallel direction of the metal base material in accordance with JIS C2241. The elongation of the metal substrate measured by conducting a tensile test is 5% or more.

  In still another embodiment, the metal material for electronic parts according to the present invention is a metal substrate, and a W-bending test is performed according to Japan Copper and Brass Association Technical Standard (JCBA) T307. The minimum bending radius ratio (MBR / t) of the metal substrate, which is the ratio of the minimum bending radius (MBR) at which no cracking occurs and the metal material thickness (t), is 3 or less.

In another embodiment, the metal material for electronic parts according to the present invention is subjected to depth analysis by XPS (X-ray photoelectron spectroscopy), and the Sn or In atomic concentration (at%) of the outermost layer (A layer) Between the position (D ₁ ) indicating the maximum value of Ni and the position (D ₃ ) indicating the maximum value of the atomic concentration (at%) of Ni, Cr, Mn, Fe, Co, Cu or Zn of the lower layer (C layer) , Ag, Au, Pt, Pd , Rh, Os, or Ir, a region of 40 at% or more exists with a thickness of 1 nm or more.

  In yet another embodiment, the metal material for electronic parts of the present invention is less than 50 at% when elemental analysis of the surface of the outermost layer (A layer) is performed by Survey measurement of XPS (X-ray photoelectron spectroscopy). It is.

  In still another aspect of the present invention, there is provided a connector terminal using the metal material for electronic parts of the present invention as a contact portion.

  In still another aspect, the present invention is a connector using the connector terminal of the present invention.

  In still another aspect of the present invention, there is provided an FFC terminal using the metal material for electronic parts of the present invention as a contact portion.

  In still another aspect, the present invention is an FPC terminal using the metal material for electronic parts of the present invention as a contact portion.

  In still another aspect, the present invention is an FFC using the FFC terminal of the present invention.

  In still another aspect, the present invention is an FPC using the FPC terminal of the present invention.

  In still another aspect of the present invention, an electronic component using the metal material for an electronic component of the present invention as an external connection electrode.

  In still another aspect of the present invention, in the method for producing a metal material for electronic parts according to the present invention, the method includes the step of forming the outermost layer (A layer) and the intermediate layer (B layer) by surface treatment using wet plating. is there.

  In one embodiment of the method for producing a metal material for electronic parts of the present invention, the wet plating method is electroplating.

  In another embodiment of the method for producing a metal material for electronic components of the present invention, the outermost layer (A layer) is formed by a plating treatment using an acidic plating solution.

  In still another embodiment of the method for producing a metal material for electronic parts according to the present invention, the intermediate layer (B layer) is formed by plating using a cyan-containing plating solution.

  In still another embodiment of the method for producing a metal material for electronic parts according to the present invention, the lower layer (C layer) includes a step of forming by plating using a sulfamic acid bath or a watt bath.

  In still another embodiment of the method for producing a metal material for electronic parts of the present invention, the plating solution used in the sulfamic acid bath and the Watt bath is a bright Ni plating solution.

  In still another embodiment of the method for producing a metal material for electronic parts of the present invention, saccharin is contained as an additive in the plating solution for forming the lower layer (C layer).

  ADVANTAGE OF THE INVENTION According to this invention, the metal material for electronic components which has low insertion / extraction property, low whisker property, and high durability, and its manufacturing method can be provided.

It is a schematic diagram which shows the structure of the metal material for electronic components which concerns on embodiment of this invention. It is a reference example of the depth measurement result of XPS (X-ray photoelectron spectroscopy) of the metal material for electronic components which concerns on embodiment of this invention.

  Hereinafter, the metal material for electronic components according to the embodiment of the present invention will be described. As shown in FIG. 1, a metal material 10 for an electronic component according to an embodiment has a lower layer (C layer) 12 formed on the surface of a base material 11, and a middle layer (B layer) 13 on the surface of the lower layer (C layer) 12. The outermost layer (A layer) 14 is formed on the surface of the middle layer (B layer) 13. Further, the lower layer (C layer) 12 is not formed on the surface of the base material 11, the middle layer (B layer) 13 is formed on the surface of the base material 11, and the outermost layer (A layer) is formed on the surface of the middle layer (B layer) 13. The material in which 14 is formed is also a metal material for electronic components according to the embodiment of the present invention.

<Configuration of metal materials for electronic parts>
(Base material)
Although it does not specifically limit as the base material 11, For example, metal base materials, such as copper and a copper alloy, Fe-type material, stainless steel, titanium and a titanium alloy, aluminum, and an aluminum alloy, can be used. Alternatively, a metal base and a resin layer may be combined. Examples of composites of metal layers and resin layers include electrode portions on FPC or FFC substrates.
The Vickers hardness of the substrate 11 is preferably Hv90 or higher. When the Vickers hardness of the substrate 11 is Hv90 or more, the thin substrate lubrication effect is improved by the hard substrate, and the insertion / extraction force is further reduced.
The indentation hardness of the substrate 11 is preferably 1000 MPa or more. When the indentation hardness of the substrate 11 is 1000 MPa or more, the thin substrate lubrication effect is improved by the hard substrate, and the insertion / extraction force is further reduced.
The elongation of the substrate 11 is preferably 5% or more. When the elongation of the substrate 11 is 5% or more, the bending workability is improved, and when the metal material for electronic parts of the present invention is press-molded, cracks are hardly formed in the molded part, and gas corrosion resistance ( (Durability) suppresses the decrease.
The minimum bending radius ratio (MBR / t) when the W-bending test is performed on the substrate 11 is preferably 3 or less. When the minimum bending radius ratio (MBR / t) of the substrate 11 is 3 or less, bending workability is improved, and when the metal material for electronic parts of the present invention is press-molded, cracks are hardly formed in the molded part. This suppresses the decrease in gas corrosion resistance (durability).

(Outermost layer (A layer))
The outermost layer (A layer) 14 needs to be Sn, In, or an alloy thereof. Sn and In are oxidizable metals, but are relatively soft among metals. Therefore, even if an oxide film is formed on the Sn and In surfaces, for example, when a male terminal and a female terminal are mated using a metal material for electronic parts as a contact material, the oxide film is easily scraped, and a new surface of Sn and In is formed. Low contact resistance can be obtained because the faces are exposed and the contacts are made of metal.
Sn and In are excellent in gas corrosion resistance against gases such as chlorine gas, sulfurous acid gas, and hydrogen sulfide gas. For example, the middle layer (B layer) 13 is inferior in gas corrosion resistance and the lower layer (C layer) 12 in. When Ni is inferior in gas corrosion resistance, and copper and copper alloy inferior in gas corrosion resistance are used for the base material 11, there is a function of improving the gas corrosion resistance of the metal material for electronic parts. For Sn and In, Sn is preferable because In is strictly regulated based on the technical guidelines for preventing health problems of the Ministry of Health, Labor and Welfare.

