Copper alloy sheet, electronic component, and method for producing copper alloy sheet

Abstract

The purpose of the present disclosure is to provide a copper alloy sheet having high strength. A copper alloy sheet according to the present disclosure contains 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, and 0.10 to 1.3 mass% Si, the balance being Cu and inevitable impurities, and has a tensile strength in the direction perpendicular to the rolling direction of 930 MPa or greater.

Description

Copper alloy sheet, electronic component, and method for manufacturing copper alloy sheet

[0001] The present invention relates to a copper alloy sheet, an electronic component, and a method for manufacturing a copper alloy sheet.

[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) manufactured from Corson alloy copper alloy sheets to be included in electronic components have become increasingly miniaturized. This has led to demands for copper alloy sheets that maintain high electrical conductivity while also improving their properties to accommodate this miniaturization. For example, in the case of semiconductor packages, which are electronic components, the recent trend toward increasingly sophisticated functionality has led to increasingly compact semiconductor package structures and even larger packages. Therefore, efforts are being made to miniaturize lead frames manufactured from copper alloy sheets 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 alloy plates is required.

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

[0006] The present inventors have conducted extensive research to solve the problems of the prior art, and as a result have reached the following findings. The finely divided copper alloy components in electronic components extend in various directions relative to the rolling direction of the copper alloy sheet used to manufacture them. Therefore, in order to effectively suppress deformation of the finely divided copper alloy components, it is essential that the copper alloy sheet has high strength in various directions relative to the rolling direction. Based on this finding, the present inventors have conducted further research and found that a copper alloy sheet containing predetermined amounts of Ni, Co, and Si and having high tensile strength in a predetermined direction relative to the rolling direction can solve the above problems. Specifically, the copper alloy sheet of the present disclosure is as follows.

[0007] In one embodiment, the copper alloy sheet of the present disclosure contains 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the balance being Cu and unavoidable impurities. The tensile strength in a direction perpendicular to the rolling direction is 930 MPa or more.

[0008] In another embodiment, the copper alloy sheet of the present disclosure contains 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the balance being Cu and unavoidable impurities. The tensile strength in a direction inclined at 45° to the rolling direction is 885 MPa or more.

[0009] In yet another embodiment, the copper alloy sheet of the present disclosure contains 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the balance being Cu and unavoidable impurities. The tensile strength in a direction inclined at 22.5° to the rolling direction is 880 MPa or more.

[0010] In one embodiment, the electronic component of the present disclosure is an electronic component containing the copper alloy of the present disclosure.

[0011] In one embodiment, a method for producing a copper alloy sheet according to the present disclosure includes the steps of: hot-rolling an ingot of a copper alloy containing 1.5 to 4.6% by mass of Ni, 0.10 to 0.80% by mass of Co, 0.10 to 1.3% by mass of Si, with the balance being Cu and unavoidable impurities; solution-treating the obtained copper alloy intermediate; aging-treating the copper alloy intermediate; and finish-cold-rolling the copper alloy intermediate, in this order; wherein when the formula (X = (A × B) / (C)) is expressed using the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), and tensile strength (C (MPa)) of the copper alloy intermediate after the solution-treating step, the value of X in the formula is 17.5 or less.

[0012] The present disclosure can provide a copper alloy sheet having high strength, an electronic component including the same, and a method for manufacturing the copper alloy sheet.

[0013] FIG. 1 is a graph summarizing the relationship between a parameter X, which is expressed by the formula (X=(A×B) / (C) (1)), using the electrical conductivity (A), 0.2% proof stress (B), and tensile strength (C) of an intermediate copper alloy sheet after solution treatment, and the tensile strength of the copper alloy sheet (e.g., after stress relief annealing) in a direction parallel to the rolling direction.

[0014] Hereinafter, embodiments of the present disclosure will be described in detail, but the present invention is not limited to the following embodiments. 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.

[0015] [Copper Alloy Sheet] [First Embodiment] The copper alloy sheet of the first embodiment is a copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the remainder being Cu and unavoidable impurities. That is, the copper alloy sheet of this embodiment is a Cu-Ni-Co-Si alloy. By performing an appropriate heat treatment, Ni, Co, and Si form precipitated particles of a Ni-Co-Si intermetallic compound, which can achieve high electrical conductivity and high strength.

[0016] In the composition of the copper alloy sheet of the first embodiment, the Ni concentration is 1.5 to 4.6 mass%, and the Co concentration is 0.10 to 0.80 mass%. This allows the strength of the copper alloy sheet to be further improved while maintaining high electrical conductivity. If the Ni concentration is less than 1.5 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 Ni concentration exceeds 4.6 mass% or the Co concentration exceeds 0.80 mass%, sufficient strength is obtained, but electrical conductivity is reduced. The Ni concentration is preferably 2.0 to 4.6 mass%, preferably 2.3 to 4.6 mass%, and more preferably 3.0 to 4.3 mass%. The Co concentration is preferably 0.10 to 0.80 mass%, preferably 0.13 to 0.60 mass%, and more preferably 0.18 to 0.50 mass%.

[0017] In the composition of the copper alloy sheet of the first embodiment, the Si concentration is 0.10 to 1.3 mass%. This allows the strength of the copper alloy sheet to be further improved while maintaining high electrical conductivity. If the Si concentration is less than 0.10 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 0.30 to 1.3 mass%, more preferably 0.60 to 1.3 mass%, and even more preferably 0.60 to 1.0 mass%.

