JPH046231A - High strength and high conductivity copper alloy for electronic equipment - Google Patents

Abstract

PURPOSE:To obtain an inexpensive high strength and high conductivity copper alloy for electronic equipment excellent in strength, electrical conductivity, heat resistance, bendability or the like by specifying the compsn. constituted of Cr, Sn, Ni and Cu. CONSTITUTION:This is a high strength and high conductivity copper alloy for electronic equipment contg., by weight, 0.005 to 1.5% Cr, 0.28 to 1.0% Sn and 0.01 to <0.2% Ni, furthermore contg., as assistant components, total 0.01 to 2.0% of one or more kinds among Al, Be, Hf, In, Ti and Zr and the balance Cu with inevitable impurities. The alloy is excellent in properties such as bendability or the like as well and is suitable for electrical conducting spring materials or the like such as the lead frame material, terminal, etc., of a semiconductor integrated circuit.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides high-strength, high-conductivity copper for electronic equipment suitable for conductive spring materials such as semiconductor integrated circuit (IC) lead frame materials and terminals, connectors, relays, switches, etc. It concerns alloys.

[Prior Art and Problems] Conventionally, as lead materials for semiconductor devices, Kovar (Fe-29NilEico) and 42 alloy (Fe High nickel alloys such as -42N i ) have been preferred. However, in recent years, as the degree of integration of semiconductor circuits has improved, the number of ICs with high power consumption has increased, resins have been increasingly 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) Leads must exhibit excellent thermal and electrical conductivity, as they are required to act as an electrical signal transmission part and also have the function of discharging 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) It must have good heat resistance since various heating processes are involved during packaging.

(4) Most leads are manufactured by punching or bending lead material, so the workability of these is good.

(5) Since the surface of the lead is plated with precious metals, the plating adhesion to these precious metals must be good.

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

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

(8) Prices are low.

Alloys conventionally used have advantages and disadvantages with respect to these various required characteristics, and no one has been found that satisfies these requirements.

In addition, as spring materials for terminals, connectors, relays, switches, etc., inexpensive brass, nickel silver, which has excellent spring properties and corrosion resistance, or phosphor bronze, which has excellent spring properties, have been used. However, brass has inferior strength and spring characteristics, nickel silver, which has excellent strength and spring characteristics, contains a large amount of Ni, and phosphor bronze contains a large amount of Sn, so there are problems in terms of raw materials and manufacturing. It was an expensive alloy due to processing constraints such as poor hot workability. 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.

[Means for Solving the Problems] In view of the above points, as a result of various researches, the present invention has been developed to provide an inexpensive product that has high strength, high conductivity, excellent bending workability, and excellent other properties. The aim is to provide a copper alloy with excellent properties.

That is, the present invention contains Cr 0.05 to 1.5 vt%,
Sn 0.28~1.0wt%, Ni 0.01~
Contains less than 0.2vt%, or further contains A as a subcomponent
1. Be.

I selected from the group consisting of Hf, In5TLs Zr
Contains N or two or more types in a total amount of 0.01 to 2.0 νt%,
This is a high-strength, high-conductivity copper alloy for electronic devices, characterized in that the remainder consists of Cu and unavoidable impurities.

[Detailed description of the invention] Next, the reasons for limiting the alloy components constituting the present invention will be explained.

Cr is added to improve strength and heat resistance, and the reason for setting the content to 0.605 to 1.5 wt% is that if it is less than 0.05 wt%, the above-mentioned effect cannot be expected; This is because if it exceeds 5vt%, the electrical conductivity, plating adhesion, and solderability will significantly deteriorate.

Sn is added to improve strength and spring characteristics, and the content is set to 0.28 to 1.0 wt% because
This is because if the content is less than 0.28 wt%, the above-mentioned effect cannot be expected, whereas if it exceeds 1.0 wt%, a significant decrease in conductivity will occur.

Ni is added because it can make the recrystallized grains into uniform fine grains of 10μ or less during the final heat treatment where recrystallization occurs in the manufacturing process, and it can improve the bending workability of the alloy. be.

