JPS6376774A - Heat resistant high electrical conductivity copper alloy clad material - Google Patents

Abstract

PURPOSE:To contrive reduction of a production cost, etc., by forming a core material of a dispersion strengthened copper formed by subjecting a copper alloy contg. specific weight % of Al and consisting of the balance copper to an internal oxidation treatment and constituting the sheath of a copper alloy contg. prescribed % of Zr, etc. CONSTITUTION:The copper alloy material contg., by weight, 0.15-1% Al, and consisting of the balance copper is prepd. and is formed to powder or foil by a pulverizing method or rolling of ingots. The powder or foil is then subjected to the internal oxidation treatment for the Al in the copper alloy by heating, etc., in an inert gas to disperse alumina particles into the copper matrix of the copper alloy powder or foil, by which the dispersion strengthened copper material is formed. Said mold is worked to the core material. The sheath made of the copper alloy contg. 0.03-0.40% Zr or 0.03-0.10% Zr and 0.3-1.5% Cr is formed on the surface of the core material by a hot extrusion method, etc. The production cost is reduced by the decreased treating stages and working man-hours and the quality of the product is improved as well.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a heat-resistant and highly conductive copper alloy cladding material, which can particularly effectively reduce manufacturing costs, and which can be used for lead materials for semiconductor devices and electrode materials for spot welding. The present invention relates to a heat-resistant and highly conductive copper alloy clad material that can be suitably used as a heat-resistant and highly conductive copper alloy cladding material.

(Prior art and its problems) Generally, lead wires and lead frames for semiconductor devices include
In addition to having high electrical conductivity, it has the strength necessary for manufacturing and installation, and its strength does not deteriorate even through thermal treatments such as brazing and glass sealing performed during the manufacturing process. In addition, parts are required to have excellent heat resistance strength, but iron-based materials such as 5ONi-Fe, pure copper, copper alloys, etc., which have been conventionally used as materials for lead wires and lead frames, are required. In copper-based materials, increasing the heat resistance tends to lower the electrical conductivity, so it has been extremely difficult to obtain materials with satisfactory properties.

Similarly, materials for spot welding are required to have high electrical conductivity and excellent heat resistance.
Conventionally used Cu-Cr, Cu-Ti-Cr
Age-hardenable copper alloy materials such as the above have low aging temperatures and do not have sufficient heat resistance strength.

Therefore, in order to deal with such problems, a copper alloy clad material with excellent conductivity and heat resistance strength, whose core material is made of alumina dispersion-strengthened copper and whose outer material is made of pure copper or copper alloy, is used for semiconductor devices such as those mentioned above. It has been proposed to be used as a lead material for industrial applications or as a material for spot welding.

By the way, the core material in such a copper alloy clad material is made by subjecting Cu-AN alloy powder to alumina dispersion strengthening treatment, and its manufacturing method is described, for example, in JP-A-59-31.
Various streamlined methods have been proposed in JP-A No. 838 and JP-A No. 59-153850, etc., but each method requires preparation of alloy powder, oxidation treatment, reduction treatment in the manufacturing process. , pulverization, etc., and the manufacturing process is complicated and troublesome. Compared to materials manufactured by the conventional 1M method, such alloy materials are There is an inherent problem in that the manufacturing cost is extremely high, and therefore, the current situation is that its practical use is only seen in a limited number of sectors.

However, with the miniaturization and higher performance of electrical equipment and the automation of assembly lines in recent years, there has been a growing demand for superior conductivity and heat resistance for lead materials for semiconductor devices and electrode materials for spot welding. Therefore, there is a strong desire to reduce the manufacturing cost of copper alloy crund materials with excellent performance as described above.

Therefore, the present inventors believe that reducing the amount of core material used, that is, the area ratio of the core material to the total cross-sectional area, will lead to lower manufacturing costs in such copper alloy clad materials. As a result of extensive research, we have obtained the following knowledge, and based on this we have completed the present invention.

