Copper alloy and electronic component

Abstract

To provide: copper alloy having a high electric conductivity and high strength; and an electronic component including the copper alloy.SOLUTION: Copper alloy of the present disclosure includes 2.3-4.6 mass% of Ni, 0.10-0.50 mass% of Co, 0.60-1.3 mass% of Si, 0.010-0.10 mass% of Cr, and the rest that is Cu and inevitable impurities.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to copper alloys and electronic components.

Background Art

[0002] The Colson alloy is an alloy in which intermetallic compounds such as Ni—Si, Co—Si, and Ni—Co—Si are precipitated in a Cu matrix, and has both high strength and high electrical conductivity. Because of such characteristics, the Colson alloy can be used as a copper alloy component in electronic components, for example, as a lead frame that supports and fixes semiconductor elements and forms internal wiring in a semiconductor package (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the recent high functionality of electronic components, copper alloy components (or specific parts in copper alloy components) made of the copper alloy of the Colson alloy included in electronic components have been highly miniaturized, and for copper alloys, while having high electrical conductivity, further improvement in characteristics corresponding to such miniaturization is required. For example, in a semiconductor package as an electronic component, due to the increasing high functionality in recent years, the structure of the semiconductor package has become more refined, and furthermore, the package itself may become larger. Therefore, miniaturization is also being promoted for lead frames manufactured from copper alloys for constructing semiconductor packages, particularly for the leads within the lead frame. The lead is the portion that becomes the internal wiring (pin) for connecting to external wiring within the semiconductor package. Due to the miniaturization of the lead, the lead length has increased and the pitch between each lead has become narrower. However, due to such miniaturization, the lead may not have sufficient strength, and in the manufacturing processes of the lead frame and semiconductor package (for example, the process of manufacturing a desired lead frame from a copper alloy plate by half etching, or the process of wire bonding to connect the lead and the semiconductor element after arranging the semiconductor element on the lead frame), the lead may deform and it may be difficult to maintain its shape with high precision. As a result, the semiconductor package may not be manufactured sufficiently efficiently, and further improvement in strength is required for copper alloys.

[0005] An object of the present disclosure is to provide a copper alloy having high conductivity and high strength and an electronic component including the same.

Means for Solving the Problem

[0006] In one embodiment, the copper alloy of the present disclosure is a copper alloy 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, 0.010 to 0.10 mass% of Cr, and the balance consisting of Cu and unavoidable impurities.

[0007] In one embodiment, the electronic component of the present disclosure is an electronic component including the above-described copper alloy of the present disclosure.

Effect of the Invention

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

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure (hereinafter also referred to as "the present embodiments") will be described in detail, but the present invention is not limited to the following embodiments. In the present disclosure, "A to B" means "A or more and B or less". Here, A and B represent numerical values.

[0011] [Copper alloy] The copper alloy of the present embodiment contains 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 0.10 mass% of Cr, and the balance is composed of Cu and unavoidable impurities. That is, the copper alloy of the present embodiment is a Cu-Ni-Co-Si based alloy. Ni, Co, and Si can form precipitation particles of Ni-Co-Si based intermetallic compounds by performing appropriate heat treatment, thereby achieving high conductivity and high strength.

