JPH01139742A - Manufacture of high-strength and high-conductivity copper alloy - Google Patents

Abstract

PURPOSE:To obtain a high-strength and high-conductivity copper alloy excellent in strength and toughness by subjecting a Cu alloy containing specific amounts ot Cr and Zr or further other elements to hot rolling, cold working, and heat treatment under respectively specified conditions. CONSTITUTION:An ingot, etc., of Cu alloy which has a composition containing, by weight, 0.1-1.5% Cr and 0.05-1.0% Zr or further containing 0.01-1.0% Si or one or >=2 elements among Al, Be, Fe, Hf, Mg, Ni, P, Sn, Ti, and Zn independently or in combination are heated at 850-1000 deg.C for 0.5-5.0hr and hot-rolled. Directly after the above hot rolling, the resulting hot-rolled stock is cooled at >=1 deg.C/sec cooling rate and cold-worked into the desired shape and then subjected to annealing at 300-600 deg.C for 0.5-20hr, successively to finish cold working, and to annealing treatment for relieving stress established at the time of the above working, by which the high-strength and high-conductivity copper alloy excellent in strength and toughness can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides 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. Regarding the manufacturing method of the material, the present invention provides a high-strength, high-conductivity alloy that is particularly strong and has excellent toughness.

[Conventional technology] Conventional lead materials for semiconductor devices have a low coefficient of thermal expansion;
High nickel alloys such as Kovar (Fe-29Ni-16Co) and 42 alloy have been preferably used because of their good adhesion and sealing properties with elements and ceramics. However, in recent years,
With the increase in the degree of integration of semiconductor circuits, many ICs with high power consumption have come into use, and more resins have been used as sealing materials, and improvements have been made to the bonding between elements and lead frames. As a result, copper alloys with good heat dissipation properties have come to be used as lead materials.

Furthermore, as materials for springs conventionally used for electrical equipment springs, measuring instrument springs, switches, connectors, etc., inexpensive brass, nickel silver with excellent spring properties and corrosion resistance, or phosphor bronze with excellent spring properties have been used. was.

[Problems to be Solved by the Invention] Generally, 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 packaging process and circuit use.

]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, processing, or bending the lead material, so the workability of these materials must be 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;
Since many items are soldered to the so-called outer lead parts, good soldering must be demonstrated.

('?1) Good corrosion resistance from the viewpoint of equipment reliability and service life.

(B) With the transition from the DIP type to the QIJad type, future lead materials will be required to have less anisotropy.

(9) The price must be low.

Oxygen-free copper, tin-containing copper, phosphor bronze, Kovar, and 42 alloy, which have been conventionally used to meet these various required characteristics, all have advantages and disadvantages, and cannot necessarily satisfy all of these characteristics.

Brass used as a spring material has poor strength and spring properties, and nickel silver and phosphor bronze, which have excellent strength and spring properties, contain 18% Ni by weight for nickel silver and 8% Sn by weight for phosphor bronze.
This made it an expensive alloy due to the 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 conductivity is good,
The advent of an inexpensive alloy with excellent spring properties was awaited.

Although the Cu-Cr-2r alloy satisfies the above-mentioned required properties, its strength is inferior to that of the 42 alloy and phosphor bronze.

Means for Solving Problem 1] The present invention has been made to solve the above problems,
The present invention aims to improve the drawbacks of CtJ-Cr-Zr alloys and to provide a copper alloy that has properties suitable for use as lead materials for semiconductor devices, conductive spring materials, and the like.

Although it is possible to improve the strength of the Cu-Cr-Zr system by changing the component composition,
Changing the component composition is undesirable because various properties such as conductivity and bendability deteriorate.

The present invention has discovered a new manufacturing method in order to improve only the strength while maintaining the excellent mechanical properties of the Cu-Cr'-Zr alloy as described above.

That is, in the first invention, 0.1 to 1.5% by weight of Cr
(III) In a method of hot working, cold working, and annealing an alloy containing 0.05 to 1.0% by weight of Zr and the balance consisting of Cu and unavoidable impurities,
After heating for 5°0 hours, hot rolling is performed, and immediately after hot rolling, the workpiece is cooled at a rate of 1°C/see or more. (n) After cooling, cold working is performed by 50% or more, and processing is performed. 3 pieces of wood
Annealing at a temperature of 0.00 to 600"C for 0.5 to 20.0 hours; (III) After annealing, cold working and further strain relief annealing; (III) to (I[I) above; This is a method for manufacturing a high-strength, high-conductivity copper alloy, which is characterized in that the steps are performed sequentially.

