E-beam inspection uses a focused electron beam to scan the wafer surface, achieving higher resolution defect detection than optical methods and enabling voltage contrast imaging. Resolution: Electron beam resolves features <5nm, far exceeding optical inspection limits (~30nm). Essential for detecting defects at advanced nodes. Voltage contrast: Electrically connected and disconnected features appear different under e-beam due to charge differences. Detects buried electrical defects invisible to optical inspection (open vias, broken contacts). Modes: Die-to-die: Compare images of nominally identical die patterns. Differences are defects. Design-based: Compare to design layout. Detect systematic pattern failures. Physical defects: Particles, residues, pattern deformations detected by image contrast. Electrical defects: Voltage contrast reveals open circuits, short circuits, high-resistance contacts without electrical probing. Throughput limitation: E-beam scanning is much slower than optical inspection. Cannot inspect full wafers at high sensitivity in production time. Sampling: Typically used for targeted inspection of critical layers or hot spots identified by optical inspection or design analysis. Multi-beam: Next-generation e-beam inspection uses multiple parallel beams (100+) to increase throughput dramatically. Applications: Contact/via open detection, advanced patterning defects, yield learning at new technology nodes, failure analysis support. Hot-spot inspection: Focus e-beam inspection on design-identified weak points for efficient defect sampling. Vendors: KLA (eScan), Applied Materials (PROVision), ASML (HMI multi-beam).