Copper alloy and electronic component

Abstract

The purpose of this invention is to provide a copper alloy with high conductivity and high strength, and electronic components containing the same. The copper alloy of this invention contains 2.3–4.6% by mass of Ni, 0.10–0.50% by mass of Co, 0.60–1.3% by mass of Si, and 0.010–0.10% by mass of Cr, with the remainder consisting of Cu and unavoidable impurities.

Description

Technical Field

[0001] This invention relates to a copper alloy and electronic components. Background Technology

[0002] Cosen alloys are copper alloys in which intermetallic compounds such as Ni-Si, Co-Si, and Ni-Co-Si are precipitated in a Cu matrix, possessing both high strength and high conductivity. Due to these properties, Cosen alloys are used as copper alloy components in electronic parts, for example, in semiconductor packages as lead frames that support and fix semiconductor components and form internal wiring (see, for example, Patent Document 1).

[0003] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2018-035437 Summary of the Invention

[0004] [The problem the invention aims to solve] With the increasing functionality of electronic components in recent years, copper alloy components (or specific parts of copper alloy components) made of Cosun alloys have become increasingly miniaturized. For copper alloys, high conductivity is required, while further improving the characteristics to adapt to this miniaturization.

[0005] For example, in semiconductor packages used as electronic components, the increasing functionality in recent years has led to a miniaturization of the package structure, resulting in larger packages themselves. Consequently, the lead frames made of copper alloys used to construct semiconductor packages, especially the leads within the lead frames, are also becoming increasingly miniaturized. Leads are the internal wiring (pins) within the semiconductor package used to connect to external wiring. This miniaturization results in increased lead lengths or narrower spacing between leads. However, due to this miniaturization, the leads sometimes lack sufficient strength. During the manufacturing steps of the lead frame or semiconductor package (e.g., the step of creating the desired lead frame by semi-etching a copper alloy plate, or the step of wire bonding to connect the leads to the semiconductor component after placing the semiconductor component in the lead frame), the leads sometimes deform and are difficult to maintain their shape with high precision. As a result, it is sometimes impossible to manufacture semiconductor packages efficiently, and for copper alloys, further improvements in strength are required.

[0006] The purpose of this invention is to provide a copper alloy with high conductivity and high strength, and an electronic component containing the same.

[0007] [Technical means to solve the problem] In one embodiment, the copper alloy of the present invention contains 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, and 0.010 to 0.10% by mass of Cr, with the remainder consisting of Cu and unavoidable impurities.

[0008] In one embodiment, the electronic component of the present invention contains the copper alloy described above.

[0009] [The effects of the invention] The present invention provides a copper alloy with high conductivity and high strength, and electronic components containing the same. Attached Figure Description

[0010] [ Figure 1 The graph depicts the properties of the copper alloys of Example 1 and Comparative Examples 1 and 2 relative to the amount of Co (mass%), showing a linear approximate curve. The first axis represents tensile strength, and the second axis represents electrical conductivity. Furthermore, square plots represent tensile strength, and circular plots represent electrical conductivity.

[0011] [ Figure 2 [This refers to the copper alloys of Example 1 and Comparative Examples 1 and 2, relative to the mass ratio R of Co to Ni.] B Their properties are plotted, creating graphs that approximate linear curves. The first axis represents tensile strength, and the second axis represents electrical conductivity. Furthermore, square plots represent tensile strength, and circular plots represent electrical conductivity. Detailed Implementation

[0012] The following describes in detail the embodiments of the present invention (hereinafter also referred to as "the embodiments"), but the present invention is not limited to the following embodiments.

[0013] In this invention, "A~B" means "above A and below B". Here, A and B represent numerical values.

[0014] [Copper Alloy] The copper alloy of this embodiment contains 2.3–4.6% by mass Ni, 0.10–0.50% by mass Co, 0.60–1.3% by mass Si, and 0.010–0.10% by mass Cr, with the remainder consisting of Cu and unavoidable impurities. That is, the copper alloy of this embodiment is a Cu-Ni-Co-Si alloy. Ni, Co, and Si can be precipitated into Ni-Co-Si intermetallic compound particles through appropriate heat treatment, achieving high conductivity and high strength.

[0015] In this embodiment, the copper alloy has a Ni concentration of 2.3–4.6% by mass, a Co concentration of 0.10–0.50% by mass, and a Cr concentration of 0.010–0.10% by mass. This allows the high conductivity of the copper alloy to be maintained while simultaneously increasing its strength.