  The composition of the outermost layer (A layer) 14 is 50 mass% or more in total of Sn, In, or Sn and In, and the remaining alloy components are Ag, As, Au, Bi, Cd, Co, Cr, Cu, You may be comprised by the 1 type selected from the group which consists of Fe, Mn, Mo, Ni, Pb, Sb, W, Zn, or 2 or more types of metals. Since the composition of the outermost layer (A layer) 14 is an alloy (for example, Sn-Ag plating is applied), low insertion / removability, low whisker property, and durability (heat resistance, gas corrosion resistance, solder wettability, etc.) ) May be further improved.

  The thickness of the outermost layer (A layer) 14 needs to be thicker than 0.2 μm. The thickness of the outermost layer (A layer) 14 is preferably more than 0.2 μm and less than 0.6 μm. When the thickness of the outermost layer (A layer) 14 is thicker than 0.2 μm, durability (heat resistance, gas corrosion resistance, solder wettability, etc.) is improved. Further, when the thickness is increased, whiskers are likely to be generated, and the adhesion wear of Sn and In is increased and the insertion / extraction force is increased. In order to obtain more sufficient low whisker properties, it is preferably less than 0.6 μm. When the thickness is less than 0.6 μm, whiskers having a length of 20 μm or more are not generated.

The amount of Sn and In deposited on the outermost layer (A layer) 14 needs to be larger than 150 μg / cm ² . Adhesion amount of the surface layer (A layer) 14, 150 [mu] g / cm ² ultra and less than 450 [mu] g / cm ² is preferred. Here, the reason for defining the amount of adhesion will be described. For example, when the thickness of the outermost layer (A layer) 14 is measured with a fluorescent X-ray film thickness meter, it is measured by an alloy layer formed between, for example, the outermost layer (A layer) and the middle layer (B layer) therebelow. An error may occur in the thickness value to be formed. On the other hand, when controlling by the adhesion amount, more accurate quality control can be performed regardless of the formation state of the alloy layer. If the adhesion amount of Sn and In on the outermost layer (A layer) 14 is more than 150 μg / cm ² , the gas resistance is improved. Further, when the adhesion amount increases, whiskers are likely to be generated, and the adhesion wear of Sn and In increases and the insertion / extraction force also increases. In order to obtain more sufficient low whisker properties, it is preferably less than 450 μg / cm ² . When the adhesion amount is less than 450 μg / cm ² , whiskers having a length of 20 μm or more are not generated.

(Middle layer (B layer))
The middle layer (B layer) 13 needs to be formed of Ag, Au, Pt, Pd , Rh, Os, Ir, or an alloy thereof. Ag, Au, Pt, Pd , Rh, Os, and Ir are characterized by having relatively heat resistance among metals. Therefore, it suppresses that the composition of the base material 11 and the lower layer (C layer) 12 diffuses to the outermost layer (A layer) 14 side, and improves heat resistance. Further, these metals form a compound with Sn or In of the outermost layer (A layer) 14 to suppress the formation of an oxide film of Sn or In and improve solder wettability. Among Ag, Au, Pt, Pd , Rh, Os, and Ir, Ag is more desirable from the viewpoint of conductivity. Ag has high conductivity. For example, when Ag is used for high-frequency signal applications, the impedance resistance is lowered due to the skin effect.
The alloy composition of the middle layer (B layer) 13 is Ag, Au, Pt, Pd , Rh, Os, Ir, or the total of Ag, Au, Pt, Pd , Rd, Os, and Ir is 50% by mass or more. One or more metals selected from the group consisting of Bi, Cd, Co, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Se, Sn, W, Tl, and Zn It may consist of. When such an alloy composition is used (for example, Sn-Ag plating is applied), the low insertion / extraction property, the low whisker property, and the durability (heat resistance, gas corrosion resistance, solder wettability, etc.) are improved. There is.

  The thickness of the middle layer (B layer) 13 needs to be 0.001 μm or more. The thickness of the middle layer (B layer) 13 is preferably 0.005 to 0.1 μm. When the thickness is less than 0.001 μm, the solder wettability is poor. In order to obtain sufficient solder wettability, a thickness of 0.005 μm or more is preferable. Further, when the thickness is increased, the insertion / extraction force is increased, and the thickness is preferably 0.3 μm or less, more preferably 0.1 μm or less, in order to obtain a sufficient low insertion / extraction property.

The adhesion amount of Ag, Au, Pt, Pd , Rh, Os, Ir, or their alloys in the middle layer (B layer) 13 needs to be 1 μg / cm ² or more. The adhesion amount of the middle layer (B layer) 13 is preferably ⁴ to 120 μg / cm ² . Here, the reason for defining the amount of adhesion will be described. For example, when measuring the thickness of the middle layer (B layer) 13 with a fluorescent X-ray film thickness meter, for example, by an alloy layer formed between the outermost layer (A layer) 14 and the middle layer (B layer) 13 therebelow, There may be an error in the measured thickness value. On the other hand, when controlling by the adhesion amount, more accurate quality control can be performed regardless of the formation state of the alloy layer. When the adhesion amount is less than 4 μg / cm ² , the solder wettability is poor. In order to obtain more sufficient solder wettability, an adhesion amount of 4 μg / cm ² or more is preferable. Further, when the deposition amount is large, it increases insertion force is large, in order to obtain a more satisfactory low insertion resistance 330μg / cm ² or less, more preferably 120 [mu] g / cm ² or less.

(Lower layer (C layer))
Between the base material 11 and the middle layer (B layer) 13, a lower layer (C layer) 12 made of one or more selected from the group consisting of Ni, Cr, Mn, Fe, Co and Cu is provided. Preferably formed. By forming the lower layer (C layer) 12 using one or more metals selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu, by forming a hard lower layer (C layer) The thin film lubrication effect is improved and the low insertion / extraction property is improved, and the lower layer (C layer) 12 prevents the constituent metal of the base material 11 from diffusing into the middle layer (B layer), and the heat resistance test and gas corrosion resistance test. Durability is improved, for example, by suppressing subsequent increase in contact resistance and solder wettability deterioration.

