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

Abstract

Provided are a copper alloy sheet that has improved strength and reduced surface roughness after etching, an electronic component, and a production method for the copper alloy sheet. A copper alloy sheet according to the present invention is 1.50–4.60 mass% Ni, 0.10–0.80 mass% Co, and 0.10–1.30 mass% Si, the remainder being Cu and unavoidable impurities. The arithmetic average height Sa of an etched surface that has been etched using a spray etching device to spray an etching liquid that is a mixed liquid that includes cupric chloride and hydrochloric acid at concentrations of 3 mol / L and 4 mol / L, respectively, for 75–80 seconds at an etching liquid temperature of 45°C–55°C and a spraying pressure of 0.08–0.12 MPa is no more than 0.390 μm, and the tensile strength in the direction parallel to a rolling direction is at least 840 MPa.

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. Corson alloys are used in electronic components because they have both high strength and high electrical conductivity. For example, they can be used as lead frames that support and fix semiconductor elements in semiconductor packages and form internal wiring (see, for example, Patent Documents 1 and 2).

[0003] JP 2018-035437 A JP 2017-179511 A

[0004] When copper alloys are used for lead frames or the like, microfabrication may be performed after etching. In this case, if the copper alloy surface has irregularities, this may hinder the microfabrication. The inventions described in Patent Documents 1 and 2 both aim to improve the strength and the surface smoothness of the etched surface, but there is still room for further improvement in terms of improving the strength and the surface smoothness of the etched surface.

[0005] In view of the above problems, the present invention provides a copper alloy sheet, an electronic component, and a method for manufacturing a copper alloy sheet, which have improved strength and reduced surface roughness after etching.

[0006] In order to solve the above problems, according to one embodiment of the present invention, there is provided a copper alloy sheet containing 1.50 to 4.60 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.30 mass% Si, with the remainder being Cu and inevitable impurities, wherein the copper alloy sheet is subjected to an etching treatment using a mixed liquid containing cupric chloride and hydrochloric acid at concentrations of 3 mol / L and 4 mol / L, respectively, as an etching solution, and sprayed with a spray etching device at an etching solution temperature of 45 to 55°C and a spray pressure of 0.08 to 0.12 MPa for 75 to 80 seconds, resulting in an arithmetic mean height Sa of an etched surface of 0.390 μm or less, and a tensile strength in a direction parallel to the rolling direction of 840 MPa or more.

[0007] According to another embodiment of the present invention, there is provided an electronic component comprising the above copper alloy sheet.

[0008] According to yet another embodiment of the present invention, there is provided a copper alloy manufacturing method comprising the steps of: hot rolling an ingot of a copper alloy containing 1.50 to 4.60 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.30 mass% Si, with the balance being Cu and inevitable impurities; solution treating the obtained copper alloy intermediate; aging the copper alloy intermediate; finish cold rolling the copper alloy intermediate; and stress relief annealing the copper alloy intermediate, wherein the tensile strength (A (MPa)) and electrical conductivity (B (% IACS)) of the copper alloy intermediate after the solution treating step and before the aging step satisfy the following relational expression (1): X=A 2 / B (1) The present invention provides a method for producing a copper alloy sheet, comprising producing a copper alloy intermediate so that the value of X represented by the following formula is 6700 or more and 17700 or less.

[0009] According to the present invention, it is possible to provide a copper alloy sheet, an electronic component, and a method for manufacturing a copper alloy sheet, which have improved strength and reduced surface roughness after etching.

[0010] FIG. 1 shows the relationship between the tensile strength (A) and electrical conductivity (B) of an intermediate copper alloy sheet after solution treatment, calculated by the formula (1): X = A 2 1 is a graph showing the relationship between X, which is represented by / B, and the arithmetic mean height Sa of the copper alloy plate after etching.

[0011] 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.

[0012] (Copper alloy sheet) The copper alloy sheet according to this embodiment is a copper alloy sheet containing 1.50 to 4.60 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.30 mass% Si, with the balance being Cu and inevitable impurities. That is, the copper alloy sheet according to this embodiment is a Cu—Ni—Co—Si based alloy sheet.

[0013] (Contents of Ni, Co, and Si) Ni, Co, and Si form precipitated particles of a Cu-Ni-Co-Si intermetallic compound by appropriate heat treatment, thereby improving the electrical conductivity, strength, and heat resistance of the copper alloy.

