JPH0219432A - High-strength and high-conductivity copper alloy for semiconductor equipment lead material or conductive spring material - Google Patents

Abstract

PURPOSE:To produce the title high-strength and high-conductivity copper alloy improved in bendability, etc., by specifying the weight ratio between Mn and P contents and grain size, respectively, in a copper alloy containing specific percentages of Mn and P. CONSTITUTION:A copper alloy which has a composition consisting of, by weight, 0.5-4.0% Mn, 0.05-1.0% P, and the balance Cu with inevitable impurities and satisfying P/Mn=0.1-0.5 by weight ratio and in which grain size is regulated to <=0.020mm is prepared. At this time, the contents of O and S among the impurities are regulated to <=0.0020% and <=0.0015%, respectively. By this method, the copper alloy improved in bendability, solderability, plating suitability, and etching characteristic can be obtained. This copper alloy is useful as semiconductor equipment lead material or conductive spring material.

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 (ICs), and conductive spring materials for connectors, terminals, relays, switches, etc. be.

[Prior art and problems]

Conventionally, high nickel materials such as copal (Fa, -29Ni-16Co) and 42 alloy (Fe-42Ni) have been used as lead materials for semiconductor devices because of their low coefficient of thermal expansion and good adhesion and sealing properties with elements and ceramics. Alloys 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) 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 workability of these materials should be good.

(5) The surface of the lead is plated with precious metals, so 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 must be 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, 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 wt% Ni and 8 wt% Sn, so there are also processing constraints such as poor hot workability in terms of raw materials and manufacturing. 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.

[Structure of the invention]

The present invention was made in view of this point, and in particular Cu-
The present invention aims to improve Mn-P alloys and provide copper alloys having various properties suitable for use as lead materials and conductive spring materials for semiconductor devices.

In other words, the Cu-Mn-P alloy exhibits excellent strength and conductivity, and can be said to be an excellent copper alloy as both a semiconductor device lead material and a conductive spring material. , properties, and etching properties were not fully satisfactory and needed improvement.

The present inventors investigated various causes of deterioration of these properties and found that the causes were coarsening of crystal grains of the alloy and oxides and sulfides of Mn. In addition, we aim to improve 0 in the alloy.
．． It has been discovered that the properties can be improved by limiting the S content.

That is, the present invention provides M n 0 , 5-4, Ow
t%, P 0.05 to 1.0 wt%, and
The weight ratio of Mn and P is P/Mn of 0.1 to 0.5, the balance consists of Cu and inevitable impurities, and the crystal grain size is 0.02.
High-strength, high-conductivity steel alloy for semiconductor device lead material or conductive spring material, characterized by having a thickness of 0 mm or less, and Mn of 0.5 to 0.5
4.0 wt%, including P O, 05 to 1.0 wt%,
and the weight ratio of Mn and P is P/Mn of 0°1 to 0.5,
A semiconductor device lead material or a conductive spring material, characterized in that the remainder is Cu and unavoidable impurities, the content of 0 among the impurities is 0.0020 wt% or less, and the crystal grain size is 0.020 nn or less. High-strength, high-conductivity steel alloy and Mn0.5-4.0wt%, PO,05-1.
0wt%, and the weight ratio of Mn and P is P/Mn''1
'0.1 to 0.5, the balance consists of Cu and unavoidable impurities, and among these impurities, the S content is O, OO1'5w
The present invention relates to a high-strength, high-conductivity copper alloy for use in semiconductor device lead materials or conductive spring materials, which is characterized by having a grain size of 0.020 m or less and a crystal grain size of 0.020 m or less.

Not only does it have excellent strength, electrical and thermal conductivity, heat resistance, and spring properties as a semiconductor device lead material or conductive spring material, but it also has excellent bendability, especially when bendability is required in such applications. .

It is characterized by improved soldering properties, plating properties, and etching properties.

[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 Mn is co-added with P in Cu and is precipitated as intermetallic compounds such as M n and P by performing aging treatment after solution treatment to improve strength without reducing conductivity. , M n'jt 0 , 5~4 , Ow
The reason for adding t% is that if it is less than 0.5 wt%, no improvement in strength will be observed, and if it exceeds 4.0 wt%, the conductivity and workability will decrease.

