Abstract: A chip carrier with improved packing density, wherein at least one layer of chips is bonded not directly to the substrate, but rather to a heat plate which attaches over the chip cavity and inside the hermetic sealing lid. The heat plate has openings in it to permit attachment of the leads from the chips in the upper layer to bond pads on a bonding ledge inside the cavity of the chip carrier, after the heat plate is emplaced. Each bonding ledge is preferably made somwhat wider than it would otherwise be, and the leads from multiple layers of chips are preferably bonded onto the same bonding ledge.