Servo control method and its application in a lithographic apparatus
US6420716B1 · kind B1 · utility
13Cited by
2References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1999 |
| Grant date | Jul 16, 2002 |
| Priority date | — |
| Expiry date | Dec 15, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/709
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a photolithography apparatus, accelerations of the lens unit due to vibrational disturbances are measured and used to derive a control signal which is applied to the positioning means of the wafer table and/or mask table, so as to effect compensating motions of that table. This feedforward system can be optimized to correct for motions of the lens unit in specific frequency bands, e.g. in the vicinity of the eigenfrequency of the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.