JP2009242925A - Sn-PLATED COPPER OR COPPER ALLOY, AND PRODUCING METHOD FOR THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Sn-plating material having a Sn-plating film containing carbon particles in which a fitting work can be performed with low inserting force and which causes less powder fall of the carbon particles during press work. <P>SOLUTION: The copper or a copper alloy subjected to the Sn-plating has a plurality of protrusions formed by condensation of the carbon particles on its surface. The average value of an aspect ratio of the protrusions when viewed from the cross section is 0.2-0.6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an Sn plating material that is suitable as a conductive spring material for electronic components, particularly connectors and terminals. Moreover, this invention relates to the manufacturing method of such Sn plating material.

  In recent years, with the increase in the number of circuits of electronic / electrical components, the number of connectors for supplying electric signals to the circuits has been increasing. Sn plating material is excellent in electrical conductivity, corrosion resistance and solderability, and it is useful as a member for connectors, but because of its softness, it has a gas tight (airtight) structure that adheres males and females at connector contacts. Therefore, the insertion force of the connector per pole is higher than that of a connector constituted by gold plating or the like. For this reason, an increase in connector insertion force due to the increase in the number of connectors is a problem. At present, the work of fitting the connector is almost done manually, and when the insertion force of the connector is increased, a burden is placed on the worker on the assembly line, and the work efficiency is lowered. For this reason, reduction of the insertion force of Sn plating material is strongly desired.

  In order to solve this problem, a technique for reducing the insertion force by including carbon in the Sn plating layer is known.

  Japanese Patent No. 2997135 (Patent Document 1) discloses a tin or tin alloy-plated copper that requires a low friction coefficient and a small terminal insertion force by controlling the amount of C and the plating thickness in the tin or tin alloy plating film. It is described that alloys can be obtained. C in the plating film is said to be controllable by appropriately controlling the type and amount of brightener in the plating bath, electrolysis conditions (particularly current density), and the like.

  JP 2006-265642 A (Patent Document 2) discloses a composite material containing carbon particles in a tin layer by performing electroplating using a tin plating solution to which carbon particles and an aromatic carbonyl compound are added. It is described that a tin-plated material having a very low friction coefficient can be produced by forming a film made of And it is supposed that by adding an aromatic carbonyl compound to the tin plating solution, island-shaped protrusions containing a plurality of carbon particles spaced apart from each other are formed on the surface of the plating film. In the Examples, it is described that 20 g / L of scaly graphite particles having an average particle diameter of 3.4 μm or 5 μm and benzaldehyde 30 mL / L were added to the tin plating solution.

Furthermore, JP 2007-2285 A (Patent Document 3) describes the concentration of carbon particles in a tin plating solution when electroplating is performed using a tin plating solution to which carbon particles and an aromatic carbonyl compound are added. A film made of a composite material in which carbon particles are dispersed in a tin layer was formed on the material by indenting by making it less than 20 g / L, preferably 1 to 10 g / L, more preferably 5 to 10 g / L. Even in this case, it is described that a tin plating material having a very low coefficient of friction with other types of tin plating materials such as a tin reflow material can be manufactured. In Examples, it is described that 20 g / L or 10 g / L of flaky graphite particles having an average particle size of 3.4 μm and 30 mL / L of benzaldehyde were added to a tin plating solution.
Japanese Patent No. 2971035 JP 2006-265642 A JP 2007-2285 A

  However, the method of adjusting the C content by controlling the brightener as in Patent Document 1 does not sufficiently reduce the insertion force. Moreover, although the method of forming the film | membrane which consists of a composite material with which the carbon particle was disperse | distributed in a tin layer like patent document 2 and 3 on a raw material is effective, since the protrusion formed on Sn plating film | membrane becomes sharp. For example, it has been found that when processed into a terminal and fitted as a terminal, the protrusion collapses and carbon particles are likely to fall off.

  Therefore, the present invention provides a copper or copper alloy having a Sn plating film containing carbon particles, and capable of performing a fitting operation with a low insertion force and having less powdered carbon particles. Is one of the issues. Another object of the present invention is to provide a method for producing such copper or copper alloy.

