Copper alloy, electronic component comprising the same, and electronic device

Abstract

To provide a Corson alloy with reduced wear of a press die in press forming.SOLUTION: A copper alloy comprising 0.5-5.0 mass% in total of at least one of Ni and Co, and 0.1-1.2 mass% of Si, with the balance being Cu and inevitable impurities, wherein an integrated value of the normalized intensity of Cu3O- at a sputtering depth of 0.3 nm to 3.0 nm measured by TOF-SIMS analysis is 2.0 or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a copper alloy and an electronic component and an electronic device including the same. In particular, the present invention relates to a copper alloy containing Si and at least one of Ni and Co, and an electronic component and an electronic device including the same. [Background technology]

[0002] Copper alloys for electronic materials, used in various electronic components such as connectors, switches, relays, pins, terminals, and lead frames, are typically pressed into these components. In recent years, the miniaturization of electrical and electronic components has led to demand for copper alloys used in these components with good strength, electrical conductivity, and bendability. In response to this demand, demand for precipitation-strengthened copper alloys such as Corson alloy, which offer high strength and electrical conductivity, has increased, replacing conventional solid-solution-strengthened copper alloys such as phosphor bronze and brass. Corson alloy is an alloy in which intermetallic compounds such as Ni-Si, Co-Si, and Ni-Co-Si are precipitated in a Cu matrix, and it combines high strength, high electrical conductivity, and good bendability.

[0003] For example, Patent Document 1 (Japanese Patent Laid-Open Publication No. 2000-073130) discloses a copper alloy sheet in which the press-punching properties are improved by controlling the degree of integration of crystal orientation in a Cu-Ni-Si alloy sheet.

[0004] Furthermore, Patent Document 2 (JP 2004-002989 A) discloses a technique for controlling the surface roughness of the material surface in the direction perpendicular to the rolling direction, the thickness and composition of an oxide film, and the surface tension of the material surface, in order to provide a copper alloy for electronic materials that is compatible with high strength materials and low viscosity press oils and that has low die wear.

[0005] When Corson alloy is pressed, the press die is subject to severe wear. In particular, research by the present inventors has shown that the wear of the press die for Corson alloy can be about twice as great as that when phosphor bronze is used.

[0006] Wear of press dies has traditionally been thought to be correlated with the oxygen concentration near the surface of Corson alloys, and efforts have been made to improve this. For example, Patent Document 3 (JP 2004-149873 A) discloses a die-wear-resistant Corson copper alloy containing 1.0 to 4.5 mass% Ni, 0.3 to 1.5 mass% Si, and the remainder consisting of Cu and unavoidable impurities, characterized in that the oxygen concentration at the surface after removal of the rust-preventive coating layer formed as a result of rust prevention treatment is 2 atomic % or less. This invention discloses that wear of press dies can be significantly suppressed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-073130 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-002989 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-149873 Summary of the Invention [Problem to be solved by the invention]

[0008] However, further research by the inventors revealed that when the number of press cycles reaches approximately 6 million, there is no correlation between the oxygen concentration near the surface before pressing and the wear of the press die. Therefore, unless the Corson alloy is improved based on more appropriate parameters, the wear of the press die will not be sufficiently suppressed.

[0009] The present invention was completed in view of the above problems, and aims to provide, in one embodiment, a Corson alloy that reduces wear of press dies during press working. In another embodiment, the present invention aims to provide electronic components and electronic equipment that include such a copper alloy. [Means for solving the problem]

[0010] As a result of extensive research by the present inventors, it was found that the CuO - It has been found that by reducing the integral value of the standard strength, it is possible to effectively suppress the wear of the press die. The present invention has been completed based on the above findings, and is exemplified below.

