JP4368931B2 - Male terminal and manufacturing method thereof - Google Patents

Description

  The present invention relates to a male terminal having a soldering portion and a fitting portion and a manufacturing method thereof, and more particularly to a male terminal suitable for use in a connector having a large number of cores and a manufacturing method thereof. More particularly, the present invention relates to a male terminal suitable for use in an automobile connector and a method for manufacturing the same.

  Some male terminals, which are metal parts used in connectors for electronic devices, have one end soldered to a printed circuit board or the like and the other end connected to a female terminal. For example, a rod-shaped male terminal that relays a printed circuit board and a wire harness used in an automobile has one end called a fitting portion and a function to fit a female terminal, and the other end called a soldering portion. And has the function of being soldered.

  In this case, the fitting portion is required to have a low contact resistance in order to ensure stable electrical contact with the female terminal. Moreover, it is also required that insertion / extraction is easy. Since the soldering portion is soldered to the printed circuit board, it is required that the solderability is good. In particular, when it is planned to be used in a high temperature environment such as for automobiles, or stored for a long time in a warehouse even before soldering, or left at the bottom of a ship for a long time for import and export. Therefore, there is a strong demand for heat resistance capable of maintaining the above characteristics even at high temperatures.

  In general, copper or copper alloy is used as the material for the male terminal in terms of conductivity and cost, and copper or nickel is used as the base plating for the surface to satisfy the above required characteristics, and as the finish plating. Two-layer plating to which reflow Sn is applied is industrially performed.

  In recent years, the number of cores of the connector has increased with the progress of the electrification of automobiles, and since some of them have more than 100 cores, a small insertion / extraction force is particularly required, With the conventional plating configuration, it is becoming difficult to satisfy the required characteristics for male terminals that are becoming stricter year by year. That is, since Sn is a soft metal, the friction at the time of terminal fitting connection is large. For this reason, when the number of cores of the connector is significantly increased, a strong insertion / extraction force is required. In order to reduce the insertion / extraction force, the reflow Sn plating thickness may be reduced. However, when the reflow Sn plating thickness is reduced, the surface Sn is alloyed with Cu as the raw material or Ni and Cu as the base plating in a high temperature environment. As a result, Sn does not remain on the surface layer, and solderability and contact resistance are deteriorated.

In view of this, Japanese Patent Application Laid-Open No. 2005-307240 (Patent Document 1) proposes three-layer plating in which the Sn plating thickness is changed depending on the part in order to solve the above-described problems. That is, a partial region of a material made of copper or a copper alloy was covered with a Sn plating thin layer having a thickness of 0.05 μm or more and less than 0.8 μm, and the remaining region was integrally formed with a thickness of 0.8 μm or more and 3 μm or less. Provided is a conductive material that is covered with a Sn plating thick layer, and has a base layer formed of a Ni plating layer and a Cu plating layer from the material side as the Sn plating thin layer and the base layer of the Sn plating thick layer. (Claim 1). The conductive material is obtained by performing electroplating in a plating bath by using the material having the base layer as a cathode and disposing an insulating shielding plate in a part between the cathode and the anode facing the cathode. The Sn plating thin layer having a thickness of 0.05 μm or more and less than 0.8 μm is coated on a partial area on the cathode, and the Sn plating thick layer integrally formed with a thickness of 0.8 μm or more and 3 μm or less is formed on the remaining area. Manufactured by a coating method (claim 6).
JP 2005-307240 A

The three-layer plating generally has a structure as shown in FIG. 2, and Ni and Cu are sequentially plated on the surface of the base material, Sn plating is performed on the surface layer, and then reflow treatment is performed. Due to proper management of plating thickness and reflow treatment, most of Cu plating becomes an intermetallic compound with Sn.
Therefore, the reaction between Sn and Cu on the surface layer is almost completed after the reflow treatment, and even if heated after that, the Sn—Cu intermetallic compound hardly grows, and the Sn thickness of the surface layer is maintained. Further, the Sn—Cu intermetallic compound also acts as a barrier for suppressing the surface Sn from reacting with the base Ni to form an intermetallic compound.

  Here, the male terminal is produced by punching a flat metal material, but it has been mainly produced by punching from a strip material obtained by applying Sn plating to a copper alloy such as brass. (Two side plating). When the Sn-plated material is punched, the metal material is exposed at the press fracture surface. For soldering electronic materials, metals with higher melting points than Sn-Pb alloys such as Sn have been used by making Pb-free from conventional Sn-Pb alloys, but the metal materials are exposed at the press fracture surface. As a result, soldering defects may occur in these high melting point brazing materials. For this reason, many methods have recently been selected for plating on the entire surface including the press fracture surface after pressing. However, there is a problem that uniform plating thickness control is difficult when full plating is performed after pressing, and in the case of three-layer plating, the difficulty of plating thickness control is further increased.

