JP2022082619A - PCB terminal manufacturing method and PCB terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PCB terminal which has excellent wear resistance, conductivity, sliding property and low friction property and can reduce the use amount of expensive gold, and to provide a manufacturing method of the same.

SOLUTION: A comb-shaped PCB terminal has a plurality of substantially quadrilateral male terminals, a nickel plating layer having a thickness of 0.3 μm to 4.0 μm is formed on an entire surface of the male terminals, a thin gold-plated layer having a thickness of more than 0 and 0.1 μm or less is formed on an entire surface of the nickel plating layer, and a thick gold-plated layer having a thickness of 0.2 μm to 1.0 μm is formed only on a surface of the nickel plating layer formed on the front and back surfaces of the male terminals.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a method for manufacturing a PCB terminal and a PCB terminal, and more specifically, to manufacture a PCB terminal having excellent wear resistance, conductivity, slidability and low friction, and excellent in economy. The method and the PCB terminal.

PCB terminals are used in various connectors for automobiles and consumer use, and are indispensable for mounting printed circuit boards. Generally, by punching out a flat sheet-shaped metal substrate, a plurality of terminals are arranged in a comb-teeth shape.

Further, in order to realize good electric contacts, the PCB terminal is required to have excellent electrical conductivity and wear resistance, and the tip of the male terminal that fits with the female terminal may be surface-treated. many. For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2008-287942) proposes a terminal for a PCB connector having a Sn plating on the outermost surface.

In the PCB connector terminal described in Patent Document 1, the friction coefficient of the fitting portion can be 0.26 or less, and the zero cross time after aging of the soldered portion can be 5 seconds or less, so that the terminal can be inserted into the connector. It is said that it is possible to provide a PCB terminal and a method for manufacturing the same, which are excellent in reducing the insertion force and improving the solder wettability of the soldered portion to the substrate side.

Further, in Patent Document 2 (Japanese Unexamined Patent Publication No. 2005-206893), the surface of a terminal for a connector made of copper or a copper alloy has an energy density in which the surface layer portion is in a predetermined melting state by irradiation, and the melting is described. A terminal for a connector characterized in that a copper amorphous layer is formed on the surface portion by irradiating at least once a pulse of an electron beam having a short irradiation time limited to an energy irradiation amount in which the surface layer portion is immediately re-solidified after dissolution. A surface modification method has been proposed.

In the method for surface modification of connector terminals described in Patent Document 2, since a copper amorphous layer is formed by irradiation with an electron beam, the surface roughness is remarkably improved, the wear resistance is increased, and the oxidation resistance is increased. It is said that it is possible to obtain a terminal for a connector having excellent characteristics such as corrosion resistance and sustaining without deterioration of electrical characteristics such as electrical contact resistance.

In addition, in the method for surface modification of the connector terminal described in Patent Document 2, since a copper amorphous layer having the above characteristics can be formed, it is necessary to perform gold plating treatment for ensuring corrosion resistance and electrical characteristics. It is said that it is possible to avoid the use of expensive gold.

Japanese Unexamined Patent Publication No. 2008-287942 Japanese Unexamined Patent Publication No. 2005-206893

However, although the PCB terminal described in Patent Document 1 has improved sliding characteristics and solder wettability, the outermost surface is a tin-plated layer, and the electrical conductivity and durability are improved as compared with the gold-plated layer. Not enough.

Further, since the electron beam is used in the surface modification method of the connector terminal described in Patent Document 2, processing in a vacuum is indispensable, which not only complicates the manufacturing process but also increases the cost. .. Further, it is necessary to irradiate the electron beam for each region where the copper amorphous layer is required, which requires a long time as compared with the plating treatment or the like.

In view of the above problems in the prior art, an object of the present invention is to have excellent wear resistance, conductivity, slidability and low friction, and to reduce the amount of expensive gold used. It is an object of the present invention to provide a PCB terminal capable of being used and a method for manufacturing the same.

As a result of diligent research on the surface treatment method of the PCB terminal in order to achieve the above object, the present inventor has found that it is extremely effective to apply an appropriate gold plating treatment only to the required region of the male terminal. , The present invention has been reached.

