Copper alloy and electronic component

Abstract

The present invention is a copper alloy containing 1.5-4.6 mass% of Ni, 0.10-0.80 mass% of Co, and 0.10-1.3 mass% of Si, with the remainder being Cu and inevitable impurities, wherein the ratio (1(200) / I0(200)) of the integrated intensity I(200) of the peak of the (200) plane obtained by X-ray diffraction measurement of the surface of the copper alloy to the integrated intensity I0(200) of the peak of the (200) plane obtained by X-ray diffraction measurement of a pure copper standard powder is 3.0-10.0, and the tensile strength in a direction parallel to the rolling direction is 850 MPa or more.

Description

Copper alloys and electronic components

[0001] This specification describes copper alloys and electronic components.

[0002] Copper alloys in which intermetallic compounds such as Ni-Si, Co-Si, and Ni-Co-Si are deposited in a Cu matrix may be called Corson alloys. Because Corson alloys have high strength and conductivity, they are sometimes used in copper alloy components of electronic parts, such as lead frames of semiconductor packages and various connection terminals. Technologies related to this type of copper alloy are described in, for example, Patent Documents 1 to 6.

[0003] Patent Document 1 aims to "provide a copper alloy sheet material for electrical and electronic components such as connectors and a method for manufacturing the same, which can simultaneously satisfy the high strength, high conductivity, and low Young's modulus required for materials for electrical and electronic components such as connectors due to the development of the electronics industry," and describes "a copper alloy sheet material for electrical and electronic components characterized by having an alloy composition containing 0.5 to 5.0 mass% of either Ni or Co or the total of both, 0.2 to 1.5 mass% of Si, with the remainder being Cu and unavoidable impurities, a 0.2% yield strength in the rolling direction of 500 MPa or more, an conductivity of 30% IACS or more, a Young's modulus of 110 GPa or less, and a bending deflection coefficient of 105 GPa or less."

[0004] Patent Document 2 describes a copper alloy sheet material suitable for lead frames, connectors, terminal materials for electrical and electronic equipment, and connectors, terminal materials, relays, switches, etc. for automotive use, which has excellent bendability, excellent strength, and low anisotropy between the rolling parallel direction and the rolling perpendicular direction of each characteristic. The material has a composition consisting of 1.0% to 5.0% by mass of Ni and 0.1% to 2.0% by mass of Si, with the remainder being copper and unavoidable impurities. In crystal orientation analysis by electron backscatter diffraction, the area ratio of crystal grains having an orientation that is within 15° of the cube orientation {001}<100> is 5% to 50%, and 40 to 100 crystal grains having an orientation that is within 15° of the cube orientation {001}<100> are dispersed within a 60 μm square area.

[0005] Patent Document 3 describes a Corson alloy and a method for producing the same, with the objective being "to provide a Corson alloy that has excellent bendability and a high Young's modulus in the direction perpendicular to the rolling direction," and states that "the Corson alloy is a rolled material containing 0.8 to 5.0 mass% of one or more of Ni and Co, 0.2 to 1.5 mass% of Si, with the remainder being copper and unavoidable impurities, wherein the area ratio of the Cube orientation {001}<100> on the surface of the rolled material is 5 to 80%, and in a cross section with a depth of 45 to 55% of the plate thickness, the area ratio of crystals oriented in the <100> direction in the width direction (TD) of the rolled material is 50% or less."

[0006] Patent Document 4 states that "there is a need for a copper alloy sheet material that has good conductivity, high yield strength, and a controlled Young's modulus," and proposes "a copper alloy sheet material characterized by having a composition in which one or two of Ni and Co are combined in a total of 1.80 to 8.00 mass%, Si is 0.40 to 2.00 mass%, and the remainder is copper and unavoidable impurities, the major axis of the crystal grains of the matrix phase is 12 μm or less, the orientation density in the {110}<001> direction is 4 or more, and the orientation density in the {110}<112> direction is 10 or more."

[0007] Patent Document 5 states, "To provide a Corson alloy having excellent bending workability and a high Young's modulus in the rolling cross direction, and a method for producing the same." and describes "a rolled material containing one or more of Ni and Co in a content of 0.8 to 5.0% by mass, Si in a content of 0.2 to 1.5% by mass, with the balance being copper and unavoidable impurities, and on the surface of the rolled material, I (200) / I 0(200) ≥1.0, and in a cross section with a depth of 45 to 55% of the plate thickness, I (220) / I 0(220) +I (311) / I 0(311) ≥1.0 [where I (hkl) and I 0(hkl) are the diffraction integrated intensities of the (hkl) plane determined by X-ray diffraction for the rolled material and the copper powder, respectively.]" has been proposed.

