WO2016171055A1

WO2016171055A1 - Copper alloy material and method for producing same

Info

Publication number: WO2016171055A1
Application number: PCT/JP2016/061908
Authority: WO
Inventors: 恵人藤井; 岳己磯松; 樋口　優
Original assignee: 古河電気工業株式会社
Priority date: 2015-04-24
Filing date: 2016-04-13
Publication date: 2016-10-27
Also published as: KR20170125805A; JP6155405B2; JPWO2016171055A1; CN107208191A; KR102059917B1; CN107208191B; TWI695075B; TW201704490A

Abstract

The present invention provides: a copper alloy material which exhibits good heat resistance in addition to high strength, high electrical conductivity and good bending workability; and a method for producing same. This copper alloy material is characterized by having an alloy composition that contains 0.05-1.2 mass % of Ni, 0.01-0.15 mass % of P and 0.05-2.5 mass % of Sn, with the remainder comprising Cu and unavoidable impurities, and is characterized in that when a surface of the material is observed using an FE-SEM after electrolytic polishing, the number of compound particles having particle diameters of 5-30 nm is 20 particles/μm² or more and the number of compound particles having particle diameters of greater than 30 nm is 1 particle/μm² or less in a field of view having an area measuring 1μm × 1μm.

Description

Copper alloy material and method for producing the same

The present invention relates to a copper alloy material and a method for manufacturing the same, and more particularly to a copper alloy material used for electrical and electronic parts such as lead frames used in semiconductor devices and a method for manufacturing the same.

A lead frame used in a semiconductor device such as an IC or LSI is formed by pressing a copper alloy material. At this time, processing strain remains in the material. If this processing strain remains, the material is warped during the subsequent etching process, and the dimensional accuracy of the lead pin interval of the lead frame decreases. For this reason, the lead frame after press working is usually subjected to heat treatment at 400 to 450 ° C. to remove the processing strain. During this heat treatment, the crystal structure of the copper alloy is recrystallized, so that the copper alloy material It is known that the strength of the steel tends to decrease. Therefore, the copper alloy material for electronic equipment used for the lead frame is required to have a characteristic (heat resistance) that does not decrease the strength even when the heat treatment is performed.

In addition to having high strength for application to miniaturized parts and high conductivity for suppressing heat generation of parts, the copper alloy material for lead frames has a high degree of freedom in molding parts. It is also required to have good bending workability to enhance.

Cu-Ni-Sn-P-based alloys are widely provided as copper alloy materials that satisfy these requirements. The Cu—Ni—Sn—P based alloy can have both high strength, high electrical conductivity, and good bending workability by precipitating a Ni—P based compound.

In Patent Documents 1 to 9, by controlling the size and distribution of precipitates, in addition to tensile strength, electrical conductivity and bending workability, spring properties, stress relaxation properties, press workability, corrosion resistance, plating properties, solder wetting It has been studied to combine various properties such as heat resistance, migration resistance, and hot workability.

Japanese Patent Laid-Open No. 4-154944 JP-A-4-236636 JP-A-10-226835 JP 2000-129377 A JP 2000-256814 A JP 2001-262255 A JP 2001-262297 A JP 2006-291356 A JP 2007-100111 A

Cu—Ni—Sn—P alloy is an excellent alloy system that has high strength, high electrical conductivity, and good bending workability, but is heat treated at 400 to 450 ° C. applied to the lead frame after press working. It is hard to say that the heat resistance against is sufficient.

In each of Patent Documents 1 to 9, although attempts have been made to improve various material properties, they do not focus on improving heat resistance.

In view of the above circumstances, an object of the present invention is to provide a copper alloy material having a good heat resistance in addition to a high strength, a high conductivity, and a good bending workability, and a method for producing the same.

