Abstract: A low cost electronic device package having greatly improved heat dissipation capability. The package includes a heat slug, preferably formed from oxygen-free high-conductivity copper, that has a surface exposed outside the package. A simplified and inexpensive manufacturing method is described using a "drop in" technique. Using this technique, the size and shape of the heat slug is dependent only on the size and shape of the mold cavity; the package may have any number of leads and any size die. The heat slug is preferably formed with fins around its circumference so that the slug is self-aligning when it is dropped into the mold cavity. Preferably, slots are formed through the heat slug to provide improved encapsulant flow during the encapsulation process and interlocking between slug and encapsulant in the finished package.