Copper alloy and electronic component

Abstract

The purpose of the present disclosure is to provide: a copper alloy having a high conductivity and a high strength; and an electronic component containing the same. A copper alloy according to the present disclosure contains 2.3-4.6 mass% of Ni, 0.10-0.50 mass% of Co, 0.60-1.3 mass% of Si, and 0.010-0.10 mass% of Cr, the remaining portion being Cu and unavoidable impurities.

Description

Copper alloys and electronic parts

[0001] The present invention relates to a copper alloy and an electronic component.

[0002] Corson alloys are alloys in which intermetallic compounds such as Ni-Si, Co-Si, and Ni-Co-Si are precipitated in a Cu matrix, and they have both high strength and high electrical conductivity. Because of these properties, Corson alloys can be used as copper alloy components in electronic components, for example, as lead frames that support and fix semiconductor elements in semiconductor packages and form internal wiring (see, for example, Patent Document 1).

[0003] JP 2018-035437 A

[0004] As electronic components have become more sophisticated in recent years, copper alloy components (or specific portions of copper alloy components) made from Corson copper alloys, which are included in electronic components, have become increasingly miniaturized. This has led to demands for copper alloys that maintain high electrical conductivity while also improving their properties to accommodate this miniaturization. For example, in semiconductor packages, which are electronic components, the increasing functionality of semiconductor packages has led to increasingly compact structures and even larger packages. Therefore, efforts are being made to miniaturize lead frames made from copper alloys used to construct semiconductor packages, particularly the leads within the lead frames. Leads are the internal wiring (pins) that connect to external wiring within a semiconductor package. Miniaturization of leads has led to increased lead length and narrower lead pitches. However, such miniaturization can make it difficult for the leads to have sufficient strength, and the leads can be deformed and difficult to maintain their shape with high precision during the manufacturing process of lead frames and semiconductor packages (for example, a process of manufacturing a desired lead frame by half-etching a copper alloy plate, or a process of arranging a semiconductor element on a lead frame and then wire-bonding the leads to connect the semiconductor element.) As a result, semiconductor packages cannot be manufactured efficiently in some cases, and further improvement in the strength of copper alloys is required.

[0005] The present disclosure aims to provide a copper alloy having high electrical conductivity and high strength, and an electronic component including the same.

[0006] In one embodiment, the copper alloy of the present disclosure is a copper alloy containing 2.3 to 4.6 mass% Ni, 0.10 to 0.50 mass% Co, 0.60 to 1.3 mass% Si, 0.010 to 0.10 mass% Cr, and the balance being Cu and unavoidable impurities.

[0007] In one embodiment, the electronic component of the present disclosure is an electronic component containing the copper alloy of the present disclosure.

[0008] The present disclosure can provide a copper alloy having high electrical conductivity and high strength, and an electronic component including the same.

[0009] FIG. 1 is a graph in which the properties of the copper alloys of Example 1 and Comparative Examples 1 and 2 are plotted against the amount of Co (mass%), and a linear approximation curve is drawn. The first axis represents tensile strength, and the second axis represents electrical conductivity. The square plots represent tensile strength, and the circle plots represent electrical conductivity. FIG. 2 shows the properties of the copper alloys of Example 1 and Comparative Examples 1 and 2 plotted against the mass ratio R of Co to Ni. B This graph plots the tensile strength against the conductivity, and a linear approximation curve is drawn. The first axis represents the tensile strength, and the second axis represents the conductivity. The square plots represent the tensile strength, and the circle plots represent the conductivity.

[0010] Hereinafter, an embodiment of the present disclosure (hereinafter also referred to as "the present embodiment") will be described in detail, but the present invention is not limited to the following embodiment. 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.

[0011] [Copper Alloy] The copper alloy of this embodiment contains 2.3 to 4.6 mass% Ni, 0.10 to 0.50 mass% Co, 0.60 to 1.3 mass% Si, 0.010 to 0.10 mass% Cr, and the balance being Cu and unavoidable impurities. That is, the copper alloy of this embodiment is a Cu-Ni-Co-Si alloy. By subjecting Ni, Co, and Si to appropriate heat treatment, they form precipitated particles of a Ni-Co-Si intermetallic compound, which can achieve high electrical conductivity and high strength.