[0018] 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 through 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 electrical conductivity. Therefore, it is preferable that the content ratio of Ni, Co, and Si be close to the composition ratio of (Ni + Co)Si. Therefore, the mass ratio of the total of Ni and Co to Si is preferably 3.4 to 5.4, more preferably 3.8 to 5.0.

[0019] In the composition of the copper alloy sheet of the first embodiment, in addition to 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") may be further contained in a total amount of 0.010 to 5.0 mass%. This can improve the strength, heat resistance, stress relaxation resistance, etc. of the copper alloy sheet. The additive element may be Cr. 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 5.0 mass% or less, it is possible to prevent a decrease in conductivity while obtaining the desired properties. The total amount of additive elements is preferably 0.030 to 4.0 mass%, more preferably 0.050 to 3.0 mass%.

[0020] In the first 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, and preferably 0% (undetectable). The composition of the copper alloy can also be measured by wet analysis. The copper separation dimethylglyoxime gravimetric method (JIS-H1056 (2003)) may be used for Ni, and the silicon dioxide gravimetric method (JIS-H1061 (2006)) may be used for Si. Other additive elements and impurity elements may be analyzed by ICP atomic emission spectroscopy, and the analysis of other additive elements is performed using an internal standard method, with Y (yttrium) used as the internal standard substance. An element other than Y may be selected as the internal standard substance. ICP optical emission spectroscopy is performed using an ICP optical emission spectroscopy analyzer (ICP-OES) SPS3100 manufactured by Hitachi High-Tech Science Corporation or an equivalent device. In the case of ICP optical 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 may be a Simultix 14 manufactured by Rigaku Corporation or an equivalent device. The analysis surface may be machined or mechanically polished to a maximum surface roughness Rz (JIS-B0601 (2013)) of 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. The X-ray fluorescence analysis is carried out based on JIS K 0119:2008, and the measurement is carried out by a wavelength dispersive method.

[0021] The copper alloy sheet of the first embodiment is not particularly limited as long as it has the above-described composition and is an object having a three-dimensional shape with a predetermined thickness. The "sheet" of the copper alloy sheet of the first embodiment also includes a sheet, a strip, and a foil. Furthermore, the copper alloy sheet of the first embodiment includes not only a copper alloy sheet before processing for use in, for example, electronic components, but also a copper alloy sheet during or after processing. The thickness of the copper alloy sheet of the first embodiment is, for example, 0.03 to 1.2 mm. The thickness is preferably 0.03 to 0.60 mm, and more preferably 0.08 to 0.30 mm.

[0022] The copper alloy sheet of the first embodiment has a tensile strength of 930 MPa or more in a direction perpendicular to the rolling direction. Although the tensile strength of a copper alloy sheet may vary depending on the direction of measurement, the copper alloy sheet of the first embodiment has high tensile strength in a direction perpendicular to the rolling direction. Having a tensile strength of 930 MPa or more in the perpendicular direction can suppress deformation of a miniaturized copper alloy component for an electronic component manufactured from the copper alloy sheet, or a portion of the copper alloy component, during the manufacturing process of the electronic component. Specifically, a deformable copper alloy component or a portion thereof can extend in various directions relative to the rolling direction of the copper alloy sheet before processing. Since the copper alloy sheet of the first embodiment has high tensile strength in a direction perpendicular to the rolling direction, deformation that may occur during the manufacturing process of an electronic component, specifically during a series of processes leading up to the manufacture of the electronic component, including the process of processing the copper alloy sheet to manufacture a copper alloy component (e.g., a lead frame), can be suppressed. The tensile strength in a direction perpendicular to the rolling direction is preferably 1000 MPa or more. The upper limit of the tensile strength in the direction perpendicular to the rolling direction is not particularly limited, but the tensile strength may be, for example, 1200 MPa or less, or 1100 MPa or less. The tensile strength in each direction, including the direction perpendicular to the rolling direction, can be measured by the method described in the Examples section below. As a tensile tester used for the tensile test, an Autocom AC-100KN-C manufactured by TSE Co., Ltd. or an equivalent device can be used. Furthermore, the tensile strength in each direction can be adjusted to a desired range by using the composition of the copper alloy sheet of the first embodiment described above and manufacturing it by the manufacturing method described below. The tensile strength value in each direction can be increased by, for example, adjusting the parameter X in the manufacturing method described below to a small value.

