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

Abstract

The objective of the present disclosure is to provide a copper alloy sheet having high strength. A copper alloy sheet according to the present disclosure contains 1.5-4.5 mass% of Ni and 0.10-1.2 mass% of Si, with the remainder comprising Cu and unavoidable impurities, and has a tensile strength of 930 MPa or more in a direction perpendicular to the rolling direction.

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] In recent years, with the increasing sophistication of electronic components, copper alloy parts (or specific portions of copper alloy parts) manufactured from Corson alloy copper alloy sheets to be included in electronic components have become highly miniaturized. This demand for copper alloy sheets that maintain high electrical conductivity while also improving their properties to accommodate this miniaturization is creating a need for further miniaturization. For example, in semiconductor packages, which are electronic components, lead frames manufactured from copper alloy sheets for constructing semiconductor packages, particularly the leads within the lead frames, have become narrower as the functionality of semiconductor packages has increased. Leads are internal wiring (pins) within semiconductor packages that connect to external wiring. To increase the number of pins and achieve higher functionality, the leads have become narrower. However, such miniaturization can sometimes result in insufficient lead strength, which can lead to deformation and difficulty in maintaining their shape with high precision during lead frame and semiconductor package manufacturing processes (e.g., processes for producing desired lead frames by half-etching copper alloy sheets, and processes for arranging semiconductor elements on lead frames and then wire-bonding the leads to the semiconductor elements). As a result, semiconductor packages may not be manufactured efficiently, and there is a demand for copper alloy sheets with further improved strength.

[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 above-mentioned problems of the conventional 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 have 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 and Si, or Ni, Si and Mg, and having high tensile strength in a predetermined direction relative to the rolling direction, can solve the above-mentioned 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 4.5 mass% Ni, 0.10 to 1.2 mass% Si, and the balance being Cu and unavoidable impurities, and has a tensile strength of 930 MPa or more in a direction perpendicular to the rolling direction.

[0008] In another embodiment, the copper alloy sheet of the present disclosure contains 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, with the balance being Cu and unavoidable impurities, and has a tensile strength of 885 MPa or more in a direction inclined at 45° to the rolling direction.

[0009] In still another embodiment, the copper alloy sheet of the present disclosure contains 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, with the balance being Cu and unavoidable impurities, and has a tensile strength of 880 MPa or more in a direction inclined at 22.5° to the rolling direction.

[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 4.5 mass% Ni, 0.10 to 1.2 mass% Si, with the balance being Cu and unavoidable impurities; solution-treating the obtained copper alloy intermediate; cold-rolling the copper alloy intermediate; aging-treating the copper alloy intermediate; and finish-cold-rolling the copper alloy intermediate, in this order; and calculating an equation (X=(A (% IACS)) using the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), tensile strength (C (MPa)), and plate thickness (D (mm)) of the copper alloy intermediate after the solution-treating step. 2 × B) / (C × D)), the value of X in the formula is 500 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 shows the electrical conductivity (A), 0.2% yield strength (B), tensile strength (C), and thickness (D) of a copper alloy intermediate after solution treatment, calculated by the formula (X = (A 2 1 is a graph summarizing the relationship between a parameter X represented by ((x × B) / (c × D) ... (1)) and the tensile strength (MPa) in a direction parallel to the rolling direction of a copper alloy plate (for example, after aging treatment).

[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 "a or more and b or less," where 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 4.5 mass% Ni, 0.10 to 1.2 mass% Si, and the remainder being Cu and unavoidable impurities. That is, the copper alloy sheet of this embodiment is a Cu-Ni-Si alloy. When Ni and Si are subjected to an aging treatment, Ni and Si form precipitated particles of an intermetallic compound mainly composed of Ni2Si, which significantly increases the strength of the copper alloy sheet. In addition, the precipitation of Ni2Si during the aging treatment provides high electrical conductivity.

