Projection optical system, fabrication method thereof, exposure apparatus and exposure method
AssigneeNikon Corporation
InventorYasuhiro Omura
Life of this patent
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Abstract
Disclosed is a projection optical system capable of ensuring good optical performance virtually without effects of birefringence of fluorite by for example, controlling an angle difference between an optical axis and a predetermined axis of a fluorite lens to a predetermined allowable amount. The projection optical system for forming an image of a first surface (R: reticle) on a second surface (W: wafer) includes at least two light-transmissive crystal members formed of a crystal material belonging to a cubic system. In at least the two light-transmissive crystal members, an angle difference is set at 1° between the optical axis and any one of crystal axes [111], [100] and [110].
Claims48
A projection optical system for forming an image of a first surface on a second surface, comprising:
- at least two light-transmissive crystal members formed of a crystal material belonging to a cubic system,
- wherein at least one of an angle difference between an optical axis and any one of crystal axes [111], [100] and [110] in at least the two light-transmissive crystal members and an angle difference of a relatively rotational angle between predetermined crystal axes around the optical axis from a predetermined value in at least the two light-transmissive crystal members is set at 1° or less.
A projection optical system for forming an image of a first surface on a second surface, comprising:
- at least two light-transmissive crystal members formed of a crystal material belonging to a cubic system,
- wherein, when an area having a difference between orientations of crystal axes exists in at least the two light-transmissive crystal members, relative angle difference thereof is 2° or less.
A fabrication method of a projection optical system including at least two light-transmissive crystal embers formed of a crystal material belonging to a cubic system and for forming an image of a first surface on a second surface, the method comprising:
- a design step of designing to allow an optical axis of each of at least the two light-transmissive crystal members to coincide with any one predetermined crystal axis of crystal axes [111], [100] and [110];
- and
- a fabrication step of fabricating at least the two light-transmissive crystal members such that an angle difference is set at 1° or less between the predetermined crystal axis and the optical axis.
An optical system comprising:
- at least the two light-transmissive crystal members formed of a crystal material belonging to a cubic system,
- wherein at least one of an angle difference between an optical axis and any one of crystal axes [111], [100] and [110] in at least the two light-transmissive crystal members and an angle difference of a relatively rotational angle between predetermined crystal axes around the optical axis from a predetermined value in at least the two light-transmissive crystal members is set at 1° or less.
An optical system comprising:
- at least two light-transmissive crystal members formed of a crystal material belonging to a cubic system,
- wherein, when an area having a difference between orientations of crystal axes exists in at least the two light-transmissive crystal members, relative angle difference thereof is 2° or less.
A fabrication method of a projection optical system including at least two light-transmissive crystal members formed of a crystal material belonging to a cubic system and for forming an image of a first surface on a second surface, the method comprising:
- a design step of designing to allow an optical axis of each of at least the two light-transmissive crystal members to coincide with any one predetermined crystal axis of crystal axes [111], [100] and [110];
- and
- a fabrication step of fabricating at least the two light-transmissive crystal hers such that an angle difference is set at 1° or less between the predetermined crystal axis and the optical axis.
Dependencies are inferred from the claim text.