Wide-band simulations of differential 3D interconnect propagation performances in a photonic interposer

The continuous requirement of higher communication bandwidths in data centers or high performance computers drives the convergence between ASICs and optical I/Os. Combining 3D integration and Si-photonic technologies on a photonic interposer platform would offer tremendous opportunities for performance improvement assuming that 3D electrical paths are efficiently managed. Routing strategies for die-to-die and die-to-substrate interconnect paths in a photonic interposer are studied through RF modelling of 3D interconnect chains. Wide-band models, extracted from 3D electromagnetic simulations for each elementary 3D interconnect section are cascaded in order to compare the performances of interconnect networks used in the photonic interposer. Transmission losses up to 100 GHz are estimated in frequency domain for differential propagation modes. Next, eye-diagrams, delays and rising-times are observed with a 100 Gbps PAM-2 digital signal for several routing paths. Results led to the identification of critical interconnect sections and the establishment of design tools to optimize the routing paths in photonic interposer architectures.