The above problems will be described in detail below. The general width of each part of the male terminal is the following dimensions, but when plating after processing into the terminal form, if the terminal shape is, for example, a rod shape, the both ends of the terminal due to the effect of current concentration during plating It is inevitable that the plating thickness is increased. This tendency becomes more prominent as the terminal width is thinner and the terminal length is longer, and the plating thickness at the tip may be as much as five times that of the normal part.
Terminal length: 15-80mm
(Example: 32mm)
Terminal thickness: 0.4 to 1.0 mm
(Example: 0.64mm)
Soldering part: Width 0.4-1.0mm
(Example: 0.64mm)
Mating part: Width 0.5-5.0mm
(Example: 0.64mm, 1.0mm, 2.3mm)

The presence of such plating thickness distribution further reduces the effect of the three-layer plating.
That is, when the intermediate Cu plating thickness is increased at the tip of the terminal, a large amount of Cu that has not formed an intermetallic compound with Sn after the reflow treatment remains, so that the reaction with Sn proceeds with subsequent heating, This leads to increased contact resistance and reduced solderability. On the other hand, if an attempt is made to increase the Sn plating thickness of the soldered portion for the purpose of obtaining good solderability, the thickness of the Sn plating at the fitting portion also increases, and the insertion / extraction properties deteriorate.

  Therefore, the above-described prior art solution is considered effective when the thickness of each plating layer applied to the terminal can be sufficiently controlled, but the male terminal has a plating thickness depending on the shape. Distribution may occur, and it may be difficult to apply a uniform plating thickness to the entire terminal. For example, since a male terminal for automobile has a long and narrow bar shape, distribution of current density occurs, resulting in an extreme plating thickness distribution, and the plating thickness increases several times from the center of the terminal to the tip. In order to obtain the predetermined characteristics in the three-layer plating as in the above prior art, it is necessary to strictly control the thickness of each plating layer, but to obtain the desired characteristics due to the plating thickness distribution. Is not easy. Therefore, a plating configuration in which the plating thickness can be easily controlled is desired.

  Therefore, the present invention provides a fitting portion satisfying a low contact resistance and a low insertion / extraction force even in a male terminal having a shape in which a significant distribution of plating thickness occurs and uniform plating over the entire terminal is difficult, and soldering. An object of the present invention is to provide a male terminal having good solderability. Moreover, this invention makes it another subject to provide the manufacturing method of such a male terminal. Moreover, this invention makes it another subject to provide the connector provided with such a male terminal.

As a result of diligent research to solve the above-mentioned problems, the present inventor has adopted a two-layer plating of Ni base + Sn plating without performing Cu plating which is easy to alloy with Sn while the fitting portion is three-layer plating. By adopting the configuration (see FIG. 1), it has been found that the solderability at the soldering portion can be easily achieved with higher certainty at the same time as the low contact resistance and insertion / removability at the fitting portion. That is, the above-described problems can be overcome by partially plating only the fitting portion with Cu plating that is most required to control the plating thickness distribution.
In addition, Sn / Ni two-layer plating forms a Sn—Ni alloy by heating, which adversely affects solderability, but does not require insertion / extraction at the soldered portion, and Sn is relatively thick on the surface layer. It only has to remain. Therefore, strict control of the plating thickness becomes unnecessary. If the soldering part is also made of three-layer plating, the Cu plating layer at the tip becomes thick and excess Cu remains after reflow, so the subsequent growth of the Sn—Cu alloy is faster than the Sn—Ni alloy. In addition, the deterioration of solderability is accelerated rather than Sn / Ni two-layer plating. Also from this point, it can be said that it is preferable that the fitting portion has three layers and the solderability is an Sn / Ni2 layer.

  The present invention completed on the basis of the above knowledge is, in one aspect, a male terminal made of a metal having a fitting portion to be fitted to a female terminal and a soldering portion to be soldered. In the joint part, the Ni plating layer having a thickness of 0.3 to 5.0 μm, the Cu plating layer having a thickness of 0 to 0.3 μm, and the thickness of 0.1 to 0.7 μm are formed on the entire surface of the material or on the two surfaces of the front and back A Cu—Sn alloy layer and a Sn plating layer having a thickness of 0.2 to 1.0 μm are formed in this order, and a Ni plating with a thickness of 0.3 to 5.0 μm is formed on the entire surface of the material from the material side at the soldering portion. The male terminal is characterized in that a layer, a Sn—Ni alloy layer having a thickness of 0.1 to 0.7 μm, and a Sn plating layer having a thickness of 0.3 μm or more are formed in this order.

  In one embodiment of the male terminal according to the present invention, the metal used as the material is copper or a copper alloy.

  In one Embodiment of the male terminal which concerns on this invention, the thickness of the said Cu plating layer in a fitting part is 0-0.2 micrometer.

  In another embodiment of the male terminal according to the present invention, the thickness of the Cu plating layer in the fitting portion is 0 μm.

  In yet another embodiment of the male terminal according to the present invention, the Ni plating layer, an optional Cu plating layer, a Cu-Sn alloy layer, and a Sn plating layer are formed on the entire surface of the material in the fitting portion. ing.

  In still another embodiment of the male terminal according to the present invention, the male terminal has a thickness of 0.4 to 1.0 mm, a fitting portion has a width of 0.5 to 5.0 mm, and a soldering portion. The width is 0.4 to 1.0 mm, and the length from the tip of the fitting portion to the tip of the soldering portion is 15 to 80 mm.