  The present inventor conducted extensive studies to solve the above problems, and found that it is effective to optimize the shape of the protrusion formed by the aggregation of carbon particles on the surface of the Sn plating film. Specifically, it is effective to adjust the aspect ratio of each protrusion, that is, the ratio of the height of the protrusion to the width of the protrusion to 0.2 to 0.6 on average. In particular, the aspect ratio can be controlled by adjusting the particle size of the carbon particles forming the protrusions. Furthermore, by adjusting the size of the protrusions, the area ratio of carbon (C) on the surface of the Sn plating, etc., an Sn plating material excellent in the balance of insertion / removability, solderability, and powder falling characteristics can be obtained.

  The present invention completed on the basis of such knowledge is, in one aspect, copper or copper alloy plated with Sn, and the Sn plating has a plurality of protrusions formed by agglomerating carbon particles on the surface thereof, The protrusion is copper or a copper alloy having an average aspect ratio of 0.2 to 0.6 when observed from a cross section.

  In still another embodiment of the copper or copper alloy according to the present invention, the average particle diameter of the protrusions is 1 to 10 μm when observed from the Sn plating cross section.

  In still another embodiment of the copper or copper alloy according to the present invention, the area occupied by C is 10 to 50% when observed from the Sn plating surface.

  In still another embodiment of the copper or copper alloy according to the present invention, the surface roughness is 1 to 6 μm.

  In another aspect, the present invention is an electronic component comprising the copper or copper alloy according to any one of claims 1 to 8.

  In still another aspect of the present invention, 0.1 to 5 g / L of carbon particles having an average particle diameter of 0.05 to 1.0 μm and 0.1 or more of one or more aldehyde compounds in total are 0.1. It is the method for manufacturing copper or a copper alloy including electroplating to copper or a copper alloy using Sn plating bath which added 10g / L.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to obtain Sn plating material which is excellent in insertion / extraction property and has few powder fall-off.

1. Copper or copper alloy used as a copper or copper alloy plating base material may be any copper or copper alloy known as a base material used for electronic parts such as connectors and terminals, but connection terminals of electrical and electronic equipment, etc. In view of the fact that it is used in the above, a material having a high electrical conductivity (for example, IACS (International Anneal Copper Standard: a value obtained when the conductivity of an international standard annealed copper is set to 100) is about 15 to 80%) is used. Preferably, for example, Cu-Sn-P system (for example, phosphor bronze), Cu-Zn system (for example, brass, brass), Cu-Ni-Zn system (for example, white), Cu-Ni-Si system (Corson alloy), Cu-Fe-P based alloys and the like can be mentioned. The shape of the base material is not particularly limited, but is generally provided in the form of a plate, a strip, a pressed product, and any of pre-plating and post-plating may be used.

  Moreover, as copper or copper alloy, what gave various foundation plating can also be used, for example, although it is not limited, Cu foundation plating, Ni foundation plating, Ni-Cu alloy foundation plating, Cu-Zn alloy It is possible to use copper or copper alloy that has been subjected to base plating and base plating in which Ni and Cu are sequentially laminated. In addition to ensuring heat resistance, these base platings are appropriately applied to prevent diffusion of the base material and plating components and improve conductivity, insertion / removability, and solderability. Any method known to those skilled in the art may be used for the base plating method.

2. Sn plating The copper or copper alloy according to the present invention is Sn plated. In the present invention, there are a plurality of protrusions formed by agglomeration of carbon particles on the surface of the Sn plating film applied to copper or a copper alloy. In the present invention, the aspect ratio of the protrusion is defined. The aspect ratio is the ratio of the height of the protrusion to the width of the protrusion. The height of the protrusion is (height from the top to the base material)-(average plating film thickness). It is a value measured as the distance between the intersections with the plating surface when a horizontal line is drawn when it falls from the apex by 1/2 of the protrusion height. If the aspect ratio is too low, that is, if the protrusion is flat, the insertion force is not sufficiently reduced. On the contrary, if the aspect ratio is too high, that is, the protrusion becomes sharp, the protrusion collapses when the terminal is fitted, and carbon particles are likely to fall off. Therefore, in the present invention, the average aspect ratio when observed from the cross section of the protrusion is set to 0.2 to 0.6. The average aspect ratio is preferably 0.3 to 0.5, more preferably 0.4 to 0.45.

  The carbon particles constituting the protrusions tend to have a large aspect ratio when the particle size is large, and the aspect ratio tends to be small when the particle size is small. Therefore, in order to achieve the aspect ratio specified in the present invention, the average particle size of the carbon particles used is preferably 0.03 to 1.0 μm, more preferably 0.03 to 0.5 μm. 0.05 to 0.1 μm is even more preferable.

