JP2017226897A - Copper alloy material, method for manufacturing copper alloy material, lead frame and connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for further improving conductivity, strength, stress relaxation resistance in copper alloy materials.SOLUTION: Provided is a copper alloy containing 0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus, 0.01 mass% or more and 0.2 mass% or less of magnesium, and 0.05 mass % to 0.2 mass% or less of tin, and the balance is composed of copper and inevitable impurities, and in which the conductivity is 72% IACS or more, the 0.2% proof stress is 520 MPa or more, and the stress relaxation rate after heating for 1000 hours under 150°C condition is 25% or less.SELECTED DRAWING: None

Description

  The present invention relates to a copper alloy material, a copper alloy material manufacturing method, a lead frame, and a connector.

  A copper alloy material is used for the base material of the lead frame, the conductor portion of the connector, and the like. Such a copper alloy material is required to have high conductivity, high strength, and high stress relaxation resistance. As such a copper alloy material, a copper alloy material formed of a Cu—Fe—Ni—P alloy or a copper alloy material formed by adding Mg or the like to a Cu—Fe—Ni—P alloy has been proposed. (For example, refer patent documents 1-4). The latter copper alloy material has, for example, a conductivity of 70% IACS or more, a 0.2% proof stress of 500 MPa or more, and a stress relaxation rate after heating for 1000 hours at 150 ° C. of 30% or less, It can be said that the copper alloy material has high conductivity, high strength, and high stress relaxation resistance.

JP 2000-017355 A JP 2012-1781 A JP 2006-011437 A Japanese Patent Application Laid-Open No. 2006-14165

  However, even with the above-described copper alloy material, depending on the use of the copper alloy material, the properties of conductivity, strength, and stress relaxation resistance may be insufficient, and further improvement of these properties is desired. Yes.

  An object of this invention is to provide the technique which further improves electroconductivity, intensity | strength, and stress relaxation resistance in a copper alloy material.

According to one aspect of the invention,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
There is provided a copper alloy material having an electrical conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C.

According to another aspect of the invention,
A casting process for casting the ingot;
A hot rolling step of hot rolling the ingot to form a hot rolled material;
A first heat treatment step of performing a heat treatment on the hot rolled material to form a heat treated material;
A cold rolling step of performing cold rolling on the heat treated material to form a cold rolled material, and
In the casting process,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing the magnesium of 01% by mass or more and 0.2% by mass or less, and tin of more than 0.05% by mass and 0.2% by mass or less, and casting the ingot of which the balance is made of copper and inevitable impurities;
In the first heat treatment step,
The hot-rolled material is heat-treated by holding it at a temperature of 450 ° C. or higher and 550 ° C. or lower for 3 hours or more,
In the cold rolling process,
Cold rolling on the heat treatment material and annealing performed at a temperature lower than the temperature at which recrystallization occurs in the material to be rolled are alternately repeated a predetermined number of times,
Copper alloy material that forms a copper alloy material having a conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C. A manufacturing method is provided.

According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
Provided is a lead frame having a base material having an electrical conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after 1000 hours of heating at 150 ° C. The

According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
Provided is a connector having a conductor portion having an electrical conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C. .

  ADVANTAGE OF THE INVENTION According to this invention, the technique which further improves electroconductivity, intensity | strength, and stress relaxation resistance in a copper alloy material can be provided.

<One Embodiment of the Present Invention>
(1) Structure of copper alloy material The structure of the copper alloy material concerning one Embodiment of this invention is demonstrated.

  The copper alloy material according to the present embodiment contains a predetermined amount of iron (Fe), nickel (Ni), phosphorus (P), magnesium (Mg), and tin (Sn), with the balance being Cu and inevitable impurities. Yes. Further, the copper alloy material according to the present embodiment has a conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate after heating for 1000 hours at 150 ° C. is 25. % Or less.

  It is preferable to use oxygen-free copper (OFC) or the like as Cu which is a base material of the copper alloy material (which becomes a base phase of the copper alloy material).

As described above, the copper alloy material according to the present embodiment contains a predetermined amount of Fe, a predetermined amount of Ni, and a predetermined amount of P. Thus, a copper alloy material in a compound of Fe and P (Fe-P compounds such as _Fe 2 P) and a compound of Ni and P (Ni-P compounds such as _{Ni 5 P 2, Ni 2 P} ) and the Precipitation (dispersion precipitation) occurs simultaneously. By precipitating the Fe-P compound and the Ni-P compound P compound in the copper alloy material, the strength of the copper alloy material can be improved by the synergistic effect of the Fe-P compound and the Ni-P compound.

  From the viewpoint of further improving the strength of the copper alloy material, it is conceivable to increase the contents of Fe and Ni in the copper alloy material in order to increase the precipitation amount of the Fe—P compound and the Ni—P compound. However, if the contents of Fe and Ni are excessively increased, the amounts of Fe and Ni dissolved in the copper alloy material increase without generating Fe-P compounds and Ni-P compounds. For this reason, the electroconductivity of a copper alloy material may fall. Thus, in the Cu—Fe—Ni—P-based copper alloy material, there is a trade-off relationship between improvement in conductivity and improvement in strength.

  Therefore, in this embodiment, in order to suppress the decrease in conductivity while maintaining a predetermined strength and improve the strength and the conductivity in a balanced manner, the influence on the conductivity is greater than that of Fe, that is, the conductivity is greater than that of Fe. The content of Ni, which tends to lower the properties, is reduced. The contents of Fe, Ni, and P, and the ratio of the mass of Fe to the mass of Ni are preferably as follows.

  The content of Fe in the copper alloy material is, for example, 0.2% by mass or more and 0.6% by mass or less, preferably 0.3% by mass or more and 0.5% by mass or less.

  If the Fe content is less than 0.2% by mass, the precipitation amount of the Fe-P compound decreases, and the strength of the copper alloy material is set to a predetermined strength unless the content of other components such as Ni is increased. There are things that cannot be done. That is, the strength improvement effect by the Fe—P compound may not be obtained.

  By making the Fe content 0.2% by mass or more, a certain amount of Fe—P compound can be generated and precipitated in the copper alloy material, and the strength improvement effect by the Fe—P compound can be obtained. it can. For example, the 0.2% proof stress of the copper alloy material can be set to 520 MPa or more. By making the content of Fe 0.3% by mass or more, the strength improvement effect by the Fe—P compound can be surely obtained.

  However, if the Fe content exceeds 0.6% by mass, the amount of Fe dissolved in the copper alloy material without generating an Fe—P compound may increase. For this reason, the electroconductivity of a copper alloy material may fall.

  By making Fe content 0.6 mass% or less, it can suppress that Fe dissolves in a copper alloy material, and can suppress the electroconductive fall by Fe. For example, the conductivity of the copper alloy material can be 72% IACS or higher. By making Fe content 0.5 mass% or less, it can suppress reliably that Fe dissolves in a copper alloy material, and the electroconductive fall by Fe can be suppressed reliably.

