BONDDRAHT.

摘要

The present invention relates to bonding wires for connecting semiconductor elements used in transistors, ICs, LSIs and the like to external leads. The bonding wires are made of copper having a purity equal to or more than 99.99% by weight in which the content of any element selected from a first impurity element group consisting of silver and silicon is 5 ppm or less; the content of any element selected from a second impurity element group consisting of bismuth, iron, nickel, tin, sulfur, phosphorus and lead is 1 ppm or less; the content of a third impurity or oxygen is 5 ppm or less; and the sum total of all the contents of elements selected from the first, second and third impurity element groups is 10 ppm or less. The bonding wires form copper balls having hardness similar to that of gold balls of conventional gold fine wires, thus preventing silicon semiconductor elements from being damaged when connected.