[0008] Patent Document 6 aims to "provide a Corson alloy that has excellent bending workability and high dimensional accuracy after press working." and describes "a rolled material containing Ni in a content of 0 to 5.0% by mass or Co in a content of 0 to 2.5% by mass, with the total amount of Ni + Co being 0.2 to 5% by mass, Si in a content of 0.2 to 1.5% by mass, with the balance being copper and unavoidable impurities, and on the surface of the rolled material, 1.0 ≤ I (200) / I 0(200) ≤5.0, in the EBSD measurement of the rolling parallel cross section, the area ratio of the Cube orientation {100}<001> is 2 to 10%, and (the average crystal grain size of the Cube orientation {100}<001> in the rolling parallel cross section) / (the average crystal grain size of the rolling parallel cross section) is 0.75 to 1.5, a copper alloy bar" is disclosed.

[0009] International Publication No. 2011 / 068134, International Publication No. 2012 / 150702, Japanese Patent Application Laid-Open No. 2014-019880, International Publication No. 2015 / 099097, Japanese Patent Application Laid-Open No. 2016-084542, Japanese Patent Application Laid-Open No. 2018-159103

[0010] In recent years, with the high functionality of electronic devices, in order to increase the number of signals in the connection terminals used therein, an increase in the number of pins and thinning of the pins of the connection terminals have been demanded. Even for thin pins, a high-strength material is required to suppress deformation.

[0011] On the other hand, in order to suppress the increase in reaction force during terminal connection due to the increase in the number of pins, the material used is required to have a low Young's modulus. Even if the dimensional accuracy of the pins of the connection terminal is low, if the material has a low Young's modulus, the impact on the variation in contact pressure during connection will be small. For this reason, a low Young's modulus of the material is also required from the standpoint of improving reliability.

[0012] This specification provides a copper alloy and electronic components that have a relatively high strength and a relatively low Young's modulus.

[0013] The copper alloy described in this specification contains 1.5% by mass or more and 4.6% by mass or less of Ni, 0.10% by mass or more and 0.80% by mass or less of Co, and 0.10% by mass or more and 1.3% by mass or less of Si, with the remainder being Cu and unavoidable impurities, and the ratio (I(200) / I0(200)) of the integrated intensity I(200) of the peak of the (200) plane obtained by X-ray diffraction measurement on the surface of the copper alloy to the integrated intensity I(200) of the peak of the (200) plane obtained by X-ray diffraction measurement on the surface of the copper alloy (I(200) / I0(200)) is 3.0 or more and 10.0 or less, and the tensile strength in the direction parallel to the rolling direction is 850 MPa or more.

[0014] The electronic components described in this specification include the above-mentioned copper alloy.

[0015] The copper alloys described above possess a relatively high strength and a relatively low Young's modulus.

[0016] This graph shows an example of the relationship between the parameter X of a semi-finished product after solution treatment and the degree of orientation of the copper alloy.

[0017] The embodiments of the copper alloy and electronic components described above will be explained in detail below. One embodiment of the copper alloy contains 1.5% by mass or more and 4.6% by mass or less of Ni, 0.10% by mass or more and 0.80% by mass or less of Co, and 0.10% by mass or more and 1.3% by mass or less of Si, with the remainder being Cu and unavoidable impurities.

[0018] When X-ray diffraction measurements are performed on the surface of this copper alloy, the ratio (I(200) / I0(200)) of the integrated intensity I(200) of the peak of the (200) plane obtained by the X-ray diffraction measurement to the integrated intensity I0(200) of the peak of the (200) plane obtained by the X-ray diffraction measurement of pure copper standard powder is 3.0 or greater and 10.0 or less. If I(200) / I0(200) is within this range, it can be said that the Young's modulus is relatively low. Furthermore, the above copper alloy has a tensile strength of 850 MPa or more in the direction parallel to the rolling direction, indicating high strength.

[0019] (Composition) The Ni content of the copper alloy is 1.5% by mass or more and 4.6% by mass or less, preferably 2.0% by mass or more and 4.6% by mass or less, more preferably 2.3% by mass or more and 4.6% by mass or less, and even more preferably 3.0% by mass or more and 4.3% by mass or less.

