JP2006161127A - Electronic material suitable for insertion type connection terminal and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce an electronic material with tin based plating suitable for an insertion type connection terminal which can prevent the generation of insertion whiskers caused by pressure at the time of insertion in an insertion type connection terminal. <P>SOLUTION: An electrically conductive substrate composed of copper or a copper alloy is subjected to nickel plating as a substrate and flash copper plating with a thickness of 0.05 to 0.5 μm in order, and is next subjected to tin or tin alloy plating. In the obtained electronic material with the tin based plating, with the lapse of time or under reflowing at ≥210°C, the flash copper plating layer is mutually diffused with the nickel plating layer as a substrate, so as to be changed into a barrier layer composed of a copper-nickel alloy layer, and prevents the growth of acicular or columnar crystals caused by intermetallic compounds in the tin or tin alloy plating film. By the alloy layer considered as a solid solution, the generation of insertion whiskers can be effectively suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic material suitable for a fitting-type connection terminal and a manufacturing method thereof. According to the present invention, there is provided an electronic material capable of forming a fitting type connection terminal in which the generation of whiskers (fitting whiskers) due to pressure during insertion of the fitting type connection terminal is suppressed.

  Fitting type connection terminals used for electrical wiring connectors of automobiles and various electric / electronic devices have a structure in which tin plating (or tin alloy plating) is applied to the surface of a conductive substrate made of metal such as copper or copper alloy have. The main purpose of the tin plating is that the tin-plated surface oxide film of the terminal portion is destroyed by friction when the terminals are connected, so that fresh tin adheres to stably obtain a low contact resistance. The contact resistance of the tin plating thus obtained is so small that it is comparable to expensive silver plating. Tin plating is also excellent in solderability when it is subsequently soldered, and has the advantages that it can be brightly plated and has a beautiful appearance.

  As a general problem of tin plating, it is well known that a whisker-like precipitate called whisker is generated due to an environmental change after plating, which causes a short circuit or the like. Hereinafter, this whisker is referred to as a timed whisker. Temporal whiskers are considered to be caused by the stress of the tin plating film, and in order to release the stress of the plating film, a heat treatment called reflow is often performed after tin plating.

In order to suppress whiskers, it is known that it is effective to perform base nickel plating on the surface of a copper or copper alloy substrate (see Non-Patent Document 1).
When the conductive substrate is a zinc-containing copper alloy such as brass, zinc diffuses from the substrate into the tin plating film, and a zinc oxide layer is formed on the surface of the plating film. In particular, zinc diffusion tends to occur during reflow. The zinc oxide layer formed on the plating surface reduces the corrosion resistance of the plating film and causes discoloration, and causes a significant increase in contact resistance. Underlying nickel plating is also used as a barrier layer for preventing components such as zinc from diffusing from the substrate into the tin plating film.

In Patent Document 1, a nickel plating layer, a copper plating layer, and a tin plating layer are formed in this order on the surface of a copper-zinc alloy base material, and then heat treatment is performed. Describes a method for manufacturing a fitting-type connection terminal in which a Cu ₆ Sn ₅ intermetallic compound is formed in the vicinity of the interface. The nickel plating layer is a barrier layer that prevents diffusion of zinc from the base material. The reason why the copper plating layer is formed on the nickel layer is to form a Cu ₆ Sn ₅ intermetallic compound in the vicinity of the interface between the copper plating layer and the tin plating layer. The heat treatment for generating the Cu ₆ Sn ₅ intermetallic compound is performed at 150 to 170 ° C. When the heat treatment temperature exceeds 170 ° C., the intermetallic compound is changed to columnar Cu ₃ Sn, and the surface unevenness is increased to increase the contact resistance of the terminal.

Patent Document 2 discloses a connector with tin plating in which a copper-tin alloy layer and a surface tin or tin alloy plating layer are formed on a base made of copper or a copper alloy, and an organic lubricating film is further formed thereon. Electronic materials for use are described. The copper-tin alloy layer is formed by subjecting tin plating and copper or copper alloy plating layer formed thereunder to a heat treatment, and may have a nickel layer under the copper-tin alloy layer. . Paragraph 0006 states that the copper-tin alloy layer is entirely or mostly composed of the η phase of a copper-tin intermetallic compound. The reflow heat treatment is performed at 230 to 600 ° C.
26th edition of “Plating Technology for Environment” JP 11-135226 A (claims, paragraphs 0010, 0029, 0030) JP 2003-183882 A (claims, paragraphs 0006 and 0012)

  Fitting type connection terminals manufactured from an electronic material having a tin or tin alloy plating film on the surface of a conductive substrate, even when the prevention of whisker over time by reflow etc. There is a problem in that whiskers called fitting whiskers are generated in the terminal portion to which is added, causing a short circuit.