[0012] In the composition of the copper alloy of this embodiment, the Ni concentration is 2.3 to 4.6 mass%, the Co concentration is 0.10 to 0.50 mass%, and the Cr concentration is 0.010 to 0.10 mass%. This allows the strength of the copper alloy to be further improved while maintaining high electrical conductivity. If the Ni concentration is less than 2.3 mass%, the desired strength cannot be obtained. If the Co concentration is less than 0.10 mass%, the desired strength and electrical conductivity cannot be obtained. If the Cr concentration is less than 0.010 mass%, the desired strength cannot be obtained. If the Ni concentration exceeds 4.6 mass%, sufficient strength is obtained, but electrical conductivity decreases. Furthermore, if the Co concentration exceeds 0.50 mass%, sufficient electrical conductivity is obtained, but high strength is difficult to obtain. If the Cr concentration exceeds 0.10 mass%, Cr forms a compound with other contained components, making it difficult to form the desired Ni-Co-Si-based precipitates. As a result, the desired strength cannot be obtained. The Ni concentration is preferably 2.8 to 4.4 mass%, more preferably 3.0 to 4.0 mass%, and even more preferably 3.3 to 3.7 mass%. The Co concentration is preferably less than 0.50 mass%, more preferably 0.10 to 0.40 mass%, and even more preferably 0.20 to 0.30 mass%. The Cr concentration is preferably 0.020 to 0.070 mass%, and even more preferably 0.040 to 0.060 mass%.

[0013] In the composition of the copper alloy of this embodiment, the Si concentration is 0.6 to 1.3 mass%. This allows the strength of the copper alloy to be further improved while maintaining high electrical conductivity. If the Si concentration is less than 0.60 mass%, the desired strength cannot be obtained. On the other hand, if the Si concentration exceeds 1.3 mass%, sufficient strength is obtained, but electrical conductivity is reduced. The Si concentration is preferably 0.7 to 1.2 mass%, and more preferably 0.8 to 1.0 mass%.

[0014] As mentioned above, Ni-Co-Si-based precipitates formed by Ni, Co, and Si are considered to be intermetallic compounds mainly composed of (Ni + Co)Si. However, not all of the Ni, Co, and Si in the copper alloy become precipitates by aging treatment during the manufacturing process of the copper alloy sheet, and some of them may exist in a solid solution state in the Cu matrix. Although the solid solution state of Ni, Co, and Si can slightly improve the strength of the copper alloy sheet, the effect is smaller than that of the precipitated state, and they may also be a factor in reducing the electrical conductivity. Therefore, it is preferable that the content ratio of Ni, Co, and Si is close to the composition ratio of (Ni + Co)Si. Therefore, the ratio R of the total mass of Ni and Co to Si is A is preferably 3.5 to 5.0, more preferably 3.5 to 4.5.

[0015] As described above, Ni—Co—Si-based precipitates contribute to improving the strength and electrical conductivity of copper alloys, and Ni tends to mainly contribute to improving the strength of copper alloys, while Co tends to mainly contribute to improving the electrical conductivity of copper alloys. Therefore, from the viewpoint of improving the strength of copper alloys while maintaining high electrical conductivity, the mass ratio R of Co to Ni is B The mass ratio R of Co to Ni can be 0.010 to 0.155. B When the mass ratio R of Co to Ni is 0.010 or more, the high electrical conductivity of the copper alloy can be maintained. B When the ratio R is 0.155 or less, the strength of the copper alloy can be effectively improved. B is preferably 0.025 to 0.155, more preferably 0.056 to 0.086.

[0016] In addition to the above elements, the copper alloy of this embodiment may further 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 (hereinafter also referred to as "additive elements") in a total amount of 0.010 to 1.0 mass%. This can improve the strength, heat resistance, stress relaxation resistance, and the like of the copper alloy. When the total amount of additive elements is 0.010 mass% or more, the desired effects described above tend to be easily achieved. Furthermore, when the total amount of additive elements is 1.0 mass% or less, it is possible to prevent a decrease in electrical conductivity while obtaining the desired properties. The total amount of additive elements is preferably 0.020 to 0.080 mass%, and more preferably 0.050 to 0.080 mass%.