  In yet another embodiment of the male terminal according to the present invention, the male terminal has a solder suction barrier portion between the fitting portion and the soldering portion.

  In still another embodiment of the male terminal according to the present invention, a Ni plating layer, a Ni—Sn alloy layer, or a Cu—Sn alloy layer is formed on the surface of the solder suck-up barrier portion.

  In still another embodiment of the male terminal according to the present invention, the male terminal is for an automobile.

In another aspect, the present invention is a method of manufacturing the male terminal,
(1) a step of pressing a metal flat plate material into a desired male terminal shape;
(2) forming a Ni plating layer having a thickness of 0.3 to 5.0 μm on the entire surface of the material for both the fitting portion and the soldering portion;
(3) forming a Cu plating layer having a thickness of 0.1 to 0.6 μm on the Ni plating layer of the fitting portion without forming a Cu plating layer on the soldering portion;
(4) The fitting portion has a thickness of 0.4 to 1.5 μm on the Cu plating layer, and the soldering portion has a thickness of 1.0 μm or more on the Ni plating layer. Forming a Sn plating layer;
(5) a step of performing a reflow process on the fitting portion and the soldering portion;
It is a manufacturing method containing.

In one embodiment of the manufacturing method of the male terminal according to the present invention,
(1 ′) a step of pressing at least a soldering part on the condition that the fitting part is not pressed from a metal flat plate material;
(2 ′) Ni plating layers having a thickness of 0.3 to 5.0 μm are respectively formed on the front and back surfaces of the material for the fitting portion and on the entire surface of the material for the soldering portion. And a process of
(3 ′) a step of forming a Cu plating layer having a thickness of 0.1 to 0.6 μm on the Ni plating layer of the fitting portion without forming a Cu plating layer on the soldering portion;
(4 ′) A thickness of 0.4 to 1.5 μm is formed on the Cu plating layer of the fitting portion, and a thickness of 1.0 μm or more is formed on the Ni plating layer of the soldering portion. Forming a Sn plating layer comprising:
(5 ′) a step of performing a reflow process on the fitting portion and the soldering portion;
(6 ′) A manufacturing method including a step of forming a desired male terminal shape by pressing a portion that is not pressed including the fitting portion.

  In one embodiment of the manufacturing method according to the present invention, the metal used as the material is copper or a copper alloy.

  In one embodiment of the manufacturing method according to the present invention, the surface Sn plating layer is removed between the fitting portion and the soldering portion, and the Cu—Sn alloy or the Cu—Ni alloy is exposed to the surface to perform soldering. A wicking barrier is formed.

  In yet another aspect, the present invention is a connector incorporating the male terminal.

  The male terminal according to the present invention satisfies the low contact resistance and the low insertion / extraction force at the fitting portion, and has good solderability at the soldering portion. The plating structure employed for the male terminal according to the present invention is relatively simple without requiring precise plating thickness control, particularly precise control of Cu plating thickness as in the case of three-layer plating of the entire terminal. Therefore, it is possible to more reliably obtain desired insertion / removability, energization characteristics, and solderability even for a male terminal having a shape in which plating thickness distribution is likely to occur.

It is the schematic which shows the structure of the plating of this invention. It is the schematic which shows the structure of 3 layer plating. It is the schematic which shows the plating structure in a fitting part. It is the schematic which shows the plating structure in a soldering part. It is the schematic which shows the example of a manufacturing process of the male terminal which concerns on this invention. It is a schematic diagram when the male terminal which concerns on this invention is mounted in the printed circuit board. It is the schematic which shows the example of the shape of a male terminal.

The material of the terminal The metal material used for the male terminal according to the present invention can be any known material used for the terminal without any particular limitation, such as copper, copper alloy, iron, iron alloy (for example, stainless steel), high Nickel alloys can be used. The metal material of the male terminal according to the present invention is preferably copper or a copper alloy in terms of strength, workability, conductivity, and cost. Examples of the copper alloy include brass, phosphor bronze, beryllium copper, white, red, titanium copper, and Corson alloy, which can be appropriately selected according to the required characteristics of the terminal and are not limited at all.

The shape of the terminal is not particularly limited as long as it functions as a male terminal, but the present invention is particularly useful for a terminal having a shape in which a significant distribution occurs in the plating thickness and it is difficult to uniformly plate the entire terminal. . Such a terminal has a narrow terminal width and a long terminal length, and has the following shape, for example.
Terminal length: 15-80mm
Terminal thickness: 0.4 to 1.0 mm
Soldering part: Width 0.4-1.0mm
Mating part: Width 0.5-5.0mm
More typically, such terminals have the following shape.
Terminal length: 20-50mm
Terminal thickness: 0.5-0.8mm
Soldering part: width 0.5-0.8mm
Fitting part: Width 0.64-2.3mm
FIG. 7 shows a specific example of the male terminal shape. The male terminal has a terminal length of 34 mm, a terminal thickness of 0.64 mm, a width of the soldering portion 1 of 0.64 mm, and a width of the fitting portion 2 of 2.3 mm. If desired, a solder suck-up barrier unit 3 may be provided.

