3D Capacitive Interconnections for High Speed Interchip Communication

A 3D interconnection scheme based on capacitive coupling for high speed chip to chip communication has been implemented in a 0.13 mum CMOS process. This paper provides detailed design example for both synchronous and asynchronous transmitter and receiver circuits. The first approach shows with electrodes 15 times 15 mum² a wide range of operating frequency up to 900 MHz with an energy consumption of 41fJ/bit. In the asynchronous scheme we demonstrate with electrodes 8 times 8 mum² a vertical propagation of clock at 1.7 GHz and a propagation delay of 420 ps for general purpose signal with energy consumption of 80 f J/bit. Functionality and performance have been demonstrated by using both die-level and wafer-level assembly flows and BER measurements show the reliability of these AC interconnections with no error on more than 10¹³ bits transmitted.