JPH10152736A - Copper alloy material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copper alloy having high strength and high electric conductivity. SOLUTION: A copper alloy, having a composition in which 2.5wt.% Ni, 0.5wt.% Si, 0.5wt.% Zn, and 0.3wt.% P are added to Cu and the value of Ni/Si, by weight, is regulated to 4.5-5.5, is used. First, after heating to 850 deg.C and hot extrusion, cold rolling is performed (step 102). Subsequently, after heating to 800 deg.C, rapid cooling is performed to carry out solution heat treatment (step 103), and then cold rolling is done at 20-80% draft (step 104). Further, primary aging treatment is applied at 450 deg.C for 1hr (step 105), cold rolling is performed at 10-70% draft (step 106), and then secondary aging treatment is is carried out at 420 deg.C for 1hr. By this method, the copper alloy, having high strength and high electric conductivity, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy used for electronic equipment, particularly to a copper alloy material having high strength and high thermal conductivity, and a method for producing the same.

[0002]

2. Description of the Related Art Metallic materials for electronic devices have strength, heat resistance, workability for punching and processing, heat conductivity capable of releasing generated heat to the outside, plating property, In addition to properties such as solderability and corrosion resistance,
Low prices are required. For example, in a lead frame used for a semiconductor device, miniaturization of an element
The characteristics corresponding to high integration, that is, the higher the strength and the higher the amount of heat generated in response to the thinning of the material, the higher the thermal conductivity and conductivity that can secure sufficient heat dissipation. There is a need for the development of materials with these.

[0003] Materials that can meet such demands include:
High-purity copper alloy materials have attracted attention, and various materials have been developed. Among them, an alloy based on a Cu-Ni-Si alloy (Corson alloy) is expected to have a high tensile strength of 700 MPa, and is therefore promising. This Cu-Ni-Si alloy is a precipitation hardening type alloy. Usually, a liquefaction process of rapidly cooling from a high temperature of about 800 ° C.
The alloy element is precipitated in the Cu matrix in the form of a Ni ₂ Si compound by aging treatment by heating to about 500 to 500 ° C., and the strength is improved by making it an obstacle to dislocation movement. In addition, since the alloy element is positively precipitated, the thermal conductivity and the electrical conductivity are easily maintained better than the alloy in the solid solution state.

[0004]

However, Cu-Ni-
According to the Si alloy, when a production process using a normal simple solution treatment and aging treatment is employed for the production, although a high tensile strength of 700 MPa is obtained in terms of strength,
The conductivity remains at the level of 30-40% IACS. This conductivity remains unsatisfactory for use in a lead frame of a semiconductor device using a QFP (Quad Fiat Package).
The reason why the electrical conductivity does not increase as described above is that the amount of alloying elements remaining in a solid solution state without being completely precipitated is large.
Therefore, in order to cause sufficient precipitation, when the aging treatment temperature is raised or the treatment time is lengthened, the conductivity is improved, but on the contrary, the precipitate becomes coarse and the strength is reduced. .

Accordingly, an object of the present invention is to provide a copper alloy material having both high strength and high electrical conductivity, and a method for producing the same.

[0006]

In order to achieve the above-mentioned object, the present invention relates to a method for producing Ni of 1.0 to 5.0 wt% in which the weight ratio of Ni / Si is 4.5 to 5.5, and 0.1. 2-1.0w
t% of Si, 0.3 to 5.0 wt% of Zn, and 0.1% of Zn.
It is characterized by containing 003 to 0.3 wt% of P, having a predetermined solution treatment, a cold rolling, and an aging treatment to have a conductivity of 50% IACS or more and a tensile strength of 700 MPa or more. The present invention provides a copper alloy material.

[0007] To achieve the above object, the present invention provides:
The weight ratio Ni / Si was adjusted to 4.5 to 5.5.
0 wt% Ni and 0.2-1.0 wt% Si, 0.3-5.0 wt% Zn, 0.003-0.3
700% to 100% of a copper alloy in which wt% of P is added to Cu.
Heat treatment to 0 ° C., solution rolling, cold rolling at a working rate of 20 to 80%, aging treatment at 400 to 500 ° C. for 0.5 to 3 hours, and cooling at a working rate of 10 to 70% Rolling between 3
Provided is a method for producing a copper alloy material subjected to aging treatment at 50 to 450 ° C. for 0.5 to 3 hours.

