copper alloy plate

Abstract

To provide a copper alloy sheet having sufficient levels of hardness and conductivity.SOLUTION: A copper alloy sheet contains Ni: 0.6-1.0 mass%, Fe: 0.05-0.20 mass%, P: 0.06-0.15 mass%, Sn: 1.0-2.2 mass%, with the balance being copper and unavoidable impurities, and exhibits a Vickers hardness of 250 HV or more and a conductivity of 25%IACS or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a copper alloy plate.

Background Art

[0002] In recent years, in products such as those in the electrical and electronic fields and the automotive field (for example, materials for semiconductors (lead frames, etc.), materials for heat dissipation members, materials for electrical and electronic components, and materials for electrical circuits, etc.), there are demands for resource conservation, high functionality, and miniaturization. Along with this, the copper alloy plates used in such products are being thinned.

[0003] When the copper alloy plate is thinned, deformation of the copper alloy plate is likely to occur due to external forces generated in the manufacturing process and the usage environment of the product using the copper alloy plate. Therefore, in order to increase the resistance to deformation, the copper alloy plate is mainly required to have improved hardness.

[0004] Patent Document 1 describes that by controlling the content components such as Ni, Fe, P, Zn, etc., a copper alloy excellent in strength and conductivity can be provided.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] One aspect of the present invention is: The component composition is, Ni: 0.6~1.0% by mass, Fe:0.05~0.20% by mass, P:0.06~0.15% by mass, Sn: 1.0~2.2 mass%, and The remainder consists of copper and unavoidable impurities. The Vickers hardness is 250 HV or higher. This is a copper alloy plate with an electrical conductivity of 25% IACS or higher.

[0009] Aspect 2 of the present invention is, The copper alloy plate according to Embodiment 1 further contains Zn: 0.05 to 0.20 mass%.

[0010] A third aspect of the present invention is: The copper alloy sheet according to embodiment 1 or 2, wherein the Young's modulus in the direction perpendicular to both the rolling direction and the thickness direction is 140 GPa or more.

[0011] Aspect 4 of the present invention is A copper alloy sheet according to any one of embodiments 1 to 3, wherein the 0.2% yield strength in the direction perpendicular to both the rolling direction and the thickness direction is 890 MPa or more.

[0012] Aspect 5 of the present invention is A copper alloy plate according to any one of embodiments 1 to 4, wherein a plate material is cut out having a length of 60 mm in the rolling direction and a length of 6 mm in the direction perpendicular to both the rolling direction and the thickness direction, and when one surface of the plate material perpendicular to the thickness direction is etched until the thickness is reduced to 60%, the maximum height of the warp is 7.0 times or less the thickness of the plate before etching.

[0013] Aspect 6 of the present invention is, A copper alloy plate according to any one of embodiments 1 to 5, wherein the surface, after being etched for 130 seconds by immersion in a copper etching solution containing sulfuric acid: 24% by mass, hydrogen peroxide: less than 5% by mass, ethylene glycol: less than 3% by mass, and water at a temperature of 40 to 50°C, washed by immersion in water, and dried, is subjected to SEM-EDX analysis at an accelerating voltage of 15kV, and the peak height of the copper element is the largest among all elements. [Effects of the Invention]

[0014] According to embodiments of the present invention, it is possible to provide a copper alloy plate having sufficient hardness and sufficient conductivity. [Modes for carrying out the invention]

[0015] The inventors investigated from various angles to realize a copper alloy plate with sufficient hardness and sufficient conductivity. Their research revealed that, for example, with the miniaturization, thinning, and increased pin count of recent products (such as semiconductor lead frames), there is a growing need for copper alloy plates with a hardness of 250 HV or higher. Furthermore, with the decreasing signal strength of recent products, it was found that such products can be adequately designed even using copper alloy plates with conductivity of approximately 25% IACS.