That is, the present invention
It is a method for manufacturing a comb-shaped PCB terminal having a plurality of male terminals having a substantially square pillar shape.
The first step of subjecting the metal base material in the shape of the PCB terminal to nickel plating and forming a nickel plating layer on the entire surface of the male terminal.
The second step of applying masking treatment to the front surface and the back surface of the male terminal to form a masking layer, and
A third step of applying a resist to the entire surface of the male terminal, peeling off the masking layer, and curing the resist to form resist layers on both side surfaces of the male terminal.
A fourth step of subjecting the male terminal to gold plating, forming a gold plating layer on the front surface and the back surface of the male terminal, and then peeling off the resist layer.
Provided is a method for manufacturing a PCB terminal.

In the method for manufacturing a PCB terminal of the present invention, a gold plating layer can be formed only on the front surface and the back surface of a male terminal that contributes to energization when fitted with a female terminal, and on both sides that do not come into contact with the female terminal. It is possible to prevent the formation of the gold-plated layer. As a result, the amount of gold consumed for forming the gold plating layer can be efficiently reduced.

It is difficult to form a good gold-plated layer in an arbitrary region on a comb-shaped metal substrate having a complicated shape, but in the method for manufacturing a PCB terminal of the present invention, a gold-plated layer is formed. By forming the masking layer on the front surface and the back surface of the male terminal, the formation of the resist layer can be suppressed, and the gold plating layer can be formed only on the front surface and the back surface of the male terminal in the fourth step.

In the method for manufacturing a PCB terminal of the present invention, it is preferable to have a step of applying a gold flash plating treatment to the surface of the nickel plating layer. By forming the gold flash plating layer on the surface of the nickel plating layer, the adhesion between the gold plating layer formed in the fourth step and the nickel plating layer can be sufficiently ensured.

Further, in the method for manufacturing a PCB terminal of the present invention, it is preferable to have a step of applying a base strike plating treatment to the metal substrate as a preliminary treatment of the first step. By applying the base strike plating treatment to the metal base material, the adhesion between the nickel plating layer and the metal base material can be sufficiently ensured. As the base strike plating treatment, for example, a copper strike plating treatment, a nickel strike plating treatment, or the like can be used.

Further, in the method for manufacturing a PCB terminal of the present invention, it is preferable to air-cool the resist immediately after curing. The resist layer may have heat due to curing, but by air cooling immediately after the resist, the influence on the next process can be eliminated.

Further, in the method for manufacturing a PCB terminal of the present invention, it is preferable that the thickness of the gold plating layer is 0.2 μm to 1.0 μm. By setting the thickness of the gold plating layer to 0.2 μm or more, the electrical characteristics and durability of gold can be fully utilized, and by setting it to 1.0 μm or less, the amount of gold used can be suppressed. In addition, deterioration of productivity can be suppressed. The thickness of the gold plating layer is more preferably 0.4 μm to 0.8 μm, and most preferably 0.5 μm to 0.7 μm.

Further, in the method for manufacturing a PCB terminal of the present invention, it is preferable that the thickness of the gold flash plating layer formed on the surface of the nickel plating layer is more than 0 and 0.1 μm or less. By setting the thickness of the gold flash plating layer to 0.1 μm or less, it is possible to suppress an increase in the amount of gold used and a deterioration in productivity. The thickness of the gold flash plating layer is more preferably 0.08 μm or less, and most preferably 0.06 μm or less.

Further, in the method for manufacturing a PCB terminal of the present invention, it is preferable that the thickness of the nickel plating layer is 0.3 μm to 4.0 μm. By setting the thickness of the nickel-plated layer to 0.3 μm or more, it is possible to suppress the brittleness of the gold-plated layer due to the diffusion of the element contained in the metal substrate and gold and the formation of an intermetal compound due to the reaction. By setting the thickness to 4.0 μm or less, it is possible to suppress deterioration of conductivity, mechanical properties, etc. due to the presence of the nickel-plated layer. The thickness of the nickel plating layer is more preferably 0.4 μm to 2.0 μm, and most preferably 0.5 μm to 1.5 μm.

Further, in the method for manufacturing a PCB terminal of the present invention, it is preferable to use a negative resist as the resist. If a positive resist is used, the third to fourth steps need to be performed in a dark room, which complicates the apparatus and increases the manufacturing cost. On the other hand, by selecting the negative type, these problems can be eliminated.