According to this method, Ni and Si facilitate precipitation of precipitates and reduce the amount of elements remaining in a solid solution state, so that strength and conductivity are improved. Further, Zn and P act to improve interfacial peeling at the time of soldering to improve plating properties while ensuring electrical conductivity, and P acts as a deoxidizing agent, while Si acts at the time of alloy casting. Acts to prevent adverse effects due to oxidation of Furthermore, cold rolling at a working ratio of 20 to 80% prevents coarsening while sufficiently generating precipitates during aging treatment. In the aging treatment subsequent to the cold rolling, sufficient precipitation is obtained at 400 to 500 ° C., and necessary strength and electrical conductivity can be obtained. Cold rolling at a working rate of 10 to 70% following the aging treatment is as follows:
It facilitates the generation of precipitates in the next aging treatment (secondary aging treatment) and acts to obtain sufficient strength. 3
The aging treatment at 50 to 450 ° C. for 0.5 to 3 hours enables sufficient precipitation while suppressing coarsening of precipitates, and can obtain necessary strength and electrical conductivity.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, in order to provide both high strength and high electrical conductivity, the Ni ₂ Si compound is deposited as much as possible under the condition that no coarse precipitates are formed. As for the amounts of Ni and Si, when the added amount is large, the amount of solid solution elements that cannot be precipitated increases, and when the amount is small, high strength due to precipitation hardening cannot be achieved. Hereinafter, specific examples will be described with reference to examples.

[0010]

FIG. 1 is a flow chart showing the steps of a method for manufacturing a copper alloy material according to the present invention. The present invention will be described with reference to FIG. The present inventors prepared samples using the compositions shown in Table 1. The compositions according to the present invention were A and B, and three kinds of compositions C, D and E were prepared as comparative compositions (conventional examples).

[0011]

[Table 1]

Ni 2.5 wt%, Si 0.5 wt%, Z
A copper alloy having a composition of n0.5 wt% and P0.03 wt% is melted in an induction melting furnace using oxygen-free copper as a base material, and has a diameter of 3
It was cast into an ingot of 0 mm and length of 250 mm (step 101). This ingot was heated to 850 ° C. and hot-extruded to form a plate having a width of 20 mm and a thickness of 8 mm. Thereafter, the thickness is 0.58 mm while sandwiching intermediate annealing.
Cold-rolled until step 102. Then, 800
After heating to ° C., it was quenched in water to form a solution (step 103). The solution after solution cooling was cold-rolled to a thickness of 0.38 mm (step 104), and was aged at 450 ° C. for 1 hour (first aging treatment) (step 105).

By performing cold rolling between the solution treatment and the aging treatment, appropriate lattice defects are introduced into the crystal lattice of the solution-treated material. This lattice defect functions as a nucleus for the formation of precipitates, and the precipitates can be generated in a more uniform and large amount in a fine shape. When the working ratio of the cold rolling is increased, a larger amount of lattice defects is introduced, so that a large amount of precipitates are easily formed. However, since the precipitation proceeds quickly, the coarsening proceeds rapidly. Therefore, the working ratio of the cold rolling is preferably set to 20 to 80%.

In the one-hour aging treatment, it is important to generate as many precipitates as possible in a fine shape.
For this purpose, the temperature and the holding time are important. Here, the temperature is set to 400 to 500 ° C., and the holding time is set to 30 minutes to 3 hours. At lower temperatures and shorter times, a sufficient amount of precipitation does not occur, and conversely, at higher temperatures and longer times, coarse precipitates are generated.

After the aging treatment for one hour, the thickness becomes 0.25
mm (step 106). This cold rolling is desirably performed at a working ratio of 10 to 70%. If it is less than 10%, the generation of precipitates in the subsequent secondary aging treatment will be insufficient, and if it exceeds 70%, the progress of precipitation will be fast. After this cold rolling, 420 ° C
For one hour (step 107). In this second aging treatment (secondary aging treatment), it is important to precipitate as much as possible of the solid solution elements remaining without being precipitated in the first aging treatment in step 105. Therefore, the temperature of the second aging treatment is set to 350 to 450 ° C., and the holding time is set to 3
0 minutes to 3 hours. The sample manufactured as described above was designated as No. Let it be 1.