[0012] In the composition of the copper alloy of the present embodiment, the concentration of Ni is 2.3 to 4.6 mass%, the concentration of Co is 0.10 to 0.50 mass%, and the concentration of Cr is 0.010 to 0.10 mass%. Thereby, the strength of the copper alloy can be further improved while maintaining the high conductivity of the copper alloy. When the Ni concentration is less than 2.3% by mass, the desired strength cannot be obtained. When the Co concentration is less than 0.10% by mass, the desired strength and conductivity cannot be obtained. When the Cr concentration is less than 0.010% by mass, the desired strength cannot be obtained. When the Ni concentration exceeds 4.6% by mass, sufficient strength can be obtained, but it causes a decrease in conductivity. Also, when the Co concentration exceeds 0.50% by mass, sufficient conductivity can be obtained, but it is difficult to obtain high strength. When the Cr concentration exceeds 0.10% by mass, Cr forms a compound with other components, making it difficult to form the target Ni-Co-Si-based precipitate. As a result, the desired strength cannot be obtained. The Ni concentration is preferably 2.8 to 4.4% by mass, more preferably 3.0 to 4.0% by mass, and even more preferably 3.3 to 3.7% by mass. Also, the Co concentration is preferably less than 0.50% by mass, more preferably 0.10 to 0.40% by mass, and even more preferably 0.20 to 0.30% by mass. The Cr concentration is preferably 0.020 to 0.070% by mass, more preferably 0.040 to 0.060% by mass.

[0013] In the composition of the copper alloy of this embodiment, the Si concentration is 0.6 to 1.3% by mass. Thereby, while maintaining the high conductivity of the copper alloy, the strength of the copper alloy can be further improved. When the Si concentration is less than 0.60% by mass, the desired strength cannot be obtained. Also, when the Si concentration exceeds 1.3% by mass, sufficient strength can be obtained, but it causes a decrease in conductivity. The Si concentration is preferably 0.7 to 1.2% by mass, more preferably 0.8 to 1.0% by mass.

[0014] The Ni-Co-Si-based precipitate formed by Ni, Co, and Si is considered to be an intermetallic compound mainly composed of (Ni + Co)Si as described above. However, Ni, Co, and Si in the copper alloy do not all precipitate during the aging treatment in the manufacturing process of the copper alloy sheet, and to some extent, they can exist in a solid-solution state in the Cu matrix. Ni, Co, and Si in the solid-solution state can slightly improve the strength of the copper alloy sheet, but the effect is smaller compared to the precipitated state, and it can also be a factor in reducing the conductivity. Therefore, the ratio of the contents of Ni, Co, and Si is preferably close to the composition ratio of (Ni + Co)Si. Thus, the mass ratio R A of the total mass of Ni and Co to Si is preferably 3.5 to 5.0, more preferably 3.5 to 4.5.

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

[0016] In the composition of the copper alloy of this embodiment, as elements other than the above elements, 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") can be further contained in a total amount of 0.010 to 1.0% by mass. Thereby, the strength, heat resistance, stress relaxation resistance, etc. of the copper alloy can be improved. When the total amount of the additive elements is 0.010% by mass or more, there is a tendency that the above-mentioned desired effects are easily obtained. Also, when it is 1.0% by mass or less, it is possible to prevent the conductivity from decreasing while obtaining the desired characteristics. The total amount of the additive elements is preferably 0.020 to 0.080% by mass, more preferably 0.050 to 0.080% by mass.

[0017] In this embodiment, the balance, which is a component other than the above, consists of Cu and unavoidable impurities. Here, unavoidable impurities mean impurity elements that cannot be avoided from being mixed into the material during the manufacturing process. The concentration of each element of the unavoidable impurities can be, for example, 0.015% by mass or less, preferably 0% (undetectable). The composition of the copper alloy can also be measured by wet analysis. Ni can be well measured using the copper separation dimethylglyoxime gravimetric method (JIS-H1056(2003)), and Si can be well measured using the silicon dioxide gravimetric method (JIS-H1061(2006)). For other additive elements and impurity elements, ICP emission spectrometry may be used. The analysis of other additive elements is performed using the internal standard method, and Y (yttrium) is used as the internal standard substance for analysis. An element other than Y may be selected as the internal standard substance. The ICP emission spectrometry is measured using an ICP emission spectrometer (ICP-OES) SPS3100 manufactured by Hitachi High-Tech Science Corporation or an equivalent device. In the case of ICP emission spectrometry, a sample of the copper alloy 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) is diluted and used. In addition, the composition of the copper alloy may be measured using X-ray fluorescence analysis. As the X-ray fluorescence analyzer, Rigaku's Simultix14 or an equivalent device can be used. As the analysis surface, a surface with a maximum roughness Rz (JIS-B0601(2013)) of 6.3 μm or less obtained by cutting or mechanical polishing may be used. When sampling a sample for X-ray fluorescence analysis from the molten metal during melting and casting, it should be cast into a shape with a diameter of 30 - 40 mm and a thickness of about 50 - 80 mm, then cut to a thickness of about 10 - 20 mm, and the cut surface shall be used as the analysis surface. The X-ray fluorescence analysis is performed based on JIS K 0119:2008 and measured by the wavelength dispersive method.

