Lead frame for fabricating surface mount type semiconductor devices with high reliability

A lead frame used for manufacturing semiconductor devices, said lead frame comprising:

• first and second half frame structure portions;
• and
• a plurality of bridge members for connecting said first and second half frame structure portions;
• wherein each of said first and second half frame structure portions comprises:
• first and second band shaped members disposed parallel to each other;
• a plurality of island portions for mounting semiconductor pellets thereon respectively, wherein said plurality of island portions are disposed at predetermined intervals between said first and second band shaped members, and wherein a first end portion of each of said island portions is connected to said first band shaped member;
• a coupling strip provided for each of said island portions, wherein said coupling strip is disposed between each of said island portions and said second band shaped member, wherein a first end portion of said coupling strip is connected to a second end portion of each of said island portions, and wherein a second end portion of said coupling strip is connected to said second band shaped member;
• and
• at least one electrode portion which is provided for each of said island portions and which is to be electrically coupled with a corresponding electrode of said semiconductor pellet mounted on each of said island portions, wherein said at least one electrode portion is disposed between each of said island portions and said second band shaped member, wherein a first end portion of said at least one electrode portion is connected to said second band shaped member, and wherein a second end portion of said at least one electrode portion is opposed to said second end portion of each of said island portions but is not connected to said second end portion of each of said island portions;
• and
• wherein said first and second half frame structure portions are disposed symmetrically such that said second band shaped members are located inside, and wherein said bridge members are connected to said second band shaped member of said first half frame structure portion and to said second band shaped member of said second half frame structure portion, thereby connecting said second band shaped members of said first and second half frame structure portions together.

A surface mount type semiconductor device comprising:

• a conductive island portion;
• a semiconductor pellet mounted on the top surface of said conductive island portion, said semiconductor pellet having at least one electrode formed on said semiconductor pellet;
• a conductive strip portion, one end of which connects to a portion of a first end portion of said conductive island portion;
• at least one electrode portion which is electrically coupled with corresponding one of said at least one electrode of said semiconductor pellet, each of said at least one electrode portion does not connect to said conductive island portion;
• and
• an encapsulation resin which covers and unifies said semiconductor pellet, said electrode portion, said conductive island portion and said conductive strip portion;
• wherein, at the bottom surface of said semiconductor device, the bottom surface of said conductive island portion and a portion of the bottom surface of each of said at least one electrode portion are exposed from said encapsulation resin;
• wherein said portion of the bottom surface of each of said at least one electrode portion exposed from said encapsulation resin and the bottom surface of said conductive island portion are coplanar with each other;
• wherein, at a side surface of said encapsulation resin, a first end portion of each of said at least one electrode portion and a second end portion of said conductive strip portion are exposed from said encapsulation resin;
• wherein the width of each of said at least one electrode portion is larger than the width of said conductive strip portion;
• and
• wherein a seond end portion of each of said at least one electrode portion is raised from said exposed surface of each of said at least one electrode and is located inside said encapsulation resin.