[0016] The desired strength cannot be obtained when the Ni concentration is less than 2.3% by mass. The desired strength or conductivity cannot be obtained when the Co concentration is less than 0.10% by mass. The desired strength cannot be obtained when the Cr concentration is less than 0.010% by mass.

[0017] At Ni concentrations exceeding 4.6% by mass, while sufficient strength is achieved, conductivity decreases. Furthermore, at Co concentrations exceeding 0.50% by mass, while adequate conductivity is obtained, high strength is difficult to achieve. At Cr concentrations exceeding 0.10% by mass, Cr forms compounds with other components, making it difficult to form the target Ni-Co-Si precipitates. Consequently, the desired strength cannot be obtained.

[0018] The Ni concentration is preferably 2.8–4.4% by mass, more preferably 3.0–4.0% by mass, and even more preferably 3.3–3.7% by mass. Furthermore, the Co concentration is preferably less than 0.50% by mass, more preferably 0.10–0.40% by mass, and even more preferably 0.20–0.30% by mass. The Cr concentration is preferably 0.020–0.070% by mass, more preferably 0.040–0.060% by mass.

[0019] In this embodiment, the Si concentration in the copper alloy is 0.6–1.3% by mass. This maintains the high conductivity of the copper alloy while simultaneously improving its strength. If the Si concentration is less than 0.60% by mass, the desired strength cannot be obtained. Furthermore, if the Si concentration exceeds 1.3% by mass, while sufficient strength can be obtained, conductivity will decrease.

[0020] The Si concentration is preferably 0.7 to 1.2% by mass, more preferably 0.8 to 1.0% by mass.

[0021] As mentioned above, Ni-Co-Si precipitates formed from Ni, Co, and Si are considered to be intermetallic compounds mainly composed of (Ni+Co)Si. However, Ni, Co, and Si in copper alloys may not all become precipitates due to the aging treatment during the manufacturing process of the copper alloy sheet; they may exist to some extent in a solid-dissolved state within the Cu matrix. The solid-dissolved Ni, Co, and Si can slightly increase the strength of the copper alloy sheet, but this effect is smaller compared to the precipitated state, and may also be a major cause of decreased conductivity. Therefore, the Ni, Co, and Si content ratio is preferably close to the composition ratio of (Ni+Co)Si. Therefore, the total mass ratio of Ni and Co to Si, R... A Preferably, it is 3.5 to 5.0, more preferably 3.5 to 4.5.

[0022] As mentioned above, Ni-Co-Si precipitates contribute to improving the strength and conductivity of copper alloys. Ni tends to primarily contribute to increasing the strength of copper alloys, while Co tends to primarily contribute to increasing their conductivity. Therefore, from the viewpoint of maintaining high conductivity while simultaneously improving strength, the mass ratio of Co to Ni, R... B It can be set to 0.010–0.155. This is determined by the mass ratio R of Co to Ni. B A value above 0.010 allows copper alloys to maintain high electrical conductivity. This is achieved through the mass ratio of Co to Ni, R... B A value below 0.155 can effectively improve the strength of copper alloys.

[0023] R B Preferably, it is 0.025 to 0.155, more preferably 0.056 to 0.086.

[0024] In addition to the elements mentioned above, the copper alloy of this embodiment may further contain a total of 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 (hereinafter also referred to as "added elements"). This improves the strength, heat resistance, and stress relaxation resistance of the copper alloy.

[0025] By adding an element in an amount of 0.010% by mass or more, the desired effect described above is readily obtained. Furthermore, by adding an amount of 1.0% by mass or less, the desired properties can be obtained while simultaneously preventing a decrease in conductivity.

[0026] The total amount of added elements is preferably 0.020 to 0.080% by mass, more preferably 0.050 to 0.080% by mass.

[0027] In this embodiment, the remaining portion other than the components described above consists of Cu and unavoidable impurities. Here, unavoidable impurities refer to impurity elements that cannot be avoided from being mixed into the material during the manufacturing process. The concentration of each element that is an unavoidable impurity may be set to, for example, 0.015% by mass or less, preferably 0% (undetectable).