[0014] The greater the amount of Ni added, the higher the strength, but the lower the conductivity tends to be. If the Ni concentration is less than 1.50 mass%, the desired strength cannot be obtained. The Ni concentration is preferably 2.00 mass% or more, more preferably 2.30 mass% or more, even more preferably 3.00 mass% or more, and even more preferably 3.50 mass% or more. On the other hand, if the Ni concentration exceeds 4.60 mass%, the desired conductivity cannot be obtained. The Ni concentration is preferably 4.50 mass% or less, more preferably 4.30 mass% or less, even more preferably 4.00 mass% or less, and even more preferably 3.70 mass% or less. For example, the Ni concentration is preferably 2.30 to 4.60 mass%, preferably 3.00 to 4.00 mass%, and preferably 3.50 to 3.70 mass%.

[0015] If the Si concentration is less than 0.10 mass%, the desired strength cannot be obtained. The Si concentration is preferably 0.30 mass% or more, more preferably 0.50 mass% or more, even more preferably 0.70 mass% or more, and even more preferably 0.80 mass% or more. On the other hand, if the Si concentration exceeds 1.30 mass%, the desired conductivity cannot be obtained. The Si concentration is preferably 1.20 mass% or less, more preferably 1.10 mass% or less, even more preferably 1.00 mass% or less, and even more preferably 0.90 mass% or less. For example, the Si concentration is preferably 0.50 to 1.30 mass%, preferably 0.60 to 1.00 mass%, and preferably 0.70 to 0.90 mass%.

[0016] Co improves electrical conductivity and strength, and by adding an appropriate amount, it is possible to suppress a decrease in the heat resistance of the copper alloy sheet according to this embodiment, which is caused by short-time annealing when reducing residual stress after press working after press working the copper alloy sheet into a desired electronic component such as a lead frame. In order to obtain a copper alloy sheet that combines high electrical conductivity, high strength, and the effect of improving heat resistance against short-time annealing after working, the Co concentration is set to 0.10 mass% or more. The Co concentration is preferably 0.15 to 0.80 mass%, more preferably 0.15 to 0.75 mass%, even more preferably 0.20 to 0.70 mass%, and even more preferably 0.20 to 0.50 mass%.

[0017] (Ni + Co) If the content of Ni + Co is too small, the desired strength, electrical conductivity, and heat resistance to short-time annealing after heat treatment cannot be significantly improved, while if the amount of Ni + Co added is too large, workability deteriorates. The copper alloy sheet according to this embodiment preferably contains Ni and Co in total at 1.60 mass% or more, more preferably at 2.28 mass% or more, even more preferably at 3.00 mass% or more, and even more preferably at 3.50 mass% or more. On the other hand, the copper alloy sheet according to this embodiment preferably contains Ni and Co in total at 4.50 mass% or less, more preferably at 4.30 mass% or less, and even more preferably at 4.00 mass% or less.

[0018] ((Ni + Co) / Si mass ratio) Ni-Co-Si-based precipitates formed from 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 sheet become precipitates by the aging treatment during the manufacturing process of the copper alloy sheet, and some may exist in a solid solution state in the Cu matrix. Ni, Co, and Si in a solid solution state can improve the strength of the copper alloy sheet, but the effect is smaller than that in a precipitated state, and they may also be a factor in reducing the electrical conductivity. Therefore, it is preferable that the contents of Ni, Co, and Si are close to the composition ratio of (Ni + Co) Si. In the copper alloy sheet according to this embodiment, 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] (Additive elements) At least one element 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 (also referred to as "additive elements" in this specification) improves manufacturability by refining the ingot structure, such as improving hot workability, and also has the effect of improving the strength, electrical conductivity, and heat resistance of the copper alloy sheet. Therefore, by adding one or more of these additive elements according to the properties required of the copper alloy sheet according to this embodiment, further improvement in the properties of the copper alloy sheet can be expected.

[0020] The copper alloy sheet according to this embodiment preferably further contains 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 in a total amount of 0.01 to 2.00 mass%. The total content of the additional elements is preferably 0.03 to 1.00 mass%, more preferably 0.05 to 0.50 mass%.

[0021] (Cr Content) Among the additive elements, Cr precipitates alone or as a compound with Si in the copper matrix by appropriate heat treatment, improving hot rolling properties. It also has the effect of improving the strength and electrical conductivity of the copper alloy sheet according to this embodiment. On the other hand, if the Cr content exceeds 0.50 mass%, coarse inclusions that do not contribute to strengthening are formed, which may impair workability and surface smoothness after etching. The copper alloy sheet according to this embodiment can contain 0.005 to 0.50 mass%, preferably 0.01 to 0.50 mass%, more preferably 0.20 to 0.50 mass%, and even more preferably 0.20 to 0.30 mass% of Cr in the Cu-Ni-Co-Si alloy.

