JPS63149345A - High strength copper alloy having high electrical conductivity and improved heat resistance - Google Patents

Abstract

PURPOSE:To manufacture a high strength Cu alloy having high electrical conductivity and improved heat resistance by adding specified percentages of Ni, Si and B to Cu. CONSTITUTION:A Cu alloy consisting of 0.4-4.0wt% Ni, 0.1-1.0wt% Si, 0.001-0.1wt% B and the balance Cu with inevitable impurities is manufactured. The alloy may further contain 0.001-3.0wt% in total of one or more kinds of elements selected among Zn, P, Sn, As, Cr, Mg, Mn, Sb, Fe, Co, Al, Ti, Zr, Be, Ag, Pb and lanthanoids as secondary components and the amt. of O among the impurities is restricted to <=0.020wt%. A high strength Cu alloy having high electrical conductivity and suitable for use as a lead material for a semiconductor device or an electrically conductive spring material is obtd.

Description

[Detailed Description of the Invention] [Object] The present invention relates to a copper alloy suitable for lead materials for semiconductor devices such as transistors and integrated circuits (1C), and conductive spring materials for connectors, terminals, relays, switches, etc. be.

[Prior art and problems]

Conventionally, lead materials for semiconductor devices include Kovar (Fe-29Ni-16Co) and 42 alloy (Fe-29Ni-16Co), which have a low coefficient of thermal expansion and have good adhesion and sealing properties with elements and ceramics.
High nickel alloys such as Fe-42Ni) 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 unit 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) Due to the addition of various heating processes 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 with 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 must be low.

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.

However, brass has inferior strength and spring characteristics;
Nickel silver and phosphor bronze, both of which have excellent spring properties, contain 18% by weight of Ni and 8% by weight of Sn. It was an expensive alloy with additional restrictions. 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.

[Points to solve the problem]

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

In particular, the aim is to improve Cu-Ni-Si alloys and provide copper alloys that meet the requirements.

That is, although the Cu-Ni-5i alloy has both excellent conductivity and strength, it is inferior in strength and corrosion resistance when compared to high-strength copper alloys such as beryllium steel and titanium copper.

The present inventors conducted intensive research and found that Cu-N i
It has been found that heat resistance is improved by adding B to the -Si alloy.

[Structure of the invention]

The present invention includes: (1) Ni0.4-4.0wt%, Si0.1-1.0
wt%, B0. Contains 1 to 0.1 wt% of OO, the balance is Cu
A high-strength, high-conductivity copper alloy with improved heat resistance and unavoidable impurities.

(2) Ni0.4-4.0wt%, Si0.1-1.0
wmu%, B0. Contains 1 to 0.1 wt% of OO, and further contains Z0. P, S0. As, Cr, MglM0
．． Sb, Fe, C0. A1. Ti, Zr, Be, Ag,
The total amount of one or more of Pb and lanthanoid elements is 0. A high-strength, high-conductivity copper alloy with improved heat resistance, containing ~3.0 wt% of OOL and the balance being Cu and unavoidable impurities.

(3) Ni 0.4-4.0 wt%, Si 0.1-1.
0wt%, B0. Contains 1 to 0.1 wt% of OO, the remainder C
It is characterized in that the content of O among the impurities is 0.0020 wt% or less. High-strength, high-conductivity copper alloy with improved heat resistance.

(4) Ni0.4-4.0wt%, Si0.1-1.0
wt%, 80.001 to 0.1 wt%, and further contains Z0. P, S0. As.

Cr, Mg%M0. Sb, Fe, C0. A1. Ti,Z
Contains one or more of r, Be, Ag, Pb, and lanthanide elements in a total amount of 0.001 to 3.0 wt%, with the balance consisting of Cu and inevitable impurities, of which the content is 0. A high-strength, high-conductivity copper alloy with improved heat resistance, characterized in that 0°0020 wt% or less.

As a semiconductor device lead material or a conductive spring material,
It features a Cu-Ni-Si alloy that has excellent conductivity and strength, as well as excellent heat resistance, and has significantly improved bendability, solderability, plating performance, and etching performance. It is something.

[Detailed description of the invention]

Next, the reason for limiting the alloy components constituting the alloy of the present invention will be explained.

This is because Ni is co-added with Si in Cu and precipitated as intermetallic compounds such as Ni and Si by performing aging treatment after solution treatment to improve strength without reducing conductivity. The reason for adding 0.4 to 4.0 wt% is that 0.4
No improvement in strength was observed at less than 4.0 wt%.
This is because conductivity and workability will deteriorate if it exceeds this range.

Similarly, Si is an element that improves strength without reducing conductivity by co-adding with Ni and precipitating as an intermetallic compound, but the reason for adding 0.1 to 1.0 wt% is as follows.
At less than 0.1 wt%, no improvement in strength was observed;
This is because if it exceeds wt%, the conductivity decreases, and the soldering properties and workability deteriorate. Desirably, the addition amount ratio of Ni and Si is as follows.

