Method and apparatus for inspecting a patterned semiconductor wafer
US6774991B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 26, 2000 |
| Grant date | Aug 10, 2004 |
| Priority date | — |
| Expiry date | May 26, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95623
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for inspecting a surface of a semiconductor wafer having repetitive patterns for contaminant particles using scattered light which involves directing two beams of light at different approach angles onto the surface in a manner so as to illuminate two intersecting stripe shaped regions on the surface. An imaging lens collects scattered light from the surface as the semiconductor wafer is moving and then images the scattered light collected onto a CCD camera having a square array sensor and arranged to operate in a time delayed integration (TDI) mode. The field of view of the CCD camera is centered at the intersection of the two striped regions. Each light beam striking the surface produces a Fourier diffraction pattern of scattered light in the back focal plane of the imaging lens. In setting up the apparatus, the angle of incidence of one of the light beams is adjusted to shift one of the diffraction patterns, if necessary, so that it overlaps the other diffraction pattern. If the two approach angles are symmetrically disposed, then the two diffraction patterns overlap and adjustment of the angle of incidence of one of the beams is not necessary.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.