JP2006183068A - Conductive material for connecting part and method for manufacturing the conductive material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive material for a fitting terminal which has a low friction coefficient (low insertion force), and can maintain low contact resistance even in high temperature, corrosion, and vibration environments. <P>SOLUTION: The conductive material has a Cu-Sn alloy covering layer which contains a Cu of 20 to 70at% and has an average thickness of 0.2 to 3.0 m, and an Sn covering layer having an average thickness of 0.2 to 5.0 μm formed formed in this order on the surface of a base material composed of a Cu plate strip. The material surface is subjected to reflow processing, wherein the arithmetic average roughness Ra at least on one direction is 0.15μm or more, the arithmetic average roughness Ra in all the directions is 3.0 μm or less, and a part of the Cu-Sn alloy covering layer is exposed from the surface of the Sn covering layer, wherein an exposing area rate of the material surface is 3 to 75%. The conductive material is manufactured by applying reflow processing after forming an Ni plating layer, and further, a Cu plating layer and an Sn plating layer as needed on the roughened base material surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to conductive materials for connecting parts such as connector terminals and bus bars used mainly in electrical wiring of automobiles and consumer devices, and in particular, friction and wear during insertion and extraction of male terminals and female terminals and in use. The present invention relates to a conductive material for a fitting-type connecting part that is required to have a reliable electrical connection.

  It is important that conductive materials for connecting parts such as connector terminals and bus bars used to connect electrical wiring of automobiles / consumer equipment require high electrical connection reliability for low-level signal voltages and currents. Except in the case of a simple electric circuit, Cu or Cu alloy subjected to Sn plating (including Sn alloy plating such as solder plating) is used. Sn plating is widely used for reasons such as low cost compared to Au plating and other surface treatments. Among them, Sn plating not containing Pb, especially whisker, is being used in order to meet recent environmental load substance regulations. Reflow Sn plating and molten Sn plating, which have almost no reports of short circuit faults due to the occurrence of the above, have become mainstream.

  In recent years, the progress of electronics has been remarkable. For example, in automobiles, advanced electronic components are rapidly progressing from the pursuit of safety, environment and comfort. As a result, the number of circuits, weight, etc. will increase, resulting in an increase in consumption space and energy consumption. Therefore, connection parts such as connector terminals will be multipolarized, reduced in size and weight, and installed in the engine room. However, there is a demand for a conductive material for connecting parts that can satisfy the performance as a connecting part.

  The main purpose of applying Sn plating to the conductive material for connecting parts is to obtain a low contact resistance at the electrical contact portion and the joint, and to provide corrosion resistance to the surface, and to solder the joint for the connecting component. It is to obtain the solderability. Sn plating is a very soft conductive film, and its surface oxide film is easily destroyed. Therefore, for example, in a fitting type terminal composed of a combination of a male terminal and a female terminal, electrical contact portions such as indents and ribs are easy to form a gastight contact by adhesion between platings, and are suitable for obtaining a low contact resistance. . Further, in order to maintain a low contact resistance during use, it is preferable that the thickness of the Sn plating is thick, and it is also important to increase the contact pressure for pressing the electrical contact portions.

  However, increasing the thickness of the Sn plating and increasing the contact pressure that presses the electrical contact portions increases the contact area between the Sn plating and the adhesion force. This increases the shear resistance that shears deformation resistance and adhesion, resulting in increased insertion force. A fitting-type connecting component having a large insertion force can reduce the efficiency of assembly work or cause electrical connection deterioration due to a fitting error. For this reason, even if the number of poles increases, a terminal having a low insertion force is required so that the entire insertion force does not become larger than the conventional one.

  Furthermore, it is difficult to maintain a low contact resistance in subsequent use, such as small Sn-plated terminals with reduced contact pressure that presses the electrical contact portions together in order to reduce the insertion force and wear during insertion / extraction. In addition to this, the electrical contact portion is slightly slid due to vibration or thermal expansion / contraction during use, and it is easy to cause a fine sliding wear phenomenon in which the contact resistance is abnormally increased. The fine sliding wear phenomenon is caused by the Sn plating of the electrical contact portion being worn by fine sliding, and the resulting Sn oxide being deposited in a large amount between the electrical contact portions due to repeated fine sliding. It is believed that. Therefore, even if the number of insertions / extractions is increased, and even if a slight sliding occurs in the Sn plating of the electrical contact part, the insertion / removal wear resistance and fine resistance can be maintained with a low insertion force so that low contact resistance can be maintained. There is a demand for terminals that are excellent in sliding wear.

  In the following Patent Documents 1 to 6, a Ni underplating layer is formed on the surface of the Cu or Cu alloy base material as necessary, and a Cu plating layer and an Sn plating layer are formed thereon in this order, followed by a reflow treatment. In addition, a fitting-type terminal material in which a Cu—Sn alloy coating layer mainly composed of a Cu 6 Sn 5 phase is formed is described. According to these descriptions, the Cu—Sn alloy layer formed by the reflow process is harder than Ni plating or Cu plating, and it exists as an underlayer of the Sn layer remaining on the outermost surface. The force can be reduced. Moreover, a low contact resistance can be maintained by the Sn layer on the surface.

JP 2004-68026 A JP 2003-151668 A JP 2002-298963 A JP 2002-226882 A JP-A-11-135226 Japanese Patent Laid-Open No. 10-60666

  Further, in the following Patent Documents 7 to 9, a Cu base plating layer is formed on the surface of the Cu or Cu alloy base material as necessary, a Sn plating layer is formed, and then a heat treatment is performed after a reflow treatment as necessary. , A fitting type terminal material in which an intermetallic compound layer mainly composed of Cu—Sn and, if necessary, an oxide film layer is formed in this order is described. According to these descriptions, the insertion force of the terminal can be further reduced by forming the Cu—Sn alloy layer on the surface by heat treatment.

JP 2000-226645 A JP 2000-212720 A Japanese Patent Laid-Open No. 10-25562

  The insertion force of the terminal in which the Cu—Sn alloy layer is formed on the base of the Sn layer decreases as the surface Sn layer becomes thinner. Furthermore, the insertion force of the terminal having the Cu—Sn alloy layer formed on the surface is further reduced. On the other hand, when the thickness of the Sn layer is reduced, there is a problem that the contact resistance of the terminal increases when the Sn layer is kept in a high temperature atmosphere as high as 150 ° C. for example for an automobile engine room for a long time. Further, when the Sn layer is thin, the corrosion resistance and solderability are also lowered. In addition, the Sn layer tends to cause a fine sliding wear phenomenon. Thus, in this type of terminal, the insertion force is very low, after many insertions / removals, after holding in a high temperature atmosphere for a long time, maintenance of low contact resistance in corrosive environment or vibration environment, etc. However, the characteristics required for this are still not sufficiently obtained, and further improvements are required.

