JPS60238450A - Alloy for lead frame for ic with superior corrosion resistance - Google Patents

Abstract

PURPOSE:To obtain an alloy for a lead frame for IC with superior corrosion resistance by adding specified amounts of C, Mn and Cu to an Fe-Ni-Co alloy. CONSTITUTION:The composition of the alloy for the lead frame for IC is composed of, by weight, 10-33% Ni, 10-20% Co, <0.05% C, <2% Mn, 2-15% Cu and the balance Fe. The total amount of Ni and Cu is regulated to 25-35%. It is preferable that 0.01-4% in total of one or more among Cr, Mo, Nb, V, Zr, Ti and Ta are further contained in the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to Fe-Ni used in IC lead frames.
This invention relates to improving the corrosion resistance of -Co alloys.

42 alloy (Fe-414Ni) in terms of thermal expansion compatibility with semiconductor devices, glass, ceramics, etc.
and Kovar alloy (Fe-29'A Ni-17%C
o) is widely used.

However, this alloy does not have sufficient corrosion resistance, and it is known that lead breakage accidents due to stress corrosion cracking may occur during the manufacturing process of semiconductor devices or during use after being incorporated into each scale electronic device. It is being

Particularly recently, these semiconductor devices have come to be required to have even higher reliability than ever before in fields such as nuclear power and aircraft, and semiconductor device manufacturers are also concerned about contamination by corrosive substances, which is one of the key signs of stress corrosion cracking. (For example, photo-etching liquid, acidic liquid.

Remaining plating solution, etc. or unsightly items in the sealing resin 1)
However, it is impossible to completely eliminate contamination from these corrosive substances, and the industry is developing alloys that are even more resistant to corrosion than traditional Kovar alloys.

The present invention improves the corrosion resistance of the Fe-Ni-Co alloy,
It was expressed in order to eliminate the above-mentioned drawbacks, and in terms of weight% Ni 10-55% r Co 10-20% +
CO, 05% or less + Mn 2.0% or less, Cu2-1
I with excellent corrosion resistance, containing 5% Ni%XCu%, with the balance being substantially more than Fe.
CIJ-deframe alloy, and the above alloy further contains C.
r + Mo, Nb r V r Zr + Ti
+ One or more of Ta in total of 0.01
I with excellent corrosion resistance characterized by containing ~4.0
This is an alloy for C lead frames.

Next, the reason for limiting the composition of the alloy of the present invention will be described.

Ni and Co l Cu are limited due to the thermal expansion coefficient, which is a basic property of this alloy, and the amount of N + Cu is limited.
% is less than 25% or more than 35% or C
If o is less than 10 inches or more than 20 inches, the coefficient of thermal expansion of the alloy will be too large, making it impossible to maintain compatibility with the conductor Yonago, glass or ceramics. For this reason, Ni is 10 to 33%.

Cu is 2-15% r Co is 10-20% and Ni
If too much +C is contained, carbides will form in the alloy and the corrosion resistance will deteriorate, so the content is set to 0.05% or less.

Seeds have the effect of improving the hot workability of the alloy, but their content was limited to 2.0% or less because excessively large amounts would lead to an increase in the coefficient of thermal expansion, which is a basic characteristic of this alloy.

Cu has a great effect on improving corrosion resistance, which is the objective of the present invention, but if it is less than 2%, this effect cannot be obtained, and on the other hand, if it exceeds 15%, the effect is saturated and hot workability is significantly reduced. It was set at 2 to 15 inches to make it more harmful.

Also, Cr r Mo + Nb+ V * Zr +
Ti and Ta are also alloy elements that are included in order to improve the corrosion resistance of this alloy, but if only one type is used and the total of two or more types is less than 0.01 inch, the effect cannot be obtained;
Since the influence on thermal expansion characteristics cannot be ignored if it exceeds 0.01 to 4.0.

The present invention will be explained below with reference to Examples.

The alloy with the composition shown in the table is melted and cast in a vacuum high-frequency induction furnace, then forged and hot rolled at a temperature of 1000℃ to 1100℃, and then repeated between column rolling and softening annealing, with a final cold rolling rate of 30%. It was finished into a plate material with a thickness of 0.10 mm. After that, a sample with a width of 1 m and a length of 40 Ily+ was cut out from this material by photoetching, and heated at 150°C to 200°C.
The resin-sealed product was molded into the shape shown in the figure at a temperature of 85 °C and a relative humidity of 95 °C for 2000 °C in a high temperature and high humidity environment.
The sample was left for a certain period of time, and the frequency of cracking in the sample at that time was studied.

Each test was conducted on 50 samples for each alloy.

The results are also shown in the table.

As is clear from the results in the table, compared to the conventional alloy (alloy number 1), the alloys of the present invention (alloy numbers 2 to 13) crack less frequently and have good corrosion resistance.

As explained above, according to the present invention, the thermal expansion characteristics, hot temperature resistance, and workability of alloy 42 for IC lead frames can be improved. i
Tom )-J-fp/ Ichito Itoki Toka Sheep 1 What
It is possible to improve the reliability of semiconductor devices and, in most cases, electronic products, and has extremely large industrial effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the sample. 悴　　图

Claims (1)

[Claims] 1% by weight: 10 to 56% Ni and 10 to 20% Co. CD, 05% or less, Mn 2.0% or less, Cu2-1
I with excellent corrosion resistance, characterized in that the total amount of Ni and Cu is 25 to 55% and the balance is substantially more than Fe.
Alloy for C lead frame. 2 Ni 10 to 33 pieces, 6010 to 20%. CD, 05% or less, Mn 2.0% or less, Cu2-1
Cr Mo + Nb + V * Zr +
Ti * One type of Ta and two or more types with a total of 0.
1. An alloy for use in I, CIJ-bonded frames with excellent corrosion resistance, characterized in that it contains 01 to 4.0% Fe, and the remainder consists essentially of Fe.