KR20120114341A - Copper alloy for electronic material and method of manufacture for same - Google Patents

Abstract

Provided is a copper alloy for an electronic material having excellent uniformity of a plated film.
When the cross section in the direction parallel to the rolling direction was observed by SIM, the area ratio occupied by the crystal grains having an amorphous structure and a particle diameter of less than 0.1 μm in the range of 0.5 μm or less in the depth from the surface layer was 1% or less, and the depth from the surface layer. Is 0.2? The copper alloy for electronic materials whose number ratio of the crystal grains of a particle size of 0.1 micrometer or more and less than 0.2 micrometer occupies 47.5% or more with respect to the whole crystal grain whose particle diameter is 0.1 micrometer or more in 0.5 micrometer range.

Description

Copper alloy for electronic materials and its manufacturing method {COPPER ALLOY FOR ELECTRONIC MATERIAL AND METHOD OF MANUFACTURE FOR SAME}

TECHNICAL FIELD The present invention relates to a copper alloy suitable as an electronic material requiring excellent plating property and a method of manufacturing the same.

In the copper alloy used for electronic devices, in addition to the functional material plating using the physical properties of the plating film itself such as electrical properties and magnetic properties, bonding plating for wire bonding or printed board mounting is performed. For example, Ni plating, Cu plating, Sn plating, and the like are applied to conductive spring materials such as terminals, connectors, switches, and relays for the purpose of improving contact resistance, solderability, and insertion extraction ability. Ag plating and Cu plating for bonding and solder plating for substrate mounting are performed.

In some types of copper alloys, such as a corson alloy and a phosphor bronze, when a surface is plated, a plating film may be formed nonuniformly (FIG. 2). When the surface of such a plated film is observed with a microscope of high magnification, island-like dents (hereinafter referred to as "island plating") are seen at a thin spot of the plated film (FIG. 3). If the plated film is nonuniform, there arises a problem that various functions imparted by the plated film are not sufficiently exhibited in addition to the appearance problem.

By the way, in the copper alloy manufactured generally by combining heat processing, hot rolling, cold rolling, and buff polishing after casting, there exists a layer different from the inside called a process alteration layer in a surface layer. The processing altered layer is composed of a veil ratio layer of amorphous tissue at the outermost side and a fine crystal layer at the inner side thereof. The grains gradually increase as they go inward, and eventually become the same size as the parent grains.

It is known that the processing altered layer has a bad influence on plating property conventionally, and it has been performed to remove a process altered layer before plating.

For example, in Unexamined-Japanese-Patent No. 11-29894 (patent document 1), since the processing altered layer inhibits the adhesiveness of a plating film and a base material, it is surface by the electrolytic etching process in aqueous alkali solution, such as caustic soda water. It is described that nickel plating should be performed after removing the processed altered layer (thickness of about 30 to 40 µm).

Japanese Laid-Open Patent Publication No. 2006-2233 (Patent Document 2) describes the removal of a damaged layer for the purpose of providing a plated product excellent in moldability, in which cracking does not occur in the plating layer due to bending or the like. As a method for removing the processed deteriorated layer, a dissolution method with acids such as sulfuric acid, nitric acid, hydrochloric acid, hydrogen peroxide, hydrofluoric acid, a current dissolution method in an electrolyte solution, a sputtering method, an etching method, and the like are described.

Unexamined-Japanese-Patent No. 2007-39804 (patent document 3) provides the processing altered layer of a surface layer for the purpose of providing the copper alloy for electronic devices excellent in plating property which does not produce abnormal precipitation of plating and the fall of oxide film adhesiveness. The copper alloy for electronic devices which controlled the thickness of (the amorphous-structure of less than 0.2 micrometer of grain diameters) to 0.2 micrometer or less is described. The thickness of the processing deterioration layer here measures the thickness of the position where the processing deterioration layer is the thickest in the visual field which magnified and observes, and is an average of the measured value in five observation points. It is described that the processed deformed layer is removed by a physical dissolution treatment such as chemical dissolution treatment, electrochemical dissolution treatment, sputtering, and the like. In this embodiment, immersion in a mixed acid of sulfuric acid and hydrogen peroxide solution and heating in a hydrogen reduction atmosphere are described. It is described that the processed deteriorated layer was removed by electrolytic dissolution in an aqueous solution containing heat treatment and phosphoric acid in.

