JP2015042771A - Metal material for electronic component, connector terminal using the same, connector, and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal material for an electronic component which has low whisker properties and high durability.SOLUTION: The metal material for an electronic component includes: a substrate; an upper layer formed on the substrate and composed of an alloy of one or two elements selected from a constituent element group A consisting of Sn and In and one or more elements selected from a constituent element group B consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir; and an outermost layer formed on the upper layer and composed of one or two elements selected from a constituent element group C consisting of Au and Pt. The thickness of the upper layer is 0.02 to 3.00 μm inclusive, and the thickness of the outermost layer is 0.0005 μm or more and less than 0.02 μm.

Description

  The present invention relates to a metal material for electronic parts and a method for producing the same, a connector terminal using the same, a connector, and an electronic part.

  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. . In general, Sn or Sn alloy plating is required to have characteristics such as low contact resistance and high solder wettability, and more recently, a reduction in the insertion force of the plating material is also required. In addition, in Sn or Sn alloy plating, whiskers that are needle-like crystals that cause problems such as short circuits may occur on the plating surface, and it is also necessary to suppress the generation of the whiskers.

  On the other hand, Patent Document 1 discloses a contact base material, a base layer made of Ni or Co or an alloy of both formed on the surface of the contact base material, and Ag-Sn formed on the surface of the base layer. And an average concentration of Sn in the Ag—Sn alloy layer is less than 10% by mass, and the Sn concentration in the Ag—Sn alloy layer is from the interface with the underlayer to the Ag—Sn alloy layer. An electrical contact material is disclosed that varies with a concentration gradient that increases over the surface layer of the substrate. According to this, it is described that an electrical contact material having excellent wear resistance, corrosion resistance, and workability can be produced at a very low cost.

In Patent Document 2, at least the surface of the substrate made of Cu or a Cu alloy has a thickness containing an Ag ₃ Sn (ε phase) compound via an intermediate layer made of Ni or a Ni alloy layer on the surface of the substrate. A material for electric / electronic parts is disclosed, in which a surface layer composed of a Sn layer or a Sn alloy layer of 0.5 to 20 μm is formed. And according to this, the surface layer has a lower melting point than Sn, excellent solderability, no whisker, the joint strength formed after soldering is high, and at the same time the joint strength is high This is suitable as a lead material because it does not easily degrade over time, and even when used in a high temperature environment, the increase in contact resistance is suppressed, and the connection reliability with the counterpart material is not reduced. Therefore, it is described that the object is to provide a material for an electric / electronic component suitable as a contact material, a method for manufacturing the same, and an electric / electronic component using the material.

  Patent Document 3 discloses a covering material comprising a conductive base material and a coating layer formed on the base material, wherein the coating layer is an intermetallic compound of Sn and a noble metal at least on the surface side. The coating | covering material characterized by including is disclosed. According to this, a coating material having a low contact resistance, a low friction coefficient, effective in reducing the insertion force, excellent in oxidation resistance and stable over a long period of time, and its It describes that it aims to provide a manufacturing method.

  Patent Document 4 discloses a terminal / connector conductive material including a conductive base material and an Sn plating layer made of Sn or an Sn alloy formed on the base material. A coating material is disclosed in which an Ag—Sn alloy layer in which Ag—Sn fine particles are aggregated is formed on the surface. According to this, there is disclosed a terminal / connector conductive material and a fitting-type connection terminal that maintain high conductivity without being scraped even under vibration of an automobile or the like.