[0018] The copper alloy of the present embodiment is not particularly limited, but for example, it can be made into a copper alloy sheet by a manufacturing method including a rolling process as described below. The copper alloy sheet is not particularly limited as long as it has the above composition and is an object having a three-dimensional shape with a predetermined thickness. The "sheet" of this copper alloy sheet includes sheets, strips, and foils. In addition, this copper alloy sheet includes not only the copper alloy sheet before processing for use in electronic components, but also the copper alloy sheet during or after processing. The thickness of the copper alloy sheet is, for example, 0.030 - 1.2 mm. The thickness is preferably 0.050 - 0.60 mm, and more preferably 0.080 - 0.30 mm.

[0019] Since the copper alloy of the present embodiment has the composition as described above, it has high conductivity and strength. Specifically, in the copper alloy sheet manufactured through a rolling process, the tensile strength in the direction parallel to the rolling direction of the copper alloy of the present embodiment can be 870 MPa or more. Since it has such a high tensile strength, for the miniaturized copper alloy parts for electronic components or parts in the copper alloy parts manufactured from the copper alloy, during the manufacturing process of the electronic components, specifically, during the series of processes until the electronic components are manufactured including the process of processing the copper alloy sheet to manufacture the copper alloy parts (for example, lead frames), the deformation that may occur can be suppressed. The tensile strength in the 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. Yes. The upper limit of the tensile strength in the direction parallel to the rolling direction is not particularly limited, and 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 testing machine in accordance with JIS-Z2241 (2011). Specifically, from each sample, a JIS 13B test piece is produced using a press so that the tensile direction is parallel to the rolling direction. The conditions for the tensile test are as follows: the test piece width is 12.5 mm, the measurement temperature is room temperature (15 to 35 °C), the tensile speed is 5 mm / min, and the gauge length is 50 mm. The test is performed with two test pieces, and the average value of the two data can be taken as the tensile strength in the direction parallel to the rolling direction in the present disclosure. The above tensile speed corresponds to the crosshead displacement speed described in the JIS standard. Also, the tensile strength in the direction parallel to the rolling direction can be set within a desired range by setting the composition of the copper alloy to the composition of the copper alloy of the present embodiment described above.

[0021] The copper alloy of the present embodiment may have a conductivity of 30% IACS or more. By having a conductivity of 30% IACS or more, it can be effectively used as a copper alloy component of an electronic component. The conductivity means the conductivity in the direction parallel to the rolling direction. Also, the conductivity can be set within a desired range by setting the composition of the copper alloy to the composition of the copper alloy of the present embodiment described above. The conductivity (EC: %IACS) can be 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 conductivity can be measured at room temperature (25 °C) in the direction parallel to the rolling direction. Note that, due to the convenience of the test sample, the gauge length (distance between electrical resistance measurements) can be measured at 50 mm.