  The content of Ni in the copper alloy material is, for example, 0.02% by mass or more and 0.06% by mass or less, and preferably 0.03% by mass or more and 0.05% by mass or less.

  If the Ni content is less than 0.02% by mass, the precipitation amount of the Ni-P compound will decrease, and unless the content of other components such as Fe is increased, the strength of the copper alloy material will be set to a predetermined strength. There are things that cannot be done. That is, the strength improvement effect by the Ni—P compound may not be obtained.

  By making the Ni content 0.02% by mass or more, a certain amount of Ni—P compound can be generated and precipitated in the copper alloy material, and the strength improvement effect by the Ni—P compound can be obtained. it can. For example, the 0.2% proof stress of the copper alloy material can be set to 520 MPa or more. By setting the Ni content to 0.03% by mass or more, the strength improvement effect by the Ni-P compound can be reliably obtained.

  However, if the Ni content exceeds 0.06% by mass, the amount of Ni dissolved in the copper alloy material without generating a Ni-P compound may increase. For this reason, the electroconductivity of a copper alloy material may fall.

  By making content of Ni 0.06 mass% or less, it can suppress that Ni dissolves in a copper alloy material, and can suppress the electroconductive fall by Ni. For example, the conductivity of the copper alloy material can be 72% IACS or higher. By making Ni content 0.05 mass% or less, it can suppress reliably that Ni dissolves in a copper alloy material, and can suppress the electroconductive fall by Ni reliably.

  The content of P in the copper alloy material is, for example, from 0.07% by mass to 0.3% by mass, and preferably from 0.1% by mass to 0.2% by mass.

  If the content of P is less than 0.07% by mass, the amount of precipitation of Fe—P compound and Ni—P compound will decrease, and the content of other components such as Mg and Sn will not increase. In some cases, it is not possible to achieve a predetermined strength. That is, the strength improvement effect by a Fe-P compound and a Ni-P compound may not be acquired.

  By making the P content 0.07% by mass or more, a certain amount of Fe—P compound and Ni—P compound can be generated and precipitated in the copper alloy material, and Fe—P compound, Ni The strength improvement effect by the -P compound can be obtained. For example, the 0.2% proof stress of the copper alloy material can be set to 520 MPa or more. By making the P content 0.1% by mass or more, the strength improvement effect by the Fe—P compound and the Ni—P compound can be surely obtained.

  However, when the P content exceeds 0.3% by mass, the amount of P dissolved in the copper alloy material without the formation of the Fe—P compound or Ni—P compound may increase. For this reason, the electroconductivity of a copper alloy material may fall.

  By making content of P 0.3 mass% or less, it can suppress that P dissolves in a copper alloy material, and can suppress the electroconductive fall by P. For example, the conductivity of the copper alloy material can be 72% IACS or higher. By making the P content 0.2 mass% or less, it is possible to reliably suppress the decrease in conductivity due to P.

  From the viewpoint of suppressing the occurrence of excess or deficiency of the Ni content (mass) with respect to the Fe content (mass), the copper alloy material is within the above-mentioned predetermined ranges of Fe and Ni, respectively. The ratio of the mass of Fe to the mass of Ni (Fe / Ni) is, for example, 5 or more and 10 or less, preferably 7 or more and 10 or less.

  As described above, Ni has a greater influence on the conductivity than Fe, and is more likely to lower the conductivity than Fe. For this reason, when Fe / Ni is less than 5, that is, when the Ni content is relatively larger than the Fe content, the strength can be further increased, but the decrease in conductivity due to Ni cannot be suppressed. Sometimes. That is, in the copper alloy material, the balance between strength and conductivity may be lost.

  By setting Fe / Ni to 5 or more, a decrease in conductivity due to Ni can be suppressed, and the strength and conductivity of the copper alloy material can be improved in a balanced manner. By setting Fe / Ni to 7 or more, it is possible to reliably suppress a decrease in conductivity due to Ni, and to improve the strength and conductivity of the copper alloy material in a balanced manner.

  However, when Fe / Ni exceeds 10, the content of Ni is relatively reduced, and thus the precipitation amount of the Ni-P compound may be reduced. The strength improvement effect by the Ni—P compound is larger than the strength improvement effect by the Fe—P compound. For this reason, the strength improvement effect by a Ni-P compound is not fully acquired, and the intensity | strength of a copper alloy material may not be made into predetermined intensity | strength. As a result, the balance between the strength and conductivity of the copper alloy material may be lost.

  By making Fe / Ni 10 or less, a certain amount of Ni—P compound can be reliably generated and precipitated in the copper alloy material, and the strength improvement effect by the Ni—P compound can be reliably obtained. . As a result, the strength and conductivity of the copper alloy material can be improved in a balanced manner.

  As described above, in this embodiment, the Ni content is relatively smaller than the Fe content. When the Ni content is reduced, the amount of Ni-P compound deposited is reduced. Since the Ni-P compound has a higher effect of improving the strength of the copper alloy material than the Fe-P compound, the strength of the copper alloy material may be insufficient when the amount of precipitation of the Ni-P compound decreases.

  Therefore, the copper alloy material according to the present embodiment further contains a predetermined amount of Mg together with Fe, Ni, and P. Mg has the effect of improving the strength of the copper alloy material by being dissolved in the copper alloy, that is, by being precipitated alone in the parent phase without forming a compound with other elements, and more copper than Ni. It is a component that does not easily lower the conductivity of the alloy material. By including such Mg in the copper alloy material together with Fe, Ni, and P, the strength of the copper alloy material can be set to a predetermined strength even when the content of Ni is reduced as described above. At the same time, the decrease in conductivity can be suppressed. That is, by including Mg in the copper alloy material, it is possible to compensate for the decrease in strength of the copper alloy material due to a decrease in the precipitation amount of the Ni-P compound, and by reducing the Ni content, A decrease in conductivity can be suppressed.

  The content of Mg in the copper alloy material is, for example, 0.01% by mass or more and 0.2% by mass or less, preferably 0.03% by mass or more and 0.1% by mass or less.

  If the Mg content is less than 0.01% by mass, Mg is bound to oxygen (O) and sulfur (S), which are inevitable impurities, so that the amount of Mg dissolved in the copper alloy material is reduced. May decrease. In addition, MgO, MgS, etc. produced | generated when Mg couple | bonds with O, S, etc. do not have the strength improvement effect of a copper alloy material. As a result, the strength improvement effect by containing Mg may not be obtained.

  By setting the Mg content to 0.01% by mass or more, even if a part of Mg is combined with O, S, or the like, a certain amount of Mg can be dissolved in the copper alloy material. Thereby, the strength improvement effect by containing Mg can be acquired. For example, the 0.2% proof stress of the copper alloy material can be set to 520 MPa or more. By making the Mg content 0.03% by mass or more, the strength improvement effect by containing Mg can be surely obtained.

