JP6734130B2 - Copper alloy material, manufacturing method of copper alloy material, lead frame and connector - Google Patents

Description

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

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

JP, 2000-017355, A JP 2012-1781 A JP, 2016-011437, A JP, 2016-14165, A

However, even with the above-mentioned 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. There is.

An object of the present invention is to provide a technique for further improving the conductivity, strength and stress relaxation resistance of a copper alloy material.

According to one aspect of the invention,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Containing from 01% by mass to 0.2% by mass of magnesium and from 0.05% by mass to 0.2% by mass of tin, and the balance consisting of copper and unavoidable impurities;
Provided is a copper alloy material having an electric 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 an ingot,
A hot rolling step of forming a hot rolled material by hot rolling the ingot,
A first heat treatment step of performing heat treatment on the hot rolled material to form a heat treated material;
A cold rolling step of forming a cold rolled material by cold rolling the heat treated material,
In the casting process,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and 0.1 mass% or more and 0.2 mass% or less of magnesium, and 0.05 mass% or more and 0.2 mass% or less of tin is contained, and the balance is cast and the ingot composed of copper and unavoidable impurities is cast,
In the first heat treatment step,
The hot rolled material is held at a temperature of 450° C. or higher and 550° C. or lower for 3 hours or more to perform heat treatment,
In the cold rolling step,
Cold rolling for the heat treated 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,
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 method of manufacturing the same is provided.

According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Contains from 01% by mass to 0.2% by mass of magnesium, from 0.05% to 0.2% by mass of tin, and from 0.001% by mass to 0.005% by mass of zinc. , The balance consists of copper and unavoidable impurities,
Provided is a lead frame having a base material having an electric 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. It

According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Contains from 01% by mass to 0.2% by mass of magnesium, from 0.05% to 0.2% by mass of tin, and from 0.001% by mass to 0.005% by mass of zinc. , The balance consists of copper and unavoidable impurities,
Provided is a connector having a conductor having an electric 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 the present invention, it is possible to provide a technique for further improving the conductivity, strength, and stress relaxation resistance of a copper alloy material.

<One Embodiment of the Present Invention>
(1) Configuration of Copper Alloy Material The configuration of the copper alloy material according to one embodiment of the present invention will be described.

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), and the balance is Cu and inevitable impurities. There is. The copper alloy material according to the present embodiment has an electric conductivity of 72% IACS or more, a 0.2% proof stress of 520 MPa or more, and a stress relaxation rate of 25 after heating for 1000 hours at 150° C. % Or less.

Oxygen-free copper (OFC) or the like is preferably used as Cu that is the base material of the copper alloy material (which is the 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. Precipitation of P compounds such as Fe-P compounds and Ni-P compounds in the copper alloy material can improve the strength of the copper alloy material due to 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 amounts 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 solid-dissolved in the copper alloy material increase without producing Fe—P compounds or Ni—P compounds. Therefore, the conductivity of the copper alloy material may decrease. As described above, 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 the present embodiment, in order to suppress the decrease in conductivity while maintaining a predetermined strength and improve the strength and the conductivity in a well-balanced manner, the effect on the conductivity is larger than that of Fe, that is, the conductivity is larger than that of Fe. The content of Ni, which easily deteriorates 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 set 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 will be small, and unless the content of other components such as Ni is increased, the strength of the copper alloy material will be brought to a predetermined strength. There are things you can't do. That is, the strength improving effect of the Fe-P compound may not be obtained.

By setting the Fe content to 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 improving effect of the Fe-P compound can be obtained. it can. For example, the 0.2% proof stress of the copper alloy material can be 520 MPa or more. When the content of Fe is 0.3% by mass or more, the strength improving effect of the Fe-P compound can be reliably obtained.

However, if the content of Fe exceeds 0.6 mass %, the amount of Fe that forms a solid solution in the copper alloy material without forming an Fe—P compound may increase. Therefore, the conductivity of the copper alloy material may decrease.

By setting the content of Fe to 0.6 mass% or less, it is possible to suppress Fe from forming a solid solution in the copper alloy material, and to suppress the decrease in conductivity due to Fe. For example, the electrical conductivity of the copper alloy material can be 72% IACS or more. By setting the content of Fe to 0.5% by mass or less, solid solution of Fe in the copper alloy material can be surely suppressed, and decrease in conductivity due to Fe can be surely suppressed.

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

When the content of Ni is less than 0.02 mass %, the amount of precipitation of Ni—P compound decreases, and unless the content of other components such as Fe is increased, the strength of the copper alloy material becomes a predetermined strength. There are things you can't do. That is, the strength improving effect of the Ni-P compound may not be obtained.

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

However, if the Ni content exceeds 0.06 mass %, the amount of Ni that forms a solid solution in the copper alloy material without forming a Ni—P compound may increase. Therefore, the conductivity of the copper alloy material may decrease.