The present inventors have studied Cu—Ni—Sn—P based alloys used for electric and electronic parts such as lead frames, and 0.05 to 1.2 mass% of Ni and 0.01 to 0.01% of P. It has an alloy composition containing 0.15% by mass and 0.05 to 2.5% by mass of Sn, and the surface of the material after electropolishing is observed with an FE-SEM. By setting the number ratio of the compound particles having a particle diameter of 5 to 30 nm to 20 particles / μm ² or more and the number ratio of the compound particles having a particle diameter exceeding 30 nm to 1 particle / μm ² or less, high strength, high conductivity, and good The present inventors have found that a copper alloy material having not only excellent bending workability but also excellent heat resistance can be obtained, and the present invention has been completed.

That is, the gist configuration of the present invention is as follows.
(1) An alloy containing 0.05 to 1.2% by mass of Ni, 0.01 to 0.15% by mass of P and 0.05 to 2.5% by mass of Sn, with the balance being Cu and inevitable impurities The surface of the material after electropolishing having a composition is observed by FE-SEM, and the ratio of the number of compound particles having a particle size of 5 to 30 nm per 1 μm × 1 μm viewing area is 20 particles / μm ² or more. A copper alloy material, wherein the number ratio of the compound particles having a particle size exceeding 30 nm is 1 / μm ² or less.

(2) 0.05 to 1.2% by mass of Ni, 0.01 to 0.15% by mass of P and 0.05 to 2.5% by mass of Sn, and further Fe, Zn, Pb, Si , Mg, Zr, Cr, Ti, Mn, and Co, Fe is 0.001 to 0.1% by mass, Zn is 0.001 to 0.5% by mass, and Pb is 0.001 to 0.05 mass%, Si is 0.001 to 0.1 mass%, Mg is 0.001 to 0.3 mass%, Zr is 0.001 to 0.15 mass%, and Cr is 0.00. 001 to 0.3% by mass, Ti is 0.001 to 0.05% by mass, Mn is 0.001 to 0.2% by mass, Co is 0.001 to 0.2% by mass, and Mg, Zr , Cr, Ti, Mn and Co when the total content is 0.001 to 0.5 mass%, the balance An alloy composition composed of Cu and inevitable impurities, the surface of the material after electropolishing is observed with FE-SEM, and the number ratio of the compound particles having a particle diameter of 5 to 30 nm per 1 μm × 1 μm viewing area is 20 / [mu] m ² or more, the copper alloy material, wherein the ratio of the number of compound particles is a particle diameter of more than 30nm is one / [mu] m ² or less.

(3) The copper alloy as described in (1) or (2) above, containing 0.05 to 0.5% by mass of Sn, having a tensile strength of 400 MPa or more and a conductivity of 50% IACS or more. material.

(4) The content of Sn is more than 0.5% by mass and 2.5% by mass or less, the tensile strength is 500 MPa or more, and the conductivity is 25% IACS or more. Copper alloy material.

(5) The method for producing a copper alloy material as described in any one of (1) to (4) above, which comprises the following steps (a) to (e):
(A) A melt casting step in which the cooling rate to 300 ° C. is 30 ° C./min or more.
(B) A homogenization heat treatment step in which the temperature is raised at 5 ° C./min or more and maintained at 600 to 1000 ° C. for 30 minutes to 10 hours.
(C) A hot rolling step in which the cooling rate to 300 ° C. is 30 ° C./min or more.
(D) A cold rolling step in which the processing rate is 80% or more.
(E) An annealing step of holding at 350 to 600 ° C. for 5 seconds to 10 hours.

According to the present invention, 0.05 to 1.2% by mass of Ni, 0.01 to 0.15% by mass of P and 0.05 to 2.5% by mass of Sn, with the balance being Cu and inevitable impurities The surface of the material after electrolytic polishing is observed with an FE-SEM, and the ratio of the number of compound particles having a particle diameter of 5 to 30 nm per field area of 1 μm × 1 μm is 20 particles / μm ² or more. In addition to high strength, high electrical conductivity, and good bending workability, copper having better heat resistance can be obtained by setting the number ratio of compound particles having a particle diameter of more than 30 nm to 1 / μm ² or less. It is now possible to provide alloy materials.

