System for finding the orientation of a wafer
US5825913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1995 |
| Grant date | Oct 20, 1998 |
| Priority date | — |
| Expiry date | Jul 18, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2223/54453
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The invention can be used to find the orientation of a semiconductor wafer without wafer handling, i.e., in a non-contact manner. The invention uses knowledge of the position of a semiconductor wafer, and the position of an orientation feature of the wafer, to find the orientation of the wafer. According to the invention, a curved band image is formed that includes an image of an orientation feature. The curved band image is then transformed into a straight band image. The longitudinal position of the orientation feature is then determined in the coordinate system of the straight band image, which longitudinal position is then converted into an angular displacement in the coordinate system of the curved band image to provide the orientation of the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.