High numerical aperture ring field projection system for extreme ultraviolet lithography
An all-refelctive optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle less than substantially 12{degree}, and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15{degree}. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 {micro}m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 {micro}m. Each of the six refelecting surfaces has an aspheric departure of less than 16.0 {micro}m.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 20015690
- Resource Relation:
- Other Information: PBD: 7 Mar 2000
- Country of Publication:
- United States
- Language:
- English
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High numerical aperture ring field projection system for extreme ultraviolet lithography
High numerical aperture ring field projection system for extreme ultraviolet lithography