[0016] The inventors have found that in order to realize a copper alloy sheet having a sufficient hardness of 250 HV or higher and a sufficient electrical conductivity of 25% IACS or higher, it is necessary to control the content of specific elements (especially Sn content) within a predetermined range, as well as to appropriately control the manufacturing conditions (in particular, the annealing conditions and the subsequent cold rolling conditions). The details of each requirement defined in the embodiments of the present invention are shown below. In the embodiments of the present invention, the term "copper alloy plate" is used to include copper alloy strips.

[0017] <1. Ingredient composition> The copper alloy sheet according to an embodiment of the present invention preferably has a component composition including Ni: 0.6 to 1.0% by mass, Fe: 0.05 to 0.20% by mass, P: 0.06 to 0.15% by mass, Sn: 1.0 to 2.2% by mass, and the balance being copper and unavoidable impurities. Hereinafter, each element will be described in detail.

[0018] <Ni: 0.6 to 1.0% by mass> Ni is an element that forms an intermetallic compound by combining with Fe and / or P, thereby improving the hardness and heat resistance of the copper alloy sheet. The Ni content is set to 0.6% by mass or more in order to obtain sufficient hardness. On the other hand, when the Ni content becomes excessive, the hot workability can be extremely reduced, so it is set to 1.0% by mass or less.

[0019] <Fe: 0.05 to 0.20% by mass> Fe is an element that forms an intermetallic compound by combining with Ni and / or P, thereby improving the hardness and heat resistance of the copper alloy sheet. The Fe content is set to 0.05% by mass or more in order to obtain sufficient hardness. On the other hand, when the Fe content becomes excessive, the precipitation of the Fe-P compound becomes prioritized and the amount of the compound becomes excessive, which may cause problems such as a decrease in strength and heat resistance, and further promotion of internal oxidation. Therefore, the Fe content is set to 0.20% by mass or less.

[0020] <P: 0.06 to 0.15% by mass> P is an element that precipitates an intermetallic compound by combining with Ni and / or Fe, thereby improving the hardness and heat resistance of the copper alloy sheet. The P content is set to 0.06% by mass or more in order to obtain sufficient hardness. On the other hand, when the P content becomes excessive, the hot workability decreases, so it is set to 0.15% by mass or less.

[0021] <Sn: 1.0 to 2.2% by mass> Sn is an element that improves mechanical properties such as hardness by solid solution in the metal structure. The Sn content should be 1.0 mass% or more to obtain sufficient hardness. The Sn content is preferably 1.5 mass% or more, more preferably 2.0 mass% or more. On the other hand, Sn is a relatively expensive metal, and from the perspective of cost, the Sn content should be 2.2 mass% or less.

[0022] The copper alloy plate according to an embodiment of the present invention contains the above component composition. In one embodiment of the present invention, the balance is preferably copper and unavoidable impurities. As unavoidable impurities, the inclusion of elements brought in according to the situations of raw materials, materials, manufacturing equipment, etc. is allowed. Examples of unavoidable impurities include Si, etc., and it is preferably 0.01 mass% or less in single form. Also, the total amount of unavoidable impurities is preferably 0.10 mass% or less, more preferably 0.03 mass% or less.

[0023] <Zn: 0.05 - 0.20 mass%> Furthermore, the copper alloy plate according to an embodiment of the present invention may contain Zn as required. Zn has the effects of reducing the wear of the press die, preventing migration, and improving the heat-resistant peelability of solder and Sn plating, and can increase the design freedom for materials for semiconductors (such as lead frames), materials for heat dissipation members, electrical and electronic components, and materials for electrical circuits, etc. In order to effectively exhibit these effects, the Zn content is preferably 0.05 mass% or more. On the other hand, when the Zn content is excessive, the conductivity and solder wetting property may decrease, so it is preferably 0.20 mass% or less.

[0024] <2. Vickers hardness> The copper alloy plate according to an embodiment of the present invention has the above component composition and can be made to have a Vickers hardness of 250 HV or more by manufacturing with a manufacturing method as described later. The Vickers hardness is a main index of the resistance to deformation by external force, and when the Vickers hardness is 250 HV or more, it can be applied to products such as recent semiconductor lead frames. Vickers hardness can be measured using a micro-Vickers hardness tester, applying a load of 1 kg to one surface of a copper alloy plate perpendicular to its thickness.

