PURPOSE: To obtain a semiconductor device wherein a solder fillet is surely formed at the tip face of a lead.

CONSTITUTION: A lead frame provided with an outer lead 5A where a groove is previously provided to the upside of its tip is used or a process wherein a groove is provided to the upside of the tip of a outer lead frame 5B is provided before a solder plating process is carried out, whereby a solder-plated layer 7 is provided to the upside of the tip of the outer lead of a semiconductor device Sa. By this setup, the solder plated layer 7 formed on the tip of the outer lead and solder paste 10 on a wiring printed board 9 are attracted to each other to form a solder fillet 11 at the tip face of the lead, so that, a soldered joint between the lead and the board 9 can be easily ascertained and enhanced in bonding strength.