3d afm

**3D AFM** is an **advanced atomic force microscopy technique that measures the three-dimensional profile of high-aspect-ratio semiconductor structures** — going beyond conventional surface topography to probe sidewall angles, undercuts, reentrant profiles, and trench/via geometries that conventional top-down AFM cannot access. **3D AFM Capabilities** - **Flared Tips**: Use specially designed flared (boot-shaped) or tilted tips that can probe sidewalls. - **Sidewall Angle**: Measure sidewall angles on fins, trenches, and contact holes — critical for FinFET and GAA. - **Reentrant Profiles**: Detect undercuts and reentrant features that top-down metrology misses entirely. - **CD at Depth**: Measure critical dimensions at multiple heights within a trench or fin — full profile reconstruction. **Why It Matters** - **Reference Metrology**: 3D AFM serves as a reference for calibrating scatterometry and CD-SEM models. - **Process Development**: Essential for characterizing etch profiles, spacer thickness, and fin shape. - **Advanced Nodes**: At sub-5nm nodes, 3D profile control (not just top CD) determines device performance. **3D AFM** is **seeing inside the trenches** — probing the full 3D shape of semiconductor structures for true profile metrology.