  The alloy composition of the lower layer (C layer) 12 is 50% by mass or more in total of Ni, Cr, Mn, Fe, Co, and Cu, and is further selected from the group consisting of B, P, Sn, and Zn, Or 2 or more types may be included. When the alloy composition of the lower layer (C layer) 12 has such a configuration, the lower layer (C layer) is further cured, so that the thin film lubrication effect is further improved and the low insertion / extraction property is improved. The alloying of 12 further prevents the constituent metal of the base material 11 from diffusing into the middle layer (B layer), suppresses the increase in contact resistance and solder wettability after the heat resistance test and gas corrosion resistance test, etc. Durability is improved.

  The thickness of the lower layer (C layer) 12 is preferably 0.05 μm or more. When the thickness of the lower layer (C layer) 12 is less than 0.05 μm, the thin film lubrication effect by the hard lower layer (C layer) is lowered and the low insertion / removal property is deteriorated, and the constituent metal of the substrate 11 is the middle layer (B layer). Durability is worsened, such as increased contact resistance after heat resistance test and gas corrosion resistance test and solder wettability deterioration.

The adhesion amount of Ni, Cr, Mn, Fe, Co, and Cu in the lower layer (C layer) 12 is preferably 0.03 mg / cm ² or more. Here, the reason for defining the amount of adhesion will be described. For example, when the thickness of the lower layer (C layer) 12 is measured with a fluorescent X-ray film thickness meter, it is measured with the outermost layer (A layer) 14, the middle layer (B layer) 13, the base material 11 and the alloy layer formed. An error may occur in the thickness value to be formed. On the other hand, when controlling by the adhesion amount, more accurate quality control can be performed regardless of the formation state of the alloy layer. Further, if the adhesion amount is less than 0.03 mg / cm ² , the thin film lubrication effect by the hard lower layer (C layer) is lowered and the low insertion / removal property is deteriorated, and the constituent metal of the base material 11 diffuses into the middle layer (B layer). The durability deteriorates, for example, the contact resistance increases after the heat resistance test and the gas corrosion resistance test and the solder wettability easily deteriorates.

(Heat treatment)
After the outermost layer (A layer) 14 is formed, heat treatment may be performed for the purpose of improving low insertion / removability, low whisker properties, and durability (heat resistance, gas corrosion resistance, solder wettability, etc.). Heat treatment makes it easy for the outermost layer (A layer) 14 and the middle layer (B layer) 13 to form an alloy layer, and by lowering the Sn adhesion force, low insertion / removability is obtained, and low whisker properties and durability are also achieved. Further improve. In addition, about this heat processing, process conditions (temperature x time) can be selected suitably. Further, this heat treatment is not particularly required.

(Post-processing)
For the purpose of improving low insertability and durability (heat resistance, gas corrosion resistance, solder wettability, etc.) after heat treatment on the outermost layer (A layer) 14 or the outermost layer (A layer) 14 Post-processing may be performed. Post-treatment improves lubricity, provides further low insertion / extraction, and suppresses oxidation of outermost layer (A layer) and middle layer (B layer), heat resistance, gas corrosion resistance, solder wettability, etc. Improves durability. Specific post-treatment includes phosphate treatment, lubrication treatment, silane coupling treatment, etc. using an inhibitor. In addition, about this heat processing, process conditions (temperature x time) can be selected suitably. Further, this heat treatment is not particularly required.

<Characteristics of metal materials for electronic parts>
The Vickers hardness of the surface of the outermost layer (A layer) (measured from the surface of the outermost layer) is preferably Hv90 or higher. When the Vickers hardness of the surface of the outermost layer (A layer) 14 is Hv90 or more, the thin outermost layer (A layer) improves the thin film lubrication effect and improves low insertion / extraction. On the other hand, the Vickers hardness of the outermost layer (A layer) 14 surface (measured from the surface of the outermost layer) is preferably Hv300 or less. When the Vickers hardness of the surface of the outermost layer (A layer) 14 is Hv300 or less, bending workability is improved, and when the metal material for electronic parts of the present invention is press-molded, cracks are hardly formed in the molded part. Become.
The indentation hardness of the surface of the outermost layer (A layer) 14 (measured from the surface of the outermost layer) is preferably 1000 MPa or more. When the indentation hardness of the surface of the outermost layer (A layer) 14 is 1000 MPa or more, the thin outermost layer (A layer) improves the thin film lubrication effect and improves the low insertion / extraction property. On the other hand, the indentation hardness of the surface of the outermost layer (A layer) 14 (measured from the surface of the outermost layer) is preferably 4200 MPa or less. When the indentation hardness of the surface of the outermost layer (A layer) 14 is 4200 MPa or less, bending workability is improved, and when the metal material for electronic parts of the present invention is press-molded, cracks are hardly formed in the molded part. This suppresses the decrease in gas corrosion resistance (durability).

The arithmetic average height (Ra) of the surface of the outermost layer (A layer) 14 is preferably 0.1 μm or less. When the arithmetic average height (Ra) of the surface of the outermost layer (A layer) 14 is 0.1 μm or less, convex portions that are relatively easily corroded are reduced and smoothed, and thus the gas corrosion resistance is improved.
The maximum height (Rz) of the surface of the outermost layer (A layer) 14 is preferably 1 μm or less. When the maximum height (Rz) of the surface of the outermost layer (A layer) 14 is 1 μm or less, the number of convex portions that are relatively easy to corrode is reduced and the surface becomes smooth, so that the gas corrosion resistance is improved.
The reflection density of the surface of the outermost layer (A layer) 14 is preferably 0.3 or more. When the reflection density on the surface of the outermost layer (A layer) 14 is 0.3 or more, the gas corrosion resistance is improved.

  The Vickers hardness of the lower layer (C layer) 12 is preferably Hv300 or more. When the Vickers hardness of the lower layer (C layer) 12 is Hv300 or higher, the lower layer (C layer) is further cured, so that the thin film lubricating effect is further improved and the low insertion / removability is improved. On the other hand, the lower layer (C layer) 12 preferably has a Vickers hardness Hv of 1000 or less. When the Vickers hardness of the lower layer (C layer) 12 is Hv1000 or less, bending workability is improved, and when the metal material for electronic parts of the present invention is press-molded, cracks are hardly formed in the molded part, Suppresses gas corrosion (durability) degradation.

