electromigration. They cannot be applied everywhere because extra width and spacing cost area.

KEY NDR = double width + double spacing on critical nets; better SI, but it costs area.

Violations Resolved in DRC

DRC at 65nm and 90nm covers a range of design rules, including:

• Fat metal width spacing rule.
• Fat metal extension spacing rule.
• Maximum-number minimum-edge rule.
• Metal density rule (needs a Hercules license).
• Via density rule (needs a Hercules license).
• Fat metal connect rule.
• Via corner spacing rule.
• Minimum length rule.
• Via farm rule.
• Enclosed via spacing rule.
• Minimum enclosed spacing rule.
• Fat poly contact rule.
• extendMacroPinToBlockage (a new parameter).
• Special end-of-line spacing rule.
• Special notch rule.
• U-shaped metal spacing rule.
• Maximum stack level for vias in an array.
• Stud spacing.
• Multiple fat spacing.
• Enclosure rules.

KEY DRC checks geometric rules - metal width/spacing, via rules, density, enclosure, notch and end-of-line rules.

Magma vs Calibre for DRC/LVS

Magma is an implementation tool and only performs metal-level DRC. Calibre is a sign-off tool and runs DRC down to the poly and diffusion levels.