Plating Configuration The male terminal according to the present invention has a thickness of 0.3 to 5.0 [mu] m, preferably 0.5 to 4.0 [mu] m, more preferably 0. 6-3.0 μm Ni plating layer, thickness 0-0.3 μm, preferably 0-0.2 μm, more preferably 0 μm Cu plating layer, thickness 0.1-0.7 μm, preferably 0.2-0 .Mu.m, more preferably 0.3-0.5 .mu.m Cu-Sn alloy layer, and thickness 0.2-1.0 .mu.m, preferably 0.2-0.8 .mu.m, more preferably 0.2-0.6 .mu.m. The Sn plating layers are formed in this order.
The male terminal according to the present invention has a thickness of 0.3 to 5.0 μm, preferably 0.5 to 4.0 μm, more preferably 0.6 to 3.0 μm from the material side over the entire surface of the material in the soldering portion. Ni-plated layer, thickness 0.1-0.7 μm, preferably 0.2-0.6 μm, more preferably 0.3-0.5 μm Sn—Ni alloy layer, and thickness 0.3 μm or more, preferably An Sn plating layer of 0.5 μm or more, more preferably 0.5 to 10.0 μm is formed in this order.

  The Ni plating layer formed in both the fitting part and the soldering part suppresses the diffusion of the metal used for the material (typically alloy elements such as Cu, Zn and P) to the surface layer, It helps to maintain good solderability and contact resistance, and it can be electrodeposited uniformly, so that a good appearance can be obtained. When the Ni plating layer is thinner than 0.3 μm, the diffusion preventing effect is small, the solderability and the contact resistance are deteriorated, and the appearance of the finish is impaired. On the other hand, when the Ni plating layer is thicker than 5.0 μm, the diffusion preventing effect is saturated, while the Ni plating layer is cracked in the bending process.

In the Cu—Sn alloy layer formed in the fitting portion, the Cu plating layer is changed by the reflow process. The Cu—Sn alloy layer formed in the fitting portion is a Ni—Sn alloy having poor conductivity due to diffusion of the underlying Ni plating layer to the Sn plating of the surface layer when exposed to changes over time or in a high temperature environment. It is possible to prevent the contact resistance from deteriorating. On the other hand, if the Cu plating layer remains after reflow, Cu and Sn diffusion progresses even after reflow in a high-temperature environment, so an alloy of poor conductivity Cu-Sn is formed on the surface layer and contact resistance deteriorates. The tendency to do is high. Therefore, it is desirable that the Cu plating layer is all changed to a Cu—Sn alloy layer by the reflow treatment, and the thickness is at most about 0.3 μm.
Further, when the thickness of the Cu—Sn alloy layer is less than 0.2 μm, Ni can diffuse into Sn, so that the contact resistance tends to deteriorate. On the other hand, when an excessive reflow process in which the thickness of the Cu—Sn alloy layer exceeds 0.6 μm is performed, the Sn plating on the surface layer is oxidized during the reflow process and the contact resistance is deteriorated.

  The Sn—Ni alloy layer formed in the soldering portion is formed by reflow treatment. However, if the thickness is less than 0.2 μm, the reflow treatment is insufficient and a good appearance cannot be obtained. On the other hand, when the thickness exceeds 1.0 μm, excessive reflow treatment is performed, Sn plating on the surface layer is oxidized, and solderability is deteriorated.

The Sn plating layer formed in the fitting portion has a good contact resistance. However, when the thickness is less than 0.2 μm, a portion in which Sn on the surface layer becomes a Cu—Sn compound due to a diffusion reaction with Cu occurs, and Cu— The tendency that the Sn compound is exposed on the surface and the contact resistance is deteriorated is increased. On the other hand, if the Sn plating layer of the fitting part exceeds 1.0 μm, the insertion / extraction force is increased, which is not preferable.
The Sn plating layer formed on the soldering portion has good solderability. However, when the thickness is less than 0.5 μm, the Ni—Sn compound is exposed on the surface, and the solderability tends to be lowered. On the other hand, there is no particular upper limit to the Sn plating layer of the soldering portion. However, if the Sn plating is thick, powder is generated in the assembly process, so that the thickness is usually about 10 μm, preferably about 5 μm.

The plating configuration according to the present invention can be obtained by applying existing plating techniques, for example:
(1) a step of pressing the material into a desired male terminal shape;
(2) forming a Ni plating layer having a thickness of 0.3 to 5.0 μm on the entire surface of the material for both the fitting part and the soldering part;
(3) forming a Cu plating layer having a thickness of 0.1 to 0.6 μm on the Ni plating layer of the fitting portion without forming a Cu plating layer on the soldering portion;
(4) The fitting portion has a thickness of 0.4 to 1.5 μm on the Cu plating layer, and the soldering portion has a thickness of 1.0 μm or more on the Ni plating layer. Forming a Sn plating layer;
(5) a step of performing a reflow process on the fitting portion and the soldering portion;
It can obtain by the manufacturing method containing.

