JPH0526859B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a copper alloy used for ICs, LSIs, wire electrodes, etc., and particularly to a method for producing a copper alloy having high tensile strength. [Prior Art] In recent years, semiconductor technology has made remarkable progress, and in the very near future, 256K memory VLSIs will be manufactured in large quantities. Kovar was first used as an alloy for ICs, LSIs, etc., followed by 42 alloy, 52 alloy, etc. With the development of ultra-integrated circuits such as LSIs, alloys with particularly excellent electrical conductivity, thermal conductivity, and strength were required, and today iron alloys and copper alloys are almost the same. used in proportions. The relationship between electrical conductivity, which is the main element of this type of alloy, and strength is such that, in general, increasing electrical conductivity causes a decrease in strength. The subject of research is how to keep it low. Various methods have been studied to maintain high electrical conductivity and strength, among which a combination treatment with spinodal decomposition and other mechanisms is considered to be the best method. For example, Cu-Ni alloys were conventionally considered to be completely solid solution alloys, but spinodal decomposition occurs when special elements are added or when treatments are performed. In general, copper alloys have the property that the Young's modulus decreases when other elements are added, but Cu-Ni
In a spinodal alloy, by adding the above elements, the Young's modulus can be improved and the decrease in electrical conductivity can be suppressed to a low level. Therefore, when a Cu-Ni alloy is subjected to a combination of spinodal decomposition treatment and strengthening mechanism, for example, the strength
60Kg/mm ² and electrical conductivity of 80%, which is an extremely excellent value for an alloy for LSI at the time of its inception, and is also a value suitable for an alloy for VLSI. Furthermore, a requirement for this type of alloy is that it has a low coefficient of thermal expansion. In general, iron-based alloys have a small coefficient of thermal expansion, while copper-based alloys have a large coefficient of expansion. However, copper-based alloys are used as lead frame alloys because their thermal conductivity is approximately 10 times higher than that of iron-based alloys. Therefore, the biggest challenge in the future is how to lower the coefficient of thermal expansion of copper-based alloys. [Problems to be solved by the present invention] The present invention has been made based on the above-mentioned viewpoints, and its purpose is to have high tensile strength, as well as high electrical conductivity, thermal conductivity, and strength. The purpose of the present invention is to provide a high-strength copper alloy that can be used not only for LSI but also for VLSI and wire electrode materials. [Means for solving the problem] Therefore, the above purpose is to contain 0.3 to 8% Cr, 0.05 to 1% rare earth elements, and the balance unavoidable impurities and Cu. This is achieved by solution-treating a copper alloy consisting of in a magnetic field. [Function] If the copper alloy is manufactured in the manner described above, extremely high tensile strength can be obtained compared to conventional copper alloys, and the electrical conductivity and thermal conductivity can also be maintained high, so it can be used not only for LSI but also for VLSI. It can be used as a copper alloy for industrial use, and is also optimal as a wire electrode material, and can be used in a wide range of fields. The method for producing the high tensile strength copper alloy according to the present invention includes 0.3 to 8% Cr by weight percentage (the same applies hereinafter),
0.05 to 1% of at least one rare earth element selected from Y, Sm, Pr, Mitsushimemol, etc., and the balance being Cu, the above raw materials are melted at high frequency in the atmosphere and then cast into a mold to form an ingot. . When this ingot is solution-treated in a furnace at about 450°C to 650°C for 35 to 45 hours, the temperature in the furnace is maintained at 500°C to 600°C for 6 to 8 hours during the solution treatment, and A magnetic flux of 1000 Oe to 3000 Oe is applied for 6 to 8 hours, followed by hot or cold rolling. [Example] (1) Lead frame alloy rolled without applying a magnetic field Cr: 0.1 to 1% Y: 0.05 to 0.3% Remaining: Cu Ingots made by casting the above raw materials into a mold after high frequency melting in the atmosphere The above ingot was heated to 550℃.
Solution treatment was carried out in a furnace for 35 hours. (2) Lead frame alloy according to the present invention Cr: 0.1-1% Y: 0.05-0.3% Balance: Cu The above raw materials are melted at high frequency in the atmosphere and then cast into a mold to form an ingot.
When performing solution treatment for 35 hours in a furnace, a magnetic field of 1500 Oe was applied to the center of the furnace for 6 hours during the solution treatment, and the solution treatment temperature was maintained at 500°C.

〔Effect of the invention〕

Since the present invention is constructed as described above, the present invention can maintain high electrical conductivity, thermal conductivity, strength, etc., and therefore can be used as an alloy for lead frames of not only LSI but also VLSI. Moreover, it can also exhibit extremely excellent effects as a wire electrode.

Claims (1)

[Claims] 1. Cr of 0.3 to 8% by weight percentage (the same applies hereinafter);
1. A method for producing a high-strength copper alloy, which comprises solution-treating a copper alloy consisting of 0.05 to 1% rare earth elements and the remainder being unavoidable impurities and Cu in a magnetic field. 2 The magnetic field applied during the above solution treatment is 1000 Oe ~
3000 Oe. A method for producing a high tensile strength copper alloy according to claim 1. 3. The method for producing a high tensile strength copper alloy according to claim 1 or 2, wherein the rare earth element is Y. 4. The method for producing a high tensile strength copper alloy according to claim 1 or 2, wherein the rare earth element is Sm. 5. The method for producing a high tensile strength copper alloy according to claim 1 or 2, wherein the rare earth element is Pr. 6. The method for producing a high tensile strength copper alloy according to claim 1 or 2, wherein the rare earth element is Mitsushi metal.