JPH1022433A - Iron-chromium alloy lead frame material having excellent anticorrosive property and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the thermal conductivity and plating property, reduce the difference in natural potential at the time of Pd plating, and prevent deterio ration in anticorrosive property, by applying Cu or a Cu alloy onto the surface of a Fe-Cr alloy lead frame material and providing a Pd plating layer on the surface thereof. SOLUTION: Cu or a Cu alloy is applied onto one side or both sides of a Fe-Cm alloy lead frame material containing C at 0.03% or less, Si at 0.5% or less, Mn at 0.5% or less, P at 0.02% or less, S at 0.02% or less, Cr at 5-13%, and Fe for the remaining part. In addition, a Pd plating layer is provided on the surface thereof. Thus, the thermal conductivity is increased, thereby improving the thermal radiation and plating property. Moreover, by carrying out diffusion heating processing after forming the Pd plating layer, a diffusion layer is generated on each other. Thus, the difference in natural potential is further reduced and generation of a local battery is eliminated, thereby preventing deterioration in anticorrosive property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an anticorrosive F
The present invention relates to an e-Cr alloy-based lead frame material and a method for manufacturing the same.

[0002]

2. Description of the Related Art Heretofore, as a lead frame material, a lead frame material of an Fe-Ni based alloy mainly composed of 30 to 55% of Ni and a lead frame material of a Cu alloy have been used. Fe of these lead frame materials
-Ni alloy-based lead frame materials have the following advantages: thermal expansion coefficient is close to that of Si chip, good plating and solder wettability, high strength, etc. Low heat dissipation is inferior because of its low cost, and there are drawbacks such as high cost. Further, the Cu alloy-based lead frame material has a good heat dissipation property due to its high thermal conductivity and also has excellent points such as workability, but has disadvantages such as low strength.

Further, a lead frame material of Fe—Cr alloy, which is superior in corrosion resistance and lower in cost than a lead frame material of Fe—Ni alloy and has higher strength than a lead frame material of Cu alloy, ie, C: 0 .03% or less, S
i: 0.5% or less, Mn: 0.5% or less, P: 0.02
%, S: 0.02% or less, Cr: 5 to 10%, and a Fe-Cr alloy-based lead frame material composed of the balance Fe is also known.

[0004] However, this Fe-Cr alloy lead frame material is inferior in plating property due to formation of Cr oxide on the surface, and has low heat conductivity, so that heat dissipation is lower than that of Cu alloy. There was a drawback that the properties were inferior. In addition, Pb solder is plated on the lead frame material in order to improve the solderability, but it is required to eliminate Pb due to environmental problems. Recently, plating of Pd has been studied. I have. However, when Pd was plated on the Fe-Cr alloy lead frame material, it was found that the corrosion resistance was deteriorated as compared with that before plating, due to the local battery.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a Pd-plated Fe-Cr alloy-based lead frame material having excellent corrosion resistance and a method for producing the same.

[0006]

In order to achieve the above-mentioned object, the present invention provides an Fe--Cr alloy lead frame material having excellent corrosion resistance, which comprises Cu or Cu on one or both sides of an Fe--Cr alloy lead frame material. That is, an alloy was coated, and a Pd plating layer was further provided on this surface.

Further, in order to achieve the above object, the Fe—Cr alloy-based lead frame material of the present invention, which has excellent corrosion resistance,
Cu or Cu alloy coated on one or both sides of Fe-Cr alloy lead frame material and P plated on it
This is to provide a diffusion layer in which d is heated and diffused mutually.

Further, in order to achieve the above object, a method for producing an Fe—Cr alloy-based lead frame material according to the present invention comprises:
That is, Cu or a Cu alloy is coated on the surface of an e-Cr alloy-based lead frame material, a Pd plating layer is further provided on the surface, and diffusion heating is performed in an inert gas at 400 to 800 ° C.

Next, the present invention will be described in more detail. The Fe—Cr alloy-based lead frame material of the present invention
Alloy: C: 0.03% or less, Si: 0.5% or less, M
n: 0.5% or less, P: 0.02% or less, S: 0.02
% Or less, Cr: 5 to 13%, and the balance of Fe is suitable. Further, the Cu alloy covering the surface of the Fe—Cr alloy system of the present invention has Ni: 2 to 3% and Si: 0.4 to
0.6%, alloy consisting of the balance Cu, Zn: 0.6-0.
8%, Si: 0.8 to 1.0%, and the balance Cu.

[0010] The lead frame material of the present invention Cu or C
The method for coating the u alloy may be vacuum deposition, thermal spraying, rolling welding, or the like, in addition to electrolytic plating. Further, Pd plating of the lead frame material of the present invention can be performed by chemical plating, vacuum deposition, or the like, in addition to electrolytic plating.