Japanese Patent Application Laid-Open No. 11-29894 Japanese Patent Laid-Open No. 2006-2233 Japanese Unexamined Patent Publication No. 2007-39804

Prior art documents describe the removal of the deformed layer for the purpose of suppressing adhesion between the plated film and the base material and abnormal deposition of the plate, but there is still room for improvement in the uniformity of the plated film. Then, this invention makes it a subject to provide the copper alloy for electronic materials excellent in the uniformity of a plating film. Moreover, another object of this invention is to provide the manufacturing method of such a copper alloy for electronic materials.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, rather than removing a process alteration layer completely, the present invention removes only a veil ratio layer among the process alteration layers, and the microcrystal layer remains only a predetermined thickness, and uniformity of a plating film is carried out. I found out that this is an improvement. Specifically, it has been found that crystal grains having a particle size of 0.1 µm or more and less than 0.2 µm contribute to improving the uniformity of the plated film, and therefore it is important to leave only a predetermined thickness of a layer having a predetermined ratio or more of crystal grains having a particle diameter in this range.

The present invention completed on the basis of the above findings, in one aspect, has an amorphous structure and a particle diameter of less than 0.1 μm in a range of 0.5 μm or less when the cross section in a direction parallel to the rolling direction is observed by SIM. The area ratio occupied by the crystal grain is 1% or less, and the depth from the surface layer is 0.2? It is a copper alloy for electronic materials whose number ratio which the particle diameter occupies for the whole crystal grain whose particle diameter is 0.1 micrometer or more in 0.5 micrometer or more occupies 0.1 micrometer or more and less than 0.2 micrometer is 47.5% or more.

In one Embodiment of the copper alloy for electronic materials which concerns on this invention, when the cross section of the direction parallel to a rolling direction is observed by SIM, the whole crystal grain whose particle diameter is 0.1 micrometer or more in the range of the depth from a surface layer less than 0.2 micrometer. The proportion of particles occupied by the crystal grains having a particle diameter of 0.1 µm or more and less than 0.2 µm is 57.5% or more.

In another embodiment of the copper alloy for electronic materials according to the present invention, the copper alloy is phosphor bronze, titanium copper, or corson alloy.

In another aspect of the present invention, the surface of the copper alloy base material is # 600? When polishing was carried out with an abrasive having a number of times of 8000 and a cross section in a direction parallel to the rolling direction was observed with SIM after step 2, the depth from the surface layer was 0.2? Step 1 of forming a modified layer having a sufficient thickness such that the ratio of the number of crystal grains having a particle size of 0.1 µm or more and less than 0.2 µm to the total number of grains having a particle size of 0.1 µm or more in a range of 0.5 µm is 47.5% or more, and then, When the cross section in the direction parallel to the rolling direction was observed by SIM, the area ratio occupied by the amorphous grains and the crystal grains having a particle diameter of less than 0.1 μm in the range of 0.5 μm or less was 1% or less, and the depth from the surface layer was 0.2? In the range of 0.5 µm, 0.01 to 0.01% of the total grains have a particle size of 0.1 µm or more and less than 0.2 µm so that the proportion of the number of crystal grains is 47.5% or more. It is a manufacturing method of the copper alloy for electronic materials containing the process 2 of grind | polishing with the abrasive | polishing material which has a particle size (d50) of 0.5 micrometer, and removing an amorphous structure and a fine crystal grain whose particle diameter is less than 0.1 micrometer from a processing-deterioration layer.

In one embodiment of the method for producing a copper alloy for an electronic material according to the present invention, the abrasive used in Step 1 is made of silicon carbide, and the abrasive used in Step 2 is made of aluminum oxide or colloidal silica.