Further, the present invention
It is a comb-shaped PCB terminal that has a plurality of male terminals in the shape of a substantially square pillar.
The male terminal has a nickel plating layer on the entire surface and has a nickel plating layer.
A thick gold plating layer having a thickness of 0.2 μm to 1.0 μm is formed only on the front surface and the back surface of the nickel plating layer formed on the front surface and the back surface of the male terminal.
Also provided is a PCB terminal, characterized by.

In the PCB terminal of the present invention, since the thick gold-plated layer is formed on the front surface and the back surface of the male terminal that mainly contacts the female terminal at the time of fitting, sufficient energization characteristics can be ensured. On the other hand, thick gold plating layers are not formed on both side surfaces of the male terminal, which hardly contributes to the energization characteristics, and the amount of gold used is kept to a minimum.

In the present specification, the thick gold-plated layer means a gold-plated layer having a thickness of 0.2 μm to 1.0 μm. By setting the thickness of the gold plating layer to 0.2 μm or more, the electrical characteristics and durability of gold can be fully utilized, and by setting it to 1.0 μm or less, the amount of gold used can be suppressed. In addition, deterioration of productivity can be suppressed. The thickness of the thickened gold plating layer is more preferably 0.4 μm to 0.8 μm, and most preferably 0.5 μm to 0.7 μm.

Further, in the PCB terminal of the present invention, nickel plating is formed on the entire surface of the terminal, which prevents the gold plating layer from becoming brittle due to the diffusion of the element contained in the metal substrate and gold and the formation of an intermetallic compound due to the reaction. It can be suppressed.

Further, in the PCB terminal of the present invention, it is preferable that a thin gold plating layer having a thickness of more than 0 and 0.1 μm or less is formed on the entire surface of the nickel plating layer. In the present specification, the thin gold-plated layer means a gold-plated layer having a thickness of 0.1 μm or less formed by the gold flash plating process. The thickness of the thin gold plating layer is more preferably 0.08 μm or less, and most preferably 0.06 μm or less.

According to the PCB terminal of the present invention and the method for manufacturing the same, the PCB terminal having excellent wear resistance, electrical conductivity, slidability and low friction, and capable of reducing the amount of expensive gold used, and the PCB terminal. The manufacturing method can be provided.

It is a process drawing of the manufacturing method of the PCB terminal of this invention. It is a schematic perspective view which shows an example of the PCB terminal of this invention. FIG. 3 is a cross-sectional view taken along the line AA'of the male terminal 4. It is an overview photograph of the PCB terminal obtained in the Example.

Hereinafter, typical embodiments of the PCB terminal of the present invention and the method for manufacturing the same will be described in detail with reference to the drawings, but the present invention is not limited to these. In the following description, the same or corresponding parts may be designated by the same reference numerals, and duplicate description may be omitted. Further, since the drawings are for conceptually explaining the present invention, the dimensions of each component represented and their ratios may differ from the actual ones.

≪Manufacturing method of PCB terminal≫
FIG. 1 is a process diagram of the method for manufacturing a PCB terminal of the present invention. The method for manufacturing a PCB terminal of the present invention is an efficient method for manufacturing a PCB terminal having a gold-plated layer only on the front surface and the back surface of the male terminal. The first step (S01) of forming a nickel plating layer on the entire surface of the male terminal, the second step (S02) of forming a masking layer on the front surface and the back surface of the male terminal, and forming a resist layer on both side surfaces of the male terminal. It is characterized by including a third step (S03) and a fourth step (S04) of forming a gold-plated layer on the front surface and the back surface of the male terminal. Hereinafter, each step will be described in detail.

(1) Preliminary treatment PCB terminals are manufactured using an appropriate metal base material as a starting material. The metal base material is processed into the shape of a PCB terminal, and has a comb-teeth shape having a plurality of male terminals having a substantially quadrangular prism shape. Here, the shape, size, number, and the like of the terminals are not particularly limited, and may be determined according to the requirements as the PCB terminals.

