Reticle alignment system for use in lithography
US6483572B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 2001 |
| Grant date | Nov 19, 2002 |
| Priority date | — |
| Expiry date | Nov 20, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7088
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Misalignment errors in a lithographic system resulting from the effect of environmental changes on the lens system itself are detected and corrected. A fiducial on the reticle adjacent to its working area is projected through the lens. A metrology plate carried by the lens holds reference mirrors and detectors. The reference mirrors receive the resultant image and reflect it to detectors in a reflected image plane. This provides feedback to the reticle alignment system as to the extent of misalignment, if any. Correction is made by moving the reticle until alignment is achieved and detected. This motion is achieved by using a reticle chuck with linear motors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.