[0025] <3. Conductivity> The copper alloy plate according to the embodiment of the present invention has the above-described component composition and, by manufacturing it using the manufacturing method described later, can achieve an conductivity of 25%IACS or higher. A conductivity of 25%IACS or higher makes it applicable to products such as semiconductor lead frames. Furthermore, conductivity is also an indicator of heat dissipation, and a conductivity of 25%IACS or higher makes it applicable to heat dissipation components. Note that "%IACS" is the international standard for soft copper (resistivity 1.7241 × 10⁻¹⁰). -8 This index is defined as having a conductivity of Ωm as 100%. In embodiments of the present invention, resistivity can be measured using, for example, a double-bridge type resistance measuring device, and conductivity (%IACS) is obtained by dividing the resistivity of standard copper at 20°C by the resistivity of the sample being measured and expressing it as a percentage.

[0026] <4. Young's modulus> While the Young's modulus of general copper alloys is around 120 GPa, the copper alloy sheet according to the embodiment of the present invention can achieve a Young's modulus exceeding that. Specifically, the copper alloy sheet according to the embodiment of the present invention has a Young's modulus of preferably 140 GPa or more, and more preferably 150 GPa or more, in the direction perpendicular to both the rolling direction and the thickness direction (hereinafter also simply referred to as the "perpendicular direction"). Having such a Young's modulus allows for increased resistance to deformation due to external forces. The Young's modulus can be determined from the results of a tensile test.

[0027] <5.0.2% yield strength> In the embodiment of the present invention, the copper alloy plate preferably has a 0.2% yield strength in the perpendicular direction of 890 MPa or higher. This further increases the resistance to deformation due to external forces. The 0.2% yield strength can be determined from the results of a tensile test.

[0028] <6. Maximum height of warping after etching (half-etchability)> In recent years, when manufacturing products such as semiconductor lead frames, a process called half-etching, in which approximately half of the plate thickness is dissolved by chemicals (etching), has been widely applied to solve design constraints associated with miniaturization, thinning, and narrowing of the plate pitch. After half-etching, warping may occur, and the smaller the warping, the better the shape accuracy of the product. When evaluating warpage during half-etching, it is preferable to etch up to 60% of the plate thickness and then evaluate, taking into account variations in the accuracy of the plate thickness dissolved during etching. In practice, copper alloy plates with a warpage height after etching of approximately 7.0 times or less of the plate thickness before etching are widely used as they exhibit excellent half-etchability. In view of the above, in the embodiment of the present invention, it is preferable that the maximum height of the warp when a sheet of copper alloy material is cut from the center in the perpendicular direction, with dimensions of 60 mm in the rolling direction and 6 mm in the perpendicular direction, and one surface perpendicular to the thickness direction of the sheet material is etched until the thickness is reduced to 60%, is 7.0 times or less the original (before etching) thickness. Here, after etching, warping may occur such that the etched surface becomes concave, and the warp height can be determined as the maximum height from the plane when the copper alloy plate is placed on a plane with the etched surface facing downwards (the convex surface facing upwards). An aqueous nitric acid solution (nitric acid concentration 58%) can be used as the etching solution.

[0029] <7. Elements showing the highest peak height in SEM-EDX analysis after etching> If insoluble precipitates are dispersed within a copper alloy plate, after etching, precipitates called smut may remain on the surface or become mixed into the etching solution. In such cases, there is a risk of contaminating the product and manufacturing equipment. In particular, Cu-Ni-Si alloys, which are widely used as high-strength copper alloys, tend to leave a large amount of Ni-Si smut after etching. To suppress contamination of products and manufacturing equipment, it is preferable that the etched surface has a high concentration of copper, the main component. Specifically, it is preferable that when the surface is etched for 130 seconds by immersion in a general-purpose copper etching solution (Mitsubishi Gas Chemical Co., Ltd., Clean Etch CPB50, composed of sulfuric acid: 24% by mass, hydrogen peroxide: less than 5% by mass, ethylene glycol: less than 3% by mass, and water) at 40-50°C, washed by immersion in water, and dried, SEM-EDX analysis is performed on the surface with an accelerating voltage of 15kV, the peak height of the copper element is the highest among all elements.

