larger M1 pitch would prevent packing as many standard cells into a given area.

KEY Lower metals are thin to keep pitch tight for dense pins and packing; thicker top metals need wider spacing.

Advantages of NDRs

• Double width helps avoid electromigration.
• Double spacing helps avoid crosstalk.
• Helps avoid congestion on the lower metal layers.
• Improves pin accessibility of standard cells.

KEY NDRs (double width/spacing) curb EM and crosstalk and ease lower-layer congestion.

Double Via Insertion

Double vias are inserted to reduce yield loss caused by via failures. Traditionally they were added after routing, with the routing then modified to fix any resulting DRC violations.

KEY Double vias improve yield by guarding against single-via failures.

Metal Fill Insertion

During etching, chemicals cause metal loss. Metal fill (dummy metal) is inserted to compensate for that loss and keep metal density uniform across the die.

KEY Metal fill adds dummy metal to keep density uniform and offset etch-related metal loss.

Metal Slotting

Metal slotting is a technique used to avoid problems such as metal lift-off and metal erosion on wide metal shapes.

KEY Metal slotting cuts slots in wide metal to prevent lift-off and erosion.