Multiscale Thermal Impact of BSPDN: SoC Hotspot Challenges and Partial Mitigation

Realistic workload-based CPU powermaps reveal that nonuniform dissipation majorly accentuates hotspots in BSPDN based designs. 1 $\mu m$ -resolution temperature simulations of an 80-core server SoC show ~ 14°C penalties relative to FSPDN caused by interplay of extraneous thermal resis-tance (BEOL + wafer bonding) and BSPDN heat spreading. Mitigation strategies are proposed and quantified.