IBM ES/9000 buried engineering change modeling for verification (MCM)

Buried engineering change (BEC) is a method of laying out engineering change (EC) wires within a multichip module (MCM) at the original building time for later use. The authors discuss the modeling used to accurately predict delay, validate electrical integrity, and add a degree of flexibility to the wiring process. The purpose of developing this BEC modeling methodology was to provide fast, accurate electrical verification and timing without using slower circuit modeling tools on individual nets. By modeling classes of nets an equivalent model concept was developed that provided fast timing and verification of all nets. This modeling methodology centers around maintaining the original modeling structure for a net that is physically different when engineering-changed. The IBM ES/9000 timing and verification tools accurately predicted net timing for BEC nets.<>