The Vickers hardness of the lower layer (C layer) 12 and the thickness of the lower layer (C layer) 12 are expressed by the following formula:
Vickers hardness (Hv) ≧ −376.22 Ln (thickness μm) +86.411
It is preferable to satisfy. When the Vickers hardness of the lower layer (C layer) 12 and the thickness of the lower layer (C layer) 12 satisfy the above formula, the lower layer (C layer) is further cured, thereby further improving the thin film lubricating effect and improving the low insertion / removability. To do.
In the present invention, “Ln (thickness μm)” means a natural logarithm of thickness (μm).

  The indentation hardness of the lower layer (C layer) 12 is preferably 2500 MPa or more. When the indentation hardness of the lower layer (C layer) 12 is 2500 MPa or more, the low insertion / extraction property is improved. On the other hand, the indentation hardness of the lower layer (C layer) 12 is preferably 10,000 MPa or less. When the indentation hardness of the lower layer (C layer) 12 is 10000 MPa or less, bending workability is improved, and when the metal material for electronic parts of the present invention is press-molded, cracks are hardly formed in the molded portion, Suppresses gas corrosion (durability) degradation.

The indentation hardness of the lower layer (C layer) 12 and the thickness of the lower layer (C layer) 12 are expressed by the following formula:
Indentation hardness (MPa) ≧ −3998.4Ln (thickness μm) +1178.9
It is preferable to satisfy. When the indentation hardness of the lower layer (C layer) 12 and the thickness of the lower layer (C layer) 12 satisfy the above formula, the lower layer (C layer) is further cured, thereby further improving the thin film lubricating effect and improving the low insertion / removability. To do.

When the depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the position (D ₁ ) showing the highest value of the atomic concentration (at%) of Sn or In in the outermost layer (A layer) 14, the middle layer (B layer) 13 It is preferable that the position (D ₂ ) showing the highest atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os, or Ir in the order of D ₁ and D ₂ from the outermost surface. If it does not exist in the order of D ₁ and D ₂ from the outermost surface, sufficient gas corrosion resistance cannot be obtained. If a metal material for electronic parts is subjected to a gas corrosion test such as chlorine gas, sulfurous acid gas, hydrogen sulfide gas, etc., it will corrode. As a result, the contact resistance may increase significantly compared to before the gas corrosion test.
When the depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer) 13 is 10 at% or more. Preferably there is. If the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer) 13 is less than 10 at%, solder wettability may be deteriorated.
When the depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the position (D ₁ ) showing the highest value of the atomic concentration (at%) of Sn or In in the outermost layer (A layer) 14, the middle layer (B layer) 13 The position (D ₂ ) showing the highest atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir of Ni, Cr, Mn, Fe, Co or Cu of the lower layer (C layer) 12 It is preferable that the position (D ₃ ) showing the maximum value of the atomic concentration (at%) of the above exists in the order of D ₁ , D ₂ and D ₃ from the outermost surface. If it does not exist in the order of D ₁ , D ₂ , D ₃ from the outermost surface, sufficient gas corrosion resistance cannot be obtained, and gas corrosion tests such as chlorine gas, sulfurous acid gas, hydrogen sulfide gas, etc. are performed on metal materials for electronic parts. If it is carried out, it may corrode and the contact resistance may increase significantly compared to before the gas corrosion test.
When the depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer) 13 is 10 at% or more. The depth at which the atomic concentration (at%) of Ni, Cr, Mn, Fe, Co or Cu in the lower layer (C layer) 12 is 25 at% or more is preferably 50 nm or more. The maximum atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer) 13 is less than 10 at%, and Ni, Cr, Mn in the lower layer (C layer) 12 When the atomic concentration (at%) of Fe, Co or Cu is 25 at% or more and the depth is less than 50 nm, the low insertion / removability and durability (heat resistance, gas corrosion resistance, solder wettability, etc.) are The base material component may diffuse into the outermost layer (A layer) 14 or the middle layer (B layer) 13 and become worse.
When the depth analysis was performed by XPS (X-ray photoelectron spectroscopy), the position (D ₁ ) indicating the highest value of the atomic concentration (at%) of Sn or In in the outermost layer (A layer) 14 and the lower layer (C layer) 12 40 at% for Ag, Au, Pt, Pd , Rh, Os, or Ir between the position (D ₃ ) where the atomic concentration (at%) of Ni, Cr, Mn, Fe, Co, Cu, or Zn is the highest. The above region is preferably present with a thickness of 1 nm or more. If the thickness is less than 1 nm, for example, Ag, solder wettability may be deteriorated.
When elemental analysis of the surface of the outermost layer (A layer) is performed by Survey measurement by XPS (X-ray photoelectron spectroscopy), O is preferably less than 50 at%. If O is 50 at% or more, the contact resistance may increase.
2, according to an embodiment of the present invention, the outermost layer (A layer) has an Sn thickness of about 0.3 μm, the middle layer (B layer) has an Ag thickness of about 0.2 μm, and the lower layer (C layer) has a thickness of 1. A reference example of a depth measurement result of XPS (X-ray photoelectron spectroscopy) of a metal material for an electronic component when Ni of about 0 μm is used is shown.

<Applications of metal materials for electronic parts>
The use of the metal material for electronic parts of the present invention is not particularly limited. For example, a connector terminal using the metal material for electronic parts as a contact part, an FFC terminal or FPC terminal using the metal material for electronic parts as a contact part, and an electronic part Electronic parts using metal materials for external connection as electrodes for external connection. In addition, about a terminal, it does not depend on the joining method with a wiring side, such as a crimp terminal, a solder terminal, and a press fit terminal. Examples of the external connection electrode include a connection component in which a surface treatment is performed on a tab and a material in which a surface treatment is applied to a semiconductor under bump metal.
Moreover, a connector may be produced using the connector terminal formed in this way, and an FFC or FPC may be produced using an FFC terminal or an FPC terminal.
In the connector, both the male terminal and the female terminal may be the metal material for electronic parts of the present invention, or only one of the male terminal and the female terminal. In addition, low insertion property is further improved by making both the male terminal and the female terminal into the metal material for electronic parts of the present invention.

