aims

**AIMS** (Aerial Image Measurement System) is a **dedicated metrology tool that emulates the optical conditions of a lithographic scanner to image mask features** — reproducing the exact wavelength, NA, illumination conditions, and partial coherence of the production scanner to predict how mask patterns and defects will print on the wafer. **AIMS Capabilities** - **Emulation**: Matches scanner illumination (wavelength, NA, sigma, polarization) — images the mask as the scanner would. - **Through-Focus**: Acquires aerial images at multiple defocus positions — determines printability across the process window. - **CD Measurement**: Extracts CD from the aerial image — predicts wafer-level CD from the mask. - **Defect Review**: After automatic inspection identifies suspect defects, AIMS determines their printability. **Why It Matters** - **Defect Disposition**: AIMS is the final arbiter for mask defect printability — "will this defect print or not?" - **Repair Verification**: After mask repair, AIMS confirms the repair was successful — verify printability, not just physical restoration. - **Cost**: AIMS review is essential but expensive — tools cost $10M+ and measurement is time-consuming. **AIMS** is **the scanner simulation microscope** — emulating lithographic imaging conditions to predict exactly how mask features will appear on the wafer.