[0030] <8. Manufacturing method> An example of a method for manufacturing a copper alloy plate according to an embodiment of the present invention is: (A) A step of melting a copper alloy having the above component composition at 1100°C or higher and casting it to prepare a copper alloy ingot, (B) A step of uniformly heating the copper alloy ingot at a heating temperature of 850°C or higher and holding time of 10 minutes or more, (C) A step of obtaining a copper alloy sheet by hot rolling the heat-treated copper alloy ingot, (D) A step of cooling the hot-rolled copper alloy sheet, (E) The cooled copper alloy plate is annealed at a heating temperature of 300 to 500°C and a holding time of 30 minutes to 24 hours. (F) The process includes cold rolling the annealed copper alloy sheet so that its Vickers hardness is 250 HV or higher. The above manufacturing method makes it possible to produce copper alloy sheets with sufficient hardness and conductivity. Furthermore, the above manufacturing method makes it possible to produce copper alloy sheets in which the Young's modulus in the perpendicular direction is 140 GPa or higher, the 0.2% yield strength is 890 MPa or higher, and the SEM-EDX maximum peak element after etching is copper. Furthermore, by including the following step (G) in addition to the above steps (A) to (F), it is possible to manufacture a copper alloy sheet in which the maximum height of the warpage after etching until the sheet thickness is reduced to 60% is 7.0 times or less the sheet thickness before etching. (G) A process of performing stress-relieving annealing on the cold-rolled copper alloy sheet. The following details each step.

[0031] (A) Process of preparing copper alloy ingots First, a copper alloy adjusted to the above-mentioned component composition is melted and cast to prepare a copper alloy ingot. The melting temperature is set to 1100°C or higher, taking into consideration the above-mentioned component composition. The molten metal is poured into a mold and cooled to obtain a copper alloy ingot. Cooling is preferably performed by circulating cooling water in the mold and by direct water cooling.

[0032] (B) Soaking process After step (A), the copper alloy ingot is subjected to a soaking treatment. Considering the above component composition, the heating temperature during the soaking treatment shall be 850°C or higher, and the holding time shall be 10 minutes or higher.

[0033] (C) Hot rolling process After step (B), the copper alloy ingot is hot-rolled to obtain a copper alloy sheet. It is preferable to complete the hot rolling at 650°C or higher. The sheet thickness after hot rolling can be set appropriately within a range that satisfies the aforementioned hot rolling completion temperature, and taking into consideration the final sheet thickness of the copper alloy sheet (not particularly limited, but for example, it may be 0.03 to 0.30 mm) and the processing rate of the cold rolling described later, but it can usually be set to a thickness of about 10 to 25 mm.

[0034] (D) Cooling process After process (C), the material is rapidly cooled, for example, to room temperature to about 200°C, by water cooling or the like. After cooling, the oxide film on the surface may be removed by mechanical polishing or the like if necessary. Furthermore, cold rolling (first cold rolling) may be performed as appropriate, according to the final plate thickness and subsequent cold working rate.

