| 摘要 |
<p>PURPOSE:To improve reliability of soldering by emplying a material having an intermediate layer of metal exhibiting excellent wettability with a solder on a lead frame to be used, and furthe cutting a part of an outer lead, to become its end from a mounting surface. CONSTITUTION:A 42 alloy (Ni 42%-Fe 52%) formed as a silver film of several mum is, for example, employed as an intermediate layer 18 of a lead frame. A normally used solder plating is executed about 10mum as a sheath solder plating on an outer lead 12. However, since an end 14 of the outer lead is mechanically cut from a mounting surface side, a sheath solder plating 13 film is sagged to be adhered from the mounting surface of the cut surface to the layer 18. The solder wetted state of the end 14 of the lead when a semiconductor device 11 of this state is mounted by soldering, is effectively solderwetted from the layer 18 of the cut surface of the end 14 of the lead to the mounting surface. Thus, reliability of the soldering is improved.</p> |
