e-beam inspection

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).