| 摘要 |
PURPOSE:To improve bonding properties, to enhance adhesive properties between a frame and a mold in molding sealing and to elevate the reliability of an IC by coating the whole surface with either of Ag, Pd or Ru or these alloy in specific thickness and particularly coating the nose section of an inner lead with it in 1mum or more. CONSTITUTION: The whole surface of a lead frame is coated with either of Ag, Pd or Ru or these alloy in 0.02-0.2mum, and the nose sections 2 of inner leads are coated with either of Ag, Pd or Ru in 1mum or more. The nose sections 2 of the inner leads are coated with Ag, Pd or Ru because these metals are difficult to be oxidized, and metallic small-gage wires 7, etc., are joined stably with high reliability. Since these metals or alloy is difficult to be oxidized, it is not oxidized by heating at the time of bonding, thus holding adhesive properties with molding to a high degree. The coating can reduce or omit the strong-acid treatment or activated flux treatment of outer lead sections 3 for pretinning in mounting to a printed substrate. |
