Chip-last embedded actives and passives in thin organic package for 1–110 GHz multi-band applications

This paper presents for the first time a novel manufacturing-compatible organic substrate and interconnect technology using ultra-thin chip-last embedded active and passive components for digital, analog, MEMS, RF, microwave and millimeter wave applications. The architecture of the platform consists of a low-CTE thin core and minimum number of thin build up organic dielectric and conductive layers. This organic substrate is based on a new generation of low-loss and thermally-stable thermosetting polymers (RXP-1 and RXP-4). Unlike LCP- and Teflon-based materials, the RXP material system is fully compatible with conventional FR-4 manufacturing processes. Ultra-thin silicon test die (55µm thick) has been embedded in a 60µm deep cavity with a 6-metal layer RXP substrate and a total thickness of 0.22mm. The embedded IC is interconnected to the substrate by ultra-fine pitch Cu-to-Cu bonding with polymer adhesives. This novel interconnection process performed at 180°C, has passed 1,000 thermal shock cycles in reliability testing. Because of manufacturing process simplicity and unparalleled set of benefits, the chip-last technology described in this paper provides the benefits of chip-first without its disadvantages and thus enables highly miniaturized, multi-band, high performance 3D modules by stacking embedded 3D ICs or packages with embedded actives, passives and MEMS devices.