[0028] The composition of copper alloys can also be determined by wet analysis. Ni can be determined using the copper-separated dimethylglyoxime gravimetric method (JIS-H1056 (2003)), and Si can be determined using the silica gravimetric method (JIS-H1061 (2006)). Other additive and impurity elements can be determined using ICP emission spectrometry. The analysis of other additive elements is performed using an internal standard method, with Y (yttrium) as the internal standard. The internal standard can also be any element other than Y. ICP emission spectrometry is performed using an ICP emission spectrometry analyzer (ICP-OES) SPS3100 or equivalent device manufactured by Hitachi Advanced Scientific Corporation. In the case of ICP emission spectrometry, the 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 diluted before use.

[0029] Furthermore, the composition of copper alloys can also be determined using fluorescence X-ray analysis. As the fluorescence X-ray analysis apparatus, Rigaku's Simultix14 or an equivalent apparatus can be used. The analysis surface can be a surface that has been cut or mechanically ground to achieve a maximum surface roughness Rz (JIS-B0601 (2013)) of 6.3 μm or less. In the case of collecting samples for fluorescence X-ray analysis from the molten metal during self-melting casting, after casting into a shape of approximately 30–40 mm Φ and 50–80 mm thickness, the sample is cut into sections approximately 10–20 mm thick, and the cut surface is then used as the analysis surface. Fluorescence X-ray analysis is performed based on JIS K 0119:2008, using a wavelength dispersion method.

[0030] The copper alloy used in this embodiment is not particularly limited, and for example, a copper alloy sheet can be manufactured by a manufacturing method including a rolling step as described below. As a copper alloy sheet, there is no particular limitation as to whether it is an object with a three-dimensional shape composed of the above-described components and having a specified thickness. The term "sheet" in this copper alloy sheet also includes sheets, strips, and foils. Furthermore, this copper alloy sheet includes, for example, not only copper alloy sheets before processing for use in electronic components, but also copper alloy sheets in the process of processing or after processing. The thickness of the copper alloy sheet is, for example, 0.030 to 1.2 mm. This thickness is preferably 0.050 to 0.60 mm, and more preferably 0.080 to 0.30 mm.

[0031] The copper alloy of this embodiment, having the composition described above, possesses high conductivity and strength. Specifically, the tensile strength of the copper alloy sheet manufactured by the rolling process can reach 870 MPa or higher in the direction parallel to the rolling direction. Due to this high tensile strength, deformation that may occur in miniaturized copper alloy components or portions thereof used in electronic components can be suppressed during the manufacturing process of electronic components, specifically including the step of processing copper alloy sheets to manufacture copper alloy components (e.g., lead frames).

[0032] 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.

[0033] There is no particular limit to the upper limit of the tensile strength in the direction parallel to the rolling direction. For example, the tensile strength may be less than 1200 MPa, less than 1100 MPa, or less than 1000 MPa.

[0034] The tensile strength in the direction parallel to the calendering direction can be determined using a tensile testing machine according to JIS-Z2241 (2011). Specifically, JIS 13B test pieces are prepared from each specimen using a pressing machine with the tensile direction parallel to the calendering direction. Regarding the tensile test conditions, the test piece width is set to 12.5 mm, the measurement temperature is set to room temperature (15–35°C), the tensile speed is set to 5 mm / min, and the gauge length is set to 50 mm. Two test pieces can be used for the test, and the average of the two data points is taken as the tensile strength in the direction parallel to the calendering direction in this invention. The aforementioned tensile speed is equivalent to the crosshead displacement speed described in the JIS standard. The tensile testing machine can be the AUTO COM AC-100KN-C manufactured by TSE Co., Ltd., or an equivalent device.

[0035] Furthermore, by setting the composition of the copper alloy to the composition of the copper alloy described in this embodiment, the tensile strength in the direction parallel to the rolling direction can be within the desired range.

[0036] The copper alloy in this embodiment has a conductivity of 30% IACS or higher. With a conductivity of 30% IACS or higher, it can be effectively used as a copper alloy component for electronic parts.

[0037] Conductivity refers to the conductivity in the direction parallel to the rolling direction.

[0038] Furthermore, by setting the composition of the copper alloy to the composition of the copper alloy described in this embodiment, the conductivity can be made to be within the desired range.

[0039] Conductivity (EC: %IACS) can be determined according to JIS-H0505 (1975) using the four-terminal method. A double bridge can be used for the measurement, and resistance can be determined based on the average cross-sectional area method. Regarding conductivity, the conductivity in the direction parallel to the rolling direction can be measured at room temperature (25°C). Furthermore, for the convenience of the test sample, the gauge length (distance between resistance measurements) can be 50 mm.