Further, a second invention is one in which the alloy composition further includes 0.01 to 1.0% by weight of Si in the first invention, and
In the first invention, the invention further includes Al in the alloy composition.
, Be, Co, Fe, HfSHg, Ni.

The fourth invention is one that contains one or more selected from the group consisting of P, Sn, Ti, and 70 in a total amount of 0.01 to 1.0% by weight, and the fourth invention is the first invention,
Si 0.01 to 1.0% by weight of the second invention and Al, Be, Co, Fe, Hf, )l(1, N
i, P, Sn.

It simultaneously contains one or more selected from the group consisting of Ti and Zn in a total amount of o, oi to 1.0% by weight, and all of them are used in each step of hot working, cold working, and annealing. is the same as the first invention.

The reasons for limiting the alloy components as described above in each invention are as follows.

The reason why the Cr content is set to 0.1 to 1.5% by weight is that precipitation hardening due to fine Cr grains can be expected and heat resistance associated with this can be obtained. Cr content is 0.1
If it is less than 1.5% by weight, the above-mentioned effects cannot be expected, and if it exceeds 1.5% by weight, the processability and conductivity will be significantly reduced.
The reason why the content of zr is set to 0.05 to 1.0% by weight is that the solderability also decreases.
This is to promote precipitation hardening and obtain heat resistance associated with it. If the Zr content is less than 0.05% by weight, the above-mentioned effects cannot be expected, and conversely, if it exceeds 1.0% by weight, workability,
This is because the conductivity decreases significantly.

The reason why the Si content is set to 0.01 to 1.0% by weight is as follows.
This is to promote precipitation hardening and obtain heat resistance associated with it. This is because if the Si content is less than 0.01% by weight, the above-mentioned effects cannot be expected, whereas if it exceeds 1.0% by weight, the conductivity will be significantly lowered and the solderability will also be lowered.

Furthermore, Al, Be5Co, Fe, Hf, Hg, N
i, P.

The addition of one or more selected from the group consisting of sn, r; and ln is expected to have the effect of improving strength and heat resistance without significantly reducing electrical conductivity. Therefore, the reason why the total amount of content should be at least 1.0% by weight is that if the content is less than 1.0% by weight, the above-mentioned effect cannot be expected, and if it exceeds 1.0% by weight, the conductivity will decrease. This is because the amount decreases significantly.

Moreover, the reasons for limiting the conditions in manufacturing steps (1) to (I[I) are as follows.

In step (I>), the temperature is 850 to 1000°C.
After heating for 5 to 5.0 hours, hot rolling is performed, and the reason for cooling the workpiece at a rate of 1°C/sec or more immediately after the hot rolling is completed is to obtain excellent strength and conductivity, and the heating temperature is 8
If the temperature is less than 50°C, a significant decrease in strength will occur, and the
If the temperature exceeds 0°C, a liquid phase may appear in some parts. Also,
If the heating time is less than 0.5 hours, a significant decrease in strength will occur, and if it exceeds 5.0 hours, there will be no economic value.

Furthermore, after hot rolling, the cooling rate of the processed material is 1℃/sec.
This is because if it is less than c, there will be a significant decrease in strength and electrical conductivity.

In step (II), after cooling, cold working is performed by 50% or more, and the processed material is heated to a temperature of 300 to 0.5
The reason for annealing for ~20.0 hours is that it can be expected to improve strength and electrical conductivity.If cold working is performed by less than 50% after cooling, no improvement in strength can be expected due to annealing. ℃ or less than 0.5 hours, no improvement in conductivity can be expected, and even if the temperature exceeds 500℃,
This is because even if the time exceeds 20.0 hours, no improvement in strength can be expected. The most preferable heat treatment conditions are a temperature of 350 to 450°C for 1.0 to 3.0 hours.

In step (III), cold working is performed after annealing because a significant improvement in strength can be expected. The reason why strain relief annealing is performed at the end is that cold working after annealing significantly improves strength, but reduces elongation and deteriorates bendability, so strain relief annealing is performed to improve bendability again. It's for a reason.

