| 摘要 |
PURPOSE:To improve electrical reliability by a method wherein invasion-stopping members designed to reject corrosive ions are provided at prescribed locations on inner leads and function to prevent such ions from arriving at the inside of a device. CONSTITUTION:Invasion-stopping members 4, provided at prescribed locations on inner leads 3A, tab-supporting leads 2A, absorbs corrosive ions penetrating in through gaps if any produced between the leads and sealing resin. Corrosive ions detrimental to the electrodes of a semiconductor chip are represented by OH<->, SO<->4, Cl<-> and NO<->3. An invasion-stopping members 4 is built, for example, of an aluminum film formed by means of evaporation or clad tape. The chemical reaction here hollows a formula: Al<+++>+2(OH)<->+Cl<-> Al(OH)2Cl. There is an increase in volume when Al develops into Al(OH)2 Cl by collecting corrosive ions. Such expansion in volume further improves the invasion-stopping feature by clogging a gap if any to ensure the stoppage of invading corrosive ions. |
