JPH10298679A - High strength and high conductivity copper alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high strength and high conductivity copper alloy by adding a steel with a specified amounts of Fe and Ni and furthermore with P, Co, Sn, Mn, Ag, Cd, Pb, Zn, Be, In, Te, Y, Cr, Ti, Zr, Mg and B. SOLUTION: This copper alloy is the one having a compsn. in which the total content of Fe and Ni is regulated to, by weight, 1 to 4.5%, the content of P is regulated to 0.1 to 0.8%, and the balance subtantial copper, the total content of Fe and Ni is 3 to 10 times the content of P, and also, Fe/Ni=0.8 to 1.2 is satisfied. This copper alloy is moreover incorporated with one or more kinds of elements selected from the ranges of 0.01 to 1% Co, Sn, Mn, Ag, Cd, Pb and Zn, 0.01 to 0.5% Be, In, Te and Y, 0.01 to 0.2% Cr, Ti, Zr and Mg and 0.001 to 0.1% B in the total range of <=3%. The strength of the copper alloy is equal to that of 42 alloys, and its electric conductivity is regulated to >=50% IACS.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength, high-conductivity copper alloy used for lead materials, terminals, connectors and the like of semiconductor devices, and in particular, has a low cost and a strength substantially equal to that of 42 alloy. Meanwhile, the present invention relates to a high-strength, high-conductivity copper alloy having a conductivity of 50% IACS or more.

[0002]

2. Description of the Related Art Conventionally, a lead material of a semiconductor device has been made of a Cu-N alloy called a 42 alloy for iron and a Corson for copper alloy.
i-Si alloy, Cu-Sn alloy or Cu-Cr
A series alloy is used. A copper-based material has a feature of being superior in heat dissipation because it has higher conductivity than an iron-based material. However, a relatively low strength has led to the development of a composition for increasing the strength. This is especially true for LSIs (Large Scale Integrated Circuits) that have recently exceeded 200 pins.
t) As packages have been manufactured, the tendency of thinner lead materials and narrower widths of inner and outer leads has become more pronounced, and the strength of the leads themselves has been emphasized. .

[0003] Recent ICs (Integrated Circuits) and LSs
Naturally, the trend of high integration and high speed of I will increase the heat generation of the semiconductor chip, and at present, one of the issues is the rational heat dissipation of the semiconductor package.
As a heat radiation path of the semiconductor package, in addition to a method of dissipating through an insulating mold and a method of actively attaching a heat sink, a method of dissipating heat to a wiring board through a lead material is also conceivable.

In this case, the high thermal conductivity (which can be replaced by the value of the conductivity) of the material itself of the lead material directly affects the heat dissipation of the semiconductor package. In this regard, the conventional 42 alloy has about 3% IA
It has an extremely low electrical conductivity of CS (International Annealed Copper Standard), which is a major problem in designing semiconductor packages. Therefore, MOS-IC
In a semiconductor package of (Metal Oxide Semiconductor Integrated Circuit), the material is changed from an iron-based material to a copper-based material, and there is a tendency to use a material having higher conductivity. In this case, the characteristics required for the copper-based material include having characteristics as a general lead material and having a strength substantially equal to that of the 42 alloy. From this, at present, mainly Cu-N
An i-Si-based, Cu-Sn-based, or Cu-Cr-based copper alloy is used.

[0005]

However, according to the conventional copper alloy, the electric conductivity of Cu-Ni-Si is 50%.
In the case of Cu-Sn system, Sn is dissolved in Cu to increase the strength, so that the strength is only about 30% IACS. In the case of Cu-Cr, the conductivity is 70% IAC.
Although high conductivity can be achieved as high as S or more, it is difficult to melt and cast because Cr is a material that is difficult to dissolve and that it easily reacts with carbon which is a refractory material because strength is somewhat insufficient. There is a problem of cost increase.

[0006]

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a low cost,
42 while having a strength almost equivalent to that of the alloy No. 42 and a conductivity of 50.
An object of the present invention is to provide a high-strength and high-conductivity copper alloy having a value of not less than% IACS.