[0023] The copper alloy sheet of the first embodiment may have a tensile strength of 870 MPa or more in a direction parallel to the rolling direction. By having such a high tensile strength in a direction parallel to the rolling direction, deformation of the copper alloy sheet during the manufacturing process of electronic components can be more effectively suppressed. The tensile strength in a direction parallel to the rolling direction is preferably 900 MPa or more. There is no particular limitation on the upper limit of the tensile strength in a direction parallel to the rolling direction, but the tensile strength may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0024] In the copper alloy sheet of the first embodiment, the tensile strength in a direction inclined at 45° to the rolling direction may be 885 MPa or more. By having such a high tensile strength in a direction inclined at 45° to the rolling direction, deformation of the copper alloy sheet during the manufacturing process of electronic components can be more effectively suppressed. The tensile strength in a direction inclined at 45° to the rolling direction is preferably 900 MPa or more. There is no particular upper limit to the tensile strength in a direction inclined at 45° to the rolling direction, but the tensile strength may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0025] In the copper alloy sheet of the first embodiment, the tensile strength in a direction inclined at 22.5° with respect to the rolling direction may be 880 MPa or more. By having such a high tensile strength in a direction inclined at 22.5° with respect to the rolling direction, deformation of the copper alloy sheet during the manufacturing process of electronic components can be more effectively suppressed. The tensile strength in a direction inclined at 22.5° with respect to the rolling direction is preferably 900 MPa or more. There is no particular upper limit to the tensile strength in a direction inclined at 22.5° with respect to the rolling direction, but the tensile strength may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0026] In the copper alloy sheet of the first embodiment, the 0.2% proof stress in the direction perpendicular to the rolling direction may be 895 MPa or more. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacturing process of electronic components. The 0.2% proof stress in the direction perpendicular to the rolling direction is preferably 920 MPa or more. The upper limit of the 0.2% proof stress in the direction perpendicular to the rolling direction is not particularly limited, but the 0.2% proof stress may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less. The 0.2% proof stress in each direction, including the direction perpendicular to the rolling direction, can be measured by the method described in the Examples section below. As a tensile tester used for the tensile test, an Autocom AC-100KN-C manufactured by TSE Co., Ltd. or an equivalent device can be used. The 0.2% proof stress in each direction can be set to a desired range by using the composition of the copper alloy sheet as the composition of the copper alloy sheet of the first embodiment described above and manufacturing it by the manufacturing method described later. The value of the 0.2% proof stress in each direction can be increased by adjusting the parameter X in the manufacturing method described later to a smaller value, for example.

[0027] In the copper alloy sheet of the first embodiment, the 0.2% proof stress in a direction parallel to the rolling direction may be 845 MPa or more. This makes it possible to more effectively suppress deformation of a refined copper alloy part for an electronic component manufactured from the copper alloy sheet, or a portion of the copper alloy part, during the manufacturing process of the electronic component. The 0.2% proof stress in a direction parallel to the rolling direction is preferably 860 MPa or more. The upper limit of the 0.2% proof stress in a direction parallel to the rolling direction is not particularly limited, but the 0.2% proof stress may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0028] In the copper alloy sheet of the first embodiment, the 0.2% proof stress in a direction inclined at 45° to the rolling direction may be 845 MPa or more. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacturing process of electronic components. The 0.2% proof stress in a direction inclined at 45° to the rolling direction is preferably 860 MPa or more. There is no particular limitation on the upper limit of the 0.2% proof stress in a direction inclined at 45° to the rolling direction, but the 0.2% proof stress may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0029] In the copper alloy sheet of the first embodiment, the 0.2% proof stress in a direction inclined at 22.5° with respect to the rolling direction may be 845 MPa or more. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacturing process of electronic components. The 0.2% proof stress in a direction inclined at 22.5° with respect to the rolling direction is preferably 860 MPa or more. There is no particular limitation on the upper limit of the 0.2% proof stress in a direction inclined at 22.5° with respect to the rolling direction, but the 0.2% proof stress may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0030] The copper alloy sheet of the first embodiment may have an electrical conductivity of 35% IACS or more in a direction parallel to the rolling direction. A conductivity of 35% IACS or more allows the copper alloy sheet to be effectively used as a copper alloy component for electronic devices. The electrical conductivity of 37% IACS or more in a direction parallel to the rolling direction is more preferably 37% IACS or more. The electrical conductivity can be adjusted to a desired range by using the composition of the copper alloy sheet of the first embodiment described above and manufacturing the copper alloy sheet by the manufacturing method described below. 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 in a direction parallel to the rolling direction can be measured at room temperature (25°C). The measurement can be performed with a gauge length (electrical resistance measurement distance) of 50 mm.

[0031] The method for producing a copper alloy sheet of this embodiment will be described below. The method for producing a copper alloy sheet of this embodiment includes, in this order, the steps of hot-rolling an ingot of a copper alloy containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the balance being Cu and inevitable impurities, solution-treating the resulting copper alloy intermediate, aging the copper alloy intermediate, and finish-cold-rolling the copper alloy intermediate. Furthermore, when the formula (X = (A × B) / (C)) is expressed using the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), and tensile strength (C (MPa)) of the copper alloy intermediate after the solution-treating step, the value of X in the formula is 17.5 or less. In the method for producing a copper alloy sheet of this embodiment, cold rolling may be performed before the solution treatment, or after the solution treatment and before the aging treatment, or the solution treatment and the aging treatment may each be performed two or more times. Furthermore, in the method for producing a copper alloy sheet of this embodiment, stress relief annealing may be performed after the finish cold rolling. After performing each of the above steps, grinding, polishing, shot blasting, pickling, etc. may be performed as appropriate to remove oxide scale from the surface.