JP-A-4-370613 JP 11-350189 A JP 2005-126763 A JP 2010-37629 A

However, in the technique described in Patent Document 1, the relationship between the reduction in insertion force and the presence or absence of whisker generation, which have been required in recent years, has not been clarified. Moreover, since the average concentration of Sn in the Ag—Sn alloy layer is less than 10% by mass and the proportion of Ag in the Ag—Sn alloy layer is considerably large, the evaluation by the present inventors shows that chlorine gas, sulfurous acid gas, hydrogen sulfide, etc. The gas corrosion resistance to the gas was not sufficient.
Moreover, in the technique described in Patent Document 2, it is a surface layer composed of an Sn layer or Sn alloy layer having a thickness of 0.5 to 20 μm containing an Ag ₃ Sn (ε phase) compound. There was a region where the insertion force could not be lowered sufficiently with this surface layer thickness. Furthermore, it is described that the content of Ag ₃ Sn (ε phase) in the surface layer composed of the Sn layer or the Sn alloy layer is 0.5 to 5% by mass in terms of Ag, and from the Sn layer or the Sn alloy layer. In the evaluation by the present inventors, whisker was generated because the ratio of Sn in the surface layer formed was large and the thickness of the surface layer made of Sn layer or Sn alloy layer was also thick, and the resistance to fine sliding wear was not sufficient. Heat resistance and solder wettability were not sufficient.
In the technique described in Patent Document 3, the coating layer contains Sn and an intermetallic compound of noble metal, and the thickness of the Ag—Sn alloy layer containing the intermetallic compound of Sn and noble metal (Ag ₃ Sn) is Preferably they are 1 micrometer or more and 3 micrometers or less. However, according to the evaluation by the present inventors, the insertion force could not be lowered sufficiently with this thickness. Further, since this alloy layer is in a state where intermetallic compound particles are dispersed in the Sn matrix, Sn is exposed. However, this surface can corrode in corrosive environments. This leads to an increase in electrical resistance.
In the technique described in Patent Document 4, the surface is covered with fine particles of an intermetallic compound (Ag ₃ Sn) of Sn and a noble metal. However, the Sn layer is only covered with the alloy fine particles, and when viewed microscopically, the Sn layer is partially exposed. This can cause corrosion in a corrosive environment. Further, since the alloy fine particles are formed by a long-time heat treatment, the efficiency is low when a long coil is to be produced.
As described above, the metal material for electronic parts having the conventional Sn—Ag alloy / Ni base plating structure still has a problem that the insertion force cannot be sufficiently lowered and whiskers are generated. In addition, it is difficult to make the specification sufficiently satisfactory in terms of durability (heat resistance, solder wettability, fine sliding wear resistance, and gas corrosion resistance), and it has not been clarified.

  The present invention has been made in order to solve the above-described problems, and a metal material for electronic parts having a surface that is covered with a layer having low whisker properties and durability and that has high durability even in a corrosive environment. It is an object of the present invention to provide a connector terminal, a connector, and an electronic component.

  As a result of intensive studies, the present inventors have provided a metal material for electronic parts having low whisker properties and high durability by providing an upper layer and a top layer with a predetermined thickness made of a predetermined metal on a base material. It was found that it can be produced.

  The present invention completed on the basis of the above knowledge is, in one aspect, a base material and one or two selected from the group A constituent elements that are formed of Sn and In and are formed on the base material. And an upper layer made of an alloy of one or more selected from the group B element selected from the group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os and Ir, and formed on the upper layer The outermost layer is composed of one or two selected from the group consisting of Au and Pt, and the upper layer has a thickness of 0.02 μm or more and 3.00 μm or less. It is a metal material for electronic parts having a surface layer thickness of 0.0005 μm or more and less than 0.02 μm.

  In one embodiment of the metal material for electronic parts of the present invention, a region where the total concentration of Au and Pt is 50 at% or more exists from 1 nm or more from the outermost surface toward the substrate side.

  In another embodiment, the metal material for an electronic component of the present invention is selected from a group of D constituent elements that are a group consisting of Ni, Cr, Mn, Fe, Co, and Cu between the base material and the upper layer. The lower layer comprised by 1 type, or 2 or more types made is provided, and the thickness of the said lower layer is 0.02 micrometer or more and 3.00 micrometer or less.

  In yet another embodiment, the metal material for electronic component of the present invention is 1 selected from the A constituent element group, the B constituent element group, and the D constituent element group between the upper layer and the lower layer. An intermediate layer made of seeds and two or more alloys is provided, and the thickness of the intermediate layer is 0.02 μm or more and 3.00 μm or less.