In one Embodiment of the manufacturing method of the copper alloy for electronic materials which concerns on this invention, grinding | polishing of process 1 and process 2 is performed by buffing polishing.

In yet another aspect, the present invention is a plated object in which a plated film is formed on the surface of a copper alloy according to the present invention.

In one embodiment of the plated material according to the present invention, the plated film contains any one or more of Ni, Sn, and Ag.

According to the present invention, the uniformity of the plating film applied to the copper alloy surface is improved, and island plating is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is an example of the SEM photograph of the uniform plating film | membrane performed on the copper alloy surface which concerns on this invention.
2 is an example of an SEM photograph of a non-uniform plated film applied to a copper alloy surface.
FIG. 3 is an enlarged SEM photograph of part of island-like plating in FIG. 1. FIG.
4: is a schematic diagram of the copper alloy cross section which concerns on this invention (Source: "Metal Surface Technology Handbook", Metal Surface Technology Association revised edition).

<1. Composition of Copper Alloys ＞

The present invention can be applied to copper alloys having various compositions, and is not particularly limited. However, the present invention can be preferably applied to phosphor bronze, corson alloy, brass, silver silver and titanium copper, in which island plating is a problem.

In the present invention, phosphor bronze is a copper alloy containing copper as a main component and containing Sn and P of less mass. As an example, phosphor bronze is Sn? 11 mass%, P is 0.03? It contains 0.35 mass% and has a composition which consists of remainder copper and an unavoidable impurity.

In this invention, a corson alloy means the copper alloy which Si and the element which forms a compound (for example, any 1 or more of Ni, Co, and Cr) are added, and are precipitated as a 2nd phase particle in a mother phase. As an example, Corson alloys contain Ni 1.0? 4.0 mass%, Si to 0.2? It contains 1.3 mass% and has a composition which consists of remainder copper and an unavoidable impurity. As another example, Corson alloys contain Ni 1.0? 4.0 mass%, Si to 0.2? 1.3 mass%, Cr is 0.03? It contains 0.5 mass% and has a composition which consists of remainder copper and an unavoidable impurity. As another example, Corson alloys contain Ni 1.0? 4.0 mass%, Si to 0.2? 1.3 mass%, Co is 0.5? It contains 2.5 mass% and has a composition which consists of remainder copper and an unavoidable impurity. As another example, Corson alloys contain Ni 1.0? 4.0 mass%, Si to 0.2? 1.3 mass%, Co is 0.5? 2.5 mass%, Cr to 0.03? It contains 0.5 mass% and has a composition which consists of remainder copper and an unavoidable impurity. As another example, Corson alloys contain Si? 1.3 mass%, Co is 0.5? It contains 2.5 mass% and has a composition which consists of remainder copper and an unavoidable impurity.

Other elements (for example, Mg, Sn, B, Ti, Mn, Ag, P, Zn, As, Sb, Be, Zr, Al and Fe) may optionally be added to the Corson alloy. It is common to add these other elements to about 2.0 mass% in total. For example, as another example, the Coson alloy may contain Ni 1.0 to. 4.0 mass%, Si to 0.2? 1.3 mass%, Sn is 0.01? 2.0 mass%, Zn is 0.01? It contains 2.0 mass% and has a composition which consists of remainder copper and an unavoidable impurity.

In the present invention, brass is an alloy of copper and zinc, and particularly refers to a copper alloy containing 20% by mass or more of zinc.

In the present invention, the amount refers to a copper alloy containing copper as a main component, 60% by mass to 75% by mass of copper, 8.5% by mass to 19.5% by mass of nickel, and 10% by mass to 30% by mass of zinc.