[0035] (E) Annealing process After process (D), the material is annealed. Annealing can cause, for example, the precipitation of Ni-Fe-P compounds, which can improve the hardness and conductivity of the copper alloy. If the heating temperature for annealing is low or the holding time is short, the conductivity will decrease. On the other hand, if the heating temperature for annealing is high or the holding time is long, the hardness will decrease. Annealing can usually be performed at a heating temperature of 300 to 500°C and a holding time of 30 minutes to 24 hours. When determining the annealing conditions on a production line, it is advisable to prepare test specimens by varying the heating temperature (heating zone temperature) and / or holding time (passing time) in advance and evaluate their hardness and conductivity. When manufacturing the product, it is advisable to select a heating temperature and holding time that results in sufficiently high conductivity of the test specimen, while keeping the heating temperature lower than the temperature at which the hardness of the test specimen significantly decreases, and / or keeping the holding time shorter than the time at which the hardness of the test specimen significantly decreases. The annealing conditions selected in this manner are considered to be within the range of heating temperature: 300-500°C and holding time: 30 minutes to 24 hours. After annealing, the oxide film on the surface may be removed by pickling or other methods as needed.

[0036] (F) Cold rolling process After process (E), cold rolling (hereinafter also referred to as "second cold rolling") is performed. The second cold rolling can increase the hardness of the copper alloy sheet by adding processing strain. The higher the cold working ratio of the second cold rolling, the higher the Vickers hardness may be, and it should be set appropriately so that the Vickers hardness is 250 HV or higher. According to one embodiment of the present invention, the cold working ratio of the second cold rolling is preferably 55% or more, more preferably 65% ​​or more, even more preferably 75% or more, and even more preferably 90% or more. There is no particular upper limit to the cold working ratio of the second cold rolling, and it should be set appropriately considering the constraints of the manufacturing equipment and / or productivity. The cold working ratio is calculated by the following formula (1). (T0-T1) / T0×100(%)···(1) In equation (1), T0 is the thickness of the sheet before cold rolling (mm), and T1 is the thickness of the sheet after cold rolling (mm).

[0037] (G) Stress relief annealing process After step (F), stress relief annealing may be performed as needed. Stress relief annealing can improve the half-etchability of the copper alloy sheet. In stress relief annealing, the heating temperature can be 300 to 500°C, and the holding time can be set appropriately according to the desired performance.

[0038] Although an example of a method for manufacturing a copper alloy sheet according to an embodiment of the present invention has been described, other steps may be included as long as they do not depart from the purpose of this disclosure. Furthermore, a person skilled in the art who understands the desired properties of the copper alloy sheet according to an embodiment of the present invention may, through trial and error, discover a method for manufacturing a copper alloy sheet having the desired properties according to an embodiment of the present invention, other than the manufacturing method described above. [Examples]

[0039] The embodiments of the present invention will be described in more detail below with reference to examples. The embodiments of the present invention are not limited by the following examples, and can be implemented with appropriate modifications within the scope that is consistent with the spirit described above and below, and all such modifications are included within the technical scope of the embodiments of the present invention. [Examples]

[0040] A copper alloy of a predetermined composition was melted in a kryptol furnace in air under charcoal covering at over 1100°C and cast to obtain a copper alloy ingot. The copper alloy ingot was subjected to soaking treatment at a heating temperature of 930°C for approximately 2 hours, and then hot-rolled to obtain a copper alloy sheet with a thickness of 15 mm. After hot-rolling, it was quickly water-cooled to room temperature to 200°C. After water-cooling, the surface oxide film was removed by mechanical polishing, and then the first cold-rolling was performed, varying the sheet thickness from 0.44 to 2.0 mm to change the processing rate for the subsequent second cold-rolling. Subsequently, annealing was performed at a heating temperature of 370 to 420°C for 17 hours. After annealing, the surface oxide was removed by pickling, and then the second cold-rolling was performed to obtain copper alloy sheets No. 1 to 25 with a sheet thickness of approximately 0.15 mm. For copper alloy sheets No. 1 to 25, the following measurement methods were used to determine the component composition (mass%), the cold working rate (%) of the second cold rolling process, the electrical conductivity (%IACS), and the Vickers hardness (HV).

[0041] <Component composition> Samples were taken from copper alloy ingots after casting by surface machining, and the concentration (mass %) of each element was determined to two decimal places using the ICP-AES method.