  Therefore, the present invention provides a conductive material for connecting parts in which a Cu-Sn alloy coating layer and a Sn coating layer are formed on the surface of a base material made of a Cu plate, and has a low friction coefficient (low insertion force) and at the same time electrical connection. It is an object of the present invention to obtain a conductive material for connecting parts that can maintain reliability (low contact resistance).

The inventors of the present invention have a Ni coating layer (if necessary), a Cu coating layer (if necessary), a Cu—Sn alloy coating layer, and a Sn coating layer in this order on the surface of the base material made of Cu strip. The Cu—Sn alloy coating layer is formed with a material surface exposed area ratio of 3 to 75% (desirably, an average material surface exposure interval in at least one direction is 0.01 to 0.5 mm), and an average thickness is Invented a conductive material for connecting parts having a thickness of 0.1 to 3.0 μm, a Cu content of 20 to 70 at%, and an average thickness of the Sn coating layer of 0.2 to 5.0 μm. A patent application was filed (Japanese Patent Application No. 2004-264749). In the prior invention, the surface roughness (desirably, the average interval between the irregularities in at least one direction) is the arithmetic average roughness Ra in at least one direction is 0.15 μm or more and the arithmetic average roughness Ra in all directions is 4.0 μm or less. After using a base material having Sm of 0.01 to 0.5 mm and forming Cu plating (if necessary) and Sn plating on the surface of the base material, or forming Ni plating, Cu plating and Sn plating A reflow process is performed.
The present invention is a further development of this prior invention.

The conductive material for connecting parts according to the present invention is a Cu-Sn alloy coating layer having a Cu content of 20 to 70 at% and an average thickness of 0.2 to 3.0 [mu] m on the surface of a base material made of Cu strips. Sn coating layer having an average thickness of 0.2 to 5.0 μm is formed in this order, and the material surface is reflow-treated, and arithmetic average roughness Ra in at least one direction is 0.15 μm or more and all Arithmetic average roughness Ra in the direction is 3.0 μm or less, part of the Cu—Sn alloy coating layer is exposed on the surface of the Sn coating layer, and the material surface exposure of the Cu—Sn alloy coating layer The area ratio is 3 to 75%. A part of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer protrudes from the surface of the Sn coating layer. In addition, the area | region in which this coating layer structure was formed may extend to the single side | surface or both surfaces of a preform | base_material, and may occupy only a part of single side | surface or both surfaces.
In this conductive material for connecting parts, it is desirable that the material surface has an average material surface exposure interval of 0.01 to 0.5 mm in at least one direction.
Furthermore, in this conductive material for connecting parts, it is desirable that the thickness of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer (thickness of the exposed portion) is 0.2 μm or more.

In the conductive material for connecting parts, a Cu coating layer may be further provided between the surface of the base material and the Cu-Sn alloy coating layer.
Further, a Ni coating layer may be further formed between the surface of the base material and the Cu—Sn alloy coating layer. In this case, a Cu coating layer may be further provided between the Ni coating layer and the Cu—Sn alloy coating layer.
In the present invention, the Cu strip includes a Cu alloy strip. In addition, the Sn coating layer, the Cu coating layer, and the Ni coating layer include Sn alloy, Cu alloy, and Ni alloy in addition to Sn, Cu, and Ni metal, respectively.

The conductive material for connecting parts is formed by forming a Cu plating layer and a Sn plating layer in this order on the surface of a base material made of a Cu plate, and then performing a reflow process to form a Cu-Sn alloy coating layer and a Sn coating layer. It is manufactured by forming in this order. In the production method of the present invention, the arithmetic average roughness Ra in at least one direction is 0.3 μm or more and the arithmetic average roughness Ra in all directions is 4.0 μm or less per surface of the base material. There is a feature in the point. The Sn plating layer is melted and fluidized and smoothed by a reflow process, and a part of the Cu—Sn alloy coating layer is exposed on the surface of the Sn coating layer at the convex and concave portions formed on the base material. At that time, an appropriate Sn plating layer thickness is selected according to the surface roughness of the base material, and the material surface after the reflow treatment has an arithmetic average roughness Ra in at least one direction of 0.15 μm or more in all directions. The arithmetic average roughness Ra is 3.0 μm or less, and the material surface exposed area ratio of the Cu—Sn alloy coating layer is 3 to 75%. At this time, a part of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer protrudes from the surface of the Sn coating layer.
As for the surface roughness of the base material, the average interval Sm of unevenness calculated in the one direction (average value of intervals of one mountain valley period obtained from the intersection where the roughness curve intersects the average line) is 0.01 to It is desirable to be 0.5 mm. Further, the reflow treatment is performed at a temperature not lower than the melting point of the Sn plating layer and not higher than 600 ° C. so that the thickness of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer is 0.2 μm or more. It is desirable to perform for 3 to 30 seconds.
Note that, in the surface of the base material, the region where the coating layer configuration is formed by the surface roughness may extend over one or both sides of the base material, or occupy only a part of one side or both sides. May be.

The Cu-Sn alloy coating layer is formed by inter-diffusion of Cu and Sn in the Cu plating layer and the Sn plating layer by reflow treatment, and in this case, the Cu plating layer is completely extinguished and partially remains. There can be both cases. Depending on the thickness of the Cu plating layer, Cu may also be supplied from the base material. The average thickness of the Cu plating layer formed on the surface of the base material is preferably 1.5 μm or less, and the average thickness of the Sn plating layer is preferably in the range of 0.4 to 8.0 μm. The average thickness of the Cu plating layer is preferably 0.1 μm or more.
In the manufacturing method, a Cu plating layer may not be formed at all. In this case, Cu of the Cu—Sn alloy coating layer is supplied from the base material.
In the manufacturing method, a Ni plating layer may be formed between the base material surface and the Cu plating layer. The average thickness of the Ni plating layer is 3 μm or less, and the average thickness of the Cu plating layer in this case is preferably 0.1 to 1.5 μm.
In addition, in this invention, Cu plating layer, Sn plating layer, and Ni plating layer contain Cu alloy, Sn alloy, and Ni alloy other than Cu, Sn, and Ni metal, respectively.

Since the conductive material for connecting parts according to the present invention can keep the coefficient of friction low, particularly for fitting type terminals, for example, when used for multipolar connectors in automobiles, The insertion force is low and assembly work can be performed efficiently. Moreover, even if it is kept for a long time in a high temperature atmosphere, it can maintain electrical reliability (low contact resistance) even in a corrosive environment or in a vibration environment. Even when it is placed in a place where it is used at a very high temperature, such as an engine room, it is possible to maintain even better electrical reliability.
In addition, when using the electrically-conductive material for connection components which concerns on this invention as a fitting type terminal, although using for both a male and a female terminal is desirable, it can also be used for only one of a male and a female terminal.