The greater the number of protrusions present on the surface of the Sn plating film, the better the insertion / extraction properties. Specifically, when observed from the Sn plating surface, it is preferable that 10 or more of the protrusions are distributed in a 50 μm × 50 μm visual field. On the other hand, as the number of protrusions increases, the solderability tends to be adversely affected. Therefore, in order to achieve both insertion / removability and solderability, it is more preferable that 10 to 100 protrusions are distributed in a 50 μm × 50 μm visual field, and that 10 to 50 are further distributed. Is more preferable.
Here, the protrusions were observed from the surface with a SEM at a magnification of 500 times and were protrusions that could be detected by carbon mapping by AES among those that could be confirmed as protrusions. Furthermore, it is expected that the SEM observation from the Sn plating surface is difficult to focus because the plating surface is not smooth, and it is difficult to count accurately. Therefore, in the same visual field, as a result of observing by shifting the focus arbitrarily 5 times within the range where the projection can be observed, if the projection is in the range of 10 to 100 times or more, it is within the scope of the present invention. Can think.

The average particle size of the protrusions also affects the properties of the Sn plating film. When the average particle size of the protrusions becomes small, the insertion / extraction property tends to decrease. On the other hand, if it becomes a coarse protrusion, it tends to adversely affect solderability. Therefore, from the viewpoint of achieving both insertability and solderability, the average particle diameter of the protrusions is preferably 1 to 10 μm, more preferably 2 to 8 μm when observed from the Sn plating cross section. Preferably, it is still more preferable to set it as 3-6 micrometers. The height of the protrusion is preferably 5 μm or less. The average height is preferably 1.0 μm, more preferably 1.5 μm, and even more preferably 2.0 μm.
The particle diameter of the protrusions is the distance between the intersection points with the plating surface when a horizontal line is drawn when it falls from the apex by 1/2 of the protrusion height, and the average value is the average particle diameter.
The average particle diameter and height of the protrusions can be actually measured from the cross-sectional observation image.

The degree of aggregation of the carbon particles is also important for improving the insertion / extraction more effectively, and the size of the C aggregates in the protrusions needs to be a certain size. However, if the C aggregates in the protrusions are too large, the integrity with the Sn plating is lost, which may cause powder falling or deteriorate solderability and conductivity. Therefore, when the projection is observed from the cross section, the ratio of the width of the C aggregate to the width of the projection is preferably 20 to 120% or more, more preferably 30 to 100%, and more preferably 50 to 80%. % Is even more preferable.
The width of the C aggregates in the protrusion can be observed by exposing the cross section of the protrusion by FIB processing and mapping the cross section by EPMA.

  The amount of C occupying the Sn plating surface also affects the insertability and solderability. When the amount of C present on the Sn plating surface is increased, the insertion / extraction property is improved, but the solderability is liable to be adversely affected. In the present invention, from the viewpoint of achieving both removability and solderability, the area occupied by C, when observed from the Sn plating surface, is preferably 10 to 50%, and 20 to 40%. Is more preferably 25 to 35%. However, since the aspect ratio of the protrusions is optimized in the present invention, excellent insertion / removability can be obtained even if the amount of C is small, and compatibility with solderability can be achieved.

  When the surface roughness Rz of the copper or copper alloy according to the present invention having protrusions as described above is measured, it is generally 1 to 6 μm, typically 2 to 5 μm, more typically 3 to 4 μm. .

  The insertion force of the connector also depends on the Sn plating thickness, and the thinner the plating, the lower the insertion force. On the other hand, when Sn plating becomes thin, solderability etc. will worsen. Therefore, the Sn plating thickness may be adjusted in accordance with the target characteristics. However, in general, the average thickness of the Sn plating is 0.3 to 3.0 μm. If it is important to solderability, it may be 1.5 to 3.0 μm. The Sn plating thickness can be measured by observing a cross section of a portion where no protrusion is formed by SEM.

  In the present invention, Sn plating is not only Sn plating but also Sn alloy plating in which a small amount of Ag, Bi, In, Pb, Cu or the like is added as an additive element, for example, one or two or more of these in total 5 to 5 Sn alloy plating added about 1000 ppm is also included. By using Sn alloy plating, the generation of whiskers can be suppressed.

  The copper or copper alloy according to the present invention can be used as a material for various electronic components, and can be suitably used particularly as a conductive spring material that requires insertion / extraction such as terminals and connectors.

3. Production Method A basic method for producing copper or a copper alloy according to the present invention is to electroplate copper or a copper alloy using a Sn plating bath to which carbon particles are added.