[0040] The following describes the manufacturing method of copper alloy plates.

[0041] In this embodiment, the copper alloy plate is not particularly limited and can be manufactured by a method including a rolling step. Specifically, the copper alloy plate can be manufactured by sequentially homogenizing, hot rolling, intermediate cold rolling, solution treatment, aging treatment, fine cold rolling, and stress-relief annealing of an ingot. Cold rolling before solution treatment is not necessary and can be implemented as needed. In addition, cold rolling can be performed as needed after solution treatment and before aging treatment, or more than two solution treatments and aging treatments can be performed separately. After performing the above steps, appropriate grinding, polishing, bead blasting, pickling, etc., can be performed to remove the oxide scale on the surface.

[0042] An example of a method for manufacturing a copper alloy sheet that can be manufactured using the copper alloy of this embodiment by means of a rolling step is described in more detail.

[0043] A method for manufacturing copper alloy plates may include a step of first melting and casting a raw material of a copper alloy having the desired composition. In this step, the raw material of the copper alloy is melted using a method similar to that used for melting general copper alloys, and then an ingot is manufactured by continuous casting or semi-continuous casting. For example, firstly, raw materials such as electrolytic copper, Ni, Co, Si, and Cr are melted using an atmospheric melting furnace to obtain a molten liquid with the target composition. Then, the molten liquid is poured into a mold of any size to cast an ingot.

[0044] In this embodiment, the method for manufacturing the copper alloy plate may include a step of hot rolling an ingot that has undergone arbitrary homogenization annealing. The hot rolling of the ingot is not particularly limited; for example, it may be performed in several passes at 500–950°C. Furthermore, the overall machining degree of the hot rolling is preferably set to 90% or more.

[0045] Solution treatment is a heat treatment in which silicides such as Ni-Si, Co-Si, and Ni-Co-Si compounds are dissolved in a Cu matrix, while the Cu matrix is ​​recrystallized. The heat treatment temperature for solution treatment is not particularly limited, but can be set to, for example, 650–1000°C. Furthermore, the heat treatment time can be set to 1 second–10 minutes. Specifically, by setting the solution treatment temperature or time above the lower limit of the above range, even if the copper alloy contains a large amount of silicides such as Ni-Co-Si compounds, they can be easily and fully dissolved in the Cu matrix, and recrystallization can be achieved. By setting the solution treatment temperature or time below the upper limit of the above range, the coarsening of recrystallized grains can be easily suppressed.

[0046] The preferred heating temperature is 700–950°C, and the preferred time is 5 seconds to 5 minutes.

[0047] In this embodiment, the method for manufacturing the copper alloy plate may include an aging treatment step for the intermediate material after the above-mentioned solution treatment. The heating temperature for the aging treatment is not particularly limited, but may be set to, for example, 375–625°C. Furthermore, the heating time may be set to 0.5–50 hours.

[0048] When the aging treatment temperature or time is above the lower limit of the above range, the amount of Ni-Si compounds, Co-Si compounds, and Ni-Co-Si compounds precipitated is sufficient, and there is a tendency to easily obtain sufficient strength. When the aging treatment temperature or time is below the upper limit of the above range, coarsening or resolution of the precipitates can be prevented, and the strength or conductivity can be easily and sufficiently improved.

[0049] To significantly improve the strength and conductivity of copper alloys, it is crucial to enhance the tensile strength and conductivity of the aging-treated intermediate in the direction parallel to the rolling direction. For example, to achieve a tensile strength of 870 MPa or higher for the copper alloy, the tensile strength of the aging-treated intermediate can be increased to 750 MPa or higher. Similarly, to achieve a tensile strength of 930 MPa or higher, the tensile strength of the aging-treated intermediate can be increased to 830 MPa or higher. Furthermore, to achieve a tensile strength of 950 MPa or higher, the tensile strength of the aging-treated intermediate can be increased to 850 MPa or higher. For instance, the conductivity of the aging-treated intermediate in the direction parallel to the rolling direction can be set to 40% IACS or higher.

[0050] To suppress the formation of oxide films, aging treatment is preferably carried out in inactive environments such as Ar, N2, and H2.