  As described above, Mg is a component that is less likely to lower the conductivity than Ni. However, if the Mg content exceeds 0.2% by mass, the amount of Mg dissolved in the copper alloy material increases excessively, and the conductivity of the copper alloy material may be reduced by Mg.

  By making the content of Mg 0.2 mass% or less, it is possible to suppress a decrease in conductivity due to Mg. As a result, the strength of the copper alloy material can be improved while suppressing a decrease in the conductivity of the copper alloy material. For example, the 0.2% proof stress can be 520 MPa or more while maintaining the conductivity of the copper alloy material at 72% IACS or more. By making the content of Mg 0.1% by mass or less, it is possible to reliably suppress a decrease in conductivity due to Mg.

  Further, as described above, the copper alloy material according to the present embodiment further contains Sn together with Fe, Ni, P, and Mg. Sn is a component (element) added mainly for the purpose of improving the stress relaxation resistance of the copper alloy material. Sn is a component that can improve the stress relaxation resistance of the copper alloy material by dissolving in the copper alloy material.

  This is because Sn is an element having an atomic radius larger than the atomic radius of Cu as a parent phase. When an element having an atomic radius larger than the atomic radius of Cu as the parent phase is taken into the crystal of the copper alloy material, lattice distortion occurs in the crystal of the copper alloy material. However, elements having a large atomic radius tend to be associated with vacancies in the crystal of the copper alloy material so as to reduce the lattice distortion. When the vacancies are combined with an element having an atomic radius larger than that of Cu, the volume of the vacancies decreases.

  The stress relaxation is a phenomenon in which the elastic strain changes to a plastic strain with the passage of time and a stress decreases with a constant strain applied to the copper alloy material. Such stress relaxation proceeds by atomic diffusion and dislocation movement at the atomic level. Therefore, in order to improve the stress relaxation resistance of the copper alloy material, it is necessary to suppress the diffusion of Cu atoms and the movement of dislocations.

  The diffusion of Cu atoms proceeds as Cu atoms jump and move through vacancies in the crystal (via vacancies). For this reason, for example, even when a copper alloy material is used in a high temperature environment and Cu atoms are to diffuse, Cu atoms can be reduced by adding Sn to the copper alloy material as described above to reduce the void volume. It becomes difficult to enter the hole. This makes it difficult for Cu atoms to jump and move through the vacancies, making it difficult for Cu atoms to diffuse. That is, diffusion of Cu atoms can be suppressed.

  In addition, elements having a large atomic radius incorporated into the crystal of the copper alloy material are segregated around the dislocations in the copper alloy material so as to reduce the lattice distortion of the crystal of the copper alloy material. This state is called a Cottrell atmosphere. The Cottrell atmosphere is energetically stable. When a copper alloy material containing Sn is used, for example, in a high temperature environment and dislocations are about to move, the dislocations must move while maintaining the state of the Cottrell atmosphere. For this reason, it is difficult for dislocations to move, that is, the movement of dislocations can be suppressed.

  As described above, the diffusion of Cu atoms and the movement of dislocations can be suppressed by containing Sn in the copper alloy material. As a result, the stress relaxation resistance of the copper alloy material can be improved.

  In addition to Sn, there are elements having an atomic radius larger than that of Cu atoms. However, the present inventors have confirmed that Sn is more effective in improving the stress relaxation resistance of the copper alloy material than other elements having an atomic radius larger than that of Cu atoms.

  Moreover, Sn also shows a high strength improvement effect by dissolving in a copper alloy. Therefore, the strength of the copper alloy material can be further improved by containing Sn in the copper alloy material. For example, even when the Ni content is reduced as described above, the strength of the copper alloy material can be ensured to a predetermined strength.

  The Sn content is, for example, more than 0.05% by mass and 0.2% by mass or less, preferably 0.08% by mass or more and 0.15% by mass or less.

  When the Sn content is 0.05% by mass or less, the stress relaxation resistance may be insufficient. Further, unless the content of other elements of Fe, Ni, and Mg is increased, the strength of the copper alloy material may be lowered.

  By making the Sn content more than 0.05% by mass, the stress relaxation resistance can be sufficiently improved. Specifically, the stress relaxation rate after heating for 1000 hours under the condition of 150 ° C. can be 25% or less. Further, the strength of the copper alloy material can be improved, and the strength of the copper alloy material can be set to a predetermined strength without increasing the content of other elements of Fe, Ni, and Mg. For example, the 0.2% proof stress of the copper alloy material can be set to 520 MPa or more. By making the Sn content 0.08% by mass or more, the stress relaxation resistance and strength of the copper alloy material can be reliably improved.

  As described above, Sn is a component that has a high effect of improving stress relaxation resistance and a high effect of improving strength, but is also a component that tends to lower the conductivity. For this reason, if the Sn content exceeds 0.2 mass% and the amount of Sn dissolved in the copper alloy material increases, the conductivity of the copper alloy material may decrease.

  By making the content of Sn 0.2 mass% or less, it is possible to suppress a decrease in conductivity of the copper alloy material due to Sn. As a result, the stress relaxation resistance and strength of the copper alloy material can be improved without reducing the conductivity of the copper alloy material. By making the Sn content 0.15% by mass or less, it is possible to reliably suppress a decrease in conductivity due to Sn.

  Furthermore, the copper alloy material may contain zinc (Zn). Thereby, when a copper alloy material is used, for example, as a base material of a lead frame or a conductor part of a connector, the copper alloy material and the solder layer are peeled due to the solid solution of Zn in the copper alloy material. Can be suppressed. That is, solderability (solder adhesion) can be improved. As a result, the reliability with respect to soldering can be improved. Reliability for such soldering is one of the important characteristics particularly for the lead frame.

  When the copper alloy material contains Zn, the content of Zn is preferably 0.001 mass% or more and 0.005 mass% or less, for example.

  If the Zn content is less than 0.001% by mass, the amount of Zn dissolved in the copper alloy material may decrease due to bonding of Zn to O and S which are inevitable impurities. is there. In addition, ZnO, ZnS, etc. produced | generated when Zn couple | bonds with O, S, etc. do not have an effect which improves solderability. As a result, the improvement effect of solderability by containing Zn may not be obtained.

  By setting the Zn content to 0.001% by mass or more, even if a part of Zn is combined with O, S or the like, a certain amount of Zn can be dissolved in the copper alloy material. Thereby, the improvement effect of the solderability by containing Zn can be acquired.

  However, if the Zn content exceeds 0.005% by mass, the amount of Zn dissolved in the copper alloy material increases, and the conductivity of the copper alloy material may be reduced by Zn.

  By making Zn content 0.005 mass% or less, solderability can be improved, without reducing the electroconductivity of a copper alloy material.

(2) Method for Producing Copper Alloy Material Next, the method for producing a copper alloy material according to the present embodiment will be described by illustrating a melting casting method.

(Casting process)
First, oxygen-free copper as a base material is melted in a nitrogen atmosphere using, for example, a high-frequency melting furnace or the like to generate a molten copper. In the molten copper, Fe, Ni, P, Mg and Sn are added to form a molten copper alloy. At this time, the Fe content is 0.2 mass% or more and 0.6 mass% or less, the Ni content is 0.02 mass% or more and 0.06 mass% or less, and the P content is 0.00. It becomes 07 mass% or more and 0.3 mass% or less, Mg content becomes 0.01 mass% or more and 0.2 mass% or less, Sn content exceeds 0.05 mass% and is 0.2 mass%. The addition amount (input amount) of Fe, Ni, P, Mg, and Sn is adjusted so as to be as follows. Moreover, it is preferable to further adjust the addition amounts of Fe and Ni so that the ratio of Fe mass to Ni mass (Fe / Ni) is 5 or more and 10 or less. Further, the molten copper alloy may further contain Zn. In this case, the amount of Zn added is adjusted so that the Zn content is 0.001 mass% or more and 0.005 mass% or less. The molten copper alloy is poured into a mold and cooled to cast an ingot having a predetermined composition.

(Hot rolling process)
The above ingot is heated to a predetermined temperature (for example, 900 ° C. or more and 1000 ° C. or less), and hot rolling is performed on the ingot at a predetermined processing degree (for example, the total processing degree is 60% or more and 95% or less). A hot rolled material having a predetermined thickness is formed. The hot-rolled material in this specification refers to a copper alloy plate material formed by performing a hot rolling process.

(First heat treatment process (aging process))
After the hot rolling process is completed, the hot rolled material is subjected to heat treatment (aging treatment) to form a heat treated material. The heat treatment material in this specification refers to a copper alloy plate material after the first heat treatment step is performed.

  As described above, the ingot from which the finally formed copper alloy material (hereinafter, also simply referred to as “copper alloy material”) contains Sn, which is a component that easily lowers conductivity. . For this reason, it is possible to sufficiently disperse and precipitate the Fe—P compound and the Ni—P compound in the copper alloy material by sufficiently aging the hot rolled material at an appropriate temperature, and the Fe—P compound, Without generating the Ni—P compound, the amount of Fe, Ni, and P dissolved in the copper alloy material is reduced as much as possible, which causes a decrease in conductivity other than Sn. Thereby, even if it is a case where Sn is contained, the electroconductive fall by the element which dissolves in a copper alloy material can be suppressed to the minimum. Further, high conductivity can be maintained even after the cold rolling process described later.

  In the first heat treatment step, the hot rolled material is heated at a temperature of 450 ° C. or higher and 550 ° C. or lower, that is, the hot rolled material is heated to a temperature of 450 ° C. or higher and 550 ° C. or lower, for example. In this state, heat treatment is performed for 3 hours or more, preferably 8 hours or more. As a result, the Fe—P compound and Ni—P compound can be sufficiently dispersed and precipitated to improve the strength of the copper alloy material, and the dissolution of Fe, Ni, and P in the copper alloy material is suppressed. It is possible to suppress a decrease in conductivity of the copper alloy material.

  When the heat treatment temperature (heating temperature) is less than 450 ° C. or the heat treatment time (heating (holding) time) is less than 3 hours, a predetermined amount of Fe, Ni, P is contained in the copper alloy. Even in this case, the Fe—P compound and Ni—P compound may not be sufficiently dispersed and precipitated in the copper alloy material. For this reason, in a copper alloy material, the strength improvement effect by a Fe-P compound and a Ni-P compound is not acquired, As a result, the intensity | strength of a copper alloy material may not be made into predetermined intensity | strength. Further, since Fe—P compound and Ni—P compound cannot be sufficiently dispersed and precipitated, Fe, Ni, which dissolves in the copper alloy material without generating Fe—P compound and Ni—P compound, The amount of P may increase. As a result, the conductivity of the copper alloy material may decrease.

  By setting the temperature of the heat treatment to 450 ° C. or more and setting the heat treatment time to 3 hours or more, the Fe—P compound and the Ni—P compound can be sufficiently dispersed and precipitated. As a result, Fe, It can suppress that Ni and P dissolve. Thereby, in a copper alloy material, the strength improvement effect by a Fe-P compound and a Ni-P compound can be obtained, and the strength of the copper alloy material can be set to a predetermined strength, and the conductivity of the copper alloy material can be increased. Reduction can be suppressed. Further, by setting the heat treatment time to 8 hours or more, the Fe—P compound and the Ni—P compound can be more sufficiently dispersed and precipitated. As a result, Fe, Ni, and P are dissolved in the copper alloy material. Can be reliably suppressed. Thereby, in a copper alloy material, while the strength improvement effect by a Fe-P compound and a Ni-P compound can be acquired reliably, the electroconductive fall of a copper alloy material can be suppressed reliably.

  However, when the temperature of the heat treatment exceeds 550 ° C., a phenomenon occurs in which the Fe-P compound and Ni—P compound that are dispersed and precipitated again form a solid solution, and the amount of Fe and Ni remaining in a solid solution state in the heat treatment material increases. There is. For this reason, the amount of Fe, Ni, and P dissolved in the copper alloy material increases, and as a result, the conductivity of the copper alloy material may decrease. Moreover, when the temperature of heat processing exceeds 550 degreeC, the recrystallization of Cu which is a parent phase will advance, and the intensity | strength of heat processing material may fall.

  The above-mentioned phenomenon can be suppressed by setting the temperature of the heat treatment to 550 ° C. or lower. Thereby, it can suppress that Fe, Ni, and P dissolve in a copper alloy material, As a result, the electroconductive fall of a copper alloy material can be suppressed. Moreover, it can suppress that recrystallization of Cu which is a mother phase progresses, and can suppress that the intensity | strength of heat processing material (copper alloy material) falls.

(Cold rolling process)
After the first heat treatment step is completed, the heat treated material is subjected to predetermined cold rolling to form a cold rolled material having a predetermined thickness. In the cold rolling step, for example, cold rolling for the heat treated material and annealing for the material to be rolled are alternately repeated a predetermined number of times. The cold rolling process is preferably terminated by cold rolling rather than annealing. The cold-rolled material in this specification refers to a copper alloy plate material after the cold-rolling process is completed (after a predetermined number of cold-rolling and annealing processes). When the cold rolling process is the final process of the copper alloy material manufacturing process, that is, when the second heat treatment process described later is not performed, the cold rolled material becomes the finally formed copper alloy material.

  The annealing performed in the cold rolling process is performed at a temperature lower than the temperature at which recrystallization occurs in the material to be rolled. For example, it is preferable to perform annealing at a temperature at which the temperature of the material to be rolled is 300 ° C. or higher and 500 ° C. or lower. For example, the time for annealing (annealing time) is preferably 30 seconds or more and 5 minutes or less. As a result, the workability (ductility) of the cold-rolled material can be improved without causing recrystallization accompanied by a reduction in the strength of the copper alloy material in the material to be rolled (without causing recrystallization of Cu as the parent phase to proceed). Can be recovered. Thus, the strength reduction of the copper alloy material can be suppressed by not causing recrystallization in the material to be rolled.