Samples (Nos. 2, 3 and N) of the products of the present invention were prepared according to the above-mentioned manufacturing process by changing the compositions shown in Table 1 and changing the processing conditions (the cold working ratio and the aging treatment conditions).
o. 8) and comparative products (No. 4, 5, 6, 7 and No. 8).
9, 10, 11). For all of these,
When the tensile strength and the electrical conductivity were measured, the results shown in Table 2 were obtained.

[0017]

[Table 2]

As is clear from Table 2, Sample No. 1 to
3 and No. 3 8, a strength of 720 MPa or more is obtained,
A conductivity of 52% IACS or more was obtained. As a result, Q
It can be used for a lead frame of a semiconductor device using FP. On the other hand, the sample No. 4-7 and N
o. Comparative Examples 9 to 11 have low tensile strength and low electrical conductivity,
It cannot be used for a lead frame of a semiconductor device.

Since the copper alloy according to the present invention has high strength and high electrical conductivity, when it is used for a lead frame, it is possible to cope with a semiconductor device for the purpose of downsizing, multi-pin, and high-speed. In particular, it is suitable for use in a multi-pin lead frame such as a QFP. Here, the composition ratio of each element shown in Table 1 will be described.

When the amounts of Ni and Si are small, the high strength due to precipitation hardening becomes insufficient. Conversely, when the added amount of Ni and Si increases, the amount of solid solution elements that cannot be completely precipitated increases. The reason for defining the weight ratio of Ni / Si is that
This is to reduce the amount of Ni or Si existing as a surplus when i ₂ Si is sufficiently precipitated. Furthermore, Zn has an effect of improving interface peeling during soldering. P has an effect as a deoxidizing agent, and S at the time of alloy casting
An adverse effect due to oxidation of i can be prevented. When the amounts of Zn and P are larger than predetermined amounts, the electrical conductivity decreases.

The compositions in Table 1 are not fixed to the values in the table but can be selected in the following ranges.
Ni 1.0 to 5.0 wt%, Si 0.2 to 1.0 wt%
%, Zn 0.3 to 5.0 wt%, P 0.003 to 0.3
wt%, and Ni / Si = 4.5-5.5. In the hot extrusion in step 102, the heating is performed at 800 ° C., but the temperature can be set in the range of 700 to 1000 ° C. Further, the first step 105
The next aging treatment was performed at 450 ° C, but can be performed at a temperature in the range of 400 to 500 ° C.

[0022]

As is clear from the above, according to the present invention, in addition to Ni and Si in a predetermined ratio, a copper alloy in which Zn and P are added to Cu in a predetermined composition in a range of 700 to 1000.
And then cold-rolled at a working rate of 20-80%, and further subjected to aging treatment at 400-500 ° C for 0.5-3 hours, and then again at a working rate of 10-70%. Since cold rolling is performed and then aging treatment is performed again at 350 to 450 ° C. and 0.5 to 3 hours, a copper alloy having high strength and high electrical conductivity can be obtained. Therefore, when used for a lead frame, it is possible to obtain a semiconductor device such as a QFP compatible with miniaturization, multi-pin operation and high-speed operation.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a manufacturing process of a method for manufacturing a copper alloy material of the present invention.

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Claims (2)

[Claims] 1. A 1.0-5.0 wt% Ni having a weight ratio Ni / Si of 4.5-5.5, and 0.2-1.0 w
t% of Si, 0.3 to 5.0 wt% of Zn, and 0.1% of Zn.
003-0.3 wt% of P, it is configured to have a conductivity of 50% IACS or more and a tensile strength of 700 MPa or more by predetermined solution treatment, cold rolling and aging treatment. Copper alloy material. 2. A 1.0-5.0 wt% Ni having a weight ratio Ni / Si of 4.5-5.5, and 0.2-1.0 w.
t% of Si, 0.3 to 5.0 wt% of Zn, and 0.1% of Zn.
003-0.3 wt% of the copper alloy containing P added to Cu is heated to 700-1000 ° C for solution treatment, cold-rolled at a working ratio of 20-80%, and 400-500 ° C. A method for producing a copper alloy material comprising subjecting to aging treatment for 5 to 3 hours, cold rolling at a working rate of 10 to 70%, and aging treatment at 350 to 450 ° C. for 0.5 to 3 hours. .