| 摘要 |
PURPOSE:To enhance adherence to resin and to improve reliability by a method wherein an Fe-Ni alloy is used, composed of Fe, a certain weight percentage of Ni, and inevitable impurities, with its superficial roughness set at a specific value. CONSTITUTION:Any Fe-Ni alloy usable as a sealing agent in an ordinary lead frame serves the purpose and, generally, an Fe alloy containing 30-55% of Ni is used. An alloy containing less than 30% or more than 55% of Ni has an extremely high thermal expansion factor and therefore is not good as a material for an ordinary lead frame because such a high thermal expansion factor renders poor its affinity with a semiconductor element. An Fe-Ni strip has a high adherence to resin when its surface is rough enough and therefore a superficial roughness of 0.4mu or less cannot attain a satisfactory result. A roughness exceeding 40mum may realize a higher adhesion but, due to excessive deformation of leads in a lead frame punching process, difficulties will arise in the wire-bonding process. The superficial roughness is therefore set at 0.4-40mu. |
