JPH0641660A - Cu alloy steel having fine structure for electric and electronic parts - Google Patents

Abstract

PURPOSE:To provide a high strength Cu alloy sheet for electric and electronic parts having a smooth etching face and good in bendability. CONSTITUTION:The high strength Cu alloy sheet for electric and electronic parts has a compsn. contg., by weight, 0.4 to 5% Ni, 0.05 to 1.2% Si, 0.07 to 2.5% Sn, 0.001 to 0.2% Mg, 0.1 to 3% Zn, 0.007 to 0.25% Fe and 0.0002 to 0.03% Mo, and the balance Cu with inevitable impurities and has a fine structure in which the average grain diameter is regulated to be 30mum or smaller and the maximum diameter of precipitates is regulated to be 3mum or smaller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Cu alloy plate material for electric and electronic parts which has a fine structure, resulting in a significantly small surface roughness on the etching surface and excellent bending workability. is there.

[0002]

2. Description of the Related Art Conventionally, as described in, for example, Japanese Patent Laid-Open No. 63-86838, for manufacturing lead materials for semiconductor devices and various electric and electronic parts such as terminals and connectors,
In% by weight (hereinafter,% indicates% by weight), Ni: 0.8 to
4%, Si: 0.1 to 1.2%, Sn: 1 to 4%,
Many other Cu alloy sheet materials are used, including a Cu alloy sheet material containing Mg: 0.2% or less and the balance of Cu and inevitable impurities.

[0003]

On the other hand, in recent years, miniaturization and weight reduction (thinning) of various electric and electronic parts and further high integration have been remarkable, and accordingly, in addition to strength, Cu alloy plate materials have In particular, it is required to have a smooth etching surface, that is, an etched surface with a small surface roughness, and excellent bending workability without cracking during bending under severe conditions. When forming a circuit pattern by etching, it is essential that the surface after etching is smooth.
In the u alloy plate material, the average crystal grain size is usually set to 50 to 100 μm in the state of solution treatment and precipitation treatment,
There are many precipitates mainly composed of nickel silicide such as Ni ₂ Si and having a diameter exceeding 5 μm, which not only causes the surface roughness of the etching surface to become rough, but also causes bending work. At that time, there is a problem that cracks easily occur.

[0004]

Therefore, the present inventors have
As a result of conducting research to develop a Cu alloy plate material having a fine structure, Ni: 0.4 to 5%, Si: 0.0
5 to 1.2%, Sn: 0.07 to 2.5%, M
g: 0.001-0.2%, Zn: 0.1-3%,
Fe: 0.007 to 0.25%, Mo: 0.
A Cu alloy plate material containing 0002 to 0.03%, and the balance of which is composed of Cu and inevitable impurities, is an average in a state of being subjected to solution treatment and subsequent precipitation treatment (aging treatment). The Cu alloy plate material having a grain size of 30 μm or less and a maximum precipitate diameter of 3 μm or less has a fine structure, and thus the Cu alloy plate material having a fine structure exhibits a smooth etched surface with a surface roughness of 1 μm or less. In addition, they obtained the research results that they have excellent bending workability and high strength, and also have excellent solder heat resistance peeling property.

The present invention was made based on the above research results, and Ni: 0.4 to 5%,
Si: 0.05 to 1.2%, Sn: 0.07 to
2.5%, Mg: 0.001-0.2%, Z
n: 0.1 to 3%, Fe: 0.007 to
0.25%, Mo: 0.0002 to 0.03%, with the balance being Cu and unavoidable impurities, the average crystal grain size being 30 μm or less, and the maximum precipitate size being 3
It is characterized by a Cu alloy plate material for electric and electronic parts, which has a fine structure of not more than μm, particularly has a smooth etching surface, excellent bending workability, and excellent solder heat resistance peeling property.

Next, the reason why the composition of the Cu alloy sheet material of the present invention is limited as described above will be explained. (A) Ni and Si With these components, a precipitate mainly composed of Ni ₂ Si which is finely dispersed and precipitated on the substrate after the precipitation treatment is formed, and thus the strength is improved without significantly decreasing the conductivity. There is a function, but the content is Ni: 0.4%
If the content is less than Si and less than 0.05%, the desired strength cannot be secured. On the other hand, if the content exceeds Ni: 5% and Si: 1.2%, the conductivity and the solder heat peeling property are deteriorated. As a result, the contents were determined to be Ni: 0.4 to 5% and Si: 0.05 to 1.2%, respectively.