[0022] (Mg Content) Among the additive elements, when an appropriate amount of Mg is contained, it not only stably forms precipitated particles of Si contained in the copper alloy sheet according to this embodiment, but also has the effect of obtaining a copper alloy sheet that combines strength, electrical conductivity, and heat resistance. The copper alloy sheet according to this embodiment can contain 0.005 to 0.50 mass%, preferably 0.01 to 0.50 mass%, more preferably 0.05 to 0.50 mass%, and even more preferably 0.10 to 0.30 mass% of Mg in the Cu-Ni-Co-Si alloy.

[0023] The copper alloy sheet according to this embodiment is made up of Cu and inevitable impurities, the remainder being components other than those mentioned above. Here, the inevitable impurities refer to impurity elements that are unavoidably mixed into the copper alloy sheet during the manufacturing process. The concentration of each element of the inevitable impurities can be, for example, less than 0.001 mass%, and preferably 0% (undetectable).

[0024] The composition of the copper alloy can be measured using X-ray fluorescence analysis. The X-ray fluorescence analyzer used can be a Simultix 14 manufactured by Rigaku Corporation or an equivalent device. The analysis surface can be machined or mechanically polished so that the maximum surface roughness Rz (JIS B 0601:2013) is 6.3 μm or less. When collecting samples for X-ray fluorescence analysis from the molten metal during melting and casting, the sample is cast into a shape of approximately 30 to 40 mm diameter and 50 to 80 mm thick, then cut to a thickness of approximately 10 to 20 mm, and the cut surface is used as the analysis surface. X-ray fluorescence analysis is performed based on JIS K 0119:2008, and measurements are taken using a wavelength dispersive method.

[0025] The shape of the copper alloy sheet according to this embodiment is not particularly limited as long as it is a three-dimensional shape having a predetermined thickness. The "plate" of the copper alloy sheet also includes sheet, strip, and foil. Furthermore, the copper alloy sheet according to this embodiment includes not only copper alloy sheets before processing for use in electronic components, but also copper alloy sheets during or after processing. The thickness of the copper alloy sheet 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.

[0026] (Surface characteristics of etched surface) In the copper alloy sheet according to this embodiment, the arithmetic mean height Sa of the etched surface after a predetermined etching treatment is performed on the surface of the copper alloy sheet is 0.390 μm or less. This makes it possible to prevent peeling caused by large surface roughness when the copper alloy sheet according to this embodiment is bonded to a resin.

[0027] Copper alloy sheets are sometimes used as electronic components after etching and subsequent processing. Etching can increase the surface roughness of copper alloy sheets and potentially impair their surface smoothness. However, the copper alloy sheet according to this embodiment can achieve a low arithmetic mean height Sa even after etching, thereby maintaining high surface smoothness and high strength. Furthermore, electronic components such as lead frames have a predetermined area, and the copper alloy sheets used therefor must have controlled surface properties. During etching of a copper alloy sheet, the dissolution reaction proceeds preferentially from areas that are more reactive, potentially resulting in localized areas with large irregularities. According to this embodiment, to evaluate the surface properties of a copper alloy sheet, the arithmetic mean height Sa of the surface, rather than the arithmetic mean height Ra of the line, is focused on, and this value is adjusted to a suitable value. Therefore, the etched surface of the copper alloy sheet after etching has a surface smoothness particularly suitable for micromachining.

[0028] The arithmetic mean height Sa of the etched surface is preferably 0.354 μm or less, more preferably 0.330 μm or less, even more preferably 0.300 μm or less, even more preferably 0.250 μm or less, and even more preferably 0.220 μm or less. The lower limit of the arithmetic mean height Sa of the etched surface is not particularly limited, but may be, for example, 0.100 μm or more, or 0.185 μm or more.

[0029] The etched surface according to this embodiment refers to a treated surface obtained by an etching treatment in which a mixed solution containing cupric chloride and hydrochloric acid at concentrations of 3 mol / L and 4 mol / L, respectively, is used as an etching solution and the etching solution is sprayed using a spray etching device at an etching solution temperature of 45 to 55°C and a spray pressure of 0.08 to 0.12 MPa for 75 to 80 seconds. Typically, the etched surface according to this embodiment refers to a treated surface in which approximately 30 to 50 μm has been removed from the surface of the copper alloy plate in the thickness direction.

[0030] More specifically, a spray etching device manufactured by Sun Microsystems, Inc. or an equivalent device is used as the etching device. For example, 1 L of a mixed solution containing cupric chloride and hydrochloric acid at concentrations of 3 mol / L and 4 mol / L, respectively, is prepared as the etching solution. Other specific conditions for the etching process are as follows: Etching solution temperature: 50°C; Etching time: 77 seconds; Nozzle: Full cone type; Nozzle arrangement: 4 nozzles on the bottom only, 20 nozzles in total; Spray direction: Vertical; Spray pressure: 0.1 MPa; Copper alloy sheet feed rate: 0.7 m / min; Sample feed direction: Horizontal; Sample angle: Parallel to the horizontal direction. After etching, the copper alloy sheet is washed with running water and then dried with a dryer. To remove smut, the copper alloy sheet after drying is placed in a beaker containing 3% by mass hydrochloric acid and ultrasonically cleaned for 10 seconds, then washed with running water and dried with a dryer.