[0007]

According to the present invention, in order to achieve the above object, a total of 1 to 4.5% by weight of Fe and Ni is used.
In a copper alloy containing 0.1 to 0.8% by weight of P, the total of the weight percentages of Fe and Ni is 3 to 10% of the weight percentage of P.
The present invention provides a high-strength and high-conductivity copper alloy characterized in that the weight ratio of Fe to Ni is in the range of 0.8 to 1.2. is there.

In order to achieve the above object, the present invention provides a total of 1 to 4.5% by weight of Fe and Ni, and 0.1% by weight of P.
Fe and N in a copper alloy containing
The sum of the weight percentages of i is 3 to 10 times the weight percentage of P, and the ratio of each weight percentage of Fe and Ni is Fe / Ni =
0.8-1.2, Co, Sn, Mn, Ag, Cd, Pb, Zn: 0.01
-1.0% by weight Be, In, Te, Y: 0.01-0.5% by weight Cr, Ti, Zr, Mg: 0.01-0.2% by weight B: 0.001-0.1% by weight % Of at least one element selected from the range of 3% by weight or less.

Further, in order to achieve the above object, the present invention provides a total of 1 to 4.5% by weight of Fe and Ni, and 0.1% by weight of P.
In the alloying element composition range of the copper alloy containing 0.8 to 0.8% by weight and 0.05 to 2% by weight of Zn, the total of the weight percentages of Fe and Ni is 3 to 10 times the weight percentage of P, And Fe and N
i is in the range of Fe / Ni = 0.8 to 1.
The present invention provides a high-strength and high-conductivity copper alloy characterized by being in the range of 2.

As described above, the first feature of the present invention resides in that Fe, Ni, and P are added to copper at a specific composition ratio, and strength and conductivity are adjusted to preferable values. .

Until now, for example, Japanese Patent Application Laid-Open No.
No. 3 discloses that C for lead frames and electronic devices is used.
A u-Ni-Fe-P-based copper alloy has been proposed. However, in these copper alloys, if P is 0.1% or less, the strength and conductivity based on Fe and Ni are not sufficiently improved, and 0.8% or less.
% Or more, the conductivity decreases, and if the compounding ratio of Fe and Ni deviates from 1 to 1, the balance between the strength and the improvement in the conductivity is lost, and furthermore, the solder does not depend on the compounding ratio of Ni, Fe, and P. When the treatment was performed, it was found that the solder weather resistance was not sufficient. Therefore, first, Fe, Ni, and P were added to copper at a specific composition ratio, and the strength and the electrical conductivity were adjusted to preferable values.

First, regarding the composition range of Fe, Ni, and P, when Fe and Ni are each co-added with P, phosphide is formed, and the strength and conductivity of copper are improved. At this time,
If the total of Fe and Ni is 1% or less, this effect is small, and if it is 4.5% or more, the effect is saturated. In order to effectively form a phosphide by heat-treating Fe and Ni in this composition range, 0.1 to 0.8% of P is required.
If it is 0.1% or less, the formation of phosphide becomes insufficient, so
If it is 8% or more, excess P forms a solid solution in copper and lowers the conductivity.

Further, in the above composition range, the ratio of the total amount of Fe and Ni to the amount of P has an optimum range,
It is necessary that the sum of the weight percentages of Fe and Ni is in the range of 3 to 10 times the weight percentage of P. If this is 3 times or less, P becomes excessive, and if it is 10 times or more, Fe and Ni become excessive,
Each results in a loss of conductivity. Further, if the ratio is in the range of 4 to 6 times, more preferable characteristics can be expected.

Next, there is an optimum range for the ratio between the amount of Fe and the amount of Ni. Fe and Ni are added with the expectation of the same effect on strength and electrical conductivity. However, when Fe is added, the effect on strength improvement is small, but one with higher electrical conductivity is easily obtained. On the other hand, Ni is highly effective in improving strength, but it is difficult to obtain a material having higher conductivity than Fe. Therefore, when designing a material that is harmonized in both strength and electrical conductivity as a lead material for semiconductor equipment,
It is necessary to set the mixing ratio of Fe and Ni to 1 to 1 in a range of 1 to 4.5% in total. In actual melting and casting in mass production, it is almost impossible to make the ratio completely one-to-one. The mixing ratio was set. If the ratio is 0.8 or less, Ni becomes excessive and the conductivity becomes insufficient. If the ratio is 1.2 or more, Fe becomes excessive and the strength becomes insufficient and a harmonized material cannot be obtained.