[0020] Furthermore, the Co content of the copper alloy is 0.10% by mass or more and 0.80% by mass or less, preferably 0.13% by mass or more and 0.60% by mass or less, and more preferably 0.18% by mass or more and 0.50% by mass or less.

[0021] If the Ni content is less than 1.5 mass%, the desired strength cannot be obtained. If the Co content is less than 0.10 mass%, the desired strength and conductivity cannot be obtained. If the Ni content exceeds 4.6 mass%, or the Co content exceeds 0.80 mass%, even if high strength is obtained, it will lead to a decrease in conductivity.

[0022] Based on the above, the total content of Ni and Co is 1.60% by mass or more and 5.40% by mass or less. In order to obtain the desired strength and conductivity, the total content of Ni and Co may be 2.50% by mass or more and 4.50% by mass or less, or 3.50% by mass or more and 4.00% by mass or less.

[0023] The Si content of the copper alloy is 0.10% by mass or more and 1.3% by mass or less, preferably 0.30% by mass or more and 1.3% by mass or less, more preferably 0.60% by mass or more and 1.3% by mass or less, and even more preferably 0.60% by mass or more and 1.0% by mass or less.

[0024] Ni-Co-Si precipitates formed by Ni, Co, and Si in copper alloys are considered to be mainly (Ni + Co)Si intermetallic compounds. However, not all Ni, Co, and Si in copper alloys become precipitates during the manufacturing of the copper alloy; some may exist in a solid solution state in the Cu matrix. While solid solution-state Ni, Co, and Si can slightly improve the strength of the copper alloy, the effect is smaller compared to the precipitated state, and they can also be a factor in reducing conductivity. Therefore, it is preferable to bring the ratio of Ni, Co, and Si content close to the composition ratio of (Ni + Co)Si. Specifically, the ratio of the total mass of Ni and Co to the mass of Si is preferably 3.4 to 5.4, and more preferably 3.8 to 5.0. In this disclosure, "A to B" means "greater than or equal to A and less than or equal to B". Here, A and B represent numerical values.

[0025] Copper alloys may also contain one or more elements selected from the group consisting of Mg, Fe, P, Cr, Ag, Zn, Sn, Pb, Zr, Al, As, Se, Te, Sb, Bi, Au, Ti, Nb, V, Ta, W, Mo, and Mn, in a total amount of 0.010% to 5.0% by mass. Typically, copper alloys may contain Cr in an amount of 0.010% to 0.50% by mass. This can further improve the strength, heat resistance, stress relaxation resistance, etc., of the copper alloy while suppressing a decrease in conductivity. The total amount of the above elements is preferably 0.030 to 3.0% by mass, and more preferably 0.050 to 1.0% by mass.

[0026] The remainder of the copper alloy, other than the elements mentioned above, consists of Cu and unavoidable impurities. Unavoidable impurities refer to impurity elements that cannot be avoided during manufacturing. The concentration of each element of unavoidable impurities can be below a detection limit, such as 0.015 mass%, and preferably 0% (undetectable).

[0027] When measuring the composition of copper alloys, the Ni content is measured using the copper-separated dimethylglyoxime gravimetric method (JIS H1056:2003), and the Si content is measured using the silicon dioxide gravimetric method (JIS H1061:2006). For the measurement of other elements and impurity elements, ICP emission spectrometry can be used. Analysis of other elements is performed according to the internal standard method, using Y (yttrium) as the internal standard. Elements other than Y can be selected as the internal standard. For ICP emission spectrometry, an ICP emission spectrometer (ICP-OES) SPS3100 manufactured by Hitachi High-Tech Science Corporation or an equivalent instrument is used. The copper alloy sample is dissolved in a mixed acid containing hydrochloric acid and nitric acid (hydrochloric acid, nitric acid, and water in a volume ratio of 2:1:2), and the resulting solution is diluted before use. Alternatively, the composition of the copper alloy may be measured using X-ray fluorescence analysis. For the X-ray fluorescence analysis, a Simultix 14 manufactured by Rigaku Corporation or a substantially equivalent instrument can be used. Here, the surface of the copper alloy can be prepared for analysis by cutting or mechanical polishing so that the maximum surface roughness Rz (JIS B0601:2013) is 6.3 μm or less. When taking a sample for X-ray fluorescence analysis from molten metal during melting and casting, the metal is cast into a shape of approximately 30-40 mm in diameter and 50-80 mm in thickness, then cut to 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 and measured using the wavelength dispersion method.