[0017] In this embodiment, the remainder, which is the components other than those described above, consists of Cu and inevitable impurities. Here, inevitable impurities refer to impurity elements that are unavoidably mixed into the material during the manufacturing process. The concentration of each element of the inevitable impurities can be, for example, 0.015 mass% or less, preferably 0% (undetectable). The composition of the copper alloy can also be measured by wet analysis. Ni may be determined using the copper separation dimethylglyoxime gravimetric method (JIS-H1056 (2003)), and Si may be determined using the silicon dioxide gravimetric method (JIS-H1061 (2006)). Other additive elements and impurity elements may be determined using ICP atomic emission spectroscopy. Analysis of other additive elements is performed using an internal standard method, with Y (yttrium) used as the internal standard. An element other than Y may also be selected as the internal standard. ICP atomic emission spectroscopy is performed using a Hitachi High-Tech Science Corporation ICP atomic emission spectroscopy (ICP-OES) SPS3100 or an equivalent device. In the case of 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. The composition of the copper alloy may also be measured using X-ray fluorescence analysis. The X-ray fluorescence analyzer used may be a Rigaku Simultix 14 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 to 40 mm diameter and 50 to 80 mm thick, then cut to a thickness of approximately 10 to 20 mm, and the cut surface is used as the analysis surface. X-ray fluorescence analysis is performed in accordance with JIS K 0119:2008, using a wavelength dispersive method.

[0018] The copper alloy of this embodiment can be made into a copper alloy plate by, for example, a manufacturing method including a rolling step as described below, though it is not particularly limited thereto. The copper alloy plate is not particularly limited as long as it has the above-described composition and is a three-dimensional object with a predetermined thickness. The "plate" in this copper alloy plate also includes sheet, strip, and foil. Furthermore, this copper alloy plate includes not only copper alloy plates before processing for use in, for example, electronic components, but also copper alloy plates during or after processing. The thickness of the copper alloy plate is, for example, 0.030 to 1.2 mm. The thickness is preferably 0.050 to 0.60 mm, more preferably 0.080 to 0.30 mm.

[0019] The copper alloy of this embodiment has high electrical conductivity and strength due to its composition as described above. Specifically, the copper alloy of this embodiment may have a tensile strength of 870 MPa or more in a direction parallel to the rolling direction in a copper alloy sheet produced through a rolling process. Because of this high tensile strength, it is possible to suppress deformation that may occur in a series of steps leading up to the production of an electronic component, including a step of processing a copper alloy sheet to produce a copper alloy component (e.g., a lead frame), for a finely divided copper alloy component for an electronic component produced from the copper alloy. The tensile strength in a direction parallel to the rolling direction is preferably 930 MPa or more, more preferably 940 MPa or more, and even more preferably 950 MPa or more. The upper limit of the tensile strength in a direction parallel to the rolling direction is not particularly limited, but the tensile strength may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0020] The tensile strength in the direction parallel to the rolling direction can be measured using a tensile tester in accordance with JIS-Z2241 (2011). Specifically, a JIS No. 13B test piece is prepared from each sample using a press so that the tensile direction is parallel to the rolling direction. The tensile test conditions are a test piece width of 12.5 mm, a measurement temperature of room temperature (15 to 35°C), a tensile speed of 5 mm / min, and a gauge length of 50 mm. Two test pieces are used for the test, and the average of the two data points can be used as the tensile strength in the direction parallel to the rolling direction in this disclosure. The above tensile speed corresponds to the crosshead displacement speed specified in the JIS standard. An Autocom AC-100KN-C manufactured by TSE Corporation or an equivalent device can be used as a tensile tester. Furthermore, the tensile strength in the direction parallel to the rolling direction can be adjusted to a desired range by using the copper alloy composition of the copper alloy of this embodiment described above.

