JPH03219051A - Fe-ni alloy for lead frame and its manufacture - Google Patents

Abstract

PURPOSE:To obtain an alloy for a lead frame having more excellent hardness and tensile strength as well as higher deformation resistance compared to those of a conventional one without impairing its low thermal expansibility by adding specified elements to an Fe-Ni series alloy. CONSTITUTION:As the material for an IC lead frame, an Fe-Ni series alloy constituted of, by weight, 30 to 55% Ni, <2% Co, 0.01 to 2% Be, <1% Mn, <0.5% Si, <5% Cu, <0.1% C and the balance Fe is independently incorporated with at least one kind of 0.01 to 2% Al and 0.01 to 2% Ti or independently incorporated with at least one kind among 0.01 to 1% Nb, 0.01 to 4% Mo, 0.01 to 4% W, 0.01 to 1% V, 0.01 to 3% Cr, 0.001 to 0.5% B, 0.001 to 1% Zr and 0.001 to 1% misch metal, or the above incorporation is compositely executed. The Fe-Ni series alloy material for a lead frame having low value of thermal expansibility equal to that of a silicon element or ceramics for sealing as well as excellent in hardness and tensile strength and having high deformation resistance can be obtd.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a Fe-Ni alloy suitable as a lead frame material for multi-pin ICs and a method for producing the same, by adding a specific element in a specific amount. The present invention relates to a material that exhibits better deformation resistance than conventional alloys and has low thermal expansion comparable to that of conventional alloys, and a method for producing the same.

"Conventional technology" In recent years, the development of highly integrated large-scale integrated circuits (LSI) and superhuman-scale integrated circuits (ultra-LSI) has become active. In I, silicon elements have become larger and generate more heat. Therefore, if the difference in thermal expansion coefficient between the silicone element and the lead frame is large, the silicon element may be subject to thermal stress due to expansion and contraction of the lead frame due to heat generated by electricity, and may break or crack.

Therefore, in the case of lead frame materials for LSIs and VLSIs, it is particularly necessary to bring the coefficient of thermal expansion close to that of silicon elements.

For this reason, 42A has traditionally been used as a material for lead frames as a low-expansion Fe-Ni alloy for the purpose of alleviating thermal stress that acts on solicon elements.
1loy (42%N1-Fe) (JP-A-5511915
No. 6), Kovar (29%Ni-17%co-Fe)
), and low expansion Kovar (29%Ni-13%Co
-FeX JP-A-59-198741) and the like are known.

``Problems to be solved by the invention 1 However, recently, with the increase in the number of pins in lead frames, the inner lead width has changed from 0.3 to 0.5 +++ m to 0.1 to 0.2 mm. In addition to this, there is also a tendency for external leads to become narrower.

For this reason, the material strength of the lead is insufficient, and the lead may be deformed due to external force during the manufacturing process, during transportation, taping the separator, or when connecting to the board. This is becoming a serious problem.

Therefore, the inventors of the present application first filed the patent application No. 63-315 G.
No. 46 Specification 7jF, Patent Application No. A1-164582 Specification 1
1F, Japanese Patent Application No. 172509 No. 1, describes an alloy in which high strength and low thermal expansion are ensured by adding a specific amount of Be or other elements thereof to a Fe-N1-Go alloy. A patent application has been filed.

In these patent applications, Ni30-55%, 00
2% or less, f3c 0.01-2%, M n 1% or less,
The composition of Si is 0.5% or less, Cu is 5% or more, and C is 0.1% or less. Achieved.

The present invention was made in order to solve the above problems by further developing the technology for which the inventors of the present invention have previously applied for a patent, so it has better hardness and tensile strength than conventional alloys, and is close to Noricon elements. The object of the present invention is to provide a Fe--Ni alloy for lead frames that exhibits a low coefficient of thermal expansion and a method for producing the same.

"Means for solving the problem" The invention stated in claim 1 solves the problem n.
N130-55%, Co 2% or less, B c0.01~
2%, M n I% or more, Si 0.5% or less, Cu 5%
Below, the composition contains 0.1% or less of C, 0.01 to 2% of A1 and 0.01 to 2% of 'I' i, including at least (J1 type), and the composition of the remaining Fe and unavoidable impurities. It is something.

In order to solve the above-mentioned problem, the invention as set forth in claim 2 uses Ni30 to 55%, Co2% or more, [3eo, 01 to
2%, Mn 1% or less, Si 0.5% or more, Cu5
% or less, including C0.1% or less, and 0.01 to 1% Nb
and 0.01-1% Mo and 001~/I% W and 0.0
1-1% V and 0.01-3% Cr and 0.001-0
．． 5% 13 and 0001~1% Zr and 0.001-]
% of MiSotsuyu metal, and has a composition of Fe remainder and unavoidable impurities.

