JPH0718356A - Copper alloy for electronic equipment, its production and ic lead frame - Google Patents

Abstract

PURPOSE:To produce an excellent copper alloy for electronic equipment having excellent characteristics of both strength and electric conductivity and satisfying performance required for the recent material for electronic equipment and to provide a method for producing the same. CONSTITUTION:This copper alloy for electronic equipment is the one contg., by weight, 1.0 to 3.0% Ni, 0.06 to 0.5% Si, 0.05 to 0.5% P and 1.0 to 3.0% Zn, suitably contg. at least one or more kinds selected from the group of Sn, Cr, Mg, Mn, Co, Ti, Zr, Ag, B and Fe, and the balance copper, and in which the content of N2 is regulated to <=50ppm, H2 to <=30ppm and O2 to <=20ppm. This alloy is produced by executing a stage of rolling before final finish, heating it in the temp. range of 750 to 950 deg.C for >=1min and rapidly cooling it in water or oil and a stage of subjecting it to the subsequent heating in the temp. range of 350 to 500 deg.C for >=10min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy for electronic equipment used in lead frame materials for integrated circuits (ICs), connectors, switches, relays, etc., and a method for manufacturing the same.

[0002]

2. Description of the Related Art As materials used in electronic equipment, in addition to high strength and high electrical conductivity, materials having more excellent corrosion resistance and heat resistance have been demanded along with the demand for miniaturization of parts and high reliability. .
Conventional copper alloys for electronic devices include CDA (Copper)
Develoment Association) C19400 alloy,
Highly conductive alloys such as Cu-0.1% Sn and Cu-0.1% Fe or high strength alloys such as phosphor bronze have been mainly used. Further, as the copper alloy for the lead frame, for example, JP-A-2-205642 and JP-A-2-205642.
As a method for producing a copper alloy for a lead frame, which is proposed in Japanese Patent Publication No. 205645, etc., for example, Japanese Patent Publication No. 60-5878.
It is proposed in Japanese Patent No. 3, etc.

[0003]

However, the above-mentioned C
Conventional alloys such as DAC19400 alloy still have a problem that they cannot have high strength and high electrical conductivity together with the demand for miniaturization and high reliability of materials used for electronic devices. In addition, a proposal has been made to simply limit the oxygen content in order to improve the reliability of solderability and plating adhesion, but this alone is not sufficient for ensuring the above reliability. The present invention has excellent properties in both mechanical strength and electrical conductivity, and an object thereof is to provide an excellent copper alloy for electronic devices and a method for producing the same, which satisfies the performance required for materials for recent electronic devices. To do.

[0004]

As a result of earnest studies, the present inventors were able to solve the above-mentioned conventional problems. In the following description, unless otherwise specified,
% Is on a weight basis.

That is, the present invention provides (1) Ni 1.0 to 3.
0%, Si 0.06 to 0.5%, P 0.05 to 0.5%, Z
containing N1.0～3.0%, the balance being copper and inevitable impurities, wherein the N ₂ content, 50 ppm or less, H ₂ content of 30ppm or less and O ₂ content is 20ppm or less The present invention provides a copper alloy for electronic devices.

The present invention also provides (2) Ni 1.0-3.0.
%, Si 0.06 to 0.5%, P 0.05 to 0.5%, Zn
1.0 to 3.0%, and Sn and C as secondary components
r, Mg, Mn, Co, Ti, Zr, Ag, B and F
containing at least one or two or more kinds selected from the group consisting of e in a total amount of 0.001 to 0.3%, the balance consisting of copper and inevitable impurities, and having an N ₂ content of 50 ppm.
Hereinafter, the H ₂ content is 30 ppm or less and the O ₂ content is 2
The present invention provides a copper alloy for electronic devices, which is characterized by being 0 ppm or less.

Further, according to the present invention, (3) the grain size is 20 μm.
The copper alloy for electronic devices according to the above (1) or (2), characterized in that the copper alloy has a thickness of m or less.

Furthermore, the present invention (4) is characterized in that there is a precipitate by aging treatment, and the size of the precipitate is 2 μm or less, any one of the above (1) to (3)
And a copper alloy for electronic devices.