[0021] The copper alloy of this embodiment may have an electrical conductivity of 30% IACS or more. A conductivity of 30% IACS or more allows the copper alloy to be effectively used as a copper alloy component for electronic devices. The electrical conductivity refers to the electrical conductivity in a direction parallel to the rolling direction. Furthermore, the electrical conductivity can be adjusted to a desired range by using the composition of the copper alloy of this embodiment as described above. The electrical conductivity (EC: % IACS) can be measured by a four-terminal method in accordance with JIS-H0505 (1975). A double bridge is used for the measurement, and resistance can be measured based on the average cross-sectional area method. The electrical conductivity can be measured at room temperature (25°C) in a direction parallel to the rolling direction. Due to the convenience of the test sample, the gauge length (distance between electrical resistance measurements) can be set to 50 mm.

[0022] A method for producing a copper alloy sheet will be described below. In this embodiment, the copper alloy sheet can be produced by a method including a rolling step, although it is not particularly limited thereto. Specifically, the copper alloy sheet can be produced, for example, by subjecting an ingot to homogenization, hot rolling, intermediate cold rolling, solution treatment, aging treatment, finish cold rolling, and stress relief annealing in this order. Cold rolling before the solution treatment is not essential and may be performed as needed. Furthermore, cold rolling may be performed after the solution treatment and before the aging treatment as needed, or the solution treatment and the aging treatment may each be performed two or more times. After each of the above steps is performed, grinding, polishing, shot blasting, pickling, etc. may be performed as appropriate to remove oxide scale from the surface.

[0023] An example of a method for producing a copper alloy sheet that can be produced using the copper alloy of this embodiment by a method including a rolling step will be described in more detail. The method for producing a copper alloy sheet may first include a step of melting and casting a copper alloy raw material having the desired composition described above. In this step, the copper alloy raw material is melted using a method similar to a general copper alloy melting method, and then an ingot is produced by continuous casting, semi-continuous casting, or the like. For example, first, an atmospheric melting furnace is used to melt raw materials such as electrolytic copper, Ni, Co, Si, and Cr to obtain a molten metal with the desired composition. This molten metal is then poured into a mold of desired dimensions and cast into an ingot.

[0024] In this embodiment, the method for producing a copper alloy sheet may include a step of hot rolling an ingot that has been subjected to homogenization annealing. The hot rolling of the ingot is not particularly limited, but may be performed, for example, in several passes at 500 to 950°C. The total reduction ratio of the hot rolling is preferably 90% or more.

[0025] Solution treatment is a heat treatment that dissolves silicides such as Ni-Si compounds, Co-Si compounds, and Ni-Co-Si compounds in a Cu matrix and simultaneously recrystallizes the Cu matrix. The solution heat treatment temperature is not particularly limited, but can be, for example, 650 to 1000°C. The heat treatment time can be 1 second to 10 minutes. Specifically, by setting the solution treatment temperature and time at or above the lower limits of the above ranges, even if a large amount of silicides such as Ni-Co-Si compounds is contained in the copper alloy, they can be easily dissolved sufficiently in the Cu matrix and recrystallized. By setting the solution treatment temperature and time at or below the upper limits of the above ranges, coarsening of recrystallized grains can be easily suppressed. The heat treatment temperature is preferably 700 to 950°C, and the heat treatment time is preferably 5 seconds to 5 minutes.

