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.