Surface-mounting type semiconductor package having an improved efficiency for heat dissipation

A semiconductor device comprising:

• first and second semiconductor chips that are separate from each other;
• a first resin package body accommodating said first semiconductor chip, said first resin package body having a lower edge;
• a second resin package body accommodating said second semiconductor chip, said second resin package body having a lower edge;
• a first group of interconnection leads provided on said first package body and projecting outwardly from said first package body at said lower edge thereof, said first group of interconnection leads including a plurality of leads each having an inner lead part held inside the first package body and connected electrically to said first semiconductor chip, and an outer lead part located outside and said first resin package body for engagement with a substrate;
• a second group of interconnection leads provided on said second package body and projecting outwardly from said second package body at said lower edge thereof, said second group of interconnection leads including a plurality of leads each having an inner lead part held inside the second resin package body and connected electrically to said second semiconductor chip, and an outer lead part located outside the package body for engagement with said substrate;
• and
• a heat dissipation lead connecting said first resin package body and said second resin package body with each other, said heat dissipation lead comprising a first stage part embedded within said first resin package body and holding said first semiconductor chip thereon, a second stage part embedded within said second resin package body and holding said second semiconductor chip thereon, and a heat sink part located outside said first and second resin package bodies bridging said first stage part and said second stage part;
• each lead forming said first group of interconnection leads having said outer lead part at a level substantially flush with each said outer lead part of said second group of interconnection leads such that said semiconductor device is held upright on the substrate by said outer lead parts of said first and second group interconnection leads.