JPS60238444A - 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 Ge and/or Si 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, 0.05-0.5% in total of Ge and/or Si 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] BJII is a Fe material used in IC lead frames.
-Ni-Co alloy 42 alloy (Fe-41% Nt) and Kovar alloy (Fe-29%Ni-17%Co) are widely used.

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.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 residual photoetching solution, acid reflux solution, plating solution, etc., or impurities in the sealing resin.

However, 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 was made in order to improve the corrosion resistance of Fe-Ni-Co alloy and eliminate the drawbacks mentioned above.
C[], 0.5% or less, Mn 2.0% or less with Ge
and St of 0.005 to 0.005 to 0.005 to 0.1 or 2n in total.
An alloy for IC lead frames with excellent corrosion resistance characterized by containing 5% and the remainder consisting essentially of Fe, and the above alloy further comprising Cr + Mo + Nbr V +
The alloy for IC lead frames has excellent corrosion resistance and is characterized by containing one or more of Zr + Tt + 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
Co and Ni, which is the basic component of the main alloy, may exceed 35% when the content is less than 25%.

If Co is less than 10 or more than 20g6, the coefficient of thermal expansion of the alloy will be too large, making it impossible to maintain compatibility with semiconductor elements, glass, or ceramics.

Therefore, Ni is 25 to 35 cm, C.

If too much C is contained, it will form carbides in the alloy and deteriorate the corrosion resistance, so it is limited to 0.05% or less.Mn is effective in improving the hot workability of the alloy, but if it is contained too much, the alloy will deteriorate. Ge and Si are limited to 2.0 inches or less in order to increase the coefficient of thermal expansion, which is a basic characteristic of Take 2
The total number of species is 0. [1() If it is less than 5%, a sufficient effect cannot be obtained, and if it exceeds 0.5%, the effect will be saturated and the hot workability will be significantly impaired, so 0.005
~0.5%.

Also Cr + Mo + Nb * V * Zr r
Ti and Ta are also alloying elements that are included to improve the corrosion resistance of this alloy, but if the total of two or more elements is less than 0.01 Ti, the effect cannot be obtained;
If the value exceeds 0, the effect on thermal expansion characteristics cannot be ignored.

The ratio was 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 cold rolled and softened annealed repeatedly to achieve a final cold rolling reduction of 30%. A plate with a thickness of D and 10wm was completed. After that, a sample with a width of 1 inch and a length of 40 m was cut out from this material by photoetching, and the sample was sealed with resin at a temperature of 150°C to 200°C in the shape shown in the figure.
The samples were left in a high-temperature, high-pressure environment at a temperature of 85° C. and a relative humidity of 95% for 2,000 hours, and the frequency of cracking in the samples at that time was investigated. Each test sample was omitted for 50 samples for each alloy. The results are shown in the table.O 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) have a lower frequency of cracking and have better corrosion resistance. As explained above, according to the present invention, the thermal expansion characteristics and hot workability of the 42 alloy for T C'J-frames are significantly improved in size A and corrosion resistance. However, the reliability of semiconductor devices and, by extension, the reliability of electronic products can be improved, and the industrial effect is extremely large.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the sample. 1: Sample 2゛Sealing resin Figure 1''+14 (7) 8 i'''゛Y, 1゜,.
. ”) )'7L/-jJ*Yunyu 1
Bamboo +5og+ I] Ritsu Metal Co., Ltd.] - Representative
Norio Kono

Claims (1)

[Claims] 1% by weight: Ni 25-35%, Co 10-20%. co, os% or less, 'Mn2.0% or less with Ge and S
An alloy for IC lead frames having excellent corrosion resistance, characterized in that it contains 0.005 to 0.5 of one kind or two kinds of t in total, and the balance is substantially composed of Fe. Type 2 bone chi, Ni 25-35 chi, Co 10-20 chi. CD, 05% or less, Mn 2-0% or less, Ge and St are contained in a total of 0.005 to 0.5 of one or two types, and further Cr + Mo + Nb + V + Z
One or more of r + TLTa in total of 0.
An alloy for IC lead frames having excellent corrosion resistance, characterized in that it contains 01 to 4.0% Fe, and the remainder is substantially Fe.