[0022] Hereinafter, a method for manufacturing a copper alloy plate will be described. In this embodiment, the copper alloy plate is not particularly limited, but can be manufactured by a method including a rolling process. Specifically, the copper alloy plate can be manufactured, for example, by performing homogenization, hot rolling, intermediate cold rolling, solution treatment, aging treatment, finish cold rolling, and stress relief annealing on an ingot in this order. Cold rolling before the solution treatment is not essential and may be performed as necessary. Also, cold rolling may be performed as necessary after the solution treatment and before the aging treatment, or the solution treatment and the aging treatment may be performed two or more times each. After performing the above respective steps, grinding, polishing, shot blasting, pickling, etc. for removing the oxide scale on the surface can be appropriately performed.

[0023] An example of a method for manufacturing a copper alloy plate that can be manufactured by a method including a rolling process using the copper alloy of this embodiment will be described in more detail. The method for manufacturing a copper alloy plate can include a step of melting and casting a raw material of a copper alloy having the desired composition described above. In this step, after melting the raw material of the copper alloy by a method similar to a general method for melting a copper alloy, an ingot is manufactured by continuous casting, semi-continuous casting, or the like. For example, first, using an air melting furnace, raw materials such as electrolytic copper, Ni, Co, Si, Cr are melted to obtain a molten metal having the desired composition. Then, this molten metal is poured into a mold of an arbitrary size and cast into an ingot.

[0024] In this embodiment, the method for manufacturing a copper alloy plate can include a step of performing hot rolling on the ingot that has been optionally subjected to homogenization annealing. The hot rolling of the ingot is not particularly limited, but for example, it can be performed in several passes at 500 to 950°C. Note that the total degree of processing in hot rolling is preferably 90% or more.

[0025] The solution heat treatment is a heat treatment that dissolves silicides such as Ni-Si-based compounds, Co-Si-based compounds, and Ni-Co-Si-based compounds in the Cu matrix and simultaneously recrystallizes the Cu matrix. The heat treatment temperature for solution heat treatment is not particularly limited, but can be, for example, 650 to 1000 °C. Also, the heat treatment time can be 1 second to 10 minutes. Specifically, when the solution heat treatment temperature and time are equal to or higher than the lower limit values of the above ranges, even if a large amount of silicides such as Ni-Co-Si-based compounds are contained in the copper alloy, they can be easily dissolved sufficiently in the Cu matrix and can be recrystallized. When the solution heat treatment temperature and time are equal to or lower than the upper limit values of the above ranges, it is easy to suppress the coarsening of the recrystallized grains. The heat treatment temperature is preferably 700 to 950 °C, and the time is preferably 5 seconds to 5 minutes.

[0026] In this embodiment, the method for manufacturing a copper alloy sheet may include a step of performing an aging treatment on the intermediate body after the above solution heat treatment. The heat treatment temperature for the aging treatment is not particularly limited, but can be, for example, 375 to 625 °C. Also, the heat treatment time can be 0.5 to 50 hours. When the aging treatment temperature and time are equal to or higher than the lower limit values of the above ranges, the precipitation amounts of Ni-Si-based compounds, Co-Si-based compounds, and Ni-Co-Si-based compounds tend to be sufficient amounts and sufficient strength is easily obtained. When the aging treatment temperature and time are equal to or lower than the upper limit values of the above ranges, coarsening and re-dissolution of the precipitates can be prevented, and it is easy to sufficiently improve the strength and conductivity. In order to sufficiently increase the strength and conductivity of the copper alloy, it is important to increase the tensile strength and conductivity in the direction parallel to the rolling direction of the intermediate after aging treatment. For example, in order to make the tensile strength of the copper alloy 870 MPa or more, the tensile strength of the intermediate after aging treatment may be 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 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 after aging treatment may be 850 MPa or more. For example, the conductivity in the direction parallel to the rolling direction of the intermediate after aging treatment may be 40% IACS or more. The aging treatment is preferably carried out in an inert atmosphere such as Ar, N2, H2, etc. to suppress the generation of the oxide film.