The present invention also provides (4) a temperature range of 750 to 950 ° C. before the final finish rolling of the ingot of the copper alloy for electronic devices in which the components described in (1) or (2) are added and melted. Of a copper alloy strip for electronic equipment, characterized by performing a step of heating for 1 minute or more in water and quenching in water or oil, and then performing a step of heating in a temperature range of 350 to 500 ° C. for 10 minutes or more. It provides a method.

Further, the present invention is (6) above (1) or (2)
In the temperature range of 750 to 950 ° C., before the final finish rolling of the ingot of the copper alloy for electronic devices in which the components described in 1) are added and melted
The present invention provides a method for producing a copper alloy strip for electronic devices, which comprises heating for at least 1 minute and then gradually cooling at 4 ° C / minute or less.

The present invention also provides (7) the above (1) or
Before the final finish rolling of the ingot of the copper alloy for electronic devices in which the components described in (2) are added and melted, after heating for 1 minute or more in the temperature range of 750 to 950 ° C, up to 500 ° C, 4 ° C / minute The present invention provides a method for producing a copper alloy strip for electronic devices, which comprises cooling as described above and holding or gradually cooling at a temperature of 500 to 350 ° C. for at least 1 hour or more.

The present invention also provides (8) an IC lead frame using the copper alloy for electronic devices according to any one of (1) to (4) above.

[0013]

Next, the reason for adding the alloy components constituting the copper alloy for electronic equipment of the present invention and the reason for limiting the composition range will be described. Ni, P and Si have these elements as Ni ₅ P.
The lower limit of Ni is 1. In the range where intermetallic compounds such as ₂ and Ni ₂ Si are efficiently generated, and the strength is improved and the conductivity is not lowered.
If it is less than 0%, the amount of intermetallic compounds is small and the strength is not improved so much. If it exceeds 3%, the improvement of the strength level is less effective than the compounding amount, and the workability is deteriorated. At the same time, the electric conductivity tends to decrease and the heat resistance of the solder plating tends to deteriorate. In order to efficiently generate the intermetallic compound of Ni and P and Ni and Si, the strength and the electric property should be set when the weight ratio of Ni: P is about 5: 1 and Ni: Si is about 4: 1. It has the highest level of conductivity, which is an intermetallic compound such as Ni ₅ P ₂ or Ni _2.
It is almost equivalent to Si. Therefore, the amounts of P and Si are determined by this weight ratio. Zn has an effect of improving heat resistance against peeling of plating, and if the lower limit is less than 1%, the effect is small, and if it exceeds the upper limit of 3%, the solderability is deteriorated and the electrical conductivity is lowered. This range was set.

Sn, Co, and Mg added as subcomponents are intended to improve the strength by solid solution in the base material. If at least one kind or two or more kinds are added by 0.001% or more, the tensile strength is improved. , If 0.3% is exceeded, the conductivity will decrease.

Cr, Ti and Z added as auxiliary components
r and Fe are at least one kind or two or more kinds and 0.001%
If added in the above amount, the heat resistance is improved, but if it exceeds 0.3%, it becomes undissolved and easily dispersed in the grain boundaries, and the reliability such as plating adhesion is deteriorated.

Further, when 0.001% or more of Ag is added as a sub ingredient, the heat resistance reliability of the plating is improved, but
If it exceeds 3%, the effect corresponding to the added amount cannot be obtained, and the cost only increases.

Alternatively, if at least one of Mn and B is added as an accessory component in an amount of 0.001% or more, the content of O ₂ as a deoxidizer can be reduced, and solderability and plating adhesion can be improved. If it exceeds 0.3%, the conductivity decreases.

[0018]

EXAMPLES The present invention will be described below with reference to examples. Example 1. After adding each compositional component shown in (Table 1), melting and casting, cold rolling and heat treatment were repeated, and finally the thickness was reduced to 0.
A 4 mm plate was finished, and the following processing was then performed to confirm the characteristics. In addition, the ingot processing method according to Table 1 is as follows.
It depends on the process.

(Process A) 0.4 mm plate → quenched (800 ° C. ×
3 minutes, quenching in water) → aging treatment (450 ° C x 2 hours) →
Rolled 0.25 mm plate.

In (Table 1), the electric conductivity was measured by measuring the electric resistance of the sample, and the electric conductivity (% IAC) was obtained.
It is indicated by S). In addition, plating heat resistance means that after soldering to the 0.25 mm plate after rolling, it is held at a high temperature of 150 ° C., and then the soldered part is subjected to close contact bending,
The time until peeling or the like occurs was measured and evaluated. In addition, in FIG. 1 and FIG. 2, the relationship between the tensile strength and the electric conductivity is shown. The range indicated by the shaded area is the target characteristic, and the electric conductivity is 38% or more and the heat treatment is performed in consideration of the balance with the tensile strength. The range was determined.