In the present invention, titanium copper is composed of copper as the main component and Ti is 1.0 mass%? It refers to the copper alloy containing 4.0 mass%. As an example, titan copper has a Ti of 1.0? It contains 4.0 mass% and has a composition which consists of remainder copper and an unavoidable impurity. As another example, titan copper may contain Ti at 1.0? 4.0 mass%, Fe is 0.01? It contains 1.0 mass% and has a composition which consists of remainder copper and an unavoidable impurity.

<2. Sectional Organization ＞

When the cross section of the direction parallel to the rolling direction of the copper alloy which concerns on this invention is observed by SIM, it has the following characteristic structure forms.

First, fine grains with an amorphous tissue and a particle diameter of less than 0.1 mu m should be removed. This is because such a structure causes "island plating" and adversely affects the uniformity of the plated film.

Specifically, the area ratio of the amorphous grains and the crystal grains having a particle size of less than 0.1 µm in the range of 0.5 µm or less in depth from the surface layer is 1% or less, preferably 0.5% or less, and more preferably 0%. The reason for the depth from the surface layer to 0.5 mu m is specified because the influence on the uniformity of the plated film is less at the deeper point. The area ratio is measured by the following method. Specifically, a measurement region of 0.5 μm in the depth direction and 15 μm in the width direction is set from the surface layer, and marking is performed on crystal grains having a particle size of 0.1 μm or more, and the marked crystal grains and other tissues, that is, amorphous tissue and particle diameter. Crystal grains of less than 0.1 mu m are binarized and discriminated by image processing. Thereby, the area ratio occupied by the amorphous structure and the crystal grain below 0.1 micrometer with respect to the whole measurement viewing area is calculated. We assume average value of 5 vision as measured value.

On the other hand, crystal grains having a particle size of 0.1 µm or more and less than 0.2 µm should be actively left because they contribute to improving the uniformity of the plated film. Although the particle diameter of the said range belongs to the crystal grain which comprises a microcrystal layer by the conventional knowledge, it was considered to remove it, but according to the research of this inventor, it is preferable to form actively in order to raise the uniformity of a plating film rather. Do. In addition, if the crystal grains of this size are removed, the remaining grains become larger grains. Such large grains also hardly contribute to the uniformity of the plating film.

Therefore, in one embodiment of the copper alloy according to the present invention, the depth from the surface layer is 0.2? In the range of 0.5 micrometer, the ratio of the number of crystal grains which occupy 0.1 micrometer or more and less than 0.2 micrometer is 50% or more with respect to the whole crystal grain whose particle size is 0.1 micrometer or more, It is preferable that this number ratio is still higher, for example, 50? It can be set to 90%. However, in order to increase the residual ratio of the crystal grains in the particle size range, the ratio of the amorphous structure and the fine grains having a particle diameter of less than 0.1 µm also gradually increases, and the effect of improving the uniformity of the plated film is reduced. Therefore, a preferable number ratio is 80% or less, More preferably, it is 70% or less.

Moreover, in another embodiment of the copper alloy which concerns on this invention, the ratio of the number which the crystal | crystallization of 0.1 micrometer or more and less than 0.2 micrometer occupies with respect to the whole crystal grain whose particle diameter is 0.1 micrometer or more in the depth from the surface layer is less than 0.2 micrometer. It is 60% or more, and it is preferable that this number ratio is still higher, for example, 60? It can be set to 90%. However, for the same reason as above, since the effect of improving the uniformity of the plated film is reduced if it is too high, the preferred number ratio is 90% or less, and more preferably 80% or less.

In the present invention, the number ratio of crystals having a particle size of 0.1 µm or more and less than 0.2 µm to the whole crystal grain having a particle size of 0.1 µm or more in each depth range is measured by the following method. First, the cross section is exposed by cutting the cross section in a direction parallel to the rolling direction of the copper alloy to be measured by FIB, and then the magnification is 8000? Simulate the cross section by 15000 times. Subsequently, the depth range of less than 0.2 micrometer from the surface layer, and 0.2-? It divides into the depth range of 0.5 micrometer, and measures the particle size of all the crystal grains which exist in a visual field one by one, and calculates the ratio of the number which the crystal | crystallization which a particle size occupies 0.1 micrometer or more and less than 0.2 micrometer occupies with respect to the whole crystal grain whose particle size is 0.1 micrometer or more. This is carried out in total for 5 fields of view. Particles that are only partially visible across the field of view do not count. We assume average value of 5 vision as measured value.

