Thermal Insights of 3-D BS-PDN in Cloud Server SoC Using TCAD Modeling

Abstract

In this brief, the thermal performance of a large-scale cloud server system-on-chip (SoC) with the backside power delivery network (BS-PDN) and 3-D integration in memory-on-logic (MoL)/logic-on-memory (LoM) configuration with 2.5-D packaging is analyzed in advanced A10 nanosheet technology node using Sentaurus TCAD platform. The results show a 45.6% (~20.3 K) thermal penalty for the 80-core SoC in MoL with BS-PDN compared with the 2-D-baseline frontside PDN (FS-PDN), using a heatsink with forced cooling. A nonuniform power map further aggravates thermal concerns, which can be mitigated using an LoM configuration with BS-PDN, reducing the penalty to 22% (~15 K). Extending the study to a 320-core SoC, in conjunction with an advanced cooling system, LoM with BS-PDN shows 45.3% (~29 K) lower temperature than conventional MoL BS-PDN. The modeling results provide valuable insights and motivate future research into packaging and cooling techniques for BS-PDN integration.