  This invention makes it a subject to provide the electronic material with a tin plating suitable for a fitting type connection terminal which can prevent generation | occurrence | production of a fitting whisker.

  According to the present invention, after the nickel plating and the flash copper plating are performed in this order on the surface of the conductive substrate, the above problem can be solved by forming a tin or tin alloy plating film.

  If the copper plating layer formed on the nickel plating layer is a very thin layer by flash plating, the copper-tin metal at the interface between the copper plating layer and the tin plating film as described in Patent Documents 1 and 2 It was found that the copper plating layer was alloyed by interdiffusion with the underlying nickel plating layer, and the copper plating layer was changed to a copper-nickel alloy layer, instead of forming an intercalation compound. This change can be caused by heat treatment, but it occurs with time even without heat treatment.

  By this change, an electronic material having a nickel layer, a copper-nickel alloy layer, and a tin or tin alloy plating film in this order on the surface of the conductive substrate is obtained. The copper-nickel alloy layer functions as a barrier layer that prevents the components of the conductive substrate and the nickel of the base plating layer from diffusing into the tin or tin alloy plating film on the surface to alter the plating film. And when the barrier layer which consists of this copper-nickel alloy layer was formed under the tin or tin alloy plating film, it turned out that generation | occurrence | production of the fitting whisker at the time of insertion of a fitting type connection terminal can be prevented.

  Here, the present invention, in one aspect, is an electronic material with tin plating having a tin or tin alloy plating film on a surface of a conductive substrate via a base nickel layer and a barrier layer made of a copper-nickel alloy. . In this tin-based electronic material with plating, the tin or tin alloy plating film substantially does not contain needle-like or columnar crystals.

  In another aspect, the present invention provides a tin-plated plating having a base nickel plating layer, a flash copper plating layer having a thickness of 0.05 to 0.5 μm, and a tin or tin alloy plating film in this order on the surface of the conductive substrate. It is an electronic material.

The conductive substrate is preferably made of copper or a copper alloy.
According to the invention,
A fitting connection terminal made of the electronic material with tin plating, and a conductive base, followed by a nickel plating of a base and a flash copper plating of 0.05 to 0.5 μm in this order, and then tin or tin A method for producing an electronic material with tin plating, characterized by performing alloy plating,
Is also provided. This manufacturing method may further include a step of performing a heat treatment at a temperature of 210 ° C. or higher after the tin or tin alloy plating.

  The electronic material with tin plating according to the present invention can prevent the occurrence of fitting whiskers, and is particularly suitable as a fitting-type connection terminal, but the application is not limited thereto. For example, it can be used for connection terminals, switches, relays and the like that are not of a fitting type.

  As described above, an underlying nickel plating layer is formed between the base and the tin-based plating film for the purpose of suppressing whisker or preventing diffusion from the conductive base on the tin-based plating film made of tin or tin alloy. Things have been done.

However, as a result of the study of the underlying nickel plating by the present inventors, the underlying nickel plating diffuses into the upper tin-based plating film during the heat treatment such as reflow (or during a long period of time) and forms an alloy. Turned into a tin-nickel alloy layer, and it was found that a tin-nickel alloy layer was formed at the interface between the substrate and the tin-based plating film. It is considered that this alloy layer is actually composed of a tin-nickel intermetallic compound (Ni _x Sn _y ). In that case, the apparent hardness of the tin-based plating film is remarkably increased, and fitting whiskers are likely to occur due to the pressure at the time of insertion when the fitting type connection terminal is used.

This point will be described in more detail. A tin-nickel alloy layer made of a tin-nickel intermetallic compound represented by Ni _x Sn _y formed at the interface is schematically shown in the figure after reflow in FIG. It takes the form of needles or columns and grows in the thickness direction of the tin-based plating film. The formation of needle-like or columnar crystals (hereinafter simply referred to as needle-like crystals) is also observed in the cross-sectional micrograph shown in FIG. From this photograph, it can be seen that some needle crystals grow until they penetrate the tin-based plating film in the thickness direction. The reason why such needle-like crystals are generated is presumed as follows.