[0016] In the composition of the copper alloy sheet of the first embodiment, the Ni concentration is 1.5 to 4.5 mass%, and the Si concentration is 0.10 to 1.2 mass%. This allows the copper alloy sheet to maintain its high electrical conductivity while further improving its strength. If the Ni concentration is less than 1.5 mass% or the Si concentration is less than 0.10 mass%, the desired strength cannot be obtained even when the other component is added. If the Ni concentration exceeds 4.5 mass% or the Si concentration exceeds 1.2 mass%, sufficient strength is obtained, but electrical conductivity decreases. The Ni concentration is preferably 1.6 to 4.2 mass%. The lower limit of the Ni concentration can be 1.6 mass%, preferably 2.2 mass%. The upper limit of the Ni concentration can be 4.2 mass%, preferably 3.0 mass%. The Ni concentration can also be 2.2 to 4.2 mass%, or 1.6 to 3.0 mass%. The Si concentration is preferably 0.25 to 1.2 mass %, more preferably 0.25 to 0.9 mass %, and even more preferably 0.4 to 0.7 mass %.

[0017] As mentioned above, Ni-Si-based precipitates formed by Ni and Si are considered to be intermetallic compounds mainly composed of Ni2Si. However, not all Ni and Si in copper alloys are converted into precipitates by aging treatment during the manufacturing process of copper alloy sheets, and some may exist in a solid solution state in the Cu matrix. Although solid-solution Ni and Si can slightly improve the strength of copper alloy sheets, this 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 and Si be close to the composition ratio of the precipitate Ni2Si. Therefore, the mass ratio of Ni to Si is preferably 3.4 to 5.4, more preferably 3.8 to 5.0.

[0018] In the composition of the copper alloy sheet of the first embodiment, one or more elements selected from the group consisting of Mg, Fe, P, Mn, Co, Pb, Zn, and Cr (hereinafter also referred to as "additive elements") may be further contained in a total amount of 0.050 to 1.00 mass% as an element other than the above elements. This can improve the strength, heat resistance, stress relaxation resistance, etc. of the copper alloy sheet. When the total amount of additive elements is 0.050 mass% or more, the desired effects described above tend to be easily obtained. Furthermore, when the total amount of additive elements is 1.00 mass% or less, it is possible to prevent a decrease in electrical conductivity while obtaining the desired properties. The total amount of additive elements is preferably 0.075 to 0.60 mass%, more preferably 0.10 to 0.40 mass%.

[0019] The composition of the copper alloy sheet of the first embodiment may contain 0.050 to 0.80 mass% Mg. This can improve stress relaxation resistance and the like. More specifically, when the Mg content is 0.050 mass% or more, the above-described desired effects tend to be easily obtained. Furthermore, when the Mg content is 0.80 mass% or less, it is possible to prevent a decrease in electrical conductivity while obtaining the desired properties. The Mg concentration is preferably 0.050 to 0.60 mass%, more preferably 0.050 to 0.30 mass%, and even more preferably 0.10 to 0.40 mass%. Furthermore, when the copper alloy sheet of the first embodiment contains Mg, one or more elements selected from the group consisting of Fe, P, Mn, Co, Pb, Zn, and Cr other than Mg listed above may also be contained in addition to Mg. In this case, in addition to Mg, one or more elements selected from the group consisting of Fe, P, Mn, Co, Pb, Zn and Cr may be contained in a total amount of 0.050 to 1.00 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. An element other than Y may be selected as the internal standard. 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 30-40 mm diameter and 50-80 mm thick, then cut to a thickness of approximately 10-20 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 certain 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 a high tensile strength in a direction perpendicular to the rolling direction. Having a tensile strength of 930 MPa or more in the perpendicular direction makes it possible to suppress deformation of a miniaturized 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. Specifically, a deformable copper alloy part or a portion thereof may 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 a 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 part (e.g., a lead frame), can be suppressed. The tensile strength in the direction perpendicular to the rolling direction is preferably 950 MPa or more, more preferably 965 MPa or more. There is no particular upper limit to the tensile strength in the direction perpendicular 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. 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. The tensile tester used for the tensile test can be an Autocom AC-100KN-C manufactured by TSE Co., Ltd. or an equivalent device. 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 880 MPa or more, and more preferably 888 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, more preferably 908 MPa or more. There is no particular limitation on the upper limit of 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 890 MPa or more, more preferably 899 MPa or more. There is no particular limitation on the upper limit of 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 905 MPa or more, more preferably 916 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. In addition, 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 be small, etc.

