Method of positioning disk-shaped workpieces, preferably semiconductor wafers
US4376581A · kind A · utility
10Cited by
3References
5Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1980 |
| Grant date | Mar 15, 1983 |
| Priority date | — |
| Expiry date | Dec 29, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/682
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
In the photoexposure of semiconductor wafers for the production of circuit elements, the wafers are placed in a prealignment position before being transferred to the exposure stage. A chuck acting as a prepositioning stage is rotatable by one servomotor to set the wafer in its appropriate angular position (.phi. adjustment) and is shiftable by respective servomotors in the X and Y directions. Servomotor control is effected by optical means detecting a noncircular edge portion of the wafer as well as alignment marks on the wafer inwardly of the edge thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.