Balancing chuck
US4711610A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 4, 1986 |
| Grant date | Dec 8, 1987 |
| Priority date | — |
| Expiry date | Apr 4, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T409/304312
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A balancing chuck is disclosed for semiconductor wafers having a flat region which typically causes wafer imbalance on spinning equipment. The wafer's flat region is determined by a proximity sensor mounted on a centering arm overlying the wafer. The chuck is constructed to include an annular race containing a spherical counterweight. As the chuck is rotated to determine the wafer's flat region, a magnet prevents movement of the spherical counterweight within the race and allows for its subsequent alignment with the mass imbalance. A plurality of circumferential pockets are provided within the race to retain the position of the counterweight which functions as a counterbalance maintained in proper angular alignment during spinning of the chuck.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.