Hereinafter, the conductive material for connecting parts according to the present invention will be specifically described.
(1) Regarding the Cu—Sn alloy coating layer, the reason for setting its Cu content to 20 to 70 at% will be described. The Cu—Sn alloy coating layer having a Cu content of 20 to 70 at% is made of an intermetallic compound mainly composed of a Cu 6 Sn 5 phase. The Cu6Sn5 phase is very hard compared to Sn or Sn alloy forming the Sn coating layer. If it is partially exposed on the outermost surface of the material, deformation resistance and adhesion due to digging of the Sn coating layer during terminal insertion / extraction The shear resistance for shearing can be suppressed, and the friction coefficient can be made extremely low. Furthermore, in the present invention, the Cu6Sn5 phase partially protrudes from the surface of the Sn coating layer, so that the contact pressure is a hard Cu6Sn5 phase when the electrical contact part slides or slides slightly under terminal insertion / extraction or vibration environment. Accordingly, the contact area between the Sn coating layers can be further reduced, so that the friction coefficient can be further reduced, and wear and oxidation of the Sn coating layer due to fine sliding are also reduced. On the other hand, the Cu3Sn phase is harder but has a higher Cu content than the Cu6Sn5 phase. Therefore, when this is partially exposed on the surface of the Sn coating layer, the oxidation of Cu on the surface of the material due to aging, corrosion, etc. The amount of material increases, the contact resistance tends to increase, and it becomes difficult to maintain the reliability of electrical connection. Further, since the Cu3Sn phase is more fragile than the Cu6Sn5 phase, there is a problem that molding processability is inferior. Therefore, the constituent component of the Cu—Sn alloy coating layer is defined as a Cu—Sn alloy having a Cu content of 20 to 70 at%.
This Cu—Sn alloy coating layer may contain a part of the Cu 3 Sn phase, and may contain a base material, component elements during Sn plating, and the like. However, if the Cu content of the Cu—Sn alloy coating layer is less than 20 at%, the adhesion force increases and it is difficult to lower the friction coefficient, and the fine sliding wear resistance also decreases. On the other hand, if the Cu content exceeds 70 at%, it becomes difficult to maintain the reliability of electrical connection due to aging or corrosion, and the moldability and the like also deteriorate. Therefore, the Cu content of the Cu—Sn alloy coating layer is regulated to 20 to 70 at%. More desirably, it is 45 to 65 at%.

(2) The reason for setting the average thickness of the Cu—Sn alloy coating layer to 0.2 to 3.0 μm will be described. In the present invention, the average thickness of the Cu—Sn alloy coating layer, the surface density of Sn contained in the Cu—Sn alloy coating layer (unit: g / mm 2), and the Sn density (unit: g / mm 3) (The method for measuring the average thickness of the Cu—Sn alloy coating layer described in the following examples is based on this definition). When the average thickness of the Cu—Sn alloy coating layer is less than 0.2 μm, particularly when the Cu—Sn alloy coating layer is partially exposed on the surface of the material as in the present invention, thermal diffusion such as high-temperature oxidation is performed. As a result, the amount of Cu oxide on the surface of the material increases, the contact resistance tends to increase, and it becomes difficult to maintain the reliability of electrical connection. On the other hand, when it exceeds 3.0 μm, it is economically disadvantageous, the productivity is poor, and the hard layer is formed thick, so that the moldability is also deteriorated. Therefore, the average thickness of the Cu—Sn alloy coating layer is specified to be 0.2 to 3.0 μm. More desirably, the thickness is 0.3 to 1.0 μm.

(3) The reason why the material surface exposed area ratio of the Cu—Sn alloy coating layer is set to 3 to 75% will be described. In the present invention, the material surface exposed area ratio of the Cu—Sn alloy coating layer is calculated as a value obtained by multiplying the surface area of the Cu—Sn alloy coating layer exposed per unit surface area of the material by 100. If the exposed surface area ratio of the Cu—Sn alloy coating layer is less than 3%, the amount of adhesion between the Sn coating layers increases, and the contact area during terminal insertion / extraction increases, making it difficult to reduce the friction coefficient. Also, the fine sliding wear resistance is lowered. On the other hand, if it exceeds 75%, the amount of Cu oxide on the surface of the material due to aging or corrosion increases, and it is easy to increase the contact resistance, and it becomes difficult to maintain the reliability of electrical connection. Therefore, the material surface exposed area ratio of the Cu—Sn alloy coating layer is specified to be 3 to 75%. More desirably, it is 10 to 50%.

(4) The reason why the average thickness of the Sn coating layer is 0.2 to 5.0 μm will be described. In the present invention, the average thickness of the Sn coating layer is a value obtained by dividing the surface density (unit: g / mm2) of Sn contained in the Sn coating layer by the density of Sn (unit: g / mm3). (The method for measuring the average thickness of the Sn coating layer described in the examples below is based on this definition). If the average thickness of the Sn coating layer is less than 0.2 μm, the amount of Cu oxide on the surface of the material due to thermal diffusion such as high-temperature oxidation increases, and the contact resistance is likely to increase, and the corrosion resistance also deteriorates. It becomes difficult to maintain the reliability of the connection. On the other hand, if it exceeds 5.0 μm, it is economically disadvantageous and the productivity is also deteriorated. Therefore, the average thickness of the Sn coating layer is specified to be 0.2 to 5.0 μm. More desirably, the thickness is 0.5 to 3.0 μm.
When the Sn coating layer is made of an Sn alloy, examples of the constituent components other than Sn of the Sn alloy include Pb, Bi, Zn, Ag, and Cu. Pb is preferably less than 50% by mass, and other elements are preferably less than 10% by mass.

(5) The reason why the arithmetic average roughness Ra in at least one direction of the material surface is 0.15 μm or more and the arithmetic average roughness Ra in all directions is 3.0 μm or less will be described. When the arithmetic average roughness Ra is less than 0.15 μm in all directions, the protrusion height of the material surface of the Cu—Sn alloy coating layer is low overall, and the contact pressure is reduced when the electric contact portion slides or slightly slides. The ratio received by the hard Cu6Sn5 phase becomes small, and in particular, it becomes difficult to reduce the amount of wear of the Sn coating layer due to fine sliding. On the other hand, when the arithmetic average roughness Ra exceeds 3.0 μm in any direction, the amount of Cu oxide on the surface of the material due to thermal diffusion such as high-temperature oxidation increases, and the contact resistance is likely to increase, and the corrosion resistance also deteriorates. For this reason, it becomes difficult to maintain the reliability of the electrical connection. Accordingly, the surface roughness of the base material is defined such that the arithmetic average roughness Ra in at least one direction is 0.15 μm or more and the arithmetic average roughness Ra in all directions is 3.0 μm or less. More desirably, the thickness is 0.2 to 2.0 μm.

