JPS63297531A - Copper alloy for terminal and lead frame having excellent hot workability and its production - Google Patents

Abstract

PURPOSE:To produce the titled copper alloy having excellent hot workability by regulating the impurity content to the specific amt. in the copper alloy contg. specific ratios of Ni, Si, Mn, Zn, Sn, Mg, Cr, Ti and Zr. CONSTITUTION:The copper alloy contg., by weight, 2.0-3.5% Ni, 0.5-0.9% Si, 0.01-1.0% Mn, 0.1-5.0% Zn, 0.1-2.0% Sn and 0.001-0.01% Mg and furthermore contg. one or more kinds among 0.001-0.01% Cr, Ti and Zr is prepd. As the impurity content in said copper alloy, <=0.002% Pb, <=0.001% Bi, <=0.001% S, <=0.001% Sb, <=0.001% As, <=0.0005% Te and <=0.0005% Se are regulated and hot rolling is started at 700-850 deg.C. By this method, copper alloy for terminals and lead frames in which no cracks are generated during hot working is produced with good productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a copper alloy for terminals and semiconductor lead frames having excellent hot workability, and a method for manufacturing the same.

[Prior Art] In recent years, many copper alloys have been developed for use in terminals and lead frames, but these alloys cannot necessarily be said to have excellent hot workability.

Factors that affect hot workability include impurities, chemical composition, grain size, crystallized substances, precipitates, processing temperature, deformation rate, etc.

In particular, many studies have been conducted on the effects of impurity elements on the hot workability of copper alloys, including Pb, Bi,
, S, Te, Se, Sb, Te, etc., there are reports on the permissible ranges for alloys such as brass, nickel silver, and cupronickel.

However, the allowable range of impurities mentioned above varies considerably depending on the alloy, and cannot be used interchangeably.

[Problems to be Solved by the Invention] The present invention solves the problem that conventional copper alloys for terminals and lead frames have poor hot workability. This was made for the purpose of providing a copper alloy for terminals and lead frames that also has characteristics as a copper alloy for use in copper alloys.

[Means for Solving the Problems] The present invention provides copper alloys for terminals and lead frames with excellent hot workability, including Ni: 2.0 to 3.5 wt%, Si
: 0.5-0.9wt%, Mn: 0.01-1.0
wt%, Zn: 0. 1-5. 0wt%, Sn
: 0.1~2. Owt%, Mg: 0.001-0.
In a copper alloy containing 0.01 wt% and further containing o, ooi to 0.01 wt% of one or more of Cr, Ti, and Zr, the impurity content of the copper alloy is P
b: 0.002wt% or less, Bi: 0.001wt%
Below, Sho, 001wt% or less, Sb: 0.001w
t% or less, Te: 0.001wt% or less, Se: 0.0
005wt% or less, Se: 0.0005wt% or less is the gist of Kano 1, and the second gist is that in the above copper alloy manufacturing method, hot rolling is started at 700 to 850 ° C. do.

[Function] The reason for limiting the additive elements of the alloy of the present invention and the function will be explained below.

Ni is an element that strengthens the alloy together with St, and if its content is less than 2.0 wt%, the strength and heat resistance will not improve even if St is contained at 0.5 to 0.9 wt%, and 3.5 wt%
If it exceeds 2.0 to 3.5 wt%, the conductivity decreases.
shall be.

Si strengthens the alloy together with Ni, but its content is 0.
If it is less than 5 wt%, the strength and heat resistance will not improve even if Ni is contained in 2.0 to 3.5 wt%, and if it exceeds 0.9 wt%, the conductivity will decrease, so the Ni content should be 0.5 to 0.9 wt%. .

Sn is an element that contributes to improving strength, repeated bendability, stiffness strength, and spring limit value, and if its content is less than 0.1 wt%, it will not have these effects, and 2. o
If it exceeds wt%, the conductivity decreases, so 0.1 to 2.0
Let it be wt%.

Mn is an element that improves hot workability, and if its content is less than 0.002 wt%, no effect will be seen.
．． If it exceeds 0 wt%, the yield during agglomeration will decrease and the conductivity will also decrease, so the content is set at 0.02 to 1.0 wt%.

Zn is an element that significantly improves the heat peeling properties of plated tin and solder, and its content is 0.1 wt%.
If it is less than 5.0 wt%, this effect will be small, and if it exceeds 5.0 wt%, the solderability will deteriorate, so the range is set to 0.1 to 5.0 wt%.

Mg is an element that fixes S in the alloy as a stable Mg compound and provides hot workability. If its content is less than 0.001 wt%, S cannot be fixed as a stable Mg compound. , if it exceeds 0.01 wt%, the drying properties of the molten metal will deteriorate and the agglomeration yield will decrease, so 0.0
01 to 0.01 wt%.

