JPH0230727A - Copper alloy having high-strength and high-conductivity for semiconductor equipment lead material or conductive spring material - Google Patents

Abstract

PURPOSE:To obtain a Cu alloy for conductive spring material suitable for semiconductor equipment member by incorporating specific amounts of Mn and P and further specific auxiliary materials to Cu minimal in the contents of impurities such as oxygen and sulfur. CONSTITUTION:The title copper alloy is obtd. by incorporating 0.5-4.0wt.% Mn and 0.05-1.0wt.% P so that the value of P/Mn is 0.1-0.5, to Cu with high- purity quality in which the contents of oxygen and sulfur as impurities are limited to <=0.0020wt.% and <=0.0015wt.%, respectively, and further, 0.001-3.0wt.%, in total, of one or >=2 elements among Zn, Sn, As, Cr, Mg, In, Sb, Fe, Co, Al, Ti, Zr, Be, Ag, Pb, B, Ni, Si, Hf, Te, and Ga are incorporated as auxiliary materials to the above Cu. A hot rolled plate of the above Cu alloy is subjected to solution heat treatment, to cold rolling, and further to heat treatment at 700-800 deg.C to undergo grain size regulation to <=0.020mm, by which a Cu alloy material excellent in strength, bendability, solderbility, plating suitability, etc., and suitable for semiconductor equipment lead material or conductive spring material can be obtained.

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

[Prior art and problems]

Conventionally, lead materials for semiconductor devices have been Kovar (Fe-29Ni-16Go) and 42 alloy (F
High nickel alloys such as e-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 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 lead is plated with precious metal on the surface.

Good plating adhesion with these precious metals.

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

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

(8) Tin or solder plating does not peel off even when heated for a long time (heat-resistant peelability of plating).

(9) The price is 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, 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 for both semiconductor device lead materials and conductive spring materials. However, it has poor bendability, soldering properties, and plating properties. However, the etching properties and heat-removability of the plating were not fully satisfactory and needed to be improved.

The present inventors investigated various factors for improving strength and deteriorating these properties, and found that the causes of deteriorating properties were coarsening of the crystal grains of the alloy and oxides and sulfides of Mn. The bendability can be improved by adjusting the , and further by limiting the content of 0 and S in the alloy.

It has been discovered that these properties can be improved.

In addition, Zn is added as a subcomponent to the Cu-Mn-P alloy.
, Sn, As, Cr, Mg, In, Sb, Fe, G0.
A1. Ti, Zr, Be, Ag, Pb, B, Ni, Si
By adding one or two of Hf, Te, and Ga, it is possible to obtain strength equal to or higher than that of phosphor bronze for springs, improve bendability, and further improve plating heat peeling resistance. This is what I discovered.

That is, the present invention provides M n 0 , 5-4, Ow
t%, P O, 05 to 1.0 wt%, and Mn
The weight ratio of P/Mn is 0.1 to 0.5, and further contains Zn, Sn, As, Cr, Mg, In,
Sb, Fe, C0. Al, Ti, Zr, Be, Ag, P
A semiconductor device lead characterized by containing one or more of B, B, Ni, Si, Hf, Te, and Ga in a total amount of 0.001 to 3.0 wt%, with the balance being Cu and inevitable impurities. High-strength, high-conductivity copper alloy for material or conductive spring material and M n 0 .

5 to 4.0 wt%, P O, 05 to 1.0 wt%, and the weight ratio of Mn and P is P/Mn of 0.1 to 0.5.
and further contains Zn, Sn, and As as subcomponents.

Cr, Mg, In, Sb, Fe, G0. A1, Ti, Z
r, Be, Ag, Pb, B, Ni, Si, Hf, Te,
One or more types consisting of Ga in a total amount of 0.001-3
．． Among high-strength, high-conductivity copper alloys and impurities for semiconductor device lead materials or conductive spring materials that contain 0 wt%, the balance consists of Cu and unavoidable impurities, and have a crystal grain size of 0.020 m or less. The content of is 0.0020wt
% or less, the high-strength, high-conductivity copper alloy for semiconductor device lead material or conductive spring material as described above, and the impurity, characterized in that the content of S is 0.0015 wt% or less. The present invention relates to the high-strength, high-conductivity copper alloy for use in semiconductor device lead materials or conductive spring materials as described above.

[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 an intermetallic compound such as M n 2P by performing aging treatment after solution treatment to improve strength without reducing conductivity. The reason for adding 0.5 to 4 OL w t% is
At less than 0.5 wt%, no improvement in strength was observed, and 4.0
This is because if it exceeds wt%, the conductivity and workability will decrease.