[0031] The arithmetic mean height Sa is measured in accordance with ISO 25178 under the following conditions. A laser microscope, such as a VK-X1050 manufactured by Keyence Corporation or an equivalent device, is used. Images of the etched surface of the copper alloy plate are taken using the laser microscope. The captured images are measured using analysis software for the laser microscope (VK-X1050 manufactured by Keyence Corporation). The measurement results are calculated by averaging values ​​measured at any four locations excluding the edge portion or areas where uneven etching occurs.

[0032] More specific measurement conditions for the arithmetic mean height Sa are as follows: Temperature during measurement: 20 to 25°C Magnification of objective lens: 50x Optical zoom magnification: 1x Pitch: 0.13 μm RPD: ON Captured image size [number of pixels]: 275 μm horizontal x 206 μm vertical [1024 x 768] Double scan: OFF γ coefficient: 0.45 Offset: 0% Filter type: Gaussian S-filter: None F-operation: None L-filter: None End effect correction: Enabled

[0033] According to the copper alloy sheet of this embodiment, even when the surface of the copper alloy sheet is etched when the copper alloy sheet is processed into electronic components such as lead frames, the surface smoothness of the etched surface after the etching treatment can be improved. This makes it possible to accurately form fine and complex patterns on the copper alloy sheet depending on the processing purpose.

[0034] (Tensile Strength) The copper alloy sheet according to this embodiment has a tensile strength of 840 MPa or more in a direction parallel to the rolling direction. Having a tensile strength of 840 MPa or more can suppress deformation of the copper alloy sheet when electronic components are manufactured using the copper alloy sheet. The copper alloy sheet according to this embodiment preferably has a tensile strength of 900 MPa or more in a direction parallel to the rolling direction, more preferably 925 MPa or more, and even more preferably 937 MPa or more. The upper limit of the tensile strength in the direction parallel 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 of the copper alloy sheet can be measured in accordance with JIS Z 2241:2011 by the method described in the Examples section below. The tensile strength can be adjusted to a desired range by controlling the composition of the copper alloy sheet within the above range and manufacturing it using the manufacturing method described below.

[0035] (0.2% Yield Strength) The copper alloy sheet according to this embodiment may have a 0.2% yield strength of 850 MPa or more in a direction parallel to the rolling direction. This makes it possible to more effectively suppress deformation of the copper alloy sheet during the manufacture of electronic components. The 0.2% yield strength in a direction parallel to the rolling direction is preferably 900 MPa or more, more preferably 936 MPa or more, and even more preferably 950 MPa or more. The upper limit of the 0.2% yield strength in a direction parallel to the rolling direction is not particularly limited, but the 0.2% yield strength may be, for example, 1200 MPa or less or 1100 MPa or less. The 0.2% yield strength can be measured in accordance with JIS Z 2241:2011 by the method described in the Examples section below.

[0036] (Electrical Conductivity) The copper alloy sheet according to this embodiment may have an electrical conductivity of 35.0% IACS or more. With an electrical conductivity of 35.0% IACS or more, the copper alloy sheet can be effectively used as a copper alloy part for electronic components. The electrical conductivity in a direction parallel to the rolling direction is preferably 37.0% IACS or more, more preferably 40.0% IACS or more, even more preferably 40.2% IACS or more, and still more preferably 41.0% IACS or more. The upper limit of the electrical conductivity is not particularly limited, but may be, for example, 90.0% IACS or less, or 80.0% IACS or less.

[0037] The electrical conductivity can be measured by a four-terminal method in accordance with JIS H 0505:1975. A double bridge is used for the measurement, and the resistance can be measured based on the average cross-sectional area method. The electrical conductivity can be measured at room temperature (25°C) in a direction parallel to the rolling direction. The gauge length (distance between electrical resistance measurements) can be 50 mm. Hereinafter, a method for producing a copper alloy sheet according to this embodiment will be described.

