KR102059917B1 - Copper alloy material and method for producing same - Google Patents

Abstract

The present invention provides a copper alloy material having not only high strength, high electrical conductivity and good bending workability but also good heat resistance, and a method of manufacturing the same.
The copper alloy material of this invention contains 0.05-1.2 mass% of Ni, 0.01-0.15 mass% of P, and 0.05-2.5 mass% of Sn, and has the alloy composition which remainder consists of Cu and an unavoidable impurity, The material after electropolishing The surface was observed by FE-SEM, and the number of compound particles having a particle diameter of 5 to 30 nm and a compound ratio of 20 to 30 μm ² or more and a particle diameter of more than 30 nm per 1 μm × 1 μm viewing area. The ratio is 1 / micrometer ² or less, It is characterized by the above-mentioned.

Description

Copper alloy material and its manufacturing method {COPPER ALLOY MATERIAL AND METHOD FOR PRODUCING SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy material and a method for producing the same, and more particularly, to a copper alloy material used for an electric and electronic component including a lead frame used in a semiconductor device and a method for producing the same.

A lead frame used for a semiconductor device such as an IC or an LSI is formed by pressing a copper alloy material, but at this time, work warping remains in the material. If this work warping remains, when the etching of the subsequent step is performed, warpage occurs in the material, and the dimensional accuracy of the lead pin spacing of the lead frame is lowered. For this reason, normally, the lead frame after press work is heat-processed at 400-450 degreeC, and a process warping is removed, but the crystal structure of a copper alloy recrystallizes at the time of this heat processing, and the strength of a copper alloy material tends to fall. It is known that there is. Thereby, the copper alloy material for electronic devices used for the lead frame needs to have a characteristic (heat resistance) in which the strength does not decrease even when the above heat treatment is performed.

In addition, the lead alloy copper alloy material has not only high strength for application to miniaturized parts, high conductivity for suppressing heat generation of the parts, but also good bending workability for enhancing the degree of freedom of part forming. It is also required to be humble.

As a copper alloy material that satisfies these requirements, a Cu-Ni-Sn-P-based alloy is widely provided. The Cu-Ni-Sn-P-based alloy can have a high strength, a high electrical conductivity, and good bending workability by depositing a Ni-P-based compound.

In Patent Documents 1 to 9, by controlling the size and distribution of the precipitate, not only tensile strength, electrical conductivity, bending workability, but also elasticity, stress relaxation resistance, press workability, corrosion resistance, plating property, solder wetting, migration resistance The combination of various properties such as antimigration and hot workability is considered.

Patent Document 1: Japanese Patent Application Laid-Open No. 4-154942 Patent Document 2: Japanese Patent Laid-Open No. 4-236736 Patent document 3: Unexamined-Japanese-Patent No. 10-226835 Patent Document 4: Japanese Patent Application Laid-Open No. 2000-129377 Patent Document 5: Japanese Patent Application Laid-Open No. 2000-256814 Patent Document 6: Japanese Patent Application Laid-Open No. 2001-262255 Patent Document 7: Japanese Patent Application Laid-Open No. 2001-262297 Patent Document 8: Japanese Patent Application Laid-Open No. 2006-291356 Patent Document 9: Japanese Patent Application Laid-Open No. 2007-100111

Although Cu-Ni-Sn-P alloy is an excellent alloy system having high strength, high electrical conductivity and good bending workability, it is hard to say that the heat resistance to the heat treatment at 400 to 450 ° C. performed on the lead frame after press working is sufficient. .

In Patent Literatures 1 to 9, all attempts have been made to improve various material properties. However, attention is not paid to improvement in heat resistance.

In view of the above circumstances, it is an object of the present invention to provide a copper alloy material having not only high strength, high electrical conductivity and good bending workability, but also more excellent heat resistance and a method for producing the same.

MEANS TO SOLVE THE PROBLEM This inventor studies the Cu-Ni-Sn-P type alloy used for electrical and electronic components including lead frames, and it is 0.05-1.2 mass% of Ni, 0.01-0.15 mass% of P, and 0.05-0.05 of Sn. It has an alloy composition containing 2.5% by mass, and the surface of the material after electropolishing was observed by FE-SEM, and the number ratio of the compound particles having a particle diameter of 5 to 30 nm per 1 µm x 1 µm was 20 pieces / µm ^2. As mentioned above, the number ratio of the compound particle whose particle diameter is more than 30 nm shall be 1 / micrometer ² or less, not only having high strength, high electrical conductivity, and favorable bending workability, but also obtaining the copper alloy material which has further better heat resistance. It has been found that the present invention can be completed.