  In yet another embodiment of the metal material for electronic parts according to the present invention, one or more selected from the D constituent element group are formed on the substrate, and then, from the B constituent element group. One or more selected films are formed, then one or two selected from the A constituent element group is formed, and then the A constituent element group, the B constituent element group, and the D Each element of the constituent element group is diffused, and then one or two kinds selected from the C constituent element group are formed into a film.

  In yet another embodiment of the metal material for electronic parts of the present invention, one or more selected from the D constituent element group are formed on the substrate, and then the A constituent element group is used. One or two selected films are formed, and then one or more selected from the B constituent element group is formed, and then the A constituent element group, the B constituent element group, and the D Each element of the constituent element group is diffused, and then one or two kinds selected from the C constituent element group are formed into a film.

  In still another embodiment of the metal material for electronic parts of the present invention, the diffusion is performed by heat treatment.

  In still another embodiment of the metal material for electronic parts according to the present invention, the heat treatment is performed at a temperature equal to or higher than the melting point of the metal of the A constituent element group, and the upper layer is one or two selected from the A constituent element group One or more alloy layers selected from the seed and the B constituent element group are formed.

  In another aspect, the present invention is 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 yet another aspect of the present invention, the metal material for electronic components of the present invention is provided with a female terminal connection portion on one side of a mounting portion for mounting on the housing and a substrate connection portion on the other side, and the substrate connection portion. Is an electronic component used for a press-fit terminal that is press-fitted into a through-hole formed in the substrate and attached to the substrate.

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

  Hereinafter, the metal material for electronic components according to the embodiment of the present invention will be described. As for the metal material for electronic components which concerns on embodiment of this invention, a base material, a lower layer, a middle layer, an upper layer, and the outermost layer are formed in this order. In addition, the lower layer and the middle layer are not essential components in the present invention, and the metal material for electronic components may be one in which an upper layer and an outermost layer are formed in this order on a base material.

<Configuration of metal materials for electronic parts>
(Base material)
Although it does not specifically limit as a base material, 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.

(Outermost layer)
The outermost layer is composed of one or two selected from the C constituent element group which is a group consisting of Au and Pt. Since these metals are the most chemically stable among the metals, when these metals are used for the outermost layer, it is possible to suppress deterioration of characteristics due to alteration of the upper layer or the like.
The thickness of the outermost layer needs to be 0.0005 μm or more. If the thickness of the outermost layer is less than 0.0005 μm, the durability is poor. The lower limit of the thickness of the outermost layer is more preferably 0.001 μm or more, and still more preferably 0.002 μm or more. On the other hand, there is no upper limit for the thickness of the outermost layer, but the cost increases as the thickness increases. Therefore, the upper limit is 0.02 μm. The upper limit of the thickness of the outermost layer is preferably 0.01 μm, more preferably 0.005 μm.

  It is preferable that a region having a total concentration of Au and Pt of 50 at% or more exists 1 nm or more from the outermost surface toward the substrate side. If this region is less than 1 nm, the durability may deteriorate. More preferably, it is 2 micrometers or more, More preferably, it is 3 micrometers or more.

(Upper layer)
The upper layer is one or two selected from the A constituent element group which is a group consisting of Sn and In, and the B constituent element group which is a group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os and Ir It is necessary to be comprised with the alloy with 1 type, or 2 or more types selected from.
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 the contact becomes metal-to-metal. Therefore, low contact resistance is obtained.
Sn and In are excellent in gas corrosion resistance against gases such as chlorine gas, sulfurous acid gas, and hydrogen sulfide gas. For example, when Ag that is inferior in gas corrosion resistance is used in the upper layer, the metal material for electronic parts is used. It works to improve gas corrosion resistance. 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.

  Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir are characterized by relatively heat resistance among metals. Therefore, it suppresses that the composition of a base material, a lower layer, and a middle layer diffuses to the upper layer side, and improves heat resistance. Further, these metals form a compound with Sn or In in the upper layer to suppress the formation of an oxide film of Sn or In and improve solder wettability. Among Ag, Au, Pt, Pd, Ru, 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 thickness of the upper layer needs to be 0.02 μm or more and 3.00 μm or less. When the thickness of the upper layer is less than 0.02 μm, the composition of the base material, the lower layer, and the middle layer is easily diffused to the upper layer side, and heat resistance and solder wettability are deteriorated. Further, the upper layer is worn by fine sliding, so that the base material, the lower layer and the middle layer having high contact resistance are easily exposed and the contact resistance is likely to increase. The lower limit of the upper layer thickness is more preferably 0.05 μm or more, and still more preferably 0.1 μm or more. On the other hand, when the thickness of the upper layer exceeds 3.00 μm, the insertion force increases. The upper limit of the upper layer thickness is more preferably 1.0 μm or less, and even more preferably 0.5 μm or less.