The metal used for the metal base material is not particularly limited as long as it has electrical conductivity, and is, for example, aluminum and aluminum alloys, iron and iron alloys (for example, iron-nickel alloys), titanium and titanium alloys, stainless steel, copper and the like. Although copper alloys and the like can be mentioned, it is preferable to use copper or brass because of its excellent electrical conductivity, thermal conductivity, and spreadability.

Further, it is preferable to wash the metal base material as a preliminary treatment for various plating treatments. The method for cleaning the metal substrate is not particularly limited as long as the effect of the present invention is not impaired, and various conventionally known cleaning methods can be used. As the cleaning treatment liquid, for example, a general immersion degreasing liquid or electrolytic degreasing liquid can be used.

(2) Base strike plating treatment The base strike plating treatment is a preliminary treatment of the first step (S01), and is preferably performed when it is necessary to improve the adhesion between the metal base material and the nickel plating layer. As the base strike plating treatment, for example, a copper strike plating treatment, a nickel strike plating treatment, or the like can be used.

(A) Copper Strike Plating As the copper strike plating bath, for example, one containing a copper salt and a conductive salt can be used. Further, a brightener may be added.

As the copper strike plating bath that can be suitably used for the copper strike plating treatment, for example, a copper cyanide bath can be used. The copper cyanide bath is composed of a copper salt, an alkali cyanide salt and a conductive salt, and an additive or a brightener may be added.

As the copper salt, for example, copper cyanide can be used. As the cyanide alkali salt, for example, potassium cyanide, sodium cyanide and the like can be used. As the conductive salt, for example, potassium carbonate, sodium carbonate and the like can be used. As the additive, for example, Rochelle salt, potassium selenate, sodium selenite, potassium thiocyanate, lead acetate, lead tartrate and the like can be used.

The copper strike plating conditions such as the bath temperature of the copper strike plating bath, the anode material, and the current density can be appropriately set according to the plating bath to be used, the required plating thickness, and the like. For example, as the anode material, it is preferable to use a soluble anode such as electrolytic copper and / or an insoluble anode such as stainless steel, titanium platinum plate, and iridium oxide. Further, as suitable plating conditions, a bath temperature of 25 to 70 ° C., a current density of 0.1 to 6.0 A / dm ² , and a processing time of 5 to 60 seconds can be exemplified.

(B) Nickel Strike Plating As the nickel strike plating bath, for example, one containing a nickel salt, an anodizing accelerator and a pH buffering agent can be used. Further, an additive may be added to the nickel strike plating bath.

As the nickel salt, for example, nickel sulfate, nickel sulfamate, nickel chloride and the like can be used. As the anodic dissolution accelerator, for example, nickel chloride, hydrochloric acid or the like can be used. As the pH buffer, for example, boric acid, nickel acetate, citric acid and the like can be used. Additives include, for example, primary brighteners (saccharin, benzene, naphthalene (di, tri), sodium sulfonic acid, sulfonamide, sulfinic acid, etc.) and secondary brighteners (organic compounds: butinediol, coumarin, allylaldehyde). Metal salts such as sulfonic acid: cobalt, lead, zinc, etc.) and pit inhibitors (sodium lauryl sulfate, etc.) can be used.

Suitable amounts of each component of the nickel strike plating bath that can be suitably used for the nickel strike plating treatment are nickel salt: 100 to 300 g / L, anodic dissolution accelerator: 0 to 300 g / L, pH buffer: 0 to 50 g / L, additive: 0 to 20 g / L.

The nickel strike plating conditions such as the bath temperature of the nickel strike plating bath, the anode material, and the current density can be appropriately set according to the plating bath to be used, the required plating thickness, and the like. For example, as the anode material, it is preferable to use a soluble anode such as electrolytic nickel, carbonized nickel, depolized nickel, and sulfa nickel. Further, as suitable plating conditions, bath temperature: 20 to 30 ° C., current density: 1.0 to 5.0 A / dm ² , treatment time: 1 to 30 seconds, pH: 0.5 to 4.5 are exemplified. can do.

(3) Nickel plating treatment (first step (S01))
The nickel plating treatment is performed to form a nickel plating layer between the metal base material and the gold plating layer, which functions as a barrier layer for preventing diffusion and reaction between the elements contained in the metal base material and gold. It is a process. The presence of the nickel plating layer between the metal base material and the gold plating layer suppresses the brittleness of the gold plating layer due to the diffusion of the elements contained in the metal base material and gold and the formation of intermetallic compounds due to the reaction. can do.

