Pixel based machine for patterned wafers
US7454052B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 2005 |
| Grant date | Nov 18, 2008 |
| Priority date | — |
| Expiry date | Jan 5, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/9501
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method is provided for the detection of defects on a semiconductor wafer by checking individual pixels on the wafer, collecting the signature of each pixel, defined by the way in which it responds to the light of a scanning beam, and determining whether the signature is that of a faultless pixel or of a pixel that is defective or suspect to be defective. An apparatus is also provided for the determination of such defects, which comprises a stage for supporting a wafer, a laser source generating a beam that is directed onto the wafer, collecting optics and photoelectric sensors for collecting the laser light scattered by the wafer in a number of directions and generating corresponding analog signals, an A/D converter deriving from the signals digital components defining pixel signatures, and selection systems for identifying the signatures of suspect pixels and verifying whether the suspect pixels are indeed defective.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.