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.