[0028] (XRD Integrated Intensity Ratio) The integrated intensity I(200) of the peak of the (200) plane obtained when measuring the surface of a copper alloy by X-ray diffraction (XRD) is such that the ratio (I(200) / I0(200)) to the integrated intensity I0(200) of the peak of the (200) plane obtained when measuring the standard pure copper powder by X-ray diffraction is 3.0 or greater and 10.0 or less. This indicates that the proportion of crystal grains oriented in the low Young's modulus cube orientation {001}<100> is large, and therefore it can be said that it is a copper alloy with a low Young's modulus.

[0029] If I(200) / I0(200) is less than 3.0, the proportion of crystal grains oriented in the cube orientation {001}<100> decreases, resulting in a higher Young's modulus. From this viewpoint, it is preferable that I(200) / I0(200) be 3.1 or higher. On the other hand, if I(200) / I0(200) exceeds 10.0, the Young's modulus becomes too low, resulting in a small contact pressure when used as a pin for sockets, etc. From this viewpoint, it is preferable that I(200) / I0(200) be 8.1 or lower. It is preferable that I(200) / I0(200) be 3.1 or higher and 8.1 or lower.

[0030] I(200) / I0(200) is determined as follows: X-ray diffraction is performed on the surface of the copper alloy, and the integrated intensity I(200) of the peak in the (200) plane is calculated from the resulting X-ray diffraction profile. Similarly, under the same conditions, X-ray diffraction is performed on a tablet-shaped pure copper standard powder, and the integrated intensity I0(200) of the peak in the (200) plane is calculated from the resulting X-ray diffraction profile. The pure copper standard powder is copper (powder, 2N5, Cat. No. 07439-08, Grade 1, purity over 99.5%, particle size 325 mesh pass) manufactured by Kanto Chemical Co., Ltd., and pressed at 400 kgf / cm². 2The material is processed into a tablet shape by pressing it with the specified pressure. By dividing the integrated intensity I(200) of the surface of the copper alloy by the integrated intensity I0(200) of the pure copper standard powder, I(200) / I0(200) can be determined. The X-ray diffraction measurement conditions are as follows. • Incident X-ray source: CoKα (1.789 Å) • Goniometer length: 300 mm • Optical system: Focused method • Incident solar slit: 2.5° • Incident slit: 1 / 2° • Longitudinal limiting slit: 10 mm • Attachment: ASC-48 • Receiving slit 1: 20 mm • Receiving solar slit: 2.5° • Receiving slit 2: OPEN • Attenuator: OPEN • Detector: 1D detector D / teX Ultra 250 (1D mode) • Monochromatization: Multilayer mirror • Kβ filter: 1D filter for Co (Fe 0.019 mm) • Tube voltage: 40 kV • Tube current: 25 mA • Scan axis: 2θ-θ • Scanning mode: FT scan • Counting time: 0.12 seconds • Counting speed: 10° / min • Sampling step: 0.02°・γ fluctuation: present ・Fitting range: same range as measurement range ・Smoothing: Savitzky-Golay smoothing (number of smoothing points: 5 points) ・Background type: B-spline ・Peak shape used for fitting: segmented pseudo-Voigt function As the X-ray diffractometer, a SmartLab manufactured by Rigaku Corporation or a substantially equivalent device can be used.

[0031] (Young's Modulus) The Young's modulus of the copper alloy in the direction parallel to the rolling direction is preferably 120 GPa or less, and more preferably 106 GPa or less. If the copper alloy is used for connection terminals such as CPU sockets, even if the connection terminal has a large number of pins to increase the number of signals, the reaction force when mounting the CPU can be reduced. Furthermore, even if there is variation in the dimensions of the pins, the variation in contact pressure can be suppressed, improving reliability. The lower limit of the Young's modulus in the direction parallel to the rolling direction is not particularly limited, but it may be, for example, 90 GPa or more, or 100 GPa or more. The copper alloy of the embodiment described here is suitably used for the above-mentioned CPU sockets and other various connection terminals, as well as lead frames of semiconductor packages. Such electronic components include this copper alloy.