[0042] <Cold working rate in the second cold rolling process> For the copper alloy sheets before and after the second cold rolling, T0 (sheet thickness before the second cold rolling) and T1 (sheet thickness after the second cold rolling) were determined using a micrometer, and the cold working rate of the second cold rolling was calculated using the above formula (1).

[0043] <Conductivity> The resistivity of the second cold-rolled copper alloy sheet was measured using a double-bridge resistance measuring device. The conductivity (%IACS) was then calculated by dividing this resistivity by the resistivity of standard copper at 20°C, and rounded to the first decimal place to obtain an integer value.

[0044] <Vickers hardness> The Vickers hardness of the second batch of cold-rolled copper alloy sheets was measured using a micro-Vickers hardness tester with a load of 1 kg. Three measurements were taken for each copper alloy sheet, and the average value, rounded to the first decimal place, was adopted as the Vickers hardness of each copper alloy sheet. The results are shown in Table 1.

[0045] [Table 1]

[0046] Based on the results in Table 1, the following conclusions can be drawn. Numbers 15 and 18-25 in Table 1 all satisfy the requirements specified in the embodiments of the present invention, possessing sufficient hardness of 250 HV or higher and sufficient conductivity of 25% IACS or higher. On the other hand, Nos. 1-14 and 16-17 did not meet the requirements specified in the embodiments of the present invention and did not have sufficient hardness.

[0047] Copper alloy plates No. 1 to 10 had a Sn content of less than 1.0 mass% and a Vickers hardness of less than 250 HV.

[0048] Copper alloy sheets No. 11 to 14 have a Sn content of 1.02 mass%, which is near the lower limit of the Sn content range defined in the embodiments of the present invention. In this case, the cold working rate of the second cold rolling needs to be very high (for example, 90% or more), as in No. 15, but the cold working rate for Nos. 11 to 14 is less than 90%, resulting in a Vickers hardness of less than 250 HV.

[0049] Copper alloy sheets No. 16-17 have a Sn content of 1.52 mass%, which is near the middle of the Sn content range defined in the embodiments of the present invention. In this case, the cold working rate of the second cold rolling needs to be somewhat high (for example, 75% or more), as in No. 18-20, but the cold working rate for No. 16-17 is less than 75%, resulting in a Vickers hardness of less than 250 HV. Furthermore, when the Sn content was as high as 2.01% by mass, the Vickers hardness reached 250 HV or higher even with a cold working rate of less than 75%, as seen in samples No. 21-22. [Examples]

[0050] A copper alloy of a predetermined composition was melted in an atmospheric melting furnace at 1100°C or higher and cast to obtain a copper alloy ingot. The copper alloy ingot was subjected to a soaking treatment at a heating temperature of 900°C or higher and a holding time of 2 hours or higher, and then hot-rolled to obtain a copper alloy sheet with a thickness of 18 mm. After hot-rolling, it was quickly water-cooled to room temperature to 200°C. After water-cooling, the oxide film on the surface was mechanically removed, and then the first cold-rolling was performed. Subsequently, test specimens were prepared in advance on an annealing line by varying the heating temperature (heating zone temperature) and holding time (sheet passing time), and their hardness and conductivity were evaluated. Annealing was performed using the conditions that prevented a significant decrease in the hardness of the test specimens and resulted in sufficiently high conductivity, which were then defined as the annealing conditions for this embodiment. After annealing, surface oxides were removed by pickling, and then a second cold rolling was performed to achieve a cold working rate of 75% or more, yielding copper alloy sheets of No. 26-30 with a thickness of approximately 0.15 mm. A portion of the obtained samples was subjected to stress relief annealing by varying the heating zone temperature and sheet feeding conditions of the continuous annealing line (a total of 4 patterns). In Table 2 described later, condition A is for when stress relief annealing was not performed, and the conditions for when stress relief annealing was performed are labeled B, C, D, and E in order of increasing temperature. In this embodiment, stress relief annealing was performed under conditions that simulated a product heating temperature of 300-500°C, based on the structure of the continuous annealing line and heating device, heating, and sheet feeding speed.

