Ringfield lithographic camera
US5805365A · kind A · utility
60Cited by
19References
15Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 12, 1995 |
| Grant date | Sep 8, 1998 |
| Priority date | — |
| Expiry date | Oct 12, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70358
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection lithography camera is presented with a wide ringfield optimized so as to make efficient use of extreme ultraviolet radiation from a large area radiation source (e.g., D.sub.source .apprxeq.0.5 mm). The camera comprises four aspheric mirrors optically arranged on a common axis of symmetry with an increased etendue for the camera system. The camera includes an aperture stop that is accessible through a plurality of partial aperture stops to synthesize the theoretical aperture stop. Radiation from a mask is focused to form a reduced image on a wafer, relative to the mask, by reflection from the four aspheric mirrors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.