[0038] (Method for manufacturing copper alloy sheet) Hereinafter, a method for manufacturing a copper alloy sheet according to this embodiment will be described. The method for manufacturing a copper alloy sheet according to this embodiment includes the steps of hot rolling an ingot of a copper alloy containing 1.50 to 4.60 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.30 mass% Si, with the balance being Cu and inevitable impurities, solution treating the obtained copper alloy intermediate, aging the copper alloy intermediate, finish cold rolling the copper alloy intermediate, and stress relief annealing the copper alloy intermediate, in this order, and the tensile strength (A (MPa)) and electrical conductivity (B (% IACS)) of the copper alloy intermediate after the solution treating step and before the aging step satisfy the following relational expression (1): X=A 2 / B (1) The present invention also includes producing a copper alloy intermediate so that the value of X represented by the following formula is 6700 or more and 17700 or less.

[0039] According to the method for producing a copper alloy plate according to this embodiment, attention is paid to the etching characteristics during processing of the copper alloy plate, and the value of X in formula (1) is adjusted to be 6700 or more and 17700 or less during the production of a copper alloy intermediate. This makes it possible to reduce the value of the arithmetic mean height Sa of the etched surface while maintaining high strength even in the etching treatment before processing the copper alloy plate, and improve the surface smoothness, so that a desired shape can be formed with high precision even in micromachining, etc.

[0040] More specifically, the copper alloy sheet according to this embodiment can be manufactured by the following method. First, a step of melting and casting a copper alloy raw material having the desired composition described above is performed. In this step, the copper alloy raw material is melted using a method similar to that of a general copper alloy melting method, and then an ingot is manufactured by continuous casting, semi-continuous casting, or the like. That is, an atmospheric melting furnace is used to melt raw materials such as electrolytic copper, Ni, Co, and Si to obtain a molten metal with the desired composition. This molten metal is then poured into a mold of any desired size to cast an ingot. Thereafter, homogenization annealing is performed at 800 to 1000°C, and further hot rolling is performed.

[0041] Hot rolling is performed in several passes at, for example, 500 to 950°C. The total reduction ratio of the hot rolling is preferably 90% or more. The reduction ratio (%) of the rolling is expressed as reduction ratio (%) = [(TB - TA) / TB] x 100, where TB is the thickness of the workpiece before rolling and TA is the thickness of the workpiece after rolling.

[0042] In the solution treatment after hot rolling, silicides (silicides) such as Ni-Si compounds, Co-Si compounds, and Cr-Si compounds are dissolved in the Cu matrix, and at the same time, heat treatment is performed to recrystallize the Cu matrix. In the method for producing a copper alloy sheet according to this embodiment, by adjusting the value of X represented by the above formula (1) for the copper alloy intermediate after the solution treatment to be 6700 or more and 17700 or less, a copper alloy sheet and electronic parts having excellent properties in terms of strength, electrical conductivity, and yield strength and reduced surface roughness after etching can be obtained.

[0043] The value of X represented by formula (1) is preferably 15,000 or less, more preferably 14,000 or less, and even more preferably 10,000 or less. On the other hand, by setting the lower limit of X to 6,700 or more, it is possible to dissolve the Ni-Co-Si compound in the Cu matrix and simultaneously recrystallize the Cu matrix, and precipitates that contribute to strength during aging treatment are precipitated, thereby increasing the tensile strength after stress relief annealing. The lower limit of X is more preferably 7,000 or more, and even more preferably 8,000 or more.

[0044] 1 is a graph showing the relationship between X in the above formula (1) and the arithmetic mean height Sa (μm) of the etched surface after etching the surface of the copper alloy sheet according to this embodiment under the above conditions. Here, the tensile strength (A) and the electrical conductivity (B) are both values ​​obtained by measurement in a direction parallel to the rolling direction. By setting the value of X in formula (1) to 17,700 or less, it becomes easy to produce a copper alloy sheet having excellent surface smoothness and an arithmetic mean height Sa of 0.390 μm or less. Note that the values ​​of the tensile strength (A (MPa)) and electrical conductivity (B (% IACS)) of the copper alloy intermediate after solution treatment in the above formula (1) can be measured by the method described in the Examples section below.

[0045] The heating temperature for the solution treatment can be appropriately selected from the range of, for example, 800 to 1100°C. The heating time can be appropriately selected from the range of 1 second to 10 minutes. The value of X in formula (1) can be reduced by relatively lowering the heating temperature for the solution treatment and relatively shortening the heating time. That is, by appropriately selecting and combining the heating temperature and heating time for the solution treatment, the value of X can be set to 6700 or more and 17700 or less, and the Ni-Co-Si compound can be solid-dissolved in the Cu matrix, while simultaneously recrystallizing the Cu matrix. This allows precipitates that contribute to strength to be precipitated during aging treatment, and this can increase the tensile strength after stress relief annealing and improve the surface smoothness of the etched surface after etching.

[0046] The heating temperature for the solution treatment may be 850 to 1090° C., or may be 900 to 1000° C. The material temperature may be appropriately selected, for example, from the range of 750 to 1000° C. The heating time may be 5 seconds to 1 minute, or may be 10 seconds to 30 seconds.