  As the Sn plating bath, those known per se can be used. For example, an organic acid bath (for example, a phenol sulfonic acid bath, an alkane sulfonic acid bath and an alkanol sulfonic acid bath), a borofluoric acid bath, a halogen bath, a sulfuric acid bath. Electroplating can be performed using an acidic bath such as a pyrophosphoric acid bath or an alkaline bath such as a potassium bath or a sodium bath. The plating thickness can be changed by adjusting the current density, electrodeposition time, bath composition, and the like.

  The aspect ratio can be adjusted mainly by the particle size of the carbon particles added to the Sn plating bath, and the aspect ratio tends to decrease if the particle size of the carbon particles is reduced, and the aspect ratio tends to increase if the particle size is increased. In order to obtain a projection having an aspect ratio defined in the present invention, it is advantageous that the average particle diameter of carbon particles is 0.03 to 1.0 μm, preferably 0.05 to 0.1 μm. The form of the carbon particles may be spherical or scaly, but is preferably scaly from the viewpoint of cost. Moreover, since the particle diameter of the carbon particles to be added is relatively small, it is difficult to precipitate in the plating bath, and there is an effect of preventing clogging of the drain pipe.

  Further, since the aspect ratio is also affected by the degree of aggregation of the carbon particles, it is desirable to control the degree of aggregation of the carbon particles. When the degree of aggregation increases, the protrusions become coarse and the aspect ratio tends to increase. Conversely, if the degree of aggregation is too low, the protrusions become fine and the aspect ratio tends to be low. The degree of aggregation also affects the average particle size of the protrusions. The degree of aggregation of the carbon particles can be controlled by the type and amount of the aggregating agent added to the plating bath and the current density.

In obtaining the aspect ratio and the average particle size of the protrusions as defined in the present invention, one or more kinds are selected as an aggregating agent from aldehyde compounds such as paraaldehyde, naphthaldehyde, formaldehyde, and acetaldehyde, and Sn plating is performed. It is advantageous to add so that the concentration in the bath is 0.1 to 10 g / L, preferably 1 to 5 g / L, more preferably 2 to 4 g / L. When the addition amount decreases, the aggregation effect becomes insufficient, while when the addition amount increases, the aggregation is excessive. The aldehyde compound to be selected is preferably an aromatic aldehyde, particularly preferably paraaldehyde.
The current density during Sn plating is ^{2 to} 6 A / dm ² , preferably 3 to 5 A / dm ² , more preferably 3.5 to 4.5 A / dm ² . If the current density is too low, the carbon particles are difficult to be taken in, and the plating efficiency is lowered and the productivity is deteriorated. On the other hand, if the current density is too high, coarse protrusions are formed, resulting in plating burns, and the performance and appearance such as soldering are impaired.

The amount of C occupying the Sn plating surface can be adjusted by the amount of carbon particles added to the Sn plating bath. If the amount is reduced, the number of protrusions is reduced, and the amount of C occupying the Sn plating surface is also reduced. . If the amount added is increased, the number of protrusions increases, and the amount of C in the Sn plating surface also increases. In order to make the amount of C occupying the Sn plating surface within the above-mentioned range, 0.1 to 5 g / L, preferably 0.5 to 3 g / L, more preferably 1 to 3 g / L of carbon particles are added. Is advantageous.
Moreover, since it becomes difficult to take in in Sn plating film when the particle size of the carbon particle to be used becomes large, the addition amount of the carbon particle required in order to form a sufficient amount of protrusions increases. If the amount added is increased, carbon particles are liable to precipitate in the plating bath and clog the drainage pipe. However, in the present invention, since the carbon particles having a relatively small particle size are used, Sn plating is used. A sufficient amount of protrusions can be formed by adding a small amount of carbon particles.

  Examples of the present invention will be described below, but the present invention is not limited to the examples.

Preparation method : Zn: 30% by mass—13 copper alloy strips having a composition of the balance Cu and inevitable impurities (plate thickness 0.64 mm × width 50 mm × length 100 mm) are prepared, and plating is performed for each of the following steps. Was given.
Electrolytic degreasing: Electrolytic degreasing was performed in alkaline aqueous solution using the sample as a cathode.
-Pickling: Pickling was performed using a 10% by mass sulfuric acid aqueous solution.
Plating: stannous oxide 40 g / L, phenol sulfonic acid 270 g / L, surfactant 5 g / L, paraaldehyde and naphthaldehyde (type and amount added are listed in Table 1), scaly carbon particles (average particle size 0.05 μm is manufactured by Denki Kagaku Kogyo Co., Ltd., and others are manufactured by SEC Carbon Co., Ltd.) (Sn plating bath containing average particle diameter and addition amount are listed in Table 1), temperature 45 ° C., current Sn plating was performed under conditions of a density of 4.0 A / dm ² . The thickness of the Sn plating layer was adjusted by the electrodeposition time. The plating thickness was 1.0 ± 0.1 μm.