That is, the summary structure of this invention is as follows.

(1) It contains 0.05-1.2 mass% of Ni, 0.01-0.15 mass% of P, and 0.05-2.5 mass% of Sn, the balance has the alloy composition which consists of Cu and an unavoidable impurity, The material surface after electrolytic polishing is FE-SEM Observed, the ratio of the number of compound particles having a particle diameter of 5 to 30 nm of 20 particles / μm ² or more and the number of compound particles having a particle diameter of more than 30 nm per 1 μm × 1 μm viewing area was 1 / A copper alloy material, characterized in that not more than ² ㎛.

(2) It contains 0.05-1.2 mass% of Ni, 0.01-0.15 mass% of P, and 0.05-2.5 mass% of Sn, and also Fe, Zn, Pb, Si, Mg, Zr, Cr, Ti, Mn and Co It contains at least one component selected from, 0.001-0.1 mass% of Fe, 0.001-0.5 mass% of Zn, 0.001-0.05 mass% of Pb, 0.001-0.1 mass% of Si, 0.001-0.3 mass%, Zr is 0.001-0.15 mass%, Cr is 0.001-0.3 mass%, Ti is 0.001-0.05 mass%, Mn is 0.001-0.2 mass%, Co is 0.001-0.2 mass%, and Mg, Zr, Cr, Ti, The total content in the case of containing 2 or more of Mn and Co is 0.001 to 0.5% by mass, the balance has an alloy composition composed of Cu and unavoidable impurities, and the surface of the material after electropolishing is observed by FE-SEM, and 1 µm x 1 µm. Wherein the number ratio of the compound particles having a particle diameter of 5 to 30 nm is 20 / μm ² or more and the number of the compound particles having a particle diameter of more than 30 nm is 1 / μm ² or less per field of view of the copper alloy. material.

(3) The copper alloy material according to the above (1) or (2), which contains 0.05 to 0.5 mass% of Sn and has a tensile strength of 400 MPa or more and a conductivity of 50% IACs or more.

(4) The copper alloy material according to the above (1) or (2), which contains more than 0.5% by mass and 2.5% by mass or less of Sn, having a tensile strength of 500 MPa or more and a conductivity of 25% IACS or more.

(5) The manufacturing method of the copper alloy material in any one of said (1)-(4) characterized by including the process of following (a)-(e).

(a) Melt casting process which makes cooling rate to 300 degreeC into 30 degreeC / min or more.

(b) The homogenization heat treatment process which heats up at 5 degree-C / min or more, and maintains at 600-1000 degreeC for 30 minutes-10 hours.

(c) Hot rolling process which makes cooling rate to 300 degreeC into 30 degreeC / min or more.

(d) Cold rolling process which makes processing rate into 80% or more.

(e) Annealing step of holding for 5 seconds to 10 hours at 350 ~ 600 ℃.

According to the present invention, Ni is contained 0.05 to 1.2% by mass, P is contained 0.01 to 0.15% by mass, and Sn is 0.05 to 2.5% by mass, and the balance has an alloy composition composed of Cu and unavoidable impurities. -Observed by SEM, the ratio of the number of compound particles having a particle diameter of 20-30 µm ² or more and the particle diameter of more than 30 nm was 1 per 1 µm × 1 µm viewing area. By setting it as the opening / micrometer <^2> or less, it became possible to provide the copper alloy material which combines not only high strength, high electrical conductivity, and favorable bending workability, but also more excellent heat resistance.

1 is a SEM photograph when the surface after electropolishing of the copper alloy material (Example 14) of the present invention is observed at a magnification of 50000 times by FE-SEM.
2 is a SEM photograph when the surface after electropolishing of Comparative Example 22 was observed at a magnification of 50000 times by FE-SEM.

EMBODIMENT OF THE INVENTION Hereinafter, preferable embodiment of the copper alloy material of this invention is described in detail.

(Component Composition of Copper Alloy Material)

The basic composition of the copper alloy material of this invention contains 0.05-1.2 mass% of Ni, 0.01-0.15 mass% of P, and 0.05-2.5 mass% of Sn, and remainder is Cu and an unavoidable impurity.

