Method of and apparatus for determining residual damage to wafer edges
US5790252A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1996 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Sep 27, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The invention seeks to permit evaluation of edge portion of like inclined surfaces of wafer with high accuracy without the conventional destruction process based on the selective etching process but with the contact-free, non-destructive and high accuracy optical acoustical process. To this end, the invention features determination of residual damages as crystal damages caused to wafer edge in an optical acoustical process, which comprises the steps of causing a measurement probe to face each of three exciting laser beam irradiation points on upper and lower inclined surfaces and at an accurate end of an edge portion of a semiconductor wafer, and determining a thermal response induced by the exciting laser beam by a laser interference process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.