| 摘要 |
PURPOSE:To improve adhesion strength between inner leads and sealing resin and avoid slippage at the adhering part between them by providing a rough surface on the surface of a lead frame which is in contact with the sealing resin. CONSTITUTION:After a lead frame pattern is formed by a stamping process or an etching process, a rough surface 10 is formed by adding a chemical etching process which makes the surface matted. Then tip parts of inner leads 3b and a chip pad 2 are plated with gold or the like. The chemical etching which forms the rough surface 10 is corrosion etching which employs solution of nitric acid and phosphoric acid or solution of nitric acid and sulfuric acid as etchant for iron system metal stripe 1 material and employs solution of chromic acid and sulfuric acid as etchant for copper system metal stripe 1 material and the depth of the etching is about 1-3mum. With this constitution, sealing resin and the unevenness of the rough surface 10 gear with each other so that adhesion strength between the inner leads 3b and the sealing resin can be improved and peeling-off caused by the slippage between them can be avoided. |
