High-purity Cu bonding wire

Abstract

Provided is a ball bonding wire of a high-purity copper alloy, the wire having a high recrystallization temperature and being easily produced through wiredrawing with a die at room temperature. The ball bonding wire has a low initial ball hardness and causes no breakage of IC chips. Phosphorus (P) is added in an amount as slight as 0.5-15 mass ppm to high-purity copper having a purity of 99.9985 mass% or higher to thereby produce a copper alloy which has a higher recrystallization temperature than high-purity copper having a purity of 99.9999 mass% or higher and which has a lowered initial ball hardness in ball bonding. Those characteristics are thus achieved. Alternatively, phosphorus (P) is added in an amount as slight as 0.5-15 mass ppm to high-purity copper having a purity of 99.9985 mass% or higher, and the total amount of any other impurities contained in the copper is reduced to a value lower than the phosphorus (P) content. Those characteristics are thereby achieved.

Description

technical field [0001] The present invention relates to a copper alloy lead for connecting substrates such as IC chip electrodes and wires by a ball bonding method using a wire bonding machine, and more particularly to a bonding lead having a soft starting ball (FAB) room temperature hardness. Background technique [0002] Conventionally, as a method of connecting the electrodes of the IC chip and the wires on the substrate, a method of wiring by ball bonding using a high-purity copper alloy lead instead of the gold lead is known. [0003] In the method of wiring by the ball bonding method, the following method is generally adopted: the high-purity copper alloy lead wire protruding from the winding machine is introduced into the welding tube as the welding tool, and then, through the micro-discharge between the electrode welding gun, The tip of the copper alloy lead introduced to the exit side of the tool is melted in an inert atmosphere or a reducing atmosphere to form a st...

AI Technical Summary

Problems solved by technology

However, when there is oxygen in the ball bonding atmosphere, even the high-purity copper alloy lead, the initial solder ball (FAB) will not form a spherical shape, or the initial solder ball (FAB) will become too hard, causing the IC chip of the semiconductor to crack The problem

For this reason, it is impossible to perform high-strength, satisfactory thermocompression bonding using the initial ball (FAB), or to draw a satisfactory circuit. So far, the use of high-purity copper alloy leads has not been able to achieve the experience. practical level

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