In the present invention, the grain size of each grain is defined as the average value of the longest line segment in the depth direction that can traverse the inside of the grain and the longest line segment in the direction perpendicular to the depth direction.

In addition, in this invention, the said number ratio shall carry out fractional processing of the obtained measured value, and shall display in 5% unit. For example, when a measured value is 47.5% or more and less than 52.5%, it displays as 50%. Therefore, when a lower limit is set to 50%, if a measured value is 48.2%, 50.0%, and 51.2%, all will fall in the scope of the present invention.

<3. Manufacturing method ＞

The copper alloy which concerns on this invention can be manufactured by carrying out predetermined surface treatment after manufacturing the copper alloy base material which has a desired composition by combining customary means, such as heat processing, hot rolling, and cold rolling, after casting.

Before surface treatment, it is preferable to perform degreasing and pickling for the reason which removes and removes the oil-containing contamination which adheres to the surface of a raw material. Although there is no restriction | limiting in particular as a degreasing method, The method of alkali degreasing, solvent degreasing, and electrolytic degreasing is mentioned. Although there is no restriction | limiting in particular as a method of pickling, It immerses in a pickling tank containing sulfuric acid for a fixed time.

Surface treatment is ＃ 600? Step 1 of polishing with an abrasive having a number of times of 8000, followed by 0.01? Step 2 of polishing with an abrasive having a particle size of 0.2 μm is included.

Process 1 aims at forming a processing altered layer. Although the process altered layer is formed in the process of manufacturing a copper alloy by a conventional means to some extent, it is preferable to form the process altered layer of sufficient thickness by the process 1. This is because crystal grains having a particle diameter of 0.1 m or more and less than 0.2 m exist in a sufficient depth range. The number of abrasives effective for forming the work altered layer is ＃ 600? Prescribed in JIS 6001 (1998). In the range of £ 8000 and £ 1200? The range of # 4000 is preferable and # 1500? The range of # 3000 is more preferable. Although the material of the abrasive | polishing material used at the process 1 is not limited, For example, silicon carbide, aluminum oxide, a diamond, etc. are mentioned, It will not specifically limit, if it is in the said number of times.

In the process 2, it aims at removing the outermost veil ratio layer (corresponding to microcrystalline grains whose amorphous structure and particle diameter are less than 0.1 micrometer in this invention) from the process-deteriorated layer formed in process 1. The particle size of the abrasive which is effective for selectively removing the bale ratio layer from the processed altered layer is measured by laser diffraction scattering method, and the d50 is 0.01? 0.5 micrometer, and 0.05? The range of 0.4 micrometer is preferable, and 0.1? The range of 0.3 micrometer is more preferable. At a particle size larger than 0.1 mu m, the grains are easily removed to grains having a particle diameter of 0.1 mu m or more and less than 0.2 mu m. Although it does not restrict | limit as a material of the abrasive | polishing material used at the process 2, Aluminum oxide or colloidal silica is preferable at the point which has a small particle size.

It is preferable to perform grinding | polishing of a process 1 and a process by buffing polishing. In the present invention, buff polishing refers to polishing carried out by incorporating an abrasive into a polishing cloth using a paste or suspension (slurry), regardless of whether or not the buff is rotated. In order to uniformize the distribution of crystal grains having a thickness of less than m, it is preferable to press the copper alloy substrate at a constant pressure while rotating the buff at a high speed.

Between steps 1 and 2, pickling may be performed in order to easily remove only the veil ratio layer by the second polishing. However, pickling at this point is sulfuric acid, preferably at a concentration of 10? Preference is given to using 200 g / l sulfuric acid. This is because when mixed with sulfuric acid and hydrogen peroxide, grains of 0.1 µm or more and less than 0.2 µm are easily removed.