Nickel diffuses more easily in tin than in copper. Accordingly, during reflow or aging, nickel diffuses into the upper tin-based plating film, not the lower copper-based substrate. In this case, since the diffusion of nickel proceeds along the grain boundary of the tin-based plating film as schematically shown in FIG. 1 (a), the tin-nickel alloy layer (Ni _x Sn _y ) generated by the diffusion is used. Is in the form of needles or columns. From the known binary phase diagram of nickel and tin, Ni ₃ Sn, Ni ₃ Sn ₂ and Ni ₃ Sn ₄ are given as specific examples of Ni _x Sn _y .

  When a part of the needle crystal penetrates the tin-based plating film, the corrosion resistance of the plating film is lowered, the surface unevenness becomes very large, and the contact resistance is remarkably increased. In addition, when used as a fitting-type connection terminal, fitting whiskers are likely to occur because the acicular crystals are harder than the tin plating film and the apparent hardness of the plating film is high. Conceivable.

  On the other hand, in the present invention, as shown in FIG. 2, a base nickel plating layer is formed on the surface of the conductive substrate, and flash copper plating is further formed thereon to form an extremely thin copper plating layer. Then, a tin-based plating film is formed thereon. In the substrate having the three plating layers, the nickel plating layer is alloyed with the flash copper plating layer thereon by reflow (heat treatment) or aging. Thereby, the flash copper plating layer disappears, and a copper-nickel alloy layer having a thickness larger than that of the flash copper plating layer is generated between the nickel plating layer and the tin-based plating film.

  In doing so, nickel may preferentially alloy with the upper flash copper plating layer, although there is some possibility of alloying with the underlying copper of the base. The reason is presumed as follows.

The flash copper plating layer deposited on the nickel plating layer forms copper hydroxide [Cu (OH) ₂ or CuOH] and is not in a stable state, and thus is adsorbed to nickel. Nickel adsorbed by copper hydroxide does not have the activity required for diffusion, does not diffuse into the tin-based plating film, and cannot grow acicular intermetallic compounds. On the other hand, since copper hydroxide adsorbed on nickel is unstable, when energy is acquired during heat treatment or aging, copper is alloyed with nickel to stabilize. If the copper plating layer is not a flash plating but a normal thickness copper plating, the copper will self-stabilize and behave as a mere metallic copper similar to the base, so it will not adsorb to the nickel and the nickel will not diffuse. It becomes easy. That is, nickel is preferentially alloyed with the upper copper layer only when the copper plating layer is a flash copper plating layer having the above thickness.

  As can be seen from the binary phase diagram shown in FIG. 4, nickel and copper form a completely stable solid solution in the entire composition range. Therefore, it is estimated that the copper-nickel alloy layer produced | generated by alloying with a flash copper plating layer and a nickel layer consists of a copper-nickel solid solution. The solid solution is a state in which the metals are completely mixed at the crystal level and are like one metal.

  Therefore, in the present invention, it is considered that the copper-nickel alloy layer formed on the lower side of the tin-based plating film is made of a solid solution that behaves in the same manner as a metal, and has a needle-like crystal form like the tin-nickel alloy layer described above. Don't take it. This point is also apparent from the cross-sectional micrograph of FIG. 3 (b) showing the film structure of the tin-based plated material of the present invention. As seen in this photograph, the tin-nickel alloy layer exists in a layered form that spreads thinly between the underlying nickel plating layer and the tin-based plating film on the surface, as shown in FIG. No crystallites are seen.

  In the conventional film structure of FIG. 3 (a), many needle crystals grow so as to penetrate into the tin-based plating film, and the tin-based plating film is altered. Various problems such as deterioration and generation of fitting whiskers occur. On the other hand, in the film structure of the present invention shown in FIG. 3 (b), the tin-based plating film is maintained in a healthy state, so that the corrosion resistance and the contact resistance are not deteriorated.

  In addition, when a copper-nickel alloy layer is present between the tin-based plating layer and the conductive base, generation of fitting whiskers is prevented when the fitting-type connection terminal is inserted. The reason for this is that this copper-nickel alloy layer is a solid solution and is soft and tough like metal, so it easily absorbs stress due to the pressure at the time of insertion of the mating connection terminal, causing the occurrence of mating whiskers. And the copper-nickel alloy layer functions as a barrier layer that prevents the formation of a tin-nickel alloy (needle-like crystal) due to the diffusion of nickel and leads to the generation of fitting whiskers. It is considered that the generation of fitting whiskers can be effectively prevented because the generation of crystallites can be prevented.