In the step (2), the Ni plating layer is formed on the entire surface of the material in the fitting part, but the plating thickness at the tip becomes too thick because the width of the fitting part is narrow or long. For the fitting part, if the terminal material is subjected to three-layer plating before pressing (becomes two-sided plating on the front and back sides) and then pressed, the distribution of the plating thickness should be good. it can.
That is, in one embodiment of the manufacturing method of the male terminal according to the present invention,
(1 ′) on the condition that the fitting portion is not pressed from a metal material, and at least a step of pressing the soldering portion;
(2 ′) A step of forming a Ni plating layer having a thickness of 0.3 to 5.0 μm on the front and back surfaces of the material for the fitting portion and on the entire surface of the material for the soldering portion. When,
(3 ′) a step of forming a Cu plating layer having a thickness of 0.1 to 0.6 μm on the Ni plating layer of the fitting portion without forming a Cu plating layer on the soldering portion;
(4 ′) A thickness of 0.4 to 1.5 μm is formed on the Cu plating layer of the fitting portion, and a thickness of 1.0 μm or more is formed on the Ni plating layer of the soldering portion. Forming a Sn plating layer comprising:
(5 ′) a step of performing a reflow process on the fitting portion and the soldering portion;
(6 ′) A manufacturing method including a step of forming a desired male terminal shape by pressing a portion that is not pressed including the fitting portion.
By this procedure, the entire soldered portion is covered with plating, has good solderability, and a good plating thickness distribution can be obtained even in the fitting portion.

  Specific examples of each plating step will be described in detail below.

In the present invention, “Ni plating” includes nickel plating as well as nickel alloy plating such as Ni—P alloy, Ni—Pd alloy, Ni—Co alloy, and Ni—Sn alloy. . Among these, Ni plating is particularly preferable because of high plating speed and low cost. Nickel plating can be performed by any known means, but can be performed by, for example, electric nickel plating.

  Ni plating has a thickness of 0.3 to 5.0 μm, preferably 0.5 to 4.0 μm, more preferably 0.6 to 3.0 μm as a Ni plating layer before reflow treatment in the fitting part and the soldering part. By applying in such a manner, 0.1 to 0.7 μm, preferably 0.2 to 0.6 μm, more preferably 0.3 to 0.5 μm, as the Ni—Sn alloy layer in the soldered portion after the reflow treatment. be able to.

  Depending on the terminal shape, there may be a distribution in the Ni plating thickness of each part, but if it is within the above thickness range, it is acceptable even if the distribution occurs, and the thickness range is relatively wide. The thickness control is not so difficult. Nevertheless, if the thickness distribution is large and the plating thickness cannot satisfy the above range, it can be dealt with by providing a shielding jig or the like on each of the fitting side and the soldering side to equalize the distribution.

Cu plating layer formation process Cu plating is performed in order to form an alloy layer of Cu-Sn by a later reflow process.
In the present invention, “Cu plating” includes Cu plating, for example, Cu—Al alloy, Cu—Bi alloy, Cu—Co alloy, Cu—Ni—P alloy, Cu—Sn—Co alloy, Cu—Fe—. Copper alloy plating such as Ni alloy is also included. The alloy plating may vary in composition, and if the composition of Cu in the alloy plating varies, it is difficult to control the thickness of the Cu—Sn alloy layer generated during the reflow treatment, so Cu plating is particularly preferable. Although Cu plating can be performed by any known means, for example, it can be performed by electric Cu plating.

  The Cu plating is performed on the Ni plating layer on condition that it is not applied to the soldered portion and applied to the fitting portion. Therefore, in one embodiment of the present invention, Cu plating is performed on the entire surface of the terminal, leaving the soldered portion. In another embodiment of the present invention, Cu plating is performed only on the fitting portion. In the present invention, simultaneous control of the thickness of the Cu plating layer in the soldering portion and the fitting portion is unnecessary, and only the adjustment of the thickness of the fitting portion is required, so adjustment of the thickness of the Cu plating layer is facilitated. Is done.

  Cu plating is performed so that the thickness of the Cu plating layer is 0.1 to 0.6 [mu] m, preferably 0.1 to 0.5 [mu] m, more preferably 0.2 to 0.4 [mu] m before reflow treatment at the fitting portion. . When the thickness of the Cu plating layer is less than 0.1 μm, since Ni can diffuse into Sn, the contact resistance tends to deteriorate. On the other hand, when the thickness of the Cu plating layer is larger than 0.6 μm, the Cu layer remains after reflow, and the diffusion of Cu and Sn progresses after reflow. Is formed, and the contact resistance tends to be deteriorated under a high temperature environment. Since the diffusion speed at this time is faster than the diffusion of Ni and Sn, the heat resistance is lower than that of Ni-Sn two-layer plating.

  In general, Cu plating is applied to a part of the terminal by immersing the part of the material to be subjected to Cu plating in a plating solution and using a shielding jig or the like in order to satisfy the above range. Can be achieved.

Sn plating layer formation process In this invention, Sn plating may be given with respect to both a fitting part and a soldering part, and may be given to the whole terminal.
In the present invention, “Sn plating” includes Sn plating as well as Sn alloy plating such as Sn—Cu alloy, Sn—Zn alloy, Sn—Ag alloy, and Sn—Bi alloy. The alloy plating may vary in composition, and if the composition of Sn in the alloy plating varies, it is difficult to control the thickness of the Cu—Sn alloy layer generated during the reflow treatment, and thus Sn plating is particularly preferable. Although Sn plating can be performed by any known means, for example, it can be performed by electric Sn plating.