[0026] In this embodiment, the method for producing a copper alloy sheet may include a step of aging the intermediate body after the solution treatment. The heat treatment temperature for the aging treatment is not particularly limited, but may be, for example, 375 to 625°C. The heat treatment time may be 0.5 to 50 hours. By setting the aging temperature and time at or above the lower limits of the above ranges, sufficient amounts of Ni-Si compounds, Co-Si compounds, and Ni-Co-Si compounds are precipitated, tending to provide sufficient strength. By setting the aging temperature and time at or below the upper limits of the above ranges, coarsening of precipitates and re-dissolution can be prevented, making it easier to sufficiently improve strength and electrical conductivity. In order to sufficiently increase the strength and electrical conductivity of a copper alloy, it is important to increase the tensile strength and electrical conductivity of the intermediate body after the aging treatment in a direction parallel to the rolling direction. For example, to achieve a tensile strength of 870 MPa or more of the copper alloy, the tensile strength of the intermediate body after the aging treatment may be set to 750 MPa or more. In order to make the tensile strength of the copper alloy 930 MPa or more, the tensile strength of the intermediate body after aging treatment may be 830 MPa or more. In order to make the tensile strength of the copper alloy 950 MPa or more, the tensile strength of the intermediate body after aging treatment may be 850 MPa or more. For example, the electrical conductivity of the intermediate body after aging treatment in a direction parallel to the rolling direction may be 40% IACS or more. The aging treatment is preferably performed in an inert atmosphere such as Ar, N, or H to suppress the generation of an oxide film.

[0027] In this embodiment, the method for producing a copper alloy sheet may include a step of performing finish cold rolling on the intermediate body. The finish cold rolling is not particularly limited, but may be performed in several passes, for example. It is preferable to perform one or more passes of rolling. The total reduction ratio of the finish cold rolling is preferably 40% or more. Finish cold rolling can impart processing strain to the material, improving its strength. The upper limit of the reduction ratio of the finish cold rolling is preferably 90% or less. A reduction ratio of 90% or less can prevent a decrease in electrical conductivity due to processing strain from heavy processing. The reduction ratio (%) is expressed as the reduction ratio (%) = [(TB - TA) / TB] × 100, where TB is the thickness of the workpiece to be rolled and TA is the thickness of the workpiece after rolling.

[0028] In this embodiment, the method for producing a copper alloy sheet may include a step of performing stress relief annealing on the intermediate body after the above-mentioned finish cold rolling. The stress relief annealing may be performed under general conditions, for example, at 250°C to 550°C and for a holding time of 5 seconds to 5 hours. The stress relief annealing may be performed in air or in an inert atmosphere such as nitrogen or argon gas. Furthermore, the copper alloy sheet after stress relief annealing may be cooled by air cooling.

[0029] In this embodiment, the copper alloy sheet can be manufactured by a manufacturing method including the above steps. In this manufacturing method, pickling, polishing, degreasing, facing, and trimming may be performed as necessary after each rolling step and each heat treatment step. In addition, this manufacturing method may include rolling steps and heat treatment steps other than those described above.

[0030] [Electronic Component] The electronic component of this embodiment is an electronic component containing the copper alloy of this embodiment described above. More specifically, the electronic component of this embodiment contains a copper alloy component manufactured from the copper alloy of this embodiment via a copper alloy plate. Examples of electronic components include semiconductor packages. Since the miniaturized copper alloy components manufactured from the copper alloy of this embodiment have properties that suppress deformation during the manufacturing process of electronic components, the copper alloy of this embodiment is suitable for manufacturing semiconductor packages with many miniaturized structures. When the electronic component is a semiconductor package, the semiconductor package can be manufactured, for example, by, but not limited to, manufacturing a lead frame using a copper alloy plate manufactured from the copper alloy of this embodiment, supporting and fixing a semiconductor element on the lead frame, wire-bonding the semiconductor element to the leads to form internal wiring, and then encapsulating the semiconductor element with a predetermined resin material. As described above, the electronic component of this embodiment may contain the copper alloy of this embodiment.

[0031] Although the embodiments of the present disclosure have been described above, the copper alloy and electronic component of the present disclosure are not limited to the above examples and can be modified as appropriate.

[0032] (Aspects of the Present Disclosure) A first aspect of the present disclosure is a copper alloy containing 2.3 to 4.6 mass% Ni, 0.10 to 0.50 mass% Co, 0.60 to 1.3 mass% Si, 0.010 to 0.10 mass% Cr, and the balance consisting of Cu and unavoidable impurities.

[0033] A second aspect of the present disclosure is the copper alloy according to the first aspect, containing less than 0.50% by weight of Co.

[0034] A third aspect of the present disclosure is the copper alloy according to the first or second aspect, containing 0.10 to 0.40 mass % Co.