[0051] In this embodiment, the method for manufacturing the copper alloy sheet may include a step of fine cold rolling of the aforementioned intermediate material. Fine cold rolling is not particularly limited and may be performed in several passes. Preferably, it is performed in one or more passes. The total machining degree of the fine cold rolling is preferably 40% or more. By imparting processing strain to the material through fine cold rolling, its strength can be improved.

[0052] The upper limit of the machining degree in precision cold rolling is preferably 90% or less. By keeping the machining degree below 90%, it is possible to prevent a decrease in conductivity due to the processing strain caused by intense processing.

[0053] If the thickness of the workpiece used for calendering is set as TB, and the thickness of the workpiece after calendering is set as TA, then the degree of processing (%) is expressed as processing degree (%) = [(TB - TA) / TB] × 100.

[0054] In this embodiment, the method for manufacturing the copper alloy plate may include a stress-relief annealing step for the intermediate material after the aforementioned fine cold rolling. Stress-relief annealing can be performed under normal conditions, for example, at 250°C to 550°C for a holding time of 5 seconds to 5 hours. Stress-relief annealing can be performed in the atmosphere or in an inactive environment such as nitrogen or argon. Furthermore, the stress-relief annealed copper alloy plate can also be cooled by air cooling.

[0055] In this embodiment, the copper alloy plate can be manufactured using a manufacturing method that includes the steps described above. Furthermore, in this manufacturing method, after each rolling step or heat treatment step, pickling, grinding, degreasing, surface cutting (surface trimming), and finishing may also be performed as needed. In addition, this manufacturing method may include rolling steps or heat treatment steps other than those described above.

[0056] [Electronic Components] 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 has a copper alloy component manufactured internally from the copper alloy of this embodiment via a copper alloy plate. For example, a semiconductor package can be used as an electronic component. The miniaturized copper alloy component, which can be manufactured from the copper alloy of this embodiment, has the characteristic of suppressing deformation during the manufacturing process of the electronic component; therefore, the copper alloy of this embodiment is suitable for manufacturing semiconductor packages with more miniaturized structures.

[0057] Furthermore, when the electronic component is a semiconductor package, the semiconductor package is not particularly limited. For example, it can be manufactured by using a copper alloy plate made of the copper alloy of this embodiment to manufacture a lead frame, then supporting and fixing the semiconductor component on the lead frame, wire bonding the semiconductor component and the leads to form internal wiring, and then sealing the semiconductor component with a specified resin component. As described above, the electronic component of this embodiment may also contain the copper alloy of this embodiment.

[0058] While the above describes the embodiments of the present invention, the copper alloy and electronic components of the present invention are not limited to the above examples and can be appropriately modified.

[0059] (Example of the present invention) The first example of the present invention 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 remainder consisting of Cu and unavoidable impurities.

[0060] The second example of the present invention is a copper alloy as described in the first example, which contains less than 0.50% by mass of Co.

[0061] The third example of the present invention is a copper alloy as described in the first or second example, containing 0.10 to 0.40% by mass of Co.

[0062] The fourth example of the present invention is a copper alloy as described in any one of the first to third examples, containing 0.20 to 0.30% by mass of Co.

[0063] The fifth example of the present invention is a copper alloy as described in any one of the first to fourth examples, containing 0.020 to 0.070% by mass of Cr.

[0064] The sixth example of the present invention is a copper alloy as described in any one of the first to fifth examples, containing 3.0 to 4.0% by mass of Ni.

[0065] The seventh example of the present invention is a copper alloy as described in any one of the first to sixth examples, wherein the total mass ratio of Ni and Co to Si is R. A It ranges from 3.5 to 5.0.

[0066] The eighth example of the present invention is a copper alloy as described in the seventh example, wherein the ratio R A It ranges from 3.5 to 4.5.

[0067] The ninth example of the present invention is a copper alloy as described in any one of the first to eighth examples, wherein the mass ratio of Co to Ni is RB The range is 0.010 to 0.155.

[0068] The tenth example of the present invention is a copper alloy as described in the ninth example, wherein the ratio R B The value ranges from 0.025 to 0.155.

[0069] The 11th example of the present invention is a copper alloy as described in the 9th example, wherein the ratio R B The value ranges from 0.056 to 0.086.

[0070] The 12th example of the present invention is a copper alloy as described in any one of the 1st to 11th examples, which further contains a total of 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.

[0071] The 13th example of the present invention is a copper alloy as described in any one of the 1st to 12th examples, having a conductivity of 30% IACS or higher.

