Overview of Clock Net Shielding Methodologies

There are 2 clock net shielding flow, the difference is clock net shielding is either before signal routing or post. You can use the following two shielding methodologies:

1. Shield before signal route: routing clocks + shielding clock nets + routing signal nets
2. Shield after signal route: routing clocks + routing signal nets + shielding clock nets

The flow charts below describe each of the methodologies:

Shielding clock nets before routing signal nets yields better shielding coverage. However, this methodology can cause more DRC violations during signal net routing.