Similarly, P is an element that improves strength without reducing conductivity by co-adding with Mn and precipitating as an intermetallic compound, but the reason for adding 0.05 to 1.0 wt% is that At less than .05 wt%, no improvement in strength was observed;
．． This is because if it exceeds 0 wt%, the conductivity and workability will decrease.

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

Furthermore, as subcomponents, Zn, Sn, As, Cr, Mg,
In, Sb, Fe, G0. Al, Ti.

Zr, Be, Ag, Pb, B, Ni, Si, Hf, Te
, one or more types consisting of Ga 0. O01-3.
The reason for adding 0wt% is to improve the strength, but if it is less than 0.001wt%, there is no effect, and 3.0w
This is because if it exceeds t%, the conductivity and workability will decrease.

Especially among these subcomponents, Mg, B, Ni, C01Z
r, Ag, and Cr are elements that refine crystal grains and strengthen grain boundaries to improve bendability, and addition of these elements improves strength and bendability.

In addition, Zn, Ni, C0. Ga is an element that not only improves strength but also improves heat-resistant peelability of tin and solder plating.

The reason why the crystal grain size is set to 0.020 ma+ or less is that if the crystal grain size exceeds 0.020 m, the bendability will be significantly deteriorated.

Note that when selecting heat treatment conditions that change the grain size due to aging treatment or strain relief annealing, the grain size after heat treatment should be set to 0.
020m or less.

The reason for setting the ○ content to 0.0020 wt% or less is that when ○ exists, Mn easily combines with oxygen and easily becomes an oxide, becoming so-called inclusions that exist in steel. If it exceeds 0.0020 wt%, a large number of inclusions will be formed, and the bending properties, soldering properties, plating properties, and etching properties will be 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 alloys of the present invention shown in Table 1 were melted and cast using electric steel or oxygen-free 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. 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 m, and then subjected to solution treatment at 800°C for 1 hour, and then cold-rolled to a thickness of 1.51 mm. . This is 70
The crystal 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 m. This is 350
It was heat treated at ℃ for 2 hours and used as 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 performing 90° reciprocating bending using a bending jig with a bending radius of 0.3 mm, 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 state of solder wetting was evaluated visually. Plating adhesion was determined by applying Ag plating to a thickness of 3 μm to a sample, heating it at 450°C for 5 minutes, and visually checking for any blisters that occur on the surface.
Evaluation was made by observing the following four points.

Plating heat peeling resistance was determined by applying 63n/4Pb solder hot-dip plating to the test material, heating it in a constant temperature bath at 150°C for 1000 hours, taking it out every 100 hours, performing 906 bending back and forth once, and checking for peeling of the plating at the bent part. .

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, solderability, plating properties, and heat peeling resistance of plating, and has excellent properties as a high-strength, high-conductivity copper alloy.

〔effect〕

In this way, the alloy of the present invention adds subcomponents to the Cu-Mn-P alloy, limits the grain size during solution treatment or intermediate annealing before aging treatment, and limits O and S as impurities. As a result, the strength was improved, and the bendability, soldering properties, plating properties, etching properties, and heat-removability of the plating were significantly improved.

It is a suitable material for lead materials and conductive spring materials for semiconductor devices, which are desired today.

Claims (4)

[Claims] (1) 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, and further contains Zn, Sn, and A as subcomponents.
s, Cr, Mg, In, Sb, Fe, Co, Al, Ti
, Zr, Be, Ag, Pb, B, Ni, Si, Hf, T
e, one or more types consisting of Ga in a total amount of 0.001
A high-strength, high-conductivity copper alloy for use in semiconductor device lead materials or conductive spring materials, characterized in that it contains ~3.0 wt%, with the remainder consisting of Cu and unavoidable impurities. (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, and further contains Zn, Sn, and A as subcomponents.
s, Cr, Mg, In, Sb, Fe, Co, Al, Ti
, Zr, Be, Ag, Pb, B, Ni, Si, Hf, T
e, one or more types consisting of Ga in a total amount of 0.001
A high-strength, high-conductivity copper alloy for use in semiconductor device lead materials or conductive spring materials, comprising ~3.0 wt%, the remainder consisting of Cu and unavoidable impurities, and having a crystal grain size of 0.020 mm or less. (3) Among impurities, the content of O is 0.0020wt%
A high-strength, high-conductivity copper alloy for a semiconductor device lead material or a conductive spring material according to claim 1 or 2, characterized in that: (4) Among impurities, the content of S is 0.0015wt%
A high-strength, high-conductivity copper alloy for a semiconductor device lead material or a conductive spring material according to each of claims 1 to 3, characterized in that: