JPS60245754A - High strength copper alloy having high electric conductivity - Google Patents

Abstract

PURPOSE:To obtain a Cu alloy having superior strength, spring characteristics and electric conductivity by adding specified amounts of Sn, P, Fe, Ni, and other elements to Cu and making the content of O2 as an impurity as low as possible. CONSTITUTION:A Cu alloy consisting of, by weight, 0.8-4.0% Sn, 0.01-0.4% P, 0.05-1.0% Fe, 0.05-1.0% Ni, 0.01-1.0% one or more among Al, Hf, Be, Mo, Te, Pb, Co, Zr, Nb, B, Mg, Mn, Si, Sb, Ti, In, As and Zn, and the balance Cu with impurities including O2 reduced to <=0.0020% is used as a material for a spring for an electric apparatus, a spring for an instrument or a spring for a switch or a connector. The Cu alloy has superior strength and spring characteristics without deteriorating the electric conductivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to lead materials, connectors, and terminals for semiconductor devices such as transistors and integrated circuits (ICs).

This invention relates to a copper alloy suitable for conductive spring materials such as relays and switches.

Conventionally, Kovar (Fe-z9N1-16co) has been used as a lead material for semiconductor devices because of its low coefficient of thermal expansion and good adhesion and sealing properties with elements and ceramics.

High nickel alloys such as Alloy 42 (F13-42N1) have been preferred. However, in recent years, with the increase in the degree of integration of semiconductor circuits, the number of IOs with high power consumption has increased, resins are often used as sealing materials, and improvements have been made to the bonding between elements and lead frames. As a result, copper-based alloys with good heat dissipation properties have come to be used as lead materials.

Generally, lead materials for semiconductor devices are required to have the following properties.

(1) The lead is an electrical signal transmission part.

Materials that exhibit excellent thermal and electrical conductivity are required to have the ability to release heat generated during the packaging process and circuit use to the outside.

(2) Since the adhesion between the lead and the mold is important from the viewpoint of protecting the semiconductor element, the thermal expansion coefficients of the lead material and the mold material should be similar.

(3) Good heat resistance as various heating processes are added during packaging.

(4) Most leads are made by punching or bending the lead material.

These must have good workability.

(5) The surface of the lead is plated with precious metal.

Good plating adhesion with these precious metals.

(6) Exposed outside the sealing material after packaging. Since many items are soldered to the so-called outer lead part, good soldering shows the properties.

(7) Good corrosion resistance from the standpoint of equipment reliability and lifespan.

(8) The price must be low.

Oxygen-free steel, soot-containing copper, and iron copper have been conventionally used to meet these various required characteristics.

Phosphor bronze, Kovar, and 42 alloy all have advantages and disadvantages, and cannot necessarily satisfy all of these characteristics.

Also, conventional springs for electrical equipment and springs for measuring instruments.

As materials for springs used in switches, connectors, etc., inexpensive brass, nickel silver, which has excellent spring properties and corrosion resistance, or phosphor bronze, which has excellent spring properties, have been used. but.

Brass has inferior strength and spring characteristics, and has a strength of 9.

Nickel silver and phosphor bronze, both of which have excellent spring properties, also contain 18% by weight of Ni and 8% by weight of Sn, so there are processing constraints such as poor hot workability due to raw materials and manufacturing. In addition, it was an expensive alloy.

Furthermore, when used for electrical equipment, etc., it has a drawback of low electrical conductivity. Therefore.

The emergence of an inexpensive alloy with good electrical conductivity and excellent spring properties has been awaited.

The present invention has been made in view of the above, and aims to improve the drawbacks of conventional copper-based alloys and provide a copper alloy having various properties suitable as lead materials and conductive spring materials for semiconductor devices. be.

The present invention has Sn 0.8-4.0 weight 4. Po, 01
-0.4% by weight, Ni0.05-1.0% by weight'11.
FeO,05-t 0% by weight and AI, Hf,
Be, Mo, Te, Pb, Co, Zr, N
b, B, Mg.

Mn, Si, Sb, Ti, In, As, Z
Contains 001 to 1.0% by weight of one or more of n,
An alloy in which the balance consists of Cu and unavoidable impurities, or an alloy in which the content of oxygen among these unavoidable impurities is 0.0020% by weight or less, and is an excellent electrical and thermal steel alloy for lead materials of semiconductor devices. conductivity.

Excellent heat resistance, workability, plating adhesion, and solderability.

It is characterized by having corrosion resistance, etc., and also exhibiting excellent high strength, spring properties, and conductivity as a conductive spring material.

Next, the reason for limiting the alloy components constituting the alloy of the present invention will be explained. The reason for setting the content of an to 0.8 to 4.0% by weight is that when the Sn content is less than 0.8% by weight, the expected strength cannot be obtained even when P is co-added.

