Wafer position detecting method and apparatus
US4806773A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 4, 1987 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Sep 4, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/68
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A wafer position detecting device includes a laser source, a mirror for receiving the laser beam and reflecting it to a photosensor. Optically between the laser source and the photosensor, there is located a wafer cassette containing plural semiconductor wafers in the manner that the optical path of the laser is parallel to the surface of the wafer in the cassette, namely that the laser beam can incident on the edge of the wafer parallel to the surface thereof. Relative movement is caused between the wafer and the laser beam in the direction perpendicular to the wafer surface. The space or the wafer can be detected on the basis of the output of the photosensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.