[0027] In this embodiment, the method for manufacturing a copper alloy sheet may include a step of performing finish cold rolling on the above intermediate. The finish cold rolling is not particularly limited, but for example, it is performed in several passes. It is preferable to perform rolling of 1 pass or more. The total degree of working of the finish cold rolling is preferably 40% or more. By applying processing strain to the material by finish cold rolling, the strength can be improved. The upper limit value of the degree of working of the finish cold rolling is preferably 90% or less. By the degree of working being 90% or less, it is possible to prevent the conductivity from decreasing due to the processing strain of severe working. The degree of working (%) is expressed as working degree (%) = [(TB - TA) / TB] × 100, where TB is the thickness of the processing target to be rolled and TA is the thickness of the processing target after rolling.

[0028] In this embodiment, the method for manufacturing a copper alloy sheet may include a step of performing stress relief annealing on the intermediate after the above finish cold rolling. The stress relief annealing may be performed under general conditions. For example, it can be performed at 250°C to 550°C for a holding time of 5 seconds to 5 hours. The stress relief annealing may be performed in the atmosphere or in an inert atmosphere such as nitrogen or argon gas. Further, 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, after each rolling step and each heat treatment step, pickling, polishing, degreasing, facing, and trimming may be performed as necessary. Also, in this manufacturing method, rolling steps and heat treatment steps other than the above may be included.

[0030] [Electronic component] The electronic component of this embodiment is an electronic component containing the copper alloy of the above-described embodiment. More specifically, the electronic component of this embodiment has inside it a copper alloy component manufactured from the copper alloy of this embodiment via a copper alloy sheet. Examples of the electronic component include semiconductor packages. The miniaturized copper alloy components that can be manufactured from the copper alloy of this embodiment have characteristics in which deformation during the manufacturing process of the electronic component is suppressed, and thus it is preferable to use the copper alloy of this embodiment for manufacturing semiconductor packages that have many miniaturized structures. When the electronic component is a semiconductor package, the semiconductor package is not particularly limited, but for example, a lead frame is manufactured using a copper alloy sheet manufactured from the copper alloy of this embodiment, and then a semiconductor element is supported and fixed on the lead frame, the semiconductor element and the lead are wire-bonded to form internal wiring, and the semiconductor element is sealed with a predetermined resin member, whereby it can be manufactured. As described above, the electronic component of this embodiment may contain the copper alloy of this embodiment.

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

[0032] (Aspect of the present disclosure) The first aspect of the present disclosure is a copper alloy containing 2.3 to 4.6% by mass of Ni, 0.10 to 0.50% by mass of Co, 0.60 to 1.3% by mass of Si, 0.010 to 0.10% by mass of Cr, with the balance being Cu and unavoidable impurities.

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

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

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

[0036] The 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% by mass of Cr.

[0037] The 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% by mass of Ni.

[0038] The seventh aspect of the present disclosure is the copper alloy according to any one of the first to sixth aspects, wherein the mass ratio R A of the total of Ni and Co to Si is 3.5 to 5.0.

[0039] The eighth aspect of the present disclosure is the copper alloy according to the seventh aspect, wherein the ratio R A is 3.5 to 4.5.

[0040] The ninth aspect of the present disclosure is the copper alloy according to any one of the first to eighth aspects, wherein the mass ratio R B of Co to Ni is 0.010 to 0.155.

[0041] The tenth aspect of the present disclosure is the copper alloy according to the ninth aspect, wherein the ratio R B is 0.025 to 0.155.

[0042] The eleventh aspect of the present disclosure is the copper alloy according to the ninth aspect, wherein the ratio R B is 0.056 to 0.086.

[0043] The 12th aspect of the present disclosure is the copper alloy according to any one of the 1st to 11th aspects, 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, Cr, Ag, Zn, Sn, Pb, Zr, Al, As, Se, Te, Sb, Bi, Au, Ti, Nb, V, Ta, W, Mo, and Mn.

[0044] The 13th aspect of the present disclosure is the copper alloy according to any one of the 1st to 12th aspects, having an electrical conductivity of 30% IACS or more.