The final heat treatment may be hot rolling, solution treatment, or the like. Ni content is 0. C11~0.2
The reason why it is set to be less than 0.1 νt % is because the above-mentioned effect cannot be expected if it is less than 0.2 νt %, and a significant decrease in conductivity occurs when it is 0.2 νt % or more.

Furthermore, the total amount of one or more selected from the group consisting of A1, Be5Hf, and In5TiSZr is 0.01 to
The reason for adding 2.0wt% is that it can be expected to have the effect of improving strength without significantly reducing conductivity, but if the total amount is less than 0.01wt%, the above-mentioned effect cannot be expected.
On the other hand, if it exceeds 2.0 wt%, significant deterioration in conductivity and processability will occur.

[Example code] Next, the present invention will be specifically explained using examples.

Ingots having various compositions of the present invention alloy and comparative alloy shown in Table 1 were melted using electrolytic copper or oxygen-free copper as a raw material in a high-frequency melting furnace in air, an inert atmosphere, or a reducing atmosphere. After performing the face side of these ingots, 850℃
Hot rolled to a thickness of 8mm, and after the face side, the thickness was 1mm.
．． It was cold rolled to a thickness of 5. Thereafter, solution treatment was performed at 950°C, cold rolling was performed to form a plate with a thickness of 0.25 mm, and finally aging treatment was performed at 400°C. In this manufacturing process, recrystallized grains were adjusted by solution treatment.

As evaluation items for lead frame materials and spring materials,
Strength and elongation were determined by tensile test, bendability was determined by 90" repeated bending test, and the number of bends until breakage was measured, with one round trip being counted as one. Conductivity (heat dissipation) was determined by conductivity (%IACS).
It was shown by Soldering speed is 230 using vertical dipping method.
The solder wetting condition was evaluated by immersing it in a solder bath (60% tin, 40% lead) for 5 seconds at ±5° C. and visually observing the wetting state of the solder. Plating adhesion was evaluated by applying Ag plating to a thickness of 3 μm to a sample, heating it at 450° C. for 5 minutes, and visually observing the presence or absence of blisters occurring on the surface. Heat resistance is 5
When annealed for minutes, the annealing temperature is shown to give 80% of the hardness before annealing.

The spring properties were evaluated by measuring the spring limit value (Kb). These results are shown in Table 1.

The present invention alloy and comparative alloy will be explained below.

Inventive alloy No. 1.4.7.9.11 is based on the basic components of the present invention, and has excellent strength (>57 kgf/■2), electrical conductivity (>50%lAc5), and bending workability. In addition, other properties are also good.

No. 2.3.5.6.8, 1O is a material in which a subcomponent is added to a basic component system, and provides good characteristics similar to those of the basic component system.

Comparative alloys No. 12 and No. 14 do not have sufficient amounts of Sn, respectively, and therefore are inferior in strength, spring characteristics, and heat resistance compared to the alloys of the present invention.

No., 13 has 1 Cr, 15 has 1 Sn,
5wt% and t,owt%, both alloys have inferior conductivity compared to the alloy of the present invention. Furthermore, No
, No. 13 have poor solderability and plating adhesion. No
, 16.17 does not contain Ni, so its bending workability is inferior to that of the alloy of the present invention.

[Effects of the Invention] As detailed above, the alloy of the present invention has excellent properties such as strength, conductivity, heat resistance, and bending workability. Therefore, the alloy of the present invention is suitable for conductive spring materials such as lead frames and terminals of semiconductor integrated circuits, connectors, relays, switches, etc.

Claims (2)

[Claims] (1) Cr0.05-1.5wt%, Sn0.28-1
．． 0 wt%, Ni 0.01 to less than 0.2 wt%,
A high-strength, high-conductivity copper alloy for electronic devices, characterized in that the remainder consists of Cu and unavoidable impurities. (2) Cr0.05-1.5wt%, Sn0.28-1
．． 0 wt%, less than 0.01 to 0.2 wt% Ni, and further one or more selected from the group consisting of Al, Be, Hf, In, Ti, and Zr as subcomponents in a total amount of 0.01
A high-strength, high-conductivity copper alloy for electronic devices, characterized in that it contains Cu and unavoidable impurities.