  Since the copper-nickel alloy is widely distributed as cupronickel (white copper) and also as a resistance material constantan, electrical characteristics have been examined in detail. Therefore, it is easy to grasp the characteristics of the copper-nickel alloy functioning as a barrier layer in the present invention.

  Since the flash copper plating layer is very thin, even if the flash copper plating layer is completely changed to a copper-nickel alloy layer, the nickel layer remains in the lower layer. This nickel layer can prevent the diffusion of zinc from the substrate to the tin-based plating film even when the conductive substrate contains an alloy element such as zinc.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the fitting whisker at the time of insertion of a fitting type | mold connection terminal can be prevented, maintaining a tin-type plating film healthy. Since the uppermost tin-based plating film does not undergo alteration such as the formation of acicular crystals, the corrosion resistance does not deteriorate, and the good corrosion resistance inherent to the tin-based plating film is maintained. Further, when the intermetallic compound is exposed on the surface of the tin-based plating film, the surface unevenness increases and the contact resistance of the material increases remarkably, but such an increase in contact resistance can also be avoided.

The tin-plated electronic material suitable for the fitting-type connection terminal of the present invention and the manufacturing method thereof will be described more specifically. However, the following description is only an example and does not limit the present invention.
In the present invention, the composition of the conductive substrate is not particularly limited as long as the conductivity is sufficient. In the case of a fitting type connection terminal, the base is generally copper or a copper alloy. A typical example of the copper alloy is a copper-zinc alloy such as brass. More broadly, it may be a copper alloy containing one or more alloy elements selected from zinc, nickel, silicon, magnesium, chromium, iron, tin, phosphorus and zirconium. The entire conductive substrate may be made of copper or a copper alloy, or may be made of only the surface of copper or a copper alloy, such as a flexible substrate.

  The substrate may be processed into the shape of the fitting type connection terminal in advance. In general, the fitting type connection terminal is composed of a male type and a female type terminal. For example, as shown in FIG. 5, the male terminal is formed of a substrate such as a flexible substrate, and the female terminal can be formed inside the connector. In addition to the substrate, the male terminal can be, for example, a connector or a lead frame. The female terminal may take other forms, but is typically formed inside the connector.

  On the substrate, a nickel plating layer is formed by applying a base nickel plating. The thickness of the nickel plating layer is preferably in the range of 0.1 to 4 μm. Therefore, it is preferable to form the nickel plating layer by electroplating capable of forming a plating film having such a thickness at a time. As the electroplating bath, any of a known Watt bath, chloride bath, nickel sulfamate bath and the like can be used, but a nickel sulfamate bath is preferred. The thickness of the nickel plating layer is preferably at least twice the thickness of the flash copper plating layer formed thereon, more preferably at least five times.

  Next, flash copper plating (short-time electroplating) is performed to form a thin copper plating layer on the nickel plating layer. The flash copper plating layer has a thickness of 0.05 to 0.5 μm. If the flash copper plating layer is thinner than 0.05 μm or thicker than 0.5 μm, the effect of suppressing the fitting whisker cannot be sufficiently obtained. The copper plating bath is not particularly limited, but a copper sulfate plating bath is preferable.

  Thereafter, tin or tin alloy plating is performed to form a tin-based plating layer made of tin or tin alloy plating on the flash copper plating layer. The thickness of the tin-based plating layer is preferably in the range of 0.5 to 15 μm. Tin-based plating is also generally performed by electroplating, and as the plating bath, for example, a borofluoride bath, an organic acid salt bath, or the like is used, but it is not limited thereto. The tin-based plating can also be a bright plating containing a brightening agent.

  In the case where the tin plating is tin alloy plating, examples of the tin alloy include an alloy of tin and one or more selected from copper, bismuth, silver, zinc, and indium. A preferred tin-based plating is a tin-copper alloy. Since the tin-copper alloy plating film is slightly harder than the tin plating film, the insertion force of the fitting type connection terminal can be reduced. However, even if the tin-based plating film is pure tin or an alloy of metal other than tin and copper, the fitting whisker suppressing effect of the present invention can be obtained similarly.

  When the base is processed into the shape of the fitting type connection terminal in advance, when the shape of the base is very small, the above-described electroplating can be performed by barrel plating. In that case, a plating bath suitable for barrel plating can be selected.