Evaluation Method The form and characteristics of the Sn plating material were evaluated by the following methods. The results are shown in Table 2.
(1) Aspect ratio and agglomerate width For each sample, any 10 of the protrusions formed on the surface were processed with a focused ion beam processing observation apparatus (FIB) FB-2100 manufactured by Hitachi High-Technologies Corporation, The cross section was exposed and observed by SEM. The aspect ratio (height of protrusions / width of protrusions) was calculated for each, and the average value of 10 locations was taken as the average aspect ratio of the sample. here,
Projection height: (height from top to base metal)-(average plating film thickness)
Width of protrusion: The distance between the intersections with the plating surface when a horizontal line is drawn at a point lowered from the apex by 1/2 of the protrusion height. For reference, FIGS. 1 and 2 show SEM images (magnification: 14000 times) when the cross sections of the protrusions of Example 3 and Comparative Example 4 are observed.
In accordance with the above observation, the projection cross section is mapped by EPMA, and the width of carbon detected is measured. From the width of the projection, the aggregate width (%) = the aggregate width (μm) / projection. Width (μm) × 100.
(2) Average particle size of carbon particles For each carbon particle, the particle size distribution was measured with a laser light diffusion type particle size distribution analyzer (LPA3100 manufactured by Otsuka Electronics Co., Ltd.), and the particle size of 50% cumulative distribution was taken as the average particle size. .
(3) Average particle diameter of protrusions The width of the protrusions in the aspect ratio evaluation method was defined as the particle diameter. The average of 10 locations was defined as the average particle size.
(4) Average height of protrusions It was measured by the same method as the height of protrusions in the aspect ratio evaluation method. The average of 10 locations was the average height.
(5) Amount of C in the Sn plating surface Elemental mapping of the surface by EPMA was performed for each sample. The area of the portion where carbon was detected was measured from the result of element mapping, and the proportion of the area occupied by carbon was calculated. The average value at three locations was taken as the measurement result.
(6) Sn plating thickness (average plating film thickness)
About each sample, arbitrary 10 places in which the protrusion was not formed were processed with the focused ion beam processing observation apparatus FB-2100 by Hitachi High-Technologies Corporation, the cross section was exposed, and SEM observation was carried out. Sn plating thickness was measured in the SEM image of each cross section, and the average value was made into Sn plating thickness.
(7) Insertion force After pressing each sample into the shape of a 090 type male terminal (width: 2.3 mm, thickness: 0.64 mm), using a desktop load measuring instrument 1310NR made by Aiko Engineering, a female terminal The load when fitted was measured. Female terminal: 090 type SMTS terminal manufactured by Sumitomo Wiring Systems, insertion speed: 50 mm / min, insertion distance: 5 mm
(8) Solderability The solder wetting time of each sample was measured using a Solder Checker SAT-5000 manufactured by Reska. Sample size: width 10 mm × length 20 mm, flux: 25% rosin-methanol solution, solder temperature: 250 ° C., solder composition: Sn-3.0Ag-0.5Cu (705M manufactured by Senju Metal), immersion speed: 20 mm / sec, immersion time: 10 seconds, immersion depth: 2 mm.
(9) Powder fall A cellophane adhesive tape having a width of 24 mm was attached to each sample and peeled off in a direction perpendicular to the plating surface. The peeled tape was observed and judged by the presence or absence of carbon adhesion. The case where the adhesion of carbon was confirmed on the tape surface by observation with an optical microscope (magnification 50 times, 400 times) was marked with x, and the case where it was not confirmed was marked with ◯.
(10) Surface roughness Rz
The surface shape was measured and calculated by a non-contact type three-dimensional shape measuring device NH-3 (He-Ne laser, wavelength: 633 nm, output: 1.8 mW) manufactured by Mitaka Kogyo Co., Ltd.

