BS-PDN Implemented the Latest Logic Devices for 14 Angstrom Technology Node

This study extensively examines the relative cost-competitiveness between front-side (FS) and back-side (BS) power delivery networks (PDNs), ranging from the latest 200 nm height of the standard cell (STC) to the 14-angstrom node (A14). FS and BS-PDN necessitate a higher area increase rate for smaller technology nodes to meet the IR drop criterion. In the 3-nm node (N3) and below, power via (PV) requires a high area increase rate, posing challenges in competing with FS-PDN, especially for high-density (HD) cells. Depending on process conditions, the buried power rail (BPR) and BS contact (BSC) may also require additional area, although ideally, they do not. Consequently, BS-PDN becomes competitive through scaling. Nonetheless, in mobile system-on-chip (SOC), the added process cost of BS-PDN must be small to be a cost-effective alternative compared to FS-PDN even at A14. This study guides the return on investment (ROI) when adopting BS-PDN options.