Sn plating has a thickness of 0.4 to 1.5 [mu] m, preferably 0.5 to 1.1 [mu] m, more preferably 0.6 to 0.8 [mu] m before reflow treatment on the Cu plating layer in the fitting portion. Apply to have. In the fitting portion, when the thickness of the Sn plating layer is thinner than 0.4 μm, the Cu—Sn compound is exposed to the surface after the reflow treatment, and the contact resistance tends to be deteriorated. On the other hand, when it is thicker than 1.5 μm, the Sn plating layer remains thick even after the reflow process, and the insertion / removability deteriorates.
In addition, Sn plating is performed on the Ni plating layer so as to have a thickness of 1.0 μm or more, preferably 1.0 to 10 μm, more preferably 1.0 to 5.0 μm in the soldering portion. When it is thinner than 1.0 μm, the Ni—Sn compound is exposed, and the tendency to lower the solderability is high.

  Since the Sn plating thickness is not required to be as dense as Cu plating, plating may be performed by immersion on the entire surface. However, since a plating thickness distribution is generated, attention must be paid to the method of using the plating tank. In particular, since the plating thickness distribution of the fitting portion should be avoided more than that of the soldering portion, the distribution is made uniform by using a shielding jig or the like. When it is desired to further reduce the thickness distribution at the fitting portion, as described above, the fitting portion is subjected to three-layer plating on the front and back surfaces of the terminal material before pressing, and then the pressing is performed thereafter. The plating thickness can be obtained.

  FIG. 5 shows a schematic diagram of an example of the series of steps as described above.

Reflow treatment The plating surface is smoothed by the reflow process, and the generation of plating powder in the assembly process is suppressed, and the occurrence of whiskers is suppressed. At the time of reflow, a Cu—Sn alloy in the fitting portion and a Ni—Sn alloy layer in the soldering portion are formed.

  The heat applied to the plating material in the reflow process is determined by the line speed and the furnace temperature. When the material is weakly heated, the tin plating does not melt and the above effect cannot be obtained. In addition, when the material is strongly heated, the tin plating surface is discolored by oxidation. Therefore, it is necessary to appropriately determine the line speed and furnace temperature conditions. For example, the reflow treatment is performed at a temperature of 240 to 350 ° C. for 10 to 60 seconds, preferably 250 to 300 ° C. and 20 to 40 seconds. By performing the reflow process under appropriate conditions, a male terminal having a plating configuration according to the present invention can be finally produced.

  FIG. 3 schematically shows the structure of the plating in the fitting portion manufactured by the above process. The structure is such that a Ni plating layer, (Cu plating layer), Cu—Sn alloy layer, and Sn plating layer are formed from the material side. The interface between the Cu—Sn alloy layer and the Sn plating layer is generally cloud-shaped. FIG. 4 shows a schematic diagram of the plating structure in the soldering portion. The structure is such that a Ni plating layer, a Ni—Sn alloy layer, and a Sn plating layer are formed from the material side.

  FIG. 6 exemplarily shows a schematic diagram when the male terminal according to the present invention is mounted on a printed circuit board.

When the solder sucking barrier terminal is downsized, the capillary phenomenon causes the solder to be easily sucked into the terminal at the time of soldering. However, if this sucking occurs excessively, the function and performance of the electronic component may be impaired. For example, in a connector, solder sucks up from the soldering part to the terminal and eventually reaches the contact part with the mating connector, so that the connection reliability of the connector is impaired, or solder that reaches the nearby soldering part and short-circuits. There may be a problem that a bridge is generated or a sufficient amount of solder does not remain in the soldering portion. Therefore, a solder suction barrier portion with poor solder wettability may be formed between the fitting portion and the soldering portion. The Ni plating layer, Ni—Sn alloy layer, or Cu—Sn alloy layer formed on the surface layer is effective as a solder suck-up barrier portion.
The solder suck-up barrier portion can be formed by any known method. For example, the Ni plating layer, the optional Cu plating layer, and the Sn plating layer are previously formed on the portion that becomes the solder suck-up barrier portion. After forming and reflowing, the surface Sn can be removed by laser irradiation, electrolytic polishing, chemical polishing, or the like to expose the Ni—Sn alloy layer or the Cu—Sn alloy layer.
In particular, in the case of a male terminal for an automobile, a step of bending the terminal at a right angle at an intermediate point between the fitting portion and the soldering portion is added in the connector assembly process. This is beneficial because it sometimes leads to the effect of preventing the Sn plating from being scraped off by the bent metal fitting and adhering to the connector as a foreign substance.

