Method and apparatus for detecting heavy metals in silicon wafer bulk with high sensitivity
US6140131A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1998 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Sep 24, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/25375
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention is to provide a method and apparatus for detecting heavy metals within the bulk of a silicon wafer with high sensitivity. An electric field is applied to a surface of the silicon wafer in order to aggregate heavy metals existing within the bulk of the silicon wafer to the surface of the wafer or the vicinity thereof, and the heavy metals aggregated to the surface of the wafer or the vicinity of the surface are analyzed. The application of an electric field is performed through corona-discharge treatment of the surface of the wafer, or through application of voltage to the surface of the wafer via a contact or non-contact electrode. Alternatively, an x-ray beam is radiated onto the surface of the silicon wafer in order to aggregate heavy metals existing within the bulk of the silicon wafer to the surface of the wafer or the vicinity thereof, and the heavy metals aggregated to the surface of the wafer or the vicinity thereof are analyzed. The method and apparatus for detecting heavy metals are simple and do not require a pre-treatment such as heat treatment which would cause secondary contamination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.