  The final cold rolling performed in the cold rolling process, that is, the final cold rolling performed after the final annealing is preferably performed at a workability of 60% or more and 80% or less, for example. Thereby, while being able to fully raise the intensity | strength of the copper alloy material finally formed, the fall of the ductility of a copper alloy material can also be suppressed.

  If the degree of work of the final cold rolling is less than 60%, work hardening by cold rolling becomes insufficient, so that the strength of the finally formed copper alloy material may be insufficient. By making the workability of the last cold rolling 60% or more, the material to be rolled can be sufficiently work-hardened by cold rolling, and the strength of the copper alloy material can be sufficiently increased.

  However, when the workability of the last cold rolling exceeds 80%, the strain accumulated in the material to be rolled (cold rolled material) may be excessive. For this reason, the conductivity of the copper alloy material finally formed may be reduced, or the ductility may be reduced and the copper alloy material may be broken at a slight elongation. By making the workability of the last cold rolling 80% or less, the distortion accumulated in the material to be rolled can be reduced, and as a result, the decrease in conductivity and ductility of the copper alloy material can be suppressed.

(Second heat treatment step)
After the cold rolling step is completed, a heat treatment (final heat treatment) for holding the cold rolled material at a temperature of 350 ° C. to 450 ° C., for example, for 10 seconds to 5 minutes may be further performed. By performing the final heat treatment under such conditions, the conductivity and ductility of the heat-treated material can be further recovered while suppressing a decrease in the strength of the heat-treated material. As a result, it is possible to further improve the conductivity of the copper alloy material and further improve the ductility (elongation) of the copper alloy material while maintaining the strength of the finally formed copper alloy material at a predetermined strength.

  When the temperature of the material to be heat-treated in the final heat treatment is less than 350 ° C., or when the heating time (heat holding time) is less than 10 seconds, the conductivity and ductility of the material to be heat-treated may be insufficiently recovered. is there. By setting the heating temperature in the final heat treatment to 350 ° C. or higher and the heating time to 10 seconds or longer, the conductivity and ductility of the heat-treated material can be sufficiently recovered. Thereby, while improving the electroconductivity of a copper alloy material, the ductility of a copper alloy material can further be improved.

  However, if the heating temperature exceeds 450 ° C. or the heating time exceeds 5 minutes, recrystallization may occur in the heat-treated material, and as a result, the strength of the copper alloy material may be reduced. By setting the heating temperature to 450 ° C. or less and the holding time to 5 minutes or less, recrystallization can be suppressed from occurring in the heat-treated material. As a result, it is possible to suppress the strength of the copper alloy material from being lowered by the final heat treatment.

  Through the above steps, copper having a conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C. An alloy material can be formed.

(3) Effects According to the Present Embodiment According to the present embodiment, one or a plurality of effects described below are exhibited.

(A) In addition to adding Mg and Sn to the Cu-Fe-Ni-P-based alloy and controlling the composition in the copper alloy, the copper alloy material formed using this copper alloy is a conventional copper alloy. It has higher conductivity, higher strength, and higher stress relaxation resistance than the alloy material. Moreover, in the copper alloy material according to the present embodiment, the stress relaxation resistance can be further improved while improving the conductivity and strength in a balanced manner as compared with the conventional copper alloy material. That is, by including Fe, Ni, P and Mg in an appropriate range in the copper alloy material, the conductivity and strength of the copper alloy material can be improved in a balanced manner. Moreover, by containing a predetermined amount of Sn in the copper alloy material, the stress relaxation resistance and strength of the copper alloy material can be improved as compared with the case where Sn is not contained.

(B) Specifically, 0.2 mass% or more and 0.6 mass% or less of Fe, 0.02 mass% or more and 0.06 mass% or less of Ni, and 0.07 mass% or more and 0.3 mass% or less % P or less, 0.01 mass% or more and 0.2 mass% or less of Mg, and more than 0.05 mass% and 0.2 mass% or less of Sn, with the balance being Cu and inevitable impurities. By controlling the composition of the copper alloy as described above, the copper alloy material formed using this copper alloy can be made into a copper alloy material that satisfies the requirements of higher electrical conductivity, higher strength, and higher stress relaxation resistance than before. can do. For example, the electrical conductivity of the copper alloy material can be 72% IACS or more, the 0.2% proof stress can be 520 MPa or more, and the stress relaxation rate after heating for 1000 hours at 150 ° C. can be 25% or less.

(C) Further, by making the ratio of Fe mass to Fe mass (Fe / Ni) in the copper alloy material 5 or more and 10 or less, the conductivity and strength of the copper alloy material can be improved in a balanced manner. it can.

(D) Moreover, by including 0.001 mass% or more and 0.005 mass% or less Zn in a copper alloy material, solderability can be improved, without reducing the electroconductivity of a copper alloy material. it can.

(E) Moreover, when forming a copper alloy material, after performing a predetermined hot rolling process, by performing the 1st heat treatment process hold | maintained at the temperature of 450 degreeC or more and 550 degrees C or less for 3 hours or more, copper Fe—P compounds and Ni—P compounds can be sufficiently dispersed and precipitated in the alloy material. As a result, the amount of Fe, Ni, and P, which cause a decrease in the conductivity of the copper alloy material as much as possible, can be dissolved in the copper alloy material without producing an Fe—P compound and an Ni—P compound. Can be reduced. As a result, even if Sn that easily lowers conductivity is contained and dissolved, the decrease in conductivity due to other elements dissolved in the copper alloy material can be minimized.

(F) Moreover, a copper alloy is obtained by repeatedly performing a predetermined cold rolling step and a predetermined cold rolling and an annealing performed at a temperature lower than a temperature at which recrystallization occurs in the material to be rolled, a predetermined number of times. The workability (ductility) of the cold-rolled material can be recovered without causing recrystallization accompanied by a reduction in the strength of the material in the material to be rolled. Thus, by preventing recrystallization from occurring in the material to be rolled, a decrease in the strength of the copper alloy material can be reliably suppressed.

(G) Moreover, while performing the last cold rolling performed by a cold rolling process with the workability of 60% or more and 80% or less, this can fully raise the intensity | strength of a copper alloy material, and copper A decrease in ductility of the alloy material can also be suppressed.

(H) In addition, after performing the cold rolling step, the strength of the copper alloy material is increased by performing a final heat treatment for holding the cold rolled material at a temperature of 350 ° C. or higher and 450 ° C. or lower for 10 seconds or longer and 5 minutes or shorter. While maintaining the predetermined strength, the conductivity of the copper alloy material can be further improved, and the ductility (elongation) of the copper alloy material can be further improved.

(I) The copper alloy material according to the present embodiment has high conductivity, high strength, and high stress relaxation resistance. Therefore, the copper alloy material according to the present embodiment includes, for example, a lead frame having a base material (substrate) having a die pad on which a semiconductor element is placed and a lead electrically connected to the semiconductor element. It can be suitably used for a substrate. The base material of the lead frame is formed by punching a copper alloy material. As described above, by using the copper alloy material according to the present embodiment for the base material of the lead frame, it is required for a semiconductor package mounted on the electronic device along with the demand for multi-functionality, size reduction, and weight reduction of the electronic device. To meet the demands for higher density, smaller size, and thinner thickness. In other words, since the copper alloy material has high conductivity, it is possible to ensure sufficient heat dissipation to satisfy demands such as higher density of semiconductor packages (multifunctionalization of electronic devices). Further, since the copper alloy material has high strength, the base material of the lead frame can be thinned, and as a result, it is possible to satisfy the demands such as downsizing and thinning of the semiconductor package. In addition, when the lead frame base material is used for in-vehicle applications, the usage environment may become high in such applications, but the copper alloy material according to the present embodiment has high stress relaxation resistance. ing. For this reason, sufficient reliability can be ensured even when the base material of the lead frame is used in a high temperature environment.

(J) Moreover, the copper alloy material according to the present embodiment includes, for example, a conductor part that is electrically connected to a connector (terminal) on the electronic device side (mating side), and a housing (accommodating part) in which the conductor part is accommodated. ) And the conductor portion of the connector having the above. Thereby, in particular, the connector can be suitably used for the electrical system of the automobile even when the electrical component of the automobile is advanced and the value of the current flowing through the electrical component such as the connector is increased. That is, generation | occurrence | production of a Joule heat can be suppressed because copper alloy material has high electroconductivity. Further, since the copper alloy material has high strength, the spring property required as the specification of the automobile can be satisfied. Further, since the copper alloy material has high stress relaxation resistance, the contact pressure of the connector can be maintained for a long period even when the connector is used in a high temperature environment.

(Other embodiments of the present invention)
As mentioned above, although one Embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the summary, it can change suitably.

  In the above-described embodiment, the molten metal (copper melt, copper alloy melt) is generated using the high-frequency melting furnace, but is not limited thereto. For example, various melting furnaces that can melt a raw material by heating to produce a molten metal can be used.

  In the above-described embodiment, the case where the copper alloy material is used for the lead frame and the connector has been described. However, the present invention is not limited to this.

  Next, examples of the present invention will be described, but the present invention is not limited thereto.

<Production of sample>
(Sample 1)
Using oxygen-free copper as a base material, 0.35 mass% Fe, 0.040 mass% Ni, 0.12 mass% P, 0.10 mass% Mg, and 0.10 mass% Sn It put in the crucible with which the high frequency melting furnace was equipped, and the inside of the crucible was heated in nitrogen atmosphere using the high frequency melting furnace, and the molten metal of the copper alloy was melted. The molten copper alloy melt was poured into a mold having a predetermined shape to cast an ingot having a thickness of 25 mm, a width of 30 mm, and a length of 150 mm (casting process). The obtained ingot was heated to 950 ° C. and hot-rolled to form a hot-rolled material having a thickness of 8 mm (hot-rolling step). The obtained hot-rolled material was heat-treated by heating at 500 ° C. for 8 hours to form a heat-treated material (first heat treatment step). The obtained heat-treated material was cold-rolled, and the thickness of the material to be rolled was 1 mm. And the annealing which heats a to-be-rolled material for 3 minutes at the temperature of 450 degreeC was performed. Next, the cold-rolled material having a work degree of 70% (the last cold rolling) was performed on the annealed rolled material to form a cold-rolled material having a thickness of 0.3 mm (cold rolling). Process). This cold-rolled material was used as the copper alloy material of Sample 1.

(Samples 2-9, 12-23)
In Samples 2 to 9, 12 to 23, the composition of the ingot cast in the casting process, that is, the composition of the copper alloy material was as shown in Table 1 below, so that Fe, Ni, P, Mg, and Sn The addition amount (input amount) was adjusted. Otherwise, a copper alloy material was formed in the same manner as Sample 1 described above. These were designated as Samples 2-9 and 12-23, respectively.

(Samples 10, 11, 24)
In samples 10, 11, and 24, a predetermined amount of Zn was contained in the ingot so that the composition of the ingot cast in the casting process was as shown in Table 1 below. Otherwise, a copper alloy material was formed in the same manner as Sample 1 described above. These were designated as Samples 10, 11, and 24, respectively.

(Samples 25-29, 32-37)
In samples 25-29 and 32-37, the heating conditions (heating temperature, heating time) in the first heat treatment step and the conditions (annealing temperature, annealing time, workability of the last cold rolling) in the cold rolling step are as follows: Table 3 below. Otherwise, a copper alloy material was formed in the same manner as Sample 1 described above. These were designated as Samples 25-29 and 32-37, respectively.

(Samples 30, 31, 38, 39)
Samples 30, 31, 38, and 39 were subjected to a heat treatment (second heat treatment step) in which the cold rolled material was heated at a predetermined temperature for a predetermined time after the cold rolling step. The conditions for the second heat treatment step (heating temperature, heating time) were as shown in Table 3. Otherwise, a copper alloy material was formed in the same manner as Sample 1 described above. These were designated as Samples 30, 31, 38, and 39, respectively.

<Evaluation>
Samples 1 to 39 were evaluated for conductivity, strength, and stress relaxation resistance, respectively. Samples 1, 10, 11, and 24 were also evaluated for solder adhesion (solderability) in addition to the above evaluation.

  The conductivity was evaluated by measuring the conductivity of each sample. The conductivity was measured by a conductivity measuring method based on JIS H0505. The results are shown in Tables 1-3.

  The strength was evaluated by measuring the tensile strength and 0.2% proof stress of each sample. Tensile strength and 0.2% proof stress were measured by a tensile test method based on JIS Z2241. The results are shown in Tables 1 and 3.

  Evaluation of stress relaxation resistance was performed by measuring the stress relaxation rate of each sample. The stress relaxation rate (stress relaxation test) was measured as follows by a method based on the Japan Electronic Materials Association Standard EMA-1011 and the Japan Copper and Brass Association Technical Standard JCBA-T309. First, each sample is put in a cantilever state, and bending (bending stress) is applied so that the initial maximum surface stress is 80% of the 0.2% proof stress. The amount of deflection) was measured. And each sample was heated to 150 degreeC in the state which applied the predetermined bending stress, and was hold | maintained for 1000 hours. After 1000 hours, the bending stress was unloaded and the amount of deflection caused by the permanent deformation was measured. Then, the ratio of the amount of bending due to permanent deformation after heating to the amount of bending of the initially loaded bending ((the amount of bending due to permanent deformation / the initial amount of bending) × 100) is calculated, and this is calculated as the stress relaxation rate (150 ° C. The stress relaxation rate after heating for 1000 hours under the conditions). The calculation results of the stress relaxation rate are shown in Tables 1 and 3.

