Multi-Corner Multi-Mode (MCMM) — analyzing chip timing across all combinations of operating conditions (corners) and functional modes, ensuring the design works under every real-world scenario.
What Is a Corner?
- A specific combination of Process, Voltage, and Temperature (PVT)
- Process: SS (slow-slow), TT (typical), FF (fast-fast) — manufacturing variation
- Voltage: Nominal ± 10% (e.g., 0.75V nominal → check 0.675V and 0.825V)
- Temperature: -40°C to 125°C (automotive) or 0°C to 100°C (consumer)
Why Multiple Corners?
- Setup (max delay): Check at slow corner (SS, low V, high T)
- Hold (min delay): Check at fast corner (FF, high V, low T)
- Leakage power: Worst at high T
- Each corner can reveal different violations
What Is a Mode?
- A functional operating configuration with different clock frequencies and active blocks
- Examples: Full-speed mode, low-power mode, test/scan mode, boot mode
- Each mode has different timing constraints
Typical MCMM Analysis
- 5–10 PVT corners × 3–5 operating modes = 15–50 analysis scenarios
- Advanced designs: Up to 100+ scenarios
- Tool runs STA on all scenarios simultaneously (concurrent MCMM)
Impact
- MCMM is mandatory for signoff — single-corner analysis misses real failures
- First silicon success rate correlates strongly with MCMM thoroughness
MCMM ensures the chip works not just in typical conditions but in every combination of manufacturing variation, voltage, and temperature it will ever encounter.