In order to solve the above problem, the invention described in claim 3 has the following features:
Ni30-55%, Co2% or less, r3e0.01-2
%, Mn 1% or less, Si 0.5% or less, (including 305% or less, C 0.1% or less, 0.01 to 2% A1 and 0
．． 0.01 to 2% of Nb, 0.01 to 1% of Mo, and 0.01 to 1% of Mo.
01-4% W, 0.01-1% V and 0.01-3%
of Cr and 0.001-0.5% of 13 and 0.001-1
% of Zr and 0.001~1% of Misotsuyu metal,
The composition contains at least one or more kinds of Fe, the remainder of Fe, and unavoidable impurities.

In order to solve the above problem, the invention described in claim 4 has the following features:
The raw materials are blended to satisfy the composition described in claim 1, claim 2, or claim 3, and the ingot obtained by melting is subjected to plastic pressing and annealing treatment until the desired shape is obtained, and after final plastic working. It is aged in a temperature range of 300 to 700°C.

]-Effect By placing Fe, Ni, Co&Mn, Si, Cu, and C (f) into an alloy with a low expansion coefficient, adding a small amount of 13e increases its strength. Since only a small amount is required, the main component of the alloy is an alloy with a low coefficient of expansion, which ensures a suitable coefficient of thermal expansion as a material for a lead frame.Furthermore, in the above composition, at least one of A1 and Ti is added. Strengthening by precipitation hardening is achieved by adding a predetermined amount of one of them, followed by Nb and M.

By adding specific n1 of at least one of the following: and~■, V, Cr, 13, Zr, and misotsuyu metal, it is strengthened by solid solution strengthening.

Further, when an alloy having a Moekiya composition is heat treated at 300 to 700°C, the tensile strength can be controlled and age hardening occurs.

The present invention will be explained in more detail below.

In the alloy of the present invention, Ni is added to 30-5
5%, (10 (cobalt) 2% or less, 3e (Heliru 1.) 0.01 to 2%, M II (7 ngan) 1% or less, Si (silicon) 0.5% or less, Cu (copper)
It is mainly an alloy containing H of 5% or less and C (carbon) of 0.1% or less.

0.01 to 2% of Al (aluminum) and 0.01 to 2% of 'I''i (titanium) are added to the alloy mainly having the above composition.

In addition, in alloys mainly having the composition 1ji7, 0.0I~
1% Nb (niobium), 001~4% Mo (molybdenum), 0.01~4% W (tungsten), and 0.01
-1% v(vanadium) and 0.01-3% v)cr(
chromium), 0.001 to 0.5% B (boron), and 0.001 to 0.5% B (boron).
001-1% Zr (zirconium) and 0.001-1
% Misotsuyu metal (mixed rare earth metal) 1"), at least one or more independently, or +"+: i A
1 and Ti together with at least II.

In the above composition, does it contain Ni, Co, and Cu? If Tffi is outside the above range, it is not preferable because the lead frame material will not be able to obtain a coefficient of thermal expansion that is compatible with the coefficient of thermal expansion of the silicon element, etc. to which it is applied.

If the r3c content is less than 0.01%, it is inconvenient that the desired strength cannot be obtained even with the cooperation of other additive elements, and if the Be content exceeds 2.0%, the strength will decrease. Despite the improvements, it is expensive and the amount of e used increases, resulting in high costs, making it unsuitable.

Si is used as a deoxidizing agent, but the ffff1 content is 0.5%.
If the content exceeds 1%, the alloy becomes brittle, which is disadvantageous. Mn improves forgeability and is used as a deoxidizing agent, but if the content exceeds 1%, it deteriorates workability, which is not preferable.

When C exceeds 0.1%, workability deteriorates.

If the content of each of A1 and Ti is less than the lower limit value, the desired strength cannot be obtained, and if it exceeds the lower limit value, the cost becomes high despite the improvement in strength, and a preferable coefficient of thermal expansion cannot be obtained.

If the content of Nb, Mo, W, V, Cr, B, Z r, and misch metal is less than the lower limit, the desired strength cannot be obtained, and if it exceeds the upper limit, the cost will be high despite the strength improvement. Therefore, a preferable coefficient of thermal expansion cannot be obtained.

To produce the alloy, first, raw materials are blended to have the above composition, and then vacuum melting is performed in an atmosphere such as Ar gas to avoid contamination with impurities to obtain an ingot with the above composition. .

Next, this ingot is forged at +200 to 1400°C, rolled to the desired shape, for example, to the desired thickness, preferably at a processing rate of 70% or less, and then
The annealing treatment at 00 to 1100°C is repeated as many times as necessary. Then, the processing rate is preferably set to 5 during the final rolling process.
0% or less, and after the final rolling, a heat treatment is performed in a temperature range of 300 to 700° C., preferably within 5 hours, for the purpose of age hardening treatment, to obtain a plate material with a desired thickness.

If the aging treatment temperature is below 300°C, the precipitated particles will be too small and precipitation hardening will not proceed, resulting in unaged 700°C.
At temperatures above ℃, the heat treatment time until the strength reaches its peak due to aging is too short, making temperature control difficult; above this temperature, the precipitate particles become too sensitive and sufficient precipitation hardening cannot be expected. There is a possibility that the strength will be reduced.

