A system in a package (SIP) or multi-chip module (200, 300, 400) (MCM) uses an electron beam (235, 335, 435) for electrically coupling between microcircuits (230, 330, 430) and (232, 332, 432). In one embodiment, the micro-circuits (230, 430) and (232, 432) can be configured in a side-by-side configuration. In another embodiment, the micro-circuits (330) and (332) can be configured in a chip-on-chip configuration. In yet another embodiment, the electron beam (435) can include a plurality of electron beams (436) and appear as ribbon shaped between two micro-circuits (430, 432). Further, the fabrication to form the electron source (234, 334, 434) and the deflector (261, 356, 461) can be at the final metallization step of the process.