As the nickel plating bath, for example, a watt bath or a sulfamic acid bath can be used, but it is preferable to use a sulfamic acid bath having a low electrodeposition stress. It is preferable to avoid a strongly acidic wood strike bath. For the nickel plating treatment, various conventionally known nickel plating methods can be used as long as the effects of the present invention are not impaired. For example, a nickel plating bath is made up of a liquid composed of nickel salts such as nickel sulfate, nickel sulfamate, nickel chloride, an anode dissolving agent such as nickel chloride, and a pH buffering agent such as boric acid, acetic acid, and citric acid. As an additive, a brightener, a leveling agent, a pit inhibitor, or the like added with a small amount can be used. Suitable amounts of each component used are nickel salt: 100-600 g / L, anolytic agent: 0-50 g / L, pH buffer: 20-50 g / L, additive: -5000 ppm.

Nickel plating conditions such as the bath temperature of the nickel plating bath, the anode material, and the current density can be appropriately set according to the plating bath to be used, the required plating thickness, and the like. For example, it is preferable to use a soluble anode such as a nickel plate as the anode material. Further, as suitable plating conditions, bath temperature: 40 to 60 ° C., current density: 0.1 to 50 A / dm ² , pH: 3.0 to 5.0 can be exemplified.

The nickel plating layer formed by the nickel plating treatment in the first step preferably has a continuous film shape, and the thickness of the nickel plating layer is preferably 0.3 μm to 4.0 μm. If it is less than 0.3 μm, the barrier effect is poor, and if it is more than 4 μm, cracks are likely to occur during bending. The thickness of the nickel plating layer is more preferably 0.4 μm to 2.0 μm, and most preferably 0.5 μm to 1.5 μm. The nickel-plated layer may have a granular or island-shaped discontinuous film shape as long as the effect of the present invention is not impaired, and in that case, the granular and island-shaped portions may be partially continuous. good.

(4) Gold plating flash treatment The gold plating flash treatment is a treatment for the nickel plating layer formed in the first step (S01), and in the method for manufacturing a PCB terminal of the present invention, the surface of the nickel plating layer is gold-plated. It is preferable to have a step of performing flash treatment. By applying the gold plating flash treatment, it is possible to impart corrosion resistance to a portion that is not a fitting portion (a portion that does not require a thick gold plating layer). Further, by forming a thin gold plating layer on the surface of the nickel plating layer, the adhesion between the gold plating layer formed in the fourth step (S04) and the nickel plating layer can be sufficiently ensured. The gold plating flash treatment may be performed after the gold plating treatment.

As the gold plating flash bath, for example, one containing a gold salt, a conductive salt, a chelating agent and a crystal growth agent can be used. Further, a brightener may be added to the gold-plated flash bath.

As the gold salt, for example, gold cyanide, potassium primary gold cyanide, potassium secondary gold cyanide, sodium gold sulfite, sodium gold thiosulfate and the like can be used. As the conducting salt, for example, potassium citrate, potassium phosphate, potassium pyrophosphate, potassium thiosulfate and the like can be used. As the chelating agent, for example, ethylenediaminetetraacetic acid, methylenephosphonic acid and the like can be used. As the crystal growth agent, for example, cobalt, nickel, thallium, silver, palladium, tin, zinc, copper, bismuth, indium, arsenic, cadmium and the like can be used. As the pH adjuster, for example, polyphosphoric acid, citric acid, tartaric acid, potassium hydroxide, hydrochloric acid and the like may be added.

Suitable amounts of each component of the gold-plated flash bath that can be suitably used for the gold-plated flash treatment are gold salt: 1 to 10 g / L, conductive salt: 0 to 200 g / L, chelating agent: 0 to 30 g. / L, crystal growth agent: 0 to 30 g / L.

The gold plating flash conditions such as the bath temperature, the anode material, and the current density of the gold plating flash bath can be appropriately set according to the plating bath to be used, the required plating thickness, and the like. For example, it is preferable to use a titanium platinum plate, an insoluble anode such as iridium oxide, or the like as the anode material. Further, as suitable plating conditions, bath temperature: 20 to 40 ° C., current density: 0.1 to 5.0 A / dm ² , treatment time: 1 to 60 seconds, pH: 0.5 to 7.0 are exemplified. can do.

