JPH03191043A - Manufacture of high strength and high conductivity copper alloy for electronic equipment - Google Patents

Abstract

PURPOSE:To obtain the high strength and high conductivity Cu alloy for electronic equipment excellent in strength and toughness by subjecting a Cu-Cr- Ti-Ni-Zn series alloy having a specified compsn. to hot rolling, cold working and annealing under specified conditions into a sheet material and thereafter executing final finish cold working and annealing. CONSTITUTION:A Cu alloy contg., by weight, 0.05 to 1.0% Cr, 0.02 to 0.6% Ti, 0.05 to 1.5% Ni and 0.01 to 3.0% Zn or furthermore contg. one or >=2 kinds among Al, Be, Co, Fe, Hf, In, Mg, Mn, P, Sn, Zr and Si is refined. The ingot of the Cu alloy is heated to 850 to 1000 deg.C for 0.5 to 5.0 hr, is thereafter hot- rolled, is immediately cooled at >=1 deg.C/sec cooling rate, is thereafter subjected to cold working at >=50% draft and is successively annealed at 300 to 600 deg.C for 0.5 to 20 hr. The ingot is furthermore subjected to cold working into a desired sheet material or the like and is subjected to final stress relieving annealing. The Cu alloy having high strength and high toughness suitable for electrical conductive spring materials such as lead wire rods, connectors, terminals, relays and switches of a semiconductor device can be obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a copper alloy material suitable for lead materials for semiconductor devices such as transistors and integrated circuits (ICs), and conductive spring materials for connector terminals, relays, switches, etc. Regarding the manufacturing method of
The present invention provides a high-strength, high-conductivity copper alloy for electronic devices 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-L6Co) and 42 alloy, which have good adhesion and sealing properties with elements and ceramics, have been preferably used. However, in recent years,
As the degree of integration of semiconductor circuits has increased, ICs with high power consumption have come to be used more frequently, and resins have been used more often as sealing materials, and improvements have also been made to the adhesion between elements and lead frames. As a result, copper alloys with good heat dissipation properties have come to be used as lead materials.

In addition, the spring materials conventionally used for electrical equipment springs, mechanical springs, switches, connectors, etc. include inexpensive brass, nickel silver with excellent spring properties and corrosion resistance, and phosphor bronze with excellent spring properties. It was used.

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

(1) The lead must exhibit excellent thermal and electrical conductivity, as it is required to act as an electrical signal transmission part and also to emit heat generated during the balacaging 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) Since most leads are manufactured by punching or bending lead material, the workability of these materials must be good.

(5) Since the surface of the lead is plated with precious metals, the lead must have good plating adhesion to these precious metals.

(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.

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

(g) With the transition from DIP type to Quad type,
Future lead materials will be required to have low anisotropy.

(9) Prices are low.

Oxygen-free copper, tin-containing copper, phosphor bronze, Konokuichiru, and 42 alloys that have been conventionally used to meet these various required characteristics all have advantages and disadvantages, and they cannot necessarily satisfy all of these characteristics. do not have.

In addition, 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% S by weight for phosphor bronze.
Since this alloy contains n, it is an expensive alloy due to constraints on processing such as poor hot workability in terms of raw materials and production. Furthermore, when used for electrical equipment, etc., it has a drawback of low electrical conductivity. Therefore, the conductivity is good,
The emergence of an inexpensive alloy with excellent spring properties has been awaited.

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

[Means for Solving the Problems] The present invention has been made to solve the above problems, and
The present invention aims to improve the drawbacks of Cu-Cr-T i -N 1-Zn alloys and to provide a copper alloy having various properties suitable for use as lead materials for semiconductor devices, conductive spring materials, etc.

It is possible to improve the strength of the Cu-Cr-Ti-Ni-Zn system by changing the component composition, but changing the component composition deteriorates various properties such as conductivity and bendability, which is not preferable. .

