opc verification

**OPC Verification** is the **process of validating that OPC (Optical Proximity Correction) modifications applied to the mask design will produce acceptable patterning results** — using aerial image simulation to check that all features print within specification across the process window. **OPC Verification Checks** - **Edge Placement Error (EPE)**: Verify simulated feature edges are within tolerance of the target design. - **Bridging/Pinching**: Check for locations where features may short (bridge) or break (pinch) — critical failure modes. - **Process Window Compliance**: Verify features meet specs across the focus-dose process window, not just at nominal. - **Full-Chip**: Verify every feature on the entire chip — millions of verification sites. **Why It Matters** - **Mask Quality**: OPC errors on the mask cause systematic yield loss — verification catches errors before mask fabrication. - **Hot Spots**: Identify process weak points (hot spots) — areas most likely to fail across process variation. - **Cost**: Mask fabrication costs $100K-$500K — detecting OPC errors before mask write saves enormous rework costs. **OPC Verification** is **checking the mask before you make it** — comprehensive simulation-based validation of OPC-corrected designs for defect-free patterning.