(Underlayer)
Between the base material and the upper layer, a lower layer composed of one or more selected from the D constituent element group which is a group consisting of Ni, Cr, Mn, Fe, Co and Cu is formed. It is preferable. By forming the lower layer using one or more metals selected from the D constituent element group which is a group consisting of Ni, Cr, Mn, Fe, Co and Cu, the lower layer is a constituent metal of the base material. Prevents diffusion to the upper layer and stabilizes heat resistance and solder wettability.
The thickness of the lower layer is preferably 0.02 μm or more and 3.00 μm or less. If the thickness of the lower layer is less than 0.02 μm, the constituent metal of the base material cannot be prevented from diffusing into the upper layer, and the heat resistance test and solder wettability deterioration may be suppressed. The thickness of the lower layer is more preferably 0.05 μm or more, and still more preferably 0.1 μm or more. On the other hand, when the thickness of the lower layer exceeds 3.00 μm, the insertion force increases. The thickness of the lower layer is more preferably 1.0 μm or less, and still more preferably 0.5 μm or less.
Among Ni, Cr, Mn, Fe, Co and Cu, Ni is preferable. Since Ni is hard, the insertion force is smaller than other metals. On the other hand, since Ni is a magnetic material, Cu is preferable in consideration of cost when hating magnetism.

(Middle layer)
Between the lower layer and the upper layer, there are an A constituent element group which is a group consisting of Sn and In, a B constituent element group which is a group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os and Ir, Ni, It is preferable to form an intermediate layer composed of one or two or more alloys selected from the D constituent element group which is a group consisting of Cr, Mn, Fe, Co and Cu. The presence of the middle layer prevents the constituent metals of the base material and the lower layer from diffusing into the upper layer, and suppresses heat resistance tests and solder wettability degradation.
The thickness of the middle layer is preferably 0.02 μm or more and 3.00 μm or less. If the thickness of the middle layer is less than 0.02 μm, it is not possible to prevent the constituent metals of the base material and the lower layer from diffusing into the upper layer, and the heat resistance test and solder wettability deterioration may be suppressed. The thickness of the middle layer is more preferably 0.05 μm or more, and still more preferably 0.1 μm or more. On the other hand, when the thickness of the middle layer is more than 3.00 μm, the insertion force is increased. The thickness of the middle layer is more preferably 1.0 μm or less, and still more preferably 0.5 μm or less.

(Diffusion processing)
The upper layer, the middle layer, and the lower layer are formed by depositing one or more selected from the D constituent element group on the base material, and then forming one or more selected from the B constituent element group. Then, one or two kinds selected from the A constituent element group may be formed, and each element of the A constituent element group, the B constituent element group, and the D constituent element group may be formed by diffusion. . In addition, the upper layer, the middle layer, and the lower layer are formed by depositing one or more types selected from the D constituent element group on the base material, and then forming one or two types selected from the A constituent element group. 1 type or 2 types or more selected from the B constituent element group may be formed, and each element of the A constituent element group, the B constituent element group, and the D constituent element group may be diffused. For example, when the metal of the A constituent element group is Sn and the metal of the B constituent element group is Ag, the diffusion of Ag into Sn is fast, and the Sn—Ag alloy layer is formed by natural diffusion. By forming an alloy layer, the adhesion force of Sn can be further reduced, whisker generation can be suppressed, and durability can be improved.

(Heat treatment)
The diffusion treatment may be a heat treatment. In addition, about this heat processing, process conditions (temperature x time) can be selected suitably. Further, this heat treatment is not particularly required. When heat treatment is performed, it is easier to form an alloy layer between the metal of the A constituent element group and the metal of the B constituent element group at a temperature higher than the melting point of the metal of the A constituent element group.

