| 摘要 |
PURPOSE:To prevent eccentricity of ball for stabilizing contact bonding to a substrate by performing pressure welding of a core material consisting of Ag or Ag alloy and a coated material consisting of Au or Au alloy, performing thermal diffusion treatments once or two times, or more, and then performing wire drawing to a particular diameter by cold working. CONSTITUTION:An Ag cylindrical bar 1 which is a core material is engaged to an Au pipe 2 which becomes a coated material to form a two-layer cylinder 3 and metals (dummy blocks) 7 and 8 for protection are coated around this periphery to form a compound coated material 10 (billet). After performing wire drawing of this into a compound coated wire using the hot static water pressure extrusion or hot lubrication extrusion, a coated wire is formed by removing a metal for protection and thermal diffusion treatment is performed for two times or more at a diameter which is two times or more of the target wire diameter during wire drawing machining. Furthermore, wire drawing is performed for a compound bonding wire with a wire diameter of 25-30mum. It allows eccentricity of ball to be restricted on bonding and the thickness of coated materials to be constant. |