  Evaluation of solder adhesiveness was performed by performing the following solder heat-resistant peeling test with respect to each sample. First, a test piece having a width of 10 mm and a length of 30 mm was taken from each sample having a thickness of 0.3 mm. Next, each test piece was immersed in lead-free solder (Sn-3 mass% Ag-0.5 mass% Cu) melted and held at 260 ° C. to form a solder layer on the surface of the test piece. This test piece was heated to 180 ° C. and held for 100 hours. Next, the test piece was bent and bent back by 180 °. And about the bending back part, it was evaluated whether the solder layer was peeling. The results are shown in Table 2.

  In addition, the remainder other than the elements which comprise each copper alloy material (ingot) of Table 1 consists of Cu and an unavoidable impurity.

<Evaluation results>
As shown in Table 1, from Samples 1 to 9, 0.2 mass% to 0.6 mass% Fe, 0.02 mass% to 0.06 mass% Ni, and 0.07 mass% It contains not less than 0.3% by mass of P, 0.01% by mass to 0.2% by mass of Mg, and more than 0.05% by mass and not more than 0.2% by mass of Sn, with the balance being Cu. It was also confirmed that the copper alloy material made of inevitable impurities has high conductivity, high strength, and high stress relaxation resistance. That is, the copper alloy materials of Samples 1 to 9 have a conductivity of 72% IACS or more, a tensile strength of 560 MPa or more, a 0.2% proof stress of 520 MPa or more, and 1000 hours at 150 ° C. It was confirmed that the stress relaxation rate after heating was 25% or less. Thus, it was confirmed that the copper alloy materials of Samples 1 to 9 can improve the conductivity, strength, and stress relaxation resistance in a balanced manner as compared with the conventional copper alloy materials.

  In Table 1, from the comparison of Samples 1-9 and Samples 12-13, if the Fe content is less than 0.2% by mass or the Ni content is less than 0.02% by mass, It was confirmed that the 0.2% proof stress may be less than 520 MPa. This is because the Fe and Ni contents are small, so the amount of Fe-P compound and Ni-P compound precipitated in the copper alloy material is reduced. As a result, the strength is improved by the Fe-P compound and Ni-P compound. Since the effect cannot be obtained, it is considered that the strength of the copper alloy material is insufficient.

  In Table 1, it was confirmed from a comparison between Samples 1 to 9 and Sample 16 that the 0.2% proof stress might be less than 520 MPa when the P content was less than 0.07% by mass. This is because even when the content of P is small, the amount of Fe—P compound and Ni—P compound precipitated in the copper alloy material is reduced as in the case where the content of Fe and Ni is small. It is considered that the strength of the alloy material is insufficient.

  In Table 1, from comparison between Samples 1-9 and Samples 14-15, if the Fe content exceeds 0.6 mass% or the Ni content exceeds 0.06 mass%, It was confirmed that the rate could be less than 72% IACS. Further, from comparison between Samples 1 to 9 and Sample 17, it was confirmed that when the P content exceeds 0.3% by mass, the conductivity may be less than 72% IACS. These are thought to be due to a decrease in the conductivity of the copper alloy material because the amount of Fe, Ni, and P dissolved in the copper alloy material increased.

  In Table 1, it was confirmed from comparison between Samples 1 to 9 and Sample 18 that the 0.2% proof stress may be less than 520 MPa when the Mg content is less than 0.01% by mass. . This is considered to be because the strength improvement effect by containing Mg was not sufficiently obtained.

  In Table 1, from comparison between Samples 1 to 9 and Sample 19, Mg is a component that is relatively difficult to lower the electrical conductivity. However, if the Mg content increases too much, the electrical conductivity is increased by Mg. It was confirmed that it may decrease. That is, it was confirmed that when the Mg content exceeds 0.2% by mass, the conductivity may be less than 72% IACS.

  In Table 1, from comparison between Samples 1 to 9 and Sample 20, when the Sn content is 0.05% by mass or less, 0.2% proof stress may be less than 520 MPa, and stress relaxation It was confirmed that the rate might exceed 25%. This is presumably because the stress relaxation resistance and strength improvement effect due to the addition of Sn could not be sufficiently obtained.

  In Table 1, it was confirmed from a comparison between Samples 1 to 9 and Sample 21 that the conductivity might be less than 72% IACS when the Sn content exceeds 0.2 mass%. This is presumably because the conductivity of the copper alloy material was lowered because the amount of Sn dissolved in the copper alloy material increased.

  In Table 1, from comparison between Samples 1 to 9 and Sample 22, even if the content of Fe, Ni, P, Mg, Sn is within a predetermined range, Fe / Ni is less than 5, It was confirmed that the conductivity may be less than 72% IACS.

  Also, in Table 1, from comparison between Samples 1-9 and Sample 23, even if the content of Fe, Ni, P, Mg, Sn is within a predetermined range, Fe / Ni exceeds 10 It was confirmed that the 0.2% proof stress may be less than 520 MPa.

  In Table 2, it was confirmed from the comparison between Sample 1 and Samples 10 and 11 that the inclusion of a predetermined amount of Zn can suppress the peeling of the solder layer and improve the solder adhesion. In addition, it was confirmed that even in the samples 10 and 11 containing a predetermined amount of Zn, the conductivity could be 72% IACS or more. That is, it was confirmed that if the Zn content is a predetermined amount, the influence of Zn on the conductivity is small.

  In Tables 1 and 2, from the comparison between Samples 10 to 11 and Sample 24, when the Zn content exceeds 0.005% by mass, the evaluation of the solder adhesion is good, that is, the peeling of the solder layer Although it was not observed, it was confirmed that the conductivity might be less than 72% IACS.

  In Table 3, from samples 1, 25 to 29, in the first heat treatment step, heat treatment is performed at 450 ° C. or higher and 550 ° C. or lower for 3 hours or more. In the cold rolling step, cold rolling and recrystallization are performed. In addition to performing annealing at a temperature lower than the temperature at which heat treatment occurs, and performing the final cold rolling at a workability of 60% or more and 80% or less, high conductivity, high strength, and high stress relaxation resistance are achieved. It has been confirmed that the copper alloy material can be formed. That is, in Samples 1, 25 to 29, the conductivity is 72% IACS or more, the 0.2% proof stress is 520 MPa or more, and the stress relaxation rate after heating for 1000 hours at 150 ° C. is 25% or less. It was confirmed that As described above, it was confirmed that the samples 1, 25 to 29 can improve the conductivity, strength, and stress relaxation resistance in a balanced manner as compared with the conventional copper alloy material.

  From a comparison between Samples 1 and 26 and Samples 30 and 31, a heat treatment (second heat treatment step) is performed by heating at a temperature of 350 ° C. to 450 ° C. for 10 seconds to 5 minutes after the cold rolling step. Thus, it was confirmed that the stress relaxation resistance and conductivity can be further improved. Note that it was confirmed that the 0.2% proof stress can be maintained at 520 MPa or more although the strength slightly decreases by performing the second heat treatment step.