(6) The reason why the average material surface exposure interval in at least one direction of the material surface is 0.01 to 0.5 mm will be described. In the present invention, the average material surface exposure interval of the Cu—Sn alloy coating layer is defined as the average width (length along the straight line) of the Cu—Sn alloy coating layer crossing the straight line drawn on the material surface and Sn. It is defined as the value obtained by adding the average width of the covering layer. When the average material surface exposure interval of the Cu—Sn alloy coating layer is less than 0.01 mm, the amount of Cu oxide on the material surface due to thermal diffusion such as high-temperature oxidation increases, and it is easy to increase the contact resistance, and the reliability of electrical connection It becomes difficult to maintain the sex. On the other hand, when it exceeds 0.5 mm, it may be difficult to obtain a low coefficient of friction particularly when used for a small terminal. In general, when the terminal is reduced in size, the contact area of an electrical contact portion (insertion / extraction portion) such as an indent or a rib is reduced, so that the contact probability of only the Sn coating layers increases during insertion / extraction. This increases the amount of adhesion and makes it difficult to obtain a low coefficient of friction. Therefore, it is desirable that the average material surface exposure interval of the Cu—Sn alloy coating layer be 0.01 to 0.5 mm in at least one direction. More desirably, the average material surface exposure interval of the Cu—Sn alloy coating layer is set to 0.01 to 0.5 mm in all directions. Thereby, the contact probability only of Sn coating layers in the case of insertion / extraction falls. More desirably, the thickness is 0.05 to 0.3 mm.

(7) The reason why the thickness of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer is 0.2 μm or more will be described. This is because when the Cu-Sn alloy coating layer is partially exposed on the surface of the Sn coating layer as in the present invention, the thickness of the Cu-Sn alloy coating layer exposed on the surface of the Sn coating layer depends on the manufacturing conditions. It is because the case where it becomes very thin compared with the average thickness of a Cu-Sn alloy coating layer arises. In the present invention, the thickness of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer is defined as a value measured by cross-sectional observation (what is the average thickness measurement method for the Cu—Sn alloy coating layer)? Different). When the thickness of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer is less than 0.2 μm, particularly when the Cu—Sn alloy coating layer is partially exposed on the surface of the material as in the present invention. Since the amount of Cu oxide on the material surface due to thermal diffusion such as high-temperature oxidation increases and the corrosion resistance also decreases, it is easy to increase the contact resistance and it is difficult to maintain the reliability of electrical connection. Therefore, the thickness of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer is desirably 0.2 μm or more. More desirably, it is 0.3 μm or more.

(8) When using a Zn-containing Cu alloy such as brass or red brass as a base material, a Cu coating layer may be provided between the base material and the Cu—Sn alloy coating layer. This Cu coating layer is a layer in which the Cu plating layer remains after the reflow treatment. It is widely known that the Cu coating layer is useful for suppressing the diffusion of Zn and other base material constituent elements to the material surface, and improves the solderability. If the Cu coating layer becomes too thick, the moldability and the like deteriorate and the economic efficiency also deteriorates. Therefore, the thickness of the Cu coating layer is preferably 3.0 μm or less.
A small amount of component elements contained in the base material may be mixed in the Cu coating layer. Moreover, when Cu covering layer consists of Cu alloy, Sn, Zn, etc. are mentioned as structural components other than Cn of Cn alloy. In the case of Sn, less than 50% by mass, and for other elements, less than 5% by mass is desirable.

(9) Further, a Ni coating layer may be formed between the base material and the Cu—Sn alloy coating layer (when there is no Cu coating layer), or between the base material and the Cu coating layer. The Ni coating layer suppresses the diffusion of Cu and matrix constituent elements to the surface of the material, suppresses the increase in contact resistance even after use at high temperature for a long time, and suppresses the growth of the Cu—Sn alloy coating layer to provide the Sn coating. It is known that layer consumption is prevented and sulfurous acid corrosion resistance is improved. Further, the diffusion of the Ni coating layer itself onto the material surface is suppressed by the Cu—Sn alloy coating layer or the Cu coating layer. For this reason, the connecting component material on which the Ni coating layer is formed is particularly suitable for connecting components that require heat resistance. If the Ni coating layer becomes too thick, the moldability and the like deteriorate and the economic efficiency also deteriorates. Therefore, the thickness of the Ni coating layer is preferably 3.0 μm or less.
The Ni coating layer may contain a small amount of component elements contained in the base material. Moreover, when Ni coating layer consists of Ni alloy, Cu, P, Co etc. are mentioned as structural components other than Ni of Ni alloy. For Cu, 40% by mass or less, and for P and Co, 10% by mass or less are desirable.

(10) Since the unevenness on the surface of the Sn coating layer on the surface of the material of the present invention may reduce the surface gloss and adversely affect the friction coefficient and contact resistance, it is desirable that the surface is as smooth as possible. As a method for smoothing the surface of the Sn coating layer coated with a material having a rough surface of the base material, a mechanical method for grinding or polishing after forming the coating layer, or a method for reflowing the Sn coating layer However, in consideration of economy and productivity, a method of reflowing the Sn coating layer is desirable. Further, as in the present invention, in order to form a part of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer, it is very difficult to manufacture by a method other than the reflow treatment.
When the Sn plating layer is applied directly on the surface of the base material with severe irregularities or through the Ni plating layer or the Cu plating layer, if the uniform electrodeposition of plating is good, the Sn plating layer surface is Reflecting the surface form, a highly uneven surface is obtained. When this is subjected to reflow treatment, the surface of the Sn coating layer can be smoothed by the action of the molten Sn of the surface convex portion flowing into the surface concave portion, and one of the Cu-Sn alloy coating layers formed during the reflow treatment. The portion can be exposed on the surface of the Sn coating layer. Moreover, whisker resistance is also improved by performing the heat melting treatment. The Cu—Sn diffusion alloy layer formed between the Cu plating layer and the molten Sn plating layer usually grows reflecting the surface form of the base material. However, if the reflow treatment conditions are inappropriate, the thickness of the Cu—Sn alloy coating layer protruding from the surface of the Sn coating layer may be extremely thin compared to the average thickness of the Cu—Sn alloy coating layer. .