<Method for producing metal material for electronic parts>
As a method for producing a metal material for electronic parts of the present invention, wet (electrical, electroless) plating, dry (sputtering, ion plating, etc.) plating, or the like can be used.
However, wet plating is less than dry plating because the trace amount of impurity components present in the plating solution is co-deposited in the plating film to suppress whisker generation, and the electrodeposition structure becomes harder, resulting in lower insertion and removal. May be improved. From the viewpoint of production cost, wet plating is preferable.
Of the wet plating, electroplating is preferable. Since electroplating forms a uniform film as compared with electroless plating, durability (heat resistance, gas corrosion resistance, solder wettability, etc.) may be improved.
The outermost layer (A layer) 14 is preferably formed by a plating process using an acidic plating solution. By using acidic plating, adhesion with the middle layer (B layer) 13 is improved.
The middle layer (B layer) 13 is preferably formed by plating using a cyan-containing plating solution. By using cyan-containing plating, a dense film can be formed and durability (heat resistance, gas corrosion resistance, solder wettability, etc.) is improved.
The lower layer (C layer) 12 is preferably formed by plating using a sulfamic acid bath or a watt bath. By using a sulfamic acid bath or a Watt bath, the adhesion to the substrate is improved.
The plating solution used in the sulfamic acid bath or Watt bath is preferably a bright Ni plating solution. By using bright Ni plating as the plating solution, the coating becomes smooth and hard, and low insertability and durability (heat resistance, gas corrosion resistance, solder wettability, etc.) are improved.
Further, it is preferable that saccharin is contained as an additive in the sulfamic acid bath or the Watt bath. By adding saccharin, the film becomes dense and hard, the film becomes smooth and hard, and low insertion / removability and durability (heat resistance, gas corrosion resistance, solder wettability, etc.) are improved.

  EXAMPLES Examples of the present invention will be described below together with comparative examples, but these are provided for better understanding of the present invention and are not intended to limit the present invention.

As examples and comparative examples, samples formed by performing heat treatment with a base material, a lower layer (C layer), an intermediate layer (B layer), and an outermost layer (A layer) in this order are shown in Tables 1 to 7 below. Each was produced under the conditions shown. Moreover, the example which does not form about a lower layer (C layer) was also produced.
Table 1 shows the production conditions for the substrate, Table 2 shows the production conditions for the lower layer (C layer), Table 3 shows the production conditions for the middle layer (B layer), and Table 4 shows the production conditions for the outermost layer (A layer). Table 5 shows the heat treatment conditions. In addition, Table 6 shows the production conditions and heat treatment conditions of each layer used in each example, and Table 7 shows the production conditions and heat treatment conditions of each layer used in each comparative example.

(Measurement of thickness)
The thickness of the outermost layer (A layer), the middle layer (B layer), and the lower layer (C layer) is the same as that of the base material that does not have the composition of the outermost layer (A layer), middle layer (B layer), and lower layer (C layer). Each was subjected to a surface treatment, and the actual thickness was measured with a fluorescent X-ray film thickness meter (SEA 5100 manufactured by Seiko Instruments, collimator 0.1 mmΦ). For example, in the case of Sn plating, if the substrate is Cu-10 mass% Sn-0.15 mass% P, the substrate has Sn, and the exact thickness of Sn plating is not known. The thickness was measured with Cu-30 mass% Zn, which does not have the composition of the substrate.

(Measurement of adhesion amount)
Each sample was acid-decomposed with sulfuric acid, nitric acid or the like, and the adhesion amount of each metal was measured by ICP (inductively coupled plasma) emission spectroscopic analysis. In addition, the acid used concretely changes with compositions which each sample has.

(Determination of composition)
Based on the measured adhesion amount, the composition of each metal was calculated.

(Determination of 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 the composition of the outermost layer (A layer), the middle layer (B layer), the lower layer (C layer), and C and O. These elements are designated elements. Further, the concentration (at%) of each element was analyzed with the total of the designated elements as 100%. The thickness in XPS (X-ray photoelectron spectroscopy) analysis corresponds to the distance on the horizontal axis of the chart by analysis (distance in terms of SiO ₂ ).
Further, the surface of the obtained sample was also subjected to qualitative analysis by survey measurement by XPS (X-ray photoelectron spectroscopy) analysis. The resolution of the qualitative analysis concentration was 0.1 at%.
As an XPS device, ULVAC-PHI Co., Ltd. 5600MC was used, ultimate vacuum: 5.7 × 10 ⁻⁹ Torr, excitation source: monochromatic AlKα, output: 210 W, detection area: 800 μmΦ, incident angle: 45 degrees, The take-off angle was 45 degrees, no neutralizing gun was used, and the measurement was performed under the following sputtering conditions.
Ion species: Ar ⁺
Acceleration voltage: 3 kV
Sweep area: 3mm x 3mm
Rate: 2.8 nm / min. (SiO ₂ equivalent)

(Evaluation)
The following evaluation was performed for each sample.
A. Insertion / extraction force The insertion / extraction force is tested by using a commercially available Sn reflow plating female terminal (090 type Sumitomo TS / Yazaki 090II series female terminal non-waterproof / F090-SMTS) with the plated male terminal according to the example and comparative example. Was evaluated by
The measuring device used for the test was a 1311NR manufactured by Aiko Engineering Co., Ltd., and the evaluation was performed with an OSPIN sliding distance of 5 mm. Since the number of samples was 5, and the insertion force was the same as the insertion force, the value obtained by averaging the maximum insertion force values of each sample was adopted. The sample of Comparative Example 1 was adopted as the blank material for the insertion / extraction force.
The target of the insertion / extraction force is less than the maximum insertion / extraction force of Comparative Example 1.
In addition, although the commercially available Sn reflow plating female terminal was used for the female terminal used for this test, when the plating or Au plating according to the example is used, the insertion / extraction force is further reduced.

B. Whisker Whisker was evaluated by a load test (ball indenter method) of JEITA RC-5241. That is, a load test was performed on each sample, and the sample after the load test was observed at a magnification of 100 to 10,000 times with a SEM (manufactured by JEOL, model JSM-5410) to observe the occurrence of whiskers. . The load test conditions are shown below.
Diameter of ball indenter: Φ1mm ± 0.1mm
Test load: 2N ± 0.2N
Test time: 120 hours Number of samples: 10
The target characteristics are that whisker generation is less than that of the current material (Comparative Example 1), and that there are two or less whiskers having a length of 20 μm or more.

