JPS62130247A - Copper alloy for electronic appliance - Google Patents

Abstract

PURPOSE:To improve the strength, electric conductivity, heat resistance and bonding characteristics by adding specified amounts of Mg, Cr, etc., to Cu. CONSTITUTION:The composition of an alloy is composed of 0.005-0.8wt% Mg, 0.01-1.0wt% Cr, 0.003-0.5wt% in total of one or more among Ti, Mn, Fe, Co, Ni, Hf, V, Zn, Sn, Ca, B, Y, Si and a rare earth element, and the balance Fe with inevitable impurities. The addition of Mg and Cr improves the strength and heat resistance, and within the restricted ranges, the effect of the 3rd added element is produced. The Cu alloy has superior strength, heat resistance and bonding characteristics, so it is usable as a material for electronic appliances.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention has excellent strength, electrical conductivity, and heat resistance, and has good plating, molding, and bonding properties, and is particularly suitable for use in electronic devices as lead frames for semiconductors. This is related to copper alloys.

(Prior Art) Copper alloys for electronic devices, particularly lead frames for semiconductors, are generally required to have the following characteristics.

(1) Must be a good conductor of electricity and heat.

(2) Good heat resistance.

(3) Good solder plating properties.

(4) Good moldability with resin.

(5) Good hondability with semiconductor elements and wires.

Cu-0 has traditionally been used as a material that satisfies these characteristics.
, 15wt%3n alloy and Cu-0,1wt%Fe-P (
Hereinafter, wt% will be abbreviated as %).

(Problems to be Solved by the Invention) In recent years, with the development of semiconductors and other electronic devices, the required characteristics have become higher, and the development of even better lead frames is strongly desired, especially in the semiconductor industry.

[Means for solving problems]

In view of this, as a result of various studies, the present invention has developed a copper alloy for electronic devices that has excellent strength, heat resistance, and moldability, and has an MCl of 0.005 to 0.8. Cr0.01~1.0
%, and further includes Ti, Mn, and Fe.

Go, Ni, Hf, V, Zn, Sn, Ca, B.

It is characterized in that it contains one or more of Y, Si, and rare earth elements in a total amount of 0.003 to 0.5%, and the remainder consists of CLI and inevitable impurities.

[Effect]

In the present invention, the addition of MQ and Cu is to improve strength and heat resistance, and the Mg content is 0.005 to 0.8%.
, the Cr content was limited to o, oi~1.0% because
If the content of either MCI or Cu is less than the lower limit, the strength and heat resistance will be insufficient, and even if a third element is added, the effect will not be obtained, and if the content of either one exceeds the upper limit. This is because it leads to deterioration of conductivity and workability.

Also, Ti, Mn, Fe, Co, Ni, Hf.

The addition of one or more of V, Zn, 3n, Ca, B, Y, Si, and rare earth elements (hereinafter abbreviated as element X) is to further improve strength and heat resistance. ,
The reason why the content of the X element is limited to 0,003 to 0.5 wt% is that if it is less than the lower limit, a sufficient effect cannot be obtained, and if it exceeds the upper limit, the conductivity decreases.

That is, although addition of Ti improves strength and heat resistance and makes crystals finer, excessive addition deteriorates not only conductivity but also manufacturability.

Addition of Mn improves strength and heat resistance as well as 90T properties, but excessive addition reduces conductivity.

Addition of Fe, Ni, and Co all improve strength and heat resistance, but excessive addition reduces electrical conductivity.

Although the addition of Hf, V, Y, and rare earth elements all greatly contribute to improving strength and heat resistance, excessive addition not only increases cost but also deteriorates manufacturability.

Addition of Ca and B not only improves strength and heat resistance but also acts as a deoxidizing agent and improves manufacturability, but excessive addition not only lowers conductivity but also conversely lowers heat resistance.

Although addition of 3n improves strength and heat resistance, excessive addition greatly reduces moldability and bondability.

Addition of 3i improves strength and heat resistance as well as acts as a deoxidizing agent and improves manufacturability, but excessive addition impairs conductivity and conversely worsens manufacturability.

〔Example〕

Tough pitch copper is melted in the air and in vacuum using a graphite crucible, Mq and Cr are added respectively, and then X element is added, after which it is cast into a mold to form a thick sheet having the alloy composition shown in Table 1. 25. An ingot with a width of 120 mm and a length of 150 mm was obtained.

Regarding these ingots, the surface is 2.5 mm per side.
After face cutting, heating and hot rolling at 850'C,
Next, cold rolling and intermediate annealing were repeated to obtain a plate with a thickness of 0.25 mm with a final processing rate of 30%.
C and finish annealing, and the conductivity, tensile strength, heat resistance, plating properties, oxide film removability, and hot workability were examined. These results are also listed in Table 1.

Electrical conductivity is based on JIS-HO505, tensile strength is J
Measured based on 15-Z2241.

The heat resistance was compared by heating the above plate materials at 450°C for 5 minutes and then measuring the Vickers hardness under a load of 500g. For plating properties, a 30# square sample was cut out from the above plate material, and after surface degreasing and pickling (dissolution to a surface thickness of 0.3μ), a 5μ thick A
Perform CT plating, heat treat it (450℃, 5 minutes), and check for blisters on the surface. Those with 0 blisters are marked with ◎, those with 2 or less are marked with 0, and those with 3 to 6 blisters are marked with ◎. For hot workability, surface cracks during hot rolling at 850'C were investigated, those with cracks are marked with X, and those with no cracks are marked with Δ. is indicated by a circle.

In addition, oxide film removability has a large effect on moldability and bonding properties, so a sample with a width of 10mm and a length of 5om was cut out from the above plate material, and after surface cleaning treatment, it was heated at 420°Q in the air for 1 minute. An oxide film is formed on the surface, and a peeling test is performed using cellophane tape. No peeling is observed at all with ◎, almost no peeling is marked with ○, and peeling is observed on the entire surface with X. Represented by a mark.

As is clear from Table 1, the present invention alloys No. 1 to No.
It can be seen that all of No. 18 exhibited substantially the same conductivity, plating performance, and hot workability as the conventional alloys No. 26 and No. 27, and exhibited far superior strength, heat resistance, and oxide film removability.

On the other hand, it can be seen that Comparative Alloys Nos. 19 to 25, which deviate from the alloy composition specified by the present invention, are inferior in at least one of the tested properties. That is, comparative alloy N with less Mg content
o, 19. Comparative alloy No. 21 with low Cu content.
Comparative alloy No. 23, which has a low content of X element, had poor tensile strength and heat resistance, and comparative alloy No. 20, which had a high fV1g content, had poor hot workability, so we gave up processing it into a plate material. . Comparative alloy No. 0.22 has a high Cr content, comparative alloy No. 24 has a high content of X element.
It can be seen that in No. 25, the electrical conductivity decreased significantly, and the plating properties, oxide film removability, and hot workability were inferior.

〔Effect of the invention〕

As described above, according to the present invention, the material has excellent strength, heat resistance, and bondability, and has a remarkable effect as a material for electronic devices that can respond to the miniaturization and high density of electronic devices in recent years. I have something to do.

Claims (1)

[Claims] Mg0.005-0.8wt%, Cr0.01-1.0
wt%, and further includes Ti, Mn, Fe, Co, Ni, H
One or more of f, V, Zn, Sn, Ca, B, Y, Si, and rare earth elements in a total of 0.003 to 0.
A copper alloy for electronic devices that contains 5 wt% and the balance is Cu and unavoidable impurities.