From the results of (Table 1), (No. 1), (No. 9), (N
Comparing each sample of o.5) and (No. 13), it can be seen that the tensile strength decreases when Ni is less than 1.0%, and the conductivity decreases when Ni exceeds 3.0%.

Further, comparing (No. 2) and (No. 10) and (No. 6) and (No. 14) samples, when P is less than 0.05%, the tensile strength and the conductivity decrease. However, even if P exceeds 0.5%, the tensile strength and the conductivity decrease.

Further, (No.3) and (No.11), (No.7) and (No.15)
Comparing each of the above samples, it can be seen that when Si is less than 0.06%, the tensile strength and the conductivity decrease, and when Si exceeds 0.5%, the conductivity decreases. Furthermore, (No.4) and (No1
Comparing (2), (No. 8) and (No. 16), it can be seen that the plating heat resistance is poor when Zn is less than 1.0% and the conductivity is reduced when Zn is more than 3.0%.

In (No. 18), N ₂ is 55 ppm, and (No. 1)
35 ppm of H ₂ in 7) and 30 pp of O _{2 in} (No. 19)
When m and the remaining amount are large, the plating heat resistance is reduced. In particular, when the sample is heated at 350 ° C. for 10 minutes after silver plating, blisters are generated in the plated portion, and reduction in plating heat resistance is recognized.

Further, as shown in (No. 20) and (No. 21), when Sn and Co added as auxiliary components, the tensile strength is improved when the total amount thereof reaches 0.4%, but the conductivity is increased. It can be seen that the plating heat resistance decreases.

Further, as shown in (No. 22) and (No. 23), the total amount of Sn and Mg added as auxiliary components is 0.4.
It can be seen that when the content reaches 100%, the tensile strength is improved, but the electrical conductivity and plating heat resistance are reduced.

As shown in (No. 24) and (No. 29), when Cr and Ti added as auxiliary components reach a total content of 0.4%, the tensile strength is improved, but the conductivity, The plating heat resistance decreases.

As shown in (No.25) and (No.28), when Cr and Zr added as auxiliary components reach a total content of 0.4%, the tensile strength is improved, but the conductivity, The plating heat resistance decreases. As shown in (No.27) and (No.37), when Cr and Fe added as subcomponents reach a total content of 0.4%, the tensile strength improves, but the electrical conductivity and plating heat resistance are improved. Sex decreases.

As shown in (No.30) and (No.31), when Ag is added as an accessory component, the plating heat resistance is improved but the conductivity is lowered when the added amount reaches 0.4%.

As shown in (No. 32), (No. 33) and (No. 38), the content of O ₂ is reduced as compared with the case where Mn and B added as accessory components are not added. However, when the total addition amount reaches 0.4%, the conductivity decreases.

FIG. 2 is a plot of electrical conductivity and tensile strength in each of the examples and comparative examples shown in Table 1. From FIG. 2, it can be seen that the examples of the present invention are superior to the comparative examples in both conductivity and tensile strength.

[0032]

[Table 1]

[0033]

[Table 2]

Example 2. Example 1 above is 800 ° C. × 3
This is the case of each composition component that has been subjected to an aging treatment at 450 ° C. for 2 hours after quenching in water for 1 minute, but in Example 2 of FIG.
As shown in, the quenching temperature and the aging temperature were changed, and the electrical conductivity and tensile strength of each composition component were measured.
As a result, it can be seen that optimum properties can be obtained with respect to tensile strength and conductivity within a range of 750 to 950 ° C. for quenching temperature and 350 to 500 ° C. for aging treatment temperature. The heating at the time of quenching is preferably 750 to 950 ° C. for 1 minute or more, and the aging treatment is preferably performed for 10 minutes or more. The cooling medium in the quenching may be a usual cooling medium, and examples thereof include water and oil.