<4. Kind of plating ＞

Various platings can be performed about the copper alloy which concerns on this invention, and there is no restriction | limiting in particular in the kind. For example, plating of Ni, Sn, Ag, etc. can be performed. Especially, since Ni plated plating is easy to form, Ni can use this invention especially suitably. Therefore, in one Embodiment of this invention, a plating film contains any 1 or more types of Ni, Sn, and Ag.

There is no restriction | limiting in particular as a plating method, For example, it can obtain by wet plating, such as electroplating and electroless plating, or dry plating, such as CVD or PVD. Electroplating is preferable from the viewpoint of productivity and cost.

<5. Uses ＞

The copper alloy related to the present invention may be provided in a variety of new products such as plate, jaw, tube, rod and wire processed form, and lead frame, connector, pin, terminal, relay, switch, It can be used suitably for electronic components, such as a secondary battery foil material.

Example

Although the Example of this invention is shown with a comparative example below, these Examples are provided in order to understand this invention and its advantage better, and it does not intend that invention is limited.

After casting the copper alloys of the compositions shown in Tables 1 and 2, heat treatment, hot rolling and cold rolling were appropriately repeated to prepare copper alloy plates having a thickness of 0.1 mm, respectively. These copper alloy plates were degreased by alkali degreasing and then pickled by immersion in an pickling bath containing 100 g / L sulfuric acid, followed by surface treatment in the order shown in Tables 1 and 2. In Table 1 and 2, in the "buffing polishing (1)", silicon carbide was used as an abrasive. "Sulfate" in "pickling" is a treatment of immersing the test plate in sulfuric acid with a concentration of 100 g / l for 10 seconds, "mixed acid" is a test plate in an aqueous solution containing 100 g / l sulfuric acid and 10 g / l hydrogen peroxide It is the process of immersion for 10 seconds. "# 3000" of "buff polishing (2)" used silicon carbide as an abrasive. The particle size (d50) of the abrasive used in the buff polishing (2) was measured using a laser diffraction type particle size distribution analyzer SALD-2100 manufactured by Shimadzu Corporation.

About the copper alloy plate after surface treatment, by the method mentioned above,

A) The area ratio of the crystal grains in the range whose depth from the surface layer is 0.5 micrometer or less, and a particle size of less than 0.1 micrometer,

B) Depth from surface layer is 0.2? The proportion of the number of crystal grains having a particle diameter of 0.1 µm or more and less than 0.2 µm to the whole crystal grain having a particle diameter of 0.1 µm or more in the range of 0.5 µm, and

C) The ratio of the number of crystal grains occupying 0.1 micrometer or more and less than 0.2 micrometer was calculated | required with respect to the whole crystal grain whose particle diameter is 0.1 micrometer or more in the range from the depth below 0.2 micrometer.

Regarding the values of B and C in the table, values obtained by fractional treatment of measured values and described in units of 5% are described. For example, 62.5% or more and less than 67.5% were described as 65%.

Thereafter, Ni plating was performed under the following conditions.

<Ni plating condition>

Bath composition: NiSO ₄ -6H ₂ O 280 g / ℓ

Plating condition: Current density: 5 A / dm ²

            Plating Time: 15 s

Then, the optical micrograph (magnification: x100, viewing area: 0.15 mm <2>) of each plating surface was image | photographed, and the area ratio of island-like plating was measured and observed. Evaluation is as follows.

S: No plating on island

A: The area ratio of island plating is 10% or less

B: 20% or less of area ratio of island plating plating exceeding 10%

C: The area ratio of island plating is over 50% and 50% or less

D: The area ratio of island-like plating exceeds 50%

The healthy part and the island plating part are binarized by an image analysis device, and the area ratio of island plating is calculated.

The results are shown in Tables 1 and 2. 1 is a SEM photograph of the plating surface of No. 14.

