Method for active wafer centering using a single sensor
US6760976B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 15, 2003 |
| Grant date | Jul 13, 2004 |
| Priority date | — |
| Expiry date | Jan 29, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S414/136
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for a robotic semiconductor wafer processing system to correct for wafers that have become offset or off-center during wafer processing. This is accomplished by determining the amount of offset and re-centering the wafer during wafer transport to the next process station using a single station sensor to locate the wafer center point. Each single sensor located at each station activates when the wafer's edge traverses through the sensor's path. Directional coordinates for the measured designated points on the wafer's edge are calculated, and the intersection points of two circles, analytically derived from using the measured designated points as their centers, are determined. The intersection point closest to the true wafer center position represents the measured wafer's center point. This point is compared to the true wafer center position, and the wafer is then adjusted for this difference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.