[0011] [1] A copper alloy containing 0.5 to 5.0 mass% in total of one or more of Ni and Co, 0.1 to 1.2 mass% of Si, and the remainder being copper and unavoidable impurities, Cu3O at sputter depths of 0.3nm to 3.0nm measured by TOF-SIMS analysis - A copper alloy having a standard strength integral value of 2.0 or less. [2] The copper alloy according to [1], further containing one or more of Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, and B in a total amount of 0.005 to 3.0 mass %. [3] The copper alloy according to [1] or [2], wherein the integrated value is 1.8 or less. [4] The copper alloy according to any one of [1] to [3], which is a foil or plate having a thickness of 0.03 to 1.0 mm. [5] An electronic component comprising the copper alloy according to any one of [1] to [4]. [6] [5] An electronic device comprising the electronic component described in [5]. [Effects of the Invention]

[0012] According to one embodiment of the present invention, a Corson alloy that causes less wear to a press die during press working can be provided, and according to another embodiment of the present invention, electronic components and electronic equipment including such a copper alloy can be provided. [Brief explanation of the drawings]

[0013] [Figure 1]FIG. 2 is a diagram showing the shape of the tip of a punch used in a press die wear test in a reference example, a comparative example, and an example. [Figure 2] 2A and 2B are diagrams showing burrs on the copper alloy after a press die wear test of a reference example, where Fig. 2A shows the entire press-processed portion of the copper alloy, and Fig. 2B is an enlarged view of a part of the copper alloy. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, embodiments of the present invention will be described in detail with reference to the drawings. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes and improvements may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0015] (Copper alloy composition) The copper alloy according to this embodiment contains 0.5 to 5.0 mass % in total of one or more of Ni and Co, 0.1 to 1.2 mass % of Si, and the balance consisting of copper and unavoidable impurities. Preferably, the copper alloy is a rolled material.

[0016] (Ni, Co and Si content) By performing an appropriate aging treatment, Ni, Co, and Si precipitate as intermetallic compounds such as Ni-Si, Co-Si, and Ni-Co-Si. The action of these precipitates improves strength, and the precipitation reduces the amount of Ni, Co, and Si dissolved in the Cu matrix, improving electrical conductivity. However, if the total content of Ni and Co is less than 0.5% by mass or the Si content is less than 0.1% by mass, it becomes difficult to obtain a high-strength copper alloy. If the total content of Ni and Co exceeds 5.0% by mass or the Si content exceeds 1.2% by mass, it becomes difficult to manufacture the alloy due to hot-rolling cracking and other problems.

[0017] For this reason, the copper alloy according to the embodiment of the present invention contains at least one of Ni and Co in a total content of 0.5 to 5.0 mass% and at least 0.1 to 1.2 mass% of Si. The total content of at least one of Ni and Co is more preferably 0.8 mass% or more, and even more preferably 1.2 mass% or more. The total content of at least one of Ni and Co is more preferably 4.0 mass% or less, and even more preferably 3.0 mass% or less. The Si content is more preferably 0.35 mass% or more, and even more preferably 0.40 mass% or more. The Si content is preferably 0.90 mass% or less, and even more preferably 0.80 mass% or less.

[0018] (Other additive elements) The minor components Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, and B contribute to increasing strength. Furthermore, Zn is effective in improving the heat peeling resistance of Sn plating, Mg is effective in improving stress relaxation properties, and Cr and Mn are effective in improving hot workability. If the total content of Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, and B is less than 0.005 mass%, the above effects cannot be obtained, and if it exceeds 3.0 mass%, bending workability is significantly reduced. Therefore, the copper alloy according to the embodiment of the present invention preferably contains these elements in a total of 0.005 to 3.0 mass%, more preferably 0.01 to 1.0 mass%.

[0019] The remainder of the components other than those mentioned above consists of Cu and unavoidable impurities. Here, unavoidable impurities refer to impurity elements that are unavoidably mixed into the material during the manufacturing process. The concentration of each element of the unavoidable impurities can be, for example, 0.015 mass% or less, and preferably 0% (undetectable).

[0020] The composition of copper alloys can be measured by wet analysis. Ni can be determined using the copper separation dimethylglyoxime gravimetric method (JIS-H1056(2003)), and Si can be determined using the silicon dioxide gravimetric method (JIS-H1061(2006)). Other additive and impurity elements can also be determined using ICP atomic emission spectroscopy. Analysis of other additive elements is performed using an internal standard method, with Y (yttrium) as the internal standard. Elements other than Y can also be selected as the internal standard. ICP atomic emission spectroscopy is performed using an ICP atomic emission spectroscopy analyzer (ICP-OES) SPS3100 manufactured by Hitachi High-Tech Science Corporation or an equivalent device. For ICP atomic emission spectroscopy, a copper alloy sample is dissolved in a mixed acid containing hydrochloric acid and nitric acid (containing hydrochloric acid, nitric acid, and water in a volume ratio of 2:1:2) and then diluted.

