JPH01162737A - Copper alloy for electronic parts - Google Patents

Abstract

PURPOSE:To provide the subject alloy with excellent electric and heat conductivity, heat resistance and spring characteristics by incorporating specific amounts of Sn to a Cu-Zn alloy having specific compsn. CONSTITUTION:The compsn. of the copper alloy for electronic parts is constituted of, by weight, 3-20% Zn, 0.1-4.0% Sn, or furthermore of 1-15% Ni and the balance Cu with inevitable impurities. If necessary, one or more kinds selected from the group of 0.001-2.0% Cr, Co, Zr, Be, As, P, Pb, Si, Ti, Mn, Mg, Fe and Al are furthermore incorporated thereto as the secondary components. Said copper alloy has more excellent strength, solderability, stress relaxation characteristics, corrosion resistance and SCC resistance than red brass which is the lower spring material and has the specific value not inferior to that of German silver and phosphor bronze.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a copper alloy for electronic parts such as lead materials, connectors, terminals, relays, switches, etc. of semiconductor devices such as transistors and integrated circuits (ICs). be.

[Prior Art] Conventionally, as lead materials for semiconductor devices, Kovar (Pc-29Ni-IGco) and 42 alloy (Fe
-42Ni), gold has been preferred for high nickel. However, in recent years, as the degree of integration of semiconductor fIiH circuits has improved, there has been an increase in the number of ICs with low power consumption, resins are often used as sealing materials, and there have been improvements in 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.

In addition, conventional springs for electrical equipment, springs for measuring instruments, switches,
As materials for springs used in connectors and the like, inexpensive brass, nickel silver, which has excellent spring properties and corrosion resistance, or phosphor bronze, which has excellent spring properties, have been used.

[Problems to be Solved by the Invention] In general, lead materials for semiconductor devices are required to have the following characteristics.

(1) Leads must exhibit excellent thermal and electrical conductivity, as they are required to act as an electrical signal transmission unit and also have the function of discharging heat generated during the unpacking process and circuit use to the outside. .

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

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

(4) Most leads are manufactured by punching or bending lead material, so the processability 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 leads, so good soldering is a sign of good soldering.

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

(8) The price is paper storage.

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, brass, which has traditionally been used as a spring material, has poor strength and spring properties, and nickel silver, which has excellent strength and spring properties,
As for phosphor bronze, nickel silver contains 18% by weight of Ni, and phosphor bronze contains 8% by weight of Sn, making it an expensive alloy due to constraints on raw materials and manufacturing, 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] The present invention has been made in view of the above points, and improves the drawbacks of conventional copper-based alloys and provides various properties suitable for lead materials and conductive spring materials for semiconductor devices. The present invention aims to provide a copper alloy for electronic parts having the following properties.

That is, in the present invention, the Z content is 3% or more and less than 20% by weight.
n, a copper alloy containing 0.1 to 4.0% Sn, or further containing 1 to 15% Nt, the balance containing Cu and unavoidable impurities, or further containing 01% Co5Zr as a subcomponent.

Be, As, P, Pb5S t, 'rt, Mn.

M g SF e s A 1 each 0.001 to 2.0
o, oot one or more types selected from the group width of %
It is a copper alloy containing ~2.0%, and has excellent electrical and thermal conductivity and heat resistance as a semiconductor device lead material or conductive spring material.
This material not only has spring properties, but also has good solderability, plating properties, etching properties, and bendability.

The reasons for limiting the components and component ratios of the copper alloy for electronic components according to the present invention will be explained.

Cu and Zn are the basic components of the material of the present invention, and improve processability,
Improves mechanical properties and processability.

The reason why the Zn content is set to 3% or more and less than 20% is that if the Zn content is less than 396, it is not effective in improving the strength.
This is because if the content exceeds 0%, the soldering properties will deteriorate. Preferably, containing 10% or more of Zn has higher strength and is less expensive.

Sn is an element that improves strength, corrosion resistance, and stress corrosion cracking resistance, and the reason why the Sn content is set to 0.1 to 4.0% is that if it is less than 0.1%, there is almost no effect.
%, hot workability becomes difficult and the price becomes high. In order to improve corrosion resistance and stress corrosion cracking resistance, it is desirable to contain 100% or more of Sn.

Ni is an element that improves strength, stress relaxation properties, corrosion resistance, and stress corrosion cracking resistance.The reason why the Ni content is set to 1 to 15% is that if the Ni content is less than 1%, there is little effect; This is because, if it exceeds this value, workability and soldering properties will deteriorate and the price will increase.