C. Contact resistance The contact resistance was measured by the 4-terminal method using a contact simulator CRS-113-Au type manufactured by Yamazaki Seiki under the condition of a contact load of 50 g. The number of samples was 5, and the range from the minimum value to the maximum value of each sample was adopted. The target characteristic is a contact resistance of 10 mΩ or less.

D. Heat resistance Heat resistance was evaluated by measuring the contact resistance of a sample after an atmospheric heating (155 ° C. × 500 h) test. The target characteristic is a contact resistance of 10 mΩ or less, and the maximum target is that the contact resistance does not change before and after the heat resistance test (is equivalent).

E. Gas Corrosion Resistance Gas corrosion resistance was evaluated in the three test environments shown in the following (1) to (3). The gas corrosion resistance was evaluated by the contact resistance of the sample after the environmental tests (1) to (3) were completed. The target characteristic is a contact resistance of 10 mΩ or less, but the maximum target is that the contact resistance does not change (equivalent) before and after the heat resistance test.
(1) Salt spray test Salt concentration: 5%
Temperature: 35 ° C
Spray pressure: 98 ± 10 kPa
Exposure time: 240h
(2) Sulfurous acid gas corrosion test Sulfurous acid concentration: 25ppm
Temperature: 40 ° C
Humidity: 80% RH
Exposure time: 240h
(3) Hydrogen sulfide gas corrosion test Sulfurous acid concentration: 3ppm
Temperature: 40 ° C
Humidity: 80% RH
Exposure time: 240h

F. Solder wettability Solder wettability was evaluated for samples after plating and after a pressure cooker test (105 ° C. × 100% unsaturated RH × 96 h). Solder checker (SAT-5000 manufactured by Reska Co., Ltd.) was used, and a commercially available 25% rosin ethanol flux was used as the flux, and the solder wetting time was measured by the meniscograph method. The solder used was Sn-3Ag-0.5Cu (250 ° C.). The number of samples was 5, and the range from the minimum value to the maximum value of each sample was adopted. The target characteristic is a zero cross time of 5 seconds or less.
G. Bending workability The bending workability is the minimum bending radius (MBR) and the metal material thickness (t) at which W metal bending test is performed according to Japan Copper and Brass Association Technical Standard (JCBA) T307. The minimum bend radius ratio (MBR / t) was 3 or less, which was good. In the evaluation, the surface of the bent portion was observed with an optical microscope, and when it was judged that there was no practical problem when no crack was observed in the plating film, it was evaluated as ◯, and when the crack was recognized, it was evaluated as x. The number of samples was three.

H. Vickers hardness The Vickers hardness of the outermost layer (A layer) was measured from the surface of the sample with a load of 980.7 mN and a load holding time of 15 seconds. In addition, it measured 5 times per sample.
Further, the Vickers hardness of the lower layer (C layer) was measured by hitting a root from a section of the lower layer (C layer) with a load of 980.7 mN and a load holding time of 15 seconds.

I. Indentation Hardness The indentation hardness of the outermost layer (A layer) and the metal substrate was measured by hitting a root from the sample surface with a load of 980.7 mN and a load holding time of 15 seconds. In addition, it measured 5 times per sample.
Further, the indentation hardness of the lower layer (C layer) was measured by hitting the root with a load of 980.7 mN and a load holding time of 15 seconds from the lower layer (C layer) cross section.

J. et al. Surface Roughness Surface roughness (arithmetic average height (Ra) and maximum height (Rz)) is measured according to JIS B 0601, a non-contact type three-dimensional measuring device (manufactured by Mitaka Kogyo Co., Ltd., model NH- 3). The cut-off was 0.25 mm, the measurement length was 1.50 mm, and measurement was performed 5 times per sample.

K. Reflection density The reflection density was measured using a densitometer (ND-1, manufactured by Nippon Denshoku Industries Co., Ltd.). In addition, it measured 5 times per sample.

L. Elongation Elongation was measured by carrying out a tensile test in the rolling parallel direction of each sample according to JIS C 6511. The tensile speed was 50 mm / min. The number of samples was three.

M.M. Minimum bending radius ratio (MBR / t)
The minimum bending radius ratio was measured by the same method as bending workability, and the minimum bending radius / test specimen thickness at which no crack occurred in the material was measured. The number of samples was 5.
The evaluation result in each condition in the above test is shown to Tables 8-22.

Examples 1 to 98 were electronic component metal materials excellent in all of low insertion / removability, low whisker properties, and durability.
Comparative Example 1 is a blank material.
Comparative Example 2 was produced by thinning the Sn plating of the blank material of Comparative Example 1, but the solder wettability was poor.
Comparative Example 3 was prepared by applying Cu plating to the middle layer as compared with Comparative Example 1, but the solder wettability after the PCT test was poor.
Comparative Example 4 was produced by thinly plating the middle layer with Cu plating as compared with Comparative Example 3, but the solder wettability was poor.
Comparative Example 5 was produced without heat treatment as compared with Comparative Example 4, but the solder wettability was poor.
Comparative Example 6 was prepared by applying Cu plating to the lower layer as compared with the blank material of Comparative Example 1, but the characteristics were not different from Comparative Example 1.
Comparative Example 7 was produced by applying a lower Ni plating thicker than the blank material of Comparative Example 1, but the characteristics were not different from Comparative Example 1.
Comparative Example 8 was prepared without applying the middle layer of Ag plating as compared with Example 2, but in the depth measurement by XPS (X-ray photoelectron spectroscopy), the outermost layer (B layer) of Ag, The maximum value of the atomic concentration (at%) of Au, Pt, Pd , Rh, Os or Ir was 10 at% or less, and the solder wettability was poor.
Comparative Example 9 was prepared by thinning the outermost layer of Sn plating compared to Example 2, but the gas corrosion resistance was poor, and after the sulfurous acid gas corrosion test and after the hydrogen sulfide gas corrosion test. Contact resistance exceeded target.
Comparative Example 10 was produced by reversing the plating order of Sn and Ag as compared with Example 2, but the depth of the outermost layer (A layer) was measured by Depth measurement using XPS (X-ray photoelectron spectroscopy). Position (D ₁ ) showing the highest value of the atomic concentration (at%) of Sn or In, the highest atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer) Since the position (D ₂ ) indicating the value exists in the order of D ₂ and D ₁ , the gas corrosion resistance was poor, and the contact resistance after the hydrogen sulfide gas corrosion test exceeded the target.
In Comparative Example 11, the position (D ₁ ) showing the highest value of the atomic concentration (at%) of Sn or In of the outermost layer (A layer) in the depth measurement by XPS (X-ray photoelectron spectroscopy), the middle layer (B Since the position (D ₂ ) showing the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the layer) is D ₁ ≈D ₂ , the gas corrosion resistance is poor, The contact resistance after the hydrogen sulfide gas corrosion test exceeded the target.
Comparative Example 12 was produced by reversing the plating order of Sn and Ag as compared with Example 57, but the depth of the outermost layer (A layer) was measured by Depth measurement using XPS (X-ray photoelectron spectroscopy). Position (D ₁ ) showing the highest value of the atomic concentration (at%) of Sn or In, the highest atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the middle layer (B layer) Since the position (D ₂ ) indicating the value exists in the order of D ₂ and D ₁ , the gas corrosion resistance was poor, and the contact resistance after the hydrogen sulfide gas corrosion test exceeded the target.
In Comparative Example 13, the position (D ₁ ) showing the highest value of the atomic concentration (at%) of Sn or In in the outermost layer (A layer) in the depth measurement by XPS (X-ray photoelectron spectroscopy), the middle layer (B Since the position (D ₂ ) showing the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the layer) is D ₁ ≈D ₂ , the gas corrosion resistance is poor, The contact resistance after the hydrogen sulfide gas corrosion test exceeded the target.
Comparative Example 14 was produced without Ag plating of the middle layer (B layer) as compared with Example 78. However, in the depth measurement by XPS (X-ray photoelectron spectroscopy), the middle layer (B layer) was prepared. The maximum atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir is 10 at% or less, the gas corrosion resistance is poor, and the contact resistance after the hydrogen sulfide gas corrosion test is the target. Exceeded.