[0047] The heating temperature of the aging treatment of the copper alloy intermediate after the solution treatment is not particularly limited, but may be, for example, 300 to 625°C, 400 to 550°C, or 450 to 500°C. The heating time of the aging treatment may be 1 to 50 hours, 1.5 to 25 hours, or 10 to 15 hours. By appropriately adjusting the heating temperature and heating time of the aging treatment, a sufficient amount of Ni-Co-Si-based compounds precipitates, making it easier to obtain the desired strength. Furthermore, by appropriately adjusting the heating temperature and heating time of the aging treatment within the above ranges, coarsening of precipitates and re-dissolution can be prevented, making it easier to improve strength and electrical conductivity, and also improving surface smoothness after etching. The aging treatment is preferably performed in an inert atmosphere such as Ar, N, or H to suppress the formation of an oxide film.

[0048] The finish cold rolling may be performed in several passes. The total working ratio of the finish cold rolling may be 35% or more. This allows the copper alloy intermediate to be subjected to working strain and to have improved strength. In particular, the strength in a direction inclined relative to the rolling direction is more likely to be improved by increasing the total working ratio of the finish cold rolling as the inclination angle increases. Therefore, by setting the working ratio to 35% or more, the strength in various directions relative to the rolling direction can be improved.

[0049] The reduction ratio of the finish cold rolling is preferably 55% or more, more preferably 60% or more, and even more preferably 70% or more. The reduction ratio of the finish cold rolling may be 90% or less. This prevents a decrease in electrical conductivity due to processing strain caused by a high reduction ratio.

[0050] After the finish cold rolling, a step of performing stress relief annealing may be included. The heating temperature of stress relief annealing may be, for example, 300 to 600°C, and preferably 305 to 570°C. The heating time of stress relief annealing may be, for example, 5 to 900 seconds, 60 to 600 seconds, or 250 to 650 seconds. Stress relief annealing may be performed in air or in an inert atmosphere such as nitrogen or argon gas. Furthermore, the copper alloy sheet after stress relief annealing may be cooled by air cooling.

[0051] In the method for producing a copper alloy sheet according to this embodiment, cold rolling may be performed before the solution treatment, or after the solution treatment but before the aging treatment, or the solution treatment and the aging treatment may each be performed two or more times. Furthermore, after each of the above production steps, grinding, pickling, polishing, degreasing, facing, shot blasting, trimming, etc. may be appropriately performed as necessary to remove oxide scale from the surface.

[0052] Furthermore, the method for manufacturing a copper alloy sheet according to this embodiment may further include a step of etching the copper alloy sheet after the stress relief annealing step. The copper alloy sheet subjected to this etching step after the stress relief annealing step has high strength and small surface roughness of the etched surface, so that the copper alloy sheet can be subjected to fine processing according to the processing purpose. Furthermore, when this copper alloy sheet is bonded to a resin or the like, peeling due to the surface roughness can be significantly suppressed.

[0053] The specific conditions for this etching step are not particularly limited, but for example, a mixed solution containing cupric chloride and hydrochloric acid at concentrations of 3 mol / L and 4 mol / L, respectively, can be used as the etching solution. This step can be performed using a spray etching device, where the etching solution is sprayed at an etching solution temperature of 45 to 55°C and a spray pressure of 0.08 to 0.12 MPa for 75 to 80 seconds. The arithmetic mean height Sa of the etched surface obtained by this etching process is 0.390 μm or less, and the tensile strength in the direction parallel to the rolling direction is 840 MPa or more.

[0054] (Electronic component) The electronic component according to this embodiment is an electronic component comprising the copper alloy sheet according to this embodiment. More specifically, the electronic component according to this embodiment comprises a copper alloy part manufactured from the above-mentioned copper alloy sheet. An example of the electronic component is a semiconductor package. The miniaturized copper alloy part that can be manufactured from the copper alloy sheet according to this embodiment has reduced surface roughness after processing in the manufacturing process of the electronic component, so it is suitable to use the copper alloy sheet according to this embodiment for manufacturing a semiconductor package having many miniaturized structures.

[0055] When the electronic component is a semiconductor package, the semiconductor package can be manufactured, for example, without being particularly limited thereto, by manufacturing a lead frame using the copper alloy sheet according to 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 then sealing 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-mentioned embodiment.

[0056] 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.