[0035] A fourth aspect of the present disclosure is the copper alloy according to any one of the first to third aspects, further comprising 0.20 to 0.30 mass% Co.

[0036] A fifth aspect of the present disclosure is the copper alloy according to any one of the first to fourth aspects, containing 0.020 to 0.070 mass% of Cr.

[0037] A sixth aspect of the present disclosure is the copper alloy according to any one of the first to fifth aspects, containing 3.0 to 4.0 mass% Ni.

[0038] A seventh aspect of the present disclosure is a ratio R of the total mass of Ni and Co to Si. A is 3.5 to 5.0.

[0039] An eighth aspect of the present disclosure is a method for manufacturing a semiconductor device, comprising: A is 3.5 to 4.5.

[0040] A ninth aspect of the present disclosure is a mass ratio R of Co to Ni B is 0.010 to 0.155.

[0041] A tenth aspect of the present disclosure is a method for manufacturing a semiconductor device, comprising: B is 0.025 to 0.155.

[0042] An eleventh aspect of the present disclosure is a method for manufacturing a semiconductor device, comprising: B is 0.056 to 0.086.

[0043] A twelfth aspect of the present disclosure is the copper alloy according to any one of the first to eleventh aspects, further containing 0.010 to 1.0% by mass in total 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.

[0044] A thirteenth aspect of the present disclosure is the copper alloy according to any one of the first to twelfth aspects, wherein the electrical conductivity is 30% IACS or more.

[0045] A fourteenth aspect of the present disclosure is the copper alloy according to any one of the first to thirteenth aspects, wherein the tensile strength in a direction parallel to the rolling direction is 870 MPa or more.

[0046] A fifteenth aspect of the present disclosure is the copper alloy according to any one of the first to fourteenth aspects, wherein the tensile strength in a direction parallel to the rolling direction is 930 MPa or more.

[0047] A sixteenth aspect of the present disclosure is an electronic component comprising the copper alloy according to any one of the first to fifteenth aspects.

[0048] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples. In Example 1, a copper alloy sheet was produced from a desired copper alloy as follows. Using electrolytic copper as a raw material, a copper alloy having the composition shown in Table 1 was melted and cast using an atmospheric melting furnace. The ingot was hot rolled at 950°C to a thickness of 10.0 mm. After hot rolling, the ingot was faced and then intermediate cold rolled to a thickness of 0.167 mm. Thereafter, solution treatment and aging treatment were performed under the conditions shown in Table 1. Next, finish cold rolling was performed to a thickness of 0.1 mm with the working ratio shown in Table 1 to obtain a copper alloy sheet. In Example 2, the copper alloy sheet subjected to finish cold rolling in Example 1 was further subjected to stress relief annealing in the atmosphere under the conditions shown in Table 2. The copper alloy sheet after stress relief annealing was cooled by air cooling to obtain the copper alloy sheet of Example 2.

[0049] In Comparative Examples 1 and 2, copper alloy sheets were produced in the same manner as in Example 1, except that the composition of the copper alloy and the solution treatment conditions were changed to those shown in Table 1. Specifically, in Comparative Example 1, two samples were produced as copper alloy sheets by the same production method as in Example 1, except that the composition of the copper alloy was changed to that shown in Table 1 and the solution treatment temperature was changed to 900°C or 925°C as shown in Table 1. The evaluations of the copper alloy in Comparative Example 1 were carried out by plotting the numerical values ​​of the evaluation results of the two samples (tensile strength and electrical conductivity of the intermediate after aging treatment and the copper alloy sheet after finish cold rolling as shown in Table 1) on the vertical axis and the solution treatment temperature on the horizontal axis, calculating a straight line connecting the plots, and then substituting the value of the solution treatment temperature of 915°C into the mathematical formula representing the straight line, thereby obtaining estimated evaluation results of the copper alloy and its intermediate when produced by performing solution treatment at 915°C. In Comparative Example 2, similarly to Comparative Example 1, the composition of the copper alloy was changed to that shown in Table 1, and the solution treatment temperature was changed to 910°C, 935°C, or 950°C as shown in Table 1. Except for this, three samples were produced as copper alloy sheets by the same production method as in Example 1. The evaluations of the copper alloy of Comparative Example 2 were carried out by plotting the numerical values ​​of the evaluation results of the three samples on the vertical axis and the solution treatment temperature on the horizontal axis, calculating an approximate line connecting the plots (using the approximate line function of Microsoft Excel (registered trademark)), and then substituting the value of the solution treatment temperature of 915°C into the formula representing the approximate line, thereby obtaining estimated evaluation results of the copper alloy and its intermediate when produced by carrying out solution treatment at 915°C.