P is also co-added with Mn and is an element that improves the strength of intermetallic compounds, but the reason for adding 0.05 to 1.0 wt% of P is that if it is less than 0.05 wt%, no improvement in strength is observed. First, if it exceeds 1.0 wt%, conductivity and workability will decrease.

The reason why the weight ratio of Mn and P is set to 0.1 to 0.5 in terms of P/Mn is that if it is less than 0.1, no improvement in strength will be observed, and if it exceeds 0.5, a large amount of P will not precipitate as an intermetallic compound. Become,
This is because conductivity and workability decrease.

The grain size is 0. The reason for setting the O20 nm or less is that the crystal grain size is 0. This is because if the thickness exceeds 020 nm, the bending properties will deteriorate significantly.

The reason why the O content is set to 0.0020 wt% or less is that when O exists, Mn easily combines with oxygen, easily becomes an oxide, and becomes so-called inclusions that exist in steel. If the amount exceeds 0.0020 wt%, many inclusions will be generated, which will affect bendability, solderability, plating properties,
This is because the etching properties are significantly reduced.

The reason why the S content is set to 0,0015 wt% or less is that when S exists, Mn is very easy to combine with S, easily becoming a sulfide and existing in steel.
This is because if the amount exceeds .0015 wt%, a large amount of sulfide is produced, and bending properties, soldering properties, plating properties, and etching properties are significantly reduced.

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

〔Example〕

Ingots having various compositions of the alloy of the present invention shown in Table 1 were melted and cast 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. If electrolytic copper is used, it is recommended to dissolve it in a reducing atmosphere to reduce the oxygen content. Regarding S, a copper raw material with an S content of 0.0015 wt% or less was used for the alloy of the present invention.

Next, this was hot-rolled at 800°C to form a plate with a thickness of 6 cm, and then solution treated at 800"CX for 1 hour, with 1 solid agent applied, and then cold-rolled to a thickness of 1.5 mm. I made this 70
The grain size was adjusted by heat treatment at 0° C. to 800° C. for 1 minute to 30 minutes, and then cold rolled to a thickness of 0.3 an. This is 35
It was heat-treated at 0°C for 2 hours to obtain a test material.

As evaluation items for lead materials and spring materials, strength and elongation were evaluated by a tensile test, and springiness was evaluated by Kb value. Electrical conductivity (heat dissipation) was shown by electrical conductivity (%IAC5). The bendability was determined by using a bending jig with a bending radius of 0.3 mm, performing 90° reciprocating bending, and measuring the number of times until breakage.

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

From this table, it is clear that the alloy of the present invention has significantly improved bending properties, soldering properties, and plating properties, and has excellent properties as a high-strength, high-conductivity steel alloy.

〔effect〕

The alloy of the present invention has improved bendability and solderability by adjusting the crystal grain size by solution treatment or intermediate annealing before the aging treatment of the Cu-Mn-P alloy, and by limiting O and S as impurities. , plating properties.

Etching properties were significantly improved. It is a suitable material for lead materials and conductive spring materials for semiconductor devices, which are desired today.

Margin below

Claims (3)

[Claims] (1) Mn0.5-4.0wt%, P0.05-1.0
wt%, and the weight ratio of Mn and P is 0 as P/Mn.
．． 1 to 0.5, the balance being Cu and unavoidable impurities, and having a crystal grain size of 0.020 mm or less. (2) Mn0.5-4.0wt%, P0.05-1.0
wt%, and the weight ratio of Mn and P is P/Mn of 0.
1 to 0.5, the balance is Cu and unavoidable impurities, and among the impurities, the content of O is 0.0020 wt% or less, and the crystal grain size is 0.020 mm or less. High-strength, high-conductivity copper alloy for lead material or conductive spring material. (3) Mn0.5-4.0wt%, P0.05-1.0
wt%, and the weight ratio of Mn and P is P/Mn of 0.
1 to 0.5, the balance consisting of Cu and inevitable impurities,
A high-strength, high-conductivity copper alloy for semiconductor device lead material or conductive spring material, characterized in that the content of s among the impurities is 0.0015 wt% or less and the crystal grain size is 0.020 mm or less.