[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 840 MPa or more. This makes it possible to more effectively suppress deformation of a finely divided 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 850 MPa or more, more preferably 858 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 855 MPa or more, and more preferably 866 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 840 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 850 MPa or more, more 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 a conductivity of 35.0% IACS or more in a direction parallel to the rolling direction. A conductivity of 35.0% IACS or more allows the copper alloy sheet to be effectively used as a copper alloy part for electronic components. The conductivity in a direction parallel to the rolling direction is preferably 40.0% IACS or more, more preferably 43.7% IACS. The conductivity in a direction parallel to the rolling direction can be measured by the method described in the Examples section below. Furthermore, the 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.

[0031] Hereinafter, a method for producing a copper alloy sheet of this embodiment will be described. The method for producing a copper alloy sheet of this embodiment includes, in this order, a step of hot-rolling an ingot of a copper alloy containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, and the balance consisting of Cu and unavoidable impurities, a step of solution-treating the obtained copper alloy intermediate, a step of cold-rolling the copper alloy intermediate, a step of aging the copper alloy intermediate, and a step of finish-cold-rolling the copper alloy intermediate. Furthermore, the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), tensile strength (C (MPa)), and sheet thickness (D (mm)) of the copper alloy intermediate after the solution-treatment step can be calculated by the formula (X = (A 2 When the formula (C × B) / (C × D) is expressed, the value of X in the formula is 500 or less. In the manufacturing method of the copper alloy sheet of this embodiment, cold rolling may be performed after the step of hot rolling the ingot and before the step of solution treatment (this cold rolling is also referred to as first intermediate cold rolling, and the cold rolling after the solution treatment is also referred to as second intermediate cold rolling). After performing each of the above steps, grinding, polishing, shot blasting, pickling, etc. can be appropriately performed to remove oxide scale from the surface.

[0032] More specifically, in the manufacturing method of the copper alloy sheet of this embodiment, it is essential to perform a second intermediate cold rolling after the solution treatment and before the aging treatment. The solution treatment is a heat treatment that dissolves silicides such as Ni-Si compounds in the Cu matrix and simultaneously recrystallizes the Cu matrix. The solution treatment can also be performed by hot rolling. The aging treatment precipitates the silicides dissolved in the solution treatment as fine particles of an intermetallic compound mainly composed of NiSi. This aging treatment increases strength and electrical conductivity. Furthermore, by performing a second intermediate cold rolling between the solution treatment and the aging treatment, the amount and size of the fine particles that precipitate during the aging treatment and contribute to the increase in strength can be adjusted. Therefore, performing the second intermediate cold rolling can further increase the strength of the copper alloy sheet, compared to when the second intermediate cold rolling is not performed.

[0033] The method for producing the copper alloy sheet of this embodiment is not particularly limited, but more specifically, can be the following method. The method for producing the copper alloy sheet of this embodiment can first include a step of melting and casting a copper alloy raw material having the desired composition described above. In this step, the copper alloy raw material is melted using a method similar to a general copper alloy melting method, and then an ingot is produced by continuous casting, semi-continuous casting, or the like. For example, first, raw materials such as electrolytic copper, Ni, 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 desired dimensions and cast into an ingot.

[0034] The method for producing a copper alloy sheet according to this embodiment may include a step of hot rolling an ingot. The hot rolling of the ingot is not particularly limited, but may be carried out, for example, in several passes at 950°C to 500°C. The total reduction ratio of the hot rolling is preferably 90% or more. The reduction ratio (%) is expressed as follows: (TB - TA) / TB) x 100, where TB is the thickness of the workpiece to be rolled and TA is the thickness of the workpiece after rolling.

[0035] The method for producing a copper alloy sheet according to the present embodiment may include a step of performing a first intermediate cold rolling of the intermediate. The cold rolling is not particularly limited, but may be performed, for example, in several passes. It is preferable to perform one or more passes of rolling. The total reduction ratio is preferably 80% or more, more preferably 90% or more.

[0036] The method for producing a copper alloy sheet according to the present embodiment may include a step of subjecting an intermediate to solution treatment after the above-described optional first intermediate cold rolling. Figure 1 shows the electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), tensile strength (C (MPa)), and sheet thickness (D (mm)) of the copper alloy intermediate after the solution treatment, calculated using the formula (X = (A 21 is a graph summarizing the relationship between a parameter X represented by ((x × B) / (c × D) (1)) and the tensile strength (MPa) in a direction parallel to the rolling direction of a copper alloy sheet after aging treatment (note that the 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). By setting the value of the parameter X to 500 or less, it becomes easier to produce the copper alloy sheet of the present disclosure.