(B) Sn The Sn component has the action of forming a solid solution in the base material to further improve the strength, but if the content is less than 0.07%, the desired effect cannot be obtained for the action, while Its content is 2.5%
If it exceeds 1.0, the conductivity will decrease, so the content was set to 0.07 to 2.5%.

(C) Mg The Mg component has the function of improving hot workability,
If the content is less than 0.001%, the desired hot workability-improving effect cannot be obtained, while if the content exceeds 0.2%, Mg oxide or the like tends to be caught in the ingot, which is Since the hot ductility and the surface cleanability are impaired due to the cause, the content thereof is set to 0.001 to 0.2%.

(D) Zn The Zn component has the function of forming a solid solution in the base material to improve the solder heat resistance peeling property, but if the content is less than 0.1%, the desired solder heat resistance peeling property is secured. However, even if the content exceeds 3%, no further improvement effect appears, so the content was set to 0.1 to 3%.

(E) Fe and Mo These components suppress coarsening of crystal grains at the time of heating at high temperature during solution treatment, and prevent coarsening of precipitates, thereby improving surface roughness after etching. While smoothing to 1 μm or less, it has an effect of suppressing the occurrence of cracks even in severe bending, but the content of each is Fe: 0.0
If the content is less than 07% and Mo: less than 0.0002%, the desired effect cannot be obtained, while the content of Fe:
If it exceeds 0.25% and Mo: 0.03%, the hot rolling property and the bending workability are deteriorated, so the contents are Fe: 0.007 to 0.25%, Mo: 0.
It was defined as 0002 to 0.03%.

[0011]

EXAMPLES Next, the Cu alloy sheet material of the present invention will be specifically described by way of examples. In a normal low frequency groove type melting furnace,
Cu alloy melts each having the composition shown in Tables 1 to 3 were prepared, and the thickness was 160 mm × width: by the semi-continuous casting method.
450mm x length: 1600mm as an ingot,
This ingot is hot-rolled at a predetermined rolling start temperature within the range of 750 to 980 ° C. to obtain a hot-rolled sheet with a thickness of 11 mm,
After cooling with water, the hot-rolled sheet was chamfered by 0.5 mm on each of the upper and lower sides and 3 mm on each side, and the rolling ratio was 87.
% Cold-rolled into a cold-rolled sheet with a thickness of 1.32 mm,
In addition, 1 to a predetermined temperature in the range of 400 ~ 650 ℃
In the state where the intermediate refining for holding time is performed, cold rolling with a rolling ratio of 75% is performed to form a cold rolled sheet with a thickness of 0.33 mm, which is then brought to a predetermined temperature within the range of 750 to 950 ° C. 5-3
After holding for 00 seconds, the temperature range of 750 to 500 ° C is changed to 40
The solution treatment that cools at a cooling rate of ℃ / sec or more is applied,
Subsequently, a precipitation treatment of holding for 3 hours at a predetermined temperature in the range of 400 to 500 ° C. is performed, and further cold rolling at a rolling rate of 25% is performed, and finally to a predetermined temperature in the range of 250 to 350 ° C. By performing the strain relief annealing of holding for 1 hour, the Cu alloy sheet materials 1 to 14 of the present invention, the comparative Cu alloy sheet materials 1 to 9 having the average crystal grain size and the maximum precipitate diameter similarly shown in Tables 1 to 3 respectively, and the conventional one. Cu alloy plate materials 1 to 4 were manufactured.

In the comparative Cu alloy sheet materials 1 to 9, the content of any one of the constituents of the Cu alloy (marked with *) is out of the range of the present invention. The average crystal grain size was measured using an optical microscope, and the precipitate was measured using a scanning electron microscope at 10 times at a magnification of 5000 times. The indicated precipitate was shown.