FIG. 1 is an SEM photograph of the surface after electrolytic polishing of a copper alloy material of the present invention (Example 14) observed with an FE-SEM at a magnification of 50000 times. FIG. 2 is an SEM photograph of the surface after electropolishing of Comparative Example 22 observed with an FE-SEM at a magnification of 50000 times.

Hereinafter, preferred embodiments of the copper alloy material of the present invention will be described in detail.
(Component composition of copper alloy material)
The basic composition of the copper alloy material of the present invention contains 0.05 to 1.2% by mass of Ni, 0.01 to 0.15% by mass of P and 0.05 to 2.5% by mass of Sn, and the balance Are Cu and inevitable impurities.

[Essential ingredients]
(Ni: 0.05 to 1.2% by mass)
Ni is an element that increases the strength by forming a solid solution with the matrix and forming a compound with P. Ni has the effect of increasing the electrical conductivity and heat resistance by generating a compound with P and precipitating this product. However, if the Ni content is less than 0.05% by mass, the effect cannot be sufficiently exerted, and if it exceeds 1.2% by mass, the conductivity is significantly reduced. Therefore, the Ni content is 0.05 to 1.2% by mass, preferably 0.10 to 1.00% by mass, and more preferably 0.10 to 0.40% by mass.

(P: 0.01 to 0.15% by mass)
P is an element that contributes to an increase in strength, an increase in conductivity, and an improvement in heat resistance by forming a compound with Ni. However, if the P content is less than 0.01% by mass, the effect cannot be sufficiently obtained, and if it exceeds 0.15% by mass, the conductivity is lowered and coarse (for example, the particle diameter exceeds 30 nm). It causes a decrease in bending workability due to the formation of compound particles, a decrease in heat resistance and a decrease in workability due to a decrease in the production ratio of fine compounds (for example, particle diameter of 5 to 30 nm). Therefore, the P content is set to 0.01 to 0.15% by mass, preferably 0.01 to 0.10% by mass, and more preferably 0.05 to 0.10% by mass.

(Sn: 0.05 to 2.5% by mass)
Sn is an element that contributes to an increase in strength and an improvement in heat resistance by dissolving in the matrix. However, if the Sn content is less than 0.05% by mass, the effect cannot be sufficiently obtained, and if it exceeds 2.5% by mass, the electrical conductivity is lowered and the hot workability is deteriorated. Therefore, the Sn content is set to 0.05 to 2.5% by mass. Of the tensile strength and electrical conductivity, when emphasizing electrical conductivity in particular, if the Sn content is limited to 0.05 to 0.5% by mass, the tensile strength is 400 MPa or more and 50% IACS or more. It is preferable in that it can have a high electrical conductivity, and in particular, when the tensile strength is important, if the Sn content is limited to 0.5% by mass or more and 2.5% by mass or less, 25% IACS or more This is preferable in that it can have a high tensile strength of 500 MPa or more.

[Optional components]
In the present invention, it is essential to contain the above-described Ni, P and Sn as a basic composition, but as optional additional components, Fe, Zn, Pb, Si, Mg, Zr, Cr, Ti, Mn and Co At least one component selected from among them may be selectively contained.

(Fe: 0.001 to 0.1% by mass)
Fe is an element that contributes to an increase in strength and an improvement in heat resistance by forming a compound with P. In order to achieve this effect, the Fe content is preferably 0.001% by mass or more. However, if the Fe content is more than 0.1% by mass, the material tends to be magnetized, and if the material is magnetized, the transmission characteristics of the transmission signal in the lead frame may be deteriorated. Therefore, the Fe content is preferably 0.001 to 0.1% by mass, more preferably 0.001 to 0.05% by mass, and further preferably 0.001 to 0.01% by mass.