[0037] The heat treatment temperature for the solution treatment can be, for example, 600 to 850°C. The heat treatment time can be 10 seconds to 5 minutes. The value of parameter X can be reduced by relatively increasing the heat treatment temperature and relatively increasing the heat treatment time for the solution treatment. By setting the value of parameter X to 500 or less and appropriately selecting and combining the heat treatment temperature and heat treatment time for the solution treatment, Ni—Si compounds can be solid-dissolved in the Cu matrix, and the Cu matrix can be recrystallized at the same time. This allows precipitates that contribute to strength during aging treatment to be precipitated, thereby 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, setting the value of parameter X to 500 or less allows similarly high strength to 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 650 to 800° C., and the heat treatment time is preferably 20 seconds to 3 minutes.

[0038] The method for producing a copper alloy sheet according to this embodiment may include a step of performing second intermediate cold rolling on the intermediate body after the solution treatment. The cold rolling of the intermediate body is not particularly limited, but may be performed, for example, in several passes. It is preferable to perform one or more passes of rolling. The total reduction ratio of the second intermediate cold rolling is preferably 5% or more, more preferably 10% or more. The total reduction ratio is preferably 90% or less, more preferably 60% or less. By setting the reduction ratio within the desired range, it is possible to improve strength while maintaining high electrical conductivity in various directions relative to the rolling direction. In order to sufficiently increase the strength and electrical conductivity of the copper alloy sheet, the tensile strength of the intermediate body after the second intermediate cold rolling in a direction parallel to the rolling direction may be 500 MPa or more. The total reduction ratio of the first intermediate cold rolling and the second intermediate cold rolling is preferably 90% or more, more preferably 93% or more.

[0039] The method for producing a copper alloy sheet according to this embodiment may include a step of aging the intermediate body after the second intermediate cold rolling. 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 limits of the above ranges, the amount of NiSi precipitated tends to be sufficient, making it easier to obtain sufficient strength. By setting the aging temperature and time at or below the upper limits of the above ranges, coarsening of precipitates and re-dissolution can be prevented, making it easier to sufficiently improve strength and electrical conductivity. 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 750 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.

[0040] 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 can impart processing strain to the material, improving its strength. A processing ratio of 40% or more in the finish cold rolling tends to facilitate sufficient improvement of strength. The processing ratio of the finish cold rolling is preferably 40 to 80%. A processing ratio of 80% or less can prevent a decrease in electrical conductivity due to processing strain from heavy processing. To sufficiently increase the strength and electrical conductivity of the copper alloy sheet, the tensile strength of the intermediate body after the finish cold rolling in a direction parallel to the rolling direction may be 850 MPa or more. Furthermore, the electrical conductivity of the intermediate body after the finish cold rolling in a direction parallel to the rolling direction may be 40% IACS or more.

[0041] 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.

[0042] 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.

[0043] [Second embodiment] Next, a copper alloy sheet of a second embodiment will be described. Note that the description of the configurations that overlap between the copper alloy sheet of the second embodiment and the copper alloy sheet of the first embodiment will be omitted as appropriate. The copper alloy sheet of the second embodiment is a copper alloy sheet containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, and the balance being Cu and unavoidable impurities.

[0044] In the composition of the copper alloy sheet of the second embodiment, the Ni concentration is 1.5 to 4.5 mass%, the Si concentration is 0.10 to 1.2 mass%, and the Mg concentration is 0.050 to 0.80 mass%, thereby improving the stress relaxation resistance and further improving the strength of the copper alloy sheet while maintaining the high electrical conductivity of the copper alloy sheet.

[0045] The Ni concentration is preferably 1.6 to 4.2 mass%. The lower limit of the Ni concentration can be 1.6 mass%, preferably 2.2 mass%. The upper limit of the Ni concentration can be 4.2 mass%, preferably 3.0 mass%. The Ni concentration can be 2.2 to 4.2 mass%, or 1.6 to 3.0 mass%. The Si concentration is preferably 0.25 to 1.2 mass%, more preferably 0.25 to 0.9 mass%, and even more preferably 0.4 to 0.7 mass%.

[0046] The composition of the copper alloy sheet of the second embodiment may contain one or more elements selected from the group consisting of Fe, P, Mn, Co, Pb, Zn, and Cr. In this case, in addition to Mg, one or more elements selected from the group consisting of Fe, P, Mn, Co, Pb, Zn, and Cr may be contained in an amount of 0.050 to 1.00 mass%, preferably 0.075 to 0.60 mass%, more preferably 0.10 to 0.40 mass% in total.

[0047] 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, more preferably 908 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.

[0048] In the copper alloy sheet of the second embodiment, the tensile strength in a direction perpendicular to the rolling direction, a direction parallel 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. Moreover, in the copper alloy sheet of the second embodiment, 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.

[0049] The copper alloy sheet of the second embodiment can be manufactured by the above-described method for manufacturing a copper alloy sheet of the present embodiment.

[0050] [Third Embodiment] Next, a copper alloy sheet of a third embodiment will be described. Note that descriptions of configurations that overlap between the copper alloy sheet of the third embodiment and the copper alloy sheets of the first and second embodiments will be omitted as appropriate. The copper alloy sheet of the third embodiment is a copper alloy sheet containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, and the balance being Cu and unavoidable impurities.

[0051] 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 890 MPa or more, more preferably 899 MPa or more. There is no particular limitation on the upper limit of 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.

[0052] In the copper alloy sheet of the third embodiment, the tensile strength in a direction perpendicular to the rolling direction, a direction parallel to the rolling direction, and a direction inclined at 22.5° to the rolling direction can be made similar to those of the copper alloy sheets of the first and second embodiments. In addition, in the copper alloy sheet of the third embodiment, 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 those of the copper alloy sheets of the first and second embodiments.

[0053] The copper alloy sheet of the third embodiment can be manufactured by the above-described method for manufacturing a copper alloy sheet of the present embodiment.

[0054] [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 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, and the balance being Cu and unavoidable impurities.

[0055] In the copper alloy sheet of the fourth embodiment, when the tensile strength in the direction perpendicular to the rolling direction is defined as tensile strength TA (MPa), the tensile strength in the direction parallel to the rolling direction is defined as tensile strength TB (MPa), the tensile strength in the direction inclined at 45° to the rolling direction is defined as tensile strength TC (MPa), and the tensile strength in the direction inclined at 22.5° to the rolling direction is defined as tensile strength TD (MPa), the average values ​​of the tensile strengths TA, TB, TC, and TD are 882 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 915 MPa or more. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacturing process of electronic components.

[0056] 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 embodiment, the second embodiment, and the third embodiment.

[0057] The copper alloy sheet of the fourth embodiment can be manufactured by the above-described method for manufacturing a copper alloy sheet of the present embodiment.

[0058] [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 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, and the balance being Cu and unavoidable impurities.

[0059] In the copper alloy sheet of the fifth embodiment, when the tensile strength in the direction perpendicular to the rolling direction is defined as tensile strength TA (MPa), the tensile strength in the direction parallel to the rolling direction is defined as tensile strength TB (MPa), the tensile strength in the direction inclined at 45° to the rolling direction is defined as tensile strength TC (MPa), and the tensile strength in the direction inclined at 22.5° to the rolling direction is defined as tensile strength TD (MPa), the minimum value of the tensile strengths TA, TB, TC, and TD is 862 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 888 MPa or more. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacturing process of electronic components.

[0060] In the copper alloy sheet of the fifth 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 embodiment, the second embodiment, and the third embodiment.

[0061] The copper alloy sheet of the fifth embodiment can be manufactured by the above-described method for manufacturing a copper alloy sheet of the present embodiment.

[0062] [Electronic Component] The electronic component of this embodiment is an electronic component including the copper alloy sheet of the above-described embodiment (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 manufacturing process of electronic components, so the copper alloy sheet of this embodiment is suitable for manufacturing semiconductor packages with many miniaturized structures. Note that 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, then supporting and fixing a semiconductor element on the lead frame, wire-bonding the semiconductor element to the leads to form internal wiring, and finally encapsulating the semiconductor element with a predetermined resin member. As described above, the electronic component of this embodiment may include the copper alloy sheet of the above-described embodiment.

[0063] 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.

[0064] (Aspects of the Present Disclosure) A first aspect of the present disclosure is a copper alloy sheet containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 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.

[0065] A second aspect of the present disclosure is the copper alloy sheet according to the first aspect, further containing 0.050 to 1.00 mass% in total of one or more elements selected from the group consisting of Mg, Fe, P, Mn, Co, Pb, Zn, and Cr.