Next, the method for producing the conductive material for connection parts according to the present invention will be specifically described.
(1) In the conductive material for connecting parts of the present invention, the Sn coating layer after the reflow treatment exists with an average thickness of 0.2 to 5.0 μm, and the arithmetic average roughness Ra in at least one direction of the material surface is 0. .15 μm or more, arithmetic average roughness Ra in all directions is 3.0 μm or less, a part of the Cu—Sn alloy coating layer is exposed on the surface of the Sn coating layer, and the surface exposed area ratio is 3 to 75%. is there. A part of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer protrudes on the surface of the Sn coating layer. In the conventional conductive material for connecting parts, if the Cu—Sn alloy coating layer is exposed on the surface, the Sn coating layer is completely or almost extinguished.

The method of the present invention is a method in which the surface of the base material is roughened, and then the Sn plating layer is applied directly to the surface of the base material or through the Ni plating layer or the Cu plating layer, followed by reflow processing. is there. As a method for roughening the surface of the base material, a physical method such as ion etching, a chemical method such as etching or electrolytic polishing, rolling (using a work roll roughened by polishing or shot blasting), polishing, etc. And mechanical methods such as shot blasting. Among these methods, rolling and polishing are desirable as methods that are excellent in productivity, economy, and reproducibility of the base material surface form.
In addition, when the Ni plating layer, the Cu plating layer, and the Sn plating layer are respectively made of a Ni alloy, a Cu alloy, and a Sn alloy, it is possible to use the respective alloys described above regarding the Ni coating layer, the Cu coating layer, and the Sn coating layer. it can.

(2) Here, regarding the surface roughness of the base material, the reason why the arithmetic average roughness Ra in at least one direction is 0.3 μm or more and the arithmetic average roughness Ra in all directions is 4.0 μm or less will be described. When the arithmetic average roughness Ra is less than 0.3 μm in all directions, it is very difficult to manufacture the conductive material for connecting parts of the present invention. Specifically, the arithmetic average roughness Ra in at least one direction of the material surface after the reflow treatment is 0.15 μm or more, and the material surface exposed area ratio of the Cu—Sn alloy coating layer is 3 to 75%, At the same time, it becomes very difficult to set the average thickness of the Sn coating layer to 0.2 to 5.0 μm. On the other hand, when the arithmetic average roughness Ra exceeds 4.0 μm in any direction, it becomes difficult to smooth the surface of the Sn coating layer due to the flow action of molten Sn or Sn alloy. Therefore, the surface roughness of the base material is defined such that the arithmetic average roughness Ra in at least one direction is 0.3 μm or more and the arithmetic average roughness Ra in all directions is 4.0 μm or less. Due to the surface roughness, a part of the Cu—Sn alloy coating layer grown by the reflow process is exposed on the material surface with the flow action of the molten Sn or Sn alloy (smoothing of the Sn coating layer).
Regarding the surface roughness of the base material, it is more desirable that the arithmetic average roughness Ra in at least one direction is 0.4 μm or more and the arithmetic average roughness Ra in all directions is 3.0 μm or less.

(3) Further, the reason why the average interval Sm between the irregularities calculated in the one direction is set to 0.01 to 0.5 mm for the surface roughness of the base material will be described. The method of the present invention is a method in which the surface of the base material is roughened, and then the Sn plating layer is applied directly to the surface of the base material or through the Ni plating layer or the Cu plating layer, followed by reflow processing. In addition, the material surface preferably has an average material surface exposure interval of 0.01 to 0.5 mm in at least one direction. Since the Cu-Sn diffusion alloy layer formed between the Cu alloy base material or the Cu plating layer and the molten Sn plating layer normally grows reflecting the surface form of the base material, the material surface exposure interval is the base material. This is reflected in the average interval Sm of the unevenness on the material surface. Therefore, it is desirable that the average interval Sm between the irregularities calculated in the one direction is 0.01 to 0.5 mm. More desirably, the thickness is 0.05 to 0.3 mm. This makes it possible to control the exposed form of the Cu—Sn alloy coating layer exposed on the material surface.

(4) Moreover, the reflow conditions in the case of performing the reflow treatment are the melting temperature of the Sn plating layer to 600 ° C. × 3 to 30 seconds. In the case of Sn metal, when the heating temperature is less than 230 ° C., it does not melt, and in order to obtain a Cu-Sn alloy coating layer with a Cu content that is not too low, it is desirably 240 ° C. or higher. Softening and distortion occur, and a Cu-Sn alloy coating layer with an excessively high Cu content is formed, and the contact resistance cannot be kept low. If the heating time is less than 3 seconds, the heat transfer becomes non-uniform, and a sufficiently thick Cu—Sn alloy coating layer cannot be formed. If the heating time exceeds 30 seconds, the surface of the material oxidizes and the contact resistance increases. In addition, the fine sliding wear resistance also deteriorates.
By performing this reflow treatment, a Cu—Sn alloy coating layer is formed, the molten Sn or Sn alloy flows, the Sn coating layer is smoothed, and a Cu—Sn alloy coating layer having a thickness of 0.2 μm or more Is exposed on the material surface. Further, the plating particles become large, the plating stress is reduced, and whiskers are not generated. In any case, in order to uniformly grow the Cu—Sn alloy layer, it is desirable to perform the heat treatment at the temperature at which Sn or the Sn alloy melts and with as little heat as possible at 300 ° C. or less.

(5) Until now, regarding the method for producing a conductive material according to the present invention, an Sn plating layer is formed in this order directly on a base material or via a Ni plating layer or a Cu plating layer, and then subjected to reflow treatment to form Cu. Although the method of forming a Sn alloy layer and further smoothing the surface of the material has been described, the coating layer structure of the conductive material for connecting parts according to the present invention can be formed directly on the base material or via a Ni plating layer. It can also be obtained by forming a Sn alloy plating layer, forming a Sn plating layer thereon, and performing a reflow treatment. The latter method is also included in the present invention.

  The cross-sectional structure (after reflow) of the conductive material for connecting parts according to the present invention described above is schematically shown in FIG. In FIG. 1, one surface of the base material A (upper surface in FIG. 1) is roughened, and the other surface is smooth as in the conventional material. On the roughened one surface, a Cu—Sn alloy coating layer Y composed of particles having a diameter of several to several tens of μm is formed along the unevenness of the surface, and the Sn coating layer X melts and flows smoothly. Accordingly, a part of the Cu—Sn alloy coating layer Y is exposed on the surface of the material and protrudes from the surface of the Sn coating layer X. On the other smooth surface, the Sn coating layer X covers the entire surface of the Cu—Sn alloy coating layer Y as in the conventional material.

