| 摘要 |
PURPOSE:To reduce the rate of wire breakdown and improve corrosion resistance by processing a high purity Al stock material into one having a specific diameter by processing the same by a hydrostatic wire drawing process such that an area ratio per a single processing is more than a specific value. CONSTITUTION:A 99.99% or more high purity Al stock material is processed by a hydrostatic wire drawing process such that an area ratio per single processing is 1.5 or more, to provide a bonding wire having several tens of mum. In the hydrostatic drawing wire process, pressure P is exerted on a wire material 1 through a pressure medium 3 to force out the wire material 1 from a die 3 for expansion and contraction of the same. With high purity Al, satisfactory corrosion resistance is assured. With application of a hydrostatic drawing wire process, wire breakdown is avoided together with the improvement of corrosion resistance. Further, with an area ratio per one time processing being made 1.5 or more, pressure processing is allowed to microcrystalize. |