In other words, the cross-sectional area ratio of the core material to the outer skin material in the copper alloy cladding material as described above is determined depending on the application and required characteristics, but in reality, the area ratio of the core material to the outer skin material ( It has been difficult to set the amount (amount used) based on the theoretical minimum value for such characteristics.

For example, lead wires for semiconductor packaging and PGA (Pin
For the pin material of Grid A1)ey), it is only necessary to obtain a predetermined heat resistance strength, so by increasing the amount of alumina in the core material, the ratio of the outer skin material, which has inferior strength, can be reduced to the current level. Theoretically, it is possible to increase the properties even higher than those of -1) 1Q, and even for spot welding electrode materials, the exposure to high temperatures in contact with the welded material during welding is -1) 1Q. , only the central part of the cross section with a diameter of about 6 to B1 mφ is required, and only this part is required to have heat resistance strength, and the remaining part only requires technical strength, so it is not required due to its characteristics. The cross-sectional area ratio of the core material is usually about 25%.

However, in such copper alloy clad materials, the deformation resistance at high temperatures between the core material, alumina dispersion-strengthened copper, and the outer skin material, taro copper or copper alloy, is significantly different, so the area ratio of the core material must be adjusted accordingly. If the theoretical minimum value for such properties is set, the core material will break during hot extrusion.Therefore, in order to obtain a good rudd material, the cross-sectional area of the core material must be It was necessary to increase the ratio, and the required minimum area ratio is about 40% when the amount of Ai is small, and increases to 60 to 70% as the amount of All increases.

(Solution Means) Here, the present invention has been made against the background of the above-mentioned circumstances, and is characterized by containing 0.15% to 1% of aluminum by weight, and the remainder being copper. A core material made of a dispersion-strengthened copper material in which alumina particles are finely dispersed in a copper matrix obtained by internal oxidation treatment of a copper alloy made of A heat-resistant and highly conductive copper alloy cladding material comprising an outer skin made of a copper alloy containing 0.03% to 0.40% of zirconium.

Also, in the present invention, 0.15% to 1% by weight
A core material made of a dispersion-strengthened copper material in which alumina particles are finely dispersed in a copper matrix, obtained by internal oxidation treatment of a copper alloy containing % aluminum and the balance copper; Covers the outer surface of, from 0.03% by weight
It also features a heat-resistant and highly conductive copper alloy cladding material composed of an outer skin made of a copper alloy containing 0.10% zirconium and 0.3% to 1.5% chromium. .

(Specific Structure) By the way, the dispersion-strengthened copper material constituting the core material in the cladding material according to the present invention is made by internally oxidizing a copper alloy containing 0.15 to 1% aluminum and the balance being copper. Then, it will be manufactured. Note that if the aluminum content in such a copper alloy is less than 0.15% by weight, little improvement in strength and heat resistance due to internal oxidation can be expected, and if it exceeds 1% by weight,
Processing into the intended clad material, especially hot extrusion processability, may be reduced.

Then, the copper alloy having such an aluminum content is made into a predetermined copper alloy powder according to a known powdering method such as a gas atomization method or a pulverization method, or a predetermined copper alloy powder is made according to a known metal foil manufacturing process by rolling the ingot. It will be made into copper alloy foil.

The copper alloy powder or copper alloy foil thus obtained is then subjected to internal oxidation treatment according to a conventional method. For example, alumina (Alzch) is first oxidized by heat treatment in an oxidizing atmosphere, generally in air, so that the aluminum component in the copper alloy powder or cylinder is oxidized.
Oxygen equivalent to the amount of oxygen that can be
After being made into powder or foil containing copper oxides such as 2O and CuO, the copper is generally heated to a higher temperature in an atmosphere consisting of an inert gas such as Ar gas. Selective internal oxidation treatment of the alloy powder or the aluminum in the cylinder will proceed. Of course, various other methods have been proposed for this internal oxidation treatment, and any of them can be adopted in the present invention. For example, instead of pre-oxidation treatment of copper alloy powder, Techniques such as oxidizing a portion or incorporating other copper oxides as an oxidizing agent are appropriately employed.