In addition, subcomponents of Cr, Co, Zr, and Be.

As, P, PbS　S　i, T　iSMn, Mg.

Fe and AI are added as deoxidizing agents or elements that improve strength, and one or more of them are added from the group of 0.001 to 2.0% each in an amount of o, oot to 2.0%. The reason for this is that if it is less than 0.0%, there is no effect, and if it exceeds 2.0%, the strength will improve, but the workability and soldering properties will deteriorate.

〔Example] Next, the present invention will be explained in detail.

An alloy having the composition shown in Table 1 was melted, hot rolled, appropriately cold rolled, and annealed repeatedly, and after final rolling to a plate thickness of 0.251, strain relief annealing was performed. Then pickling #1
After polishing with 200mm merry paper and degreasing, the properties required for lead and spring materials are tensile strength, elongation, spring limit value, electrical conductivity, repeated bendability, stress relaxation properties, solderability, corrosion resistance, and The stress corrosion cracking resistance was investigated.

The results are also listed in Table 1.

Tensile strength and elongation were evaluated using a JISS No. tensile test piece and a Tensilon type tensile tester. The spring limit value was determined using a test piece processed into a rectangular shape with a width of 10 nua, and a test piece of 0.1 m.
The bending stress that causes permanent deformation of ll1 was determined. The conductivity was expressed in units of %lAC3.

Repeated bendability was determined by attaching a 225 g weight to one end of a test piece processed into a terminal shape with a width of 0.51, performing 90° reciprocating bending, and determining the number of times until breakage as 1411+. The stress relaxation property was determined by applying 0.2% to a test piece processed into a strip shape with a width of 10 rgs.
A bending stress of 80% of the yield strength was applied, and the stress relaxation rate was measured after heating at 150° C. for 500 hours.

For soldering, use rosin-methanol as a flux in an 8Sn/4Pb solder bath at 230°C, and polish the surface with #1200 hardened merry paper to a polished test piece (0
, 25'XIP

Corrosion resistance: 35°C, humidity 9 containing 25ppH SO2
A test piece (0,25' x 40° x 60
1) was exposed for 196 hours and the appearance was observed.

Stress corrosion cracking resistance (SCC resistance) was investigated in an ammonia atmosphere using the Thompson method.

The method is to prepare a test piece (0,25' x 12.P x 150'
) to form a loop, and after 24 hours, 1
A desiccator containing 4 to 6 ammonia water was exposed to mist, and the time required for cracking to occur was investigated.

All of these test pieces were taken parallel to the rolling direction. From this table, the alloy of the present invention has better strength, solderability, stress relaxation characteristics, corrosion resistance, and SC resistance than red copper, which is a low-grade spring material.
It can be seen that this is an inexpensive copper alloy for electronic parts that has excellent C properties and comparable properties to expensive nickel silver and phosphor bronze.

[Effects of the Invention] The copper alloy of the present invention contains Sn or roughly Ni in red copper (Cu-Zn alloy) conventionally used as a low-grade spring material.
This is an inexpensive copper alloy for electronic components with improved strength, solderability, stress relaxation properties, corrosion resistance, and stress corrosion cracking resistance.

Claims (1)

[Claims] (1) Zn of 3% or more and less than 20% by weight, 0.1 to 4
．． A copper alloy for electronic parts, characterized in that it contains 0% Sn, and the balance consists of Cu and inevitable impurities. (2) Zn of 3% or more and less than 20% by weight, 0.1 to 4
．． Contains 0% Sn, and further contains Cr, Co,
Zr, Be, As, P, Pb, Si, Ti, Mn, Mg
, Fe, Al, each 0.001 to 2.0% of one or two selected from the group
1. A copper alloy for electronic components, characterized in that it contains 0.001 to 2.0% of Cu and the remainder is Cu and inevitable impurities. (3) Zn of 3% or more and less than 20% by weight, 0.1 to 4
．． A copper alloy for electronic parts, characterized by containing 0% Sn, 1 to 15% Ni, and the balance consisting of Cu and inevitable impurities. (4) Zn of 3% or more and less than 20% by weight, 0.1 to 4
．． Contains 0% Sn, 1-15% Ni, and further contains Cr, Co, Zr, Be, As, P, Pb, Si as subcomponents.
, Ti, Mn, Mg, Fe, Al each from 0.001 to 2.
0% of one or more species selected from the group 0.00
A copper alloy for electronic parts, characterized in that it contains 1 to 2.0% Cu, and the remainder consists of Cu and unavoidable impurities.