JPS60251251A - 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, B 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, 0.0005-0.5% B 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 relates to Fe-Ni used in IC lead frames.
This invention relates to improving the corrosion resistance of alloys.

Conventionally, alloy 42 (Fe-41% Ni) 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, and it is known that lead breakage accidents often occur due to stress corrosion cracking 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 hole resistance of 42 alloy and eliminate the above-mentioned drawbacks.
55%, C0.05% or less, Mn2.0% or less
An alloy for IC lead frames with excellent corrosion resistance, characterized by containing 0.0005 to 0.05% of Cr, the remainder being substantially Fe, and the above alloy, in addition to K Cr, Mo, N.
b.V.

This is an alloy for ICIJ-bond frames with excellent corrosion resistance, which is characterized by containing one or more of Zr, Ti, and Ta in a total amount of 0.01 to 4.0%.

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

Ni is a basic component of this alloy, and if Ni is less than 35% or more than 55%, the thermal expansion coefficient of the alloy will become too large, making it difficult to maintain compatibility with conductive elements, glass, or ceramics. So, Ni is 35.
It was set at 55 chi.

If too much C is contained, carbides will form in the alloy and the corrosion resistance will deteriorate, so the content is set to be less than 005.

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.

B has a great effect on improving corrosion resistance, which is the objective of the present invention, but if it is less than 0.00054, a sufficient effect cannot be obtained, while if it exceeds 0.5%, the effect is saturated and hot workability is reduced. 0 as it will cause significant harm to
．． 0005 to 0°5.

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 the ratio is less than 4.0%, the effect cannot be obtained, and if it exceeds 4.0%, the effect 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 was melted and cast in a vacuum high-frequency induction furnace, then forged and hot rolled at a temperature of 1000°C to 1100°C, followed by cold rolling and softening annealing.

Then, the final cold rolling rate was 30 to make a plate with a thickness of 0.1 DB.

Finished. After that, width I II and length 40 are made from this material.
A sample of 150° was cut out by photoetching.
Resin seal in the shape shown in the figure at a temperature of 0°C to 200″C.

The temperature was 85℃ and the humidity was 95℃.

Cracking of the sample after being left in humidity for 2000 hours 1
．． .

We investigated the degree. The 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 18) have a lower frequency of cracking and have better corrosion resistance.

As explained above, according to the present invention, it is possible to significantly improve the corrosion resistance of alloy 42 for ICIJ-deframes without impairing its thermal expansion characteristics or hot workability, thereby improving the reliability of semiconductor devices and, ultimately, electronics and products. High reliability can be achieved, and the industrial effect is extremely large.

[Brief explanation of drawings]

Figure 1 is a perspective view of the sample. 11 Samples, 2I Encapsulation Resin Procedural Correction Form (Method) % Formula % Invention (7) Name Name of person who corrects the corrosion resistant lead frame alloy (!10111 Hitachi Metals Co., Ltd. Representative Kono Date of amendment order: August 28, 1980 (shipment date) Contents of the amendment in the "Detailed Description of the Invention" column of the specification to be amended The table on page 5 of the specification is corrected as shown in the attached sheet. (No change in content) Procedural amendment (Own ship 13□+69.5'+12311 Invention by Commissioner of the Japan Patent Office+7) Name Name of the person who will repair the alloy for 7tIO! J-Door 7Ram with excellent good resistance (fi081 Hitachi Metals Co., Ltd.) 2nd party: Norio Kono (Representative) Corrected the #m'lk explanation column of the invention in the specification subject to personal amendment.

Claims (1)

[Claims] 1. Ni 35-55%, CO, 0.5% or less, Mn 2.0 by weight i%. Excellent corrosion resistance characterized by containing 0.0005 to 0.5% of B below H, with the balance essentially consisting of Fe. Alloy for ICIJ-de frames. 2. Weight: Ni 55-55%, CD, 05%
Below, 0.0005 to 0.5% B is added to Mn 2.0 or less.
It also contains Cr. One of Mo, Nb, V, Zr, Ti, Ta
An alloy for IC lead frames having excellent corrosion resistance, characterized in that it contains one or more species in a total amount of 001 to 4.0, and the remainder is Fe in terms of carbon content.