JP3442764B1 - Connector terminals and connectors - Google Patents

Abstract

An object of the present invention is to provide a connector terminal which is excellent in insertion / extraction property without peeling of a gold layer and has high corrosion resistance, and a connector having the same. SOLUTION: The connector terminal of the present invention is characterized in that a ruthenium layer is formed on a conductive substrate, and a gold layer is formed on the ruthenium layer. In the connector terminal of the present invention, at least one underlayer made of at least one metal selected from the group consisting of Ni, Cu, Au, and Ag is formed between the conductive substrate and the ruthenium layer. It is characterized by. And the connector of this invention has the above-mentioned connector terminal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connector widely used for connection in electric, electronic products, semiconductor products, etc., and more particularly to a connector terminal which is a contact portion thereof and a connector terminal thereof. Regarding connectors.

[0002]

2. Description of the Related Art Conventionally, various types of connectors have been used for electrical, electronic and semiconductor products. In particular, in applications where contact reliability is required, a terminal having a structure in which a Ni layer is formed on a conductive substrate and a thin gold layer is formed thereon is often used as a terminal of such a connector. It was However, in this structure, Ni
Since the hardness of both the layer and the gold layer is relatively low, there is a problem that the gold layer easily peels off when the connector is repeatedly inserted and removed. The problem is not only that the appearance is impaired, but that if the gold layer peels off and the Ni layer appears on the surface,
There has been a fatal problem that the layer is easily oxidized and the contact electric resistance (hereinafter, simply referred to as contact resistance) becomes very high. In order to solve this problem, it is possible to form a thick gold layer, but thickening the gold layer not only increases the cost, but also increases the contact friction at the time of insertion / removal of the connector and impairs the ease of insertion / removal, and the gold layer itself However, this method has not been able to solve the problem, because it becomes more prone to wear.

On the other hand, in the connector terminal having the above structure in which the Ni layer and the gold layer are formed on the conductive substrate, the Ni layer is used.
There is also a problem that a pinhole is easily generated in the layer, and the conductive substrate and the gold layer are in direct contact with each other in this pinhole, so that electrical corrosion occurs due to the difference in ionization tendency between the two.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and an object of the present invention is to prevent the gold layer from being peeled off and to be excellent in insertion / removal property and to have high corrosion resistance. An object of the present invention is to provide a provided connector terminal and a connector having the same.

[0005]

The inventors of the present invention have conducted extensive studies in order to solve the above-mentioned problems. As a result, in order to improve the insertability and the corrosion resistance while maintaining the excellent contact resistance of the gold layer, The present invention was finally completed by obtaining the knowledge that the action of the layer located under the layer is important and continuing the research based on the knowledge.

That is, the connector terminal of the present invention is characterized in that a ruthenium layer made of metal ruthenium is formed on a conductive substrate, and a gold layer is formed on the ruthenium layer. Thus from ruthenium metal
Ruthenium layer by positioning below the gold layer made of gold layer is effectively prevented from being peeled off or worn by the high hardness in which the ruthenium layer has retained the good contact resistance with gold layer It is possible to obtain excellent mating and unmating properties as it is, and to effectively prevent the occurrence of pinholes, thereby dramatically improving the corrosion resistance.

Further, the connector terminal of the present invention has an N-layered structure between the conductive substrate and the ruthenium layer made of metal ruthenium.
It is characterized in that at least one underlayer made of at least one metal selected from the group consisting of i, Cu, Au, and Ag is formed. Although the ruthenium layer has high hardness, it also has a large stress, and therefore the ruthenium layer itself may peel off depending on the type of the conductive substrate. Therefore, in order to mitigate this peeling phenomenon, a specific underlayer is provided. It was formed.

On the other hand, in the present invention, the metal ruthenium
It is characterized in that the ruthenium layer and the gold layer made of um are formed by a plating method using any one of a barrel plating apparatus, a hook plating apparatus and a continuous plating apparatus. This makes it possible to form these layers extremely efficiently.