[0051] For comparison, a commercially available product (manufactured by Kobe Steel, Ltd., CAC75-H 0.15mm, representative component composition: Ni: 2.5 mass%, Si: 0.55 mass%, Zn: 1.0 mass%, Sn: 0.2 mass%, and the remainder: copper and unavoidable impurities) was designated as copper alloy plate No. 31, and another commercially available product (CDA: C70250, Cu-Ni-Si copper alloy) was designated as copper alloy plate No. 32.

[0052] For copper alloy plates No. 26-30, the component composition (mass%) was determined in the same manner as in Example 1. For copper alloy plates No. 26 to 31, the electrical conductivity (%IACS) and Vickers hardness (HV) were determined in the same manner as in Example 1. In addition, the Young's modulus (GPa), 0.2% yield strength (MPa), and etching warpage height (mm) were determined using the following method. For copper alloy plates No. 27 and 32, the elements showing the highest peak height in SEM-EDX analysis after etching were investigated using the following method.

[0053] <Young's modulus and 0.2% proof stress> For each copper alloy sheet, test specimens were cut with the longitudinal direction perpendicular to both the rolling direction and the thickness direction, yielding three JIS No. 5 test specimens as described in JIS Z 2241. The length (mm) in the rolling direction and thickness (mm) of the test specimens were measured using a 1 / 1000 micrometer to obtain the cross-sectional area. Next, tensile tests were performed on the test specimens using a 100kN autograph and an automatic extensometer manufactured by Shimadzu Corporation, and data on nominal strain (%) and nominal stress (MPa) were obtained. From the obtained data, the Young's modulus (GPa) was obtained by linear approximation in the elastic deformation range of nominal stress 100 to 300 (MPa). The Young's modulus in the perpendicular direction was measured for three test specimens, and the average value, rounded to the first decimal place, was adopted as the Young's modulus in the perpendicular direction for each copper alloy plate. Furthermore, the obtained nominal strain (%) and nominal stress (MPa) were graphed, and a straight line was drawn parallel to the above Young's modulus (GPa) and passing through nominal stress 0 MPa and nominal strain 0.2%. The stress value at the intersection of the graph and the curve was read as the 0.2% yield strength (MPa). The 0.2% yield strength in the perpendicular direction was determined for three test specimens, and the average value, rounded to the first decimal place, was adopted as the 0.2% yield strength in the perpendicular direction for each copper alloy plate.

[0054] <Maximum height of warping after etching> For each copper alloy sheet, three test pieces were cut from the center perpendicular to the sheet using wire electrical discharge machining, with lengths of 60 mm in the rolling direction and 6 mm in the perpendicular direction. The maximum warp height (mm) was determined when etching was performed on one surface perpendicular to the thickness direction of the three obtained test pieces, by repeating steps (a) to (e) below, until the sheet thickness was reduced to 60%. The maximum warp height (mm) of the three test pieces was compared, and the value obtained by rounding the maximum value (mm) to the third decimal place was adopted as the maximum warp height after etching for each copper alloy sheet. (a) Thickness measurement: Five measurements were taken along the longitudinal direction (rolling direction) using a micrometer, and the average value (μm) was taken as the thickness of each test specimen. (b) Measurement of warpage height: The test specimen was placed on a flat surface (on a jig 40 mm in length) with the etched surface facing downwards (the convex surface facing upwards). Then, the maximum height (mm) of the test specimen from the flat surface was measured using a magnifying glass as the warpage height. (c) Masking: After measuring the warp height, the back surface (convex surface) opposite the etching surface was masked with a fluorocarbon mask. (d) Etching: Etching was performed using a solution of 1050 ml of nitric acid and 750 ml of water, which were stirred together. (e) Masking removal: The fluorocarbon mask was removed by immersion in acetone and ultrasonic cleaning.