[0032] The method for producing the copper alloy sheet of this embodiment is not particularly limited, but more specifically, it can be produced by the following method. The method for producing the copper alloy sheet of this embodiment 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 or semi-continuous casting. For example, first, raw materials such as electrolytic copper, Ni, Co, and Si are melted using an atmospheric melting furnace to obtain a molten metal with the desired composition. This molten metal is then poured into a mold of any desired size and cast into an ingot. The method for producing the copper alloy sheet of this embodiment may also include a step of hot rolling the ingot, which has been optionally subjected to homogenization annealing. The hot rolling of the ingot is not particularly limited, but can be performed in several passes at, for example, 950°C to 500°C. Note that the total reduction rate of the hot rolling is preferably 90% or more. The degree of reduction (%) is expressed as follows: where TB is the thickness of the workpiece to be rolled and TA is the thickness of the workpiece after rolling.

[0033] Solution treatment is a heat treatment that dissolves silicides (silicides) such as Ni—Si compounds, Co—Si compounds, and Cr—Si compounds in a Cu matrix and simultaneously recrystallizes the Cu matrix. Hot rolling can also serve as solution treatment. FIG. 1 is a graph showing the relationship between a parameter X, expressed by the formula (X = (A × B) / (C) ... (1)), using the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), and tensile strength (C (MPa)) of a copper alloy intermediate after solution treatment, and the tensile strength (MPa) of a copper alloy sheet (e.g., after stress relief annealing) in a direction parallel to the rolling direction. (Note that electrical conductivity (A), 0.2% proof stress (B), and tensile strength (C) are all values ​​obtained by measurement in a direction parallel to the rolling direction.) Setting the value of parameter X to 17.5 or less facilitates the production of the copper alloy sheet of the present disclosure. The heat treatment temperature for the solution treatment can be appropriately selected from the range of, for example, 800 to 1000°C. The heat treatment time can be appropriately selected from the range of 1 second to 1 minute. The value of parameter X can be reduced by relatively increasing the heat treatment temperature for the solution treatment and relatively increasing the heat treatment time. By setting the value of parameter X to 17.5 or less and appropriately selecting and combining the heat treatment temperature and heat treatment time for the solution treatment, it is possible to dissolve the Ni-Co-Si compound in the Cu matrix and simultaneously recrystallize the Cu matrix, thereby precipitating precipitates that contribute to strength during aging treatment and increasing the tensile strength after stress relief annealing. Furthermore, since anisotropy is eliminated by the recrystallization of the metal structure associated with the solution treatment, by setting the value of parameter X to 17.5 or less, similarly high strength can be obtained in directions other than those parallel to the rolling direction (directions inclined at 22.5° and 45° to the rolling direction, and directions perpendicular to the rolling direction). The heat treatment temperature is preferably 850 to 975° C., and the heat treatment time is preferably 5 to 30 seconds.

[0034] The electrical conductivity (A (% IACS)), 0.2% yield strength (B (MPa)), and tensile strength (C (MPa)) of the copper alloy intermediate after the solution treatment in the above formula (1) can be measured by the method described in the section of Examples below.

[0035] The method for producing a copper alloy sheet according to this embodiment 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, preferably 400 to 550°C. The heat treatment time may be 1 to 50 hours, preferably 1.5 to 25 hours. By setting the aging temperature and time at or above the lower limit of the above range, the amount of precipitated Ni-Co-Si compounds tends to be sufficient, making it easier to obtain sufficient strength. By setting the aging temperature and time at or below the upper limit of the above range, coarsening of precipitates and re-dissolution can be prevented, making it easier to sufficiently improve strength and electrical conductivity. To sufficiently increase the strength and electrical conductivity of the copper alloy sheet, the tensile strength of the intermediate body after the aging treatment in a direction parallel to the rolling direction may be 800 MPa or more. Furthermore, the electrical conductivity of the intermediate body after the aging treatment in a direction parallel to the rolling direction may be 40% IACS or more. The aging treatment is preferably carried out in an inert atmosphere such as Ar, N2, or H2 in order to prevent the formation of an oxide film.

[0036] The method for producing a copper alloy sheet according to this embodiment 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. One or more passes of rolling are preferred. The total reduction ratio of the finish cold rolling is preferably 40% or more. Finish cold rolling imparts processing strain to the material, improving its strength. In particular, the strength in a direction inclined relative to the rolling direction is more likely to be improved by increasing the total reduction ratio of the finish cold rolling, the greater the inclination angle. Therefore, by setting the reduction ratio to 40% or more, strength can be improved in various directions relative to the rolling direction. The reduction ratio of the finish cold rolling is more preferably 55% or more, which tends to facilitate sufficient improvement of strength. The upper limit of the reduction ratio of the finish cold rolling is preferably 90% or less. Setting the reduction ratio to 90% or less can prevent electrical conductivity from decreasing due to processing strain caused by heavy processing.

[0037] The method for producing a copper alloy sheet according to this embodiment may include a step of performing stress relief annealing on the intermediate sheet after the above-described finish cold rolling. The stress relief annealing may be performed under general conditions, for example, at 300 to 550°C and a holding time of 5 to 900 seconds. The stress relief annealing may be performed in air or in an inert atmosphere such as nitrogen or argon gas. The copper alloy sheet after stress relief annealing may be cooled by air cooling.

[0038] The copper alloy sheet of the first embodiment can be manufactured by the manufacturing method of the copper alloy sheet of the present embodiment, which includes the above-mentioned 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.

[0039] [Second and Third Embodiments] Next, copper alloy sheets of the second and third embodiments will be described. Note that the description of the configurations that overlap between the copper alloy sheets of the second and third embodiments and the copper alloy sheet of the first embodiment will be omitted as appropriate. The copper alloy sheets of the second and third embodiments are copper alloy sheets containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the remainder consisting of Cu and inevitable impurities. This allows the strength of the copper alloy sheet to be further improved while maintaining the high electrical conductivity of the copper alloy sheet.

[0040] In the compositions of the copper alloy sheets of the second and third embodiments, in addition to the above elements, one or more additive 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 may be further contained in a total amount of 0.010 to 5.0 mass%. This can improve the strength, heat resistance, stress relaxation resistance, etc. of the copper alloy sheet. The additive element may be Cr. 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 5.0 mass% or less, it is possible to prevent a decrease in conductivity while obtaining the desired properties. The total amount of additive elements is preferably 0.030 to 4.0 mass%, more preferably 0.050 to 3.0 mass%.

[0041] The Ni concentration is preferably 2.0 to 4.3 mass%, more preferably 3.0 to 4.3 mass%, the Co concentration is preferably 0.13 to 0.60 mass%, more preferably 0.18 to 0.50 mass%, and the Si concentration is preferably 0.3 to 1.1 mass%, more preferably 0.6 to 1.0 mass%.

[0042] In the copper alloy sheet of the second embodiment, the tensile strength in a direction inclined at 45° to the rolling direction is 885 MPa or more. This makes it possible to suppress deformation of the copper alloy sheet during the manufacturing process of electronic components. The tensile strength in a direction inclined at 45° to the rolling direction is preferably 900 MPa or more. There is no particular upper limit to the tensile strength in a direction inclined at 45° to the rolling direction, but the tensile strength may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0043] In the copper alloy sheet of the third embodiment, the tensile strength in a direction inclined at 22.5° to the rolling direction is 880 MPa or more. This makes it possible to suppress deformation of the copper alloy sheet during the manufacturing process of electronic components. The tensile strength in a direction inclined at 22.5° to the rolling direction is preferably 900 MPa or more. There is no particular upper limit to the tensile strength in a direction inclined at 22.5° to the rolling direction, but the tensile strength may be, for example, 1200 MPa or less, 1100 MPa or less, or 1000 MPa or less.

[0044] In the copper alloy sheets of the second and third embodiments, the tensile strength in a direction perpendicular to the rolling direction, a direction parallel to the rolling direction, a direction inclined at 45° to the rolling direction, and a direction inclined at 22.5° to the rolling direction can be made similar to that of the copper alloy sheet of the first embodiment. Furthermore, in the copper alloy sheets of the second and third embodiments, the 0.2% proof stress in a direction perpendicular to the rolling direction, a direction parallel to the rolling direction, a direction inclined at 45° to the rolling direction, and a direction inclined at 22.5° to the rolling direction can be made similar to that of the copper alloy sheet of the first embodiment. Furthermore, in the copper alloy sheets of the second and third embodiments, the electrical conductivity in a direction parallel to the rolling direction can be made similar to that of the copper alloy sheet of the first embodiment.

[0045] The copper alloy sheets of the second and third embodiments can be manufactured by the above-described method for manufacturing a copper alloy sheet of the present embodiment.

[0046] [Fourth embodiment] A copper alloy sheet of a fourth embodiment will be described. Note that descriptions of configurations that overlap between the copper alloy sheet of the fourth embodiment and the copper alloy sheets of the first, second, and third embodiments will be omitted as appropriate. The copper alloy sheet of the fourth embodiment is a copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, and the balance being Cu and unavoidable impurities.

[0047] In the copper alloy sheet of the fourth embodiment, when the tensile strengths in a direction perpendicular to the rolling direction, a direction parallel to the rolling direction, a direction inclined at 45° to the rolling direction, and a direction inclined at 22.5° to the rolling direction are designated as tensile strength A, tensile strength B, tensile strength C, and tensile strength D, respectively, the average values ​​of tensile strength A, tensile strength B, tensile strength C, and tensile strength D are 950 MPa or more. This makes it possible to suppress deformation of the copper alloy sheet during the manufacturing process of electronic components. The average value may be 986 MPa or more. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacturing process of electronic components.

[0048] In the copper alloy sheet of the fourth embodiment, the tensile strength in the direction perpendicular to the rolling direction, the direction parallel to the rolling direction, the direction inclined at 45° to the rolling direction, and the direction inclined at 22.5° to the rolling direction can be made similar to those of the copper alloy sheets of the first, second, and third embodiments. The copper alloy sheet of the fourth embodiment can be manufactured by the manufacturing method of the copper alloy sheet of the present embodiment described above.

[0049] [Fifth Embodiment] A copper alloy sheet of a fifth embodiment will be described. Note that descriptions of configurations that overlap between the copper alloy sheet of the fifth embodiment and the copper alloy sheets of the first, second, and third embodiments will be omitted as appropriate. The copper alloy sheet of the fifth embodiment is a copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, and the balance being Cu and unavoidable impurities.