[0011] The thickness of the lead frame material of the present invention is 0.1 mm.
05 to 0.25 mm, the proportion of Cu is 6
0% or less, and a Pd plating thickness of 3 μm or less are preferable. C
This is because if the ratio of u exceeds 60% in the thickness ratio, the strength decreases. The reason why the temperature of the diffusion heat treatment of the present invention is limited to 400 to 800 ° C. is that if the temperature is lower than 400 ° C., diffusion is not sufficiently performed, and if the temperature is higher than 800 ° C., crystal grains become coarse. is there.

[0012]

The lead frame material of the present invention is made of a Fe—Cr alloy lead frame material having Cu or C on one or both sides.
Coating with u alloy increases thermal conductivity, improves plating properties, reduces the difference in spontaneous potential when Pd is plated, reduces the occurrence of local batteries, and degrades corrosion resistance. Almost no. Further, the lead frame material of the present invention is obtained by coating one or both surfaces of a Fe-Cr alloy-based lead frame material with Cu or a Cu alloy, further providing a Pd plating layer on this surface, and then performing a diffusion heating treatment. As a result, a diffusion layer is formed mutually, and the difference in the natural potential is further alleviated, and no local battery is generated, so that the corrosion resistance does not deteriorate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described, but the present invention is not limited by these embodiments. C: 0.018%, Si: 0.23 as Fe-Cr alloy
%, Mn: 0.48%, P: 0.002%, S: 0.0
An alloy comprising 08%, Cr: 7.1% and the balance Fe was melted and subjected to hot forging, hot rolling, cold rolling, and continuous bright annealing to obtain a 0.15 mm thick plate. Thereafter, a Cu plate having a thickness of 0.03 mm was formed on both surfaces of the plate by cold rolling and pressure welding to form a clad, thereby reducing the total thickness to 0.15 mm. Furthermore, P is applied on this with the following electroplating bath and plating conditions.
d was plated by 0.3 μm. The lead frame material manufactured in this manner is shown in Table 1 as Pd / Cu / Fe-7Cr.

Palladium (as Pd (NH ₃ ) ₂ (NO ₂ ) ₂ ) 13 g / l Ammonium sulfamate 100 g / l pH (in ammonia water) 8.0 Temperature 27 ° C. Current density 0.6 A / dm ² Anode Platinum coated Anode time 1 minute

The Pd / Cu / Fe-7Cr is converted to A
Heated at 600 ° C. for 2 minutes (diffusion heat treatment) in an r atmosphere is shown in Table 1 as hPd / Cu / Fe-7Cr. Fe-7% Cr in Table 1 is the same as Pd / Cu in Table 1.
/ Before plating with Cu and Pd of Fe-7Cr, it is a comparative material of the present invention. Further, Fe-42% in Table 1 was used.
Ni is a lead frame material that has been widely used in the past, and is a comparative material of the present invention.

Table 1 shows the tensile strength, elongation, electrical conductivity, and rust generation rate of these lead frame materials. The electric conductivity in this table is a ratio when C (carbon) is set to 100. Further, the rust occurrence rate is obtained by testing the rust in accordance with JIS Z 2371 salt water spray test method, obtaining the area of the rust generated by image processing, and expressing the area ratio on the surface of the test material.

[0017]

[Table 1]

The Pd / Cu / Fe-7Cr material of the present invention comprises:
Although the tensile strength and the elongation are almost the same as compared with the comparative material Fe-42% Ni, the electric conductivity is significantly higher,
It can be seen that the rust generation rate is also low. The hPd / Cu / Fe-7Cr material subjected to the diffusion heating treatment of the present invention has a slightly lower tensile strength than the comparative material Fe-42% Ni, but has a significantly higher electric conductivity and a higher rust resistance. It can be seen that the incidence rate has been greatly reduced and the elongation has been greatly increased.

In the above embodiment, the rolling pressure welding method was used as the method of coating Cu, but similar results can be obtained by employing other methods such as electrolytic plating. Although Pd is electroplated, it can be plated by another method such as vacuum evaporation. Further, in the above embodiment, Cu is coated. However, a lead frame material can be manufactured in the same manner as a Cu alloy coated with a Cu alloy.

[0020]

As described above, according to the present invention, the lead frame material of the present invention has a high thermal conductivity and thus has a good heat dissipation and a good plating property. Furthermore, in the lead frame material of the present invention, the difference in the natural potential is reduced,
An excellent effect is obtained in that the generation of local batteries is slight and the corrosion resistance is hardly degraded.

Claims (3)

[Claims] 1. A surface of an Fe—Cr alloy-based lead frame material is coated with Cu or a Cu alloy.
F excellent in corrosion resistance characterized by providing a d plating layer
e-Cr alloy lead frame material. 2. Corrosion resistance characterized in that a Cu or Cu alloy coated on the surface of an Fe—Cr alloy lead frame material and a diffusion layer formed by heating and diffusing Pd plated thereon are provided. Excellent Fe-Cr alloy lead frame material. 3. The surface of an Fe—Cr alloy-based lead frame material is coated with Cu or a Cu alloy.
a d-plated layer, and a diffusion heat treatment in an inert gas at 400 to 800 ° C.
-Manufacturing method of Cr alloy lead frame material.