[Example] Next, examples of the present invention will be described.

An alloy having the composition shown in Table 1 was melted to obtain an ingot with a thickness of 30 mm, and test materials were produced under the manufacturing conditions shown in Table 1. The tensile strength, elongation, and electrical conductivity of these test materials were measured, and a 90° repeated bending test was conducted.
- The number of bends until breakage was measured, with one round trip. Solderability was evaluated by vertical dipping method by dipping the sample in a solder bath (5N60%, Pb40%) at 230±5° C. for 5 seconds and visually observing the wetting state of the solder.

These results are shown in Table 1 along with comparative alloys.

As is clear from Table 1, the products produced using the manufacturing method of the present invention have improved strength compared to the comparative example, comparable to that of 42 alloy, less anisotropy, and no deterioration in other properties. I know that I won't let you.

[Effects of the Invention] As explained above, according to the present invention, the strength is particularly high;
A high-strength, high-conductivity copper alloy with excellent toughness and no deterioration in other properties can be obtained, and is an excellent alloy material as a material for electronic parts used in semiconductor devices.

Claims (4)

[Claims] (1) Cr0.1-1.5% by weight and Zr0.05-1
．． In a method of hot working, cold working, and annealing an alloy containing 0% by weight and the remainder consisting of Cu and unavoidable impurities,
I) Hot rolling is performed after heating to a temperature of 850°C to 1000°C for 0.5 to 5.0 hours, and immediately after hot rolling, the workpiece is cooled at a rate of 1°C/sec or more, (II) Cooling 50 more
(III) After annealing, cold working is performed and strain relief annealing is performed. A method for producing a high-strength, high-conductivity copper alloy, comprising sequentially performing steps (I) to (III). (2) Cr0.1-1.5% by weight, Zr0.05-1.
In a method of hot working, cold working, and annealing an alloy containing 0% by weight and 0.01 to 1.0% by weight of Si, and the balance consisting of Cu and unavoidable impurities, (I) .5-5.0
After heating for a period of time, hot rolling is performed, and immediately after the hot rolling, the workpiece is cooled at a rate of 1°C/sec or more. (II) After cooling, cold working is performed by 50% or more, and the workpiece is
Annealing at a temperature of 00 to 600°C for 0.5 to 20.0 hours. (III) After annealing, perform cold working and further perform strain relief annealing. The above steps (I) to (III) are performed sequentially. A method for producing a high-strength, high-conductivity alloy. (3) Cr0.1-1.5% by weight and Zr0.05-1
．． 0% by weight and Al, Be, Co, Fe, Hf, Mg,
Hot working an alloy containing a total amount of 0.01 to 1.0% by weight of one or more selected from the group consisting of Ni, P, Sn, Ti, and Zn, and the balance being Cu and unavoidable impurities; In the method of cold working and annealing, (I) 0.5 to 5.0 at a temperature of 850 ° C to 1000 ° C.
After heating for an hour, hot rolling is performed, and immediately after hot rolling, the workpiece is cooled at a rate of 1°C/sec or more. (II) After cooling, the workpiece is cold worked by 50% or more to reduce
Annealing at a temperature of 0 to 600°C for 0.5 to 20.0 hours. (III) After annealing, perform cold working and further perform strain relief annealing. The above steps (I) to (III) are performed sequentially. A method for producing a high-strength, high-conductivity alloy. (4) Cr0.1-1.5% by weight, Zr0.05-1.
0% by weight, Si0.01-1.0% by weight, Al, Be
, Co, Fe, Hf, Mg, Ni, P, Sn, Ti, Z
In a method of hot working, cold working and annealing an alloy containing a total amount of 0.01 to 1.0% by weight of one or more selected from the group consisting of n, the balance being Cu and unavoidable impurities. , (I) 0.5 to 5.0 at a temperature of 850℃ to 1000℃
After heating for an hour, hot rolling is performed, and immediately after hot rolling, the workpiece is cooled at a rate of 1°C/sec or more. (II) After cooling, the workpiece is cold worked by 50% or more to reduce
Annealing at a temperature of 0 to 600°C for 0.5 to 20.0 hours. (III) After annealing, perform cold working and further perform strain relief annealing. The above steps (I) to (III) are performed sequentially. A method for producing a high-strength, high-conductivity alloy.