(Zn: 0.001 to 0.5 mass%)
Zn is an element that contributes to an increase in strength, improvement in solder wettability, and improvement in plating properties by dissolving in the matrix phase. To achieve this effect, the Zn content is 0.001% by mass or more. It is preferable to do. However, when the Zn content is more than 0.5% by mass, the conductivity tends to decrease. Therefore, the Zn content is preferably 0.001 to 0.5% by mass, more preferably 0.01 to 0.5% by mass, and further preferably 0.1 to 0.5% by mass.

(Pb: 0.001 to 0.05 mass%)
Pb is an element that contributes to the improvement of press workability. In order to achieve this effect, the Pb content is preferably 0.001% by mass or more. However, even if the Pb content is more than 0.05% by mass, no further improvement in the effect is observed, and it is desirable to suppress the Pb content as much as possible from the viewpoint of environmental protection in recent years. For this reason, the Pb content is preferably 0.001 to 0.05% by mass, and more preferably 0.001 to 0.01% by mass.

(Si: 0.001 to 0.1% by mass)
Si is an element that contributes to an increase in strength. In order to achieve this effect, the Si content is preferably 0.001% by mass or more. However, when the Si content is more than 0.1% by mass, there is a concern that the electrical conductivity is lowered and the bending workability is deteriorated due to the generation of a coarse compound. Therefore, the Si content is preferably 0.001 to 0.1% by mass, and more preferably 0.01 to 0.1% by mass.

(Mg: 0.001 to 0.3% by mass)
Mg is an element that contributes to an increase in strength and an improvement in heat resistance. Further, for example, it contributes to improvement of stress relaxation resistance in a spring contact of an electronic component. In order to achieve these effects, the Mg content is preferably 0.001% by mass or more. However, when the Mg content is more than 0.3% by mass, there is a concern that the electrical conductivity is lowered and inclusions are formed during casting. For this reason, the Mg content is preferably 0.001 to 0.3% by mass, and more preferably 0.01 to 0.3% by mass.

(Zr: 0.001 to 0.15 mass%)
Zr is an element that contributes to an increase in strength and an improvement in heat resistance. Further, for example, it contributes to improvement of stress relaxation resistance in a spring contact of an electronic component. In order to achieve these effects, the Zr content is preferably 0.001% by mass or more. However, when the Zr content is more than 0.15% by mass, there is a concern about a decrease in conductivity and cracking during hot working. For this reason, the Zr content is preferably 0.001 to 0.15% by mass, and more preferably 0.01 to 0.1% by mass.

(Cr: 0.001 to 0.3% by mass)
Cr is an element that contributes to an increase in strength and an improvement in heat resistance. In order to achieve this effect, the Cr content is preferably 0.001% by mass or more. However, when the Cr content is more than 0.3% by mass, there is a concern that bending workability may be lowered due to generation of crystallized substances during casting. For this reason, the Cr content is preferably 0.001 to 0.3% by mass, and more preferably 0.01 to 0.3% by mass.

(Ti: 0.001 to 0.05 mass%)
Ti is an element that contributes to an increase in strength and an improvement in heat resistance. Further, for example, it contributes to improvement of stress relaxation resistance in a spring contact of an electronic component. In order to achieve these effects, the Ti content is preferably 0.001% by mass or more. However, if the Ti content is more than 0.05% by mass, there is a concern about a decrease in electrical conductivity or abnormal casting surface on the ingot surface. For this reason, the Ti content is preferably 0.001 to 0.05% by mass, and more preferably 0.01 to 0.05% by mass.

(Mn: 0.001 to 0.2% by mass)
Mn is an element that contributes to an increase in strength, heat resistance, and hot workability. To achieve this effect, the Mn content is preferably 0.001% by mass or more. However, when the Mn content is more than 0.2% by mass, there is a concern that the electrical conductivity is lowered. For this reason, the Mn content is preferably 0.001 to 0.2% by mass, and more preferably 0.01 to 0.2% by mass.