The second feature of the present invention is that, in addition to the above elements, Co, Sn, Mn, Ag, Cd, Pb, Zn,
The point is that at least one element selected from Be, In, Te, Y, Cr, Ti, Zr, Mg, and B is added.

Of these elements, Mn, Ag, Cd,
Zn and Mg have deoxidizing and desulfurizing effects, and have a high effect of stabilizing the content of P, which is easily linked to oxygen, and an effect of improving hot workability. In addition, Co, Sn, Y, Cr, Ti, and Zr have an effect of making crystal grains fine and improving ductility, and have a high effect of improving strength by solution hardening and precipitation hardening. Further, Pb, Be, In, Te, and B have a high effect of improving the free-cutting property, and improve the press workability at the time of forming the lead material. Although these elements are effective even if added alone,
A more effective effect can be expected by adding two or more kinds in combination according to the function.

However, there is a problem that when these additional elements are added excessively, the conductivity is deteriorated. In addition, if the amount of the hardly soluble material such as Cr and Ti is large, casting becomes difficult. Therefore, the addition amount per element is 0.01 to 1.0% by weight for Co, Sn, Mn, Ag, Cd, Pb and Zn, and 0.01 to 0% for Be, In, Te and Y. 0.5% by weight, Cr, Ti, Zr,
Mg is 0.01 to 0.2% by weight, B is 0.001 to 0.1% by weight, and when two or more elements are added, the total amount is 3% by weight or less. The range of the amount to be added. If the amount is less than this range, it is difficult to expect the effect of adding each element, and if the amount exceeds this range, adverse effects such as deterioration in conductivity, ductility, solderability and plating property are likely to occur. Become.

Further, a third feature of the present invention is that Cu—Ni
Another feature of the present invention is that Zn is added to an Fe-P-based copper alloy at a specific composition ratio to improve solder weather resistance.

Zn is, for example, an element that prevents solder from peeling off in a process in which a lead material of a semiconductor device is soldered to a substrate and undergoes a chemical change at a certain temperature, that is, an element that improves so-called solder weather resistance. It is. Therefore, Z
n is set to 0.05% or more as a minimum addition amount that exerts an effect, and is added in a maximum range of 2% to adversely affect conductivity.

Since each of the above-mentioned additional elements is not an active element and can be easily dissolved and cast, it can be supplied at low cost.

[0021]

【Example】

[Example 1] Pure copper, pure iron, pure nickel, a copper-phosphorus alloy and each of the subcomponent elements were prepared as melting raw materials to prepare samples, and these samples were mixed with charcoal in a high-frequency melting furnace in a predetermined mixing ratio. It was melted and cast to become a component. Table 1 shows the composition of the sample.

[Table 1]

Next, the ingot was hot-rolled to a thickness of 2 mm, oxides on the surface were removed, and cold-rolled to 0.7 mm. Here, a solution treatment of heating at 900 ° C. for 30 minutes and cooling with water was performed. Subsequently, aging treatment was performed at 500 ° C. for 1 hour, cold-rolled again to 0.5 mm, and subjected to a performance test. Table 2 shows the results of the performance test.

[Table 2]

As is clear from Table 2, the copper alloy (No. 1 to No. 13) of the present invention has a conductivity of 50% IACS.
From the above, it can be seen that a well-balanced hardness of 150 Hv or more was obtained. On the other hand, the comparative alloy (No. 1)
4-No. Looking at 23), it was found that N with a small Fe / Ni ratio
o. No. 14 lacks conductivity, and conversely, No. 14 has a large Fe / Ni ratio. 17, No. In 19, the hardness is insufficient.
In the (Fe + Ni) / P ratio, this is small. 15 and No. 18, and conversely, large No. 20 has an extremely low conductivity. Further, when the content of Fe + Ni was as high as 5.0 wt% In No. 16, good characteristics were not obtained even when the ratio of Fe + Ni to P was set to an appropriate value. No. 21-N
o. In No. 23, the amount of the subcomponent is excessive, but the conductivity is low in each case.