Further referring to FIG. 1, 750-95
It can be seen that the crystal grain size corresponding to the quenching temperature of 0 ° C. is also 20 μm or less. At this time, if the quenching temperature is less than 750 ° C., recrystallization is insufficient, and if it exceeds 950 ° C., the crystal grain size becomes coarse, and the surface of the material tends to be rough during bending. If the aging temperature is less than 350 ° C, the precipitation of intermetallic compounds will be insufficient, and the tensile strength and the conductivity will both decrease, and
If it exceeds 00 ° C, it softens and the tensile strength decreases.

Example 3. Table 2 shows the case where the plate material processed to 0.4 mm in each composition of Example 1 in (Table 1) was annealed and rolled, and the annealing conditions were changed to a plate material of 0.25 mm. It shows the measurement results of tensile strength and conductivity.

As can be seen by comparing the categories a to c, for example, after heating at 800 ° C. for 2 hours and gradually cooling at 4 ° C./min or less before the final rolling finish, the tensile strength and the conductivity are suitable. It can be seen that the characteristics can be obtained. Also, as you can see by comparing the categories d to 800 ° C, for example
After heating for 2 hours at 500 ° C., cooling to 4 ° C./min or more up to 500 ° C. and holding for 1 hour or more between 500 ° C. and 350 ° C., appropriate properties for tensile strength and conductivity are obtained as described above. I understand.

[0038]

[Table 3]

It goes without saying that the copper alloy for electronic devices having the characteristics described above has the optimum characteristics as an IC lead frame.

[0040]

As is clear from the above examples, according to the present invention, it has excellent characteristics in both strength and electrical conductivity,
Since an excellent copper alloy for electronic devices and a method for producing the same that satisfy the performance required for recent electronic device materials are provided, they are very useful for downsizing of electronic device parts.

[Brief description of drawings]

FIG. 1 is a characteristic diagram when a aging temperature and a quenching temperature of a copper alloy according to an embodiment of the present invention are changed.

FIG. 2 is a diagram showing the tensile strength and the electrical conductivity of the copper alloy obtained in step A of the method of the present invention and the copper alloy obtained in the comparative example.

Claims (8)

[Claims] 1. Ni 1.0 to 3.0% by weight, Si 0.06
~ 0.5 wt%, P0.05-0.5 wt%, Zn1.0-
3.0% by weight, the balance consisting of copper and unavoidable impurities, N ₂ content of 50 ppm or less, H ₂ content of 3
A copper alloy for electronic devices, which is 0 ppm or less and has an O ₂ content of 20 ppm or less. 2. Ni 1.0 to 3.0% by weight, Si 0.06
~ 0.5 wt%, P0.05-0.5 wt%, Zn1.0-
It contains 3.0% by weight, and Sn, Cr, and
It contains at least one or two or more kinds selected from the group consisting of Mg, Mn, Co, Ti, Zr, Ag, B and Fe in a total amount of 0.001 to 0.3% by weight, and the balance copper and unavoidable. Containing impurities, N ₂ content of 50ppm
Hereinafter, the H ₂ content is 30 ppm or less and the O ₂ content is 2
Copper alloy for electronic devices, which is 0 ppm or less. 3. The copper alloy for electronic devices according to claim 1, wherein the crystal grain size is 20 μm or less. 4. The copper alloy for electronic devices according to claim 1, wherein precipitates due to aging treatment are present and the size of the precipitates is 2 μm or less. 5. Before final finishing rolling of an ingot of a copper alloy for electronic devices, in which the component according to claim 1 or 2 is added and melted,
An electronic device characterized by performing a step of heating in a temperature range of 750 to 950 ° C for 1 minute or more and quenching in water or oil, and a step of heating in a temperature range of 350 to 500 ° C for 10 minutes or more. Manufacturing method of copper alloy strip for equipment. 6. The final ingot rolling of the ingot of the copper alloy for electronic devices in which the component according to claim 1 or 2 is added and melted.
A method for producing a copper alloy strip for electronic devices, which comprises heating in a temperature range of 50 to 950 ° C. for 1 minute or more, and then gradually cooling at 4 ° C./minute or less. 7. Before final finishing rolling of an ingot of a copper alloy for electronic devices, in which the component according to claim 1 or 2 is added and melted.
After heating in the temperature range of 50 to 950 ° C for 1 minute or more, 5
Cool at 4 ℃ / min or more up to 00 ℃, 500-350 ℃
The method for producing a copper alloy strip for electronic devices, characterized by holding or gradually cooling for at least 1 hour or more. 8. An IC lead frame using the copper alloy for electronic devices according to any one of claims 1 to 4.