Cr, Ti, and Zr are elements that improve hot workability.
The content is 0.001wt% alone or in combination of two or more
If it is less than 0.01 wt%, this effect will be small, and if it exceeds 0.01 wt%, drainage properties will deteriorate and the agglomeration yield will decrease.
001 to 0.01 wt%.

In the present invention, in order to prevent hot cracking caused by impurities, Pb, Bi, and S are added as shown in Table 1.

An alloy containing Sb, Te, Te, and Se as impurities was formed into an ingot, and a melt test was conducted to investigate the allowable amount thereof.

As a result, to prevent cracking and ensure hot workability,
It was clarified that the above impurities must be limited as follows. That is, Pb: 0.002wt% or less, Bi: 0.001wt% or less, Sho, 001wt
% or less, Sb: 0.001wt% or less, Te: 0.00
1wt% or less, Se: 0.0005wt% or less, Se:
The content shall be 0.0005wt% or less.

Moreover, in the manufacturing process of the copper alloy of the present invention, it is necessary to set the hot rolling start temperature to 700 to 850°C.

That is, if the hot rolling start temperature exceeds 850°C, intergranular cracking will occur at the early stage of hot rolling, so it must be 850°C or lower. Furthermore, if the temperature is below 700°C, intergranular cracking will still occur at the early stage of hot rolling, so the temperature must be above 700°C.

[Example] EXAMPLES The present invention will be specifically described below with reference to Examples.

(Example 1) An alloy having the composition shown in Table 1 was melted in a Kributorumi air furnace and cast into a book mold of 50 mm x 50 mm x 200 mm.
A mm ingot was produced.

A test piece of 15 mmφ x 15 mmH was prepared from the ingot, heated to a temperature of 600 to 950 t, and subjected to a melt electrode test up to 9 mmH, and hot workability was determined based on the number of cracks.

In Table 1, No. 1 to No. to are Examples of the present invention, and no cracking occurred in the melt electrode test.

No. 11 to No. 21 are comparative examples, and as a result of the electrode test, cracks occurred.

FIG. 1 is a diagram showing the relationship between the Pb content and the number of cracks, and FIG. 2 is a diagram showing the relationship between the Bi content and the number of cracks.

As shown in FIGS. 1 and 2 above, if the impurity content is within the range of the present invention, no cracking will occur.

(Example 2) No. 3 of Example 1. No, 4. No, 11°No, 1
A test piece of an alloy having the same composition as No. 2 was prepared and a melt test was conducted.

The results are shown in Figure 3.

As shown in FIG. 3, test pieces with a Pb content of 20 ppm or less do not crack at temperatures of 700 to 850° C. and have good workability.

However, cracks occur when the Pb content exceeds 20 ppm.

(Example 3) An alloy having the composition shown in Table 2 was continuously cast to form a 140mmt
X470mmwx4000mmj! Create an ingot of 8
Hot working was performed at 25-835°C.

Although Example Nos. 22 to 24 showed excellent hot rolling properties, Comparative Example No. 25. In No. 26,
The Pb content exceeded 0.002 wt%, and cracks occurred in the ingot ears and rolling surface.

[Effects of the Invention] According to the present invention, steel alloys for terminals and lead frames can be manufactured with high productivity without cracking during hot working.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the Pb content and the number of cracks, and FIG. 2 is a graph showing the relationship between the Bi content and the number of cracks. Further, FIG. 3 is a graph showing the melt electrode test temperature and the number of cracks generated for alloys with different Pb contents. Figure 1 PB content i (ppm)

Claims (2)

[Claims] (1) Ni: 2.0-3.5wt%, Si: 0.5-0
．． 9wt%, Mn: 0.01-1.0wt%, Zn: 0
．． 1 to 5.0 wt%, Sn: 0.1 to 2.0 wt%, M
g: 0.001 to 0.01 wt%, and further contains C
0.00 of one or more of r, Ti, and Zr
In a copper alloy containing 1 to 0.01 wt%, the impurity content of the copper alloy is Pb: 0.002 wt% or less, B
i: 0.001wt% or less, S: 0.001wt% or less, Sb: 0.001wt% or less, As: 0.001wt
% or less, Te: 0.0005wt% or less, Se: 0.0
A copper alloy for terminals and lead frames, characterized by having a content of 0.005 wt% or less and excellent hot workability. (2) Ni: 2.0-3.5wt%, Si: 0.5-0
．． 9wt%, Mn: 0.01-1.0wt%, Zn: 0
．． 1-5.0wt%, Mg: 0.001-0.01wt
%, and further contains 0.001 to 0.01 wt% of one or more of Cr, Ti, and Zn, and further has an impurity content of Pb: 0.002 wt% or less, Bi:
0.001wt% or less, S: 0.001wt% or less, S
b: 0.001 wt% or less, As: 0.001 wt% or less, Te: 0.0005 wt% or less, Be: 0.000
A method for producing a copper alloy for terminals and lead frames having excellent hot workability, the method comprising starting hot rolling of a copper alloy having a content of 5 wt% or less at 700 to 850°C.