[0032] To measure the Young's modulus of a copper alloy, a No. 13B test specimen, as specified in JIS Z2201:1998, is taken from the copper alloy, and a tensile test is performed on it in a direction parallel to the rolling direction. The Young's modulus can be calculated from the slope of the stress-strain curve obtained from this tensile test. Here, the stress at each measurement point of the stress-strain curve is the nominal stress σ, and the strain is the nominal strain ε. More specifically, first, the slope m of the stress-strain curve between ε 0 and 0.0012 is calculated by the least squares method. Next, when ε is 0, let σ be σ0, then ε' = ε + σ0 / m, and a new stress-strain curve representing the relationship between σ and ε' is considered instead of the original stress-strain curve representing the relationship between σ and ε. However, in this new stress-strain curve, when ε' = 0, σ = 0. The slope m′ of a new stress-strain curve between ε′ and 0.005 is calculated using the least squares method and defined as Young's modulus.

[0033] (Tensile Strength) The copper alloy has a tensile strength of 850 MPa or more in the direction parallel to the rolling direction, preferably 900 MPa or more, and more preferably 921 MPa or more. With such high strength, deformation is effectively suppressed even in thin-walled pins of connecting terminals. The tensile strength of the copper alloy in the direction parallel to the rolling direction is not limited to this, but may be, for example, 1130 MPa or less, typically 1060 MPa or less.

[0034] Tensile strength is measured in accordance with JIS Z2241:2011, in a direction parallel to the rolling direction. Specifically, a JIS 13B test specimen is taken from the copper alloy using a press so that the tensile direction is parallel to the rolling direction. The conditions for the tensile test are a specimen width of 12.5 mm, a measurement temperature of room temperature (15-35°C), a tensile speed (crosshead displacement rate) of 5 mm / min, and a gauge length of 50 mm. Two test specimens are tested, and the average of the two measured values ​​obtained from each specimen is taken as the tensile strength.

[0035] (0.2% proof stress) The 0.2% proof stress of the copper alloy in the direction parallel to the rolling direction may be 850 MPa or more, may be 900 MPa or more, or may be 925 MPa or more. If it has such high strength, even for the thin pins of the connection terminals, their deformation can be effectively suppressed. Note that the upper limit value of the 0.2% proof stress of the copper alloy in the direction parallel to the rolling direction is not particularly limited. For example, it may be 1100 MPa or less, may be 1050 MPa or less, may be 1000 MPa or less, or may be 960 MPa or less.

[0036] The 0.2% proof stress of the copper alloy is measured in the direction parallel to the rolling direction by a tensile testing machine in accordance with JIS Z2241:2011 (offset method, 0.2%). Specifically, test pieces are prepared in the same manner as the above-mentioned tensile strength. Also, the test is conducted under the same conditions as the above-mentioned tensile strength.

[0037] (Electrical conductivity) The electrical conductivity of the copper alloy in the direction parallel to the rolling direction is preferably 35.0% IACS or more, and more preferably 37.6% IACS or more. Thereby, the copper alloy can be favorably used for electronic components. Note that the electrical conductivity of the copper alloy in the direction parallel to the rolling direction may be, for example, 55.0% IACS or less, typically 50.0% IACS or less.

[0038] The electrical conductivity is measured by the four-terminal method in accordance with JIS H0505 (1975). A double bridge is used for the measurement, and the resistance measurement can be performed based on the average cross-sectional area method. The electrical conductivity can be measured at room temperature (25°C) in the direction parallel to the rolling direction. Note that the gauge length (distance between electrical resistance measurements) can be measured at 50 mm.

[0039] (Elongation at break) The elongation at break of the copper alloy is measured in the direction parallel to the rolling direction using a tensile testing machine in accordance with JIS Z2241:2011. Specifically, test pieces are prepared in the same manner as the above-mentioned tensile strength. Also, the test is conducted under the same conditions as the above-mentioned tensile strength. The measurement method of the elongation at break is obtained by the following formula. The definitions of the final gauge length and the original gauge length are the same as those in JIS Z2241:2011. Elongation at break (%) = (Final gauge length - Original gauge length) ÷ Original gauge length

[0040] (Shape) The shape of the copper alloy can be strip-shaped or plate-shaped, including sheet-shaped. Copper alloys include copper alloy strips and copper alloy plates. When the thickness of the copper alloy plate is thin (for example, less than 0.10 mm), it may be called a copper alloy foil.