  In Table 3, from the comparison between Samples 1, 25 to 27 and Samples 32 and 33, the heat treatment temperature (heating temperature) in the first heat treatment step is less than 450 ° C., or the heat treatment in the first heat treatment step. It was confirmed that the electrical conductivity may be less than 72% IACS when the time (heating time) is less than 3 hours. These are considered to be because the Fe—P compound and Ni—P compound could not be sufficiently dispersed and precipitated by heat treatment, and as a result, the amount of Fe, Ni, and P dissolved in the heat treatment material increased.

  In Table 3, from comparison between Samples 1, 25 to 27 and Sample 34, when the heating temperature in the first heat treatment step exceeds 550 ° C., the conductivity becomes less than 72% IACS and 0.2% It was confirmed that the proof stress might be less than 520 MPa. This causes a phenomenon in which the Fe-P compound and Ni-P compound that have been dispersed and precipitated again form a solid solution. As a result, the amount of Fe, Ni, and P dissolved in the heat treatment material increases, and the parent phase Cu This is thought to be because the strength of the heat-treated material greatly decreased due to the progress of recrystallization.

  In Table 3, when the annealing in the cold rolling process is performed at 530 ° C., which is the temperature at which recrystallization proceeds, from the comparison between Samples 1, 25-29 and Sample 35, the 0.2% yield strength is less than 520 MPa. Confirmed that it may become. This is thought to be because the strength of the copper alloy material finally formed was lowered because the strength was lowered because recrystallization occurred in Cu as a parent phase by annealing.

  In Table 3, from comparison between Samples 1, 28, 29 and Sample 36, 0.2% proof stress is less than 520 MPa when the workability of the last cold rolling performed in the cold rolling process is less than 60%. Confirmed that it may become. This is probably because the work hardening by the final cold rolling is insufficient, so that the strength of the copper alloy material could not be sufficiently improved.

  In Table 3, from the comparison of Samples 1, 28, 19 and Sample 37, when the workability of the last cold rolling performed in the cold rolling process exceeds 80%, the conductivity becomes less than 72% IACS. It was confirmed that the stress relaxation rate may exceed 25%. This is considered because excessive strain was accumulated in the material to be rolled by cold rolling.

  In Table 3, when the temperature of the heat treatment performed in the second heat treatment step exceeds 450 ° C. or the time of the heat treatment exceeds 5 minutes from the comparison between the samples 30 and 31 and the samples 38 and 39, 0.2 It was confirmed that the% proof stress may be less than 520 MPa.

<Preferred embodiment>
Hereinafter, preferred embodiments of the present invention will be additionally described.

[Appendix 1]
According to one aspect of the invention,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
There is provided a copper alloy material having an electrical conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C.

[Appendix 2]
The copper alloy material of Appendix 1, preferably,
The ratio of the mass of the iron to the mass of the nickel is 5 or more and 10 or less.

[Appendix 3]
The copper alloy material according to appendix 1 or 2, preferably,
It further contains 0.001 mass% or more and 0.005 mass% or less of zinc.

[Appendix 4]
According to another aspect of the invention,
A casting process for casting the ingot;
A hot rolling step of hot rolling the ingot to form a hot rolled material;
A first heat treatment step of performing a heat treatment on the hot rolled material to form a heat treated material;
A cold rolling step of performing cold rolling on the heat treated material to form a cold rolled material, and
In the casting process,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing the magnesium of 01% by mass or more and 0.2% by mass or less, and tin of more than 0.05% by mass and 0.2% by mass or less, and casting the ingot of which the balance is made of copper and inevitable impurities;
In the first heat treatment step,
The hot-rolled material is heat-treated by holding it at a temperature of 450 ° C. or higher and 550 ° C. or lower for 3 hours or more,
In the cold rolling process,
Cold rolling on the heat treatment material and annealing performed at a temperature lower than the temperature at which recrystallization occurs in the material to be rolled are alternately repeated a predetermined number of times,
Copper alloy material that forms a copper alloy material having a conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C. A manufacturing method is provided.

[Appendix 5]
The method for producing a copper alloy material according to appendix 4, preferably,
In the cold rolling step, after the final annealing, the final cold rolling is performed at a workability of 60% or more and 80% or less.

[Appendix 6]
A method for producing a copper alloy material according to appendix 4 or 5,
After the cold rolling step is completed, the method further includes a second heat treatment step for performing a heat treatment for holding the cold rolled material at a temperature of 350 ° C. to 450 ° C. for 10 seconds to 5 minutes.

[Appendix 7]
According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
Provided is a lead frame having a base material having an electrical conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after 1000 hours of heating at 150 ° C. The

[Appendix 8]
According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
Provided is a connector having a conductor portion having an electrical conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C. .

Claims (8)

0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
A copper alloy material having a conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours under the condition of 150 ° C. The copper alloy material according to claim 1, wherein a ratio of the mass of the iron to the mass of the nickel is 5 or more and 10 or less. The copper alloy material according to claim 1 or 2, further comprising 0.001 mass% or more and 0.005 mass% or less of zinc. A casting process for casting the ingot;
A hot rolling step of hot rolling the ingot to form a hot rolled material;
A first heat treatment step of performing a heat treatment on the hot rolled material to form a heat treated material;
A cold rolling step of performing cold rolling on the heat treated material to form a cold rolled material, and
In the casting process,
0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing the magnesium of 01% by mass or more and 0.2% by mass or less, and tin of more than 0.05% by mass and 0.2% by mass or less, and casting the ingot of which the balance is made of copper and inevitable impurities;
In the first heat treatment step,
Heat-treating the hot-rolled material by holding it at a temperature of 450 ° C. or higher and 550 ° C. or lower for 3 hours or more
In the cold rolling process,
Cold rolling on the heat treatment material and annealing performed at a temperature lower than the temperature at which recrystallization occurs in the material to be rolled are alternately repeated a predetermined number of times,
Copper alloy material that forms a copper alloy material having a conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C. Manufacturing method. 5. The method for producing a copper alloy material according to claim 4, wherein in the cold rolling step, after the last annealing, the last cold rolling is performed at a workability of 60% or more and 80% or less. 6. The method according to claim 4, further comprising a second heat treatment step of performing a heat treatment for holding the cold rolled material at a temperature of 350 ° C. or higher and 450 ° C. or lower for 10 seconds or longer and 5 minutes or less after the cold rolling step is completed. The manufacturing method of the copper alloy material as described in 2. 0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
A lead frame having a base material having a conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C. 0.2 mass% or more and 0.6 mass% or less of iron, 0.02 mass% or more and 0.06 mass% or less of nickel, 0.07 mass% or more and 0.3 mass% or less of phosphorus; Containing from 01% by weight to 0.2% by weight of magnesium, and from 0.05% by weight to 0.2% by weight of tin, the balance consisting of copper and inevitable impurities;
A connector having a conductor portion having an electrical conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25% or less after heating for 1000 hours at 150 ° C.