[0021] The composition of the copper alloy may also be measured using X-ray fluorescence analysis. The X-ray fluorescence analyzer used may be a Simultix14 manufactured by Rigaku Corporation or an equivalent device. The analysis surface may be machined or mechanically polished so that the maximum surface roughness Rz (JIS-B0601(2013)) is 6.3 μm or less. When collecting samples for X-ray fluorescence analysis from the molten metal during melting and casting, the sample is cast into a shape of approximately 30-40 mm diameter and 50-80 mm thick, then cut into a thickness of approximately 10-20 mm, and the cut surface is used as the analysis surface. X-ray fluorescence analysis is performed in accordance with JIS-K0119(2008) using a wavelength dispersive method.

[0022] (CuO - (integral value of The copper alloy of this embodiment has CuO at a sputtering depth of 0.3 nm to 3.0 nm as measured by TOF-SIMS analysis. -The integral value of the standard strength is 2.0 or less. As will be described later, a low integral value is preferable in terms of suppressing wear of the press die, so the integral value is preferably 1.9 or less, more preferably 1.8 or less, even more preferably 1.7 or less, and even more preferably 1.6 or less. The lower limit of the integral value is not particularly limited, but can be set appropriately as needed, and can be, for example, 0.1 or more, 0.15 or more, or 0.20 or more.

[0023] While not intending to be bound by theory, it is believed that CuO at a sputtering depth of 0.3 nm to 3.0 nm measured by TOF-SIMS analysis - The reason why lowering the integral value of the standard strength can effectively suppress press die wear is presumed to be as follows: Press die wear is generally caused by abrasive wear of the press cutting edge. Abrasive wear refers to the wear phenomenon in which the surface is scraped away by foreign matter interposed between friction surfaces, and suppressing this foreign matter contributes to suppressing cutting edge wear. As a result of extensive research, the inventors have estimated that the foreign matter that causes cutting edge wear is Cu2O, among surface oxides. And, Cu3O measured by TOF-SIMS analysis - is a molecular ion characteristic of Cu2O, it was demonstrated that the wear of the press die can be suppressed by reducing the above integral value.

[0024] Cu3O at sputter depths of 0.3nm to 3.0nm measured by TOF-SIMS analysis - Specifically, the integral value of the standard strength is measured as follows. (Apparatus and measurement conditions) Equipment: ION-TOF TOF-SIMS or equivalent equipment Primary ion species: Bi3 + Voltage: 25kV Current: Adjust to about 0.45pA Frequency: 13.3kHz Measurement mode: negative (high mass resolution mode) ·Measurement area: 300μm×300μm Sputter ion species: Cs + Sputtering rate: 1.1 nm / min (SiO2 equivalent sputtering rate) Sputtering area: 500μm x 500μm Measurement ion: CuO - and Cu4 - Measurement pitch: approx. 0.03 nm

[0025] (standardization) The measurement pitch is approximately 0.035 nm and the sputter depth range is 0.3 nm to 3 nm. - " depth profile measurement was carried out and "Cu3O - " strength due to the "Cu4 - Cu3O at each sputtering depth divided by the intensity of - Calculate the standard strength of Cu4 - The intensity of "Cu4" is calculated by performing depth profile measurement and averaging the intensity in the sputtering depth range of 5 nm to 7 nm. - The intensity of Cu4 at each point in the sputtering depth range of 5nm to 7nm is - Here, "a sputter depth range of 0.3 nm to 3 nm" refers to the range from the first point where a sputter depth of 0.3 nm or more is measured to the last point where the sputter depth does not exceed 3 nm when data is collected for each measurement pitch, and "a sputter depth range of 5 nm to 7 nm" has the same meaning.