  In this way, the electronic material with tin plating according to the present invention having the base nickel plating layer, the thin flash copper plating layer, and the tin plating layer on the conductive substrate is obtained. The electronic material with tin plating having the flash copper plating layer can be used for fitting connection terminals and other applications without reflowing as it is. Even in such a case, as described above, the flash copper plating layer is alloyed with the underlying nickel layer due to a change with time, and is changed to a copper-nickel alloy layer, so that the above-described effect of preventing fitting whiskers can be obtained.

  When reflow is not performed, in order to prevent the occurrence of whisker over time of the tin-based plating film, other means for suppressing whisker over time other than reflow (eg, changing the brightener of the tin-based plating bath) may be employed.

  In order to prevent the occurrence of aging whiskers, preferably, after the tin-based plating film is formed, reflow (heat treatment) is performed to release the distortion of the tin-based plating layer. Simultaneously with this reflow, the flash copper plating layer is alloyed with the underlying nickel plating layer to form a copper-nickel alloy layer, thus preventing the occurrence of fitting whiskers. However, since the copper plating layer is very thin compared to the nickel layer, even if copper is completely alloyed with nickel, most of the nickel layer remains unalloyed, and there is a copper-nickel alloy layer on it. . As described above, this copper-nickel alloy layer is considered to be a solid solution having the same properties as metal as seen from the phase diagram, and functions as a diffusion prevention layer and at the same time prevents the occurrence of fitting whiskers.

  The heat treatment conditions are preferably selected so that a thin copper plating layer formed by flash plating is completely alloyed with nickel, and it is particularly effective for the purpose of the present invention to be 210 ° C. or higher. The upper limit of the temperature is not particularly limited, but considering the cost, it is advantageous to set it to 310 ° C. or lower. A preferable heat treatment temperature is in the range of 210 to 265 ° C. The heat treatment time will usually be sufficient in the range of 100 to 500 seconds. A preferable heat treatment time is 200 to 300 seconds.

  Thus, a tin-plated electronic material having a copper-nickel alloy layer on a conductive substrate, preferably via a nickel layer, and having a tin-based plating film made of tin or a tin alloy thereon is produced. The Since the copper-nickel alloy layer functions as a barrier layer for preventing the diffusion of nickel into the tin-based plating film, the tin-based plating film is kept healthy, and this plating film is a needle-like or columnar nickel-tin intermetallic compound. Is substantially not contained.

  In Patent Document 2, when a reflow is performed after forming a base nickel plating layer, a copper plating layer, and a tin plating film on a base, copper in the copper plating layer diffuses into the tin-based plating layer during the reflow, It is described that a layer made of a copper-tin intermetallic compound is formed between the copper plating layer.

  In the present invention, the copper plating layer is not an upper tin-based plating film, but a copper-nickel alloy layer is generated by mutual diffusion with the lower nickel plating layer. The reason is that, as described above, the copper plating layer is an ultra-thin flash copper plating layer that is adsorbed in an unstable state on nickel, and is therefore considered to be alloyed with nickel. .

(Example 1)
A base consisting of a copper plate (20 × 50 mm) having a thickness of 0.2 mm is electroplated to form a base nickel plating layer (thickness 1 μm, sulfamate bath), a flash copper plating layer (thickness 0.1 μm, sulfate bath), tin -A copper alloy plating layer (thickness 3 µm, copper content 1.5 mass%, organic acid salt bath) was formed in order. Thereafter, this substrate was put in an oven at 250 ° C. and heat-treated for 250 seconds.

  A cross-sectional photomicrograph of the plating layer thus formed on the substrate is shown in FIG. As can be seen from this photograph, the plating film on the substrate has a structure in which a nickel layer, a copper-nickel alloy layer, and a tin-copper alloy plating layer are laminated in order from the bottom, and acicular crystals are seen. There wasn't. The surface tin-copper alloy plating layer maintained a dense and healthy state.

(Comparative Example 1)
For comparison, a base nickel plating layer and a tin-copper alloy plating layer were formed on the substrate in the same manner as in Example 1 except that the flash copper plating layer was not formed, and heat treatment was performed. A cross-sectional photomicrograph of the plating layer thus formed on the substrate is shown in FIG. As can be seen from this photograph, a large number of needle-like crystals (estimated to be composed of a tin-nickel intermetallic compound <Ni _x Sn _y >) grow on the substrate and protrude into the tin-copper alloy plating layer. It was. A part of this crystal completely penetrated the surface tin-copper alloy plating layer and appeared on the plating surface.

