Engineering Change Orders
Late fixes without full redesign.
Overview
ECOs fix functional or timing issues late in the flow without restarting the entire design. They are common in modern tapeouts.
Metal-only ECOs are faster and cheaper because they change only interconnect layers.
Typical ECO Triggers
Functional bugs discovered after signoff.
Timing violations caused by routing or late constraints.
Power or signal integrity issues that need targeted fixes.
Best Practices
Sprinkle spare cells throughout the layout.
Keep ECO changes localized to reduce risk.
Re-run critical signoff checks after ECO insertion.