[0050] In the copper alloy sheet of the fifth embodiment, when the tensile strengths in a direction perpendicular to the rolling direction, a direction parallel to the rolling direction, a direction inclined at 45° to the rolling direction, and a direction inclined at 22.5° to the rolling direction are defined as tensile strength A, tensile strength B, tensile strength C, and tensile strength D, respectively, the minimum value of tensile strength A, tensile strength B, tensile strength C, and tensile strength D is 930 MPa or more. This makes it possible to suppress deformation of the copper alloy sheet during the manufacturing process of electronic components. The minimum value may be 961 MPa or more. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacturing process of electronic components.

[0051] In the copper alloy sheet of the fourth embodiment, the tensile strength in the direction perpendicular to the rolling direction, the direction parallel to the rolling direction, the direction inclined at 45° to the rolling direction, and the direction inclined at 22.5° to the rolling direction can be made similar to those of the copper alloy sheets of the first, second, and third embodiments. The copper alloy sheet of the fourth embodiment can be manufactured by the manufacturing method of the copper alloy sheet of the present embodiment described above.

[0052] [Electronic Component] The electronic component of this embodiment is an electronic component including the copper alloy sheet of the first, second, and third embodiments described above (hereinafter also referred to as the copper alloy sheet of this embodiment). More specifically, the electronic component of this embodiment contains a copper alloy component manufactured from the copper alloy sheet of this embodiment. Examples of electronic components include semiconductor packages. The miniaturized copper alloy components that can be manufactured from the copper alloy sheet of this embodiment have properties that suppress deformation during the electronic component manufacturing process, making it suitable to use the copper alloy sheet of this embodiment 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 the copper alloy sheet 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 include the copper alloy sheet of the above-described embodiment.

[0053] Although the embodiments of the present disclosure have been described above, the copper alloy sheet, electronic component, and method for manufacturing a copper alloy sheet according to the present disclosure are not limited to the above examples and can be modified as appropriate.

[0054] (Aspects of the Present Disclosure) A first aspect of the present disclosure is a copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, and the balance consisting of Cu and unavoidable impurities, and having a tensile strength of 930 MPa or more in a direction perpendicular to the rolling direction.

[0055] A second aspect of the present disclosure is the copper alloy sheet according to the first aspect, further containing 0.010 to 5.0 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.

[0056] A third aspect of the present disclosure is the copper alloy sheet according to the first or second aspect, further containing 0.010 to 0.50 mass% of Cr.

[0057] A fourth aspect of the present disclosure is the copper alloy sheet according to any one of the first to third aspects, wherein the tensile strength in the perpendicular direction is 1000 MPa or more.

[0058] A fifth aspect of the present disclosure is the copper alloy sheet according to any one of the first to fourth aspects, wherein the 0.2% yield strength in a direction perpendicular to the rolling direction is 895 MPa or more.

[0059] A sixth aspect of the present disclosure is the copper alloy sheet according to any one of the first to fifth aspects, wherein the tensile strength in a direction parallel to the rolling direction is 870 MPa or more.

[0060] A seventh aspect of the present disclosure is the copper alloy sheet according to any one of the first to sixth aspects, wherein the 0.2% yield strength in a direction parallel to the rolling direction is 845 MPa or more.

[0061] An eighth aspect of the present disclosure is the copper alloy sheet according to any one of the first to seventh aspects, wherein the tensile strength in a direction inclined at 45° with respect to the rolling direction is 885 MPa or more.

[0062] A ninth aspect of the present disclosure is the copper alloy sheet according to any one of the first to eighth aspects, wherein the tensile strength in a direction inclined at 22.5° with respect to the rolling direction is 880 MPa or more.

[0063] A tenth aspect of the present disclosure is the copper alloy sheet according to any one of the first to ninth aspects, wherein the electrical conductivity in a direction parallel to the rolling direction is 35% IACS or more.

[0064] An eleventh aspect of the present disclosure is a copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, and the balance consisting of Cu and unavoidable impurities, and having a tensile strength of 885 MPa or more in a direction inclined at 45° to the rolling direction.

[0065] A twelfth aspect of the present disclosure is the copper alloy sheet according to the eleventh aspect, further containing 0.010 to 5.0 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.

[0066] A thirteenth aspect of the present disclosure is the copper alloy sheet according to the eleventh or twelfth aspect, further containing 0.010 to 0.50 mass% of Cr.

[0067] A fourteenth aspect of the present disclosure is the copper alloy sheet according to any one of the eleventh to thirteenth aspects, wherein the tensile strength in the direction inclined at 45° is 900 MPa or more.

[0068] A fifteenth aspect of the present disclosure is the copper alloy sheet according to any one of the eleventh to fourteenth aspects, wherein the 0.2% yield strength in a direction inclined at 45° with respect to the rolling direction is 845 MPa or more.

[0069] A sixteenth aspect of the present disclosure is the copper alloy sheet according to any one of the eleventh to fifteenth aspects, wherein the tensile strength in a direction parallel to the rolling direction is 870 MPa or more.

[0070] A seventeenth aspect of the present disclosure is the copper alloy sheet according to any one of the eleventh to sixteenth aspects, wherein the tensile strength in a direction perpendicular to the rolling direction is 930 MPa or more.

[0071] An eighteenth aspect of the present disclosure is the copper alloy sheet according to any one of the eleventh to seventeenth aspects, wherein the tensile strength in a direction inclined at 22.5° with respect to the rolling direction is 880 MPa or more.