In the present invention, the thickness of each plating layer and alloy layer is determined as follows.
In addition, the measurement location of each plating layer and alloy layer thickness was measured in the center part of the width direction of 1 +/- 0.2mm from the terminal tip in both the fitting part and the soldering part.
Since only Sn layer can be removed by Sn plating layer electrolysis, Sn plating thickness is measured by fluorescent X-ray before and after electrolysis, and Sn plating thickness is obtained by subtracting plating thickness after electrolysis from Sn plating thickness before electrolysis Layer thickness.
The thickness of the Cu—Sn alloy layer Cu—Sn is the value measured as the Sn plating thickness with fluorescent X-rays after removing only the Sn plating layer by electrolysis.
The thickness of the alloy layer of the Ni—Sn alloy layer Ni—Sn is a numerical value measured as the Sn plating thickness with fluorescent X-rays after removing only the Sn plating layer by electrolysis.
Cu plating layer and Ni plating layer The thicknesses of the Cu layer and the Ni layer are obtained by SEM observation of the plating cross section at 5000 to 20000 times, and take the average value at 10 locations.

  The male terminal according to the present invention can be mounted on a connector, and is particularly suitable for an automobile or the like that is planned to be used in a high temperature environment.

  In order to better understand the present invention and the advantages thereof, examples of the male terminal and the manufacturing method thereof according to the present invention will be described below, but these are for illustrative purposes and the present invention is intended to be limited. Not what you want.

  For the measurement of the thickness of each plating layer and alloy layer, a micro fluorescent X-ray film thickness meter (manufactured by SII: model SFT-9255) and SEM (manufactured by JEOL: model JSM-7000F) were used according to the measurement conditions described above. The plating thickness was measured.

  For evaluation of insertion / extraction, a commercially available Cu base reflow Sn-plated female terminal (Sn plating thickness: 1.1 μm) was used, and the fitting force at the time of insertion was measured by an insertion / extraction tester.

  The contact resistance was measured by a 4-terminal method using a Yamazaki contact simulator.

For the evaluation of solderability, according to JIS C 0053, the solder wetting time was measured by the meniscograph method under the following conditions.
Solder: Lead-free solder Sn-3.0Ag-0.5Cu (M705 manufactured by Senju Metal Co., Ltd.)
Solder bath temperature: 250 ° C
Flux: 25% rosin ethanol Measuring instrument: Solder Checker (SA-5000 manufactured by Reska)
Immersion speed: 20 mm / s
Immersion depth: 2mm
Immersion time: 10s

  Moreover, the solderability after heating each terminal for 16 hours at 155 ° C. and the contact resistance after heating for 184 hours at 155 ° C. were evaluated, and heat resistance was observed.

No. 1 (Example)
A male terminal was manufactured using a brass pressed material having a fitting portion width of 2.3 mm, a soldering portion width of 0.64 mm, and a thickness of 0.64 mm having the shape shown in FIG. The press material was processed in the order of pretreatment, Ni plating, Cu plating, Sn plating, and reflow, and the characteristics were investigated.

The pretreatment was performed under the following conditions.
Using an alkaline degreasing solution containing NaOH, electrolytic degreasing was carried out under conditions of 60 ° C. and a current density of 7 A / dm ² , followed by pickling with 10% dilute sulfuric acid.

Ni plating was performed under the following conditions.
Ni plating was carried out using a sulfamic acid bath at 55 ° C. and a current density of 0.6 to 30 A / dm ² .

Cu plating was performed under the following conditions.
Cu plating was performed using a copper sulfate bath at 40 ° C. and a current density of ^{2 to} 15 A / dm ² .

Sn plating was performed under the following conditions.
Sn plating was performed using a methanesulfonic acid bath at 55 ° C. and a current density of 5 to 40 A / dm ² .

The reflow process was performed under the following conditions.
The furnace temperature was set to 450 ° C., the reflow treatment was performed with a residence time of 25 seconds, and then water cooling was performed.

No. 2 (Example) -No. 15 (Comparative example)
In Examples 2 to 7 and Comparative Examples 9 to 15, the current value was changed to change the Ni plating thickness, Cu plating thickness, and Sn plating thickness, and the reflow temperature was adjusted to ± 50 ° C. in order to adjust the appearance of Sn. A male terminal was manufactured under the same conditions as in Example 1 except that the range was changed. No. No. 8 (Example) is a product obtained by punching only the soldering portion with a primary press and plating the fitting portion with a flat plate, and punching the fitting portion with a secondary press after plating. No. The reason why the fitting portion 8 is plated as it is before pressing is that the plating thickness distribution of the fitting portion can be managed in a narrower range.

The results are shown in Table 1.
No. 1 to 8 (Examples) were within the specified range of the present invention and exhibited good characteristics.
No. In No. 2, Cu remained 0.2 μm even after reflow, and Sn on the surface layer was as thin as 0.2 μm, so the contact resistance slightly increased after heating. However, it is a usable level as a connector.
No. No. 5 has 0.3 μm of Cu remaining after reflow, but since the Sn of the surface layer is as thick as 1.0 μm, there is no deterioration in contact resistance due to heating. Moreover, although the fitting force is a slightly high value, it is a usable level.
No. Since No. 8 can be managed in a narrow range of plating thickness distribution, the Sn thickness after reflow can be as thin as 0.3 μm and the fitting force is small. Also, since there is no remaining Cu plating, No. Similar to 1 to 7 (excluding No. 2), there is no deterioration of contact resistance due to heating.
No. 9 and 10 (comparative examples) are examples in which the contact resistance of the fitting portion deteriorated after heating because there was no Cu plating in the fitting portion or the Cu plating thickness was thin.
No. 11 (Comparative Example) is an example in which the contact resistance of the fitting portion deteriorated after heating because the Cu plating thickness of the fitting portion was thick.
No. 12 (Comparative Example) is an example in which the entire terminal including not only the fitting portion but also the soldering portion is plated with Cu, but unlike the example of partial plating with only the fitting portion, it is difficult to control the Cu plating thickness profile. Therefore, as a result of plating more than necessary Cu, Cu remains even after reflow, and the solderability of the soldered portion after heating is reduced.
No. 13 (comparative example) is an example in which the contact resistance of the fitting portion deteriorated after heating because the Sn plating thickness of the fitting portion was thin.
No. No. 14 (comparative example) is an example in which the soldering property of the soldering part deteriorates after heating because the Sn plating thickness of the soldering part is thin.
No. 15 (Comparative Example) is an example in which the insertion / extraction force is increased because the Sn plating thickness of the fitting portion is thick.

