Wafer defect measuring method and apparatus
US6734960B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 2000 |
| Grant date | May 11, 2004 |
| Priority date | — |
| Expiry date | May 11, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The depth and a relative dimensional factor of a defect present in the interior of a silicon wafer are measured, and the number of such defects is calculated. A laser beam having a larger energy than the band gap of silicon is radiated obliquely to the semiconductor wafer and a scattered beam from a defect present in a subsurface layer of the wafer is detected by an image pick-up device. The temperature of the wafer is changed to at least two temperatures of T1 and T2 or to any one of plural temperatures by means of a heater and the intensity of a scattered beam is measured. It is taken into account that the light absorbance of silicon and the penetration depth of light in silicon vary depending on temperature, to determine the depth and a relative dimensional factor of an internal defect which causes scattering of light, as well as the number of such crystal defects.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.