(Co: 0.001 to 0.2% by mass)
Co is an element that contributes to an increase in strength and an improvement in hot workability. In order to achieve this effect, the Co content is preferably 0.001% by mass or more. However, if the Co content is more than 0.2% by mass, there is a concern that the electrical conductivity will decrease. Therefore, the Co content is preferably 0.001 to 0.2% by mass, more preferably 0.01 to 0.2% by mass.

(Total content when containing two or more of Mg, Zr, Cr, Ti, Mn and Co: 0.001 to 0.5 mass%)
Mg, Zr, Cr, Ti, Mn and Co contribute to an increase in strength and an improvement in heat resistance by forming a compound with P. The addition amount of these elements is preferably 0.001 to 0.5% by mass, more preferably 0.01 to 0.5% by mass, and further preferably 0.1 to 0.5% by mass. When it is larger than 0.5% by mass, there is a concern about decrease in conductivity and decrease in bending workability due to the formation of a coarse compound.

(Compound particles)
In the present invention, the surface of the material after electropolishing is observed with an FE-SEM, and the ratio of the number of compound particles having a particle diameter of 5 to 30 nm per 1 μm × 1 μm viewing area is 20 particles / μm ² or more. By setting the number ratio of the compound particles having a particle size exceeding 30 nm to 1 / μm ² or less, a copper alloy material having good heat resistance in addition to high strength, high conductivity, and good bending workability is obtained. Obtainable. The term “compound particles” as used herein is a general term for inclusions and crystallization products formed during casting and precipitates formed after casting solidification. The particle diameter of the compound particles means the length of the major axis. When the number ratio of fine compound particles having a particle size of 5 to 30 nm per particle area of 1 μm × 1 μm is 20 / μm ² or more, a sufficient pinning effect can be obtained by the fine compound particles. Crystals are suppressed and good heat resistance is obtained. On the other hand, when the number ratio of fine compound particles is less than 20 / μm ^2, good heat resistance cannot be obtained. Moreover, favorable bending workability is obtained because the number ratio of the coarse compound particle | grains whose particle diameter exceeds 30 nm shall be 1 piece / micrometer < ² > or less. When the number ratio of the coarse compound particles exceeds 1 / μm ² , the coarse compound particles serve as a starting point of fracture, and the bending workability is remarkably deteriorated. Further, at this time, if a large number of coarse compound particles are formed, the number ratio of fine compound particles tends to decrease, so that heat resistance may be deteriorated. Conventionally, the dispersion state of compound particles is often observed with a transmission electron microscope (TEM) and is often expressed by the number and area ratio in the field of view, but these values depend on the thickness of the test piece. . However, it is difficult to make the thickness of the test pieces prepared for TEM uniform. In addition, even if the same test piece is used for measurement, there is a possibility that the results will be slightly different depending on the measurement time. Therefore, in the present invention, the number ratio of the compound particles was evaluated using a field emission scanning electron microscope (FE-SEM) that does not depend on the thickness of the test piece.

(Method for producing copper alloy material)
Next, the manufacturing method of the copper alloy material of this invention is demonstrated.
The copper alloy material of the present invention is usually produced by performing melt casting → homogenization heat treatment → hot rolling → cold rolling → annealing → finish rolling. Between each process, you may perform chamfering, buffing, pickling, degreasing, etc. suitably as needed. Moreover, cold rolling and annealing may be repeated a plurality of times, and low temperature annealing may be performed after finish rolling. In the production method of the present invention, it is important not to produce coarse compound particles as much as possible by melt casting, homogenization heat treatment and hot rolling, but to produce many fine precipitates by subsequent cold rolling and annealing. . Although the manufacturing method of the present invention has the same number of steps as the conventional method, the material characteristics can be improved by appropriately adjusting each process condition.

<Melting casting>
Melting casting may be carried out by a general method, but in the present invention, cooling to 300 ° C. at the time of casting is performed at a cooling rate of 30 ° C./min or more, so that crystallization and precipitation at the time of cooling are performed. It is preferable in that it suppresses the formation of coarse compound particles. This is because if the cooling rate is lower than 30 ° C./min, crystallization and precipitation during cooling cannot be sufficiently suppressed, and coarse compound particles tend to be generated.

