JPS60251250A - Alloy for lead frame for ic with superior corrosion resistance - Google Patents

Abstract

PURPOSE:To obtain the titled alloy capable of effectively preventing stress corrosion cracking by specifying a composition consisting of Ni, C, Mn, Pd, Ru and Fe. CONSTITUTION:This alloy for a lead frame for IC with superior corrosion resistance consists of, by weight, 35-55% Ni, <=0.05% C, <=2.0% Mn, 0.005-3.0% Pd and/or Ru and the balance essentially Fe or further contains 0.01-4.0% one or more among Cr, Mo, Nb, V, Zr, Ti and Ta. The corrosion resistance is remarkably improved without deteriorating the thermal expansion characteristics and hot workability, so stress corrosion cracking is prevented to increase the reliability of a semiconductor device or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a Fe-Ni
This invention relates to improving the corrosion resistance of alloys.

Conventionally, alloy 42 (Fe-41%N1) has been widely used as a material for lead frames of semiconductor devices because of its thermal expansion compatibility with semiconductor elements, glass, ceramics, and the like.

However, this alloy does not have sufficient corrosion resistance (it is known that lead breakage accidents due to stress corrosion cracking often occur during the manufacturing process of semiconductor devices or during use after being incorporated into various electronic devices).

Particularly recently, these semiconductor devices are required to have 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 causes of stress corrosion cracking. Efforts are being made to minimize the amount of remaining etching solution, pickling solution, plating solution, etc., or impurities in the sealing resin.

However, it is impossible to completely eliminate contamination by these corrosive substances, and the industry has been eagerly awaiting the development of an alloy with even better corrosion resistance than the conventional 42 alloy.

The present invention was made to improve the corrosion resistance of 42 alloy and eliminate the above-mentioned drawbacks.
55%, CO, 0596 or less, Mn 2.0% or less, Pd and Ru 1 or 2 types total 0.005
An alloy for ICIJ-de-frames with excellent corrosion resistance characterized by containing 3.0% and the remainder consisting essentially of Fe, and the above-mentioned alloy Nisa et al., Cr, Mo, Nb, V, Z
r, Ti.

The total amount of one or more of Ta is 0.01, 4.
ICI with excellent corrosion resistance characterized by containing 0%
This is an alloy for J-frames.

Next, we will discuss the reasons for limiting the composition of the alloy of the present invention.Ni is the basic component of the present alloy.
If it exceeds 5 cm, the coefficient of thermal expansion of the alloy becomes too large, making it impossible to maintain compatibility with semiconductor elements, glass, or ceramics. For this reason, Ni was set at 3-55%.

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.

Although Mn has the effect of improving the hot workability of the alloy, Mn is limited to 2.0% or less since containing too much will lead to an increase in the coefficient of thermal expansion, which is a basic characteristic of this alloy.

Pd and Ru have a great effect on improving corrosion resistance, which is the objective of the present invention, but if either one or the total of the two is less than 0.005%, a sufficient effect cannot be obtained; on the other hand, if it exceeds 30%, The effect reaches saturation and seriously impairs hot workability.
It spread out.

In addition, Cr, Mo, Nb, V, Zr, Ti, and Ta are also alloying elements that are included to improve the corrosion resistance of this alloy, and the total amount of one or more of them is 0.01.
If it is less than 4.0%, the effect cannot be obtained, and conversely, if it exceeds 4.0%, the influence on the thermal expansion characteristics cannot be ignored.
01 to 4.0.

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

An alloy having the composition shown in the table is melted and cast in a vacuum high-frequency induction furnace, and then forged at a temperature of 1000°C to 1100°C.

After hot rolling, repeated cold rolling and softening annealing,
A plate with a thickness of 'g0.101Ji was finished at a final cold rolling rate of 50%. After that, a sample with a width of 1 and a length of 40 was cut out from this material by photo etching and heated at 150°C.
A sample sealed with resin in the shape shown in the figure at a temperature of 200°C was left in a high temperature and high humidity environment at a temperature of 85°C and a relative humidity of 95% for 2000 hours, and the frequency of cracking in the sample at that time was investigated. . The test was conducted on 50 samples for each group. The results are also shown in the table.

As is clear from the results in the table, conventional alloy (alloy number 1)
It can be seen that the alloys of the present invention (alloy numbers 2 to 21) have a lower frequency of cracking and have better corrosion resistance.

As explained above, the present invention does not impair the thermal expansion characteristics and hot workability of alloy 42 for IC lead frames.
Corrosion resistance can be significantly improved, and the reliability of semiconductor devices and even electronic products can be improved, and the industrial effects are extremely large.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the sample. 11 samples 2I sealing resin First country procedure amendment (method) % formula % Fa November (7) Name Name of the person who makes the alloy uramasa for lead frames with corrosion resistance (508) Hitachi Metals, Ltd. Company representative Norio Kono Date of order to amend August 28, 1980 (shipment date) Attached is the table on page 5 of the "Detailed explanation of the invention" section of the description of the subject matter of the amendment. Correct as follows. (No change in content)

Claims (1)

[Claims] t: 55 to 55% Ni by weight, eo: 05% or less,
One or two types of Pd and Ru in Mn 2.0% or less
The total species contains o, oos ~ 6.0%, and the remainder is substantially F.
e, J: Alloys for IC lead frames with excellent corrosion resistance characterized by bending. 2, ii% Te Ni35~55%, Co, oF) e4
Hereinafter, Mn of 2.0 or less K Pd and Ru are contained in a total of 0.005 to 5.0% of one or both of them, and C
r, Mo, Nb, V, Zr. One or more of Ti and Ta in total 0.01
An alloy for use in ICIJ-bond frames with excellent corrosion resistance, characterized in that it contains ~4.0% and the remainder is substantially Fe.