[0041] The thickness of the copper alloy is, for example, 0.03 mm to 1.2 mm, typically 0.03 mm to 0.60 mm, and more typically may be 0.08 mm to 0.30 mm. The thickness of the copper alloy is measured using a micrometer in accordance with JIS B7502. As the micrometer, BMS-25MX manufactured by Mitutoyo Corporation or an equivalent device is used.

[0042] (Manufacturing method) The method for manufacturing the above-described copper alloy may include, for example, melting and casting, hot rolling, heat treatment, intermediate cold rolling, solution treatment, aging treatment, and final cold rolling in this order.

[0043] In melting and casting, the raw materials are melted and an ingot made of a copper alloy containing 1.5% to 4.6% by mass of Ni, 0.10% to 0.80% by mass of Co, 0.10% to 1.3% by mass of Si, with the balance being Cu and unavoidable impurities is cast. Then, after optionally performing homogenization annealing on this ingot, it is processed into a plate shape by hot rolling, and if necessary, further cold rolling is performed to obtain a predetermined thickness.

[0044] Subsequently, in order to control the degree of crystal orientation (I(200) / I0(200)) of the final copper alloy produced, as described above, it is important to include heat treatment, cold rolling (intermediate cold rolling), and solution treatment in that order. One of the recrystallized textures of copper and copper alloys is the Cube orientation {001}<100>. By sufficiently heating during the solution treatment to promote recrystallization and subsequent grain growth, the Cube orientation can be developed, and the degree of crystal orientation (I(200) / I0(200)) of the final copper alloy produced can be increased. Specifically, the parameter X described later for the semi-finished product obtained after the solution treatment (typically a strip material after solution treatment during the manufacturing process) is adjusted to a predetermined value. Furthermore, in order to develop the Cube orientation, it is important to introduce strain by performing cold rolling immediately before the solution treatment. Furthermore, by performing heat treatment before cold rolling, the degree of development of the cube orientation can be controlled, and the parameter X, described later, can be adjusted to a predetermined value. If necessary, heat treatment and cold rolling may be repeated before solution treatment.

[0045] The parameter X mentioned above is specifically given by the equation: X = (EL) 2 This value is expressed as × (EC). Here, EL represents the elongation at break of the semi-finished product obtained by solution treatment (unit: %), and EC represents the conductivity of the semi-finished product (unit: %IACS). The elongation at break of the semi-finished product is measured using a tensile testing machine in accordance with JIS Z2241:2011 in a direction parallel to the rolling direction of the copper alloy sheet. The conductivity of the semi-finished product is measured according to the same method as described above for the copper alloy that will be ultimately manufactured.

[0046] It has been newly discovered that there is a certain degree of correlation between the parameter X of the semi-finished product and the I(200) / I0(200) of the final copper alloy, as illustrated in Figure 1. Based on this finding, it is preferable to set the solution treatment conditions so that the parameter X of the semi-finished product is 5629 or less. This makes it easier to control the I(200) / I0(200) of the copper alloy to 3.0 or higher. Parameter X is more preferably 1000 or more and 4000 or less. If parameter X is too small, there is a risk of excessive solution treatment, which may result in a lower tensile strength of the copper alloy.

[0047] If heat treatment is performed before cold rolling, the heat treatment conditions can be 400°C to 800°C for 1 second to 25 hours. The degree of processing of cold rolling before solution treatment can be 10% to 95%. Each condition can be set as appropriate so that X is a predetermined value. The degree of processing (%) is expressed as follows: Degree of processing (%) = [(TB - TA) / TB] × 100, where TB is the thickness of the workpiece before rolling and TA is the thickness of the workpiece after rolling.

[0048] In the solution treatment, heating can be performed at a temperature of preferably 800°C to 1000°C, more preferably 850°C to 975°C, for, for example, 1 second to 60 seconds, preferably 5 seconds to 30 seconds. By increasing the heating temperature in the solution treatment, the above parameter X tends to decrease. This is thought to be because a higher heating temperature in the solution treatment increases the amount of impurity elements that solid-solve in the matrix phase, thus reducing the conductivity.