[0072] A 19th aspect of the present disclosure is the copper alloy sheet according to any one of the 11th to 18th aspects, wherein the electrical conductivity in a direction parallel to the rolling direction is 35% IACS or more.

[0073] A twentieth aspect of the present disclosure is a copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the balance being Cu and unavoidable impurities, and having a tensile strength of 880 MPa or more in a direction inclined at 22.5° with respect to the rolling direction.

[0074] A twenty-first aspect of the present disclosure is the copper alloy sheet according to the twenty-first aspect, further containing 0.010 to 5.0 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.

[0075] A 22nd aspect of the present disclosure is the copper alloy sheet according to the 20th or 21st aspect, further containing 0.010 to 0.50 mass% of Cr.

[0076] A 23rd aspect of the present disclosure is the copper alloy sheet according to any one of the 20th to 22nd aspects, wherein the tensile strength in the direction inclined at 22.5° is 900 MPa or more.

[0077] A 24th aspect of the present disclosure is the copper alloy sheet according to any one of the 20th to 23rd aspects, wherein the 0.2% yield strength in a direction inclined at 22.5° with respect to the rolling direction is 845 MPa or more.

[0078] A 25th aspect of the present disclosure is the copper alloy sheet according to any one of the 20th to 24th aspects, wherein the tensile strength in a direction parallel to the rolling direction is 870 MPa or more.

[0079] A 26th aspect of the present disclosure is the copper alloy sheet according to any one of the 20th to 25th aspects, wherein the tensile strength in a direction perpendicular to the rolling direction is 930 MPa or more.

[0080] A 27th aspect of the present disclosure is the copper alloy sheet according to any one of the 20th to 26th aspects, wherein the tensile strength in a direction inclined at 45° with respect to the rolling direction is 885 MPa or more.

[0081] A 28th aspect of the present disclosure is the copper alloy sheet according to any one of the 20th to 27th aspects, in which the electrical conductivity in a direction parallel to the rolling direction is 35% IACS or more.

[0082] A 29th aspect of the present disclosure is an electronic component including the copper alloy sheet according to any one of the first to 28th aspects.

[0083] A 30th aspect of the present disclosure is a method for producing a copper alloy sheet, comprising the steps of: hot-rolling an ingot of a copper alloy containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the balance being Cu and inevitable impurities; solution-treating the obtained copper alloy intermediate; aging-treating the copper alloy intermediate; and finish-cold-rolling the copper alloy intermediate, in this order; wherein when the formula (X = (A × B) / (C)) is expressed using the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), and tensile strength (C (MPa)) of the copper alloy intermediate after the solution-treating step, the value of X in the formula is 17.5 or less.

[0084] A thirty-first aspect of the present disclosure is the method for producing a copper alloy sheet according to the thirtieth aspect, wherein the copper alloy sheet further contains 0.010 to 0.50 mass% of Cr.

[0085] 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. Copper alloy sheets of Example 1 and Comparative Example 1 were produced under the conditions shown in Table 1. Using electrolytic copper as a raw material, copper alloys having the compositions shown in Table 1 were melted and cast using an atmospheric melting furnace. The ingots were subjected to homogenization annealing at 980°C for 3 hours, followed by hot rolling to a thickness of 10 mm and facing. Subsequently, intermediate cold rolling was performed, and solution treatment and aging treatment were performed under the conditions shown in Table 1. Next, the obtained intermediate was pickled and polished, and then finish cold rolling to a thickness of 0.151 mm with the working degree shown in Table 1. Furthermore, stress relief annealing was performed in the air under the conditions shown in Table 1. The copper alloy sheets after stress relief annealing were cooled by air cooling to obtain the copper alloy sheets of Example 1 and Comparative Example 1.

[0086]

[0087] The physical properties of the obtained copper alloy sheets and intermediates thereof of Example 1 and Comparative Example 1 were measured by the following methods. The results are shown in Table 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.

[0088] [Tensile strength (TS)] Measured using a tensile tester in accordance with JIS-Z2241 (2011). Tensile strength was measured in the direction parallel to the rolling direction, the direction perpendicular to the rolling direction, the direction inclined at 45° to the rolling direction, and the direction inclined at 22.5° to the rolling direction. Specifically, JIS 13B test pieces were prepared from each sample using a press so that the tensile direction was a predetermined direction relative 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 Table 2.

[0089] [0.2% Proof Stress] Measured using a tensile tester in accordance with JIS-Z2241 (2011) (offset method, 0.2%). 0.2% proof stress was measured in the direction parallel to the rolling direction, the direction perpendicular to the rolling direction, the direction inclined at 45° to the rolling direction, and the direction inclined at 22.5° to the rolling direction. Specifically, test pieces were prepared in the same manner as for the tensile strength described above. Tests were also conducted under the same conditions as for the tensile strength described above.

[0090] [Breaking elongation] Measurement was performed using a tensile testing machine in accordance with JIS-Z2241 (2011). Breaking elongation (%) was measured in the direction parallel to the rolling direction, the direction perpendicular to the rolling direction, the direction inclined at 45° to the rolling direction, and the direction inclined at 22.5° to the rolling direction. Specifically, test pieces were prepared in the same manner as for the tensile strength described above. Tests were also performed under the same conditions as for the tensile strength described above. The breaking elongation was measured using the following formula. The definitions of final gauge length and original gauge length were the same as in JIS-Z2241 (2011). Breaking elongation (%) = (final gauge length - original gauge length) / original gauge length

[0091] [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, a direction perpendicular to the rolling direction, a direction inclined at 45° to the rolling direction, and a direction inclined at 22.5° to the rolling direction. The measurement was performed with a gauge length (distance between electrical resistance measurements) of 50 mm.