Such internally oxidized copper alloy powder or foil becomes the desired dispersion-strengthened copper material in which alumina molecules are dispersed in a copper matrix. is subjected to a reduction treatment consisting of heating to a temperature of about 500 to 950° C. in a reducing atmosphere, for example, a hydrogen atmosphere, in order to reduce copper oxides present therein, if necessary.

In addition, the dispersion-strengthened copper material (foil) obtained from the copper alloy foil as described above may be processed into a predetermined core material prior to or after the reduction treatment, or during the internal oxidation treatment process. Then, a cutting process is performed to form a predetermined small piece or thin piece. This cutting process is performed using an appropriate cutting device such as a slitter or a cutter, and the pieces are cut into strips with a width of about 5 to 50 fins, which are then used for processing the core material. It is.

The thus obtained dispersion-strengthened copper material in the form of a powder or cut foil is used as it is, or after being made into a compression molded body of a predetermined shape according to an ordinary method, it is processed into a Cu-Zr alloy or a Cu-Zr alloy having an appropriate shape. After being sealed in a container made of Cu-Cr-Zr alloy and deaerated, a predetermined hot processing such as hot extrusion is carried out to obtain the desired product form (molded body) under this condition. be done. Through this hot processing, the compression molded product becomes a processed material of a predetermined shape, such as a wire rod, bar material, or plate material, which has the material of the container that houses it as an outer skin. After the hot working, cold working, drawing, etc. are performed as necessary, and the desired cladding material is finished.

By the way, by processing the dispersion-strengthened copper material into a predetermined shape for each container containing it according to such hot processing, the obtained processed material is such that the dispersion-strengthened copper material serves as the core material. The clad material structure is formed by forming an outer skin made of the material of the container that covers the outer surface of the core material. In the present invention, the Cu-Zr alloy used as the container material that provides this outer skin is zirconium. A copper alloy containing 0.03 to 0.40% by weight of zirconium, and a Cu-Cr-Zr alloy containing 0.03% to 0.40% by weight of zirconium.
Contains 0.3 to 0.10% by weight and 0.3% chromium
Copper alloys containing in proportions of ~1.5% by weight will be used, respectively.

In other words, the Cu-Zr alloy having such a composition is a copper alloy with high deformation resistance at high temperatures, and its conductivity can be improved by heat treatment (brazing, glass sealing, welding, etc.) at 500 to 800°C. Rate is I AC3 value is 9
It can be recovered to 0% or more. In this copper alloy, if the Zr content is less than 0.03% by weight, a sufficient deformation resistance value cannot be obtained;
If the amount exceeds 5% by weight, the conductivity decreases, which is undesirable.

Moreover, even if the Cu-Cr-Zr alloy has the above-mentioned composition, it has a larger deformation resistance value than the Cu-Cr alloy, and its conductivity can be improved by heat treatment at 500 to 800°C. The rate can be restored to more than 80% with the lAC3 value.

In addition, in this copper alloy, the Zr content is 0°03
% by weight, or the Cr content is 0.3% by weight.
If the Zr content is less than 0.10 wt%, a sufficient deformation resistance value cannot be obtained, or if the Cr content is more than 1.5 wt%. In addition to not being able to obtain sufficient electrical conductivity, the density of giant primary crystals increases and the metal structure becomes non-uniform.
Undesirable.

Furthermore, all copper alloys with such compositions can be sintered by air cooling after hot extrusion, even without solution treatment and water cooling treatment in the manufacturing process of the cladding material. This means that the strength can be restored by heat treatment at about 500°C. The most preferable heat treatment temperature for these copper alloys is about 500°C, which allows the strength to be recovered extremely well.
Even in the above cases, it is possible to obtain greater strength than pure copper.

Therefore, by using the above-mentioned copper alloy as the outer skin material, the difference in deformation resistance between the outer skin material and the core material can be effectively reduced, thereby preventing the core material from breaking during hot extrusion. , reduce the ratio (amount used) of the core material,
It becomes possible to approach the theoretical minimum value of the desired properties of the cladding material, and thus it becomes possible to effectively reduce the manufacturing cost of the cladding material. As mentioned above, the excellent conductivity and heat-resistant strength of such a cladding material can be recovered by heat treatment, so by reducing the proportion of the core material made of dispersion-strengthened copper material, such a cladding material can be improved. There is no significant decrease in the electrical conductivity and heat resistance strength of the material.