[Essential Content]

(Ni: 0.05-1.2 mass%)

Ni is an element which increases the strength by solid-solving in the mother phase and forming a compound with P. Moreover, Ni produces | generates P and a compound, and precipitates this product, and it has the effect which raises electrical conductivity and also improves heat resistance. However, when Ni content is less than 0.05 mass%, the effect cannot fully be exhibited, and when it exceeds 1.2 mass%, electrical conductivity falls remarkably. For this reason, Ni content was made into 0.05 to 1.2 mass%, Preferably it is 0.10 to 1.00 mass%, More preferably, it was 0.10 to 0.40 mass%.

(P: 0.01-0.15 mass%)

P is an element that contributes to an increase in strength, an increase in conductivity, and an improvement in heat resistance by generating a compound with Ni. However, when P content is less than 0.01 mass%, the effect cannot fully be acquired, and if it is more than 0.15 mass%, it will fall in the fall of electroconductivity and coarse (for example, particle diameter exceeding 30 nm) production | generation of a compound particle. This decreases the bending workability and decreases the production rate of a fine (eg, particle diameter of 5 to 30 nm) compound, resulting in a decrease in heat resistance and a decrease in workability. For this reason, P content was 0.01 to 0.15 mass%, Preferably it is 0.01 to 0.10 mass%, More preferably, it was 0.05 to 0.10 mass%.

(Sn: 0.05-2.5% by mass)

Sn is an element which contributes to the increase of strength and the improvement of heat resistance by solid solution in the mother phase. However, if Sn content is less than 0.05 mass%, the effect cannot fully be acquired, and if it is more than 2.5 mass%, electrical conductivity will fall and hot workability will deteriorate. For this reason, Sn content was made into 0.05-2.5 mass%. In particular, in the case where the conductivity is particularly important among the tensile strength and the electrical conductivity, when the Sn content is limited to 0.05 to 0.5 mass%, the tensile strength is preferably 400 MPa or more, and it is preferable at the point of having a high conductivity of 50% IACS or more, Moreover, especially when tensile strength is important, when Sn content is limited to more than 0.5 mass% and 2.5 mass% or less, it is preferable at the point which can provide high tensile strength of 500 Mpa or more with the electrical conductivity of 25% IACS or more.

[Optional additive component]

In the present invention, it is necessary to contain the above-mentioned Ni, P and Sn as the basic composition, but further selected from Fe, Zn, Pb, Si, Mg, Zr, Cr, Ti, Mn and Co as optional additives. You may selectively contain at least 1 component.

(Fe: 0.001-0.1 mass%)

Fe is an element which contributes to the increase of strength and the improvement of heat resistance by forming a compound with P. In order to exhibit this effect, it is preferable to make Fe content into 0.001 mass% or more. However, when the Fe content is more than 0.1% by mass, the material tends to be magnetic, and when the material is magnetic, there is a fear that the transmission characteristic of the transmission signal in the lead frame is deteriorated. For this reason, as for Fe content, it is preferable to set it as 0.001-0.1 mass%, 0.001-0.05 mass% is more preferable, and 0.001-0.01 mass% is further more preferable.

(Zn: 0.001-0.5 mass%)

Zn is an element which contributes to the increase in strength, the solder wettability, and the plating property by solid solution to the mother phase. In order to exert this effect, the Zn content is preferably 0.001% by mass or more. However, when Zn content is more than 0.5 mass%, there exists a tendency for electrical conductivity to fall. For this reason, it is preferable that Zn content is 0.001-0.5 mass%, 0.01-0.5 mass% is more preferable, 0.1-0.5 mass% is further more preferable.

(Pb: 0.001-0.05 mass%)

Pb is an element which contributes to the improvement of press workability, and in order to exhibit this effect, it is preferable to make Pb content 0.001 mass% or more. However, even if Pb content is more than 0.05 mass%, the further improvement of an effect is not recognized and it is preferable to suppress Pb content as much as possible from a viewpoint of environmental protection in recent years. For this reason, it is preferable to set it as 0.001-0.05 mass%, and, as for Pb content, 0.001-0.01 mass% is more preferable.

(Si: 0.001-0.1 mass%)

Si is an element which contributes to the increase of strength, and in order to exhibit this effect, it is preferable to make Si content into 0.001 mass% or more. However, when Si content is more than 0.1 mass%, deterioration of the bending workability by the fall of an electrical conductivity and formation of a coarse compound is feared. For this reason, 0.001-0.1 mass% is preferable, and, as for Si content, 0.01-0.1 mass% is more preferable.

