Abstract: A novel multi chip module having a high accuracy of stacking and self alignment of integrated circuits (ICs) during the stacking process is provided by utilizing partially half etched lead frames and package guide lead frames. Heat dissipation is increased by a plurality of etched lead portions directly connected to the “Bottom IC” body and adhered to the “Top IC” body with thermally conductive glue. Applying the partially etched lead frame of this invention decreases number of steps in the IC stacking process. The lead frame used in this invention is made of the same material used in a genuine IC, providing optimal signal quality by minimizing any signal reflection.

Abstract: A novel multi chip module having increased accuracy of the soldering the integrated circuits (ICs) is provided by utilizing two additional lead frames and turning over the first lead frame soldered IC and stacking secondary IC thereon. Arrays of the first lead frames are mounted on a top tray guided by tooling pins. Solder pastes are printed on the first lead frames. Arrays of the second lead frames are placed on the first lead frames guided with tooling pins. Another layer of solder pastes are printed on the second lead frames. Thermal conductive glue is dispensed on the central portions of the first lead frames. ICs, which become the “bottom ICs” later, are placed on the central portions of the first lead frames upside down by a pick/place machine. After heat treatment, inspection and repair, the bottom ICs are mounted in a pocket on a bottom tray facing the first lead frames upside. Another layer of solder pastes are printed on the first lead frames.