Functional ECO automation challenges and solutions

Late Register Transfer language (RTL) changes also called as Engineering Change Orders (ECOs) pose a big challenge to the design community. This is due to the reason that the ECO changes are to be made directly in the final converged netlist which differs significantly with the RTL due to optimization and convergence. Since the ECOs are done very close to tape out, these are time critical missions and any inefficiency in implementation will directly impact the cost of the product. This is the motivation behind the automation solutions that exist today for solving the functional ECO problem. A successful ECO is not only measured based on the functional equivalence with the new RTL but also on the quality of the ECO changes made. If the ECO tool inserts a lot of new logic in the converged netlist resulting in routing congestion and timing issues, it may not be possible to implement the ECO though the final netlist passes Functional Verification (FV). Thus there are a few criteria to successfully implement a functional ECO. This paper discusses the ECO challenges and reviews the criteria for a successful functional ECO solution. It also consolidates the ideas that will help to solve the issues that happen during a functional ECO.