10 Metal material for electronic parts 11 Base material 12 Lower layer (C layer)
13 Middle layer (B layer)
14 Outermost layer (A layer)

Claims (41)

A substrate;
Constituting the outermost layer of the substrate, and an A layer formed of Sn, In, or an alloy thereof;
A B layer formed between Ag, Au, Pt, Pd , Rh, Os, Ir, or an alloy thereof; and a middle layer provided between the base material and the A layer;
With
The thickness of the outermost layer (A layer) is more than 0.2 μm and less than 0.6 μm ,
The alloy composition of the outermost layer (A layer) is Sn, In, or the total of Sn and In is 50% by mass or more, and the remaining alloy components are Ag, As, Au, Bi, Cd, Co, Cr, Cu, Fe, M n, becomes Mo, Ni, Pb, Sb, W, 1 kind selected from the group consisting of Zn, or a metal on the two or more kinds,
The middle layer (B layer) has a thickness of 0.001 to 0.3 μm ,
The alloy composition of the middle layer (B layer) is Ag, Au, Pt, Pd, Rh, Os, Ir, or a total of Ag, Au, Pt, Pd, Rh, Os, and Ir is 50% by mass or more, The residual alloy component is selected from the group consisting of Bi, Cd, Co, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Se, Sn, W, Tl, Zn, or two or more A metal material for electronic parts having low whisker properties and high durability made of metal. A substrate;
Constituting the outermost layer of the substrate, and an A layer formed of Sn, In, or an alloy thereof;
A B layer formed between Ag, Au, Pt, Pd , Rh, Os, Ir, or an alloy thereof; and a middle layer provided between the base material and the A layer;
With
The Sn of the surface layer (A layer), a coating weight of less than 150 [mu] g / cm ² ultra and 450 [mu] g / c m ² of In,
The alloy composition of the outermost layer (A layer) is Sn, In, or the total of Sn and In is 50% by mass or more, and the remaining alloy components are Ag, As, Au, Bi, Cd, Co, Cr, Cu, Fe, M n, becomes Mo, Ni, Pb, Sb, W, 1 kind selected from the group consisting of Zn, or a metal on the two or more kinds,
The adhesion amount of Ag, Au, Pt, Pd , Rh, Os, Ir in the middle layer (B layer) is 1 to 330 μg / cm ² ,
The alloy composition of the middle layer (B layer) is Ag, Au, Pt, Pd, Rh, Os, Ir, or a total of Ag, Au, Pt, Pd, Rh, Os, and Ir is 50% by mass or more, The residual alloy component is selected from the group consisting of Bi, Cd, Co, Cu, Fe, In, Mn, Mo, Ni, Pb, Sb, Se, Sn, W, Tl, Zn, or two or more A metal material for electronic parts having low whisker properties and high durability made of metal. The metal material for an electronic component according to claim 1 or 2 , wherein the arithmetic average height (Ra) of the surface of the outermost layer (A layer) is 0.1 µm or less and the gas corrosion resistance is more excellent. The metal material for electronic parts according to any one of claims 1 to 3 , wherein the maximum height (Rz) of the surface of the outermost layer (A layer) is 1 µm or less, and the gas corrosion resistance is more excellent. The metal material for an electronic component according to any one of claims 1 to 4 , wherein the outermost layer (A layer) has a surface reflection density of 0.3 or more, and is more excellent in gas corrosion resistance. Position (D ₁ ) indicating the highest value of the atomic concentration (at%) of Sn or In in the outermost layer (A layer) when depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the intermediate layer (B layer) The position (D ₂ ) showing the highest value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os, or Ir is present in the order of D ₁ and D ₂ from the outermost surface. 5. The metal material for electronic parts according to any one of 5 above. When depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the intermediate layer (B layer) is 10 at% or more. The metal material for electronic components according to any one of claims 1 to 6 . The metal material for electronic component according to any one of claims 1 to 7 the thickness of the middle layer (B layer) is 0.005～0.1Myuemu. The metal material for an electronic component according to any one of claims 1 to 8 , wherein an adhesion amount of Ag, Au, Pt, Pd , Rh, Os, and Ir in the intermediate layer (B layer) is 4 to 120 µg / cm ² . The metal material for an electronic component according to any one of claims 1 to 9 , wherein the substrate is a metal substrate, and a Vickers hardness of a surface of the metal substrate is Hv90 or more. The base material is a metal base material, and the hardness obtained by measuring the surface of the metal base material with a load of 980.7 mN and a load holding time of 15 seconds using an ultra-micro hardness tester. in it, the metal material for electronic component according to any one of the metal substrate according to claim 1-10 indentation hardness of the surface is not less than 1000MPa of. The base material is a metal base material, and the elongation of the metal base material measured by performing a tensile test at a tensile speed of 50 mm / min in the rolling parallel direction of the metal base material according to JIS C 2241 is 5%. The metal material for electronic parts according to any one of claims 1 to 11 , which has high bending workability as described above. The base material is a metal base material, and a minimum bending radius (MBR) and a thickness of the metal material that are subjected to a W-bend test in accordance with Japan Copper and Brass Association Technical Standard (JCBA) T307 and are not cracked. The metal material for electronic parts according to any one of claims 1 to 12 , which has high bending workability, wherein a minimum bending radius ratio (MBR / t) which is a ratio of (t) is 3 or less. The metal for electronic parts according to any one of claims 1 to 13 , wherein O is less than 50 at% when elemental analysis of the surface of the outermost layer (A layer) is performed by Survey measurement of XPS (X-ray photoelectron spectroscopy). material. A C layer formed between one or more selected from the group consisting of Ni, Cr, Mn, Fe, Co, and Cu is provided between the base material and the B layer to form a lower layer. further comprising, metal material for electronic component according to any one of claims 1-14. The composition of the alloy of the lower layer (C layer) is 50% by