(Mg: 0.001-0.3 mass%)

Mg is an element which contributes to the increase of strength and the improvement of heat resistance. For example, it contributes to the improvement of the stress relaxation resistance in the spring contact etc. of an electronic component. In order to exhibit such an effect, it is preferable to make Mg content into 0.001 mass% or more. However, when Mg content is more than 0.3 mass%, the fall of electrical conductivity and formation of the inclusion at the time of casting are concerned. For this reason, 0.001-0.3 mass% is preferable, and, as for Mg content, 0.01-0.3 mass% is more preferable.

(Zr: 0.001-0.15 mass%)

Zr is an element that contributes to an increase in strength and an improvement in heat resistance. For example, it contributes to the improvement of the stress relaxation resistance in the spring contact etc. of an electronic component. In order to exhibit such an effect, it is preferable to make Zr content 0.001 mass% or more. However, when Zr content is more than 0.15 mass%, a fall of electrical conductivity and a crack at the time of hot work are feared. For this reason, 0.001-0.15 mass% is preferable, and, as for Zr content, 0.01-0.1 mass% is more preferable.

(Cr: 0.001-0.3 mass%)

Cr is an element which contributes to an increase in strength and an improvement in heat resistance. In order to exert this effect, it is preferable to make the Cr content 0.001% by mass or more. However, when Cr content is more than 0.3 mass%, the fall of bending workability by the generation | occurrence | production of the product at the time of casting is feared. For this reason, 0.001-0.3 mass% is preferable, and, as for Cr content, 0.01-0.3 mass% is more preferable.

(Ti: 0.001-0.05 mass%)

Ti is an element that contributes to an increase in strength and an improvement in heat resistance. For example, it contributes to the improvement of the stress relaxation resistance in the spring contact etc. of an electronic component. In order to exhibit such an effect, it is preferable to make Ti content into 0.001 mass% or more. However, when Ti content is more than 0.05 mass%, an electroconductive fall and the casting surface abnormality of an ingot surface may be concerned. For this reason, 0.001-0.05 mass% is preferable, and, as for Ti content, 0.01-0.05 mass% is more preferable.

(Mn: 0.001-0.2 mass%)

Mn is an element which contributes to an increase in strength, an improvement in heat resistance and an improvement in hot workability. In order to exert this effect, the Mn content is preferably made 0.001% by mass or more. However, when Mn content is more than 0.2 mass%, the fall of electrical conductivity is concerned. For this reason, 0.001-0.2 mass% is preferable, and, as for Mn content, 0.01-0.2 mass% is more preferable.

(Co: 0.001-0.2 mass%)

Co is an element which contributes to the increase of strength and the improvement of hot workability, and in order to exhibit this effect, it is preferable to make Co content into 0.001 mass% or more. However, when Co content is more than 0.2 mass%, the fall of electrical conductivity is concerned. For this reason, 0.001-0.2 mass% is preferable, and, as for Co content, 0.01-0.2 mass% is more preferable.

(Total content in the case of containing 2 or more of Mg, Zr, Cr, Ti, Mn, and Co: 0.001-0.5 mass%)

Mg, Zr, Cr, Ti, Mn, and Co contribute to the increase of strength and the improvement of heat resistance by forming a compound with P. 0.001-0.5 mass% is preferable, as for the addition amount of such an element, 0.01-0.5 mass% is more preferable, and 0.1-0.5 mass% is further more preferable. When larger than 0.5 mass%, the fall of electrical conductivity and the fall of bending workability by coarse compound formation are concerned.

(Compound particles)