[0055] <Elements showing the highest peak height in SEM-EDX analysis after etching> Each copper alloy plate specimen was etched by immersion for 130 seconds in a general-purpose copper etching solution (Mitsubishi Gas Chemical Co., Ltd., Clean Etch CPB50, components: sulfuric acid: 24% by mass, hydrogen peroxide: less than 5% by mass, ethylene glycol: less than 3% by mass, and water) maintained at 40-50°C. After etching, the specimens were washed by immersion in water in a beaker and dried. The etched surface was then measured at a depth of 150-300 μm. 2 For the area of ​​the sample, we determined the element that exhibited the highest peak height among all elements when SEM-EDX analysis was performed under the condition of an accelerating voltage of 15kV. The results are shown in Table 2.

[0056] [Table 2]

[0057] Based on the results in Table 2, the following conclusions can be drawn. Copper alloy plates No. 26 to 30 in Table 2 all satisfied the requirements specified in the embodiments of the present invention, possessing sufficient hardness of 250 HV or higher and sufficient conductivity of 25% IACS or higher. They also exhibited desirable properties, such as a Young's modulus in the perpendicular direction of 140 GPa or higher and a 0.2% yield strength in the perpendicular direction of 890 MPa or higher. Copper alloy plate No. 27 showed a desirable physical property, in which copper was the element exhibiting the highest peak height in SEM-EDX analysis after etching. Furthermore, copper alloy plates No. 27 to 30 are examples of stress-relieving annealing performed under preferred conditions as defined in the embodiments of the present invention, and they showed favorable performance in that the maximum height of warping after etching was 7.0 times or less the plate thickness before etching.

[0058] On the other hand, copper alloy plate No. 26 had not undergone stress-relieving annealing, and its warp height after etching was more than 7.0 times its thickness before etching (0.15 mm). Copper alloy sheet No. 31 had a Young's modulus in the perpendicular direction of less than 140 GPa and a 0.2% yield strength of less than 890 MPa. This is thought to be because copper alloy sheet No. 31 did not meet the necessary manufacturing conditions, such as the component composition, annealing conditions, and cold working rate of the second cold rolling, as specified in the embodiment of the present invention. In SEM-EDX analysis after etching, copper alloy plate No. 32 showed that the element with the highest peak height was Ni. This is thought to be because copper alloy plate No. 32 does not meet the requirements (particularly the component composition) specified in the embodiment of the present invention.

Claims

1. The component composition is, Ni: 0.6 to 1.0% by mass, Fe: 0.05 to 0.20% by mass, P: 0.06 to 0.15% by mass, Sn: 1.0–2.2% by mass, and The remainder consists of copper and unavoidable impurities. The Vickers hardness is 250 HV or higher. A copper alloy plate with an electrical conductivity of 25% IACS or higher.

2. The copper alloy plate according to claim 1, further comprising Zn: 0.05 to 0.20 mass%.

3. The copper alloy sheet according to claim 1 or 2, wherein the Young's modulus in the direction perpendicular to both the rolling direction and the thickness direction is 140 GPa or more.

4. The copper alloy sheet according to claim 1 or 2, wherein the 0.2% yield strength in the direction perpendicular to both the rolling direction and the thickness direction is 890 MPa or more.

5. A copper alloy plate according to claim 1 or 2, wherein a plate material having a length of 60 mm in the rolling direction and a length of 6 mm in the direction perpendicular to both the rolling direction and the thickness direction is cut out, and one surface of the plate material perpendicular to the thickness direction is etched until the thickness is reduced to 60%, and the maximum height of the warp when etched is 7.0 times or less the thickness of the plate before etching.

6. A copper alloy plate according to claim 1 or 2, wherein when the surface is etched for 130 seconds by immersion in a copper etching solution containing sulfuric acid: 24% by mass, hydrogen peroxide: less than 5% by mass, ethylene glycol: less than 3% by mass, and water at a temperature of 40 to 50°C, washed by immersion in water, and dried, the peak height of the copper element is the largest among all elements when the surface is analyzed by SEM-EDX at an accelerating voltage of 15 kV.

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