[0045] The 14th aspect of the present disclosure is the copper alloy according to any one of the 1st to 13th aspects, having a tensile strength in the direction parallel to the rolling direction of 870 MPa or more.

[0046] The 15th aspect of the present disclosure is the copper alloy according to any one of the 1st to 14th aspects, having a tensile strength in the direction parallel to the rolling direction of 930 MPa or more.

[0047] The 16th aspect of the present disclosure is an electronic component including the copper alloy according to any one of the 1st to 15th aspects.

Examples

[0048] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to the following examples at all. In Example 1, a copper alloy plate was produced from the 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 air melting furnace. This ingot was hot-rolled at 950 °C to a plate thickness of 10.0 mm. After hot rolling, facing was performed, and then intermediate cold rolling was performed to a plate thickness of 0.167 mm. Thereafter, solution treatment and aging treatment were performed under the conditions shown in Table 1, respectively. Next, finish cold rolling was performed to a plate thickness of 0.1 mm with the degree of working shown in Table 1 to obtain a copper alloy plate. In Example 2, the cold-rolled copper alloy sheet that had been finish cold-rolled 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 shown in Table 1 were changed. 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 shown in Table 1 was changed and the solution treatment temperature was changed to the temperature conditions of 900°C or 925°C shown in Table 1. For each evaluation of the copper alloy in Comparative Example 1, the numerical values of the evaluation results of the two samples (tensile strength and conductivity for the intermediate after aging treatment and the copper alloy sheet after finish cold rolling as shown in Table 1) were plotted on the vertical axis, and the solution treatment temperature was plotted on the horizontal axis. A straight line connecting the plots was calculated, and then, by substituting the value of the solution treatment temperature of 915°C into the mathematical formula representing the straight line, the estimated evaluation results of the copper alloy and its intermediate when the solution treatment was carried out at 915°C were obtained. In Comparative Example 2, in the same manner as in Comparative Example 1, three samples were produced as copper alloy sheets by the same production method as in Example 1, except that the composition of the copper alloy shown in Table 1 was changed and the solution treatment temperature was changed to the temperature conditions of 910°C, 935°C, and 950°C shown in Table 1. For each evaluation of the copper alloy in Comparative Example 2, the numerical values of the evaluation results of the three samples were plotted on the vertical axis, and the solution treatment temperature was plotted on the horizontal axis. An approximate straight line connecting the plots was calculated (using the approximate straight line function of Microsoft Excel (registered trademark)), and then, by substituting the value of the solution treatment temperature of 915°C into the mathematical formula representing the approximate straight line, the estimated evaluation results of the copper alloy and its intermediate when the solution treatment was carried out at 915°C were obtained.

[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. As the X-ray fluorescence analyzer, Simultix14 manufactured by Rigaku Corporation was used. As the analysis surface, one obtained by cutting or mechanical polishing so that the maximum surface roughness Rz (JIS-B0601 (2013)) was 6.3 μm or less was used. The X-ray fluorescence analysis was performed based on JIS K 0119:2008 and measured by the wavelength dispersive method.

[0051] 〔Tensile strength (TS)〕 For the obtained copper alloy sheet, the tensile strength (TS) was measured in the direction parallel to the rolling direction by a tensile testing machine in accordance with JIS-Z2241 (2011). Specifically, from each sample, a JIS13B test piece was produced using a press machine so that the tensile direction was parallel to the rolling direction. The conditions of the tensile test were: the test piece width was 12.5 mm, the measurement temperature was room temperature (15~35 °C), the tensile speed (crosshead displacement speed) was 5 mm / min, and the gauge length was 50 mm. The test was conducted with 2 test pieces, and the average value of the two data is shown in Tables 1 and 2.