In the present invention, the surface of the material after electropolishing is observed by 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 / μm ² or more and particle diameter By setting the number ratio of the compound particles larger than 30 nm to 1 / μm ² or less, a copper alloy material having not only high strength, high electrical conductivity and good bending workability but also good heat resistance can be obtained. The term "compound particles" as used herein is a generic term for inclusions and creations formed during casting and precipitates formed after casting solidification. In addition, the particle diameter of a compound particle means the length of a long diameter. Recrystallization is suppressed by obtaining sufficient flux pinning by the fine compound particles when the ratio of the number of fine compound particles having a particle diameter of 5 to 30 nm is 20 / μm ^{2 or} more per viewing area of 1 μm × 1 μm. And good heat resistance can be obtained. On the other hand, when the ratio of the number of fine compound particles is less than 20 pieces / μm ² , good heat resistance cannot be obtained. Moreover, favorable bending workability can be obtained when the number ratio of the coarse compound particle whose particle diameter is more than 30 nm is 1 / micrometer <^2> or less. When the number ratio of the coarse compound particles exceeds 1 / µm ² , the coarse compound particles become the starting point of breakage, and the bending workability is significantly degraded. In addition, when many coarse compound particles are formed at this time, since the number ratio of the fine compound particles tends to decrease, there is a concern that the heat resistance may deteriorate. Conventionally, the dispersed state of a compound particle is observed using a transmission electron microscope (TEM), and is represented by the number and area ratio of a field of view in many cases, but such a numerical value depends on the thickness of a test piece. However, it is difficult to make the thickness of the test piece produced for TEM the same, and even if it measures with the same test piece, there may be a slightly different result depending on the number of measurements. For this reason, in this invention, the number ratio of the compound particle was evaluated using the field emission scanning electron microscope (FE-SEM) which does not originate in the thickness of a test piece.

(Method of manufacturing 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 → finishing rolling. Between each process, face-grinding, buff polishing, pickling, degreasing etc. can be performed suitably as needed. In addition, cold rolling and annealing can be repeatedly performed many times, and low-temperature annealing can 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 generate a large number of fine precipitates by subsequent cold rolling and annealing. The production method of the present invention can realize the improvement of material properties by appropriately adjusting the respective process conditions while being the same number of steps as in the prior art.

<Melting casting>

Melt casting can be carried out by a general method, but in the present invention, cooling to 300 ° C. at the time of casting at a cooling rate of 30 ° C./min or more suppresses generation and precipitation during cooling and coarser compounds. It is preferable at the point which suppresses generation | occurrence | production of particle | grains. It is because when the said cooling rate is smaller than 30 degreeC / min, creation and precipitation at the time of cooling cannot fully be suppressed, and a coarse compound particle tends to be easy to produce | generate.

<Homogenization Heat Treatment>

Homogenization heat processing is performed in order to make the coarse compound particle produced | generated by melt casting solid solution in a mother phase, and to make it into a solution state. It is preferable to hold a homogenization heat processing at 600-1000 degreeC for 30 minutes-10 hours. Conventionally, although the temperature increase rate of the homogenization heat treatment is not important, in this invention, it is necessary to control a temperature increase rate especially 5 degree-C / min or more, Preferably it is 10 degree-C / min or more in order to acquire the material structure prescribed | regulated. If the temperature increase rate is less than 5 DEG C / min, coarse compound particles formed by dissolution casting grow at the time of temperature increase, and the coarse compound particles are not easily dissolved in the mother phase by subsequent homogenization heat treatment, and the residual properties tend to remain. This is because the bending workability is deteriorated. Moreover, since the ratio of the number of fine compound particles also decreases, heat resistance also worsens. When the holding temperature satisfies at least one of less than 600 ° C. and the holding time is less than 30 minutes, coarse compound particles not dissolved in the mother phase tend to remain, resulting in deterioration in bending workability as a final property. It is because there exists a possibility that hot work crack may arise in the subsequent hot rolling process, when holding temperature is more than 1000 degreeC. Moreover, it is preferable to make an upper limit into 10 hours from a viewpoint of the saturation of a solution effect, and the time constraint in actual manufacture.

<Hot rolled>

It is preferable to perform hot rolling at 550-950 degreeC. In this invention, it is especially necessary to make cooling rate to 300 degreeC into 30 degreeC / min or more. This is because when the cooling rate up to 300 ° C. is less than 30 ° C./min, coarse compound particles are easily precipitated during cooling and adversely affect final properties.

<Cold rolled>

Cold rolling after hot rolling is preferably performed at a processing rate of 80% or more. This is because when the processing rate is less than 80%, no deformation is uniformly introduced into the material, and when the fine compound particles are precipitated by subsequent annealing, there is a fear that the precipitation state in the material may be different.

<Annealed>

It is preferable to hold annealing for 5 second-10 hours at 350-600 degreeC. If the temperature is shorter than the above range, the precipitation of fine compound particles is insufficient, and there is a fear of lowering the strength and conductivity, and if the temperature is longer than the above range, coarse compound particles are precipitated, and the bending workability deteriorates and the heat resistance deteriorates. Is concerned.