The present invention provides Cu-Cr-TiN1-Zn as described above.
A new manufacturing method was discovered in order to improve only the strength while maintaining the excellent properties of the alloy.

That is, the first invention has Cr 0.05 to 1,0νt
%, T i 0.02-0. [i vt%, N i 0
．． 05-1.5 wt% and Z n 0.01-3.0
(I) After heating to a temperature of 850°C to 1000°C for 0.5 to 5.0 hours, 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 to a temperature of 300 to 600%.
Annealing at a temperature of 0.5 to 20.0 hours. (III) After annealing, cold working and further strain relief annealing are performed. The above steps (I) to (III) are performed in sequence. This is a method for manufacturing a high-strength, high-conductivity copper alloy.

Further, the second invention is the first invention, further including A in the alloy composition.
I%Be5Co, Fe, Hf, In.

M g SM n SP ,, S n s Z r s
One or more selected from the group consisting of Si in a total amount of 0. It contains 1 to 1.0 wt% of O, and the steps of hot working, cold working, and annealing are the same as in the first invention.

The reason why the alloy components in each invention are limited as described above is as follows.

Cr is added because it can be expected to cause precipitation hardening due to fine Cr grains, and also to obtain heat resistance associated with it.
The reason for setting the content of r to 0.05 to 1.0% by weight is that C
If the content is less than 0.05% by weight, the above-mentioned effects cannot be expected, and if it exceeds 1.0% by weight, the processability and conductivity will be significantly reduced, and the solderability will also be reduced. It is.

Ti is added because it forms an intermetallic compound with Ni in the base material through aging treatment, improving strength, heat resistance, and electrical conductivity.
By forming an intermetallic compound of i, a remarkable improvement can be seen compared to the addition of Ti alone. Ti content is 0.02v
If it is less than t%, the above effect cannot be expected; on the other hand, if it is less than 0.6wt.
%, undissolved Ti remains in the base material even after solution treatment, similar to Cr, resulting in significant deterioration of workability and conductivity.

Ni is added because it can improve strength and conductivity by forming an intermetallic compound with Ti.If the amount added is less than 0.05 wt%, the above effects cannot be expected; This is because if it exceeds 5vt%, the conductivity will deteriorate. Preferably the ratio of T i /N i is 0.2
It is recommended to set it to about 5 to 0.55.

Zn is added because it can be expected to significantly improve solder heat resistance and peelability without significantly reducing conductivity, and the amount of Zn added is 0. O1 to 3,0vt% is 0.01vt%
If it is less than 3, the above-mentioned effect cannot be expected, and conversely, if it is less than 3. This is because if it exceeds Dvt%, a significant decrease in conductivity occurs.

Furthermore, as a subcomponent, A1. , Be, CO% Fe s
Hf s I n s M g % M n SP
s S n sZr, one or more selected from the group consisting of Si in a total amount of 0. The reason for adding 1 to 1.0 wt% of O is that it can be expected to have the effect of improving strength without significantly reducing conductivity, and the total amount added is 0.01 wt%.
If it is less than vt%, the above-mentioned effect cannot be expected;
This is because if it exceeds this, significant deterioration of conductivity and workability will occur.

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

Step 1) After heating to a temperature of 850 to 1000"C for 0.5 to 5.0 hours, hot rolling is carried out. Immediately after hot rolling, the workpiece is rolled at a speed of l"c/sec. The reason for cooling it at
If the temperature exceeds 00°C, a liquid phase may appear in some parts. or,
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 that, there will be a significant decrease in strength and conductivity.

In step (U), after cooling, the workpiece is subjected to cold working of 50% or more, and the processed material is heated to a temperature of 300 to 0.5 to 20.
The reason for annealing for 0 hours is that it can be expected to improve strength and conductivity.If the cold working is less than 50% after cooling, no improvement in strength can be expected due to annealing, and if the temperature is 300
℃ or less than 0.5 hours, no improvement in conductivity can be expected, and even if the temperature exceeds 500℃ or the time is less than 0.5 hours,
This is because even if the time exceeds 0 hours, no improvement in strength can be expected. The most preferable heat treatment conditions are 350~4
1.0 to 3.0 hours at a temperature of 50°C.