By setting the Ni content to 0.06 mass% or less, it is possible to suppress the solid solution of Ni in the copper alloy material, and to suppress the decrease in conductivity due to Ni. For example, the electrical conductivity of the copper alloy material can be 72% IACS or more. By setting the Ni content to 0.05% by mass or less, it is possible to reliably suppress solid solution of Ni in the copper alloy material, and it is possible to reliably suppress reduction in conductivity due to Ni.

The content of P in the copper alloy material is, for example, 0.07 mass% or more and 0.3 mass% or less, preferably 0.1 mass% or more and 0.2 mass% or less.

When the content of P is less than 0.07% by mass, the amount of precipitation of Fe-P compound and Ni-P compound decreases, and unless the content of other components such as Mg and Sn is increased, copper alloy material In some cases, the strength of may not be the predetermined strength. That is, the strength improving effect of the Fe-P compound and the Ni-P compound may not be obtained in some cases.

By setting the content of P to 0.07 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 the Fe-P compound and Ni can be deposited. The strength improving effect of the -P compound can be obtained. For example, the 0.2% proof stress of the copper alloy material can be 520 MPa or more. By setting the content of P to be 0.1% by mass or more, the strength improving effect of the Fe-P compound and the Ni-P compound can be reliably obtained.

However, if the content of P exceeds 0.3% by mass, the amount of P that forms a solid solution in the copper alloy material without increasing the formation of Fe—P compound or Ni—P compound may increase. Therefore, the conductivity of the copper alloy material may decrease.

By setting the P content to 0.3% by mass or less, it is possible to prevent P from forming a solid solution in the copper alloy material, and to suppress the decrease in conductivity due to P. For example, the electrical conductivity of the copper alloy material can be 72% IACS or more. By setting the content of P to 0.2% by mass or less, it is possible to reliably suppress the decrease in conductivity due to P.

In the copper alloy material, the contents of Fe and Ni are each within the above-described predetermined ranges, and from the viewpoint of suppressing the occurrence of excess or deficiency of the Ni content (mass) with respect to the Fe content (mass), 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 larger effect on conductivity than Fe, and is more likely to reduce conductivity than Fe. Therefore, if Fe/Ni is less than 5, that is, if 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 a copper alloy material, the balance between strength and conductivity may be lost.

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

However, when Fe/Ni exceeds 10, the content of Ni becomes relatively small, and thus the precipitation amount of the Ni-P compound may decrease. The strength improving effect of the Ni-P compound is greater than the strength improving effect of the Fe-P compound. For this reason, the strength improving effect of the Ni-P compound cannot be sufficiently obtained, and the strength of the copper alloy material may not be set to a predetermined strength. As a result, the balance between strength and conductivity of the copper alloy material may be lost.

By setting Fe/Ni to 10 or less, a certain amount of Ni-P compound can be reliably generated and precipitated in the copper alloy material, and the strength improving effect of 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 well-balanced manner.

As described above, in this embodiment, the content of Ni is relatively smaller than the content of Fe. When the content of Ni 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 precipitation amount of the Ni-P compound is small.

Therefore, the copper alloy material according to the present embodiment further contains a predetermined amount of Mg in addition to Fe, Ni, and P. Mg has the effect of improving the strength of the copper alloy material by forming a solid solution in the copper alloy, that is, by precipitating alone in the parent phase without forming a compound with other elements, and more than copper than Ni. It is a component that does not easily reduce 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 the decrease in the precipitation amount of the Ni-P compound, and by decreasing the Ni content, the copper alloy material 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.

When the content of Mg is less than 0.01% by mass, the amount of Mg dissolved in the copper alloy material is increased by combining Mg with unavoidable impurities such as oxygen (O) and sulfur (S). It may decrease. It should be noted that MgO, MgS, and the like, which are generated by combining Mg with O, S, and the like, do not have the effect of improving the strength of the copper alloy material. As a result, the strength improving effect due to the inclusion of Mg may not be obtained.

By setting the content of Mg to 0.01 mass% or more, a certain amount of Mg can be solid-dissolved in the copper alloy material even if a part of Mg is combined with O, S, or the like. As a result, it is possible to obtain an effect of improving strength by including Mg. For example, the 0.2% proof stress of the copper alloy material can be 520 MPa or more. By setting the content of Mg to 0.03 mass% or more, the strength improving effect due to the addition of Mg can be reliably obtained.

As described above, Mg is a component that is less likely to reduce the conductivity than Ni. However, when the content of Mg exceeds 0.2 mass %, the amount of solid solution Mg in the copper alloy material increases too much, and the conductivity of the copper alloy material may be reduced by Mg.

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

Moreover, as described above, the copper alloy material according to the present embodiment further contains Sn in addition to 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 forming a solid solution in the copper alloy material.

Because, Sn is an element having an atomic radius larger than the atomic radius of Cu serving as the parent phase. An element having an atomic radius larger than the atomic radius of Cu, which is the mother phase, causes lattice distortion in the crystals of the copper alloy material when incorporated into the crystals of the copper alloy material. However, an element having a large atomic radius tends to be associated with vacancies in the crystal of the copper alloy material so as to reduce its lattice distortion. When the vacancies are associated with an element having an atomic radius larger than that of Cu, the volume of the vacancies becomes small.