Examples 1-3
It is plated with an Sn plating bath containing 0.5 to 1.5 g / L of carbon particles having a particle size of 0.05 μm, and the insertion force is significantly lower than that of Comparative Example 4 in which no carbon particles were added, Solderability was good, and no powder fall was observed.

Examples 4 and 5
The carbon particles having a particle diameter of 0.5 μm are plated with an Sn plating bath to which 1.5 to 2.0 g / L is added, and the insertion force is significantly lower than that of Comparative Example 4 in which no carbon particles are added, Solderability was good, and no powder fall was observed.

Example 6
It is plated with an Sn plating bath containing 3.0 g / L of carbon particles having a particle size of 1.0 μm, and the insertion force is significantly lower than that of Comparative Example 4 in which no carbon particles are added, and the solderability is It was good and no powder fall was observed.

Example 7
In the same manner as in Examples 1 to 3, plating was performed using a Sn plating bath to which carbon particles having a particle diameter of 0.05 μm were added. Projections having an aspect ratio of 0.3 were formed, and the effect of reducing the insertion force and preventing powder falling was obtained. However, since the addition amount was as small as 0.1 g / L, the distribution of the projections was small, and no projections with a height of 2 μm or more that contributed to the reduction in insertion force were formed. It was small.

Examples 8 and 9
Like Example 4 and 5, it plated by the Sn plating bath which added the carbon particle with a particle size of 0.5 micrometer. Protrusions having an aspect ratio of 0.4 were formed, and the effect of reducing the insertion force and preventing powder falling was obtained. However, in Example 8, since the addition amount was as small as 0.5 g / L, the amount of protrusions having a height of 2 μm or more that contributed to the reduction in insertion force was small, so the reduction in insertion force was lower than in Examples 1-6. It was small. Moreover, in Example 9, since the addition amount was as large as 10 g / L, the area occupied by carbon increased, so that the solderability was inferior to Examples 1-6.

Comparative Example 1
The amount of carbon particles added is the same as in Example 2. However, since the particle diameter is as small as 0.02 μm, the aspect ratio of the projections formed is small, and the effect of reducing the insertion force cannot be obtained.

Comparative Example 2
The amount of carbon particles added is the same as in Example 1, but the particle size is as large as 5.0 μm, so the carbon particles are not efficiently taken into the Sn plating film, so the projection distribution is small and the insertion force is reduced. The insertion force did not decrease because no contributing protrusion with a height of 2 μm or more was formed.

Comparative Examples 3 and 4
Although the addition amount was adjusted, since the particle diameter of the carbon particles to be added was large, the aspect ratio of the protrusions was increased, and powder falling occurred.

Comparative Example 5
Since the amount of the flocculant added was large, the area occupied by carbon increased, the solderability was poor, the aspect ratio increased, and powder falling occurred.

Comparative Example 6
In the same manner as in Examples 1 to 3, plating was performed using a Sn plating bath to which carbon particles having a particle diameter of 0.05 μm were added. Since the amount of the flocculant added was large and the area occupied by carbon increased, the solderability was inferior to those of Examples 1-6.

Comparative Example 7
This is an example in which carbon particles are not added, and is an example that serves as a reference for insertion force and solderability.

Comparative Example 8
This is an example in which carbon particles and additives are not added, and is an example serving as a reference for insertion force and solderability.

It is a SEM image (magnification 14000 times) when the cross section of the protrusion of Example 3 is observed. It is a SEM image (magnification 14000 times) when the cross section of the protrusion of the comparative example 4 is observed.

Claims (6)

  Copper or copper alloy plated with Sn, wherein the Sn plating has a plurality of protrusions formed by agglomeration of carbon particles on the surface, and the protrusions are average aspect ratios when observed from a cross section. Or a copper alloy in which is 0.2 to 0.6.   The copper or copper alloy according to claim 1, wherein the average particle diameter of the protrusions is 1 to 10 μm when observed from the Sn plating cross section.   The copper or copper alloy according to claim 1 or 2, wherein the area occupied by C is 10 to 50% when observed from the Sn plating surface.   The copper or copper alloy according to any one of claims 1 to 3, wherein the surface roughness is 1 to 6 µm.   The electronic component provided with the copper or copper alloy as described in any one of Claims 1-4.   Sn plating bath in which 0.1 to 5 g / L of carbon particles having an average particle size of 0.03 to 1.0 μm and 0.1 to 10 mL / L of one or more aldehyde compounds are added in total. The method for manufacturing the copper or copper alloy as described in any one of Claims 1-3 including using and electroplating to copper or a copper alloy.