An expansion module for mounting in an expansion slot of a computer includes a board with a plurality of apertures formed therein. Each aperture has a first chip package disposed substantially therein and a second chip package mounted to the board in a substantially spaced relationship to the first chip...http://www.google.de/patents/US6094355?utm_source=gb-gplus-sharePatent US6094355 - High-density computer modules with double-layer packaging