<Homogenization heat treatment>
The homogenization heat treatment is carried out in order to make the coarse compound particles produced by the melt casting form a solid solution in the matrix phase to obtain a solution state. The homogenization heat treatment is preferably maintained at 600 to 1000 ° C. for 30 minutes to 10 hours. Conventionally, the heating rate of the homogenization heat treatment has not been regarded as important, but in the present invention, in order to obtain the specified material structure, the heating rate is particularly 5 ° C./min or more, preferably 10 ° C./min or more. It is necessary to control. If the rate of temperature increase is less than 5 ° C./min, coarse compound particles formed by dissolution casting grow at the time of temperature rise, and the coarse compound particles can be sufficiently dissolved in the parent phase by the subsequent homogenization heat treatment. This is because it is difficult to remain and the bending workability is deteriorated with the final characteristics. In addition, the number ratio of fine compound particles is reduced, so that the heat resistance is also deteriorated. When at least one of the holding temperature of less than 600 ° C. and the holding time of less than 30 minutes is satisfied, coarse compound particles that cannot be completely dissolved in the matrix phase are likely to remain, and the bending properties are deteriorated in the final characteristics. This is because, when the holding temperature exceeds 1000 ° C., hot working cracks may occur in the subsequent hot rolling process. The upper limit of the retention time is preferably 10 hours from the viewpoint of saturation of the effect of solution treatment and time constraints in actual production.

<Hot rolling>
Hot rolling is preferably performed at 550 to 950 ° C. In the present invention, in particular, the cooling rate up to 300 ° C. needs to be 30 ° C./min or more. This is because if the cooling rate to 300 ° C. is smaller than 30 ° C./min, coarse compound particles are likely to precipitate during cooling, which adversely affects the final characteristics.

<Cold rolling>
The cold rolling after hot rolling is preferably performed at a processing rate of 80% or more. When the processing rate is less than 80%, strain is not uniformly introduced into the material, and when fine compound particles are precipitated by subsequent annealing, there is a possibility that a difference in the precipitation state occurs in the material.

<Annealing>
The annealing is preferably held at 350 to 600 ° C. for 5 seconds to 10 hours. If the temperature is lower than the above range for a short time, the precipitation of fine compound particles is insufficient, and there is a concern that the strength and conductivity are lowered. If the temperature is higher than the above range for a long time, coarse compound particles are produced. This is because there is a concern about precipitation and deterioration of bending workability and heat resistance.

<Finish rolling>
The processing rate of finish rolling is not particularly limited, but is preferably 60% or less in order to obtain good bending workability.

<Low temperature annealing>
After the finish rolling, low temperature annealing may be performed at 250 to 400 ° C. for 2 seconds to 5 hours. By low temperature annealing, the spring property and stress relaxation resistance of the material can be improved. If the temperature is lower than the above range for a short time, the effect of low temperature annealing may not be obtained, and if the temperature is higher than the above range for a long time, fine compound particles grow coarsely, This is because the heat resistance may be adversely affected. In addition, recrystallization of the material may proceed, and a desired strength may not be obtained.

The copper alloy material of the present invention has high strength, high electrical conductivity, and good bending workability by controlling the size and amount of compound particles in a Cu—Ni—Sn—P based copper alloy having a predetermined alloy composition. In addition, it can also have heat resistance. For this reason, the copper alloy material of the present invention is suitable for use in electrical and electronic parts such as lead frames.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

(Examples 1 to 26 and Comparative Examples 1 to 22)
Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

After melting the alloy components and casting to 300 ° C. while cooling at a cooling rate of 30 ° C./min or more to produce an ingot having the component composition shown in Table 1, the temperature is increased at the temperature rising rate shown in Table 2. Then, a homogenization heat treatment was performed at 600 to 1000 ° C. for 30 minutes to 10 hours, and then hot rolling was performed. After hot rolling, it was cooled at a cooling rate up to 300 ° C. shown in Table 2, and then the surface oxide layer was removed by face milling, and cold rolling was performed at a processing rate of 80% or more. Thereafter, annealing is performed at 350 to 600 ° C. for 5 seconds to 10 hours, then finish rolling is performed at a processing rate of 60% or less, and finally low temperature annealing is performed at 250 to 400 ° C. for 2 seconds to 5 hours, A copper alloy material having a thickness of 0.5 mm was produced.