mass or more in total of Ni, Cr, Mn, Fe, Co, and Cu, and one selected from the group consisting of B, P, Sn, and Zn, or The metal material for an electronic component according to claim 15 , comprising two or more types. Position (D ₁ ) indicating the highest value of the atomic concentration (at%) of Sn or In in the outermost layer (A layer) when depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the intermediate layer (B layer) The position (D ₂ ) showing the highest atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir of Ni, Cr, Mn, Fe, Co or Cu in the lower layer (C layer) The metal material for an electronic component according to claim 15 or 16 , wherein a position (D ₃ ) showing the maximum value of the atomic concentration (at%) of the metal component exists in the order of D ₁ , D ₂ , D ₃ from the outermost surface. When depth analysis is performed by XPS (X-ray photoelectron spectroscopy), the maximum value of the atomic concentration (at%) of Ag, Au, Pt, Pd , Rh, Os or Ir in the intermediate layer (B layer) is 10 at% or more. there are, Ni of the lower (C layer), Cr, Mn, Fe, in any one of claims 15 to 17 atomic concentration of Co or Cu (at%) is the 50nm or more in a depth more than 25% The metal material for electronic components as described. The metal material for electronic parts according to claim 15 , wherein the lower layer (C layer) has a thickness of 0.05 μm or more. The metal material for electronic parts according to any one of claims 15 to 19 , wherein an adhesion amount of Ni, Cr, Mn, Fe, Co, and Cu in the lower layer (C layer) is 0.03 mg / cm ² or more. The metal material for electronic parts according to any one of claims 15 to 20 , wherein the surface of the lower layer (C layer) has a Vickers hardness of Hv300 or more. The Vickers hardness and thickness of the surface of the lower layer (C layer) are represented by the following formula:
Vickers hardness (Hv) ≧ −376.22 Ln (thickness μm) +86.411
The metal material for electronic components according to any one of claims 15 to 21 , which satisfies the following conditions. The lower layer (C layer), which is the hardness obtained by measuring the surface of the lower layer (C layer) with a load of 980.7 mN and a load holding time of 15 seconds using an ultra-micro hardness tester. The metal material for an electronic component according to any one of claims 15 to 22 , wherein the indentation hardness of the surface is 2500 MPa or more. The lower layer (C layer), which is the hardness obtained by measuring the surface of the lower layer (C layer) with a load of 980.7 mN and a load holding time of 15 seconds using an ultra-micro hardness tester. The indentation hardness and thickness of the surface of the following formula:
Indentation hardness (MPa) ≧ −3998.4Ln (thickness μm) +1178.9
The metal material for electronic components according to any one of claims 15 to 23 , wherein The metal material for electronic parts according to any one of claims 15 to 24 , which has high bending workability, wherein the surface of the lower layer (C layer) has a Vickers hardness of Hv1000 or less. The lower layer (C layer), which is the hardness obtained by measuring the surface of the lower layer (C layer) with a load of 980.7 mN and a load holding time of 15 seconds using an ultra-micro hardness tester. The metal material for electronic parts according to any one of claims 15 to 25 , which has a high bending workability, the indentation hardness of the surface of which is 10,000 MPa or less. When the depth analysis was performed by XPS (X-ray photoelectron spectroscopy), the position (D ₁ ) indicating the highest value of the atomic concentration (at%) of Sn or In in the outermost layer (A layer) and the lower layer (C layer) 40 at% for Ag, Au, Pt, Pd , Rh, Os, or Ir between the position (D ₃ ) where the atomic concentration (at%) of Ni, Cr, Mn, Fe, Co, Cu, or Zn is the highest. The metal material for electronic parts according to any one of claims 15 to 26 , wherein the above region is present with a thickness of 1 nm or more. Connector terminal used in the contact portions of the metal material for electronic component according to any one of claims 1 to 27. A connector using the connector terminal according to claim 28 . FFC terminal used for contact portions of metal material for electronic component according to any one of claims 1 to 27. FPC terminal using metal material for electronic component according to the contact portion in any one of claims 1 to 27. An FFC using the FFC terminal according to claim 30 . An FPC using the FPC terminal according to claim 31 . An electronic component using the metal material for an electronic component according to any one of claims 1 to 27 as an electrode for external connection. Method for producing a metal material for electronic component according to any one of claims 1 to 27 including the step of forming said outermost layer (A layer) and the middle layer (B layer), the surface treatment with the respective wet plating. 36. The method for producing a metal material for electronic components according to claim 35 , wherein the wet plating method is electroplating. Wherein the outermost layer (A layer), a manufacturing method of the metal material for electronic component according to claim 35 or 3 6 is formed by a plating treatment using an acidic plating solution. The method for producing a metal material for an electronic component according to any one of claims 35 to 37 , wherein the intermediate layer (B layer) is formed by a plating treatment using a cyan-containing plating solution. The manufacturing method of the metal material for electronic components in any one of Claims 15-27 including the process of forming the said lower layer (C layer) by the plating process using a sulfamic acid bath or a watt bath. 40. The method for producing a metal material for electronic parts according to claim 39 , wherein the plating solution used in the sulfamic acid bath and the Watt bath is a bright Ni plating solution. 41. The method for producing a metal material for electronic parts according to claim 39 or 40 , wherein the plating solution for forming the lower layer (C layer) contains saccharin as an additive.

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