Next, with respect to various Cu alloy sheet materials obtained as a result, the tensile strength and elongation were measured by a tensile test based on JIS Z2241, and JIS H05 was also used.
The electrical conductivity was measured based on No. 05, a bending test and a solder thermal peeling test were performed, and the surface roughness of the etched surface was also measured.

The bending test is performed according to JIS Z2248 V
According to the block method, the bending axis is set in the rolling parallel direction (bad way direction), and the minimum bending radius: r (mm) at which cracks occur on the surface of the test piece is measured, and this r and the thickness of the test piece: t Ratio: r / t.

Thermal peel test of solder, thickness: 0.25 mm
× width: 15 mm × length: a test piece having a dimension of 60 mm,
Treated with rosin flux, temperature: 230 ° C, 60% S
It is dipped in a solder bath of n-40% Pb alloy to make the solder adhere to its surface, and in this state, in air, at temperature:
After heating at 150 ℃ for 1000 hours, after heating,
The test piece was tightly bent by 180 ° and then bent again by 180 °, and the presence or absence of solder peeling at this 180 ° bent portion was observed to evaluate the heat peeling resistance of the solder.

The surface roughness of the etched surface is such that after degreasing the surface of the test piece, it is immersed in a 42% ferric chloride aqueous solution at a temperature of 45 ° C. and etched by 0.1 ± 0.02 mm in the thickness direction. Then, on the resulting etched surface, the surface roughness was measured at an arbitrary 10 points in lengths of 0.8 mm in the direction perpendicular to the rolling direction, and the highest (rough) surface was obtained from the measurement results at these 10 points. The roughness is shown. The measurement results are shown in Tables 4 and 5.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

[Table 4]

[0021]

[Table 5]

[0022]

From the results shown in Tables 1 to 5, the present invention C is obtained.
u alloy plate materials 1 to 14 are all conventional Cu alloy plate materials 1 to 14.
It has the same high strength and conductivity as No. 4, while the surface roughness and bending workability of the etched surface, and the heat-resistant peeling property of the solder are much better than those of the conventional Cu alloy sheet materials 1 to 4. And comparative Cu alloy plate materials 1 to 9
As can be seen from the above, when the content of any one of the constituents of the Cu alloy is out of the range of the present invention, it is clear that at least one of the above-mentioned characteristics becomes inferior. .

As described above, the Cu alloy sheet according to the present invention has a smooth etching surface, excellent bending workability, and excellent heat peeling resistance of solder. When used for the manufacture of various electrical and electronic parts such as lead frame materials for highly integrated semiconductor devices and terminals and connectors whose shapes are complicated and tend to be thin, long-term excellent performance is obtained. It works.

Front page continued (72) Inventor Manpei Kuwahara 128-7 Ogimachi, Aizuwakamatsu, Fukushima Prefecture Mitsubishi Shindoh Co., Ltd. Wakamatsu Manufacturing (72) Inventor Shunichi Chiba 128-7, Ogimachi, Aizuwakamatsu, Fukushima Mitsubishi Shindoh Co., Ltd. Wakamatsu (72) Inventor Nao Sakakibara 128-7 Ogimachi, Aizuwakamatsu, Fukushima Prefecture 128-7 Mitsubishi Shindoh Co., Ltd. Wakamatsu Manufacturing (72) Inventor Michiyo Odajima 128-7, Ogimachi, Aizuwakamatsu, Fukushima Mitsubishi Shindoh Co., Ltd. Wakamatsu Manufacturing Co., Ltd. (72) Inventor Junichi Kumagai 128-7 Ogimachi, Aizuwakamatsu, Fukushima Prefecture Wakamatsu Works, Mitsubishi Shindoh Co., Ltd.

Claims (1)

[Claims] 1. By weight%, Ni: 0.4-5%,
Si: 0.05 to 1.2%, Sn: 0.07 to
2.5%, Mg: 0.001-0.2%, Z
n: 0.1 to 3%, Fe: 0.007 to
0.25%, Mo: 0.0002 to 0.03%, with the balance being Cu and unavoidable impurities, the average crystal grain size being 30 μm or less, and the maximum precipitate size being 3
A Cu alloy plate material for electric and electronic parts, which has a fine structure of not more than μm.