[0092]

[0093] As shown in Table 2, it was found that by manufacturing under the conditions of each process, particularly by relatively increasing the treatment temperatures of the solution treatment and the aging treatment and relatively increasing the degree of finish cold rolling, the tensile strength in various directions relative to the rolling direction can be improved while providing high electrical conductivity. Therefore, the refined copper alloy parts for electronic parts manufactured from the copper alloy sheet of Example 1 can suppress deformation during the manufacturing process of the electronic parts.

[0094] According to the present disclosure, it is possible to provide a copper alloy sheet having high electrical conductivity and high strength, an electronic component including the same, and a method for manufacturing the copper alloy sheet.

Claims

1. A copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the remainder being Cu and unavoidable impurities, and having a tensile strength of 930 MPa or more in a direction perpendicular to the rolling direction.

2. The copper alloy sheet according to claim 1, further containing 0.010 to 5.0 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.

3. The copper alloy sheet according to claim 1, further containing 0.010 to 0.50 mass% of Cr.

4. The copper alloy sheet according to claim 1, wherein the tensile strength in the perpendicular direction is 1000 MPa or more.

5. The copper alloy sheet according to claim 1, having a 0.2% yield strength in a direction perpendicular to the rolling direction of 895 MPa or more.

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

7. The copper alloy sheet according to claim 1, having a 0.2% yield strength in a direction parallel to the rolling direction of 845 MPa or more.

8. The copper alloy sheet according to claim 1, having a tensile strength of 885 MPa or more in a direction inclined at 45° to the rolling direction.

9. The copper alloy sheet according to claim 1, having a tensile strength of 880 MPa or more in a direction inclined at 22.5° to the rolling direction.

10. The copper alloy sheet according to claim 1, having an electrical conductivity of 35% IACS or more in a direction parallel to the rolling direction.

11. A copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the remainder being Cu and unavoidable impurities, and having a tensile strength of 885 MPa or more in a direction inclined at 45° to the rolling direction.

12. The copper alloy sheet according to claim 11, further containing 0.010 to 5.0 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.

13. The copper alloy sheet according to claim 11, further containing 0.010 to 0.50 mass% of Cr.

14. The copper alloy sheet according to claim 11, wherein the tensile strength in the direction inclined at 45° is 900 MPa or more.

15. The copper alloy sheet according to claim 11, wherein the 0.2% yield strength in a direction inclined at 45° to the rolling direction is 845 MPa or more.

16. The copper alloy sheet according to claim 11, having a tensile strength of 870 MPa or more in a direction parallel to the rolling direction.

17. The copper alloy sheet according to claim 11, having a tensile strength in a direction perpendicular to the rolling direction of 930 MPa or more.

18. The copper alloy sheet according to claim 11, having a tensile strength of 880 MPa or more in a direction inclined at 22.5° to the rolling direction.

19. The copper alloy sheet according to claim 11, having an electrical conductivity of 35% IACS or more in a direction parallel to the rolling direction.

20. A copper alloy sheet containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the remainder being Cu and unavoidable impurities, and having a tensile strength of 880 MPa or more in a direction inclined at 22.5° to the rolling direction.

21. The copper alloy sheet according to claim 20, further containing 0.010 to 5.0 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.

22. The copper alloy sheet according to claim 20, further containing 0.010 to 0.50 mass% of Cr.

23. The copper alloy sheet according to claim 20, wherein the tensile strength in the direction inclined at 22.5° is 900 MPa or more.

24. The copper alloy sheet according to claim 20, wherein the 0.2% yield strength in a direction inclined at 22.5° to the rolling direction is 845 MPa or more.

25. The copper alloy sheet according to claim 20, having a tensile strength of 870 MPa or more in a direction parallel to the rolling direction.

26. The copper alloy sheet according to claim 20, having a tensile strength of 930 MPa or more in a direction perpendicular to the rolling direction.

27. The copper alloy sheet according to claim 20, having a tensile strength of 885 MPa or more in a direction inclined at 45° to the rolling direction.

28. The copper alloy sheet according to claim 20, having an electrical conductivity of 35% IACS or more in a direction parallel to the rolling direction.

29. An electronic component comprising the copper alloy sheet according to any one of claims 1 to 28.

30. A method for producing a copper alloy sheet, comprising the steps of: hot rolling an ingot of a copper alloy containing 1.5 to 4.6 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.3 mass% Si, with the balance being Cu and unavoidable impurities; solution treating the obtained copper alloy intermediate; aging the copper alloy intermediate; and finish cold rolling the copper alloy intermediate, in this order; wherein when the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), and tensile strength (C (MPa)) of the copper alloy intermediate after the solution treating step are used to express the formula (X = (A x B) / (C)), the value of X in the formula is 17.5 or less.

31. The method for producing a copper alloy sheet according to claim 30, wherein the copper alloy sheet further contains 0.010 to 0.50 mass % of Cr.

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