(5) Masking process (second step (S02))
The masking process is a process for forming a masking layer that prevents the formation of the resist layer in the third step (S03). Before the masking treatment, it is preferable to dry the metal substrate subjected to various plating treatments with a dryer or the like. Here, in order to prevent the resist layer from being formed on the front surface and the back surface of the male terminal in the third step (S03), it is necessary to perform masking treatment on the front surface and the back surface of the male terminal.

The masking method is not particularly limited as long as the effect of the present invention is not impaired, and various conventionally known masking methods can be used. Examples of the masking method include a tape, a sparger mask, a drum mask, a resist, a dry film resist, and an inkjet method, and it is preferable to perform masking by using one or a combination of two or more of these.

In particular, when it is desired to form a resist layer only on the side surface of the base material, it is possible to mask the surface with a tape or a drum mask in the first step and form a resist layer only on the side surface using a liquid resist in the second step. preferable.

(6) Formation of resist layer (third step (S03))
In the third step (S03), the masking formed in the second step is peeled off after the resist is applied, and the resist is applied to the region (both sides of the male terminal) where the gold plating layer is not desired to be formed in the fourth step (S04). It is a process for forming.

After removing the masking, the resist can be cured by exposing it to UV light (mercury lamp, metal halide lamp, LED, etc.).

The resist includes a negative type, a positive type, an electrodeposition resist, a liquid resist, a dry film resist and the like, but it is preferable to use a negative type that does not require a dark room in the plating tank.

(7) Gold plating (fourth step (S04))
The fourth step (S04) is a step for forming a gold plating layer only on the front surface and the back surface of the male terminal. By going through the third step (S03), resist layers are formed on both side surfaces of the male terminal, and the front surface and the back surface of the male terminal become a nickel plating layer or a thin gold plating layer formed by gold plating flash treatment. Therefore, by performing the gold plating treatment in the fourth step (S04), the gold plating layer can be formed only on the front surface and the back surface of the male terminal.

The thickness of the gold plating layer is preferably 0.2 μm to 1.0 μm. By setting the thickness of the gold plating layer to 0.2 μm or more, the electrical characteristics and durability of gold can be fully utilized, and by setting it to 1.0 μm or less, the amount of gold used can be suppressed. In addition, deterioration of productivity can be suppressed. The thickness of the gold plating layer is more preferably 0.4 μm to 0.8 μm, and most preferably 0.5 μm to 0.7 μm.

Various conventionally known gold plating methods can be used for the gold plating treatment as long as the effects of the present invention are not impaired, but the concentration of gold salt in the plating bath is higher than that of ordinary gold flash plating. , It is preferable to reduce the concentration of the conductive salt.

As the gold plating bath that can be suitably used for the gold plating treatment, for example, one containing a gold salt, a conductive salt, a chelating agent and a crystal growth agent can be used. Further, a brightener may be added to the gold plating bath. Suitable amounts of each component are gold salt: 1 to 100 g / L, conductive salt: 10 to 300 g / L, chelating agent: ~ 30 g / L, crystal growth material: ~ 30 g / L, brightener: 50 ~. It is 500 ppm.

Examples of the gold salt include gold cyanide, potassium primary gold cyanide, potassium secondary gold cyanide, sodium gold sulfite, sodium gold thiosulfate and the like, and examples of the conductive salt include potassium citrate and phosphorus. Examples thereof include potassium acid, potassium pyrophosphate, potassium thiosulfate and the like.

As the chelating agent, for example, ethylenediaminetetraacetic acid, methylenephosphonic acid and the like can be used. As the crystal growth agent, for example, cobalt, nickel, thallium, silver, palladium, tin, zinc, copper, bismuth, indium, arsenic, cadmium and the like can be used. As the pH adjuster, for example, polyphosphoric acid, citric acid, tartaric acid, potassium hydroxide, hydrochloric acid and the like may be added.