By the way, in the clad material according to the present invention, the cross-sectional area ratio of the core material to the total cross-sectional area of the clad material is 50.
% or less is particularly preferable. However, in a cladding material formed with such a core material ratio, sufficient strength and conductivity can be exhibited with the above-mentioned Al content of the core material and composition of the outer skin material, which is a major objective of the present invention. Therefore, a reduction in manufacturing costs can be achieved more effectively. For this reason, when manufacturing such a cladding material, the copper alloy tube constituting the outer skin material should have a wall thickness such that its hollow internal area is 50% or less of the total cross-sectional area including the hollow part. The body will be used suitably.

(Effects of the Invention) Therefore, in the clad material according to the present invention, it is possible to reduce the usage ratio of the core material to the outer skin material while maintaining excellent conductivity and heat resistance strength. As a result, the amount of Cu-A1 alloy powder used can be reduced, and billet manufacturing steps such as atomized powder manufacturing, oxidation treatment, reduction treatment, and crushing operations can be effectively reduced. Cost reduction can be achieved extremely effectively.

In addition, such clad materials exhibit excellent electrical conductivity and heat-resistant strength even if no special heat treatment is applied to the outer skin material, through heat treatment such as brazing applied during use. It also has the following advantages.

Since the cladding material according to the present invention has been able to effectively reduce the manufacturing cost, it has been found that the cladding material has superior performance due to its high manufacturing cost. Cu-A whose practical application was postponed
A copper alloy cladding material having a core material made of a 1 z Oz dispersion strengthened alloy material can be supplied at low cost to various fields, and is particularly useful for lead wires and lead frames for semiconductor devices, electrodes for spot welding, etc. Therefore, the performance of the device or device that is the product can be effectively improved.

(Example) In order to clarify the present invention more specifically, Examples of the present invention will be given below, but the present invention is not limited in any way by the description of such Examples. It goes without saying that.

Furthermore, in addition to the following examples and the above-mentioned specific description, various changes may be made to the present invention based on the knowledge of those skilled in the art, as long as they do not depart from the spirit of the present invention. It should be understood that the invention can be implemented in any format.

First, copper alloy powder with a particle size of 297 μm or less was produced using the usual Ar gas atomization method using molten Cu-A1 alloys having various Al contents of 0.17 to 1.2% by weight. did.

Then, these copper alloy powders are subjected to oxidation treatment using either method A or method B described below depending on the amount of Al contained in each powder to obtain heat-resistant internal oxidation treatment. It was made into a reinforced powder.

Method A: Take out a predetermined amount of copper alloy (Cu-Aj) powder, pre-oxidize it, then mix the pre-oxide with the original copper alloy powder at a predetermined ratio, and This mixed powder is annealed at 950°C for 3 hours in Ar gas to convert A1 in the original alloy powder into AlzOi using preliminary oxides Cu and O. The mixing ratio of the copper alloy powder and preliminary oxide was based on data determined in advance so that when heated to a high temperature of about 950° C., Al would be converted to ultrafine Al, 02.

Method B [Alloy (Cu-Aj powder was heated at 350°C x 1
After oxidizing the surface at a low temperature of about 1 hour, annealing in Ar gas at 950°C for 3 hours oxidizes Al in the copper alloy powder to AAzOz with Cut 01CuO, and then annealing in an H2 stream at 800°C. By performing reduction treatment for 1 hour, remaining excess Cut 01C
Oxidation treatment method by reducing uO.

