Copper alloys and electronic components

Abstract

The present invention provides a copper alloy and electronic components that possess a relatively high strength and a relatively low Young's modulus. [Solution] 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 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.

Description

[Technical Field]

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

[0002] Copper alloys in which intermetallic compounds such as Ni-Si, Co-Si, and Ni-Co-Si are deposited in a Cu matrix can be called Corson alloys. Because Corson alloys possess high strength and conductivity, they are sometimes used in copper alloy components of electronic devices, such as lead frames for semiconductor packages and various connection terminals. Examples of technologies related to this type of copper alloy are described in 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 both in total, 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 states that the objective is to "provide 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 property," and that "it has a composition containing 1.0 mass% to 5.0 mass% of Ni and 0.1 mass% to 2.0 mass%, with the remainder being copper and unavoidable impurities, and in crystal orientation analysis by electron backscatter diffraction, the cube orientation is {001} <100> The area fraction of crystal grains having an orientation that is within 15° of the cube orientation is 5% to 50%, and the cube orientation is {001}. <100> A copper alloy plate material is described, characterized in that 40 to 100 crystal grains having an orientation within a 60 μm square area are dispersed therein, with the deviation from the center being within 15°.

[0005] Patent Document 3 aims to "provide a Corson alloy and a method for manufacturing the same that has excellent bendability and a high Young's modulus in the direction perpendicular to rolling," and states that "the rolled material contains 0.8 to 5.0 mass% of one or more of Ni and Co, 0.2 to 1.5 mass% of Si, and the remainder is copper and unavoidable impurities, and the surface of the rolled material has a Cube orientation {001}" <100> The area ratio is 5-80%, and in a cross-section with a depth of 45-55% of the plate thickness, <100> The document describes a "Corson alloy in which the area ratio of crystals oriented 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 then describes a material having a composition that contains 1.80 to 8.00 mass% of one or two of Ni and Co, 0.40 to 2.00 mass% of Si, and the remainder consisting of copper and unavoidable impurities, with the major axis of the crystal grains of the matrix phase being 12 μm or less, {110} <001> The azimuthal density is 4 or higher, {110} <112> A copper alloy sheet material characterized by having an orientation density of 10 or more has been proposed.

[0007] In Patent Document 5, it is stated that "a Corson alloy having excellent bending workability and a high Young's modulus in the rolling orthogonal direction and a method for producing the same are provided." Specifically, "a rolled material containing 0.8 to 5.0 mass% of one or more of Ni and Co and 0.2 to 1.5 mass% of Si, with the balance being copper and inevitable impurities, and on the surface of the rolled material, I , , , , / I 0(200) ≧1.0, and in a cross-section at a depth of 45 to 55% with respect to 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 at the same time has high dimensional accuracy after press working." Specifically, "a rolled material containing 0 to 5.0 mass% of Ni or 0 to 2.5 mass% of Co, with the total amount of Ni + Co being 0.2 to 5 mass% and 0.2 to 1.5 mass% of Si, with the balance being copper and inevitable impurities, and on the surface of the rolled material, 1.0 ≦ I (200) / I 0(200) ≦5.0, and 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" of a copper alloy strip is disclosed.

Prior Art Documents

Patent Documents

[0009] [[ID=۳۳]]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0010] In recent years, with the increasing sophistication of electronic devices, there has been a demand for increasing the number of pins on connection terminals and making the pins thinner in order to handle the increased number of signals. High-strength materials are required to prevent deformation even with thin pins.

[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. [Means for solving the problem]

[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, 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, 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 contain the above copper alloy.

Advantages of the Invention

[0015] The above copper alloy has a certain degree of high strength and a relatively low Young's modulus.

Brief Description of the Drawings

[0016] [Figure 1] It is a graph showing an example of the relationship between parameter X of the semi-finished product after solution treatment and the degree of orientation of the copper alloy.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the above copper alloy and electronic components will be described in detail. The copper alloy of one embodiment contains 1.5 mass% or more and 4.6 mass% or less of Ni, 0.10 mass% or more and 0.80 mass% or less of Co, and 0.10 mass% or more and 1.3 mass% or less of Si, and the balance consists of Cu and inevitable impurities.

[0018] When X-ray diffraction measurement is 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 X-ray diffraction measurement of the pure copper standard powder is 3.0 or more 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. Further, the above copper alloy has a tensile strength of 850 MPa or more in the direction parallel to the rolling direction and is high in strength.

[0019] (Composition) The Ni content of the copper alloy is 1.5 mass% or more and 4.6 mass% or less, preferably 2.0 mass% or more and 4.6 mass% or less, more preferably 2.3 mass% or more and 4.6 mass% or less, and still more preferably 3.0 mass% or more and 4.3 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 process; some may exist in a solid solution state within 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 reduce electrical 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, and stress relaxation resistance 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 this solution is diluted before use. Furthermore, the composition of the copper alloy may be measured using X-ray fluorescence analysis. A Simultix14 manufactured by Rigaku Corporation or a substantially equivalent device can be used as the X-ray fluorescence analyzer. 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, using the wavelength dispersion method.

[0028] (XRD integrated intensity ratio) When X-ray diffraction (XRD) is performed on the surface of a copper alloy, the integrated intensity I(200) of the peak of the (200) plane obtained is such that the ratio (I(200) / I0(200)) to the integrated intensity I0(200) of the peak of the (200) plane obtained when X-ray diffraction is performed on a standard pure copper powder is 3.0 or greater and 10.0 or less. This results in a Cube orientation {001} with a low Young's modulus. <100> Because a large proportion of the crystal grains are oriented in a certain direction, it can be said that this is a copper alloy with a low Young's modulus.

[0029] If I(200) / I0(200) is less than 3.0, then the cube orientation {001} <100> As the proportion of grains oriented in a certain direction decreases, the Young's modulus increases. From this viewpoint, it is preferable that I(200) / I0(200) be 3.1 or greater. 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 less. It is preferable that I(200) / I0(200) be 3.1 or greater and 8.1 or less.

[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 on 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 on 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. 2 The 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. ·Incidence X-ray source: CoKα (1.789Å) Goniometer length: 300mm ·Optical system: Concentration method • Incident solar slit: 2.5° • Entrance slit: 1 / 2° • Longitudinal limiting slit: 10mm Attachment: ASC-48 • Light receiving slit 1:20mm • Solar light receiving slit: 2.5° • Light receiving slit 2: OPEN • Attenuator: OPEN • Detector: 1D detector D / teX Ultra 250 (1D mode) • Monochromaticization: Multilayer mirror • Kβ filter: 1D filter for Co (Fe 0.019mm) • Tube voltage: 40kV ·Tube current: 25mA • Scan axis: 2θ-θ Command scan mode FT scan Counting time: 0.12 seconds • Counting speed: 10° / min • Sampling step: 0.02° • Gamma fluctuation: Present • Fitting range: Same range as measurement range ·Smoothing: Savitzky-Golay smoothing (smoothing points: 5 points) • Background type: B-spline • Peak shape used for fitting: Split 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, σ is set to σ0, and ε' = ε + σ0 / m is set, 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 preferably has a tensile strength of 850 MPa or more, 900 MPa or more, and more preferably 921 MPa or more, in the direction parallel to the rolling direction. 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 No. 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 speed) 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% yield strength) The 0.2% yield strength of the copper alloy in the direction parallel to the rolling direction may be 850 MPa or higher, 900 MPa or higher, or 925 MPa or higher. With such high strength, deformation is effectively suppressed even in thin-walled pins of connecting terminals. The upper limit of the 0.2% yield strength of the copper alloy in the direction parallel to the rolling direction is not particularly limited, but may be, for example, 1100 MPa or lower, 1050 MPa or lower, 1000 MPa or lower, or 960 MPa or lower.

[0036] The 0.2% yield strength of copper alloys is measured using a tensile testing machine in accordance with JIS Z2241:2011, in a direction parallel to the rolling direction (offset method, 0.2%). Specifically, test specimens are prepared using the same method as described above for tensile strength. The test is also performed under the same conditions as described above for tensile strength.

[0037] (conductivity) The conductivity of the copper alloy in the direction parallel to the rolling direction is preferably 35.0% IACS or higher, and more preferably 37.6% IACS or higher. This allows the copper alloy to be used well in electronic components. However, the conductivity of the copper alloy in the direction parallel to the rolling direction may be, for example, 55.0% IACS or lower, typically 50.0% IACS or lower.

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

[0039] (Elongation at break) The elongation at break of copper alloys is measured in a direction parallel to the rolling direction using a tensile testing machine in accordance with JIS Z2241:2011. Specifically, test specimens are prepared using the same method as described above for tensile strength. The test is also performed under the same conditions as described above for tensile strength. The elongation at break is calculated using the following formula. The definitions of final gauge length and original gauge length are the same as in JIS Z2241:2011. Elongation at break (%) = (Final gauge length - Original gauge length) ÷ Original gauge length

[0040] (shape) Copper alloys can be in the form of strips or plates, and this also includes sheets. Copper alloys include copper alloy strips and copper alloy plates. When copper alloy plates are thin (for example, less than 0.10 mm), they are sometimes called copper alloy foils.

[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 0.08 mm to 0.30 mm. The thickness of the copper alloy is measured using a micrometer in accordance with JIS B7502. A Mitutoyo BMS-25MX or equivalent micrometer is used.

[0042] (Manufacturing method) The methods for producing the copper alloys described above 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 to cast a copper alloy ingot 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 remainder being Cu and unavoidable impurities. Next, the ingot is subjected to arbitrary homogenization annealing, then processed into a plate shape by hot rolling, and further cold rolling is performed as needed to achieve the desired 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> There is a method to develop the Cube orientation by sufficiently heating during the solution treatment to promote recrystallization and subsequent grain growth. This increases the degree of crystal orientation (I(200) / I0(200)) of the copper alloy produced. Specifically, the parameter X described later in 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, to develop the Cube orientation, it is important to introduce strain by performing cold rolling immediately before the solution treatment. In addition, 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 the 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 between 1000 and 4000. 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 cold rolling before solution treatment can be 10% to 95%. Each condition can be set as appropriate so that X reaches a predetermined value. The degree of processing (%) is expressed as follows: if TB is the thickness of the workpiece before rolling and TA is the thickness of the workpiece after rolling, then the degree of processing (%) = [(TB-TA) / TB] × 100.

[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 temperatures 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 appropriate temperatures and times, Ni-Co-Si compounds can be sufficiently precipitated, and the coarsening and re-solution 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, and 0.10% by mass or more and 1.3% by mass or less of Si, with the remainder being Cu and unavoidable impurities, The ratio (I(200) / I0(200)) of the integrated intensity I(200) of the peak of the (200) plane obtained from X-ray diffraction measurements on the surface of the copper alloy to the integrated intensity I(200) of the peak of the (200) plane obtained from X-ray diffraction measurements on a standard pure copper powder is 3.0 or greater and 10.0 or less. A copper alloy having a tensile strength of 850 MPa or more in a direction parallel to the rolling direction. (2) The copper alloy described in (1) above, further containing a total of 0.010 mass% or more and 5.0 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) A copper alloy according to any of (1) to (3), wherein the ratio I(200) / I0(200) is 8.1 or less. (5) A copper alloy according to any of (1) to (4), wherein the ratio I(200) / I0(200) is 3.1 or greater. (6) A copper alloy according to any of (1) to (5), having a tensile strength of 900 MPa or more in a direction parallel to the rolling direction. (7) A copper alloy according to any of (1) to (6), having a tensile strength of 921 MPa or more in a direction parallel to the rolling direction. (8) A copper alloy according to any of (1) to (7), wherein the electrical conductivity in a direction parallel to the rolling direction is 35.0% IACS or higher. (9) A copper alloy according to any of (1) to (8), wherein the electrical conductivity in a direction parallel to the rolling direction is 37.6% IACS or higher. (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 the direction parallel to the rolling direction is 90 GPa or more. (13) An electronic component containing a copper alloy as described in any of (1) to (12). [Examples]

[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 an exhaustive list.

[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, and 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 1-3 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 previously described method. 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] [Table 1]

[0057] All 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 the SDGs) According to the embodiment described above, it is possible to provide a copper alloy with 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

[Claim 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, Integrated intensity I of the (200) plane peak obtained by X-ray diffraction measurement of pure copper standard powder 0 The ratio 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 (200) (I(200) / I 0 (200)) is 3.0 or more and 10.0 or less, A copper alloy having a tensile strength of 850 MPa or more in a direction parallel to the rolling direction.

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