JPS60238445A - 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 Ru and/or Pd to an Fe-Ni- Co alloy. CONSTITUTION:The composition of the alloy for the lead frame for IC is composed of, by weight, 25-35% Ni, 10-20% Co, <0.05% C, <2% Mn, 0.005-0.5% in total of Ru and/or Pd and the balance Fe. 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] Fe-Ni used in the IC lead frame of the present invention
This invention relates to improving the corrosion resistance of -Co alloys.

Conventionally, materials for lead frames of semiconductor devices include:
42 alloy (Fe-41% Ni) and Kovar alloy (Fe-29% Ni-17'1Co) in terms of thermal expansion compatibility with semiconductor elements, glass, ceramics, etc.
is widely used.

However, this alloy does not have sufficient corrosion resistance, and is often incorporated into semiconductor device manufacturing processes or various electronic devices.
It is known that Shiba 17 leads to lead breakage due to stress corrosion cracking during subsequent use.

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 presence of photoetching solutions, pickling solutions, plating solutions, and impurities in sealing resins.

1-7 It is impossible to completely eliminate contamination from corrosive substances, and the industry has been eagerly awaiting the development of an alloy with even better corrosion resistance than the conventional Kovar alloy.

The present invention improves the corrosion resistance of Fe-Ni-Co alloy11
, was made to eliminate the drawbacks as mentioned above,
Ni25-35%, 0010-20% by weight.

CD, 0.05% or less, R4n 2 , 0% or less, and one or both of Ru and Pd in a total of 0.00'5 to 0.00%.
An alloy for IC lead frames with excellent corrosion resistance characterized by containing 50% Cr + Mo + Nb and V+Zr with the remainder being substantially KFe.
0.0 in total of one or more of +Ti+Ta
It is an alloy for IC lead frames with excellent corrosion resistance, which is specially designed to contain 1 to 4.0% of C.

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

Ni and Co are the basic components of this alloy, with Ni being 25
If Co is less than 35% or more than 35%, or if Co is less than 10% or more than 20%, the coefficient of thermal expansion of the alloy becomes too large and compatibility with semiconductor elements, glass, or ceramics is not maintained. It disappears. For this reason, Ni
25 to 35%, and 0.05 to 35% Co. If too much C is contained, carbides are formed in the alloy and the corrosion resistance is deteriorated.
% 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 may lead to an increase in the coefficient of thermal expansion, which is a basic characteristic of the present alloy.

Ru and Pd have a great effect on improving corrosion resistance, which is the objective of the present invention, but if either 1's or the total of the two is less than 0.005, a sufficient effect cannot be obtained; If it exceeds 0.005%, the effect will reach saturation and the hot workability will be significantly impaired.
It was set to 0.5%.

Also Cr' r Mor Nb T V r Zr
+ Tl and Ta are also alloying elements that are included in order to improve the corrosion resistance of this alloy, but if the total amount is less than 0.01% of 1st grade or 2# or more, no effect can be obtained;
．． If the content exceeds 0%, the influence on the thermal expansion characteristics cannot be ignored, so the content was set at 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°C to 1100°C, and then cold rolled and softened annealed repeatedly to achieve a final cold rolling reduction of 60%. A plate material with a thickness of 0.10 mm was completed. After that, a sample with a width of 1 inch and a length of 40 mm was cut out from this material by photoetching, and the sample was sealed with resin at a temperature of 150 to 200 degrees Celsius as shown in the figure.
The samples were left in a high temperature and high humidity environment at 5° C. and relative humidity of 95% for 2000 hours, and the frequency of cracking in the samples at that time was evaluated. 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 12) crack less frequently 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 use in r' Cl -de frames without impairing its thermal expansion characteristics and hot workability, thereby improving the reliability of semiconductor devices and, ultimately, electronic products. High reliability can be achieved, and the industrial effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the sample. 1: Sample 2: Sealing resin Part l @

Claims (1)

[Claims] 1% by weight: 25 to 65 inches of Ni + 10 to 20 inches of Co. C 0.05% or less, Mn 2 , 0% or less, Ru and Pd in one or two types total of 0.005 to 0.5
An alloy for use in ICIJ-bonded frames with excellent corrosion resistance, characterized in that it contains iron and the remainder is substantially made of Fe. 2. Weight f% is Ni 25-65%, Co 10-20%. CD, 0.05% or less, Mn 2 , 0% or less, Ru and Pd are contained in 1 m or 0.005 to 0.5 t in total of the two types, and further Cr + Mo + Nb + V *
An alloy for IC lead frames with excellent corrosion resistance, characterized in that it contains two or more types of Zr+Ti *Ta in a total of 0.01 to 4.0% for each penetration, and the remainder is substantially Fe.