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

[0053]

Table 1

[0054]

Table 2

[0055] As shown in Tables 1 and 2, it was found that by manufacturing with a desired composition, while having a high conductivity, the tensile strength is improved. Therefore, the miniaturized copper alloy parts for electronic components manufactured from the copper alloys of Examples 1 and 2 can suppress deformation in the manufacturing process of the electronic components. The characteristics (tensile strength and conductivity) of the copper alloys of Example 1 and Comparative Examples 1 and 2 were plotted against the Co content (mass %), and the result of drawing a linear approximation curve is shown in FIG. 1. As the Co content increases, Co-Si-based precipitates or Ni-Co-Si-based precipitates are formed, so it is considered that the conductivity is improved. Therefore, a linear approximation curve was created from the experimental values obtained in the examples, and the conductivity at each Co content was predicted. From this result, it can be seen that if the Co content is 0.10 mass % or more, a conductivity of 39.7% IACS or more can be realized. If the Co content is 0.20 mass % or more, it can be seen that a conductivity of 39.8% IACS or more can be realized. If the Co content is 0.25 mass % or more, it can be seen that a conductivity of 39.7% IACS or more can be realized. If the Co content is 0.25 mass % or more, it can be seen that a conductivity of 40.1% IACS or more can be realized. The characteristics (tensile strength and conductivity) of the copper alloys of Example 1 and Comparative Examples 1 and 2 were plotted against the mass ratio R of Co to Ni B and the result of drawing a linear approximation curve is shown in FIG. 3. As R B increases, Co-Si-based precipitates or Ni-Co-Si-based precipitates are formed, so it is considered that the conductivity is easily obtained and the strength is difficult to obtain. Therefore, a linear approximation curve was created from the experimental values obtained in the examples, and the strength and conductivity at each R B were predicted. From this result, it can be seen that if the ratio R B is 0.010 or more, a conductivity of 39.7% IACS or more can be realized. If the ratio R B is 0.025 or more, it can be seen that a conductivity of 39.7% IACS or more can be realized. If the ratio R B is 0.056 or more, it can be seen that a conductivity of 39.8% IACS or more can be realized. Also, if the ratio R B is 0.155 or less, it can be seen that a tensile strength of 938 MPa or more can be realized. If the ratio R BIf it is 0.086 or less, it can be seen that a tensile strength of 949 MPa or more can be achieved.

Industrial Applicability

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

Claims

1. A copper alloy containing 2.3 to 4.6% by mass of Ni, 0.10 to 0.50% by mass of Co, 0.60 to 1.3% by mass of Si, 0.010 to 0.10% by mass of Cr, with the balance being Cu and unavoidable impurities.

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

3. The copper alloy according to claim 2, containing 0.10 to 0.40% by mass of Co.

4. The copper alloy according to claim 3, containing 0.20 to 0.30% by mass of Co.

5. The copper alloy according to claim 1, containing 0.020 to 0.070% by mass of Cr.

6. The copper alloy according to claim 1, containing 3.0 to 4.0% by mass of Ni.

7. The mass ratio R of the total of Ni and Co to Si A is 3.5 to 5.0 for the copper alloy according to claim 1.

8. The ratio R A is 3.5 to 4.5 for the copper alloy according to claim 7.

9. The mass ratio R of Co to Ni B is 0.010 to 0.155 for the copper alloy according to claim 1.

10. The ratio R B is 0.025 to 0.155 for the copper alloy according to claim 9.

11. The ratio R B is 0.056 to 0.086 for the copper alloy according to claim 9.

12. The copper alloy according to claim 1, further containing in total 0.010 to 1.0% by mass 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.

13. The copper alloy according to claim 1, having a conductivity of 30% IACS or more.

14. The copper alloy according to claim 1, having a tensile strength in the direction parallel to the rolling direction of 870 MPa or more.

15. The copper alloy according to claim 1, having a tensile strength in the direction parallel to the rolling direction of 930 MPa or more.

16. An electronic component comprising the copper alloy according to any one of claims 1 to 15.

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