<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.
The metal material for electronic parts of the present invention is a through hole in which a female terminal connection portion is provided on one side of a mounting portion to be attached to a housing and a substrate connection portion is provided on the other side, and the substrate connection portion is formed on the substrate. It may be used for a press-fit terminal that is press-fitted into a board and attached to the substrate.
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, insertion force falls further by making both the male terminal and the female terminal into the metal material for electronic components of this 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.

  Hereinafter, examples, reference examples, and comparative examples of the present invention will be shown together, but these are provided for better understanding of the present invention and are not intended to limit the present invention.

  Table 1 shows the sample preparation conditions of Examples, Reference Examples, and Comparative Examples. The sample was subjected to surface treatment in the order of electrolytic degreasing, pickling, first plating, second plating, third plating, heat treatment, and fourth plating. In addition, in the production conditions of the second plating in Table 1, for example, in Example 1, the “plating condition number” is “1 + 2” and the thickness is “0.03 + 0.21 (μm)”. Shows that the second plating of Example 1 was first formed with a thickness of 0.03 μm under the plating condition 1, and then was formed with a thickness of 0.21 μm under the plating condition 2.

(Material)
Male terminal: thickness 0.64 mm, width 2.3 mm, component Cu-30Zn

(First plating condition)
(Plating condition 1) Bright Ni plating Surface treatment method: electroplating Plating solution: Ni plating solution of sulfamic acid + saccharin + additive Plating temperature: 55 ° C
Current density: 0.5-4 A / dm ²
(Plating condition 2) Cu plating Surface treatment method: electroplating Plating solution: Cu sulfate plating solution Plating temperature: 30 ° C
Current density: 0.5-4 A / dm ²
(Plating condition 3) Semi-bright Ni plating Surface treatment method: electroplating Plating solution: sulfamic acid Ni plating solution + saccharin Plating temperature: 55 ° C
Current density: 0.5-4 A / dm ²

(Second plating condition)
(Plating condition 1) Ag plating (1)
Surface treatment method: Electroplating Plating solution: Cyanide Ag plating solution (Strike bath)
Plating temperature: 30 ° C
Current density: 0.2-4 A / dm ²
(Plating condition 2) Ag plating (2)
Surface treatment method: Electroplating Plating solution: Cyanide Ag plating solution (thickening bath)
Plating temperature: 60 ° C
Current density: 0.2-4 A / dm ²
(Plating condition 3) Ag-Sn sputtering Surface treatment method: Sputtering target: Ag-Sn composition target for obtaining target composition (Plating condition 4) Sn plating Surface treatment method: electroplating Plating solution: Methanesulfonic acid Sn plating solution Plating temperature: 40 ° C
Current density: 0.5-4 A / dm ²

(Third plating condition)
(Plating condition 1) Sn plating condition Surface treatment method: Electroplating Plating solution: Methanesulfonic acid Sn plating solution Plating temperature: 40 ° C
Current density: 0.5-4 A / dm ²
(Plating condition 2) Ag plating (1)
Surface treatment method: Electroplating Plating solution: Cyanide Ag plating solution (Strike bath)
Plating temperature: 30 ° C
Current density: 0.2-4 A / dm ²
(Plating condition 3) Ag plating (2)
Surface treatment method: Electroplating Plating solution: Cyanide Ag plating solution (thickening bath)
Plating temperature: 60 ° C
Current density: 0.2-4 A / dm ²

(Heat treatment)
A sample was placed on a hot plate, and it was confirmed that the surface of the hot plate had reached a predetermined temperature, and heat treatment was performed at the temperature, time, and atmosphere described in Table 1.