<Finish rolling>

Although the processing rate of finish rolling is not specifically limited, In order to acquire favorable bending workability, it is preferable to set it as 60% or less.

<Low temperature annealing>

After finish rolling, low-temperature annealing at 250-400 degreeC for 2 second-5 hours can be performed. By low temperature annealing, the elasticity and stress relaxation resistance of the material can be improved. If the temperature is shorter than the above range, the effect of low temperature annealing may not be obtained, and if the temperature is longer than the above range, fine compound particles may grow coarse and adversely affect bending workability and heat resistance. . In addition, there is a fear that the recrystallization of the material proceeds and the desired strength cannot be obtained.

The copper alloy material of the present invention can combine not only high strength, high conductivity and good bending workability but also heat resistance by controlling the size and amount of the compound particles of the Cu-Ni-Sn-P-based copper alloy having a predetermined alloy composition. have. For this reason, the copper alloy material of the present invention is suitable for use in electric and electronic components including lead frames.

EXAMPLE

Hereinafter, although this invention is demonstrated in more detail according to an Example, this invention is not limited to them.

(Examples 1-26 and Comparative Examples 1-22)

Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to this.

The alloy components are melted and cast while cooling at a cooling rate of 30 ° C./min or more to 300 ° C., and after producing an ingot having the ingredient composition shown in Table 1, the temperature is raised at a temperature rising rate shown in Table 2 and 30 at 600 to 1000 ° C. Homogenization heat treatment maintained in minutes for 10 hours, followed by hot rolling. After hot rolling, it cooled at the cooling rate to 300 degreeC shown in Table 2, after that, the surface oxide layer was removed by surface roughing, and cold rolling was performed at 80% or more of work rate. Thereafter, annealing is performed at 350 to 600 ° C. for 5 seconds to 10 hours, and 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 plate thickness of 0.5 mm was produced.

The following evaluation was performed about the test material manufactured in this way.

(Tissue observation)

After electrolytic polishing 20 micrometers of the surface of the test piece (size: 20 mm x 20 mm) collected from each copper alloy material (test material) manufactured by the phosphate type aqueous solution, the material surface was observed 10000-100000 times by FE-SEM. . Observation observed the field of 1 micrometer x 1 micrometer arbitrarily 3 o'clock, and the number of the fine compound particles whose particle diameters are 5-30 nm which exist in the viewing range, and a coarse particle diameter exceeding 30 nm are large. The number of compound particles was measured. Then, the measured number was converted into the ratio of the number per viewing area of 1 micrometer x 1 micrometer (1 micrometer <^2> ). The converted number ratio was rounded off, and the fine compound particles were represented by integers, and the coarse compound particles were represented by two decimal places.

(Measurement of tensile strength)

Tensile strength is taken from each specimen, three specimens of No. 5 specified in annex B of JIS Z2241: 2011 in the bar along the rolling parallel direction, and the "metallic material tensile test method" prescribed in JIS Z2241: 2011. Three measurements were made according to the procedure. The average value of those tensile strengths is shown in Table 2.

(Measurement of conductivity)

In the thermostat maintained at 20 ° C (± 0.5 ° C), the resistivity was measured by the four-terminal method, and the electrical conductivity was calculated from the measured resistivity. In addition, the distance between terminals was 100 mm.

(Bending workability)

According to JCBA T307: 2007, a bending test was conducted. The test piece of 10 mm of plate | board width was W-wounded with the inner bending radius of 0.5 mm and the bending angle of 90 degrees with respect to the direction (G.W. direction) in which a bending axis becomes perpendicular | vertical to a rolling direction, and the direction (B.W. direction) to become parallel, respectively. In the electric and electronic parts including the lead frame, bending in both the GW and BW directions is assumed, so that the surface of the bend vertices after bending is observed with an optical microscope, and cracks occur in both the GW and BW directions. The thing which was not good evaluated the bending workability good (A), and the thing which generate | occur | produced as bending workability defect (D). The evaluation results are shown in Table 2.

(Heat resistance)

Heat resistance is good when the test piece is put into the salt bath heated to 450 degreeC, the heat processing to take out and water-cools after 5 minutes passes, and the value after dividing the hardness after heat processing by the hardness before heat processing is 0.8 or more (A), 0.8 Less than was evaluated as heat resistance defect (D). The evaluation results are shown in Table 2. In addition, hardness was measured according to the Vickers Hardness Test-test method prescribed | regulated to JISZ2244: 2009. In addition, since the film | membrane was formed in the surface which contacted the salt bath, the material after heat processing measured hardness after removing by pickling.