Further, the connector of the present invention has the connector terminal described in any of the above. As a result, it is possible to obtain an extremely highly reliable connector having excellent contact resistance, insertability and corrosion resistance.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION <Conductive Substrate> The conductive substrate used in the present invention is conventionally known as a connector for connection of electric, electronic products, semiconductor products, etc. and a connection pattern on various substrates. Any conductive substrate can be used. For example, copper alloy materials such as phosphor bronze, brass, beryllium copper, iron (F
e), iron-based materials such as stainless steel, nickel-based materials, copper patterns on various substrates, and the like.

<Ruthenium Layer> The ruthenium layer of the present invention made of metal ruthenium is formed on the above-mentioned conductive substrate and is made of metal ruthenium (Ru). Usually this
Una ruthenium layer 0.05～1.5Myuemu, is preferably formed by plating a metal ruthenium on a conductive substrate as a thickness of 0.2 to 1.0 [mu] m. 0.05
When the thickness is less than μm, the effects obtained by the present invention such as improvement of the insertion / removal property cannot be sufficiently obtained, while 1.5 μm
When it exceeds m, the stress of the ruthenium layer itself becomes too large, and the ruthenium layer itself may be separated from the conductive substrate or the ruthenium layer itself may be cracked, which is not preferable.

<Gold Layer> The gold layer of the present invention is formed on the ruthenium layer and is made of metallic gold (Au). Usually, the gold layer is 0.025 to 1 μm, preferably 0.
If the thickness of 1 to 0.5 μm is metallic ruthenium
It is formed by plating on the Ranaru ruthenium layer. If it is less than 0.025 μm, excellent contact resistance due to gold may not be obtained, while if it exceeds 1 μm, the contact friction at the time of insertion / removal becomes large and the removability is impaired, which is not preferable.

<Underlayer> The underlayer of the present invention is formed as necessary when the above-mentioned ruthenium layer is easily peeled off depending on the type of the conductive substrate. Usually, the ruthenium layer hardly peels off by its own stress when the conductive substrate is made of a nickel-based material, but when the conductive substrate is made of a material other than the nickel-based material May be easily peeled off, and in such a case, it is necessary to form the underlayer. That is, the underlying layer is made of metallic ruthenium.
It has the effect of preventing peeling of the ruthenium layer composed of . Therefore, the underlayer is composed of a conductive substrate and a metal.
Between the ruthenium layer made of ruthenium (i.e., as a lower ruthenium layer) is formed, Ni, Cu, A
It is a layer made of at least one metal selected from the group consisting of u and Ag, and is formed as at least one layer (that is, as a single layer or a plurality of layers). When the underlayer is formed as a plurality of layers, the type and thickness of the metal forming each layer are determined in consideration of the thickness of the ruthenium layer made of metal ruthenium and the type of the conductive substrate. It is preferable. For example, if the conductive substrate is a copper alloy material,
Forming a first underlayer made of Ni having a thickness of 0.05 to 5 μm on a conductive substrate, and forming a second underlayer made of Au or Ag having a thickness of 0.05 to 1 μm on the first underlayer. Is preferred. When the conductive substrate is an iron-based material or brass, a first base layer made of Cu and having a thickness of 0.05 to 5 μm is formed on the conductive substrate, and a thickness of 0.05 to 5 μm is formed thereon. 2μ
It is preferable to form a second underlayer composed of m of Ni. Thus, the underlayer is usually a single layer or a plurality of layers and has a thickness of 0.05 to 7 μm, preferably 0.8 to
It can be formed by plating each metal on the conductive substrate to have a thickness of 4.0 μm. When the thickness of the underlayer is less than 0.05 μm, metal ruthenium
In some cases, it may not be possible to prevent the peeling of the ruthenium layer consisting of 2), but if it exceeds 7 μm, not only is it economically disadvantageous due to increased costs, but the thickness also changes over time and dimensional stability is lacking, as well as electrical conductivity. It is not preferable because the elasticity of the substrate itself is lost.

<Connector Terminal> The connector terminal of the present invention has a structure in which the above layers are formed on a conductive substrate. As long as it has such a structure, it does not matter whether it is a female terminal or a male terminal.

<Connector> The connector of the present invention has the above connector terminal. As long as it has such a connector terminal in terms of its structure, not only an ordinary connector but also a pattern on a circuit board, for example, is included. As described above, the connector of the present invention does not matter as to its shape, as long as it is insertable / removable and intended for electrical connection.

