Considerations for Transmission Line Design on MCMs using AC Coupled Interconnect with Buried Solder Bumps

AC coupled interconnect (ACCI) using buried solder bumps is a technology that provides a complete interconnect and packaging solution by integrating high-density, low inductance power and ground distribution with high-density, high-speed I/O. The mixture of solder bump technology and AC coupled I/O has the potential to improve yield during packaging and assembly since I/O channels are no longer dependent on the yield of a single solder bump. For the same reason, this technology has the potential to increase the long-term reliability of chip/carrier components of electronic systems used in harsh environments (e.g. extreme vibration, shock, and temperature variation). An important consideration in systems using this technology is how the electrical properties of transmission line are altered when it is routed beneath a die that is in close proximity (< 5 mum) to the surface of the substrate