(4th plating condition)
(Plating condition 1) Au plating Surface treatment method: Electroplating Plating solution: Cyan Au plating solution Plating temperature: 60 ° C
Current density: 0.5-4 A / dm ²
(Plating condition 2) Pt plating Surface treatment method: Electroplating Plating solution: Chloride bath Plating temperature: 60 ° C
Current density: 0.5-4 A / dm ²

(Determination of structure [composition] of outermost layer, upper layer, middle layer and lower layer, thickness measurement)
The structure [composition] of the outermost layer, the upper layer, the middle layer, and the lower layer and the thickness measurement were averaged by performing line analysis / point analysis by STEM (scanning electron microscope) analysis on arbitrary 10 points. In addition, the above-described STEM line analysis was performed to determine a region where the total concentration of Au and Pt was 50 at% or more from the outermost surface of the obtained sample toward the substrate side. Analysis was performed on 10 arbitrary points and averaged. The measurement results are shown in Table 2. In addition, about the measured composition, the description of "upper layer composition: Ag-Sn20" in Example 1, for example, indicates that the upper layer composition is composed of Ag containing 20 at% Sn. Further, for example, the description of “middle layer” composition: Sn—Ni30 in Example 25 indicates that it is composed of Ag containing 30 at% Ni.

(Evaluation)
The following evaluation was performed for each sample. The evaluation results are shown in Table 3.
A. Appearance Appearance was evaluated by visually and microscopically observing the sample surface after heat resistance (200 ° C. × 1000 h atmospheric heating) and after moisture resistance (60 ° C. × 90% × 1000 h). The case where there was no discoloration compared with before the test was marked with ◯, and the case where there was discoloration even partly was marked with ×.

B. Contact resistance (after plating, after heat resistance, after moisture resistance)
Contact resistance (after plating, after heat resistance, after moisture resistance) was measured by a 4-terminal method using a contact simulator CRS-113-Au type manufactured by Yamazaki Seiki Laboratories under the condition of a contact load of 10 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. The measurement was performed after plating, after heat resistance (atmospheric heating at 200 ° C. × 1000 h) and after moisture resistance (60 ° C. × 90% × 1000 h).

C. Contact resistance (after micro sliding test)
The contact resistance (after the fine sliding test) is a precision sliding test device CRS-G2050 manufactured by Yamazaki Seiki Laboratories, with a sliding distance of 0.5 mm, a sliding speed of 1 mm / s, a contact load of 1 N, and the number of sliding times. The relationship between the number of sliding and the contact resistance was evaluated under 500 reciprocating conditions. The number of samples was 5 and the range of the maximum value was adopted. The target characteristic is a contact resistance of 50 mΩ or less when the number of sliding times is 100.

D. Solder wettability The solder wettability was evaluated for samples after plating and after an unsaturated pressure cooker test (USPCT: Unsaturated Press. Test) (105 ° C. × unsaturated 100% RH × 8 h). Solder checker (manufactured by Reska Co., Ltd.) was used, and a commercially available 25% rosin methanol flux was used as the flux, and the solder wetting time was measured by the meniscograph method. As the solder, Sn-3Ag-0.5Cu (245 ° C.) was used. The number of samples was 5. The target characteristic is that the maximum zero cross time is 2 seconds or less.

E. Insertion force The insertion force was evaluated by performing insertion / extraction tests with a plated male terminal using a commercially available Sn reflow plating female terminal (090 type Sumitomo TS / Yazaki 090II series female terminal non-waterproof / F090-SMTS).
The measuring device used for the test was 1311NR made by Ikko Engineering, and the evaluation was performed with a male spin sliding distance of 5 mm. The number of samples was 5, and the insertion force was evaluated for each sample with the maximum insertion force of the sample of Comparative Example 5 being 100 (reference). The target of the insertion force is equal to or less than that of Comparative Example 5.

F. 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 characteristic is that none of the whiskers of any length will be generated.

