JPH09316569A - Copper alloy for lead frame and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive copper alloy for lead frame, excellent in mechanical strength, electric conductivity, heat resistance, and direct bonding property and suitable for use as lead frame material, and its production. SOLUTION: The copper alloy for lead frame is a copper alloy, having a composition consisting of, by weight ratio, 0.05-0.3% Ag, 0.05-0.3% Cr, <0.0010% P, <0.0010% Sn, and the balance essentially Cu with inevitable impurities, and a copper alloy having a composition further containing, besides the above components, 0.01-0.3%, in total, of one or >=2 elements selected among Zn, Ni, Mg, Zr, Ti, and Al. The copper alloy for lead frame can be produced by subjecting these copper alloys, in succession, to casting, hot rolling, cold working, heating treatment at 850-1000 deg.C for >=600sec, rapid cooling with water, holding at 400-700 deg.C for 2-6hr, cold rolling at >=70%, and then final heat treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame copper alloy suitable as a lead frame material and a method for producing the same.

[0002]

2. Description of the Related Art Copper alloys such as oxygen-free copper, Sn-containing copper, and Fe-containing copper are widely known as conventional copper alloys for lead frames.

In recent years, with the reduction in size and weight of electronic equipment, such lead frame materials are required not only to have excellent mechanical strength but also to have the following characteristics. (1) Excellent electrical and thermal conductivity. (2) Excellent softening resistance. (3) Excellent moldability. (4) Excellent direct bonding property. However, it cannot be said that various conventional copper alloys sufficiently satisfy such characteristics.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a lead frame copper alloy having the above-mentioned excellent moldability, conductivity, heat resistance, and direct bonding properties required for a lead frame material, and the same. Propose a manufacturing method.

[0005]

[Means for Solving the Problems] The first invention is A by weight ratio.
g; 0.05 to 0.3%, Cr; 0.05 to 0.3%,
P: less than 0.0010%, including Sn: 0.0010,
A copper alloy for a lead frame, characterized in that the balance substantially consists of Cu and inevitable impurities,

The second aspect of the present invention is Ag: 0.05-by weight.
0.3%, Cr; 0.05 to 0.3%, P; 0.001
Less than 0%, Sn; including less than 0.0010%, Zn, N
One or two or more selected from i, Mg, Zr, Ti, and Al are contained in a total amount of 0.01 to 0.3%, and the balance is substantially composed of Cu and inevitable impurities. Is a copper alloy for lead frames,

In the third invention, the weight ratio of Ag is from 0.05 to
0.3%, Cr; 0.05 to 0.3%, P; 0.001
Less than 0%, Sn; less than 0.0010%, the balance being substantially Cu and unavoidable impurities, and after casting, hot-rolling and cold-working, then 600 seconds at 850 to 1000 ° C. After the above heat treatment and quenching with water, 400-70
A method for producing a copper alloy for a lead frame, which is characterized by holding in a temperature range of 0 ° C. for 2 to 6 hours, then performing 70% or more cold rolling, and performing a final heat treatment,

The fourth aspect of the present invention is, by weight ratio, Ag;
0.3%, Cr; 0.05 to 0.3%, P; 0.001
Less than 0%, Sn; including less than 0.0010%, Zn, N
A copper alloy containing 0.01 to 0.3% in total of one kind or two kinds or more selected from i, Mg, Zr, Ti and Al, and the balance substantially consisting of Cu and inevitable impurities. After casting, after hot rolling and cold working, 850-100
After heat treatment at 0 ℃ for 600 seconds or more and quenching with water, 400
Hold at temperature range of ~ 700 ° C for 2 ~ 6 hours, then 70
% Of cold rolling and final heat treatment are provided.

The present invention is a copper alloy having the above-mentioned structure, is excellent in conductivity, heat resistance, formability and direct bonding property, and is suitable as a lead frame material.

