Abstract: Packaged surface mount (SMT) chips having matched top contacts and bottom contacts are stacked. Chip features are selected to provide the desired connectivity between chip layers with a greater ease of manufacture. In one embodiment, additional spacing and routing layers are optionally provided between layers. In another, chips are differentiated by optionally providing different conductor and/or nonvolatile cell configurations. In yet another, a minority of a substrate's contacts are configured for aligning with a dielectric region of a spacing layer or substrate to create very low capacitance signal paths between stacked chips.