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U.S. Department of Energy
Office of Scientific and Technical Information

High numerical aperture ring field projection system for extreme ultraviolet lithography

Patent ·
OSTI ID:20015690
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:
US Department of Energy
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
20015690
Country of Publication:
United States
Language:
English