In other words, method A does not require the oxidation treatment compared to method B, so the oxidation treatment is easier, but as the amount of Al in the original copper alloy powder increases (as A large amount of CuO1CuO is required, and the amount of unreacted CuO1CuO remaining after annealing at high temperatures in Ar gas also increases.If the remaining amount exceeds the limit value, the amount of For example, the content of AAi may reduce cold drawing processability or cause drawing breakage.
is 0.4% by weight or more, method B is preferably adopted in which the entire amount of the copper alloy is oxidized in advance and then the excess oxide is removed by reduction treatment. In the example, depending on the amount of Al in each alloy powder,
Both methods are selected and adopted.

Thereafter, each of the obtained oxidized powders was made into a Cu powder with an outer diameter of -681 mm, a length of 150 mm, and a wall thickness of 8 to 15 m.
After filling a -Zr alloy tube or a Cu-Cr-Zr alloy tube and further heating it to 950°C, hot tube extrusion was performed through a die to obtain an extruded rod of 16 mmφ.

Note that this hot tube extrusion was performed using a tapered die at an elevation angle of 60 degrees and an extrusion speed of 1 to 2 m/min. The external appearance of the obtained extruded rods was observed, and the results are shown in Table 1 below. The appearance defects of the extruded rods were all due to cupping cracks in the core material.

Furthermore, by performing cold working using each extruded rod obtained in this way, 0,76*m
Finished as a φ wire rod. And 7 for those wires
After annealing at 50° C. for 30 minutes, the strength and conductivity of each wire were measured, and the results are also shown in Table 1. As for the strength, we will measure the stiffness value and the core hardness, and here, the stiffness value is determined using an ASTM test method test method No. 13 moment method testing machine, with a sample set length of 170n. The strength was evaluated based on the bending angle of the sample when a Log load was applied to the end. Further, the electrical conductivity is expressed as an IAC:S value, which is the electrical conductivity when pure copper is set to 100.

For comparison, oxygen-free copper (OFG) was used as the outer skin material.
Similar observations and measurements were made for the products using the above, and the results are also shown in Table 1 as conventional products.

As is clear from Table 1, the products of the present invention (numbers 1 to 4)
), the extrusion results are good, and the strength of the heat treatment (annealing) of the wire rod is 21 to 46 degrees, which is sufficient for practical use. Even in terms of ratio, the lAC3 value was 84% or more, and it was confirmed that the material had sufficient characteristics as a conductive material.

On the other hand, among the comparative products, problems 5 to 7 have A component in the outer skin material (copper alloy pipe), and Nos. 8 and 9 have A in the core material (copper alloy powder).
1 is outside the scope of the present invention, but as is clear from Table 1, wire rods other than 1lh8 cannot be subjected to cold working due to poor extrusion. The value was over 50 degrees, indicating insufficient strength.

In addition, with conventional products that use oxygen-free copper (OFC) as the outer skin material, IVkLIO lacks strength! 1)1)1)
These were defective in extrusion, and the properties of all of these were extremely inferior to those of the products of the present invention.

Claims (4)

[Claims] (1) Contains 0.15% to 1% aluminum by weight,
Obtained by internal oxidation treatment of a copper alloy, the remainder of which is copper,
A core material made of a dispersion-strengthened copper material in which alumina particles are finely dispersed in a copper matrix, and a copper alloy containing 0.03% to 0.40% zirconium by weight, which covers the outer surface of the core material. A heat-resistant, highly conductive copper alloy cladding material consisting of an outer skin and a heat-resistant, highly conductive copper alloy cladding material. (2) The copper alloy cladding material according to claim 1, wherein the core material is covered with the outer skin at a cross-sectional area ratio not exceeding 50%. (3) Contains 0.15% to 1% aluminum by weight;
Obtained by internal oxidation treatment of a copper alloy, the remainder of which is copper,
A core material made of a dispersion-strengthened copper material in which alumina particles are finely dispersed in a copper matrix, 0.03% to 0.10% by weight of zirconium, and 0.3% by weight of zirconium covering the outer surface of the core material. A heat-resistant and highly conductive copper alloy cladding material comprising an outer skin made of a copper alloy containing 1.5% to 1.5% of chromium. (4) The copper alloy clad material according to claim 3, wherein the core material is covered with the outer skin at a cross-sectional area ratio not exceeding 50%.