Example 2 Pure copper, pure iron, pure nickel, and a copper-phosphorus alloy were prepared as melting raw materials to prepare samples, and these samples were coated with charcoal in a high-frequency melting furnace and mixed with predetermined components. It was melted and cast as it was. Table 3 shows the composition of the sample.

[Table 3]

Next, the ingot was hot-rolled to a thickness of 2 mm, oxides on the surface were removed, and cold-rolled to 0.7 mm. Here, a solution treatment of heating at 900 ° C. for 30 minutes and cooling with water was performed. Subsequently, aging treatment was performed at 500 ° C. for 1 hour, cold-rolled again to 0.5 mm, and subjected to a performance test. Table 4 shows the results of the performance test.

[Table 4]

As apparent from Table 4, the copper alloy (No. 31 to No. 33) of the present invention has a conductivity of 50% IAC.
It can be seen that a balanced performance of S or more and hardness of 150 Hv or more was obtained. On the other hand, the comparative alloy (No.
34-No. Looking at 41), it was found that N with a small Fe / Ni ratio
o. No. 34, the conductivity was insufficient, and conversely, No. 34 having a large Fe / Ni ratio. 39, no. 41 has insufficient hardness.
In the (Fe + Ni) / P ratio, this is small. No. 35 or No. No. 38, and conversely, a large No. 40 has an extremely low conductivity. Further, when the content of Fe + Ni was as high as 5.0 wt% In No. 36, good characteristics were not obtained even when the ratio of Fe + Ni / P was set to an appropriate value. At 38, the conductivity is low.

Although the aging treatment is carried out immediately after the solution treatment in the manufacturing steps of the above-mentioned first and second embodiments, cold rolling may be performed between the two steps.
Two-stage aging treatment may be performed with cold rolling interposed.

[0028]

As described above, according to the high-strength and highly-conductive copper alloy of the present invention, the total amount of Fe and Ni is 1 to 4.5.
% Of P and 0.1 to 0.8% by weight of P, the sum of Fe and Ni by weight is 3% of P
10 to 10 times, and the ratio of each weight% of Fe and Ni is in the range of Fe / Ni = 0.8 to 1.2, so that it is low cost and has almost the same strength as 42 alloy. In addition, a high-strength and high-conductivity copper alloy having a conductivity of 50% IACS or more can be provided. Therefore, it can be used as a lead material for a semiconductor device as an alternative alloy to the 42 alloy. As a result, it is possible to greatly contribute to high speed and high integration of ICs and LSIs.

Claims (3)

[Claims] 1. A total of 1 to 4.5% by weight of Fe and Ni,
In a copper alloy containing 0.1 to 0.8% by weight, the total of the weight percentages of Fe and Ni is 3 to 10 times the weight percentage of P, and the total weight of Fe and Ni is The ratio is Fe
/Ni=0.8-1.2, high strength and high conductivity copper alloy. 2. A total of 1 to 4.5% by weight of Fe and Ni,
In a copper alloy containing 0.1 to 0.8% by weight, the total of the weight percentages of Fe and Ni is 3 to 10 times the weight percentage of P, and the total weight of Fe and Ni is The ratio is Fe
/Ni=0.8-1.2, Co, Sn, Mn, Ag, Cd, Pb, Zn: 0.01
-1.0% by weight Be, In, Te, Y: 0.01-0.5% by weight Cr, Ti, Zr, Mg: 0.01-0.2% by weight B: 0.001-0.1% by weight % Of at least one element selected from the range of 3% by weight or less. 3. A total of 1 to 4.5% by weight of Fe and Ni,
0.1 to 0.8% by weight and 0.05 to 2% by weight of Zn in the alloy element composition range of the copper alloy, and the sum of the weight percentages of Fe and Ni is 3 to 10% by weight of P. Double, and
The ratio of each weight% of Fe and Ni is Fe / Ni = 0.
A high-strength and high-conductivity copper alloy characterized by being in the range of 8 to 1.2.