Projection exposure apparatus having an off-axis alignment system and method of alignment therefor
US5243195A · kind A · utility
722Cited by
9References
11Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1992 |
| Grant date | Sep 7, 1993 |
| Priority date | — |
| Expiry date | Dec 29, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7088
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An exposure apparatus for exposing mask patterns on a sensitive plate comprises a set (for X and Y direction) of a laser interferometer for measuring a position of a wafer stage and satisfying Abbe's condition with respect to a projection lens and a set (for X and Y direction) of the laser interferometer and satisfying Abbe's condition with respect to off-axis alignment system. When a fiducial mark on the wafer stage is positioned directly under the projection lens, a presetting is performed so that measuring values by the two sets of laser interferometers are equal to each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.