Defect-review SEM, reference sample for adjustment thereof, method for adjustment thereof, and method of inspecting contact holes
US6426501B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 27, 1999 |
| Grant date | Jul 30, 2002 |
| Priority date | — |
| Expiry date | May 27, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/2817
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
There is disclosed a defect-review SEM (scanning electron microscope) and method for inspecting contact holes having small aperture diameters (e.g., less than 0.05 &mgr;m) and high aspect ratios (e.g., 10 to 15) for defects with high throughput. An angular aperture control lens interlocks with an objective lens to control the convergence angle of the electron beam incident on a wafer sample to a small value (e.g., 10−5 to 10−6 rad). The beam is scanned across the sample by an upper-stage deflector and a lower-stage deflector. The beam is scanned in two stages to scan the surface of the sample vertically. The resulting secondary electrons or backscattered electrons are detected by a detector located near the back focal point of the objective lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.