From the results shown in Table 1 and Table 2, all of Examples 1 to 13 having a Sn concentration in the range of 0.05 to 0.5 mass% have tensile strengths of 432 to 492 MPa and 400 MPa or more, and electrical conductivity of 50 to 77% IACs and 50%. It is more than IACS and can obtain favorable bending workability (A) and favorable heat resistance (A). On the other hand, Comparative Examples 1-9 in which the component composition shown in Table 1 is outside the range of this invention, and Comparative Examples 10 and 11 whose manufacturing conditions shown in Table 2 are outside the range of this invention are all tensile strength, electrical conductivity, bending workability, and heat resistance. And at least one of manufacturability was inferior.

In addition, all of Examples 14-26 whose Sn concentration is more than 0.5 mass% and 2.5 mass% or less have tensile strengths of 512-593 MPa and 500 MPa or more, electrical conductivity is 27-38% IACS and 25% IACS or more, and is favorable. Bending workability (A) and good heat resistance (A) can be obtained. On the other hand, Comparative Examples 12-20 in which the component composition shown in Table 1 is outside the range of this invention, and Comparative Examples 21 and 22 in which the manufacturing conditions shown in Table 2 are outside the range of this invention are all tensile strength, electrical conductivity, bending workability, and heat resistance. And at least one of manufacturability was inferior.

1 and 2 show SEM photographs when the surfaces after electropolishing of the copper alloy materials of Example 14 and Comparative Example 22 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, it can be seen that the compound particles become coarse.

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

Claims (5)

It contains 0.05-1.2 mass% of Ni, 0.01-0.15 mass% of P, and 0.05-2.5 mass% of Sn, the balance has the alloy composition which consists of Cu and an unavoidable impurity, The surface of the material after electrolytic polishing was observed by FE-SEM, , The number ratio of the compound particles having a particle diameter of 5 to 30 nm per 20 m / m ² or more, and the number ratio of the compound particles having a particle diameter of more than 30 nm are 0 to 0.33 pieces / μm per 1 μm × 1 μm viewing area. Copper alloy material, characterized in that 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, further selected from Fe, Zn, Pb, Si, Mg, Zr, Cr, Ti, Mn and Co It contains at least one component, Fe is 0.001-0.1 mass%, Zn is 0.001-0.5 mass%, Pb 0.001-0.05 mass%, Si 0.001-0.1 mass%, Mg 0.001-0.3 mass%, Zr 0.001 0.15 mass%, Cr 0.001-0.3 mass%, Ti 0.001-0.05 mass%, Mn 0.001-0.2 mass%, Co 0.001-0.2 mass%, and Mg, Zr, Cr, Ti, Mn and Co In the case of containing 2 or more, the total content is 0.001 to 0.5% by mass, the balance has an alloy composition composed of Cu and unavoidable impurities, the surface of the material after electropolishing is observed by FE-SEM, and the viewing area of 1 μm × 1 μm. The copper alloy material characterized in that the number ratio of the compound particles having a particle diameter of 5 to 30 nm is 20 pieces / μm ² or more, and the number ratio of the compound particles having a particle diameter of more than 30 nm is 0 to 0.33 pieces / μm ² . .
The copper alloy material according to claim 1 or 2, which contains 0.05 to 0.5 mass% of Sn, has a tensile strength of 400 MPa or more and a conductivity of 50% IACs or more.
The copper alloy material according to claim 1 or 2, wherein Sn is more than 0.5% by mass and 2.5% by mass or less, and the tensile strength is at least 500 MPa and the conductivity is at least 25% IACS.
The manufacturing method of the copper alloy material of Claim 1 or 2 including the process of following (a)-(e).
(a) Melt casting process which makes cooling rate to 300 degreeC into 30 degreeC / min or more.
(b) The homogenization heat treatment process which heats up at 5 degree-C / min or more and hold | maintains at 600-1000 degreeC for 30 minutes-10 hours.
(c) Hot rolling process which makes cooling rate to 300 degreeC into 30 degreeC / min or more.
(d) Cold rolling process with a processing rate of 80% or more.
(e) Annealing process held at 350 to 600 ° C. for 5 seconds to 10 hours.

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