Further, stress relaxation is a phenomenon in which elastic strain changes into plastic strain over time in a state where a constant strain is applied to a copper alloy material, and the stress decreases. Such stress relaxation proceeds at the atomic level by diffusion of atoms and movement of dislocations. 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 by the Cu atoms jumping and moving (via the holes) through the holes in the crystal. Therefore, for example, even if the copper alloy material is used in a high temperature environment and the Cu atoms try to diffuse, the Cu atoms are reduced by containing Sn in the copper alloy material to reduce the volume of the holes as described above. It becomes difficult to enter the holes. As a result, it becomes difficult for the Cu atoms to jump and move through the holes, and it becomes difficult for the Cu atoms to diffuse. That is, the diffusion of Cu atoms can be suppressed.

Further, an element having a large atomic radius taken into the crystal of the copper alloy material is segregated around 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 the 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 try to move, the dislocations must move while maintaining the state of the Cottrell atmosphere. Therefore, it becomes difficult for dislocations to move, that is, dislocations can be suppressed.

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

In addition to Sn, there are elements having a larger atomic radius than Cu atoms. However, the present inventor has confirmed that Sn has a higher effect of improving the stress relaxation resistance of the copper alloy material than other elements having an atomic radius larger than that of Cu atom.

Further, Sn also exhibits a high strength improving effect by forming a solid solution in the copper alloy. Therefore, by including Sn in the copper alloy material, the strength of the copper alloy material can be further improved. For example, even if the Ni content is reduced as described above, the strength of the copper alloy material can be ensured to be 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.

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

When the Sn content is 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 contents of other elements such as Fe, Ni, and Mg. For example, the 0.2% proof stress of the copper alloy material can be 520 MPa or more. By setting the Sn content to 0.08 mass% or more, the stress relaxation resistance and strength of the copper alloy material can be reliably improved.

Sn is a component that has a high stress relaxation resistance improving effect and a high strength improving effect as described above, but is also a component that easily lowers conductivity. Therefore, if the Sn content exceeds 0.2 mass% and the amount of Sn that forms a solid solution in the copper alloy material increases, the conductivity of the copper alloy material may decrease.

By setting the Sn content to 0.2 mass% or less, it is possible to suppress the 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 lowering the conductivity of the copper alloy material. By setting the Sn content to 0.15 mass% or less, it is possible to reliably suppress the decrease in conductivity due to Sn.

Furthermore, the copper alloy material may contain zinc (Zn). As a result, when the copper alloy material is used, for example, as a base material of a lead frame or a conductor portion of a connector, Zn is solid-dissolved in the copper alloy material, so that the copper alloy material and the solder layer are separated from each other. Can be suppressed. That is, the solderability (solder adhesion) can be improved. As a result, the reliability of soldering can be improved. The reliability of such soldering is one of the important characteristics especially for the lead frame.

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

When the content of Zn is less than 0.001% by mass, the amount of Zn dissolved in the copper alloy material may decrease due to the bonding of Zn with O or S which are inevitable impurities. is there. It should be noted that ZnO, ZnS, etc., which are generated by combining Zn with O, S, etc., do not have the effect of improving solderability. As a result, the effect of improving the solderability by containing Zn may not be obtained.

By setting the content of Zn to be 0.001 mass% or more, a certain amount of Zn can be solid-dissolved in the copper alloy material even if part of Zn is bonded to O, S, or the like. As a result, the effect of improving solderability by containing Zn can be obtained.

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

When the content of Zn is 0.005 mass% or less, the solderability can be improved without lowering the conductivity of the copper alloy material.

(2) Manufacturing Method of Copper Alloy Material Next, a manufacturing method of the copper alloy material according to the present embodiment will be described by exemplifying 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 to generate a molten copper. Fe, Ni, P, Mg and Sn are added to the molten copper to produce a molten copper alloy. At this time, the Fe content is 0.2% by mass or more and 0.6% by mass or less, the Ni content is 0.02% by mass or more and 0.06% by mass or less, and the P content is 0. 07 mass% or more and 0.3 mass% or less, Mg content is 0.01 mass% or more and 0.2 mass% or less, Sn content is more than 0.05 mass% and 0.2 mass% The addition amount (input amount) of Fe, Ni, P, Mg and Sn is adjusted so as to be as follows. Further, it is preferable to further adjust the added amounts of Fe and Ni so that the ratio of the mass of Fe to the mass of Ni (Fe/Ni) is 5 or more and 10 or less. Further, the molten metal of the copper alloy may further contain Zn. In this case, the addition amount of Zn is adjusted so that the Zn content is 0.001 mass% or more and 0.005 mass% or less. Then, the molten metal of this 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 workability (for example, the total workability is 60% or more and 95% or less). , Forming a hot-rolled material having a predetermined thickness. The hot rolled material in the present specification refers to a copper alloy plate material formed by performing a hot rolling step.

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

As described above, the ingot that is the base of the finally formed copper alloy material (hereinafter, also simply referred to as “copper alloy material”) contains Sn that is a component that easily lowers conductivity. .. Therefore, by sufficiently aging the hot-rolled material at an appropriate temperature, the Fe-P compound and the Ni-P compound are sufficiently dispersed and precipitated in the copper alloy material, and the Fe-P compound, The amount of Fe, Ni, and P that forms a solid solution in the copper alloy material is reduced as much as possible, which is a factor that reduces the conductivity in addition to Sn without generating a Ni-P compound. As a result, even when Sn is contained, it is possible to minimize the decrease in conductivity due to the element that forms a solid solution in the copper alloy material. In addition, high conductivity can be maintained even after performing the cold rolling step described below.

In the first heat treatment step, the hot-rolled material was heated at a temperature of, for example, 450° C. or higher and 550° C. or lower, that is, the hot-rolled material was heated to a temperature of, for example, 450° C. or higher and 550° C. or lower. 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 the Ni-P compound can be sufficiently dispersed and deposited to improve the strength of the copper alloy material, and Fe, Ni, and P are prevented from forming a solid solution in the copper alloy material. It is possible to suppress the decrease in conductivity of the copper alloy material.

When the heat treatment temperature (heating temperature) was less than 450° C. or the heat treatment time (heating (holding) time) was less than 3 hours, a predetermined amount of Fe, Ni, P was contained in the copper alloy. Even in such a case, the Fe-P compound and the Ni-P compound may not be sufficiently dispersed and precipitated in the copper alloy material. Therefore, in the copper alloy material, the effect of improving the strength by the Fe-P compound and the Ni-P compound cannot be obtained, and as a result, the strength of the copper alloy material may not be a predetermined strength. Furthermore, since the Fe-P compound and the Ni-P compound cannot be sufficiently dispersed and precipitated, Fe, Ni, which is solid-solved in the copper alloy material without generating the Fe-P compound and the Ni-P compound, The amount of P may increase. As a result, the conductivity of the copper alloy material may decrease.

By setting the heat treatment temperature to 450° C. or higher and the heat treatment time to 3 hours or longer, the Fe—P compound and the Ni—P compound can be sufficiently dispersed and precipitated, and as a result, Fe in the copper alloy material, It is possible to suppress the solid solution of Ni and P. As a result, in the copper alloy material, the strength improving effect of the Fe-P compound and the Ni-P compound can be obtained, the strength of the copper alloy material can be set to a predetermined strength, and the conductivity of the copper alloy material can be improved. The decrease 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, and as a result, Fe, Ni, and P form a solid solution in the copper alloy material. It can be surely suppressed. As a result, in the copper alloy material, it is possible to surely obtain the strength improving effect of the Fe-P compound and the Ni-P compound, and it is possible to surely suppress the decrease in the conductivity of the copper alloy material.

However, when the temperature of the heat treatment exceeds 550° C., a phenomenon in which the dispersed and precipitated Fe—P compound or Ni—P compound again forms a solid solution, and the amount of Fe or Ni remaining in a solid solution state in the heat treated material increases. There is. For this reason, the amounts of Fe, Ni, and P that form a solid solution in the copper alloy material increase, and as a result, the conductivity of the copper alloy material may decrease. If the heat treatment temperature exceeds 550° C., recrystallization of Cu, which is the parent phase, may proceed, and the strength of the heat treated material may decrease.

By setting the temperature of the heat treatment to 550° C. or lower, the above phenomenon can be suppressed. As a result, solid solution of Fe, Ni, and P in the copper alloy material can be suppressed, and as a result, decrease in conductivity of the copper alloy material can be suppressed. Further, it is possible to suppress the progress of recrystallization of Cu that is the mother phase, and it is possible to prevent the strength of the heat-treated material (copper alloy material) from decreasing.

(Cold rolling process)
After the completion of the first heat treatment step, 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 of the heat-treated material and annealing of the material to be rolled are alternately repeated a predetermined number of times. The cold rolling process is preferably finished by cold rolling instead of annealing. The cold rolled material in the present specification refers to a copper alloy sheet material after the cold rolling step is completed (after a predetermined number of times of cold rolling and annealing). When the cold rolling step is the final step of the copper alloy material manufacturing step, that is, when the second heat treatment step described below is not performed, the cold rolled material is the finally formed copper alloy material.

The annealing performed in the cold rolling step 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 such that the temperature of the material to be rolled is 300° C. or higher and 500° C. or lower. Further, 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 of the copper alloy material accompanied by a decrease in strength in the material to be rolled (without promoting recrystallization of Cu, which is the parent phase). Can be recovered. By not causing recrystallization in the material to be rolled in this way, it is possible to suppress a decrease in strength of the copper alloy material.

The final cold rolling performed in the cold rolling step, that is, the final cold rolling performed after the final annealing is preferably performed with a workability of, for example, 60% or more and 80% or less. As a result, the strength of the finally formed copper alloy material can be sufficiently increased, and the reduction in ductility of the copper alloy material can be suppressed.

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

However, if the workability of the final cold rolling exceeds 80%, the strain accumulated in the material to be rolled (cold rolled material) may become excessive. Therefore, the conductivity of the finally formed copper alloy material may decrease, or the ductility may decrease and the copper alloy material may break with a slight elongation. By setting the workability of the final cold rolling to 80% or less, the strain accumulated in the material to be rolled can be reduced, and as a result, the decrease in conductivity and the decrease in ductility of the copper alloy material can be suppressed.

(Second heat treatment step)
After the cold rolling step is finished, a heat treatment (final heat treatment) may be further performed in which the cold rolled material is held at a temperature of, for example, 350° C. or higher and 450° C. or lower for, for example, 10 seconds or more and 5 minutes or less. By performing the final heat treatment under such conditions, it is possible to further recover the conductivity and ductility of the heat treated material while suppressing the decrease in strength of the heat treated material. As a result, the conductivity of the copper alloy material can be further improved and the ductility (elongation) of the copper alloy material can be further improved 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 (heating 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 restored. Thereby, the conductivity of the copper alloy material can be further improved, and the ductility of the copper alloy material can be further 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 decrease. By setting the heating temperature to 450° C. or lower and the holding time to 5 minutes or shorter, it is possible to suppress recrystallization in the material to be heat treated. As a result, it is possible to prevent the strength of the copper alloy material from decreasing due to 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 of this Embodiment According to this embodiment, one or more of the following effects are exhibited.

(A) In a Cu-Fe-Ni-P-based alloy, Mg and Sn are further added, and the composition of the copper alloy is controlled so that the copper alloy material formed using this copper alloy is a conventional copper alloy material. It has higher conductivity, higher strength and higher stress relaxation resistance than the alloy material. Further, the copper alloy material according to the present embodiment can improve the stress relaxation resistance while improving the conductivity and the strength in a well-balanced manner as compared with the conventional copper alloy material. That is, by containing Fe, Ni, P and Mg in an appropriate range in the copper alloy material, it is possible to improve the conductivity and strength of the copper alloy material in a well-balanced manner. Further, 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 more than in 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, 0.01% by mass or more and 0.2% by mass or less Mg, and 0.05% by mass or more and 0.2% by mass or less Sn, with the balance being Cu and inevitable impurities. By controlling the composition of the copper alloy as described above, a copper alloy material formed by using this copper alloy is provided with a copper alloy material satisfying the requirements of higher conductivity, higher strength, and higher stress relaxation resistance than ever 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 setting the ratio of the mass of Fe to the mass of Ni (Fe/Ni) in the copper alloy material to 5 or more and 10 or less, the conductivity and strength of the copper alloy material can be improved in a well-balanced manner. it can.

(D) Further, by containing 0.001% by mass or more and 0.005% by mass or less of Zn in the copper alloy material, the solderability can be improved without lowering the conductivity of the copper alloy material. it can.

(E) Further, in forming the copper alloy material, after performing a predetermined hot rolling step, a first heat treatment step of holding at a temperature of 450° C. or higher and 550° C. or lower for 3 hours or more is performed to obtain copper. The Fe-P compound and the Ni-P compound can be sufficiently dispersed and precipitated in the alloy material. As a result, the amounts of Fe, Ni, and P, which form a solid solution in the copper alloy material and cause a decrease in the conductivity of the copper alloy material, without forming the Fe-P compound and the Ni-P compound are possible. Can be reduced. As a result, even when Sn is contained as a solid solution, which tends to reduce the conductivity, it is possible to minimize the decrease in the conductivity due to the other solid solution in the copper alloy material.

(F) Further, the cold rolling step is performed by alternately repeating 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 by a predetermined number of times, thereby obtaining a copper alloy. The workability (ductility) of the cold-rolled material can be recovered without causing recrystallization in the material to be rolled that causes a reduction in the strength of the material. In this way, by preventing recrystallization from occurring in the rolled material, it is possible to reliably suppress the decrease in strength of the copper alloy material.

(G) Further, the final cold rolling performed in the cold rolling step is performed at a workability of 60% or more and 80% or less, whereby the strength of the copper alloy material can be sufficiently increased and the copper It is also possible to suppress a decrease in ductility of the alloy material.

(H) Further, after performing the cold rolling step, by performing a final heat treatment of holding the cold rolled material at a temperature of 350° C. or higher and 450° C. or lower for 10 seconds or more and 5 minutes or less, the strength of the copper alloy material is improved. It is possible to further improve the electrical conductivity of the copper alloy material and further improve the ductility (elongation) of the copper alloy material while maintaining the predetermined strength.

(I) The copper alloy material according to this embodiment has high conductivity, high strength, and high stress relaxation resistance. Therefore, the copper alloy material according to the present embodiment, for example, in a lead frame having a base material (substrate) having a die pad on which a semiconductor element is mounted and leads electrically connected to the semiconductor element, It can be suitably used as a substrate. The base material of the lead frame is formed by punching a copper alloy material. By using the copper alloy material according to the present embodiment as the base material of the lead frame in this way, along with the demand for multifunctionalization, miniaturization, and weight reduction of electronic devices, there is a demand for semiconductor packages mounted in electronic devices. It is possible to meet the demands for higher density, smaller size and thinner thickness. That is, since the copper alloy material has high conductivity, it is possible to secure sufficient heat dissipation to meet the requirements such as high 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, the demands for downsizing and thinning of the semiconductor package can be satisfied. Further, when the base material of the lead frame is used for in-vehicle applications, the use environment may be high in such applications, but the copper alloy material according to the present embodiment has high stress relaxation resistance. ing. Therefore, sufficient reliability can be ensured even when the base material of the lead frame is used in a high temperature environment.

(J) Further, the copper alloy material according to the present embodiment includes, for example, a conductor portion electrically connected to a connector (terminal) on the electronic device side (counterpart side) and a housing (accommodating portion) in which the conductor portion is accommodated. ), and a conductor part of a connector having As a result, the connector can be preferably used in the electric system of the vehicle, even when the electric component of the vehicle is increased and the value of the current flowing through the electric component such as the connector is increased. That is, since the copper alloy material has high conductivity, generation of Joule heat can be suppressed. In addition, since the copper alloy material has high strength, it is possible to satisfy the spring property required for automobile specifications. Further, since the copper alloy material has high stress relaxation resistance, the contact pressure of the connector can be maintained for a long time even when the connector is used in a high temperature environment.

(Other Embodiments of the Present Invention)
Although one embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment and can be appropriately modified without departing from the scope of the invention.

In the above-described embodiment, the high-frequency melting furnace is used to generate the molten metal (molten copper, molten copper alloy), but the invention is not limited to this. For example, it is possible to use various melting furnaces capable of heating a raw material and melting it to generate a molten metal.

In the above embodiment, the case where the copper alloy material is used for the lead frame and the connector has been described, but 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 are added. It was charged into a crucible provided in the high-frequency melting furnace, and the inside of the crucible was heated in a nitrogen atmosphere using the high-frequency melting furnace to melt the copper alloy. The molten metal of the melted copper alloy 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 step). 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 a temperature of 500° C. for 8 hours to form a heat-treated material (first heat treatment step). The obtained heat-treated material was cold-rolled so that the material to be rolled had a thickness of 1 mm. Then, the material to be rolled was annealed by heating it at a temperature of 450° C. for 3 minutes. Next, the annealed material to be rolled was cold-rolled with a workability of 70% (last cold rolling) to form a cold-rolled material with 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 and 12 to 23, Fe, Ni, P, Mg, and Sn were used so that the composition of the ingot cast in the casting step, that is, the composition of the copper alloy material is as shown in Table 1 below. The addition amount (input amount) was adjusted. Otherwise, a copper alloy material was formed in the same manner as in Sample 1 described above. These were designated as Samples 2 to 9 and 12 to 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. A copper alloy material was formed in the same manner as in Sample 1 above except for the above. These were designated as Samples 10, 11, and 24, respectively.

(Samples 25-29, 32-37)
In Samples 25 to 29 and 32 to 37, the heating conditions (heating temperature, heating time) in the first heat treatment step and the conditions (annealing temperature, annealing time, final cold rolling workability) in the cold rolling step were as follows. As shown in Table 3 of A copper alloy material was formed in the same manner as in Sample 1 above except for the above. These were designated as samples 25 to 29 and 32 to 37, respectively.

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

<Evaluation>
The samples 1 to 39 were evaluated for conductivity, strength, and stress relaxation resistance. In addition to Samples 1, 10, 11, and 24, solder adhesion (solderability) was also evaluated.

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 to 3.

The strength was evaluated by measuring the tensile strength and 0.2% proof stress of each sample. The 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.

The stress relaxation resistance was evaluated by measuring the stress relaxation rate of each sample. The measurement of the stress relaxation rate (stress relaxation test) was carried out by the method according to the Japan Electronic Material Industry Association standard EMAS-1011 and the Japan Copper and Brass Association technical standard JCBA-T309 as follows. First, each sample is placed in a cantilevered 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 bending) was measured. Then, each sample was heated to 150° C. and kept for 1000 hours while a predetermined bending stress was applied. After 1000 hours had passed, the bending stress was removed and the amount of bending due to the permanent deformation that occurred was measured. Then, the ratio of the amount of bending due to permanent deformation after heating and holding to the amount of bending bending initially loaded ((amount of bending due to permanent deformation/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.