<Manufacturing Equipment> The ruthenium layer and the gold layer of the present invention are usually formed by a plating method as described above. Particularly, the plating apparatus is any one of a barrel plating apparatus, a hook plating apparatus and a continuous plating apparatus. It is preferable to carry out by using By using these devices, the connector terminals can be manufactured extremely efficiently. Here, the barrel plating device is
It is a device to individually plate connector terminals one by one,
The continuous plating equipment is an equipment that continuously plating a plurality of connector terminals at a time, and the hook plating equipment is located in the middle of the former two and has a medium-scale manufacturing efficiency. It is a device. These devices are well known in the plating industry, and any structure can be used as long as the structure itself is known. The underlayer of the present invention described above can also be formed by these devices.

[0017]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

<Example 1> This example relates to a connector terminal in which a ruthenium layer made of metal ruthenium and a gold layer are formed in this order on a conductive substrate. Hereinafter, description will be given with reference to FIG.

First, the conductive substrate 101 has a thickness of 0.1.
mm tape-shaped nickel was pressed into the shape of a connector, and a continuous connector terminal was cut into a length of 70 mm. After the cutting, degreasing treatment was carried out by washing with 50 g / l of an activator (trade name: Escreen 30, manufactured by Okuno Chemical Industries Co., Ltd.) at 53 ° C. for 3 minutes. After washing with water several times, 100
Using a g / l activator (trade name: NC Rustol, manufactured by Okuno Chemical Industries Co., Ltd.) at 50 ° C. for 2 minutes at a current density of 5.
The electrolytic degreasing treatment was performed by washing under the condition of 0 A / dm ² . 5% after washing with water several times
The acid activation treatment was carried out by treating with sulfuric acid of No. 1 at 25 ° C. for 1 minute, followed by washing with water several times.

Next, the conductive substrate 101 which has been subjected to the above-mentioned treatment
On the other hand, using a ruthenium plating solution (trade name: Ru-33, manufactured by NE Chemcat Co., Ltd.) having a ruthenium concentration of 8 g / l, at 60 ° C., pH 2.0 and current density of 1.5 A / dm ² . The ruthenium layer 102 made of metal Ru having a thickness of 0.4 μm was formed by electroplating for 5 minutes under a hooked plating apparatus.

After washing with water several times, rinse with 10% ammonia water (50 ° C., 5 minutes)
After that, acid activation treatment was carried out by treating with 10% hydrochloric acid at 25 ° C. for 0.5 minutes.

Then, after washing with water several times, the ruthenium layer 10 made of metal ruthenium which has been subjected to the above-mentioned treatment.
2 on top of a gold plating solution with a gold concentration of 9 g / l (trade name: N7
7, 35 by using Nchemcat Co., Ltd.
By forming a gold layer 103 made of metal Au having a thickness of 0.1 μm by electroplating with a hook plating device for 1 minute under conditions of ℃, pH 4.1, and current density of 1.2 A / dm ² . The connector terminal of the present invention shown in No. 1 was obtained.

The connector terminal thus obtained is
It has excellent contact resistance, insertability / extractability, and corrosion resistance. Therefore, the connector having this connector terminal was extremely reliable.

<Embodiment 2> In this embodiment, an underlayer, metal ruthenium, or a base layer is formed on a conductive substrate .
The present invention relates to a connector terminal in which a ruthenium layer and a gold layer are formed in this order. Hereinafter, description will be made with reference to FIG.

First, the conductive substrate 201 has a thickness of 0.1.
mm tape-shaped phosphor bronze was pressed into a connector shape, and a continuous connector terminal shape was cut into a length of 70 mm. After the cutting, degreasing treatment was carried out by washing with 50 g / l of an activator (trade name: Escreen 30, manufactured by Okuno Chemical Industries Co., Ltd.) at 53 ° C. for 3 minutes. After washing with water several times, 100
Using a g / l activator (trade name: NC Rastol, manufactured by Okuno Chemical Industries Co., Ltd.) at 50 ° C. for 2 minutes, current density 5A
The electrolytic degreasing treatment was performed by washing under the condition of / dm ² . Then, after washing with water several times, acid activation treatment was carried out by treating with 5% sulfuric acid at 25 ° C. for 1 minute, and then washing with water several times.