As described above, the conductive material for connecting parts of the present invention has relatively good electrical connection reliability even when the Sn coating layer necessary for maintaining the reliability of the electrical connection is formed thick, and the insertion / extraction of the terminals. The Cu-Sn alloy coating layer, which is effective in reducing the insertion / extraction force at the time, is exposed to the material surface under appropriate conditions, so that the friction coefficient is low and the reliability of electrical connection (low contact resistance) is achieved. Can be maintained.
Further, this conductive material for connecting parts is a Cu layer having a Cu content of 20 to 70 at% and an average thickness of 0.2 to 3.0 μm, at least in the covering layer structure where the terminal is inserted / extracted and slightly slid A Sn alloy coating layer and an Sn coating layer having an average thickness of 0.2 to 5.0 μm are formed in this order, the material surface is reflowed, and the arithmetic average roughness Ra in at least one direction is 0. 15 μm or more, the arithmetic average roughness Ra in all directions is 3.0 μm or less, and a part of the Cu—Sn alloy coating layer is exposed on the surface of the Sn coating layer, and the Cu—Sn alloy is formed. It is sufficient that the material surface exposed area ratio of the coating layer is 3 to 75%, and the configuration of the coating layer of the portion where the terminal is not inserted / extracted (for example, a joint portion with a wire or a printed board) does not satisfy the above-mentioned regulations. Good. However, if this conductive material for connecting parts is applied to a portion where the terminal is not inserted / extracted, the reliability of electrical connection can be further increased.

  The following examples will focus on the essential points and will be described more specifically, but the present invention is not limited to these examples.

[Preparation of Cu alloy base material]
In this example, a Cu alloy strip containing 0.1% by mass of Fe, 0.03% by mass of P, and 2.0% by mass of Sn in Cu is used, and a mechanical method (rolling or polishing) is used. ), And a Cu alloy base material having a surface roughness of Vickers hardness of 180 and a thickness of 0.25 mm was obtained. Furthermore, after performing Ni plating of each thickness, Cu plating, and Sn plating, by performing the reflow process for 10 seconds at 280 degreeC, test material No. 1-5 were obtained. The production conditions are shown in Table 1. In addition, the surface roughness of the Cu alloy base material described in Table 1, the average thickness of Ni plating, Cu plating, and Sn plating were measured as follows.
[Method for measuring surface roughness of Cu alloy base material]
It measured based on JISB0601-1994 using the contact-type surface roughness meter (Tokyo Seimitsu; Surfcom 1400). The surface roughness measurement conditions were a cutoff value of 0.8 mm, a reference length of 0.8 mm, an evaluation length of 4.0 mm, a measurement speed of 0.3 mm / s, and a stylus tip radius of 5 μmR. The surface roughness measurement direction was a direction perpendicular to the rolling or polishing direction performed during the surface roughening treatment (the direction in which the surface roughness is maximized).

[Measurement method of average thickness of Ni plating]
The average thickness of the Ni plating of the test material before the reflow treatment was calculated using a fluorescent X-ray film thickness meter (Seiko Instruments Inc .; SFT3200). The measurement conditions were Sn / Ni / base metal two-layer calibration curve for the calibration curve and the collimator diameter was φ0.5 mm.
[Measuring method of average thickness of Cu plating]
The cross section of the test material before reflow processing processed by the microtome method was observed at a magnification of 10,000 using an SEM (scanning electron microscope), and the average thickness of Cu plating was calculated by image analysis processing.
[Method for measuring average thickness of Sn plating]
Using a fluorescent X-ray film thickness meter (Seiko Instruments Inc .; SFT3200), the average thickness of the Sn plating of the test material before the reflow treatment was calculated. The measurement conditions were a single layer calibration curve of Sn / base material or a two-layer calibration curve of Sn / Ni / base material for the calibration curve, and the collimator diameter was φ0.5 mm.

Then, the coating layer structure and material surface roughness of the obtained test material are shown in Table 2. In addition, the Cu content of the Cu—Sn alloy coating layer, the average thickness of the Cu—Sn alloy coating layer, the average thickness of the Sn coating layer, the material surface exposed area ratio of the Cu—Sn alloy coating layer, Cu—Sn The average material surface exposure interval of the alloy coating layer, the thickness of the Cu—Sn alloy coating layer exposed on the material surface, and the material surface roughness were measured as follows.
[Method for measuring Cu content of Cu-Sn alloy coating layer]
First, the test material was immersed in an aqueous solution containing p-nitrophenol and caustic soda as components for 10 minutes to remove the Sn coating layer. Thereafter, the Cu content of the Cu—Sn alloy coating layer was determined by quantitative analysis using EDX (energy dispersive X-ray spectrometer).
[Method for measuring average thickness of Cu-Sn alloy coating layer]
First, the test material was immersed in an aqueous solution containing p-nitrophenol and caustic soda as components for 10 minutes to remove the Sn coating layer. Thereafter, the film thickness of the Sn component contained in the Cu—Sn alloy coating layer was measured using a fluorescent X-ray film thickness meter (Seiko Instruments Inc .; SFT3200). The measurement conditions were a single layer calibration curve of Sn / base material or a two-layer calibration curve of Sn / Ni / base material for the calibration curve, and the collimator diameter was φ0.5 mm. The obtained value was defined as the average thickness of the Cu—Sn alloy coating layer.

[Method for measuring average thickness of Sn coating layer]
First, the sum of the film thickness of the Sn coating layer of the test material and the film thickness of the Sn component contained in the Cu—Sn alloy coating layer was measured using a fluorescent X-ray film thickness meter (Seiko Instruments Inc .; SFT3200). . Then, it was immersed for 10 minutes in the aqueous solution which uses p-nitrophenol and caustic soda as components, and the Sn coating layer was removed. Again, the film thickness of the Sn component contained in the Cu—Sn alloy coating layer was measured using a fluorescent X-ray film thickness meter. The measurement conditions were a single layer calibration curve of Sn / base material or a two-layer calibration curve of Sn / Ni / base material for the calibration curve, and the collimator diameter was φ0.5 mm. By subtracting the film thickness of the Sn component contained in the Cu-Sn alloy coating layer from the sum of the film thickness of the obtained Sn coating layer and the film thickness of the Sn component contained in the Cu-Sn alloy coating layer, Sn The average thickness of the coating layer was calculated.