Claims (14)

  It is a male terminal made of a metal having a fitting portion to be fitted to a female terminal and a soldering portion to be soldered, and the fitting portion is formed on the entire surface of the material or on the front and back surfaces from the material side. Ni plating layer having a thickness of 0.3 to 5.0 μm, Cu plating layer having a thickness of 0 to 0.3 μm, Cu—Sn alloy layer having a thickness of 0.1 to 0.7 μm, and Sn having a thickness of 0.2 to 1.0 μm A plating layer is formed in this order, and a soldering portion has a Ni plating layer having a thickness of 0.3 to 5.0 μm, a Sn—Ni alloy layer having a thickness of 0.1 to 0.7 μm from the material side over the entire surface of the material, And a Sn plating layer having a thickness of 0.3 μm or more is formed in this order.   The male terminal according to claim 1, wherein the metal used as a material is copper or a copper alloy.   The male terminal according to claim 1 or 2, wherein a thickness of the Cu plating layer in the fitting portion is 0 to 0.2 µm.   The male terminal according to claim 3, wherein the thickness of the Cu plating layer in the fitting portion is 0 μm.   The fitting part is formed with the Ni plating layer, optional Cu plating layer, Cu-Sn alloy layer, and Sn plating layer only on the front and back surfaces of the material. The male terminal described.   The male terminal has a thickness of 0.4 to 1.0 mm, a fitting portion having a width of 0.5 to 5.0 mm, a soldering portion having a width of 0.4 to 1.0 mm, and soldering from the tip of the fitting portion. The male terminal as described in any one of Claims 1-5 which has a shape whose length is 15-80 mm to the front-end | tip of a part. The male terminal according to any one of claims 1 to 6 , further comprising a solder suction barrier portion between the fitting portion and the soldering portion.   The male terminal according to claim 7, wherein a Ni plating layer, a Ni—Sn alloy layer, or a Cu—Sn alloy layer is formed on a surface layer of the solder sucking-up barrier portion.   The male terminal as described in any one of Claims 1-8 used for a motor vehicle. (1) a step of pressing a metal flat plate material into a desired male terminal shape;
(2) forming a Ni plating layer having a thickness of 0.3 to 5.0 μm on the entire surface of the material for both the fitting portion and the soldering portion;
(3) forming a Cu plating layer having a thickness of 0.1 to 0.6 μm on the Ni plating layer of the fitting portion without forming a Cu plating layer on the soldering portion;
(4) The fitting portion has a thickness of 0.4 to 1.5 μm on the Cu plating layer, and the soldering portion has a thickness of 1.0 μm or more on the Ni plating layer. Forming a Sn plating layer;
(5) a step of performing a reflow process on the fitting portion and the soldering portion;
The manufacturing method of the male terminal as described in any one of Claims 1-9 containing. (1 ′) a step of pressing at least a soldering part on the condition that the fitting part is not pressed from a metal flat plate material;
(2 ′) Ni plating layers having a thickness of 0.3 to 5.0 μm are respectively formed on the front and back surfaces of the material for the fitting portion and on the entire surface of the material for the soldering portion. And a process of
(3 ′) a step of forming a Cu plating layer having a thickness of 0.1 to 0.6 μm on the Ni plating layer of the fitting portion without forming a Cu plating layer on the soldering portion;
(4 ′) A thickness of 0.4 to 1.5 μm is formed on the Cu plating layer of the fitting portion, and a thickness of 1.0 μm or more is formed on the Ni plating layer of the soldering portion. Forming a Sn plating layer comprising:
(5 ′) a step of performing a reflow process on the fitting portion and the soldering portion;
(6 ′) a step of forming a desired male terminal shape by pressing a portion that is not pressed including the fitting portion;
The manufacturing method of the male terminal as described in any one of Claims 1-9 containing. The manufacturing method according to claim 10 or 11 , wherein the metal used as a material is copper or a copper alloy. The surface layer of the Sn-plated layer was removed during the fitting portion and the soldering portion, according to claim 10-14 comprising the step of forming a solder sucking up barrier section by a method of exposing the Cu-Sn alloy or Cu-Ni alloy on the surface 12. The production method according to any one of 12 above.   The connector which incorporated the male terminal as described in any one of Claims 1-9.

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