[0066] A third aspect of the present disclosure is the copper alloy sheet according to the first or second aspect, further containing 0.050 to 0.80 mass% of Mg.

[0067] 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 950 MPa or more.

[0068] 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.

[0069] 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.

[0070] 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 840 MPa or more.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] An eleventh aspect of the present disclosure is a copper alloy sheet containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, with the balance 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.

[0075] A twelfth aspect of the present disclosure is the copper alloy sheet according to the eleventh aspect, wherein the tensile strength in the direction inclined at 45° is 900 MPa or more.

[0076] A thirteenth aspect of the present disclosure is the copper alloy sheet according to the eleventh or twelfth aspect, wherein a 0.2% yield strength in a direction inclined at 45° with respect to the rolling direction is 845 MPa or more.

[0077] 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 a direction parallel to the rolling direction is 870 MPa or more.

[0078] A fifteenth aspect of the present disclosure is the copper alloy sheet according to any one of the eleventh to fourteenth aspects, wherein the tensile strength in a direction perpendicular to the rolling direction is 930 MPa or more.

[0079] 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 inclined at 22.5° with respect to the rolling direction is 880 MPa or more.

[0080] A seventeenth aspect of the present disclosure is the copper alloy sheet according to any one of the eleventh to sixteenth aspects, wherein the electrical conductivity in a direction parallel to the rolling direction is 35% IACS or more.

[0081] An eighteenth aspect of the present disclosure is a copper alloy sheet containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, 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.

[0082] A nineteenth aspect of the present disclosure is the copper alloy sheet according to the eighteenth aspect, wherein the tensile strength in the direction inclined at 22.5° is 890 MPa or more.

[0083] A twentieth aspect of the present disclosure is the copper alloy sheet according to the eighteenth or nineteenth aspect, wherein a 0.2% yield strength in a direction inclined at 22.5° with respect to the rolling direction is 840 MPa or more.

[0084] A 21st aspect of the present disclosure is the copper alloy sheet according to any one of the 18th to 20th aspects, wherein the tensile strength in a direction parallel to the rolling direction is 870 MPa or more.

[0085] A twenty-second aspect of the present disclosure is the copper alloy sheet according to any one of the eighteenth to twenty-first aspects, wherein the tensile strength in a direction perpendicular to the rolling direction is 930 MPa or more.

[0086] A twenty-third aspect of the present disclosure is the copper alloy sheet according to any one of the eighteenth to twenty-second aspects, wherein the tensile strength in a direction inclined at 45° to the rolling direction is 885 MPa or more.

[0087] A 24th aspect of the present disclosure is the copper alloy sheet according to any one of the 18th to 23rd aspects, wherein the electrical conductivity in a direction parallel to the rolling direction is 35% IACS or more.

[0088] A twenty-fifth aspect of the present disclosure is an electronic component including the copper alloy sheet according to any one of the first to twenty-fourth aspects.

[0089] A twenty-sixth aspect of the present disclosure is a copper alloy ingot manufacturing method, comprising the steps of: hot-rolling an ingot of a copper alloy containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, with the balance being Cu and unavoidable impurities; solution-treating the obtained copper alloy intermediate; cold-rolling the copper alloy intermediate; aging-treating the copper alloy intermediate; and finish-cold-rolling the copper alloy intermediate, in this order; 2 × B) / (C × D)), the value of X in the formula is 500 or less.

[0090] A 27th aspect of the present disclosure is the method for producing a copper alloy sheet according to the 26th aspect, wherein the copper alloy sheet further contains 0.050 to 1.00 mass% in total of one or more elements selected from the group consisting of Mg, Fe, P, Mn, Co, Pb, Zn, and Cr.

[0091] 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 850 to 980°C for 25 minutes and then hot rolled to a thickness of 11.5 mm. After hot rolling, facing was performed. Then, first intermediate cold rolling, solution treatment, second intermediate cold rolling, and aging treatment were performed under the conditions shown in Table 1. Next, the obtained intermediate was pickled and polished, and finish cold rolling was performed to a thickness of 0.151 mm with the working ratio shown in Table 1. Furthermore, stress relief annealing was performed in the atmosphere 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.

[0092]

[0093] The obtained copper alloy sheets of Example 1 and Comparative Example 1 were subjected to the following measurements. 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.