Next, the conductive substrate 201 which has been subjected to the above-mentioned treatment
On the other hand, a nickel plating solution (made of 240 g / l nickel sulfate, 50 g / l nickel chloride, 40 g / l boric acid) was used at 55 ° C., pH 3.8, and current density 4
An underlayer 204 made of Ni and having a thickness of 0.95 μm was formed by electroplating with a hook plating device under the condition of A / dm ² for 1 minute.

Then, after washing with water several times, a ruthenium plating solution having a ruthenium concentration of 8 g / l (trade name: Ru-33, manufactured by NE Chemcat Co., Ltd.) is formed on the underlayer 204. To form a ruthenium layer 202 having a thickness of 0.4 μm and made of metal Ru by electroplating for 5 minutes under the conditions of 60 ° C., pH 2.0, and current density of 1.5 A / dm ² using a plating machine. did.

After washing several times with water, rinsing with 50% ammonia water (50 ° C., 5 minutes)
After that, acid activation treatment was carried out by treating with 10% hydrochloric acid at 25 ° C. for 0.5 minutes.

Next, after washing with water several times, the ruthenium layer 20 made of metal ruthenium which has been subjected to the above-mentioned treatment.
2 on top of a gold plating solution with a gold concentration of 9 g / l (trade name: N7
7, 35 by using Nchemcat Co., Ltd.
By forming a gold layer 203 made of metal Au having a thickness of 0.1 μm by electroplating with a hooking plating apparatus for 1 minute under conditions of ℃, pH 4.1 and current density of 1.2 A / dm ² . The connector terminal of the present invention shown in 2 was obtained.

The connector terminal thus obtained is
It has excellent contact resistance, insertability / extractability, and corrosion resistance. Therefore, the connector having this connector terminal was extremely reliable.

Example 3 In this example, a plurality of underlayers and metal ruthenium were formed on a conductive substrate.
The present invention relates to a connector terminal in which a ruthenium layer made of um and a gold layer are formed in this order. Below, FIG.
Will be described with reference to.

First, the conductive substrate 301 has a thickness of 0.1.
mm tape-shaped brass was pressed into a connector shape, and a continuous connector terminal shape was cut into a length of 70 mm. After the cutting, degreasing treatment was carried out by washing with 50 g / l of an activator (trade name: Escreen 30, manufactured by Okuno Chemical Industries Co., Ltd.) at 53 ° C. for 3 minutes. After washing with water several times, 100
Using a g / l activator (trade name: NC Rastol, manufactured by Okuno Chemical Industries Co., Ltd.) at 50 ° C. for 2 minutes, current density 5A
The electrolytic degreasing treatment was performed by washing under the condition of / dm ² . Then, after washing with water several times, acid activation treatment was carried out by treating with 5% sulfuric acid at 25 ° C. for 1 minute, and then washing with water several times.

Next, the conductive substrate 301 which has been subjected to the above treatment
In contrast, copper sulfate plating solution (copper sulfate 90 g / l, sulfuric acid 1
30 g / l, chlorine 50 ppm and other additives) at 28 ° C., a current density of 2.5 A / dm ² , and air agitation under the conditions of air agitation to obtain an electroplating treatment by a plating apparatus. First made of Cu of 5 μm
Underlayer 304a was formed. Next, after washing with water several times, a nickel plating solution (made of 240 g / l nickel sulfate, 50 g / l nickel chloride, 40 g / l boric acid) was used on the first underlayer 304a. Second underlayer 304b made of Ni having a thickness of 1.8 μm by electroplating for 4 minutes by a hook plating apparatus under the conditions of 55 ° C., pH 3.8, and current density 4 A / dm ^2.
Was formed.

Subsequently, after washing with water several times, a ruthenium plating solution having a ruthenium concentration of 8 g / l (trade name: Ru-33, NE Chemcat Co., Ltd.) was formed on the second underlayer 304b. Manufactured by K.K.) at 60 ° C, pH 2.
0, and a current density of 1.5 A / dm ² for 5 minutes by electroplating with a hook plating apparatus to obtain a thickness of 0.
A ruthenium layer 302 made of 4 μm metal Ru was formed.

Then, after washing with water several times, further rinsing with 10% ammonia water (50 ° C., 5 minutes)
After that, acid activation treatment was carried out by treating with 10% hydrochloric acid at 25 ° C. for 0.5 minutes.