  As a result of examining the Vickers hardness (Hv) of the plating surface of the electronic material with tin plating manufactured in Example 1 and Comparative Example 1, it was Hv 16.88 in Example 1, whereas Hv 34. 54, the hardness was more than doubled. In Comparative Example 1, since needle-like crystals made of an intermetallic compound are deposited so as to penetrate into the tin-based plating film, the lower part of the tin-based plating film is a copper-nickel alloy layer made of a solid solution. Compared to Example 1, it is considered that the apparent hardness of the plating film was increased.

  Further, with respect to the electronic material with tin plating of Example 1 and Comparative Example 1, a probe made of stainless steel (SUS316) having a tip diameter of 1 mm was vertically applied to the plating surface and pressed from above with a force of 300 gW for 500 hours. The occurrence of mating whiskers was examined. Photographs showing the results are shown in FIG. 6 (a) (Comparative Example 1) and FIG. 6 (b) (Example 1).

In the case of Comparative Example 1 shown in FIG. 6A, fitting whiskers were remarkably generated, whereas in the case of Example 1 shown in FIG. 6B, no fitting whiskers were generated.
(Comparative Example 2)
Except for the point that the thickness of the flash copper plating layer was increased to 1 μm, three types of plating (nickel plating, copper plating, and tin-copper alloy plating) and reflow were performed in the same manner as in Example 1, and tin-based plating was performed. The attached electronic material was manufactured.

When the cross-section of this electronic material was observed with a microscope to examine the film structure, a large number of needle-like crystals were observed in the tin-copper alloy plating film as shown in FIG. That is, when the thickness of the copper plating interposed between the nickel layer and the tin-based plating film is greater than 0.5 μm, the barrier effect due to the copper-nickel alloy layer cannot be obtained satisfactorily, and Ni _x Sn _y grows. Will happen again. However, as shown in FIG. 2 (a), the acicular crystals did not grow to the extent that they penetrate the tin-copper alloy plating film.

  When this electronic material was subjected to a fitting whisker generation test in the same manner as described above, the generation of fitting whiskers was clearly confirmed.

It is explanatory drawing which shows typically the condition after the spreading | diffusion by the reflow after the plating in the prior art which formed base nickel plating and tin-type plating (in the figure, tin-copper alloy plating) on the copper base | substrate. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view schematically showing the situation immediately after plating and after diffusion by reflow when a base nickel plating, flash copper plating, and tin-based plating (tin-copper alloy plating in the figure) are formed according to the present invention. is there. FIG. 3 is a cross-sectional photomicrograph (× 4000) showing the film structure after reflow. FIG. 3 (a) shows the conventional technique similar to FIG. 1, and FIG. 3 (b) shows the present invention similar to FIG. In this case, FIG. 3 (c) shows a comparative example in which the copper plating is too thick. A nickel-copper binary system phase diagram is shown. It is explanatory drawing which shows typically an example of the structure of a fitting type connection terminal, and the generation | occurrence | production position of a fitting whisker. It is a figure which shows the generation | occurrence | production state of the fitting whisker after the terminal insertion at the time of using as a fitting type connection terminal, FIG. 6 (a) shows the case of a prior art, FIG.6 (b) shows the case of this invention, respectively. .

Claims (7)

  An electronic material with tin-based plating in which the generation of fitting whiskers is suppressed, which has a tin or tin alloy plating film on the surface of a conductive substrate via a base nickel layer and a barrier layer made of a copper-nickel alloy.   The electronic material with tin-based plating according to claim 1, wherein the tin or tin alloy plating film does not substantially contain needle-like or columnar crystals.   Electron with tin plating on which the surface of the conductive substrate has a base nickel plating layer, a flash copper plating layer having a thickness of 0.05 to 0.5 μm, and a tin or tin alloy plating film in this order, and generation of fitting whiskers is suppressed. material.   The electronic material with tin plating according to any one of claims 1 to 3, wherein the conductive substrate is made of copper or a copper alloy.   The fitting type connection terminal which consists of an electronic material with a tin system plating in any one of Claims 1-4.   The formation of fitting whiskers, characterized in that a conductive base is subjected to a base nickel plating and a flash copper plating with a thickness of 0.05 to 0.5 μm in this order, and then tin or tin alloy plating is suppressed. Manufacturing method of electronic material with tin plating. The method of Claim 6 which heat-processes at the temperature of 210 degreeC or more after tin or a tin alloy plating.

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