Close to the composition of intermetallic compound (Ni2Si) (Ni/5i
)=(4/l) is good.

B is an additive element that improves strength and heat resistance, but the reason why the amount added is 0.001 to 0.1 wt% is 0.00
If it is less than 1wt%, the strength and heat resistance will not improve, so there is no effect of adding it, and if it exceeds 0.1wt%, sufficient strength and heat resistance can be obtained, but the conductivity will decrease and the solderability will deteriorate. It's for a reason. Furthermore, Z0. P, S0
．． As, Cr, Mg, M0. Sb, Fe, C0. A1,
0.001 to 3°0 wt% of one or more of Ti, Zr, Be, Ag, Pb, B, and lanthanoid elements
The purpose of adding is to improve the strength, but 0.0
If it is less than 0.01 wt%, there will be no effect, and if it exceeds 3.0 wt%, the conductivity and workability will deteriorate. Combine to form oxides.

They become so-called inclusions that exist in steel,
This is because if the O content exceeds 0.0020% by weight, a large number of inclusions will be formed, and the bendability, soldering properties, plating properties, and etching properties will be significantly reduced.

〔effect〕

In this way, the present alloy improves heat resistance by adding B to the Cu-Ni-8i alloy, and by limiting 0 as an impurity, it improves bendability and solderability, which have been the drawbacks of this alloy until now. The adhesion properties, plating properties, and etching properties can be significantly improved.

In addition, 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 a suitable material for lead materials and conductive spring materials for semiconductor devices, and none of the prior art alloys has such comprehensive properties.

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

〔Example〕

Ingots having various compositions of the alloys of the present invention shown in Table 1 were melted and cast using electrolytic copper or non-wire copper as raw materials in a high-frequency melting furnace in air, an inert atmosphere, or a reducing atmosphere. If electrolytic copper is used, it is recommended to dissolve it in a reducing atmosphere to reduce the oxygen content.

Next, this was hot rolled at 900°C to form a plate with a thickness of 4 mm, and then solution treatment was performed at 900°C for 5 minutes, solidified, and cold rolled to a thickness of 0.3 nn. .

This was subjected to aging heat treatment at 400° C. for 2 hours to obtain a test material. 5 strength as evaluation items for lead material and spring material,
Elongation was evaluated by a tensile test, and springiness was evaluated by Kb value. 6 Electrical conductivity (heat dissipation) is electrical conductivity (%IAC8)
It was shown by 1.1 Thermal properties are shown as the temperature at which the hardness becomes 80% of the hardness before annealing (softening temperature) when annealed for 5 minutes.

The bendability is bending R0. Using a 3rra bending jig, perform 90° reciprocating bending and calculate the number of times until breakage.
I decided.

Soldering is done using the vertical immersion method in a solder bath at 230±5℃ (
The solder was immersed in a solution (60% tin, 40% lead) for 5 seconds, and the wetting state of the solder was visually observed. Plating adhesion was determined by applying Ag plating with a thickness of 3μ to the sample and testing it at 450°C for 50 minutes.
The sample was heated for 1 minute and evaluated visually for the presence or absence of blisters generated on the surface. These results are shown in Table 1 along with comparative alloys.

From this table, the alloy of the present invention is a high-strength, high-conductivity copper alloy that has improved heat resistance, improved soldering properties, plating properties, etching properties, and bending properties in addition to high strength and electrical properties. It is clear that it has excellent properties as

Claims (4)

[Claims] (1) Ni0.4-4.0wt%, Si0.1-1.0
wt%, B0.001 to 0.1 wt%, the balance Cu
A high-strength, high-conductivity copper alloy with improved heat resistance and unavoidable impurities. (2) Ni0.4-4.0wt%, Si0.1-1.0
wt%, B0.001 to 0.1 wt%, and further contains Zn, P, Sn, As, Cr, Mg, Mn as subcomponents.
, Sb, Fe, Co, Al, Ti, Zr, Be, Ag,
A high-strength, high-conductivity copper alloy with improved heat resistance, containing one or more of Pb and lanthanide elements in a total amount of 0.001 to 3.0 wt%, and the balance being Cu and unavoidable impurities. (3) Ni0.4-4.0wt%, Si0.1-1.0
wt%, B0.001 to 0.1 wt%, the balance Cu
A high-strength, high-conductivity copper alloy with improved heat resistance, characterized in that the content of O among the impurities is 0.0020 wt% or less. (4) Ni0.4-4.0wt%, Si0.1-1.0
wt%, B0.001 to 0.1 wt%, and further contains Zn, P, Sn, As, Cr, Mg, M as subcomponents.
n, Sb, Fe, Co, Al, Ti, Zr, Be, Ag
, Pb, and lanthanide elements in a total amount of 0.001 to 3.0 wt%, and the remainder consists of Cu and unavoidable impurities, and the content of O among the impurities is 0.0020 or less A high-strength, high-conductivity copper alloy with improved heat resistance.