[0057] A first aspect of the present disclosure is a copper alloy sheet containing 1.50 to 4.60 mass % Ni, 0.10 to 0.80 mass % Co, 0.10 to 1.30 mass % Si, with the remainder being Cu and unavoidable impurities, the copper alloy sheet being subjected to an etching treatment using a mixed liquid containing cupric chloride and hydrochloric acid at concentrations of 3 mol / L and 4 mol / L, respectively, as an etching solution, and spraying the etching solution using a spray etching device at an etching solution temperature of 45 to 55°C and a spray pressure of 0.08 to 0.12 MPa for 75 to 80 seconds, the copper alloy sheet having an arithmetic mean height Sa of an etched surface of 0.390 μm or less, and a tensile strength in a direction parallel to the rolling direction of 840 MPa or more.

[0058] A second aspect of the present disclosure is the copper alloy sheet according to the first aspect, further containing 0.01 to 2.00 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.

[0059] A third aspect of the present disclosure is the copper alloy sheet according to the first or second aspect, further containing 0.01 to 0.50 mass% of Cr.

[0060] A fourth aspect of the present disclosure is the copper alloy sheet according to any one of the first to third aspects, containing 0.20 to 0.50 mass% Co.

[0061] A fifth aspect of the present disclosure is the copper alloy sheet according to any one of the first to fourth aspects, wherein the arithmetic mean height Sa is 0.185 μm or more.

[0062] A sixth aspect of the present disclosure is the copper alloy sheet according to any one of the first to fifth aspects, wherein the arithmetic mean height Sa is 0.354 μm or less.

[0063] A seventh aspect of the present disclosure is the copper alloy sheet according to any one of the first to sixth aspects, wherein the tensile strength in a direction parallel to the rolling direction is 900 MPa or more.

[0064] 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 parallel to the rolling direction is 937 MPa or more.

[0065] A ninth aspect of the present disclosure is the copper alloy sheet according to any one of the first to eighth aspects, having a conductivity of 35.0% IACS or more.

[0066] A tenth aspect of the present disclosure is the copper alloy sheet according to any one of the first to ninth aspects, having a conductivity of 40.2% IACS or more.

[0067] An eleventh aspect of the present disclosure is an electronic component including the copper alloy plate according to any one of the first to tenth aspects.

[0068] A twelfth aspect of the present disclosure is a copper alloy manufacturing method comprising the steps of: hot-rolling an ingot of a copper alloy containing 1.50 to 4.60 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.30 mass% Si, with the balance being Cu and inevitable impurities; solution-treating the obtained copper alloy intermediate; aging-treating the copper alloy intermediate; finish-cold-rolling the copper alloy intermediate; and stress-relief annealing the copper alloy intermediate, in this order; wherein the tensile strength (A (MPa)) and electrical conductivity (B (% IACS)) of the copper alloy intermediate after the solution-treating step and before the aging step satisfy the following relational formula (1): X=A 2 / B (1) The present invention provides a method for producing a copper alloy sheet, comprising producing a copper alloy intermediate so that the value of X represented by the following formula is 6700 or more and 17700 or less.

[0069] A thirteenth aspect of the present disclosure is the method for producing a copper alloy sheet according to the twelfth aspect, including a step of etching the copper alloy sheet after the stress relief annealing step.

[0070] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to the following examples in any way.

[0071] Using electrolytic copper as a raw material, copper alloys of Examples 1 to 9 and Comparative Examples 1 to 3 having the compositions shown in Table 1 were melted and cast using an atmospheric melting furnace. The resulting ingots were subjected to homogenization annealing at 980°C for 3 hours. Next, hot rolling was performed to a plate thickness of 10 mm, followed by facing. Subsequently, solution treatment was performed under the conditions shown in Table 1. The copper alloy intermediates, whose X values ​​after solution treatment were the values ​​shown in Table 1, were subjected to aging treatment at 400 to 550°C for 1.5 to 25 hours. The resulting copper alloy intermediates were pickled and polished, and then subjected to finish cold rolling treatment to a plate thickness of 0.151 mm with the working ratio shown in Table 1. The copper alloy intermediates after the finish cold rolling treatment were further subjected to stress relief annealing at 300 to 600°C for 60 to 600 seconds in the atmosphere. The copper alloy sheets after stress relief annealing were air-cooled to obtain the copper alloy sheets of Examples 1 to 9 and Comparative Examples 1 to 3.

[0072]

[0073] The physical properties of the obtained copper alloy sheets of Examples 1 to 9 and Comparative Examples 1 to 3 were measured by the following methods. The results are shown in Table 2.

[0074] (Composition) The compositions of the obtained copper alloys were confirmed by X-ray fluorescence analysis. A Simultix 14 manufactured by Rigaku Corporation was used as the X-ray fluorescence analyzer. The copper alloy sheets of Example 1 and Comparative Example 1 were cut or mechanically polished to have a maximum surface roughness Rz (JIS B 0601:2013) of 6.3 μm or less, and the analysis surfaces were used. X-ray fluorescence analysis was performed based on JIS K 0119:2008, and measurements were made using a wavelength dispersive method.