The reason why cold working is performed after annealing in step (III) is that 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 a test material was produced under the manufacturing conditions shown in Table 1. For these test materials, the tensile strength, elongation, and electrical conductivity were measured, and a 90° repeated bending test was conducted.
The number of times of bending until breakage was determined as n1, with one round trip. Solderability was evaluated by vertical dipping method by immersing the product in a solder bath (60% Sn, 40% Pb) at 230±5° C. for 5 seconds and visually observing the wetting state of the solder. or,
Evaluation of solder heat resistance and peelability was performed by applying 5 μm solder plating to the material (
60% tin, 40% lead) and placed in a constant temperature bath at 150℃ for 20 minutes.
Hold until 00 hours, take out every 100 hours and hold at 90°
The sample was bent back and forth once, and the presence or absence of solder peeling was examined. These results are shown in Table 1 along with comparative alloys.

Book 1): Sample parallel to the rolling direction H) i: Sample perpendicular to the rolling direction Book 3) Good 2 Wet area after soldering 95% or more Poor, Wet area after soldering less than 95% Examples of the present invention and comparative examples An explanation is added below.

Inventive examples Nos. 1 to 5 are alloys of the components of the present invention manufactured by the manufacturing method of the present invention, and all of them are excellent in strength and conductivity, and also have good other properties.

Comparative example No. 6 has a low Cr content, so No. 8
Because the content of Ti and N1 is low, the strength is inferior to the example of the present invention even though it was manufactured by the manufacturing method of the present invention.

Further, since the Zn content of No. and 1O is low, the solder heat resistance and peelability are poor. Furthermore, No. 7 has a high Cr content, so
No. 9 has a high content of Ti and Ni, so No. 1
No. 1 has a high Zn content, so even though it was manufactured using the manufacturing method of the present invention, its conductivity was lower than that of the alloy of the present invention, and No. 7 had poor soldering properties.

On the other hand, No. 12 to No. 21 are alloys of the components of the present invention, but N 0.12 has a low ingot heating temperature, so N
0.13 has a short ingot heating time, No. 14 has a low cooling rate after hot rolling, No. 15 has a small degree of work before annealing, and No. 16 has a low annealing temperature. Therefore, No. 17 has a high annealing temperature, so No. 18
No. 19 because the annealing time is short, No. 20 because no cold working is performed after annealing,
The strength is inferior to the example of the present invention. Furthermore, No. 14
, No. 16, No. 18 have low conductivity.

Further, since strain relief annealing was not performed on No. 21, the bendability was inferior to that of the examples of the present invention.

[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 this alloy is excellent as a material for electronic parts used in semiconductor devices.

Claims (2)

[Claims] (1) Cr0.05-1.0wt%, Ti0.02-0
．． 6wt%, Ni0.05-1.5wt% and Zn0.
In a method of hot working, cold working, and annealing an alloy containing 0.01 to 3.0 wt% and the remainder Cu and unavoidable impurities, (I) 0.5 to 5.0 wt% at a temperature of 850 to 1000 °C;
After heating for an hour, hot rolling is carried out, and immediately after 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 manufacturing a high-strength, high-conductivity copper alloy for electronic devices, characterized by: (2) Cr0.05-1.0wt%, Ti0.02-0
．． 6wt%, Ni0.05-1.5wt%, Zn0.0
1 to 3.0 wt% and Al, Be, Co, Fe, Hf,
One or more selected from the group consisting of In, Mg, Mn, P, Sn, Zr, and Si in a total amount of 0.01 to 1.0 wt.
(I) 0.5 to 5.0% at a temperature of 850°C to 1000°C.
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 manufacturing a high-strength, high-conductivity copper alloy for electronic devices, characterized by: