What flow is followed for ECO / timing closure?

o   After post route database has acceptable timing and drc numbers, we start ECO phase.

o   If power recovery is reuired, start with power recovery where tool downsize or VT swap cells in timing paths with positive slack to save power.

o   Then start fixing drv/setup/hold timing. Generate ECO file manually or from STA tool, on single session or DMSA environment. Apply ECO on post route database in PNR tool, save design and dump outputs and rerun timing, Physical verification like DRC, LVS, Antenna, etc. IR EM analysis can be done.

o   Iterate ECO cycles till timing is clean. Once all ECOs are implemented and locally verified, run full signoff checks (STA, DRC, LVS, EM/IR) on the final ECOed database.

o   ECO Flow: https://teamvlsi.com/2021/02/eco-flow-in-physical-design.html