The gold plating conditions such as the bath temperature of the gold plating bath, the anode material, and the current density can be appropriately set according to the plating bath to be used, the required plating thickness, and the like. For example, it is preferable to use an insoluble anode such as stainless steel, a titanium platinum plate, or iridium oxide as the anode material. Further, as suitable plating conditions, bath temperature: 20 to 50 ° C., current density: 0.1 to 5.0 A / dm ² , treatment time: 1 to 1440 seconds, pH: 3.0 to 7.0 are exemplified. can do.

≪PCB terminal≫
FIG. 2 is a schematic perspective view showing an example of the PCB terminal of the present invention. The PCB terminal 1 has a comb-teeth shape in which a plurality of substantially square columnar male terminals 4 are arranged side by side at the end of the metal base material 2. The PCB terminal 1 can be efficiently manufactured by using the method for manufacturing a PCB terminal of the present invention.

Basically, the metal base material 2 and the male terminal 4 are made of the same material and are not particularly limited as long as they have electrical conductivity. For example, aluminum and aluminum alloy, iron and iron alloy (for example, iron-nickel alloy). , Titanium and titanium alloys, stainless steel, copper and copper alloys, etc., but among them, copper or brass is preferable because of its excellent electrical conductivity, thermal conductivity and spreadability.

A cross-sectional view taken along the line AA of the terminal 4 is shown in FIG. In the male terminal 4, a nickel plating layer 12 is formed on the surface of the metal base material 2, and a thick gold plating layer 14 is formed on the surface of the nickel plating layer 12 via a thin gold plating layer (not shown). It is formed. By forming the thin gold plating layer, the adhesion between the nickel plating layer 12 and the thick gold plating layer 14 can be sufficiently ensured.

The thick gold plating layer 14 is formed only on the front surface and the back surface of the male terminal 4, and is not formed on both side surfaces. The thin gold plating layer may be formed on the entire surface of the nickel plating layer 12, or may be formed only on the front surface and the back surface of the male terminal 4 on which the thick gold plating layer 14 is formed.

The thickness of the thickened gold plating layer 14 is 0.2 μm to 1.0 μm. By setting the thickness of the thick gold plating layer 14 to 0.2 μm or more, the electrical characteristics and durability of gold can be fully utilized, and by setting it to 1.0 μm or less, the amount of gold used can be reduced. In addition to being able to suppress it, deterioration of productivity can be suppressed. The thickness of the thickened gold plating layer 14 is more preferably 0.4 μm to 0.8 μm, and most preferably 0.5 μm to 0.7 μm.

Further, the thickness of the thin gold flash plating layer is preferably more than 0 and 0.1 μm or less. The thickness of the thin gold flash plating layer is more preferably 0.08 μm or less, and most preferably 0.06 μm or less. By setting the thickness of the thin gold flash plating layer to 0.1 μm or less, it is possible to suppress an increase in the amount of gold used and a deterioration in productivity.

In the PCB terminal 1, since the thick gold plating layer 14 is formed on the front surface and the back surface of the male terminal 4 that comes into contact with the female terminal at the time of mating, the thick gold plating layer 14 has excellent wear resistance and low. Electric resistance and good heat resistance can be utilized, and the conductivity and durability required for PCB terminals can be sufficiently ensured. On the other hand, the thick gold plating layer 14 is not formed on both side surfaces of the male terminal 4, and the amount of gold used is suppressed to the minimum necessary.

Further, in the PCB terminal 1, since the nickel plating layer 12 exists between the metal base material 2 and the thick gold plating layer 14, the nickel plating layer 12 diffuses and reacts with gold and the elements contained in the metal base material 2. Functions as a barrier layer to prevent. That is, the presence of the nickel plating layer 12 between the metal base material 2 and the thick gold plating layer 14 is due to the diffusion of the element contained in the metal base material 2 and gold and the formation of an intermetallic compound due to the reaction. , It is possible to suppress the brittleness of the thickened gold plating layer 14.

Further, by forming the outermost surface of the front surface and the back surface of the male terminal 4 in which sliding wear is remarkable as a thick gold-plated layer 14, serious problems such as ignition and electric shock caused by metal pieces scattered due to sliding wear are serious. Accidents can be prevented.

Although the typical embodiments of the present invention have been described above, the present invention is not limited to these, and various design changes are possible, and all of these design changes are included in the technical scope of the present invention. Will be.