[0049] In aging treatment, heating can be performed at a temperature of, for example, 375°C to 625°C, typically 400°C to 550°C, for 1 to 50 hours, typically 1.5 to 25 hours, but is not limited to these conditions. By performing aging treatment at an appropriate temperature and time, Ni-Co-Si compounds can be sufficiently precipitated, and the coarsening and re-solubilization of precipitates can be suppressed, potentially greatly improving strength and conductivity. In order to suppress the formation of unintended oxide films, it is preferable to perform the aging treatment in an inert atmosphere such as Ar, N2, or H2.

[0050] In the final cold rolling, rolling is performed in one or more passes, sometimes divided into multiple passes. The degree of reduction in the final cold rolling is preferably 40% or more. This adds processing strain to the material, increasing its strength. On the other hand, to suppress the decrease in conductivity due to processing strain from heavy processing, the degree of reduction is preferably 90% or less. After the final cold rolling, stress-relieving annealing may be performed, for example, by holding the material at 300°C to 550°C for 5 to 900 seconds in air or an inert atmosphere such as nitrogen or argon gas.

[0051] Furthermore, in the manufacturing method described above, after each rolling and heat treatment including solution treatment and aging treatment, pickling, polishing, degreasing, surface grinding, and trimming may be performed as needed. In addition, other rolling and heat treatments may be performed at appropriate times in addition to the rolling and heat treatments described above.

[0052] The embodiments described above include the copper alloys described in (1) to (12) below and the electronic components described in (13) below. (1) A copper alloy containing 1.5% by mass or more and 4.6% by mass or less of Ni, 0.10% by mass or more and 0.80% by mass or less of Co, 0.10% by mass or more and 1.3% by mass or less of Si, with the remainder being Cu and unavoidable impurities, wherein the ratio (I(200) / I0(200)) of the integrated intensity I(200) of the peak of the (200) plane obtained by X-ray diffraction measurement on the surface of the copper alloy to the integrated intensity I(200) of the peak of the (200) plane obtained by X-ray diffraction measurement on a standard pure copper powder is 3.0 or more and 10.0 or less, and the tensile strength in the direction parallel to the rolling direction is 850 MPa or more. (2) The copper alloy according to (1) above, further containing a total of 0.010% by mass or more and 5.0% by mass or less of one or more elements selected from the group consisting of Mg, Fe, P, Cr, Ag, Zn, Sn, Pb, Zr, Al, As, Se, Te, Sb, Bi, Au, Ti, Nb, V, Ta, W, Mo, and Mn. (3) The copper alloy according to (1) or (2), further containing 0.010% by mass or more and 0.50% by mass or less of Cr. (4) The copper alloy according to any one of (1) to (3), wherein the I(200) / I0(200) ratio is 8.1 or less. (5) The copper alloy according to any one of (1) to (4), wherein the I(200) / I0(200) ratio is 3.1 or more. (6) A copper alloy according to any of (1) to (5), wherein the tensile strength in the direction parallel to the rolling direction is 900 MPa or more. (7) A copper alloy according to any of (1) to (6), wherein the tensile strength in the direction parallel to the rolling direction is 921 MPa or more. (8) A copper alloy according to any of (1) to (7), wherein the electrical conductivity in the direction parallel to the rolling direction is 35.0% IACS or more. (9) A copper alloy according to any of (1) to (8), wherein the electrical conductivity in the direction parallel to the rolling direction is 37.6% IACS or more. (10) A copper alloy according to any of (1) to (9), wherein the Young's modulus in the direction parallel to the rolling direction is 120 GPa or less. (11) A copper alloy according to any of (1) to (10), wherein the Young's modulus in the direction parallel to the rolling direction is 106 GPa or less.(12) A copper alloy according to any of (1) to (11), wherein the Young's modulus in a direction parallel to the rolling direction is 90 GPa or more. (13) An electronic component comprising a copper alloy according to any of (1) to (12).

[0053] Next, we fabricated the aforementioned copper alloy and confirmed its effects, which are described below. However, this explanation is for illustrative purposes only and is not intended to be limiting.

[0054] Using electrolytic copper as the raw material, an ingot with the composition shown in Table 1 was cast by melting it in an atmospheric melting furnace. This ingot was then subjected to homogenization annealing at 980°C for 25 minutes, followed by hot rolling to a plate thickness of 10 mm, and then surface machining. Next, after the aforementioned heat treatment and intermediate cold rolling, solution treatment, aging treatment, final cold rolling, and stress-relieving annealing were sequentially performed under the conditions shown in Table 1. This yielded a copper alloy plate (plate-shaped copper alloy). For the semi-finished product after solution treatment but before aging treatment, the elongation at break EL (%) and conductivity EC (%IACS) were measured as described above, using the formula: X = (EL). 2 The value of parameter X was calculated from × (EC).

[0055] For each copper alloy sheet manufactured as described above in Examples 1 to 3 and Comparative Example 1, the tensile strength, conductivity, and I(200) / I0(200) in the direction parallel to the rolling direction were measured according to the method described earlier. The results are shown in Table 1. In addition, the 0.2% yield strength and elongation of each copper alloy sheet were also measured. The 0.2% yield strength was measured using a tensile testing machine in accordance with JIS Z2241:2011, using the offset method, in the direction parallel to the rolling direction of the copper alloy sheet. Specifically, the tensile strength and elongation mentioned above refer to the elongation at break measured using a tensile testing machine in accordance with JIS Z2241:2011, in the direction parallel to the rolling direction of the copper alloy sheet. The results are also shown in Table 1.

[0056]

[0057] All of the copper alloy sheets in Examples 1-3 and Comparative Example 1 exhibited high tensile strength. However, in Comparative Example 1, the parameter X of the semi-finished product was large, resulting in a small I(200) / I0(200) ratio for the copper alloy sheet and a high Young's modulus. In contrast, in Examples 1-3, the parameter X of the semi-finished product was small, and consequently, the I(200) / I0(200) ratio for the copper alloy sheet fell within a predetermined range, resulting in a low Young's modulus.

[0058] These results suggest that the copper alloy of the aforementioned embodiment may have a relatively high strength and a relatively low Young's modulus.

[0059] (Potential Contribution to SDGs) According to the embodiment described above, it is possible to provide a copper alloy that has a relatively high strength and a relatively low Young's modulus, which may contribute to improving the functionality and reliability of electronic devices. Improving the functionality and reliability of electronic devices is essential for realizing an AI / IoT society. Therefore, this embodiment may contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs): "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation."

Claims

1. A copper alloy containing 1.5% by mass or more and 4.6% by mass or less of Ni, 0.10% by mass or more and 0.80% by mass or less of Co, and 0.10% by mass or more and 1.3% by mass or less of Si, with the remainder being Cu and unavoidable impurities, wherein the ratio (I(200) / I0(200)) of the integrated intensity I(200) of the peak of the (200) plane obtained by X-ray diffraction measurement on the surface of the copper alloy to the integrated intensity I(200) of the peak of the (200) plane obtained by X-ray diffraction measurement on a standard pure copper powder is 3.0 or more and 10.0 or less, and the tensile strength in the direction parallel to the rolling direction is 850 MPa or more.

2. The copper alloy according to claim 1, further containing a total of 0.010% by mass or more and 5.0% by mass or less of one or more elements selected from the group consisting of Mg, Fe, P, Cr, Ag, Zn, Sn, Pb, Zr, Al, As, Se, Te, Sb, Bi, Au, Ti, Nb, V, Ta, W, Mo, and Mn.

3. The copper alloy according to claim 1, further containing 0.010% by mass or more and 0.50% by mass or less of Cr.

4. The copper alloy according to claim 1, wherein I(200) / I0(200) is 8.1 or less.

5. The copper alloy according to claim 1, wherein I(200) / I0(200) is 3.1 or greater.

6. The copper alloy according to claim 1, wherein the tensile strength in a direction parallel to the rolling direction is 900 MPa or more.

7. The copper alloy according to claim 6, wherein the tensile strength in a direction parallel to the rolling direction is 921 MPa or more.

8. The copper alloy according to claim 1, wherein the electrical conductivity in a direction parallel to the rolling direction is 35.0% IACS or higher.

9. The copper alloy according to claim 8, wherein the electrical conductivity in a direction parallel to the rolling direction is 37.6% IACS or higher.

10. The copper alloy according to claim 1, wherein the Young's modulus in the direction parallel to the rolling direction is 120 GPa or less.

11. The copper alloy according to claim 10, wherein the Young's modulus in the direction parallel to the rolling direction is 10⁶ GPa or less.

12. The copper alloy according to claim 1, wherein the Young's modulus in the direction parallel to the rolling direction is 90 GPa or more.

13. An electronic component comprising the copper alloy described in any one of claims 1 to 12.

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