[0075] (Tensile Strength) The tensile strength in the direction parallel to the rolling direction was measured using a tensile testing machine (Autocom AC-100KN-C, manufactured by TSE Co., Ltd.) in accordance with JIS Z 2241:2011. Specifically, a JIS Z 2241 No. 13B test piece was prepared from each sample using a press so that the tensile direction was parallel to the rolling direction. The tensile test conditions were as follows: test piece width: 12.5 mm, measurement temperature: room temperature (15 to 35°C), tensile speed (crosshead displacement speed): 5 mm / min, and gauge length (gauge length): 50 mm. The test was performed using two test pieces, and the average of the two data was calculated.

[0076] (0.2% Proof Stress) The 0.2% proof stress in the direction parallel to the rolling direction was measured using a tensile testing machine (Autocom AC-100KN-C, manufactured by TSE Co., Ltd.) in accordance with JIS Z 2241:2011 (offset method, 0.2%). Specifically, test pieces were prepared in the same manner as for the tensile strength described above, and tests were conducted under the same conditions as for the tensile strength described above.

[0077] (Conductivity) The conductivity was measured by a four-terminal method in accordance with JIS H 0505:1975. 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) in a direction parallel to the rolling direction. The gage length (distance between electrical resistance measurements) was 50 mm.

[0078] (Arithmetic mean height Sa after etching) Using the copper alloy sheets of Examples 1 to 9 and Comparative Examples 1 to 3, etching was performed by the above-mentioned method, and then the arithmetic mean height Sa of the surface (etched surface) of the copper alloy sheet after etching was measured. The results are shown in Table 2.

[0079]

[0080] According to Examples 1 to 9, copper alloy sheets having higher strength and reduced roughness after etching can be obtained compared to Comparative Examples 1 to 3.

[0081] (Potential Contribution to SDGs) According to one embodiment of the present disclosure, a copper alloy sheet having excellent heat resistance and high strength even after annealing, and an electronic component including the same, can be provided, which may contribute to improving the operational stability and reliability of electronic devices. Therefore, one embodiment of the present disclosure may contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation."

Claims

1. A copper alloy sheet containing 1.50 to 4.60 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.30 mass% Si, with the remainder being Cu and unavoidable impurities, wherein the copper alloy sheet is etched using a mixed solution containing cupric chloride and hydrochloric acid at concentrations of 3 mol / L and 4 mol / L, respectively, and is subjected to an etching treatment using a spray etching device at an etching solution temperature of 45 to 55°C and a spray pressure of 0.08 to 0.12 MPa for 75 to 80 seconds, resulting in an arithmetic mean height Sa of the etched surface of 0.390 μm or less, and a tensile strength in a direction parallel to the rolling direction of 840 MPa or more.

2. The copper alloy sheet according to claim 1, further containing 0.01 to 2.00 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 0.01 to 0.50 mass% of Cr.

4. The copper alloy sheet according to claim 1, containing 0.20 to 0.50 mass % Co.

5. The copper alloy sheet according to claim 1, wherein the arithmetic mean height Sa is 0.185 μm or more.

6. The copper alloy sheet according to claim 5, wherein the arithmetic mean height Sa is 0.354 μm or less.

7. The copper alloy sheet according to claim 1, having a tensile strength of 900 MPa or more in a direction parallel to the rolling direction.

8. The copper alloy sheet according to claim 1, having a tensile strength of 937 MPa or more in a direction parallel to the rolling direction.

9. The copper alloy sheet according to claim 1, having an electrical conductivity of 35.0% IACS or more.

10. The copper alloy sheet according to claim 1, having an electrical conductivity of 40.2% IACS or more.

11. An electronic component comprising the copper alloy sheet according to any one of claims 1 to 10.

12. A copper alloy manufacturing method comprising the steps of: hot rolling an ingot of a copper alloy containing 1.50 to 4.60 mass% Ni, 0.10 to 0.80 mass% Co, 0.10 to 1.30 mass% Si, with the balance being Cu and unavoidable impurities; solution treating the obtained copper alloy intermediate; aging the copper alloy intermediate; finish cold rolling the copper alloy intermediate; and stress relief annealing the copper alloy intermediate, in this order; wherein the tensile strength (A (MPa)) and electrical conductivity (B (% IACS)) of the copper alloy intermediate after the solution treating step and before the aging step satisfy the following relationship (1): X=A 2 / B (1) wherein the value of X is 6700 or more and 17700 or less.

13. The method for producing a copper alloy sheet according to claim 12, further comprising a step of etching the copper alloy sheet after the stress relief annealing step.

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