[0026] (CuO - (Calculation of the integral value of the standard strength) "CuO - " using a depth profile consisting of standard intensity and sputtering depth (nm) - The integral value of the standard intensity of Cu3O at each sputter depth was calculated. - The product of the standard intensity and the measurement pitch (nm) is calculated, and the sum is taken as Cu3O -The measurement pitch is the difference between the first point where a sputter depth of 0.3 nm or more is measured and the next point.

[0027] (Thickness) The Corson copper alloy of the present invention is preferably in the form of a foil or plate, and its thickness can typically be 0.03 mm to 1.0 mm. Furthermore, since the polishing step of the present invention causes almost no change in thickness, the above thickness range is also a suitable range for the copper alloy material to be subjected to the polishing step. Methods for measuring the thickness include a height gauge and a micrometer.

[0028] (Application) The copper alloy according to one embodiment of the present invention can be suitably used for electronic components including terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, electromagnetic shielding plates, camera components, etc. used in electronic devices.

[0029] (Manufacturing method) The method for producing a copper alloy according to one embodiment of the present invention is not particularly limited and can be appropriately set. In a typical production process for a Corson alloy, raw materials such as electrolytic copper, Ni, Co, and Si are first melted in a melting furnace to obtain a molten metal of the desired composition. This molten metal is then cast into an ingot. After that, hot rolling and cold rolling are performed to obtain a rolled material, which is then subjected to solution treatment and aging treatment in that order, and further subjected to final cold rolling and stress relief annealing to produce a copper alloy strip, copper alloy sheet, or copper foil having the desired thickness and properties. If necessary, heat treatment or plastic working can be performed between each process to improve properties, material shape, manufacturability, etc. Furthermore, as a finishing process, the copper alloy material can be subjected to chemical polishing, pickling, etc.

[0030] Cu3O at sputter depths of 0.3nm to 3.0nm measured by TOF-SIMS analysis - In order to suppress the integral value of the standard strength, for example, it is conceivable to control the concentration of hydrogen peroxide used in the above-mentioned pickling treatment. [Example]

[0031] Examples of the present invention will be described below together with comparative examples. These examples are provided for a better understanding of the present invention and its advantages, and are not intended to limit the invention.

[0032] (1. Comparison of press die wear due to differences in surface oxygen concentration) A copper alloy (copper alloy of 2.8 mass% Ni, 0.6 mass% Si, 0.5 mass% Sn, 0.4 mass% Zn, the remainder being Cu and unavoidable impurities) with a thickness of 0.06 mm was prepared as a test material (Reference Example 1, Comparative Example 1). Reference Example 1 and Comparative Example 1 had different manufacturing conditions, and therefore different oxygen concentrations on the surface. The composition of the obtained copper alloy was confirmed by X-ray fluorescence analysis. The X-ray fluorescence analyzer used was a Simultix14 manufactured by Rigaku Corporation. The analyzed surface was cut or mechanically polished so that the maximum surface roughness Rz (JIS-B0601 (2013)) was 6.3 μm or less. X-ray fluorescence analysis was performed based on JIS-K0119 (2008) and measured using a wavelength dispersive method.

[0033] Sputtering was performed on the copper alloys of Reference Example 1 and Comparative Example 1 under the following conditions, and the oxygen concentration of the sputtered surface was measured by X-ray photoelectron spectroscopy (XPS) at a sputtering depth of 6 nm based on an SiO2-equivalent sputtering rate (2.1 nm / min). Oxygen concentration measurements were performed at three points, and the average value is shown in Table 1. Here, the "sputtering depth of 6 nm" refers to the theoretical depth at which the sputtering depth is 6 nm based on the SiO2-equivalent sputtering rate (2.1 nm / min), and does not necessarily coincide with the actual depth of 6 nm from the copper alloy surface.