[0050] The obtained copper alloy sheets of Examples 1 and 2 and the copper alloy sheets of Comparative Examples 1 and 2 were subjected to the following measurements. The results are shown in Tables 1 and 2. [Composition] The composition of the obtained copper alloy was confirmed by X-ray fluorescence analysis. A Simultix 14 manufactured by Rigaku Corporation was used as the X-ray fluorescence analyzer. 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 K 0119:2008, and measurements were made using a wavelength dispersive method.

[0051] [Tensile Strength (TS)] The tensile strength (TS) of the obtained copper alloy sheets was measured in a direction parallel to the rolling direction using a tensile tester in accordance with JIS-Z2241 (2011). Specifically, JIS No. 13B test pieces were prepared from each sample using a press so that the tensile direction was parallel to the rolling direction. The tensile test conditions were as follows: test piece width: 12.5 mm, measurement temperature: room temperature (15 to 35°C), tensile speed (crosshead displacement rate): 5 mm / min, and gauge length (gauge length): 50 mm. The test was performed using two test pieces, and the average values ​​of the two data are shown in Tables 1 and 2.

[0052] [Conductivity] Electrical conductivity (EC: % IACS) was measured by a four-terminal method in accordance with JIS-H0505 (1975). A double bridge was used for the measurement, and resistance was measured based on the average cross-sectional area method. The electrical conductivity was measured at room temperature (25°C) in a direction parallel to the rolling direction. The gage length (distance between electrical resistance measurements) was 50 mm.

[0053]

[0054]

[0055] As shown in Tables 1 and 2, it was found that manufacturing with the desired composition provides high electrical conductivity while improving tensile strength. Therefore, the finely divided copper alloy parts for electronic components manufactured from the copper alloys of Examples 1 and 2 can suppress deformation during the manufacturing process of electronic components. The properties (tensile strength and electrical conductivity) of the copper alloys of Example 1 and Comparative Examples 1 and 2 were plotted against the Co content (mass%), and a linear approximation curve was drawn, as shown in Figure 1. It is believed that as the Co content increases, Co-Si-based precipitates or Ni-Co-Si-based precipitates are formed, improving electrical conductivity. Therefore, a linear approximation curve was created from the experimental values ​​obtained in the examples, and the electrical conductivity for each Co content was predicted. From these results, it can be seen that a Co content of 0.10 mass% or more can achieve an electrical conductivity of 39.7% IACS or higher. It can also be seen that a Co content of 0.20 mass% or higher can achieve an electrical conductivity of 39.8% IACS or higher. It can be seen that if the Co content is 0.25 mass % or more, a conductivity of 40.1% IACS or more can be achieved. The properties (tensile strength and conductivity) of the copper alloys of Example 1 and Comparative Examples 1 and 2 are calculated as a function of the mass ratio R of Co to Ni. B The results are shown in Figure 2, where the linear approximation curve is plotted against the Co / Ni (mass ratio). B As R increases, Co-Si precipitates or Ni-Co-Si precipitates are formed, which makes it easier to obtain electrical conductivity but harder to obtain strength. B From this result, the strength and conductivity at the ratio R B It can be seen that if the ratio R is 0.010 or more, a conductivity of 39.7% IACS or more can be achieved. B It can be seen that if the ratio R is 0.025 or more, a conductivity of 39.7% IACS or more can be achieved. B It can be seen that if the ratio R is 0.056 or more, a conductivity of 39.8% IACS or more can be achieved. B It can be seen that if the ratio R is 0.155 or less, a tensile strength of 938 MPa or more can be achieved. B It can be seen that if the tensile strength is 0.086 or less, a tensile strength of 949 MPa or more can be achieved.

[0056] According to the present disclosure, it is possible to provide a copper alloy having high electrical conductivity and high strength, and an electronic component including the same.

Claims

1. A copper alloy containing 3.0 to 4.0 mass% Ni, 0.20 to 0.50 mass% Co, 0.60 to 1.3 mass% Si, and 0.010 to 0.10 mass% Cr, with the remainder being Cu and unavoidable impurities, and having a tensile strength of 870 MPa or more in a direction parallel to the rolling direction.

2. The copper alloy according to claim 1, which contains less than 0.50% by mass of Co.

3. The copper alloy according to claim 1, containing 0.70 to 1.20% by mass of Si.

4. The copper alloy according to any one of claims 1 to 3, containing 0.010 to 0.070 mass% of Cr.

5. A copper alloy according to any one of claims 1 to 3, containing 0.020 to 0.070 mass% of Cr.

6. The copper alloy according to any one of claims 1 to 3, containing 0.20 to 0.40% by mass of Co.

7. A copper alloy according to any one of claims 1 to 3, containing 0.20 to 0.30 mass% of Co.

8. The copper alloy according to any one of claims 1 to 3, wherein the thickness is 0.030 to 1.2 mm.

9. The copper alloy according to any one of claims 1 to 3, further containing a total of 0.010 to 1.0 mass% of one or more elements selected from the group consisting of Mg, Fe, P, Ag, Sn, Pb, Zr, As, Se, Te, Sb, Bi, Au, Ti, Nb, V, Ta, W, Mo, and Mn.

10. The copper alloy according to claim 9, containing 0.010 to 0.070 mass% of Cr.

11. The copper alloy according to claim 9, comprising 0.020 to 0.070 mass% of Cr.

12. Ratio of the total mass of Ni and Co to Si A The copper alloy according to any one of claims 1 to 3, wherein the coefficient is 3.5 to 5.

0.

13. Ratio of Co mass to Ni mass B The copper alloy according to any one of claims 1 to 3, wherein the coefficient is 0.010 to 0.

155.

14. A copper alloy according to any one of claims 1 to 3, wherein the conductivity is 30% IACS or higher.

15. A copper alloy according to any one of claims 1 to 3, wherein the tensile strength in a direction parallel to the rolling direction is 930 MPa or more.

16. A material containing 2.3 to 4.6 mass of Ni, 0.10 to 0.50 mass% of Co, 0.60 to 1.3 mass% of Si, and 0.010 to 0.070 mass% of Cr, with the remainder being Cu and unavoidable impurities, and having a tensile strength of 870 MPa or more in a direction parallel to the rolling direction. A copper alloy further containing a total of 0.010 to 1.0 mass% of one or more elements selected from the group consisting of Mg, Fe, P, Ag, Zn, Sn, Pb, Zr, Al, As, Se, Te, Sb, Bi, Au, Ti, Nb, V, Ta, W, Mo, and Mn.

17. The copper alloy according to claim 16, comprising 0.020 to 0.070 mass% of Cr.

18. 2.3 to 4.6 mass% Ni, 0.10 to 0.50 mass% Co, 0.60 to 1.3 mass It contains % by amount of Si, 0.010 to 0.070 mass% of Cr, with the remainder being Cu and unavoidable impurities, and the ratio of the mass of Co to Ni (RB) is 0.056 to 0.

086. A copper alloy further containing a total of 0.010 to 1.0 mass% of one or more elements selected from the group consisting of Mg, Fe, P, Ag, Sn, Pb, Zr, As, Se, Te, Sb, Bi, Au, Ti, Nb, V, Ta, W, Mo, and Mn.

19. The copper alloy according to claim 18, comprising 0.020 to 0.070 mass% of Cr.

20. An electronic component comprising the copper alloy described in any one of claims 1 to 3 or 16 to 19.