Shielding Drop at Post-Route

• There is a gap between the routing estimation used at CTS and the actual routes.
• More regions become congested, so the amount of NDR in the design decreases. The sequence is: shielding is first removed, then the signal nets are actually routed, and finally shielding is re-applied wherever it still fits.

KEY Actual routes congest the design, so shielding is stripped, signals routed, then shielding re-applied where possible.

Checks Done After Routing

• Open nets.
• DRC - shorts and the total DRC count.
• DRVs.
• Timing.
• DFM / DFY checks, including design metal density and multi-cut vias - note that swapping a single via for a multi-cut via can introduce hold violations.

KEY Post-route checks: opens, DRC/shorts, DRVs, timing, and DFM/DFY (density, multi-cut vias).

What Is Reported During Routing

• QoR.
• Group-by-group timing.
• Skew.
• Timing.
• Shorts and DRCs.
• DFM.

KEY Routing reports cover QoR, group-by-group, skew, timing, shorts/DRCs and DFM.