The solder adhesion was evaluated by performing the following solder heat resistance peeling test on each sample. First, a test piece having a width of 10 mm and a length of 30 mm was sampled 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) melt-held at 260°C to form a solder layer on the surface of the test piece. The test piece was heated to 180° C. and held for 100 hours. Next, the test piece was bent and bent back by 180°. Then, the bent back portion was evaluated as to whether or not the solder layer was peeled off. The results are shown in Table 2.

The balance other than the elements forming each copper alloy material (ingot) shown in Table 1 is composed of Cu and unavoidable impurities.

<Evaluation result>
As shown in Table 1, from Samples 1 to 9, 0.2% by mass or more and 0.6% by mass or less Fe, 0.02% by mass or more and 0.06% by mass or less Ni, and 0.07% by mass. Not less than 0.3 mass% and not more than 0.01 mass% and not more than 0.2 mass% of Mg, and more than 0.05 mass% and not more than 0.2 mass% Sn, and the balance Cu It was confirmed that the copper alloy material composed of and unavoidable impurities has high conductivity, high strength, and high stress relaxation resistance. That is, the copper alloy materials of Samples 1 to 9 have an electric 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 a temperature of 150° C. for 1000 hours. It was confirmed that the stress relaxation rate after heating was 25% or less. As described above, it was confirmed that the copper alloy materials of Samples 1 to 9 could improve the conductivity, strength, and stress relaxation resistance in a better balance than the conventional copper alloy materials.

In Table 1, from the comparison between Samples 1 to 9 and Samples 12 to 13, it is found that the Fe content is less than 0.2 mass% or the Ni content is less than 0.02 mass%. It was confirmed that the 0.2% proof stress may be less than 520 MPa. This is because the contents of Fe and Ni are small, so the amounts of Fe-P compound and Ni-P compound precipitated in the copper alloy material are small, and 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, from the comparison between Samples 1 to 9 and Sample 16, it was confirmed that the 0.2% proof stress may be less than 520 MPa when the P content was less than 0.07 mass %. This is because even when the P content is small, the Fe-P compound and the Ni-P compound precipitated in the copper alloy material are small as in the case where the Fe and Ni contents are small. It is considered that the strength of the alloy material is insufficient.

In Table 1, from the comparison between Samples 1 to 9 and Samples 14 to 15, if the Fe content exceeds 0.6 mass% or the Ni content exceeds 0.06 mass%, the conductivity It was confirmed that the rate could be less than 72% IACS. In addition, from the comparison between Samples 1 to 9 and Sample 17, it was confirmed that the electrical conductivity may be less than 72% IACS when the P content exceeds 0.3 mass %. It is considered that, since the amounts of Fe, Ni, and P dissolved in the copper alloy material increased, the conductivity of the copper alloy material decreased.

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

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

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

In Table 1, from the comparison between Samples 1 to 9 and Sample 21, it was confirmed that the electrical conductivity may be less than 72% IACS when the Sn content exceeds 0.2 mass %. It is considered that this is because the conductivity of the copper alloy material decreased because the amount of Sn dissolved in the copper alloy material increased.

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

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

In Table 2, from the comparison between Sample 1 and Samples 10 and 11, it was confirmed that by containing a predetermined amount of Zn, peeling of the solder layer can be suppressed and solder adhesion can be improved. It was also confirmed that even the samples 10 and 11 containing a predetermined amount of Zn could have a conductivity of 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 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 could be less than 72% IACS.

In Table 3, from Samples 1, 25 to 29, in the first heat treatment step, heat treatment of heating at a temperature of 450° C. or higher and 550° C. or lower for 3 hours or more is performed, and in the cold rolling step, cold rolling and recrystallization are performed. Annealing at a temperature lower than the temperature at which is generated, and by performing the final cold rolling with a workability of 60% or more and 80% or less, high conductivity, high strength, and high stress relaxation resistance can be obtained. It was confirmed that the copper alloy material having the same could be formed. That is, in Samples 1, 25 to 29, the conductivity was 72% IACS or more, the 0.2% proof stress was 520 MPa or more, and the stress relaxation rate after heating for 1000 hours at 150° C. was 25% or less. I confirmed. Thus, it was confirmed that in Samples 1, 25 to 29, the conductivity, strength, and stress relaxation resistance could be improved in a better balance than the conventional copper alloy material.

From the comparison between Samples 1 and 26 and Samples 30 and 31, heat treatment (second heat treatment step) of heating for 10 seconds or more and 5 minutes or less at a temperature of 350° C. or higher and 450° C. or lower is performed after the cold rolling process. It was confirmed that the stress relaxation resistance and the conductivity can be further improved. It was confirmed that the 0.2% proof stress can be maintained at 520 MPa or more, although the strength is slightly reduced 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 temperature of the heat treatment in the first heat treatment step (heating temperature) is less than 450° C., or the heat treatment in the first heat treatment step It was confirmed that the electric conductivity may be less than 72% IACS if the time (heating time) was less than 3 hours. It is considered that these are because the Fe-P compound and the Ni-P compound could not be sufficiently dispersed and precipitated by the heat treatment, and as a result, the amounts of Fe, Ni, and P which were solid-solved in the heat-treated 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 yield strength could be less than 520 MPa. This is because the Fe-P compound or the Ni-P compound dispersed and precipitated again forms a solid solution, and as a result, the amounts of Fe, Ni, and P that form a solid solution in the heat-treated material increase, and at the same time, the parent phase Cu. It is considered that the strength of the heat-treated material was greatly reduced due to the progress of recrystallization of the.

