focused ion beam repair

**FIB** (Focused Ion Beam) repair is the **most established mask repair technique using a focused gallium ion beam** — the ion beam can mill away unwanted material (opaque defects) or deposit material via gas-assisted deposition (GAD) to fill missing pattern areas (clear defects). **FIB Repair Modes** - **Milling**: Gallium ions sputter material away — remove excess chrome, particles, or contamination. - **Gas-Assisted Deposition (GAD)**: Introduce a precursor gas (carbon-based or metal-organic) — the ion beam decomposes it locally, depositing material. - **Gas-Assisted Etch (GAE)**: Introduce a reactive gas (XeF₂) — enhance material removal rate and selectivity. - **Resolution**: ~10-20nm repair resolution — sufficient for most mask defects. **Why It Matters** - **Versatile**: FIB handles both additive and subtractive repairs — the Swiss Army knife of mask repair. - **Gallium Implantation**: Ga⁺ ions implant into the mask surface — can cause transmission changes and requires post-repair treatment. - **Maturity**: FIB repair has decades of development — well-understood process with established capabilities. **FIB Repair** is **the ion beam scalpel** — using focused gallium ions to precisely add or remove material for nanoscale mask defect correction.