[0034] Equipment: ULVAC-PHI Inc. PHI 5000 Versa Probe II ·Achieved vacuum level: 8.2×10 -8 Pa Excitation source: Monochromated AlKα Output: 25.0W Detection area: 200μmΦ ·Incidence angle: 90 degrees Take-off angle: 45 degrees No neutralization gun Sputtering conditions: Ion species: Ar + Acceleration voltage: 2 kV, sweep area: 3 mm x 3 mm, rate: 2.1 nm / min (SiO2 equivalent) O1s spectrum measurement conditions: Accumulation count: 20, Pass energy: 23.50 eV, Measurement interval: 0.2 eV Spectral analysis conditions: Smoothing process: Savitzky-Golay method, smoothing score: 5 points, number of smoothings: 1 Background processing: Shirley method

[0035] Furthermore, using the copper alloys of Reference Example 1 and Comparative Example 1, TOF-SIMS analysis was carried out under the above-mentioned conditions, and CuO was measured at a sputtering depth of 0.3 nm to 3.0 nm. - The integrated value of the standard strength was measured. The results are shown in Table 1.

[0036] Next, using the copper alloys of Reference Example 1 and Comparative Example 1, a press die wear test was carried out under the following conditions. Press equipment: MXM-30 (manufactured by Yamada Dobby Co., Ltd.) Press rotation speed: 1000 SPM Number of press shots: 6 million Press die cemented carbide type: EVERLOY KD20 Punch shape: polygonal (Fig. 1) Clearance: 3 μm Lubricating oil: Yes

[0037] Next, the burr area of ​​the copper alloy was measured at the end of the press die wear test conditions, i.e., after 6 million shots. The larger the burr area, the more worn the press die was. Specifically, the burrs on the copper alloy were observed using a Keyence Corporation VHX-600 microscope (Figure 2). The pressed copper alloy part was observed in plan view using a ZS200 lens with coaxial epi-illumination at a magnification of ×200, and then the area of ​​the burr was measured from the burr surface using an image analysis particle size distribution analyzer, Mac-View. The results are shown in Table 1.

[0038] [Table 1]

[0039] As shown in Table 1, although the surface oxygen concentration of Reference Example 1 was clearly lower than that of Comparative Example 1, the burr area of ​​the copper alloy was actually slightly higher than that of Comparative Example 1. This is presumably because Reference Example 1 had a larger integrated value than Comparative Example 1.

[0040] (2.CuO - Comparison of press die wear due to differences in the integral value of standard strength Next, as the copper alloy of Example 1, a sample was prepared by changing the concentration of hydrogen peroxide in the pickling treatment for a copper alloy having the same composition as that of Comparative Example 1. Specifically, the concentration of hydrogen peroxide in Example 1 was 0.4 vol%, while that in Comparative Example 1 was 0.5 vol%. The composition was analyzed in the same manner as in Comparative Example 1, and the thickness of the copper alloy in Example 1 was also set to 0.06 mm.

[0041] For Example 1, TOF-SIMS analysis was carried out under the same conditions as in Comparative Example 1. - The integrated value of the standard strength was measured. In addition, a press die wear test was carried out under the same conditions as in Comparative Example 1, and the burr area of ​​the copper alloy after 6 million shots was measured. The measurement results are shown in Table 2.

[0042] [Table 2]

[0043] As can be seen from Table 2, the burr area in Comparative Example 1 is 48631.49 μm 2 Whereas the burr area in Example 1 is 39691.09 μm 2 This is because the amount of CuO in the sputtering depth of 0.3 nm to 3.0 nm measured by TOF-SIMS analysis in Example 1 was - This is thought to be due to the integral value of the standard strength being 2.0 or less.

Claims

1. A copper alloy containing 0.5 to 5.0 mass% in total of one or more of Ni and Co, 0.1 to 1.2 mass% of Si, and the balance being copper and unavoidable impurities, Cu at sputter depths of 0.3 nm to 3.0 nm measured by TOF-SIMS analysis 3 O - A copper alloy having an integral value of standard strength of 2.0 or less.

2. The copper alloy according to claim 1, further containing 0.005 to 3.0 mass% in total of one or more of Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, and B.

3. The copper alloy according to claim 1 or 2, wherein the integral value is 1.8 or less.

4. The copper alloy according to claim 1 or 2, which is in the form of a foil or plate having a thickness of 0.03 to 1.0 mm.

5. An electronic component comprising the copper alloy according to claim 1 or 2.

6. An electronic device comprising the electronic component according to claim 5.

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