[Measuring Method of Material Surface Exposed Area Ratio of Cu—Sn Alloy Coating Layer]
The surface of the test material was observed at a magnification of 200 using an SEM (scanning electron microscope) equipped with EDX (energy dispersive X-ray spectrometer), and the resulting composition image was shaded (dirt, scratches, etc.). The surface area area ratio of the Cu—Sn alloy coating layer was measured by image analysis. In FIG. No. 1 composition image, No. 1 in FIG. 2 shows a composition image. In the figure, X is a Sn coating layer, and Y is an exposed Cu—Sn alloy coating layer. In addition, No. No. 1 is a surface roughening treatment by polishing. No. 2 performs surface roughening treatment by rolling.
[Measuring method of average material surface exposure interval of Cu—Sn alloy coating layer]
The surface of the test material was observed at a magnification of 200 times using an SEM (scanning electron microscope) equipped with EDX (energy dispersive X-ray spectrometer), and was drawn on the material surface from the obtained composition image. By calculating the average of the value obtained by adding the average width (length along the straight line) of the Cu—Sn alloy coating layer crossing the straight line and the average width of the Sn coating layer, the average of the Cu—Sn alloy coating layer is obtained. The material surface exposure interval was measured. The measurement direction (the direction of the drawn straight line) was a direction perpendicular to the rolling or polishing direction performed during the surface roughening treatment.
[Method for measuring thickness of Cu—Sn alloy coating layer exposed on material surface]
The cross section of the test material processed by the microtome method is observed at a magnification of 10,000 times using a SEM (scanning electron microscope), and the thickness of the Cu-Sn alloy coating layer exposed on the material surface is determined by image analysis processing. Calculated.

[Material surface roughness measurement method]
It measured based on JISB0601-1994 using the contact-type surface roughness meter (Tokyo Seimitsu; Surfcom 1400). The surface roughness measurement conditions were a cutoff value of 0.8 mm, a reference length of 0.8 mm, an evaluation length of 4.0 mm, a measurement speed of 0.3 mm / s, and a stylus tip radius of 5 μmR. The surface roughness measurement direction was a direction perpendicular to the rolling or polishing direction performed during the surface roughening treatment (the direction in which the surface roughness is maximized).

Moreover, about the obtained test material, the friction coefficient evaluation test, the contact resistance evaluation test after leaving at high temperature, the contact resistance evaluation test after spraying with salt water, and the contact resistance evaluation test at the time of fine sliding were performed as follows. The results are shown in Table 3.
[Friction coefficient evaluation test]
The shape of the indented portion of the electrical contact in the fitting type connecting part was simulated and evaluated using an apparatus as shown in FIG. First, a male test piece 1 of a plate material cut out from each test material (No. 1 to 5) is fixed to a horizontal base 2, and the test material No. The covering layers were brought into contact with each other by placing a female test piece 3 of a hemispherical work piece cut out from 5 (with an inner diameter of φ1.5 mm). Subsequently, the male test piece 1 is pressed by applying a load of 3.0 N (weight 4) to the female test piece 3 and using a horizontal load measuring instrument (Iko Engineering Co., Ltd .; Model-2152). The sample was pulled in the horizontal direction (sliding speed was 80 mm / min), and the maximum frictional force F (unit: N) up to a sliding distance of 5 mm was measured. The coefficient of friction was determined by the following formula (1). In addition, 5 is a load cell and the arrow is a sliding direction.
Friction coefficient = F / 3.0 (1)

[Evaluation test for contact resistance after standing at high temperature]
Each test material was heat-treated at 160 ° C. for 120 hours in the air, and then contact resistance was measured by a four-terminal method under an open voltage of 20 mV, a current of 10 mA, and no sliding.
[Contact resistance test after spraying with salt water]
Each test material was subjected to a salt spray test of 35 ° C. × 6 hr using a 5% NaCl aqueous solution based on JIS Z2371-2000, and then contact resistance was measured by a four-terminal method using an open-circuit voltage of 20 mV, a current of 10 mA, and nothing. Measurement was performed under sliding conditions.

[Evaluation test for contact resistance during fine sliding]
The shape of the indented portion of the electrical contact in the fitting type connecting part was simulated and evaluated using a sliding tester (Yamazaki Seiki Laboratory Co., Ltd .; CRS-B1050CHO) as shown in FIG. First, test material No. A male test piece 6 of a plate material cut out from 5 is fixed to a horizontal base 7, and a female test of a hemispherical work material (with an inner diameter of φ1.5 mm) cut out from each test material (No. 1 to 5) thereon The coating layers were brought into contact with each other with the piece 8 interposed therebetween. Subsequently, a load of 2.0 N (weight 9) is applied to the female test piece 8 to hold the male test piece 6, a constant current is applied between the male test piece 6 and the female test piece 8, and the stepping motor 10 is used. Then, the male test piece 6 is slid in the horizontal direction (sliding distance is 50 μm, sliding frequency is 1 Hz), and the maximum contact resistance up to 1000 times of sliding is determined by the four-terminal method with an open voltage of 20 mV and a current of 10 mA. The measurement was performed under the following conditions. The arrow indicates the sliding direction.

As shown in Tables 1-3, no. Nos. 1 and 2 satisfy the requirements stipulated in the present invention regarding the coating layer structure, have a very low friction coefficient, contact resistance after standing at high temperature for a long time, contact resistance after spraying with salt water, and contact resistance at the time of fine sliding Also exhibits excellent properties. In particular, no. No. 1 has particularly low heat resistance after being left at high temperature and is excellent in heat resistance.
On the other hand, no. 3 has a large average protrusion interval of the Cu-Sn alloy coating layer protruding on the material surface, so that the effect of reducing the friction coefficient at a small contact is small, and the contact resistance at the time of fine sliding is sufficiently suppressed. could not. No. In No. 4, since the arithmetic average roughness Ra of the material surface was small, the contact resistance during fine sliding could not be suppressed low. In addition, No. No. 5 uses a normal base material that is not subjected to roughening treatment, so that the Cu—Sn alloy coating layer is not exposed on the material surface, has a high friction coefficient, and has a high contact resistance during fine sliding.

[Preparation of Cu alloy base material]
In this example, a 7/3 brass strip is used, and a surface roughening treatment is performed by a mechanical method (rolling or polishing), and a predetermined surface roughness is obtained with a Vickers hardness of 170 and a thickness of 0.25 mm. It finished to the Cu alloy base material which has. Further, after each thickness of Ni plating, Cu plating, and predetermined Sn plating was applied, each reflow treatment was performed, whereby the test material No. 6-10 were obtained. The production conditions are shown in Table 4. In addition, about the surface roughness of Ni alloy base material described in Table 4, Ni plating, Cu plating, and the average thickness of Sn plating, it measured in the same way as the said Example 1.

  Then, the coating layer structure and material surface roughness of the obtained test material are shown in Table 5. In addition, the Cu content of the Cu—Sn alloy coating layer, the average thickness of the Cu—Sn alloy coating layer, the average thickness of the Sn coating layer, the material surface exposed area ratio of the Cu—Sn alloy coating layer, Cu—Sn The average material surface exposure interval of the alloy coating layer, the thickness of the Cu—Sn alloy coating layer exposed on the material surface, and the material surface roughness were measured in the same manner as in Example 1.