Next, the reason for adding the alloy components constituting the alloy of the present invention and the reason for limiting the addition will be explained. Ag from 0.05 to
0.3 wt% means that Cu is Cu even if it is in a solid solution state.
Is an additive element that enhances the strength without lowering the conductivity.
If it exceeds 3 wt%, the effect is saturated and the cost is increased, so that it is not industrial.

[0011] Cr is an additive element that enhances heat resistance and mechanical strength without lowering the conductivity of Cu due to the precipitation effect.
If it exceeds 3 wt%, the castability and the conductivity are inevitably deteriorated.

The reason why Sn is less than 0.0010 wt% is that when it exceeds 0.001 wt%, the conductivity of Cu is lowered and the direct bonding property is adversely affected.

The reason why P is less than 0.0010 wt% is that
This is because if it exceeds 0.001 wt%, the direct bondability is adversely affected.

Zn, Ni, Mg, Zr, Ti, Al
The addition of one or more of these elements can improve the mechanical strength without significantly reducing the conductivity, and if the addition amount is less than 0.01 wt%, the effect is small. This is because if it exceeds 0.3 wt%, the conductivity will be greatly reduced.

In the present invention, the copper alloy having the composition range according to the first invention and the second invention is 600 at 850 to 1000 ° C.
The heating for at least 2 seconds is for eliminating the precipitates generated during the production and for forming a uniform solid solution in the Cu matrix. At a heating temperature of 850 ° C or lower, the effect is insufficient, and at 1000 ° C or higher, the material Some may dissolve. The reason why it is held for 600 seconds or more is that the above effect cannot be obtained if the time is less than 600 seconds.

The heat treatment at 400 to 700 ° C. is for uniformly precipitating Cr which has been once made into a solid solution.
This is because the precipitation is not sufficiently promoted at a temperature of not higher than 0 ° C, whereas the precipitate becomes coarse at a temperature of not lower than 700 ° C. The holding time was set to 2 to 6 hours because sufficient precipitation is not promoted when the time is 2 hours or less, while the precipitate becomes coarse when the time is 6 hours or more.

The cold working of 70% or more is to improve the mechanical strength. The final heat treatment is intended to reduce the strain generated in the cold working and to recover the elongation. Next, an embodiment of the present invention will be described.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1 FIG. 1 is a schematic explanatory view showing a process for producing an alloy test piece according to the present invention, and alloys (Nos. 1 to 3 and N having the composition shown in Table 1
o. No. 7 is the first invention, and No. 7 is. 40 mm (width) x 1 by melting in a high frequency vacuum melting furnace so that 4 to 6 are the second invention).
It was cast into an ingot of 00 mm (length) × 10 mm (thickness). After hot rolling at 900 ° C. to form a plate with a thickness of 10 mm and performing cold working, 600 at 850 to 1000 ° C.
After heat treatment (primary) for more than 2 seconds, it was quenched with water.

Then, in the temperature range of 400 to 700 ° C., 2
After holding for 6 hours to perform heat treatment (secondary), 70% or more cold rolling was performed and final heat treatment was performed as a plate having a thickness of 0.25 mm.

As the evaluation of the sample thus prepared, the mechanical strength is a tensile test, the elongation is a JIS No. 5 test piece,
The hardness is measured by a Vickers hardness meter, and the softening resistance is the temperature at which the hardness after heating for 7 minutes becomes 80% of the hardness after rolling,
Conductivity and heat conductivity are conductivity (% IACS), and direct bondability is evaluated by conducting a tensile test with a load of 5 g after direct bonding of an Au wire and peeling. Those marked and peeled were marked with X. Table 1 shows the results.

[0021]

[Table 1]

The comparative materials in Table 1 are out of the composition ranges defined in the first and second inventions according to the present invention,
For example, no. No. 8 is P. No. 9 is Sn, 10
Is Ag, No. No. 11 is Cr, No. 12 is Ag, P, N
o. No. 13 is Ag, P, Sn, No. 14 is Cr and P,
No. No. 15 contains Ag and other components, and No. In No. 16, the other components are outside the range of the component composition of the present invention.