[0094] [Tensile Strength (TS)] The tensile strength (TS) of the obtained copper alloy sheets was measured using a tensile testing machine in accordance with JIS-Z2241 (2011). The tensile strength was measured 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. 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.

[0095] [0.2% Proof Stress] The 0.2% proof stress (MPa) of the copper alloy was measured using a tensile tester in accordance with JIS-Z2241 (2011) (offset method, 0.2%). The 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 specimens were prepared using the same method as for the tensile strength described above. Tests were also conducted under the same conditions as for the tensile strength described above. Tests were conducted using two test specimens, and the average values ​​of the two data points are shown in Table 2.

[0096] [Elongation at break] The elongation at break (%) of the copper alloy was measured using a tensile tester in accordance with JIS-Z2241 (2011). The elongation at break (%) 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. The test was conducted using two test pieces, and the average value of the two data is shown in Table 2.

[0097] [Conductivity] The conductivity (EC: % IACS) was measured by the four-terminal method in accordance with JIS-H0505 (1975). A double bridge was used for the measurement, and the resistance was measured based on the average cross-sectional area method. The conductivity was measured at room temperature (25°C). The gauge length (distance between electrical resistance measurements) was 50 mm. The conductivity was measured 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 test was performed using two test pieces, and the average value of the two data is shown in Table 2.

[0098]

[0099] As shown in Table 2, it was found that by performing the second intermediate cold rolling between the solution treatment and the aging treatment, the tensile strength in various directions relative to the rolling direction was improved while maintaining 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.

[0100] According to the present disclosure, it is possible to provide a copper alloy sheet having 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 4.5 mass% Ni, 0.10 to 1.2 mass% Si, with the remainder being Cu and unavoidable impurities, and having a tensile strength of 930 MPa or more in the direction perpendicular to the rolling direction.

2. The copper alloy sheet according to claim 1, further containing 0.050 to 1.00 mass% in total of one or more elements selected from the group consisting of Mg, Fe, P, Mn, Co, Pb, Zn and Cr.

3. The copper alloy sheet according to claim 1, further containing 0.050 to 0.80 mass % of Mg.

4. The copper alloy sheet according to claim 1, wherein the tensile strength in the perpendicular direction is 950 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 840 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 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, 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, wherein the tensile strength in the direction inclined at 45° is 900 MPa or more.

13. 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.

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

15. 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.

16. 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.

17. 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.

18. A copper alloy sheet containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, 0.050 to 0.80 mass% Mg, 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.

19. The copper alloy sheet according to claim 18, wherein the tensile strength in the direction inclined at 22.5° is 890 MPa or more.

20. The copper alloy sheet according to claim 18, wherein the 0.2% yield strength in a direction inclined at 22.5° to the rolling direction is 840 MPa or more.

21. The copper alloy sheet according to claim 18, having a tensile strength in a direction parallel to the rolling direction of 870 MPa or more.

22. The copper alloy sheet according to claim 18, having a tensile strength in a direction perpendicular to the rolling direction of 930 MPa or more.

23. The copper alloy sheet according to claim 18, having a tensile strength of 885 MPa or more in a direction inclined at 45° to the rolling direction.

24. The copper alloy sheet according to claim 18, having an electrical conductivity of 35% IACS or more in a direction parallel to the rolling direction.

25. An electronic component comprising the copper alloy sheet according to any one of claims 1 to 24.

26. A method for manufacturing a copper alloy comprising the steps of: hot rolling an ingot of a copper alloy containing 1.5 to 4.5 mass% Ni, 0.10 to 1.2 mass% Si, with the balance being Cu and unavoidable impurities; solution treating the obtained copper alloy intermediate; cold rolling the copper alloy intermediate; aging the copper alloy intermediate; and finish cold rolling the copper alloy intermediate, in this order; and calculating an electrical conductivity (A (% IACS)), 0.2% proof stress (B (MPa)), tensile strength (C (MPa)), and plate thickness (D (mm)) of the copper alloy intermediate after the solution treating step by using the formula (X = (A 2 When (C×B) / (C×D)), the value of X in the formula is 500 or less.

27. The method for producing a copper alloy sheet according to claim 26, wherein the copper alloy sheet further contains 0.050 to 1.00 mass% in total of one or more elements selected from the group consisting of Mg, Fe, P, Mn, Co, Pb, Zn, and Cr.

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