<< Example >>
A copper metal base material in the shape of a comb-shaped PCB terminal having a plurality of substantially square pillar-shaped male terminals was used as a pretreatment, and the material to be plated and the SUS plate were placed in an alkaline degreasing solution, and the material to be plated was used as a cathode. Using a SUS plate as an anode, electrolytic degreasing is performed at a voltage of 3 V for 30 seconds, and after cleaning, a copper strike plating bath containing 30 g / L cuprous bluish copper, 20 g / L free bluish potassium, and 15 g / L caustic potassium. The anode material is an electrolytic copper plate, and the cathode material is a metal substrate after cleaning treatment. Copper strike plating treatment (base strike plating treatment) is performed for 10 seconds under the conditions of bath temperature: 35 ° C. and current density: 1A / dm ² . provided. Then, using a nickel plating bath containing 300 g / L nickel sulfamate, 5 g / L nickel chloride hexahydrate, 10 g / L boric acid, and 0.2 g / L sodium lauryl sulfate, the anode material was prepared. Sulfa nickel plate and cathode material are used as a metal substrate after copper strike plating, and nickel plating is applied for 200 seconds under the conditions of bath temperature: 50 ° C. and current density: 2A / dm ² , and the entire surface of the terminal has a thickness of about 1 μm. A nickel-plated layer was formed (first step).

Then, using a gold plating bath containing 10 g / L potassium gold cyanide, 50 g / L potassium citrate, 10 g / L potassium hydroxide, and 2 g / L cobalt sulfate, the anode material was a titanium platinum plate and the cathode material. As a metal substrate after nickel plating, gold plating flash treatment was performed for 2 seconds under the conditions of bath temperature: 40 ° C. and current density: 0.5 A / dm ² , and gold with a thickness of 0.1 μm was applied to the entire surface of the nickel plating layer. A plated flash layer was formed. Next, after drying the metal substrate to be plated using a dryer, masking was performed on the front surface and the back surface of the male terminal with masking tape (second step).

Next, using a negative electrodeposition resist, the resist was applied for 30 seconds at a bath temperature of 35 ° C. and a constant voltage of 30 V. Then, the masking tape was peeled off and exposed to UV light (mercury lamp) for 100 seconds to cure the resist (third step). The heat generated during the resist exposure was quickly removed by air cooling.

Then, in order to prevent the resist from peeling off, a cleaning treatment was performed using a dipping treatment instead of an electrolytic treatment. After the cleaning treatment, a gold plating bath containing 10 g / L potassium gold cyanide, 50 g / L potassium citrate, 10 g / L potassium hydroxide, and 2 g / L cobalt sulfate was used, and the anode material was titanium platinum. The plate and cathode material are used as the material to be plated after the resist treatment, and the gold plating treatment is performed under the conditions of a bath temperature of 40 ° C. and a current density of 4 A / dm ² for 30 seconds, and the resist is peeled off using a stripping solution. As a result, a gold-plated layer having a thickness of 0.5 μm was formed only on the front surface and the back surface of the terminal (fourth step) to obtain a PCB terminal according to an embodiment of the present invention.

FIG. 4 shows an overview photograph of the tip of the male terminal of the PCB terminal obtained. A thick gold-plated layer with excellent wear resistance, conductivity, slidability and low friction is formed only on the front and back surfaces of the male terminal, while minimizing the amount of expensive gold used. , A highly reliable PCB terminal has been obtained.

1 ... PCB terminal,
2 ... Metal substrate,
4 ... Male terminal,
12 ... Nickel plating layer,
14 ... Thick gold-plated layer.

Claims (2)

It is a comb-shaped PCB terminal that has a plurality of male terminals in the shape of a substantially square pillar.
A nickel-plated layer having a thickness of 0.3 μm to 4.0 μm is provided on the entire surface of the male terminal.
A thin gold plating layer having a thickness of more than 0 and a thickness of 0.1 μm or less is formed on the entire surface of the nickel plating layer.
A thick gold plating layer having a thickness of 0.2 μm to 1.0 μm is formed only on the front surface and the back surface of the nickel plating layer formed on the front surface and the back surface of the male terminal.
PCB terminal featuring. The male terminal is made of copper or a copper alloy.
The PCB terminal according to claim 1.

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