As shown in Table 1, the alloy according to the present invention is
It is clear that it has sufficient mechanical strength, electrical conductivity, heat resistance, and direct bonding property, and it is found that it is suitable as a material for electric / electronic devices requiring high reliability, particularly as a lead frame material.

Example 2 In the method for producing an alloy within the alloy composition range according to the present invention,
A production comparison test was conducted when the production conditions were within or outside the conditions specified by the third invention and the fourth invention. The results are shown in Table 2.

[0025]

[Table 2]

In Table 2, the alloy composition is No. 17 and N
o. No. 22 in Table 1 is No. No. 3, 18 and No.
No. 23 in Table 1 is No. 23. No. 4 19 and No. 24
And No. in Table 1. 5, No. 5 20 and No. No. 25 in Table 1 is No. 25. 6 has the same composition as the composition of
This is especially the case when the primary heat treatment conditions are changed. The manufacturing process of the test piece is as shown in FIG.

As can be seen from Table 2, in the composition range defined in the present invention, the manufacturing conditions are also within the specified conditions. 1
The mechanical strength, conductivity, heat resistance, and direct bondability of Nos. 7, 18, 19, and 20 of Example 1 (shown in Table 1) were also obtained. Nos. 3, 4 and 5 and 6 show excellent characteristics, but different primary heat treatment conditions. 22, 25,
No. 2 with different secondary heating conditions. The alloys 23 and 24 are particularly inferior in conductivity and direct bonding property.

[0028]

As can be seen from the above examples, the copper alloy according to the present invention and the method for producing the same are excellent in formability, mechanical strength, conductivity, heat resistance and direct bonding and have high reliability. It is suitable as a required electric / electronic device member, especially as a lead frame material.

Further, the alloy of the present invention is extremely easy to melt, hot-roll, cold-roll, and intermediate heat treatment, and has no technical difficulty at all, and requires a special heat treatment or a complicated process. It is easier and cheaper to manufacture than the base alloy.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a process of producing an alloy test piece according to the present invention.

Claims (4)

[Claims] 1. Ag by weight ratio: 0.05 to 0.3%, C
r: 0.05 to 0.3%, P: less than 0.0010%, S
n: less than 0.0010%, the balance substantially consisting of Cu and unavoidable impurities, copper alloy for lead frames. 2. A weight ratio of Ag; 0.05 to 0.3%, C
r: 0.05 to 0.3%, P: less than 0.0010%, S
n: containing less than 0.0010%, Zn, Ni, Mg, Z
It contains 0.01 to 0.3% in total of one or more selected from r, Ti and Al, and the balance is substantially C
A copper alloy for a lead frame, which comprises u and unavoidable impurities. 3. Ag by weight ratio; 0.05 to 0.3%, C
r: 0.05 to 0.3%, P: less than 0.0010%, S
n; a copper alloy containing less than 0.0010% and the balance substantially consisting of Cu and inevitable impurities is hot-rolled after casting,
After cold working, heat treatment at 850 to 1000 ° C. for 600 seconds or more, quenching with water, holding in the temperature range of 400 to 700 ° C. for 2 to 6 hours, and then 70% or more cold rolling. A method of manufacturing a copper alloy for a lead frame, which is performed and then subjected to a final heat treatment. 4. Ag by weight ratio; 0.05-0.3%, C
r: 0.05 to 0.3%, P: less than 0.0010%, S
n: containing less than 0.0010%, Zn, Ni, Mg, Z
It contains 0.01 to 0.3% in total of one or more selected from r, Ti and Al, and the balance is substantially C
After casting a copper alloy consisting of u and unavoidable impurities, hot rolling and cold working, then 600 at 850 to 1000 ° C.
After heat treatment for more than 2 seconds and quenching with water, 400-700 ℃
In the temperature range of 2 to 6 hours, and then 70% or more of cold rolling is performed for final heat treatment.