[0072] The 14th example of the present invention is a copper alloy as described in any one of the 1st to 13th examples, having a tensile strength of 870 MPa or more in a direction parallel to the rolling direction.

[0073] The 15th example of the present invention is a copper alloy as described in any one of the 1st to 14th examples, having a tensile strength of 930 MPa or more in a direction parallel to the rolling direction.

[0074] The 16th example of the present invention is an electronic component comprising a copper alloy as described in any one of the 1st to 15th examples.

[0075] [Example] The present invention will be further described in detail below through embodiments, but the present invention is not limited to any of the embodiments described below.

[0076] In Example 1, a copper alloy plate is made from the desired copper alloy in the following manner.

[0077] Using electrolytic copper as raw material, the copper alloy with the composition shown in Table 1 was melted and cast in an atmospheric melting furnace. The ingot was hot-rolled at 950°C until the thickness reached 10.0 mm. After hot rolling, face cutting was performed, followed by intermediate cold rolling until the thickness reached 0.167 mm. Then, solution treatment and aging treatment were performed under the conditions shown in Table 1.

[0078] Next, the copper alloy plate is cold rolled to the degree of processing shown in Table 1 until the plate thickness is 0.1 mm.

[0079] Furthermore, in Example 2, the copper alloy sheet from Example 1, which had undergone fine cold rolling, was then subjected to stress-relief annealing in the atmosphere under the conditions shown in Table 2. The stress-relief annealed copper alloy sheet was cooled by air cooling, thereby obtaining the copper alloy sheet of Example 2.

[0080] In Comparative Examples 1 and 2, copper alloy plates were manufactured in the same manner as in Example 1, except that the composition of the copper alloy or the solution treatment conditions were changed to those shown in Table 1. Specifically, in 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 900°C or 925°C as shown in Table 1. Otherwise, two samples as copper alloy plates were manufactured using the same manufacturing method as in Example 1. Then, the evaluation of the copper alloy of Comparative Example 1 was performed by plotting the numerical values ​​of the evaluation results of the two samples (as shown in Table 1, the tensile strength or conductivity of the copper alloy plate after aging treatment or fine cold rolling) on ​​the vertical axis and the solution treatment temperature on the horizontal axis. The straight line connecting the plot was calculated and determined. Then, the value of the solution treatment temperature of 915°C was substituted into the formula representing the straight line to obtain the estimated evaluation results of the copper alloy and its intermediates manufactured by solution treatment at 915°C.

[0081] Furthermore, 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 temperatures were changed to 910°C, 935°C, and 950°C as shown in Table 1. Apart from this, three samples as copper alloy plates were manufactured using the same manufacturing method as in Example 1. Then, the evaluations of the copper alloys in Comparative Example 2 were plotted with the evaluation results of the three samples on the vertical axis and the solution treatment temperature on the horizontal axis. An approximate straight line connecting this plot was calculated and determined (using the approximate straight line function of Microsoft Excel). Then, the value of the solution treatment temperature of 915°C was substituted into the formula representing this approximate straight line, thereby obtaining the estimated evaluation results of the copper alloy and its intermediates manufactured under the condition of solution treatment at 915°C.

[0082] The copper alloy plates of Examples 1 and 2 and the copper alloy plates of Comparative Examples 1 and 2 were subjected to the following measurements. The results are shown in Tables 1 and 2.

[0083] [composition] The composition of the obtained copper alloy was confirmed by fluorescence X-ray analysis. A Rigaku Simultix14 fluorescence X-ray analyzer was used. The analysis surfaces were machined or mechanically ground to achieve a maximum surface roughness Rz (JIS-B0601 (2013)) of 6.3 μm or less. Fluorescence X-ray analysis was performed based on JIS K0119:2008, using a wavelength dispersion method.

[0084] [Tensile Strength (TS)] For the obtained copper alloy plate, the tensile strength (TS) was determined by a tensile testing machine in the direction parallel to the rolling direction, according to JIS-Z2241 (2011).

[0085] Specifically, JIS 13B test pieces were prepared from each specimen using a pressing machine, with the stretching direction parallel to the rolling direction. Regarding the tensile test conditions, the test piece width was set to 12.5 mm, the measurement temperature to room temperature (15–35°C), the tensile speed (crosshead displacement speed) to 5 mm / min, and the gauge length to 50 mm. The test was conducted with two test pieces, and the average values ​​of the two data points are shown in Tables 1 and 2.