If an alloy with the above composition is manufactured using the manufacturing method described above, it will have higher strength and deformation resistance than conventional alloys, and will also have a thermal expansion coefficient close to that of Noricon elements and ceramic sealing materials. It is possible to obtain materials for lead frames with high yields. However, since the tensile strength of the alloy can be adjusted by adjusting the temperature and time of the aging treatment, it is possible to obtain a glued frame material with a desired strength. Furthermore, Be
Since the effect of improving the tensile strength can be obtained with a small amount of addition, the amount of expensive e used can be reduced, resulting in an effect that production can be carried out at low cost.

"Example" Raw materials were blended to have the compositions shown in Tables 1 to 4 below, and the valley compound was melted in a vacuum atmosphere of 80 Torr containing Ar gas to create an ingot. This ingot was subjected to hot forging at +200 to 1400°C, then rolled at a processing rate of 70% or less, and annealed by heating to 800 to 1100°C and then gradually cooled, followed by final rolling. The rolling process was completed at a processing rate of 50% or less, and then heated to 500°C for 2 hours.
A heating treatment was performed to obtain plate-shaped test pieces of samples Nos. 1 to 92.

h Tensile strength (kg/mm2) and hardness (Ilv) of test piece
) and ・T uniform thermal expansion coefficient (30-300℃, x I O-
8/'C) was determined as dl, and the results are shown in Tables 1 to 4.

(Hereinafter, blank space) From the results shown in Tables 1 and 1, it becomes clear whether the range limited by the present invention is appropriate for A1 and Ti gold platinum-'+t, and it is also clear that Nb and MO It has become clear that the ranges limited by the present invention are appropriate with respect to the UN containing W, V, Cr, +3, Zr, and misch metal.

On the other hand, the relationship between the aging treatment time and the tensile strength was determined for the samples of the invention products manufactured by the above procedure.

The results are shown in FIG.

As is clear from Figure 1, the aging treatment temperature was 300°C.
In the case of 500°C, the tensile strength increases in a gentle curve as the processing time progresses, reaching a peak after about 5 hours of processing time, and in the case of 500°C, the peak tensile strength is shortened to about 2 hours, In the case of °C, the peak is shortened to about 1 hour, but the tensile strength after 1 hour has decreased.

In view of the results shown in FIG. 1, in the method of the present invention, the aging treatment temperature is limited to a range of 300 to 700°C.

1 Effects of the Invention j As explained above, according to the present invention, F c, Ni, co, l! : A small amount of Be is added to an alloy with a low thermal expansion coefficient containing Mn, Si, Cu, and C in a predetermined age, and further Al and T are added.
At least one of i, or Nb, Mo, W, V, and C
It has high strength by adding at least one of r, B, Zr, and misch metal, so it maintains a thermal expansion coefficient close to that of Noricon elements and sealing ceramics, and has superior 6 hardness and tensile strength than conventional products. It is possible to provide an alloy with high deformation resistance.

Therefore, according to the present invention, it is possible to provide an excellent alloy for lead frames that does not apply thermal stress due to thermal history to the solicon elements or sealing ceramics, and whose leads are less susceptible to deformation due to external forces.

On the other hand, if the alloy with the above composition is heat treated at 300 to 700°C, it can be age hardened, so it is possible to control values such as tensile strength by selecting aging conditions, and achieve the desired tensile strength and It is possible to obtain an alloy suitable for lead frames having hardness.

[Brief explanation of drawings]

Figure 1 shows the relationship between the tensile strength of the test piece and the aging treatment time.
1- It is a graph.

Claims (1)

[Claims] (1) Ni 30-55% (weight %, the same applies hereinafter) Co 2%
Below Be 0.01-2% Mn 1% Si 0.5% Cu 5% C 0.1% or less, At least one of 0.01-2% Al and 0.01-2% Ti An Fe-Ni alloy for lead frames having a composition including: Fe balance and unavoidable impurities. (2) Ni 30-55% Co 2% or less Be 0.01-2% Mn 1% or less Si 0.5% or less Cu 5% or less C 0.1% or less, including 0.01-1% Nb and 0.01-4% Mo, 0.01~4% W, 0.01~1% V, 0.01~3% Cr, 0.001~0.5% B, and 0.001~1% Zr. An Fe-Ni alloy for a lead frame, which contains at least one kind of misch metal in an amount of 0.001 to 1%, and has a composition of Fe balance and unavoidable impurities. (3) Ni 30-55% Co 2% or less Be 0.01-2% Mn 1% or less Si 0.5% or less Cu 5% or less C 0.1% or less, 0.01-2% Al and 0.01-2% Contains at least one of Ti, 0.01-1% Nb, 0.01-4% Mo, 0.01-4% W, 0.01-1% V and 0.01 Contains at least one of ~3% Cr, 0.001~0.5% B, 0.001~1% Zr, and 0.001~1% misch metal, with the remainder of Fe and unavoidable impurities An Fe-Ni alloy for lead frames having the composition. (4) The raw materials are blended to satisfy the composition described in claim 1, claim 2, or claim 3, and the ingot obtained by melting is subjected to plastic working and annealing treatment until the desired shape is obtained, and the final plastic Fe-N for lead frames that is aged in a temperature range of 300 to 700°C after processing
Production method of i-alloy.