The following evaluation was performed on the specimens thus manufactured.

(Tissue observation)
After 20 μm of the surface of a test piece (size: 20 mm × 20 mm) collected from each manufactured copper alloy material (test material) is electropolished with a phosphoric acid aqueous solution, the surface of the material is 10000-100000 times by FE-SEM. Observed. The observation is performed by observing three fields of view of 1 μm × 1 μm arbitrarily, and the number of fine compound particles having a particle diameter of 5 to 30 nm and the number of coarse compound particles having a particle diameter exceeding 30 nm within the field of view. Was measured. Thereafter, the measured number was converted into a number ratio per visual field area of 1 μm × 1 μm (1 μm ² ). The converted number ratio was rounded off, and the fine compound particles were shown as integers, and the coarse compound particles were shown up to the second decimal place.

(Measurement of tensile strength)
Tensile strength was specified in JIS Z2241: 2011 by extracting three specimens of No. 5 specified in Annex B of JIS Z2241: 2011 along the rolling parallel direction. Three samples were measured according to “Metal material tensile test method”. Table 2 shows the average values of the tensile strengths.

(Measurement of conductivity)
In a constant temperature bath maintained at 20 ° C. (± 0.5 ° C.), the specific resistance value was measured by the four probe method, and the conductivity was calculated from the measured specific resistance value. In addition, the distance between terminals was 100 mm.

(Bending workability)
A bending test was performed based on JCBA T307: 2007. A test piece having a plate width of 10 mm was bent with an inner bending radius of 0.5 mm with respect to a direction (GW direction) and a direction (BW direction) in which the bending axis was perpendicular to the rolling direction. W-bending was performed at an angle of 90 °. For electrical and electronic parts such as lead frames, G. W. Direction and B. W. Since the bending process in both directions is assumed, the surface of the apex of the bent part after bending is observed with an optical microscope. W. Direction and B. W. Those in which no crack occurred in any of the directions were evaluated as good bending workability (A) and those in which cracking occurred were evaluated as poor bending workability (D). The evaluation results are shown in Table 2.

(Heat-resistant)
The heat resistance is a value obtained by putting a test piece in a salt bath heated to 450 ° C., performing a heat treatment of taking out after 5 minutes and cooling with water and dividing the hardness after the heat treatment by the hardness before the heat treatment. The case of 8 or more was evaluated as good heat resistance (A), and the case of less than 0.8 was evaluated as heat resistance defect (D). The evaluation results are shown in Table 2. The hardness was measured based on the Vickers hardness test-test method specified in JIS Z 2244: 2009. Moreover, since the film after the heat treatment had a film formed on the surface in contact with the salt bath, the hardness was measured after removing it by pickling.

From the results shown in Table 1 and Table 2, in Examples 1 to 13 where the Sn concentration is in the range of 0.05 to 0.5 mass%, the tensile strength is 432 to 492 MPa, which is 400 MPa or more, and the conductivity is 50 to 77% IACS and 50% IACS or more, and good bending workability (A) and good heat resistance (A) are obtained. On the other hand, Comparative Examples 1 to 9 in which the component composition shown in Table 1 is outside the scope of the present invention and Comparative Examples 10 and 11 in which the production conditions shown in Table 2 are outside the scope of the present invention, At least one of tensile strength, electrical conductivity, bending workability, heat resistance and manufacturability was inferior.