Conversely, if the Sn content exceeds 4.0% by weight, the electrical conductivity will decrease and the price will also increase. P content from 0.01 to
The reason for setting it at 0.4% by weight is that when the P content is less than 0.011% by weight, the improvement in strength and heat resistance due to P content is not remarkable (but when the P content exceeds 0.04% by weight, the Sn content This is because the conductivity decreases significantly regardless of the Ni
The reason why the Ni content is set to 005 to 1.0% by weight is that the expected strength cannot be obtained when the Ni content is 00505% by weight.
This is because when the content exceeds 10% by weight, the conductivity decreases significantly. The reason for setting the Fe content to 0.05 to 1.0% by weight is that if it is less than 0.055% by weight, the improvement in strength and heat resistance due to Fe content is not remarkable (and if it exceeds 1.0% by weight, the conductivity is reduced). This is because the decrease in the rate is significant.In addition, AI, as a subcomponent,
Hf, Be.

λKo, Te, Pb, Co, Zr, Nb,
B, Mg, Mn, Si, Sb, Ti, In,
As.

Containing one or more types of Zn improves strength and spring properties, but if the content is less than 10% by weight, the effect cannot be expected much, and if it exceeds 10% by weight, the electrical conductivity will decrease. 0.01 to 1, as the decrease will be significant.
．． It was set to 0% by weight. Why was the oxygen content set at 0.0020% by weight?

This is because if it exceeds 0.0020% by weight, plating adhesion will decrease.

The alloy of the present invention is a copper alloy that has excellent strength, spring properties, heat resistance, and electrical conductivity, and also has good solderability and plating adhesion. or.

Its coefficient of thermal expansion is close to that of plastic, making it suitable for plastic packages as a lead material for semiconductor devices. Therefore, the alloy of the present invention is suitable as a lead material and a conductive spring material for semiconductor devices, and no prior art alloy has such comprehensive properties.

The material of the present invention will be explained below with reference to Examples.

EXAMPLES Ingots having various compositions of the alloys of the present invention shown in Table 1 were melted and cast using electrolytic copper or oxygen-free steel as raw materials in a high-frequency melting furnace in air, an inert atmosphere, or a reducing atmosphere. This was then hot rolled at 800°C to form a 4m thick plate.

The surface side was cold rolled to a thickness of 1.0. This is 5
After annealing at 00°C for 1 hour, it was cold rolled into a plate with a thickness of 08°C and evaluated as a lead material. For evaluation, strength and elongation were determined by a tensile test, heat resistance was determined by softening temperature at a heating time of 5 minutes, and electrical conductivity (heat dissipation) was determined by electrical conductivity (%IAC8). For soldering, use the vertical immersion method in a soldering bath at 230°C ± 5°C (tin 60%,
The solder wetting condition was evaluated by visually observing the wetting state of the solder after immersing it in the solder for 5 seconds.

Plating adhesion was determined by applying 3μ thick Ag plating to the sample.
Evaluation was made by heating at 450° C. for 5 minutes and visually observing the presence or absence of blisters generated on the surface of 2. These results are shown in Table 1 along with comparative alloys.

In addition, in order to evaluate it as a spring material, 1.
After annealing the 0-fin material at 500℃ for 1 hour, it was cold rolled into a plate with a thickness of 0.5mm, which was strained and annealed at various temperatures from 150 to 500℃ to increase the strength and elongation. The spring properties were evaluated by tests and the results of electrical conductivity were added to this and are shown in Table 2 together with comparative alloys.

Note that the soldering properties and plating adhesion were almost the same as the results for the lead material, so they were omitted.

Claims (2)

[Claims] (1) Eln 0.8-4.0% by weight, P0.01~
0.4 weight section. NiO, 05-1,0% by weight, FeO, 05-1,0% by weight and Al, Hf, Be, Mo, Te, P
b, Co, Zr, Nb, B, Mg, Mn,
Si. One of Eb, Ti, In, As, Zn or 2'p
A high-strength, high-conductivity copper alloy characterized in that fi or more is engaged by 0.01 to 1.0 weight, and the remainder consists of O and unavoidable impurities. (2) Sn0.8-4.0 heavy fgl po, o 1
-0.4 weight section. NiO, 0.05-1.0% by weight, Fe0.05-1.0% by weight and AI, Hf, Be, Mo, Te, P
b, Co, Zr, Nb, B, Mg, Mn,
Si. One or more of Sb, Ti, In, As, and Zn are incorporated by weight in the range of 0.001 to 1.0%, the remainder being O and inevitable impurities, and the content of oxygen among the impurities is 0.001 to 1.0% by weight.
A high-strength, high-conductivity copper alloy characterized by having a weight coefficient of 0020 or less.