Illumination optical system and exposure apparatus
AssigneeCanon Kabushiki Kaisha
InventorToshihiko Tsuji
Life of this patent
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Abstract
An exposure apparatus includes an illumination optical system for illuminating a reflection mask that forms a pattern, by using light from a light source, wherein the illumination optical system includes a field stop that defines an illuminated area on the reflection mask, and has an opening, and an imaging system for introducing the light from the opening in the field stop into the reflection mask, the imaging system being a coaxial optical system, wherein a principal ray of the imaging system at a side of the reflection mask forming an inclination angle to a common axis of the coaxial optical system, the inclination angle being approximately equal to an angle between a principal ray of the projection optical system at the side of the reflection mask and a normal to a surface of the reflection mask.
Claims18
An exposure apparatus comprising:
- an illumination optical system for illuminating a pattern of a reflection mask, by using light from a light source, wherein said illumination optical system includes:
- a field stop that defines an illuminated area on the reflection mask, and has an opening;
- and
- an imaging system for directing the light from the opening in the field stop into the reflection mask, the imaging system being a coaxial optical system;
- and
- a projection optical system for projecting the pattern on the reflection mask onto a substrate, wherein a principal ray of the imaging system at a side of the reflection mask forming an inclination angle to a common axis of the coaxial optical system, the inclination angle being approximately equal to an angle between a principal ray of said projection optical system at the side of the reflection mask and a normal to a surface of the reflection mask.
A device fabricating method comprising the steps of:
- exposing an object using an exposure apparatus;
- and
- developing the exposed object,
- wherein said exposure apparatus includes:
- an illumination optical system for illuminating a pattern of a reflection mask, by using light from a light source, wherein said illumination optical system includes:
- a field stop that defines an illuminated area on the reflection mask, and has an opening;
- and
- an imaging system for directing the light from the opening in the field stop into the reflection mask, the imaging system being a coaxial optical system;
- and
- a projection optical system for projecting the pattern on the reflection mask onto a substrate, wherein a principal ray of the imaging system at a side of the reflection mask forming an inclination angle to a common axis of the coaxial optical system, the inclination angle being approximately equal to an angle between a principal ray of said projection optical system at the side of the reflection mask and a normal to a surface of the reflection mask.
Dependencies are inferred from the claim text.