Optical distortion reduction in projection systems
Techniques are disclosed for optical distortion reduction in projection systems for scanning projection and/or lithography. A projection system includes an illumination system configured to generate illumination radiation for generating an image of an object to be projected onto an image plane of the projection system. The illumination system includes a field omitting illumination condenser configured to receive the illumination radiation from a radiation source and provide a patterned illumination radiation beam to generate the image of the object, wherein the patterned illumination radiation beam comprises an omitted illumination portion corresponding to a ridge line of a roof prism disposed within an optical path of the projection system.
1. A projection system comprising:
an illumination system configured to generate illumination radiation for generating an image of an object to be projected onto an image plane of the projection system, the illumination system comprising:
a field omitting illumination condenser configured to receive the illumination radiation from a radiation source and provide a patterned illumination radiation beam to generate the image of the object, wherein the patterned illumination radiation beam comprises an omitted illumination portion corresponding to a ridge line of a roof prism disposed within an optical path of the projection system.
2. The projection system of claim 1 , wherein:
the field omitting illumination condenser comprises a field blocking aperture insert configured to block a portion of the received illumination radiation to generate the patterned illumination radiation beam.
3. The projection system of claim 2 , wherein:
the illumination system comprises a field blocking aperture insert selection mechanism configured to select one of a plurality of field blocking aperture inserts to select a particular beam shape for the patterned illumination radiation beam.
4. The projection system of claim 2 , wherein:
a beam shape for the patterned illumination radiation beam comprises a diamond shaped exterior perimeter and a partially or fully omitted interior strip aligned with a projection of the ridge line of the roof prism.
5. The projection system of claim 2 , wherein:
a beam shape for the patterned illumination radiation beam comprises a hexagonally shaped exterior perimeter and a partially or fully omitted interior strip aligned with a projection of the ridge line of the roof prism.
6. The projection system of claim 1 , wherein:
the field omitting illumination condenser comprises a field omitting light pipe configured to spatially divert the received illumination radiation to generate the patterned illumination radiation beam.
7. The projection system of claim 6 , wherein:
the field omitting light pipe comprises first and second triangular shaped light pipe chambers that are adjoining each other at an entrance of the field omitting illumination condenser and that are spaced from each other at an exit of the field omitting illumination condenser to form the omitted illumination portion of the patterned illumination radiation beam.
8. The projection system of claim 6 , wherein:
a beam shape for the patterned illumination radiation beam comprises a diamond shaped exterior perimeter and a partially or fully omitted interior strip aligned with a projection of the ridge line of the roof prism.
9. The projection system of claim 6 , wherein:
a beam shape for the patterned illumination radiation beam comprises a hexagonally shaped exterior perimeter and a partially or fully omitted interior strip aligned with a projection of the ridge line of the roof prism.
10. The projection system of claim 6 , wherein:
the illumination system comprises a field omitting illumination condenser selection mechanism configured to select one of a plurality of field omitting illumination condensers to select a particular beam shape for the patterned illumination radiation beam.
11. A projection system comprising:
an illumination system configured to generate illumination radiation for generating an image of an object to be projected onto an image plane of the projection system, the illumination system comprising:
a plurality of illumination condensers each configured to receive the illumination radiation from a radiation source and provide a patterned illumination radiation beam to generate the image of the object; and
a condenser selection mechanism configured to select one of the plurality of illumination condensers to select a particular beam shape for the patterned illumination radiation beam, wherein at least one particular beam shape for the patterned illumination radiation beam comprises an exterior perimeter and a partially or fully omitted interior strip aligned with a projection of a ridge line of a roof prism.
12. The projection system of claim 11 , wherein:
the exterior perimeter comprises a diamond shaped exterior perimeter.
13. The projection system of claim 11 , wherein:
the exterior perimeter comprises a hexagonally shaped exterior perimeter.
14. A method comprising:
generating, by an illumination system of a projection system, illumination radiation for generating an image of an object to be projected onto an image plane of the projection system;
receiving, by a field omitting illumination condenser of the illumination system, the illumination radiation;
providing, by the field omitting illumination condenser, a patterned illumination radiation beam to generate the image of the object, wherein the patterned illumination radiation beam comprises an omitted illumination portion corresponding to a ridge line of a roof prism disposed within an optical path of the projection system.
15. The method of claim 14 , further comprising:
selecting, via a field blocking aperture insert selection mechanism, one of a plurality of field blocking aperture inserts to select a particular beam shape for the patterned illumination radiation beam; and
applying the selected field blocking aperture insert to the received illumination radiation by inserting the selected field blocking aperture insert into the field omitting illumination condenser, wherein the selected field blocking aperture insert is configured to block a portion of the received illumination radiation to generate the patterned illumination radiation beam.
16. The method of claim 14 , further comprising:
selecting, via a field omitting illumination condenser selection mechanism, one of a plurality of field omitting illumination condensers to select a particular beam shape for the patterned illumination radiation beam; and
applying the selected field omitting illumination condenser to the received illumination radiation by placing the selected field omitting illumination condenser in an optical path of the illumination radiation.
17. The method of claim 16 , wherein:
the selected field omitting illumination condenser comprises a field blocking aperture insert configured to block a portion of the received illumination radiation to generate the patterned illumination radiation beam.
18. The method of claim 16 , wherein:
the selected field omitting illumination condenser comprises a field omitting light pipe configured to spatially divert the received illumination radiation to generate the patterned illumination radiation beam.
19. The method of claim 14 , wherein:
a beam shape for the patterned illumination radiation beam comprises a diamond shaped exterior perimeter and a partially or fully omitted interior strip aligned with a projection of the ridge line of the roof prism.
20. The method of claim 14 , wherein:
a beam shape for the patterned illumination radiation beam comprises a hexagonally shaped exterior perimeter and a partially or fully omitted interior strip aligned with a projection of the ridge line of the roof prism.