(Evaluation results)
In Examples 1 to 33, the appearance, contact resistance, solder wettability, and insertion force were all good. There was no whisker.
In Comparative Example 1, since the thickness of the outermost Au layer is thinner than the target, the appearance after moisture resistance is poor, the contact resistance after moisture resistance is higher than the target, and the resistance after the micro-sliding test is higher than the target. It was.
In Comparative Example 2, since Au and Pt were not present in the outermost layer, the appearance after moisture resistance was poor, the contact resistance after moisture resistance was higher than the target, and the resistance after the microsliding test was higher than the target.
In Comparative Example 3, since the thickness of the upper layer was thinner than the target, the contact resistance after heat resistance was higher than the target, and the resistance after the fine sliding test was also higher than the target.
In Comparative Example 4, since the thickness of the upper layer was thicker than the target, the insertion force was higher than that of Comparative Example 5.
Comparative Example 5 is an example of a reflow Sn plating material that is a current product. The appearance after heat resistance and moisture resistance is poor, and the contact resistance after heat resistance and humidity resistance is also high. Moreover, the contact resistance after a micro sliding test is also high. Solder wettability is high after USPCT. And whiskers are also generated.
In Reference Example 1, the thickness of the lower layer is thicker than the preferred range. Therefore, the insertion force is higher than that of Comparative Example 5.
In Reference Example 2, the thickness of the middle layer is thicker than the preferred range. Therefore, the insertion force is higher than that of Comparative Example 5.

Claims (16)

A substrate;
A group consisting of Ag, Au, Pt, Pd, Ru, Rh, Os, and Ir, and one or two selected from the group consisting of Sn and In formed on the substrate. An upper layer composed of an alloy with one or more selected from the group of B constituent elements,
An outermost layer composed of one or two selected from the group consisting of C and a group consisting of Au and Pt formed on the upper layer;
The thickness of the upper layer is 0.02 μm or more and 3.00 μm or less,
A metal material for electronic parts, wherein the thickness of the outermost layer is 0.0005 μm or more and less than 0.02 μm.   2. The metal material for electronic parts according to claim 1, wherein a region in which the total concentration of Au and Pt is 50 at% or more is 1 nm or more from the outermost surface toward the substrate. Between the base material and the upper layer,
Comprising a lower layer composed of one or more selected from the group consisting of D, which is a group consisting of Ni, Cr, Mn, Fe, Co and Cu;
The metal material for electronic parts according to claim 1 or 2, wherein the lower layer has a thickness of 0.02 µm or more and 3.00 µm or less. Between the upper layer and the lower layer, an intermediate layer composed of one or more alloys selected from the A constituent element group, the B constituent element group, and the D constituent element group,
The metal material for electronic components according to claim 3, wherein the middle layer has a thickness of 0.02 μm to 3.00 μm.   Forming one or more selected from the D constituent element group on the base material, and then forming one or more selected from the B constituent element group, 1 type or 2 types selected from the A constituent element group is formed, then each element of the A constituent element group, the B constituent element group, and the D constituent element group is diffused, and then the C constituent element group The metal material for electronic components according to claim 4, wherein the metal material is formed by depositing one or two types selected from the above.   One or more selected from the D constituent element group is formed on the substrate, and then one or two selected from the A constituent element group is formed, and then the B 1 type or 2 or more types selected from the constituent element group are formed, and then each element of the A constituent element group, the B constituent element group and the D constituent element group is diffused, and then the C constituent element group The metal material for electronic components according to claim 4, wherein the metal material is formed by depositing one or two types selected from the above.   The metal material for electronic components according to claim 5 or 6, wherein the diffusion is performed by heat treatment.   The heat treatment is performed at a temperature equal to or higher than the melting point of the metal of the A constituent element group, and one or more selected from the A constituent element group and one or more selected from the B constituent element group in the upper layer The metal material for electronic components as described in any one of Claims 5-7 in which the alloy layer of this is formed.   The connector terminal which used the metal material for electronic components as described in any one of Claims 1-8 for the contact part.   A connector using the connector terminal according to claim 9.   The FFC terminal which used the metal material for electronic components as described in any one of Claims 1-8 for the contact part.   The FPC terminal which used the metal material for electronic components as described in any one of Claims 1-8 for the contact part.   An FFC using the FFC terminal according to claim 11.   An FPC using the FPC terminal according to claim 12.   The electronic component which used the metal material for electronic components as described in any one of Claims 1-8 for the electrode for external connection.   A female terminal connection part is provided on one side of a mounting part for attaching the metal material for electronic parts according to any one of claims 1 to 8 to a housing, and a board connection part is provided on the other side, respectively, and the board connection part An electronic component used for a press-fit terminal that is press-fitted into a through-hole formed in a substrate and attached to the substrate.