In Table 3, from comparison between Samples 1, 25 to 29 and Sample 35, when the annealing in the cold rolling step is performed at 530° C. which is the temperature at which recrystallization proceeds, 0.2% proof stress is less than 520 MPa. I have confirmed that it may become. It is considered that this is because the strength was lowered due to the recrystallization of Cu, which is the mother phase, due to the annealing, and thus the strength of the finally formed copper alloy material was lowered.

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

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

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

<Preferred embodiment>
Hereinafter, the 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 iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Containing from 01% by mass to 0.2% by mass of magnesium and from 0.05% by mass to 0.2% by mass of tin, and the balance consisting of copper and unavoidable impurities;
Provided is a copper alloy material having an electric 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 according to 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% by mass or more and 0.005% by mass or less of zinc.

[Appendix 4]
According to another aspect of the invention,
A casting process for casting an ingot,
A hot rolling step of forming a hot rolled material by hot rolling the ingot,
A first heat treatment step of performing heat treatment on the hot rolled material to form a heat treated material;
A cold rolling step of forming a cold rolled material by cold rolling the heat treated material,
In the casting process,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and 0.1 mass% or more and 0.2 mass% or less of magnesium, and 0.05 mass% or more and 0.2 mass% or less of tin is contained, and the balance is cast and the ingot composed of copper and unavoidable impurities is cast,
In the first heat treatment step,
The hot rolled material is held at a temperature of 450° C. or higher and 550° C. or lower for 3 hours or more to perform heat treatment,
In the cold rolling step,
Cold rolling for the heat treated 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,
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 method of manufacturing the same 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 with a workability of 60% or more and 80% or less.

[Appendix 6]
The method for producing a copper alloy material according to Supplementary Note 4 or 5, preferably,
After the completion of the cold rolling step, the method further includes a second heat treatment step of performing 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 more and 5 minutes or less.

[Appendix 7]
According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Containing from 01% by mass to 0.2% by mass of magnesium and from 0.05% by mass to 0.2% by mass of tin, and the balance consisting of copper and unavoidable impurities;
Provided is a lead frame having a base material having an electric 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. It

[Appendix 8]
According to yet another aspect of the invention,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Containing from 01% by mass to 0.2% by mass of magnesium and from 0.05% by mass to 0.2% by mass of tin, and the balance consisting of copper and unavoidable impurities;
Provided is a connector having a conductor having an electric 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 iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Containing from 01% by mass to 0.2% by mass of magnesium and from 0.05% by mass to 0.2% by mass of tin, and the balance consisting of copper and unavoidable impurities;
A copper alloy material having an electric 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. 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 containing 0.001% by mass or more and 0.005% by mass or less of zinc. A casting process for casting an ingot,
A hot rolling step of forming a hot rolled material by hot rolling the ingot,
A first heat treatment step of performing heat treatment on the hot rolled material to form a heat treated material;
A cold rolling step of forming a cold rolled material by cold rolling the heat treated material,
In the casting process,
0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and 0.1 mass% or more and 0.2 mass% or less of magnesium, and 0.05 mass% or more and 0.2 mass% or less of tin is contained, and the balance is cast and the ingot composed of copper and unavoidable impurities is cast,
In the first heat treatment step,
The hot rolled material is held at a temperature of 450° C. or higher and 550° C. or lower for 3 hours or more to perform heat treatment,
In the cold rolling step,
Cold rolling for the heat treated material, and annealing performed at a temperature lower than the temperature at which recrystallization occurs in the material to be rolled, alternately repeated a predetermined number of times,
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. The said cold rolling process is a manufacturing method of the copper alloy material of Claim 4 which performs the last cold rolling with the workability of 60% or more and 80% or less after the last annealing. The method 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 more and 5 minutes or less after the cold rolling step is completed. The method for producing a copper alloy material according to. 0.2 mass% or more and 0.6 mass% or less iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Contains from 01% by mass to 0.2% by mass of magnesium, from 0.05% to 0.2% by mass of tin, and from 0.001% by mass to 0.005% by mass of zinc. , The balance consists of copper and unavoidable impurities,
A lead frame having a base material having an electric 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 iron, 0.02 mass% or more and 0.06 mass% or less nickel, 0.07 mass% or more and 0.3 mass% or less phosphorus, and Contains from 01% by mass to 0.2% by mass of magnesium, from 0.05% to 0.2% by mass of tin, and from 0.001% by mass to 0.005% by mass of zinc. , The balance consists of copper and unavoidable impurities,
A connector having a conductor 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.