[0086] [Conductivity] Conductivity (EC: %IACS) was measured according to JIS-H0505 (1975) using the four-terminal method. A double bridge was used for the measurement, and resistance was measured based on the average cross-sectional area method. Conductivity was measured at room temperature (25°C) in a direction parallel to the rolling direction. Furthermore, the gauge length (distance between resistance measurements) was measured at 50 mm.

[0087] [Table 1] [Table 2] As shown in Tables 1 and 2, it can be seen that by manufacturing with the desired composition, high conductivity is achieved while tensile strength is simultaneously increased. Therefore, the miniaturized copper alloy components for electronic parts manufactured from the copper alloys of Examples 1 and 2 can suppress deformation during the manufacturing process of electronic parts.

[0088] The properties (tensile strength and electrical conductivity) of the copper alloys of Example 1, Comparative Examples 1 and 2 were plotted against the amount of Co (mass%), and the results showing a linear approximate curve are presented below. Figure 1As the Co content increases, Co-Si or Ni-Co-Si precipitates are formed, thus increasing conductivity. Therefore, a linear approximation curve was constructed based on the experimental values ​​obtained in the examples to predict the conductivity at various Co contents. According to the results, a conductivity of 39.7% IACS or higher can be achieved with a Co content of 0.10% by mass or higher. A conductivity of 39.8% IACS or higher can be achieved with a Co content of 0.20% by mass or higher. A conductivity of 40.1% IACS or higher can be achieved with a Co content of 0.25% by mass or higher.

[0089] The properties (tensile strength and electrical conductivity) of the copper alloys of Example 1, Comparative Examples 1 and 2 are compared with the mass ratio R of Co to Ni. B A plot of the Co / Ni (mass ratio) is created, and the result, showing a linear approximate curve, is presented below. Figure 2 With R B The increase in conductivity leads to the formation of Co-Si or Ni-Co-Si precipitates, thus making it easier to obtain conductivity but difficult to obtain strength. Therefore, linear approximate curves are constructed from the experimental values ​​obtained in the examples to predict each R. B The strength and conductivity under the given conditions. Based on this result, it can be concluded that if the strength is greater than R... B With a value above 0.010, a conductivity of over 39.7% IACS can be achieved. It can be seen that if R... B With a value above 0.025, a conductivity of over 39.7% IACS can be achieved. It can be seen that if R... B With a value above 0.056, a conductivity of over 39.8% IACS can be achieved. Furthermore, it is known that if R... B With a value below 0.155, a tensile strength of over 938 MPa can be achieved. It can be seen that if R... B If the value is below 0.086, a tensile strength of over 949 MPa can be achieved.

[0090] [Industry availability] According to the present invention, a copper alloy with high conductivity and high strength and an electronic component containing the same can be provided.

Claims

1. A copper alloy comprising 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 remainder consisting of Cu and unavoidable impurities.

2. The copper alloy as described in claim 1, wherein it contains less than 0.50% by mass of Co.

3. The copper alloy as described in claim 2, wherein it contains 0.10 to 0.40% by mass of Co.

4. The copper alloy as described in claim 3, wherein it contains 0.20 to 0.30% by mass of Co.

5. The copper alloy as described in claim 1, wherein it contains 0.020 to 0.070% by mass of Cr.

6. The copper alloy as described in claim 1, wherein it contains 3.0 to 4.0% by mass of Ni.

7. The copper alloy as described in claim 1, wherein, The combined mass ratio of Ni and Co to Si, R A It ranges from 3.5 to 5.

0.

8. The copper alloy as described in claim 7, wherein, The ratio R A It ranges from 3.5 to 4.

5.

9. The copper alloy as described in claim 1, wherein, The mass ratio of Co to Ni R B The range is 0.010 to 0.

155.

10. The copper alloy as claimed in claim 9, wherein, The ratio R B The value ranges from 0.025 to 0.

155.

11. The copper alloy as claimed in claim 9, wherein, The ratio R B The value ranges from 0.056 to 0.

086.

12. The copper alloy of claim 1, further comprising a total of 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 as described in claim 1, wherein the conductivity is above 30% IACS.

14. The copper alloy as claimed in claim 1, wherein the tensile strength in the direction parallel to the rolling direction is 870 MPa or more.

15. The copper alloy as claimed in claim 1, wherein the tensile strength in the direction parallel to the rolling direction is 930 MPa or higher.

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

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