  For the obtained test materials, the friction coefficient evaluation test, the contact resistance evaluation test after standing at high temperature, the contact resistance evaluation test after spraying with salt water, and the contact resistance evaluation test at the time of fine sliding are the same as in Example 1 above. I went there. The results are shown in Table 6.

As shown in Tables 4-6, no. No. 6 satisfies the requirements stipulated in the present invention with respect to the coating layer configuration, has a very low coefficient of friction, and has any contact resistance after standing at high temperature for a long time, contact resistance after spraying salt water, and contact resistance at the time of fine sliding. Show excellent properties.
On the other hand, no. 7 is a test material subjected to reflow treatment at a high temperature for a short time, and the exposed portion of the Cu-Sn alloy coating layer protruding on the material surface is thin, so that the contact resistance after being left at high temperature for a long time The contact resistance after spraying with salt water increased. No. In No. 8, since the reflow temperature was low, the Cu content of the Cu—Sn alloy coating layer was decreased, the effect of reducing the friction coefficient was small, and the contact resistance during fine sliding was also increased. Conversely, no. No. 9 was subjected to reflow treatment at a temperature that was too high, so the Cu content of the Cu—Sn alloy coating layer increased, and the contact resistance after standing at high temperature for a long time and the contact resistance after spraying with salt water increased. Furthermore, no. No. 10 has a very long reflow time, the Sn coating layer is reduced, the surface area area ratio of the Cu-Sn alloy coating layer is increased, and the Sn oxide film layer is formed thick during the reflow process. The contact resistance after leaving for a long time, the contact resistance after spraying with salt water, and the contact resistance at the time of fine sliding increased.

It is a conceptual diagram which shows typically the cross-section of the electrically-conductive material for connection components which concerns on this invention. Example No. It is a scanning electron microscope composition image of the outermost surface structure of 1 specimen. Example No. It is a scanning electron microscope composition image of the outermost surface structure of 2 specimens. It is a conceptual diagram of a friction coefficient measuring jig. It is a conceptual diagram of a fine sliding wear measuring jig.

Explanation of symbols

A Base material X Sn coating layer Y Cu-Sn alloy coating layer 1 Male test piece 2 units 3 Female test piece 4 Weight 5 Load cell 6 Male test piece 7 units 8 Female test piece 9 Weight 10 Stepping motor

Claims (13)

A Cu-Sn alloy coating layer having a Cu content of 20 to 70 at% and an average thickness of 0.2 to 3.0 [mu] m and an average thickness of 0.2 to 5 are formed on the surface of the base material made of Cu strips. A 0.0 μm thick Sn coating layer was formed in this order, the material surface was reflowed, the arithmetic average roughness Ra in at least one direction was 0.15 μm or more, and the arithmetic average roughness Ra in all directions was 3. 0 μm or less, part of the Cu—Sn alloy coating layer is exposed on the surface of the Sn coating layer, and the material surface exposed area ratio of the Cu—Sn alloy coating layer is 3 to 75%. A conductive material for connecting parts. 2. The conductive material for connection parts according to claim 1, wherein an average material surface exposure interval in at least one direction of the material surface is 0.01 to 0.5 mm. 3. The conductive material for connection parts according to claim 1, wherein the thickness of the Cu—Sn alloy coating layer exposed on the surface of the Sn coating layer is 0.2 μm or more. The conductive material for connection parts according to any one of claims 1 to 3, further comprising a Cu coating layer between a surface of the base material and the Cu-Sn alloy coating layer. The conductive material for connection parts according to any one of claims 1 to 3, wherein a Ni coating layer is further formed between the surface of the base material and the Cu-Sn alloy coating layer. The conductive material for connecting parts according to claim 5, further comprising a Cu coating layer between the Ni coating layer and the Cu—Sn alloy coating layer. The surface of the base material has an arithmetic average roughness Ra in at least one direction of 0.3 μm or more and an arithmetic average roughness Ra in all directions of 4.0 μm or less. The conductive material for connection parts described in any one. The conductive material for connecting parts according to claim 7, wherein the surface of the base material has an average interval Sm of unevenness in at least one direction of 0.01 to 0.5 mm. After forming a Cu plating layer and a Sn plating layer in this order on the surface of the base material made of Cu plate strip, a reflow process is performed to form a Cu—Sn alloy coating layer and a Sn coating layer in this order. In the material manufacturing method, the surface of the base material has an arithmetic average roughness Ra in at least one direction of 0.3 μm or more and an arithmetic average roughness Ra in all directions of 4.0 μm or less, and contains Cu. The Cu—Sn alloy coating layer having an amount of 20 to 70 at% and an average thickness of 0.2 to 3.0 μm, and the Sn coating layer having an average thickness of 0.2 to 5.0 μm are formed. The surface of the material after the reflow treatment has an arithmetic average roughness Ra in at least one direction of 0.15 μm or more and an arithmetic average roughness Ra in all directions of 3.0 μm or less. -Sn alloy coating Exposing a portion of the layer, the manufacturing method of the Cu-Sn connecting parts conductive material the material surface exposed area of the alloy coating layer, characterized in that a 3-75%. The method for producing a conductive material for connection parts according to claim 9, wherein a Ni plating layer is formed between the surface of the base material and the Cu plating layer. In the method for manufacturing a conductive material for connecting parts, in which a Sn plating layer is formed on the surface of a base material made of a Cu strip, and then a reflow process is performed to form a Cu-Sn alloy coating layer and a Sn coating layer in this order. The surface of the base material has an arithmetic average roughness Ra of 0.3 μm or more in at least one direction and an arithmetic average roughness Ra in all directions of 4.0 μm or less, and the Cu content is 20 to 70 at%. And the Cu—Sn alloy coating layer having an average thickness of 0.2 to 3.0 μm and the Sn coating layer having an average thickness of 0.2 to 5.0 μm, and a material after reflow treatment The surface has an arithmetic average roughness Ra in at least one direction of 0.15 μm or more and an arithmetic average roughness Ra in all directions of 3.0 μm or less. The surface of the Sn coating layer is formed of the Cu—Sn alloy coating layer. Expose part of it, Method for producing a connection component conductive material, characterized in that the material surface exposed area ratio of the serial Cu-Sn alloy coating layer and 3 to 75%. The surface of the base material has a surface roughness with an average interval Sm of irregularities in at least one direction of 0.01 to 0.5 mm. Material manufacturing method. The method for producing a conductive material for connection parts according to any one of claims 9 to 12, wherein the reflow treatment is performed at a temperature of not lower than the melting point of the Sn plating layer and not higher than 600 ° C for 3 to 30 seconds.

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