Next, after washing with water several times, the ruthenium layer 30 made of ruthenium metal which has been subjected to the above-mentioned treatment
2 on top of a gold plating solution with a gold concentration of 9 g / l (trade name: N7
7, 35 by using Nchemcat Co., Ltd.
By forming a gold layer 303 made of metal Au having a thickness of 0.1 μm by electroplating with a hooking plating apparatus for 1 minute under conditions of ℃, pH 4.1 and current density of 1.2 A / dm ² . The connector terminal of the present invention shown in No. 3 was obtained.

The connector terminal thus obtained is
It has excellent contact resistance, insertability / extractability, and corrosion resistance. Therefore, the connector having this connector terminal was extremely reliable.

<Embodiment 4> Like Embodiment 3, this embodiment relates to a connector terminal in which a plurality of base layers, a ruthenium layer made of metal ruthenium , and a gold layer are formed in this order on a conductive substrate. Is. Hereinafter, description will be made with reference to FIG.

First, the conductive substrate 301 has a thickness of 0.1.
mm tape-shaped phosphor bronze was pressed into a connector shape, and a continuous connector terminal shape was cut into a length of 70 mm. After the cutting, degreasing treatment was carried out by washing with 50 g / l of an activator (trade name: Escreen 30, manufactured by Okuno Chemical Industries Co., Ltd.) at 53 ° C. for 3 minutes. After washing with water several times, 100
Using a g / l activator (trade name: NC Rastol, manufactured by Okuno Chemical Industries Co., Ltd.) at 50 ° C. for 2 minutes, current density 5A
The electrolytic degreasing treatment was performed by washing under the condition of / dm ² . Then, after washing with water several times, acid activation treatment was carried out by treating with 5% sulfuric acid at 25 ° C. for 1 minute, and then washing with water several times.

Next, the conductive substrate 301 which has been subjected to the above treatment
On the other hand, a nickel plating solution (made of 240 g / l nickel sulfate, 50 g / l nickel chloride, 40 g / l boric acid) was used at 55 ° C., pH 3.8, and current density 4
The first underlayer 304a made of Ni and having a thickness of 1.8 μm was formed by electroplating for 4 minutes by a hook plating apparatus under the condition of A / dm ² . Then, after washing with water several times, a silver plating solution (consisting of 30 g / l of silver and 110 g / l of potassium cyanide) was used on the first underlayer 304a at 48 ° C., pH 12.9.
A thickness of 0.6 μm is obtained by electroplating with a hook plating device for 1 minute under the condition of a current density of 1.0 A / dm ^2.
The second underlayer 304b made of Ag was formed.

Subsequently, after washing with water several times, a ruthenium plating solution (trade name: Ru-33, N Chemcat Co., Ltd.) having a ruthenium concentration of 8 g / l was formed on the second underlayer 304b. Manufactured by K.K.) at 60 ° C, pH 2.
0, and a current density of 1.5 A / dm ² for 5 minutes by electroplating with a hook plating apparatus to obtain a thickness of 0.
A ruthenium layer 302 made of 4 μm metal Ru was formed.

Then, after washing with water several times, further rinsing with 10% ammonia water (50 ° C., 5 minutes)
After that, acid activation treatment was carried out by treating with 10% hydrochloric acid at 25 ° C. for 0.5 minutes.

Then, after washing with water several times, the ruthenium layer 30 made of metallic ruthenium which has been subjected to the above-mentioned treatment.
2 on top of a gold plating solution with a gold concentration of 9 g / l (trade name: N7
7, 35 by using Nchemcat Co., Ltd.
By forming a gold layer 303 made of metal Au having a thickness of 0.1 μm by electroplating with a hooking plating apparatus for 1 minute under conditions of ℃, pH 4.1 and current density of 1.2 A / dm ² . The connector terminal of the present invention shown in No. 3 was obtained.

The connector terminals thus obtained are
It has excellent contact resistance, insertability / extractability, and corrosion resistance. Therefore, the connector having this connector terminal was extremely reliable.

Comparative Example 1 A connector terminal was manufactured in the same manner as in Example 2 except that the ruthenium layer made of metal ruthenium was not formed in Example 2. Such a connector terminal has a structure in which a Ni layer and a gold layer are formed in this order on a conductive substrate, and corresponds to a conventional connector terminal.

