JPS59157247A - Copper alloy for lead frame - Google Patents

Abstract

PURPOSE:To obtain a Cu alloy for a lead frame for IC with superior workability in manufacture as well as strength, electric conductivity, heat resistance and assembling workability which are comparable to those of phosphor bronze by adding specified amounts of Zn and Zr to Cu. CONSTITUTION:This Cu alloy for a lead frame for IC consists of, by weight, 5.0-20.0% Zn, 0.05-0.5% Zr and the balance Cu. The alloy may further contain about 0.05-0.5% rare earth element and/or about 0.03-0.20% P. The alloy is melted by high-frequency heating in the air, and it is hot-rolled to a plate of about 7mm. thickness at about 800-850 deg.C. After cleaning the surface by pickling, the plate is repeatedly subjected to cold rolling and annealing to obtain a thin plate of about 0.25mm. thickness. About 85% high draft can be attained in the cold rolling stages except the final finish rolling stage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copper-based alloy, particularly a good high-strength type copper alloy, used in a lead frame for C.

Various types of paulownia wood are used for IC frames depending on the model, but phosphor bronze is often used when strength and conductivity are required. However, phosphor bronze has poor workability during production, and requires a large amount of processing from ingot production to finished thin-walled strips, which results in an increase in costs. From this point of view, there is a desire for a copper-based alloy that has excellent manufacturing processability and can be used as a substitute for phosphor bronze.

An object of the present invention is to provide a copper base metal for an IC lead frame that has excellent manufacturing processability and has strength, conductivity, heat resistance, and assembly processability comparable to that of phosphor bronze.

That is, the present invention is a copper base metal for a lead frame characterized by containing 5.0 to 20.0% by weight of zinc, 0.05 to 0.5% by weight of zirconium, and the remainder substantially consisting of steel.

The copper-based alloy of the present invention further contains a rare earth element of 0.05 to 0.
It can contain 5% by weight and/or 0.03 to 0.20% by weight of phosphorus.

The copper-based alloy of the present invention will be explained below.

The copper-based alloy of the present invention has a composition as described above.

If the amount of zinc is less than 5.0%, the strength will be insufficient for practical use, and the
．． If the coefficient is 0 or higher, manufacturing processability will decrease. When the amount of zirconium is less than 0.05%, its contribution to improving heat resistance is insufficient, and when it is more than 0.5%, castability deteriorates. The copper-based alloy of the present invention (d) may contain a rare earth element and/or phosphorus, but when it contains these, the amount of the rare earth element is 0.
If the amount of phosphorus is less than 0.05%, there will be insufficient contribution to improving the manufacturing processability (rolling force control property), if it is more than 0.5%, the castability will decrease, and if the amount of phosphorus is less than 0.03%, there will be insufficient contribution to improving the castability. is insufficient and becomes 0
．． If it exceeds 20%, manufacturing processability (rolling processability) decreases.

Although the copper-based alloy of the present invention has the above-mentioned composition as its main component, it has the same performance even if it contains small amounts of elements such as Fc, N, co, Mn, and Si. There is no problem even if you have a 1.

Next, the alloy of the present invention as shown in Table 1 was used as a sample, and after high-frequency atmospheric melting M, hot rolling was performed at 800 to 850°C, and 7 n+
A plate of II+ thickness was used. Which hot-rolled plate is subjected to pickling treatment for surface cleaning, and then subjected to repeated cold rolling and annealing to produce a plate with a thickness of 0.25m+++. With this method, the workability during annealing was able to be maintained at a high level of about 85%, except for the final finish rolling. In this way, the copper-based alloy of the present invention
Both castability and rolling workability were good, and excellent manufacturing processability could be ensured.

Table 1 Next, a comparison alloy containing the same components as the present invention alloy shown in Table 1 but having a composition other than the present invention, and a conventional example of phosphor bronze (Sn: 4.2%, P O ,04%.

The same tests as above were conducted on the remaining Cu alloy, and the various performances thereof were investigated along with the alloy of the present invention. The results are shown in Table 2.

From the above results, the alloy of the present invention is slightly inferior in repeated bending properties compared to phosphor bronze, which has been widely used in the past, but has approximately the same or superior performance in terms of tensile strength and electrical conductivity, especially at softening temperature. shows a significantly high value for
It can be seen that it has excellent heat resistance. In addition, although the comparison base metals show values comparable to the inventive alloys in terms of usability, many of them have yellow 11 points in manufacturing processability such as castability or rollability. If manufactured in
The production cost would increase significantly, making it impractical from an economic point of view. Products that are easy to manufacture and process, such as Fuka 9, have a problem of extremely poor usability. Among the comparison alloys, those with fragrances 13 and 15 show good performance in both usability and manufacturing processability, which is similar to that of the invention alloy, but the effect of the addition of RE, ]' It is not clear because the amount is small.

The copper-based alloy of the present invention has the following effects.

1) It has superior heat resistance and electrical conductivity compared to phosphor bronze, which is a typical conventional high-strength lead frame alloy.

2) Similarly, compared to phosphor bronze, it generally has better machinability and is cheaper.

Claims (3)

[Claims] (1) A copper base metal for a lead frame, comprising 5.0 to 20.0% by weight of zinc, 0.05 to 0.5% by weight of zirconium, and the remainder substantially copper. (2) The copper base metal for a lead frame according to claim (1), which contains 0.05 to 0.5% by weight of a rare earth element. (3) Special S' containing o, o3 to 0,20% by weight of phosphorus
Copper-based alloy for lead frames according to Scope (1) or (2) of Claim F.