In Examples 14 to 26 in which the Sn concentration is in the range of 0.5% by mass to 2.5% by mass or less, the tensile strength is 512 to 593 MPa and 500 MPa or more, and the conductivity is 27 to 38% IACS. 25% IACS or more, and good bending workability (A) and good heat resistance (A) are obtained. On the other hand, Comparative Examples 12 to 20 in which the component composition shown in Table 1 is outside the scope of the present invention and Comparative Examples 21 and 22 in which the production conditions shown in Table 2 are outside the scope of the present invention, At least one of tensile strength, electrical conductivity, bending workability, heat resistance and manufacturability was inferior.

1 and 2 show SEM photographs when the surfaces of the copper alloy materials of Example 14 and Comparative Example 22 after electropolishing were observed by FE-SEM, respectively. In the copper alloy material of Example 14 shown in FIG. 1, fine compound particles are dispersed, whereas in the copper alloy material of Comparative Example 22 shown in FIG. 2, the compound particles are coarse. .

According to the present invention, it has become possible to provide a copper alloy material having not only high strength, high conductivity, and good bending workability, but also good heat resistance. The copper alloy material of the present invention is particularly suitable for use in electrical and electronic parts such as lead frames used in semiconductor devices.

Claims

It has an alloy composition containing 0.05 to 1.2 mass% of Ni, 0.01 to 0.15 mass% of P and 0.05 to 2.5 mass% of Sn, with the balance being Cu and inevitable impurities. The surface of the material after electropolishing is observed with an FE-SEM, and the number ratio of compound particles having a particle diameter of 5 to 30 nm per particle area of 1 μm × 1 μm is 20 particles / μm 2 or more, and the particle diameter exceeds 30 nm. A copper alloy material, wherein the number ratio of the compound particles is 1 / μm 2 or less.
0.05 to 1.2% by mass of Ni, 0.01 to 0.15% by mass of P and 0.05 to 2.5% by mass of Sn, and Fe, Zn, Pb, Si, Mg, It contains at least one component selected from Zr, Cr, Ti, Mn and Co, Fe is 0.001 to 0.1% by mass, Zn is 0.001 to 0.5% by mass, and Pb is 0.001. ~ 0.05 mass%, Si 0.001 to 0.1 mass%, Mg 0.001 to 0.3 mass%, Zr 0.001 to 0.15 mass%, Cr 0.001 to 0 0.3 mass%, Ti 0.001-0.05 mass%, Mn 0.001-0.2 mass% and Co 0.001-0.2 mass%, and Mg, Zr, Cr, When 2 or more of Ti, Mn and Co are contained, the total content is 0.001 to 0.5% by mass, and the balance is Cu The surface of the material after electropolishing is observed with an FE-SEM, and the ratio of the number of compound particles having a particle diameter of 5 to 30 nm per field area of 1 μm × 1 μm is 20 / A copper alloy material characterized in that the number ratio of compound particles having a particle diameter of not less than μm 2 and exceeding 30 nm is 1 / μm 2 or less.
3. The copper alloy material according to claim 1, comprising 0.05 to 0.5 mass% of Sn, having a tensile strength of 400 MPa or more and an electrical conductivity of 50% IACS or more.
The copper alloy material according to claim 1 or 2, wherein Sn is contained in an amount exceeding 0.5 mass% and not more than 2.5 mass%, a tensile strength is 500 MPa or more, and an electrical conductivity is 25% IACS or more.
The method for producing a copper alloy material according to any one of claims 1 to 4, comprising the following steps (a) to (e):
(A) A melt casting step in which the cooling rate to 300 ° C. is 30 ° C./min or more.
(B) A homogenization heat treatment step in which the temperature is raised at 5 ° C./min or more and maintained at 600 to 1000 ° C. for 30 minutes to 10 hours.
(C) A hot rolling step in which the cooling rate to 300 ° C. is 30 ° C./min or more.
(D) A cold rolling step in which the processing rate is 80% or more.
(E) An annealing step of holding at 350 to 600 ° C. for 5 seconds to 10 hours.