Ball-grid-array integrated circuit package with solder-connected thermal conductor

A method of fabricating a packaged integrated circuit, comprising:

• inserting a thermally conductive slug into a substrate having first and second opposing surfaces, said thermally conductive slug having a first surface exposed at and protruding from the first surface of the substrate, and having a second surface opposite therefrom, wherein the second surface of said thermally conductive slug is coplanar with the second surface of the substrate;
• mounting an integrated circuit chip to the second surface of the thermally conductive slug;
• encapsulating said integrated circuit chip;
• attaching a first plurality of solder balls to the substrate at its first surface;
• and attaching a second plurality of solder balls to the slug at its first surface, wherein each of the second plurality of solder balls have substantially the same volume as each of the first plurality of solder balls.

An electronic system, comprising:

• a printed circuit board, having electrical conductors and a thermal conductor;
• and
• a packaged integrated circuit, comprising:
• a substrate having first and second surfaces, having an opening disposed therethrough, and having a plurality of electrical conductors;
• a slug, comprised of a thermally conductive material and having first and second surfaces, said slug having a portion extending through the opening of said substrate so that its first surface is exposed at said first surface of said substrate and extends below the first surface of the substrate, wherein its second surface is coplanar with the second surface of the substrate;
• an integrated circuit chip, mounted to the second surface of said slug, and electrically connected to the conductors of said substrate;
• a first plurality of solder leads disposed at the first surface of said substrate, and in electrical connection with the electrical conductors of said substrate and with electrical conductors of said circuit board;
• and
• a second plurality of solder leads disposed at the first surface of said slug, for making thermal connection to the thermal conductor of said circuit board.