From Tables 1 and 2, the copper alloy No. 1? It turns out that 27 silver-plated plating is reduced and it is excellent in uniform plating property.

On the other hand, in Comparative Examples No. 28, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, and 53, since the buffing was not performed, the processing altered layer itself was not formed. Therefore, excellent plating property was not obtained.

In Comparative Examples Nos. 29, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52 and 54, although the first buffing was performed, the processed deterioration layer was formed, but it was not removed. As it was, the bale layer remained. As a result, excellent plating property was not obtained.

In Comparative Example No. 30, since the deformed layer formed by the first buffing was removed by strong pickling, not only the veil ratio layer but also the grains having a particle size of 0.1 µm or more and less than 0.2 µm were excessively removed. As a result, plating property was inferior compared with the invention example.

Comparative Example No. 31 removed the processed altered layer formed by the first buffing with strong pickling, and then performed the second buffing. Therefore, not only the Bale ratio layer but also the grains having a particle size of 0.1 µm or more and less than 0.2 µm were completely removed. It has been removed. As a result, plating property was inferior compared with the invention example.

In Comparative Example No. 32, the processed altered layer formed by the first buffing was removed by strong pickling, and the same buffing as the first was performed. As a result, the same characteristics as in Comparative Example 29 were obtained.

Claims (8)

When the cross section in the direction parallel to the rolling direction was observed by SIM, the area ratio occupied by the crystal grains having an amorphous structure and a particle diameter of less than 0.1 μm in the range of 0.5 μm or less in the depth from the surface layer was 1% or less, and the depth from the surface layer. Is 0.2? The copper alloy for electronic materials whose number ratio of the crystal grains of a particle size of 0.1 micrometer or more and less than 0.2 micrometer occupies 47.5% or more with respect to the whole crystal grain whose particle diameter is 0.1 micrometer or more in 0.5 micrometer range. The method of claim 1,
When the cross section in the direction parallel to the rolling direction was observed by SIM, the ratio of the number of crystal grains having a grain size of 0.1 µm or more and less than 0.2 µm to the whole grains having a particle size of 0.1 µm or more in the range from the surface layer of less than 0.2 µm Copper alloy for electronic materials which is 57.5% or more. The method according to claim 1 or 2,
Copper alloys are copper alloys for electronic materials, which are phosphor bronze, titanium copper or corson alloys. With respect to the surface of the copper alloy substrate,? When polishing was performed with an abrasive having a number of times of 8000, and a cross section in a direction parallel to the rolling direction was observed with SIM after step 2, the depth from the surface layer was 0.2? Step 1 of forming a modified layer having a sufficient thickness such that the ratio of the number of crystal grains having a particle size of 0.1 µm or more and less than 0.2 µm to the total number of grains having a particle size of 0.1 µm or more in a range of 0.5 µm is 47.5% or more, and then, When the cross section in the direction parallel to the rolling direction was observed by SIM, the area ratio occupied by the amorphous grains and the crystal grains having a particle diameter of less than 0.1 μm in the range of 0.5 μm or less was 1% or less, and the depth from the surface layer was 0.2? In the range of 0.5 µm, 0.01 to 0.01% of the total grains have a particle size of 0.1 µm or more and less than 0.2 µm so that the proportion of the number of crystal grains is 47.5% or more. A process for producing a copper alloy for an electronic material, comprising a step 2 of polishing with an abrasive having a particle size (d50) of 0.5 µm to remove amorphous grains and fine grains having a particle diameter of less than 0.1 µm from the processed altered layer. The method of claim 4, wherein
The abrasive used in Step 1 is made of silicon carbide, and the abrasive used in Step 2 is made of aluminum oxide or colloidal silica. The method according to claim 4 or 5,
The manufacturing method which performs grinding | polishing of a process 1 and a process by buffing polishing. The to-be-plated object which provided the plating film in the surface of the copper alloy in any one of Claims 1-3. The method of claim 7, wherein
The to-be-plated object whose plating film contains any 1 or more types of Ni, Sn, and Ag.

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