<Hardness Test> Using the connector terminals obtained in Examples 1 to 4 and the connector terminal obtained in Comparative Example 1, a surface hardness tester (device name: Vickus type surface hardness tester,
Using Akashi Seisakusho Co., Ltd., measuring load 10g
The surface hardness of each of the lower Au layers was measured.
The results are shown in Table 1 below.

<Corrosion Resistance Test> Using the connector terminals obtained in Examples 1 to 4 and the connector terminal obtained in Comparative Example 1, the respective corrosion resistances were measured. The measurement conditions were performed by spraying 5% saline and observing the degree of corrosion after 8 hours at 35 ° C. Then, those that did not corrode were evaluated as “◯”, those that slightly corroded were evaluated as “Δ”, and those that significantly corroded were evaluated as “x”. The evaluation results are shown in Table 1 below.

[0048]

[Table 1]

As is clear from Table 1, the connector terminals of the respective examples have an excellent surface hardness as compared with the connector terminal of Comparative Example 1 and are therefore excellent in that no peeling of the gold layer occurs at all. In addition to the excellent mating and unmating properties, the corrosion resistance test also showed excellent corrosion resistance. In addition,
The variation in the surface hardness of each example is observed in the case of the ruthenium layer consisting of metal ruthenium alone.
Although the surface hardness of 00~850HV is shown, metal Le
Since the ruthenium layer made of ruthenium is relatively thin, it is considered that the influence of the conductive substrate and the underlayer existing as the lower layer of the layer appears.

The embodiments and examples disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0051]

The connector terminal of the present invention has an excellent surface hardness due to the formation of a ruthenium layer made of metal ruthenium as a lower layer of the gold layer, so that the gold layer is not worn or peeled off. It is possible to obtain excellent insertion / removal properties while effectively preventing and maintaining the excellent contact resistance of the gold layer, and to effectively prevent the occurrence of pinholes, thereby dramatically improving the corrosion resistance. In addition, metal Le
By forming an underlayer as a lower layer of a ruthenium layer made of ruthenium, metal ruthenium
It is possible to effectively prevent peeling of the ruthenium layer made of um . Further, if these ruthenium layers and gold layers are formed by a plating method using either a barrel plating device, a hook plating device or a continuous plating device,
It becomes possible to form these layers extremely efficiently. Therefore, the connector having the connector terminal of the present invention directly follows the unique advantages of such a connector terminal, and has excellent contact resistance, insertability and detachability,
It has corrosion resistance and is extremely reliable.
Therefore, the connector of the present invention can be widely used for connecting electric, electronic products, semiconductor products and the like.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a connector terminal in which a ruthenium layer made of metal ruthenium and a gold layer are formed in this order on a conductive substrate.

[FIG. 2] Underlayer on the conductive substrate, from ruthenium metal
Ruthenium layer made, is a schematic sectional view of a gold layer, respectively connector terminal is formed in this order.

FIG. 3 shows a plurality of underlayers and metallic ruthenium on a conductive substrate.
Ruthenium layer made of beam, which is a schematic cross-sectional view of a gold layer, respectively connector terminal is formed in this order.

[Explanation of symbols]

101, 201, 301 conductive substrate, 102, 20
Ruthenium layer composed of 2,302 metal ruthenium , 1
03,203,303 Gold layer, 204 Underlayer, 304
a first underlayer, 304b second underlayer.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01R 13/03 C25D 5/10 C25D 7/00

Claims (4)

(57) [Claims] 1. A connector terminal comprising a ruthenium layer made of metal ruthenium formed on a conductive substrate, and a gold layer formed on the ruthenium layer. 2. An underlayer made of at least one metal selected from the group consisting of Ni, Cu, Au and Ag is provided between the conductive substrate and the ruthenium layer made of metal ruthenium. The connector terminal according to claim 1, wherein the connector terminal is formed. 3. The ruthenium layer and the gold layer made of metal ruthenium are formed by a plating method using any one of a barrel plating apparatus, a hook plating apparatus and a continuous plating apparatus. Connector terminal shown. 4. A connector having the connector terminal according to claim 1.